It is now well established in the literature that patients with anatomical abnormalities of the hip joint develop symptoms in a large proportion of cases. What has not been fully understood is whether specific anatomical parameters can predict the onset of symptoms in a healthy individual.
A recent paper published in the American journal “American Journal of Sports Medicine” attempts to answer this question. The study hypothesis was that specific parameters of the anatomy of the femur and the acetabulum can predict whether a patient will become symptomatic in the future.
The study included 548 participants, comprising 176 symptomatic patients who were scheduled for hip surgery or had functional restriction of the joint, and 372 asymptomatic volunteers who underwent three-dimensional magnetic resonance imaging. Multiple measurements were recorded for the femur (alpha angle, omega angle, neck-shaft angle and torsion) and the acetabulum (version, coverage), as well as spinopelvic measurements. All of these parameters were measured semi-automatically.
The symptomatic patients had larger cam-type lesions (as defined by the omega and alpha angles), less acetabular coverage, greater pelvic incidence and greater sacral slope. The patients had higher values for the spinopelvic measurements than the asymptomatic volunteers. When these parameters were entered into a logistic regression, a significant degree of prediction emerged for the symptomatic patients with abnormal morphology.
The authors concluded that there is a complex dynamic interaction between the hip and the spinopelvic measurements. Measurements such as femoroacetabular impingement of the cam type, reduced coverage of the femoral head by the acetabulum and increased spinopelvic angles are predictive factors for a symptomatic hip. These measurements were important in identifying the symptomatic individual among the study participants, and were important in combination with other abnormalities of the hip. Symptomatic patients can therefore be effectively distinguished from asymptomatic volunteers on the basis of anatomical predictors.
Source: “American Journal of Sports Medicine”, October 2018
