Abstract
Introduction: This purpose of this prospective review is to evaluate the 12-year results of a previously unreported collarless, cemented, normalized, straight-backed Omnifit femoral stem with a surface roughness of 30–40 microinches.
Methods: Between January 1986 and June 1991, a single surgeon prospectively implanted 305 consecutive cemented THA’s (275 patients) utilizing second-generation cement technique and a posterolateral exposure. The acetabular component was cemented all-polyethylene (4150 resin), with calcium stearate and gamma sterilized in air. Two independent observers employing a patient administered questionnaire, HSS scores and established radiographic criteria performed clinical and radiographic evaluation. The cumulative survivorship analysis was analyzed in terms of best case and worst case.
Results: The demographics included a mean age of 70 years with 170 females and 105 males and a mean body weight of 154 lbs. The preoperative diagnosis was osteoarthrosis in 260 hips, rheumatoid arthritis in 20, fracture in 13, AVN in 8, Paget’s in 2 and hip dysplasia in 2. The mean HSS score was 37.5 out of 40 at last follow-up. The mean clinical follow-up was 12 years and mean radiographic follow-up was 10 years. The overall projected clinical survival was 95.1% at 15 years (CI +3.4%). The cement mantle was grades A or B in 90% and grade C1 in 10%. Femoral stem alignment was neutral in 53%, valgus in 31% and varus in 16%. Revision THA was performed in 9 hips. Both components were revised in 3 cases (2 infection, 1 recurrent dislocation). Socket revision was performed in 4 cases (1.31%) and femoral component revision in 2 cases (0.65%) due to aseptic loosening.
Discussion: This report demonstrates the excellent results of the collarless, cemented, normalized femoral stem with a surface roughness of 30–40 microinches. Although controversy exists on surface roughness and porosity reduction, meticulous technique in the attainment of a centralized femoral stem with a good cement mantle, provides a reproducible, high quality of function and durability of THA in patients 60 – 80 years of age at 12-year follow-up.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
