RADIOGRAPHIC STABILITY IN CEMENTLESS CUP PLACED AT HIGH HIP CENTER WITH OR WITHOUT SCREWS FOR SUBLUXATED HIPS – PROSPECTIVE COMPARATIVE STUDY FOR TEN YEARS FOLLOW-UP

Purpose: There is no report concerning about long-term comparison result of high placed cementless cup stability with or without screws for developmental dysplasia of the hip. The aim of this study was to ascertain whether or not there are any differences in high placed cementless cup stability with or without screws at the mean 10-year (6–14) follow-up period.Method: We divided 109 hip-cases who underwent identical cementless total hip arthoplasty system (Mallory – Head : Biomet Inc.) to two groups: 57 cups with screw (screw group) and 52 cups without screw (no screw group). No case in both group underwent bulk bone graft for acetabular roof. Radiographic signs of cup instability were defined as the development of radiolucent line (> 2mm) or migration (> 4mm). Degree of subluxation by Crowe classification, cup size and cup abduction angle were also measured.Results: In both groups, there was no significant difference in terms of degree of subluxation (each grade’s %) (screw vs no screw = I (68, 73), II (...