Comparative Study of Degree of Great Toe Movement after Complete and Partial Flexor Hallucis Longus Harvest in Free Fibula Flap.

Background The flexor hallucis longus (FHL) muscle is crucial in fine motor control of the great toe but the muscle is often sacrificed in free fibula flap (FFF) reconstruction. The aim of this study was to compare great toe movement between complete and partial FHL resection during FFF harvest to see if FHL can be left behind (without undergoing fibrosis) in situ when bulk is not required at the recipient site. Methods A prospective, cross-sectional, observational study was performed including patients undergoing FFF harvest over a 2-year period. Movement of great toe interphalangeal joint was recorded of operated and unoperated legs in patients undergoing partial and complete FHL harvest and data analyzed. Results There was a statistically significant ( p < 0.05) difference between the two groups of patients. Conclusion FHL can be safely left in situ in patients not requiring bulk at the recipient site as blood supply, nerve supply, and muscle function are not compromised in partial FHL harvest. Further image-based and dye-based studies are warranted.

Effect of simultaneous bilateral surgery or simultaneous arthroscopic ankle lateral ligament repair in hindfoot endoscopic surgery for posterior ankle impingement syndrome in athletes.

BACKGROUND: Posterior ankle impingement syndrome (PAIS) is sometimes complicated by bilateral cases and lateral ankle ligament injuries. Reports on bilateral surgery for PAIS and simultaneous surgery for lateral ankle ligament injury are scarce in the literature. METHODS: We present a 2-year follow-up of 76 athletic patients who underwent endoscopic hindfoot surgery for PAIS. Patients were divided into those who underwent unilateral or simultaneous bilateral surgery and PAIS surgery alone or simultaneous bilateral PAIS surgery without arthroscopic ankle lateral ligament repair. RESULTS: All patients returned to full athletic activities postoperatively. There was no difference in all subscales of the SAFE-Q score between groups except for mean days after surgery for full return to athletic activities. CONCLUSION: Simultaneous bilateral surgery and simultaneous arthroscopic lateral ankle ligament repair had no negative effect on subjective clinical evaluation 2 years after surgery in hindfoot endoscopic surgery for PAIS. LEVEL OF EVIDENCE: III, retrospective case-control study.

Positional and dimensional relation of tendons around the first metatarsal bone with hallux valgus.

PURPOSE: It was aimed to reveal whether the positions and dimensions of the extrinsic and intrinsic muscle tendons related to the hallux around the first metatarsal bone are affected by the severity of hallux valgus (HV) and whether tendon positional changes and tendon sizes affect each other. METHODS: In formalin-fixed 46 feet, three HV angle subgroups (normal, mild, and moderate/severe) were defined. Width, thickness, and cross-sectional area (CSA) of tendons of the extensor hallucis longus (EHL) and brevis (EHB), abductor hallucis (AH), and flexor hallucis longus (FHL) were measured. On the clock model created in coronal plane, positional variations of each tendon were determined. RESULTS: In the moderate/severe HV group, thickness and CSA of the EHB, width and CSA of the AH were smaller, compared to mild HV. Width and CSA of the FHL were smaller in moderate/severe HV than in the normal. Regardless of HV, the width and CSA of the FHL were greater in cases where the FHL was located more lateral, and the width of both FHL and AT were greater in cases where AH located was more plantar. CONCLUSION: The smaller tendon size of two intrinsic (one plantar and one dorsal) and one extrinsic muscle in the moderate/severe HV group indicates that changes in the tendons are evident in cases of high severity of HV but not in cases of mild HV. Accordingly, the changes do not appear to be due to a factor limited to only one aspect of the foot. It is recommended to consider the possible biomechanical effects of AH, FHL, and EHB tendon dimensional weakness in surgical planning in moderate/severe HV cases.

Claw Toe: Anatomic Guide for Injection of Botulinum Toxin into Foot Muscles.

BACKGROUND: Poor response to injection of botulinum toxin (BoNT) into the flexor digitorum longus (FDL) muscle has been reported especially in patients with claw foot deformity. We previously advocated BoNT injection into the flexor hallucis longus (FHL) muscle in such patients. Here, we determined the functional and anatomical relationships between FHL and FDL. METHODS: Toe flexion pattern was observed during electrical stimulation of FHL and FDL muscles in 31 post-stroke patients with claw-foot deformity treated with BoNT. The FHL and FDL tendon arrangement was also studied in five limbs of three cadavers. RESULTS: Electrical stimulation of the FHL muscle elicited big toe flexion in all 28 cases examined and second toe in 25, but the response was limited to the big toe in 3. FDL muscle stimulation in 29 patients elicited weak big toe flexion in 1 and flexion of four toes (2nd to 5th) in 16 patients. Cadaver studies showed division of the FHL tendon with branches fusing with the FDL tendon in all five limbs examined; none of the tendons was inserted only in the first toe. No branches of the FDL tendon merged with the FHL tendon. CONCLUSION: Our results showed coupling of FHL and FDL tendons in most subjects. Movements of the second and third toes are controlled by both the FDL and FHL muscles. The findings highlight the need for BoNT injection in both the FDL and FHL muscles for the treatment of claw-toe deformity.

Arnold Kirkpatrick Henry (1886-1962) and his eponym (Master Knot of Henry): a narrative review.

PURPOSE: The aims of this review were to form a more precise description for Master Knot of Henry (MKH), and to modify classifications related to interconnections between flexor hallucis longus (FHL) and flexor digitorum longus (FDL) for showing all configurations in the literature. METHODS: A literature search was performed in main databases to obtain information related to anatomical definitions and variations of MKH. The search was carried out using the following keywords: "Master Knot of Henry", "Chiasma plantare", "Flexor hallucis longus" and "Flexor digitorum longus". Information extracted from the studies was: sample size, numerical values, classifications, variation types, incidence of types, anatomical definitions of MKH, year of publication, and type of study. RESULTS: This study proposes that MKH should be defined as the intersection territory where FDL crosses over FHL in the plantar foot. The postchiasmatic plantar area located at distal to MKH (the narrow space between MKH and the division of FDL) should be termed as the triangle of Henry. Moreover, the classification systems showing different configurations related to interconnections situated at Henry's triangle were updated as eight types to present all forms in the literature. CONCLUSION: Our definitions may assist in determining the precise anatomical boundaries of MKH, and thus facilitate the use of MKH as a surgical landmark. In addition, our modified classification systems covering all variations in the current literature may be helpful for surgeons and anatomists to understand formations of the triangle of Henry, and the long flexor tendons of the lesser toes.

Return to Sports Activities After Flexor Hallucis Longus Transfer for Neglected Achilles Tendon Rupture.

Transfer of the flexor hallucis longus (FHL) is known to be effective in the treatment of neglected Achilles tendon rupture (ATR). However, evidence on the return to sports activity levels and clinical outcomes is not sufficient. The aim of this study was assessing clinical outcomes and level of sports activity after FHL tendon transfer for treatment of neglected ATR. Twenty-eight patients who underwent FHL transfer for neglected ATR were analyzed retrospectively. Sports activity status was assessed using the Tegner Activity Scale (TAS). Clinical outcomes were evaluated using the Achilles tendon total rupture score and the American Orthopedic Foot and Ankle Society Ankle-Hindfoot Scale. By the post hoc power analyses, the power level of more than 80% was identified. The preinjury median TAS score was 4 point and unchanged at the last follow-up. The mean Achilles tendon Total Rupture Scores and American Orthopedic Foot and Ankle Society Ankle-Hindfoot Scale scores at the last follow-up were 81 and 93, respectively. While the median TAS was unchanged, 9/28 patients suffered from lower activity level after the procedure. In conclusion, midterm results of FHL transfer for neglected ATR were shown to be favorable. The median TAS score was maintained. Nonetheless, 32% of patients returned to sports activities with a TAS score 1 point lower than that at preinjury and with less favorable clinical outcomes.

Chronic Rupture of Achilles Tendon Caused by Haglund's Deformity: A Case Report.

A chronic Achilles tendon rupture is a tendon rupture occurring more than 4-6 weeks after a traumatic injury. Haglund's deformity, caused by bony abnormalities in the ankle (mostly due to osteophyte or bone spur), can cause chronic inflammation and degeneration of the Achilles tendon, eventually leading to rupture. This presents a challenge for clinicians who provide tendon repair procedures. We present a 69-year-old woman who had difficulty moving her left leg and had a deformity on the left leg compared to her right leg after falling nine months before but with pain starting three months before the accident. There was a seven-centimeter gap in the calcaneus with a positive Thompson test. The Haglund's deformity on the left calcaneus was visible on the ankle X-ray. The patient had a chronic total rupture of the left Achilles tendon, which was treated with a flexor hallucis longus (FHL) tendon transfer and resection of the deformity. One week after surgery, the patient's ability to walk and the shape of the left leg improved. This case report describes a chronic left Achilles tendon condition that was successfully repaired through tendon repair surgery using FHL tendon transfer and removal of Haglund's deformity.

Retro-Malleolar Z-Plasty of Flexor Hallucis Longus Tendon in Post-Traumatic Checkrein Deformity: A Case Series and Literature Review.

Checkrein deformity (CD) is a dynamic deformity of the hallux characterized by flexion contracture of the interphalangeal (IF) joint and extension contracture of the metatarsophalangeal (MTP) joint, worsened by ankle dorsiflexion. It is due to post-traumatic or ischemic retraction of the long hallux flexor tendon (FHL) following soft tissue trauma, leg fractures, ankle fractures and, more rarely, calcaneal or talar fractures. Diagnosis is essentially clinical, associated with imaging, to rule out unrecognized causes and evaluate fracture healing process. Few cases are reported in literature without univocal treatment. Background and Objectives: To analyze clinical and functional outcomes in patients with CD treated with release and retro-malleolar Z-plasty lengthening of FHL tendon. Materials and Methods: Patients diagnosed with CD treated with retro-malleolar (at tarsal tunnel) Z-plasty lengthening of the FHL tendon between January 2016 and August 2020 were included. Clinical and functional outcomes were collected on admission and post-surgery and analysed retrospectively. Patients with a minimum follow-up of 18 months were included. Results: A total of 14 patients, with mean age of 37.4 years old, with CD diagnosis were included in the study. All patients were suffering from post-traumatic CD and the mean time from trauma to onset of deformity was of 7 months (range 1−12). At a mean follow-up of 31.8 months (range 18−48) we found a significant improvement (p < 0.05) in terms of pain relief (VAS), function (AOFAS score) and ROM of the IP and MTP hallux joints. No recurrence, loss of strength, nerve injury or tarsal tunnel syndrome were observed. No patient required revision surgery. Conclusions: In this case series the retro-malleolar FHL tendon Z-plasty proved to be a suitable option for CD correction, allowing a good clinical and functional recovery.

Secondary reconstruction of chronic Achilles tendon rupture: flexor hallucis longus transfer versus plantaris longus augmentation.

INTRODUCTION: Chronic Achilles tendon rupture is primarily caused by degenerative processes of multifactorial origin. In addition to secondary repair (SR) with augmentation of the plantaris longus tendon, the transfer of the flexor hallucis longus tendon (FHL) to the calcaneus is a recognised reconstruction procedure. This paper aims to provide a direct comparison based on clinical scores and objectifiable strength measurements. METHODS: We analysed data for 60 patients (46 males and 14 females) with chronic Achilles tendon rupture, including 34 (mean age 57 years) treated with FHL and 26 (mean age 52 years) with SR between 2016 and 2020 (mean follow-up of 49 months). The follow-up included the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scoring System (AOFAS-AH) and Visual Analogue Scale Foot and Ankle (VAS FA), the 12-item Short Form Survey (SF-12) and the objectifiable strength measurement using the dynamometer BIODEX®. Pre-existing gait disorders and permanent pain therapy led to exclusion. RESULTS: The mean AOFAS-AH was 87.8 points (FHL: 85.6, SR: 90.6), the mean VAS FA was 78.1 points (FHL: 73.7, SR: 83.6), the mean PCS was 48.2 points (FHL: 46.3, SR: 50.7) and the mean MCS was 54.1 points (FHL: 55.0, SR: 53.0). The maximum torque for plantar flexion was 56.7 Nm on average (FHL: 51.0, SR: 63.7). A total of seven (11.7%) wound infections requiring revision occurred (FHL: 4 (11.8%), SR: 3 (11.5%)). All measurements did not differ significantly between the groups (p > 0.05). CONCLUSION: The results of the study prove the equivalence of FHL and SR based on the clinical scores as well as on the strength measurement using BIODEX®. Nevertheless, a higher withdrawal because of morbidity with a tendency for prolonged incapacity to work in the FHL group has to be taken into account. The present work provides the basis for a prospective comparison in future studies.

Ultrasonographic test for detecting the chiasma plantare formation between the flexor hallucis longus and flexor digitorum longus.

PURPOSE: Flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons are frequently used in surgery. Therefore, it is necessary to evaluate the chiasma plantare formation preoperatively. The development of ultrasonography (US) may help the chiasma plantare formation evaluation. The purpose of this study is to prove the usefulness of the US method using cadavers. METHODS: Eleven cases (twenty-two ankles) were obtained from Asian adult cadavers. At first, we evaluated and compared the chiasma plantare formation using US. Later, we evaluated that using the findings after dissection as type A (connection from FHL to FDL of the second toe), type B (connection from FHL to the second and third toes), type C (connection from FHL to the second through fourth toes), or type D (connection from FHL to all lesser toes). RESULTS: Chiasma plantare formation was classified as types A and B in fifteen and seven ankles, respectively. After dissection, chiasma plantare formation was classified as types A, B, and C in fourteen, six, and two ankles, respectively. Therefore, there was an 86% similarity between the two methods. CONCLUSIONS: Chiasma plantare formation can be reliably and noninvasively evaluated using US. This may be useful for preoperative rehabilitation or surgical procedure planning.

Pigmented Villonodular Synovitis of the Flexor Hallucis Longus Tendon Treated by Means of Tendoscopy and Endoscopic Synovectomy.

Pigmented villonodular synovitis (PVNS) of the tendon sheath (tenosynovial giant cell tumor) is a rare disorder that is often misdiagnosed because of slow growth and an atypical presentation. Open surgical excision is the treatment of choice, although recurrence is a common complication. In this report, a case of PVNS of the flexor hallucis longus tendon in the ankle and hindfoot is described. The diagnosis was confirmed by endoscopic inspection and biopsy, and complete synovectomy was performed through the endoscope. The patient remained disease free after 24 months of follow up.

A histological study on the tendons at chiasma plantare in pes cavus.

INTRODUCTION: In the dysfunction of large muscles of the leg, tendon transfer surgery is found to be very helpful in restoring the normal function of these muscles. The tendons involved in the chiasma plantare play a major role in this regard. OBJECTIVE: The present cadaveric study has been carried out in cadavers presenting pes cavus. MATERIAL AND METHODS: Cadaveric feet presenting pes cavus were identified based on their foot prints. All these tendons and their interconnections were subjected to histological procedures. The sections of the tendons were stained with hematoxylin and eosin in order to identify the underlying pathologies in the tendons. RESULTS: Various types of tendinous interconnections between the tendons of flexor digitorum longus and flexor hallucis longus were noted. The histological findings showed infiltration of lymphocytes in the tendon sheath indicating tenosynovitis and tendinitis. This could be attributed to the compression of the tendons. A few tendons were also stretched due to the skeletal framework of the foot in pes cavus. The bones along the medial longitudinal arch in pes cavus feet could tend to develop spurs or elongated tuberosity that could impinge on the tendons causing the tendons to stretch and elongate. CONCLUSION: In harvesting the tendons for grafting, the surgeons must be aware about the pathologies involved, such as tendinitis or tenosynovitis, in order to reduce the time taken for the healing of the graft post-surgery. These variations and histological findings can sub-serve as an efficient guide for the restoration of non-functioning muscles of the lower limb.

Dynamic medial column stabilization using flexor hallucis longus tendon transfer in the surgical reconstruction of flatfoot deformity in adults.

BACKGROUND: A common challenge in flatfoot reconstruction arises when there are multiple locations of collapse within the medial column. An extension of arthrodesis may lead to complications such as stiffness or adjacent joint arthritis. The purpose of this study was to report outcomes of flatfoot reconstruction using the dynamic medial column stabilization (DMCS) technique, which transfers the flexor hallucis longus (FHL) tendon to the first metatarsal base to support the entire medial column. METHODS: We retrospectively reviewed 14 consecutive patients (14 feet) who underwent DMCS as an adjunct to flatfoot reconstruction. In all cases, a medial displacement calcaneal osteotomy and gastrocnemius recession were performed to address hindfoot valgus deformity and heel cord tightness, respectively. Deformity correction was assessed using preoperative and postoperative weightbearing radiographs. The newly defined metatarsal-cuneiform articular angle (MCAA) and naviculo-cuneiform articular angle (NCAA) were measured to assess correction at each medial column joints. Clinical outcomes included the FFI and VAS scores. Any complications related to the surgery were investigated. RESULTS: All radiographic parameters significantly improved postoperatively. The sagittal plane correction occurred at all three joints within the medial column. Clinically, both FFI and VAS improved significantly at the final follow-up. One patient developed plantar pain under the first metatarsal head that may have been associated with the overtightening of the transferred tendon. CONCLUSION: DMCS using FHL tendon transfer to the first metatarsal base was a useful technique for restoring the medial arch and correcting three planar deformities in the setting of flatfoot deformity.

Increased flexor hallucis longus tension decreases ankle dorsiflexion.

BACKGROUND: Restricted excursion of the flexor hallucis longus (FHL) is associated with several clinical problems. An FHL excursion measurement device (EMD) was used to objectively assess differences between patients with clinically normal or tight FHL tendons. METHODS: 188 patients (356 feet) were enrolled. The EMD measured maximum ankle dorsiflexion with the great toe in 15°, 30°, and 45° of dorsiflexion. All had clinical assessment of FHL tightness by their provider independently of the EMD measurement. RESULTS: Increased hallux DF always caused decreased ankle DF. Patients with clinically tight FHLs demonstrated decreased ankle DF compared to normal subjects at all hallux positions (p<0.01). The EMD measurement was not sensitive enough for detection of FHL tightness in individuals. A clinically tight FHL was seen in almost 50% of feet. CONCLUSIONS: Tension in the FHL can limit ankle DF. Clinical tightness of the FHL is likely more common than currently recognized.

Flexor hallucis longus hypertrophy secondary to Achilles tendon tendinopathy: an MRI-based case-control study.

PURPOSE: The purpose of this study was to outline an indirect sign of advanced Achilles tendinopathy on magnetic resonance imaging (MRI), based on the hypothesis that these patients would present with secondary hypertrophy of the flexor hallucis longus muscle (FHL). METHODS: MRI scans of Achilles tendon were analyzed retrospectively in two cohorts. The study group consisted of consecutive patients presenting with clinical signs of Achilles tendinopathy and no previous surgeries, while the control group were patients that had an MRI due to other reasons and no signs of tendinopathy. Two parameters from two muscle bellies were measured and compared on axial MRI scans 4-5 cm above the ankle joint line at the level of greatest thickness: area and diameter of the triceps surae (TS) and of the FHL muscle. Ratios (FHL/TS) were calculated for area (Ar) and diameter (Dm) measurements. Interobserver agreement was analyzed. A receiver operating characteristic (ROC) curve was created for both ratios to assess potential cutoff points to differentiate between the groups. RESULTS: A total of 60 patients for each study group were included. Both ratios Ar(FHL/TS) and Dm(FHL/TS) showed significant higher values in the tendinopathy group (p < 0.001). There were strong to very strong intraclass correlation coefficients (ICC = 0.75-0.93). A diameter ratio Dm (FHL/TS) of 2.0 or higher had a sensitivity of 49% and specificity of 90% for concomitant Achilles tendinopathy. CONCLUSION: In our patient cohort, FHL hypertrophy was observed in patients with Achilles tendinopathy as a possible compensatory mechanism. Measuring a diameter ratio Dm(FHL/TS) of 2.0 or higher on an axial MRI, may be indicative as an indirect sign of functional deterioration of the Achilles tendon.

Comparative Effects of One-Shot Electrical Stimulation on Performance of the Flexor Hallucis Longus Muscle in Professional Dancers: Percutaneous Versus Transcutaneous?

OBJECTIVE: High demand of flexor hallucis longus (FHL) in the positions of extreme flexion of the ankle and toes is required in the dance. The aim was to investigate the effects of single-shot of ultrasound-guided percutaneous neuromodulation (PNM) vs. single-shot of transcutaneous electrical nerve stimulation (TENS) in performance of the FHL muscle in professional dancers. MATERIALS AND METHODS: Thirty-two female healthy dancers were divided into two groups: TENS group and PNM group. The stimulation interventions consisted in the application of a square wave biphasic electrical current for a total of 1.5 mins. Range of motion (ROM) of first metatarsophalangeal joint, balance test, and unilateral heel raise fatigue test were performed in dominance limb. RESULTS: There were no differences between both groups in the baseline measurements. Compared to their baseline values, the TENS group statistically improved balance (p < 0.01, d = 0.6), ROM (p < 0.001, d = 0.3), and endurance (p = 0.04, d = 0.5). The PNM group only statistically improved balance and endurance (p < 0.001), with a large effect size for both test (d = 0.8 and d = 2.24, respectively). After interventions, there were no significant differences between TENS and PNM groups for all variables. However, PNM was qualitatively more effective because the percentage change in mean was greater and effect size was large for the balance test and endurance test. CONCLUSIONS: Simple single-shot procedure with percutaneous or TENS provided immediate performance improvement of FHL muscle in dancers, being PNM the more effective intervention.

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.

Checkrein Deformity of the Hallux Caused by Misplaced Suture-Button Syndesmosis Fixation: A Case Report.

Ankle fractures are common injuries. If an ankle fracture is combined with tibiofibular syndesmosis separation, then tibiofibular transfixation should be used to stabilize the syndesmosis; in such cases, flexible (suture-button) fixation is an option. We surgically treated a male patient's unstable ankle fracture with internal fixation devices, including a suture-button fixator, and observed the development of a flexor hallucis longus checkrein deformity in the postoperative period. The aim of this report is to describe this rare postoperative complication associated with the use of suture-button transfixation of the tibiofibular syndesmosis.

Neglected Iatrogenic Flexor Hallucis Longus Tendon Rupture After Haglund's Endoscopic Surgery: A Case Report.

Rupture of the flexor hallucis longus (FHL) tendon is a rare condition that can occur with direct or indirect trauma; most of the injuries are complete ruptures resulting from laceration. Endoscopic calcaneoplasty is used for treatment of symptomatic Haglund's deformity, and complications of this procedure are rare. Iatrogenic FHL tendon rupture occurring after endoscopic calcaneoplasty has not been reported previously. This case report presents a rare complication after endoscopic calcaneoplasty and the proper method of treatment.

Does Function Determine the Structure? Changes in Flexor Hallucis Longus Muscle and the Associated Performance Related to Dance Modality: A Cross-Sectional Study.

Background and Objectives: Flexor hallucis longus pathology is one of the most common conditions of the ankle and foot in dancers, due to the high demand of dance movements performed in an extreme plantar flexion and dorsiflexion range of motion. The objectives of this study were to determine the bilateral differences between the thickness and cross-sectional area of the flexor hallucis longus muscle in dancers, to establish possible differences between dance modalities, and to analyze whether there is a correlation between ultrasonographic parameters or performance variables and the dance modality. Material and Methods: A sample of 50 (29 classical and 21 contemporary) full-time pre-professional female dancers were included in the study. The thickness and cross-sectional area of the flexor hallucis longus muscle were evaluated for both limbs using ultrasound imaging. The range of movement of the first metatarsophalangeal joint was measured using functional extension with maximal ankle plantarflexion, balance was measured in a unilateral stance with the heel raised, endurance was evaluated through a modified heel rise fatigue test, and a counter movement jump to assess the vertical jump performance was measured bilaterally. Results: There were no significant differences recorded between the dominant and non-dominant limbs for each variable, within both groups. Contemporary dancers showed a greater thickness and cross-sectional area of the flexor hallucis longus muscle than classical dancers. However, classical dancers showed an increase of balance, endurance, range of movement of the first metatarsophalangeal joint, and counter movement jump with respect to contemporary dancers. Conclusion: Bilateral symmetry was identified in all variables for both groups. The size and performance of the flexor hallucis longus muscle may be influenced by the specific nature of dance modality.