Another male–female presentation difference involves symptom bilaterality. Specifically, males are significantly more likely than females to have symptomatic FAI involving both hips. In a recent study of 646 patients who underwent hip arthroscopy for symptomatic FAI during a 2-year period, Klingenstein and colleagues8 found that females constituted 48.2% of unilateral arthroscopy patients but only 34.8% of bilateral arthroscopy patients. The odds ratio of males treated for both hips, compared with females, was 1.7 (95% confidence interval, 1.16–2.54).
Last, it has been reported that, on clinical presentation, hip function scores are significantly lower in females than in males. In a recent study of 612 cases of symptomatic FAI treated with hip arthroscopy, Malviya and colleagues9 found that females had significantly lower quality-of-life scores both before and after surgery. Hetsroni and colleagues7 reported similar findings, with females having significantly lower preoperative modified Harris Hip Scores and lower Hip Outcome Scores in the domains of Activities of Daily Living and Sports.
Sex-Based Differences in FAI Treatment
and Outcomes
Surgical treatment of FAI is focused on identifying the source of hip pain and dysfunction—be it osseous lesion, labral tearing, chondral injury, or iliopsoas tendonitis—and treating it accordingly, regardless of sex. Most studies of this approach find consistent improvement in the short-term and midterm outcome scores for a majority of patients. However, relatively few studies have focused specifically on sex in determining the percentage of patients who require surgical treatment, in deciding the type of surgery that should be performed, or in measuring surgical outcomes in patients with symptomatic FAI.
In their review of 23 studies of FAI surgery, Ng and colleagues10 found that, of 970 patients, 608 (62.7%) were male and 362 (37.3%) were female. Similarly higher rates for males were previously published.5,11 More recently, Clohisy and colleagues12 reported on the descriptive epidemiology of patients having surgery for FAI at 8 different medical centers in North America. Fifty-five percent of the hips surgically treated for symptomatic FAI were females’. The authors speculated that this unexpectedly high rate could have resulted from US and Canadian female athletes’ increasingly higher level of sports participation. The results of this study, one of the largest examining the rate of surgery for males and females with FAI, suggest that females are more likely to have surgery for symptomatic FAI despite being less likely to have radiographic evidence of impingement. Our understanding of this phenomenon continues to advance.
In a recent prospective study, Krych and colleagues13 evaluated the clinical outcomes of FAI surgeries (labral débridement, labral repair) in an all-female patient cohort. Female patients with symptomatic FAI were randomized to undergo either labral débridement or labral repair. There were clinical improvements in both groups, but, compared with labral débridement patients, labral repair patients had more significantly improved Hip Outcome Scores in the domains of Activities of Daily Living and Sports, as well as better subjective outcomes. Although the study did not compare female patients with male patients, it does provide evidence that female patients specifically may benefit more from labral repair than from labral débridement alone.
With respect to different surgical treatments for male and female patients, Hetsroni and colleagues7 introduced the idea of sex-specific treatment when they noted more hip anteversion in their study’s female patients than in its male patients. They suggested that, because the anterosuperior acetabulum is subjected to a high amount of stress during weight-bearing and gait, this area in females with suspected pincer lesions should be rim-trimmed judiciously to avoid increasing the stress and perhaps even hastening the development of degenerative disease. Last, though several authors have noted that hip function scores are lower in females than in males on presentation, it has also been reported that females demonstrate more improvement in functional scores after surgery.9 This may be important information to discuss during preoperative counseling about expected goals and outcomes.
Conclusion
Femoroacetabular impingement is a common clinical entity that affects both males and females. However, sexual dimorphism in FAI incidence, presentation, treatment, and outcomes has recently been described in the literature (Table). Being aware of these sex-based differences and tailoring patient evaluation and management accordingly will likely result in optimal outcomes for each person who presents with symptomatic FAI.
