Introduction: Playing football may increase a person’s risk of developing hip OA in later life. This may be related to cam morphology, which is present in two thirds of football players. However, the relationship between cam morphology, symptoms and early hip OA is unknown in football players. This study had two aims: 1) examine the relationship between cam morphology and early hip OA features (cartilage defects and labral tears) in football players with and without hip/groin pain; 2) investigate if the association between cam morphology and early hip OA features is stronger in football players with hip/groin pain.
Methods: 182 semi-elite football (soccer/ Australian football) players (288 hips; 50% soccer; age:26yrs; height:1.79m; weight:78kg; 20% women) with hip/groin pain (>6 months of pain and +ve flexion-adduction-internal-rotation test) and 55 semi-elite control football players (110 control hips; 55% soccer; age:26yrs; height:1.79m; weight:79kg; 25% women) without hip/groin pain underwent AP and Dunn 45° radiographs, and 3-tesla hip MRI. Cam morphology was defined using continuous (alpha angle) and threshold (cam morphology >60° to £78°; large cam morphology >78°) values, and cartilage defects and labral tears were scored semi-quantitatively. Presence and location of cartilage defects and labral tears were determined. Logistic regression with generalised estimating equations were used to determine whether cam morphology was associated with early hip OA features. An interaction term was incorporated into all regression models to test if the relationship between cam morphology and early hip OA features was stronger in football players with symptoms.
Results: Greater alpha angle was associated with cartilage defects (OR 1.03, 95%CI 1.01,1.04) and labral tears (OR 1.02, 95%CI 1.01,1.04). Hips with cam (OR 2.12, 95%CI 1.2,3.7) and large cam (OR 2.58, 95%CI 1.5,4.6) morphology had a higher prevalence of cartilage defect than hips without. Only hips with large cam morphology (OR 2.53, 95%CI1.3,4.7) had a higher prevalence of labral tears than hips without. Greater alpha angle was associated with superolateral cartilage defects (OR 1.03, 95%CI 1.02,1.05) and superior labral tears (OR 1.03, 95%CI 1.02,1.05). The association of cam morphology with early hip OA features was no greater in football players with symptoms than in those without (P=0.127 to 0.985)
Discussion: Cam morphology was associated with early hip OA features in adult football players with and without pain. This relationship was no greater in football players with symptoms than without, suggesting a complex relationship between cam morphology, early hip OA features and hip/groin pain
Conflict of interest statement: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.
