INTRODUCTION:

Aseptic loosening continues to be a short and long-term complication for patients with cemented knee replacements. Changes in cemented total knee replacement (TKR) fixation have been limited to assessment of radiographic changes at the implant-bone interface and quantification of component migration. The goal of this study was to determine the interlock morphology between cement and trabecular bone using en bloc postmortem retrieved TKR. Note that these retrievals were not obtained from revision surgery for a loose implant, but rather after death. Thus the implants can be considered successful for the lifetime of the patient. We hypothesized that constructs with greater time in service have less interlock between cement and bone and constructs with more estimated initial interlock sustain more interlock with in-vivo service.

Aim: To prospectively determine whether social deprivation has an effect on the level of disability at presentation and the outcome from total knee replacement (TKR).

Method: A prospective outcome study was carried out between 1992 and 1996, recruiting over 2500 total knee replacements. All patients were assessed preoperatively and at 3 and 12 months postop using the Knee Society (KS) scores for clinical evaluation and the Nottingham Health Profile (NHP) to measure general health status. The Townsend Score was used as the index of social deprivation and was calculated for each patient on the basis of their address.

Results: There was no significant difference between either the Knee Society or NHP scores at baseline and the Townsend Score. This indicated that social deprivation has no effect on the level of the knee arthritis immediately prior to joint replacement, both in terms of patient disability and health status.

There was also no significant difference between either the Knee Society or NHP scores postoperatively and the Townsend Score. This indicated that social deprivation has no effect on the outcome from knee replacement.

Conclusion: This study shows that social deprivation has no significant effect on the level of disability at presentation and the outcome from total knee replacement. This is contrary to previously published reports which have shown worse outcomes in more deprived patients.

Between 1992 and 1994 we performed a prospective study of the effect of total knee replacement (TKR) on the health status of 119 patients over the age of 80 years who had had a primary unilateral TKR.

The Nottingham Health Profile was used to assess this before and at three and 12 months after operation. We found a significant improvement in the scores for pain, emotional reaction, sleep and physical mobility at three months. After 12 months, the scores for pain and sleep were well maintained. The other factors had deteriorated slightly but remained better than before operation.

Our findings show that TKR leads to a significant improvement in the general health status of the very elderly.