Abstract
It is a well-known fact that total knee arthroplasty is a soft tissue operation. Soft tissue balancing is the key to success in total knee arthroplasty. It is paramount importance to preserve the maximal amount of bone on both the femur and tibial side. In Indian scenario, majority of the patients present relatively late with varus or valgus deformity. Adding to this problem is poor bone quality due to osteoporosis. Our technique of Posterior cruciate ligament (PCL) retaining TKA with tibial end plate resection facilitates soft tissue balancing, preserves PCL and maximizes bone preservation on both tibial and femoral side achieving good results in minimum seven year follow up.
We retrospectively analyzed seven year outcomes of 120 knees (110 patients), mean age was 65 years (range 55 to 75 years), who received contemporary cruciate-retaining prostheses with tibial end plate resection technique. The diagnosis was osteoarthritis in 96%, Rheumatoid arthritis in 2% and posttraumatic arthritis in 2% cases. There were more number of flexible varus knees as compared to flexible valgus knees. All the patients were followed up for minimum of 84 months with average follow up of 96 months. They were followed up at 3mths, 6mths, 1,3,5,7,9 and 10 years. The functional assessment was done using knee society knee and function scores. Radiographic analysis was done to rule out subsidence and aseptic loosening. The statistical significance was assessed using chi square test. Survival analysis was done using the Kaplan Meier analysis with revision taken as the endpoint. The average ROM was 100 degrees preoperatively and 120 degrees at last follow-up. The average knee society knee score improved from 45 points preoperatively to 90 points at last follow-up. The average knee society functional score improved from 48 points preoperatively to 84 points at last follow-up (p<0.05). Radiolucency was observed in 20 knees but all except four were non-progressive lesions smaller than 2 mm. None of the implants were revised for subsidence or aseptic loosening of tibial component.
The technique of PCL retaining total knee arthroplasty with tibial end plate resection in arthritic knees with flexible varus or valgus deformity yields good functional outcome in medium term follow up with relatively low incidence of subsidence of the tibial implant. This technique appears promising for total knee arthroplasty in osteoporotic bones where retaining the strong subchondral bone increases the longevity of the implant.
