UNASSIGNED: Os trigonum and Stieda process are common etiologies for posterior ankle impingement syndrome (PAIS), and diagnosis is typically made by radiographs, computed tomographic, or magnetic resonance imaging. However, these static tests may not detect associated soft tissue and bony pathologies. Posterior ankle and hindfoot arthroscopy (PAHA) is dynamic, providing at least ×8 magnification with full anatomical visualization. The primary aim of this study was to report the prevalence of associated conditions seen with trigonal impingement treated with PAHA.
UNASSIGNED: In this retrospective comparative study, patients who underwent PAHA for PAIS due to trigonal impingement, from January 2011 to September 2016, were reviewed. Concomitant open posterior procedures and other indications for PAHA were excluded. Demographic data were collected with pre- and postoperative diagnosis, arthroscopic findings, type of impingement, location, associated procedures, and anatomical etiologies. Trigonal impingements were divided in os trigonal or Stieda and subgrouped as isolated, with flexor hallucis longus (FHL) disorders, with FHL plus other impingement, and with other impingement lesions.
UNASSIGNED: A total of 111 ankles were studied-74 os trigonum and 37 Stieda. Isolated trigonal disorders accounted for 15.3% of PAIS (n = 17). Cases having associated conditions had a mode of 3 additional pathologies. FHL disorders were found in 69.4%, subtalar impingement in 32.4%, posteromedial ankle synovitis in 25.2%, posterolateral ankle synovitis in 22.5%, and posterior inferior tibiofibular ligament impingement in 19.8% of cases. Associated pathologies were observed in 58.6% of cases when FHL was not considered. Significant differences were noted comparing os and Stieda (isolated: 20.3% to 5.4%, P = .040; FHL plus others: 35.1% to 59.5%, P = .015).
UNASSIGNED: Trigonal bone (os trigonum or Stieda) was found to cause impingement in isolation in a small proportion of cases even when the FHL was considered part of the same disease spectrum. This should alert surgeons when considering removing trigonal impingement. Open approaches may limit the visualization and assessment of associated posterior ankle and subtalar pathoanatomy, thus possibly overlooking concomitant causes of PAIS.
UNASSIGNED: Level III, retrospective comparative study.

UNASSIGNED: 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.
UNASSIGNED: To examine patient outcomes, return to sport, and complications associated with MIS for a symptomatic os trigonum.
UNASSIGNED: Systematic review; Level of evidence, 4.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

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.

OBJECTIVE: To study the epidemiology and return to play characteristics of anterior and posterior ankle impingement syndromes (AAIS and PAIS) over 18 consecutive seasons in male professional soccer players.
METHODS: Between the 2001-2002 and 2018-2019 seasons, 120 European soccer teams were followed prospectively for various seasons. Time loss injuries and player exposures were recorded individually in 6754 unique players. Injury incidence and burden were reported as the number of injuries and days absence per 1000 h with 95% confidence intervals (CIs). Injury severity was reported as median absence in days with the interquartile range (IQR).
RESULTS: Out of 25,462 reported injuries, 93 (0.4%) were diagnosed as AAIS (38%) or PAIS (62%) in 77 players. AAIS and PAIS were similar regarding injury characteristics except for a greater proportion of AAIS having a gradual onset (69% vs.47%; P = 0.03) and being re-injuries (31% vs. 9%; P = 0.01). Impingement syndromes resulted in an overall incidence of 0.03 injuries (95% CI 0.02-0.03) per 1000 h and an injury burden of 0.4 absence days per 1000 h. PAIS incidence was significantly higher than that for AAIS [0.02 (95% CI 0.002-0.03) vs. 0.01 (95% CI 0.005-0.01) injuries per 1000 h (RR = 1.7). The absence was significantly longer in AAIS than in PAIS [10 (22) vs. 6 (11) days; P = 0.023]. Impingement syndromes that presented with a gradual onset had longer absences in comparison to impingement with an acute onset [8 (22) vs. 5 (11) days; P = 0.014]. Match play was associated with a higher incidence and greater injury burden than training: 0.08 vs. 0.02 injuries per 1000 h (RR 4.7), respectively, and 0.9 vs. 0.3 days absence per 1000 h (RR 2.5).
CONCLUSIONS: Ankle injuries are frequent in men\'s professional soccer and ankle impingement is increasingly recognized as a common source of pain, limited range of motion, and potential time loss. In our study, ankle impingement was the cause of time loss in less than 0.5% of all injuries. PAIS was more frequently reported than AAIS, but AAIS was associated with more absence days and a higher re-injury rate than PAIS. The findings in this study can assist the physician in best practice management on ankle impingment syndromes in professional football.
METHODS: II.

UNASSIGNED: The os trigonum is a common cause of posterior ankle impingement in children and adults. Its incidence in the medical literature is controversial. The aim of the study is to determine the incidence of os trigonum, medullary imaging features and size in pediatric patients with suspected posterior ankle impingement.
UNASSIGNED: Fifty-five children (4-16-years-old; 16 girls,) who underwent magnetic resonance ımaging (MRI) with a pre-diagnosis of posterior ankle impingement syndrome (PAIS) were included in the study. Their ankle MRI and lateral radiograms were retrospectively reviewed. The relationship between os trigonum type, size, medullary signal characteristics, and PAIS development was investigated. Skeletal maturity was graded based on the ossification pattern of the calcaneal apophysis. The possible relationship between skeletal maturity and PAIS caused by os trigonum was investigated.
UNASSIGNED: Among the 55 participants, there were 14 participants diagnosed with PAIS (9 boys, mean age 15±1.2 years). There was no connection between the os trigonum type, its medullary signal, gender, and PAIS clinical picture (p>0.05). The os trigonum size causing PAIS was 9±3.4 mm on average. There was a statistically significant relationship between PAIS complaints and os trigonum size (p=0.04). There was no significant relationship between calcaneal stage and PAIS clinical picture (p=0.669). When the os trigonum was fused, all participants were at calcaneal stage 3 or higher.
UNASSIGNED: MRI is superior in detecting fusion of the os trigonum with the talus, the medullary signal of ossicle, and PAIS findings. The most important factor in the development of PAIS is the size of the os trigonum.

BACKGROUND: A common cause of posterior ankle pain is posterior ankle impingement syndrome (PAIS). Many studies about PAIS have been conducted on special groups such as athletes and dancers; there has been no previous study of a nonathletic population. This study aimed to evaluate the causes and treatment methods of PAIS in the nonathletic population and compare it with the athletic population.
METHODS: A retrospective review was performed and 28 of 46 patients (60.9%) recovered from two-staged conservative therapy. In the 18 patients (39.1%) who did not benefit from 3 months of conservative treatment, hindfoot endoscopy was applied. Patient data, including sex, age, occupation, and sports activity level, were recorded. Visual analog scale, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot, and Tegner scores were recorded. Patient satisfaction was assessed with a 4-point Likert scale. Complications were recorded.
RESULTS: Mean follow-up was 27.4 months. At final follow-up, the AOFAS hindfoot score had significantly improved from 66.4 to 96.8 (P < .001). The Tegner score improved significantly from 4.6 to 8.8 (P < .001). The visual analog scale score was 6.4 and increased to 0.9 (P < .001). Using the 4-point Likert scale for patient satisfaction, 13 (72.2%) stated that the surgical procedure was excellent and five (27.8%) good. Mean time to return to work was 4.2 weeks. Sural nerve dysesthesia was seen in two patients (11.1%).
CONCLUSIONS: This is the first study to evaluate PAIS in the nonathletic population. Conservative treatment showed good results as nearly two-thirds of the patients recovered. Hindfoot endoscopy in those not responding to conservative therapy is a successful treatment with low complication rates.

OBJECTIVE: The purpose of this study was to identify and characterize various causes of delay in the diagnosis of posterior ankle impingement syndrome (PAIS) in pediatric patients.
METHODS: IRB approved prospective study of patients under 18 years who underwent arthroscopic surgery for the diagnosis of posterior ankle impingement after failed conservative treatment at a tertiary children\'s hospital. Radiographic findings were compared with an age-matched control group. Descriptive and inferential statistics were employed.
RESULTS: 47 patients (61 ankles), mean age 13 years, had an average 14 months delay in diagnosis of PAIS from the initial presentation. 33 (70%) patients had seen multiple medical providers and given other diagnoses. 9 (19%) patients participated in ballet or soccer, and 16 (34%) patients had unrelated associated foot and ankle diagnoses. 25 (41%) of 61 ankles did not have pain on forced plantar flexion; all 61(100%) ankles had tenderness to palpation over the posterior ankle joint line. Radiographs were reported to be normal in 37/52 (71%) ankles, while MRI report did not mention the diagnosis in 20/41 (49%) studies. There was a significant difference in the MRI findings in the patient population when compared to the control group. Indication for surgery was failed conservative treatment. All 61 ankles had posterior ankle impingement pathology confirmed visually during arthroscopy. At average 15 months follow-up, there was significant improvement pre- to post-operatively (p<0.001) for both pain VAS (6.9-0.9) and AOFAS ankle-hindfoot scores (65-94).
CONCLUSIONS: Multiple clinical and imaging factors can lead to delayed diagnosis of posterior ankle impingement. An increased awareness about the features of PAIS is needed amongst medical providers involved in treating young patients.

Posterior ankle pain is a common complaint, and the potential causative pathologic processes are diverse. The constellation of these numerous etiologies has been collectively referred to as posterior ankle impingement syndrome. The pain associated with posterior ankle impingement is caused by bony or soft tissue impingement of the posterior ankle while in terminal plantar flexion. This condition is most frequently encountered in athletes who participate in sports that involve forceful, or repetitive, ankle plantar flexion. This article discusses the associated pathology, diagnosis, conservative treatment, and surgical techniques associated with flexor hallucis longus and posterior ankle impingement syndrome.

UNASSIGNED: Management of ankle pain in dancers can be challenging because of the repetitive stress and complex demands placed on this region. Despite the prevalence of ankle injuries in this population, literature on surgical outcomes and return to dance is limited.
UNASSIGNED: To retrospectively evaluate the efficacy and functional outcomes after surgical excision of a symptomatic os trigonum in dancers.
UNASSIGNED: Case series; Level of evidence, 4.
UNASSIGNED: Between June 2006 and June 2016, a total of 44 dancers underwent surgical excision of a symptomatic os trigonum at a single institution and by a single surgeon. All patients presented with symptoms of posterior ankle impingement syndrome and subsequently failed nonsurgical treatment. Clinical analysis was conducted using various pre- and postoperative patient-reported outcome questionnaires, including the Veterans RAND 12-Item Health Survey (VR-12), Foot Function Index-Revised (FFI-R), and visual analog scale (VAS) for pain, as well as subjective patient satisfaction.
UNASSIGNED: A total of 44 patients (54 ankles; mean age, 18.2 years) were retrospectively evaluated at a mean follow-up of 33.4 months. The VR-12 Physical Health score improved from a mean score of 37.8 ± 11.9 to 51.2 ± 10.5 (P < .001). The cumulative FFI-R score improved from 46.45 ± 13.8 to 31.2 ± 9.7 (P = .044), with the subcategory of \"activity limitation\" representing the highest-scoring FFI-R subcategory at 65.28 ± 13.4 preoperatively and improving to 34.47 ± 12.4 at follow-up (P < .001). The mean VAS score for subjective pain improved significantly from 5.39 ± 2.84 to 1.73 ± 2.10 (P < .00044).
UNASSIGNED: Overall, the findings of the present study demonstrate that dancers of varying style and level improved significantly according to various clinical measures. Patients included in this study reported that they returned to their previous level of dance upon completion of physical therapy and maintained thriving postoperative careers, which for several meant dancing at the professional level.

Posterior ankle impingement is a cause of posterior ankle pain common in those who perform frequent plantarflexion activities. Three young patients presented with posterior ankle pain which was initially attributed to peroneal tendon subluxation. However, detailed physical exam and imaging confirmed the diagnosis of posterior ankle impingement as the actual cause of pain. The peroneal tendon subluxation was not causal but an unrelated co-incidental finding. After failed prolonged conservative management (rest, immobilization and physical therapy), the patients underwent posterior ankle arthroscopic debridement for the impingement resulting in return to prior sporting activity without limitation and no recurrence of pain at 19 months follow-up. Posterior ankle impingement diagnosis could be masked by co-incidental asymptomatic peroneal tendon subluxation in pediatric patients.