Reduced bone density is recognized as a predictor for potential complications in reverse shoulder arthroplasty (RSA). While humeral and glenoid planning based on preoperative computed tomography (CT) scans assist in implant selection and position, reproducible methods for quantifying the patients' bone density are currently not available. The purpose of this study was to perform bone density analyses including patient-specific calibration in an RSA cohort based on preoperative CT imaging. It was hypothesized that preoperative CT bone density measures would provide objective quantification of the patients' humeral bone quality.

This study consisted of 3 parts, (1) analysis of a patient-specific calibration method in cadaveric CT scans, (2) retrospective application in a clinical RSA cohort, and (3) clustering and classification with machine learning (ML) models. Forty cadaveric shoulders were scanned in a clinical CT and compared regarding calibration with density phantoms, air muscle, and fat (patient-specific) or standard Hounsfield unit. Postscan patient-specific calibration was used to improve the extraction of 3-dimensional regions of interest for retrospective bone density analysis in a clinical RSA cohort (n = 345). ML models were used to improve the clustering (Hierarchical Ward) and classification (support vector machine) of low bone densities in the respective patients.

The patient-specific calibration method demonstrated improved accuracy with excellent intraclass correlation coefficients for cylindrical cancellous bone densities (intraclass correlation coefficient >0.75). Clustering partitioned the training data set into a high-density subgroup consisting of 96 patients and a low-density subgroup consisting of 146 patients, showing significant differences between these groups. The support vector machine showed optimized prediction accuracy of low and high bone densities compared to conventional statistics in the training (accuracy = 91.2%; area under curve = 0.967) and testing (accuracy = 90.5%; area under curve = 0.958) data set.

Preoperative CT scans can be used to quantify the proximal humeral bone quality in patients undergoing RSA. The use of ML models and patient-specific calibration on bone mineral density demonstrated that multiple three-dimensional bone density scores improved the accuracy of objective preoperative bone quality assessment. The trained model could provide preoperative information to surgeons treating patients with potentially poor bone quality.

The utilization of stemless anatomic total shoulder arthroplasty is on the rise. Epiphyseal fixation leads to radiological bone remodeling, which has been reported to exceed 40% in certain studies series. The aim of this study was to present the clinical and radiological outcomes of a stemless implant with asymmetric central epiphyseal fixation at an average follow-up of 31 months.

This retrospective multicenter study examined prospective data of patients undergoing total anatomic arthroplasty with intuitive shoulder arthroplasty Stemless implant and followed up at least 2 years. Clinical assessment included preoperative and final follow-up measurements of active range of motion, Constant score, and Subjective Shoulder Value. Anatomical epiphyseal reconstruction and bone remodeling at the 2-year follow-up were assessed by standardized computed tomography scanner (CT scan). Statistical analysis employed unpaired Student's t-test or chi-squared test depending on the variable type, conducted using EasyMedStat software (version 3.22; www.easymedstat.com).

Fifty patients (mean age 68 years, 62% females) were enrolled, with an average follow-up of 31 months (24-44). Primary osteoarthritis (68%) with type A glenoid (78%) was the prevailing indication. The mean Constant score and Subjective Shoulder Value improved significantly from 38 ± 11 to 76 ± 11 (P < .001) and from 31% ± 16 to 88% ± 15 (P < .001) respectively at the last follow-up. Forward elevation, external rotation, and internal rotation range of motion increased by 39° ± 42, 28° ± 21 and 3,2 ± 2,5 points respectively, surpassing the Minimally Clinically Important Difference after total shoulder arthroplasty. No revisions were necessary. CT scans identified 30% osteolysis in the posterior-medial calcar region, devoid of clinical repercussions. No risk factors were associated with bone osteolysis.

At an average follow-up of 31 months, intuitive shoulder arthroplasty Stemless implant provided favorable clinical results. CT analysis revealed osteolysis-like remodeling in the posterior-medial zone of the calcar (30%), without decline in clinical outcomes and revisions. Long-term follow-up studies are mandated to evaluate whether osteolysis is associated with negative consequences.

This study evaluated the effects of bony increased offset (BIO) and metallic augments (MAs) on primary reverse shoulder arthroplasty (RSA) baseplate stability in cadaveric specimens with variable bone densities.

Thirty cadaveric specimens were analyzed in an imaging and biomechanical investigation. Computed tomography (CT) scans allowed for preoperative RSA planning and bone density analysis. Three correction methods of the glenoid were used: (1) corrective reaming with a standard baseplate, which served as the reference group (n = 10); (2) MA-RSA (n = 10); and (3) angled BIO-RSA (n = 10). Each augment group consisted of 10° (n = 5) and 20° (n = 5) corrections. Biomechanical testing included cyclic loading in an articulating setup, with optical pre- and post-cyclic micromotion measurements in a rocking horse setup.

There were no differences in bone density between groups based on CT scans (p > 0.126). The BIO-RSA group had higher variability in micromotion compared to the MA-RSA and reference groups (p = 0.013), and increased total micromotion compared to the reference group (p = 0.039). Both augmentations using 20° corrections had increased variance in rotational stability compared to the reference group (p = 0.043). Micromotion correlated with the subchondral bone density in the BIO-RSA group (r = -0.63, p = 0.036), but not in the MA-RSA (p > 0.178) or reference (p > 0.117) groups.

Time-zero baseplate implant fixation is more variable with BIO-RSA and correlates with bone density. Corrections of 20° with either augmentation approach increase variability in rotational micromotion. The preoperative quantification of bone density may be useful before utilizing 20° of correction, especially when adding a bone graft in BIO-RSAs.

As the incidence of reverse total shoulder arthroplasty (rTSA) continues to rise, better understanding of the long-term risks and complications is necessary to determine the best choice of implant. The majority (75%) of rTSAs performed in New Zealand use either SMR (Systema Multiplana Randelli; Lima-LTO) or Delta Xtend (DePuy Synthes). The aim of this registry-based study was to compare implant survival, risk of revision, and reasons for revision between the 2 most frequently used rTSA prostheses: SMR and Delta Xtend.

Using data from the New Zealand Joint Registry between 1999 and 2022, we identified 5891 patients who underwent rTSA using either SMR cementless (62.8%) or Delta Xtend prostheses (37.2%). Delta Xtend was subdivided into cementless (31.4% of total) and cemented humeral stem (5.8% of total) subgroups for analysis. Revision-free implant survival and functional outcomes (Oxford Shoulder Score [OSS] at 6 months, 5 years, and 10 years were adjusted by age, American Society of Anesthesiologists [ASA] grade, indication, sex, and surgeon volume for between-group comparisons.

Ten-year revision-free implant survival was 93.0%, 92.5%, and 95.8% for Delta Xtend cemented, Delta Xtend cementless, and SMR, respectively. The Delta Xtend cemented implant had a 2-fold higher adjusted revision risk compared with both the Delta Xtend cementless and the SMR cementless implants (hazard ratio [HR] = 2.04, P = .011; and HR = 2.59, P < .001, respectively). There was no significant difference between the Delta Xtend cementless and SMR cementless groups (HR = 1.28, P = .129). The Delta Xtend cemented group was significantly (P ≤ .01) older, had more comorbidities (ASA 3 or 4), female, and indicated for fracture compared with other groups. The most common reason(s) for revision was aseptic loosening and infection for Delta Xtend cementless; aseptic loosening, instability or dislocation, and infection for Delta Xtend cemented; and aseptic loosening alone for SMR cementless. Average OSS was significantly lower in Delta Xtend cemented compared with Delta Xtend cementless and SMR cementless at 6 months (30.8, 35.9 vs. 35.6, respectively, P < .01) and 5 years (37.4, 40.7 vs. 39.5, respectively, P < .01).

Overall, we found that the Delta Xtend cemented group had more than a 2-fold risk of revision compared with Delta Xtend cementless and SMR cementless groups, whereas there was no difference in revision risk between the Delta Xtend and SMR cementless prostheses. As the incidence of rTSA continues to rise, better understanding of the long-term risks and complications is necessary to determine the best choice of implant.

Inverted-bearing reverse shoulder arthroplasty (IB-RSA) is characterized by a polyethylene glenosphere and a metallic humeral liner to minimize polyethylene wear and debris secondary to impingement between the humerus and glenoid neck. IB-RSA long-term survivorship, complication and revision rates, as well as clinical and radiographic outcomes have not been reported yet.

This is a monocentric retrospective study on a consecutive series of 151 patients who underwent primary IB-RSA from January 2009 to September 2015 and were evaluated clinically and radiologically at the minimum 8-year follow-up. All complications and reoperations were recorded. Survivorship analysis with any revision surgery as endpoint was done using Kaplan-Meier survival curves.

Seventy-eight patients (follow-up rate 51.7%) were reviewed at a mean follow-up of 10.1 ± 1.9 years. At 10 years, the revision-free survival was 98.7% (95% confidence interval: 94.8-99.7). Sixteen complications (10.6%) were observed: 2 axillary nerve injuries, 2 infections, 2 glenoid loosening (which stabilized within 1 year), 2 cases of otherwise unexplained painful stiffness, 4 acromial fractures, 1 post-traumatic scapular pillar fracture, and 3 post-traumatic humeral periprosthetic fractures. Two patients were revised due to infection. No cases of late glenoid loosening and humeral loosening were observed. The revision rate was 1.3%. All the clinical scores and range of motion significantly improved at the last follow-up compared with preoperative status: final Constant score was 66.1 ± 17.4, Subjective Shoulder Value 79.1 ± 20.9, and the American Shoulder and Elbow Surgeons 82.2 ± 17.7. Scapular notching was observed in 51.4% of patients: only 1 case of grade 3 notching was observed in an early glenoid subsidence case.

Primary IB-RSA appears to be a safe and effective procedure and does not present specific implant-associated complications at long-term follow-up. Radiographic analysis showed that inverting the biomaterials leads to a distinct kind of notching with mainly mechanical features.

This study evaluated the effect of three-dimensional (3D) volumetric humeral canal fill ratios (VFR) of reverse shoulder arthroplasty (RSA) short and standard stems on biomechanical stability and bone deformations in the proximal humerus.

Forty cadaveric shoulder specimens were analyzed in a clinical computed tomography (CT) scanner allowing for segmentation of the humeral canal to calculate volumetric measures which were verified postoperatively with plain radiographs. Virtual implant positioning allowed for group assignment (VFR < 0.72): Standard stem with low (n = 10) and high (n = 10) filling ratios, a short stem with low (n = 10) and high filling ratios (n = 10). Biomechanical testing included cyclic loading of the native bone and the implanted humeral component. Optical recording allowed for spatial implant tracking and the quantification of cortical bone deformations in the proximal humerus.

Planned filling ratios based on 3D volumetric measures had a good-to-excellent correlation (ICC = 0.835; p < 0.001) with implanted filling ratios. Lower canal fill ratios resulted in significantly higher variability between short and standard stems regarding implant tilt (820 N: p = 0.030) and subsidence (220 N: p = 0.046, 520 N: p = 0.007 and 820 N: p = 0.005). Higher filling ratios resulted in significantly lower bone deformations in the medial calcar area compared to the native bone, while the bone deformations in lower filling ratios did not differ significantly (p > 0.177).

Lower canal filling ratios maintain dynamic bone loading in the medial calcar of the humerus similar to the native situation in this biomechanical loading setup. Short stems implanted with a low filling ratio have an increased risk for implant tilt and subsidence compared to high filling ratios or standard stems.

The purpose of this study was to examine the radiographic and clinical outcomes of stemless reverse total shoulder arthroplasty (RTSA) after a minimum 2-year follow-up.

Between July 2018 and March 2023, 50 patients underwent 50 stemless RTSA with the Lima component. Twenty-eight patients with a follow-up of more than 2 years were reviewed. The average age was 71.9 years (range, 61-85 years), and the average follow-up period was 2.2 years (range, 2.0-5.1 years). Bone marrow density of the proximal humerus was measured before RTSA. We evaluated preoperative and postoperative range of motion, clinical score, radiographic change, and postoperative complications.

Significant increases were observed postoperatively in forward flexion (112.0°-162.5°, P<0.01) and internal rotation (from L3 to T12 level, P<0.05). No changes were observed in external rotation (from 43.0° to 45.2°, P=0.762). The clinical scores improved for Korean Shoulder Scoring system (from 64 to 93, P<0.01) and American Shoulder and Elbow Surgeons score (from 17.5 to 27.3, P<0.01). Although radiolucent lines of less than 2 mm were observed in all cases, no osteolysis and loosening of the stemless humeral component was found. Scapular notching was observed in 18 cases (64.3%).

Stemless RTSA showed good radiographic and clinical results after a minimum 2-year follow-up. Level of evidence: IV.

There have been tremendous modifications to the humeral component since Paul Grammont first introduced the reverse total shoulder arthroplasty in 1985. The purpose of this article is to review historical design features and their drawbacks and to summarize the clinical outcomes of modern designs.

Decreasing the neck-shaft angle and increasing humeral lateralization have helped address problems of scapular notching and limited internal and external rotation that were common with traditional designs. Advancements in proximal porous coatings have also facilitated the development of short-stem and stemless implants, which decreases the need for cement fixation and allows preservation of bone stock. Moreover, a reduction in stem length with smaller metaphyseal and diaphyseal filling ratios may limit stress shielding. Current humeral implants have an aseptic loosening rate less than 1%. Despite promising results, many of these new humeral design features do not have long-term data and continued surveillance of their performance is necessary. The humeral stem design significantly influences clinical and radiographic outcomes. Surgeons should be mindful of these design variables to increase impingement-free range of motion, minimize scapular notching, reduce stress shielding, and improve implant survivorship.

Reverse shoulder arthroplasty (RSA) is used commonly for a wide range of indications. The complications after the total shoulder replacements have been reported to be related with the prosthesis design. The type of the humeral stem is a consideration to reduce complication. Radiographic changes are seen at a high rate with new-generation press-fit stems.

This study aims to reduce proximal humeral bone loss after RSA could have been achieved with adjustable humeral stem when compared with monoblock stem.

A retrospective analysis was made of 52 patients treated with RSA using a press-fit humeral stem prosthesis. The patients were separated into two groups according to the type of humeral stem. The first group included 26 patients (18 females, 8 males) who underwent RSA using adjustable humeral stem. The second group included of 26 patients (17 females, 9 males) for whom monoblock humeral stem was used. Clinical and radiological evaluations were made based on the information obtained at 1, 3, 6, 12, and 18 months postoperatively. The follow-up duration was at least 18 months.

There was no statistical difference between the adjustable and monoblock groups in respect to gender, age, height, and weight. According to the functional measurements at the final follow-up, no statistically significant difference was determined between the groups with respect to the Constant, UCLA, Oxford, DASH, and VAS values. In terms of radiographic changes, both groups were seen to have been similarly affected. It was found that, irrespective of the stem type used, the humeral side radiographic adaptation was found to be high, which negatively affected the functional results (P < 0.05).

The increased radiographic stress shielding adaptation leading to humeral osteolysis was found to have a negative effect on the functional results with the press-fit technique irrespective of stem design.

Cementless reverse shoulder arthroplasty has become increasingly popular because of the improved implant design, porous ingrowth surface, and surgical techniques. When avoiding the risks of cement use, a press-fit arthroplasty stem that has been implanted may not feel immediately stable, especially if the medullary canal size is in between standard stem diameters. To help surgeons improve fixation and avoid overstuffing the medullary canal, we present the matchstick autograft augmentation technique. The use of humeral autograft, analogous to impaction grafting in hip arthroplasty, has been reported to have promising short-term outcomes2,3. This technique of using humeral autograft material, dubbed matchstick autografts because of their shape and size, allows for optimization of humeral stem stability with the option of smaller cementless humeral implants. By avoiding overstuffing of the medullary canal, this technique aims to reduce the incidences of intraoperative fracture, postoperative stress shielding, and potential implant loosening4-6.

Cementless reverse total shoulder arthroplasty is routinely performed via the anterosuperior approach7; however, a deltopectoral approach can be utilized if desired. The canal is sequentially broached with implant trials until the tactile feedback demonstrates axial and rotational stability. In cases in which tactile feedback during implantation demonstrates slight movement, the smaller implant size can be selected and augmented with matchstick autograft. An oscillating saw is utilized to cut the edges of the previously resected humeral head in order to expose the subchondral bone surface. Graft sticks about 20 mm in length and 1 to 3 mm in width are then fashioned. Humeral trials are then implanted with the matchstick grafts placed lengthwise alongside the humeral stem. Axial and rotational press-fit is again assessed. If adequate, the formal humeral implant is selected and implanted in position. As in conventional impaction grafting, the grafts are compressed to the side of the humeral canal, but they offer more corticocancellous structure than bone chips. This technique is applicable even in some fracture scenarios.

When a specific press-fit humeral stem size does not achieve adequate stability, there are typically 3 surgical alternatives. First, a larger stem size can be selected. Second, the implant can be inserted deeper to achieve press-fit stability. Third, cement can be added to fill the medullary canal and create immediate stability.

When implanting the humeral prosthesis, the operating surgeon's primary goal is stem stability. When faced with lack of stability, the surgeon can select a larger humeral stem, risking stress shielding; implant the stem deeper, compromising length and risking humeral fracture; or consider a cemented implant. In order to minimize the risk of intraoperative cardiopulmonary events and complicated subsequent revision surgeries8, the use of cement should be avoided if at all possible. Shoulder surgeons have reported grafting techniques, analogous to hip impaction grafting, that have yielded good success3. The technique that we describe utilizes a matchstick structural autograft that helps improve cementless fixation in primary humeral implantation cases and allows for the use of a smaller stem. The structural shape of the graft allows this technique to be utilized even in selected proximal humeral fractures.

Other studies have reported on the use of softer cancellous autografts to stabilize humeral implants in shoulder arthroplasty. In a study of 286 arthroplasties with a minimum follow-up of 2 years, Lucas et al. reported that 267 humeral stems (93.3%) had not subsided3. Humphrey and Bravman used cancellous autograft to achieve metaphyseal centering of the humeral component in 53 patients, with no cases of humeral implant loosening at 12 months2. Lo et al. reported 91% tuberosity healing in their series of cementless reverse total shoulder arthroplasties augmented with matchstick autografts1, with no cases of aseptic humeral stem loosening. Montemaggi et al. used matchstick autografts to augment 46 primary cementless reverse total shoulder arthroplasties and found zero instances of humeral loosening at 1-year follow-up9.

The strongest humeral matchstick grafts come from the subchondral surface.After creating the graft, it is palpated for structural integrity. A stiffer or softer graft can be chosen, depending on surgeon preference.Surgeons can try impacting the graft with humeral trials to assess the stem stability prior to final implantation.

RTSA = reverse total shoulder arthroplastyFX = fracture3D CT = 3-dimensional computed tomographyXR = x-rayFU = follow-up.

This study aimed to assess the radiographic proximal humerus bony adaptations to stress shielding and associated clinical outcomes following stemless total shoulder arthroplasty.

A retrospective review of all patients who underwent stemless total shoulder arthroplasty surgery at our centre from 2010 to 2020 was performed.

In total, 115 stemless total shoulder arthroplasty utilising a single implant design with a minimum one-year follow-up were identified over a 10-year period. The median follow-up was 3.5 years (range: 1-8.9 years). Evidence of stress shielding was observed in 20 cases (17%), (9 mild (8%), 0 moderate (0%), 11 severe (9%). No significant differences were seen between stress shielding and gender, body mass index, post-operative range-of-motion, patient satisfaction, or Oxford shoulder score. No significant differences were seen between the operative technique and stress shielding. No cases had evidence of humeral lucency. In total, 24 cases (21%) had evidence of glenoid lucency of Lazarus grade 0-3. No cases had Lazarus grades 4 or 5. There was no association between stress shielding and humeral lucency, glenoid lucency, or revision procedure.

Stress shielding in this study occurred at lower rates than anticipated following stemless total shoulder arthroplasty and was not associated with radiographic evidence of lucency, revision procedures, or adverse effect on clinical outcome measures.

Reverse shoulder arthroplasty (RSA) is popular for the treatment of degenerative glenohumeral joint disease. Bone remodeling around the humeral stem related to stress shielding (SS) has been described. This review focuses on the specific radiological characteristics, risk factors, and clinical consequences of SS in RSA.

A meticulous review was conducted of articles published between 2013 and 2023. Data on the definition, risk factors, and clinical impact of stress shielding were recorded.

Twenty-eight studies describing 2691 patients who had undergone RSA were included. The mean age of patients ranged from 63 to 80 years with mean follow-up periods of 12 months to 9.6 years. The prevalence of SS reached up to 39% at a 2-year follow-up. Females and elderly are typically at higher risk due to osteopenia. SS was more frequent with the use of long stems(>100 mm) compared to short stems(<100 mm). Stem design, onlay or inlay, and neck-shaft-angle did not influence SS. Frontal misalignment and a high filling ratio are riskfactors for SS. Biological factors also contribute to SS, associated with scapular notching. No correlation was found between SS and clinical outcomes.

SS is common in patients with cementless implants after RSA, especially in female and elderly patients. It can be limited by implanting stems with a low diaphyseal filling-ratio, in correct coronal alignment. Risk factors for polyethylene debris, primarily scapular notching, should be avoided. The authors found no clinical consequences of stress shielding, but longer-term follow-up studies are required to confirm these findings.

Several factors affect the incidence of osteopenia with cortical narrowing (CNO) in reverse shoulder arthroplasty. This study aimed to compare the incidence of CNO with different fixation methods (cemented or cementless) using a single implant (trabecular metal humeral stem) evaluated using tomosynthesis and to analyze the factors affecting the incidence of CNO for cementless stem fixation.

A total of 109 patients (cementless: 75 cases; cemented: 34 cases) who underwent reverse total shoulder arthroplasty were included in this study. The patients were divided into 2 groups (cementless or cemented), and the incidence of CNO was compared. In addition, patients in the cementless group were divided into 2 groups (canal filling ratio [CFR] of ≥ 0.7 or < 0.7), the incidence of CNO was compared, and the Cramer's coefficient of association between CNO and CFR > 0.7 (and 0.8) was calculated.

No significant difference was observed in the incidence of CNO between the cementless and cemented groups (7/75 vs. 3/35, P value = 1.0). The association between CNO and the CFR using Cramer's coefficient of association showed that there were few correlations (coefficient: 0.14, P value = .59).

Cementless reverse total shoulder arthroplasty with a trabecular metal stem has a similar low incidence of CNO as cemented fixation, and the incidence of CNO with a trabecular metal stem was lower than that reported in previous studies. A CFR > 0.7 was not associated with the incidence of CNO.

Humeral-sided complications account for up to 21% of all revision reverse total shoulder arthroplasty (RTSA) surgeries. Stress shielding with large bulky stems can lead to proximal bone resorption per Wolff law, complicating further surgeries. Previously published studies suggest that lowering the metaphyseal implant fill ratio can lead to fewer adaptive radiographic changes and decreased bone resorption. Inspired by these studies, cementless primary RTSA implantation technique with humeral matchstick autografts was proposed to augment cementless humeral constructs, foster the use of a smaller size stem, and create primary stability of the humeral implant even in osteoporotic or in-between size medullary canals. In this study, retrospective review of this cementless RTSA technique with short-term radiographic evaluation was performed.

Forty-six nonconsecutive patients underwent primary RTSA with a short-stem cementless prosthesis (Stryker Ascend Flex) augmented by matchstick bone grafting from January to July 2020. Patient demographics were recorded, and follow-up radiographs were retrospectively reviewed to assess metaphyseal fill ratios and incidence of stress shielding at minimum 1-year follow-up. Discrepancies between templated and final stem sizes were recorded, along with all intraoperative and postoperative complications.

Of the 46 patients originally identified, there were 5 men and 41 women with a mean age of 71 years (standard deviation [SD] 7, range 53-88). Mean templated stem size was 4 (SD 2, range 1-8), whereas the mean final implant size was 2 (SD 1, range 1-3). Mean fill ratios were 0.76 (SD 0.06, range 0.54-0.89) along the metaphysis and 0.67 (SD 0.09, range 0.49-0.83) along the diaphysis. There were no intraoperative humeral fractures from implantation. All patients were available for radiographic follow-up with a mean of 19 months (SD 8, range 12-40). There were 3 cases (7%) of proximal humeral stress shielding, with average fill ratios of 0.857 and 0.807 in the metaphysis and diaphysis, respectively. There were 3 patients (7%) who underwent revision surgeries for baseplate failure and periprosthetic humeral fracture. There were no cases of early humeral loosening.

Matchstick autograft humeral augmentation is a simple, promising surgical technique with low intraoperative complication rates and good short-term radiographic outcomes. When the implant fill ratio is successfully reduced, there is a possible lower risk of humeral stress shielding. The authors believe this technique can help maximize implant stability in cementless shoulder arthroplasty and preserve humeral bone stock for future revision surgeries.

Several studies have reported proximal bone resorption in stemless and press-fit short-stem humeral implants for anatomic total shoulder arthroplasty. The purpose of this biomechanical study was to evaluate implant and cortical bone micromotion of a cortical rim-supported stemless implant compared to a press-fit short stem implant during cyclic loading and static compression testing.

Thirty cadaveric humeri were assigned to 3 groups based on a previously performed density analysis, adopting the metaphyseal and epiphyseal and inferior supporting bone densities for multivariate analyses. Implant fixation was performed in stemless implant in low bone density (SL-L, n = 10) or short stem implant in low bone density (Stem-L, n = 10) and in stemless implant in high bone density (SL-H, n = 10). Cyclic loading with 220 N, 520 N, and 820 N over 1000 cycles at 1.5 Hz was performed with a constant valley load of 25 N. Optical recording allowed for spatial implant tracking and quantification of cortical bone deformations in the medial calcar bone region. Implant micromotion was measured as rotational and translational displacement. Load-to-failure testing was performed at a rate of 1.5 mm/s with ultimate load and stiffness measured.

The SL-H group demonstrated significantly reduced implant micromotion compared to both low-density groups (SL-L: P = .014; Stem-L: P = .031). The Stem-L group showed significantly reduced rotational motion and variance in the test results at the 820-N load level compared to the SL-L group (equal variance: P = .012). Implant micromotion and reversible bone deformation were significantly affected by increasing load (P < .001), metaphyseal cancellous (P = .023, P = .013), and inferior supporting bone density (P = .016, P = .023). Absolute cortical bone deformation was significantly increased with stemless implants in lower densities and percentage reversible bone deformation was significantly higher for the SL-H group (21 ± 7%) compared to the Stem-L group (12 ± 6%, P = .017).

A cortical rim-supported stemless implant maintained proximally improved dynamic bone loading in variable bone densities compared to a press-fit short stem implant. Biomechanical time-zero implant micromotion in lower bone densities was comparable between short stem and stemless implants at rehabilitation load levels (220 N, 520 N), but with higher cyclic stability and reduced variability for stemmed implantation at daily peak loads (820 N).

Reproducible methods for determining adequate bone densities for stemless anatomic total shoulder arthroplasty (aTSA) are currently lacking. The purpose of this study was to evaluate the utility of preoperative computed tomography (CT) imaging for assessing the bone density of the proximal humerus for supportive differentiation in the decision making for stemless humeral component implantation. It was hypothesized that preoperative 3-dimensional (3-D) CT bone density measures provide objective classifications of the bone quality for stemless aTSA.

A 3-part study was performed that included the analysis of cadaveric humerus CT scans followed by retrospective application to a clinical cohort and classification with a machine learning model. Thirty cadaveric humeri were evaluated with clinical CT and micro-CT (μCT) imaging. Phantom-calibrated CT data were used to extract 3-D regions of interest and defined radiographic scores. The final image processing script was applied retrospectively to a clinical cohort (n = 150) that had a preoperative CT and intraoperative bone density assessment using the "thumb test," followed by placement of an anatomic stemmed or stemless humeral component. Postscan patient-specific calibration was used to improve the functionality and accuracy of the density analysis. A machine learning model (Support vector machine [SVM]) was utilized to improve the classification of bone densities for a stemless humeral component.

The image processing of clinical CT images demonstrated good to excellent accuracy for cylindrical cancellous bone densities (metaphysis [ICC = 0.986] and epiphysis [ICC = 0.883]). Patient-specific internal calibration significantly reduced biases and unwanted variance compared with standard HU CT scans (P < .0001). The SVM showed optimized prediction accuracy compared with conventional statistics with an accuracy of 73.9% and an AUC of 0.83 based on the intraoperative decision of the surgeon. The SVM model based on density clusters increased the accuracy of the bone quality classification to 87.3% with an AUC of 0.93.

Preoperative CT imaging allows accurate evaluation of the bone densities in the proximal humerus. Three-dimensional regions of interest, rescaling using patient-specific calibration, and a machine learning model resulted in good to excellent prediction for objective bone quality classification. This approach may provide an objective tool extending preoperative selection criteria for stemless humeral component implantation.

Aseptic humeral stem loosening is an uncommon complication of shoulder arthroplasty, and its presence has been considered a highly specific predictor of prosthetic joint infection (PJI). Literature on aseptic humeral stem loosening is sparse. The primary purpose of this study was to determine the rate of aseptic humeral loosening in revision shoulder arthroplasty. Secondarily, we sought to identify predictors of septic and aseptic humeral loosening.

Our institutional revision shoulder arthroplasty database was reviewed. Inclusion criteria were patients with humeral stem loosening as indicated in the operative report. Patient demographics, index surgery and indication, revision surgery and indication, and operative data were recorded. Charts were manually reviewed, and PJI scores were calculated using the International Consensus Meeting scoring criteria. International Consensus Meeting classifications of PJI "unlikely" and "possible" were considered aseptic, and PJI "probable" and "definite" were considered septic. Statistical analysis was performed to determine associations between the abovementioned variables and aseptic humeral loosening.

Forty-six patients with 48 shoulders were included in our analysis. Ten cases (21%) were classified as definite PJI, 13 cases (27%) were classified as probable PJI, 4 cases (8%) were classified as possible PJI, and 21 cases (44%) were classified as PJI unlikely. On analysis of stem design, there were no statistically significant associations with aseptic loosening; although, a lack of proximal porous ingrowth surface trended toward higher rates of aseptic loosening in all patients and in anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA) subgroup analyses. In the index RTSA subgroup, aseptic loosening was associated with female sex (P = .005). Seventeen of 39 shoulders (44%) that underwent either index ATSA or RTSA demonstrated concomitant glenoid loosening. The absence of glenoid loosening was associated with aseptic humeral loosening in index ATSA and RTSA (P < .001).

Fifty-two % of revision shoulder arthroplasty cases with humeral loosening performed at our institution were aseptic. There appear to be distinct demographic and radiographic factors that are more commonly associated with aseptic as opposed to septic humeral loosening. Our data demonstrate that demographic predictors of aseptic loosening of RTSA include female sex. The absence of glenoid component loosening is associated with aseptic humeral loosening and concomitant glenoid loosening is associated with septic humeral loosening. Understanding of these factors can guide the preoperative index of suspicion for PJI in the setting of humeral stem loosening.

The purposes of this study were to analyze and compare the functional outcomes and radiological changes around the press-fit humeral components in two contemporary medialized reverse total shoulder arthroplasty (RTSA) systems at a minimum of 5-year follow-up.

Between December 2003 and December 2015, 249 consecutive RTSAs were performed at our hospital. Of these, 68 primary uncemented RTSA met our inclusion criteria. The Constant-Murley score (CMS), the modified Constant score, a visual analog scale (VAS) and active shoulder range of motion (ROM) were measured pre- and postoperatively. Radiological assessment was performed by plain radiographs at a minimum of 5 years postoperatively.

At a mean follow-up of 80.2 months, there was no significant difference (p = .59) between the postoperative functional scores and range of motion of the two groups (Delta Xtend and Lima SMR). Radiological data of stress-shielding were observed in 38 patients (55.9%) being slightly more frequent in the Lima SMR group (21 patients) than in the Delta Xtend group (17 patients) (p = .62).

Our study shows that the good functional results are similar between the two uncemented RTSA systems used and that they do not depend on the presence of radiological changes (stress-shielding) in the humeral stem at a minimum 5-year follow-up.

The design of humeral implants has evolved from the initial Grammont design, notably regarding the neck-shaft angle (NSA) and through the use of cementless prostheses. Stress shielding was frequently reported with cementless implants, the 2 main risk factors being humeral stem misalignment and high filling ratios. Our hypothesis was that standard length cementless stems with an NSA of 140° would facilitate good alignment with moderate filling ratios, thereby limiting stress shielding and ensuring good clinical outcomes.

A single-center retrospective study was conducted of patients who underwent reverse total shoulder arthroplasty between January 2015 and August 2017, with at least 2 years' follow-up. Clinical evaluations included range of motion measurements and Constant and subjective shoulder values scores. Frontal alignment was assessed in terms of the angle (α) between axes of the stem and of the humerus. Filling ratios were measured in the metaphysis of the humerus, in the diaphysis, and at the distal end of the stem and considered excessive above 0.7. Stress shielding was evidenced radiographically by the observation of medial cortical narrowing, medial metaphysis thinning, lateral metaphysis thinning or under-the-baseplate osteolysis.

Eighty-two shoulders were included and 70 had radiographic follow-up data available. The mean patient age was 78 years and 63/81 patients (78%) were female. The mean follow-up time was 39 ± 7 months. The mean α angle was 1.4° ± 0.9° and was less than 5° in all cases. The mean metaphyseal, diaphyseal, and distal filling ratios were 0.61 ± 0.06, 0.70 ± 0.08, and 0.64 ± 0.09, respectively. The mean Constant score improved from 28 ± 11 preoperatively to 64 ± 14 at last follow-up. The mean subjective shoulder values score at last follow-up was 81 ± 12. Seventy-nine percent of patients (55/70) had at least 1 form of stress-shielding related, which were not associated with clinical outcomes, apart from lateral metaphysis thinning, which was associated with lower active anterior elevation (mean, 106° ± 30° vs. 126° ± 28°; P = .01) and lower Constant scores (mean, 56 ± 17 vs. 65 ± 14; P = .06).

The use of cementless reverse shoulder prostheses with a NSA of 140° was associated with good clinical outcomes at 2 years' follow-up. The prosthesis stem was correctly aligned with the humeral axis and the filling ratios were <0.7 in all cases. Stress-shielding was common but, apart from lateral metaphysis thinning, this had no impact on clinical outcomes.

This multicenter retrospective study was conducted with the objective of comparing the outcomes and complications between inlay and onlay reverse shoulder arthroplasty (RSA) in patients presenting Neer Type 4 proximal humerus fractures and cuff tear arthropathy. The primary aim of this investigation was to assess and juxtapose the clinical as well as functional outcomes of individuals who underwent onlay reverse shoulder arthroplasty with those who underwent inlay reverse shoulder arthroplasty.

A retrospective cohort study was conducted, involving patients who had undergone reverse shoulder arthroplasty between the period of 2016 and 2022. The study divided the population into two groups: Group A received inlay humeral components, while Group B received onlay humeral components. Functional outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) and Constant scores. Range of motion, infection, periprosthetic fractures, and nerve injuries were also assessed.

The study included 67 patients in Group A and 62 patients in Group B. Group A had significantly better functional outcomes, as indicated by higher ASES and Constant scores (p < 0.05). Group A also had greater shoulder joint motion (p < 0.05). Periprosthetic fractures were significantly more common in Group B (p < 0.05). However, complication rates, including infection and instability, did not significantly differ between the groups (p > 0.05). Nerve injuries occurred in both groups, with slightly higher occurrence in Group B.

Inlay humeral components in reverse shoulder arthroplasty for Neer Type 4 fractures and cuff tear arthropathy resulted in better functional outcomes, increased range of motion, and lower incidence of periprosthetic fractures compared to onlay components. Onlay components showed potential advantages in reducing instability rates. Further studies with larger samples and standardized protocols are needed to confirm these findings.

This study aims to determine the stress shielding and other radiological outcomes of patients who underwent an uncemented reverse shoulder arthroplasty (RSA) with an anatomic proximal coated stem for complex proximal humeral fractures (PHF) with 3 or 4 parts at 2 years postoperatively.

37 shoulders underwent an uncemented RSA for PHF from November 2015 to February 2019 and were followed up for 2 years. A radiographic assessment of stress shielding, filling ratio, stem stability (radiolucent lines/subsidence/alignment), tuberosity healing and notch was performed.

The mean age at the time of surgery was 72 years (range, 61-85). Stress shielding was appreciated in 31 shoulders (83.8%). The most important characteristic of stress shielding is cortical resorption: Grade 3 resorption occurred in 3 shoulders (8.1%) and grade 4 in 23 (62.2%) as per the grading system defined by Inoue et al. (Inoue et al. in J Shoulder Elbow Surg 26:1984-1989, 2017). A high occurrence of bone resorption was observed in Gruen zones 2 (Lateral Stress shielding) and 7 (Medial Stress shielding). The mean distal filling ratio in patients without stress shielding was 78,48(SD 14,9), whereas in patients with stress shielding, it was slightly higher with a mean of 81,68% (SD 4,89). Tuberosity healing was found in 94.6% (35/37) of the shoulders. No patient had any radiolucent line. No notch was observed.

At short-term follow-up, a high rate of tuberosity healing was achieved (94.6%) even though stress shielding was found in 83.8% (31/37) of the shoulders. Bone resorption was most frequently observed externally at zone 2 (Lateral stress shielding) and internally at zone 7 (Medial stress shielding). A higher filling ratio was associated with an increased occurrence of stress shielding. The uncemented anatomic humeral component did not result in early loosening.

IV; Case Series; Treatment study.

Newer generation humeral stem designs in total shoulder arthroplasty (TSA) are trending towards shorter lengths and uncemented fixation. The goal of this study is to report a 2-yr minimum clinical and radiographic outcomes of an uncemented short-stem press-fit humeral stem in anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA).

A retrospective multicenter database review was performed of all patients who received an uncemented short-length press-fit humeral stem (Equinoxe Preserve humeral stem, Exactech, Inc., Gainesville, FL, USA) in ATSA and RTSA with a minimum two-year follow-up. The primary outcome was the prevalence of humeral stems at risk of radiographic loosening. Secondary outcomes included evaluation of functional outcome scores and prevalence of revision TSA for humeral stem loosening. Two blinded observers performed radiographic analyses, which included humeral stem alignment, canal filling ratio, radiolucent lines, stress shielding (calcar and greater tuberosity), and changes in component position (subsidence and stem shift). At risk stems were defined by the presence of one or more of the following: humeral stem with shifting or subsidence, scalloping of the humeral cortex, or radiolucent lines measuring 2 mm or greater in 3 or more zones.

287 patients (97 ATSA and 190 RTSA) were included in this study. The mean follow-up was 35.9 (±6.1) months. There were significant improvements for all functional outcome scores (P < .05), range of motion (P < .05), and visual analogue pain scale pain (P < .05). The prevalence of humeral stem at risk of radiographic loosening was 1% in the ATSA group (1/97) and 18.4% in the RTSA group (35/190). Calcar resorption was seen in 34% of ATSA and 19% of RTSA, with severe resorption in 12.4% of ATSA and only 3.2% of RTSA. Greater tuberosity resorption was present in 3.1% of ATSA and 7.9% of RTSA. The mean canal filling ratio was 50.2% (standard deviation 11.2%). Using logistic regression, a significant positive correlation between canal filling ratio and stress shielding (P < .01) was seen for both calcar and tuberosity stress shielding. The revision surgery rate was 0% in ATSA compared to 1.6% in RTSA.

This retrospective study demonstrates a low revision rate and low prevalence of humeral stems at risk of radiographic loosening at two years with a press-fit short-stem humeral design in ATSA. Physiologic subsidence of humeral stems can account for higher prevalence of humeral stems at radiographic risk of loosening in RTSA compared to ATSA.

Use of standard-length anatomic total shoulder (TSA) humeral stems has been associated with high rates of medial calcar bone loss. Calcar bone loss has been attributed to stress shielding, debris-induced osteolysis, and undiagnosed infection. Short stem and canal-sparing humeral components may provide more optimal stress distribution and thus lower rates of calcar bone loss related to stress shielding. The purpose of this study is to determine whether implant length will affect the rate and severity of medial calcar resorption.

A retrospective review was performed on TSA patients treated with three different-length humeral implants (canal-sparing, short, and standard-length designs). Patients were matched 1:1:1 based on both gender and age (±4 years), resulting in 40 patients per cohort. Radiographic changes in medial calcar bone were evaluated and graded on a 4-point scale, from the initial postoperative radiographs to those at 3 months, 6 months, and 12 months.

The presence of any degree of medial calcar resorption demonstrated an overall rate of 73.3% at one year. At 3 months, calcar resorption was observed in 20% of the canal-sparing cohort, while the short and standard designs demonstrated resorption in 55% and 52.5%, respectively (P = .002). At 12 months, calcar resorption was seen in 65% of the canal-sparing design, while both the short and standard designs had a 77.5% rate of resorption (P = .345). The severity of calcar resorption for the canal-sparing cohort was significantly lower at all time points when compared to the short stem (3 months, P = .004; 6 months, P = .003; 12 months, P = .004) and at 3 months when compared to the standard-length stem (P = .009).

Patients treated with canal-sparing TSA humeral components have significantly lower rates of early calcar resorption with less severe bone loss when compared to patients treated using short and standard-length designs.

Shoulder arthroplasty humeral stem design has evolved to include various shapes, coatings, lengths, sizes, and fixation methods. While necessary to accommodate patient anatomy characteristics, this creates a surgical paradox of choice. The relationship between the surgeon's selection of short-stem implant size and construct stiffness, resistance to subsidence and micromotion has not been assessed.

Eight paired cadaveric humeri were reconstructed with surgeon-selected (SS) and 2-mm diametrically larger (SS+2) short-stemmed press-fit implants. Each reconstruction was subjected to 2000 cycles of 90° forward flexion loading, and stem subsidence and micromotion were measured using optical tracking. Compressive stiffness of the stem-bone reconstruction was then assessed by applying a load in-line with the stem axis that resulted in 5 mm of stem subsidence.

Increasing stem size by 2 mm resulted in the construct stiffness more than doubling compared to SS stems (-741 ± 243 N/mm vs. -334 ± 120 N/mm; P = .003; power = 0.971). These larger stems also subsided significantly less than their SS counterparts (SS: 1.2 ± 0.6 mm; SS+2: 0.5 ± 0.5 mm; P = .029; power = 0.66), though there were no significant changes in micromotion (SS: 169 ± 59 μm; SS+2: 187 ± 52 μm; P = .506; power = 0.094).

The results of this study highlight the importance of proper short-stem sizing, as a relatively small 2 mm increase in diametral size was observed to significantly impact construct stiffness, which could increase the risk of stress shielding and implant loosening. Future work should focus on developing tools that objectively quantify bone quality and aid surgeons in selecting the appropriate size short-stem humeral implants for a particular patient.

The primary aim of this study was to assess the medium-term outcomes of the Global Icon stemless shoulder replacement in patients who have undergone primary total shoulder arthroplasty (TSA) for glenohumeral joint osteoarthritis. A retrospective review of patients who had undergone a TSA using the Global Icon stemless shoulder system was performed. The Western Ontario Osteoarthritis Shoulder (WOOS) Index and Oxford Shoulder Score (OSS) were evaluated pre-operatively and at 12 to 24 months post-operatively. Radiological outcomes, operation time, and post-operative complications were reported. Primary analysis for the WOOS Index and OSS focused on detecting within-group treatment effects at 24 months using a repeated measures ANOVA. Thirty patients were included in the study. Post-surgery, there was a significant improvement at 24 months on the OSS (ES = 0.932, CI: 41.7 to 47.7, p < 0.001) and the WOOS Index (ES = 0.906, CI: 71.9 to 99.8, p < 0.001). Radiographs revealed that no component loosened, migrated, or subsided. The median operative time was 75.5 (IQR: 12.25, range: 18 to 105) min. No implant-related complications were reported. The Global Icon stemless replacements have excellent clinical outcomes in this cohort at 12- and 24-month follow-up with no implant-related complications.

Anatomical total shoulder arthroplasty in its modern form where it reproduces the normal shoulder has been utilized clinically for more than half a century. As the technology and the designs have changed to recreate the humeral and glenoid sides of the joint, the sophistication of design has resulted in the growing number of cases annually worldwide. This increase is due in part to the increasing number of indications that the prosthesis can treat with successful results. On the humeral side, there have been design changes to better reflect the proximal humeral anatomy, and humeral stems are increasingly placed safely without cement. Platform systems which allow conversion of a failed arthroplasty to a reverse configuration without stem extraction is another design change. Similarly, there has been increasing utilization of short stem and stemless humeral components. Extensive experience with shorter stem and stemless devices, however, has yet to demonstrate the purported advantages of these devices, as recent studies have demonstrated equivalent blood loss, fracture rates, operative times, and outcome scores. Easier revision with these shorter stems remains to be definitively established, with only one study comparing the ease of revision between stem types. On the glenoid side, hybrid cementless glenoids, inlay glenoids, cementless all-polyethylene glenoids, and augmented glenoids have all been investigated; however, the indications for these devices remain unclear. Lastly, innovative surgical approaches to implanting shoulder arthroplasty and the use of patient specific guides and computerized planning, while interesting concepts, still await validation before they are utilized on a widespread basis. While reverse shoulder arthroplasty has been increasingly used to reconstruct the arthritic shoulder, anatomic glenohumeral replacement maintains a significant role in the armamentarium of the shoulder surgeon.

Onset of radial neck osteolysis (RNO) has been reported after radial head replacement (RHR), but data are sparse regarding impact and risk factors. We therefore conducted a retrospective study, 1) to quantify RNO after RHR, 2) to assess clinical and radiological impact, and 3) to identify risk factors.

RNO prevalence is high, but functional impact is limited.

A single-center retrospective study included all patients undergoing RHR for acute radial head fracture between 2008 and 2017: 53 patients, with a mean age of 53.8±15.7 years [range, 21-85 years]. At a minimum 2 years' follow-up, patients were assessed clinically on joint range of motion and Mayo Elbow Performance Score (MEPS) and radiologically on standard radiographs. Associations between RNO and various parameters were assessed.

At a mean 46.7±19.8 months' follow-up [range, 24-84 months], RNO was found in 54.7% of cases (29/53), with mean 4.0 ±2.8mm distal extension [range, 1.2-13.4mm], corresponding to 13.4±7.3% of stem height [range, 2.7-27.7%]. RNO at last follow-up was not significantly associated with reduced flexion-extension (121.9° versus 114.0°; p=0.11), pronation-supination (152.6° versus 138.3°; p=0.25) or MEPS (84.7 versus 84.8; p=0.97), or with higher rates of postoperative complications (11/29 (37.9%) versus 7/24 (29.2%); p=0.782) or surgical revision (11/29 (37.9%) versus 10/24 (41.7%); p=0.503). RNO was significantly associated with cementless fixation (19/29 (65.5%) versus 7/24 (29.2%); p=0.01), unipolar prosthesis (21/29 (72.4%) versus 7/24 (29.2%); p=0.002), high filling-ratio, whether proximal (88% versus 77%; p=0.002), middle (84% versus 75%; p=0.007) or distal (69% versus 59%; p=0.032), and shorter radial stem (33.2mm versus 46.3mm; p=0.011). No demographic parameters showed significant association with RNO at last follow-up.

RNO was frequent after RHR, but without clinical or radiological impact in the present series. The risk factors identified here argue for involvement of stress shielding.

IV, cohort study.

This study aims to evaluate restoration of anatomy following Total Shoulder Arthroplasty (TSA) with the Mathys Affinis Short prosthesis.

Over the last decade stemless shoulder arthroplasty has increased in popularity. One of the reported advantages of the stemless designs is the ability to restore anatomy following surgery. However, very few studies have evaluated restoration of anatomy following stemless shoulder arthroplasty.

The study included all patients who had undergone TSA using the Affinis Short (Mathys Ltd, Bettlach, Switzerland) prosthesis for primary osteoarthritis between 2010 and 2016. The mean follow up was 42.8 months (range 9.4 to 83.4 months). Pre and post-operative radiographs were assessed for Centre of Rotation (COR), Humeral Head Height (HHH), Humeral Head Diameter (HHD), Humeral Height (HH) and, Neck Shaft Angle (NSA) using the best fit circle method on PACS software. Measurements were scored and compared to assess the accuracy of the implant in restoring the native geometry, including the intraobserver variability. The same data was collected by another experienced observer to measure the interobserver variability.

The deviation of COR of the prosthesis from the anatomical centre was less than 3 mm in 58 cases (85%). Humeral head height and humeral head diameter showed a variation of less than 3 mm in 66 cases (97%) and 43 cases (63%) respectively. Humeral height followed a similar trend, with 62 cases (91.2%) showing a difference of less than 5 mm. The neck shaft angle showed a variation of more than 8 degrees in 38 cases (55%), and 29 cases (42.6%) had a postoperative angle of less than 130 degrees.

Overall, stemless total shoulder arthroplasty with the Affinis Short prosthesis allows excellent restoration of anatomy confirmed by most of the measured radiographic parameters. The variability in neck shaft angle might be due to differing surgical techniques, with some surgeons preferring a slightly vertical neck cut to protect the rotator cuff insertion.

Proximal humerus fractures are the third most frequent type of fracture in elderly patients. Nowadays, surgical treatment is indicated one third of the time, being the reverse shoulder prosthesis an option especially in complex comminuted patterns. In this study we analyzed the effects of a lateralized reverse prosthesis in tuberosity union and its relationship with the functional results.

Retrospective case study of patients with proximal humerus fractures treated with a lateralized design reverse shoulder prosthesis with one-year minimum follow-up. Tuberosity nonunion was defined as a radiological concept: absence of tuberosity, distance >1cm from the tuberosity fragment to the humeral shaft or tuberosity above the humeral tray. Subgroup analysis was performed, group 1 (n=16) tuberosity union vs. group 2 (n=19) tuberosity nonunion. Groups were compared with the following functional scores: Constant, American Shoulder and Elbow Surgeons and Subjective Shoulder Value.

A total of 35 patients were included in this study with a median age of 72.65 years. Postoperative radiographic analysis at one year after surgery revealed a tuberosity nonunion rate of 54%. Subgroup analysis revealed no statistically significant differences in terms of range of motion or functional scores. However, there were differences regarding the Patte sign (p=0.03) which was positive in a larger proportion of patients in the group with tuberosity nonunion.

Even though there was a large percentage of tuberosity nonunion with the use of a lateralized prosthesis design, patients obtained good results in a similar manner to those found in the union group in terms of range of motion, scores, and patient satisfaction.

Although there is a trend to manage failed anatomic total shoulder arthroplasties (aTSA) with revision to a reverse total shoulder arthroplasty, such revisions can be complicated by difficulties in baseplate fixation, instability, and acromial stress fractures. Some cases of failed aTSA may be safely revised to a hemiarthroplasty (HA). The objectives of this study were to report patient-reported outcomes after conversion from aTSA to HA and assess patient and shoulder characteristics associated with a successful outcome.

Patients who underwent revision from aTSA to HA between 2009 and 2018 were contacted. Patient demographics, surgical history, intraoperative findings, and microbiology results were collected. Patient-reported outcomes were collected with minimum 2-year follow-up. Preoperative radiographic characteristics were reviewed for component positioning and component loosening. Patients with a clinically significant improvement exceeding the minimal clinically important difference (MCID) of the Simple Shoulder Test (SST) were compared with those patients who did not improve past the MCID.

Twenty-nine patients underwent conversion from aTSA to HA with a mean follow-up of 4.5 ± 1.8 years. Intraoperative glenoid or humeral component loosening was found in all 29 patients. Pain improved in 25 of 30 patients (87%), and mean pain scores improved from 6.2 ± 2.3 to 3.1 ± 2.4 (P < .001). SST scores improved from 4.1 ± 3.1 to 7.3 ± 3.2 (P < .001), and 18 of 29 patients (62%) had improvement above the SST MCID threshold of 2.4. The mean American Shoulder and Elbow Surgeons score at the latest follow-up was 64 ± 19, and the Single Assessment Numeric Evaluation score was 65 ± 23. Twenty-two of 29 (76%) patients were satisfied with the procedure. Four patients (14%) required conversion to total shoulder arthroplasty-2 to anatomic and 2 to reverse. An additional 3 patients (10%) had a revision HA performed. No significant differences in patient or shoulder characteristics were found in those patients who improved greater than the MCID of the SST compared patients who improved less than the MCID of the SST. Fifty-nine percent of patients had ≥2 positive cultures with the same bacteria, and 82% of these were with Cutibacterium. Seven of 8 patients (88%) with a loose humeral component had ≥2 positive cultures with the same bacteria.

Component loosening is a common failure mode after aTSA. Revision to HA can improve pain and patient-reported outcomes in most patients.

Radiographic stress shielding is a common finding in uncemented convertible short-stem shoulder arthroplasty (UCSSSA). The distal filling ratio (DFR) has been described as a predictor for the occurrence of stress shielding. A DFR > 70% was mentioned as a risk factor for the occurrence of stress shielding for some UCSSSA. However, measurements were only performed on conventional radiographs and no validation exists for 3D automated planning tools.

DFR was manually measured on postoperative true ap radiographs of 76 shoulder arthroplasties using a standardized protocol and were compared to preoperative CT scans with an automated calculation of the DFR after virtual implantation of the stem.

The mean DFR measured on X-rays was 75.9% (SD = 8.7; 95% CI = 74-78) vs. 78.9% (SD = 9.1; 95% CI = 76.8-83) automatically measured on CT scans. This difference was significant (p < 0.001). In 7 out of 76 cases (9%) the difference between manual measurement on radiographs and computerized measurement on CT scans was > 10%.

Manual measurement of the DFR is underestimated on conventional radiographs compared to automated calculation on CT scans be a mean of 3%. Therefore, automated measurement of the DFR on CT scans seems to be beneficial, especially in cases with osteopenic cortices. Manual measurement of the DFR on conventional ap radiographs in cases without CT scans, however, is still a viable alternative.

Level IV, retrospective study.

The successive refinement in implant design and operative technique alongwith improved understanding has resulted in increased incidence of total shoulder arthroplasty (TSA). Simultaneously, the indications of TSA have widened and include a range of shoulder pathologies.

Using the keywords and relevant literature, we have described an overview of the different stem sizes used in shoulder arthroplasty. Relevant description of clinical and radiological outcome is done with regards to different stem sizes.

There are plethora of shoulder replacement systems, based on unique philosophy and having their own advantages and disadvantages. Additionally, the rise in ageing population had increased the need for revision TSA, thereby necessitating the judicious choice of implant at primary TSA. We further present the role of cemented and uncemented humeral stems and discuss the findings of finite element analysis. The choice of humeral stem size and use of cemented or uncemented stems have been reported to affect the clinical and radiological outcomes.

Although there is increased utilization of stemless humeral implants in anatomic total shoulder arthroplasty (TSA), there are inadequate objective metrics to evaluate bone quality sufficient for fixation. Our goals are to: (1) compare patient characteristics in patients who had plans for stemless TSA but received stemmed TSA due to intraoperative assessments and (2) propose threshold values of bone density, using the deltoid tuberosity index (DTI) and proximal humerus Hounsfield units (HU), on preoperative X-ray and computed tomography (CT) to allow for preoperative determination of adequate bone stock for stemless TSA.

This is an observational study conducted at an academic institution from 2019 to 2021, including consecutive primary TSAs templated to undergo stemless TSA based on 3-dimensional CT preoperative plans. Final implant selection was determined by intraoperative assessment of bone quality. Preoperative X-ray and CT images were assessed to obtain DTI and proximal humeral bone density in HU, respectively. A receiver operating characteristic curve was used to analyze the potential of preoperative X-ray and CT to classify patients as candidates for stemless TSA.

A total of 61 planned stemless TSAs were included, with 56 (91.8%) undergoing stemless TSA and 5 (8.2%) undergoing stemmed TSA after intraoperative assessment determined that the bone quality was inadequate for stemless fixation. There were no significant differences between the 2 groups in terms of gender (P = .640), body mass index (P = .296), and race (P = .580). The stem cohort was significantly older (mean age 69 ± 12 years vs. 59 ± 10 years, P = .029), had significantly lower DTI (1.45 ± 0.13 vs. 1.68 ± 0.18, P = .007), and had significantly less proximal humeral HU (-1.4 ± 17.7 vs. 78.8 ± 52.4, P = .001). The receiver operating characteristic curve for DTI had an area under the curve (AUC) of 0.86, and bone density in HU had an AUC of 0.98 in its ability to distinguish patients who underwent stemless TSA vs. short-stem TSA. A threshold cutoff of 1.41 for DTI resulted in a sensitivity of 98% and a specificity of 60%, and a cutoff value of 14.4 HU resulted in a sensitivity of 95% and a specificity of 100%.

Older age, lower DTI, and less proximal humeral bone density in HU were associated with the requirement to switch from stemless to short-stem humeral fixation in primary TSA. Preoperative DTI had good ability (AUC of 0.86) and preoperative HU had excellent ability (AUC of 0.98) to categorize patients as appropriate for stemless TSA. This can help surgeons adequately plan humeral fixation using standard preoperative imaging data.

Uncemented reverse total shoulder arthroplasty (RTSA) for the primary treatment of proximal humerus fractures (PHF) in elderly patients was introduced at our institution in 2017. Recent reports have raised concerns about increased rates of early bone resorption at the proximal humerus with uncemented fracture stems. The aim of this study was to find out whether there was any difference in functional or radiographic outcomes between cemented and uncemented RTSA for PHF.

Seventeen consecutive patients who underwent uncemented RTSA (group nC) in 2017 and 2018 were age and sex matched (propensity score matching 1:2) to 34 patients with cemented RTSA implanted between 2011 and 2016 (group C) for the primary treatment of PHF. These two groups were compared in terms of clinical and radiographic outcomes at 2 years after the index surgery.

The mean bone quality was low in both groups: in group nC the deltoid tuberosity index (DTI) was 1.43 (1.22-1.72) and in group C 1.42 (1.22-1.67). At the final 2 year follow-up, the relative CS was 98.3% (71-118) in group nC and 97.9% (36-125) in group C (p = 0.927); the absolute CS was 70.2 (49-89) in group nC and 68.0 (30-94) in group C (p = 0.509). Lucent lines at the humeral site were seen in 8 cases (47%) in group nC and in 13 cases (38%) in group C (p = 0.056). Compared to 3% in group C, all patients in group nC showed at least grade 1 and 65% showed grade 3 bone resorption at the proximal humerus (p < 0.001).

Compared to cemented RTSA bone resorption at the proximal humerus was significantly more frequent in patients with uncemented RTSA for PHF. So far, this is rather a radiographic than a clinical finding, because both groups showed very satisfying functional outcomes and low revision rates at the 2 year follow-up.

A retrospective case-control study.

The employment of reverse shoulder arthroplasty for dislocated proximal humerus fractures of elderly patients becomes increasingly relevant. The standard inclination angle of the humeral component was 155°. Lately, there is a trend towards smaller inclination angles of 145° or 135°. Additionally, there has been an increased focus on the lateralization of the glenosphere. This retrospective comparative study evaluates clinical and radiological results of patients treated for proximal humerus fractures by reverse shoulder arthroplasty with different inclination angles of the humeral component, which was either 135° or 155°. Additionally, a different lateral offset of the glenosphere, which was either 0 mm or 4 mm, was used.

For this retrospective comparative analysis, 58 out of 66 patients treated by reverse total shoulder arthroplasty for proximal humerus fractures were included. The minimum follow-up was 24 months. Thirty (m = 3, f = 27; mean age 78 years; mean FU 35 months, range 24-58 months) were treated with a standard 155° humeral component and a glenosphere without lateral offset (group A), while 28 patients (m = 2, f = 26; mean age 79 years; mean FU 30 months, range 24-46 months) were treated with a 135° humeral component and a glenosphere with a 4 mm lateral offset (group B). We determined range of motion, Constant score, and the American Shoulder and Elbow Surgeons Shoulder score as clinical outcomes and evaluated tuberosity healing as well as scapula notching.

Neither forward flexion (A = 128°, B = 121°; p = 0.710) nor abduction (A = 111°, B = 106°; p = 0.327) revealed differences between the groups. The mean Constant Score rated 63 in group A, while it was 61 in group B (p = 0.350). There were no differences of the ASES Score between the groups (A = 74, B = 72; p = 0.270). There was an increased risk for scapula notching in group A (47%) in comparison to group B (4%, p = 0.001). Healing of the greater tuberosity was achieved in 57% of group A and in 75% of group B (p = 0.142). The healing rate of the lesser tuberosity measured 33% in group A and 71% in group B (p = 0.004).

Both inclination angles of the humeral component are feasible options for the treatment of proximal humerus fractures in elderly patients. Neither the inclination angle nor the lateral offset of the glenosphere seem to have a relevant influence on the clinical outcome. The healing rate of the lesser tuberosity was higher in implants with a decreased neck-shaft angle. There is an increased risk for scapula notching, if a higher inclination angle of the humeral component is chosen.

III. Retrospective comparative study.

Proximal humerus fractures are the third most frequent type of fracture in elderly patients. Nowadays, surgical treatment is indicated one third of the time, being the reverse shoulder prosthesis an option especially in complex comminuted patterns. In this study we analyzed the effects of a lateralized reverse prosthesis in tuberosity union and its relationship with the functional results.

Retrospective case study of patients with proximal humerus fractures treated with a lateralized design reverse shoulder prosthesis with one-year minimum follow-up. Tuberosity nonunion was defined as a radiological concept: absence of tuberosity, distance>1cm from the tuberosity fragment to the humeral shaft or tuberosity above the humeral tray. Subgroup analysis was performed, group 1 (n=16) tuberosity union vs. group 2 (n=19) tuberosity nonunion. Groups were compared with the following functional scores: Constant, American Shoulder and Elbow Surgeons and Subjective Shoulder Value.

A total of 35 patients were included in this study with a median age of 72.65 years. Postoperative radiographic analysis at one year after surgery revealed a tuberosity nonunion rate of 54%. Subgroup analysis revealed no statistically significant differences in terms of range of motion or functional scores. However, there were differences regarding the Patte sign (p=0.03) which was positive in a larger proportion of patients in the group with tuberosity nonunion.

Even though there was a large percentage of tuberosity nonunion with the use of a lateralized prosthesis design, patients obtained good results in a similar manner to those found in the union group in terms of range of motion, scores, and patient satisfaction.

Both stemmed and stemless designs for total shoulder arthroplasty (TSA) have demonstrated efficacious outcomes for the surgical treatment of primary glenohumeral joint osteoarthritis. The purpose of this systematic review and meta-analysis was to compare the clinical outcomes of stemmed versus stemless TSA in randomized controlled trials. We hypothesized that there would be no differences in Constant Score (CS), range of motion, or adverse events, such as periprosthetic fracture and/or revision surgery.

Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review of the literature was done using MEDLINE, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Registry of Controlled Trials, Embase, and Web of Science databases. Outcomes of interest included CS, range of motion, and adverse events (periprosthetic fracture and revision). Summary effect estimates of the mean difference between stemmed and stemless TSA for each outcome were estimated in random effects models.

The search yielded 301 articles with 4 appropriate for qualitative analysis, including the results of 229 stemmed and 358 stemless TSAs. No significant difference was observed in postoperative CS (P = 0.36), forward flexion (P = 0.93), abduction (P = 0.30), or external rotation (P = 0.34) between stemmed and stemless TSA. No significant difference was observed in change in CS (P = 0.27), forward flexion (P = 0.25), or external rotation (P = 0.74). A change in abduction was significantly different between stemmed and stemless TSA (standardized mean difference = -0.64; 95% confidence interval, -1.20 to -0.08) in favor of stemmed TSA (P = 0.02), attributed to preoperative differences. No significant difference was observed in periprosthetic fractures (P = 0.07) or revision (P = 0.90).

TSA with stemless versus stemmed humeral components was not associated with notable differences in functional and clinical outcomes. No difference was observed between stemmed and stemless designs in postoperative forward flexion, abduction, or external rotation. Similarly, there was no difference in change in forward flexion or external rotation. A markedly greater improvement in abduction was observed with stemmed TSA, likely due to the lower preoperative motion in the stemmed cohort in one of the studies. No differences were observed between stemmed and stemless designs in the rate of humeral fracture or risk of revision.

Level II; systematic review and meta-analysis of prospective randomized controlled trials.

Stemless shoulder arthroplasty using 4 open-fin press-fit anchors has been showing promising short-term clinical and radiographic results for patients' primary osteoarthritis. This prospective, multicenter study presents 5-year postoperative clinical and radiological outcomes of a stemless shoulder arthroplasty for primary osteoarthritis.

Between November 2012 and December 2015, 100 patients were treated for primary osteoarthritis with the Sidus stem-free shoulder system at 7 European centers. Clinical assessment included the Constant-Murley Score, American Shoulder and Elbow Standardized Shoulder Assessment Form score, Subjective Shoulder Value, and range of motion. True anteroposterior, axial and lateral radiographs were reviewed for osteolysis, glenoid and humerus loosening, heterotopic ossification, radiolucent lines, component migration and humeral bone resorption. In addition to a Kaplan-Meier survival analysis, a comparative analysis between total shoulder arthroplasty and hemiarthroplasty was performed.

Seventy-one patients (36 females) with a mean age of 63.8 years (range: 47-79 years) were available for the 5-year clinical and radiographic follow-up (range: 52-79 months). There was a significant increase (P < .0001) in all outcome scores compared to baseline values. Patients with total shoulder arthroplasty (n = 48) achieved significantly better functional outcome than patients with shoulder hemiarthroplasty (n = 23) with regard to the absolute and relative Constant-Murley Score, American Shoulder and Elbow Standardized Shoulder Assessment Form score, and Subjective Shoulder Value as well as greater abduction strength and range of motion in forward elevation and external rotation (P ≤ .004). There were no cases of osteolysis or humeral loosening. There were some cases of heterotopic ossification (1.4%), radiolucency around the humerus (1.4%) or glenoid (25%), glenoid migration (2.1%), inferior osteophytes (1.4%) or humerus bone resorption (9.9%). The 5-year survival was 94%.

Patients treated with the Sidus stem-free shoulder system for primary osteoarthritis continue to achieve good clinical and radiographic results without any signs of aseptic humeral implant loosening at 5 years postsurgery.

Proximal humeral bone loss in total shoulder arthroplasty (TSA) is more frequent than in hemiarthroplasty. Factors such as age, gender, inclination angle, and radiolucent lines may also contribute. Additionally, current bone loss grading systems are often not sensitive enough to detect slight bone changes, especially at the medial calcar where bone loss is commonly observed. This study uses a new, more detailed bone loss grading system to evaluate factors that could influence bone loss at the proximal humerus.

In this single-center prospective study, patients underwent hemiarthroplasty or TSA with an anatomic stemless prosthesis. Bone loss was measured at the proximal humerus using the new grading system. The effect of treatment type, age, gender, radiolucent lines, and inclination angle on bone loss was evaluated. The Constant-Murley score of patients was assessed and complications recorded.

Ninety-one shoulders were available for the final follow-up examination at a median of 85.0 months (range 82.6-121.1 months). Bone loss was found at the proximal humerus in approximately one-third of shoulders, and significantly more shoulders had bone loss in TSA than in hemiarthroplasty (P = 0.03). However, this difference was no longer significant after stratifying by gender and age (P > 0.05). Bone loss significantly correlated with gender (P = 0.03) but not with treatment type, radiolucent lines, and the postoperative inclination angle (P > 0.05). Most Constant-Murley score components did not differ significantly between shoulders with and without bone loss (P > 0.05). Lastly, six complications and four revisions were reported.

Results showed gender had the greatest influence on bone loss after stemless shoulder arthroplasty. Furthermore, both patients with or without bone loss can expect similar clinical outcomes with the stemless prosthesis used in this study. Lastly, the new grading system is simple and straightforward to use.

Although the use of short stem and stemless shoulder prosthesis is trending, the surgical outcome may vary due to varying biomechanics. Objectives were to evaluate and compare the short-term clinical results and radiological changes between anatomical total shoulder arthroplasty (TSA) and reverse TSA (rTSA) with a short-stem humeral design.

There is no clinical and radiological difference between TSA and rTSA using a short-stem humeral design.

This retrospective study included 66 patients who underwent TSA and rTSA (33 patients each) with a minimum 2-year follow-up. Radiographic findings, including preoperative Tingart cortical index (TCI), postoperative filling ratios of metaphysis (FRmet) and diaphysis (FRdia), bone adaptations, and osteolysis around the humeral stem at the immediate postoperative period, and the most recent follow-up were measured. Pre and postoperative Constant-Murley score, subjective shoulder value (SSV), and complications were noted.

At a mean follow-up of 27 (range 24-50) months, FRmet was significantly higher in rTSA group than the TSA group (0.65 vs. 0.60, p=0.009). Bone resorption was similar in both groups (p=0.76) and was correlated to a lower TCI value of<2.9mm (p=0.02). Despite significant clinical improvement in individual groups, the comparison between groups was non-significant (p>0.05). Negative correlation was observed between TCI and total clinical score (p=0.045) in TSA group, active external rotation (p=0.019), activity (p=0.005), SSV (p=0.008) and total score (p=0.025) in rTSA group. Radiographic changes were not influenced by patient characteristics and clinical results (p>0.05).

Although no radiographic difference was observed between TSA and rTSA, better short-term clinical results observed with the usage of the short-stem humeral design prosthesis are encouraging.

III; Retrospective cohort study.

Periprosthetic osteolysis is a known complication after shoulder arthroplasty that may lead to implant loosening and revision surgery. To date, there is no consensus in the shoulder arthroplasty literature regarding the definition of osteolysis or the grading criteria, thus making it difficult to quantify and compare outcomes involving this complication. The purpose of this study was to perform a systematic review of the literature to assess how periprosthetic osteolysis in shoulder arthroplasty is defined and evaluated radiographically.

A systematic review of MEDLINE, Scopus, Cochrane, and CINAHL was performed in August 2021 for studies that provided a definition and/or grading criteria for osteolysis in shoulder arthroplasty. Only studies with a minimum of 2 years of radiographic follow-up were included.

Thirty-four articles met the inclusion criteria. After consolidating studies by the same primary author that included the same grading criteria, 29 studies were examined for their definition and grading criteria for osteolysis. Of these, 19 (65.5%) evaluated osteolysis surrounding the glenoid and 18 (62.1%) evaluated osteolysis surrounding the humerus. There was considerable heterogeneity in the systems used to grade periprosthetic osteolysis surrounding the glenoid, whereas humeral periprosthetic osteolysis was often categorized via visualization into binary or categorical groups (e.g., presence versus absence; mild, moderate, or severe; partial versus complete). Four studies (13.8%) provided novel measurements for assessing either glenoid or humeral osteolysis.

Considerable heterogeneity exists in the assessment and grading of periprosthetic osteolysis in shoulder arthroplasty. The most common grading systems were binary and used qualitative visual interpretation, making them relatively subjective and prone to bias. Quantitative measurements of osteolysis were infrequently utilized. A standardized method of assessing osteolysis would be of value to facilitate communication and research efforts.

The use of reverse total shoulder arthroplasty and stemless anatomic total shoulder replacement has been increasing in the United States every year. Stemless humeral components in reverse total shoulder arthroplasty are only approved for clinical trials in the United States with an investigational device exception with limited data.

A systematic review on stemless reverse total shoulder arthroplasty was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A search was conducted on November 25, 2020, using the MEDLINE/PubMed, Cochrane, and Embase databases. All articles were reviewed by 2 independent evaluators, with any conflicts or issues resolved by consensus or a final decision by the senior author. The primary outcomes extracted were complications, radiographic results, and outcome scores.

We evaluated 10 studies that used either the Total Evolutive Shoulder System (TESS) or Verso implant. There were 430 total patients and 437 total procedures; 266 patients in the TESS group underwent a total of 272 procedures, and 164 patients in the Verso group underwent a total of 165 procedures. The mean age at the time of surgery was 73.8 years (range, 38-93 years). The mean follow-up period ranged from 6.4 to 101.6 months per study. There was an overall trend of improved clinical outcome scores, a 0.2% humeral component loosening rate, and an 11.2% complication rate.

This review shows that the clinical and functional outcomes following stemless or metaphyseal reverse total shoulder arthroplasty are quite promising, especially with the low rate of humeral-sided complications. There continues to be a need for additional long-term studies and randomized clinical trials.

Some patients show severe humeral bone stress shielding even one year after press-fit humeral stem, which can be a risk factor for implant durability. This study compared humeral stress shielding and clinical outcomes between high and low filling ratio (HFR and LFR) stems in primary reverse shoulder arthroplasty (RSA).

From 2015 to 2020, 104 patients who underwent RSA with a non-cemented standard-length humeral stem were examined. The humeral stems included large press-fit stems (HFR group, 53 patients) or small non-press-fit stems with autogenous cancellous bone grafting (LFR group, 51 patients). The radiologic and clinical outcomes were compared between the groups one year post-operatively.

One patient in the LFR group with early infectious dislocation was excluded from the 1-one year evaluation. No stress shielding was observed in 27/50 (54.0%) and 5/53 (9.4%) of patients in the LFR and HFR groups, while 3/50 (6%) and 19/53 (35.8%) patients showed high-stress shielding, respectively. However, the stem alignment change, subsidence, complications and evidence of loosening did not differ between the groups. The final range-of-motion and functional scores were significantly poorer in the LFR group than those in the HFR group, although the difference was minimal.

Even at one year follow-up, patients receiving LFR stems with autogenous bone grafting had significantly less humeral stress shielding compared to patients with HFR stem with press-fit in primary RSA, without compromising stem stability.

The purposes of this study were to compare functional outcomes, radiographic stem changes and complication rate in patients with proximal humeral fractures operated with cemented or uncemented RSA.

Retrospective review of 68 primary RSAs in PHF, 45 cemented/23 uncemented. Functional outcomes were evaluated according to constant, ASES scales and the range of motion (ROM). Radiographic assessment was performed at a minimum of two years post-operatively.

The mean follow-up cemented/uncemented was 37.8/26.5 months (p = .04) and the mean age 78/80 years old (p = .09). The functional outcome and range of movement were equivalent in the two groups except for the forward flexion that was significantly higher in the cemented group (p = .03). Stress shielding was seen in 30.4% of uncemented group and none in the cemented. Anatomic tuberosity healing was significantly higher with uncemented components compared with cemented components (64% vs 91%, p = .02). Cemented stems had radiolucent lines with a width of 2 mm or more in three or more Gruen zones in 9% vs 0% in the uncemented group and an evident change in the stem position was present in 4% vs 0% in the non-cemented group.

At mid-term follow-up, no differences in functional outcomes were detected depending on the stem fixation technique. Cemented stems, however, have a complication rate (including stem loosening) significantly higher than press-fit stems.