Disorders of the Flexor Hallucis Longus and Os Trigonum

Os trigonum: a discussion of its role in posterior ankle impingement syndrome and a meta-analysis of its prevalence

PURPOSE

the os trigonum is a supernumerary bone that may lead to posterior ankle impingement syndrome. The present study aims to assess the prevalence of this bone.

METHODS

A meta-analysis regarding the presence of the os trigonum was performed. For this, the MEDLINE and SciElo databases were searched using "os trigonum" as the keyword. Only original articles, theses, books, dissertations, and monographs were included. Papers with a sample size of < 50 individuals were excluded. The data extracted from the articles were: the total sample size, the prevalence of the trigonum, the method of analysis, the region of the sample, and data regarding sex and side (left or right). Statistical analysis was performed using MedCalc Statistical Software version 14.8.1 (MedCalc Software bvba, Ostend, Belgium). The heterogeneity between the studies was assessed using the I² estimation and the Cochran Q test. For all analyses, a random effect was used and a value of p < 0.05 was considered significant.

RESULTS

249 papers were found, while 18 were included in the meta-analysis. A total of 17,626 ankles were included. The pooled prevalence of the os trigonum was 10.3% (95% CI 7-14.1%) in the present study. There was no significant difference regarding sex or side, while studies conducted in imaging exams showed a higher prevalence in comparison to cadaveric studies.

CONCLUSION

Our results suggest that the os trigonum is relatively common. Knowledge of the prevalence of the os trigonum may help surgeons and clinicians diagnose posterior ankle impingement syndrome.

Bilateral Os Trigonum Fracture Treated With Simultaneous Posterior Ankle Arthroscopy

This is a case report of a 21-year-old female undergraduate student who sustained bilateral ankle injuries while jumping from a moving van wearing 3-inch high heel shoes. Upon initial presentation, her injury was treated conservatively as an acute bilateral ankle sprain for 6 weeks. However, the patient reported no improvement of pain and remained unable to self-ambulate. Bilateral MRI and CT scans of both ankles demonstrated bilateral os trigonum fractures. She underwent bilateral posterior ankle arthroscopic débridement of both os trigonum. At the postoperative 36-month follow-up, the patient reported notable improvement of all functional outcomes (36-item Short Form survey and Foot and Ankle Ability Measure), reported return to the same level of sports activities, and experienced no pain (visual analog scale) on either ankle. This is the first report in the literature of bilateral os trigonum fracture treated with simultaneous posterior ankle arthroscopic débridement.

Presurgical Perspective and Postsurgical Evaluation of Non-Achilles Tendons of the Ankle and Retinaculum

The vast majority of non-Achilles ankle tendinopathies are related to overuse. This article discusses the clinical aspect, imaging appearance, and management of tendinopathies of the lateral, medial, and the anterior compartments with a focus on presurgical perspective and postsurgical evaluation.

The coexistence of os trigonum, accessory navicular bone and os peroneum and associated tendon and bone pathologies

PURPOSE

To determine how often os trigonum is accompanied by accessory navicular and os peroneum. A secondary aim of the study was to investigate the bone and related tendon pathologies that may develop in these three accessory bones.

MATERIALS AND METHODS

A total of 110 patients who were evaluated by ankle MRI and were determined with os trigonum between 2009-2015 were included in the study. The frequency was determined of os trigonum together with accessory navicular bone and os peroneum. MR images were also evaluated in respect of bone pathologies and related tendon pathologies of these 3 accessory bones.

RESULTS

Of 110 patients determined with os trigonum on MRI, 21 (19%) were also determined with accessory navicular bone and 5 (4.5%) with os peroneum.When bone pathologies were examined, the most frequently seen pathology was bone marrow edema.The most common pathology in the tendons related to the accessory bones was increased amount of synovial fluid within the tendon sheath. In cases with os trigonum, bone changes were observed more frequently than pathologies of the adjacent tendons, in the accessory navicular bone cases, tendon pathologies were observed more than bone changes and in the cases with os peroneum, bone and tendon pathologies were determined at equal rates.There was no significant difference in terms of FHL tendon pathology between patients with and without edema in os trigonum. However, TP tendon was significantly more pathological in patients with edema in accessory navicular bone.

CONCLUSION

More than one accessory bone was determined in approximately one in four cases.The most common pathologies determined in these accessory bones was bone marrow edema and increased amount of synovial fluid within the tendon sheath.It is necessary to investigate and report all these findings on MRI as they play an important role in the explanation of clinical findings and treatment planning.

What Is the Efficacy of a Nonoperative Program Including a Specific Stretching Protocol for Flexor Hallucis Longus Tendonitis?

BACKGROUND

Diagnosis and treatment of tendonitis/entrapment of the flexor hallucis longus (FHL) has been sporadically described in the evidence, primarily in the context of dancers and other athletes. Although various nonspecific nonoperative treatments have been described, it is not clear how often they achieve a satisfactory amount of symptom improvement.

QUESTIONS/PURPOSES

The present study was designed to address the following questions regarding the nonoperative treatment of FHL tendonitis: (1) In a population of patients where the default management option for FHL tendonitis is a comprehensive nonsurgical approach, what proportion of patients thus treated opted not to have surgery? (2) What factors were associated with a patient's decision to undergo surgery after a period of nonsurgical management?

METHODS

The 656 patients included were all those diagnosed with FHL tendonitis who were initially treated nonoperatively in the foot and ankle division between January 2009 and December 2018. Demographics, comorbidities, examination findings, imaging results, pain scores, treatment instituted, and final outcome were obtained from the electronic medical record. The primary outcome was the decision to have surgery due to unsatisfactory symptom improvement. We compared patients who opted for surgery with those who did not after nonoperative treatment with univariable and multivariable statistics using demographics, comorbidities, and clinical findings as potential risk factors, with p < 0.05.

RESULTS

Forty-four percent (180 of 409) of patients decided to forgo surgery after the institution of a specific FHL stretching program. Surgery was more likely in patients with clinical hallux rigidus (OR 2.4 [95% CI 1.16 to 4.97]; p = 0.02) or posteromedial ankle pain (OR 1.78 [95% CI 1.12 to 2.83]; p = 0.01) and less likely in those who completed an FHL stretching program (OR 0.15 [95% CI 0.08 to 0.27]; p < 0.001).

CONCLUSION

FHL tendonitis is more common than the previous evidence suggests and frequently occurs in nonathletes. Once it was diagnosed by detection of tenderness anywhere along the tendon, most frequently at the fibroosseous tunnel, nonoperative treatment focused on specific FHL stretching and immobilization in more severe cases reduced the symptoms to the extent that 44% of patients decided that surgery was unnecessary. The key to its diagnosis is awareness that this injury is possible because most patients treated in this study had been previously seen by orthopaedic providers who had not appreciated the presence of the condition, leading to a delay in diagnosis and treatment of more than a year in many patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Flexor Hallucis Longus Tendon Impingement Syndrome: All-inside Arthroscopic Treatment and Long-term Follow-up

This study aimed to evaluate the surgical technique and long-term clinical outcomes of all-inside arthroscopic treatment for flexor hallucis longus (FHL) tendon impingement syndrome. We retrospectively evaluated 34 FHL tendon impingement syndrome patients with complete follow-up data who were admitted from June 2015 to August 2018 and underwent the all-inside arthroscopy technique. The subjects consisted of 20 (58.82%) males and 14 (41.18%) females, with a mean age of 32.7 ± 10.2 (range 21-52) years. The cases consisted of 19 (55.88%) right and 15 (44.12%) left feet. The mean disease duration was 18.5 ± 9.1 (range 10-43) months. The visual analogue scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS), Karlsson Ankle Functional Score (KAFS), and 36-item Short Form Health Survey questionnaire (SF-36) scores for pain were 3.6 ± 1.2, 84.1 ± 9.6, 86.3 ± 10.7, and 94.7 ± 9.3, respectively. All patients were treated with all-inside posterior arthroscopy for the debridement of the FHL tendon sheath combined with partial muscle belly resection. Post-operative follow-up and observation of the patients' pain and ankle movement were evaluated using VAS, AOFAS, KAFS, and SF-36. All incisions were healed in the first stage, and no complications such as nerve, blood vessel, or tendon injuries occurred. The hospital stays were 3 to 5 days, with a mean of 3.7 ± 1.3 days. All patients were followed up for 12 to 36 months, with a mean follow-up time of 25.4 ± 8.5 months. By the last follow-up, the ankle joint and hallux movement were normal and returned to the pre-pain state for these patients. The VAS score decreased to 0.2 ± 0.1, while the AOFAS, KAFS, and SF-36 scores increased to 97.7 ± 8.5, 97.9 ± 8.2, and 118.2 ± 8.4, respectively. Advantages of all-inside posterior arthroscopic partial muscle belly resection for the treatment of FHL tendon impingement syndrome include small surgical trauma, fast functional recovery, and reliable outcomes. This procedure is therefore worthy of clinical attention and promotion.

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.

Os Trigonum Syndrome

This article offers an overview of os trigonum syndrome, complications, operative techniques, and the authors' preferred protocol. Os trigonum is an ossicle like many other ossicles in the foot and ankle. Individuals who require repetitive plantarflexion of the ankle for activity may develop symptoms of an enlarged os trigonum. Usually, symptoms will be isolated to the posteriolateral aspect of the ankle. Because of the normal anatomic route of the flexor hallucis longus tendon, its range of motion may also elicit pain to the posterolateral ankle. Conservative, as well as surgical including both endoscopic and open excision, has been described.

Endoscopic Tenolysis of Flexor Hallucis Longus Tendon: Surgical Technique

Flexor hallucis longus tendon release for surgical treatment of functional hallux limitus-associated conditions is described. This release is obtained by arthroscopic correction of the tendon's blockage, which is located at the retrotalar pulley. The procedure restores the ability for dorsiflexion of the first toe in ankle dorsiflexion (positive stretch test result). Such movement was not possible before, causing a modified gait pattern and affecting the biomechanics of the foot and leg. This explains why the procedure creates favorable changes concerning foot dynamics by restoration not only of the normal tendon glide but also of the normal mobility of the subtalar joint.

Posterior Ankle Impingement and Flexor Hallucis Longus Pathology

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.

Posterior Ankle Arthroscopy for Osteochondromatosis of the Posterior Ankle Extra-Articular Space with a Longitudinal Tear of Flexor Hallucis Longus

We report a rare case of osteochondromatosis of the posterior ankle extra-articular space with a longitudinal tear of flexor hallucis longus (FHL). A 77-year-old woman was referred to our hospital with an approximately 4-year history of pain and swelling in the right posterior ankle joint without obvious trauma. The pain had worsened in the previous 2 years. On presentation, she had tenderness at the posteromedial and posterolateral ankle. Imaging revealed several ossified loose bodies in the posterior ankle extra-articular space. We removed the loose bodies, performed tenosynovectomy around the FHL, and released the FHL tendon using a posterior arthroscopic technique via standard posterolateral and posteromedial portals. A longitudinal tear and fibrillation were detected in the FHL. The patient was able to return to her daily activities approximately 3 weeks after surgery. At the 1-year follow-up visit, she continued to have minor discomfort and slight swelling on the posteromedial aspect of the right ankle but had no recurrence of the ossified loose bodies. To our knowledge, this is the first report of osteochondromatosis of the posterior ankle extra-articular space with a longitudinal tear of the FHL that was treated by removal of loose bodies, tenosynovectomy around the FHL, and release of the FHL tendon via posterior ankle arthroscopy.

Effect of extensive tenosynovectomy on diffuse flexor hallucis longus tenosynovitis combined with effusion

OBJECTIVE

The objective of this study was to examine the clinical and magnetic resonance imaging (MRI) outcomes of extensive tenosynovectomy on patients with diffuse flexor hallucis longus tenosynovitis combined with effusion (DFHLT-E).

METHODS

Consecutive patients undergoing extensive tenosynovectomy for DFHLT-E in the same foot and ankle center from January 2013 to December 2016 were selected; a total of 14 patients were included in the final analysis. Patients with a minimum 1-year follow-up were evaluated with physical examination, MRI, American Orthopaedic Foot and Ankle Society (AOFAS) clinical midfoot scale, and visual analog scale (VAS) pain scores.

RESULTS

The 14 patients were followed up for an average of 15.0 ± 2.3 months (12-18 months). There were no recurrences in all clinical examinations at the final follow-up. The AOFAS score was improved from 61.57 ± 10.70 before surgery to 90.28 ± 9.41 at the final follow-up. The difference was statistically significant (p = 0.001). The VAS score was improved from 4.00 ± 0.82 before surgery to 0.43 ± 0.53 at the final follow-up (p < 0.001). MRI examination revealed two patients with small residual and limited effusion with no clinical symptoms. Superficial pin infection was observed in one patient, and two patients had transient neurostimulation.

CONCLUSIONS

Extensive tenosynovectomy is an effective alternative for the treatment of DFHLT-E with less complications or recurrence.

Is there any effect of presence and size of os trigonum on flexor hallucis longus tendon lesions?

BACKGROUND

It was hypnotized that presence and larger size of os trigonum (OT) can affect flexor hallucis longus tendon (FHL), so tenosynovitis, degeneration and partial tear can be developed.

METHODS

A total of 98 (Study group: 50, Control: 48) subjects included to study and compered status of FHL lesions. Sagittal length and axial width of OT were measured on MRI to determine effect of OT on FHL lesions and correlated with arthroscopic findings.

RESULTS

FHL tenosynovitis (p: 0,025), degeneration (p: 0,01) and partial tear (p: 0.008) was identified statistically high in study group. Statistical analysis revealed that as length of OT increased, frequency of degeneration (p: 0.03) and partial tear (p: 0.00) of FHL increased.

CONCLUSION

Analyzes were showed that the presence of os trigonum had an important role on the FHL pathologies. Additional finding of study was to demonstrate that possibility of FHL lesion increased as length of OT extended.

LEVELS OF EVIDENCE

Level 3.

Posterior Arthroscopic Treatment of a Massive Effusion in the Flexor Hallucis Longus Tendon Sheath Associated with Stenosing Tenosynovitis and Os Trigonum

We report a rare case of massive accumulation of fluid in the flexor hallucis longus tendon sheath with stenosing tenosynovitis and os trigonum. A 34-year-old woman presented to our hospital with pain and swelling in the posteromedial aspect of the left ankle joint after an ankle sprain approximately 8 months earlier. There was tenderness at the posteromedial aspect of the ankle, and the pain worsened on dorsiflexion of the left great toe. Magnetic resonance imaging revealed massive accumulation of fluid around the flexor hallucis longus tendon. We removed the os trigonum, performed tenosynovectomy around the flexor hallucis longus, and released the flexor hallucis longus tendon via posterior arthroscopy using standard posterolateral and posteromedial portals. At 1 week postoperatively, the patient was asymptomatic and able to resume her daily activities. There has been no recurrence of the massive accumulation of fluid around the flexor hallucis longus tendon as of 1 year after the surgery. To our knowledge, this is a rare case report of extreme massive effusion in the flexor hallucis longus tendon sheath with stenosing tenosynovitis and os trigonum treated successfully by removal of the os trigonum, tenosynovectomy around the flexor hallucis longus, and release of the flexor hallucis longus tendon via posterior ankle arthroscopy.

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.

Treatment of hindfoot and ankle pathologies with posterior arthroscopic techniques

The two-portal hindfoot arthroscopy is an effective procedure enabling direct visualisation of posterior ankle pathology with low invasiveness.

An important stage of the hindfoot endoscopy is localisation of the flexor hallucis longus (FHL) tendon to protect the neurovascular bundle which is located just medial to it.

Posterior ankle impingement syndrome and FHL tenosynovitis are common causes of posterior ankle pain and frequently occur together.

Posteriorly localised talar osteochondral lesions, Achilles tendon disorders, osteoarthritis, talar bone cysts and talar fractures are among the other pathologies that can be treated with hindfoot arthroscopy.

Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160055. Originally published online at www.efortopenreviews.org