Magnetic Resonance Imaging Findings Following Ceramic-on-Ceramic Total Hip Arthroplasty Using Modular Neck Femoral Components.

BACKGROUND

Adverse reactions to metal debris after total hip arthroplasty are an increasing concern. Metal debris is released from the metal-on-metal articulation itself as well as from the head-neck taper. There is also a risk of corrosion at the neck-stem junction. Some stems were recalled because of high revision rates as a result of metal debris from the modular junction. We conducted a retrospective analysis of the 3-year to 8-year clinical and radiographic outcomes of a consecutive cohort of patients who underwent cementless total hip arthroplasty using a modular hip prosthesis with ceramic-on-ceramic bearings.

METHODS

We retrospectively evaluated 104 patients who had undergone 119 primary ceramic-on-ceramic total hip arthroplasties using modular neck femoral components between December 2006 and November 2012. All hips were implanted with a titanium alloy stem and titanium alloy neck. Clinical outcomes were evaluated using the Japanese Orthopaedic Association hip score. Prosthesis survival was calculated according to the Kaplan-Meier method considering any reason for revision as failure. Postoperative magnetic resonance imaging was performed and graded using a previously described pseudotumor grading system. Mean follow-up was 5.9 years (range: 3 to 8 years).

RESULTS

The mean age of the patients at the time of the index arthroplasty was 59.0 years. Mean hip score improved from 45.9 (range: 9 to 90) preoperatively to 91.5 (range: 65 to 100) at the final follow-up. The overall implant survival rate was 97.3% at 8 years when revision for any reason was used as the endpoint. Abnormalities on magnetic resonance imaging were seen in 16 of 91 hips (17.6%). All abnormalities were cystic thin-walled lesions located in the peritrochanteric area. There was no revision operation due to adverse reactions to metal debris.

CONCLUSIONS

A modular neck femoral prosthesis with ceramic-on-ceramic bearings offers satisfactory 3-year to 8-year results. However, abnormalities on magnetic resonance imaging were seen in one-fifth of the patients, although the clinical significance is unknown.