High placement of porous-coated acetabular components in complex total hip arthroplasty.

The authors retrospectively evaluated the results of 56 hips in 51 patients with an acetabular deficiency who had a total hip arthroplasty with a porous-coated, cementless acetabular component implanted at a high hip center. Forty-nine cases were revisions and seven were primary operations. The mean height of the hip center was 43 mm above the interteardrop line compared to 14 mm for the anatomic center, threefold higher than normal. In contrast, the mean horizontal locus was reduced compared to normal (33 vs 37 mm for the anatomic center). Sixteen acetabular components were small (46-48 mm o.d.) and eight were miniature (40-44 mm o.d.). Despite superior placement of the acetabular component, 32 limbs were lengthened by the procedure. The mean preoperative Harris hip score was 51 (range, 28-93). At a mean follow-up period of 40 months (range, 24-64 months), the mean Harris hip score was 86 (range, 36-100). In 23 hips no radiolucent lines were present at the interface of the bone to the porous mesh, and 33 hips had a thin (0.5 mm), nonprogressive radiolucent line in one or more zones. No acetabular component had migrated and no problems occurred with the screws. Four hips (3 revisions and 1 primary operation) had a complete radiolucent line on one oblique view of the acetabulum. No acetabular component has been revised for loosening.(ABSTRACT TRUNCATED AT 250 WORDS)