Large osteophytes must be removed from the medial margin of the medial femoral condyle and from both margins and roof of the intercondylar notch (Fig. 7.6). Full clearance of the lateral side and apex of the notch must be achieved so as to ensure the ACL is not damaged and that the fixed flexion deformity corrects. Care should be taken while removing osteophytes from the anteromedial corner of the notch because the origin of the PCL can be damaged. The assistant extends and flexes the knee, moving the incision up and down, so that the various osteophytes come into view.
Figure 7.6 Removing medial margin osteophytes.
A narrow chisel (6 mm) is needed to remove the femoral osteophytes from beneath the medial collateral ligament (Fig. 7.7) and from the posterolateral margin of the medial condyle (to make room to insert the saw blade into the intercondylar notch at the next step).
Figure 7.7 Removing femoral osteophytes beneath the medial collateral ligament.
Osteophytes should not be removed from the medial tibia as this may damage the MCL. These osteophytes tend to be removed with the resected tibia.
Osteophytes are removed from the anterior tibia because they interfere with seating of the tibial saw guide. In addition, there is usually an anvil shaped osteophyte anterior to the insertion of the ACL on the tibia. This should be removed.
Large medial patellar osteophytes should be removed to improve access but the odd facet should be retained. If the patella cannot be subluxed laterally, causing difficulty with access, the incision in the capsule and muscle should be extended proximally.