One-year Oxford knee scores should be used in preference to 6-month scores when assessing the outcome of total knee arthroplasty
10.1186/s43019-020-00060-5
- Author:
N. D. CLEMENT
1
;
N. NG
;
D. MACDONALD
;
C. E. H. SCOTT
;
C. R. HOWIE
Author Information
1. Department of Orthopaedics, The Royal Infirmary of Edinburgh, 51 Little France Cres, Edinburgh EH16 4SA, UK
- Publication Type:R E S E A R C H A R T I C L E
- From:The Journal of Korean Knee Society
2020;32(4):e43-
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:The primary aim of this study was to assess whether there was a clinically significant difference in the mean Oxford knee score (OKS) between 6 and 12 months after total knee arthroplasty (TKA). The secondary aim was to identify variables associated with a clinically significant change in the OKS between 6 and 12 months.
Methods:A retrospective cohort study was undertaken using an established arthroplasty database of 1574 primary TKA procedures. Patient demographics, body mass index (BMI), comorbidities, OKS and EuroQoL 5-domain (EQ-5D) score were collected preoperatively and at 6 and 12 months postoperatively. A clinically significant change in the OKS was defined as 5 points or more.
Results:There was a 1.1-point increase in the OKS between 6 and 12 months postoperatively, which was statistically significant (95% confidence (CI) 0.8–1.3, p < 0.0001). There were 381 (24.2%) patients who had a clinically significant improvement in their OKS from 6 to 12 months. After adjusting for confounding, patients with a lower BMI (p = 0.028), without diabetes mellitus (p < 0.001), a better preoperative OKS (p < 0.001) or a worse 6-month OKS (p < 0.001) were more likely to have a clinically significant improvement. A 6-month OKS < 36 points was a reliable predictor of a clinically significant improvement in the 6-month to 12-month OKS (area under the curve 0.73, 95% CI 0.70–0.75, p < 0.001).
Conclusion:Overall, there was no clinically significant change in the OKS from 6 to 12 months; however, a clinically significant improvement was observed in approximately a quarter of patients and was more likely in those scoring less than 36 points at 6 months. Level of evidence: retrospective diagnostic study, level III.
