Lateral Center-edge Angle Research Articles

Assessing hip joint-related structure and patient-reported outcomes in people with Marfan syndrome.

People with Marfan syndrome (MFS) have clinical symptoms of hip pain, but to date, there is limited knowledge about hip-related structural abnormalities in these patients. Therefore, the purpose of this cross-sectional study was to assess hip-related structural abnormalities and patient-reported outcomes (PRO) in a cohort of patients with MFS compared to healthy controls. Nineteen individuals with MFS(17 females, 39.8±11.5 years) and 19 age, sex, and body mass index-matched healthy, asymptomatic individuals (17 females, 36.2±12.5 years)underwent radiographic imaging and unilateral hip MRI. The Scoring Osteoarthritis with MRI (SHOMRI) technique was used to assess hip-related morphological abnormalities between the MFS and control groups. All participants completed the Hip disability and Osteoarthritis Outcome Score (HOOS) to assess hip-related symptoms, pain, and function during activities of daily living (ADL) and quality of life (QOL). The MFS group exhibited higher lateral center edge angles (p < .001). Despite similar severity of femoral cartilage damage (p = 1.0), the MFS group exhibited a higher severity (p = 0.046)of acetabular cartilage degeneration (1.21±1.08) compared to the controls(0.53±1.02). There were no between-group differences in severity of labral pathology, subchondral cysts, or edema. Individuals with MFS also self-reported significantly lower HOOS symptoms (p = 0.003), pain (p = 0.014), ADL (p = 0.028), and QOL (p = 0.014) sub-scores, indicating worse hip-related PRO in MFS. Our study results suggest that individuals with MFS exhibit early signs of acetabular cartilage degeneration and poor hip-related clinical outcomes compared to healthy individuals. Future work should investigate the underlying biomechanical mechanisms associated with hip joint degeneration in the MFS population.

Application of 3D-printed individualized porous tantalum buttress in shelf acetabuloplasty for developmental dysplasia of the hip

Shelf acetabuloplasty is a viable treatment for developmental dysplasia of the hip (DDH), yet autologous bone grafts have faced challenges such as morphological mismatch, imprecise placement, and long-term graft resorption. The rapid advancement of three-dimensional (3D) printing technology in orthopedics has enabled the acquisition of digital image correlation method (DICM) data from patient pelvic to bilateral femoral proximal regions through computed tomography (CT) scans. This data is then utilized by software to create 3D models and design individualized metal implants. Using tantalum-based TA1 type I spherical powder as the raw material, a porous tantalum buttress with a pore size of 600 microns and a porosity of 75% was fabricated employing the selective electron beam melting (SEBM) technology. Our Center has applied this 3D-printed individualized porous tantalum buttress in shelf acetabuloplasty for 21 DDH patients (25 hips), including 6 males and 15 females, with a mean age of (21.38&amp;plusmn;7.39) years. The follow-up period ranged from 12 to 47 months, averaging (22.64&amp;plusmn;10.86) months. At the final follow-up, patient-reported outcomes (PROs) were used to assess patient&amp;rsquo;s subjective feelings. Significant improvements were observed in the Non-Arthritic Hip Score (NAHS), modified Harris Hip Score (mHHS), Hip Outcome Score-Sports Subscale (HOS-SSS), International Hip Outcome Tool-12 (iHOT-12), and Visual Analog Scale (VAS) compared with preoperative levels (P&lt;0.01). Radiographic assessments showed that postoperative lateral center edge (LCE) angle, Tonnis angle, acetabular angle (Sharp&amp;rsquo;s angle), and femoral head coverage all trended towards normal, with statistically significant differences (P&lt;0.01). There was no implant displacement or bone resorption in any case, and no progression in Tonnis grading for hip osteoarthritis (OA) was noted postoperatively, with an 84% patient satisfaction rate. The early follow-up results of 3D-printed individualized porous tantalum buttress in shelf acetabuloplasty are satisfactory, indicating a reliable application prospect for the treatment of DDH patients.

IDENTIFYING RISK FACTORS FOR DISEASE PROGRESSION IN DEVELOPMENTAL DYSPLASIA OF THE HIP USING A CONTRALATERAL HIP MODEL

Developmental dysplasia of the hip can cause pain and premature osteoarthritis. However, the risk factors and timing for disease progression in young adults are not fully defined. This study identified the incidence and risk factors for contralateral hip pain and surgery after periacetabular osteotomy (PAO) on an index dysplastic hip.Patients followed for 2+ years after unilateral PAO were grouped by eventual contralateral pain or no-pain, based on modified Harris Hip Score, and surgery or no-surgery. Univariate analysis tested group differences in demographics, radiographic measures, and range-of-motion. Kaplan-Meier survival analysis assessed pain development and contralateral hip surgery over time. Multivariate regression identified pain and surgery risk factors. Pain and surgery predictors were further analyzed in Dysplastic, Borderline, and Non-dysplastic subcategories, and in five-degree increments of lateral center edge angle (LCEA) and acetabular inclination (AI).184 patients were followed for 4.6±1.6 years, during which 51% (93/184) reported hip pain and 33% (60/184) underwent contralateral surgery. Kaplan-Meier analysis predicted 5-year survivorship of 49% for pain development and 66% for contralateral surgery. Painful hips exhibited more severe dysplasia than no-pain hips (LCEA 16.5º vs 20.3º, p&lt;0.001; AI 13.2º vs 10.0º p&lt;0.001). AI was the sole predictor of pain, with every 1° AI increase raising the risk by 11%. Surgical hips also had more severe dysplasia (LCEA 14.9º vs 20.0º, p&lt;0.001; AI 14.7º vs 10.2º p&lt;0.001) and were younger (21.6 vs 24.1 years, p=0.022). AI and a maximum alpha angle ≥55° predicted contralateral surgery.5 years after index hip PAO, 51% of contralateral hips experience pain and 34% percent are expected to need surgery. More severe dysplasia, based on LCEA and AI, increases the risk of contralateral hip pain and surgery, with AI being a predictor of both outcomes. Knowing these risks can inform patient counseling and treatment planning.

DYSPLASTIC HIPS THAT ARE TOO LATE FOR PERIACETABULAR OSTEOTOMY ARE NOT TOO EARLY FOR TOTAL HIP ARTHROPLASTY

Total hip arthroplasty (THA) is often performed in symptomatic patients with developmental dysplasia of the hip (DDH) who do not qualify for periacetabular osteotomy (PAO). The impact of osteoarthritis (OA) severity on postoperative outcomes in DDH patients who undergo THA is not well described. We hypothesized that DDH patients who undergo THA with mild OA have slower initial recovery postoperatively, but similar one-year patient reported outcome measures (PROMs) when compared to DDH patients with severe OA.We performed a retrospective review at a single academic institution over a six-year period of patients with DDH who underwent primary THA and compared them to patients without DDH who underwent THA. Within the DDH cohort, we compared PROMs stratified by DDH severity and OA severity. Diagnosis of DDH was verified using radiographic lateral center edge angle (LCEA). Minimum one-year follow-up was required. PROMs were collected through one-year postoperatively. Logistic and linear regression models were used adjusting for age, sex, body mass index, and Charlson Comorbidity Index.263 patients with DDH were compared to 1,225 THA patients without DDH. No significant differences were found in postoperative PROMs or revision rates (p=0.49). When stratified by DDH severity, patients with LCEA&lt;10° had worse preoperative pain (p=0.01), mental health (p&lt;0.01) and physical function (p=0.03) scores but no significant difference in postoperative PROMs. Within the DDH group, when stratified by OA severity, patients with Grade 3 Tonnis score had worse preoperative pain (p=0.04) but no significant difference in postoperative PROMs. Recovery curves in DDH patients based upon severity of DDH and OA were not significantly different at 2-weeks, 6-weeks and 1-year.DDH patients who have mild OA have similar recovery curves compared to those with severe OA. THA is reasonable in symptomatic DDH patients who have mild arthritis and do not qualify for PAO.

MIXED-REALITY GUIDANCE FOR PELVIC OSTEOTOMY AND ACETABULAR REALIGNMENT: PROOF OF CONCEPT

Mixed Reality has the potential to improve accuracy and reduce required dissection for the performance of peri-acetabular osteotomy. The current work assesses initial proof of concept of MR guidance for PAO.A PAO planning module, based on preoperative computed tomography (CT) imaging, allows for the planning of PAO cut planes and repositioning of the acetabular fragment. 3D files (holograms) of the cut planes and native and planned acetabulum positions are exported with the associated spatial information. The files are then displayed on mixed reality head mounted device (HoloLens2, Microsoft) following intraoperative registration using an FDA-cleared mixed reality application designed primary for hip arthroplasty (HipInsight). PAO was performed on both sides of a bone model (Pacific Research). The osteotomies and acetabular reposition were performed in accordance with the displayed holograms. Post-op CT imaging was performed for analysis. Cutting plane-accuracy was evaluated using a best-fit plane and 2D angles (°) between the planned and achieved supra (SA)- and retroacetabular (RA) osteotomy and retroacetabular and ischial osteotomies (IO) were measured.To evaluate the accuracy of acetabular reorientation, we digitized the acetabular rim and calculated the acetabular opening plane. Absolute errors of planned and achieved operative inclination and anteversion (°) of the acetabular fragment, as well as 3D lateral-center-edge (LCE) angles were calculated.The mean absolute difference between the planned and performed osteotomy angles was 3 ± 3°.The mean absolute error between planned and achieved operative anteversion and inclination was 1 ± 0° and 0 ± 0° respectively. Mean absolute error between planned and achieved 3D LCE angle was 0.5 ± 0.7°.Mixed-reality guidance for the performance of pelvic osteotomies and acetabular fragment reorientation was feasible and highly accurate. This solution may improve the current standard of care by enabling reliable and precise reproduction of the desired acetabular realignment.

Deep learning-based pseudo-CT synthesis from zero echo time MR sequences of the pelvis

ObjectivesTo generate pseudo-CT (pCT) images of the pelvis from zero echo time (ZTE) MR sequences and compare them to conventional CT.MethodsNinety-one patients were prospectively scanned with CT and MRI including ZTE sequences of the pelvis. Eleven ZTE image volumes were excluded due to implants and severe B1 field inhomogeneity. Out of the 80 data sets, 60 were used to train and update a deep learning (DL) model for pCT image synthesis from ZTE sequences while the remaining 20 cases were selected as an evaluation cohort. CT and pCT images were assessed qualitatively and quantitatively by two readers.ResultsMean pCT ratings of qualitative parameters were good to perfect (2–3 on a 4-point scale). Overall intermodality agreement between CT and pCT was good (ICC = 0.88 (95% CI: 0.85–0.90); p < 0.001) with excellent interreader agreements for pCT (ICC = 0.91 (95% CI: 0.88–0.93); p < 0.001). Most geometrical measurements did not show any significant difference between CT and pCT measurements (p > 0.05) with the exception of transverse pelvic diameter measurements and lateral center-edge angle measurements (p = 0.001 and p = 0.002, respectively). Image quality and tissue differentiation in CT and pCT were similar without significant differences between CT and pCT CNRs (all p > 0.05).ConclusionsUsing a DL-based algorithm, it is possible to synthesize pCT images of the pelvis from ZTE sequences. The pCT images showed high bone depiction quality and accurate geometrical measurements compared to conventional CT.Critical relevance statementpCT images generated from MR sequences allow for high accuracy in evaluating bone without the need for radiation exposure. Radiological applications are broad and include assessment of inflammatory and degenerative bone disease or preoperative planning studies.Key PointspCT, based on DL-reconstructed ZTE MR images, may be comparable with true CT images.Overall, the intermodality agreement between CT and pCT was good with excellent interreader agreements for pCT.Geometrical measurements and tissue differentiation were similar in CT and pCT images.Graphical

Borderline Developmental Dysplasia of the Hip With Osseous Impingement as Distinct From Femoroacetabular Impingement and Developmental Dysplasia of the Hip.

Borderline developmental dysplasia of the hip (BDDH) accompanied by cam deformity and subspinous impingement has been found to benefit from arthroscopic surgery. However, the research comparing BDDH combined with osseous impingement to femoroacetabular impingement (FAI) without borderline dysplasia remains limited. To compare the clinical symptoms, intraoperative findings, and outcomes of hip arthroscopy in patients with BDDH and osseous impingement versus cam-type FAI. It was hypothesized that BDDH with osseous impingement could be classified as a distinct entity between FAI and developmental dysplasia of the hip (DDH). Cohort study; Level of evidence, 3. Data were collected from patients 18 to 50 years old who underwent primary hip arthroscopy between September 2016 and October 2020. Patients were divided based on preoperative lateral center-edge angle (LCEA) into 2 groups: (1) BDDH group (LCEA 18°-25°; n = 67); and (2) cam-type FAI group without BDDH (FAI group; LCEA 25°-40° and alpha angle >55°; n = 145). Disparities in symptoms, preoperative examination, intraoperative findings and procedures, and patient-reported outcome (PRO) scores were compared. Follow-up was available for 61 (91.0%) patients in the BDDH group and 125 (86.2%) patients in the FAI group. The incidence of cam deformity in BDDH patients was 91.8%. The preoperative characteristics and intraoperative findings were similar between the groups; however, preoperative internal and external hip rotation, Tönnis angle, femoroepiphyseal acetabular roof index, labral size, capsule thickness, and percentage of ligamentum teres tear were significantly higher in the BDDH group than the FAI group, and the percentage of pain aggravating factor, cam deformity, and anterior inferior iliac spine types 2 and 3 were also significantly different between groups (P < .05 for all). The percentage of intraoperative minimal acetabuloplasty, subspinous decompression, labral repair, ligamentum teres debridement, and capsular closure was significantly higher in the BDDH group than the FAI group, while the percentage of femoroplasty was higher in the FAI group (P < .05). Pre- to postoperative improvement on PRO scores was seen in both groups. Given the differences in etiology and surgical procedures between the 2 conditions, it is suggested that BDDH with osseous impingement be classified as an entity distinct from FAI and DDH (and separate from BDDH without impingement) while excluding joint instability.

Reliability and agreement of manual and automated morphological radiographic hip measurements

ObjectiveTo determine the reliability and agreement of manual and automated morphological measurements, and agreement in morphological diagnoses. MethodsThirty pelvic radiographs were randomly selected from the World COACH consortium. Manual and automated measurements of acetabular depth-width ratio (ADR), modified acetabular index (mAI), alpha angle (AA), Wiberg center edge angle (WCEA), lateral center edge angle (LCEA), extrusion index (EI), neck-shaft angle (NSA), and triangular index ratio (TIR) were performed. Bland-Altman plots and intraclass correlation coefficients (ICCs) were used to test reliability. Agreement in diagnosing acetabular dysplasia, pincer and cam morphology by manual and automated measurements was assessed using percentage agreement. Visualizations of all measurements were scored by a radiologist. ResultsThe Bland-Altman plots showed no to small mean differences between automated and manual measurements for all measurements except for ADR. Intraobserver ICCs of manual measurements ranged from 0.26 (95%-CI 0–0.57) for TIR to 0.95 (95%-CI 0.87–0.98) for LCEA. Interobserver ICCs of manual measurements ranged from 0.43 (95%-CI 0.10–0.68) for AA to 0.95 (95%-CI 0.86–0.98) for LCEA. Intermethod ICCs ranged from 0.46 (95%-CI 0.12–0.70) for AA to 0.89 (95%-CI 0.78–0.94) for LCEA. Radiographic diagnostic agreement ranged from 47% to 100% for the manual observers and 63%–96% for the automated method as assessed by the radiologist. ConclusionThe automated algorithm performed equally well compared to manual measurement by trained observers, attesting to its reliability and efficiency in rapidly computing morphological measurements. This validated method can aid clinical practice and accelerate hip osteoarthritis research.

Femoral Anteversion Angle as a Predictor of Anterior Hip Labral Length in Patients With Femoroacetabular Impingement Syndrome.

The relationship between hip rotational abnormalities and hip labral size has not been fully investigated. To (1) examine the correlation between rotational abnormalities of the hip and labral size, while also identifying other predictive values for hip labral size, and (2) explore whether femoral torsion will lead to increased labral size. Cross-sectional study; Level of evidence, 3. A total of 180 patients (180 hips) with femoroacetabular impingement syndrome (FAIS) (mean age, 36.81 ± 10.17 years; 67 male, 113 female) who underwent hip arthroscopic surgery between January 2021 and May 2022 were included. The femoral version (FV), acetabular version, and combined version angles were measured on computed tomography, and the labral length and height at the 12-o'clock and 3-o'clock positions were measured on magnetic resonance imaging. The hips were categorized into 3 groups based on FV angle: small (SFV; <10°); moderate (MFV; ≥10° and ≤20°), and large (LFV; >20°), and group comparisons were performed. Linear correlation and regression analysis were employed. Predictive factors for labral length were FV angle (β = 0.298; P = .02), sex (β = -0.302; P < .001), and age (β = -0.169; P = .016) at 3 o'clock and lateral center-edge angle (LCEA; β = -0.208; P = .005) and age (β = -0.186; P = .011) at 12 o'clock. FV angle was positively correlated with labral length at 3 o'clock (r = 0.267; P < .001) and negatively correlated with age (r = -0.222; P = .003) and female sex (r = -0.202; P = .006). LCEA (r = -0.227; P = .002) and age (r = -0.205; P = .006) were negatively correlated with labral length at 12 o'clock. Labral length at 3 o'clock was significantly different between the LFV (n = 49 hips), MFV (n = 65 hips), and SFV (n = 66 hips) groups (9.85 ± 2.28, 8.89 ± 2.44, and 8.30 ± 2.05 mm, respectively; P = .027 for LFV vs MFV; P < .001 for LFV vs SFV). Patients with FAIS who exhibited a higher FV angle were at a greater likelihood of having a larger anterior labral length. Increased femoral anteversion and decreased LCEA, male sex, and younger age were significantly associated with longer hip labral length.

Patients With Dysplasia Achieve Similar Outcomes and Survivorship to Nondysplastic Patients 10 Years After Hip Arthroscopy for Femoroacetabular Impingement

To determine the long-term outcomes of hip arthroscopy (HA) for femoroacetabular impingement (FAI) in the presence of concomitant lateral rim dysplasia compared with a matched control group. Patients undergoing HA between January 2009 and October 2013 with minimum 10-year follow-up were reviewed. The inclusion criteria consisted of patients undergoing HA for FAI with evidence of lateral rim dysplasia (lateral-center edge angle [LCEA] < 25°). Patients with lateral rim dysplasia were matched to patients with an LCEA greater than 30° based on sex, Tönnis grade, and age. Outcomes included survival (avoidance of total hip replacement [THR]), repeated HA, and patient-reported outcomes (PROs). Survivorship was assessed using a Kaplan-Meier curve and log rank test, whereas revision rates between groups were assessed using χ2 analysis. Between- and within-group analyses of PROs were conducted using the Mann-Whitney U test and Wilcoxon signed rank test, respectively. The proportion of cases achieving the patient acceptable symptom state was compared between groups using χ2 analysis. This study comprised 46 dysplasia cases and 90 control cases. There was no statistically significant difference between groups in baseline metrics apart from the LCEA (P < .001), Sharp angle (P < .001), and Tönnis angle (P < .001). By 10 years postoperatively, 9% of dysplasia cases and 4% of control cases underwent conversion to THR. There was no statistically significant difference between groups in survival or revision rates. Both groups reported improvements in PROs, and there was no difference between PRO scores at either time point. Excluding cases that underwent THR, 84% and 83% of dysplasia and control cases, respectively, achieved the patient acceptable symptom state. HA for symptomatic FAI is a successful treatment in cases in which dysplasia is present. Low complication rates, comparable outcomes to cases without lateral rim dysplasia, and a high survivorship rate of 91% at minimum 10-year follow-up are observed. Increasing Tönnis angle preoperatively may increase the risk of THR conversion. Level IV, retrospective cohort study.

Radiological predictors of outcomes in hip arthroscopy for femoroacetabular impingement.

Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI. A prognostic cross-sectional cohort study was conducted involving patients from a single centre who underwent hip arthroscopy between January 2013 and April 2021. Radiological metrics measured on conventional radiographs and magnetic resonance arthrography were systematically assessed. The study analyzed the relationship between these metrics and complication rates, revision rates, and patient-reported outcomes. Out of 810 identified hip arthroscopies, 359 hips were included in the study. Radiological risk factors associated with unsatisfactory outcomes after cam resection included a dysplastic posterior wall, Tönnis grade 2 or higher, and over-correction of the α angle. The presence of acetabular retroversion and dysplasia were also significant predictors for worse surgical outcomes. Notably, over-correction of both cam and pincer deformities resulted in poorer outcomes than under-correction. We recommend caution in performing hip arthroscopy in patients who have three positive acetabular retroversion signs. Acetabular dysplasia with a lateral centre-edge angle of less than 20° should not be treated with isolated hip arthroscopy. Acetabular rim-trimming should be avoided in patients with borderline dysplasia, and care should be taken to avoid over-correction of a cam deformity and/or pincer deformity.

Generalized Joint Hypermobility Is Associated with Type-A Hip Dysplasia in Patients Undergoing Periacetabular Osteotomy.

Joint hypermobility may be associated with developmental dysplasia of the hip (DDH), but no definite conclusion has been reached. On the basis of long-term clinical observations, we hypothesized that joint hypermobility was associated with the occurrence, imaging findings, and clinical symptoms of DDH. We conducted a case-control study that included 175 Chinese Han patients between 13 and 45 years of age with Hartofilakidis type-A hip dysplasia. All of these patients underwent periacetabular osteotomy (PAO) between November 2021 and February 2023. An additional 76 individuals of comparable age and sex but without hip dysplasia were selected from the general population to serve as healthy controls. The Beighton 9-point scoring system was used to evaluate joint hypermobility, and a score of ≥4 was defined as generalized joint hypermobility. Standing anteroposterior pelvic radiographs were reviewed. For patients with DDH, the lateral center-edge angle, Tönnis angle, Sharp angle, lateralization of the femoral head, and patient-reported outcomes (iHOT-12, HHS, and WOMAC) were also collected to determine the radiographic severity or clinical symptoms of DDH. Patients with DDH had an elevated prevalence of generalized joint hypermobility compared with that in the healthy population (27% versus 12%; p = 0.009). Among patients with DDH, those with concomitant generalized joint hypermobility had lower lateral center-edge angles (3.55° versus 9.36°; p = 0.012), greater lateralization of the femoral head (13.78 versus 12.17 mm; p = 0.020), greater standardized lateralization of the femoral head (0.64 versus 0.54; p = 0.009), and lower iHOT-12 scores (35.22 versus 40.96; p = 0.009) than did those without concomitant generalized joint hypermobility. Further multivariable linear regression analysis revealed that higher Beighton scores and younger age were predictive of more severe hip dysplasia. However, the Beighton score was not found to be independently associated with patient-reported outcomes according to multivariable linear regression analysis. The prevalence of generalized joint hypermobility was greater in patients with DDH than in healthy controls. A higher degree of joint hypermobility was also correlated with more severe hip dysplasia. These results suggest that joint laxity, in addition to bone or cartilage factors, is an important factor related to DDH. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Combined assessment of acetabular coverage and femoral head-neck shapes predicts osteoarthritis progression after periacetabular osteotomy.

Postoperative osteoarthritis (OA) progression is a major determinant of failure after curved periacetabular osteotomy (CPO). A large postoperative combination angle, i.e., the combination of computed tomography-based anterior center edge and alpha angles, is associated with femoroacetabular impingement after CPO, but its association with postoperative OA progression is unclear. We aimed to identify the anatomical parameters that can lead to OA progression after CPO and the impact of the combination angle on the same. We included 90 hips that were subjected to CPO at our center between March 2013 and March 2018. Seventeen hips showed OA progression with an increase in the Tönnis classification after surgery; 73 hips showed no progression. Radiographic anatomical parameters, including the lateral and anterior center edge angles, femoral and acetabular anteversion, and combination angle, and clinical outcomes, including modified Harris Hip Scores (mHHSs), postoperative anterior impingement, and range of motion, were compared between the two groups. Statistical significance was set at P < 0.05. Postoperative OA progression was significantly affected by preoperative OA evidence (P = 0.017), acetabular anteversion < 5.0° (P = 0.003), and a combination angle > 107.0° (P = 0.025). Patients with radiographic OA progression were associated with poor mHHSs (P = 0.017) and high frequencies of anterior impingement with a limited hip flexion and internal rotation angle. OA progression after CPO may be associated with preoperative evidence of OA and postoperative acetabular retroversion as well as a large combination angle. Surgeons should focus on the potential effects of preoperative OA grades, postoperative reduction in acetabular anteversion, and postoperative combination angle.

Poster 203: Staged Hip Arthroscopy and Periacetabular Osteotomy Versus Hip Arthroscopy Alone in Patients with Borderline Hip Dysplasia: A Propensity-Matched Study

Objectives: The management of borderline hip dysplasia (BHD) remains an area of interest in the field of hip preservation. The purpose of this study was to (1) evaluate mean 2-year outcomes for patients with BHD treated with staged hip arthroscopy and periacetabular osteotomy (PAO) to those who underwent hip arthroscopy alone, and (2) evaluate rates of complications, hardware removal, reoperations, conversions to total hip arthroplasty (THA), along with conversions to PAO. Methods: Hips with a lateral center-edge angle (LCEA) values 18° ≤ LCEA &lt; 25° that underwent a hip arthroscopy for femoroacetabular impingement syndrome (FAIS) between January 2018 and June 2022 were reviewed. Patients who underwent staged periacetabular osteotomy and hip arthroscopy were identified. Staged hips were propensity-matched 1:4 to other borderline dysplastic hips that underwent hip arthroscopy alone. Matching was performed based on age, sex, and body-mass index (BMI). Patient-reported outcomes (PROs) were collected, including Hip Outcome Score – Activities of Daily Living (HOS-ADL), HOS-Sports Specific (HOS-SS) subscale, 12-item International Hip Outcome Tool (iHOT-12) questionnaire, Patient-Reported Outcomes Measurement Information System-Pain Interference (PROMIS-PI) subscale, and PROMIS-Physical Function (PROMIS-PF) subscale. Cohort-specific minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds were calculated. Postoperative PROs, rates of MCID/PASS achievement, and rates of reoperation and conversion to THA were compared. Results: Twenty-four patients who underwent staged hip arthroscopy and PAO were successfully matched to 96 patients who underwent hip arthroscopy alone. Both groups were similar in terms of age, sex, and BMI. The patients who underwent a PAO had smaller LCEAs and larger Tönnis angles (21.0° vs. 23° and 11.6° vs. 9.1°, respectively). Both groups demonstrated significant improvement in PROs at minimum 1-year postoperatively (p &lt; 0.001, for all). There were no significant differences in postoperative PRO scores between the groups (p ≥ 0.223, for all). There were no significant differences in MCID/PASS achievement (p ≥ 0.224. for all). There were no reoperations or conversion to THA in the staged hip arthroscopy and PAO group. In the hip arthroscopy alone cohort, reoperation rates were 5.2% and conversion to THA occurred in 1% of the patients. There were no significant differences in secondary surgery rates between the groups (p = 1.000). Three patients in the hip arthroscopy alone group ultimately underwent PAO, 1 underwent a proximal femoral osteotomy (PFO), and one underwent a revision hip arthroscopy. These female patients were young and athletic with an LCEA &lt; 20°. Conclusions: Patients undergoing staged PAO and hip arthroplasty and isolated hip arthroplasty for treatment of BHD demonstrate similar clinical improvement. Rates of revision surgery and conversion to THA were similarly low. A small subset of patients who were initially treated arthroscopically ultimately received a PAO. This group was entirely made up of young, athletic female patients. This is encouraging early data and more long-term data is needed to evaluate the differences in survivorship. [Figure: see text]

Poster 210: Flexible Athletes with Borderline Hip Dysplasia Achieve Successful and Similar Outcomes after Hip Arthroscopy Compared to Flexible Athletes without Borderline Hip Dysplasia

Objectives: To compare minimum 2-year patient-reported outcomes and achievement of clinically significant outcomes in flexibles athletes with and without borderline hip dysplasia (BHD) undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with capsular plication. Methods: Data was prospectively collected for patients undergoing primary hip arthroscopy for FAIS with borderline hip dysplasia (BHD), defined as a lateral center edge angle (LCEA) of 18° to 25°, with primary participation in a sport with high flexibility requirement including dance, gymnastics, figure skating, yoga, cheerleading, and martial arts. These patients were matched 1:2 to flexible athletes with an LCEA &gt;25° controlling for age, sex, body mass index (BMI) and follow up duration. Preoperative and minimum 2-year postoperative patient-reported outcomes included: Hip Outcome Score (HOS) Activities of Daily Living, HOS Sports Scale, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Cohort-specific Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) were calculated and compared between groups. Results: Fifty-two flexible athletes with BHD were matched to 104 flexible athletes without BHD. Similar sport participation (45% dance vs. 41%, p=0.874) and level of competition (74% vs. 74% recreational, p=0.877) were observed. Preoperative LCEA (22.2° ± 1.6 vs. 31.5° ± 3.9, p &lt; 0.001) and Tönnis angle (10.9 °± 3.7 vs. 5.8° ± 4.4, p &lt; 0.001) differed significantly between groups. Capsular plication was performed in all cases (100% and 100%, p = 1.000). Both groups achieved significant improvement in all PROs (p ≤ 0.001) with no differences in PROs between groups (p ≥ 0.147). High MCID (95.7%, 94.8%) and PASS (71.7%, 72.2%) achievement for any PRO was observed with no differences between groups (p ≥ 0.222). Conclusions: Flexible athletes with BHD achieve successful and similar outcomes to those without BHD after primary hip arthroscopy for FAIS with capsular plication.

Poster 218: Localized Acetabular Bone Density Distributions Are Altered in Unilateral Femoral Acetabular Impingement

Objectives: Femoral acetabular impingement (FAI) can lead to bony and cartilage changes at the joint, and it has been suggested that changes in bone mineral density in the acetabulum may correlate with osteoarthritic degeneration of the hip. In this study, we aimed to use opportunistic quantitative computed tomography (QCT) to map density distributions across the acetabular region in patients with unilateral FAI and determine if there were differences between the affected and unaffected side. Furthermore, we assessed if these differences in density distributions were associated with radiographic measures of FAI. Methods: Twenty patients (age 31.9 (SD 9.2), 13 female) who underwent surgery for unilateral FAI and had an associated CT scan of both hips were included in this retrospective study. Both sides of the pelvis were segmented, and 3D models were created. Estimated bone density values were mapped across the bone models via QCT. A thin-spline semi-landmarking approach was used to allow density values at equivalent anatomical points to be compared within patients and across the group. With the contralateral side used as the control, differences in bone density between sides were calculated. A mixed effect linear regression model was used to determine if there were associations between the localized bone density and radiographic measures of Tonnis grade, alpha angle, lateral center edge angle (LCEA), and cross over sign, while controlling for age and sex. To visualize the data, density changes and statistical results were color-mapped to the bone models. Results: Overall, several regions of the acetabulum were found to have increased bone density in the affected side compared to the contralateral (Figure 1). Specifically, the anterior-superior parts of the acetabular rim appeared to be most affected, along with the posterosuperior region (Figure 2). Limited associations were found between localized density and the clinical variables, with the most notable finding being a region of the superior rim that was found to be associated with the alpha angle (Figure 3). Conclusions: FAI leads to distinct patterns of bone density changes around the acetabulum, although there is still variability at the level of the individual patient. It is unclear whether these changes in bone density may be related to the underlying condition, alterations in the patient’s mechanics due to pain, or a combination of these factors. Providing detailed density maps of the bony anatomy may also assist surgical providers in planning interventions. Further research may elucidate the relationship between bone density changes and long-term degeneration of the joint.

Poster 181: Hip Arthroscopy with Concomitant Periacetabular Osteotomy Demonstrates Excellent Outcomes and Survivorship at Minimum 10-Year Follow-Up

Objectives: Multiple studies have shown that hip arthroscopy with concomitant periacetabular osteotomy (PAO) is a safe and effective treatment option for patients presenting with Symptomatic acetabular dysplasia and intra-articular pathology. While excellent short- and mid-term outcomes have been previously reported, there exists a paucity of literature investigating long-term outcomes of hip arthroscopy with concomitant PAO. The purpose of this study was to report minimum 10-year follow-up results and survivorship of hip arthroscopy with concomitant PAO to treat acetabular dysplasia and intraarticular pathologies such as femoroacetabular impingement (FAI) and labral tears. Methods: Data from October 2010 to December 2012 was prospectively collected and retrospectively reviewed to identify patients undergoing hip arthroscopy with concomitant PAO. Patients were included in the present analysis if they had preoperative and minimum 10-year patient reported outcomes (PROs) documented for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Scored Sports-Specific Subscale (HOS-SSS), and pain on a visual analog scale (VAS), as well as the International Hip Outcome Tool (iHOT-12) and patient satisfaction score on a 0-10 scale. Results: Fifteen patients were eligible for analysis and 12 had complete minimum 10-year follow-up (80.0%) at mean 10.2 years postoperation. There were 10 females (83.3%) and 2 males (16.7%) included in the study with a mean age and BMI of 24.4 years and 24.5 kg/m2, respectively. The mean lateral center-edge angle (LCEA) of all included hips in the analysis increased from 13.8° to 29.8° postoperatively ( P&lt;0.05) and the anterior center-edge angle (ACEA) increased from 14° to 28.8° postoperatively ( P&lt;0.05). Additionally, the Tönnis angle of acetabular inclination decreased from 17.9° to 7.3° postoperatively ( P&lt;0.05) and the alpha angle decreased from 56.5° to 52.1° postoperatively ( P&lt;0.05). There was significant improvement in all PROs from baseline to minimum 10-year follow-up (mHHS; NAHS; HOS-SSS, P&lt; 0.05). All patients achieved high rates of MCID for mHHS, NAHS, and HOS-SSS, as well as high rates of PASS for mHHS and VAS. The 10-year survivorship for all patients included in the analysis was 83.3% with 2 patients (16.7%) progressing to total hip arthroplasty (THA) at mean 58.0 months postoperatively. Additionally, 2 patients (16.7%) underwent subsequent ipsilateral revision hip arthroscopy at mean 79.5 months postoperatively. Conclusions: Patients with dysplasia and intra-articular pathology such as labral tears and FAI can be safely treated using hip arthroscopy with concomitant PAO. These patients can achieve excellent long-term outcomes and high rates of survivorship at minimum 10 years postoperation.

Paper 16: Long-term Outcomes of Primary Hip Arthroscopy: Multicenter Analysis at Minimum 10-Year Follow-Up with Attention to Labral and Capsular Management

Objectives: Hip arthroscopy is rapidly advancing, with literature increasingly reporting positive outcomes at short- and mid-term follow-up; however, available long-term data remains limited. The purpose of this study is to evaluate long-term outcomes of primary hip arthroscopy at minimum 10-year follow-up at two academic centers by describing patient-reported outcomes (PROs) and determining reoperation, revision, and total hip arthroplasty (THA) rates. Methods: Primary hip arthroscopies performed between January 1988 and April 2013 at 2 academic centers were evaluated for postoperative PROs including Visual Analogue Scale (VAS), Tegner Activity Scale score, Hip Outcome Score Activities of Daily Living and Sport Scale (HOS-ADL/HOS-SS), modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), 12-item International Hip Outcome Tool (iHOT-12), surgery satisfaction, function, and reoperations. Results: Two-hundred ninety-four primary hip arthroscopies with a mean age of 40±14 years; 66% female; and a mean body mass index (BMI) of 27±6 kg/m2 were followed for mean 12±3 years (range: 10-24). Labral debridement and repair were performed in 41% and 59% of patients, respectively. All patients underwent interportal capsulotomy and 2% underwent T-capsulotomy. Eleven percent of patients underwent capsular repair. At final follow-up, patients reported mean VAS at rest of 2±2, with use of 3±3, iHOT-12 of 68±27, NAHS of 81±18, mHHS of 79±17, HOS-ADL of 82±19, and HOS-SS of 74±25. Mean surgical satisfaction was 8.4±2.4 (Table 1). Sixty-five hips (23%) underwent THA and 33 (11%) underwent revision arthroscopy (Table 2). Risk factors for THA included older age (p&lt;0.001), higher BMI (p&lt;0.001), lower lateral center-edge angle (p=0.039), larger alpha angle (p=0.001), higher Tönnis grade (p=0.011), labral debridement (p=0.004), and capsular nonrepair (p=0.030). Patients undergoing combined labral and capsular repair demonstrated a THA conversion rate of 3% compared to 31% for patients undergoing combined labral debridement and capsular nonrepair (p=0.006) (Table 3). Labral repair trended towards increased 10-year THA-free survival (84% vs. 77%, p=0.085) while capsular repair demonstrated significantly increased 10-year THA-free survival (97% vs 79%, p=0.032) (Figure 1). Conclusions: At minimum 10-year follow-up, patients undergoing primary hip arthroscopy demonstrated high rates of satisfaction and acceptable outcome scores. In total, 11% of patients underwent revision hip arthroscopic surgery with a THA conversion rate of 23%. Conversion to THA was associated with patient factors including older age and higher Tönnis grade as well as potentially modifiable surgical factors including labral debridement and capsular nonrepair.

The Prevalence of Hip Dysplasia on Radiographs for Adolescent Idiopathic Scoliosis.

During radiographic assessment of adolescent idiopathic scoliosis (AIS), upright images frequently capture the hip. The purpose of this study was to assess the prevalence of radiographic hip dysplasia on postero-anterior (PA) scoliosis radiographs, as defined as a lateral center edge angle (LCEA) ≤25 degrees. All patients with upright PA scoliosis radiographs over a one-year study period at a single tertiary academic medical center (2020 to 2021) were included in the study. Radiographs containing the hip joints were annotated by 3 reviewers for left and right LCEA, and triradiate cartilage (TRC) status. Inter-rater reliability was determined among the 3 reviewers. Two hundred fifty patients {500 hips, 75.6% female, median age 14 [interquartile range (IQR)=3]} had PA scoliosis radiographs that captured the hip, which qualified for analysis. Seventy-four hips (14.8%) demonstrated evidence of dysplasia (LCEA ≤25 deg) in 55/250 patients (22%). The median LCEA was significantly lower in the dysplastic hip cohort (23.9 deg, IQR=4.8 deg), compared with those without dysplasia (33 deg IQR=7.3 deg; P =0.001). A higher percentage of dysplastic hip patients were female than male (72.7% vs. 27.3%). Patients with bilateral dysplasia had a similar LCEA ( 22.9 deg) [to those with unilateral dysplasia (22.9 deg left, 23.9 deg right, P =0.689)]. In a cohort of 250 AIS patients, 22% demonstrated evidence of hip dysplasia, as defined as an LCEA ≤2 degrees. The dysplastic patients were more likely to be female. Screening for hip symptomatology in AIS patients may be of benefit, considering the frequency of radiographic hip dysplasia in this population. III. Type of Evidence: diagnostic.

Long-term Survivorship and Outcomes of Patients Without Dysplasia Undergoing Capsular Repair During Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background: There is a paucity of literature evaluating long-term outcomes and survivorship of patients undergoing primary hip arthroscopy with capsular repair for femoroacetabular impingement syndrome (FAIS). Purpose: To report 10-year survivorship and patient-reported outcomes (PROs) after primary hip arthroscopy with capsular repair for FAIS and evaluate the effect of capsular repair in patients at the highest risk for conversion to arthroplasty. Study Design: Cohort study; Level of evidence, 3. Methods: Data were prospectively collected and retrospectively reviewed on all patients undergoing primary hip arthroscopy with capsular repair between October 2008 and February 2011. Patients with a minimum 10-year follow-up on the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and visual analog scale for pain (VAS) scores were selected. The preoperative and minimum 10-year follow-up Hip Outcome Score—Sports Specific Subscale (HOS-SSS) scores were also reported, if available. Patients with ipsilateral hip surgery, worker’s compensation, Tönnis osteoarthritis grade >1, and hip dysplasia (lateral center-edge angle <25°) were excluded. Survivorship, PROS, and clinical benefit—minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS)—were reported. An additional propensity-matched subanalysis was performed on patients at the highest risk for conversion to arthroplasty, comparing patients undergoing capsular repair to patients with unrepaired capsules. Results: A total of 145 (n = 130 patients) out of 180 eligible hips (n = 165 patients) had a minimum 10-year follow-up (80.6%). Also, 126 hips (86.9%) belonged to women, and 19 hips (13.1%) belonged to men. The mean patient age was 30.3 ± 12.9 years. The survivorship rate was 91% at the 10-year follow-up. The cohort experienced significant improvements (P < .001) in the mHHS, NAHS, HOS-SSS, and VAS for pain scores. Moreover, the cohort achieved high rates of the PASS for the mHHS (89.8%), high rates of the MCID for the mHHS (82.4%), and high rates of the MCID for VAS for pain (80.6%) scores. In the propensity-matched subanalysis performed on patients with the highest risk for arthroplasty, 29 hips with capsular repair were matched to 81 hips with unrepaired capsules. While both groups experienced significant improvements in all PROs (P < .05), the group without capsule repair trended toward a higher conversion to arthroplasty rate when compared with the repair group. In addition, an odds ratio was calculated for the likelihood of converting to arthroplasty after having an unrepaired capsule compared with capsular repair (2.54 [95% CI, 0.873-7.37]; P = .087). Conclusion: Patients undergoing primary hip arthroscopy with capsular repair experienced a high survivorship rate of 91% at a minimum 10-year follow-up. Patients who did not convert to arthroplasty saw favorable improvements in PROs and achieved high clinical benefit rates. In addition, among those patients at the highest risk for conversion to arthroplasty, a trend toward greater survivorship was observed with capsular repair.