The aim of this study is to assess the extent of osteolysis around a TKR which would then help in effective planning of revision surgery. Osteolysis around a TKR can be difficult to identify in plain radiographs because this typically occurs in low radiodensity cancellous bone of distal femur and proximal tibia. These can often look innocuous and benign allowing the surgeon to fall into a false sense of security. We discuss the use of 3 dimensional CT scan in 7 cases with pre revision initially unsuspected massive osteolysis and its usefulness in planning appropriate implant and/or bone grafting technique in revision surgery. 6/7 knees had a primary cruciate retaining knee implant and the mean time to revision surgery was 11 years and 8 months Based on our pre operative CT assessment we were able to plan and effectively undertake 3 custom built prosthesis and 4 stemmed revision implants along with the use of adjunct bone additives including allograft. On the basis of this experience we would recommend the routine use of a 3D CT scan in preoperatively assessing a revision TKR and would caution the appearance particularly of the ‘posterior femoral bubble’ as it often belies a large osteolytic cavity.
Chronic medial collateral ligament (MCL) instability is an unusual clinical problem. Due to the unsatisfactory results of advancement procedures or reconstruction using autologous techniques we have devised a new technique using a non-irradiated tendo achilles allograft construct. Three patients are presented who had symptomatic MCL insufficiency. The laxity was demonstrated clinically (all grade 3) and radiologically using valgus stress views. The tendo achilles was fashioned into a triangular composite graft consisting of a bone plug (30 x 10 mm) and the tendon. The bone plug was attached to the femur at the anatomical insertion of the MCL using an interference screw and the tendon on the tibia using a multiple suture anchor technique. The rehabilitation programme consisted of immediate mobilisation and the use of a brace for twelve weeks. At follow-up (average 12 months) all patients were asymptomatic, had a full range of movements, no increased clinical laxity and no increased radiological laxity to a valgus force at 25 degrees of flexion when compared to the other side. We conclude that this is an effective technique in the treatment of chronic symptomatic MCL laxity.
