Imaging of Ankle Impingement Syndromes

Os Trigonum Syndrome: A Cause of Posterior Ankle Pain

BACKGROUND

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.

MATERIALS AND METHODS

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".

RESULTS

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.

CONCLUSION

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.].

The Aggressive Open Anterior Ankle Cheilectomy as Joint Salvage for Anterior Ankle Impingement Syndrome and Arthritis

Anterior ankle impingement syndrome can frequently present in athletes and post-traumatic patients who have osteophytes contributing to limited dorsiflexion and pain. Surgical treatment options include arthroscopy, open arthrotomy, arthrodesis, and total implant arthroplasty. For many, joint-sparing arthroscopy or arthrotomy yield satisfactory results if significant debridement is performed. If debridement is not aggressive, patients may not obtain the desired improvement. In cases where a larger amount of bone must be removed, or the patient does not have an anatomic appearing talar neck due to osteophytic changes, we have found that an open approach is necessary to achieve good results. To the best of our knowledge, no such technique has been previously published detailing a standard approach to open ankle arthrotomy. Our technique is coined the "Aggressive Open Anterior Ankle Cheilectomy" and involves a systematic 3-step approach. First, the tibial osteophytes are resected with an osteotome; second, the ankle gutters are addressed, and all hypertrophic bones removed; and third, an anatomic talar neck is fashioned. We herein describe our surgical technique and case examples.Level of Evidence: 5.

Can ultrasound replace MRI in diagnosing causes of ankle impingement in different compartments?

PURPOSE

This prospective study aims to determine the role of ultrasound (US) in diagnosing different types of ankle impingement due to osseous and soft tissue pathologies and to compare the results with magnetic resonance imaging (MRI), which is considered our gold standard.

METHODS

The study population included 90 patients with unilateral ankle pain who presented with symptoms and signs suggestive of ankle impingement. Their age ranged from 17 to 57 years, with a mean age of 33.7 years. Using US and MRI, our cases were classified into bony and soft tissue ankle impingement. They were further classified according to the anatomical compartments affected, into anteromedial, anterior, anterolateral, posteromedial, and posterior.

RESULTS

90 patients were enrolled in this study: 51 males and 39 females. In our study, posterior ankle impingement was the commonest impingement type, while anteromedial ankle impingement was the rarest type, followed by posteromedial impingement. The accuracy of US in diagnosing osseous impingement was found to have the following: sensitivity 70.37%, specificity 100%, PPV 100%, NPV 75%, accuracy 84.31%, and p value < 0.001; meanwhile, the accuracy of US in diagnosing soft tissue impingement was found to have the following: sensitivity 83.33%, specificity 100%, PPV 100%, NPV 87.10%, accuracy 92.16%, and p value < 0.001.

CONCLUSION

US is a good diagnostic tool in bone and soft tissue impingements, with a significant p value of 0.001 for both. US cannot replace MRI as a diagnostic tool, but as a widely available imaging modality, it can save time and cost and allows dynamic imaging.

Arthroscopic treatment of ankle impingement syndrome

Arthroscopic treatment of ankle impingement syndrome (AIS) is a minimally invasive surgical procedure used to address symptoms caused by impingement in the ankle joint. This syndrome occurs when there is abnormal contact between certain bones or soft tissues in the ankle, leading to pain, swelling, or limited range of motion. Traditionally, open surgery was the standard approach for treating AIS. However, with advancements in technology and surgical techniques, arthroscopic treatment has become a preferred method for many patients and surgeons. With improved visualization and precise treatment of the arthroscopy, patients can experience reduced pain and improved functionality, allowing them to return to their daily activities sooner. In this paper, we reviewed the application and clinical efficacy the of arthroscopic approach for treating AIS, hoping to provide a reference for its future promotion.

Arthroscopic Treatment of Anterior Ankle Impingement

Arthroscopic reduction of tibiotalar osteophytes results in good to excellent results in the vast majority of patients. Pain is primarily due to synovial hypertrophy and anterior tibiotalar entrapment associated with the osteophytes. Osteophytes may be due to repetitive trauma such as sports, or associated with subtle or overt ankle instability. A minimally invasive approach results in rapid recovery and less risk than open interventions. In cases where anterior osteophytes have coexisting ankle instability and in many cases ancillary procedures such as ankle stabilization are performed.

Ankle Instability Update

Sprains are the most frequent injuries of the ankle, especially in sports. Up to 85% of cases affect the lateral ligament complex. Multi-ligament injuries with associated lesions of the external complex, deltoid, syndesmosis, and sinus tarsi ligaments are also common. Most ankle sprains respond to conservative treatment. However, up to 20 to 30% of patients can develop chronic ankle pain and instability.New concepts have been recently developed, based on arthroscopic advances, such as microinstability and rotatory ankle instability. These entities could be precursors of mechanical ankle instability and at the origin of frequently associated ankle injuries, such as peroneus tendon lesions, impingement syndromes, or osteochondral lesions.Imaging methods, especially magnetic resonance (MR) imaging and MR arthrography, are key in precisely diagnosing ligament lesions and associated injuries, facilitating an adequate therapeutic approach.

CT-Based Calculation Model Assists Precise Treatment for Anterior and Posterior Ankle Bony Impingement

OBJECTIVE

Ankle arthroscope is the preferred tool for ankle surgeons to treat ankle impingement. However, there is no relevant report on how to improve the accuracy of arthroscopic osteotomy through preoperative planning. The aims of this study were to investigate a novel method to obtain the bone morphology in anterior and posterior ankle bony impingement through computed tomography (CT) calculation model, use this method to guide surgical decision-making, and compare the postoperative efficacy and actual bone cutting volume with conventional surgery.

METHODS

This retrospective cohort study includes 32 consecutive cases with anterior and posterior ankle bony impingement by arthroscopy from January 2017 to December 2019. Mimics software was utilized to calculate the bony morphology and measure the volume of the osteophytes by two trained software engineers. The patients were divided into the precise group (n = 15) and the conventional group (n = 17) according to whether obtain and quantify the osteophytes' morphology with CT based calculation model preoperative. All patients were evaluated clinically using visual analog scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, active dorsiflexion and plantarflexion angle before and after surgery at both 3 months and 12 months postoperatively. We obtained the shape and volume of bone cutting through Boolean calculation. Clinical outcomes and radiological data were compared between the two groups.

RESULTS

The VAS score, AOFAS score, active dorsiflexion angle and plantarflexion angle were significantly improved in both groups postoperatively. In comparison of the VAS score, AOFAS score, and active dorsiflexion angle, the precise group were higher than the conventional group in the follow-up at 3 and 12 months postoperatively with statistical difference. The difference between the virtual bone cutting volume and the actual bone cutting volume of the anterior edge of distal tibia in the conventional group and precise group were 244.20 ± 147.66 mm³ and 76.53 ± 168.51 mm³ , respectively, there was statistical difference between the two groups (t = -2.927, p = 0.011).

CONCLUSION

Using a novel method of obtaining and quantifying the bony morphology with CT-based calculation model for anterior and posterior ankle bony impingement can help guide surgical decision-making preoperatively and assist precise bone cutting during the operation, which can improve the efficacy and evaluate the accuracy of osteotomy postoperatively.

Causes of delayed diagnosis of posterior ankle impingement in the pediatric and adolescent population

PURPOSE

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).

CONCLUSION

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.

Delayed diagnosis of posterior ankle impingement in pediatric and adolescent patients: does radiology play a role?

BACKGROUND

Posterior ankle impingement syndrome (PAIS) results from the pinching of anatomical structures in the posterior part of the ankle.

OBJECTIVE

To identify the possible role of imaging in the delayed diagnosis of PAIS and identify key findings on imaging to suggest PAIS in pediatric and adolescent patients.

MATERIALS AND METHODS

Data were collected prospectively in patients younger than 18 years of age who underwent arthroscopy after being diagnosed with PAIS. Imaging was reviewed retrospectively by two radiologists, compared with findings in literature and an age-matched control group, and correlated with arthroscopic findings. Pre- and postsurgical Visual Analogue Scale (VAS) pain and American Orthopedic Foot Ankle Society (AOFAS) ankle-hindfoot scores were noted.

RESULTS

Thirty-eight patients (20 females, 18 males), 51 ankles, with an average age of 12.9 years had an average 18-month delay in diagnosis. Twenty-seven of the 38 (73%) patients had previously seen multiple medical providers and were given multiple misdiagnoses. Radiographs were reported normal in 34/47 (72%) ankles. Thirty patients had magnetic resonance imaging (MRI) and findings included the presence of an os trigonum/Stieda process (94%) with associated osseous edema (69%), flexor hallucis longus (FHL) tenosynovitis (16%), and edema in Kager's fat pad (63%). Although individual findings were noted, the impression in the MRI reports in 16/32 (50%) did not mention PAIS as the likely diagnosis. There was a significant difference in the MRI findings of ankle impingement in the patient population when compared to the control group. Surgery was indicated after conservative treatment failed. All 51 ankles had a PAIS diagnosis confirmed during arthroscopy. At an average follow-up of 10.2 months, there was improvement of VAS pain (7.0 to 1.1) and AOFAS ankle-hindfoot scores (65.1 to 93.5).

CONCLUSION

PAIS as a diagnosis is commonly delayed clinically in young patients with radiologic misinterpretation being a contributing factor. Increased awareness about this condition is needed among radiologists and physicians treating young athletes.

Posterior ankle impingement–an underdiagnosed cause of ankle pain in pediatric patients

BACKGROUND

Posterior ankle impingement syndrome (PAIS) is a cause of ankle pain due to pinching of bony or soft tissue structures in the hindfoot. The diagnosis is primarily made based on detailed history and accurate clinical examination. The delay in its diagnosis has not yet been described in the pediatric and adolescent population.

AIM

To identify and characterize misdiagnosed cases of PAIS in pediatric and adolescent patients.

METHODS

This descriptive prospective study at a tertiary children’s hospital included patients ≤ 18 years who underwent posterior ankle arthroscopy after presenting with chronic posterior ankle pain after being diagnosed with PAIS. Collected data included: Demographics, prior diagnoses and treatments, providers seen, time to diagnosis from presentation, and prior imaging obtained. Visual Analogue Scale (VAS) for pain and American Orthopedic Foot Ankle Society (AOFAS) ankle-hindfoot scores were noted at initial presentation and follow-up.

RESULTS

35 patients (46 ankles) with average age of 13 years had an average 19 mo (range 0-60 mo) delay in diagnosis from initial presentation. 25 (71%) patients had previously seen multiple medical providers and were given multiple other diagnoses. All 46 (100%) ankles had tenderness to palpation over the posterior ankle joint. Radiographs were reported normal in 31/42 (72%) exams. In 32 ankles who underwent MRI, the most common findings included os trigonum (47%)/Stieda process (47%). Conservative treatment had already been attempted in all patients. Ankle impingement pathology was confirmed during arthroscopy in 46 (100%) ankles. At an average follow-up of 13.1 mo, there was an improvement of VAS (pre-op 7.0 to post-op 1.2) and AOFAS scores (pre-op 65.1 to post-op 94).

CONCLUSION

This is the first study which shows that PAIS is a clinically misdiagnosed cause of posterior ankle pain in pediatric and adolescent population; an increased awareness about this diagnosis is needed amongst providers treating young patients.

Evaluation of the Prevalence of Os Trigonum and Talus Osteochondral Lesions in Ankle Magnetic Resonance Imaging of Patients With Ankle Impingement Syndrome

The prevalence of os trigonum and osteochondral lesions of talus (OCLT) have been presented in different prevalences among different groups in the literature for the patients with ankle impingement syndrome. Our main objective in the study was to determine the possible relationship between the impingement syndrome and the prevalence of os trigonum and OCLT in specific groups. The presence of anterior ankle impingement syndrome (AAIS), posterior ankle impingement syndrome (PAIS), os trigonum, OCLT, and the location of OCLT were evaluated in a blinded manner on magnetic resonance imaging from patients clinically considered to be diagnosed with ankle impingement syndrome from January 2014 to July 2017. The patients were separated into specific groups according to the confirmation of their clinical diagnosis of ankle impingement syndrome on magnetic resonance imaging . A total of 333 patients were included. The prevalence of os trigonum was found to be 1.3% in patients with PAIS(-) AAIS(+), 7.7% in patients with PAIS(-) AAIS(-), 63.3% in patients with PAIS(+) AAIS(-), and 81.1% in patients with PAIS(+) AAIS(+) (p < .001). The prevalence of OCLT was found to be 41.3% in patients with PAIS(-) AAIS(+), 23.1% in patients with PAIS(-) AAIS(-), 18.3% in patients with PAIS(+) AAIS(-), and 27% in patients with PAIS(+) AAIS(+) (p= .005). Our study showed that, for patients with isolated PAIS and AAIS combined with PAIS, the prevalence of os trigonum was 63.3% and 81.1%, respectively, which is more common than previously reported. For patients with isolated AAIS and PAIS, the prevalence of OCLT was 41.3% and 18.3%, respectively. Of the OCLTs combined with ankle impingement syndromes, 87.1% were medially located.