Objective: Correction of splayfoot deformity through reduction of the increased first intermetatarsal angle by a proximal open-wedge osteotomy.
Indications: Splayfoot deformity with a first intermetatarsal angle > 14 degrees and hallux valgus deformity in younger patients. Splayfoot deformities with a short first metatarsal.
Contraindications: Degenerative changes in the first metatarsophalangeal joint. Contractures of the first metatarsophalangeal joint. Relative: overlength of the first metatarsal. Relative: lateral tilt of the articular cartilage surface of the first metatarsal head.
Surgical technique: Proximal metatarsal osteotomy approximately 10 mm distal of the first tarsometatarsal joint with preservation of the lateral cortex. Careful manual opening of the osteotomy to avoid a fracture of the lateral cortex. Fixation of the osteotomy with an interlocking plate. Filling of the defect with cancellous bone. Distal soft-tissue procedure.
Postoperative management: Postoperative hallux shoe for 6 weeks. Partial weight bearing (20 kg) for 2 weeks, afterwards full weight bearing. Mobilization of the first metatarsophalangeal joint. Full weight bearing in comfortable shoes after appropriate bony healing has occurred radiologically. Sports with a high impact on the foot is allowed after 12 weeks. Orthotics are prescribed, if some pain remains or associated pathologies require external support.
Results: In a consecutive series of 35 patients, the first intermetatarsal angle could be reduced to normal values (6.8 degrees , standard deviation 1.3 degrees ). The open-wedge osteotomy resulted in a slight lengthening of the first metatarsal (1-2 mm). In one patient local wound healing problems had to be treated with oral antibiotics. Operative revision was not necessary in any case. Implant failure or nonunion was not observed. One plate was removed because of local subcutaneous irritation.