Osteotomy through the bare area of olecranon minimises the damage to articular cartilage in the trans-olecranon approach to the distal humerus. In this study we have identified a reliable and easily reproducible anatomical land mark to make sure that the osteotomy passes through the bare area. Two methods were used to determine the line for the osteotomy, in the first a line from the lateral epicondyle perpendicular to the olecranon and in the second an intra-articular marker was used to determine the osteotomy. In 5 cadavers the osteotomy with lateral epicondylar line as a marker went 2 mm proximal to the bare area. Of the 5 cadavers dissected with a marker passed to the angle of olecranon the osteotomy went through the bare area of olecranon in three specimens and just proximal in the other two. In conclusion a cheveron osteotomy with the base of the chevron on the lateral epicondylar line will be the ideal site to make sure that the osteotomy passes through the bare area of the olecranon.
The Bristol Knee Group has prospectively followed the results of over 500 isolated patellofemoral arthroplasties. Initial experience with the Lubinus prosthesis was disappointing. The main causes of failure were mal-tracking and instability leading to excessive polythene button wear and disease progression in the tibio femoral joint. This experience resulted in the design of a new prosthesis to correct the tracking problems and improve the wear. We have now performed over 425 Avon arthroplasties with a maximum follow-up of 9 years. Survivorship at 5 years and the functional outcome have been reported with 95.8% survivorship, and improved function with Oxford score from 18 to 39 points out of 48. There have been 14 cases with mal-tracking (3%). Several of these cases have required proximal or distal realignment with the Elmslie or Insall procedures. Two knees with patella alta required distalisation of the tibial tubercle. Symptomatic progression of the arthritic disease in the medial or lateral tibio-femoral compartments has occurred in 28 cases (7%) causing recurrent joint pain. Radiographic follow-up has shown a higher rate of disease progression emphasising the importance of careful assessment of patients prior to operation. We have investigated 8 cases of persistent unexplained pain. Analysis of these cases suggests 3 possible causes. An extended anterior cut leading to overstuffing, insufficient external rotation and over sizing of the femoral component leading to medial or lateral retinacular impingement. Six of these cases have been successfully treated by revision of the femoral component leading to dramatic resolution of the symptoms.Introduction
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