Table 2.

Pre-operative and intra-operative features

	PR group N = 60	N-PR group N = 60	P value
Pre-operative Kellgren-Lawrence classification			0.803
III	10	9
IV	50	51
Operation side			0.465
Left	32	28
Right	28	32
Operative time (minutes)	41.70 ± 2.55	38.22 ± 2.70	< 0.001
Blood loss (ml)	36.18 ± 3.46	36.20 ± 3.39	0.957
Post-operative patellar thickness (mm)	21.08 ± 1.39	22.03 ± 1.68	< 0.001

PR, patellar resurfacing; NP, non-patellar resurfacing