462 THE INFERIOR EXTREMITY 



about i inches beyond the tibial tuberosity. When the skin 

 and fasciae have been elevated and retracted; the vastus lateralis 

 and its tendinous expansion which passes to the lateral border 

 of the patella are exposed, together with the patella and the 

 ligamentum patellae. The joint is then opened by deepening 

 the vertical part of the incision. Freer access is gained by 

 dividing the infra-patellar pad of fat and its synovial covering 

 and by elevating the ligamentum patellae from the tibia. In 

 the child the ligament is freed by removing a slice of cartilage 

 from the tibial tuberosity, but in the adult the tuberosity will 

 require to be chipped off with a chisel. In both cases the 

 periosteum at the distal border of the tuberosity must not be 

 divided, since it serves to retain the tuberosity in position 

 subsequently. Thereafter the patella, together with the 

 quadriceps and the ligamentum patellae, may be rotated through 

 a right angle, and its surfaces can then be reversed by flexing 

 the knee. The whole of the joint cavity is then exposed, and 

 if necessary, excision of the joint can be performed (Fig. 135). 



Excision of the Knee- Joint. When it is decided before 

 the operation that excision of the joint is necessary, a large 

 U-shaped incision gives the best access. The transverse limb 

 lies midway between the patella and the tibial tuberosity, and 

 the vertical limbs ascend immediately in front of the collateral 

 ligaments. This incision is to be recommended because it 

 provides an anterior flap, should the condition of the joint, as 

 revealed by the operation, call for amputation rather than 

 excision. 



The initial incision divides the skin, fascia, and the 

 supra-patellar tendon, and opens into the cavity of the joint, 

 which may be widely exposed by flexing the knee. 



The cruciate ligaments are then removed, and this step 

 enables the surgeon to dissect the synovial membrane from the 

 lateral and medial parts of the posterior ligament. In this 

 situation synovial pouches extend upwards behind the condyles, 

 and, unless they are removed, they may give rise to subsequent 

 recurrence of the disease. 



After resection of the cruciate ligaments, it is impossible to 

 obtain a joint which is both stable and movable, and as stability 

 is of primary importance, osseous ankylosis should be aimed at. 

 This result is obtained by removing the articular cartilage and 

 a layer of bone from the condyles of the femur and tibia. When 

 the disease has originated in the synovial membrane and the 



