Zigzag tenotomy of the extensor hallucis longus through minimally invasive surgery in cadaveric specimens: description of a new technique.

BACKGROUND: Lengthening of the extensor hallucis longus (EHL) is performed to address various forefoot pathologies. The retraction of this tendon is strongly associated with the Hallux Abductus Valgus (HAV) deformity. Minimally Invasive Surgery (MIS) lengthening of the EHL is carried out in combination with other surgical techniques for HAV bone realignment. It is performed without ischemia, using local anesthesia and sedation if required by the patient. One of the advantages of this technique is immediate ambulation with a postoperative shoe without the need for a cast. The objective of the research was to demonstrate the efficacy and safety of the minimally invasive technique for lengthening the tendon in patients with HAV. MATERIALS AND METHODS: The procedures were performed on 11 fresh cryopreserved cadaveric feet. HAV surgery was performed through dorsomedial and dorsolateral portals for Reverdin-Isham, Akin and adductor tenotomy. In addition, EHL tendon elongation was performed using the Beaver 67 MIS scalpel through an incomplete zigzag tenotomy. The specimens used did not present any type of disease nor had they undergone previous surgeries that could affect the technique. First, the plantar flexion of the metatarsophalangeal joint was measured with a goniometer to establish the degrees of this joint before proceeding with the technique, the tenotomy was performed and remeasured and finally the osteotomy was performed. In addition, an anatomical dissection of cadaveric specimens was performed and various anatomical and surgical relationships were analyzed and measured. RESULTS: The data indicate that, after performing zigzag tenotomy, there is an average improvement of 13.91 degrees in plantar flexion. CONCLUSIONS: The study confirms the effectiveness and safety of elongating the extensor hallucis longus tendon of the hallux using minimally invasive surgery. The zigzag technique for tendon elongation may be considered a viable minimally invasive treatment option for addressing tendon hyperextension in patients with HAV.

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

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

A Neglected Extensor Hallucis Longus Tendon Rupture Caused by Arthritic Adhesion.

Extensor hallucis longus tendon injury is relatively rare and is principally caused by a laceration when a sharp object is dropped on the instep. Primary suturing is possible if the injury is acute, but if the tear is chronic, tendon contracture causes the space between the edges of the tear to widen, disrupting the end-to-end connection. In particular, a claw toe or checkrein foot deformity may develop over time due to adhesion of the lower leg tendons near the fracture site or scar. We report on a 44-year-old man who visited our outpatient clinic complaining of pain in the right foot and a hindered ability to extend his great toe. He had enjoyed playing soccer during his schooldays; since that time, the extension of that toe had become somewhat difficult. T2-weighted sagittal magnetic resonance imaging revealed that the continuity of the extensor hallucis longus tendon had been lost at the distal phalangeal base attachment site, and that the region of the proximal tendon was retracted to level of the middle shaft of the proximal phalanx. The findings allowed us to diagnose extensor hallucis longus tendon rupture accompanying osteoarthritic changes in the joint and soft tissues. We performed surgical tenorrhaphy and adhesiolysis. This is a rare case of extensor hallucis longus tendon rupture caused by minor trauma. Arthritis that developed at a young age caused the adhesions. If patients with foot and ankle arthritis show tendon adhesion at the arthritic site, tendon rupture can develop even after minor trauma or intense stretching.

Coexistence of accessory band with the second type of extensor hallucis longus.

The main muscles responsible for extension of the toes are the extensor digitorum longus and extensor hallucis longus. Morphological variants of both of these muscles are mostly related to the numbers of tendons and their unusual points of insertion. The case presented shows an accessory band deriving from the extensor digitorum longus and fusing with the extensor hallucis longus, a concomitant additional tendon of the latter inserting to the proximal phalanx of the hallux. Knowledge of these anatomical patterns is important not only from the anatomical but also the clinical point of view and can be useful in lower limb surgery.

Characteristics of the accessory tendon of the extensor hallucis longus muscle: a Taiwanese study.

PURPOSE: The main tendon of the extensor hallucis longus (EHL) muscle attaches to the dorsal aspect of the distal phalanx of the great toe. One or multiple accessory tendons of the EHL have been reported in several ethnic/regional groups, except Taiwan. This study aimed to investigate the incidence, length, and insertion of the accessory tendon of the EHL in Taiwanese people. METHODS: Anatomical dissection was performed on 48 feet of 24 formalin-embalmed cadavers. The occurrence and morphological characteristics of the accessory tendon of the EHL were recorded and analyzed. RESULTS: The accessory tendon of the EHL was found in 97.92% (47/48) of the legs that were dissected. In one male cadaver, an independent muscle belly was identified in each leg, whereas all the other accessory tendons originated from the main tendon of the EHL. In this study, the insertion of the accessory tendon were classified into four patterns. The most common insertion sites were the first metatarsophalangeal (MTP) joint capsule and proximal phalanx of the great toe. The length of the accessory tendons did not correlate with age or with sex when the two tendons with independent muscle belly were excluded. CONCLUSIONS: The accessory tendon of the EHL appears to be a regular feature in Taiwanese people. Most accessory tendons of the EHL (85.7%) attached on the first MTP joint capsule may play a role in the prevention of capsular impingement during great toe extension.

Independent muscle of extensor hallucis capsularis: a cadaveric case report.

Extensor hallucis capsularis (EHC) is an accessory tendon located medially to extensor halluces longus (EHL) tendon. Most EHC is known to originate as a tendinous slip of the EHL tendon, although it may be splitted from the tibialis anterior (TA) tendon or the extensor halluces brevis (EHB) tendon. During routine dissection of a 49-year-old male cadaver, independent muscle bellies of EHC were discovered bilaterally. The EHL muscle arose from the middle anteromedial aspect of fibula, lateral to the origin of TA muscle and medial to extensor digitorum longus (EDL) muscle. An additional muscle bellies were separated from EHL muscle at the point of 6 cm away from EHL origin in the right leg, and 3 cm away in the left. They coursed downward as EHC to reach the first metatarsophalangeal joint capsule. This muscle, unlike the variations identified to date, is considered to extend to EHC, and the name "extensor hallucis capsularis muscle" is offered. This kind of variation may be important for investigating the development of deformity at the first metatarsophalangeal joint, such as hallux valgus.

A Combined Surgical Approach for Extensor Hallucis Longus Reconstruction: Two Case Reports.

The surgical management of foot tendon injuries is not well-represented in literature. To achieve excellent functional recovery of the extensor hallucis longus (EHL) tendon, we aimed at developing a reliable and feasible reconstructive technique. A surgical technique for delayed reconstruction of the EHL tendon, combining an elongation procedure with second toe extensor tendon transfer, is described in this article. The results of this combined approach for EHL tendon reconstruction were remarkable, since the patients of the two clinical cases reported regained active extension of the hallux after 6 months without any associated complication. This study represents a step forward in foot surgery, since it describes an alternative technique to manage EHL tendon lesions.

Is ultrasound effective in determining variation of the insertion of the extensor hallucis longus tendon?

BACKGROUND: The extensor hallucis longus (EHL) is located in the anterior compartment of the leg, between the tibialis anterior muscle and extensor digitorum longus. The EHL is characterized by a number of morphological variations, concerning mainly the accessory bands and their insertion. The aim of our research was to evaluate the effectiveness of ultrasound in determining the anatomical variations of the EHL. METHODS: The morphology of the EHL was evaluated by ultrasound (high-frequency linear probe of Samsung RS80 apparatus) in 50 healthy volunteers. The types of EHL morphology were determined according to a threefold classification. RESULTS: Only two types of the threefold anatomical classification were observed: Type I in 76 limbs (76%) and Type IIa in 24 limbs (24%). The accessory bands of the EHL were found in 24% of cases, all of which demonstrated a course that was located medially in relation to the main tendon. CONCLUSION: Ultrasound allows for visualization of the EHL; however, the potential recognition of morphological variance is limited. LEVEL OF EVIDENCE: I - Clinical Research.

Optimal needle placement for extensor hallucis longus muscle using ultrasound verification.

INTRODUCTION: The extensor hallucis longus (EHL) muscle is important for diagnosis of neurologic lesions. It is also a target muscle for treatment. We investigated EHL with ultrasonography to determine optimal needle placement for safety and accuracy. METHODS: A total of 96 legs of 48 healthy volunteers were examined through ultrasonography. Four published electromyographic methods for finding the EHL were assessed. We identified the midpoint of EHL (MD) using landmarks to determine optimal needle placement. RESULTS: Mean values of bimalleolar line-MD on skin (MD-S) and tibial crest-MD-S were 10.5 ± 1.2 cm and 3.6 ± 0.4 cm, respectively. The depth of MD was 1.6 ± 0.2 cm. According to 4 EMG methods, the probability of needle penetrating EHL was 13% to 79% and that of needle penetrating the neurovascular bundle was 50% to 89%. CONCLUSIONS: Using ultrasonography, we could determine optimal needle placement in the EHL. Muscle Nerve 59:331-336, 2019.

A cadaveric study of the morphology of the extensor hallucis longus - a proposal for a new classification.

BACKGROUND: Morphological variations of the EHL concern mainly the accessory tendons and the site of their insertion. The aim of our study is to present a new classification of the EHL. METHODS: Classical anatomical dissection was performed on 104 lower limbs (51 right, 53 left, fixed in 10% formalin solution). RESULTS: In the cadavers, three types of morphology (insertion and addidtional band) were observed. Type I, the most common type, was characterized by a single tendon that ends as an extensor hood on the dorsal aspect of the base of the distal phalanx of the big toe (57.7%). Type II was characterized by two distal tendons and was subdivided into three subtypes according to (A-29.9%, B-4.8% and C-5.7%). Type III was characterised by three distal tendons (two cases - 1.9%). CONCLUSION: The EHL presents high morphological variability. Knowledge of particular types of insertion is essential for both clinicians and anatomists.

Local Autograft and Strong Pulvertaft Fixation Technique for Reconstruction of a Rerupture of the Extensor Hallucis Longus Tendon: A Case Report.

There are different treatment options for extensor hallucis longus injuries. For primary repair, the end-to-end suture is recommended. The treatment of reruptures or tendon defects is challenging, and a wide range of procedures have been used in this regard, including primary and secondary repairs with and without auto- and allografts. To overcome the disadvantages of second-site morbidity and to achieve high primary stability, we demonstrate a technique using a local tendon graft in combination with a strong Pulvertaft suture technique in a case of rerupture of the extensor hallucis longus tendon.

Technique tip: EDL-to-EHL double loop transfer for extensor hallucis longus reconstruction.

BACKGROUND: Extensor hallucis longus (EHL) tendon injuries often occur in the setting of lacerations to the dorsum of the foot. End-to-end repair is advocated in acute lacerations, or in chronic cases when the tendon edges are suitable for tension free repair. Reconstruction with allograft or autograft is advocated for cases not amenable to a primary direct repair. This is often seen in cases with tendon retraction and more commonly in the chronic setting. In many countries the use of allograft is very limited or unavailable making reconstruction with autograft and tendon transfers the primary choice of treatment. Tendon diameter mismatch and diminished resistance are common issues in other previously described tendon transfers. METHODS: We present the results of a new technique for reconstruction of non-reparable EHL lacerations in three patients using a dynamic double loop transfer of the extensor digitorum longus (EDL) of the second toe that addresses these issues. RESULTS: At one-year follow up, all patients recovered active/passive hallux extension with good functional (AOFAS Score) and satisfaction results. No reruptures or other complications were reported in this group of patients. No second toe deformities or dysfunction were reported. CONCLUSIONS: Second EDL-to-EHL Double Loop Transfer for Extensor Hallucis Longus reconstruction is a safe, reproducible and low-cost technique to address EHL ruptures when primary repair is not possible. LEVEL OF EVIDENCE: IV (Case Series).

Split Peroneus Longus Free Tendon Autograft Transplantation for the Treatment of Neglected Extensor Hallucis Longus Tendon Laceration: A Case Report.

A neglected laceration of the extensor hallucis longus (EHL) tendon is rare. Retraction of the tendon ends often occurs when a laceration is neglected, leading to a substantial tendon deficit. A paucity of case reports is available describing the treatment of EHL laceration with a large area of gap secondary to retraction. Therefore, the treatment recommendations are limited. We present the case of a neglected EHL tendon laceration with a 10.5-cm gap in a healthy 22-year-old female. The EHL tendon laceration was repaired using a split peroneus longus tendon autograft that, to the best of our knowledge, has not been previously reported. At the 3-year follow-up evaluation, the patient retained full function of her hallux and was free of symptoms.

Obtaining Adequate Tension for Extensor Hallucis Longus Tendon Rupture Repair Using Wide-Awake Surgery: A Case Report.

Wide-awake surgery has potential advantages for treating extensor or flexor tendon injury. We present a case of chronic extensor hallucis longus injury treated with turn-down reconstruction using wide-awake surgery with a selective nerve block. To the best of our knowledge, this is the first such case reported. The patient had dropped a knife proximal to the right hallux metatarsophalangeal joint. Because direct suturing was thought to be difficult, turn-down reconstruction was performed under a selective nerve block. At 8 months postoperatively, the hallux had 75° of extension in the metatarsophalangeal joint and -5° of extension in the interphalangeal joint, similar to those of the healthy foot. The Japanese Society for Surgery of the foot objective hallux scale score had improved from 87 to 100, and the subjective scores in the subcategories of pain and pain-related, physical functioning and daily living, and shoe-related in the self-administered foot evaluation questionnaire had improved from 82.8 to 94.4, 97.7 to 100, and 50 to 83.3, respectively. Turn-down reconstruction using wide-awake surgery with a selective nerve block can be used for chronic extensor hallucis longus rupture and can be expected to provide good results.

A Review of Extensor Hallucis Longus Variants Featuring a Novel Extensor Primi Internodii Hallucis Muscle Merging With Extensor Hallucis Brevis.

The extensor hallucis longus (EHL) muscle/tendon complex has been used in a variety of tendon transfer and tenodesis surgeries to correct iatrogenic hallux varus deformity, equinovarus foot deformity, clawed hallux associated with a cavus foot, and dynamic hyperextension of the hallux and, even, to prevent pedal imbalance after transmetatarsal amputation. Although it is usually considered a unipennate muscle inserting into the dorsum of the base of the distal phalanx of the hallux, a vast majority of EHL muscles possess ≥1 accessory tendinous slips that insert into other neighboring bones, muscles, or tendons, which can complicate these surgeries. The present report reviewed the reported data on EHL variants and describe a new variant, in which the tendons of the extensor primi internodii hallucis muscle of Wood and extensor hallucis brevis muscle merged together proximal to the tarsometatarsal (Lisfranc) joint, a site of rupture for extensor tendons of the foot. The reported variant might have contributed to the development of the clawed hallux seen in our patient and could complicate its operative management by mimicking the normal extensor digitorum longus tendon. Knowledge of the EHL variants and the particular muscular pattern described in the present review could improve the diagnosis and tendon transfer and tenodesis operative planning and outcomes.

The accessory tendon of extensor hallucis longus muscle and its correlation to hallux valgus deformity: a cadaveric study.

PURPOSE: The accessory tendon (AT) of the extensor hallucis longus (EHL) is a common anatomic variation, whose clinical significance remains debatable. The purpose of this study was to investigate the incidence and morphology of accessory EHL tendons in cadavers and to examine any possible correlation to the occurrence and severity of hallux valgus (HV) deformity. METHODS: We examined any possible correlation between the AT presence and the cadavers' age and the HV deformity in 98 female adult cadaveric feet. The HV and intermetatarsal (IMA) angles were measured and compared with the relative angle between the primary EHL tendon and AT as well as the length of the AT. RESULTS: AT was present in 26.5% and HV deformity existed in 36.7% of all feet. There was a high prevalence (65.4%) of HV deformity in feet with AT, but the HV angle and IMA were similar in feet with AT and without AT. No significant correlations were found between AT morphological characteristics and the cadavers' age or the HV angle and IMA. CONCLUSIONS: In conclusion, there is a high incidence of HV deformity in cadaveric feet with AT of EHL (almost 2/3), but there is no correlation between the severity of the HV deformity and the presence or characteristics of the AT.

Review of Drop Hallux: Assessment and Surgical Repair.

Peroneal nerve palsy is common. The hallmark clinical manifestation of peroneal nerve palsy is drop foot. In the drop foot condition, the ankle cannot flex, and the foot does not clear the ground during the swing phase of gait. Spontaneous nerve repair can yield complete or incomplete resolution of drop foot. Some patients with incomplete resolution are left with a drop hallux condition, in which the ankle can dorsiflex, but the hallux remains unable to dorsiflex. This has not been thoroughly discussed in the past, regarding surgical repair. In the present report, we have reviewed the drop hallux condition and an effective surgical repair option (extensor hallucis longus to tibialis anterior tendon anastomosis). Our case report presents a healthy 27-year-old male who had persistent drop hallux after drop foot resolution, 3 years after external fixation of a closed, proximal tibia-fibula fracture.

The extensor hallucis capsularis tendon--a prospective study of its occurrence and function.

BACKGROUND: There is inhomogeneous data about the hallucal extensor apparatus and the occurrence of accessory tendon slips and their function. We performed this study to clarify its anatomical features and make conclusions about its function. METHODS: Investigations were performed prospectively during operative correction of severe hallux valgus and interphalangeus in 60 consecutive cases. The occurrence, topographic location and size of accessory extensor tendons as well as the insertion patterns were recorded. After dissection traction of the accessory tendon was carried out to gain information about its function. RESULTS: In contradiction to previous studies reporting numerous variations in the distal attachments of the hallucal extensor apparatus with different accessory tendons described, our investigations showed constant anatomical features. In all but one case (98.3%) there was an accessory medial extensor hallucis longus tendon adjacent to the main tendon, always inserting on the dorsomedial aspect of the metatarsophalangeal joint capsule. We therefore chose the terminology extensor hallucis capsularis (EHC) used in previous studies. The intraoperative testing of the tendon showed it to exert a pretension of the metatarsophalangeal (MTP) joint capsule. CONCLUSION: Our study showed consistent anatomical features with an occurrence of the EHC tendon in 98.3%. We determined that its function is to pretension the MTP joint capsule, therefore avoiding capsular impingement during hallucal extension. The high incidence of the EHC tendon in our study may also postulate a correlation with MTP joint deformities and further cadaveric studies will be necessary to evaluate a possible predisposition for hallux valgus genesis.

Checkrein deformity due to extensor hallucis longus hypotrophy treated with extensor digitorum longus tendon transfer.

Checkrein deformity is a relatively rare condition caused by hypotrophy or adhesion of a tendon after a lower leg injury. The occurrence of this condition due to the dysfunction of the extensor hallucis longus (EHL) is extremely rare. Only a few related case reports have been published, and Z-lengthening of the EHL tendon was performed for almost all patients. We report a case of checkrein deformity due to EHL hypotrophy. The patient was involved in a traffic accident 7 years ago. He sustained left tibial and fibular closed diaphyseal fractures and underwent minimally invasive plate osteosynthesis. He continued to have left great toe symptoms characterized by dorsiflexion of the great toe during ankle plantarflexion. The EHL had become an insufficient power source because of considerable hypotrophy. Therefore, a tendon transfer using the extensor digitorum longus to the second toe was performed as a primary treatment.

Unravelling the Anatomy of the Anterior Tarsal Tunnel and Its Clinical Implications.

BACKGROUND: Anterior tarsal tunnel (ATT) syndrome is caused by the compression of the deep fibular nerve (DFN) within the ATT beneath the inferior extensor retinaculum, bounded by the tendons of the extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Compression may result from direct trauma, repetitive mechanical irritation, and thrombosis of the dorsalis pedis artery. Injury to the contents of ATT could occur during ankle arthroscopy. Therefore, this study was undertaken to provide a detailed description of the anatomy of the ATT and its clinical implications. MATERIALS AND METHODS: Ten formalin-fixed cadavers were utilized for the study. The ATT was identified between the tendons of the EHL and EDL. The length at the medial and lateral boundaries and the width at the proximal end, middle, and distal end of the ATT were measured using a digital Vernier calliper. RESULT: The mean length of the medial border of the tunnel was 31.42±8.44 mm, while the lateral border was 20.39±4.39 mm. The width of the ATT increased from the proximal to the distal end. DFN was related to the DPA laterally in 15 limbs and medially in five limbs within the tunnel. CONCLUSION: The present study not only describes the intricate anatomy of the ATT but also describes the patterns of DFN and DPA within the tunnel. Understanding the anatomy of ATT is crucial, as it paves the way for safe and efficient surgical interventions, thereby significantly reducing the risk of neurovascular damage during surgical procedures.