Intra-articular Hip Disorders in the Military Population

Incidence of Symptomatic Femoroacetabular Impingement: A 4-Year Study at a National Collegiate Athletic Association Division I Institution

Background:

Femoroacetabular impingement (FAI) is an increasingly recognized cause of hip pain in young athletes. Although there are multiple studies that describe the radiographic prevalence of FAI in athletes, its true incidence within this population is unknown.

Purpose:

To report on the overall and sport-specific incidence of symptomatic FAI in National Collegiate Athletic Association (NCAA) Division I athletes. Return-to-sport times were reported for patients treated operatively.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective review was conducted to identify all reported hip injuries within a large, multisport NCAA Division I institution. Hip injuries were stratified into FAI, general pain/dysfunction, musculotendinous, ligament, bursitis, bone stress, contusion, and other. FAI was diagnosed based on history, physical examinations, imaging, and symptomatic relief after a diagnostic injection. Descriptive statistics were used to calculate the overall and sport-specific incidence, and chi-square analysis was performed to identify contingency data.

Results:

In a 3-year period, a total of 5319 musculoskeletal injuries occurred in 1072 athletes. There were 491 (9.2%) hip injuries that occurred in 288 athletes, of which 40 injuries were FAI. The overall incidence of symptomatic FAI was 3.0% of the total population, 3.7% of all injured athletes, and 13.9% of athletic hip injuries. There were no statistically significant differences in FAI rates among male and female athletes overall or among male and female athletes within similar sports. Of the 19 athletes who were treated nonoperatively, 2 failed to return to play: 1 secondary to multiple musculoskeletal injuries and 1 related to cardiac issues. There were 21 hips in 20 patients that were treated operatively, with 1 athlete failing to return to sport. Return to play occurred at a mean of 202 days (range, 81-360 days) after hip arthroscopic surgery.

Conclusion:

In this large, multisport NCAA Division I cohort, the overall incidence of symptomatic FAI was 3.0% and represented 13.9% of hip injuries. The successful management of FAI with return to play was achieved by both nonoperative and operative treatment methods. The relatively low incidence of symptomatic FAI, despite reports of a high prevalence of FAI morphology in athletes, serves to emphasize the importance of clinical evaluations in treating patients with FAI.

Hip Strength Before and After Arthroscopic Femoroacetabular Impingement Surgery

Femoroacetabular impingement (FAI) and labral pathology are associated with pain, decreased function, and hip strength deficits. Existing data are in conflict regarding when hip strength normalizes following arthroscopic treatment of FAI. The objective of this study was to identify preoperative hip strength relative to the contralateral hip not undergoing surgery as well as when postoperative strength in 4 functional muscle groups normalizes following arthroscopic treatment of FAI. Ninety-eight individuals with radiographic evidence of FAI and labral pathology underwent arthroscopic labral repair. Pre-surgical hip strength testing was performed in the symptomatic "surgical hip" and the contralateral "non-surgical hip." Hip strength measurements were repeated at 8 and 16 weeks postoperatively. Significant preoperative hip strength deficits were noted in the surgical hip compared with the non-surgical hip in flexion, extension, and adduction. At 8 weeks postoperatively, hip strength in the surgical hip improved to being equivalent to that in the non-surgical hip in adduction and extension, remained equivalent to that of the non-surgical hip in abduction, and decreased in flexion relative to the non-surgical hip. At 16 weeks, hip strength remained equivalent in the surgical hip and the non-surgical hip in abduction and adduction, but the surgical hip exceeded the non-surgical hip in extension. While flexion strength improved between 8 and 16 weeks postoperatively for the surgical hip, it had not fully recovered to that of the non-surgical hip. Using a structured postoperative rehabilitation protocol, abduction strength was maintained at 8 weeks postoperatively, while adduction and extension strength had improved to those of the non-surgical hip. At 16 weeks postoperatively, hip abduction and adduction had strength equivalent to those of the non-surgical hip. Despite preoperative improvement, flexion of the surgical hip lagged behind that of the non-surgical hip 16 weeks postoperatively. [Orthopedics. 2021;44(3):148-153.].

Joint Space Narrowing in Patients with Femoroacetabular Impingement: A Matched Cohort Study of Military versus Civilian Patients

Introduction

Decreased hip joint space has been associated with poorer outcomes after hip arthroscopy. The purpose of this study was to determine if a difference exists in hip joint degenerative findings in military versus civilian patients with FAI.

Methods

A single surgeon’s case series was reviewed to identify all patients undergoing primary hip arthroscopy for treatment of FAI. All active duty military personnel were included in the study group. A cohort of civilian patients matched for age, gender, lateral center edge (LCE) angle, and alpha angle was identified and included as the control group. The hip joint space was measured at the medial and lateral extents of the acetabular sourcil and the center of the sourcil. The Tonnis grade for osteoarthritis was recorded for each patient. Labral tear size as well as femoral head and acetabular chondromalacia grading were obtained from operative records.

Results

A total of 229 patients that underwent primary hip arthroscopy for FAI were identified. 46(20.1%) were active duty military personnel. A well-matched cohort of 46 civilian patients was identified. There was no statistical difference in age (35.0, 34.7 years), gender (31 males, 15 females in both groups), BMI (26.8, 27.6), LCE angle (31.0, 31.5), and alpha angle (64.9, 64.9) between the civilian and military groups. Joint space was narrower in the military group in each of the three measured locations (Superomedial 3.8 mm vs 4.2 mm, p = 0.025; Superior 4.0 mm vs 4.4 mm, p = 0.013; Superolateral 4.4 mm vs 4.9 mm, p = 0.043).

Conclusion

Military patients with FAI may have increased joint space narrowing compared to otherwise similar civilian patients. Femoral and acetabular chondromalacia are found in similar frequencies in military and civilian populations, however the grading system utilized accounts for the presence but not the size of high grade lesions.

Level of Evidence

Level 3.