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.

scholarly journals Acetabular Dysplasia: Three-Dimensional Deformity Predictors of the Diagnosis of Symptomatic Instability Treated with Periacetabular Osteotomy

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0042
Author(s):  
Maria Schwabe ◽  
Cecilia Pascual-Garrido ◽  
John Clohisy ◽  
Elizabeth Graesser ◽  
Jeffrey Nepple
Keyword(s):  
Low Dose ◽  
Acetabular Dysplasia ◽  
Periacetabular Osteotomy ◽  
Alpha Angle ◽  
Three Dimensional ◽  
Acetabular Coverage ◽  
Low Dose Ct ◽  
Femoral Version ◽  
Center Edge ◽  
Hip Morphology

Objectives: 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.

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]

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 MRI-based static and functional assessment of complex hip deformities in comparison with CT: a validation study

2020 ◽  
Vol 33 (6) ◽  
pp. 829-838
Author(s):  
Sophia Blum ◽  
Lea Franken ◽  
Albrecht Hartmann ◽  
Falk Thielemann ◽  
Verena Plodeck ◽  
...  
Keyword(s):  
Femoral Head ◽  
Linear Regression Analysis ◽  
Intraclass Correlation ◽  
Alpha Angle ◽  
Acetabular Coverage ◽  
Mri Findings ◽  
Perfect Agreement ◽  
Femoral Torsion ◽  
Center Edge ◽  
Hip Morphology

Abstract Objective This study aimed at investigating the agreement between predefined quantitative parameters of hip morphology derived from magnetic resonance imaging (MRI) and virtual range of motion (ROM) analysis using computed tomography (CT) as standard of reference. Methods Twenty patients (13 females, 7 males, 16–59 years) with hip deformities underwent MRI prior to surgery. Clockwise alpha angle, femoral head and neck diameter, collum caput diaphysis angle, femoral torsion, center-edge angles, acetabular coverage of the femoral head, sourcil angle, and acetabular anteversion were measured. Additionally, tern single and combined movements were simulated using a motion analysis program. The MRI findings were compared with the corresponding results obtained by CT. Correlation of MRI with CT was assessed using different statistical methods (intraclass correlation coefficient, Bland–Altmann plot, two one-sided t test), and linear regression analysis was performed. Results The results showed near-perfect intraclass correlation coefficients (ICCs) for anteversion (0.95), acetabular sector angles (0.98–0.99), sourcil angle (0.95), and acetabular coverage (anterior 0.96, posterior 0.99). Intermethod correlation for femoral parameters showed almost perfect agreement except for the alpha angle (0.73–0.97). No significant proportional bias was detected for traditional acetabular and femoral parameters. ROM analysis was performed for 370 movements in 37 hips. For 78.4% (290/370) of the movements analysed, neither CT nor MRI detected impingement across the physiological ROM. For 18.6% (69/370) of the movements, impingement was detected by both CT and MRI, while 2.2% (8/370) of the movements with impingement in CT showed no impingement in MRI, and 0.8% (3/370) of the movements with impingement in MRI had no corresponding result in CT. Conclusion Finally, it was concluded that MRI-based assessment of hip morphology and virtual ROM analysis is feasible and can be performed with good intermethod agreement in comparison to the gold standard (CT). Therefore, MRI appears to be substantially equivalent to CT for use in virtual ROM analysis and so may reasonably be used in place of CT for this purpose.

scholarly journals ASSESSMENT OF ACETABULAR COVERAGE IN BORDERLINE ACETABULAR DYSPLASIA: ARE PLAIN RADIOGRAPHIC PARAMETERS ACCURATELY ESTIMATES OF THREE-DIMENSIONAL COVERAGE?

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0020
Author(s):  
Elizabeth Graesser ◽  
Maria Schwabe ◽  
Sean Akers ◽  
Cecilia Pascual-Garrido ◽  
John C Clohisy ◽  
...  
Keyword(s):  
Femoral Head ◽  
Low Dose ◽  
Acetabular Dysplasia ◽  
Three Dimensional ◽  
Poor Correlation ◽  
Acetabular Coverage ◽  
Moderate Correlation ◽  
Femoral Head Coverage ◽  
Acetabular Inclination ◽  
The Mean

Introduction: Assessment of anterior acetabular coverage is commonly done with measurement of the anterior center edge angle (ACEA) or anterior wall index (AWI). This is particularly important in cases of borderline acetabular dysplasia where it may influence treatment decisions. However, the ACEA and AWI has been poorly validated. Purpose: The purpose of the current study was to investigate the correlation between plain radiographic measurements and three-dimensional femoral head coverage on low-dose CT in borderline acetabular dysplasia. Methods: Seventy consecutive hips with borderline acetabular dysplasia (LCEA 20-25°) were included in the current study. Radiographic evaluation was performed prospectively including LCEA, acetabular inclination, and AWI on AP pelvis radiographs, and ACEA on false profile radiographs. The mean LCEA was 22.1±1.4°, while the mean acetabular inclination was 10.3±3.3. All patients underwent low-dose pelvic CT assessment for preoperative planning. The radial acetabular coverage was calculated according to the standardized clock-face position [measured at 12:00 (lateral), 1:00, 2:00, 3:00 (anterior), and 4:00] as described by Larson et al. Statistical analysis determined the correlation between ACEA and radial coverage. Results: The mean ACEA in the group was 25.3±5.8° (range 10.1-43.9), with 16% having ACEA≤20° and 50% having ACEA≤25°. The mean radial coverages were 63.5%±1.7 (12:00), 60.7%±2.2 (1:00), 50.8%±3.2 (2:00), 37.0%±3.3 (3:00), and 27.9%±3.1 (4:00). The ACEA had poor correlation with radial coverage at all positions from 12:00 to 4:00 (range –0.068-0.173). The AWI had moderate correlation with radial coverage at 3:00 (PCC 0.499) and 4:00 (PCC 0.573). Comparing hips with an ACEA <20° versus >20°, there was no difference between the mean radial acetabular coverage at any position 12:00-4:00 (p=0.18-0.95). Comparing hips with an ACEA <25° versus >25°, there was no difference between the mean radial acetabular coverage at any position 12:00-4:00 (p=0.12-0.71). No significant difference in AWI was present between subgroups with normal and deficient radial coverage from 12:00 to 4:00 (p=0.09-0.72). Discussion: The current study demonstrates poor correlation of the ACEA measurement with true anterior femoral head coverage as evaluated at clock-face positions from 12:00 to 4:00. The AWI demonstrated moderate correlation for 3:00-4:00 coverage but fails to differentiate hips with normal and deficient coverage. In the setting of borderline acetabular dysplasia, anterior and anterolateral femoral coverage should be assessed via low-dose CT rather than ACEA or AWI.

scholarly journals LOW DOSE CT SCAN FOLLOWING PERIACETABULAR OSTEOTOMY: ASSESSMENT OF REDUCTION AND CORRELATION WITH RADIOGRAPHIC MEASURES

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0021
Author(s):  
Clarabelle DeVries ◽  
Jeffrey J Nepple ◽  
Lucas Fowler ◽  
Sean Akers ◽  
Gail Pashos ◽  
...  
Keyword(s):  
Femoral Head ◽  
Normative Data ◽  
Low Dose ◽  
Periacetabular Osteotomy ◽  
Femoral Head Coverage ◽  
Edge Angle ◽  
Center Edge ◽  
Two Sectors ◽  
Posterior Sector ◽  
Center Edge Angle

Introduction: Periacetabular osteotomy (PAO) has become a favored treatment for symptomatic acetabular dysplasia worldwide. Nevertheless, the parameters for optimal correction to avoid residual instability or iatrogenic impingement have not been defined. Purpose: The purposes of this study were (1) to assess the ability of PAO to correct femoral head coverage to normal ranges as measured by 3D CT scan and (2) to determine if postoperative radiographic parameters of dysplasia are accurate markers of optimal acetabular correction. Methods: A total of 43 hips (in 38 patients, mean 27.7 years, 88.4% female) were enrolled in this prospective cohort study at minimum 1 year after PAO. Postoperative femoral head coverage was assessed via low-dose CT and compared to normative data of asymptomatic hips from the literature. Anterior (3:00-1:15), lateral (1:00-11:00), and posterior (11:25-9:00) sector coverage was defined by averaging the coverage at 15 minute increments in each zone. Postoperative radiographs were utilized to measure lateral center edge angle (LCEA), anterior wall index (AWI), posterior wall index (PWI), and anterior center edge angle (ACEA). Good correction for each sector was defined as coverage from 1 SD below mean to 2 SD above mean. Results: Postoperatively, the anterior sector was normalized in 84% of hips, lateral sector in 84% of hips, and posterior sector in 86% of hips. Sixty-seven percent of hips were corrected to normative range in all three sectors and 19% were corrected in two sectors (86% in at least two sectors). LCEA and PWI showed the highest correlation with lateral and posterior sector coverage with Pearson’s correlation coefficients of 0.67 and 0.71 (p < 0.001), respectively. Weaker correlations were found between anterior coverage and the AWI and ACEA coverage (-0.16 and 0.15, respectively). Good correction was best correlated with the following target values for acetabular correction: LCEA 28°, AI 1°, AWI 0.37, ACEA 32°, and PWI 1.0. Conclusion: PAO can effectively normalize femoral head coverage compared to normative data. Good correction of each sector coverage ranged from 84-86% of cases. The proposed set of radiographic parameter targets were found to be reliable markers of femoral head coverage.

scholarly journals Acetabular morphology in slipped capital femoral epiphysis: comparison at treatment onset and skeletal maturity

2018 ◽  
Vol 12 (5) ◽  
pp. 444-453 ◽  
Author(s):  
D. A. Maranho ◽  
A. Davila-Parrilla ◽  
P. E. Miller ◽  
Y.-J. Kim ◽  
E. N. Novais ◽  
...  
Keyword(s):  
Acetabular Dysplasia ◽  
Skeletal Maturity ◽  
Slipped Capital Femoral Epiphysis ◽  
Alpha Angle ◽  
Width Ratio ◽  
Acetabular Coverage ◽  
Neck Shaft Angle ◽  
Factors Associated ◽  
Acetabular Morphology

Purpose To investigate changes in acetabular morphology during the follow-up of slipped capital femoral epiphysis (SCFE) and search for factors associated with acetabular dysplasia at skeletal maturity. Methods We evaluated 108 patients with unilateral SCFE (mean age at slip, 12.3 years sd 1.7) to skeletal maturity, with a minimum follow-up of two years (median 4.5 years; interquartile range 3.2 to 6.2). Acetabular parameters obtained from initial and most recent radiographs included the lateral centre-edge angle (LCEA), Tönnis angle (TA) and acetabular depth-width ratio (ADR). Acetabular dysplasia was considered for LCEA < 20° or TA > 10°. Femoral parameters consisted of the most recent head diameter, neck-shaft angle, neck length, articulotrochanteric distance and alpha angle. Results At SCFE onset, the affected hip showed a slightly lower LCEA (26.4° sd 6.1° versus 27.3° sd 5.7°; p = 0.01) and ADR (330 sd 30 versus 340 sd 30; p < 0.001) compared with the uninvolved hip. At final follow-up, the affected hip showed lower LCEA (24.5° sd 7.6° versus 28.8°sd 6.6°; p < 0.001) and ADR (330 sd 40 versus 350 sd 40; p < 0.001), and TA was larger (5.5° sd 5.4° versus 2.3° sd 4.2°; p < 0.001) compared with the uninvolved hip. Acetabular dysplasia was observed in 27 (25%) of 108 hips with SCFE. Femoral head overgrowth, age at slip and SCFE severity were independent factors associated with acetabular dysplasia (p < 0.05). Conclusion Acetabular coverage and depth are not increased in SCFE, and the acetabular coverage tends to decrease up to skeletal maturity. A potential disturbance in the acetabular growth and remodelling exists mainly for young children with severe SCFE, and a potential for acetabular insufficiency may be observed at the diagnosis and follow-up of SCFE. Level of Evidence Prognostic Level IV

scholarly journals Standard Radiographic Assessment of Femoral Cam Morphology is Influenced by Neck-Shaft Angle and Femoral Version

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0039
Author(s):  
Layla Haidar ◽  
Ryan Warth ◽  
Erinn Pemberton Annie Waite ◽  
Alfred Mansour
Keyword(s):  
Femoral Head ◽  
Alpha Angle ◽  
Three Dimensional ◽  
Neck Shaft Angle ◽  
Incremental Change ◽  
Observer Reliability ◽  
Angle Measurements ◽  
Femoral Version ◽  
Shaft Angle ◽  
Head Neck

Objectives: Cam-type femoroacetabular impingement (FAI) is a three-dimensional (3D) deformity that is still difficult to assess using traditional two-dimensional (2D) radiographic views. While measurements of alpha angle and head-neck offset are used to estimate the likelihood of actual impingement, these 2D measurements do not account for z-axis variations in femoral version (FV) and neck-shaft angle (NSA). The purpose of this qualitative proof-of-concept study was to evaluate the potential variation in alpha angle and neck-shaft offset measurements with incremental changes in NSA and FV by simulating traditional radiographic views with software-generated Digitally-Reconstructed Radiographs (DRRs). We hypothesize that incremental changes in hip morphology will produce qualitative changes in alpha angle and neck-shaft offset. Methods: 3D-CT reconstruction images were obtained from one subject with symptomatic cam-type FAI. The 3D reconstruction was cleaned to include only the femoral head, neck and subtrochanteric region along with the ipsilateral hemipelvis. Using 3D medical image processing software (Mimics; Materialise, Inc.; Belgium), the pre-processed 3D model was manipulated in a standardized manner to simulate 5-degree incremental variations in FV and NSA (-15 degrees to +15 degrees for FV; -15 degrees to +10 degrees for NSA). Negative FV reflected external rotation of the femoral head-neck unit, whereas negative NSA reflected abduction of the femoral head-neck unit. Each modified 3D model was then used to generate DRRs corresponding to traditional 2D radiographic views used for assessment of cam-FAI (Anteroposterior [AP], False Profile [FP]), Cross Table Lateral [CTL], Frog Leg Lateral [FLL], 45- and 90-degree Dunn [45D and 90D, respectively]. Alpha angle and head-neck offset were measured on each radiographic view corresponding to each incremental change in FV and NSA. All measurements utilized the perfect circle technique and were made by two independent observers for assessment of inter-observer reliability. Two-way random effects ANOVA was used for statistical assessment of inter-observer reliability and reported as intra-class correlation coefficients (κ). Comparisons between groups were performed using two-tailed paired t-tests assuming unequal variance. P-values less than 0.05 were considered statistically significant. Results: Inter-observer reliability (κ) for head-neck offset and alpha angles were 0.46 (fair) and 0.88 (excellent), respectively. Variations in head-neck offset and alpha angle with incremental variations in FV and NSA are summarized in Figure 1. There were statistically significant changes in mean alpha angles when the NSA was adjusted from Neutral to -5 degrees (p=0.01) and from -5 degrees to -10 degrees (p<0.001). There were no statistically significant differences in alpha angles or head-neck offsets between each incremental change in FV (p<0.05). Alpha angle measurements were significantly more variable than head-neck offset measurements for all variations in FV (p<0.001) and NSA (p=0.02) (Figure 2). Conclusion: Two-dimensional evaluation of three-dimensional Cam morphology (alpha angle and head-neck offset) was found to be significantly affected by alterations in femoral version and head-neck offset. Head-neck offset measurements were significantly less variable than alpha angle measurements across all FVs and NSAs within each radiographic view. Future work should be done to develop standardized procedures for routine 3D radiographic assessment of cam-type FAI. [Figure: see text][Figure: see text]

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.

Activity Level Maintenance at Midterm Follow-up Among Active Patients Undergoing Periacetabular Osteotomy

2019 ◽  
Vol 47 (14) ◽  
pp. 3455-3459
Author(s):  
Ugochi C. Okoroafor ◽  
Cecilia Pascual-Garrido ◽  
Maria T. Schwabe ◽  
Jeffrey J. Nepple ◽  
Perry L. Schoenecker ◽  
...  
Keyword(s):  
Acetabular Dysplasia ◽  
Periacetabular Osteotomy ◽  
Activity Levels ◽  
Center Edge ◽  
Ucla Score ◽  
The Mean ◽  
Symptomatic Acetabular Dysplasia ◽  
Active Patients ◽  
Center Edge Angle

Background: For active patients undergoing periacetabular osteotomy (PAO), returning to and maintaining a high level of activity postoperatively is a priority. Purpose: To evaluate the maintenance of activity levels at midterm follow-up in active patients treated with PAO for symptomatic acetabular dysplasia. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent PAO for symptomatic acetabular dysplasia between June 2006 and August 2013 were identified by a retrospective review of our prospective longitudinal institutional Hip Preservation Database. All patients with a preoperative University of California, Los Angeles (UCLA) score of ≥7 and a potential minimum 5 years of follow-up were included in the study. Functional outcome measures were the UCLA score, modified Harris Hip Score (mHHS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The maintenance of high activity levels was defined as a UCLA score of ≥7 at final follow-up. Radiographic parameters were measured. Statistical significance was defined as a P value <.05. Results: A total of 66 hips (58 patients) were included. The mean age was 25.3 years (range, 14-47 years), the mean body mass index was 23.9 kg/m2 (range, 19-32 kg/m2), and 72% were female. The mean follow-up was 6.8 years (range, 5-11 years). There were 67% of patients who maintained a UCLA score of ≥7. Patient-reported outcomes improved postoperatively from preoperatively for the mHHS (88 ± 14 vs 67 ± 17, respectively; P < .001) and WOMAC (89 ± 15 vs 73 ± 20, respectively; P < .001). The lateral center-edge angle, anterior center-edge angle, and acetabular inclination were significantly improved at final follow-up ( P < .001). Only 4 patients (7%) cited postoperative activity limitations as being caused by hip pain. There were no conversions to total hip arthroplasty. Conclusion: The majority (67%) of active patients returned to preoperative or higher activity levels after PAO at midterm follow-up.

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