The Utility of Medical Imaging for Hip-Related Groin Pain
A recent editorial questions the growing reliance on advanced imaging findings as the main criterion for surgery
Femoroacetabular impingement syndrome occurs when an extra bone -- known as a bone spur -- grows along one or both of the bones that form the hip joint. The irregular shape causes unwanted friction within the ball-and-socket joint, which can lead to tears in the surrounding cartilage and pain in the groin area.
Recent technological advances in medical imaging have allowed the vast majority of physicians to use CT or MRI results when diagnosing patients with femoroacetabular impingement syndrome. Some of these patients then undergo a surgical procedure called hip arthroscopy to repair the cartilage and trim any bone spurs.
However, some experts question this reliance on imaging findings as the main criterion for surgery. An international team of physicians have written an editorial recommending a more careful interpretation of imaging results when it comes to hip-related groin pain. While hip imaging and arthroscopy rates have grown rapidly, improved clinical outcomes haven't necessarily followed suit, possibly pointing to alternative causes for groin pain. The paper was published in the May issue of the British Journal of Sports Medicine.
“We do not treat isolated joints of the body. We treat people, and their pain. Pain is influenced by many things -- activity levels, sleep, stress, mental health -- and not just what we see on a scan,” said first author Kieran O'Sullivan, lead physiotherapist of the Sports Spine Centre at Aspetar and Senior Lecturer at the University of Limerick in Ireland. “Therefore, it is important that we treat the human, not the scan.”
O'Sullivan and his colleagues stress that imaging findings do not always correlate with pain. Results which appear clinically significant may in fact be benign or even protective. For instance, a 2015 meta-analysis of 2,114 asymptomatic individuals with MRI and/or CT found that 37 percent had a cam deformity, or an excess of bone along the upper surface of the femoral head, and 67 percent had a pincer deformity, or an extra bone extending out over the rim of the hip socket.
In the past, physicians noticed that patients with low back pain had anatomic abnormalities in clinical scans. But after further studies, they realized that many pain-free individuals had the same distinguishing features. Today, doctors should generally avoid CT or MRI imaging in patients with nonspecific low back pain in the absence of progressive neurologic deficits or other red flags. O'Sullivan fears that doctors assessing hip and groin pain could be going down the same misguided path.
“For persistent hip and groin pain, people should not rush for a scan," he said, "We are not always sure what is abnormal."
Instead, he emphasizes caution before advising patients to undergo any type of therapy on the basis that it will prevent further problems, particularly if the treatment offered has significant risks (e.g., radiation, surgical infection) or high costs (e.g., surgery).
However, not everyone agrees with all the points made in the editorial. Alexander Weber, a specialist in the field of orthopedic surgery and sports medicine at the University of Southern California who was not involved with the editorial, agrees that MRI scans may be too frequently ordered.
“Much of the diagnosis and treatment recommendations can be made based on accurate history, thorough physical examination, and plain radiographs of the affected hip and pelvis,” said Weber.
But he believes that strong evidence exists for hip arthroscopy as a superior management approach. Several large studies have demonstrated the longevity and utility of the procedure for femoroacetabular impingement syndrome.
“Injured athletes that are unable to perform due to debilitating hip symptoms are able to return to their competitive sport of choice [after hip arthroscopy],” said Weber. “The average return to sport rate is in the low- to mid-90 percent of athletes, depending on the study. Many are able to reach new levels of participation (i.e., go from high school to collegiate or collegiate to professional) thanks to hip arthroscopy and its ability to alleviate pain and increase hip function.”