Hip Impingement – What is it? Why does it hurt? And how is it treated?
By Michael J. Huang, MD, Sports Medicine, Orthopaedic Surgeon at Colorado Springs Orthopaedic Group, Colorado Springs LIVING WELL Magazine
There are many sources of hip pain and the majority of people will suffer from it at one point or another in their lifetime. In most cases, pain in or around the hip is temporary and resolves on its own or with non-surgical management. However, there are some causes of hip pain that persist and may require surgical intervention. One diagnosis that is receiving more attention is hip impingement or femoroacetabular impingement (FAI).
The hip joint is typically thought of as a “ball and socket” joint (see figure 1). The “ball” or femoral head is the top of the femur (thigh bone) while the “socket” is the acetabulum (part of the pelvis). The hip joint is lined with cartilage. This is the slippery tissue that creates a smooth, low friction surface that helps the bones glide easily across each other. In addition, the acetabulum is ringed by strong fibrocartilage called the labrum, which forms a gasket around the socket, creating a tight seal and helps to provide stability to the joint.
In hip impingement, there is a mismatch between the femoral head and the acetabulum. There is either too much bone on the acetabulum or on the femoral head or both (see figure 2). In this situation, the bones on either side of the joint will collide or impinge repeatedly. When there is too much bone on the femoral side, this is referred to as cam type impingement whereas too much bone on the acetabular side is called pincer type impingement. Of course, a patient could have a component of each type of impingement. This situation can result in tearing of the labrum, cartilage, or both.
People with hip impingement usually have pain in the groin area, although the pain sometimes may be more toward the outside of the hip. Sharp, stabbing pain may occur with turning, twisting, and squatting, but sometimes, it is just a dull ache. In addition to pain, patients will typically experience stiffness or loss of motion over time. Usually, pain from hip impingement is worsened in the sitting position or hip flexion position.
The diagnosis of hip impingement is made with a standard physician office visit, x-rays, and usually an advanced imaging test that may include MRI. As part of the physical examination, your doctor will likely conduct the impingement test. For this test, your doctor will bring your knee up towards your chest and then rotate it inward towards your opposite shoulder. If this recreates your hip pain, the test result is positive for impingement. Specialized X-ray views of the pelvis/hip joint can show whether your hip has abnormally shaped bones consistent with hip impingement. In addition, x-rays can show signs of arthritis in the joint. Magnetic resonance imaging (MRI) scans can create better images of soft tissue and can identify damage to the labrum and/or articular cartilage. Injecting dye into the joint (arthrogram) during the MRI may make the damage show up more clearly. Your doctor may also inject a numbing medicine into the joint as a diagnostic test.
Treatment for hip impingement (FAI), labral tears, and cartilage damage typically fall into two categories: non-surgical treatment and surgical treatment. Non-surgical treatment includes: modifying or avoiding activities that increase symptoms, using anti-inflammatory medication, and physical therapy to improve range of motion in the hip and strengthen the musculature around the hip. Surgical treatment is typically used for patients that have failed non-surgical treatment options. The goal of surgery is to remove the excess bone around the hip joint (correct the impingement) and treat or repair a labral tear and address any cartilage damage. Surgery can be done both in an open fashion (with a standard larger incision) or arthroscopically (minimally invasive). Over the past several years, there has been significant technological advancement that allows surgeons to treat this complex hip problem arthroscopically. Performing the surgery in this fashion addresses the problem with as little surgical trauma as possible and provides for a faster recovery and rehabilitation.
Surgery can successfully reduce symptoms caused by hip impingement. Correcting the impingement can prevent future damage to the hip joint. However, not all of the damage can be completely fixed by surgery, especially if treatment has been put off and the damage is severe. It is also possible that more problems may develop in the future.
Michael J. Huang, MD, is a sports medicine orthopaedic surgeon at Colorado Springs Orthopaedic Group and may be reached at 719-574-8383.
