O3476 EARLY OUTCOMES OF CEMENTLESS STEMS IN TOTAL HIP ARTHROPLASTY

Abstract

Aims: This study reports early outcome data from a contemporary tapered cementless stem. Methods: Fifty patients (55 hips) underwent THA and received cement-less femoral and acetabular components (Encore Medical, Austin, TX). All stems were collarless with a 3-dimensional wedge geometry manufactured from titanium alloy with a proximal full circumferential titanium porous coating. There were 19 females and 31 males with an average age and weight of 63(31–81) years and 86(46–114)kg, respectively. Initial diagnosis was osteoarthritis (76%), osteonecrosis (15%), congenital dysplasia (5%), rheumatoid arthritis (2%) and trauma (2%). Patients were followed prospectively and Harris Hip Scores were recorded. Pre-operative, immediate postoperative, and annual radiographs were evaluated for stem and cup position, component migration, and evidence of radiolucent lines and bony adaptation. Results: The average length of follow-up was 2.0±0.4(1.5–3.1) years. There were no cup or stem revisions at this early follow-up interval. The average Harris Hip Score was 95 points (range, 63 to 100). Average cup inclination was 53¡(38¡–65¡). Radiolucent lines around the acetabular cup were infrequent (7%) and were less than 1 mm in width. Stem subsidence was noted on 10 (18%) stems, consistent with the collarless stem geometry. Some medial calcar atrophy was noted in 78% of the hips. Six (11%) stems had distal radiolucent lines > 2 mm in width. One (2%) stem had pedestal formation at the distal stem. Conclusions: Excellent midterm outcomes have been reported for tapered cementless stems with proximal circumferential porous coating. Radiolucent lines in the distal stem zones and mild medial calcar atrophy have not been associated with inferior outcomes up to 10 years.