Overview of hip-joint conditions

People use the word ‘hip’ to refer to a number of anatomical structures. When people complain of pain felt in the hip region, care must be taken to define whether their pain is truly arising from the hip joint or from structures lateral to the hip.

People with true hip-joint pathology usually present with groin or anterior thigh pain, which may extend down to the knee. Occasionally, people may only present with pain referred to the knee from the hip. Passive movements (especially rotation) of the hip are often painful or limited. True hip-joint pathology rarely refers pain to the lateral thigh.

Many rheumatological conditions in adults can involve the hip joint and are covered in specific topics including:

• osteoarthritis (OA)
• femoroacetabular impingement and acetabular-labral tear (often associated with OA)
• rheumatoid arthritis
• axial spondyloarthritis
• systemic lupus erythematosus
• polymyalgia rheumatica.

Hip pain resulting in limp is common in children and adolescents. Important conditions to consider in the differential diagnosis of hip pain and limp in children and adolescents include:

• Perthes disease—idiopathic avascular osteonecrosis of the head of the femur; requires urgent surgical referral
• slipped upper femoral epiphysis (SUFE)—slippage of the proximal femoral epiphysis; requires urgent surgical referral
• transient synovitis (irritable hip)—common, idiopathic inflammatory synovitis; often postviral; self-limiting
• septic arthritis and osteomyelitis requires urgent referral for investigation and antibiotics
• acute chondrolysis—rare, idiopathic or secondary to other conditions
• developmental dysplasia of the hip—important to diagnose in infancy to prevent longstanding problems.