CORR Insights®: Acetabular Labral Tears Are Common in Asymptomatic Contralateral Hips With Femoroacetabular Impingement

Where Are We Now?

As the field of hip preservation continues to grow, so does the need for fine-tuning of the preoperative evaluation and patient-selection processes. To make good surgical recommendations, clinicians must integrate the clinical evaluation with objective radiographic findings.

The study by Vahedi and colleagues [12] provides us with further corroboration for a known phenomenon, the presence of positive imaging findings in asymptomatic hips. In the study, they found a labral tear in approximately 40% of asymptomatic hips, as well as chondral damage in approximately 15% of hips. In addition, while previous studies have found abnormalities suggestive of impingement and related pathologies in asymptomatic individuals [1, 2], Vahedi and colleagues [12] found that this also commonly occurs in individuals in whom one hip is symptomatic, and the contralateral hip, with similar MRI findings, is asymptomatic. Lastly, while the study only provided short-term followup, it does show that at 2 years, 21% of the asymptomatic labral tears will become symptomatic [12].

The presence of apparently abnormal imaging findings in asymptomatic patients is well-known in joints other than the hip as well. In the shoulder, labral tears are observed in 55% to 72% of middle-aged, asymptomatic patients [9]. In the knee, a stark discordance has been shown to exist between radiographic evidence of arthritis, and patient-reported pain and function [4]. Meniscal tears are found in 23% of asymptomatic nonarthritic knees and in 60% of asymptomatic knees with radiographic evidence of arthritis [3]. Such imaging findings have led to increasing rates of arthroscopic meniscectomies [6]. In the hip, labral tears and acetabular damage are known to exist in asymptomatic patients, with an apparent prevalence of more than 50% [5, 11].

We are unaware of what the prognostic implications are for most of these imaging findings in asymptomatic patients. However, in certain situations, we have at least some sense for those lesions that are at risk for progression, and hence, we can make a recommendation for preventive treatment. For example, in cases of bilateral osteonecrosis of the femoral head when a patient is treated for a symptomatic lesion, and an asymptomatic contralateral lesion is found that is medium-sized or larger, preventive treatment has been recommended [7]. In patients in whom the clinical importance of a lesion is unknown, such as labral tears in the hip, preventive treatment cannot be justified. On the other hand, when the risk of developing symptoms in this hip is 21%, the patient should be informed and advised to report back if symptoms develop.

Where Do We Need To Go?

Management of each patient should rely on three important factors. First, an individualized understanding of each patient’s underlying conditions, and the functional level that each patient wishes to achieve. Second, an understanding of the pathological process causing the patient’s symptoms (or the likelihood of developing symptoms in the event the patient has an asymptomatic finding on imaging tests), and the long-term implications of the condition in question. And finally, an appreciation of whether surgery can improve on the natural history of the condition each patient has.

The future of orthopaedic surgery in general, and hip arthroscopy in particular, involves adapting management and surgical treatment, and personalization based on unique circumstances of an individual patient. While two patients might have the same objective findings, no two patients are the same, and so all decisions to intervene must be individualized.

Studies like those of Vahedi and colleagues [12] remind us that we need more and better information about which imaging findings are likely to cause symptoms or harm, and which are unimportant. Those authors emphasized, correctly in my opinion, that even in the same patient, two hips with similar findings may “behave” differently. Future studies should help us understand why this is.

Finally, in addition to the need to individualize care to the findings and goals of each patient, we need better information on the longer-term implications of hip-preserving treatments. Some orthopaedic interventions seemed promising at short-term followup, only to prove disappointing later on.

How Do We Get There?

The shift to personalized medicine, which involves decision-making based on the unique characteristics of each specific patient, is the next step in improving results of our treatments. Several recent studies in the field of hip arthroscopy [8, 10] have created predictive algorithms and models to predict patient-reported outcomes as well as the risk of hip preservation failure. We recently published a model based on pre and intraoperative findings to predict risk of conversion of an arthroscopic labral repair to a THA [8]. We found a number of significant risk factors, including increasing age, lower preoperative modified Harris hip score, decreased femoral anteversion, decreased lateral center-edge angle, revision surgery, and grades of femoral and acetabular chondral damage. Future studies might enhance these attempts and create more robust models, especially ones focusing on preoperative data, in order to better define the appropriate candidate for hip preservation surgery.

This refined understanding needs to occur also in understanding the different pathologies of the hip. The prognosis and natural history of femoroacetabular impingement, labral tears, and other intra-articular pathologies, such as ligamentum teres tears, still need to be better defined. Longitudinal studies, showing the natural history and disease progression over decades, will provide us with data regarding risk of progression to hip arthritis, the likely outcome for a specific patient, as well as the effect a specific treatment has on that disease progression. Registry studies can provide important data on epidemiology and long-term effects of the various treatments, as well.

Finally, treatment itself can be increasingly personalized using technology such as navigation and robotics. Just as in the fields of spine surgery and joint reconstruction, adaptation of navigation, robotics, and other advanced technology may lead to higher accuracy and improved patient-reported functional outcomes and native joint survivorship.