An evaluation of hip pain begins with considering the multiple structure/function relationships that comprise the joint itself and the surrounding soft tissue structures. The hip joint comprises the proximal femur and acetabulum, articular surfaces, and synovium. Peri-articular soft tissues comprise Bursae (e.g., greater trochanteric, iliopsoas, ischial), tendons (e.g., hip abductor, adductor, internal-external rotators, extensors, flexors, and hamstrings), and acetabular labrum which is the soft-tissue rim surrounding the acetabulum.
The clinician should also consider other structural abnormalies, such as inguinal and femoral herniae, and the possibility that the pain complained of in the hip is actually referred from another location, e.g. lower back, knee and even visceral organs such as the gastrointestinal tract, prostate, ovary and aorta.
The most important initial step in the history is to ask the patient to point to the area of “hip pain”. Most will point to their back or their lateral thigh, not their groin. In general, hip pain is groin pain. Patients with true hip pain usually complain of limitation of hip motion, a painful limp and groin pain on movement, less often at rest and rarely at night. Careful history taking may reveal childhood hip disorders such as Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, developmental dysplasia of the hip, and septic arthritis. Concomitant disorders such as osteoarthritis, rheumatoid arthritis (RA), psoriatic arthritis or ankylosing spondylitis, malignancy, or low back pain may provide insight into the etiology of the hip pain. A history of alcohol or steroid use is pertinent in patients suspected of having osteonecrosis. Response to prior therapies, including physical therapy, anti-inflammatory medications, modification of activity, night pain, or use of assistive devices helps one to assess the severity of the pain. Accompanying fever, chills, weight loss or fatigue, or a history of recent infection are important symptoms that could reflect an infected hip or metastatic lesion.
RELATION OF PAIN TO ACTIVITY
- DURATION AND LOCATION OF PAIN
Pain of short duration is usually post-traumatic or inflammatory.
- Pain that is chronic and progressive may indicate mechanical joint incongruity related to an underlying arthritis. The pain of osteoarthritis is usually alleviated with rest. Constant hip pain, especially if severe and unresponsive to simple pain mediocations, is characteristic of an inflammatory/septic or neoplastic process. Synovitis due to RA or psoriatic arthritis tends to be worse in the morning; however, it may not go away completely during the day. It rarely causes night pain unless there is an associated infection or it has led to severe secondary osteoarthritis
- Groin pain with radiation into the buttock indicates hip joint dysfunction. Pure buttock or back pain without a groin component is usually back in origin. When patients say their hip hurts, they mostly point to the buttock. Lateral hip pain with radiation to the lateral thigh may be related to greater trochanteric bursitis or abductor tendinitis. Discomfort over the anterior superior iliac spine extending down the anterior thigh is associated with meralgia paresthetica (inflammation of the lateral femoral cutaneous nerve). Medial groin pain can be due to adductor tendinitis, sometimes associated with overuse or Yoga positions, or a pubic ramus fracture. Hip pain can also be referred to the knee via the obturator nerve.
- Buttock pain may be related to ischial tuberosity bursitis or spinal disorders such as spinal stenosis, ruptured intervertebral disk, and instability.
DECREASED FUNCTION. Patients complain of progressive decrease in maximum walking distance and exercise tolerance. Ability to perform activities of daily living is decreased. These decreases can be quantified with functional assessment scores such as WOMAC, the Harris Hip Score, and SF-36 (Chapter 9). Persistently severe hip pain that limits function and awakens a patient at night should stimulate consideration for an infection, fracture, metastatic lesion or very severe osteoarthritis.
- Pain from the hip joint and surrounding soft tissues is usually aggravated by weight bearing and relieved by rest.
- Patients will usually describe a specific position of the limb that exacerbates or relieves their symptoms.
- GAIT. Observe the patient entering the examination room, and note the presence of a limp or expressions of pain.
- Abductor lurch (Trendelenberg gait). The patient shifts the center of gravity over the affected limb during the stance phase of gait to unload weakened abductors and avoid pain production.
- Coxalgic gait. The patient quickly unloads the painful leg while bearing weight. Decreased stance phase of gait and stride length on the affected side will be seen.
- Stiff hip gait. The patient will walk by rotating the pelvis and swinging the legs in a circular fashion.
- PATIENT STANDING
- Measure unequal leg lengths by balancing the pelvis with calibrated blocks, if necessary. Note a fixed pelvic obliquity if presen
- Evaluate the spine for scoliosis or kyphosis.
- Trendelenburg’s sign. While bearing weight with one leg on the affected side, the patient will drop the opposite side of the pelvis because the hip abductor, which normally elevates the pelvis, is weakened. This may take 30 to 45 seconds to become apparent.
- PATIENT SUPINE
- Record active and passive range of motion, and compare with values of the opposite side.
- Note flexion, extension, abduction, adduction, and internal-external rotation in both flexion and extension. Internal rotation is usually most affected in most types of arthritis (osteoarthritis and RA) and this motion commonly will stimulate pain along with the limitation in range of motion.
- Snapping hip (coxa sultans) can be elicited with range of motion.
- Thomas test for hip flexion contracture. Flex the contralateral knee and hip; extend the affected hip while keeping the lower back flat on the examination table. Note the amount of affected hip flexion present against the horizontal.
- Patrick’s test for sacroiliac joint symptoms. While the patient is supine, place the affected side in a figure 4 position with knee flexed and ankle on opposite knee. Apply pressure to the knee. A positive result exists if significant pain is present in the contralateral sacroiliac joint.
- Hip apprehension test for acetabular labrum pathology. Flex, adduct, and internally rotate the affected limb while looking for pain.
- Palpate the anterior hip capsule by applying pressure just inferior to the inguinal ligament over the femoral triangle, and evaluate the degree of tenderness. Assessment for adenopathy is important to rule out a systemic disease.
- Palpate the groin in supine and standing positions, searching for femoral or inguinal herniae.
- Measure thigh circumference bilaterally to assess muscle atrophy.
- Measure leg lengths with a tape measure, recording from umbilicus to medial malleolus and from anterior superior iliac spine to the medial malleolus. Note whether a fixed pelvic obliquity is present.
- Perform a complete neurovascular examination.
- Examine the knee and ankle. Patients with RA will often present with polyarticular involvement. Functional status often reflects the integral of the effects of back, hip, knee and ankle disease.
- PATIENT LYING ON UNAFFECTED SIDE
- Palpate the greater trochanteric area for bursal tenderness.
- Assess abductor muscle power.
- Ober’s test for iliotibial band tightness. With the patient in the lateral position, extend the affected hip and attempt adduction. If you are unable to do this, the test result is positive.
- PATIENT LYING PRONE
- Palpate the lumbosacral area to evaluate the low back as a potential source of pain.
- Evaluate hip extensor power.
- Palpate the sciatic notch for tenderness.
- Ely’s test for hamstring tightness. With the patient prone, extend the knees until the buttocks are raised involuntarily. A positive result exists if this happens.
- A complete blood cell count with differential, measurements of erythrocyte sedimentation rate or C-reactive protein are appropriate if you believe that a systemic illness might be the cause of hip pain. Rarely, a hip aspiration should be performed if inflammatory joint disease and/or infection are suspected.
- Serum and urine immunoelectrophoreses should be performed to rule out multiple myeloma in patients with bone pain in the setting of anemia and an elevated ESR.
- Radiographs should include an anteroposterior view of the pelvis, and anteroposterior and lateral views of the affected hip. Lumbosacral films should be obtained if spinal pathology is present. Current films should be compared with prior ones, if available, to look for progression of disease. In osteoarthritis, patients’ symptoms may often not correlate with the degree of radiographic involvement of the affected hip.
- Degenerative changes in the hip joint, with osteophytes, subchondral sclerosis, localized joint space narrowing, and cyst formation, are consistent with osteoarthritis.
- Peri-articular osteoporosis and global joint space narrowing is seen in RA. Osteophytes are not typically present unless the patient has had long-standing joint damage and has developed secondary osteoarthritis. .
- In cases of bone involvement by a neoplastic process, tissue erosion of 50% can occur before being detected on radiographs.
- Ultrasound can define joint space narrowing, synovitis and effusion and can optimally guide joint aspiration and steroid injections. Power Doppler can give a rough estimate of the amount of synovial inflammation.
- Computed tomography (CT) may be used to visualize complex acetabular pathology, and to determine the degree of bone involvement in a neoplastic or fracture process.
- Magnetic resonance imaging (MRI) is the most sensitive tool for diagnosing occult hip fractures and osteonecrosis.
- HIP JOINT
- Acetabulum and proximal femur
- Fractures may occur in the femoral neck or intertrochanteric region. Fractures may also occur to the acetabulum after trauma. Stress fractures of the femoral neck or acetabulum, particularly in runners and patients with osteoporosis, may be seen. Public ramus fracture can lead to medial groin pain and tenderness. These can sometimes occur bilaterally along with sacral fractures in patients with osteoporosis.
- Primary or metastatic tumors may infiltrate the femoral head and acetabulum, and pathologic fractures may occur. The most common tumors to metastasize to bone are breast, lung, prostate, kidney, and thyroid. The most common primary tumor of bone is multiple myeloma.
- Osteonecrosis of the femoral head with or without collapse may produce severe hip pain, especially in alcoholics, patients taking steroid preparations and steroid-treated patients with systemic lupus (Chapter 52).
- Transient regional osteoporosis can affect the hip and cause severe hip pain and dysfunction.
- Articulating surfaces
- Osteoarthritis, RA, ankylosing spondylitis, psoriatic arthritis or septic arthritis may cause hyaline cartilage destruction with resultant hip joint incongruity and pain. The association of fever and hip pain must bring up the specter of an infected hip, a medical emergency.
- Incongruity of the femoral head and subsequent arthritis can be seen in osteonecrosis with segmental collapse, or in the adult manifestations of pediatric hip disorders such as Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, and developmental dysplasia of the hip.
- Synovitis of the hip joint may result from RA, spondyloarthropathies such as ankylosing spondylitis and psoriatic arthritis, viral infections especially in children who can present with transient synovitis of the hip and hemophilia.
- Septic arthritis is most commonly caused by gram-positive organisms such as staphylococcus aureus and streptococci and more rarely by gram negative bacilli. In prosthetic joint infections one must also consider staphylococcus epidermidis. The patients that most likely to develop this type of infection is immunosuppressed with a history of prior joint damage in the hip. The common presentation is severe pain of acute onset along with fever and chills. This is a medical emergency and demands optimal cultures, antibiotics and often hip drainage by needle or surgery (Chapter 46).
- Tuberculosis may lead to a proliferative synovitis and severe joint destruction on both sides of the joint. Hip aspiration, acid-fast stain, rarely polymerase chain reaction, and histologic assessment culture confirm the diagnosis. This problem is discussed in chapter xxx
- Synovial chondromatosis is a benign cartilage tumor of the synovium that usually presents with pain and a decreased range of motion.
- Pigmented villonodular synovitis is a synovial proliferation in the hip joint characterized histologically by hemosiderin-stained synovium and giant cells. This may lead to cyst formation in the femoral neck or joint destruction. The radiographic changes seen are present on both sides of the joint.
- PERIARTICULAR SOFT TISSUES
- Greater trochanteric bursitis is common and produces acute pain over the lateral thigh, which usually radiates distally. Swelling and pain with weight bearing are often present, and a limp may result. Pain is present when the patient is lying on the affected side and often awakens the patient from sleep.
- Iliopsoas bursitis is uncommon. It may communicate with the hip joint in 15% of patients.
- Tendons and fascia
- Hamstring, adductor, abductor, and rotator tendons may become inflamed at their insertions into bone. Piriformis syndrome is diagnosed by pain in the sciatic notch with palpation and resisted external rotation.
- The fascia lata is quite taut as it passes over the greater trochanter and may produce a snapping sensation and pain, particularly on hip flexion and adduction. Other causes of a “snapping hip” (coxa sultans) include a tight iliopsoas tendon and hypertrophic fovea.
- Inguinal herniae, if symptomatic, may produce severe groin pain and limitation of hip motion.
- Femoral herniae with prolapse may produce severe groin pain and limping. However, pain is intermittent until incarceration occurs.
- Referred pain
- Lumbosacral. Osteoarthritis involving the lumbosacral apophyseal joints can produce buttock pain. Radicular pain from nerve root irritation may be manifested in the lateral thigh or groin. Disk herniations involving L1-2 and L2-3 may produce these symptoms. Pott’s disease, tuberculous infection of the intervertebral disks and vertebral bodies, may spread to the hip joint via the psoas muscle insertions along the anterior portion of the lumbar spine. At times an injection of lidocaine and steroids into the hip joint via ultrasound guidance is needed to differentiate whether the “hip pain” arises from the hip itself or is referred from the back.
- Visceral origin
- Renal colic can radiate to the groin. Ovarian or prostate disorders may mimic hip pathology.
- Vascular occlusive disease of the aorta can produce buttock pain; femoral vein phlebitis can present with thigh and groin pain.
(For therapy of specific disease entities, see the appropriate chapters.)
- Joint rest may be accomplished by unloading the affected hip with various forms of external support. A cane should be held in the contralateral hand to assist weakened abductors and to unload the hip. Forearm crutches or axillary crutches can be used in more severe disease or bilateral involvement.
- If an acute inflammatory condition involves a tendon or bursa, ice compresses are useful.
- For chronic pain, moist heat improves local blood supply and relaxes spastic musculature.
- Anti-inflammatory medications are useful for arthritic problems involving the hip joint. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful. These medications may be contraindicated in patients taking anticoagulants or who have peptic ulcer or renal disease.
- Analgesics may be used in conjunction with an anti-inflammatory drug.
- Soft-tissue injections. For bursitis or tendinitis, local injection with a corticosteroid such as 40 mg of methylprednisolone acetate (Depo-Medrol) and 3 to 5 mL of 1% lidocaine is effective. If no improvement occurs after one injection, two more weekly injections may be given or the injection can be performed under ultrasound guidance to assure optimal needle placement.
- Attempts should be made to maintain passive and active hip motion without aggravating the underlying pain.
- Gentle isometric exercises for the quadriceps and hamstrings and antigravity exercises as tolerated for hip flexors, extensors, abductors, adductors, and rotators are recommended. See Chapter 61 for specific exercise prescriptions. Weight reduction is an important aspect of the treatment of hip disorders. Hip mechanics cause every pound of weight to be perceived by the hip as being five pounds. The prognosis in many hip disorders is guarded if aggravating factors such as obesity are not addressed.