Snapping hip syndrome
Snapping hip syndrome (coxa saltans, iliopsoas tendinitis,  or dancer's hip) is a condition characterized by a snapping sensation when the hip is flexed and extended. This may be accompanied by an audible snapping or popping noise and possibly pain or discomfort. Pain often decreases with rest and diminished activity.  Snapping hip syndrome is classified by location of the snapping, either extra-articular or intra-articular.

# Symptoms
An audible snapping or popping noise as the tendon at the hip flexor crease moves from flexion to extension.  Less than one third of patients experience pain with snapping however after extended exercise pain or discomfort may be present caused by inflammation of the iliopsoas bursae.  Pain often decreases with rest and diminished activity.  Symptoms usually last months or years without treatment.

## Extra-articular
- Lateral extra articular
The more common lateral extra articular type of snapping hip syndrome occurs when the iliotibial band, tensor fascia lata, or gluteus medius tendon slides back and forth across the greater trochanter. This normal action becomes a snapping hip syndrome when one of these connective tissue bands thickens and catches with motion. The underlying bursa may also become inflamed, causing a painful external snapping hip syndrome.
- Medial extra-articular
In this case the iliopsoas tendon catches on the anterior inferior iliac spine (AIIS), the lesser trochanter, or the iliopectineal ridge during hip extension, as the tendon moves from an anterior lateral to a posterior medial position. With overuse, the resultant friction may eventually cause painful symptoms, resulting in muscle trauma, bursitis, or inflammation in the area.

## Intra-articular

# Causes of Injury
Athletes are at special risk for snapping hip syndrome due to repetitive and physically demanding movements.  
In athletes such as ballet dancers, gymnasts, track and field athletes and soccer players the repeated hip flexion movements lead to injury . In heavy weightlifting and excessive running the cause is usually attributed to extreme thickening of the tendons in the hip region. Snapping hip syndrome most often occurs in patients aged 15-40 years old.

## Extra-articular snapping hip syndrome
Extra-articular snapping hip syndrome is commonly associated with; leg length difference (usually the long side is symptomatic), tightness in the iliotibial band (ITB) on the involved side, weakness in hip abductors and external rotators, poor lumbopelvic stability and abnormal foot mechanics (eg, overpronation).  Popping occurs when the thickend posterior aspect of the ITB or the anterior gluteus maximus rubs over the iliopectineal eminence or the femoral head as the hip is extended.

## Intra-articular snapping hip syndrome
Similar causes as extra-articular snapping hip syndrome but often with an underlying mechanical problem in the lower extremity. The pain associated with internal variety tends to be more intense and therefore more debilitating than the external variety. Intra-articular snapping hip syndrome is often indicative of injury such as a torn acteabular labrum, recurrent hip subluxation, ligamentum teres tears, loose bodies, articular cartilage damage, or synovial chondromatosis (cartilage formations in the synovial membrane of the joint).

# Treatment
This condition is usually curable with appropriate treatment, or sometimes it heals spontaneously. If it is painless, there is little cause for concern.
Correcting any contributing biomechanical abnormalities and stretching tightened muscles (eg, iliopsoas muscle, iliotibial band) is the goal of treatment to prevent recurrence.
Referral to an appropriate professional for an accurate diagnosis is necessary if self treatment is not successful or the injury is interfering with normal activities.  Medical treatment of the condition requires determination of the underlying pathology and tailoring therapy to the cause. The examiner may check muscle-tendon length and strength, perform joint mobility testing, and palpate the affected hip over the greater trochanter for lateral symptoms during an activity such as walking.

## Self Treatment
Because this is a soft tissue injury of the iliopsoas muscle it should be treated like any other soft tissue injury. At the onset of pain a HI-RICE (Hydration, Ibuprofen, Rest, Ice, Compression, Elevation) regimen should be performed for at least the first 48 to 72 hours.
Rest while treating the problem; no running, jumping, hiking (especially running or hiking hills).  Avoid sit-ups or leg lifts/flutter kicks.
Stretching of the tight structures (piriformis, hip abductor, and hip flexor muscle) can alleviate the symptoms (see link, pg. 3, for examples of stretches .)  Once a stretch of the involved muscle is obtained, hold the stretch 30 seconds and repeat 3 repetitions (with 30 second to 1 minute rest between repetitions). Perform stretching twice per day for 6-8 weeks.
Slowly progress back into jogging once you are symptom-free.

## Diagnostic Imaging
- Ultrasound during hip motion may visualize tendon subluxation and any accompanying bursitis when evaluating for iliopsoas involvement in medial extra-articular cases.
- MRI can sometimes identify intra-articular causes of snapping hip syndrome.

## Surgical Treatment
If the patient does not respond well to medicine or physical therapy, or abnormal structures are found, surgery may be recommended.
Surgical treatment is rarely necessary unless intra-articular pathology is present.  In patients with persistently painful iliopsoas symptoms surgical release of the contracted iliopsoas tendon has been used since 1984.

# Rehabilitation
Patients may require intermittent NSAID therapy or simple analgesics as they progress in activities.  If persistent pain caused by bursitis continues a corticosteroid injection may be beneficial.

## Physical Therapy
Both active and passive stretching exercises that include hip and knee extension should be the focus of the program. Stretching the hip into extension and limiting excessive knee flexion avoids placing the rectus femoris in a position of passive insufficiency, thereby maximizing the stretch to the iliopsoas tendon. Strengthening exercises for the hip flexors may also be an appropriate component of the program. Education, a non-steroidal anti-inflammatory drug regiment, as well as activity modification or activity progression (or both) may be used.  Once symptoms have decreased a maintenance program of stretching and strengthening can be initiated. Light aerobic activity (warmup) followed by stretching and strengthening of the proper hamstring, hip flexors, and iliotibial band length is important for reducing recurrences.
Conservative measures generally resolve the problem in 6 to 8 weeks.