Modified Scarf Osteotomy with Medial Capsular Interposition in Great Toe and Metatarsal Shortening Offset Osteotomy in Lesser Toes for Rheumatoid Deformity

Overview Introduction Modified Scarf osteotomy combined with metatarsal shortening offset osteotomy of the lesser toes provides stable forefoot realignment with preservation of the motion of the first metatarsophalangeal (MTP) joint. Indications & Contraindications Step 1: Preoperative Planning On a standing anteroposterior radiograph, plan the resection of the first metatarsal as the amount equal to the overlap of the first metatarsal and the base of the proximal phalanx, and plan to resect enough length of the lesser metatarsals to allow reduction of the MTP joints while keeping these metatarsals longer than the first. Step 2: Operating Room Setup (Fig.2) With the patient supine, and a fluoroscope in place to later check alignment and correction, ensure that full knee joint flexion is possible so that the foot can be placed parallel to the operating table. Step 3: Incisions (Fig. 3) Make the incisions. Step 4: Approach Approach the lesser toes through the lateral 2 dorsal toe incisions and the great toe through the dorsal first web space incision. Step 5: Osteotomy and Reduction Resect a sufficient amount of each lesser metatarsal neck to allow reduction of the respective MTP joint (Fig. 5-A); to correct the hallux valgus deformity, perform sufficient shortening and translation of the first metatarsal shaft through a horizontal longitudinal osteotomy (Fig. 5-B). Step 6: Fixation Lock the distal fragment (metatarsal head) of the lesser metatarsals into 3-mm-deep grooves in the cortical bone of the proximal fragment and then secure it to the proximal fragment with a 1.2-mm Kirschner wire (Fig. 6-A); shift the distal bone fragment of the first metatarsal laterally and securely fix it with screws (Fig. 6-B). Step 7: Medial Capsular Interposition and Closure After correction of the hallux valgus deformity using the modified Scarf osteotomy, interpose the 10-mm-wide capsular flap into the first MTP joint (Fig. 7). Results In our series of 76 cases in 60 patients, sufficient reduction of the hallux valgus deformity was achieved consistently even in cases with severe destruction (Larsen grade 4 or 5) of the first MTP joint due to rheumatoid arthritis2. Pitfalls & Challenges
Background: Arthrodesis of the first metatarsophalangeal (MTP) joint has been recommended for severe hallux valgus deformity in patients with rheumatoid arthritis. We developed an alternative procedure that preserves motion of the first MTP joint while restoring alignment and balance to the forefoot. This procedure was shown to be effective in a series of 60 patients with a 3-year follow-up. Description: We perform a modified Scarf osteotomy, with the longitudinal first metatarsal cut parallel to the sole of the foot and with shortening of the metatarsal to realign the first ray. This is combined with an interpositional capsular arthroplasty of the first MTP joint and shortening offset osteotomies of the lesser metatarsals. Alternatives: Alternatives include arthrodesis of the first MTP joint combined with resection arthroplasty of the lesser MTP joints, or of all 5 MTP joints, or perhaps interpositional (total) joint arthroplasty for severe rheumatoid forefoot deformity/destruction. Rationale: The purpose of the modified Scarf osteotomy is preservation of motion of the first MTP joint and protection against destruction of the rheumatoid joint. The metatarsal shortening offset osteotomy provides rigid stabilization at the site of osteotomy after dynamic correction to make the transverse arch.