Periacetabular osteotomy after failed hip arthroscopy demonstrates improved outcomes in a heterogenous patient population: a systematic review.

PURPOSE: To evaluate the literature on patients undergoing periacetabular osteotomy after failed hip arthroscopy (PAO-FHA) for (1) patient demographics and hip morphology, (2) changes in preoperative to postoperative patient-reported outcomes (PROs), and (3) PROs in comparison to primary periacetabular osteotomy (PAO) patients. METHODS: A systematic literature search of Pubmed, CINAHL/Medline, and cochrane databases was performed in accordance with PRISMA guidelines. The search phrase was "(periacetabular osteotomy or PAO or rotational osteotomy) and (hip arthroscopy or arthroscopic)". The titles, abstracts, and full texts were screened for studies on PAO-FHA. Study quality was assessed, and relevant data were collected. A meta-analysis was not performed due to study heterogeneity. RESULTS: The search identified 7 studies, including 151 hips (148 patients, 93.9% female) undergoing PAO-FHA, out of an initial 593 studies, with three Level IV and four Level III studies. Mean time from hip arthroscopy to PAO ranged from 17.0 to 29.6 months. Heterogenous hip morphologies and radiologic findings prior to PAO were observed, though patients most frequently demonstrated moderate-to-severe dysplasia (mean or median lateral center edge angle < 20°) and minimal osteoarthritis (Tönnis grade 0 or 1). In all 5 studies that reported concomitant procedures with PAO, femoral and/or acetabular osteoplasty was performed via arthroscopy or arthrotomy. Following PAO-FHA, radiographic acetabular coverage and PROs improved in all 6 studies that reported postoperative outcomes. All four comparative studies of primary PAO vs. PAO-FHA included patients with mean or median LCEAs < 20°, reporting mixed outcomes for the optimal treatment approach. CONCLUSION: PAO-FHA is reported in a heterogenous patient population that frequently includes hips with moderate-to-severe dysplasia and minimal osteoarthritis. Regardless of hip morphology or concomitant procedures, all studies that reported postoperative outcomes demonstrated improved PROs following PAO-FHA. LEVEL OF EVIDENCE: Level IV.

Hip kinematics in healthy adults during gait and squatting: Sex differences and asymmetry revealed through dynamic biplane radiography.

There is a lack of data unaffected by soft tissue artifact describing bilateral symmetry and sex differences in hip kinematics in asymptomatic individuals during activities of daily living. This study aimed to identify sex-based differences and to quantify bilateral symmetry in continuous hip kinematics during walking and bodyweight squatting using biplane radiography. Twenty-four asymptomatic young adults (13 women, 11 men; age: 21.9 ± 2.2 years) performed treadmill walking and squatting while synchronized biplane radiographs of the hip were collected at 50 frames/s. Pelvis and proximal femur bone tissue were segmented from CT images and reconstructed into subject-specific 3D bone models. Femoroacetabular kinematics were determined using a validated volumetric model-based tracking technique that matched digitally reconstructed radiographs generated from the CT-based bone models to the biplane radiographs. Symmetry was calculated as the average absolute side-to-side difference (SSD) in kinematic waveforms for each participant. Sex-based and phase-based (eccentric vs. concentric squatting) kinematic variations were assessed using linear mixed model analysis. Women were 0.2 mm more anteriorly translated and 0.1 mm more inferiorly translated than men across the gait cycle (both p < 0.04), but no sex-based or phase-based kinematic differences during squatting were identified. The maximum SSD across all movements was up to 18.6° (internal-external rotation) and 1.0 mm (superior-inferior translation), respectively. Asymmetry in internal rotation, superior translation, and medial translation was greater during squatting than during walking (all p < 0.002). This study provides a reference dataset of healthy young adults for evaluating hip kinematics and symmetry in symptomatic cohorts or in individuals undergoing surgery or rehabilitation.

A systematic approach to CT evaluation of non-arthritic hip pain.

Bone morphology has been increasingly recognized as a significant variable in the evaluation of non-arthritic hip pain in young adults. Increased availability and use of multidetector CT in this patient population has contributed to better characterization of the osseous structures compared to traditional radiographs. Femoral and acetabular version, sites of impingement, acetabular coverage, femoral head-neck morphology, and other structural abnormalities are increasingly identified with the use of CT scan. In this review, a standard CT imaging technique and protocol is discussed, along with a systematic approach for evaluating pelvic CT imaging in patients with non-arthritic hip pain.