High Prevalence of Degenerative Changes at the Metatarsal Head Sesamoid Articulation Found During Hallux Valgus Correction Surgery

CATEGORY: Bunion INTRODUCTION/PURPOSE: Despite absence of complications and a restoration of normal hallux alignment, some patients have suboptimal outcomes from hallux valgus correction surgery. One risk factor for persistent pain may be the presence of arthritic changes at the metatarsal head articulation with the sesamoids, an area not easily assessed with standard preoperative radiographs. In this study, we prospectively evaluated the metatarsal head for degenerative changes during hallux valgus correction surgery and identified preoperative risk factors associated with these changes. METHODS: We prospectively evaluated 200 feet in 196 patients who underwent hallux valgus surgery intraoperatively for the pattern and severity of arthritic changes at the metatarsal head. Intraoperatively, the first metatarsophalangeal and sesamoid metatarsal joint were assessed for arthritic changes. The articular surface of the metatarsal head was divided into zones 1-6 (Figure 1). Cartilage loss in each zone was graded from 0-2 based on a novel grading system, with a score of 0 representing the absence of arthritis. A score of 1 indicated fissures without exposed bone, and a score of 2 represented degenerative changes to the level of exposed bone. Mann-Whitney U testing was implemented to compare differences in arthritic scores between preoperative deformity groups. Spearman’s correlation test was used to determine the association between age and preoperative deformity with the severity of degenerative changes. RESULTS: One-hundred two out of 200 feet (51%) assessed had severe arthritic changes at the plantar medial aspect of the metatarsal head, and 40% (80/200) at the plantar lateral aspect. The mean preoperative hallux valgus and intermetatarsal angles were 29.6 ± 8.5 (range, 9.8-55.3) and 14.2 ± 3.3 (range, 6.6-25.9), respectively. Those presenting with an intermetatarsal angle (IMA) >/= 14 degrees had a significantly higher level of arthritis when compared to those presenting with an IMA < 14 degrees (p < 0.001). No difference in arthritis scores was found for HVA. Age was found to have a strong and significant (p < 0.001) correlation with zone 5, zone 6, total plantar zone, and total arthritis scores. CONCLUSION: The high prevalence of arthritic changes at the metatarsal head articulation with the sesamoids may be partially responsible for suboptimal outcome following hallux valgus correction surgery. Since these changes were associated with greater age and preoperative deformity, operating earlier in the pathology of hallux valgus may be of benefit.