Extensor Digitorum Longus Tendon Research Articles

Revisiting the anatomy of inferior extensor retinaculum of foot and ankle, a study based on fifty embalmed adult cadaveric lower extremities

BackgroundThe facial condensation of deep fascia form retinacula, Superior and Inferior, with a primary function to hold the extensor tendons of the foot in position. The morphology of inferior extensor retinaculum (IER) is clinically important in the tendon rupture repair and foot drop surgeries. The anatomy of ankle and foot IER is not much investigated and this prompted us to conceptualize this study to investigate the morphology and morphological variants of IER. MethodsThis descriptive, cross-sectional institutional based study included 50 dorsa of feet from the 25 embalmed adult cadavers. ResultsThe present study observed that, the anatomy of IER is complex wherein multiple septa of varied thickness arise from its undersurface from both the stem and limbs, defining its compartments. Five well defined compartments existed, which lodged the extensor tendons. The third compartment was deep and overlapped by the extensor digitorum longus tendons. Fourth compartment was well defined and lodged the extensor digitorum longus and peroneus tertius tendons, separated by an ill-defined septum. However, in 6 specimens (12%), the peroneus tertius traversed the fifth compartment, which otherwise did not have any contents. Some morphological variants of the tendons were also noted as they passed beneath the IER. ConclusionOur study is novel in determining the compartment format, deeper connections of IER, and relations with deeper structures along with the anatomical variations, which are clinically important in ankle arthroscopy, tendinoscopy, tendon repairs and foot drop stabilization surgeries.

Validation of anterior ankle soft tissue dynamics and shear modulus for anterior ankle impingement syndrome after ankle fracture surgery

Anterior ankle impingement syndrome (AAIS) has been reported to account for a high percentage of complications following ankle fracture surgery. The soft tissue etiology of AAIS is thought to be thickening and inflammation of the anterior ankle soft tissues intervening anteriorly at the tibiotalar joint, causing pain and functional limitation during dorsiflexion. However, the effects of anterior ankle soft tissue dynamics and stiffness on AAIS have yet to be clarified. This study aimed to determine the relationship between AAIS and the anterior ankle soft tissue thickness change ratio and shear modulus using ultrasonography (US). The participants were 20 patients with ankle joint fractures (AO classification A, B) who had undergone open reduction and internal fixation and 20 healthy adults. The evaluation periods were 3 months and 6 months postoperatively. US was used to delineate the tibialis anterior tendon, extensor hallucis longus tendon, and the extensor digitorum longus tendon over the talus and tibia on a long-axis image. Anterior ankle soft tissue thickness was measured as the shortest distance from the most convex part of the talus to the tendon directly above it. The Anterior ankle soft tissue thickness change ratio was determined by dividing the value at 0° dorsiflexion by the value at 10° plantarflexion. The same images as for the anterior soft tissue thickness measurement were drawn for the shear modulus measurement, and the average shear modulus (kPa) was calculated using shear-wave elastography. There was no significant difference in the thickness change ratio between the postoperative and healthy groups. Compared with the healthy group, the shear modulus was significantly higher at 3 and 6 months in the postoperative group (p < 0.01). The shear elastic modulus at 6-month postoperative group was significantly lower than at 3-month postoperative group (p < 0.01). Anterior ankle joint soft tissue stiffness may increase after surgery for an ankle fracture.

Reconstruction of the Anterior Tibialis Tendon Using In-phase Tendon Transfers

Anterior tibialis tendon ruptures or lacerations are rare conditions that do not have a universally accepted treatment. Previously reported methods have described end-to-end repair, transfer of the extensor hallucis longus, and allograft interposition graft. The purpose of this paper is to describe a technique for reconstruction of the anterior tibialis tendon with a transfer of the medial 2 tendons of the extensor digitorum longus (EDL) to span any gaps or diseased tendon. In addition, the lateral 2 tendons of the EDL are transferred to the peroneus tertius to balance dorsiflexion and prevent overpull on the fourth and fifth toes if the EDL tendons are left in place. Using the EDL to reconstruct the anterior tibialis provides an in-phase tendon transfer resulting in symmetric dorsiflexion at the ankle. In addition, the EDL is a normal muscle with the capacity for hypertrophy, which supplements the muscle power of the injured anterior tibialis which often atrophies in the interim between injury and repair. Level of Evidence: Diagnostic Level V. See Instructions for Authors for a complete description of levels of evidence.

Minimally invasive subtalar joint and talonavicular joint preparation for hindfoot arthrodesis: A Cadaveric study evaluating structures at risk

Minimally invasive surgery (MIS) is growing in popularity due to smaller incisions, faster recovery times with less post-operative pain, and measurable decreases in morbidity. Our center performed an MIS hindfoot joint preparation about the talonavicular and subtalar joints and defined structures at risk in order to make this procedure more reproducible. Using ten fresh frozen cadaver limbs, we created a medial and lateral portal for talonavicular joint (TN) access, and an additional portal for subtalar joint (STJ) access to prepare the subtalar joint. After denuding the aforementioned joints of cartilage, the specimens were dissected to identify nearby anatomical structures. We documented the position of the peroneal sheath and sural nerve relative to the STJ portal, and the position of the dorsalis pedis artery (DP), medial dorsal cutaneous nerve (MDCN), extensor hallucis longus (EHL), extensor digitorum longus (EDL), tibialis anterior (TA), and tibialis posterior (TP) tendons relative to the TN portals. The average distance of the sural nerve and the peroneal sheath from the STJ portal was 34.21 mm and 14.12 mm respectively. The average distance of the DP, MDCN, and deep peroneal nerve from the medial and lateral TN portals were 13.31 mm, 11.54 mm, and 17.14 respectively. No neurovascular structures were transected throughout joint preparation. To our knowledge this is the first study looking into structures at risk for this specific procedure.

Anatomical landmarks for ankle block

We aimed to describe anatomical landmarks to accurately locate the five nerves that are infiltrated to accomplish anaesthesia of the foot in an ankle block. Twenty-four formaldehyde-fixed cadaveric ankles were studied. Photographs of cross sections of the frozen legs, cut at a horizontal plane across the most prominent points of the medial and lateral malleoli, were analysed. The curvilinear distance from the most prominent point of the closest malleolus to each of the five cutaneous nerves and their depth from the skin surface were measured. Sural, tibial, deep peroneal, saphenous and medial dorsal cutaneous nerves were located 5.2 ± 1.3, 9.2 ± 2.4, 7.4 ± 1.9, 2.8 ± 1.1, 2.1 ± 0.6 mm deep to the skin surface. The curvilinear distances from the medial malleolus to the tibial, deep peroneal and saphenous nerves were 32.5 ± 8.9, 62.8 ± 11.1 and 24.4 ± 7.9 mm, respectively. The curvilinear distances from the lateral malleolus to the sural and medial dorsal cutaneous branches of superficial peroneal nerves were 27.9 ± 6.3 and 52.7 ± 7.3 mm, respectively. The deep peroneal nerve was found between the tendons of the extensor hallucis longus and the extensor digitorum longus in the majority of specimens, while the medial dorsal cutaneous nerve was almost exclusively found on the extensor digitorum longus tendon. The sural and tibial nerves were located around halfway between the most prominent point of the relevant malleolus and the posterior border of the Achilles tendon. In conclusion, this study describes easily identifiable, palpable bony and soft tissue landmarks that could be used to locate the nerves around the ankle.

Fluorescent labeling with 5-DTAF reduces collagen fiber uncrimping in loaded tendons

A fluorescent dye commonly used to image tissues under load (5-DTAF) has previously been shown to stiffen tendons. This study hypothesized that 5-DTAF staining stiffens tendons through reduced fiber sliding, altering the rate at which crimped collagen fibers straighten under load. This was tested by using reflected cross-polarized light microscopy to measure fiber crimp period of cervine extensor digitorum longus tendon specimens under axial load. Specimens were treated with either phosphate buffered saline (negative control), genipin (positive control), or 5-DTAF. In saline treated specimens, crimp period (relative to unstretched) increased at approximately 2.5 times the applied axial strain, indicating substantial fiber sliding. In both 5-DTAF and genipin treated specimens, this ratio was reduced to 1:1, indicating no fiber sliding. These results add further evidence that care should be taken when using 5-DTAF to stain tissue for studying microscale deformations in tissues.

Percutaneous Distal Metatarsal Mini-Invasive Osteotomy: Comparison Between Standard vs Modified Intraosseous Approach: A Cadaveric Study

Category:Midfoot/ForefootIntroduction/Purpose:Minimally invasive surgery (MIS) of the forefoot has gained popularity as an alternative to traditional open procedures for the treatment of metatarsalgia and hammertoe deformity. Distal metatarsal mini-invasive osteotomy (DMMO) is an extraarticular osteotomy done in a percutaneous manner, with minimal soft tissue dissection that permits elevation as well as shortening. However, there is concern for damage to vital structures due to lack of direct visualization. The objective of the study was to evaluate the structures at risk in standard versus modified DMMO.Methods:11 thawed fresh-frozen cadaveric specimens underwent minimally invasive DMMO using both the standard and modified approach. The standard technique was performed by moving the burr in a circular motion with an angle of 45° (right- handed surgeon), which cut sequentially the left, plantar, right and dorsal cortices. It was compared to a modified intraosseous technique requiring less wrist supination while remaining intraosseous. After completion of the procedures, the cadavers were fully dissected and analysed to identify unintentional injury to soft tissue structures and to verify if cuts were completely extraarticular and performed with proper angulation.Results:In the standard group the most commonly injured structures were the metatarsal joint capsules (MJC) (27%), extensor digitorum longus (EDL) (18%), and extensor digitorum brevis (EDB) (9%). The modified intraosseous group demonstrated injury to the EDL (27%), while MJC (0%) and EDB (0%) were not damaged. Distances between osteotomies and structures were 6.08 +- 3.99 mm from the dorsal metatarsal head articular surface (DMHAS), 4.85 +- 2.45 mm from EDB and 0.76 +- 1.72 mm from the EDL in the standard group and 9.92 +- 3.42 mm from the DMHAS, 4.71 +- 3.24 mm from EDB and 1.24 +- 1.84 mm from the EDL in the modified group. Statistically significant difference was found among osteotomy site and DMHAS (p=0.02).Conclusion:The most frequently injured structure was the EDL tendon with both DMMO techniques used. Intra-articular positioning of the osteotomy was more frequently observed in the standard technique. There was also a statistically significant difference between the distance of the osteotomy site and the dorsal metatarsal head articular surface when comparing the standard group and the modified group. Overall, it appears that the modified method could be a safer, less complex alternative to the standard DMMO technique, especially for the inexperienced surgeons.

Morphological diversity of peroneus tertius: a cadaveric study

Objective: The objective of this study was to demonstrate morphological anatomical variations of the peroneus tertius muscle which may have important clinical and surgical implications. Materials and methods: Fifty four specimens of anterior compartment of the leg which were dissected routinely according to the undergraduate course were examined for variations of the above muscles and the anatomy was further defined using appropriate dissection methods. Results: A wide variation was found with regard to the morphology of peroneus tertius and the extensor digitorum longus muscles with considerable differences between the legs of the same cadaver. When considering important variations deviating considerably from the normal structure, a variation of the distal attachment of peroneus tertius muscle in two specimens revealed that in addition to the normal attachment to the shaft of the fifth metatarsal, an additional slip inserted to the extensor expansion of the fifth toe. It apparently replaced the fourth tendon of extensor digitorum longus, which only had three divisions in these specimens. Seventeen of the specimens had a single muscle belly giving rise to 5 tendons which had the usual distal attachments of the peroneus tertius and the extensor digitorum longus muscle as stated below. Absence of peroneus tertius was noted in one specimen. Conclusion: The anatomical structure of the peroneus tertius vary substantially from individual to individual, inclusive of differences existing between the left and the right lower limbs of the same cadaver.

Anatomical Variations of the Peroneus Tertius and Extensor Digitorum Longus Muscles – Case Presentation

Abstract Introduction: The extensor digitorum longus and peroneus tertius muscles have multiple morphological variations. The tendinous slips of these muscles are used as grafts to replace other damaged tendons. Case presentation: We present a unique anatomical variant observed during dissection of a cadaver at the Department of Anatomy and Embryology of the “George Emil Palade” University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, Romania. The peroneus tertius muscle was identified on the left lower extremity as originating from the inferior third of the fibula and interosseus membrane. The posterior belly of this muscle joins the muscular belly of the extensor digitorum longus muscle. The tendons of toes II to V detach from the extensor digitorum longus muscle with an additional tendon. This last tendon gives off an accessory tendinous slip; lateral to this, the peroneus tertius muscle tendon is observed. In case of the right lower limb we also noted the peroneus tertius muscle originating from the distal part of the extensor digitorum longus muscle. Regarding the extensor digitorum longus muscle we describe an accessory tendinous slip. Conclusion: The anatomical variation reported in this study is similar to those reported by previous studies, but displays particular characteristics regarding the VI tendon of extensor digitorum longus and the joining of the peroneus tertius and extensor digitorum longus muscles in the left lower extremity.

Tendon transfer for dysfunction of all tendons in leg excepting Achilles tendon and plantaris tendon following irreparable sciatic nerve palsy – A case report

Introduction and importanceIrreparable sciatic nerve palsy is a cause of foot drop and resulting in absent or weak most of the muscles in leg. There may be dysfunctions of all tendons in the leg excepting Achilles tendon and plantaris tendon. The treatment of this atypical neurologic injury has not been defined.Case presentationI reported a case of foot drop following irreparable sciatic nerve palsy in which there was a dysfunction of all tendons in leg excepting Achilles tendon and plantaris tendon. The medial gastrocnemius tendon and plantaris tendon were transferred into the anterior tibialis tendon, the extensor digitorum longus tendon and extensor hallucis longus tendon. The lateral gastrocnemius tendon was transferred into the peroneus brevis. Four months post-operative, he reported no pain and became capable of walking without the assistance of an orthosis or a crutch and without steppage gait.Clinical discussionAnterior transfer of the tibialis posterior tendon was the preferred procedure. If no posterior tibial tendon function was presented, then in order of preference, the extensor hallucis longus, extensor digitorum longus, peroneal, flexor hallucis longus tendon, medial gastrocnemius, lateral gastrocnemius and plantaris tendon would be used.ConclusionThe atypical dysfunction of all tendons in the leg excepting Achilles tendon and plantaris tendon following irreparable sciatic nerve palsy was presented. Tendon transfer using medial gastrocnemius tendon, lateral gastrocnemius tendon and plantaris tendon seemed to be a good choice for treatment of this injury. It allowed reconstruction of a stable, painless, plantigrade foot.Level of evidenceCase report.

Endoscopic Ganglionectomy of the Extensor Digitorum Longus Tendon: An Extraganglionic Approach

AbstractGanglion is the most common soft tissue mass in the foot and can be painful and affect comfort wearing shoes. The usual treatment of a ganglion is conservative: careful neglect, manual rupture, or aspiration. When the lesion is recurrent or painful, surgical excision is recommended. The purpose of this Technical Note is to describe the extraganglionic approach of endoscopic ganglionectomy of the extensor digitorum longus tendon. This surgery has the advantage of being minimally invasive and having better cosmetic result, with less surgical trauma to the soft tissue. Level of EvidenceLevel 1: foot and ankle; Level 2: other (ganglion).

Correction of Crossover Toe Deformity by Plantar Plate Tenodesis and Arthroscopic Release of Lumbrical

Plantar plate deficiency is the major cause of instability of the metatarsophalangeal joint. As the joint subluxates dorsally, the lumbrical is tethered on the medial side of the joint by the deep metatarsal ligament and becomes a deforming force for the development of crossover toe deformity. Release of the lumbrical is needed to achieve adequate medial soft-tissue release. Plantar plate tenodesis has been described to correct the deformity by suturing the plantar plate to the extensor digitorum longus tendon. The purpose of this Technical Note is to incorporate the technique of arthroscopic release of the lumbrical tendon into the technique of plantar plate tenodesis.

Isolated partial tear of extensor digitorum longus tendon with overlying muscle herniation in acute ankle sports injury: role of high resolution musculoskeletal ultrasound

Lateral Ankle sprain is a common sports-related trauma with the mechanism of injury ranging from inversion to plantar flexion. These injuries commonly affect the ligaments but can also affect the associated soft tissue structures like the eversion muscles and tendons. Prompt and accurate diagnosis of such injuries is warranted so as to ensure early return to play and prevent long-term complications. Lateral ankle sprain injuries in sports may not always be associated with ligament injuries. We report a never before reported case of lateral ankle sprain injury in a soccer player with the unusual finding of isolated partial tear of Extensor digitorum longus muscle and its fascia leading to myo-fascial herniation. The lateral ankle ligaments were intact. The diagnosis was clinched on a high-frequency ultrasound scan supported by dynamic maneuvers which in fact proved to be superior to MRI as the latter failed to demonstrate the myo-fascial herniation in our case. We therefore propose that real-time ultrasound scanning with dynamic maneuvers should be the first line of investigation to assess sports injuries in anatomically complex joints like the ankle.

Single versus double tendon transfer for foot drop due to post-traumatic common fibular nerve palsy.

To compare functional outcomes of single versus double tendon transfer for foot drop correction and toe drop prevention in posttraumatic common fibular nerve palsy. A retrospective study was conducted on data from patients with posttraumatic common fibular nerve palsy treated by tendon transfer between 2001 and 2018. In cases of single tendon transfer (STT) the tibialis posterior (TP) tendon was transferred anteriorly through the interosseous membrane to a new insertion on the lateral cuneiform. In cases of double tendon transfer (DTT), the same TP tendon transfer was combined with a transfer of the flexor digitorum longus to the extensor digitorum longus and extensor hallucis longus tendons. Functional assessment was based on the Carayon score to evaluate foot drop correction and on the Yeganeh score to evaluate toe drop prevention. A total of 27 patients were included: 13 in the STT group and 14 in the DTT group. Functional results were comparable between groups in terms of reduction of foot drop, active range of ankle motion and Carayon score. Prevention of toe drop, active toe extension and Yeganeh score were significantly greater in the DTT group, however, active toe extension of was only restored in only 8 cases in the DTT group. Double transfer of TP and FDL tendons is a reliable method to restore balanced ankle dorsiflexion and prevent toe drop. However, recovery of active toe extension was inconsistent and Carayon scores were not superior to those obtained with a single TP tendon transfer.

Direct reconstruction of chronic extensor digitorum longus tendon rupture using interposed scar tissue in the foot

Rationale:Primary repair of acute ligament injury is possible due to the proximity of the ends. In the case of chronic injury, however, primary repair is difficult because the ends of ruptured ligament will have receded, and tendon graft, transfer, or reconstruction is needed. Satisfactory clinical results have been reported after reconstruction with newly formed interposed scar tissue between the ends of the ruptured tendon in chronic Achilles tendon injury and chronic extensor halluces longus (EHL) tendon injury. Here, we report a patient treated with reconstructive surgery using well-formed scar tissue between the ends in a case of chronic EDL tendon rupture.Patient concerns:A 34-year-old woman visited the clinic with pain in the dorsum aspect of the right foot associated with weakness and loss of extension of the second toe. She had sustained an injury to the dorsal aspect of her foot by falling on broken glass 3 months before coming to our clinic. The patient reported pain and limitation of the extension of the second toe for 2 months. Her pain continued to worsen, and 1 month later she was transferred to our hospital because a different local clinician suspected she had ruptured her second EDL tendon.Diagnosis:Magnetic resonance imaging (MRI) revealed complete rupture of the second EDL tendon at the metatarsal neck junction, with displacement of the distal end to the proximal phalanx shaft area and of the proximal end to the metatarsal shaft area.Interventions:Chronic rupture of the EDL tendon was treated with direct reconstruction using interposed scar tissue.Outcomes:At the 3-month follow-up, the patient was almost asymptomatic and had nearly full range of motion in dorsiflexion of the second toe. She has no discomfort in her daily life and has returned to almost her preoperative level of functional activities.Lessons:Here, we presented an extremely rare case of reconstruction using interposed scar tissue in a patient with neglected EDL tendon rupture. Direct reconstruction using interposed scar tissues located between the ends of the ruptured tendon is considered a reliable method with satisfactory clinical results in carefully selected patients.

Extensor Tendon Transfers for Treatment of Foot Drop in Charcot-Marie-Tooth Disease: A Biomechanical Evaluation

Category:Midfoot/Forefoot; Ankle; Lesser Toes; OtherIntroduction/Purpose:Transfer of the Extensor hallucis longus (EHL) and extensor digitorum longus (EDL) tendons is an underutilized procedure for the treatment of drop foot in patients with Charcot-Marie-Tooth disease (CMT). Transfer of these tendons should be considered for augmentation of ankle dorsiflexion in the CMT population, regardless of the presence of clawed toes. The preferred site for tendon transfer, however, remains unknown. We hypothesized that EHL/EDL transfers will improve ankle dorsiflexion compared to the intact state but will produce similar motion at either the metatarsal necks or cuneiforms.Methods:Eight fresh-frozen cadaveric specimens transected at the mid-tibia were mounted into a specialized jig with the ankle held in 20 degrees of plantarflexion. The EHL and EDL tendons were isolated and connected to linear actuators with suture. Diodes secured on the 1st metatarsal, 5th metatarsal and tibia provided optical data for tibiopedal position in 3-dimensions. After preloading, the tendons were tested at 25%, 50%, 75% and 100% of maximal physiologic force for the EHL and EDL muscles, individually and combined.Results:Transfers to metatarsal and cuneiform locations significantly improved ankle dorsiflexion compared to the intact state. No difference was observed between these transfer sites. Following transfer, only 25% of maximal force by combined EHL and EDL was required to achieve a neutral foot position.Conclusion:Transfer of the long toe extensors, into either the metatarsals or cuneiforms, significantly increases dorsiflexion of the ankle. Transfer should be considered for augmentation of dorsiflexion in the CMT population, regardless of the presence of clawed toes. This study supports tendon transfers into the cuneiforms, which involves less time, fewer steps and easier tendon balancing without compromising dorsiflexion power.

Effect of 6 Weeks of Aerobic Training on TGF-Β1, Myostatin and Matrix Metalloproteinase 9 Genes Expression in the Tendon of Fast- and Slow-Twitch Muscles of Male Wistar Rats

Background and Aim: Tendon, like the skeletal muscle, exhibits mechanical and morphological adaptations resulted from exercise training; however, little is known about the basic cellular and molecular mechanisms that regulate these responses. The aim of the present study was therefore to investigate the effect of 6 weeks of aerobic training on the TGF-β1, myostatin and MMP9 mRNAs expression in the tendon of fast- and slow-twitch muscles. Methods &amp; Materials For this purpose, 12 male Wistar rats at 8 weeks of age were randomly divided into two groups: experimental (n=6) and control (n=6). The exercise group performed aerobic training for 6 weeks, 5 sessions per week. Forty-eight hours after the last training session, all rats were sacrificed and the tendons of soleus and Extensor Digitorum Longus (EDL) muscles were extracted. Expression of TGF-β1, myostatin and MMP9 mRNAs were assayed using RealTime-PCR. Independent t-test was also used for statistical analysis. Ethical Considerations: All stages of the study were conducted according to the ethical guidelines and authorization of Research Deputy of Islamic Azad University, Central Tehran Branch No. IR.IAU.PS.REC.1398.296. Results: The results showed that the expression of TGF-β1 mRNA in EDL and soleus tendons significantly increased (P≤0.001), whereas the expression of myostatin in EDL tendon was significantly reduced (P≤ 0.001). Increased mRNA expression of MMP9 in the tendon of EDL and soleus muscles was not statistically significant (P&gt;0.05). Conclusion: It seems that aerobic exercise can modulate the expression of genes involved in the regulation of tendon collagen in a muscle type-dependent manner.

Anatomic and Histological Features of the Extensor Digitorum Longus Tendon Insertion in the Proximal Nail Matrix of the Second Toe.

Background: Anatomic and histological landmarks of the extensor digitorum longus (EDL) tendon insertion in the proximal nail matrix may be key aspects during surgery exposure in order to avoid permanent nail deformities. Objective: The main purpose was to determine the anatomic and histological features of the EDL’s insertion to the proximal nail matrix of the second toe. Methods: A sample of fifty second toes from fresh-frozen human cadavers was included in this study. Using X25-magnification, the proximal nail matrix limits and distal EDL tendon bony insertions were anatomically and histologically detailed. Results: The second toes’ EDLs were deeply located with respect to the nail matrix and extended superficially and dorsally to the distal phalanx in all human cadavers. The second toe distal nail matrix was not attached to the dorsal part of the distal phalanx base periosteum. Conclusions: The EDL is located plantar and directly underneath to the proximal nail matrix as well as dorsally to the bone. The proximal edge of the nail matrix and bed in human cadaver second toes are placed dorsally and overlap the distal EDL insertion. These anatomic and histological features should be used as reference landmarks during digital surgery and invasive procedures.

Extensor Tendon Transfers for Treatment of Foot Drop in Charcot-Marie-Tooth Disease: A Biomechanical Evaluation.

In Charcot-Marie-Tooth (CMT) disease, selective weakness of the tibialis anterior muscle often leads to recruitment of the long toe extensors as secondary dorsiflexors, with subsequent clawing of the toes. Extensor hallucis longus (EHL) and extensor digitorum longus (EDL) tendon transfers offer the ability to augment ankle dorsiflexion and minimize claw toe deformity. The preferred site for tendon transfer remains unknown. Our goal was to quantify ankle dorsiflexion in the "intact" native tendon state, compared with tendon transfers to the metatarsal necks or the cuneiforms. We hypothesized that EHL and EDL transfers would improve ankle dorsiflexion as compared with the intact state and would produce similar motion when anchored at the metatarsal necks or cuneiforms. Eight fresh-frozen cadaveric specimens transected at the midtibia were mounted into a specialized jig with the ankle held in 20 degrees of plantarflexion. The EHL and EDL tendons were isolated and connected to linear actuators with suture. Diodes secured on the first metatarsal, fifth metatarsal, and tibia provided optical data for tibiopedal position in 3 dimensions. After preloading, the tendons were tested at 25%, 50%, 75%, and 100% of maximal physiologic force for the EHL and EDL muscles, individually and combined. Transfers to metatarsal and cuneiform locations significantly improved ankle dorsiflexion compared with the intact state. No difference was observed between these transfer sites. Following transfer, only 25% of maximal force by combined EHL and EDL was required to achieve a neutral foot position. Transfer of the long toe extensors, into either the metatarsals or cuneiforms, significantly increased dorsiflexion of the ankle. The transferred extensors can serve a primary role in treating foot drop in CMT disease, irrespective of the presence of clawed toes. This biomechanical study supports tendon transfers into the cuneiforms, which involves less time, fewer steps, and easier tendon balancing without compromising dorsiflexion power.

Normal anatomical and diagnostic imaging techniques of the musculotendinous structures of the ostrich (Struthio camelus) foot.

Objective:The objective of this work was to study the normal musculotendinous structures of the ostrich foot.Materials and methods:Ten African apparent healthy adult female ostriches (Struthio camelus) were slaughtered, and the pelvic limbs were separated from the ankle joint. The different biomedical scanning techniques including radiography, computed tomography (CT), magnetic resonance imaging, and ultrasonography were achieved. Then, the ostrich feet were freshly dissected.Results:The radiographs and CT images showed the bony components of the ostrich foot that revealed the presence of long tarsometatarsus and phalanges of the only developed third and fourth toes. The third digit was the longest and possessed four phalanges, whereas the shorter fourth toe contained five phalanges. The ostrich foot consisted mainly of tendons in addition to several small associated muscles. The extensor structures were the extensor digitorum longus tendon, Mm. extensor proprius digiti III, and extensor brevis digiti III and IV. On the other hand, the flexor structures were the flexor digitorum longus, flexor hallucis longus, flexor perforans et perforatus digiti III, and flexor perforatus digiti III and IV tendons. Furthermore, fibularis longus tendon and two muscles (Mm. abductor digiti IV and lumbricalis) were related to the flexor tendons.Conclusion:The combination between the dissecting anatomy and the different biomedical scanning techniques was of value in describing the normal anatomical course of the musculotendinous structures of the ostrich foot, which aids in the diagnosis of any clinical abnormalities in these structures.