Patient characteristics, diagnosis and physical impairments in young to middle-aged patients with longstanding hip and groin pain

Longstanding hip and groin pain is common in physically active populations and may result in impaired function in daily life and restrictions in sports and physical activities. Diagnostics is challenging in patients with hip and groin pain where both intra-articular and extra-articular structures are potential sources of pain. Pain that originates from intra-articular structures is referred to as hip-related pain, the most common cause of which is femoroacetabular impingement (FAI) syndrome. Patients referred to tertiary care often have hip-related pain and any potential differences in patient-reported and objectively-measured impairment between patients with hip-related pain and non–hip-related groin pain are unknown. Diagnostic criteria for FAI-syndrome have been proposed, however, further investigations on the diagnostic accuracy of the clinical tests used to identify patients with FAI-syndrome are needed. The overall aim of this thesis was to investigate patient-reported and objectively-measured outcomes in young to middleaged physically active patients referred to tertiary care due to longstanding hip and groin pain. Specifically, I aimed to describe and compare patient characteristics, patient reported outcomes, and physical impairments between patients with hip-related pain and those with non–hip-related groin pain, as well as to investigate the diagnostic accuracy of the clinical assessment used to identity patients with FAI syndrome. Two cross-sectional studies were conducted where patient characteristics (sex, age, BMI), patient reported outcomes (pain distribution, activity level, disease-specific symptoms and function, general physical and mental health), and physical impairments (hip range of motion (ROM), muscle function, and performance in functional tasks) were described and compared between patients with hip-related pain and those with non–hip-related groin pain (Papers I and II). Inter-rater agreement and diagnostic accuracy were evaluated by clinical exams, including hip impingement tests and hip ROM tests, both used for identifying patients with FAI-syndrome (Paper III). The association between hip ROM and cam morphology and the diagnostic accuracy of cut-off values for hip ROM to detect cam morphology were calculated (Paper IV). The hip-related groin pain group had more men, a higher activity level during adolescence, and a higher pre-injury activity level, compared to the non–hip-related groin pain group. No differences between hip-related groin pain and non–hip-related groin pain were observed for age, BMI, pain distribution, disease-specific symptoms and function, or general physical and mental health (Paper I). Patients with hip-related pain showed reduced hip ROM in internal rotation compared to patients with non–hip-related groin pain and controls. No differences in muscle function or performance in functional tasks were observed between patients with hip-related pain and those with non–hip-related groin pain. Both patient groups had worse muscle function and worse performance in functional tasks compared to controls (Paper II). Three impingement tests showed substantial agreement between two raters. All passive hip ROM tests, with the exception of extension, showed moderate inter-rater agreement. The impingement test showed high sensitivity and low specificity, whereas hip ROM tests in internal rotation showed high specificity and low sensitivity (Paper III). A cut-off of 27° in internal rotation showed high sensitivity and specificity for detecting patients with cam morphology (Paper IV). Based on these findings, early optimal treatment options—especially exercise-based treatment—for all patients despite diagnosis are needed to improve general health and improve hip-related symptoms and function. Exercise-based treatment should target several aspects of muscle function and performance in functional tasks both for patients with hip-related pain and those with non-hip-related groin pain. Treatment to improve hip ROM, in particular internal rotation, may be needed for patients with hip-related pain. A combination of results from hip impingement tests and hip ROM tests may improve diagnostic accuracy in identifying patients with FAI syndrome. Measurement of hip ROM in internal rotation may be used to identify cam morphology in patients with longstanding hip and groin pain.