Tips for Diagnosis and Management of Hip Osteoarthritis (OA)

• Certain types of hip morphology predispose to hip OA e.g. shallow hip socket (hip dysplasia), the hip socket pointing forwards (hip anteversion), an aspherical femoral head (cam morphology).
• Childhood or young adult hip disorders such as congenital hip dysplasia, slipped capital femoral epiphysis and Perthes disease are also linked to a future risk of hip OA.
• Heavy manual labour (farmers/construction workers) or competing in high impact sports (e.g. soccer) at an elite level increases the risk of hip OA.
• Both extremes of activity are considered risk factors- a sedentary/inactive lifestyle and high levels of activity (elite sports/heavy manual labour).
• In recreational athletes, a prior hip injury like a labral tear or femoroacetabular impingement syndrome increases the risk of hip OA.
• Twin studies suggest the influence of genetic factors is about 60% in OA of the hip.
• Overweight/obesity is linked with an increased risk of developing hip OA. However, recent studies have shown that weight loss does not lead to improvements in hip pain or reverse structural disease.
• Risk factors for hip OA progression are comorbidity, subchondral sclerosis, baseline pain severity and physical dysfunction.

Pain and Other Symptoms

• Pain is often non-specific and poorly localised. The most common referral site is the greater trochanter area, followed by the groin, the anterior/lateral thigh and the buttock area.
• Distal referral to the knee occurs in 17% of people, 15% report pain referral to the lower leg (shin).
• While medial thigh pain is not frequently reported, when present, it has a strong association with hip OA.
• Pain walking upstairs, pain walking down slopes, pain turning in bed, pain pivoting or twisting on the leg is suggestive or hip OA.
• Difficultly putting on shoes and socks or cutting toe nails, difficulty getting in and out of the car, difficulty squatting down or rising from a low chair.
• Morning stiffness is common but short-lasting (less than 30 minutes).

Differential Diagnosis

• The absence of certain features makes it less likely a patient is affected by hip OA. Consider another diagnosis where there is no morning stiffness (<30 minutes), no pain on walking, or pain is not eased by sitting down.
• The differential diagnosis of hip pain includes greater trochanteric pain syndrome/gluteal tendinopathy, deep gluteal syndrome (piriformis syndrome), lumbar spine radiculopathy or referred pain, eralgia parasthetica, femoroacetabular impingement syndrome and hip labral tear.
• Serious pathology to exclude are pelvic bone tumours, avascular necrosis, pelvic insufficiency fractures, stress fracture and inflammatory arthropathies (eg, rheumatoid arthritis).

• In general, physical examination findings are more useful than historical features for identifying the presence of hip OA.
• Restricted passive range of hip motion most indicative of OA is internal rotation, followed by adduction.
• Groin pain during passive hip adduction or abduction is suggestive of hip OA.
• Posterior or buttock pain during a squat is a strong indicator of hip OA (increased odds by 6 times).
• Antalgic gait or a limp is typical of hip OA.
• In more advanced stages, you may observe a hip flexion contracture, quadriceps and gluteal atrophy, shortening or internal rotation of the affected limb, and Trendelenburg’s sign.
• Rule out the lumbar spine as source of hip pain using repeated lumbar movements (eg. combined lumbar extension and rotation) and a straight leg raise.

• Radiographic hip OA is very common in the general population (only 21% of patients with radiographic hip OA experience pain). Without first conducting a thorough clinical examination, there is a risk of finding incidental OA and attributing symptoms to x-ray findings.
• When symptoms are mild to moderate, a diagnosis of hip OA can be made clinically without x-ray. With severe or unremitting symptoms, an x-ray is usually indicated to confirm the diagnosis and exclude other pathology.
• A normal radiograph does not exclude OA. Pathologic features and symptoms of OA can occur before osteophytes are present on radiographs.
• Exercise caution in ordering an MRI for hip OA diagnosis. About 50% of patients will have a labral tear. Absence of a relationship between symptoms and structural changes on MRI can create fear of loading and engaging in an exercise program.