Endoscopic flexor hallucis longus transfer in the patients with chronic achilles rupture.

Research Type: Level 5 - Case report, Expert opinion, Personal observation Introduction/Purpose: Chronic Achilles tendon ruptures are challenging to manage, often requiring surgical intervention to restore function and alleviate pain. The flexor hallucis longus (FHL) tendon transfer has emerged as a viable solution for augmenting repair in neglected cases of Achilles tendon rupture. This procedure can be performed either as an isolated transfer or as an augmentation to a primary tendon repair. However, the outcomes of these two approaches remain uncertain, with variations in patient outcomes. This study aims to compare the clinical outcomes, return to activity, and re-rupture rates between isolated FHL tendon transfer and FHL augmentation for the management of chronic Achilles tendon ruptures. Methods: A systematic review was conducted in January 2025, utilizing multiple databases, including PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library, to identify clinical studies that assessed the outcomes of isolated versus augmented FHL tendon transfer for chronic Achilles tendon ruptures. Studies were selected based on their inclusion of clinical outcomes, patient demographics, return to activities, and complication rates. Data were extracted and analyzed to provide a comparative evaluation of the two techniques, focusing on key outcome measures such as the Visual Analog Scale (VAS) for pain, American Orthopaedic Foot and Ankle Society (AOFAS) scores, Achilles Tendon Rupture Score (ATRS), and re-rupture rates. Results: We included 40 studies, involving 819 patients (522 in the augmented cohort, 305 in the isolated cohort). The mean age was 50.9 years (augmented) and 53.3 years (isolated), with mean follow-up of 33.8 and 20.19 months, respectively. The mean time between injury and surgery was 141.6 days (augmented) and 131.9 days (isolated). Postoperative outcomes showed a significant improvement in both cohorts, with the augmented group achieving a mean VAS score of 1.06 (preop: 4.8), AOFAS score of 91.9 (preop: 60.6), and ATRS of 88.13. In the isolated group, VAS improved to 0.3 (preop: 4.26), AOFAS to 91.6 (preop: 51.09), and ATRS to 81.36. The mean return to activities was 24.3 weeks (augmented) and 21.3 weeks (isolated). Re-rupture rates were below 1% in both cohorts. Conclusion: Both procedures yielded favorable clinical outcomes, with significant improvements in pain, function, and activity levels. The augmented group showed a slightly higher ATRS and lower complication rates, although the differences between groups were minimal. Both techniques had low re-rupture rates, indicating their reliability in treating chronic Achilles ruptures. While both approaches provide effective treatment, the isolated FHL transfer may offer a less invasive option with comparable outcomes to the augmented technique and a slightly faster return to activities. Future studies with higher-quality evidence and longer follow-up are needed to definitively determine the optimal approach for chronic Achilles tendon rupture repair.

Background: Chronic Achilles tendon ruptures (CATRs) pose a clinical challenge because guidelines on optimal treatment modalities are lacking. This meta-analysis aims to investigate the use of Flexor Hallucis Longus (FHL) tendon transfer as a treatment option. Methods: A literature search was performed across multiple databases from inception until 31 July 2025. The databases searched included Ovid MEDLINE®, EMBASE (Elsevier), Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews. Included studies presented CATR patients of all ages, with no previous surgeries to the ankle, who were managed with an FHL tendon transfer (PROSPERO ID: CRD42023489724). Results: Sixteen studies met the eligibility criteria with 323 patients. For functionality, baseline AOFAS-AH (American Orthopaedic Foot & Ankle Society—Ankle Hindfoot) scores were 56.85 (95% CI: 51.03–62.68, I2 = 96%). At ≥12 months post-operative follow-up, AOFAS-AH scores were 91.46 (95% CI: 88.45, 94.48, I2 = 93%). ATRS (Achilles Tendon Rupture Score) at baseline was reported as 31.04 (95% CI: 5.80, 56.28, I2 = 99%). At ≥12 months post-operative follow-up, ATRS amounted to 90.73 (95% CI: 83.69, 97.77, I2 = 89%). Overall complication rates were 7.5% (CI: 0.04,0.11, I2 = 40%), consisting of superficial infections at 4.2% (95% CI: 0.01, 0.07, I2 = 0%), activity limitations at 4% (95% CI: 0.01, 0.08, I2 = 0%) and disturbed wound healing at 3.8% (95% CI: 0.01, 0.06, I2 = 0%). The minimum clinically important difference (MCID) for ATRS was achieved at 12 months onwards. Conclusions: Surgical management of CATR patients with FHL tendon transfer appears to improve functionality and subjective outcomes, supporting its use amongst the treatment modalities available.

Introduction: Several factors, including diabetes and smoking, increase the risk of and predisposition for complications of foot and ankle surgeries; however, studies assessing the effects of obesity remain scarce. The objective of this study is to assess the effects of obesity on functional outcomes of flexor hallucis longus (FLH) tendon transfer surgery in patients with chronic Achilles tendinopathy. Methods: A retrospective study was performed with patients aged 18 years or older who underwent FHL tendon transfer between March 2010 and May 2015. The characteristics recorded were sex, age, body mass index (BMI), American Orthopedic Foot and Ankle Society (AOFAS) score, Foot and Ankle Outcome Score (FAOS) and ankle plantar flexion and dorsiflexion strength, assessed using an isokinetic dynamometer. Results: The sample had 24 participants (13 women and 11 men) with a mean age of 55.7 years; among them, 13 were obese (BMI>=30), and 11 were nonobese (BMI<30). After a mean follow-up time of 66 months, the FAOS of the sample increased from 28 to 91 points (p=0.000). No significant difference in the postoperative AOFAS score or FAOS was found between the subgroups (p>0.05), with values of 83 and 86.7 points (AOFAS) and 92.72 and 90 points (FAOS) for obese and nonobese patients, respectively. The comparison of the strength of each motion revealed no significant difference (p>0.05) between subgroups. There was no association between BMI and postoperative functional outcomes (AOFAS score and FAOS) (p>0.05) or correlation between BMI and the strength of the operated ankles. Conclusion: Our findings indicate that flexor hallucis longus tendon transfer surgery in Achilles tendinopathy is effective for obese and nonobese patients based on the AOFAS and FAOS scores and dynamometry results.

Objective To investigate the operative technique and clinical effects of V-Y advancement and flexor hallucis longus tendon transfer in the treatment of chronic achilles tendon ruptures. Methods Twenty-six patients with chronic achilles tendon ruptures treated between February 2012 and February 2013 were involved in the study, including 20 males and 6 females, at age of 22 to 58 years(average 33.6 years). The length of achilles tendon defect after intra-operative debridement is ranging from 3 to 5 cm. Limited open repair of chronic achilles tendon ruptures using V-Y advancement and flexor hallucis longus tendon transfer were performed and the healing time and complications were recorded. The pre- and postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scores, visual analog scale scores for pain and Leppilahti achilles tendon repair score were compared. Results Twenty-one patients were followed up for 12 to 26 months (average 16.4 months) and five cases were lost.All incisions were in primary healing, without any complications such as infection, nerve injury and secondary rupture. The average healing time of achilles tendons was 12 weeks according to MRI imaging and the average ossification time of interference screws was 18 months. At latest follow up, the American Orthopaedic Foot and Ankle Society ankle-hindfoot scores improved from (52.6±15.4) preoperatively to (96.8±2.5). Similarly, preoperative Visual analog scale score was (5.71±1.56), and mean postoperative Visual analog scale was (1.24±0.44). Besides, Leppilahti achilles tendon repair score was improved from (68.56±7.43) to (92.58±5.1). There were significant differences between the pre- and postoperative scores in all the three evaluations (P<0.05). Conclusions Limited open repair of chronic achilles tendon ruptures using V-Y advancement and flexor hallucis longus tendon transfer may be a good option for a defect gap ranging 3 to 5 cm. It is a safe and effective surgery due to its simpleness and less complications. Key words: Chronic achilles tendon injury; V-Y advancement; Tendon transfer; Fracture healing; Treatment outcome; Postoperative complications

Endoscopic flexor hallucis longus (FHL) tendon transfer can be used in the management of acute or chronic Achilles tendon rupture (ATR), including in elite sportspeople. A recent cadaveric study demonstrated that an increased ultimate load could be applied using an FHL tendon transfer with interference screw and cortical button applied using a tension slide technique compared with interference screw alone. The aim of this study was to explore patient-reported functional outcomes following this modification to this operation. We reviewed the imaging, history, patient-related outcome measures (PROMs), and complications of 17 patients who underwent endoscopic FHL tendon transfer for chronic ATR using the modified FHL reconstruction technique. The primary outcome was the Manchester-Oxford Foot Questionnaire (MOxFQ), EuroQol-5 Dimensions (EQ-5D), and visual analog score for pain (VAS-Pain) with a mean follow up of 1.5 years. Seventeen patients (11 male, 6 female) underwent endoscopic FHL tendon transfer for chronic ATR between September 2020 and May 2023. Mean (SD) age at the time of surgery was 58.3 (16.1) years, and mean (SD) BMI was 27.6 (4.8). A specific event in the history associated with the rupture was present in 13 of 17 patients (76.5%); the median (IQR) time between injury and surgery was 33 weeks (21-42). Sixteen surgeries were primary procedures for chronic ATR, and 1 surgery was a revision procedure after a failed open acute ATR repair. MOxFQ, EQ-5D, and VAS-pain scores all showed a statistically significant improvement postoperatively (minimum 10 months) when compared to preoperative scores. There was 1 symptomatic complication of tibial neuritis (5.9%). Endoscopic FHL tendon transfer for chronic ATR augmented using a cortical button as well as an interference screw seems to be a safe and effective procedure, with patients reporting a statistically significant improvement in health-related quality of life, pain, and specific foot and ankle outcome function.Level of Evidence: Level IV, case series.

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.

Background: Flexor hallucis longus (FHL) tendon transfer aims to relieve pain and restore function after Achilles tendon rupture in patients with Achilles tendinopathy. The choice of operative treatment for chronic Achilles tendon disease is based on the size of the tendon rupture. Our aim was to convey our experience in treating Achilles tendon rupture using FHL tendon transfer. Methods: This study included 22 patients (22 ankles) with Achilles tendon rupture after a history of Achilles tendinopathy in the form of ankle pain and edema for a mean period of 1 yr before trauma. Patients were followed for a mean period of 2 yr. The American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score was used for outcome measurement. Results: Twenty-two patients (22 ankles) had FHL tendon transfer (mean age 50.3 yr, follow-up period 2 yr). The AOFAS score improved from 68.9 to 88 (P&lt;0.001), revealing significant improvement in ankle pain, function, and stability. Conclusions: This study supports the concept that FHL tendon transfer for Achilles tendon rupture in patients with Achilles tendinopathy is the procedure of choice and provides excellent clinical and functional results. Level of Evidence: Level IV, prospective cohort study.

Infection after Achilles tendon (AT) repair can lead to defects in both the tendon and the surrounding soft tissue. In such cases, a two-stage surgical approach is generally adopted, with soft tissue reconstruction performed initially, followed by secondary tendon reconstruction. A reverse sural artery flap (RSAF) after AT repair is not commonly performed due to potential damage to the flap pedicle. This study aims to evaluate the clinical outcomes of simultaneous flexor hallucis longus tendon (FHLT) transfer and RSAF to treat soft tissue and tendon defects resulting from infection after AT repair.We reviewed 20 patients who had undergone one-stage reconstruction of AT and soft tissue defects resulting from infection after AT repair using FHLT transfer and RSAF between October 2012 and October 2022, with a minimum of a 1-year postsurgical follow-up. Surgical outcomes were assessed based on the success of the flap, recurrence of infection, and tendon re-rupture. Clinical evaluation included visual analog scale (VAS) score, ankle range of motion, and patient-reported components of the American Orthopaedic Foot and Ankle Society (AOFAS) score (maximum of 68 points).All flaps were successful. The mean size of the flap was 7.2×4.1 cm2. There was no recurrence of infection or tendon re-rupture. The mean VAS and AOFAS scores were 0.5 and 64.6, respectively. The mean ankle joint range of motion was 13.5° for dorsiflexion and 35° for plantar flexion.One-stage reconstruction with FHLT transfer and RSAF is a safe and effective surgical method in patients with tendon and soft tissue defects after AT repair.

Objective To evaluate the clinical results of flexor hallucis longus （FHL） tendon transfer in treatment of patients with Achilles tendon defects of more than 6 cm. Methods Between January 2005 to February 2009, 19 patients with Achilles tendon defects, 13 males and 6 females, were treated with FHL tendon transfer. Their ages ranged from 20 to 61 years, with an average of （42. 6 ± 8.2）years. Fifteen defects were found during tendonitis debridement, and 4 were old ruptures. Time from rupture to surgery ranged from 0 to 6 months （average, 2.6 months）. Defects were 6 cm to 10 cm long. Procedures were performed in a two-incision manner. The postoperative ROM of ankle joint, American Orthopaedic Foot and Ankle Society（AOFAS） and visual analogue scale（VAS） scores were recorded at 3 months, 12 months,and the last follow-up. The results were statistically analyzed to evaluate the functional recovery. Results Follow-ups lasted from 12 to 48 months （average, 22. 2 months）. At the last follow-up, the average ROM of ankle joint was 17.8°± 1.9° at dorsal flexion and 39.1°±2.3° at plantar flexion, and the last average AOFAS score was up to （91.8 ± 1.7）, significantly different from those at 3 months after surgery （P〈0.05）, but not significantly different from those at 12 months （P〉0.05）. The difference were significant between the results of 3 months and 12 months （P〈0.05）. The last average VAS score was （1.0±0.7）,significantly different from those at 3 months and 12 months（P〈0.05） . There was also significant differences between the VAS scores of 3 months and 12 months （P〈0.05）. Patient＇s satisfaction was 100%.Conclusion FHL tendon transfer is an efficient procedure for long Achilles tendon ruptures associated with tendonitis in relieving pain and maintaining the function of ankle joint. Key words: Achilles tendon; Tendon injuries; Flexor hallucis longus tendon

There are multiple surgical options for treatment of chronic Achilles tendon (AT) rupture according to the classifications and length of defect. However, no gold standard method has been confirmed, and there is no clear evidence to support the superiority of 1 procedure over others. This study aimed to evaluate the long-term clinical outcome of flexor hallucis longus tendon (FHL) transfer for chronic AT rupture with large defect. Clinical data of patients treated with FHL transfer due to chronic AT rupture between January 2009 and October 2019 were reviewed retrospectively. All cases were presented with AT rupture for more than 4 weeks after injury. The gap between ruptured ends was > 5 cm after debridement in all patients. The harvest of FHL was performed through a single incision in accordance with AT rupture debridement in all cases. Clinical outcomes were assessed with AOFAS ankle-hindfoot scale, Achilles tendon total rupture score and AOFAS hallux metatarsophalangeal-interphalangeal scale. Twenty-eight patients were followed successfully for 62.6 ± 22.2 months. According to the complete datasets obtained from 28 patients, none of the tendons re-ruptured. The AOFAS ankle-hindfoot scale and Achilles tendon total rupture score at last follow-up visit was 90.4 ± 5.7 and 89.8 ± 5.3 respectively, which revealed statistically significant improvement from the preoperative score of 61.1 ± 6.7 and 53.8 ± 8.3. The AOFAS hallux metatarsophalangeal-interphalangeal scale at last follow-up visit was 87.5 ± 6.1. The FHL transfer through a single incision for chronic AT rupture with large defect is a safe and simple method with low risk of morbidity and complications.

To investigate of effectiveness of free fascia lata flap assisted by indocyanine green angiography (ICGA) in treatment of Myerson type Ⅱ and Ⅲ chronic Achilles tendon ruptures. A clinical data of 14 patients with Myerson type Ⅱ and Ⅲ chronic Achilles tendon ruptures between March 2020 and June 2024 was retrospectively analyzed. All Achilles tendon defects were repaired with the free fascia lata assisted by ICGA during operation. There were 12 males and 2 females with an average age of 45.4 years (range, 26-71 years). The causes of Achilles tendon rupture included sports injury in 10 cases, Achilles tendon-related tendinopathy in 3 cases, and glass laceration injury in 1 case. The time from Achilles tendon rupture to operation was 4-40 weeks (median, 4.5 weeks). Preoperative MRI examination showed that the defect length of the Achilles tendon was 2-5 cm (mean, 3.2 cm). The operation time and intraoperative blood loss were recorded. The color Doppler ultrasound (CDU) and MRI were taken to observe the foot blood vessels and the tendon healing. The visual analogue scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, Achilles Tendon rupture score (ATRS), and range of motion of the ankle joint were used to estimate the pain and function of ankle joint. All operations of the 14 patients were successfully completed. The operation time ranged from 3.00 to 4.50 hours (mean, 3.60 hours). The intraoperative blood loss ranged from 10 to 50 mL (mean, 36.4 mL). After operation, 1 patient had exudation at the recipient site, which healed after dressing change; the other incisions healed by first intention. All incisions at the donor sites healed by first intention. All patients were followed up 6-36 months (mean, 11.4 months). The CDU of the foot at 1 month after operation showed that the blood flow signal of the perforating vessels of the fascia lata flap was clear. The ankle MRI at 2 months after operation showed the good continuity of the Achilles tendon. No complication such as the Achilles tendon re-rupture, ankle stiffness, or scar contracture occurred during follow-up. Compared with preoperative score, the AOFAS score, ATRS score, and plantar flexion range of motion significantly increased at 1, 3, and 6 months after operation ( P<0.05), while the VAS score and dorsiflexion range of motion significantly decreased ( P<0.05). The AOFAS score, ATRS score, and VAS score at 3 and 6 months further improved when compared with those at 1 month ( P<0.05); however, there was no significant difference in the range of motion of the ankle joint ( P>0.05). There was no significant difference in above indicators between 3 and 6 months after operation ( P>0.05). The treatment of Myerson type Ⅱ and Ⅲ chronic Achilles tendon ruptures with free fascia lata flaps under the guidance of ICGA has the advantages of precise design, fast healing, and a wide range of adaptability.

Operative management of chronic Achilles tendon ruptures is challenging, and numerous techniques have been described. Risk of infection and wound breakdown have been described after open techniques, and minimally invasive methods have been proposed to avoid them. The aim of this study was to describe the clinical and radiological results obtained after endoscopic flexor hallucis longus (FHL) tendon transfer in patients with chronic Achilles tendon rupture. Between 2012 and 2015, a total of 22 patients were endoscopically treated for chronic Achilles tendon rupture. Mean age was 69 years (range, 59-84 years). Mean follow-up was 30.5 months (range, 18-46 months). Preoperative magnetic resonance imaging (MRI) was obtained and tendon gap measured. An MRI was obtained at 9 to 12 months following surgery to evaluate Achilles tendon changes. Preoperative MRI examination showed a mean tendon gap of 6.3 cm (range, 3-10.7 cm). The MRI control was obtained only in 12 patients, and a normal or close to normal Achilles tendon was observed in all but 1 patient. The mean American Orthopaedic Foot & Ankle Society score increased from 55 preoperatively (range, 26-75) to 91 (range, 74-100) at final follow-up. All patients returned to their daily activities without difficulties. No patients reported complaints or symptomatic deficits of great toe flexion strength. No major complications were encountered. Chronic Achilles tendon ruptures were successfully treated by an all-endoscopic procedure. The endoscopically assisted FHL transfer provided excellent results while benefiting from the minimally invasive procedure advantages. However, it entailed some technical challenges and may not be suitable for less experienced surgeons. Level IV, retrospective case series.

Functional outcome of gastrocnemius advancement flap augmented with short flexor hallucis longus tendon transfer in chronic Achilles tear

The purpose of this study was to introduce a novel operative technique and to evaluate the clinical outcomes in a cohort of patients with missed or neglected Achilles tendon ruptures. Fifteen consecutive patients with missed complete Achilles tendon ruptures and 5-cm or larger gaps had reconstruction with V-Y lengthening and flexor hallucis longus tendon transfer through a single incision. The patients were evaluated at an average of 106 weeks after surgery. At the time of followup, all patients were assessed with regard to their self-reported level of satisfaction and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. Ankle strength and active range of motion were evaluated using Biodex (Biodex Medical Systems, Shirley, NY) isokinetic dynamometry. In addition, seven patients were evaluated using diagnostic ultrasound. We found a 7.7 N-m (-22.3%) loss of plantarflexion torque at 60 degrees/sec and a 3.5 N-m (-13.5%) loss of plantarflexion torque at 120 degrees/sec, as well as a 5 degrees loss of active range of motion. AOFAS scores were all good to excellent, with an average score of 94.1 of 100. All patients were satisfied with their outcomes (rated good or very good). Excellent exposure of the Achilles tendon repair was obtained with ultrasound. For patients with missed or neglected Achilles tendon rupture with a rupture gap of at least 5 cm, operative repair using V-Y lengthening and flexor hallucis longus tendon transfer through a single incision technique achieved a high percentage of satisfactory results.

The Achilles tendon, the body's largest tendon, is often vulnerable to rupture, primarily as a result of sudden dorsiflexion of a plantar-flexed foot. This injury predominantly affects individuals in their youth and middle age. In this case series, we describe three middle-aged men with neglected insertional Achilles tendon ruptures, each presenting an average 10 cm defect. They underwent a surgical procedure involving flexor hallucis longus (FHL) tendon transfer with concurrent gastrocnemius augmentation. The FHL tendon was repositioned proximally and securely tenodesed to the proximal stump of the excised Achilles tendon. Following this intervention, substantial clinical improvements were observed at the six-month follow-up, with the American Orthopaedic Foot and Ankle Society (AOFAS) score improving from 35 to 85 and the Visual Analog Scale (VAS) pain score decreasing from 8 to 2. These results highlight the efficacy of flexor hallucis longus tendon transfer with gastrocnemius augmentation as a superior treatment option for neglected insertional achilles tendon tears characterized by substantial defects, promising improved functional outcomes and pain relief.