Table 2. Prevalence of radiographic abnormalities in hocks of starters and failure to start a race; 976 horses.

Radiographic abnormalities	Over all incidence	Category	Starters		Failure to start a race		Odds ratio	95% confidence interval	P value
			Numbers	Prevalence	Numbers	Prevalence
Lucency/fragment at the medial malleolus of a tibia	12 horses	Present	12	100.0	0	0.0	N/A	N/A	1.00
	1.2%	Absent	894	92.7	70	7.3
Lucency/fragment at the intermediate ridge of a tibia	66 horses	Present	62	93.9	4	6.1	0.8	0.3–2.3	1.00
	6.8%	Absent	844	92.7	66	7.3
Lucency/fragment at the lateral trochlear ridge of a talus	9 horses	Present	7	77.8	2	22.2
	0.9%	Absent	899	93.0	68	7.0
Lucency/fragment at the medial trochlear ridge of a talus	85 horses	Present	83	97.7	2	2.4	0.3	0.07–1.2	0.08
	8.7%	Absent	823	92.4	68	7.6
Osteophytes in tarsometatarsal joints	91 horses	Present	81	89.0	10	11.0	1.7	0.8–3.4	0.14
	9.3%	Absent	825	93.2	60	6.8
Osteophyte in distal intertarsal joints	295 horses	Present	270	91.5	25	8.5	1.3	0.8–2.2	0.34
	30.2%	Absent	636	93.4	45	6.6
Wedging or collapse of tarsal bones	11 horses	Present	8	72.7	3	27.3	5.0	1.3–19.4	0.04a
	1.1%	Absent	898	93.1	67	6.9
Slab fracture of tarsal bones	14 horses	Present	12	85.7	2	14.3	2.2	0.5–10.0	0.27
	1.4%	Absent	894	92.9	68	7.1

N/A=Not applicable, All P values are for Fisher’s exact test. a) Prevalence (%) was significantly (P<0.05) difference.