Isolated posterior malleolar fracture is a rare condition, and this fracture is usually overlooked and diagnosed as an ankle sprain owing to a lack of awareness and difficulty in diagnosis. Posterior ankle impingement syndrome (PAIS) is relatively common in athletes and is usually caused by trauma or overuse. The impingement occurs due to repeated compression of a bony or soft tissue. Here, we report a rare case of a 17-year-old rugby player presenting with posterior ankle impingement caused by nonunion of an isolated posterior malleolar fracture. This patient was treated using a posterior ankle arthroscopic excision. At 16 weeks postoperatively, his ankle and hallux pain disappeared, and he returned to sports activities with no morbidities related to the surgical procedure. Based on a computed tomography scan, the bone fragment causing the impingement was resected, and the union of the residual posterior malleolar fragment was verified.

A symptomatic os trigonum is a common cause of posterior ankle pain that has been traditionally managed with open excision. Minimally invasive surgery (MIS) has been proposed as an alternative to open excision for improved outcomes and decreased complication rates; however, no systematic review to date has examined the utilization of MIS for a symptomatic os trigonum.

To examine patient outcomes, return to sport, and complications associated with MIS for a symptomatic os trigonum.

Systematic review; Level of evidence, 4.

A systematic review was performed on February 22, 2023, using the PubMed, CINAHL, MEDLINE, and Web of Science databases from database inception until February 22, 2023, on the topic of MIS for a symptomatic os trigonum.

Of 885 articles retrieved from an initial search, 17 articles (N = 435 patients) met full inclusion criteria. The mean age of the cohort was 26.01 ± 4.68 years, with a mean follow-up time of 34.63 ± 18.20 months. For patients treated with MIS, the mean preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score was 55.85 ± 12.75, the mean final postoperative AOFAS score was 94.88 ± 4.04, the mean preoperative visual analog scale pain score was 7.20 ± 0.43, and the mean final postoperative visual analog scale score was 0.71 ± 0.48. The mean time to return to sport for patients undergoing MIS was 7.76 ± 1.42 weeks. MIS had an overall complication rate of 5.0%, the majority of which consisted of transient neurapraxia of the sural or superficial peroneal nerve.

Minimally invasive management of a symptomatic os trigonum appears to be a viable alternative to open surgery in terms of outcomes, return to sport, and complication rates. More high-quality evidence will be required to definitely recommend minimally invasive approaches as the standard of care over open surgery.

Os trigonum syndrome represents a cause of posterior ankle pain that is predominantly seen in athletes. The os trigonum ossicle forms from a secondary ossification center of the talus and is located at its posterior aspect in an interval between the posterior lip of the tibial plafond and calcaneus. The os trigonum ossicle is often an incidental finding and asymptomatic. However, repetitive plantarflexion and push-off maneuvers can cause symptoms and lead a patient to pursue orthopedic care.

A review of the literature was conducted using the PubMed search engine with the following keywords: "os trigonum", "os trigonum ossicle", "os trigonum syndrome", "posterior ankle impingement", and "Stieda process".

The pertinent anatomy, clinical presentation, diagnostic evaluation, and treatment of os trigonum syndrome were reviewed in the literature and are extensively discussed in this article.

Os trigonum syndrome represents a potential cause of posterior ankle pain that needs thorough evaluation regarding history, physical examination, and imaging. Once diagnosed, treatment ranges from conservative to surgical interventions depending on surgeon preference and specific case presentation. [Orthopedics. 2024;47(2):e67-e72.].

This article is devoted to managing posterior ankle impingement syndrome and its management using endoscopic to arthroscopic surgical instrumentation. The authors explore the critical anatomy, pathogenesis, and clinical examination. Operative techniques, including the approach, and instrumentation used, are outlined. The postoperative protocol is discussed. Finally, a literature review is provided, which also defines known complications.

Posterior ankle impingement is typically seen in athletes, primarily dancers and soccer players, secondary to dynamic and repetitive push-off maneuvers and forced hyperplantarflexion. Posterior ankle impingement results from chronic, repetitive trauma to the posterior ankle capsule, flexor hallucis longus tendon, and/or os trigonum. It is important to perform a thorough workup by isolating and testing the posterior compartment muscles and obtaining proper imaging with radiographs to identify any osseous abnormalities and MRI to evaluate the soft tissue structures. Nonsurgical treatment includes activity modification, physical therapy, and steroid injections.

Surgical treatment of symptomatic posterior ankle impingement consists of resection of the bony impediment and/or debridement of soft tissue. Historically, open techniques were used to perform surgery with good results. However, since the introduction of endoscopic techniques, advantages attributed to these techniques are shorter recovery time, fewer complications, and less pain.

The primary purpose was to determine whether endoscopic surgery for posterior ankle impingement was superior to open surgery in terms of functional outcome (American Orthopaedic Foot & Ankle Society [AOFAS] score). The secondary aim was to determine differences in return to full activity, patient satisfaction, and complications.

Systematic review and meta-analysis.

MEDLINE, EMBASE (Classic), and CINAHL databases were searched. Publication characteristics, patient characteristics, surgical techniques, AOFAS scores, time to return to full activity, patient satisfaction, and complication rates were extracted. The AOFAS score was the primary outcome measure. Data were synthesized, and continuous outcome measures (postoperative AOFAS score and time to return to full activity) were pooled using a random-effects inverse variance method. Random-effects meta-analysis of proportions using continuity correction methods was performed to determine the proportion of patients who were satisfied and who experienced complications.

A total of 32 studies were included in this review. No statistically significant difference was found in postoperative AOFAS scores between open surgery (88.0; 95% CI, 82.1-94.4) and endoscopic surgery (94.4; 95% CI, 93.1-95.7). There was no difference in the proportion of patients who rated their satisfaction as good or excellent, 0.91 (95% CI, 0.86-0.96) versus 0.86 (95% CI, 0.79-0.94), respectively. No significant difference in time to return to activity was found, 10.8 weeks (95% CI, 7.4-15.9 weeks) versus 8.9 weeks (95% CI, 7.6-10.4 weeks), respectively. Pooled proportions of patients with postoperative complications were 0.15 (95% CI, 0.11-0.19) for open surgery versus 0.08 (95% CI, 0.05-0.14) for endoscopic surgery. Without the poor-quality studies, this difference was statistically significant for both total and minor complications, 0.24 (95% CI, 0.14-0.35) versus 0.02 (95% CI, 0.00-0.06) and 0.14 (95% CI, 0.09-0.20) versus 0.03 (95% CI, 0.01-0.05), respectively.

We found no statistically significant difference in postoperative AOFAS scores, patient satisfaction, and return to preinjury level of activity between open and endoscopic techniques. The proportion of patients who experienced a minor complication was significantly lower with endoscopic treatment when studies of poor methodological quality were excluded.

Os trigonum can become symptomatic following acute or chronic repetitive compression of the posterior ankle. Following conservative treatment failure, removal is often warranted. Current surgical options include traditional open resection and endoscopic removal. The purpose of this article is to review a population of patients who underwent endoscopic excision of symptomatic accessory os trigonum through a posterior approach and evaluate the outcomes of the procedure.

From May 2009 to September 2018, all patients who underwent excision of a symptomatic os trigonum were reviewed. Outcomes of interest were major and minor complications and time to return to full weight-bearing activities. Postoperative protocol included 5 to 7 days non-weight-bearing and 1 to 2 weeks of protected weight-bearing followed by full release to weight-bearing activities.

Twelve patients who met the inclusion criteria were studied. Mean follow-up was 10.2 (±7.4) months with no major complications and 1 minor wound complication. Average advancement to protected weight-bearing was 7.1 days. Average return to full weight-bearing activities without restriction was 24.4 days.

The current study describes the technique and results to minimally invasive os trigonum removal with favorable postoperative outcomes. Results demonstrated minimal complications and postoperative pain, also quick return to weight-bearing and full activity.

Therapeutic, Level IV: Case series.

An os trigonum is a potential source of posterior ankle pain in dancers, often associated with flexor hallucis longus (FHL) pathology. Surgical excision is indicated on failure of nonoperative management. Options for surgical excision include open excision (via a posterolateral or posteromedial approach), subtalar arthroscopy, and posterior endoscopy. Os trigonum excision via an open posteromedial approach with concomitant FHL tenolysis/tenosynovectomy is a safe and effective method for the operative treatment of a symptomatic os trigonum that allows for identification and treatment of associated FHL pathology. The major steps in the procedure, which are demonstrated in this video article, are: (1) preoperative planning with appropriate imaging; (2) patient is positioned in a supine position with the operative extremity in figure-of-4 position; (3) a 3-cm, slightly curvilinear longitudinal incision is made midway between the posterior aspect of the medial malleolus and the anterior aspect of the Achilles tendon, over the palpated FHL tendon, and the flexor retinaculum is exposed and incised; the neurovascular bundle is retracted anteriorly, exposing the FHL tendon and sheath; (4) FHL tenolysis/tenosynovectomy is performed; (5) the FHL is retracted anteriorly and a capsulotomy is performed over the os trigonum and the os trigonum is excised; (6) the capsule is repaired and closure is performed; and (7) dressings and a CAM (controlled ankle motion) walking boot are applied. The patient begins physical therapy at 2 weeks postoperatively and may return to dance at 4 to 6 weeks postoperatively as tolerated. In our series of 40 cases, 95% of patients who desired to return to dance were able to return to their pre-injury level of dance. There were no major neurovascular complications.

Neurovascular and tendon structures are considered at risk when performing ankle arthroscopy. Injury rate and distance from portals to such structures varied in the literature. The aim of this meta-analysis is to evaluate the injury risk of these structures in terms of proximity and injury prevalence. Thirteen studies including 184 cadaveric ankle arthroscopy procedures met the inclusion criteria. The antero-central portal exhibited the highest frequencies of nerve/vessel proximity and nerve/vessel missed injuries. Weighted mean distances were as follows: 2.76 ± 2.37 mm for the superficial fibular nerve (SFN) to the antero-lateral portal, 8.13 ± 2.45 mm for the saphenous nerve to the antero-medial portal, 2.1 ± 1.7 mm for the dorsalis pedis artery (DPA) to the antero-central (AC) portal, 6.84 ± 2.59 mm for the sural nerve to the postero-lateral portal. Distances to the postero-medial portal were 7.82 ± 2.98 and 11.03 ± 3.2 mm for the posterior tibial nerve and the posterior tibial artery, respectively. A total of 14 (10.3%) nerve injuries and 17 (12.5%) missed nerve injuries with a cumulative frequency of 22.8% of nerve structure at high risk. The SFN was the most vulnerable (10.3% of injury/missed injury), and it was the closest nerve to a portal. Vascular involvement consisted of 2 (1.5%) injuries and 12 (8.8%) missed injuries with the DPA being the most vulnerable (20%) through the AC portal. Tendon injuries were found in 8.7% procedure acts. The injury rates of extra-articular structures were found to be higher than previously reported in clinical literature. Apart from clinical studies, distance to portals and missed injuries of these structures could be evaluated. This cadaveric meta-analysis yielded more accurate results over the proximity and potential injury risk of ankle noble structure and should incite surgeons for more attention during portal placement. Such anatomical meta-analyses could offer an excellent statistical model of evidence synthesis when assessing injury risk in mini-invasive surgeries.

Study Design Case report. Background An os trigonum can be a source of pain for dancers due to impingement during repetitive ankle plantar flexion movements. Following excision of an os trigonum, it is important to have a gradual, progressive return-to-dance program for optimal recovery. The purpose of this case report is to describe the postoperative management and return-to-dance progression of an adolescent dancer post os trigonum excision. Case Description An adolescent preprofessional female dancer had an extensive history of left posterior heel pain, beginning at age 8, that led to surgical removal of an os trigonum at age 15. Post surgery, the patient was seen for a total of 22 visits over the course of 20 weeks. Treatment included therapeutic exercises, neuromuscular re-education, and manual therapy. Return-to-dance tests and guidelines were used to safely progress to full, unrestricted dance participation. Outcomes The dancer had a full return of ankle range of motion, strength, and balance, improved patient-reported outcome scores, and was able to fully return to dance participation. Discussion Treating a dancer following os trigonum excision should involve a screen for hypermobility, clear communication with the dance instructor, awareness of dance-specific biomechanics, and proper reintegration into dance participation. Level of Evidence Therapy, level 5. J Orthop Sports Phys Ther 2018;48(3):194-203. Epub 7 Nov 2017. doi:10.2519/jospt.2018.7508.

Open surgical excision of the os trigonum has been the traditional treatment for posterior ankle impingement syndrome (PAIS). However, the endoscopic excision has recently become quite popular. Purpose/Hypothesis: The purpose of our study was to compare the results of endoscopic versus open excision of a symptomatic os trigonum for the treatment of PAIS in an athletic population. It was hypothesized that the endoscopic technique would be superior to the open technique regarding functional outcomes, pain, and time to return to training and the previous sports level.

Randomized controlled trial; Level of evidence, 2.

From 2008 to 2011, 52 athletes underwent a symptomatic os trigonum excision; 26 athletes had an open procedure (group A) and 26 had an endoscopic procedure (group B). The American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score and the Visual Analog Score-Foot and Ankle (VAS-FA) were obtained, and the time to return to training and to previous sports level was recorded.

Patients in group B appeared to have significant improvement of AOFAS hindfoot score compared with those in group A ( P < .05), whereas no statistical significance was found for the postoperative VAS-FA scores between the 2 groups. The mean ± SD time to return to training was 9.58 ± 3.98 weeks for group A and 4.58 ± 1.47 weeks for group B ( P < .001). The time to return to previous sports level was 11.54 ± 3.89 weeks for group A and 7.12 ± 2.25 weeks for group B ( P < .001). The overall complication rate was 23% for group A (6 cases) and 3.8% for group B (1 case).

Both the open procedure and the endoscopic approach yielded acceptable outcomes in terms of function and pain. However, complication rates were remarkably lower with endoscopic treatment, and the time to return to full activities was much shorter. Endoscopic excision of the os trigonum is a safe and effective treatment option for athletes who require early return to their previous sports level.

An os trigonum is a potential source of posterior ankle pain in dancers, often associated with flexor hallucis longus (FHL) pathology. Options for operative excision include open excision, subtalar arthroscopy, and posterior endoscopy. The purpose of this paper was to present a series of dancers who underwent excision of a symptomatic os trigonum via an open posteromedial approach.

This study is a retrospective case series of 40 ankles in 38 dancers who underwent os trigonum excision via an open posteromedial approach with FHL tenolysis between 2000 and 2013. All patients were interviewed and charts retrospectively analyzed. Collected variables included pre- and postoperative pain level, time to return to dance, and subjective satisfaction. The average age was 19.2 years; ballet was the primary dance form in 36 (95%) of patient-cases. Eight (20%) of the patient-cases were professional dancers, and 30 (75%) were students or preprofessional dancers.

Average preoperative pain level was 7.7/10, which decreased to 0.6/10 postoperatively. Seventeen (42.5%) experienced concurrent preoperation-associated FHL symptomatology, all of whom experienced relief postoperatively. The average time to return to dance was 7.9 weeks, and time to pain-free dance was 17.7 weeks. Of the 37 patient-cases desiring to return to dance, 35 (94.6%) returned to their preoperative level of dance. There were no neurovascular or other major complications. Four (10%) had minor wound complications that resolved, and 38 cases (95%) considered the procedure a success.

Open posteromedial excision of an os trigonum in dancers provided satisfactory pain relief, return to dance, and complication rates compared to other approaches, and allowed for identifying and treating any associated FHL pathology.

Level IV, retrospective case series.

Posterior ankle pain can occur for many reasons. If it is produced by forced plantarflexion of the foot, it is often a result of impingement from an enlarged posterior talar process or an os trigonum. This condition may present in an acute or chronic state. Management is initially nonoperative, but surgical treatments are available. This condition is often seen in athletes, so procedures that limit surgical trauma and allow early return to activity are ideal. An arthroscopic approach for this disorder produces good outcomes with limited complications. Understanding the indications, local anatomy, and surgical technique, allows good, reproducible outcomes.

Previous studies have compared the outcomes after open and endoscopic excision of an os trigonum in patients of mixed professions. No studies have compared the differences in outcomes between the 2 procedures in elite ballet dancers. From October 2005 to February 2010, 35 professional ballet dancers underwent excision of a symptomatic os trigonum of the ankle after a failed period of nonoperative treatment. Of the 35 patients, 13 (37.1%) underwent endoscopic excision and 22 (62.9%) open excision. We compared the outcomes, complications, and time to return to dancing. The open excision group experienced a significantly greater incidence of flexor hallucis longus tendon decompression compared with the endoscopic group. The endoscopic release group returned to full dance earlier at a mean of 9.8 (range 6.5 to 16.1) weeks and those undergoing open excision returned to full dance at a mean of 14.9 (range 9 to 20) weeks (p = .001). No major complications developed in either group, such as deep infection or nerve or vessel injury. We have concluded that both techniques are safe and effective in the treatment of symptomatic os trigonum in professional ballet dancers. Endoscopic excision of the os trigonum offers a more rapid return to full dance compared with open excision.

We introduce a novel method of combining the standard anteromedial and anterolateral approaches and dual posterolateral approaches in the arthroscopic treatment of posterior and anterior ankle impingement syndrome and compare the postoperative outcomes with conventional anteromedial/anterolateral and posteromedial/posterolateral approaches.

From January 2013 to January 2015, we treated 28 patients with posterior and anterior ankle impingement syndrome by arthroscopy. The patients were divided into the conventional group (n = 13) and the modified group (n = 15) according to the surgical approaches used in the operation. Preoperative and postoperative American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale (VAS) score, range of ankle motion, and operation time were recorded. The average follow-up was 16 months (range 6-24 months).

Posterior and anterior ankle impingement syndrome was confirmed arthroscopically in all patients. After the operation, the range of ankle motion in all patients was restored. There was no significant difference in postoperative AOFAS score, VAS score, dorsiflexion, and plantarflexion between the conventional group and the modified group. Moreover, the operation time was significantly reduced in the modified group compared with the conventional group. There was no recurrence of osteophyte and no complications such as infection, neurovascular injury, or delayed healing of surgical incision in the modified group.

Dual posterolateral approaches combined with standard anteromedial and anterolateral approaches was a novel method for arthroscopic treatment of posterior and anterior ankle impingement syndrome. It proved to be safe and effective, and significantly reduced the operation time. Reposition, repeated prep and drape, and limb distraction were avoided.

Level IV, retrospective case series.

To determine whether professional and amateur athletes showed differences in ankle function when treated with endoscopic technique for posterior ankle impingement syndrome, to verify the impact of the presence of associated lesions in clinical evolution and to assess time to return to sport (we hypothesize that time will be the only difference between groups).

Thirty-two athletes with a diagnosis of posterior impingement syndrome underwent surgery endoscopically. The American Orthopaedics Foot and Ankle Society (AOFAS) scale was used to compare functional results between amateur (15) and professional athletes (17). The satisfaction, time to return to sport, operative time, intraoperative findings and complications were evaluated, and the presence of associated injuries interfering in these results was verified.

The preoperative AOFAS score range for the professional group was 62.9 ± 14 preoperatively and 92.3 ± 7.7 postoperatively, and for the amateur group was 67.9 ± 19.7 and 94 ± 9.3. The satisfaction was excellent or good in 94 % of all cases and fair in 6%. The average time of surgery was 48.3 + 25 min. Bone involvement was present in 100% of cases and complications in three cases. Time to return to sports was similar (n.s.) in both groups, and the mean time was 15.6 ± 13.7 and 16.3 ± 9 weeks, respectively.

No significant difference regarding functional results and time to return to sports between professionals and amateur athletes operated was found. Athletes showed mainly good and excellent results and low complication rate. The presence of associated injuries did not significantly influence the results. With these results, the high-level athlete can better programme their surgeries so they can fully recover and perform better in the most important competitions.

Level III.

To report the clinical outcomes of arthroscopic excision for a symptomatic os trigonum initially viewing through the posteromedial ankle portal with the motorized instrument in the posterolateral portal.

A retrospective review of a consecutive series of patients with symptomatic os trigonum failing nonoperative management and treated with arthroscopic excision was performed. Demographic data, clinical data, American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scores, and Single Assessment Numeric Evaluation scores were obtained. Any complications and the time required to return to sports or full activities were recorded.

Twenty-four patients with an arthroscopic excision of a symptomatic os trigonum were included. There were 13 male and 11 female patients. The average age was 36.7 ± 17 years. Twenty-one isolated os trigonum excisions and 3 excisions combined with other procedures were studied. At a mean follow-up of 26 months (range, 24 to 31 months), average preoperative AOFAS scores significantly improved from 55.3 to 92.3 postoperatively (P < .0001). The preoperative AOFAS function component improved from 17.1 to 33.8 (P < .0001). The mean postoperative Single Assessment Numeric Evaluation score was 90. Patients reported full activity at an average of 1.5 months with no limitations at an average of 7.8 months after surgery. The only complication was a posterior tibial nerve calcaneal branch neurapraxia.

Arthroscopic excision in the prone position without traction of a symptomatic os trigonum viewing initially through the posteromedial portal with a high-speed burr in the posterolateral portal resulted in significantly improved AOFAS scores with a single transient neurapraxia in 24 patients. Patients returned to their normal daily activities without limitations at an average of 1.5 months.

Level IV, therapeutic case series.

Os trigonum syndrome with disease of the flexor hallucis longus tendon, so-called stenosing flexor tenosynovitis, is a common cause of posterior ankle impingement. Conservative treatment is the recommended first line of treatment, with secondary treatment options of either open or arthroscopic os trigonum excision with flexor hallucis longus retinaculum release. The arthroscopic approaches have gained popularity in the past decade because of less scarring, less postoperative pain, minimal overall morbidity, and earlier return to activities. However, comprehensive understanding of the anatomy of the posterior ankle is crucial to warrant successful outcomes and minimizing complications.

A literature review has been undertaken to assess the efficacy of management of Posterior Ankle Impingement Syndrome with an emphasis on sport. The evidence is confined to Level IV and V studies. There is a lack of prospective studies on the natural history of this condition and the outcomes of conservative treatment. Dance dominates the literature accounting for 62% of reported sports. Forty-seven papers have reported on the surgical outcomes of 905 procedures involving both open and artho-endoscopic techniques. 81% of patients required excision of osseous pathology and 42% soft-tissue problems resolving. There is a lack of standardisation of outcome reporting particularly in the open surgery group. However, the complication rates are relatively low: 3.9% for open medial, 12.7% for open lateral and 4.8% for arthro-endocopic surgery. Return to sport appears quicker for all activities in the arthro-endoscopic group but comparison of long term outcomes is more difficult with no evidence supporting superior long term results of one technique over another. Soccer players appear to return more quickly to activity than dancers.

The purpose of the current study was to clinically evaluate the diagnostic value of the new posterior impingement (PIM) view in the detection of an os trigonum, compared with the standard lateral view, using computed tomography (CT) as a reference standard.

Three observers, 2 experienced (orthopaedic surgeon and radiologist) and one inexperienced (resident), independently scored 142 radiographic images for the presence of an os trigonum. The diagnostic performance was assessed using the computed tomographic scan as the reference standard. Accuracy, sensitivity, specificity, positive predicted value (PPV), and negative predicted value (NPV) were calculated.

The PIM view had significantly superior accuracy compared with the lateral view for each observer: orthopaedic surgeon, PIM view = 90 versus lateral view = 75 (P = .013); radiologist, PIM view = 80 versus lateral view = 64 (P = .019); resident, PIM view = 90 versus lateral view = 79 (P = .039). The mean sensitivity and specificity of the lateral view for all observers was 50% and 81%, respectively. For the PIM view, this was 78% and 89%, respectively. The PPV was 50% for the lateral view and 70% for the PIM view. The NPV was 84% for the lateral view and 93% for the PIM view.

The PIM view has significantly superior diagnostic accuracy compared with the conventional lateral view in the detection of an os trigonum. In cases of symptomatic posterior ankle impingement, we advise that a PIM view be used instead of or in addition to the standard lateral view for detection of posterior talar pathologic conditions. LEVEL OF 

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.

Os trigonum syndrome is the result of an overuse injury of the posterior ankle caused by repetitive plantar flexion stress. It is predominantly seen in ballet dancers and soccer players and is primarily a clinical diagnosis of exacerbated posterior ankle pain while dancing on pointe or demi-pointe or while doing push-off maneuvers. Symptoms may improve with rest or activity modification. Imaging studies, including a lateral radiographic view of the ankle in maximal plantar flexion, will typically reveal the os trigonum between the posterior tibial lip and calcaneus. If an os trigonum is absent on radiography, an MRI may reveal scar tissue behind the posterior talus, a condition associated with similar symptoms. Os trigonum syndrome is often associated with pathology of the flexor hallucis longus tendon. Treatment begins with nonsurgical measures. In addition to physical therapy, symptomatic athletes may need surgical excision of os trigonum secondary to unavoidable plantar flexion associated with their sport. This surgery can be performed using open or arthroscopic approaches.

The purpose of this systematic review was to determine the incidence of complications after posterior hindfoot endoscopy.

Ovid/Medline and Google Scholar were systematically searched for pertinent references to be included. In addition, we hand-searched common American and European orthopaedic and podiatric surgical journals for relevant articles. Articles considered for inclusion were published in peer-reviewed journals, described complications after posterior hindfoot endoscopy using a standard 2-portal technique, and involved 25 or more patients treated.

We identified 335 potentially relevant publications, of which 5 met our inclusion criteria. A total of 452 ankles (452 patients) were included in this study. Overall, 17 complications (3.8%) occurred, with only 8 (1.8%) requiring additional treatment or operative intervention.

The endoscopic approach for the treatment of hindfoot and ankle pathology is safe with a low incidence of complications. However, additional studies with prospective designs should be undertaken to determine the long-term patient outcomes using validated scoring systems.

Level IV, systematic review of Level III and IV studies.

Hindfoot arthroscopic surgery has been described as a minimally invasive surgical treatment for posterior ankle impingement syndrome. The current article describes a systematic approach for identifying relevant hindfoot structures as well as the clinical results of a case series.

To present a structured systematic surgical approach for identifying relevant anatomic structures and abnormalities during hindfoot arthroscopic surgery. In addition, we report the clinical results of a case series.

Case series; Level of evidence, 4.

The systematic surgical approach divides the extra-articular structures of the hindfoot into quadrants as defined by the intermalleolar ligament. Twenty-two patients underwent hindfoot arthroscopic surgery for the treatment of posterior ankle impingement syndrome. The mean follow-up time was 25 months (range, 14-35 months). Standard patient-reported outcome questionnaires of the foot and ankle outcome score (FAOS) and Short Form-12 (SF-12) general health survey were administered at standard time points after surgery. Return to sporting activities was also calculated as the time period from the date of surgery until the patient was able to participate at their previous level of activity.

The mean FAOS score improved from 59 (range, 22-94) preoperatively to 86 (range, 47-100) postoperatively (P < .01). The mean SF-12 score showed similar improvement with a mean of 66 (range, 42-96) preoperatively to 86 (range, 56-98) postoperatively (P < .01). Nineteen patients reported competing at some level of athletic sport before surgery. All patients returned to their previous level of competition after surgery. The mean time to return to sporting activities was 12 weeks (range, 6-16 weeks). Two complications were reported postoperatively: 1 wound infection and 1 case of dysesthesia of the deep peroneal nerve.

Hindfoot arthroscopic surgery is a safe and effective treatment strategy for posterior ankle impingement syndrome. In addition, it allows the patients a rapid return to sporting activities.

To investigate the safety and efficiency of a 2-portal lateral (anterior and middle) approach to arthroscopic subtalar arthrodesis.

A cadaveric study was performed on 30 feet of 15 fresh cadaveric bodies (15 right and 15 left; 21 female specimens and 9 male specimens). The mean age at death was 78 ± 6.7 years. The procedure was performed with the specimen in the supine position through 2 lateral (anterior and middle) sinus tarsi portals by use of a 4.0-mm arthroscope. A 3.5-mm synovial shaver was used for debridement, and a 4.5-mm shielded bur was used to resect posterior subtalar facets. The feet were then dissected. The primary outcomes were the percentage of resected joint surface and the distances between portals and both sural and superficial peroneal nerves. The secondary outcomes were injury of sinus tarsi ligaments and lateral arterial network, calcaneofibular ligament, peroneal tendons, flexor hallucis longus tendon, and posterior tibial neurovascular bundle.

The mean percentages of resected talar and calcaneal posterior subtalar facets were 94% ± 7.2% and 91% ± 6.8%, respectively. The minimum distance of either subtalar portal to the nerves was 4 mm. No nerve injury was observed. In 28 of 30 cases, the lateral sinus tarsi arterial network was found intact. In all cases the inferior retinaculum extensor was transfixed by the portals. In all cases both cervical and interosseous talocalcaneal ligaments were found intact. In 3 cases a shaving lesion was observed on the peroneus brevis tendon.

According to this cadaveric study, more than 90% freshening of the posterior subtalar articular facets can be achieved through a 2-portal lateral (anterior and middle) approach. This technique is reproducible and safe with regard to the surrounding nerves.

The 2 lateral portals may offer a safe and effective alternative approach for arthroscopic arthrodesis of the posterior subtalar joint.

The purpose of this study was to introduce our technique of arthroscopic excision of the os trigonum in the lateral decubitus position through anterolateral, centrolateral, and posterolateral portals and also to investigate the safety and clinical results of this technique.

Between May 2007 and May 2011, 23 ankles of 23 consecutive patients underwent subtalar arthroscopic removal of the os trigonum in a lateral decubitus position. Twenty patients were male and 3 were female. All patients injured their ankles during sports activities. Mean duration of postoperative follow-up was 18 months, and no patients were lost to follow-up. Clinical evaluations were performed using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analog scale (VAS) for pain. The time to return to work and sports activities was assessed.

Average AOFAS ankle-hindfoot score increased from 71.3 (range, 59-85) preoperatively to 94.7 (range, 90-100) postoperatively, and VAS for pain decreased from 6.7 (range, 3-10) to 1.5 (range, 0-3). Average plantarflexion of the ankle increased from 28.8 degrees (range, 15-40) preoperatively to 42.5 degrees (range, 25-50) postoperatively. Mean time to resumption of sports activities was 6.7 weeks (range, 5-12). There were no major complications in any patient.

Arthroscopic excision of a symptomatic os trigonum using anterolateral, centrolateral, and posterolateral portals in the lateral decubitus position was a safe and effective technique.

Level IV, retrospective case series.

This study aims to provide an overview of both the open and endoscopic procedures used to treat posterior ankle impingement, as well as an analysis, evaluation, and comparison of their outcomes.

A systematic literature search of the Medline, Embase (Classic), and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases and the Cochrane Database of Clinical and Randomized Controlled Trials was performed. Quality of included studies was assessed by use of the Downs and Black scale.

After we reviewed 783 studies, 16 trials met the inclusion criteria. Of these trials, 6 reported on open surgical techniques and 10 evaluated endoscopic techniques. The complication rate (15.9% v 7.2%) and time to return to full activity (16.0 weeks v 11.3 weeks) differed between the 2 groups, both favoring endoscopic surgery.

Although the level of evidence of the included studies is relatively low, it can be concluded that the endoscopic technique is superior to the open procedure.

Level IV, systematic review of Level IV studies.

The diagnosis of posterior ankle impingement requires an accurate history and specific examination. Computed tomography is a useful investigation to diagnose bony impingement, especially where plain radiography and/or magnetic resonance imaging are sometimes inconclusive. Accurate ultrasound-guided steroid/anesthetic injections are useful interventions to locate the symptomatic lesions and reduce symptoms and occasionally prove curative. If surgical debridement or excision is deemed necessary, arthroscopic surgery via a posterior approach is recommended to excise impingement lesions with a quicker return to sport expected and minimal complications. Open surgical excision, however, remains a viable treatment option.

Both subtalar arthroscopic and posterior endoscopic techniques are used to treat posterior ankle impingement syndrome (PAIS). However, there have been no studies comparing the 2 procedures.

Both arthroscopic and endoscopic excisions of the os trigonum are safe and effective in treating PAIS.

Cohort study; Level of evidence, 3.

Twenty-eight patients were treated with excision of the os trigonum either by an arthroscopic (16 patients) or endoscopic (12 patients) technique. The mean patient age was 29.8 years (range, 17-55 years), and the mean follow-up period was 30 months (range, 18-58 months). Preoperative and postoperative visual analog scale (VAS) score for pain, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Maryland Foot Score (MFS) were used to analyze the functional results. Duration of surgery, time to return to sports (RTS), and patient satisfaction were evaluated as well. The size of the os trigonum was measured using T1-weighted sagittal magnetic resonance imaging (MRI). The clinical and MRI results were compared between the 2 groups.

The VAS score, AOFAS score, and MFS for both the arthroscopic group (preoperative: 6.3, 63.8, and 61.5, respectively; postoperative: 1.2, 89.9, and 89.6, respectively) and endoscopic group (preoperative: 6.7, 64.8, and 62.5, respectively; postoperative: 1.2, 89.9, and 88.4, respectively) improved significantly (P < .01). The mean surgery and RTS times were 39.4 minutes and 7.5 weeks in the arthroscopic group and 34.8 minutes and 8.0 weeks in the endoscopic group, respectively (P > .05). All patients were satisfied with the results. There were no significant differences between the 2 groups in the preoperative and postoperative VAS score, AOFAS score, or MFS (P > .05). The mean size of the os trigonum was 11.1 × 8.8 mm(2) in the arthroscopic group and 12.6 × 10.4 mm(2) in the endoscopic group, and the difference was significant (P < .05). Two patients underwent both arthroscopic and endoscopic procedures because of technical difficulty in removing the large os trigonum arthroscopically.

Both arthroscopic and posterior endoscopic excisions of the os trigonum were safe and effective in treating PAIS. The arthroscopic procedure was more demanding, especially in cases of a large os trigonum. The posterior endoscopic approach had the advantage of addressing problems in the posterior ankle joint and allowed a more extensive release of the flexor hallucis longus.

The safety of posterior ankle arthroscopy is still the subject of debate. The purpose of this study was to evaluate the anatomical relationship between the posterior portals and the neurovascular structures using magnetic resonance imaging (MRI) to determine the safety of posterior portals in posterior ankle arthroscopy.

Forty ankles from 38 patients who had undergone MRI scanning for ankle disorders were assessed (18 males, 20 females). For each ankle, the angles of the presumed position of the portals to the posterior neurovascular structures and the malleoli were measured on 4-mm proximal slices from the anterior tip of the fibula. The shortest distance from the sural nerve and the tibialis posterior neurovascular bundle to the position of the posterior portals was measured.

The average distance between the posteromedial portal and the tibialis posterior neurovascular bundle was 18 ± 3 mm, whereas the average distance between the posterolateral portal and the sural nerve was 15 ± 3 mm. In 100% of ankles, there were no neurovascular structures lying within the region between the anterior tip of fibula and the posteromedial portal or between the posterior tip of fibula and the posteromedial portal. In 32 ankles (80%), the medial neurovascular structures were present on the medial side of the line running between the anterior tip of medial malleolus and the posteromedial portal.

The posterior neurovascular structures were not in immediate proximity to where we estimated the posteromedial and posterolateral portals to be located.

The findings of the present MRI-based study suggest that arthroscopic instruments oriented toward the fibula may be safely introduced into the posterior ankle without injuring the neurovascular structures.

Posterior ankle and hindfoot arthroscopy, performed with use of posteromedial and posterolateral portals with the patient in the prone position, has become an important diagnostic and therapeutic procedure for various intra-articular and extra-articular disorders.

If you are planning to use fluoroscopy for surgery and wire distraction, position the patient prone, flex the contralateral knee, and wrap the contralateral leg to a padded holder.

Invasive distraction is used primarily to improve access to the ankle and subtalar joints.

Using a mini-c-arm fluoroscopy unit to guide portal placement, place the posterolateral and posteromedial portals just lateral and medial to the Achilles tendon.

Specific procedures include posterior arthroscopic arthrodesis of the subtalar joint, ankle arthrodesis, and excision of the os trigonum with tenolysis of the flexor hallucis longus tendon.

Close the skin incision with nonabsorbable nylon sutures, and apply a sterile bulky dressing.

Postoperatively, a plaster splint or walking boot with the foot in neutral is used for the first five to seven days.

Posterior ankle and hindfoot arthroscopy was performed in 189 ankles (186 consecutive patients with a mean age of 37.1 years).

IndicationsContraindicationsPitfalls & Challenges.

The aim of this study was to investigate the outcome after arthroscopic procedures for treatment of posterior ankle impingement.

From June 2006 to April 2009 36 patients were treated by hindfoot arthroscopy. Indication was posterior ankle impingement due to symptomatic os trigonum or osteophytes. Pain on the VAS was evaluated pre- and postoperatively. Minimum follow-up was 6 months.

30 patients were available for follow-up. Follow-up averaged 9.7 months (range 6-14 months). Pain measured on the VAS improved significantly from 7.2 points to 1.3 points. One superficial (3.3%) and one deep wound infection (3.3%) occurred, 6.6% of our patients complained about impaired sensitivity of the sural nerve, and 6.6% required resurgery.

Hindfoot arthroscopy is an elegant surgical technique in treatment of posterior ankle impingement. The minimally invasive procedure allows for low complication rates.

Subtalar joint arthroscopy can be performed on a wide array of pathology. The procedure has progressed from a diagnostic test to a reconstructive procedure. Although it is not as popular as ankle arthroscopy, it is becoming more commonly discussed in the literature and is part of many arthroscopy courses. Better education along with improved instrumentation will allow more foot and ankle surgeons to treat pathology of the subtalar joint with arthroscopic techniques. This will lead to improved outcomes and lower complication rates in treating that pathology.

We treated 12 cases of posterior ankle bony impingement in 12 athletes arthroscopically, and examined the operating methods, findings, and postoperative physical therapy and overall results.

The patients' average age was 21.4 years. The mean duration of postoperative followup was 33.8 months. A 2.7-mm, 30 degree arthroscope was inserted into the subtalar joint using posterolateral and accessory posterolateral portals. When the impinged fragment was visualized, it was carefully excised from the surrounding soft tissues. The operation was completed once the entire flexor hallucis longus tendon was seen. No cast immobilization was applied postoperatively, and physical therapy including limited weight bearing and range-of-motion exercises commenced within 24 hours after surgery. Beginning 3 weeks after surgery, the patients were permitted to gradually resume sports under the guidance of a physiotherapist. The AOFAS ankle-hindfoot score, the postoperative range of motion of the ankle and the time to recover were determined.

The average postoperative AOFAS ankle-hindfoot score improved from 68.0 to 98.3 points. The mean preoperative range of motion of the ankle joint was improved from 59.2 degree to 68.4 degree. The average period to return to sports was 5.9 weeks. All patients reached full activity within 13 weeks after surgery. The surgical time ranged from 40 minutes to over 2 hours and was affected by the impingement condition.

Arthroscopic treatment for posterior ankle bony impingement syndrome was minimally invasive and suitable for athletes who desire an early return to sports activity.

To compare the clinical results of a consecutive series of 43 cases of excision of a symptomatic os trigonum performed with an open versus hindfoot endoscopic technique.

From 1994 to 2007, 43 patients underwent a symptomatic os trigonum excision. A subjective satisfaction questionnaire and a visual analog scale score for pain were obtained, and the American Orthopaedic Foot & Ankle Society ankle and hindfoot score and the time to return to previous sports level were determined in 41 of 43 patients at follow up. Of the ankles, 16 had an open os trigonum excision and 25 had hindfoot endoscopic surgery. Group A (16 ankles, open surgery) and group B (25 ankles, endoscopic excision) were comparable concerning age, sex, profession, and concomitant injury of the ankle.

At follow-up evaluation (12 to 86 months after surgery), group B had a significantly shorter mean time to return to previous sports level. There was no difference in postoperative visual analog scale score, American Orthopaedic Foot & Ankle Society score, subjective satisfaction rating, or rating of sensory nerve loss between the 2 groups.

Both open surgery and hindfoot endoscopic excision of a symptomatic os trigonum were effective and safe. Patients with an endoscopic excision had a shorter time to return to previous sports level.

Level IV, therapeutic case series.