Canine porous resurfacing hip arthroplasty. Long-term results

Long-term experimental data support the hypothesis that biologic bone ingrowth into porous surfaces in a hip-resurfacing model is a viable alternative to stem-type porous implants. Ingrowth of bone was demonstrated in long-term canine arthroplasty. The components were well fixed and stable at the time of sacrifice, although ingrowth occurred to varying degrees. The ingrowth and quality of remodeling was influenced by stress. Dislocations were overcome by a change in surgical technique. Loosening and neck fractures were associated with insufficient stability at operation or to component impingement (prevented by modifications of design). The formation of metal debris-filled cysts is a concern and appeared to be associated with the poor quality of porous sintering and possibly abrasion. The effects of increased surface area of the porous components such as increased corrosion products on biologic compatibility are still not well defined and require further research and longer follow-up examination.