Long-term survivorship of the Corail™ standard stem.

INTRODUCTION

The Corail™ stem, which was first introduced in 1986, has since been modified twice: first to make the neck thinner and then to change the location of the laser markings. The survival and complications of the first-generation straight, titanium, hydroxyapatite-coated stem are known; however, there is little specific information about the latest-generation stem. This led us to conduct a retrospective study to determine the: (1) long-term survival; (2) clinical and radiographic outcomes; (3) complications; and (4) risk factors for revision of the newest Corail™ stem.

HYPOTHESIS

The newest Corail™ AMT (Articul/EZE™ Mini Taper) standard stem has comparable survival to prior models.

PATIENTS AND METHODS

This single-center, retrospective study included 133 patients (140 hips), who underwent primary total hip arthroplasty (THA), between January and December 2004, in which a Corail™ Standard stem was implanted using a posterolateral approach. Patients who underwent revision THA, THA due to femoral neck fracture or who received lateralized (offset) stems were excluded. The mean age at the time of THA was 69±13 years [35-92] in 85 men (61%) and 55 women (39%) who had a mean BMI of 27kg/m±11 [16-39]. At the latest follow-up, 32 patients (32 hips) had died and 8 patients (8 hips) had less than 3 years' follow-up, thus were not included in the clinical evaluation. The Merle d'Aubigné (PMA) score was collected. The stem's survivorship was calculated using the Kaplan-Meier method with revision for aseptic loosening and revision or implant removal for any reason as the end-points. The Cox model was used to analyze risk factors for revision. The mean follow-up was 10±3 years [3-12].

RESULTS

The PMA score was 12±2.6 [5-17] preoperatively and 16±2.7 [7-18] at the last follow-up (P<0.00001). Eighteen complications (12.8%) were recorded at the last follow-up. There were 15 early complications: 6 dislocations, 5 calcar fractures (4 treated by wire cerclage and 1 by stem change plus wire cerclage), 2 greater trochanter fractures (treated non-surgically) and 2 cases of sciatic nerve palsy. There were 3 late complications: 2 cases of iliopsoas irritation and 1 ceramic insert fracture. Stem survival for surgical revision due to aseptic loosening was 98% (95% CI: [0.96-1]). At 12 years, 95% of stems had not been revised or removed (95% CI: [0.92-0.99]). Being less than 58 years of age at the time of surgery was the only risk factor significantly associated with stem revision for any reason (P=0.04).

CONCLUSION

Survival of the Corail™ Standard stem is similar to that of previous generation stems. The changes made in this stem solved the neck failure problem and did not induce new complications.

LEVEL OF EVIDENCE

Level IV (retrospective study).