Ceramic bearings for total hip arthroplasty have high survivorship at 10 years

Abstract

Background: Ceramic bearings were introduced to reduce wear and increase long-term survivorship of total hip arthroplasty. In a previous study comparing ceramic with metal-on-polyethylene at 5 to 8 years, we found higher survivorship and no osteolysis for the ceramic bearings.

Questions/purposes: We asked whether ceramic bearings have equal or superior survivorship compared with that for metal-on-polyethylene at longer followup; we also determined survivorship of the implant systems, the presence or absence of radiographic osteolysis, and incidence of device squeaking.

Methods: Five surgeons at five sites have followed 189 patients (216 hips) for a minimum of 10 years and average of 10.3 years (range, 10-12.4 years) comparing alumina ceramic bearings (144 hips) with cobalt chrome-on-polyethylene bearings (72 hips). We determined Kaplan-Meier survivorship of the bearing surface and implant systems and collected radiographic and clinical data.

Results: We observed no difference between the control metal-on-polyethylene and the alumina-bearing couple cohorts with regard to bearing-related failures (98.9% versus 99.1%). Revisions for any reason occurred in 10.5% of the control patients and 3.1% of the patients with alumina bearings. All femoral implants remain well fixed (100%), whereas one acetabular component (1%) is unstable in the control group. Osteolysis occurred in 26% of the control patients and in none of the patients with alumina bearings. Squeaking occurred in two of 144 hips (1.4%) of the patients with ceramic bearings.

Conclusions: Patients receiving the ceramic-on-ceramic bearings had fewer revisions for any reason and less osteolysis than the control metal-on-polyethylene at 10 years. Our data suggest ceramic bearings continue to provide an option for the young and more active patient and provide for a measure to compare other new alternative bearings that are currently available.

Level of evidence: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

The cementless components used in the ABC clinical study are shown. System I is a titanium porous-coated acetabular shell, with an alumina ceramic insert and an alumina ceramic femoral head. System II is a titanium arc-deposited, HA-coated acetabular shell, with an alumina ceramic acetabular insert and an alumina ceramic femoral head. The control system (denoted as System III) includes a titanium porous-coated acetabular shell, with a polyethylene acetabular insert and a cobalt-chrome femoral head.

Fig. 2

The K-M survivorship with the end point bearing surface revision is no different for the three study groups at 10 years followup: System I, 100%; System II, 98.6% (90.8%–99.8%); and System III, 98.9% (92.3%–99.8%) (log rank test p = 0.152).

Fig. 3

The K-M survivorship of the bearings, assuming lost to followup were revised, shows no statistical differences among the three groups (p = 0.951).

Fig. 4

The K-M survivorship with the end point revision for any reason is significantly different for the three study groups at 10 years followup: System I, 97.9% (91.9%–99.5%); System II, 95.2% (87.8%–98.3%); and System III, 91.3% (83.4%–95.6%) (log rank test p = 0.027).

Fig. 5

The K-M survivorship end point revision for any reason, assuming all lost to followup were revised, shows no statistical differences among the three study groups (p = 0.617).

Fig. 6A–B

(A) A 6-week postoperative radiograph of the hip of a 38-year-old woman with a control polyethylene bearing is shown. (B) A 4-year radiograph shows osteolysis in Zones 1, 7, and greater trochanter.

Fig. 7

The patient was 48 years old at the time of implantation. His 12-year postoperative radiograph shows no osteolysis of the ceramic-ceramic bearing.