Relationship Between Hip and Groin Pain and Hip Range of Motion in Amateur Soccer and Australian Rules Football Players.

Background: The relationship between hip/groin pain and hip range of motion (ROM) is unclear. Purpose: To explore the relationship between hip/groin pain and hip joint ROM and examine the influence of sex and cam morphology on this relationship. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were 184 amateur soccer and Australian Rules football players (276 hips; 20% women; median age, 26 years; interquartile range, 24-30 years) with hip/groin pain >6 months and a positive flexion-adduction-internal-rotation (FADIR) test, and 50 matched asymptomatic control players (98 hips; 28% women, median age, 26 years; interquartile range, 23-31 years). Hip ROM measures were flexion, internal and external rotation at 90° of hip flexion, total rotation (internal and external), and bent-knee fall out (BKFO). Cam morphology was determined from anteroposterior pelvis or 45° Dunn radiographs, defined by an alpha angle ≥60°. Linear regression models with generalized estimating equations were used to examine the relationship between group (symptomatic and asymptomatic) and each ROM measure. Interaction terms (group × cam morphology or group × sex) were included to examine if relationships between group and hip ROM were influenced by cam morphology or sex. Where appropriate, models were adjusted for sex, age, and cam morphology. Results: An interaction between the relationship between group × cam and internal rotation ROM was found. Symptomatic players with cam morphology had lower internal rotation ROM than controls with cam morphology (adjusted mean difference [AMD] = -4.5°; 95% CI, -7.4° to -1.6°). Hip/groin pain was not associated with internal rotation ROM if cam morphology was absent. A significant interaction was also found for group × sex and BKFO and total rotation ROM. Symptomatic women had lower total rotation ROM than control women (AMD = -8.2°; 95% CI, -14.1° to -2.2°), but no difference was seen in men. BKFO range was lower in men with hip/groin pain compared with control men (AMD = 1.6 cm; 95% CI, 0.3-3.0 cm), but no difference was seen in women. Flexion and external rotation ROM did not differ between symptomatic and control hips. Conclusion: Cam morphology was an effect modifier of the relationship between hip/groin pain and internal rotation ROM. Sex-related differences were also observed in the relationship between hip/groin pain and hip ROM.