Diabetes does not influence the early outcome of total knee replacement: a prospective study assessing the Oxford knee score, short form 12, and patient satisfaction.

BACKGROUND

There is conflicting evidence as to whether diabetes mellitus influences the functional outcome and patient satisfaction after a total knee replacement (TKR). The aim of this study was to assess the effect of diabetes upon the Oxford knee score (OKS), short form (SF)-12, and patient satisfaction after TKR.

METHODS

Prospective pre- and post-operative (one year) OKS and SF-12 scores for 2389 patients undergoing primary TKR were compiled, of which 275 (12%) patients suffered with diabetes. Patient satisfaction was assessed at one year.

RESULTS

Patients with diabetes were more likely to have a greater level of comorbidity (p<0.001), and a worse pre-operative OKS and SF-12 score (p<0.02), compared to those patients without diabetes. Diabetes was not a significant (p>0.41) independent predictor of post-operative OKS or the SF-12 physical score on multivariable analysis. Although, factors more prevalent within the diabetic cohort (heart disease, vascular disease, liver disease, anaemia, depression, back pain, worse pre-operative OKS and SF-12 score) were found to be independent predictors of post-operative OKS and SF-12 physical score. Interestingly, diabetes was associated with a significantly greater improvement in mental wellbeing (SF-12 mental component), which was confirmed on multivariable analysis. Patient satisfaction was not influenced by a concomitant diagnosis of diabetes (p=0.57).

CONCLUSION

The outcome of TKR as assessed by the OKS, SF-12, and overall patient satisfaction rates are not influenced by diabetes per se, although factors more prevalent within this population result in a worse post-operative outcome.

LEVEL OF EVIDENCE

prospective cohort study, level III.