The purpose of this study was to identify subtypes of atraumatic osteoarthritis of the tarsometatarsal joints based on accompanying foot deformities and to determine whether concurrent procedures done for each subtype were effective.
The study included 59 patients (67 feet) with atraumatic tarsometatarsal joint osteoarthritis treated with tarsometatarsal fusion. The average patient age was 60.2 years with 40.6 months followup. Patients were evaluated with radiographs, the American Orthopaedic Foot and Ankle Society (AOFAS) Midfoot Scale, the Foot Function Index, and the Short Form-36 Health Survey Questionnaire (SF-36).
Four main subtypes were identified based on associated foot deformities: pes planovalgus (27), hallux valgus (11), in-situ without deformities (eight), and rockerbottom (five). Plantar-medial closing-wedge resection was used to correct rockerbottom deformity. For pes planovalgus deformity, a medial sliding calcaneal osteotomy was done. Lateral column lengthening with medial sliding calcaneal osteotomy was done for tarsometatarsal osteoarthritis with severe pes planovalgus, and triple arthrodesis was done for rigid pes planovalgus. Tarsometatarsal osteoarthritis with hallux valgus deformity was corrected with the Lapidus procedure. There were 29 complications, most commonly sesamoid pain. The pes planovalgus group showed significant radiographic improvements in four of five parameters measured. AOFAS scores improved from retrospectively assigned preoperative 34.1 points to postoperative 83.9 points. The Foot Function Index showed a high satisfaction rate (86.6%). SF-36 scores averaged 50.6 postoperatively.
When feet with atraumatic tarsometatarsal osteoarthritis are classified into four main categories based on associated deformities, appropriate concurrent procedures can be done with high satisfaction and improved function scores. Pes planovalgus feet, in particular, may benefit from concurrent procedures with improved radiographic measures.