Extensor mechanism disruption following primary and revision total knee arthroplasty: a systematic review and meta-analysis.

BACKGROUND

Extensor mechanism disruption (EMD) following total knee arthroplasty (TKA) is a rare but debilitating complication, with an incidence ranging from 0.1 to 2.5%. This condition requires surgical management, either by direct repair or reconstruction using various graft options. Existing literature reports inconsistent outcomes and high complication rates.

METHODS

A comprehensive search of MEDLINE and Cochrane database (1990-2024) identified studies on EMD management. Studies of Evidence Levels I-IV with a minimum 6 months follow-up, and clear reporting of interventions for EMD were analysed. Data extraction focused on patient demographics, treatment options, and outcomes such as failure rates, complications, extensor lag, range of motion, and ambulation status. Quality appraisal was conducted using the Joanna Briggs Institute (JBI) checklist for non-randomized studies.

RESULTS

A total of 32 studies (655 reconstruction cases, 119 repair cases) were included. Reconstruction options using allografts and synthetic mesh showed comparable failure rates (~ 32%). Direct repairs of quadriceps and patellar tendons demonstrated a failure rate of 33.9% and 63% respectively. Autograft reconstruction options reported no failures but were underrepresented. Extensor lag varied across groups, with autografts demonstrating the least extensor lag (5°). Ambulation status improved postoperatively in successful cases. Complications such as periprosthetic joint infections (PJI) were prevalent in failed cases (39-44%).

CONCLUSION

EMD after TKA, managed with reconstruction using allografts or synthetic mesh yielded similar outcomes. Autografts and medial gastrocnemius flaps showed better outcomes in a limited cohort. Larger prospective studies, are needed to address the heterogeneity in outcomes and reporting.

LEVEL OF EVIDENCE: Level IV.