SURGICAL-TREATMENT OF PATIENTS WITH PAINFUL INSTABILITY OF THE 2ND METATARSOPHALANGEAL JOINT

An unstable second metatarsophalangeal joint may produce pain in the f orefoot. Eighteen patients (20 feet) had a transfer of the flexor digi torum longus to the extensor side of the base of the proximal phalanx performed as the primary procedure to stabilize this painful joint. Mo st patients had a hallux valgus deformity that also required correctio n, because it either was also symptomatic or was preventing adequate r eduction of the second toe. A ruptured plantar plate of the second met atarsophalangeal joint was demonstrated in 13 feet and in these joints appeared to be the cause of the vertical instability. However, all fe et showed an unstable joint upon clinical examination. A vertical-stre ss test almost always reproduced the patient's pain while demonstratin g instability in the joint; this was the most prominent physical findi ng in these patients. Eleven patients (13 feet) had an excellent resul t. Seven patients (seven feet) had a fair result, but they complained only of mild and occasional pain at the joint on exertion. Although di fficult to quantify, it appears that postoperative stiffness in the jo int provided some of the joint stability seen in our patients. The fle xor tendon transfer appears to be a satisfactory method to treating th e unstable metatarsophalangeal joint and of relieving patients' pain, but may not, however, restore a normal alignment of the second toe. Co rrection of other forefoot deformities as hallux valgus and hammertoes may also be important in restoring metatarsophalangeal stability.