Abstract
The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive any payments or make agreements to provide such benefit from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other non profit organization with which the authors are affiliated or associated.
Background: We observed early osteolysis and loosening of the rough surface-cement stem with a second generation metal-on-metal articulation. This study was to investigate the possible etiologic role of stem loosening and osteolysis by examination of the surface of the rough blast cement and related periprosthetic tissues that have been retrieved at revision.
Methods: We retrospectively analyzed 39 hips (37 patients) with use of metasul metal-on-metal total hip arthroplasty. Of the femoral stem, rough surface-cement stem used in 18 hips and cementless Ti-alloy stem in 21 hips. The mean duration of follow-up was 10.2 years. Of these eight rough blast cement stem were revised, seven in loosening and one in recurrent dislocation. By using energy disperse spectroscope and back scattered electron image, histologic studies were performed to the samples of periprosthetic tissues. Skin patch tests for metal hypersensitivity were done to select patients.
Results: All of cementless stems and cups showed excellent results at the last follow-up. However, eight cement hips were revised. Light microscopy showed polishing effect on retrieval femoral stem affected by the rotational force. EDS and BSE image revealed that there were abundant cement and related metal particles with size of 5-10μm. However there were few metal particles and had greater size (20–100μm) in periprosthetic tissues. Histologic finding shows perivascular infiltration of lymphocytes and accumulation of macrophages No relation was found between skin patch test and loosening.
Conclusion: These findings raise the possibility that early osteolysis and loosening in patients with metal-on-metal hip replacement were associated with rough blast surface cement stem. These mixed particles such as Fe and Zr maybe trigger lymphocytic reactivity suggestive delayed type hypersensitive reaction. This study suggests that cement stem which have rough blasted surface should be considered in metal-on-metal total hip arthroplasty.
Level of Evidence: Therapeutic level III-1(case-control study). See instructions to authors for a complete description of level of evidence.
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