Periprosthetic tibial fractures around a total knee replacement (TKR) remain challenging to manage, with little published information for guidance. The purpose of this study was to review the types, management techniques, and outcomes of periprosthetic tibial fractures in the largest series to date.

We identified 300 periprosthetic tibial fractures (285 patients) around a TKR (43% in primary TKRs and 57% in revision TKRs) sustained between 1996 and 2020. Fractures were classified according to Felix et al. as Type I (tibial plateau), Type II (adjacent to stem), Type III (distal to stem), or Type IV (tibial tubercle), with subtypes A (well-fixed component), B (loose component), and C (intraoperative fracture). Of the fractures in this study, 53% were Type I, 24% were Type II, 16% were Type III, and 8% were Type IV. A total of 46% of fractures occurred intraoperatively, and 54% of fractures occurred postoperatively (61% subtype A, 39% subtype B). The mean patient age at fracture was 67 years, and 64% of patients were female. The mean follow-up was 6 years.

The intraoperative fracture incidence was 1.40% in revision TKRs and 0.10% in primary TKRs. Among intraoperative fractures, the 2-year survivorship free from tibial component revision was highest in Type I (100%) and lowest in Type IV (67%) (p < 0.001). For postoperative fractures, the 2-year survivorship free from any reoperation was 29% and the 2-year survivorship free from tibial component revision was 51%. Type-I postoperative fractures had the lowest 2-year survivorship free from tibial component revision (10%), whereas Type-III fractures had the highest survivorship (88%) (p < 0.001).

Intraoperative periprosthetic fracture of the tibia was fourteenfold more likely in revision TKRs compared with primary TKRs. Among all intraoperative fractures, Type-I fractures were well-tolerated, with 100% survivorship free from tibial component revision at 2 years. Conversely, Type-I postoperative fractures had only 10% survivorship at 2 years.

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Unlike established knee phenotype classifications, the recently introduced Citak classifications describe the intrafemoral and intratibial knee morphology. The aim of this study was to evaluate the distribution of Citak types A, B and C of the distal femur and proximal tibia in a large cohort and to examine the influence of age, body mass index (BMI) and knee phenotypes.

A total of 8739 patients undergoing primary total knee arthroplasty (TKA) were included in this study. The coronal plane alignment of the knee (CPAK) and functional knee phenotypes were assessed on standardised preoperative long leg radiographs (LLR) using a validated artificial intelligence (AI) software. The Citak classification was measured manually, and BMI, sex and age were compared between the different Citak types.

The most common morphotypes were Citak type B of the distal femur (men: 1362 (46.5%); women 3042 (52.4%)) and Citak type C of the proximal tibia (men: 2605 (88.9%); women 5406 (93.0%)). Women with Citak type C of the distal femur (mean age 71.45a; p < 0.001) and proximal tibia (mean age 69a; p < 0.001) were significantly older, while no age differences were observed among men. Citak type A of the distal femur and proximal tibia had an overall higher BMI in both men and women.

The Citak types of the distal femur and the proximal tibia are age, sex and BMI dependent in patients undergoing primary TKA. Recognising these morphological variations might improve preoperative planning and implant selection in TKA, potentially improving patient outcomes. The Citak classification is useful to further characterise various knee morphotypes.

Level III.

In primary conventional TKA, the tibial fixation is achieved by the epiphyseal and metaphyseal zone. One of those two zones of fixation, can be compromised by the local bone quality (bone micro-architecture and resistance), previous surgery or decreased surface of contact, leading to micro-mobility of the implant and potentially leading to aseptic loosening (AL). It was our hypothesis that the addition of a short fully cemented stem would improve the metaphyseal and epiphyseal fixation of the implant. To verify this hypothesis, the goals of this retrospective study were therefore to compare if (1) The presence of a short, stubby stem will dissipate stress and decrease micro-mobility at the epiphyseal level resulting in less radiolucent lines around the tibial component. (2) Short stem primary TKA may improve survivorship of the implant in patients potentially at risk for aseptic loosening.

Retrospective cohort study of 326 patients operated with a morphometric implant between 2013 and 2018. A short stubby stem was added to the tibial implant, if at the time of the tibial cut, the surgeon judged the epiphyseal bone quality to be poor or a smaller tibial size was necessary. All primary TKA were radiographically evaluated. RLLs were recorded and described according to their radiological aspect, localization, time of appearance and their progression over time. Survivorship was compared in the 2 groups using the national joint registry.

71 TKAs out of 326 (22%) were stemmed. Of the 255 TKAs without stem, 53 (21%) showed RLLs under the tibial base plate and 1 case (0.4%) was revised for potential AL of the tibial implant. No RLLs were observed in the group of stemmed implants and no revisions for aseptic loosening were needed. Patients with stubby stems were elderly women with risk factors for osteoporosis or young men in need for correction of big coronal deformities.

A short stubby stem extension can reduce the rate of RLLs and AL in primary TKA, probably by adding metaphyseal fixation to the classic epiphyseal fixation of the tibia and by a reduction in micro- and macro-motion of the tibial component. Based on the results of our study, the addition of a short cemented stubby stem decreased the rate of RLL with no revision observed in the stemmed group during the study period. The used knee system allows this option. Intra-operative decision can be made easily when risk factors such as osteoporosis, female gender, big deformities, obesity can be identified.

III.

Distal femoral replacement (DFR) is a salvage option for massive femoral bone loss and is often performed in revision total knee arthroplasty (rTKA) that have undergone multiple prior procedures. This study aimed to report on a large cohort of DFRs performed at a tertiary referral institution regarding survivorship and risk factors for aseptic loosening, specifically the impact of a previously instrumented femoral canal.

Between 2016 and 2021, 105 patients undergoing rTKA to DFR with a minimum 2-year follow-up were identified. Kaplan-Meier estimates assessed survivorship free from all-cause reoperation, all-cause revision, and revision for aseptic loosening. Logistic regressions were conducted to assess potential risk factors for radiographic loosening and the need for revision.

Prior femoral canal instrumentation was identified in 59% of cases, and 54% had undergone multiple prior procedures. The 2-year survivorship free from revision for aseptic loosening was 93%. The 2-year survivorship free from all-cause reoperation was 87% for native canals and 59% for previously instrumented canals (P = 0.008). The 2-year survivorship free from all-cause revision was 100 and 81%, respectively (P = 0.014). Regression analysis found re-rTKA (odds ratio [OR] = 18.3, P = 0.006), prior femoral canal instrumentation (OR = 14.6, P = 0.01), and prior femoral canal cementation (OR = 8.2, P = 0.007) to be risk factors for aseptic loosening.

A DFR for rTKA had high 2-year survivorship free from revision for aseptic loosening (93%). Regression analyses revealed multiple risk factors for aseptic femoral component loosening with a previously instrumented femoral canal, resulting in a 2.8-times higher rate of reoperation, a 10.5-times higher rate of all-cause revision, and an 11-times higher rate of aseptic loosening. Future research on fixation strategies in sclerotic, previously instrumented femoral canals should be prioritized to reduce the risk of fixation failure in this high-risk cohort.

Metaphyseal sleeves (MS) achieve press-fit fixation in Zone 2 during revision total knee arthroplasty (rTKA). The canal filling ratio (CFR) estimates the engagement offered by a stem. The objectives in this study were to evaluate clinical and radiological outcomes in patients undergoing rTKA with stemmed MS and to determine if there is a correlation between these variables and stem length and CFR.

This retrospective study included 67 patients who underwent rTKA with uncemented stemmed MS, with a minimum follow-up of two years. The radiological outcomes included the stem length and CFR, the incidence of radiolucent lines for each sleeve, measured by the modified Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System for MS (mKSRESS), and limb alignment, measured by Hip-Knee-Ankle (HKA) angle. Functional outcomes comprised the Knee Society Score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Numerical Rating Score (NRS) for pain.

The mean CFR for femoral and tibial components was 64 ± 12 and 68.4 ± 12.1%, respectively. Radiolucencies were observed in 23.4% of femoral and 44.8% of tibial implants, with no cases of prosthetic loosening. The mean HKA was 178 ± 2.93º, with 94% of the patients within 3º varus-valgus. Patients who were correctly aligned had a significantly higher tibial CFR (69.2 versus 56.5%, respectively, P = 0.049) and stem length (97.7 versus 67.5 mm, respectively, P = 0.029). No correlation was found between CFR or stem length and mKSRESS. Functional outcomes improved significantly in all patients. Tibial CFR showed a weak, but significant correlation (r = 0.270) with KSS function (P = 0.031).

Press-fit stems may not be necessary to achieve adequate implant stability when used in combination with an MS, but tibial stem dimensions seem to influence limb alignment and could slightly improve functional outcomes.

Fixation in revision total knee arthroplasty(rTKA) should occur in at least 2 zones(epiphysis, metaphysis, or diaphysis) to maximize fixation strength. We report here the short-term survivorship of unsupported tibial base plates in rTKA when used with a cementless metaphyseal sleeve and non-cemented stem.

We retrospectively reviewed all patients undergoing rTKA between 2014 and 2021 by a single surgeon at a single institute. We identified 17 patients with a minimum follow-up of 1 year.

The average age at surgery was 66.4 years (range 50-80) and the average BMI was 34.6 (range 22.4-43.3). One patient had Type 1 and 16 patients had Type 2 bone loss preoperatively (Anderson Orthopaedic Research Institute classification). Two patients (11.8%) received a standard posterior stabilized insert, nine patients (52.9%) received a varus valgus constrained insert and the remaining 6 (35.3%) patients received a hinged implant. There were no cases of revision for loosening, fracture or mechanical failure of the tibial component construct at an average follow up of 2.9 years (maximum 7.9 years). One patient required revision for end of stem pain. Only 1 patient developed subsidence (≤ 3 mm) but did not have any clinical mechanical symptoms suggestive of loosening.

We report a 100% survivorship free of revision for loosening or mechanical failure of the tibial construct at short term follow up when using an unsupported tibial base plate with a metaphyseal sleeve and non-cemented stem. Based on early data, metaphyseal sleeves with a stable stem fixation in the tibia can be used without additional tibial tray fixation with cement.

➢ Bone defect management is challenging, but essential, in revision total knee arthroplasty.➢ Appropriate metaphyseal fixation is crucial for stability and implant support.➢ Allografts have been traditionally used to address large defects, but the advent of highly porous metaphyseal cones and sleeves has attracted attention during the past years.➢ Metaphyseal implants are now available in a variety of shapes and sizes to meet various clinical needs.➢ These devices can successfully fill large defects, can better support revision implants, and can achieve long-term biologic fixation.➢ Very good intermediate-term outcomes have been reported with the available metaphyseal implants, using fully cemented or press-fit stems.➢ More research is warranted to further assess surgical indications and the strengths and weaknesses of the various implants used for metaphyseal fixation.

The purpose of this study is to assess the short- and mid-term radiographic outcomes of a ream-then-broach metaphyseal cone design for revision total knee arthroplasty (rTKA).

A retrospective, multicenter analysis of rTKA patients utilizing femoral and/or tibial metaphyseal cone placement from January 2017 to July 2022 was performed. Assessment of radiolucency was performed utilizing a novel "cones score" for radiolucency for tibial and femoral cones.

Sixty-four rTKAs (23 femoral and 59 tibial cones) with short-term follow-up (12-24 months) and 80 rTKA (24 femoral and 76 tibial cones) with mid-term follow-up (>24 months) were assessed. No intraoperative complications were reported. No cases of cone or stem aseptic loosening were observed. The cones scoring system had a significantly strong intraclass correlation between the 3 reviewers (P < .001). Of tibial cones, 96.6% and 96.1% had no change in cones scoring at short- and mid-term follow-ups, respectively. Of femoral cones, 87.0% and 100% had no change in cones scoring at short- and mid-term follow-ups, respectively. All tibial and femoral implants were deemed radiographically stable at last radiographic follow-up.

The utilization of a ream-then-broach metaphyseal cones demonstrated excellent radiographic stability at short- and mid-term follow-ups. The use of this method has minimal risk of intraoperative or short-term failures. Surgeons should be familiar with this type of cone implantation system.

Effective management of bone defects is crucial in revision total knee arthroplasty (rTKA) to ensure implant stability in low-density bone environments, especially following prosthesis removal. While various reinforcement techniques exist, such as allografts, augments, metal cones, sleeves, or combinations thereof, metal cones are increasingly favored for their ability to reconstruct significant bone defects. A prominent challenge with off-the-shelf (OTS) cones is their unsuitability for Asian and specifically Iranian anatomies due to mismatched sizes and smaller medullary canals. This study explores the application of customized 3D-printed porous titanium cones, tailored to individual patient anatomy, for bone defect reconstruction in complex primary or revision total knee arthroplasty (TKA).

Utilizing CT scans for 3D preoperative planning, porous cones were individually designed to fit each patient's anatomy. A novel aspect of these cones is their dual functionality: promoting bone ingrowth while preventing cement infiltration. The cones were fabricated using selective laser melting with medical-grade Ti6Al4V alloy. To aid in surgical preparation, single-use polyamide trials were also 3D-printed.

A total of nineteen cones/half cones (four diaphyseal, twelve metaphyseal, and three meta-diaphyseal) for femoral and tibial applications were successfully designed and implanted across ten cases. There was a perfect alignment between preoperative planning and intraoperative outcomes, with precise defect reconstruction achieved in all cases. Early follow-ups indicated no loosening or implant migration.

Customized patient-specific porous cones offer not only the long-term benefits of OTS options, such as osseointegration and biological fixation but also accurately address a wide range of complex metaphyseal and diaphyseal defects. This approach preserves residual bone stock and streamlines the surgical process, presenting a promising advancement in bone defect management in rTKA.

Distal femoral replacement (DFR) with megaprostheses is a salvage revision total knee arthroplasty (rTKA) procedure indicated in cases with massive bone defects in the distal femur. As long as these implants achieve fixation only in the diaphysis, the high aseptic loosening rate reported in some series is probably related to a lack of rotational stability. Two patients with extensive distal femoral bone defects with preservation of the metaphyseal-diaphyseal junction underwent rTKA. Instead of performing a DFR with megaprostheses, partially impacted three-zone cones and standard cemented hinged implants were used with the aim of achieving better rotational stability. Both patients showed good evolution after a 12-month follow up. Clinical findings included a normal range of motion (0-100°) without any instability and preserved ability for full weight-bearing ambulation. No signs of prosthetic loosening appeared in the X-rays during follow up. To our knowledge, this was the first time a single partially anchored three-zone cone was used in massive metaphyseal femoral defects. It is an implant-dependent technique that additionally requires the preservation of the metaphyseal-diaphyseal junction, but may avoid the use of megaprostheses in some cases.

Bone loss in revision total knee arthroplasty (rTKA) makes achieving a well-fixed construct challenging. Metaphyseal sleeves and porous cones were designed to enhance fixation during rTKA and are typically used in combination with modular stems. However, there are limited outcome data comparing rTKA constructs with stems and sleeves or cones to those with stems alone. Therefore, we sought to compare re-revision rates in patients undergoing rTKA with cones/sleeves + stems to those with just stems.

We conducted a cohort study from a United States health care system's arthroplasty registry. The study sample included 2,882 aseptic rTKAs that included a stemmed component only (N = 2,264) or a stem and a cone/sleeve (N = 618) (2008 to 2022). Propensity score-weighted Cox proportional hazard regression was used to evaluate the risk of aseptic re-revision and re-revision due to loosening specifically.

At 8-year follow-up, after propensity score weighting, no difference was observed between stem + cone/sleeve compared with stem alone for aseptic re-revision (hazard ratio = 0.76, 95% confidence interval = 0.42 to 1.37) or aseptic loosening specifically (hazard ratio = 0.62, 95% confidence interval = 0.27 to 1.43).

In a cohort of over 2,500 rTKAs, we found the addition of metaphyseal sleeves or porous cones did not change the risk of aseptic re-revision overall or re-revision due to loosening specifically. Further large-scale studies with long-term follow-up are warranted to confirm these results.

Massive bone defects present significant challenges in complex primary total knee arthroplasty (TKA). Previous studies with limited sample sizes have demonstrated the potential of metaphyseal sleeves (MS) in addressing such defects. This study mainly aimed to assess the clinical outcomes and survivorship of MS utilized for reconstructing bone defects in complex primary TKA among East Asian patients, with a secondary focus on the use of scews for tibial residual bone defect.

A total of 3,672 primary TKAs were performed between January 2016 and December 2020, of which 106 procedures (87 patients) utilized MS in conjunction with straight stems to address bone defects. Among these, 55 (46 patients) incorporated screws for tibial residual bone defect, while 51 (41 patients) were performed without screws. The mean follow-up period was 57.86 months, during which demographic data, operative details, clinical and radiographic outcomes, complications, and implant survivorship were recorded and analyzed.

All cases demonstrated successful osteointegration, with both the endpoint reoperation and revision implant survival rates reaching 100%. The mean Hospital for Special Surgery (HSS) score significantly improved from 56.98 to 82.36 at the final follow-up, resulting in an overall excellent and good outcome rate of 95.40%. Knee conditions were notably worse in the screw group compared to the non-screw group; however, the clinical and radiographic outcomes between the two groups were comparable. Postoperative tibial end-of-stem pain was reported in 9.8% of the non-screw group, while none (0%) in the screw group, reflecting marginal significance (P = 0.0548).

The application of metaphyseal sleeves with straight stems represents a promising strategy for addressing massive bone defects in complex primary TKA among East Asian patients. The cement-screw technique, providing potential biomechanical advantages, emerges as a safe and effective solution for managing residual defects surrounding MS placement in tibial site.

In the landscape of knee-related health issues there has been a notable shift in treatment protocols. Nowadays, there is a growing trend toward primary total knee arthroplasty (TKA) in the event of periarticular knee fractures. A review of the literature on TKA in acute knee fractures has been done in order to provide scientific evidence to the four statements submitted for voting to the members of the European Knee Society (EKS).

A literature review has been performed around four topics of TKA in acute knee fractures, specifically: 1) The indications for TKA in acute knee fractures are undoubtful and clear; 2) Pre-existing osteoarthritis is not mandatory for the indication of TKA in acute fractures, while age, co-morbidities and type of fracture are; 3) A series of established criteria with scores to give indication for TKA (approved algorithm) is needed; and 4) This (complex) surgery must be performed in referral centers with all technical options and specific peri-operative management and post-operative care.

The panel of experts therefore believes that the indications cannot be considered undoubtful and clear. According to the literature up to the time of the consensus vote, there was no objective method for deciding on the treatment to offer the patient (Agree: 34.1%, Disagree: 61%, Abstain: 4.9%). It emerges that there are no mandatory conditions for the treatment of acute knee fractures with TKA (Agree: 32.3%, Disagree: 51.6%, Abstain: 16.1%). However, there are several characteristics to consider for a multifactorial evaluation rather than being limited to a single condition. While the consensus has highlighted a need for a scoring system to guide surgical decisions in periarticular knee fractures (Agree: 88.24%, Disagree: 8.82%, Abstain: 2.94%), research in the literature has confirmed that, to date, no validated algorithm exists. After the vote, a score was proposed, which requires validation. Although the panel of experts does not deem it necessary for this surgery to be reserved for reference centers (Agree: 32.35%, Disagree: 50%, Abstain: 17.65%), literature suggests that it is crucial that before undertaking knee arthroplasty in the setting of an acute fracture around the knee, the orthopedic surgeon is confident with all the necessary skills for a complex intervention that requires advanced knowledge and practical competence in osteosynthesis and revision TKA.

This discussion on the questions voted by the panel of experts has allowed for an in-depth exploration of a topic of interest, assessing indications, contraindications, types of possible treatment, and the critical aspects to consider when treating an acute fracture around the knee with a prosthesis. It is important to consider that the choice must be carefully weighed, evaluating the risks and benefits, with an increasingly need for a scoring system for selecting the most appropriate treatment.

As the number of revision total knee arthroplasties (rTKAs) continues to rise, there is increasing interest in the use of contemporary rotating hinge prostheses. These devices often incorporate porous cones to fill bone defects and enhance long-term fixation. This study evaluated the clinical and functional outcomes and survivorship in rTKA patients utilizing a rotating hinge prosthesis with flexible titanium (FT) cones, porous tantalum (PT) cones, or no cones.

From December 2014 to July 2023, 251 patients who underwent rTKA with a rotating hinge prosthesis were identified. Among them, 184 (73.3%) received cones: 93 tibial, 22 femoral, and 69 with combined cone fixation. Data were collected on demographics, surgical details, functional outcomes, complications, and implant survivorship. Statistical analyses were performed using a software program.

The average age of the cohort was 68 years (range, 34 to 98), the mean body mass index was 34.2 (range, 18.6 to 64), mean American Society of Anesthesiologists score was 2.97 (range, two to four), and the mean Charleson Comorbidity index 4.03 ± 1.88. The mean follow-up period was 1.85 years (range, zero to 7.9), with 97 (40%) men. Aseptic loosening of the hinge implant was observed in seven patients (2.8%) across the entire cohort. In patients who had cones, none were found to be loose despite loosening of the rTKA components. Postoperatively, wound complications were more common in the PT group (15.4%) compared to the FT (2.6%) and no-cone groups (14.9%, P = 0.017). There were no significant differences in reoperation rates across the groups.

The use of FT and PT cones with a novel rotating hinge prosthesis appears to be effective in achieving stable fixation and favorable early outcomes in rTKA. While aseptic loosening rates were low across all groups, the no-cone cohort had the highest proportion of cases. Long-term follow-up is necessary to validate these early findings and assess the durability and cost effectiveness of these implants over time.

Revision Total Knee Arthroplasty (RTKA) is complex, and induced bone loss might endanger implant fixation and joint stability. Intramedullary stems improve fixation throughout stress redistribution. The current study aims to compare the performance of short tibial stems with long tibial stems, investigating their intermediate-term radiographic and survival outcomes in RTKA. The main hypothesis is that the two types of tibial stems would exhibit similar complication and revision rates in mid-term follow-up.

Patients who underwent RTKA for all causes in a specialized arthroplasty center from 2010 to 2022 with minimum 2-year follow-up were included in this study. Patients receiving mega prosthesis or implants associated with sleeves or cones were excluded. The final groups consisted of 234 knees: 110 patients with short stems (SS) and 124 with long stems (LS). The mean age at surgery was 65.96 ± 8.73 years in SS and 67.07 ± 8.64 years in LS. The mean Body Mass Index (BMI) was 28.95 is SS and 30.88 in LS (p < 0.05). The average follow-up for SS group was 4.24 years and for LS 5.16 years (p < 0.05).

Complications and re-revisions did not differ significantly between two groups (p > 0.05). Pathological radiolucency was present in 20.91% in SS group and 33.87% in LS group (p < 0.02). Time-to-re-revision was shorter in SS group and occurred at a mean of 3.1 years, while LS failed at a mean of 5.1 years (p < 0.001).

The SS and LS may be comparable in terms of complications and re-revision. SS significantly fails almost 2 years earlier than long stem (p < 0.001). Additionally, there is a higher tendency for re-revision due to loosening in patients who present pathological radiolucency in SS group. To obtain the benefits of short stem and improve the longevity of the construct; adjuvant zone II (metaphyseal) fixation might be the clue.

To analyze the early- to mid-term clinical efficacy of personalized 3D-printed structural metal spacer technology in reconstructing massive bone defects during complex total knee arthroplasty (TKA) and revision surgery.

A single-center retrospective study was conducted on nine patients with severe bone defects who underwent TKA between 2018 and 2024. The general condition, surgical details, and clinical improvement of these patients were recorded and analyzed by clinical doctors.

The average surgical duration was 183.9 minutes (range, 125-240 minutes), with intraoperative blood loss of 133.3 mL (range, 100-200 mL). The average hospital stay was 18.2 days (range, 10-42 days), and the follow-up duration was 13.2 months (range, 2-57 months). The preoperative average American Knee Society Score of 51.2 points (range, 15-74 points) improved significantly to 95.0 points (range, 81-106 points) at the last follow-up. No cases of vascular or nerve injury, infection, fracture, or prosthetic loosening were observed.

The precise manufacturing of customized spacers that seamlessly integrate with the patient's skeletal structure ensures stability, adaptability, and improved surgical outcomes.

Introduction Total knee arthroplasty (TKA) is a well-established treatment for end-stage knee arthritis, providing substantial pain relief and functional improvement. However, the increasing need for revision TKA (RTKA) due to factors such as polyethylene wear, aseptic loosening, periprosthetic infection, and instability presents significant challenges. This study aimed to assess the mid- to long-term clinical and radiographic outcomes, implant survival rates, and complications associated with RTKA using a varus-valgus constrained (VVC) prosthesis. Methods This retrospective observational study analyzed patients who underwent RTKA with either VVC or condylar constrained knee prostheses at Sunshine Hospitals in Hyderabad, India, between January 1, 2010 and January 1, 2020, with a minimum follow-up of four years. Data were obtained from the joint registry. The inclusion criteria encompassed patients who underwent single-stage or two-stage RTKA for any indication, including periprosthetic joint infection (PJI), instability, or aseptic loosening. Functional outcomes were assessed using the Knee Society Score (KSS) and Oxford Knee Score (OKS), while radiolucent lines were evaluated with the updated Knee Society Roentgenographic Score. Implant survival rates were analyzed using Kaplan-Meier survival analysis. Results A total of 139 patients met the eligibility criteria for the final analysis, with a mean follow-up of 6.3 ± 2.4 years. The cohort had a mean age of 64.8 ± 7.8 years, comprising 90 females (64.7%), and a mean BMI of 29.3 ± 5.4. The primary indications for RTKA were PJI (70 cases, 50.4%) and aseptic loosening (47 cases, 33.8%). Significant postoperative improvements were observed in range of motion (from 73.2 degrees preoperatively to 104.3 degrees postoperatively), OKS (from 14.3 to 29.2), and KSS (from 48.2 to 74.9), all of which were highly significant (p < 0.001). Radiolucent lines were detected in 13 femoral components (9.35%) and 18 tibial components (12.95%), with one case progressing to aseptic loosening. Complications included superficial surgical site infections (two cases, 1.4%) and persistent prosthetic joint infections (three cases, 2.2%). Kaplan-Meier survival analysis demonstrated a 98.3% survival rate at 60 months, with reoperation for any cause as the endpoint. Conclusions The use of VVC prostheses in RTKA yields favorable long-term outcomes, demonstrating high survival rates and significant functional improvements. While managing bone defects and preventing postoperative infections remain challenges, meticulous surgical techniques and comprehensive postoperative care play a crucial role in achieving reliable results. These factors contribute to improved patient outcomes and enhanced prosthesis longevity in complex RTKA cases.

This systematic review and meta-analysis aimed to compare the clinical and radiological outcomes of patients undergoing revision total knee arthroplasty (rTKA) using uncemented press-fit stems (hybrid fixation) versus cemented stems (cemented fixation). It is also examined whether cemented fixation offers any superiority over hybrid fixation regarding implant survival, clinical function, imaging analysis and complication rates.

Following the PRISMA guidelines, a systematic review and meta-analysis were conducted on five databases (Pubmed, Scopus, Embase, Medline and Cochrane). Articles were evaluated according to levels of evidence (LoE). Retrospective studies were analysed with risk of bias in nonrandomised studies of interventions (Robins-I) and randomised controlled trials with risk of bias 2 (RoB-2). This review was registered in the International Prospective Register of Systematic Reviews database. Meta-analysis was performed using R software, with p < 0.05 considered statistically significant.

Data from 12 comparative studies with 1303 patients (1352 rTKAs) were analysed. Survival rates of hybrid and cemented fixations were comparable, with a significant trend favouring hybrid fixation (p = 0.04). Infection and aseptic loosening were the most common causes of failure. Radiographic failure rates showed no significant differences between fixation methods (p = 0.4). Meta-analysis indicated better results with hybrid fixation, although not statistically significant (KSS functional p = 0.15; KSS clinical p = 0.5). High heterogeneity was observed due to variations in patient characteristics and surgical strategies.

Both hybrid and cemented fixation techniques achieve satisfactory clinical results in rTKA, with hybrid fixation demonstrating an overall lower failure rate. The choice of fixation method must be tailored to individual patient characteristics and surgical considerations. Further high-quality randomised trials are needed to refine these results and optimise fixation strategies to improve patient outcomes.

Level IV.

Tibial fixation in revision total knee arthroplasty (rTKA) can present surgical challenges. It has been suggested that appropriate fixation in at least two of the three anatomical zones (epiphysis, metaphysis, and diaphysis) is essential for implant survival. However, supporting clinical data are lacking. In this retrospective case-control study, we investigated the relationship between zonal fixation of hybrid rTKA tibial components and re-revision total knee arthroplasty for aseptic loosening (rrTKA-AL).

All consecutive rTKAs with hybrid tibial components (May 2006 to December 2020) were screened for subsequent rrTKA-AL. A control group was randomly selected from the remaining cohort. Postoperative radiographs of rTKAs were scored in random order by three blinded observers for zonal fixation in the epiphysis (bone resection level below, at, or above fibular head; 0 to 2), metaphysis (number of sufficiently cemented zones; 0 to 4), and diaphysis (canal filling ratio (CFR); %). The intraclass correlation coefficient (ICC) was calculated to quantify the agreement between observers. Multivariate logistic regression analysis was performed to assess the relationship between zonal fixation and rrTKA-AL.

Overall, 33 patients underwent a further rrTKA-AL from a total of 1,173 rTKAs where hybrid tibial components (2.8%) were used. Patients requiring rrTKA-AL had a significantly lower epiphyseal bone resection level (OR 0.43; 95% CI 0.23 to 0.76; p = 0.006), lower number of adequately cemented zones (OR 0.50; 95% CI 0.30 to 0.79; p = 0.004), but no difference in CFR (p = 0.858). Furthermore, patients needing rrTKA-AL had more frequently previous revisions (p = 0.047), a higher rate of a prior use of a stemmed tibial component (p = 0.011), and a higher Anderson Orthopaedic Research Institute classification (p < 0.001). Agreement of zonal fixation between observers was good (ICC 0.79 to 0.87).

Patients in need of subsequent rrTKA-AL had lower epiphyseal bone resection levels and a lower number of sufficiently metaphyseal cemented zones following rTKA. These results emphasize the importance of appropriate metaphyseal fixation at rTKA. With this information, orthopaedic surgeons can identify patients at greater risk for rrTKA-AL and optimize their surgical technique in revision knee arthroplasty surgery.

The total number of total knee arthroplasty performed is rising, and the number of revisions is rising accordingly. Periprosthetic joint infection emerged in recent years as a leading cause of total knee revisions. Bone loss is a real challenge when facing septic knee revisions since radical debridement is crucial to overcome infection. Many devices have already demonstrated to reliably address bone loss and guarantee enhanced fixation. However, the role of balancing metaphyseal fixation and its interplay with the level of constraint has not been elucidated yet.

An institutional arthroplasty registry was retrospectively reviewed looking for patients who underwent two-stage revision of the knee and metaphyseal cones implantation. Patients were divided into two groups based on the presence of cones only on one side (femoral or tibial, Group U) or both femoral and tibial side (Group B). Failure, aseptic loosening, and revision rates were compared between groups, as were values of patient-reported outcome measure. Kaplan-Meier analysis was used to assess survival of implants.

A total of 65 patients were included in the analysis and were evaluated at a mean final follow-up of 4 years (range, 2-7). Mean age was 67 (range, 43-81) years. Mean BMI was 27.4 (range, 20-37) kg/m2. The overall mean KSS, OKS, ROM significantly increased from baseline values to last follow-up (p < 0.001). Kaplan-Meier analysis demonstrated that patients included in Group U had a significantly lower rate of implant survival compared to those included in Group B.

Patients undergoing revision total knee arthroplasty for periprosthetic infection present considerable rates of complication and failure. Management of bone loss represents a concern for the surgeon, who must achieve a stable fixation. Our study demonstrated that implants characterized by an unbalanced metaphyseal fixation are at higher risk of aseptic loosening and consequent revision, especially when coupled with hinged inserts.

Accelerometer-based navigation (OrthAlign) is the first computer-assisted surgical navigation system approved for use in the setting of revision total knee arthroplasty (TKA) in the United States. The senior author has used this technology in the revision setting for several years and developed the individualized, reproducible technique. The 4 goals during revision TKA are to (1) gain adequate exposure for the safe explanation of prior implants, (2) address any resultant bone loss, (3) restore the joint line via distal femur metal augmentation, and (4) ensure adequate stability through gap-balancing techniques and increasing the constraint of the revision implants as needed. This technique guide illustrates how accelerometer-based navigation (OrthAlign) can achieve these goals in the revision TKA setting.

The primary objective of revision total knee surgery is to achieve solid bone fixation. Generally, this could be accomplished using sleeves and long stems, which require substantial remaining bone stock and may increase the risk of stem tip pain. An alternative approach involves the use of customized diaphyseal cones, which can preserve the integrity of the bone canal. This study evaluates the impact of employing femoral diaphyseal cones with various stem lengths on stress distribution and relative motion.

CT scan data from five patients were used to generate the 3D model of the femur, cement, customized stems, and cones, along with assigning patient-specific material for each candidate's femur. Three different stem lengths, both with and without the customized cone, were assessed under three gait loading conditions to compare the resulting Von Mises stress distribution and relative motion.

Analysis indicated that the use of customized femoral cones moderately increases stress distribution values up to 30 % while significantly reducing relative motion at the femoral canal-cone interface by nearly 60 %. The presence of the cone did not significantly alter relative motion with varying stem lengths, although stem length variation without a cone substantially affected these values.

Incorporating cones alongside stems enhances metaphyseal fixation, reduces stress shielding, potentially allowing for the use of shorter stems. Furthermore, cones promote osseointegration by minimizing relative motion, ultimately improving prosthetic stability.

The purpose of this retrospective study was to compare the medium-term clinical and radiographic outcomes of two series of patients treated for revision TKA: one implanted with trabecular metal (TM) augments and one implanted with classic titanium augments.

A total of 85 patients with a type 2 AORI defect underwent revision TKA and were treated either with TM epiphyseal augments directly screwed in the bone or with traditional titanium augments. There were 46 patients in the TM group and 39 patients in the titanium group included in the study. All the patients received the same varus-valgus constrained implant and no metaphyseal fixation devices were used.

After a mean follow-up of 66.4 months, no statistically significant difference was observed in terms of failure for aseptic loosening between the two groups (4% in the TM group and 7.8% in the titanium group, p = 0.35). The ten-year survival using aseptic loosening as endpoint was 90.5% (95% CI 94.1-98.6) in the TM group and 85% (95% CI 101.9-119.3) in the titanium group (p = 0.26). A statistically significant difference was detected for the presence of RLL. No RLL were found under the studied TM augments compared to 13.7% of the titanium augments (p = 0.01).

The use of TM augments directly screwed to the epiphysis of the femur and the tibia reduced the incidence of RLL compared to standard titanium augments during revision TKA with promising medium-term results.

Porous metaphyseal cones are frequently utilized during revision total knee arthroplasty (TKA) procedures. The purpose of the present study was to evaluate 3D-printed metaphyseal cones used for revision TKA, with specific emphasis on implant survivorship, radiographic appearance, and clinical outcomes after short-term follow-up.

We identified 740 cones (498 tibial, 242 femoral) that had been inserted during 533 revision TKA procedures that had been performed at a single tertiary care academic institution. Aseptic loosening (n = 199), periprosthetic joint infection (PJI) (n = 183), and instability (n = 84) were the most common reasons for the index revision. Type-2B or 3 bone loss was present in 67% of the knees. The mean age was 66 years, the mean body mass index was 34 kg/m 2 , and 55% of the patients were female. Serial radiographs were reviewed. The mean duration of follow-up was 4 years.

The 5-year cumulative incidence of cone revision for aseptic loosening was 1% (95% confidence interval [CI], 0% to 3%). The 5-year cumulative incidence of any cone revision or removal was 6% (95% CI, 4% to 9%). In total, 37 cones (19 femoral, 18 tibial) were revised, with PJI (n = 23; 14 recurrent), periprosthetic femoral fracture (n = 3), arthrofibrosis (n = 3), and aseptic loosening of the femoral component and femoral cone (n = 3) as the most common reasons for cone revision. The 5-year cumulative incidence of any TKA re-revision was 14% (95% CI, 11% to 18%). There were a total of 67 re-revisions, with PJI (n = 38), persistent drainage (n = 6), and extensor mechanism disruption (n = 3) being the most common reasons. Radiographically, 2 unrevised femoral cones and 1 unrevised tibial cone appeared to be possibly loose; all 3 cones were in knees with distal femoral replacements or hinged constructs.

This large series showed that 3D-printed titanium metaphyseal cones were very durable at short-term follow-up, with a 5-year cumulative incidence of cone revision for aseptic loosening of 1%. PJI was the most common reason for cone revision and any revision.

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Highly porous metal tibial metaphyseal cones (TMCs) are commonly utilized in revision total knee arthroplasty (TKA) to address bone loss and obtain biologic fixation. Mid-term (5 to 10 year) studies have previously demonstrated excellent survivorship and high rates of osseointegration, but longer-term studies are lacking. We aimed to assess long-term (≥ 10 year) implant survivorship, complications, and clinical and radiographic outcomes after revision TKA with TMCs.

Between 2004 and 2011, 228 revision TKAs utilizing porous tantalum TMCs with stemmed tibial components were performed at a single institution and were retrospectively reviewed. The mean age at revision was 65 years, the mean body mass index was 33, and 52% were women. Implant survivorship, complications, and clinical and radiographic outcomes were assessed. The mean follow-up was 6.3 years.

The 10-year survivorship free of aseptic loosening leading to TMC removal was 97%, free of any TMC removal was 88%, free of any re-revision was 66%, and free of any reoperation was 58%. The most common indications for re-revision were periprosthetic joint infection, instability, and aseptic femoral component loosening. The 10-year nonoperative complication rate was 24%. The mean Knee Society scores increased from 38 preoperatively to 69 at 10 years. There were 8 knees that had evidence of partial, progressive tibial radiolucencies at 10 years.

Porous tantalum TMCs demonstrated persistently durable longer-term survivorship with a low rate of implant removal. The rare implant removals for component loosening or instability were offset by those required for periprosthetic joint infection, which accounted for 80% of cone removals. Porous tantalum TMCs provide an extremely reliable tool to address tibial bone loss and achieve durable long-term fixation in revision TKA.

IV.

Although hinged prostheses have been used successfully in complex revision total knee arthroplasty (TKA), concerns exist regarding early failure due to aseptic loosening and other mechanical complications. The use of metaphyseal cones and hybrid cement fixation have been studied in unlinked constrained primary or revision TKA, but their impact on the survivorship of hinged prostheses has yet to be investigated.

We identified a consecutive series of 164 hinged prostheses and collected data on demographics, indications, complications, and re-revisions in patients who had fully cemented versus hybrid stems, with and without metaphyseal cones. A multivariate analysis was performed to identify independent variables associated with re-revision as the primary end point.

In total, 84 patients (51.2%) had fully cemented stems, and 80 patients (48.8%) had hybrid stems. Cones were used in 73 patients (44.5%). At a mean follow-up of 3.4 ± 2.2 years, 42 patients underwent re-revision (25.8%), most commonly for infection (12.2%), followed by loosening (6.7%) and periprosthetic fracture (3.7%). Patients who had fully cemented stems had lower re-revision rates than hybrid fixation constructs (19 versus 26%, P = .043). Using multivariable regression, a construct with hybrid fixation with cones (odds ratio = 2.39; P = .037) was an independent risk factor for failure. Utilization of cones alone did not have an effect on re-revision rates at 3.4-year follow-up.

While we found no difference with the use of cones, patients undergoing revision TKA with a hinge prosthesis and fully cemented stems had better overall survivorship than hybrid stems.

Tibial bone defects are commonly encountered in revision total knee arthroplasty (rTKA) and can be managed with metaphyseal cones or sleeves. Few studies have directly compared tibial cones and sleeves in rTKA, and none have limited this comparison to the most severe tibial defects. The purpose of this study was to evaluate and compare the outcomes of metaphyseal cones and sleeves for tibial reconstruction in rTKA regarding implant fixation and clinical outcomes.

A retrospective review was conducted on patients undergoing rTKA in which metaphyseal cones or sleeves were utilized for addressing metaphyseal bone loss (34 cones and 18 sleeves). Tibial bone loss was classified according to the Anderson Orthopaedic Research Institute bone defect classification, with types 2B and 3 being included. Patient-reported outcomes and postoperative complications were collected, and a radiographic evaluation of osseointegration or loosening was performed.

There were 52 knees included (34 cones, 18 sleeves), with a median follow-up of 41.0 months. All-cause implant survival was 100% at 2 years and 96% (95% confidence interval: 76 to 99%) at 4 years, with 98% of tibial components demonstrating osseointegration at the final follow-up. During follow-up, there were a total 11 revisions, of which 1 sleeve was revised secondary to implant loosening. Tibial sleeves had a higher risk of revision compared to tibial cones (P < .01), and sleeves fixed with a hybrid technique were more likely to need revision than cones fixed by the same method (P = .01).

Porous metaphyseal tibial cones and tibial metaphyseal sleeves both performed well at a 41-month median follow-up with no difference in aseptic survivorship between the 2 constructs. Both demonstrate high rates of osseointegration, low rates of aseptic failure, and significant improvement in Knee Society Scores in patients with severe tibial defects in rTKA.

In revision total knee arthroplasty, addressing significant bone loss often involves the use of cemented or press-fit stems to ensure implant stability and long-term fixation. A possible alternative to stem was recently introduced utilizing custom-made porous metaphyseal cones, designed to reconstruct the missing tibial and femoral geometries. Early clinical and radiological assessments have shown promising results. The objective of this research was to biomechanically evaluate the performances of these custom-made cones.

The biomechanical study was conducted using a validated finite element model. The bone geometries of a patient (selected for their history of four knee revisions due to infection and periprosthetic fractures, followed by a successful treatment with custom-made 3D-printed metaphyseal cones) were employed for the study. On these bone models, different revision scenarios were simulated and examined biomechanically: (A) custom-made cementless metaphyseal cones; (B) cemented stems; (C) press-fit stems; (D) distal femoral reconstruction with press-fit stem. All the models were analyzed at 0 °and 90 °of flexion, under physiological load conditions simulating daily activities; stress distribution, average Von-Mises stresses and risk of fracture were then analyzed and compared among configurations.

The use of custom-made 3D-printed cones exhibited the most favorable stress distribution in both femoral and tibial bones. Tibial bone stress was evenly distributed in custom-made cone configurations, while stress concentration was observed in distal regions for the other scenarios. Additionally, custom-made cones displayed overall homogeneity and lower stress levels, potentially contributing to limit pain. Symmetrical stress distribution was observed between the lateral and medial proximal tibia in custom-made cone models, whereas other scenarios exhibited uneven stress, particularly in the anterior tibial bone.

The biomechanical analysis of porous custom-made metaphyseal cones in re-revision arthroplasties is in agreement with the positive clinical and radiological outcomes. These findings provide valuable insights into the potential benefits of using custom-made cones, which offer more uniform stress distribution and may contribute to improve patient outcomes in revision TKA procedures. Further studies in this direction are warranted to validate these biomechanical findings.

Metaphyseal cones with cemented stems can be successfully utilized in most revision total knee arthroplasties (TKAs). However, if the diaphysis has been previously violated, fixation of the cemented stem, which is important for cone ingrowth and construct survival, can be compromised. The initial results of our novel technique combining diaphyseal impaction bone-grafting with a metaphyseal cone were promising but required additional study. The purpose of the present study was to assess results of this technique in a larger cohort.

A metaphyseal cone combined with diaphyseal impaction grafting and a cemented stem was utilized in 88 revision TKAs at our institution, including 35 from our prior study. The mean age at the time of revision was 67 years, and 67% of patients were male. Patients had had a mean of 4 prior knee arthroplasty procedures. The 2 most common reasons for revision were aseptic loosening (78%) and 2-stage reimplantation for periprosthetic joint infection (PJI) (19%). The mean follow-up was 4 years.

At the time of the latest follow-up, no cone-impaction grafting constructs required re-revision for aseptic loosening. Five-year survivorship free from any revision of the cone-impaction grafting construct and free from any reoperation was 95% and 65%, respectively. A total of 25 knees (28%) underwent reoperation, with the 2 most common indications being PJI and periprosthetic fracture. All cones were osseointegrated, and all bone graft appeared stable or incorporated. One patient had radiographic evidence of tibial component loosening despite a well-fixed cone; however, this patient was asymptomatic and had not undergone revision at 9 years.

When presented with a sclerotic, polished diaphyseal canal with deficient cancellous bone and concomitant metaphyseal bone loss, our technique of combining diaphyseal impaction grafting with a metaphyseal cone proved extremely durable in this larger series of patients. No cone-impaction grafting constructs required re-revision for aseptic loosening.

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

The second-generation metaphyseal cone was useful in managing bone defects in revision knee arthroplasty. However, due to the anatomical constraints in Asian osteometry, the authors utilized a novel free-hand burring technique instead of cannulated reaming for bone preparation. We reported the short-term outcomes of our surgical techniques specific to Asian osteometry.

We conducted a case series by consecutively recruiting 13 female and 12 male patients (involving 25 knees), with a mean age of 71 years (range, 54-88 years). The patients underwent revision total knee arthroplasty during the period from April 2017 to June 2022. Twenty-three tibial cones and 4 femoral cones using free-hand burring technique were implanted. The mean follow-up duration was 51 months (range 18-80 months). Due to the relatively small bone size and meta-diaphyseal center mismatch in the Asian knees, the free-hand burring technique instead of the cannulated reaming technique was adopted in preparing for cone implantation. The clinical outcomes were knee ranges of motion, the Knee Society Knee scores (KSS), end-of-stem pain, infection, and the need for revision surgery. The radiological outcomes included osteointegration, fracture, and loosening.

Mean knee range of motion improved from 83 degrees (range 0°-120°) preoperatively to 106 degrees (range 60°-125°) postoperatively (P < 0.001). Mean KSS improved significantly from 29 (range 0-70) to 69 (range 5-100) (P < 0.001). All cones were osteointegrated. One case had transient end-of-stem pain, two developed intraoperative minor femoral fractures and one suffered from recurrent infection that did not require cone revision. Cone revision-free survivorship was 100%. There was no aseptic loosening.

The second-generation cone implanted with free-hand burring bone preparation yielded promising short-term outcomes in Asian knees.

We compared revision rates and reasons for revision for primary total knee arthroplasty (TKA) performed for osteoarthritis with and without tibial stem extensions.

Data from the Australian Orthopaedic Association National Joint Replacement Registry were used to compare all-cause revision, reason, and type of revision between primary TKA using stemmed tibial prostheses and non-stemmed prostheses.

All-cause revision for TKA with stem extension was higher for the first 6 months (hazard ratio [HR] 1.47; 95% confidence interval [CI]1.19 to 1.82; P < .001); while after 1.5 years TKA with stem extension had a lower rate of revision (HR 0.84; 95% CI 0.73 to 0.97; P = .01). Stemmed components were more likely to be revised for infection between 3 months and 1.5 years after surgery (HR 1.39; 95% CI 1.05 to 1.83; P = .02). The revision rate for aseptic loosening was lower in the stemmed group beyond 2 years (HR = 0.45; 95% CI 0.31 to 0.63; P < .001). Insert-only revision was higher in the stemmed group at all times (HR = 1.42; 95% CI 1.21 to 1.66, P < .001). Isolated tibial component revision was lower in the stemmed group at all times (HR 0.47; 95% CI 0.29 to 0.74; P = .001). Aseptic loosening for tibial component-only revision was significantly lower in the stemmed group at all times (HR 0.23; 95% CI 0.11 to 0.50; P < .001).

Patients undergoing primary stemmed TKA have lower rates of all-cause revision beyond 1.5 years and tibial component-only revision at all times. Further investigation is required to preoperatively select patients that benefit from augmentation with stems.

Both porous metal cones and metaphyseal sleeves are excellent implants for reconstructing severe bone defects in the knee joint, but they both exhibit design limitations. The porous metal cone, especially, has significant room for improvement in its shape design. The existing porous metal cones often feature a conical external surface with a relatively small taper, potentially compromising both rotational and axial stability. To improve both axial and rotational stability in porous metal cones, we developed a 3D-printed stepped porous metal cone. This study aimed to assess the short-term clinical outcome of the 3D-printed stepped porous metal cone and to compare it with the clinical outcome of patients who underwent revision total knee arthroplasty (rTKA) with the metaphyseal sleeves during the same period.

Patients who underwent total knee arthroplasty revision with metaphyseal bone defect reconstruction from 2019 to 2021 were retrospectively analyzed. A total of 61 patients were enrolled in the study, including 15 patients using 3D-printed stepped porous metal cones and 46 patients using metaphyseal metal sleeves. Thirty patients using metaphyseal sleeves were screened by propensity score matching method and compared with those using stepped cones. Analysis included the American Knee Society Score, the Hospital for Special Surgery knee score, the Western Ontario and McMaster Universities Arthritis index, the Short Form 12 (SF-12) health survey, and radiographic assessment with a mean follow-up of 28.5 ± 8.3 months. To conduct comparative analyses, unpaired Student's t-tests were employed for continuous variables, while categorical variables were analyzed using the appropriate Fisher exact or chi-squared test.

In this study, the survival rates of both the stepped cone and metaphyseal sleeve were 100%. There was no statistically significant difference in postoperative knee function scores between the two groups (p > 0.05). However, patients in the cone group had significantly higher mental component summary scores on the SF-12 scale (p < 0.05) and higher increases in mean postoperative physical component summary scores than patients in the sleeve group (p < 0.05). In addition, patients in the cone group experienced fewer intraoperative and postoperative complications compared to the sleeve group.

The 3D-printed stepped porous metal cone can effectively reconstruct bone defects in complex rTKA and provide satisfactory early clinical and radiographic results. The 3D-printed stepped cone provides a more stable structure similar to the sleeve while maintaining the original benefits of the cone making it a promising choice for rTKA.

Pain at the tip of the stem of a knee prosthesis (End-of-Stem Pain) is a common problem in revision total knee arthroplasty (TKA). It may be caused by a problematic interaction between stem and bone, but the exact biomechanical correlate is still unknown. On top of this, there is no biomechanical study investigating End-of-Stem Pain at the distal femur using human specimens. Aim of this study was to find out whether the implantation of a revision total knee implant leads to high femoral surface strains at the tip of the stem, which the authors expect to be the biomechanical correlate of End-of-Stem Pain. We implanted 16 rotating hinge knee implants into 16 fresh-frozen human femora using the hybrid fixation technique and comparing two reaming protocols. Afterwards, surface strains on these femora were measured under dynamic load in two different load scenarios (climbing stairs and chair rising) using digital image correlation (DIC) and fracture patterns after overcritical load were analysed. Peak surface strains were found at the tip of the stem in several measurements in both load scenarios. There were no significant differences between the two compared groups (different trial sizes) regarding surface strains and fracture patterns. We conclude that implantation of a long intramedullary stem in revision TKA can lead to high surface strains at the tip of the stem that may be the correlate of femoral End-of-Stem Pain. This finding might allow for a targeted development of future stem designs that can lead to lower surface strains and therefore might reduce End-of-Stem Pain. Digital Image Correlation proved valid for the measurement of surface strains and can be used in the future to test new stem designs in vitro.

Recent advances in total knee arthroplasty (TKA) have been driven by a growing focus on evidence-based medicine. This transition is reflected in the critical appraisal of both, the quality of work and the potential impact on the orthopedic community. The purpose of our study was to (1) identify the top 100 most-cited articles in TKA in the last decade and from all-time, and (2) compare methodological rigor of the most-cited articles in TKA in the last decade to articles all-time by level of evidence.

The top 100 cited articles were recorded for manuscripts from the last decade, January 1, 2012 to December 31, 2022, and manuscripts from all-time for TKA. We collected authors, year of publication, journal of the article, country of origin of authors, article type (basic science article, clinical research article), level of evidence, methodological index for non-randomized studies score, physiotherapy evidence database scale, and citation density (total citations/years published).

The largest number of studies for all-time TKA (53.0%) and decade TKA (42.0%) were Level III. The average methodological index for non-randomized studies score for comparative studies was 18.7 for all-time TKA and 20.7 for decade TKA (P < .001). The average physiotherapy evidence database score was 6.1 for all-time TKA and 8.1 for decade TKA (P > .05). The highest citation density for all-time TKA was 111 and for past decade was 63. The number of level II studies in TKA increased from 19.0% from all time to 38.0% from the last decade (P < .05).

Our findings of improved methodologies over time reflect positive steps toward evidence-based practice in TKA. A continued focus on producing methodologically sound studies may guide evidence-based clinical decision-making.

The purpose of this study is to analyze the indications, complications, survivorship and clinical/functional outcome of metaphyseal sleeves as a treatment option in revision total knee arthroplasty.

A systematic review was made following the PRISMA recommendations on the use of metaphyseal sleeves for revision total knee arthroplasty. We included prospective and retrospective studies published in the last 10 years looking at implant survivorship, clinical and functional outcome with a minimum follow-up of 2 years.

The included studies showed good both functional and clinical outcomes. The overall reoperation rate was 16.2%, with an overall survival rate of 92.2% and aseptic survivorship of 98.2%.

Metaphyseal sleeves are a good treatment option for this surgery, especially in AORI II or III type bone defects, achieving good intraoperative and primary stability of the implant, with good and rapid osseointegration.

The evaluation, classification, and treatment of significant bone loss after total knee arthroplasty (TKA) continue to be a complex and debated topic in revision TKA (rTKA). Despite the introduction of new evidence and innovative technologies aimed at addressing the approach and care of severe bone loss in rTKA, there is no single document that systematically incorporates these newer surgical approaches. Therefore, a comprehensive review of the treatment of severe bone loss in rTKA is necessary. The Stavros Niarchos Foundation Complex Joint Reconstruction Center Hospital for Special Surgery, dedicated to clinical care and research primarily in revision hip and knee replacement, convened a Management of Bone Loss in Revision TKA symposium on June 24, 2022. At this meeting, the 42 international invited experts were divided into groups; each group was assigned to discuss questions related to 1 of the 4 topics: (1) assessing preoperative workup and imaging, anticipated bone loss, classification system, and implant surveillance; (2) achieving durable fixation in the setting of significant bone loss in revision TKA; (3) managing patellar bone loss and the extensor mechanism in cases of severe bone loss; and (4) considering the use of complex modular replacement systems: hinges, distal femoral, and proximal tibial replacements. Each group came to consensus, when possible, based on an extensive literature review and interactive discussion on their group topic. This document reviews each these 4 areas, the consensus of each group, and directions for future research.

The purpose of this study is to analyse the indications, complications, survivorship and clinical/functional outcome of metaphyseal sleeves as a treatment option in revision total knee arthroplasty.

A systematic review was made following the PRISMA recommendations on the use of metaphyseal sleeves for revision total knee arthroplasty. We included prospective and retrospective studies published in the last 10 years looking at implant survivorship, clinical and functional outcome with a minimum follow-up of 2 years.

The included studies showed good both functional and clinical outcomes. The overall reoperation rate was 16.2%, with an overall survival rate of 92.2% and aseptic survivorship of 98.2%.

Metaphyseal sleeves are a good treatment option for this surgery, especially in AORI II or III type bone defects, achieving good intraoperative and primary stability of the implant, with good and rapid osseointegration.

The use of a sliding prosthesis in total knee arthroplasty (TKA) with increased stress is an intermediate solution in primary surgery, between posteriorly stabilized prostheses and hinged prostheses, in cases of ligamentous laxity and/or loss of bone substance. Favorable results have been reported in the medium term but to our knowledge, this type of prosthesis has not been evaluated in Europe beyond 10 years of follow-up. We therefore conducted a retrospective study in order to carry out: 1) the study of the survival of the Legacy Constrained Condylar Knee (LCCK™) prosthesis in primary surgery, 2) the analysis of complications, functional scores and radiographic data, 3) the analysis of the link between the diaphyseal filling rate and prosthetic loosening.

The LCCK™ sliding prosthesis with increased constraint has equivalent long-term survival and clinical results to standard posteriorly stabilized TKA and superior to hinged TKA.

A retrospective series of 141 LCCK™ implanted in 134 patients between 1997 and 2010 was analyzed. Survival was assessed with censoring through an evaluation of partial or total revision of the implants. The functional results were evaluated using the IKS and Oxford 12 scores. Data regarding the Canal Fill Ratio (CFR) and the presence of pathological periprosthetic lines were also collected.

The average follow-up was 11.3±5.3years with a maximum follow-up of 22.7years. Survival at 20years was 90.8% [95% CI: 83.7-95.7]. The rate of early complications was 13.5% (19/141), predominantly comprised of venous thrombosis (6/141), hematomas (3/141 including two requiring surgical drainage), stiffness (3/141) and early infections (3/141). The rate of late complications was 17% (24/141), led by stiffness (4.4%; 6/141), infections (2.9%; 4/141) and hardware failure (2. 2%; 3/141). Ten of the 141 patients (7.1%) had LCCK failure, including 3 (2.1%) for stiffness, 3 (2.1%) for hardware failure, 2 (1.4%) for infection, 1 (0.7%) for laxity and 1 (0.7%) for a periprosthetic fracture. No aseptic loosening was found. The total IKS score went from 65 [0-116] to 143 [79-200] at follow-up, the IKS knee score went from 30 [0-66] to 85 [44-100], and the IKS function score went from 35 [0-70] to 57 [0-100]. The Oxford score went from 14 [2-25] to 34 [15-48] at follow-up. Only two patients (1.4%) presented with a partial periprosthetic line. The tibial CFR was 0.81 and the femoral CFR was 0.76. The influence of the CFR could not be analyzed due to the absence of loosening.

The LCCK™ prosthesis in primary surgery has good medium-term survival, a significant improvement in functional scores and a complication rate comparable to posteriorly stabilized prostheses. The complication rate is lower than that of hinged prostheses.

IV; single-center retrospective study.

Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis).

Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system.

At a mean follow-up of 90 months (64 to 130), only two out of 245 cases failed due to aseptic loosening. Intraoperative grading yielded mean scores of 1.87 (95% confidence interval (CI) 1.82 to 1.92) for the femur and 1.96 (95% CI 1.92 to 2.0) for the tibia. Only 3.7% of femoral and 1.7% of tibial reconstructions fell below the 1.5-point threshold, which included the two cases of aseptic loosening. Interobserver reliability for postoperative radiological grading was 0.97 for the femur and 0.85 for the tibia.

A minimum score of 1.5 points for each skeletal segment appears to be a reasonable cut-off to define sufficient fixation in rTKA. There were no revisions for aseptic loosening at mid-term follow-up when this fixation threshold was achieved or exceeded. When assessing first-time revisions, this novel grading system has shown excellent intra- and interobserver reliability.

The number of primary and revision Total Knee Arthroplasty (TKA) cases are expected to increase in future. There are various advantages and disadvantage to employing either of the two main types of stem fixation methods - cemented or hybrid technique. This review aimed to study the most optimal fixation method for revision TKAs by comparing radiological outcomes and re-revision rates.

A systematic review and meta-analysis was performed using PubMed and Cochrane Library from 2010 to identify studies explicitly comparing outcomes between cemented against hybrid fixation revision TKA techniques, with a minimum follow up of at least 24 months. A total of 8 studies was included in this review. Egger's test and visual inspection of the funnel plot did not reveal publication bias.

There was no statistically significant difference in radiological failure and loosening (OR 0.79, CI 0.37-1.66, I2 = 29%, p = 0.22), all causes of re-revision (OR 1.03, CI 0.73-1.44, I2 = 0%, p = 0.56) and aseptic revision (OR 0.74, CI 0.27-2.02, I2 = 0%, p = 0.41) between cemented and hybrid techniques. Functional and pain outcomes compared between the two fixation techniques were largely similar across the studies included in this meta-analysis.

Despite a trend favouring hybrid stems in revision TKA, current evidence revealed that radiological outcomes and re-revision rates are largely similar between cemented and hybrid fixation techniques.