Hip pain is a common presenting symptom for primary care visits. Among adults older than 60 years, nearly 15% reported some hip pain when followed over a period of 6 weeks.^1,2 The hip is a complex area of anatomy where underlying pain generators can range from the femoral-acetabular joint and capsule to overlying tendons, muscles, ligaments, nerves, and vascular structures. In addition, overlapping anatomic structures may complicate a differential diagnosis, including perineal, abdominal, and lumbosacral pathology. A systematic approach is essential to effective pain management and treatments. The purpose of this chapter is to review common causes of hip pain and emphasize key aspects of history and physical examination to aid in correct diagnosis and treatment.

A comprehensive history is vital to determining the cause of hip pain. Acquire information such as age, onset of pain, mechanism of injury, description of severity and location, associated symptoms such as numbness and tingling, and aggravating and relieving factors. Carefully review past medical and surgical histories, especially congenital or childhood hip deformities, underlying rheumatologic conditions, history of cancer, or previous trauma involving the lower extremity.

Inquire about previous treatments, and document the response to each treatment. This will help guide your next step in management. The next few sections further describe important aspects of the history and how they correlate to underlying hip pain generators, as well as corresponding physical examination findings.

Acute onset of pain is often associated with an inciting traumatic event or athletic injury. In contrast, chronic hip pain is usually insidious and related to degenerative conditions.³ It is useful to consider the more common causes of hip pain with increasing age.

In general, the mechanism of injury has less importance regarding etiology of hip pain especially because the majority of hip pain is attributed to chronic conditions. However, there are a few notable injuries with characteristic mechanisms.

Traumatic and high-energy injury to the hip region can cause fracture or dislocation. Direct impact or axial loads to the pelvis or femur from a fall or motor vehicle accident can lead to fractures.^2,7 If a fracture is present, pain will be severe and physical examination will typically reveal deformities. On inspection, the affected limb may appear shortened compared with the uninjured extremity.

A common nontraumatic cause of hip dislocation is following hip replacement surgery. Patients are instructed to avoid specific postoperative range of motion, especially excessive hip flexion and adduction for several months if a posterior surgical approach was used. Nearly 90% of all hip dislocations occur in the posterior direction. A posterior dislocation will present with the affected limb in flexion, adduction, and internal rotation. In contrast, an anterior dislocation will present with limb in flexion, abduction, and external rotation.

Muscle strains are another common cause of acute hip pain with notable mechanism of injury, especially when related to physical activity. Acute onset of groin pain after injury is most often caused by an adductor muscle strain. This injury occurs in sports owing to sudden changes of lateral direction and is characterized by the patient as a “pull” in the groin region. The adductor group is composed of 6 muscles, but the most commonly injured muscle is the adductor longus. Acute anterior hip pain located lateral to the groin can reflect strain of the hip flexor, rectus femoris, or iliopsoas muscles. These muscles are frequently injured during eccentric quadriceps contraction such as bringing the hip into extension during kicking activities. A patient with a recent hip flexor strain will often have pain and difficulty with an active straight leg raise. Hamstring strains are a common cause of acute posterior gluteal or thigh pain. The mechanism of hamstring injury can be from explosive sprinting activity, which causes excessive eccentric stretch of the muscle group. The patient may note a “pop” or “pull” in the posterior thigh and will have difficulty with walking.

Repetitive activities may make certain individuals prone to specific hip conditions. One such condition is athletic pubalgia or sports hernia, which is caused by repetitive hyperabduction of the abdominal muscles on the pubis. The repetitive rotation of the upper leg and torso common in athletes playing ice hockey, soccer, and rugby causes a higher risk of athletic pubalgia. Dancers also represent a distinct population. Owing to extreme range of motion of the hip, dancers are vulnerable to labral tears. Finally, people who play sports that require repeated single leg stance are at high risk of developing posterior hip pain because of sacroiliac joint dysfunction.⁵

Asking the patient to identify the pain location will help narrow the differential diagnosis. A simple test to specifically isolate location is to have the patient point with one finger where pain is the most intense. Location of hip pain can be generally categorized as anterior, lateral, or posterior. However, there can be considerable overlap in location for several common causes of hip pain.

Traditionally, pain localizing to the anterior hip or groin suggests primary involvement of the hip joint or intra-articular pathology. Patients may indicate hip pain by cupping the anterolateral hip with their thumb and forefinger in the shape of a “C.” This is referred to as the “C sign” (Figure 20-1). Common causes of intra-articular hip pain include osteoarthritis, labral tears, femoroacetabular impingement (FAI), avascular necrosis, septic arthritis, fracture, chondral lesions, loose bodies, and ligamentum teres tears.⁸ Associated mechanical symptoms such as snapping, popping, locking, and reduced range of motion are more often associated with intra-articular pathology.^8,9 Other causes of anterior groin pain may be from extra-articular hip pathology. These include sports hernia (athletic pubalgia), osteitis pubis, adductor strain, or abdominal/pelvic viscera conditions such as hernia, genitourinary pathology, and abdominal strains. A notable cause of extra-articular anterior pain with mechanical symptoms is internal snapping hip or snapping of the iliopsoas tendon.⁶