Association Between Postoperative Medial-Middle Intercuneiform Joint Widening and Recurrence Rates in Hallux Valgus Treated With Modified Lapidus Procedure

Background: Although an association between intercuneiform (C1-C2) joint instability and the recurrence of hallux valgus (HV) deformity after the modified Lapidus procedure has been suggested, there is currently no radiographic evidence to support it. This study aims to investigate radiographic changes in the C1-C2 joint after the modified Lapidus procedure for HV correction, using weightbearing computed tomography (WBCT). Methods: This retrospective cohort study included 52 feet (50 patients) with HV who underwent modified Lapidus procedure and had preoperative and postoperative WBCT. Patients who had an additional transfixation screw between the first and second ray were excluded. The preoperative and average 6.5 months postoperative C1-C2 distance, C1-C2 angle, and C1-ground angle were measured on coronal multiplanar reconstructed WBCT images. Radiographic parameters between the recurrence group (n = 9) and nonrecurrence group (n = 43) were compared. Recurrence of HV deformity was characterized by a postoperative hallux valgus angle (HVA) greater than 20 degrees. Results: Nine of 52 patients (17.3%) had recurrence of their HV deformity. The recurrence group had greater changes in the C1-C2 distance; the median widening in the recurrence group was 0.7 mm (IQR, 0.6-0.8), whereas the nonrecurrence group was 0.3 mm (IQR, 0.1-0.4, P < .001). Regression analysis showed that increase in the C1-C2 distance were significantly associated with recurrence (odds ratio, 1.79; 95% CI, 1.18-3.77; P = .0015). Although no preoperative imaging parameters were associated with a change in the C1-C2 distance, increasing postoperative sesamoid position ( r = 0.32, P = .022) and HVA ( r = 0.28, P = .046) were correlated with a greater change in the C1-C2 joint gapping. Conclusion: Our study results suggest a possible association between early postoperative widening of the C1-C2 joint and the recurrence of the HV deformity following a modified Lapidus procedure. This raises, but does not answer, the question as to whether the routine stabilization of intercuneiform joint directly or indirectly may help reduce the rate of hallux valgus recurrence when performing the modified Lapidus procedure.