Table 2.

Knee osteoarthritis, severe knee injury and surgery, and physical knee function among current and retired professional footballers

	Current professional footballers	Retired professional footballers
Prevalence of knee OA (%; 95%CI)	12.9 (10.6–15.1)	27.5 (22.8–32.1)
Severe knee injuries (mean; min-max)
Total	0.7 (0–10)	1.4 (0–10)
No knee OA	0.6 (0–10)	0.8 90–10)
Knee OA	1.7 (0–10)	3.2 (0–10)
Knee surgeries (mean; min-max)
Total	0.5 (0–7)	1.2 (0–10)
No knee OA	0.3 (0–6)	0.7 (0–10)
Knee OA	1.4 (0–7)	2.8 (0–10)
KOOS-SP (mean ± SD)
Total	88 ± 16	82 ± 19
No knee OA	90 ± 14	88 ± 16
Knee OA	76 ± 20	64 ± 16
Reference value KOOS-SP (mean)
General populationa	87–92	87–92
Young athletic populationb	86–99	86–99
Amateur footballersc	87–96	87–96

No OA group without knee osteoarthritis, OA group with knee osteoarthritis, SD standard deviation, ^a Paradowski et al. 2006, ^b Cameron et al. 2013, ^c Frobell et al. 2008