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. 2020 Jul 1;102-B(7):941–949. doi: 10.1302/0301-620X.102B7.BJJ-2019-0102.R2

Table III.

Relative threshold values for knee arthroplasty at which patients have a 90%, 80%, 70%, or 50% probability of achieving the meaningful improvement criteria of seven points on the Oxford Knee Score, for both observed data and predictions from quantile regression.

Baseline covariate Total patients Predicted preoperative score corresponding to preselected percentage probability of improvement Observed score
90% 80% 70% 50% 90% 80% 70% 50%
Total, n 222,933 N/A 25 31 36 1 25 30 36
Age category, n
< 60 yrs 29,349 N/A 18 29 35 1 21 30 35
60 to 80 yrs 164,132 N/A 26 31 36 1 26 31 36
> 80 yrs 29,452 13 24 30 35 15 26 30 36
Sex, n*
Male 96,006 N/A 26 31 36 0 26 32 36
Female 126,885 N/A 25 30 35 1 25 30 36
Year of NHS PROMs, n
2009 to 2011 102,448 N/A 24 30 35 1 23 30 36
2012 to 2015 120,485 N/A 27 31 36 1 26 32 36
*

Data missing for 42 patients.

N/A, not applicable; PROMs, patient-reported outcome measures.