Synthetic Mesh Allograft Reconstruction for Extensor Mechanism Insufficiency After Knee Arthroplasty

Extensor mechanism (EM) insufficiency after knee arthroplasty is a rare but devastating complication resulting in severe disability. To date, primary repair and allograft reconstructive options have produced suboptimal results. A synthetic mesh allograft reconstruction technique has recently been introduced with promising outcomes. A retrospective chart review was performed to identify all patients who experienced EM failure after total or unicompartmental knee arthroplasty and subsequently underwent synthetic mesh EM reconstruction using a previously described technique. Patient demographics, pre- and postoperative knee range of motion and residual extensor lag, pre- and postoperative pain and functional outcome scores, and complications were extracted during the chart review. Twelve patients met inclusion criteria: 3 with patellar tendon and 9 with quadriceps tendon defects. At mean follow-up of 27.0 months, all patients were ambulatory, with a mean residual extensor lag of 12.9° (range, 0°-30°). Mean visual analog scale pain score decreased significantly after EM reconstruction: 4.6±2.3 (range, 1-8) preoperatively vs 1.8±2.4 (range, 0-7) postoperatively (P=.01). The mean Knee Society knee score improved from 41.5±11.1 (range, 21-57) preoperatively to 79.5±13.8 (range, 54-90) postoperatively (P<.0001). The mean Knee Society function score improved from 14.6±12.3 (range, 0-40) preoperatively to 64.2±27.1 (range, 5-95) postoperatively (P<.0001). One clinical failure occurred as a result of prosthetic joint infection. Synthetic mesh EM reconstruction effectively restores knee function for a variety of EM deficiencies following knee arthroplasty. [Orthopedics. 2019; 42(4):e385-e390.].