Total replacement arthroplasty of the first metatarsophalangeal joint. Foot Ankle

A surface replacement prosthesis for the first metatar-sophalangeal joint has been designed to be used in ar-thritic conditions of this joint. The components are made of stainless steel and polyethylene and fixed with meth-ylmethacrylate. The surgical details of insertion are im-portant in such a complex, small joint. In the series of 20 patients (21 joints), the patient and physician satisfaction rate was 81 % at an average follow-up period of 43 months (range 16 to 58 months). Current use of this prosthesis is most reasonable in older patients with painful degenera-tive arthritis of the first metatarsophalangeal joint and minimal joint imbalance. Replacement arthroplasty of the first metatarsopha-langeal joint is possible with a two-component surface endoprosthesis. The results of this exacting surgical technique have been encouraging, but the widespread use of this prosthesis is not now justified in all patients with degenerative arthritis of the first metatarsopha-langeal joint. DESIGN: ANATOMIC AND FUNCTIONAL CONSTRAINTS The metatarsophalangeal joint of the great toe places many constraints on the design of an endo-prosthesis and the technique of insertion. For in-stance, the balance of flexor-extensor and abductor-adductor mechanisms should be left intact as much as possible after insertion of the prosthesis. Unfortu-nately, the insertion of the flexor hallucis brevis is narrow and located on the plantar base of the proximal phalanx. Because the base of this phalanx must be resected during insertion of the prosthesis, the mus-culotendinous balance is easily disrupted. If, however, dissection is done very close to the phalanx base, an intact extension of this tendon's action on the proximal phalanx through a periosteal sleeve can be maintaine