← Evidence libraryNJR stemmed MoM failure
Failure rates of stemmed metal-on-metal hip replacements: analysis of data from the National Joint Registry of England and Wales.
Smith AJ, Dieppe P, Vernon K, et al. Lancet (London, England) 2012 · PMID 22417410 · doi:10.1016/s0140-6736(12)60353-5
Registry studyPrognosisHip arthroplastyCitation checked
- Question
- How do revision rates of stemmed metal-on-metal total hip replacements compare with other bearing surfaces?
- Design
- Analysis of the National Joint Registry of England and Wales.
- Patients
- Patients with primary stemmed total hip replacements recorded in the NJR, including metal-on-metal bearings.
- Intervention
- Stemmed metal-on-metal bearings
- Comparison
- Metal-on-polyethylene and ceramic bearings
- Primary outcome
- Implant revision
- Key result
- Stemmed metal-on-metal hips had significantly poorer survival than other bearings, with larger heads failing earlier, whereas larger heads improved survival for ceramic-on-ceramic bearings; younger women with large metal-on-metal heads had particularly high revision rates.
- Limitations
- Registry data cannot fully adjust for confounding by surgeon, implant design or case mix, and revision is an imperfect proxy for failure.
- Impact on practice
- Contributed to the near abandonment of metal-on-metal THR and to MHRA surveillance of patients with these implants, including blood metal ion testing.