Outcomes following 1st metatarsophalangeal joint fusion for failed total joint arthroplasty.

BACKGROUND

Increasing cases of 1st metatarsophalangeal joint (MTPJ) arthroplasty are being offered as an alternative to primary arthrodesis. Few studies analyze outcomes after salvage arthrodesis for failed 1stMTPJ arthroplasty. This study aims to determine the outcomes following conversion arthrodesis for failed total 1st MTPJ replacement.

METHODS

A retrospective study of patients following 1stMTP joint arthrodesis for failed total joint arthroplasty from 2011 to 2024 was performed.

PRIMARY AIM: to assess the union rate, secondary aims: to assess functional outcomes and surgical complications. Union was assessed radiographically. Functional outcomes: determined using the index Manchester-Oxford-Foot Questionnaire (MOxFQ) scores (0-100) postoperatively. Intraoperative and post-operative surgical complications were evaluated.

RESULTS

18 1stMTPJs in 14 patients had arthrodesis for failed total joint replacements. 4 had bilateral arthrodesis at different sittings. Mean age at revision arthrodesis was 57.9 years (48-79years). 13 explanted joints were Toefit-Plus™,5 were Roto-Glide™. Mean time from primary arthroplasty to arthrodesis was 59.9months (11-112months). 17 joints had tricortical iliac crest grafting, one had a sliding metatarsal graft. Mean time to radiographic union was 16.6 weeks (SD 6.0; 95% CI 13.7-19.4; range 8-28weeks). Median postoperative MOxFQ score was 5.5 (IQR 3.5-12.5; range 0-34.4). 1 patient (5.6%) had symptomatic nonunion, 2 (11.1%) had malunion and 2 (11.1%) had symptomatic hardware. One patient had lateral femoral cutaneous nerve injury from anterior iliac crest bone graft harvest.

CONCLUSION

1stMTPJ arthrodesis after failed total joint replacement is a complex procedure due to bone loss. The use of structural iliac crest bone graft reduces the nonunion rates to be closer to those of literature reports for primary arthrodesis. There are favorable functional outcomes following this procedure with relatively high surgical complications and longer time to radiographic union compared to that of primary arthrodesis. Further highly powered comparative studies may better guide the management of failed total 1stMTPj arthroplasty.

LEVEL OF EVIDENCE: 4(retrospective case series).