Mid-term results and factors affecting outcome of a metal-backed unicompartmental knee design: a case series

Table 3 Comparison of patient characteristics between the failure and non-failure groups

	Failure	Non-failure		Hazard Ratio
Variables	(N = 9)	(N = 71)	P value ^a	Ratio	95% CI
Mean age (years)	61 [8]	74 [9]	< 0.01	0.94	0.86-1.03
Male gender (percent)	44	42	1.00	0.30	0.05-1.87
Mean body mass index (kg/m²)	28 [7]	27 [4]	0.71	-	-
Obesity (body mass index ≥ 30 kg/m²) (percent)	44	20	0.11	2.13	0.34-13.3
Diagnosis (percent)				-	-
Osteoarthritis	100	85	0.35	-	-
Osteonecrosis	0	15		0.00	0.00
Mean pre-op objective score (points)	53 [10]	49 [9]	0.21	1.01	0.92-1.11
Mean pre-op functional score (points)	51 [5]	47 [10]	0.30	1.07	0.96-1.19
Pre-op patellar osteophytes (percent of patients)	33	46	0.38	0.27	0.07-2.01

CI = confidence interval
^a p values were calculated based on Wilcoxon rank sum tests for continuous variables, and chi-squared or Fisher exact tests for categorical variables.

ISSN: 1749-799X