You have six hip flexor muscles that work to bend your hip in the front. The most important are the iliopsoas, which consist of two muscles, the psoas major and iliacus, that are situated deep in the abdomen and the rectus femoris, part of the quadriceps muscles on the thigh. If the hip flexors lock up or lose strength, you might have an injury to those muscles or the hip joint.
Tip
Several conditions including snapping hip syndrome, a hip flexor strain or a labral tear may cause your hip to lock up or give out. Consult your doctor if you experience pain, weakness or locking up in the hip.
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Hip Flexor Strain
A hip flexor strain, when the muscles are torn or stretched, is an injury that may occur with sudden movements in the hip. This could include jumping, running and changing direction quickly or kicking.
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Depending on the severity of the strain, you may experience severe pain that prevents the hip from moving, spasms in the hip and weakness and difficulty straightening the hip when standing from a squat or seated position. Treatment includes rest, icing the injured area and over-the-counter pain and anti-inflammatory medications. Severe hip flexor strains may also require physical therapy.
Hip Bursitis or Tendonitis
Tendonitis and bursitis in the hip are usually caused by overuse and may make it difficult to move the hip joint and cause pain and swelling. Tendonitis is swelling and irritation of the tendons and bursitis is the inflammation of the bursa. These conditions can usually be treated successfully with rest, cold compress, anti-inflammatory medication and physical therapy.
Labral Tears in the Hip
A labral tear, a tear to the cartilage that surrounds the hip joint, has many overlapping symptoms with hip tendonitis and bursitis. In addition to pain and clicking in the hip, a labral tear may cause your hip to lock up.
Your doctor will diagnose the tear using imaging tests including MRI and X-ray. In severe cases, surgery may be required to repair the tear, but often the injury will heal with rest and physical therapy.
Snapping Hip Syndrome
Snapping hip syndrome is usually caused by overuse and is characterized by the audible popping sound you hear when you move the hip joint. It can be caused when the iliotibial band moves over the head of the femur or when the iliopsoas tendon moves over bony protrusions of the hip. Other symptoms include pain and weakness in the hip.
Your doctor can usually diagnose snapping hip syndrome with a physical exam, but additional imaging tests may be necessary to rule out other conditions. If you are not in pain, no treatment is needed. If you are experiencing pain or weakness, your doctor may recommend rest, stretching and physical therapy, anti-inflammatory medications or steroid injections in the hip.
Read more: How to Get Rid of Hip Flexor Pain
When Your Hip Gives Out
If you have severe arthritis or damage to the hip joint, and the pain becomes unmanageable, your doctor may recommend hip replacement surgery. Your doctor will confirm the damage to the hip with a physical exam, X-ray and other imaging tests.
Warning
While many conditions that cause the hip flexor to lock up and give out are treatable with rest, ice and over-the-counter medications, failure to properly treat the condition may cause further damage to the hip joint and surrounding tissue. If you experience pain in the hip, consult your doctor and follow the recommended treatment plan.