Higher risk of knee arthroplasty during ten-year follow-up if baseline radiographic osteoarthritis involves the patellofemoral joint: a CHECK Cohort Study

Table 2 Radiographically confirmed arthroplasties: hazard ratios (HR, 95% CI) for knees (n = 1678 due to missing data for 12 knees at baseline) undergoing arthroplasty over 10-years of follow-up, based on baseline OA compartment involvement (compared to no OA)

Radiographic OA pattern	Number of arthroplasties^a / baseline OA prevalence (%)	Crude HR (95% CI)	Adjusted HR (95% CI) ^b
No OA	11 / 1307 (1%)	[ref]	[ref]
Isolated patellofemoral OA	17 / 182 (9%)	11.9 (5.6, 25.4)	12.7 (5.6, 29.0)
Isolated tibiofemoral OA	2 / 84 (2%)	2.9 (0.6, 13.3)	2.9 (0.6, 13.6)
Combined OA	13 / 105 (12%)	16.6 (7.0, 39.1)	14.2 (5.8, 34.6)
Any patellofemoral OA	30 / 287 (10%)	12.2 (6.3, 23.6)	11.9 (5.8, 24.3) 10.8 (4.9, 24.2) ^c
Any tibiofemoral OA	15 / 189 (8%)	4.4 (2.2, 8.7)	3.7 (1.9, 7.4) 1.3 (0.6, 2.8) ^c

^a 43 arthroplasties included in analysis because 1 knee did not have complete baseline radiography
^b Adjusted for age, sex, body mass index and pain severity (WOMAC pain) at baseline
^c Additional adjustment by OA of the other compartment (i.e. add ‘any tibiofemoral OA’ to the patellofemoral OA model, and vice versa)
Bold indicates p < 0.05

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