HIGH HIP CENTER IN REVISION ARTHROPLASTY

What is the effect of superior placement of the acetabulum in complex hip reconstruction? Twenty-two patients (23 cases) had revision hip ar throplasty with superiorly placed porous-coated components without bon e-grafts. Cemented femoral components were used in 21 cases and ingrow th components in 2. The average vertical height (corrected for magnifi cation) was 36.8 mm from the interteardrop line, compared to a contral ateral normal height of 12.1 mm. Three patients were deceased. The rem aining 19 patients (20 hips) had a minimum 2-year follow-up period (av erage, 35 months). Fourteen hips had two or more previous surgeries. S even acetabular components had thin (<1 mm), nonprogressive, incomplet e radiolucent lines. One acetabulum had a complete 1 mm radiolucent li ne in an asymptomatic patient. The remaining 12 acetabular components had no evidence of radiolucent lines and none of the acetabular compon ents migrated. One hip with a cemented femoral component had evidence of possible loosening. Two cemented femoral components had evidence of definite loosening, one with minimal clinical symptoms and the other was revised to a long stem at 14 months after revision. Of the two ing rown femoral components, one had initial subsidence of 1.5 cm and both had thigh pain. All other patients had improved from their preoperati ve status; however, 4 of 20 hips had moderate to severe pain. Superior cup position did not result in concomitant lateral position. With a s hort term follow-up period however, vertical displacement alone result ed in high loosening rates, with 25% for the femur and 5% for the acet abulum.