Snapping hip (coxa saltans)
The clicking sensation may be due to the iliotibial band sliding anteriorly over the femoral trochanter (external snapping)

Definition

A snapping hip syndrome consists in a sound or crack sensation arising during hip motion.

The psoas major and iliac muscle whose ligament surrounds the femoral head cause internal snapping

Pathology

A snapping hip is the snap or click caused by the movement of the muscles and tendons around the hip joint. This is felt while walking, running, getting up or when swinging the legs backwards. With hip flexion the iliotibial band moves from the posterior to the front side of the great trochanter producing the snapping sensation. It is a frequent pathology in young athletes and dancers and is often named dancer’s hip. The pathology can be associated with other hip conditions such as the trochanteric bursitis and iliotibial tendinitis.

X-rays are used to visualise free fragments released in the joint and any damage to the cartilage and bones

Classification

Three distinct types of this pathology have been characterised:

External snapping hip occurs when the hip iliotibial band slides over the great trochanter

Internal snapping hip is the most frequent form and occurs when the iliopsoas tendon slides over the femoral head, prominent iliopectineal ridge exostoses of lesser trochanter and iliopsoas bursa

Intraarticular snapping hip occurs due to the presence of free fragment(s) in the hip joint (e.g. synovial chondromatosis, tear or fracture of bone and cartilage) or in association with labral tears

 External snapping hip may be the consequence of:

-  Thickened the iliotibial band at the posterior side or near the insertion with the gluteus maximus; During hip flexion the band skips anteriorly over the greater trochanter

-  Tightness of the iliotibial band that is caught when sliding over the greater trochanter during hip flexion, adduction or internal rotation

-  Iliopsoas tendon sliding over the lesser trochanter

Left: Distal radius intraarticular, displaced fracture; Middle: Older distal radius fracture with callus formation; Right: Distal radius and ulna fracture, extraarticular and displaced

No 2.

Intra-articular fracture extends to the wrist joint (or articulation)

Extra-articular fracture is located outside of the wrist joint

Open fracture when bone fragments perforate the skin

Comminuted fracture when the bone breaks into multiple fragments

Non-displaced when the anatomical alignment of the bone is maintained or displaced when the bone fragments move apart.

Melone’s classification describes the characteristics of intra-articular fractures of the radius:

i    Stable fracture

ii    Unstable "die-punch"

iii   "Spike" fracture

iv Split fracture

v   Explosion injuries

Acetabular fracture of the pelvis

Acetabular fractures

These fractures are divided into:

Anterior pillar (not weight bearing part of joint)

Posterior pillar (often associated with dislocation of the hip including the weight bearing part of joint)

Transverse

Comminuted involving both column type 

Sacral / coccygeal fractures

The sacrum is a triangular-shaped bone formed by 5 fused vertebrae, which provide a posterior wall to the pelvic ring. At each side of the sacrum, the ala structures articulate with the ilium bones forming the sacro-iliac joints. Sacral fractures are usually parallel to the spine and can involve the ala. Less frequently sacral fractures may display an “H” shape, including a transversal fracture uniting both sides of the sacrum. Three zones are described where sacral fractures can occur that are along vertical lines relative to the alignment of the foramina. Sacral fractures may result in sacral instability and require treatment via sacroplasty (injection of bone glue into the fracture). Surgery is necessary in case of associated neurological symptoms.

Fractures of the coccyx involve the tailbone, the terminal portion of the spine situated below the sacrum formed by 3 to 5 fused vertebrae. Coccyx fractures occur when falling on a seated position. They are more common in elderly women and seldom require surgical treatment.

A hip fracture can cause a snapping hip

Causes

There is a number of causes leading to a snapping hip syndrome, however the exact pathology remains poorly understood. The main causes are:

Intense physical activities involving hip flexion and external rotation of the femur (dancing, athletics)

Excessive/repetitive training

Muscle tightness

Hip labral tear

Fracture of the hip

Cartilage rupture in the hip joint

Synovial chondromatosis

Young dancers have an increased risk for the pathology due to their extreme hip movements

Risk factors

Leading risk factors for a snapping hip include:

Age between 15-40 years performing intense sport

Excessive or inadequate training

Ballet dancers

Runners

Hip fracture or other hip degenerative conditions

Biomechanical characteristics (narrow iliac band, greater hip abduction, decreased external rotation, and greater strength in the external rotators of the hip)

Typically a click noise is heard when walking or with other movements

Symptoms

The main symptoms of snapping hip syndrome include:

Audible snap or clicking noise with hip movement

Pain only rarely

Pain radiating along the outer thigh (iliotibial band)

Pain to the anterior groin region (iliopsoas tendon)

Pain in anterior hip enhanced with activity

Ober's test is used to diagnose iliotibial band tightness

Diagnosis

The clinical examination begins with medical history to acquire information on activities and conditions that may have caused a snapping hip. Usually medical examination is sufficient for the diagnosis of a snapping hip.  External snapping is visible whereas internal snapping is mostly detected by the noise produced. The examiner places the hand on the great trochanter whilst the hip is flexed. This pressure prevents the snapping noise to occur in supports of the diagnosis. An internal snapping hip is diagnosed by moving the hip from a flexed/external rotation to an extended/internal rotation, resulting in the snapping characteristics. 

The Ober’s test is useful to detect tightness of the iliotibial band. Tenderness may manifest with palpation of the affected areas. Ultrasound allows to demonstrate the snapping of the iliotibial band during motion and is also used for therapeutic steroid injection. X-ray is only taken to rule out any degenerative changes of the hip joint (e.g. synovial chondromatosis) that may contribute to the pathology. Similarly, an MRI is used to detect associated pathologies of the bursa and iliopsoas tendon.

*Synovial chondromatosis = abnormal growth of the synovium, a membrane surrounding any joint capsule, producing cartilage nodules that become loose within the joint

Treatment

Local injection of steroids alleviates prolonged symptoms of a snapping hip

Nonoperative treatment

If a snapping hip syndrome does not produce pain no therapy is recommended. The management of a snapping hip is mostly achieved via conservative treatment, which also includes a biomechanical assessment and gait analysis to correct any dysfunctions. This approach involves:

Anti-inflammatory therapy with NSADs

Ice applications

Local steroids injection

Reduction and modification of physical activity

Physiotherapy

Z-plasty is a surgical procedure used to release a tight iliotibial band

Surgical treatment

Surgery is recommended only rarely when conservative therapy fails to resolve a snapping hip or in case of associated pathologies such as trochanteric bursitis and labral tear. Hip arthroscopy is often the method of choice. The surgical approaches share similarities to trochanteric bursitis but differ in case of external and internal snapping hip.

External snapping:

Partial release of the posterior iliotibial tract near the insertion to the gluteus maximus and excision of the trochanteric bursa

Partial resection of the iliotibial band above the greater trochanter and removal of the trochanteric bursa

Z-plasty of the iliotibial band to lengthen the tendon

Internal snapping hip:

Partial resection of the iliopsoas tendon

Removal of the prominence of the lesser trochanter

Complete severing of the iliopsoas tendon (may cause reduced hip motion)

Strengthening gluteal muscles (top), stretching hip flexors (bottom left) and quadriceps (bottom right) is part of rehabilitation of a snapping hip

Rehabilitation

Physical therapy is required during conservative and after surgical treatment. It aims at restoring flexibility of the iliotibial and iliopsoas tendons and strengthening the gluteal and thigh muscles. After surgery it is advised to avoid hip flexion for 6 weeks.

Physiotherapy treatment includes:

Rest

Ice treatment

Anti-inflammatory therapy (NSAIDs)

Manipulation

Massage

Stretching (quadriceps, piriformis, hamstrings, iliotibial band)

Activity modifying regime

Return to activity plan

Pilates is a recommended practice to prevent snapping hip or other hip pathologies

Prevention

The goal for prevention of snapping hip syndrome is maintenance of good flexibility and strength in the hip and pelvis:

Maintain strength of the hip muscles, pelvic muscles and buttocks

Maintain flexibility of muscles and tendons around the hip

Improve mobility of the hip joint

Reduce extreme sport