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93.5 Arthroscopy and magnetic resonance imaging have both brought an increase in diagnostic accuracy and to our understanding of certain patterns of injury. Management of knee injuries has also changed markedly over the years with the introduction of these techniques and investigations. Surgery has become more refined, more intervention is undertaken these days and this course of action alters the prognosis. Further follow-up studies in the future of the results of treatment will add to our knowledge.

94 ANATOMY

94.1 The anterior compartment The knee joint may be considered to have three distinct and partially separated compartments, see Figures 24A and B. The anterior [front] or patello-femoral compartment is the patella articulation with the femoral groove, see Figure 24A. The patella articulates with the femoral groove to about 90 degrees of flexion after which it comes into articulation with corresponding parts of the femoral condyles. The patello-femoral joint is noted for its change in contact with the position of the patella and femur during flexion. Contact and dye studies have shown the contact area is never greater than one third of the patella articular surface. The maximum area being at approximately 45 degrees of flexion. The contact area on the patella moves up the patella with flexion, in full extension the contact area is mainly on the lower part of the patella, at 45 degrees in the mid portion of the patella and at 90 degrees in the upper portion of the patella.

94.2 The medial and lateral compartments These are made up of the appropriate femoral condyle and tibial plateau with the intervening meniscus that covers approximately two thirds of the articular surface of the tibial plateau. The femoral condyles differ in shape and dimension offering different areas to the patella and the tibial plateau, see Figure 24B.