Metal-on-Metal total hip replacement: what does the literature say?
Second-generation metal-on-metal (M/M) total hip replacements were introduced into clinical use in the late 1980s and demonstrate equivalent survivorship to conventional metal-on-polyethylene prostheses. Wear rates are comparable to those of first-generation designs that survived for a long time in the body. Biological effects from metal ions remain a concern. Patients with both first- and second-generation M/M hips have higher levels of cobalt and chromium in their blood and urine than either patients with metal-on-polyethylene devices or unoperated patients. Concerns include the potential for acquired hypersensitivity, mutagenicity, and carcinogenicity. However, reports of proven adverse effects are scant. Prospective, randomized trials with follow-up in excess of 15 years will be needed to differentiate between the performance and effects of M/M and other bearing combinations. Key words: totalhip arthroplasty, metal-on-metal, wear, biological effects, clinical results.
Dumbleton
John H
JH
Consultancy in Medical Devices, Biomaterials, and Technology Assessment, Ridgewood, New Jersey, USA.
Manley
Michael T
MT
D000485:Allergens / Q000032:analysis; D019644:Arthroplasty, Replacement, Hip; D002273:Carcinogens / Q000032:analysis; D002857:Chromium / Q000097:blood / Q000652:urine; D003035:Cobalt / Q000097:blood / Q000652:urine; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D009153:Mutagens / Q000032:analysis; D011474:Prosthesis Design; D011475:Prosthesis Failure
D000485:Allergens; D002273:Carcinogens; D009153:Mutagens; D002857:Chromium; D003035:Cobalt