An Anatomic and Clinical Study of the Innervation of the Dorsal Midfoot Capsule.

BACKGROUND: Dorsal pain from osteoarthritic midfoot joints is thought to be relayed by branches of the medial and lateral plantar, sural, saphenous, and deep peroneal nerves (DPN). However, there is no consensus on the actual number or pathways of the nervous branches for midfoot joint capsular innervation. This study examined the DPN's terminal branches at the midfoot joint capsules through anatomic dissection and confirmation of their significance in a clinical case series of patients with midfoot pain relief after DPN block. METHODS: Eleven cadaveric lower leg specimens, 6 left and 5 right, were dissected using operative loupe magnification. We preserved the terminal branches and recorded their paths and branching patterns. Joint capsular innervations were individually noted. To confirm our hypothesis of significant dorsal midfoot joint capsular innervation by the DPN, we also performed an institutional review board-approved retrospective chart review of 37 patients with painful dorsal midfoot osteoarthritis who underwent diagnostic local anesthetic injection block of the DPN. The percentage of temporary pain relief after the injection was recorded. RESULTS: Terminal innervation of the DPN branches showed distribution of the second and third tarsometatarsal joints in all specimens. Inconsistent innervation of the naviculocuneiform (9/11), fourth (7/11), first (6/11), and fifth (4/11) tarsometatarsal and calcaneocuboid joints (1/11) were observed. The retrospective review of pain relief in patients with dorsal midfoot pain due to arthritis after diagnostic injection demonstrated a mean of 92.1% improvement. CONCLUSION: Innervation of the dorsal midfoot joint capsule appears to follow a consistent distribution across 3 joints: second and third tarsometatarsal joints and the naviculocuneiform joint. Acute relief of dorsal midfoot arthritic pain after diagnostic injection suggests that dorsal midfoot nociceptive pain is at least partly transmitted by the DPN. LEVEL OF EVIDENCE: Level IV, case series.

A preliminary review of the use of deep peroneal neurectomy for the treatment of painful midtarsal and tarsometatarsal arthritis.

This report describes a retrospective analysis of chart and radiographic data pertaining to 10 consecutive cases performed over a 30-month period, undertaken in an effort to evaluate the preliminary efficacy of denervation for pain relief in high-risk surgical candidates with midfoot and tarsometatarsal joint arthritis. Ten patients (13 feet) were treated, and objective and subjective assessments were obtained using an index of subjective patient satisfaction. Results revealed 9 (69.2%) feet from 7 (70%) patients had greater than 75% relief. Two (15.4%) feet from 2 (20%) patients had at least 50% improvement and 2 (15.4%) feet from 1 (10%) patient claimed no relief. Our results indicate that this method of treatment can be an effective way to relieve pain associated with arthrosis involving the midfoot and tarsometatarsal joints.

The effect of the tarsal joint positions on the tibial nerve motor action potential latency in dog: electrophysiological and anatomical studies.

This study has been carried out to determine the effect of neutral position, hyperextension and hyperflexion of the tarsal joint on the tibial nerve, motor action potential latency and tarsal canal compartment pressure in dogs with the aid of electrophysiological and anatomical methods. Totally twenty healthy mongrel dogs were used. Latency of motor nerve action potential (MNAPL) studies of tibial nerve via surface stimulating and needle recording electrodes was performed on right hind limbs of all the dogs. The compartment pressures of the tarsal canal with the pressure transducer were determined from both limbs from ten of the dogs. In one dog, tarsal regions of both left and right limbs were demonstrated using magnetic resonance imaging (MRI). Two dogs were euthanatized and tarsal regions of the dogs were sectioned for correlative anatomy. Nerve conduction studies showed that the MNAP latency of the tibial nerve were 3.55 +/- 0.097 ms, 3.76 +/- 0.087 ms and 3.39 +/- 0.097 ms in neutral, hyperextension and hyperflexion positions, respectively. Hyperflexion of the tarsal joint caused prolongation of the MNAP latency of the tibial nerve with the highest pressure value being determined in tarsal canal. From the anatomical viewpoint, the distance between the flexor hallucis longus muscle and the superficial digital muscle was the shortest during hyperflexion and the plantar branch of saphenous artery, lateral and medial plantar nerves located more laterally in cadaver and MR imaging sections. As a result of this study, it is thought that tarsal region diseases as well as long time splint in the hyperflexion position as applied in the Ehmer sling can affect the compartment pressure and nerve tension because of occupying in the tarsal canal. Raising pressure and nerve stretching in the tarsal canal compartment could cause deficiencies in the conduction velocity of the tibial nerve. This might be a result of tarsal tunnel syndrome in the dog. Clinicians could consider this syndrome in cases of tarsal region diseases as well as application of long time splint in hyperflexion of tarsal joints in dogs.

Substance P immunoreactive nerve fibres in the domestic chick ankle joint before and after acute urate arthritis.

Substance P immunoreactive (SP-IR) nerve fibres were identified using fluorescence immunohistochemistry and the length of the labelled individual nerve fibres was measured using confocal microscopy of whole mounts of the lateral wall of the ankle joint in 2-week-old domestic chicks. In the normal ankle there was an extensive network of SP-IR fibres in the synovial and subsynovial tissue of the joint capsule. Fours hours after injection of sodium urate into the joint space the joint was inflamed and there was a significant reduction in the labelled nerve fibres. These results demonstrate experimentally that painful gouty arthritis produces a neurogenic depletion of substance P from peripheral nerve fibres in the synovial and subsynovial tissue.

The deep peroneal nerve in the foot and ankle: an anatomic study.

Injury to the deep peroneal nerve in the foot and ankle may result from trauma, repetitive mechanical irritation, or iatrogenic harm. The nerve is most susceptible to injury along its more distal anatomic course. Dissection of 17 cadaver specimens was undertaken to describe the course of the deep peroneal nerve and quantify its branch patterns. In the distal one third of the leg, the nerve was located superficial to the anterior tibial artery between the tibialis anterior and extensor hallucis longus muscles. Typically, the nerve crossed deep to the extensor hallucis longus tendon to enter the interval between the extensor hallucis longus and extensor digitorum longus at an average distance of 12.5 mm proximal to the ankle. A proximal bifurcation was usually present at an average distance of 12.4 mm distal to the mortise. The lateral terminal branch penetrated the deep surface of the extensor digitorum brevis to provide motor innervation. The medial terminal branch passed over the talonavicular joint capsule, and coursed an average of 2.9 mm lateral to the first tarsometatarsal joint. Within the forefoot, it passed deep to the extensor hallucis brevis tendon, bifurcated in the midmetatarsal region, and then arborized, supplying sensibility to the first toe interspace and the adjacent sides of the first and second toes.

The intermetatarsal nerve: a microscopic evaluation.

Microscopic evaluation of the interdigital neuroma is difficult because the appearance of the normal nerve has not been described precisely. In an effort to characterize the normal interdigital nerve, 104 nerves were removed at autopsy from the intermetatarsal spaces of 14 women who were more than 48 years old. A positive relationship between perineurial width and internal diameter of the nerve fascicle in web spaces 2, 3, and 4 was defined. In addition, the number and the diameter of blood vessels had a positive correlation in all web spaces. These measurements should be of help in the objective differentiation of the common interdigital neuroma from the normal interdigital nerve.