Progression of Femoroacetabular Impingement in Contralateral Hip

New research has uncovered which factors are important when tracking the progression of disease in the contralateral hip of patients with symptomatic femoroacetabular impingement. FAI is one of the most common causes of hip osteoarthritis, but the factors controlling the progression of it are still not completely understood.

The study, “Factors Associated With Disease Progression in the Contralateral Hip of Patients With Symptomatic Femoroacetabular Impingement: A Minimum 5-Year Analysis,” was published online on August 26, 2022, in The American Journal of Sports Medicine.

The study enrolled 150 patients who underwent FAI surgery and had a minimum of five years of follow-up. Data measuring symptoms and surgical progression were collected for all patients.

Thirty-nine patients had contralateral hip symptoms at the initial evaluation. Of those without contralateral hip symptoms at initial evaluation, 32% (36/111) had developed contralateral hip symptoms by the time of the final follow-up.

The factors associated with disease progression included lower anteroposterior head-neck offset ratio (0.153 vs 0.165; p = .005), decreased total arc of rotation in 90° of flexion (39.9° vs 51.1°; p = .005), and decreased external rotation in 90° of flexion (28.6° vs 37.1°; p = .003) compared with those who never developed symptoms.

Age, sex, body mass index, alpha angle, lateral center-edge angle, internal rotation in flexion, and University of California, Los Angeles, activity score were similar between the groups. Those patients with contralateral symptoms at initial evaluation progressed to contralateral surgery at a rate of 41% and those who developed contralateral symptoms during the study period progressed to contralateral surgery at a rate of 28%.

Among all the patients with contralateral hip symptoms, younger patients (24.6 vs 34.1 years; p < .001) and baseline UCLA activity score ≥9 (p = .003) were associated with progression to surgery. By Kaplan-Meier analysis, 64%, 54%, and 48% of patients remained free of contralateral hip symptoms at 2, 5, and 10 years, respectively.

The researchers found that at mean follow-up of 7.1 years, 50% of the patients had significant symptoms in the contralateral hip.

So, in summary, the research team found evidence that disease progression was associated with decreased hip rotation arc, decreased external rotation, and decreased external rotation, and decreased head-neck offset ratio. They also discovered that younger age and UCLA activity score greater than or equal to 9 was associated with progression to surgery.

“The results of the study were not surprising as the prognosis for hips with FAI morphology are quite variable. We did anticipate a larger effect related to the severity of baseline hip deformity in symptom progression and need for surgery. Nevertheless, disease progression is multifactorial and future studies (with larger patient cohorts and longer follow-up) will identify the most important risk factors for FAI disease progression,” John C. Clohisy, M.D. of the Washington University School of Medicine, told OTW.

“There are no proven strategies to slow disease progression in the contralateral hip.”

“Recommendations regarding activity modification (avoidance of repetitive high hip flexion activities and cutting/pivoting sports) make sense, but many of these patients are very active/athletic and return to sport is a priority. Most important is patient counseling regarding the risk for disease progression in the contralateral hip and the advantages of hip evaluation at the onset of symptomology.”

Study authors included Adam Z. Khan, M.D., Wahid Abu-Amer, M.D., Susan Thapa, Ph.D., Frank W. Parilla, M.D., Cecilia Pascual-Garrido, M.D., Ph.D., John C. Clohisy, M.D., and Jeffrey J. Nepple, M.D., all from the Washington University School of Medicine in St. Louis, Missouri.