Ahmad, Rana

Abstract Introduction Periacetabular osteotomy (PAO) is performed in the setting of hip dysplasia to increase acetabular coverage of the femoral head and improve joint biomechanics and longevity. PAO fixation is generally achieved with two or three 4.5 mm screws, as compared to the generally more substantial plate and screw constructs used in the setting of acetabular fractures or pelvic ring injuries. The purpose of this study was to evaluate postoperative changes in hip joint center medialization and lateral acetabular coverage following PAO, understanding that these radiographic measures are generally used to guide intra-operative assessment of correction. Methods A retrospective chart review of 100 consecutive PAOs during 2021-2023 at a single academic institution by four surgeons was performed. Perioperative radiographs and fluoroscopy images were evaluated to measure lateral center edge angle (LCEA), Tönnis angle, and medialization of the hip joint center. The hip joint center was measured at one-third of the diameter of the femoral head from inferior to superior, to the ilioischial line, as previously validated by Fowler and colleagues. Results One hundred PAOs in 87 patients (87% female, mean age: 23.0 years) were included. Average preoperative radiographic parameters were 19.9° for LCEA, 12.5° for Tönnis angle, and 12.6 mm for distance from the femoral head to ilioischial line. Ninety-four cases (94%) used three screws, and 6 cases (6%) used two screws for unstable fragment fixation. On immediate postoperative films, average correction was to 28.3° for LCEA, 4.9° for Tönnis angle, and 1.9 mm of pre- to postoperative femoral head medialization (p≤0.001). Patients were radiographically followed for an average of 13.3 months, with an average time to radiographic union of 7.1 months. During the course of follow-up, LCEA increased to 29.3°, Tönnis angle remained to 5.0° (p=0.47), and medialization increased to 2.7 mm (p≤0.02), suggesting further significant but clinically modest increases in lateral coverage and femoral head medialization. Conclusion While the majority of lateral acetabular coverage and femoral head medialization occurs intra-operatively at the time of PAO, patients undergo modest but statistically significant postoperative increases in lateral coverage and medialization prior to radiographic union.

Abstract Introduction Understanding factors that impact outcomes of total hip arthroplasty (THA) can aid clinical decision-making and patient counselling. The purpose of this study was to investigate functional outcomes, complications, and reoperation rates among patients undergoing primary THA after hip arthroscopy (HA-THA) compared to a matched cohort of primary THA patients without prior arthroscopy (THA-only). Methods A retrospective review was performed to identify all patients who underwent primary THA after prior hip arthroscopy from 2009-2022 at a single institution. Patients with a history of revision arthroscopy were excluded. Cases were propensity-matched with primary THA controls in a 1:4 ratio by age at time of THA, sex, body mass index, surgical approach, and year of surgery. At minimum 2-year follow-up, patient-reported outcomes (PROs) including Forgotten Joint Score (FJS), Modified Harris Hip Score (mHHS), Hip Disability and Osteoarthritis Outcome Score Pain (HOOS pain), and Visual Analog Pain Scale (VAS) were analyzed. Results Sixty-three hips in 60 patients (age: 47.3±9.4 years, BMI: 29.8±6.2 kg/m2) were matched to 252 THA-only hips, with patients converting to THA at a mean 3.1 years (range 0.3-10.3) following hip arthroscopy. While both HA-THA and THA patients demonstrated significant (p<0.001) postoperative improvements in PROs, HA-THA patients reported significantly lower postoperative FJS, mHHS, HOOS pain, and VAS pain scores (p<0.001) as compared to THA-only controls. At mean 6.6±3.2 years follow-up, HA-THA patients with preoperative Tönnis grades 2-3 reported significantly increased FJS, mHHS, and HOOS pain compared to those with preoperative Tönnis grades of 0-1 (p≤0.03). Additionally, HA-THA patients with preoperative Tönnis grades 0-1 exhibited worse PROs (p<0.001) as compared to THA-only controls. While there were no differences in complication rates between HA-THA patients and THA-only controls (8% vs. 5%, p=0.49), all-cause reoperation was greater amongst HA-THA patients compared to THA-only (10% vs. 2%, p=0.01). Conclusion While improved compared to preoperatively, patients undergoing THA after prior hip arthroscopy demonstrated inferior outcomes at mid-term follow up as compared to a demographically age-matched cohort without prior arthroscopy. When considering conversion to THA following arthroscopy, clinicians should consider counseling patients regarding improved outcomes in the setting of advanced radiographic osteoarthritis, and potentially increased all-cause reoperation.