Abstract
Introduction and Aims: Difficult primary and revision total knee arthroplasty (TKA) with constrained knee systems is becoming more common. Modular systems are critical to success. A review of 457 consecutive cases with a single knee system for difficult primary and revision TKA provides an algorithm for good results.
Method: Between July 1992 and December 2000, 457 consecutive TKA were performed at a single institution using a posterior-stabilised constrained (PSC) system. Ninety-seven cases were primary with ligamentous instability and 360 were revision cases with bone loss and instability. Sixty-two patients died during follow-up, seven were lost to follow-up.
Results: Follow-up averaged 2.5 years. Pre-operative Knee Society (KSS) and Hospital for Special Surgery (HSS) scores averaged 47.3 and 60.0 respectively, and improved to 79.0 and 75.0 (p< 0.001). Range of motion improved significantly (p< 0.001). Incidence of manipulation was 9.4 percent. Infection necessitated debridement in 4.6 percent of cases. Extensor mechanism complications occurred in 2.2 percent. Excision of the patellar component without reinsertion was highest risk. There was a 2.2 percent aseptic loosening rate and 3.0 percent failure for instability.
Conclusion: The authors describe an algorithm for long-term success using a PSC modular knee system based upon critical review of radiographic and clinical outcomes. Methods for achieving stability and fixation affect results. Appropriate augmentation for femoral and tibial deficits re-establishes the joint line and provides excellent range of motion. A step-wise approach to the patella provides durable results. Predictors of success including alignment, the joint line, managing bone loss, fixation, and extensor mechanism are reviewed.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
