THE HIP- JOINT 433 



to the greater trochanter, and is in the direction of the fibres 

 of the glutseus maximus. In its lower half the incision is carried 

 vertically across the greater trochanter, splitting the ilio-tibial 

 tract. The wound is deepened through the, glutseus maximus, 

 above and below, and it opens into the bursa between the 

 tendon of the muscle and the greater trochanter. A large 

 angular flap, consisting of skin, fasciae, and the glutseus maximus, 

 can now be turned medially, and this exposes the posterior 

 border of the glutaeus medius and the piriformis. When a 

 posterior dislocation has occurred, the head of the femur is 

 found between these two muscles. 



Since the operation is usually performed in children, the 

 epiphysis of the greater trochanter is still partly cartilaginous, 

 and this simplifies the next step, which consists in turning 

 forwards the insertion of the glutaeus medius. The oblique 

 insertion of the muscle (p. 416) is removed along with its peri- 

 osteum and a thin layer of cartilage, and the insertions of the 

 obturator internus and piriformis are treated in a similar way, 

 but they are turned backwards. When these steps have been 

 carried out, the trochanteric fossa, the neck of the femur, the 

 head, if present, and the remains of the dorsal aspect of the 

 capsule are all exposed. 



The capsule is then split in its long axis, and the neck of the 

 femur is divided at its distal end and removed. The condition 

 of the acetabulum and the synovial membrane can then be 

 explored satisfactorily and dealt with. The greater trochanter 

 is brought to the surface and is trimmed to fit the acetabulum. 

 It is then implanted into the latter at an angle corresponding 

 to that of the original neck, and, in order that this position may 

 be maintained, an assistant keeps the limb in the required 

 degree of abduction until the operation is completed and the 

 special abduction splint can be applied. The remains of the 

 capsule and the tendons which were removed are now stitched 

 together over the trochanter, and the split glutseus maximus is 

 sutured. A gauze drain may be passed down to the neighbour- 

 hood of the joint, but no tube is necessary, because, as the 

 acetabulum is now occupied by the trochanter, there is no space 

 to drain. 



This operation aims at obtaining an ankylosed and therefore 

 a stable joint, which is the first essential. When the limb has 

 been kept in a plaster case for a year and firm bony union has 

 occurred, the child is allowed to walk. In order to bring the 



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