The hip plays an important role in supporting the upper body weight while standing, walking, running, and hip stability is vital for these functions. The femur (thighbone) and acetabulum (hip bone) join to form the hip joint, while the labrum (tissue rim that seals the hip joint) and the ligaments lining the hip capsule maintain the stability of the hip. Injury or damage to these structures can lead to a condition called hip instability. Hip instability happens when the hip joint becomes unstable causing various symptoms.
The most common symptoms of hip instability include:
- Sensation of the hip “coming out” of the socket
- Producing a clicking sound
Hip instability can be traumatic or atraumatic in origin. Traumatic injury can be caused by injuries from sports or motor vehicle accidents. These injuries can damage the bony structures, labrum, and cartilage of the hip joint and can form loose bodies in the joint that can cause further damage. Atraumatic instability can be caused by overuse or developmental/congenital abnormalities of the hip joint.
Conditions that can cause hip instability include:
- Labral and ligament tears
- Hip dysplasia (undercoverage of the acetabular socket)
- Femoroacetabular impingement (abnormally shaped bones of the hip joint)
- Tears to the ligamentum teres
Diagnosis is includes a detailed medical history and physical examination. Imaging studies such as X-rays, CT and MRI Arthrogram scans may be used to confirm the diagnosis of instability. Special physical exam tests for instability including posterior impingement tests and dial tests may be performed.
Conservative treatment is usually the initial approach including protected weight bearing (use of cane, crutch or walker), and referral to a physical therapist for specific muscle strengthening and range of motion exercises.
If conservative treatment fails to resolve symptoms, or if there is a large fracture or loose bodies present, you may be recommended for surgical treatment. Surgery can be arthroscopic (minimally invasive) or open depending on your condition. Most of the common causes of hip instability, such as damage to the hip capsule and ligaments surrounding the joint, and labral tears can be treated arthroscopically. Your orthopedic hip specialist will be the best person to evaluate your symptoms and address your instability.