GENERAL HEALTH STATUS 18 MONTHS AFTER TOTAL KNEE REPLACEMENT COMPARED WITH THAT OF A REFERENCE POPULATION

Abstract

Purpose:

1. To describe the health status of patients after total knee replacement (TKR) and compare it with the state of health of a comparative Spanish population

2. To compare generic and specific measurements of health related quality of life (HRQofL) in patients 18 months after TKR.

Materials and methods: This is an observational analytical study The following variables were assessed: sociodemographic, clinical and HRQofL. Health status was determined by means of generic and specific questionnaires (SF-36 and WOMAC). The age (65–74 years of age) and sex (VPR) values of the comparative population were used. Statistical analysis: mean values and standard deviation were calculated for continuous variables; percentages were determined for categorical variables and Spearman’s correlation analysis was used to determine the correlation of quality of life variables.

Results: There were 82 patients of 72.5 years of age (SD 7.5), 78% were women. There were significant differences between the preoperative and the postoperative WOMAC in pain, stiffness and function (p< 0.001, p=0.035, p< 0.001, respectively). Seventy-nine percent of the patients reported improvement after surgery, and an improvement in general health was also seen (SF-36). However, these values did not reach those of the comparison population in terms of physical function and pain (51.5 vs 61.3 and 50.7 vs 59.0, respectively for women and 60.5 vs 68.9 and 65.0 vs 76.7 for men). The rest of the figures were comparable to those of the comparison population. The correlation between WOMAC function and SF-36 physical function was 87% and that between WOMAC pain and SF-36 body pain, 77%; both were statistically significant (p< 0.001).

Conclusions: Patients reported improvement after TKR both in terms of function and pain and also in their general health status although they did not achieve the values of the comparative population as regards physical function and pain. The correlation between both questionnaires was extremely high, therefore, it is possible to leave aside the specific questionnaire and use the SF-36 since it provides multidimensional information on patients’ HRQofL.