Relationship Between Age at Onset of Symptoms and Intraoperative Findings in Hip Arthroscopic Surgery

BACKGROUND: Hip arthroscopic surgery is intended to treat multiple abnormalities in an effort to delay the progression to osteoarthritis, especially in young patients. However, the length of time in which patients experience joint pain before seeking a specialist for a diagnosis can delay hip preservation surgery and influence clinical outcomes. PURPOSE: To investigate the relationship between age at symptom onset and findings during hip arthroscopic surgery as well as outcomes after 2 years of clinical follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: From February 2008 to March 2015, data were prospectively collected on all patients undergoing hip arthroscopic surgery at a single institution. Anatomic and pathological characteristics were recorded intraoperatively. The mean age at onset of symptoms was calculated and correlated with intraoperative findings using Pearson correlation and logistic regression. All patients were assessed preoperatively and postoperatively with 4 patient-reported outcome measures: the modified Harris Hip Score (mHHS), the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score–Activities of Daily Living (HOS-ADL), and the Hip Outcome Score–Sport-Specific Subscale (HOS-SSS). Pain was estimated using a visual analog scale (VAS). Furthermore, patients with an age at onset of symptoms below the mean (34.6 years) were compared with those of an age at onset of symptoms above the mean. The 2 groups were compared using the Student t test and the chi-square test. P values <.05 were considered significant. RESULTS: A total of 1697 patients met the inclusion criteria. Body mass index was weakly correlated with age (r = 0.3). Younger patients had a lower prevalence of combined Seldes type 1 and 2 labral tears; acetabular labrum articular disruption (ALAD) grade 2, 3, and 4 acetabular chondral lesions; and Outerbridge grade 2, 3, and 4 femoral head chondral lesions (P < .05 for all). More advanced age was correlated with wider labral tears and chondral lesions based on a clock face (r ≥ 0.2, P < .05). Patients younger than 34.6 years had a lower prevalence of gluteus medius and ligamentum teres tears (P ≤ .001). The prevalence of synovitis was positively correlated with age, while instability was negatively correlated with age (P = .04). The improvement of scores from preoperatively to 2-year follow-up in the younger patient group was 62.69 to 83.82 for the mHHS, 64.97 to 87.35 for the HOS-ADL, 43.46 to 73.37 for the HOS-SSS, 63.01 to 85.19 for the NAHS, and 5.61 to 2.53 for pain VAS. All score improvements were statistically significant (P < .001). Regarding the older patient group, the improvement of scores from preoperatively to 2-year follow-up was 58.55 to 78.27 for the mHHS, 57.59 to 79.66 for the HOS-ADL, 35.63 to 61.88 for the HOS-SSS, 55.28 to 77.55 for the NAHS, and 5.72 to 3.01 for pain VAS. All score improvements were statistically significant (P < .001). CONCLUSION: Of the multiple intraoperative findings in hip arthroscopic surgery, many are related to age at onset of symptoms. Although we found a statistically significant improvement in clinical outcomes in both groups after 2-year follow-up, apparently the less complex and smaller lesions observed in both the articular cartilage and the labrum of younger patients result in better outcomes compared with older patients.