Cartilage defects in the hip may result from an acute traumatic event or chronic degeneration due to overuse of the hips joint. They can become a significant cause of pain in the hip. Left untreated, cartilage defects continue to worsen over time, a process known as arthritis.

The hip is a "ball-and-socket" joint. In a normal hip, the ball at the upper end of the thigh bone (femur) fits firmly into the socket, which is part of the large pelvis bone. In babies and children with developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose in the socket and may be easy to dislocate.

The gluteus medius is one of three muscles in the buttock and is situated on the outer surface of the hip. The gluteus medius assists with pelvic stability, hip abduction (leg separation) and internal/external rotation of the hip.

Femoroacetabular impingement (FAI), also known as hip impingement, is a mechanical or structural disorder of the hip. It can occur in people of all ages, including adolescents and young adults. In the healthy hip, the rounded top of thigh bone (femoral head) “plugs into” the hip socket (acetabular socket) in such a way that the femoral head can move smoothly within the socket.

he hip plays an important role in supporting the upper body weight while standing, walking and running. The stability of the hip is crucial in order to perform these functions seamlessly and without pain. The femur or thigh bone and acetabulum (hip bone) join to form the hip joint. The labrum, the tissue rim that seals the hip joint, and the surrounding ligaments that line the hip capsule maintain stability.

The iliotibial band is the tendon attachment of hip muscles into the upper leg (tibia) just below the knee to the outer side of the front of the leg. Where the tendon passes below the knee, there is a bursa sac between the bone and tendon. This tendon moves over the knee and the bursa acts as a buffer to reduce friction.

A loose body is a small piece of cartilage or bone that breaks off the hip joint and is floating within the joint. It can be the result of a hip injury, such as a fall, automobile accident, or a sports-related injury. Loose bodies can also occur as the result of long-term wear and tear to the hip joint

The labrum is a fibrocartilage rim that surrounds the hip joint and gives it stability. The fibrocartilage deepens the socket, seals the joint and protects it by decreasing impact. A tear to the labrum can cause pain in the front of the hip, in the groin or side of the hip.

The hamstrings are a group of four muscles on the back (posterior) part of the thigh (femur), which are important for hip extension and knee flexion. The four muscles include the semitendinosus, semimembranosus and the long and short head of the biceps femoris.

The piriformis muscle is a pear-shaped muscle in the buttocks that extends from the base of the spine to the top of the thigh. Tightness in this muscle can compress the sciatic nerve.The sciatic nerve is the largest nerve in the body. It extends from the lower spine down to the foot. Piriformis syndrome is a neuromuscular condition which can cause posterior hip pain, deep buttock pain and even shooting pain down the back of the leg.

In a snapping hip, a tight iliopsoas tendon “pops” over top of the femoral head, the iliopectineal eminence and labrum. The “popping” may produce a loud sound, and may cause a sensation that the hip is popping out of its socket or dislocating. In many cases, flexing and extending the hip when walking, sitting or standing can reproduce the snapping.