Mid-term outcomes of uncemented or cemented arthroplasty revision following metal-on-metal total hip arthroplasty failure: a retrospective observational study

Long-term Follow-up on Revisions of a Recalled Large Head Metal-on-metal Hip Prosthesis: A Single Surgeon Series

Background

In 2010, a recall was issued for a specific monoblock large head metal-on-metal (MoM) hip prosthesis due to short-term revision rates of 12%-13% (articular surface replacement, DePuy Orthopaedics, Inc., Warsaw, IN). High complication, infection, and rerevision rates for revised MoM implants have been reported. The purpose of the study is to report long-term outcomes and trend metal ion levels of this recalled MoM prosthesis from a single surgeon series.

Methods

Retrospective chart review was performed on all patients that underwent revision of large MoM hip replacements between 2010 and 2015. Pre- and post-revision Harris Hip Score (HHS), cup abduction angles, anteversion angles, and cup sizes were compared. Survivorship and HHS were the primary outcomes measured; serum cobalt and chromium levels were secondary outcomes. Multivariate linear regression was used to examine the correlation between prerevision serum metal ion levels and HHS.

Results

A total of 24 hips (21 patients) met inclusion criteria. Mean time to revision was 4.12 years ± 1.1. Mean follow-up was 10.0 years (7-11.9 years). Mean HHS increased significantly after revision from 48.5 to 89.5 (P < .001). Higher prerevision cobalt levels were correlated with lower prerevision HHS (cobalt R = 0.25; chromium R = 0.3160). There was no correlation with prerevision cobalt (P = .2671) or chromium (P = .3160) with postrevision HHS. Most recent metal ion testing revealed a significant decrease in both cobalt (P = .0084) and chromium (P = .0115). Survival rate is 100%.

Conclusions

Our study showed excellent survivorship and outcomes at 10 years. There were no failures for any reason including infection. This differs from previous studies and confirms excellent long-term results are possible with revision of this recalled MoM implant.

Favourable clinical outcomes following cemented arthroplasty after metal-on-metal total hip replacement: a retrospective study with a mean follow-up of 10 years

BACKGROUND

Given the unexpected high rate of failure following metal-on-metal total hip replacement (MoM-THR), it is expected that more MoM-THR patients will experience revision. The long-term outcomes regarding the primary MoM-THR revised to cemented THR (CTHR) remain controversial. The purpose of this retrospective review was to evaluate the long-term outcomes of patients who underwent conversion from MoM-THR to CTHR.

METHODS

A total of 220 patients (220 hips) who underwent a conversion of primary MoM-THR to CTHR from March 2006 to October 2016 were retrospectively reviewed. The primary outcomes were the functional outcomes assessed using the Harris hip scores (HHS) and major radiographic outcomes. Follow-ups occurred at 3 months, 6 months, 1 year, 2 years, and then every two years after revision.

RESULTS

Mean follow-up was 10.1 years (5-13 years). Distinct improvements were detected in the mean HHS between the preoperative and last follow-up analysis (62.35[±8.49] vs. 84.70[±14.68], respectively, p < 0.001). The key orthopaedic complication rate was 18.2% (27/148). Seven (4.7%) cases experienced a CTHR failure at a mean of 3.4 (±1.2) years after revision MoM-THR, mostly attributed to recurrent dislocation.

CONCLUSION

CTHR might yield an acceptable functional score and a low rate of the key orthopaedic complications.