scholarly journals Development and External Validation of a Novel Clinical Score to Quantify the Presence of Instability Characteristics in Patients with Borderline Acetabular Dysplasia

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0043
Author(s):  
Elizabeth Graesser ◽  
Lee Rhea ◽  
Cecilia Pascual-Garrido ◽  
John Clohisy ◽  
Jeffrey Nepple ◽  
...  
Keyword(s):  
Acetabular Dysplasia ◽  
External Validation ◽  
Alpha Angle ◽  
Hip Instability ◽  
Discriminatory Ability ◽  
Edge Angle ◽  
C Statistic ◽  
Center Edge ◽  
Center Edge Angle ◽  
Multicenter Prospective Cohort

Objectives: Treatment of borderline acetabular dysplasia is controversial. The existing literature lacks direct comparisons of different treatment approaches and focuses on lateral center edge angle (LCEA), failing to account for other important diagnostic characteristics. The purpose of this study was (1) to determine the most important characteristics in determining hip instability in this population, and (2) to develop a nomogram for clinical use and calculation of the Borderline Hip Instability Score (BHIS), and (3) to externally validate the BHIS in a multicenter prospective cohort of patients with borderline acetabular dysplasia. Methods: The current study included two parts. In Part 1, this study utilized a retrospective cohort study of 186 hips (178 patients) undergoing surgical treatment in setting of borderline acetabular dysplasia (LCEA 20°-25°) from a single surgeon experienced in arthroscopic and open techniques. Patients were excluded if over 40 years of age, Tonnis grade ≥2, prior ipsilateral surgery, or residual pediatric or neuromuscular disease. Multivariate analysis determined characteristics associated with presence of instability (treated with PAO +/- hip arthroscopy) or absence of instability (treated with isolated hip arthroscopy) based on clinical diagnosis of the single surgeon. During the study period, 39.8% of the cohort underwent PAO. Multivariate analysis with bootstrapping was performed and results were transformed into a nomogram and BHIS (higher score representing more instability). In Part 2, the BHIS was externally validated in a cohort of 114 patients with borderline acetabular dysplasia enrolled in a multicenter prospective cohort study across 10 other surgeons (with varied treatment approaches from arthroscopy to open procedures). Results: In Part 1, the most parsimonious and best fit model included 4 variables associated with instability: acetabular inclination (AI), anterior center edge angle (ACEA), maximum alpha angle, and internal rotation in 90 degrees of flexion (IRF). Odds ratio estimates and 95% confidence limits were 1.50 (1.28-1.76), 0.92 (0.86-0.99), 0.94 (0.90-0.98), and 1.11 (1.07-1.17), respectively. Notably, sex and LCEA were not significant predictors. The BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. Mean BHIS in the population was 50.0 (instability 57.7 ±7.9 vs. non-instability 44.8±7.3, p<0.001). BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. In Part 2, BHIS maintained excellent c-statistic=0.92 in external validation. Mean BHIS in this cohort was 53.9 (instability 66.5±11.5 vs. non-instability 43.0±10.8, p<0.001). Conclusion: In patients with borderline acetabular dysplasia, AI, ACEA, maximum alpha angle, and IRF were key factors in diagnosing significant instability treated with PAO. The BHIS effectively quantifies relative role of each factor and characterizes aspects of instability compared to the mean (BHIS=50) in this population. The BHIS score allowed for good differentiation of patients with and without instability in the development cohort, as well as the external validation cohort. Use of the BHIS score may facilitate efficient clinical characterization of important patient characteristics in the setting of borderline acetabular dysplasia.

scholarly journals DEVELOPMENT AND EXTERNAL VALIDATION OF A NOVEL CLINICAL SCORE TO QUANTIFY THE PRESENCE OF INSTABILITY CHARACTERISTICS IN PATIENTS WITH BORDERLINE ACETABULAR DYSPLASIA

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0020
Author(s):  
Maria Schwabe ◽  
Elizabeth Graesser ◽  
Lee Rhea ◽  
Cecilia Pascual-Garrido ◽  
John C Clohisy ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Cohort Study ◽  
Acetabular Dysplasia ◽  
External Validation ◽  
Alpha Angle ◽  
Clinical Score ◽  
Edge Angle ◽  
C Statistic ◽  
Center Edge ◽  
Center Edge Angle

Background Treatment of borderline acetabular dysplasia (BD) is controversial with some patients having primarily instability-based symptoms while others have impingement-based symptoms. The existing literature lacks direct comparisons of different treatment approaches, and generally fails to report other important diagnostic characteristics beyond the lateral center edge angle (LCEA). Purpose The purpose of this study was (1) to identify the most important patient characteristics influencing the diagnosis of instability vs. non-instability, (2) to develop a clinical score (Borderline Hip Instability Score, BHIS) to collectively characterize these factors and (3) to externally validate BHIS in a multicenter cohort BD patients. Methods In Part 1, this study utilized a retrospective cohort study of 186 hips undergoing surgical treatment of BD (LCEA 20°-25°) from a single surgeon experienced in arthroscopic and open techniques. Multivariate analysis determined characteristics associated with presence of instability (treated with PAO +/- hip arthroscopy) or absence of instability (treated with isolated hip arthroscopy) based on clinical diagnosis of the single surgeon. During the study period, 39.8% of the cohort underwent PAO. Multivariate analysis with bootstrapping was performed and results were transformed into a BHIS nomogram (higher score representing more instability). In Part 2, BHIS was externally validated in 114 BD patients enrolled in a multicenter prospective cohort study across 10 surgeons (with varied treatment approaches from arthroscopy to open procedures). Results In Part 1, the most parsimonious, best fit model included 4 variables associated with the diagnosis of instability: acetabular inclination (AI), anterior center edge angle (ACEA), maximum alpha angle, and internal rotation in 90 degrees of flexion (IRF). Sex and LCEA were not significant predictors. Mean BHIS in the population was 50.0 (instability 57.7 ±7.9; non-instability 44.8±7.3, p<0.001). BHIS demonstrated excellent predictive (discriminatory) ability with c-statistic=0.89. In Part 2, BHIS maintained excellent c-statistic=0.92 in external validation. Mean BHIS in the external cohort was 53.9 (instability 66.5±11.5; non-instability 43.0±10.8, p<0.001). Discussion In patients with BD, key factors in diagnosing significant instability treated with PAO were AI, ACEA, maximum alpha angle, and IRF. The BHIS score allowed for differentiation of patients with and without instability in the development and external validation cohort.

scholarly journals DEFINING THE BORDERLINE HIP: HIGH VARIABILITY IN ACETABULAR COVERAGE AND FEMORAL DEFORMITY

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0021
Author(s):  
Elizabeth Graesser ◽  
Maria Schwabe ◽  
Cecilia Pascual-Garrido ◽  
John C Clohisy ◽  
Jeffrey J Nepple
Keyword(s):  
Low Dose ◽  
Acetabular Dysplasia ◽  
Alpha Angle ◽  
Acetabular Coverage ◽  
Edge Angle ◽  
Femoral Version ◽  
Center Edge ◽  
Femoral Deformity ◽  
The Mean ◽  
Center Edge Angle

Introduction Borderline acetabular dysplasia is radiographically defined as a lateral center edge angle (LCEA) of 20-25 degrees. It is well accepted that some borderline hips have instability while others have primarily impingement. The optimal management of borderline dysplasia is challenging and particularly complex due to the anatomic variability that exists among patients but has not been well characterized. Purpose The purpose of this current study was to investigate the variability in hip deformity present on low-dose CT in a cohort of patients with symptomatic borderline acetabular dysplasia. Methods Seventy consecutive hips with borderline acetabular dysplasia undergoing surgical treatment were included in the current study. Radiographic evaluation included LCEA, acetabular inclination, anterior center edge angle (ACEA), and alpha angles on AP, Dunn, and frog views. All patients underwent low-dose pelvic CT for preoperative planning. Femoral deformity was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Radial acetabular coverage was calculated according to standardized clock-face positions [measured from 8:00 (posterior) to 4:00 (anterior)] and defined as normal, under-coverage, or over-coverage relative to 1 SD from the mean of normative values. Results The mean LCEA was 22.1±1.4, while the mean acetabular inclination was 10.3±3.3. The mean ACEA in the group was 25.3±5.8 (range 10.1-43.9), with 16% having an ACEA ≤ 20 and 50% having an ACEA ≤ 25. The mean femoral version was 17.9° (range -4° to 59°). The mean maximal alpha angle was 57.2° (range 43° to 81°) with 61.4% greater than 55°. Lateral coverage (RAC at 12:00) was deficient in 74.1% of cases. Anterior coverage (RAC at 2:00) was highly variable with 17.1% under-coverage, 72.9% normal, and 10.0% over-coverage. Posterior coverage (RAC at 10:00) was also highly variable with 30.0% under-coverage, 62.9% normal, and 7.1% over-coverage. The three most common patterns of coverage were: isolated lateral under-coverage (31.4%), normal coverage (18.6%), and lateral and posterior under-coverage (17.1%). Discussion Patients with borderline acetabular dysplasia demonstrate highly variable three-dimensional deformities including anterior, lateral, and posterior acetabular coverage, femoral version, and alpha angle. Comprehensive deformity characterization in the population is important to guide diagnosis and treatment decisions.

scholarly journals Defining the Borderline Hip: High Variability in Acetabular Coverage and Femoral Deformity

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0034
Author(s):  
Maria Schwabe ◽  
Cecilia Pascual-Garrido ◽  
John Clohisy ◽  
Elizabeth Graesser Jeffrey Nepple
Keyword(s):  
Low Dose ◽  
Acetabular Dysplasia ◽  
Alpha Angle ◽  
Acetabular Coverage ◽  
Femoral Version ◽  
Center Edge ◽  
Text Figure ◽  
Femoral Deformity ◽  
The Mean ◽  
Center Edge Angle

Objectives: Borderline acetabular dysplasia is radiographically defined as a lateral center edge angle (LCEA) of 20-25 degrees. It is well accepted that some borderline hips have instability while others have primarily impingement. The optimal management of borderline dysplasia is challenging and particularly complex due to the anatomic variability that exists among patients but has not been well characterized. The purpose of this current study was to investigate the variability in hip deformity present on low-dose CT in a cohort of patients with symptomatic borderline acetabular dysplasia. Methods: Seventy consecutive hips with borderline acetabular dysplasia undergoing surgical treatment were included in the current study. Radiographic evaluation included LCEA, acetabular inclination, anterior center edge angle (ACEA), and alpha angles on AP, Dunn, and frog views. All patients underwent low-dose pelvic CT for preoperative planning. Femoral deformity was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Radial acetabular coverage was calculated according to standardized clockface positions [measured from 8:00 (posterior) to 4:00 (anterior)] and defined as normal, undercoverage, or overcoverage relative to 1 SD from the mean of normative values. Results: The mean LCEA was 22.1+1.4, while the mean acetabular inclination was 10.3+3.3. The mean ACEA in the group was 25.3+5.8 (range 10.1-43.9), with 16% having an ACEA < 20 and 50% having an ACEA < 25. The mean femoral version was 17.9° (range -4° to 59°). The mean maximal alpha angle was 57.2° (range 43° to 81°) with 61.4% greater than 55°. Lateral coverage (RAC at 12:00) was deficient in 74.1% of cases. Anterior coverage (RAC at 2:00) was highly variable with 17.1% undercoverage, 72.9% normal, and 10.0% overcoverage. Posterior coverage (RAC at 10:00) was also highly variable with 30.0% undercoverage, 62.9% normal, and 7.1% overcoverage. The three most common patterns of coverage were: isolated lateral undercoverage (31.4%), normal coverage (18.6%), and lateral and posterior undercoverage (17.1%). Conclusion: Patients with borderline acetabular dysplasia demonstrate highly variable three-dimensional deformities including anterior, lateral, and posterior acetabular coverage, femoral version, and alpha angle. Comprehensive deformity characterization in the population is important to guide diagnosis and treatment decisions. [Figure: see text][Figure: see text][Figure: see text]

Radiographic Indices Are Not Predictive of Clinical Outcomes Among 1735 Patients Indicated for Hip Arthroscopic Surgery: A Machine Learning Analysis

2020 ◽  
Vol 48 (12) ◽  
pp. 2910-2918 ◽  
Author(s):  
Prem N. Ramkumar ◽  
Jaret M. Karnuta ◽  
Heather S. Haeberle ◽  
Spencer W. Sullivan ◽  
Danyal H. Nawabi ◽  
...  
Keyword(s):  
Machine Learning ◽  
Arthroscopic Surgery ◽  
Alpha Angle ◽  
Harris Hip Score ◽  
Edge Angle ◽  
Hip Impingement ◽  
Femoral Version ◽  
Center Edge ◽  
Center Edge Angle

Background: The relationship between the preoperative radiographic indices for femoroacetabular impingement syndrome (FAIS) and postoperative patient-reported outcome measure (PROM) scores continues to be under investigation, with inconsistent findings reported. Purpose: To apply a machine learning model to determine which preoperative radiographic indices, if any, among patients indicated for the arthroscopic correction of FAIS predict whether a patient will achieve the minimal clinically important difference (MCID) for 1- and 2-year PROM scores. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 1735 consecutive patients undergoing primary hip arthroscopic surgery for FAIS were included from an institutional hip preservation registry. Patients underwent preoperative computed tomography of the hip, from which the following radiographic indices were calculated by a musculoskeletal radiologist: alpha angle, beta angle, sagittal center-edge angle, coronal center-edge angle, neck shaft angle, acetabular version angle, and femoral version angle. PROM scores were collected preoperatively, at 1 year postoperatively, and at 2 years postoperatively for the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS)–Activities of Daily Living (HOS-ADL) and –Sport Specific (HOS-SS), and the International Hip Outcome Tool (iHOT-33). Random forest models were created for each PROM at 1 and 2 years’ follow-up, with each PROM’s MCID used to establish clinical meaningfulness. Data inputted into the models included ethnicity, laterality, sex, age, body mass index, and radiographic indices. Comprehensive and separate models were built specifically to assess the association of the alpha angle, femoral version angle, coronal center-edge angle, McKibbin index, and hip impingement index with respect to each PROM. Results: As evidenced by poor area under the curves and P values >.05 for each model created, no combination of radiographic indices or isolated index (alpha angle, coronal center-edge angle, femoral version angle, McKibbin index, hip impingement index) was a significant predictor of a clinically meaningful improvement in scores on the mHHS, HOS-ADL, HOS-SS, or iHOT-33. The mean difference between 1- and 2-year PROM scores compared with preoperative values exceeded the respective MCIDs for the cohort. Conclusion: In patients appropriately indicated for FAIS corrective surgery, clinical improvements can be achieved, regardless of preoperative radiographic indices, such as the femoral version angle, coronal center-edge angle, and alpha angle. No specific radiographic parameter or combination of indices was found to be predictive of reaching the MCID for any of the 4 studied hip-specific PROMs at either 1 or 2 years’ follow-up.

scholarly journals What Are the Reference Values and Associated Factors for Center-edge Angle and Alpha Angle? A Population-based Study

2018 ◽  
Vol 476 (11) ◽  
pp. 2249-2259 ◽  
Author(s):  
Cornelius Sebastian Fischer ◽  
Jens-Peter Kühn ◽  
Till Ittermann ◽  
Carsten-Oliver Schmidt ◽  
Denis Gümbel ◽  
...  
Keyword(s):  
Reference Values ◽  
Associated Factors ◽  
Alpha Angle ◽  
Population Based ◽  
Population Based Study ◽  
Edge Angle ◽  
Center Edge ◽  
Center Edge Angle

scholarly journals Sex dimorphism of postural parameters of the human acetabulum

2011 ◽  
Vol 63 (1) ◽  
pp. 137-143
Author(s):  
D. Jeremic ◽  
B. Jovanovic ◽  
Ivana Zivanovic-Macuzic ◽  
Gordana Djordjevic ◽  
Maja Sazdanovic ◽  
...  
Keyword(s):  
Gender Differences ◽  
Acetabular Dysplasia ◽  
Acetabular Roof ◽  
Sex Dimorphism ◽  
Edge Angle ◽  
Centre Edge Angle ◽  
Acetabular Angle ◽  
Center Edge ◽  
Acetabular Morphology ◽  
Center Edge Angle

The aim of this investigation was to examine normal acetabular morphometry, its sex dimorphism and the acetabular dysplasia rate in Serbian adults. For each hip, the centre-edge angle of Wiberg, the acetabular angle of Sharp, acetabular depth and acetabular roof obliquity were measured. The center-edge angle of Wiberg correlated negatively with the acetabular angle of Sharp and acetabular roof obliquity, but positively correlated with acetabular depth. Our results suggest that the prevalence of acetabular dysplasia in the Serbian population is lower than in Western countries. We confirmed the existence of significant gender differences in acetabular morphology among the subjects of our study. These sex-related differences in acetabular morphology were the cause for more dysplastic female acetabula compared with male acetabula.

scholarly journals Hip center edge angle and alpha angle correlate with gait variables in femoroacetabular impingement morphology (919.11)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Gary Farkas ◽  
Marc Haro ◽  
Simon Lee ◽  
Alejandro Espinoza Orias ◽  
Shane Nho
Keyword(s):  
Femoroacetabular Impingement ◽  
Alpha Angle ◽  
Edge Angle ◽  
Center Edge ◽  
Center Edge Angle

scholarly journals BORDERLINE ACETABULAR DYSPLASIA: THREE-DIMENSIONAL DEFORMITY PREDICTORS OF THE DIAGNOSIS OF SYMPTOMATIC INSTABILITY TREATED WITH PERIACETABULAR OSTEOTOMY

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0016
Author(s):  
Elizabeth Graesser ◽  
Maria Schwabe ◽  
Cecilia Pascual Garrido ◽  
John C. Clohisy ◽  
Jeffrey J. Nepple
Keyword(s):  
Low Dose ◽  
Acetabular Dysplasia ◽  
Periacetabular Osteotomy ◽  
Alpha Angle ◽  
Three Dimensional ◽  
Acetabular Coverage ◽  
Low Dose Ct ◽  
Femoral Version ◽  
Center Edge ◽  
Hip Morphology

Introduction: Borderline acetabular dysplasia is classically defined as a lateral center edge angle (LCEA) of 20-25 degrees. The optimal treatment strategy in this patient group remains controversial, with some patients having primarily hip instability-based symptoms, while others have primarily impingement-based symptoms (non-instability). The purpose of the current study was to define the 3D characteristics on low-dose CT that differentiate patients with instability symptoms from those without instability in the setting of borderline acetabular dysplasia. Methods: Seventy consecutive hips with borderline acetabular dysplasia undergoing surgical treatment were included in the current study. All patients underwent low-dose pelvic CT with femoral version assessment for preoperative planning. CT measurements included alpha angle and radial acetabular coverage (RAC) at standardized clockface positions (9:00-posterior to 3:00-anterior), central and cranial acetabular version. RAC was assessed in three sectors (anterior, superior, and posterior) and defined (relative to published normative data) as normal (-1 SD, +1 SD), undercoverage (<-1 SD), or overcoverage (>+1 SD). Statistical analysis was performed to compare the CT characteristics of the symptomatic instability and non-instability groups. Results: Of the 70 hips, 62.9% had the diagnosis of symptomatic instability, while 37.1% had no instability symptoms. Hips with instability (compared to non-instability) had significantly lower alpha angle (maximal difference at 1:00 - 47.0° vs. 59.4°), increased femoral version (22.3° vs. 15.3°), and decreased radial acetabular coverage (maximal difference at 1:00 – 59.9% vs. 62.2%) (all p<0.001). Multivariate analysis identified femoral version (OR 1.1, p=0.02), alpha angle at 1:00 (OR 0.91, p=0.02), and RAC at 1:00 (OR 0.46, p=0.003) as independent predictors of the presence of instability. The model combining these three factors had excellent predictive probability with a c-statistic 0.92. Conclusion: We found significant differences in the 3D hip morphology of the symptomatic instability and non-instability subgroups within the borderline dysplasia cohort. In the setting of borderline dysplasia, three-dimensional deformity characterization with low-dose CT allowed for differentiation of patients diagnosed with underlying instability vs. non-instability. Femoral version, alpha angle at 1:00, and radial acetabular coverage at 1:00 were identified as independent predictors of diagnosis in borderline acetabular dysplasia. Summary: This study attempts to define 3D CT characteristics to help distinguish between patients with impingement-based vs instability-based symptoms of borderline acetabular dysplasia.

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