Background: Surgical correction of hallux valgus deformities often results in decreased first metatarsophalangeal joint (MTPJ) range of motion. Loss of motion has been shown to affect patient satisfaction. The purpose of this study was to evaluate the immediate change in MTPJ range of motion that occurs after a distal soft-tissue reconstruction (DSTR) and proximal metatarsal osteotomy (PMO).
Methods: DSTR and PMO were done on 16 below-knee cadaver specimens with clinically apparent hallux valgus deformities. Two examiners assessed preoperative and postoperative dorsiflexion (DF), plantarflexion (PF), and the total range of motion of the first MTPJ. The hallux valgus angle (HVA) and 1-2 intermetatarsal angle (1-2 IMA) were measured on simulated weightbearing radiographs before and after operative correction. Changes in motion were analyzed and correlated with the angular measurements.
Results: The mean total range of motion preoperatively was 85.4 degrees (DF 70.5 degrees, PF 14.9 degrees) and significantly decreased (p < 0.005) 23.2 degrees to a postoperative value of 62.2 degrees (DF 47.9 degrees, PF 14.3 degrees). There was a significant (p < 0.005) decrease in DF (22.6 degrees) with the operative correction, but the loss of PF (0.6 degrees) was not significant (p = 0.7). There was no correlation between the magnitude of correction (HVA, 1-2 IMA) and the change in PF, DF, or total motion.
Conclusions: Correction of a hallux valgus deformity with a DSTR and PMO is associated with an immediate loss of range of motion that primarily affects the DF arc of the first MTPJ. The selective loss of DF may be related to a nonisometric capsular repair or tight intrinsic musculature, although there was no correlation with the magnitude of angular correction. The immediate decrease in motion observed in this cadaver study underscores the importance of early postoperative joint mobilization to prevent long-term stiffness after bunion surgery.