by Brent Whitehead, OMSII
The hip joint is classified as a ball and socket joint, with the head of the femur (long bone of the thigh) being the ball and the acetabulum (indentation on the pelvis) being the socket. Normal movement of the hip joint is allowed through smooth gliding of the articular cartilage on the ball and socket as they move in coordination with each other. Generally speaking, “normal” anatomy leads to “normal” motion at the joint in question, using this as guide it is easy to see how hip impingement can occur if this normal anatomical motion is impeded caused by an anatomical deformity. Some of these include:femoral head or neck deformity or a hip socket deformity. The abnormal motion the joint is put through can cause uneven wearing of the joints cartilage, which in turn can lead to further damage of the hip. This damage may involve the labrum of the hip (acetabular labrum). Much like the labrum of the shoulder (glenoid labrum), the acetabular labrum is a cartilaginous ring around the rim of the hip socket that provides the joint with additional stability. The symptoms of a labral tear may mimic or even exacerbate the symptoms hip impingement.
Most patients complain of associated pain in the groin with prolonged movement or sitting, pain in the buttock, lower back, or along the lateral portion of the thigh. Other symptoms include stiffness or inability to achieve high levels of hip flexion, and occasionally painful popping or clicking in the front of the hip.
There are two generally accepted forms of impingement at the hip joint.
- The first, a CAM IMPINGEMENT: this is where the head of the femur (“ball” of the ball and socket) is not perfectly round and results in an abnormal articulation of the joint leading to accelerated damage to the articular cartilage.
- The other form is the PINCER DEFORMITY, as the name suggests, the head of the femur is “pinched” by the acetabulum. In this case, the socket covers too much of the ball which leads to banging of the ball into the rim of the socket during higher degrees of hip flexion and extension.
These two deformities can occur concomitantly, which is known as combined impingement.
The diagnosis of hip impingement is typically made after a thorough history and physical exam is performed. If your doctor is concerned that you have hip impingement, X-Ray images of the hip will be obtained to assess the general bony structures of the hip and their relationship to each other. Possible further analysis via magnetic resonance imaging (MRI) or computed tomography (CT scan) may be needed to better evaluate the bones, muscles, articular cartilage and labrum in more detail.
Your physician may suggest a myriad of treatment options to tackle your symptoms. As a first line treatment, rest, anti-inflammatory treatment, and physical therapy are normally used as a conservative options before moving onto more aggressive treatments, such as joint injections and surgical intervention; however, if left untreated hip impingement can lead to early onset osteoarthritis.
If you are experiencing any of these symptoms, consult one of our orthopedic hip specialists today! OrthoNeuro has 3 orthopedic surgeons who treat hip conditions.