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Indications for knee arthroplasty have remained consistent over time.

INTRODUCTION
Between 2004 and 2009, the incidence of primary total knee arthroplasty (TKA) in Denmark has almost doubled. It has been speculated that this increase may be a result of patients being operated on weaker indications. The purpose of this study was to compare preoperative degrees of osteoarthritis and health-related quality of life (QoL) in patients receiving primary TKA in 2004 and 2009.


MATERIAL AND METHODS
We identified 154 and 369 primary TKAs inserted at our institution in 2004 and 2009, respectively. Patients had been invited to complete the Short Form (SF)-36 questionnaire preoperatively. Two groups of patients that were representative with regard to age and gender were randomly sampled and compared (n = 44 in 2004 versus n = 106 in 2009). The Kellgren-Lawrence (K-L) grade of osteoarthritis was assessed on preoperative radiographs in all patients.


RESULTS
We found no statistically significant differences in gender distribution or mean age at surgery. We reached K-L grades of 3-4 in 52.4% and 49.6% in 2004 and 2009, respectively (p = 0.57). The preoperative mean SF-36 physical component scores were 32.6 and 33.7, respectively (p = 0.44). The preoperative mean SF-36 mental component scores were 43.0 in 2004 and 49.3 (i.e. 6.3 points higher) in 2009 (p = 0.003).


CONCLUSION
Preoperative degrees of osteoarthritis and physical health-related QoL did not change from 2004 to 2009. Thus, it seems that these components of operative indications have not weakened. The increased preoperative SF-36 mental component score of these patients may have had a positive effect on postoperative outcomes.


FUNDING
not relevant.


TRIAL REGISTRATION
not relevant.


TRIAL REGISTRATION
not relevant.