Background/Objectives: To determine whether patients under 30 years of age who have experienced symptoms for a duration of less than 1 year before undergoing hip arthroscopy (HA) for femoracetabular impingement (FAI) have better patient-reported outcomes than patients aged 40 years or older who have experienced symptoms for a duration of more than 1 year. Methods: This is a single-center, single-surgeon, retrospective analysis performed between August 2007 and May 2023 analyzing patients who underwent hip arthroscopy. Patients were divided into those who were 18 to 30 years old and patients that were 40 years and older. All patients who underwent primary hip arthroscopy for FAI and had completed mHHS or NAHS surveys prior to surgery with at least a 2-year follow-up were initially included in the study. Patients were excluded if they had no symptom duration information documented in their electronic medical record, a history of inflammatory arthritis, previous ipsilateral hip surgery, or future conversion to total hip arthroplasty (THA) before final follow-up. Results: A total of 236 hip arthroscopies were analyzed, including 147 patients ≥40 years and 89 patients 18–30 years, with symptom duration being significantly longer in the older cohort (28.4 vs. 17.5 months, p < 0.001). At 2 years, there was no difference in mHHS or NAHS between groups; however, younger patients with shorter symptom duration were more likely to achieve PASS for NAHS (87.5% vs. 58.7%, p = 0.036). At 5 years, the older cohort showed greater improvement in mHHS (33.1 vs. 22.9, p = 0.048), while patients 18–30 years continued to demonstrate higher absolute mHHS and NAHS at both 2 and 5 years. Regression analysis confirmed that increasing age was associated with lower PROs at follow-up. Conclusions: There was a significantly greater number of patients who achieved PASS for NAHS at 2-year follow-up for patients who were 18–30 years old with symptom duration ≤ 1 year compared to those aged 40+ years old with symptom duration ≥ 1 year. Additionally, patients ≥40 years old experienced a significantly longer symptom duration before surgery and had worse outcomes for mHHS and NAHS at 2- and 5-year follow-up compared to the 18–30 year cohort.

Purpose: To investigate the relationship between postoperative activity levels, measured via a smartphone application, and the incidence of iliopsoas tendinitis (IPT) following hip arthroscopy for femoroacetabular impingement syndrome (FAIS). We hypothesized that lower postoperative activity levels across the monitored 12-week period would be associated with increased IPT risk. Methods: This prospective cohort study enrolled patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) from June 2022 to February 2023. Average weekly step counts across the 12-week postoperative monitoring period were tracked via a smartphone application. Patients were stratified into IPT and non-IPT groups, and preoperative and postoperative outcomes, including the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and Visual Analog Scale (VAS), were compared. Activity levels were categorized into low, moderate, and high groups based on percentile distributions. Results: A total of 54 patients (mean age 37.8 ± 11.6 years, 59.3% female) were included, with 16 (29.6%) developing IPT at an average of 2.5 ± 1.2 months postoperatively. IPT patients had lower preoperative mHHS (62.2 vs. 74.9, p = 0.026) and NAHS (53.9 vs. 66.9, p = 0.023), and greater pain (VAS 6.3 vs. 5.0, p = 0.054). Mean weekly step counts were lower in the IPT group in every postoperative week, reaching statistical significance at Weeks 3 and 12 (p = 0.042 and p = 0.012). In penalized regression adjusted for preoperative mHHS and age, each additional 1000 steps per day during Weeks 1–3 was associated with lower odds of IPT (OR 0.63, 95% CI 0.32 to 0.98, p = 0.037); associations for later periods were in the same direction but did not reach statistical significance (Weeks 10–12: OR 0.89, 95% CI 0.66 to 1.10, p = 0.29). Functional improvements at 3 months did not differ between groups. Conclusions: Lower postoperative step counts were associated with a higher risk of IPT development, with the most robust association observed in the immediate postoperative period (Weeks 1–3), highlighting the potential importance of monitored, progressive rehabilitation following hip arthroscopy. These findings are exploratory and hypothesis-generating and require prospective interventional validation.