[Total knee arthroplasty with Boneloc cement. Clinical and radiological results]

Fifty-five total knee prostheses cemented with Boneloc were assessed clinically and radiographically after a mean follow-up of 64 months.

At follow-up, 11 patients (12 TKR) were dead. One of these patients had both clinical and radiographic signs of loosening of the prosthesis, but was inoperable because of severe cardiopulmonary status. Seven patients (eight knees) refused assessment and two patients (two knees) have been reoperated. The mean duration of follow-up was 64 months (range, 44-97).

The mean clinical knee score (the Hospital for Special Surgery) was 86 (range, 55-97). Overall, the result in 34 knees was excellent; in 14 good; in 5 fair, and in 2 poor. Forty-four prostheses (80 per cent) had no radiolucent lines (the Knee Society scoring system). The rest had radiolucent lines around the tibia component. Nine knees had non-progressive radiolucent lines, one moderate, and one a progressive radiolucency. Radiologically, the last knee was clearly loose, but the clinical result was still good. No correlation was found between the clinical and the radiological results (r = -0.02). There was a significant correlation between the follow-up time and the presence of radiolucency in TKR (r = 0.32, p = 0.02).

The failure rate was 5.12% (four out of 78) within one to four years of the operation. The poor mechanical characteristics of the Boneloc cement indicate that all knees inserted with Boneloc cement should be followed up in order to detect failures early.