Abstract
Complications involving the knee extensor mechanism occur in 1% to 12% of patients following total knee arthroplasty (TKA), and have negative effects on patient outcomes. While multiple reconstruction options have been described for complete disruption of the extensor mechanism, the results in patients with a prior TKA are inferior to those in patients without a TKA, and frequently have required the use of allograft tendon grafts which can attenuate and stretch over time. However, encouraging results have been reported by Browne and Hanssen in treatment of patellar tendon disruption with the use of a synthetic mesh (knitted monofilament polypropylene). In this technique, a synthetic graft is created by folding a 10 × 14 inch sheet of mesh and securing it with non-absorbable sutures. A burr is then used to create a trough in the anterior aspect of the tibia to accept the mesh graft. The graft is inserted into the trough and secured with cement. After the cement cures, a transfixion screw with a washer is placed. A portal is subsequently created in the soft tissues lateral patellar tendon remnants to allow delivery of the graft from deep to superficial. The patella and quadriceps tendon are mobilised, and the graft is secured with sutures to the lateral retinaculum, vastus lateralis, and quadriceps tendon. The vastus medialis is then mobilised and brought in a pants-over-vest manner over the mesh graft, and secured with additional sutures. Finally, the distal arthrotomy is closed tightly to completely cover the mesh graft with host tissue. In their series, Browne and Hanssen noted that 9 of 13 patients achieved an extensor lag of <10 degrees with preserved knee flexion and significant improvements in the mean Knee Society scores for pain and function. A similar modified method has been used at our institution for chronic quadriceps tendon disruptions as well. The reconstructions have shown less of a tendency to late attenuation, stretch and recurrent extensor lag beyond two years compared to our experience with tendon allograft reconstructions and remains our procedure of choice at our institution for the majority of these challenging problems.
