Sequelae of childhood septic arthritis of hip
Total hip replacement may be sought for sequelae of childhood septic arthritis. The issues that the orthopedic surgeon faces are 1) Ill developed socket 2) Proximal migration of poorly developed or destroyed proximal femur. 3) Narrow femoral canal 4) Grade 4 dislocation of femur 4) Abnormal close proximity of femoral vessels and nerve, sciatic nerve. Subtrochanteric shortening femoral osteotomy is necessary. Modular femoral stem is prosthesis of choice.
Hip x rays, CT scan, Femoral angiogram, nerve conduction studies of femoral and sciatic nerves
Prepare proximal femoral metaphysis for S Rom. Insert sleeve, then prepare femoral diaphysis with reamers. Then osteotomize femur below tip of S-Rom. Retract proximal femur anteriorly to visualize true acetabulum. Scar tissue will be seen to occupy the true acetabulum. Mobilize scar tissue by starting at superior end and proceeding inferiorly. Ream medially with small reamer and penetrate medial wall by not more than 25%. Then ream postero superiorly with small reamer. Trial with smallest possible acetabular shell. Insert suitable uncemented cup and fix with screws. Insert liner of choice.
Proceed next to stem. Overlap the stem containing proximal fragment over the distal fragment and mark the excess of bone to be resected in the subtrochanteric area of the distal fragment. Insert the stem into the distal fragment and check reduction. If it is tight, release gluteus medius origin from the superior origin. Insert stem in more anteversion than normal.
Proceed to stem insertion and closure.
Pearls and Pitfalls
Check neurovascular status of femoral and sciatic nerves pre operatively.
Keep vascular surgeon handy. Abnormal position of blood vessels may lead to inadvertent vascular damage and resultant hemorrhage.
Use largest head possible. Insert components in more anteversion than normal to reduce incidence of dislocation.
Use a modular stem with hard on hard bearings. Most patients will be young.
Delay weight bearing to six weeks.
Worsening of neural status