Anatomic bases of ankle arthroscopy: study of superficial and deep peroneal nerves around anterolateral and anterocentral approach

Summary We studied the anatomy of the anterolateral and anterocentral portal sites for ankle arthroscopy with reference to the superficial peroneal nerve (SPN) in 29 cadavers (51 ankles) and the deep peroneal nerve (DPN) in 11 cadavers (21 ankles). In relation to the level of division into the medial and intermediate cutaneous nerves and their terminal branches, we classified the structure of the SPN surrounding the ankle into five types. We also identified the point where the SPN and the DPN cross the level of the talocrural joint. 32% of specimens had different SPN division types on the two sides and there was an average of 2 nerves at the level of the talocrural joint. Branches of the SPN were found lateral to the edge of the peroneus tertius tendon in 11.8% of specimens, and at its lateral edge in 27.5%. The DPN and some branches of the SPN were positioned around the lateral edge of the extensor hallucis longus tendon. We consider that the anterolateral portal should be made at least 2 mm lateral to the peroneus tertius tendon to avoid injury to the SPN, since the diameter of the scope is 2.7 mm. The anterocentral portal is unsuitable for arthroscopy due to a high risk of injury to the DPN and branches of the SPN.

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Etude anatomique des nerfs fibulaires superficiel et profond au niveau des voies antéro-latérale et antéro-centrale pour arthroscopie de la cheville

Résumé Nous avons étudié l'anatomie des voies antéro-latérale et antéro-centrale pour arthroscopie de la cheville, et notamment leur rapport avec le n. fibulaire superficiel (NFS) sur 29 cadavres (51 chevilles) et le n. fibulaire profond (NFP) sur 11 cadavres (21 chevilles). Par rapport au niveau de division des nn. cutanés médial et intermédiaire et de leurs branches terminales, nous avons classé la disposition du NFS en regard de la cheville dans 5 types. Nous avons identifié le point où le NFS et le NFP croisaient l'interligne articulaire talo-jambier. 32% des spécimens présentaient un site de division du NFS différent à droite et à gauche, et il y avait en moyenne deux nerfs en regard de l'art. talo-jambière. Les branches du NFS étaient latérales au bord du tendon du m. troisième fibulaire dans 11,8 % des cas, en regard de son bord latéral dans 27,5% des cas. Le NFP et quelques branches du NFS se trouvaient en regard du bord latéral du tendon du m. long extenseur de l'hallux. Nous pensons que la voie antéro-latérale devrait être réalisée au moins 2 mm latéralement au tendon du m. troisième fibulaire pour éviter la blessure du NFS, car le diamètre de l'endoscope est de 2,7 mm. La voie antéro-centrale est, pour nous, inappropriée pour l'arthroscopie de la cheville en raison d'un risque élevé de la blessure du NFP et des branches du NFS.

     

Navigation for ankle arthroscopy: anatomical study of the anterolateral portal with reference to the superficial peroneal nerve

We aimed to navigate the surgeon regarding the localization of the main anatomical structures at the anterior part of the ankle joint, in order to find easily the safest anatomical points with reference to the superficial peroneal nerve (SPN), in particular for anterolateral portal placement in ankle arthroscopy. Sixty-three ankles in 36 fresh cadavers were dissected. In all specimens we examined (1) the distance between the SPN bifurcation and the most distal point of the lateral malleolus; and at the level of ankle joint, (2) the number of SPN, (3) the distance between the medial and intermediate dorsal cutaneous nerves, which are branches of the SPN, (4) the localization of the peroneus tertius (PT) tendon in relation to the lateral malleolus, (5) the width of the extensor digitorum longus (EDL) tendon, (6) the relationship of the PT tendon and (7) the relationship of the extensor hallucis longus (EHL) tendon with the SPN. The results were as follows: (1) In 41 ankles with bifurcation (65%) the average distance was 71.8±35.3 mm. (2) There were two SPN branches in 39 (62%), three branches in seven (11%) and one branch in 17 (27%) cases. (3) In 39 ankles with two branches of the SPN, the mean distance was 15.2±7.1 mm. (4) The lateral border of the PT tendon was positioned a mean distance of 20.8±3.3 mm proximal and 25.2±5.8 mm medial to the reference points. (5) The mean width was 10.1±2.9 mm. (6) In 42 ankles (67%) the distance between the lateral border of the PT tendon and the SPN was a mean of 6.2±6.6 mm, median of 3 mm (range 0–22 mm lateral to the tendon). (7) In 56 cases (89%) a branch of the SPN was found a mean of 6.6±4 mm and a median of 6 mm lateral to the EHL tendon, and in seven cases (11%) on the tendon. According to our study, in ankle arthroscopy the risk of the SPN injury is maximal in the 0–3 mm lateral to the PT tendon. To avoid injury to the SPN, the safest placement of the anterolateral portal is 4 mm lateral to the PT tendon.     

Longitudinal Split of the Peroneus Brevis Tendon and Lateral Ankle Instability: Treatment of Concomitant Lesions

OBJECTIVE: To describe the clinical picture, pathophysiology, and treatment of concomitant lesions of the peroneus brevis tendon and lateral ligament injuries to the ankle. BACKGROUND: In some cases, chronic lateral ankle instability is associated with a longitudinal partial tear in the peroneus brevis tendon. Patients who suffer from this lesion usually have atypical posterolateral ankle pain combined with signs of recurrent ligament instability ("giving way"). The tendon injury is often overlooked because it is combined with the ligament injury, and the injury mechanisms are similar. DESCRIPTION: Tears or laxity in the superior peroneal retinaculum allow the anterior part of the injured peroneus brevis tendon to ride over the sharp posterior edge of the fibula, leading to a longitudinal tear in the tendon. This combined injury should be suspected in patients with recurrent giving way of the ankle joint and retromalleolar pain. The diagnosis can be established using either ultrasonography or magnetic resonance imaging. DIFFERENTIAL DIAGNOSIS: Ligament injury, tenosynovitis, peroneus longus tendon lesion, os peroneum fracture, distal peroneus brevis tendon tear, or anomalous peroneus tertius tendon. TREATMENT: The tendon injury and the ligament insufficiency should be repaired at the same time. CONCLUSIONS: We recommend reconstruction of the superior peroneal retinaculum, combined with repair of the tendon, using side-to-side sutures and anatomical reconstruction of the lateral ankle ligaments.     

The consistent presence of the human accessory deep peroneal nerve

Twenty-four human legs were dissected macroscopically to study the morphological details of the accessory deep peroneal nerve. This nerve arose from the superficial peroneal nerve and descended in the lateral compartment of the leg, deep to peroneus longus along the posterior border of peroneus brevis. Approaching the ankle joint, this nerve passed through the peroneal tunnels to wind around the lateral malleolus; it then crossed beneath the peroneus brevis tendon anteriorly to reach the dorsum of the foot. The accessory deep peroneal nerve was found in every case examined and constantly gave off muscular branches to peroneus brevis and sensory branches to the ankle region. In addition, this nerve occasionally had muscular branches to peroneus longus and extensor digitorum brevis, and sensory branches to the fibula and the foot. The anomalous muscles around the lateral malleolus were also innervated by this nerve. Neither cutaneous branches nor communicating branches with other nerves were found. The present study reveals that the accessory deep peroneal nerve is consistently present and possesses a proper motor and sensory distribution in the lateral region of the leg and ankle. It is not an anomalous nerve as has previously been suggested.     

踝关节外侧韧带和距下关节韧带修复重建的应用解剖

目的 :为踝关节外侧韧带和距下关节韧带损伤修复重建提供解剖学基础。方法 :在 3 2侧经防腐固定、8侧冷藏新鲜标本上解剖观测踝关节外侧韧带和距下关节韧带及小趾趾长伸肌腱、第 3腓骨肌腱、腓骨短肌腱、伸肌下支持带 ,在新鲜标本上摹拟修复术。结果 :小趾趾长伸肌腱、第 3腓骨肌腱、腓骨短肌腱、伸肌下支持带解剖位置恒定 ,与踝关节外侧韧带和距下关节韧带相毗邻 ,具有一定的长、宽、厚度 ,可形成移植供体。结论 :①陈旧性踝关节外侧韧带和距下关节韧带的损伤 ,原位修复较难 ,用肌腱转位修复是一种可行的方法 ;②可用腓骨短肌腱修复距腓前和跟腓韧带损伤 ,小趾趾长伸肌腱和第 3腓骨肌腱转位修复距下关节韧带 ,伸肌下支持带可用作加强缝合 ,术式经标本摹拟具有可行性。     

The communicating branches between the sural and superficial peroneal nerves in the foot: a review of 55 cases

The rich sensory innervation of the ankle and foot is manifest through the numerous communicating branches linking the neural trunks, particularly the superficial peroneal and sural nerves on the anterolateral aspect of the hindfoot. The 35 communicating branches seen in 55 dissections (58%) were proximal in half of the cases, lying in the malleolar and lateral tarsal regions, and distal in the other half, in the metatarsal region. The communicating branch was straight in 25 cases and curved in 11. The average distances of the communicating branch from the crest of the lateral malleolus and the tubercle of the 5th metatarsal was 4.7 and 4.1 cm, but there was a wide range of values. We believe that stretching of the proximal communicating branch during forced inversion of the ankle and/or foot or during fractures of the calcaneus or direct injury in surgical approaches or arthroscopy of the ankle may lead to unexplained pre- and submalleolar pain. Advances in modern imaging may allow recognition of these branches and guidance of infiltration and even neurolysis in cases of failure of conservative treatment.     

Accessory peroneal nerves in the human

The Nervus peroneus profundus accessorius was described by Ruge (1878) in the lower mammals and for the first time identified by Bryce (1897) in man. It is an accessory terminal branch of the superficial peroneal (musculocutaneous) nerve which winds round the lateral malleolus beneath the tendons of the peronei muscles and reaches the dorsum of the foot; there it often supplies the lateral portion of the extensor digitorum brevis muscle. In further investigations this nerve has been traced in 21.2% of subjects resp. in 13.5% of legs. This nerve, however, is not the only accessory branch of the common peroneal nerve: In 14 out of 140 subjects (10%) resp. in 22 out of 280 legs (7.9%) a Nervus peroneus superficialis accessorius has been found. This nerve pierces the anterior crural intermuscular septum either in common with deep peroneal (anterior tibial) nerve or at a lower point. Then it descends in front of the septum rarely giving off muscular branches to the extensor digitorum longus and peroneus tertius muscles; in the lower half of the leg it pierces the crural fascia, passes in front of the ankle joint and becomes the medial cutaneous nerve of the dorsum of the foot. This accessory superficial peroneal nerve may be of importance in surgery of the leg and foot.     

Anatomy of the superficial peroneal nerve related to the harvesting for nerve graft

The superficial peroneal nerve (SPN) is one of the two main branches of the common peroneal nerve, which become cutaneous nerve on the lateral side of distal leg and dorsum of foot. The use of SPN as nerve graft has been introduced; however, important data regarding the morphometric anatomy of this nerve and its branches, medial and intermediate dorsal cutaneous nerves (MDN and IDN, respectively) to support this application remain incomplete. Eighty-five legs of cadavers were dissected and the branching pattern was classified into Type 1 (penetration of the main trunk of SPN from the deep fascia) or Type 2 (separate penetration of the MDN and IDN). The length of SPN, MDN and IDN from the penetration points until before subsequent branching was measured. In addition, the penetration points were located by referring to the intermalleolar line and the lateral malleolus. Type 1 was found in the majority of specimens independent of gender (71.8%). Asymmetry in the branching pattern was observed in nine cases (20.9%). The average length of the SPN, MDN and IDN without branches was 7.7, 8.1 and 5.5 cm, respectively. The penetration points of the SPN, MDN and IDN were located 5.1, 7.6 and 5.5 cm above the intermalleolar line, respectively. These data are important for using the SPN as a graft.     

The innervation of the joints of the foot

The nerve supply of the ankle joint and of the joints of the foot was studied in dissections of fetal and adult feet and in serial sections of fetal feet stained with silver. The ankle joint was supplied by the tibial, sural, deep peroneal, and saphenous nerves, and by the accessory deep peroneal nerve when present. The tarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves, and on their dorsal aspects chiefly by the deep peroneal nerve. The joint between the lateral and intermediate cuneiform received branches from the intermediate dorsal cutaneous nerve also. The lateral dorsal cutaneous nerve and the accessory deep peroneal nerve when present provided additional branches to the subtalar and calcaneocuboid joints. The tarsometatarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves. Most of them were supplied on their dorsal aspects by the deep peroneal nerve, but the cuboid-metatarsal joints received their supply from the intermediate dorsal cutaneous nerve. The intermetatarsal joints had a similar but sparser supply. The joint between the fourth and fifth metatarsal received branches from the intermediate dorsal cutaneous nerve. The plantar digital nerves provided the main supply to the metatarsophalangeal joints. The dorsal aspect of the first metatarsophalangeal joint was supplied by the deep peroneal and the medial dorsal cutaneous nerves, of the second metatarsophalangeal joint by the deep peroneal nerve, and of the fourth and fifth metatarsophalangeal joints by the lateral dorsal cutaneous nerve. The interphalangeal joints did not receive articular branches from the dorsal digital nerves, except in the case of the interphalangeal joint of the big toe, which was supplied by the deep peroneal and the medial dorsal cutaneous nerves.     

The possibility of deep peroneal nerve neurotisation by the superficial peroneal nerve: an anatomical approach

Neurotisation involves transfer of nerves for the restoration of function following injury. A number of nerves have been used in different part of the peripheral nervous system. This study was undertaken to develop a practical and relatively safe surgical approach to the treatment of L4 root lesion's. We examined the effectiveness and safety of neurotisation of the deep peroneal nerve and its branches by the superficial peroneal nerve. Twelve legs of dissected cadavers provided for teaching purposes in the anatomy laboratory were used to display the common peroneal nerve and its branches. Each branch was measured using calipers and analysed to investigate the possibility of neurotisation of the deep peroneal nerve by the superficial peroneal nerve and its branches. It was found that of the measured branches, transposition was possible between those to peroneus longus and tibialis anterior on the basis of their diameter and length. In recent decades, advances in microsurgical reconstruction and understanding of the microanatomy have played major roles in improving the results of surgical treatment of nerve injuries. There is a need for further experimental studies on the feasibility of this surgical approach.     

Sural-tibial nerve communications in humans

We investigated the occurrence of a communication between the sural and tibial nerves in 49 legs of 28 Japanese cadavers. In front of the calcanean tendon, we found the communication in 7 legs (14.3%) or in 5 cadavers (18.9%). The sural nerve gave rise to a number of medial and lateral branches, including the lateral calcanean branch at the lateral side of the ankle. The communicating branch with the tibial nerve arose from the first medial branch and pierced the deep fascia of the leg. In 4 cases, the U-shaped communication was formed between the sural and tibial nerves, and in 3 cases, the Y-shaped communication. Electrophysiologi-cal evidence of an anomalous motor function of the sural nerve has been reported recently. We consider that the U-shaped communication between the sural and tibial nerves gives a morphological basis to the motor function of the sural nerve.     

Formation and distribution of the sural nerve based on nerve fascicle and nerve fiber analyses

The formation and distribution of the sural nerve are presented on the basis of an investigation of 31 legs of Japanese cadavers using nerve fascicle and fiber analyses. Nerve fibers constituting the medial sural cutaneous nerve were designated as 'T', whereas those constituting the peroneal communicating branch were designated as 'F'. In 74.2% of cases (23/31), the T and F fibers joined each other in the leg, whereas in 9.7% of cases (3/31) they descended separately. In 16.1% of cases (5/31), the sural nerve was formed of only the T fibers. The sural nerve gave off lateral calcaneal branches and medial and lateral branches at the ankle. The lateral calcaneal branches always contained T fibers. The medial branches consisted of only T fibers, whereas most of the lateral branches consisted of only F fibers (71.0%; 22/31). In addition to the T and F fibers, P fibers, which derived from the superficial and deep peroneal nerves, formed the dorsal digital nerves. The P fibers were entirely supplied to the medial four and one-half toes. However, they were gradually replaced by the T and F fibers in the lateral direction. The 10th proper dorsal digital nerve consisted of T fibers only (38.7%; 12/31), of F fibers only (19.4%; 6/31) or of both T and F fibers (38.7%; 12/31). These findings suggest that the T fibers are essential nerve components for the skin and deep structures of the ankle and heel rather than the skin of the lateral side of the fifth toe. The designation of the medial sural cutaneous nerve should be avoided and only the T fibers are appropriate components for naming as the sural nerve.     

The peroneus quartus muscle: clinical correlation with evolutionary importance

The peroneus quartus (PQ) is an accessory muscle of the peroneal/lateral compartment of the leg. The muscle has often been implicated as a cause of pain in the lateral ankle region, and subluxation or attrition of the peroneal tendons. The present study was aimed at observing the prevalence and morphology of this muscle in human cadavers. Ninety-two embalmed lower limbs were dissected for this study. The PQ muscle was found in 21% of the limbs. In all these limbs it originated from the lower part of the lateral surface of the fibula, the undersurface of peroneus brevis and the posterior intermuscular septum. In the majority of limbs, insertion was on the retrotrochlear eminence of the calcaneus. Taking into account the possibility of this muscle being a cause of lateral ankle pathology, the present study attempts to correlate the findings with the anatomy of the surrounding region. The frequent occurrence of this muscle in humans is suggestive of a progressive evolutionary change to evert the foot in order to assume a bipedal gait.     

肘关节镜三种远端前外侧入路对周围神经损伤风险比较

目的：比较肘关节镜3 种远端前外侧入路穿刺后对前臂外侧皮神经及桡神经（ 深支）的影响。 方法：选用 新鲜冰冻的成人肘关节标本,关节镜下对3 种入针点（ 肱骨外上髁远端3 cm,前方1 cm ;肱骨外上髁远端2 cm, 前方2 cm ;肱骨外上髁远端1 cm,前方1 cm）进行定位、穿刺克氏针,并在肘关节屈曲90°时,解剖、测量与 前臂外侧皮神经及桡神经（ 深支）的最短距离。结果：3 种入路距前臂外侧皮神经的最短距离分别为（18.51±2.07） mm、（19.14±1.53）mm、（21.95±1.83）mm,距桡神经（ 深支）的最短距离分别为（7.18±1.17）mm、（7.59±0.88） mm、（9.22±1.51）mm。后一入路点（ 肱骨外上髁远端1 cm,前方1 cm）距2 条神经的距离为最短,且与前2 者 的差异具有统计学意义。结论：肘关节镜前外侧入路（ 肱骨外上髁远端1 cm,前方1 cm）距前臂外侧皮神经及桡 神经（ 深支）的最短距离最远,建立远端前外侧入路时选此入路穿刺比较安全。     

Relationship between the deep peroneal nerve and dorsalis pedis artery in the foot: a cadaveric study

The aim of our work was to study the relationship between deep peroneal nerve (DPN) and dorsalis pedis artery (DPA) so that the frequency of these variations can be kept in mind by the angiographers and surgeons to ensure safe surgical approach during flap surgery. Ninety-two legs in 46 cadavers were dissected to study the relationship between DPN and DPA on the dorsum of the foot. The relationship of neurovascular bundle of the dorsum of the foot was classified into four types. Type I: division of the DPN distal to the midpoint between the two malleoli (observed in 26 limbs). In Type II, the division of the DPN was midway between the two malleoli (seen in 20 limbs). Both Type I and II are further divided into two subtypes (a and b) depending upon the crossing pattern of terminal branches of the DPN over DPA. In Type III, multiple branches of DPN were noted in two limbs. In Type IV, the looping pattern of DPN around the DPA was considered and was seen in eight limbs. Awareness of possible variations in the relationship of the DPA to DPN on the dorsum of the foot is important for vascular and reconstructive surgeons. Because it might help in decreasing confusion when considering treatment options like microvascular anastomosis in reconstruction of the leg.     

An unique variation of the peroneus tertius muscle

Peroneus tertius (fibularis tertius) is a muscle unique to humans. It often appears to be a part of extensor digitorum longus, and might be described as its "fifth tendon". Although its insertion variation has been reported by many authors, variations of its origin points are not common. A variation of the peroneus tertius muscle was found during routine dissection of a 75-year-old male cadaver. The muscle originated from the extensor hallucis longus. The muscle belly of the extensor hallucis longus arose from the middle two-fourths of the medial surface of the fibula, medial to the extensor digitorum longus, and anterior surface of the interosseous membrane. It lay under the extensor digitorum longus, and lateral to the tibialis anterior muscle. The muscle belly of the extensor hallucis longus divided into medial and lateral parts 17 cm below its origin point. The lateral part, named as peroneus tertius, continued downward to reach the medial part of the dorsal surface of the base of the fifth metatarsal bone. The medial part ran also downward and divided into two tendons reaching the dorsal surface of the base of the distal phalanx of the great toe. This kind of variation may be important during foot or leg surgery.     

足背皮瓣与足外侧或外踝上哑铃状联合皮瓣设计的解剖基础

目的:为手部复杂外伤并两处皮肤缺损及深部组织损伤外露的修复提供理想的皮瓣供区.方法:40侧动脉灌注红色乳胶的成人下肢标本,解剖观测胫前血管、腓血管穿支降支在踝前的分支、分布、外径及其远端吻合情况.结果:胫前动脉在踝间或踝上向外侧恒定地发出外踝前动脉.根据胫前动脉外踝前支的分出位置、粗细及与腓动脉穿支降支的吻合情况,可将其分成以下四型.两主干血管吻合后下行经外踝前至足背外侧与跗外侧动脉吻合,沿途发出皮支营养胫前踝上和足背外侧.结论:可以在形成以胫前血管为蒂的足背皮瓣同时,以胫前血管的外踝前动脉为血供设计足外侧或外踝上联合皮瓣应用.     

基于Sihler’s技术的踝和足背皮神经的整体分布模式研究

目的 揭示踝及足背皮神经的整体分布模式,为皮瓣移植感觉重建提供形态学指导。 方法 成年尸体24具,紧贴肌表面摘取含皮下脂肪的踝及足背皮肤,用改良的Sihler’s染色法显示并观察皮神经整体分布模式。 结果 在Sihler’s染色的标本中,肉眼可见隐神经支配踝前区（40.01±7.6）%、踝后区（30±6.7）%、以及部分足背内侧缘。腓浅神经支配踝前区（60.03±6.8）%,其足背内侧皮神经支配足背内侧区、第1、2趾背及第3趾背内侧半;95.83%的足背中间皮神经分布到第3趾背外侧半、第4、5趾背。腓肠神经支配踝后区（70±5.3）%,其足背外侧皮神经支配足背外侧缘皮肤。腓深神经分布到第1、2趾背相对面。初级神经支密度以踝前区最高,次级及以下神经支密度和总的神经支密度均以足背内侧区最高。 结论 在踝或足背的皮瓣移植中,建议把踝前区或足背内侧区设计为利于感觉重建的首选供区或感觉需求较高的受区。     

Lateromedial and dorsoplantar borders among supplying areas of the nerves innervating the intrinsic muscles of the foot.

The branching patterns of nerves supplying the intrinsic muscles of the foot were analyzed as a basis to confirm the muscle layer structure. Thirty-eight feet of 20 Japanese cadavers were examined in detail in this study. The first dorsal interosseus was innervated by a branch from the deep peroneal nerve as well as a branch of the lateral plantar nerve in 92.1%, the second dorsal interosseus in 10. 5% and the third dorsal interosseus in 2.6%. In three specimens, branches from the deep peroneal nerve innervated the oblique head of the adductor hallucis or the lateral head the flexor hallucis brevis. In addition, branches from the medial and lateral plantar nerves and the deep peroneal nerve formed communication loops in three specimens. The first dorsal interosseus, the oblique head of the adductor hallucis and the lateral head of the flexor hallucis and their innervating nerve branches are closely related within the first intermetatarsal space. Since the tibial part of the first interosseus muscle primordium is occupied in the space during development, the variations of innervation patterns and formation of the communicating nerve loops may be explained by various combinations of the part and the other muscle primordia.