Hip pathology radiates pain to a variety of locations and should be considered when a patient presents with hip girdle and lower limb pain. Hip degenerative joint disease (DJD) is common and causes symptoms in an estimated 10% of the population. Women, older patients, those with an increased body mass index, and those with pre-existing biomechanical abnormalities such as hip dysplasia are at greater risk.  

Femoroacetabular impingement (FAI) syndrome consists of bony abnormalities of the femoral head (cam lesions) or acetabulum (pincer lesions) that cause impingement and pain. The cartilaginous labrum of the hip extends the coverage of the acetabulum over the femoral head and seals the hip joint, and when torn can also cause hip and radiating pain. Pain from intra-articular hip pathology usually causes aching pain that begins insidiously, initially with motion and use, but eventually extends to periods of rest and at night.  Stiffness is more specific to hip DJD and occurs after long periods of immobility and generally resolves after 30 minutes of motion.  Mechanical symptoms such as catching, locking, and giving way are more specific to FAI and labral pathology. Clicking is particularly sensitive and specific for hip labral disease in athletes. Pain from the hip joint usually presents in the groin, but over half of patients with labral tears have anterior or lateral thigh pain.  

Anterior thigh and knee pain is common in hip impingement test. With the patient supine and the hip and knee in 90 of flexion, the hip is internally rotated with adduction force applied. A positive test is reproduction of anterolateral hip or groin pain. Importantly, this test can also be used to diagnose FAI. 

Plain films of the hip are usually sufficient to diagnose hip DJD and FAI, but MRI arthrography is the definitive imaging modality toassess for labral pathology. Severity of symptoms and imaging findings often may not correlate in an individual patient. Pathologies ofthe hip usually are treated initially with NSAIDs, acetaminophen, and physical therapy. Intra-articular injections can indicate that the source of the symptoms is within the hip capsule but do not distinguish among different intra-articular pathologies. Intra-articular injections of corticosteroids are also useful for short-term symptom relief, but when conservative measures fail, surgery is often needed if the symptoms significantly impair function

Greater trochanteric pain syndrome (GTPS) 

This has a well-deserved place on the list of musculoskeletal conditions electrodiagnostic medicine(EDX) consultants should be aware of and has earned the name “The Great Mimicker” for being frequently mistaken for other conditions,including radiculopathies.  The name GTPS itself is purposely vague, reflecting the multiple pathologies and pain generators that could bethe source of symptoms in any given patient. GTPS is common, withan incidence 1–2/1000 per year and may affect up to 10%–25% of the population in the industrialized world.  Women are affected more than men by a ratio 3–4:1.  Determining the precise pain-generating structure of GTPS is difficult. The possibilities include gluteus medius and minimus tendinopathy or tears, inflammation of the greater trochanteric or other bursae, the iliotibial band (ITB), or other structures. The exact cause in any given patient is often unknown and could be multiple concurrent pathologies.  Gluteus medius and minimus tendon pathology is likely the most common pain generator, with bursitis rarely present without tendinopathy. The correlation between imaging findings and symptoms is poor, as imaging of these tendons is often abnormal even inasymptomatic patients.  The pathological sequence of events leading to GTPS is thought to begin with increased pressure on the gluteus medius and minimus tendons between the ITB and greater trochanter itself. This leads to tendinopathic changes of the tendons, usually beginning in the anterior fibers of the gluteus medius, then progressing posteriorly into the remainder of the gluteus medius, and the gluteus minimus in severe cases. This will sometimes lead to bursitis of the overlying greater trochanteric bursa.  The symptoms of GTPS overlap substantially with other peripheral neurological and musculoskeletal conditions, particularly facet and sacroiliac joint (SIJ)-mediated pain, lumbar disc degeneration with radiculopathy, and ligamentous strains. In one series, 63% of patients with GTPS were previously evaluated by a spine surgeon for radiculopathy.  Some patients will have pain radiating to the buttock, and as many as 50% will have radiation past the knee, and thus can be confused with radiculopathy.  Common precipitating factors include lying on the affected side, running, prolonged standing or climbing stairs, transitioning to a standing position, or sitting with legs crossed. Fortunately, the physical examination is more helpful in distinguishing GTPS from other mimicking conditions. Pain to palpation over the greater trochanter with radiation to the lateral thigh is a highly sensitive and specific finding, and nearly pathognomonic for GTPS.  Other physical examination findings include pain with lying on the affected side, pain with resisted hip abduction, and the lack of provocation with hip extension, which is common in hip DJD. High-quality evidence is lacking for conservative treatments for GTPS, but corticosteroid injections, topical and oral NSAIDS are supported by some low-quality studies,1and physical therapy is commonly used as well.