Citations

Abstract Background Iliopsoas impingement (IPI) is a known cause of persistent anterior hip pain following total hip arthroplasty (THA). Management of IPI has often relied on an 8mm anterior acetabular overhang threshold to guide operative treatment, favoring acetabular revision for greater prominence and iliopsoas tenotomy for lesser prominence. These thresholds were initially established based on the outcomes of open tenotomy, and now with improved understanding of IPI and the advent of arthroscopic iliopsoas fractional lengthening (IPFL), a review of the 8 mm threshold is warranted. Materials A retrospective review was performed to identify patients who underwent arthroscopic IPFL following primary THA between 2017 and 2024, with a minimum of one year of follow-up. Acetabular overhang was measured for all patients using cross-table lateral radiograph and patients were stratified into <8mm and ≥8mm cohorts. Patient-reported outcome measures (PROMs), reoperations, revisions, and complications were collected and analyzed based on both the classic 8 mm threshold using continuous statistical methods. Results Eighty-six hips undergoing IPFL in 83 patients (30 male, 53 females, age: 63.0 ± 11.2) were evaluated. Sixty-seven hips had <8mm of overhang and nineteen had ≥8 mm. Mean follow-up was 2.5 ± 1.6 years (range: 1- 7.5 years). When comparing patients with <8mm and ≥8mm acetabular overhang, there were no significant differences (p ≥0.06) observed between pre- and postoperative VAS pain scores, modified Harris Hip Score, SANE score, Tegner activity level, subjective groin pain improvement, subjective hip flexion strength, and overall satisfaction. Reoperation (2.9 vs. 10.5%, p = 0.210) and acetabular revision rates (1.5 vs. 5%, p = 0.387) were not significantly different between overhang groups. Conclusions Arthroscopic IPFL provides satisfactory outcomes for patients with IPI, independent of degree of acetabular overhang. IPFL should be considered for first-line surgical management of IPI refractory to conservative management, even in the setting of substantial acetabular overhang, given positive outcomes and low rates of subsequent acetabular revision.

Abstract Purpose To evaluate patient-reported outcome measures at a minimum of 5-years of follow-up and return to sport (RTS) in dancers with femoroacetabular impingement (FAI) after primary hip arthroscopy with labral repair. Methods Dancers diagnosed with FAI and labral tears undergoing primary hip arthroscopy with labral repair from 2010 to 2020 were included. Modified Harris Hip Score (mHHS), Hip Outcome Score Activities of Daily Living (HOS-ADL), HOS Sports-Specific Subscale (HOS-SSS), Tegner Activity Score, Visual Analogue Scale (VAS) for pain, and surgery satisfaction were collected. Results Twenty-six dancers (25 female and 1 male; mean age, 22 ± 7; mean body mass index (BMI), 23.9 ± 4.6) were followed for a mean of 8.2 years. At final follow-up, the mean and 95% CI for VAS pain with rest was 1.8 (0.9-2.6), VAS pain with use was 3.3 (2.2-4.4), Tegner Activity Scale was 5.0 (4.2-5.9), mHHS Total was 82.4 (75.9-88.9), HOS-ADL was 90.0 (85.2-94.7), and HOS-SSS was 78.4 (69.1-87.6). All outcome scores significantly improved postoperatively (p ≤ 0.027), and MCID achievement was 91.0% for mHHS total, 85.7% for HOS-ADL, and 91.0% for HOS-SSS. One patient (4%) underwent revision hip arthroscopy and labral repair for a re-tear of the labrum. Nineteen (76%) returned to sport, of which 17 (89%) returned to the same or higher level. Seven patients (37%) had subsequently stopped for reasons unrelated to hip symptoms, while four (21%) stopped for hip related reasons. Conclusion Treatment of FAI with hip arthroscopy in dancers leads to improvement in outcomes with a high rate of satisfaction at mean follow-up of 8.2 years. Seventy-six percent of dancers ultimately returned to dance, of which 89% returned to the same level, and majority subsequently discontinuing for non-hip related reasons. These results support a high rate of RTS in dancers after hip arthroscopy with labral repair for the treatment of FAI with maintained level of dance competition and improvement in PROMs at mid-term follow-up.

Abstract Background The use of collared femoral stems are becoming increasingly popular in total hip arthroplasty (THA) due to improved axial stability and decreased periprosthetic femoral fractures. However, the effect of the initial collar–calcar relationship on femoral remodeling is poorly understood. Methods A retrospective review of 700 primary THAs using triple-tapered collared stems with a minimum 2-year radiographic follow-up was performed. Radiographic imaging was analyzed to determine the collar–calcar relationship, measured as the distance between the medial edge of the collar and the medial calcar on antero-posterior radiographs at time zero and ≥2-year follow-up. The collar-calcar relationship was classified into three distinct groups: overhang, flush, and underhang. Overhang was defined as the collar extending medial to the calcar, flush as the collar sitting directly on top of the calcar, and underhang as the medial portion of the collar lateral to the medial calcar. The change in the collar–calcar relationship over time was analyzed as calcar remodeling. Furthermore, a linear regression model was used to determine how baseline position predicted 2-year collar position, with the goal to identify an ideal relationship at implantation to achieve a flush collar at two-year follow-up. Results At implantation, 370 (52%) of stems demonstrated a underhang, 56 (8%) were flush, and 274 (39%) showed overhang. For the entire cohort, the mean collar-calcar relationship changed from −0.68 ± 2.5 mm at implantation to 1.9 ± 1.9 mm at final follow-up (p < 0.001). Collared stems with underhang demonstrated the greatest remodeling (3.5 ± 1.9 mm), followed by flush (2.1 ± 1.4 mm) and overhang (1.5 ± 1.4 mm) (p < 0.001). Pairwise comparison demonstrated statistically significant difference between all three groups (p <0.001). Each 1 mm increase in baseline overhang was associated with a decrease of 0.5 mm change in calcar remodeling (95% CI −0.55 to −0.46; p < 0.001). To achieve a flush collar at two years a baseline underhang of −4.52 mm (95% CI −4.97 to −4.15) was required. Reoperation rates were low and did not differ between all three groups. Conclusions The collar–calcar relationship evolves predictably over time, with baseline position impacting final collar prominence. Immediate implant position does not reflect the final construct, however it does plays a role in calcar remodeling.

Abstract Background The THA-10 Score is a risk stratification tool to help predict 10-year conversion to total hip arthroplasty (THA) following hip arthroscopy (HA) for femoroacetabular impingement (FAI). It is intuitive that the score demonstrated predictive accuracy on the original cohort utilized to create the metric. However, external validation has not yet been conducted. The purpose of the present study was to externally validate the THA-10 Score using a large single-institution cohort with long-term follow-up. Methods A retrospective review was conducted of patients who underwent primary HA with labral repair and capsular repair between 2011 and 2015. Inclusion criteria required a minimum of 10-year follow-up. Exclusion criteria included revision surgery, Tonnis grade ≥2, lateral center-edge angle <18°, or periacetabular osteotomy. The THA-10 Score was calculated by assigning points for body mass index (BMI) ≥25 kg/m2 (1 point), Tonnis grade 1 (1 point), age ≥47 years (2 points), and high-grade (Outerbridge grade 3 or 4) acetabular and femoral head chondral defects (3 points each). Discrimination was assessed using receiver operating characteristic (ROC) analysis and calibration was evaluated using the Brier score. Results The final cohort consisted of 215 patients (74.0% female, mean age 33.6 ± 13.0 years, mean BMI 26.9 ± 6.4 kg/m2). At a mean follow-up of 11.1 years (range 10.0-13.9 years), 23 patients (10.7%) underwent conversion to THA. The THA-10 Score demonstrated sufficient discrimination with an area under the curve (AUC) of 0.763. Calibration analysis demonstrated a Brier score of 0.078 with a p-value of 0.115, which is consistent with appropriate model calibration. Patients with THA-10 Scores ≥4 had 10.4-times greater odds of conversion to THA compared to those with scores <4 (p<0.001). Conclusions The THA-10 Score demonstrated sufficient discrimination and appropriate calibration for predicting 10-year THA conversion after HA for FAI. These findings support the use of the THA-10 Score as a counseling and risk-stratification tool in patients undergoing HA.

Abstract ICLA14 - The Extra-Articular Masterclass: Endoscopic Repairs, Ischiofemoral Fixes, and Complex Alignment, Auditorium A (BMCC Level 1), October 9, 2026, 14:00 - 16:00 Introduction Iliopsoas impingement (IPI) is an increasingly recognized cause of persistent groin pain and dysfunction after total hip arthroplasty (THA). The incidence of clinically important IPI requiring surgical treatment remains incompletely defined. For IPI refractory to conservative management surgical treatment options include acetabular revision, open tenotomy, or arthroscopic iliopsoas fractional lengthening and often is done years following initial symptom onset. As such, the true incidence of persistent IPI and associated risk factors resulting in subsequent surgical management are incompletely characterized. We sought to determine the prevalence of, and risk factors for, surgical IPI treatment after primary THA at a single high-volume institution. Materials and Methods We performed a retrospective review of all primary THAs done from 2010 to 2025 and identified subsequent surgical IPI procedures performed within our health system during the same period. Patient demographics, surgical approach, and implant specific criteria were evaluated. Univariable and multivariable Cox proportional hazards models were used to determine risk factors associated with surgical IPI treatment. Results Seventy-one Iliopsoas Impingement Management (IPIM) procedures were performed after 18,497 primary THAs (prevalence, 0.4%). The prevalence by surgical approach was 0.4% for direct anterior, 0.5% for lateral, and 0.3% for posterior approaches. In multivariable analysis, factors associated with surgical IPI treatment included female sex (hazard ratio [HR], 2.35; p=0.001), direct anterior approach compared with posterior approach (HR, 2.06; p=0.024), and younger age (HR, 0.97; p<0.001). Body mass index, acetabular component size, anteversion, and inclination were not associated with IPIM (p≥0.074 ). Conclusion Surgical treatment of IPI after primary THA was uncommon (0.4%) but not rare. Women, younger patients, and those treated with a direct anterior approach had a greater risk of subsequent surgical IPI treatment. These findings may assist in patient counseling and in setting expectations regarding the likelihood of iliopsoas-related reoperation after contemporary primary THA.

Abstract ICLA12 - The Chondral Masterclass: Advanced Scaffolds, Orthobiologic Realities, and Young THA, Auditorium B (BMCC Level 1), October 9, 2026, 10:30 - 12:30 Introduction Total hip arthroplasty (THA) in patients with open triradiate cartilage is rare, but results in good midterm survivorship and clinical outcomes in failed hip preservation adolescents. Currently, there is limited literature evaluating the potential impact of THA on further acetabular and pelvic growth, and common radiographic parameters in the setting of an open triradiate cartilage. Our primary aim was to assess the acetabular component position at midterm follow up after THA in skeletally immature patients with open triradiate cartilage. Our secondary aim was to report midterm radiographic and clinical outcomes, including leg length and offset, after THA in patients with open triradiate cartilage. Methods Our institutional Total Joint Registry was queried to identify 24 THAs (23 patients) with an open triradiate cartilage at the time of index operation between 2000 and 2024. Skeletal maturity was assessed utilizing the modified Oxford bone age, with only triradiate scores of 1 and 2 included. Demographic, implant, and radiographic data were collected. Acetabular component inclination and version, leg lengths, and femoral and acetabular offset were measured on anteroposterior and cross table lateral radiographs immediately postoperatively and at final follow-up. The final cohort for radiographic analysis included 20 THAs (17 patients) with a mean age of 14 years and 55% male. Patients had a mean BMI of 26 kg/m2 and mean modified Oxford bone age score of 21.6. Mean follow up with radiographs was 5.7 years (median=4.9, SD=3.8). Results The indications for THA were avascular necrosis (70%), secondary arthritis (25%), and neoplasia (5%). Acetabular component inclination (Mean change in inclination 0.91°, 95% CI inclination [-4.4, 2.7], p=0.61) and acetabular component version (Mean change in anteversion -2.8°, 95% CI [-3.3, 8.9], p=0.35) did not change from immediately postoperatively to final follow-up. Similarly, there was no change in leg length (Mean change in leg length -0.5mm, 95% CI [-2.0, 5.0], p=0.38) at final follow-up. There was one revision for acetabular component loosening and no separate reoperations. The survivorships free of revision and reoperation were 95%, respectively. Conclusion Acetabular component version and inclination remain unchanged following THA performed in skeletally immature patients with open triradiate cartilage. Survivorship free of revision was excellent at 95% in mid-term follow up of 6 years. These findings suggest that THA is safe and durable in skeletally immature patients with minimal risk of implant positional change or significant leg length discrepancy during final skeletal maturation.

Abstract ICLB09 - The Revision Playbook: Advanced Execution and Technical Rescues in Failed Preservation, Session Room 6 (BMCC Level 3), October 9, 2026, 10:30 - 12:30 Purpose To evaluate outcomes of revision hip arthroscopy by prior surgical procedure, revision indication, and to compare patient-reported outcomes and rates of re-revision or conversion to arthroplasty across revision indications and procedures performed. Methods A retrospective review was conducted of patients undergoing first-time revision hip arthroscopy between 2011 and 2020 at a single institution. Operative details were collected at both the index and revision surgeries, including whether cam or pincer resection was performed. Patient reported outcome measures (PROMs) were collected for patients without revision failure. Rates of re-revision arthroscopy or conversion to total hip arthroplasty (THA) were measured. Statistical analysis included appropriate tests for group comparisons and Cox proportional hazards models to identify predictors of failure. Results A total of 68 hips were included (mean age 33 ± 11.7 years, 81.2% female). The most common indications for revision were recurrent labral tear (89.9%) and residual femoroacetabular impingement (FAI) (63.8%). At index arthroscopy, 69.1% underwent cam and/or pincer resection. At the time of revision, 64.7% underwent cam and/or pincer resection, with 32.4% undergoing repeat osseous work. Labral repair (18.8%) and labral debridement (14.5%) were the most frequent soft-tissue procedures performed at revision. Patients with bony correction at only index and only revision hip arthroscopy reported comparable PROMs. Overall, 1 patient underwent repeat revision arthroscopy and 13 patients (18.8%) converted to THA at a mean of 1.4 years following revision. Labral debridement (HR 9.79, 95% CI 3.25–29.5, p < 0.001) and labral repair (HR 4.56, 95% CI 1.57–13.2, p = 0.01) were associated with higher failure risk. Conclusion Revision hip arthroscopy offers symptomatic improvement for most patients, however, failure may be more common among those with incomplete osseous correction or labral debridement at revision. Attention to comprehensive bony and soft tissue management during primary and revision procedures may reduce the risk of re-revision and conversion to arthroplasty.

Abstract Purpose The purpose of this study was to evaluate changes in hip capsular height on magnetic resonance imaging (MRI) before and after hip arthroscopy and to report associated patient-reported outcomes. Methods A retrospective case series was performed of patients who underwent hip arthroscopy with both preoperative and postoperative MRI arthrogram available. Demographics including age, sex, body mass index (BMI), and laterality were collected. Capsular height was measured preoperatively and postoperatively on MRI, to determine whether intra-operative capsular elevation resulted in durably altered capsulolabral recess morphology on subsequent imaging. The primary outcome analyzed was postoperative capsular height and change from baseline. Patient-reported outcomes collected included Tegner activity score, Visual Analog Scale for pain at rest and with activity, modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sports, subjective surgery outcome, and surgery satisfaction (0-10). Results Fifty hips were included with a mean age of 30.9 ± 10.9 years and mean BMI of 29.1 ± 6.3 kg/m2. There were 37 females (74.0%) with 28 right hips (56.0%). Mean time from preoperative MRI to surgery was 0.6 ± 0.7 years (range, 0.0 – 3.6 years), and from surgery to postoperative MRI was 2.5 ± 1.6 years (range, 0.2 – 6.6 years). Preoperative capsular height was 2.2 ± 3.2 mm and increased to 7.9 ± 5.4 mm postoperatively (p<0.01) (Δ 5.7 ± 6.3 mm). At a mean follow-up of 4.7 ± 1.4 years, Tegner scores improved from 3.2 ± 2.1 preoperatively to 4.6 ± 2.4 postoperatively. Mean VAS scores were 2.4 ± 2.7 at rest and 4.2 ± 2.7 with use. Mean mHHS was 72.0 ± 17.6, HOS-ADL was 81.4 ± 16.5, and HOS-Sports was 71.1 ± 28.2. Mean satisfaction (0-10) was 7.1 ± 2.5, with 83.3% of patients reporting they felt “much better” or “slightly better” after surgery. Additionally, neither postoperative capsular height nor magnitude of postoperative change in capsular height were correlated patient-report outcome scores. Conclusions Hip arthroscopy is associated with a measurable increase in capsular height on postoperative MRI, suggesting capsular elevation following intervention. These findings provide early quantitative imaging evidence demonstrating changes in capsular morphology postoperatively and highlight the need for further studies correlating capsular elevation with long-term clinical outcomes.

Abstract Background Femoral stem collars are intended to improve axial stability and load transfer following total hip arthroplasty (THA). However, substantial variability exists in collar geometry across implant systems, and how collar size and collar–calcar interaction influences femoral remodeling and the risk of mechanical complications remains incompletely understood. The purpose of this study was to determine radiographic calcar remodeling over time and to compare reoperation rates between femoral stems with constant-length collars (CLC) and size-specific collars (SSC), with the goal of better defining an optimal collar geometry. Methods A retrospective cohort study was performed using an institutional total joint registry to identify patients undergoing primary THA with either a CLC stem or an SSC stem. Radiographic measurements of collar overhang and collar-calcar gap were obtained at immediate postoperative, 3-month, and ≥2-year follow-up. Logistic regression models evaluated predictors of collar-calcar gap formation and closure. Receiver operating characteristic analysis identified a threshold for predictive gap resolution. A numerical optimization model was used to estimate the medial-to-lateral collar length that minimized absolute collar-calcar mismatch over time. Results Collar-calcar gaps were present in 12% of cases postoperatively, with resolution in 87% at final follow-up. Initial gap magnitude was the primary predictor of gap closure (OR 0.30 per mm, p < 0.001), with ROC analysis identifying an optimal cutoff of 1.54 mm for gap resolution. Progressive medial collar overhang increased over time. Optimization modeling demonstrated that the collar length minimizing absolute collar-calcar mismatch decreased from 7.5 mm at implantation to approximately 5.3 mm at final follow-up. Reoperation rates did not differ between implant designs, however occurred disproportionately in smaller CLC femoral stem sizes. Conclusion Proximal femoral remodeling following THA results in predictable thinning of the femoral calcar and progressive medial collar overhang over time. These findings suggest that collar geometry, particularly in smaller femora, should be considered relative to patient anatomy rather than implant design philosophy alone.

Abstract Background The level of femoral neck resection in total hip arthroplasty (THA) affects implant position, restoration of limb length, and the degree of cortical support available for collared cementless stems. With the increasing use of computed tomography (CT)-based planning and collared femoral stems, a clearer understanding of femoral neck and calcar morphology at the osteotomy plane is valuable. We sought to quantify cortical thickness at the planned neck resection level, characterize variability across adjacent axial levels, and determine an optimal collar length to minimize overhang and underhang. Methods We reviewed preoperative CT scans from 100 consecutive primary THAs performed by a single surgeon. Using multiplanar reconstruction, calcar cortical thickness was measured on axial images at the planned osteotomy level (0mm) and at standardized levels 5.30 mm proximal and 5.30 mm distal to that plane. At each level, thickness was recorded at 5 locations (anterior, posterior, medial, anteromedial, and posteromedial). An idealized medial-to-lateral collar length was then calculated to minimize absolute collar overhang and underhang across the cohort. Results Cortical thickness increased from proximal to distal levels, most prominently in the medial (p<0.001) and posteromedial (p<0.001) regions. Anteromedial thickness increased from the proximal level to the osteotomy plane (p=0.004) but did not increase further distally (p=0.641). Sex-based differences were limited; the only significant difference was greater anteromedial thickness in women at the proximal level (3.9 versus 3.3 mm; p=0.048). The collar length that minimized absolute overhang/underhang was 5.30 mm. Conclusion At and around the planned femoral neck osteotomy plane, medial and posteromedial cortices were thickest and increased in thickness distally, whereas anteromedial thickness plateaued, and a collar length of 5.3mm minimized overhang/underhang. These data provide an anatomic reference to inform cementless femoral stem collar geometry and optimize collar-cortical contact in primary cementless THA.