TOTAL HIP-ARTHROPLASTY - CONCERNS WITH EXTENSIVELY POROUS-COATED FEMORAL COMPONENTS

A series of 507 consecutive, unselected cementless hip arthroplasties performed by one surgeon was reviewed to address specifically potentia l concerns with the use of extensively coated femoral components, incl uding the frequency and nature of reoperation, thigh pain, component s tability, osteolysis, and stress shielding. Excluding hips in patients who had died or were lost to followup, there were 426 hips with minim um 5-year followup. The overall femoral reoperation rate of 2.6% (13 c ases) included seven for failure of fixation and six for osteolysis. O f the unrevised cases, 96% of the femoral components showed radiograph ic bone ingrowth, and 3.7% showed a stable fibrous pattern. Fixation d id not deteriorate with time. A 2.9 % incidence of activity limiting t high pain did affect clinical outcome (limp, ambulation tolerance, sup port), but there were no clinical or radiographic predisposing variabl es. There was no detectable femoral osteolysis in 88.3% of cases. The remainder had lesions confined to Gruen Zones 1 and 7, suggesting that circumferential extensive coating was protective against distal osteo lysis. Although osteolysis did not affect component stability, in six cases it did result in pathologic trochanteric fracture, contributing to the frequency of reoperation. Stress shielding was common (25%) and was related to older patients and the use of larger diameter stems (> 15 mm), but did not predispose to thigh pain, loosening, osteolysis, or an inferior clinical result. These results documented the clinical and radiographic success in the use of extensively coated cementless f emoral components. Debris generation from wear and resulting osteolysi s remain significant concerns in a hip arthroplasty with this design a s with many others. However, concerns about the high incidence of reop eration, thigh pain, component instability, or stress shielding are no t supported by this study.