Treatment of chronic achilles tendinopathy and ruptures with flexor hallucis tendon transfer: clinical outcome and MRI findings

Does FHL Tendon Transfer Alter the Outcome of Haglund Deformity Treatment by Using Debridement and Ostectomy in Patients Older Than 50 Years? A Single-Blinded Randomized Controlled Trial

Background

Chronic Achilles tendinopathy following Haglund disease is a common ankle condition that is difficult to manage. In this study, we will compare the clinical outcomes of debridement and ostectomy with and without FHL tendon transfer in treating Haglund deformity.

Methods

Forty eligible patients aged >50 years who did not respond to conservative treatment were randomly divided into 2 groups for surgical approach: using flexor hallucis longus (FHL) tendon transfer (FHL group) or "standard procedure" (control group). The main surgical treatment included debridement and ostectomy. AOFAS and VISA-A scores were obtained from all patients pre- and postoperatively.

Results

Twenty patients were assigned to each of the 2 groups and were observed for at least 1 year. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle hindfoot scores and the Victorian Institute of Sports Assessment self-administered Achilles (VISA-A) questionnaires scores improved more in the FHL group; however, the average difference in the change in scores did not reach the levels previously reported for minimal clinically important differences. Surgical complications and hallux function were not significantly different between the 2 groups.

Conclusion

We found that FHL tendon transfer may improve the clinical outcome scores of Achilles tendon treatment in patients aged >50 years using debridement and ostectomy. However, tendon transfer increases the time of surgery and creates additional skin incisions, which may cause more short-term wound complications, and the significance of the differences in outcome improvement may not be clinically meaningful.

Level of Evidence

Level II, grade A recommendation.

Postoperative Return to Play and the Role of Imaging

Return to play (RTP) following surgery is a complex subject at the interface of social and internal pressures experienced by the athlete, psychological readiness, and intrinsic healing of the surgically repaired structures. Although functional testing, time from surgery, clinical examination, and scoring metrics can help clarify an athlete's readiness to return to sport, imaging can allow for a more direct assessment of the structures in question. Because imaging is often included in the diagnostic work-up of pain following surgery, the radiologist must be familiar with the expected postsurgical imaging appearance, as well as the associated complications. We briefly review such findings following anterior cruciate ligament reconstruction, Achilles tendon repair, syndesmotic fixation, and ulnar collateral ligament reconstruction in the context of the athlete, highlighting issues related to RTP.

Strength and Functional Outcomes Following Achilles Tendon Reconstruction With Hamstring Tendon Autograft Augmentation

BACKGROUND

The proposed advantages of hamstring autograft reconstruction when compared to alternative procedures, such as flexor hallucis longus (FHL) transfer, V-Y lengthening, and allograft reconstruction, are improved healing and reproduction of normal tendon biomechanics and reduced morbidity within the foot and ankle. In this study, we examined the effect of Achilles tendon reconstruction using hamstring autografts on strength and functional outcomes.

METHODS

Patients who underwent Achilles repair with a hamstring autograft for insertional or midsubstance tendinopathy, delayed diagnosis of rupture, or infection after primary repair were evaluated for inclusion. Forty-six patients were identified; 12 further augmented with an FHL transfer are included in the analysis. Isokinetic testing was completed with a Biodex dynamometer under supervision of a physical therapist masked to surgical side. Pre- and postoperative Foot and Ankle Outcome Scores (FAOS, before March 2016) or Patient-Reported Outcomes Measurement Information System (PROMIS, after March 2016) surveys were collected.

RESULTS

For knee flexion, peak torque was not significantly different when comparing operative and nonoperative sides at 180 degrees/second (45.38 Nm vs 45.96 Nm; P = .69) nor at 300 degrees/second (44.2 Nm vs 47.02 Nm; P = .069). Knee extension absolute peak torque was only found to be significantly weaker on the operative side at the faster testing (75.5 Nm vs 79.56 Nm; P < .05). Peak ankle plantarflexion torque was significantly weaker on the operative side at both the slower speed (60 degrees/second: 39.9 Nm vs 48.76 Nm; P < .005) and the faster speed (120 degrees/second: 31.3 Nm vs 40.7 Nm; P < .001). Average power for ankle plantarflexion did not differ significantly from the operative side to the nonoperative side in the slower test (26.46 W vs 27.48 W; P = .60) but did significantly differ on the faster test (32.13 W vs 37.63 W; P = .041). At an average of 19.9 months postoperation, all physical function and pain-related patient-reported outcome scores showed clinically and statistically significant improvement.

CONCLUSION

Achilles reconstruction with a hamstring autograft ± FHL transfer allowed patients with severe Achilles pathology to return to good subjective function, with modest deficits in calf strength compared with the uninjured side. Overall knee flexion strength did not appear impaired. These results suggest that hamstring autograft reconstruction is a viable method to treat these complex cases involving a lack of healthy tissue, allowing patients to return to symptom-free physical function and athletic activity.

LEVEL OF EVIDENCE

Level IV, case series.

Surgical management of chronic Achilles tendon rupture: evidence-based guidelines

BACKGROUND

Chronic Achilles tendon ruptures (CATR) often require surgical intervention to restore function. Despite numerous treatment modalities available, the optimal management strategy remains controversial given the limited high-quality evidence available. This article aims to provide evidence-based guidelines for the surgical management of CATR through a comprehensive systematic review of the available data. The consensus reached by synthesizing the findings will assist clinicians in making informed decisions and improving patient outcomes.

METHODS

A group of 9 foot surgeons in three continents was consulted to gather their expertise on guidelines regarding the surgical management of CATR. Following the proposal of 9 clinical topics, a thorough and comprehensive search of relevant literature published since 1980 was conducted for each topic using electronic databases, including PubMed, MEDLINE, and Cochrane Library, to identify relevant studies published until 1 October 2023. All authors collaborated in drafting, discussing, and finalizing the recommendations and statements. The recommendations were then categorized into two grades: grade a (strong) and grade b (weak), following the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) concept. Additionally, feedback from 21 external specialists, who were independent from the authors, was taken into account to further refine and finalize the clinical guidelines.

RESULTS

Nine statements and guidelines were completed regarding surgical indications, surgical strategies, and postoperative rehabilitation protocol.

CONCLUSION

Based on the findings of the systematic review, this guideline provides recommendations for the surgical management of CATR. We are confident that this guideline will serve as a valuable resource for physicians when making decisions regarding the surgical treatment of patients with CATR.

"Foot peak pressures are comparable to normal foot after flexor hallucis longus transfer for chronic retracted tendo-achilles tear: A pedobarographic analysis of normal foot versus affected foot"

INTRODUCTION

Foot pressure changes and morbidity after flexor hallucis longus (FHL) transfer in chronic retracted tendoachilles (TA) tears have not been documented. The primary aim of our study is to analyze the peak pressure changes in various zones of the foot at each successive follow-up in the affected foot versus normal foot. The secondary aim is to determine FHL tendon healing and muscle hypertrophy.

METHODS

This is a prospective study of 46 patients who underwent FHL augmentation for chronic retracted TA tears (between 2019 and 2022). Included TA tear > 6 weeks duration and retraction > 2.5 cm. Excluded open TA tear, < 6 weeks and retraction < 2.5 cm. Depending on the amount of retraction, FHL augmentation combined with TA repair/VY plasty/turn-down-plasty. Functional outcome was analyzed with AOFAS hallux metatarsophalangeal scale. Pedobarographic analysis was done pre-operatively and at 3, 6, 9 months, 1 year and at the final follow-up. Parameters studied included forefoot peak pressure (FFPP), hindfoot peak pressure (HFPP), great toe peak pressure (GTPP), first Mmeta-tarso phalangeal peak pressure (MTPP), area under the pedobarograph and maximum force. At final follow-up MRI was done to assess FHL healing and hypertrophy. Statistical analysis was done for these parameters using appropriate tests.

RESULTS

Study involved 29 male and 17 female patients, mean age 49.5 years (33-65 years) and mean follow-up 26.8 months (14-38.4months). Mean hallux MTP-AOFAS score increased from 46.04 ± 7.31 preoperatively to 96.17 ± 3.22 at the final follow-up (P < 0.01). There was gradual improvement noted in FFPP, GTPP, MTPP Peak pressures at subsequent follow-ups, and by the end of 1-year foot pressures were comparable to normal side FFPP (8.02 ± 3.8 N/cm2 to 31.35 ± 3 N/cm2), GTPP(30.78 ± 13.01 N/cm2 to23.17 ± 7.5 N/cm2), MTPP(5.22 ± 2.64 N/cm2 to 23.3 ± 9.6 N/cm2). Initial high HFPP showed decline in subsequent follow-up and restored back to normal HFPP (36.91 ± 5.7 N/cm2 to 25.09 ± 3.7 N/cm2). Changes in pressures were statistically significant (< 0.001). Six patients had superficial wound infections healed with antibiotics. 23 patients who underwent a post-operative MRI showed a mean of 27 mm muscle thickness and 7.1 mm tendon thickness with complete incorporation of the FHL.

CONCLUSION

Foot peak pressures though initially deranged, are restored and comparable to normal foot after FHL transfer for chronic retracted TA tear. FHL hypertrophy is observed at the muscle thickness and at the distal tendon and provides adequate strength to repair and restore foot pressures.

LEVEL OF EVIDENCE III

Prospective comparative study (normal versus operated foot).

The compensatory hypertrophy of transferred flexor hallucis longus tendon for insertional Achilles tendinopathy: a retrospective MRI study

Flexor hallucis longus (FHL) transfer is an effective surgery in treating insertional Achilles tendinopathy (IAT). However, limited data exist regarding the post-surgery changes in the transferred FHL. The study aimed to compare the sequential changes and hypertrophy of FHL after isolated FHL transfer (FHLT). We retrospectively enrolled patients who underwent isolated FHLT for insertional Achilles pathology from 2015 to 2020 and divided them into two groups based on whether reattachment of the residue Achilles stump to the FHL was performed or not. We recorded demographic characteristics, MRI parameters, and functional outcome. We also analyzed the correlation between the collected data and FHL hypertrophy. Results revealed no significant differences in most MRI parameters of FHL and functional outcomes between the groups. However, the fat distribution within the FHL showed significant reduction and notable 20.2% hypertrophy after FHLT. Interestingly, the hypertrophy of the FHL was significantly more pronounced in the non-reattached group. Furthermore, we observed a positive correlation between the follow-up period and FHL hypertrophy. In conclusion, the FHL demonstrated significant enlargement over time following FHLT. The compensatory hypertrophy of the transferred FHL was particularly evident and the cumulative incidences of FHL enlargement over time were higher in the non-reattached groupcompared to reattached group. However, both reattachment and non-reattachment of Achilles stump on FHL transfer for insertional Achilles tendinopathy carried similar postoperative functional outcomes.

Achilles tendon thickening does not affect elasticity and functional outcome after surgical repair of Achilles rupture: A retrospective study

PURPOSE

Previous studies have confirmed that Achilles tendon occurs Achilles thickening after repair surgery of the rupture. Although this mechanism has been elucidated in the laboratory, there are few reports on its impact on clinical function. We designed a retrospective study to investigate the Achilles thickening after Achilles tendon rupture repair and its correlation between the elasticity and postoperative function.

METHODS

In this retrospective analysis, patients who underwent surgical treatment for acute Achilles tendon rupture from April 2016 to April 2020 were included. All the patients were regularly followed up at 3 months, 1 year, and 2 years after surgery. American Orthopaedic Foot Ankle Surgeon (AOFAS) scale and Leppilahti score were used to evaluate functional outcomes. Achilles elasticity was measured by ultrasound shear wave of elasticity. Achilles thickening was calculated as maximal transverse and longitudinal diameter in cross-sectional plane of magnetic resonance scan. Sample t-tests was used for different follow-up periods. Correlation between Achilles thickening and other factors were analyzed using Pearson's method. p < 0.05 indicates a statistically significant difference.

RESULTS

AOFAS scale and Leppilahti score at 1 year were significantly higher than at 3 months postoperatively (both p < 0.001). These functional scales were also improved at 2-year follow-up significantly (both p < 0.001). The dorsiflexion difference showed gradually recovery in each follow-up period (t = -17.907, p < 0.001). The elasticity of the Achilles appeared to continuously decreases during the postoperative follow-up period in all position sets (p < 0.001). In thickening evaluation, the cross-sectional area of the thickest plane of Achilles was significantly higher at 1 year postoperatively (310.5 ± 25.2) mm2 than that at 3 months postoperatively ((278.0 ± 26.2) mm2, t = -8.219, p < 0.001) and became thinner in 2-year magnetic resonance scan ((256.1 ± 15.1) mm2, t = 16.769, p < 0.001). The correlations between Achilles thickening, elasticity, and functional outcome did not show statistical significance (p > 0.05) in every follow-up period.

CONCLUSION

Achilles tendon thickens after surgery in the 1st year, but begins to gradually return to thinning about 2 years after surgery. There was no significant correlation between the increase and decrease of thickening and the patients' clinical function scores, Achilles elasticity, and bilateral ankle dorsiflexion difference.

Long-term outcome of flexor hallucis longus tendon transfer for chronic Achilles tendon rupture with large defect: A retrospective series

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.

Minimally invasive surgeries for insertional Achilles tendinopathy: A commentary review

Studies of minimally invasive surgery for insertional Achilles tendinopathy are limited. To establish this surgery, the following techniques must be minimally invasive: Exostosis resection at the Achilles tendon insertion, debridement of degenerated Achilles tendon, reattachment using anchors or augmentation using flexor hallucis longus (FHL) tendon transfer, and excision of the posterosuperior calcaneal prominence. Studies on these four perspectives were reviewed to establish minimally invasive surgery for insertional Achilles tendinopathy. Techniques for exostosis resection were demonstrated in one case study, where blunt dissection around the exostosis was performed, and the exostosis was resected using an abrasion burr under fluoroscopic guidance. Techniques for debridement of degenerated Achilles tendon were demonstrated in the same case study, where the space left after resection of the exostosis was used as an endoscopic working space, and the degenerated Achilles tendon and intra-tendinous calcification were debrided endoscopically. Achilles tendon reattachment techniques using suture anchors have been demonstrated in several studies. However, there are no studies on FHL tendon transfer techniques for Achilles tendon reattachment. In contrast, endoscopic posterosuperior calcaneal prominence resection is already established. Additionally, studies on ultrasound-guided surgeries and percutaneous dorsal wedge calcaneal osteotomy as minimally invasive surgery were reviewed.

Presurgical Perspectives and Post-treatment Evaluation of Achilles Tendon Injuries

The Achilles is a commonly injured tendon, prone to degeneration and tear. Achilles tendon treatment ranges from conservative management to injections, tenotomy, open versus percutaneous tendon repair, graft reconstruction, and flexor hallucis longus transfer. Interpreting postoperative imaging of the Achilles tendon is a difficult task for many providers. This article clarifies these issues by presenting the imaging findings following standard treatments and depicts expected appearance versus recurrent tear and other complications.

Effect of Symptom Duration on Injury Severity and Recovery in Patients With Achilles Tendinopathy

Background

Achilles tendinopathy is a common overuse condition. Distinguishing between early- and late-stage tendinopathy may have implications on treatment decisions and recovery expectations.

Purpose

To compare the effects of time and baseline measures of tendon health on outcomes among patients with varying symptom durations after 16 weeks of comprehensive exercise treatment.

Study Design

Cohort study; Level of evidence, 3.

Methods

Participants (N = 127) were categorized into 4 groups based on the number of months since symptom onset: ≤3 months (n = 24); between >3 and ≤6 months (n = 25); between >6 and ≤12 months (n = 18); or >12 months (n = 60). All participants received 16 weeks of standardized exercise therapy and pain-guided activity modification. Outcomes representing symptoms, lower extremity function, tendon structure, mechanical properties, psychological factors, and patient-related factors were assessed at baseline and at 8 and 16 weeks after the initiation of exercise therapy. Chi-square tests and 1-way analysis of variance were used to compare baseline measures between groups.Time, group, and interaction effects were evaluated using linear mixed models.

Results

The mean age of the participants was 47.8 ± 12.6 years, 62 participants were women, and symptoms ranged from 2 weeks to 274 months. No significant differences were found among symptom duration groups at baseline for any measure of tendon health. At 16 weeks, all groups demonstrated improvements in symptoms, psychological factors, lower extremity function, and tendon structure, with no significant differences among the groups (P > .05).

Conclusion

Symptom duration did not influence baseline measures of tendon health. Additionally, no differences were observed among the different symptom duration groups in response to 16 weeks of exercise therapy and pain-guided activity modification.

Evaluation of Flexor hallucis tendon transfer in chronic insertional Achilles tendinopathy in over 50-year-old population using validated ankle scores

PURPOSE

Chronic insertional Achilles tendinopathy is a common pathology in the over 50 years old population. Patients not relieved with conservative treatment had to undergo surgical intervention for the management. This study evaluates the clinical outcome of FHL transfer in such patients using validated ankle functional scores.

METHOD

It is a retrospective study including 20 patients of either gender managed with debridement of the distal degenerative remnant Achilles tendon fibers either at the insertion site or the distal end of the torn tendon, resection of Haglund deformity with FHL transfer, and reattachment of Achilles tendon. The average age of the patients was 56.55 + 11 years (50-77 years) followed by over 35.6 months (Range 22-48months). The preoperative FAAM, FADI, SF 36, VAS, and AOFAS scores were calculated and followed every 6 months. The plantarflexion and dorsiflexion of the ankle were also recorded preoperatively and at follow-up visits.

RESULTS

All the patients were operated on by a single surgeon (MS) with the same surgical technique, implant, and rehabilitation protocol. All the patients were followed for an average of 35.6 months (Range 22-48 months). All the ankle scores, FAAM, FADI, SF36, VAS, and AOFAS improved in follow-ups. The mean plantarflexion and dorsiflexion were 39.30⁰+ 4.9⁰ and 12.5⁰+ 4.7⁰ respectively. Three patients had minor wound complications. All the patients returned to activities of daily living.

CONCLUSION

FHL transfer in elderly patients with insertional Achilles tendinopathy improves the validated ankle functional scores and decreases pain significantly. Furthermore, randomized studies with a larger study population and longer follow-ups may ascertain the beneficial effects.

Local Tendon Transfers for Chronic Ruptures of the Achilles Tendon: A Systematic Review

Introduction: A rupture of the Achilles tendon with a delay in diagnosis or treatment for more than 6 weeks is considered a chronic tear. Local tendon transfer procedures can be used in chronic Achilles tendon ruptures. This study evaluated the outcome, return to sport, and complications of local tendon transfer in patients with chronic Achilles tendon rupture. Material and methods: The present study was conducted according to the PRISMA 2020 guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in November 2022. Results: Data were retrieved from 23 articles (463 patients, mean age 50.9 ± 13.5 years). The mean duration of the follow-up was 58.3 ± 76.8 months. The VAS improved by 1.8/10 (p = 0.4), the AOFAS by 33.4/100 (p < 0.0001), and the ATRS by 32.5/100 (p = 0.0001) points. Patients were able to return to sport after a mean of 19.6 ± 16.4 weeks. A total of 79% of patients were able to return to their previous activities. The rate of complications was 13.3%. Conclusions: The use of local tendon transfer for chronic Achilles tendon ruptures using the FHL or PB tendon resulted in good clinical outcomes and a reliable return to daily activities and sports. The rate of complications reflects the chronicity of the condition and the technical complexity of the procedure. Level of evidence: IV.

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.

Failed Surgery for Achilles Tendinopathy

Treatments of Achilles tendinopathy continue to evolve. The body of literature is inadequate to provide a comprehensive guide to evaluation and treat failed surgeries. Issues related to failed surgical treatment may be divided into infection/wound issue, mechanical failure, and persistent pain. Awareness of the potential problems described in this article will allow surgeons to have a foundation in clinical assessment and making accurate diagnoses. Various surgical treatment options are available and should be executed carefully to treat individualized patient conditions.

Influence of mechanical and TGF-β3 stimulation on the tenogenic differentiation of tonsil-derived mesenchymal stem cells

Background

Organogenesis from tonsil-derived mesenchymal cells (TMSCs) has been reported, wherein tenogenic markers are expressed depending on the chemical stimulation during tenogenesis. However, there are insufficient studies on the mechanical strain stimulation for tenogenic cell differentiation of TMSCs, although these cells possess advantages as a cell source for generating tendinous tissue. The purpose of this study was to investigate the effects of mechanical strain and transforming growth factor-beta 3 (TGF-β3) on the tenogenic differentiation of TMSCs and evaluate the expression of tendon-related genes and extracellular matrix (ECM) components, such as collagen.

Results

mRNA expression of tenogenic genes was significantly higher when the mechanical strain was applied than under static conditions. Moreover, mRNA expression of tenogenic genes was significantly higher with TGF-β3 treatment than without. mRNA expression of osteogenic and chondrogenic genes was not significantly different among different mechanical strain intensities. In cells without TGF-β3 treatment, double-stranded DNA concentration decreased, while the amount of normalized collagen increased as the intensity of mechanical strain increased.

Conclusions

Mechanical strain and TGF-β3 have significant effects on TMSC differentiation into tenocytes. Mechanical strain stimulates the differentiation of TMSCs, particularly into tenocytes, and cell differentiation, rather than proliferation. However, a combination of these two did not have a synergistic effect on differentiation. In other words, mechanical loading did not stimulate the differentiation of TMSCs with TGF-β3 supplementation. The effect of mechanical loading with TGF-β3 treatment on TMSC differentiation can be manipulated according to the differentiation stage of TMSCs. Moreover, TMSCs have the potential to be used for cell banking, and compared to other mesenchymal stem cells, they can be procured from patients via less invasive procedures.

Patient reported outcomes and satisfaction following single incision Flexor Hallucis Longus (FHL) augmentation for chronic Achilles tendon pathologies

BACKGROUND

Various procedures exist to augment or reconstruct the Achilles tendon (AT) in patients suffering from chronic pathologies. The aim of this study is to assess patient reported outcomes and satisfaction following single incision FHL augmentation using a short tendon harvest with interference screw fixation.

METHODS

This is a multicentre case series where postoperative patient reported outcome and satisfaction scores were collected on 30 patients. Outcome measures included EQ-5D, EQ-VAS, Achilles Tendon Rupture Scores (ATRS), and satisfaction scores. Scores were also collected on the unaffected limbs for comparison.

RESULTS

Mean patient age was 61 years (range 40-79, SD 11). Mean EQ-5D index value was 0.750 (0.100-1.00, SD 0.238), and mean EQ-VAS score was 74 (36-99, SD 15), at a mean follow-up of 57 months (4-118, SD 32). For patients with ≥24 months' follow-up, a mean deficit of 16 ATRS points was found between the operated and unaffected limb. Overall satisfaction was over 86%. In cases of chronic AT rupture, younger age and increasing time from initial injury to surgery were predictors of greater residual deficit. No serious complications or failures occurred.

CONCLUSIONS

FHL augmentation using short tendon harvest and interference screw fixation is a safe treatment option. It appears to take at least 24 months to functionally recover following this procedure, and despite a residual function deficit, there is a high level of patient satisfaction. Further studies are required to determine optimal patient selection and timing of surgery.

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.

Management of chronic Achilles ruptures: a scoping review

PURPOSE

This scoping review aims to systematically map and summarise the available evidence on the management of chronic Achilles ruptures, whilst identifying prognostic factors and areas of future research.

METHODS

A scoping review was performed according to the frameworks of Arksey and O'Malley, Levac and Peters. A computer-based search was performed in PubMed, Embase, EmCare, CINAHL, ISI Web of Science and Scopus, for articles reporting treatment of chronic Achilles ruptures. Two reviewers independently performed title/abstract and full text screening according to pre-defined selection criteria.

RESULTS

A total of 747 unique articles were identified, of which 73 (9.8%) met all inclusion criteria. A variety of methods are described, with flexor hallucis longus tendon transfer being the most common. The most commonly reported outcome is the American Orthopaedic Foot and Ankle Society (AOFAS) score, although 16 other measures were reported in the literatures. All studies comparing pre- and post-operative outcomes reported significant post-treatment improvement. Complications were reported in 50 studies, with an overall pooled complication rate of 168/1065 (15.8%).

CONCLUSION

Although beneficial results were reported following a variety of techniques, comparison between these is challenging due to the low-level study designs used and confounding factors such as treatment delay and tendon gap size. Further research comparing the efficacy of different techniques is required in order to facilitate the development of an evidence-based treatment protocol. Such work would allow clinicians to better understand the suitability of the large variety of reported techniques and select the optimal strategy for each individual patient.

Endoscopic Flexor Hallucis Longus Transfer for the Management of Acute Achilles Tendon Ruptures: A Prospective Case Series Report With a Minimum of 18 Months' Follow-Up

Acute Achilles tendon rupture can be treated either surgically or nonsurgically. The flexor hallucis longus (FHL) has been used successfully in patients with large chronic Achilles tendon defects. The aim of this study was to describe the clinical outcomes of isolated endoscopic FHL transfer in patients with acute Achilles tendon ruptures at a minimum follow-up of 18 months. Fifty-six male patients with an average age of 36.3 years who underwent endoscopic FHL transfer as a treatment for acute Achilles tendon ruptures were included. Follow-up was for a mean (± standard deviation) of 27.5 ± 7.29 months. At 18 months postoperatively, the Achilles tendon total rupture score mean was 95 ± 4.26, and the American Orthopaedic Foot and Ankle Society score was a mean of 96.4 ± 4.31. The median value for FHL tendon dynamometry on the surgical side was 95.72 (range 70.1 to 142), and 100.7 (range 68 to 161) for the nonoperated side. Mean ankle plantarflexion strength at 18 months was 19.19 ± 2.55 kg • m compared with the uninjured side of 19.27 ± 2.16 kg • m. Relative Achilles tendon resting angle showed a mean of -0.25° ± 2.43°. Magnetic resonance imaging performed at a minimum of 18 months postoperatively showed a homogeneous continuous Achilles tendon signal for 43 patients and heterogeneous signal intensity in 13 patients (23.21%). No patients reported any great toe complaints or symptomatic deficits of flexion strength. No neurovascular or skin complications were encountered. The current study demonstrated satisfactory and comparable results with minimal complications when using the endoscopic FHL tendon transfer in surgical management of acute Achilles tendon ruptures, compared with the currently used methods.

Arthroscopic, Single-Incision, and Double-Incision Approaches to Flexor Hallucis Longus Tendon Transfer Following Achilles Tendon Rupture: A Literature Review

Achilles tendon rupture is a common athletic injury that results in a painful and antalgic gait. Flexor hallucis longus tendon transfer through arthroscopic, single-incision, or double-incision techniques is used as a treatment approach to address this rupture; however, no studies have compared postoperative complications between these three techniques. A systematic search of published articles was conducted using keywords "Achilles rupture," "flexor hallucis tendon," "transfer," and "recovery." Articles were then selected based on their title, abstract, and content following full-text review. From each article's reported surgical outcomes, a comparison was made between arthroscopic and single- and double-incision postoperative complications using a χ2 test with significance set at a value of P < .05 followed by post hoc analysis. The arthroscopic approach maintained the lowest rate of postoperative complications, followed by the single- and double-incision techniques. A significant difference in the number of postoperative complications was found between all incisional approaches. The pairwise comparisons, however, could not identify which incisional approaches significantly differed between each other. A reduction in postoperative complications places arthroscopy and the single-incision techniques as the preferred approaches for flexor hallucis longus tendon transfer following an Achilles tendon rupture. Although current literature shows arthroscopy to be superior to single- and double-incision methods, this review demonstrates the need for a greater number of published cases using arthroscopy to establish significance regarding postoperative complications.

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.

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.

Clinical outcomes of chronic Achilles tendon rupture treated with flexor hallucis longus grafting and flexor hallucis longus grafting plus additional augmentation: A meta-analysis

BACKGROUND

The treatment of chronic Achilles tendon rupture is still controversial. Many surgical procedures have been proposed and claim to have good post-operative clinical outcomes. These techniques include direct repair, V-Y flap, turndown flap, peroneus brevis tendon graft, flexor digitorum longus graft, FHL graft, semitendinosus graft, gracilis tendon graft or synthetic material. The two surgical techniques that are widely used include FHL grafting and the combination of FHL grafting plus additional augmentation. This meta-analysis was conducted with the purpose of comparing clinical outcomes of flexor hallucis longus (FHL) grafting and the combination of FHL grafting with additional augmentation techniques in the treatment of chronic Achilles tendon rupture.

METHODS

Systematic literature searches were conducted on Medline, Embase and Scopus from their inception to April 4, 2019, and proceedings of reference list and scientific meetings were also searched. Relevant clinical studies (e.g., observational, cross-sectional, cohort or randomized controlled trial (RCT)) that reported AOFAS (American Orthopedic Foot Ankle Score) and postoperative complications of either technique were identified.

RESULTS

Six studies (N = 68) were included for the analysis of FHL, and six studies (N = 124) were included for analysis of FHL with augmentation. A pooling of mean and standard deviation of preoperative and postoperative AOFAS were 57.09 (3.63), 92.97 (22.67) in FHL group and 66.92 (3.16), 95.25 (4.71) in FHL with additional augmentation group respectively. The pooled UMD of AOFAS in FHL with additional augmentation were 2.28 (-1.86, 6.42) scores higher when compared to the FHL group. The prevalence of complications in FHL and FHL with additional augmentation were 14 (N = 120) and 10 (N = 63) patients. The chance of having complications of FHL with additional augmentation group was 0.74 (95% CI: 0.35, 1.56) lower than FHL group. However, there is no statistically significant difference.

CONCLUSIONS

FHL with additional augmentation group has higher foot function scores (AOFAS) and lower complications when compared to the FHL group. However this did not reach to statistically significant. Further research that assesses a larger sample size of RCTs is necessary to further evaluate FHL with additional augmentation and FHL in the treatment of chronic Achilles tendon rupture.

Revision Surgery for the Achilles Tendon

Treatment of Achilles tendon ruptures may be surgical or nonsurgical depending on health, history, age, acuity, and severity of the injury. With chronic or revisional injuries, the best method often requires an open repair with reconstructive soft tissue procedures. Revision surgery can be challenging because of the complexity involving tendinous deficits with nonviable and friable tissue. Surgical treatment is based on tendon approximation, size of the defect, tendon integrity, and functional demands. The goal is to restore anatomic and physiologic tension, provide adequate strength for proper ambulation, optimize functional return to activity, decrease pain, and decrease complications.

Post-operative MRI and US appearance of the Achilles tendons

The Achilles tendon is one of the most commonly ruptured tendons in the human body. Minimally invasive and open surgical repairs are commonly undertaken to manage acute Achilles ruptures. This article describes the postoperative imaging findings and their evolution after surgery. Ultrasound and magnetic resonance imaging provide crucial information regarding the morphology, structure, vascularization and mobility of the Achilles tendon on the surrounding planes. Morphologically, a repaired tendon is physiologically larger and wider than an intact one, with a loss of its fibrillary structure; the presence of surgical material in the context of the tendon is normal after the rupture has been repaired. After surgery, the tendon is more vascularized in power-Doppler imaging. Elastography and diffusion tensor Imaging are innovative tools which allow for the visualization of microstructural abnormalities not apprehensible using conventional imaging techniques. A treated Achilles tendon is unlikely to regain a normal imaging appearance, and the health care professional must distinguish between postoperative findings and actual pathological features. In this context, clinical examination still reigns supreme.

Comparison of Gastrocnemius Turn Flap and Hamstring Graft for the Treatment of Kuwada Type 3 Chronic Ruptures of the Achilles Tendon: A Retrospective Study

Background:

Chronic Achilles tendon rupture is challenging to repair, and many procedures have been suggested to fill the gap that separates the distal and proximal ends of the ruptured tendon.

Purpose:

To compare clinical outcomes between the free hamstring graft (HG) and gastrocnemius turn flap (GTF) procedures in the treatment of chronic Achilles tendon rupture.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This retrospective study included 26 patients (25 males, 1 female; mean age, 36.7 years; range, 22-53 years) with Kuwada type 3 chronic rupture of the Achilles tendon. A total of 11 patients underwent GTF surgery, whereas 15 patients underwent HG surgery. Follow-up assessments were conducted at 3, 6, and 12 months postoperatively.

Results:

The complication rate was significantly higher in the GTF group compared with the HG group (27.2% vs 6.6%, respectively; χ² = 12.462; P = .001). At the 3-month follow-up, the degree of ankle dorsiflexion was significantly higher in the HG group than in the GTF group (t = 3.144; P = .004). At 6-month and 1-year follow-up, no significant differences in ankle function were seen between the 2 groups.

Conclusion:

Hamstring tendon graft is associated with better early recovery of dorsiflexion compared with GTF. The long-term clinical outcomes of these 2 procedures are similar.

Modified Percutaneous Achilles Tendon Lengthening by Triple Hemisection for Achilles Tendon Contracture

Background

Both percutaneous Achilles tendon lengthening by triple hemisection and the traditional open Z-lengthening are effective methods for Achilles tendon contracture. This study aims to evaluate the efficacy and safety of this new therapeutic method, which is based on the percutaneous sliding technique with three hemi-cuts in the tendon, as compared with the traditional open Z-lengthening.

Methods

Retrospective analysis of the Achilles tendon contracture cases in our hospital between January 2010 and September 2016 was conducted. Twenty-five cases received percutaneous Achilles tendon lengthening (group A), and 30 patients who underwent open Z-lengthening during the same period were in the control group (group B). Operative time and hospital stay were statistically analyzed. Incision complication, equinus recurrence rate and Achilles tendon rupture morbidity were recorded. The function was assessed by American Orthopaedic Foot & Ankle Society (AOFAS) score. All cases in group A received Magnetic Resonance Imaging (MRI) of ankle preoperatively and in the follow-ups.

Results

The mean follow-up period was 42.04 months in group A and 61.7 months in group B. The entire operative time and the mean hospitalization days were lower in group A than in group B. No incision and infection complication occurred in group A. The infection rate in group B was 3.3%. Equinus recurrence rate was 4% in group A and the equinus recurrence rate in group B was 21.4%. In group A, the mean AOFAS score increased from 64 ± 10.16 points preoperatively to 96.08 ± 3.17 at final follow-up, while the score in group B increased from 63.48 ± 6.2 points to 85.4 ± 10.3. MRI showed continuity of the Achilles tendon and homogeneous signal in group A.

Conclusion

Modified surgery can significantly reduce the risk of Achilles tendon rupture, provide better balance in soft tissue strength between ankle dorsiflexion and ankle plantarflexion, helping to avoid recurrence of the deformity.

Endoscopic Flexor Hallucis Longus Tendon Transfer for Reconstruction of the Achilles Tendon Rupture in High-Risk Patients: A Case Series

The neglected Achilles tendon rupture requires surgical reconstruction for the best functional outcome. According to the current literature, there are many reconstructive options available that demonstrate acceptable functional results in most cases. These procedures require large incisions, leading to potential wound-healing complications. Therefore, these procedures may not be suitable for patients who are at high risk for wound-healing problems. A minimally invasive approach is desirable in this situation to decrease the risk of this potential complication. Endoscopic transfer of the flexor hallucis longus tendon is described in this series as an alternative to reconstruct the Achilles tendon in 2 such high-risk individuals. Both patients had a successful outcome with no wound-healing problems and regained acceptable functional status.

Anatomical Study of the Compositions and Internal Connections of the Chiasma Plantare (Master Knot of Henry): Exploring Its Possible Clinical Impact

The purposes of this study were to integrate the types of interconnecting fibers among components of the chiasma plantare and to deduce their flexion actions. The chiasma plantare and the long flexor tendons in 52 cadaveric feet (26 left feet and 25 right feet) were dissected and removed via gross anatomic dissection. The connections among the flexor digitorum longus (FDL), flexor hallucis longus (FHL), and quadratus plantae (QP) were then classified and analyzed. The connection between the FHL and FDL was type I in 43 (86%) cases, type III in 2 (4%) cases, and type V in 5 (10%) cases, with the FHL manipulating the first through third toes and the FDL manipulating the first through the fifth toes. The shape of the QP in 28 (56%) cases exhibited a 2-headed QP, and in 22 (44%) cases, a medial-headed QP. The composition of the chiasma plantare was 2 layers in 28 (56%) cases and 3 layers in 22 (44%) cases: 9 (18%) cases were type a, 2 (4%) cases were type b₁, and 1 (2%) case each was classified as type b₂ and b₃. The FHL controlled the second toe in 10 (20%) cases; both the second and third toes in 27 (54%) cases; and the second, third, and fourth toes in 13 (26%) cases. The QP manipulated the third and fourth toes in all cases, the second toe in 38 (76%) cases, and the fifth toe in 11 (22%) cases. These data suggest that such variations might result from tendon transfer. In conclusion, we considered the FDL to be more advanced for the recovery of both the ankle and the forefoot based on this study.

Strength Measurement After Achilles Tendon Repair

The goal of treatment after Achilles tendon rupture (ATR) is to restore appropriate tension to the tendon, so that normal baseline strength and functional soft-tissue length can be achieved. The assessment of plantarflexion strength has shown widespread variability. The purpose of this study is to document variations in strength assessment after the treatment of ATR in the literature. A comprehensive literature review was performed. In total, 2758 articles were found on Achilles tendon rupture and Achilles tendon strength measurement. The full text of articles including strength as a functional outcome measurement in the abstract were assessed. All objective strength measurements performed were reviewed and recorded for comparison. One-hundred articles were included in our study. In 78 articles, a dynamometer was used to measure strength, whereas in 22 articles, an endurance test (n=14) or formal gait assessment (n=8) was applied. When a dynamometer was used, there was wide variability in the various methods used including the incorporation of both isokinetic (n = 65) and isometric (n = 29) exercises utilizing varying degrees of knee flexion and patient testing position. Furthermore, the number of measurements at certain angular velocities varied. This study illustrates that no general consensus exists regarding an optimal method for measuring strength after ATR. The variability creates difficulty and challenges medical professionals' ability to formulate consistent conclusions when determining functional performance outcomes. A more uniform way of measuring strength after ATR may allow for better comparisons between studies in the literature, potentially leading to a better understanding of strength. Levels of Evidence: Therapeutic, Level II.

Communications between the tendons of flexor hallucis longus and flexor digitorum longus: a cadaveric study

INTRODUCTION

Tibialis posterior tendon insufficiency in adult acquired flat foot deformity (AAFFD) is treated by reinforcing the posterior tibial tendon (PTT) using grafts from flexor hallucis longus (FHL) and flexor digitorum longus (FDL). The communication between FHL and FDL will influence the length of the graft that can be harvested from FHL and FDL. In this study, we aim to study the patterns of communications between FHL and FDL tendons and the location of Master Knot of Henry (MKH) and point of division of FDL tendons in Indian population.

MATERIALS AND METHODS

In this observational descriptive study, 36 formalin-fixed cadavers were sourced from Subbaiah Institute of Medical Sciences, Shimoga, Karnataka, India, and JIPMER, Puducherry, India, during the period of 2017-19. Various parameters of the foot to locate the MKH and point of division of FDL tendons and various types of communications between FHL and FDL were observed.

RESULTS

Among the various types of communications between FHL and FDL tendons, type I was present in 61.76% of cases, type II in 2.94% of cases, type III in 7.35% of cases, type IV in 14.70% of cases, type V in 8.82% of cases, type VI in 0% of cases, type VII in 1.47% of cases and an unusual type in 2.94% of cases.

CONCLUSION

In the present study done in Indian population, we found that type I variety is present more commonly followed by type IV. FHL and FDL tendon grafts can be lengthened based on the communications between them. In type I variety, the communication can be severed at the FDL end to lengthen the tendon graft for harvest.

Endoscopic Management of Chronic Achilles Tendon Rupture

Chronic ruptures of the Achilles tendon are often missed injuries, which is challenging for the surgeon. The complications from reconstruction are a considerable concern. Primary repair may be attempted, but the missed injury often presents later than 4 weeks with gaps greater than 4 cm, necessitating more complex reconstructions using local tissues such as turn-down flaps and VY plasty, requiring large incisions in an unfavorable area of the body. We describe a step-by-step technique of endoscopic flexor hallucis longus reconstruction for chronic Achilles rupture, which decreases local complications. This article reviews the available literature for endoscopic flexor hallucis longus reconstruction.

Flexor Hallucis Longus Transfer Improves Achilles Tendon Load to Failure in Surgery for Non-Insertional Tendinopathy: A Biomechanical Study

BACKGROUND

Non-insertional Achilles tendinopathy is a common disorder that may be treated with surgical debridement. A flexor hallucis longus (FHL) transfer is recommended if debridement of ≥50% is performed; however, there are no biomechanical data to support this. The purpose of this study was to assess the added biomechanical strength provided by an FHL transfer with incrementally sized non-insertional Achilles tendon defects.

METHODS

Thirty matched-pair below-the-knee cadaveric specimens (n = 60) (mean age at the time of donor death, 67 years; range, 36 to 74 years) were obtained and randomly divided into 3 groups according to whether the defect was 25%, 50%, or 75% of the tendon width. One specimen of each pair was then randomly selected to undergo FHL transfer using interference screw fixation. All specimens then underwent cyclic loading of 100 N, and elongation of the medial and lateral limbs of the tendon defect was recorded. The constructs were then loaded to failure to measure stiffness, ultimate strength, and peak elongation before failure.

RESULTS

The specimens with a 75% defect had significantly less elongation of the medial and lateral tendon-defect limbs when an FHL transfer had been done (p < 0.05). Ultimate load to failure was significantly increased in all groups (by 242 to 270 N depending on the defect size) following FHL transfer. Failures usually occurred through the tendon defect in the 75% and 50% defect groups, whereas all failures occurred at the Achilles tendon insertion when a 25% defect had been created. No significant differences were found in peak elongation with the addition of an FHL transfer. FHL augmentation resulted in significantly greater stiffness in the 25% and 75% defect groups (p < 0.05).

CONCLUSIONS

This study showed that an FHL transfer significantly increased load to failure of Achilles tendons with a non-insertional defect involving 25%, 50%, and 75% of the tendon width. The mechanism of failure was usually through the defect in the specimens with a 50% or 75% defect, supporting the use of FHL augmentation with debridement of ≥50%.

CLINICAL RELEVANCE

The present study supports the mechanical concept that FHL transfer is indicated when debridement of the Achilles tendon is ≥50%.

Biomechanical and Morphometric Properties of the Long Flexor Tendons of the Toes: A Cadaver Study

BACKGROUND

We sought to show the biomechanical and morphometric properties of flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendon grafts harvested by specific surgical approaches and to assess the contribution of FHL slips to the long flexor tendons of the toes.

METHODS

Thirteen fresh-frozen amputated feet (average age, 79 years) were dissected. The connections between the FHL and FDL tendons and the contribution of FHL slips to the long flexor tendons were classified. The biomechanical properties of the tendons and slips were measured using a tensile device.

RESULTS

The connections between the FHL and FDL tendons were reviewed in two groups. Group 1 had FHL slips (11 cases) and group 2 had cross-slips (two cases). The FHL slips joined the second and third toe long flexor tendon structures. Tendon length decreased significantly from the second to the fifth toe (P < .001). Apart from the second toe tendon being thicker than that of the fourth toe (P = .02) and Young's modulus being relatively smaller in the third versus the fourth toe tendon (P = .01), biomechanical and morphometric properties of second to fourth tendons were similar. Mechanical properties of those tendons were significantly different from fifth toe tendons and FHL slips. Morphometric and biomechanical properties of FHL slips were similar to those of the fifth toe tendon.

CONCLUSIONS

Herein, FHL slips were shown to have biomechanical properties that might contribute to flexor functions of the toes. During the harvesting of tendon grafts from the FHL by minimally invasive incision techniques from the distal plane of the master knot of Henry, cutting slips between FHL and FDL tendons could be considered a cause of postoperative function loss in toes.

Achilles Tendon Reconstruction With Bone Block Allograft:Long-Term Follow-Up of Two Cases

The treatment of neglected or chronically ruptured Achilles tendon is challenging. Various treatments for large defects associated with chronic Achilles ruptures have been described. Many surgeons recommend the use of a tendon transfer, turndown rotational flap, advancement flap, or reconstruction with Achilles tendon allograft with calcaneal bone block. Long-term outcomes of these procedures are unknown. We present 2 cases with the use of an Achilles tendon with calcaneus bone block allograft. At >8-year follow-up duration, both patients are afforded satisfactory levels of activity and are without pain or gait disturbance. This procedure is a viable option for Achilles ruptures with large defects, ruptures with small intact distal tendon portions, or re-ruptures of previously repaired Achilles tendons. The long-term outcomes of these case reports suggest that Achilles tendon reconstruction with bone block allograft is a viable option.

Outcomes of flexor digitorum longus (FDL) tendon transfer in the treatment of Achilles tendon disorders

BACKGROUND

In patients with chronic Achilles tendon disorders, Achilles tendon debridement can be supplemented with a tendon transfer, with the flexor hallucis longus tendon (FHL) transfer representing the most common used technique. Our study describes clinical and functional results of patients treated with flexor digitorum longus (FDL) tendon transfer in the treatment of patients with chronic Achilles tendon disorders.

METHODS

Retrospective study of prospectively collected data of thirteen patients (15 feet) that underwent FDL tendon transfer as part of the treatment of chronic Achilles tendon disorders. Preoperative and postoperative assessment included visual analogue score (VAS) for pain, SF-36 survey and lower extremity functional scale (LEFS). The average follow-up was 26.4 (range, 14-56) months. Patients were also assessed for ability to perform single leg heel rise test, muscle power for plantar flexion of the lesser toes, surgical scar condition and associated complications.

RESULTS

At final follow-up, we found significant postoperative improvement in VAS score (6.6 ± 2.99 vs 1.06 ± 1.43; p < .0001), SF-36 physical component summary (PCS) (28.20 ± 10.71 vs 45.04 ± 11.19; p < .0001) and LEFS (36.13 ± 20.49 vs 58.73 ± 18.19; p < .0001). Twelve patients (92%) could perform a single leg heel rise test in the operated extremity, although there was significant difference when comparing operated and uninvolved sides (4.86 ± 3.36 cm vs 7.18 ± 3.40 cm; p = .0002). One patient reported weakness for plantar flexion of the lesser toes, without balance or gait disturbances. Two patients (2 feet, 13.3%) had superficial infections and one patient (one foot, 6.6%) needed operative debridement for a deep infection.

CONCLUSIONS

FDL tendon transfer represent an operative alternative in the treatment of chronic Achilles tendon disorders. Our study showed good clinical outcomes with low complications and donor site morbidity.

LEVEL OF EVIDENCE

Observational study, case series - level IV.

Focal adhesion kinase coordinates costamere-related JNK signaling with muscle fiber transformation after Achilles tenotomy and tendon reconstruction

Achilles tendon rupture necessitates rapid tendon reattachment to reinstate plantar flexion before affected muscles deteriorate through muscle fiber atrophy and transformation. The implicated process may involve alterations in sarcolemmal sites of myofibril attachment (costameres), which control myofibrillogenesis via a mechano-regulated mechanism through integrin-associated focal adhesion kinase (FAK). We assessed the contribution of FAK to alterations in fiber type composition and expression of costamere-associated structural proteins, the phosphorylation status of Y397-FAK and downstream mTOR/JNK-P70S6K hypertrophy signaling in rat soleus muscle after Achilles tenotomy and tendon repair. Achilles tenotomy induced a profound deterioration of muscle composition 14 days, but not 4 days, following tendon release, comprising specifically increased area percentages of fast type fibers, fibers with internal nuclei, and connective tissue. Concomitantly, expression of costameric proteins FAK and meta-vinculin, and phosphorylation of T421/S424-P70S6K and T183/Y185-JNK was elevated, all of which was mitigated by tendon reattachment immediately after release. Overexpression of FAK in soleus muscle fibers and reattachment corrected the expression of meta- and gamma-vinculin isoforms to the lower levels in mock controls while further enhancing T183/Y185-JNK phosphorylation and levels of FAK C-terminus-related inhibitory proteins. Co-overexpression of the FAK inhibitor, FRNK, lowered FAK-overexpression driven Y397-FAK phosphorylation and T183/Y185-JNK phosphorylation. FAK levels correlated to molecular and cellular hallmarks of fiber degeneration. The findings demarcate the window between 4 and 14 days after tenotomy as costamere-dependent muscle transformation process, and expose that FAK overexpression prevents molecular aspects of the pathology which within the study limitations does not result in the mitigation of muscle fiber degeneration.250 words.

Plantarflexor fiber and tendon slack length are strong determinates of simulated single-leg heel raise height

Achilles tendon ruptures have been linked with detrimental changes in muscle-tendon structure, which may help explain long-term functional deficits. However, the causal effects of muscle-tendon structure on joint function have not been tested in a controlled setting. Therefore, the purpose of this study was to test the implications of muscle-tendon unit parameters on simulated single-leg heel raise height. We hypothesized that muscle fiber length and resting ankle angle - a clinical surrogate measure of tendon slack length - would predict single-leg heel raise height more strongly than other parameters. To test this hypothesis, we developed a two-part simulation paradigm that recreated clinically relevant muscle-tendon scenarios and then tested these parameters on single-leg heel raise height. We found that longer muscle fibers had the greatest positive effect on single-leg heel raise height. However, tendon slack length, determined by simulating resting ankle angles in a secondary analysis, revealed a stronger negative correlation with heel raise height. Our findings support previous clinical observations that both muscle fascicle length and resting tendon length are important muscle-tendon parameters for patient function. In addition to minimizing tendon elongation following rupture, treatment plans should focus on preserving plantarflexor muscle structure to mitigate functional loses following Achilles tendon ruptures.

Anatomic Basis for Minimally Invasive Flexor Hallucis Longus Transfer in Chronic Achilles Tendon Rupture

The present cadaveric study was designed to measure the flexor hallucis longus (FHL) tendon length and obtain anatomic data regarding the graft-to-tunnel length ratio in an interference screw fixation model for the FHL short-harvest single-incision technique to the calcaneus. Ten fresh-frozen paired cadaveric specimens were used for the FHL short-harvest technique. The length of the osseous tunnel in the calcaneus was measured. At harvesting of the FHL tendon, the length of the tendon that traverses the osseous tunnel was measured with the ankle in neutral and maximal plantarflexion from the tip of the osseous tunnel to the transected end of the tendon within the bone tunnel. The mean length of the osseous tunnel was 42.7 ± 2.3 (range 38 to 46) mm. With the ankle in neutral position, the mean length of the FHL tendon traversing the bone tunnel was 31 ± 1.7 (range 29 to 34) mm. This mean length increased to 38.8 ± 1.6 (range 36 to 41) mm with the ankle placed in maximal plantarflexion. The ratio of the mean length of the tendon graft to the mean length of the osseous tunnel with the ankle in neutral was 0.727 ± 0.046 (range 0.667 to 0.81), and the ratio was 0.91 ± 0.042 (range 0.864 to 0.976) when the ankle was maximally plantarflexed. To the best of our knowledge, we report for the first time that the short-harvest technique provides >70% (ratio 0.727) of the FHL tendon graft in the osseous tunnel at all times, even when then ankle is in neutral, resulting in sufficient tendon length for FHL tendon transfer to the calcaneus for chronic Achilles tendon rupture.

Endoscopic Transfer of Flexor Hallucis Longus Tendon for Chronic Achilles Tendon Rupture: Technical Aspects and Short-Time Experiences

BACKGROUND

Chronic Achilles tendon ruptures can lead to reduced power of plantar flexion in the ankle with impaired gait ability. The open 1- or 2-incision technique for flexor hallucis longus transfer has proven good functional outcome but has the disadvantage of relatively extensive surgery performed at a vulnerable location. To reduce the risk of soft tissue problems, the flexor hallucis longus transfer can be performed endoscopically.

MATERIAL AND METHOD

An endoscopic technique for flexor hallucis longus transfer is presented together with the experiences from the first six patients operated with this method.

RESULTS

No wound healing problems or infections. Five of 6 patients managed single leg heel raise on the affected side 12 months after surgery.

CONCLUSION

The functional results are promising. The soft tissue dissection is minor, and no patients had postoperative wound healing problems or infection. Endoscopic flexor hallucis longus transfer may be an operative procedure that can be considered also in patients with potential wound healing problems.

LEVELS OF EVIDENCE

Level IV: Technical note/case series without controls.

Postoperative Imaging of the Ankle

OBJECTIVE

The purpose of this article is to review imaging after commonly encountered surgical interventions of the ligaments, tendons, and soft tissues around the ankle. Intraoperative images, when available, are provided to improve conceptual understanding of these complex procedures.

CONCLUSION

Surgical interventions in the ankle are becoming more prevalent with increasing athletic demands and emerging focus on techniques for prevention of joint injury. Knowledge of the surgical techniques, imaging appearances, and complications in the postoperative ankle is necessary for the accurate diagnosis of postoperative complications and for optimal patient care.

The functional and dynamometer-tested results of transtendinous flexor hallucis longus transfer for neglected ruptures of the Achilles tendon at six years' follow-up

Aims

Flexor hallucis longus (FHL) tendon transfer is a well-recognized technique in the treatment of the neglected tendo Achillis (TA) rupture.

Patients and Methods

We report a retrospective review of 20/32 patients who had undergone transtendinous FHL transfer between 2003 and 2011 for chronic TA rupture. Their mean age at the time of surgery was 53 years (22 to 83). The mean time from rupture to surgery was seven months (1 to 36). The mean postoperative follow-up was 73 months (29 to 120). Six patients experienced postoperative wound complications.

Results

The mean postoperative Achilles tendon Total Rupture Score (ATRS) was 83 (40 to 100) and the mean American Orthopaedic Foot & Ankle Society (AOFAS) score was 94.3 (82 to 100). Tegner scoring showed a mean reduction of one level from the pre-injury level of activity. There was a mean reduction of 24% (4 to 54) in dynamometer-measured strength of ankle plantarflexion, in comparison with the non-operated side. The hallux had a mean of only 40% (2 to 90) strength of plantarflexion in comparison with the contralateral side.

Conclusion

We conclude that transtendinous FHL transfer for neglected TA ruptures, with a long harvest to allow reattachment of the triceps surae, provides reliable long-term function and good ankle plantarflexion strength. Despite the loss of strength in hallux plantar flexion, there is little comorbidity from the FHL harvest. Cite this article: Bone Joint J 2018;100-B:584-9.

Anatomical feasibility study of flexor hallucis longus transfer in treatment of Achilles tendon and posteromedial portal of ankle arthroscopy

PURPOSE

The aim of this study was to evaluate the occurrence of anatomical variations of the musculotendinous junction of the flexor hallucis longus (FHL) muscle, the relationship between FHL tendon or muscle and the tibial neurovascular bundle at the level of the posterior ankle joint in human cadavers.

METHODS

Seventy embalmed feet from 20 male and 15 female cadavers, the cadavers' mean age was 65.4 (range from 14 to 82) years, were dissected and anatomically classified to observe FHL muscle morphology define the relationship between FHL tendon or muscle and the tibial neurovascular bundle. The distance between the musculotendinous junction and the relationship between FHL tendon or muscle and the tibial neurovascular bundle was determined.

RESULTS

Three morphology types of FHL muscle were identified: a long lateral and shorter medial muscle belly, which was observed in 63 specimens (90%); equal length medial and lateral muscle bellies, this variant was only observed in five specimens (7.1%); one lateral and no medial muscle belly, which was observed in two specimens (2.9%). No statistically significant difference was observed according to gender or side (p > 0.05). Two patterns were identified and described between FHL tendon or muscle and the tibial neurovascular bundle. Pattern 1, the distance between the neurovascular bundle and FHL tendon was 3.46 mm (range 2.34-8.84, SD = 2.12) which was observed in 66 specimens (94.3%); Pattern 2, there was no distance which was observed in four specimens (5.7%).

CONCLUSION

Knowing FHL muscle morphology, variations provide new important insights into secure planning and execution of a FHL transfer for Achilles tendon defect as well as for the interpretation of ultrasound and magnetic resonance images. With posterior arthroscopic for the treatment of various ankle pathologies, posteromedial portal may be introduced into the posterior aspect of the ankle without gross injury to the tibial neurovascular structures because of the gap between the neurovascular bundle and FHL tendon.