Minimally Invasive Surgery vs Open Approach to First Metatarsophalangeal Joint Arthrodesis: A Comparison of Surgical Outcomes

Category: Midfoot/Forefoot; Other Introduction/Purpose: Minimally invasive surgery (MIS) is becoming increasingly popular among foot and ankle orthopaedic surgeons, as it has been shown to have limited complication rates and faster recovery times. Although there is robust data on MIS to treat hallux valgus, few studies have evaluated the role of MIS for 1st metatarsophalangeal (MTP) fusion to treat hallux rigidus - the most common arthritis of the foot. Hallux rigidus affects 2.5% of the U.S. population over age 50. Given this disease prevalence, it is important to characterize outcomes following MTP fusion procedures to optimize surgical approaches. In this retrospective cohort study, we aim to compare (1) patient-reported pain, (2) rate of successful fusion, and (3) rate of complications between groups who underwent open or MIS 1st MTP arthrodesis. Methods: This retrospective cohort study was conducted by evaluating clinical metrics, surgical outcomes, and radiographic data through chart review of 78 patients (25 male, 53 female), who underwent a 1st MTP fusion procedure at a large urban academic medical center from July 2015 through January 2023. 71 patients had a diagnosis of hallux rigidus, with other common diagnoses including hammertoe (24), hallux valgus (24), additional arthritides (11), and metatarsalgia (11). Two patients were excluded from our analysis due to lack of sufficient orthopaedic follow-up preventing evaluation of joint fusion. Pre- and post-operative pain scores were recorded on a 0-10 scale, though some notes documented subjective experience of pain (e.g., “minimal”). Complications were identified using post-operative clinic notes. The following radiographic data were included: hallux valgus angle, intermetatarsal angle, Coughlin classification, presence of arthritis, pre-operative sesamoid position, fusion construct materials, and success of fusion. Results: Of the 80 1st MTP fusion surgeries (two patients received both left and right foot operations), 51 were open and 29 were minimally invasive. There was no significant difference in the change in pre- to post-operative pain between the two groups (p=0.39). MIS patients had a higher successful fusion rate (100.0%) when compared to open surgery patients (94.1%), though this difference was insignificant (p=0.55). There was no significant difference in overall complication rates between MIS and open surgery groups (p=0.79). However, the MIS patients did not have any cases of deep infection or wound dehiscence and all (5/5) of their complications were related to hardware removal after fusion, whereas half of the complications (5/10) for the open surgery patients were related to infection and wounds. Conclusion: This retrospective analysis of 78 patients treated for hallux rigidus with 1st MTP fusion surgery showed no significant difference in rates of successful fusion and complications among patients who received an MIS procedure compared to an open surgery. There was no difference in patient-reported pain improvement between the two groups. Our main limitation is provider specialization, as only one surgeon in this study performed the MIS cases. Further studies should be done to obtain higher-level evidence to elucidate potential benefits of MIS over open surgery for 1st MTP arthrodesis