Do acetabular parameters measured on 2D imaging correlate with CT, and can lateral centre-edge angle predict femoral head coverage?

Aims The lateral centre-edge angle (LCEA) is a plain radiological measure of superolateral cover of the femoral head. This study aims to establish the correlation between 2D radiological and 3D CT measurements of acetabular morphology, and to describe the relationship between LCEA and femoral head cover (FHC). Methods This retrospective study included 353 periacetabular osteotomies (PAOs) performed between January 2014 and December 2017. Overall, 97 hips in 75 patients had 3D analysis by Clinical Graphics, giving measurements for LCEA, acetabular index (AI), and FHC. Roentgenographical LCEA, AI, posterior wall index (PWI), and anterior wall index (AWI) were measured from supine AP pelvis radiographs. The correlation between CT and roentgenographical measurements was calculated. Sequential multiple linear regression was performed to determine the relationship between roentgenographical measurements and CT FHC. Results CT-measured LCEA and AI correlated strongly with roentgenographical LCEA ( r = 0.92; p < 0.001) and AI ( r = 0.83; p < 0.001). Radiological LCEA correlated very strongly with CT FHC ( r = 0.92; p < 0.001). The sum of AWI and PWI also correlated strongly with CTFHC ( r = 0.73; p < 0.001). CT measurements of LCEA and AI were 3.4° less and 2.3° greater than radiological LCEA and AI measures. There was a linear relation between radiological LCEA and CT FHC. The linear regression model statistically significantly predicted FHC from LCEA, F(1,96) = 545.1 (p < 0.001), adjusted R2 = 85.0%, with the prediction equation: CT FHC(%) = 42.1 + 0.77(XRLCEA) Conclusion CT and roentgenographical measurement of acetabular parameters are comparable. Currently, a radiological LCEA greater than 25° is considered normal. This study demonstrates that those with hip pain and normal radiological acetabular parameters may still have deficiencies in FHC. More sophisticated imaging techniques such as 3D CT should be considered for those with hip pain to identify deficiencies in FHC. Cite this article: Bone Jt Open 2022;3(1):12–19.

Correlation between full-thickness degenerative supraspinatus tear and radiographic parameters including the acromiohumeral centre edge angle and the greater tuberosity angle

Background Many radiographic parameters associated with the extrinsic cause of supraspinatus tears have been proposed. The aim of this study was to assess the relationship between a full-thickness degenerative supraspinatus tear (FTDST) and the patient’s radiographic parameters, including the acromiohumeral centre edge angle (ACEA) and the greater tuberosity angle (GTA). Methods A retrospective study was conducted. We included 116 patients who underwent shoulder arthroscopic surgery at our institute. The case group included FTDST patients, whereas the control group also included patients without evidence of supraspinatus tears. In each patient, the ACEA and GTA values were measured and analyzed by two independent observers. Intra- and interobserver reliabilities were assessed. Multivariate regression analysis was performed. Results The ACEA values were significantly increased in the FTDST group with a mean of 26.44° ± 9.83° compared with 16.81° ± 7.72° in the control group (P < 0.001). Multivariate regression analysis also showed that higher ACEA values were associated with an FTDST (odds ratio 1.16 per degree, P = 0.01). For GTA values, a statistically significant difference was found with a mean of 70.92° ± 6.64 compared with 67.84° ± 5.56 in the control group (P = 0.02). However, stepwise regression analysis did not indicate that GTA was a predictor of FTDST. Conclusions Our study demonstrated that the presence of increased ACEA values is an independent significant risk factor for the presence of FTDSTs. Consequently, GTA values may be less helpful in assessing the risk of FTDST, especially in this specific population.

Reliability and sensitivity of radiographic measures of hip dysplasia in childhood Charcot-Marie-Tooth disease

Background: Hip dysplasia is a lack of femoral head coverage and disruption of hip and acetabular alignment and congruency, with severity ranging from mild subluxation in nascent at-risk hips to complete dislocation. Presentation of hip dysplasia in neuromuscular conditions can be sub-clinical or associated with a limp with or without hip pain, abductor and flexor weakness and reduced hip range of motion. Untreated hip dysplasia leads to early onset osteoarthritis requiring hip arthroplasty in early adulthood. Hip dysplasia occurs in 6–20% of children with Charcot-Marie-Tooth disease, however little is known about the reliability and sensitivity of detection on plain film pelvic radiographs. Methods: 14 common measures of hip dysplasia on anteroposterior pelvis radiographs were independently assessed by 2 orthopaedic specialists in 30 ambulant children with Charcot-Marie-Tooth disease. Hip health was also categorised based on clinical impression to assess the sensitivity of radiographic measures to identify hip dysplasia status. Results: 8 measures (acetabular index, head width, lateral centre-edge angle, lateral uncoverage, medial joint width, migration percentage, neck shaft angle, triradiate status) exhibited ‘excellent’ reliability between clinical evaluators. 5 of the 30 patients (17%) were identified as having nascent hip dysplasia. Reliable radiographic measures that significantly distinguished between nascent hip dysplasia and healthy hips were acetabular index, lateral centre edge angle, medial joint width and migration percentage. Conclusions: We have identified a subset of reliable and sensitive radiographic hip measures in children with Charcot-Marie-Tooth disease to prioritise during hip screening to mitigate the deleterious effects of hip dysplasia, pain and disability in adulthood.

Do Acromiohumeral Centre Edge Angle and Greater Tuberosity Angle Correlate With the Full-Thickness Degenerative Supraspinatus Tear?

Background: Many radiographic parameters associated with the extrinsic cause of supraspinatus tear have been proposed. The aim of this study was to correlate the relationship between full-thickness degenerative supraspinatus tear (FTDST) and the patient’s radiographic parameters, including the acromiohumeral centre edge angle (ACEA) and the greater tuberosity angle (GTA).Methods: A retrospective study was conducted. We included 116 patients who had undergone shoulder arthroscopic surgery at our institute. The case group included FTDST patients, while the control group also included patients without evidence of supraspinatus tear. In each patient, the ACEA and GTA values were measured and analysed by two independent observers. Intra-inter observer reliability was assessed. Multivariate regression analysis was performed.Results: The ACEA values were significantly higher in FTDST, with a mean of 26.44°± 9.83° compared with 16.81° ± 7.72° in the control group (P < 0.001). Multivariate regression analysis also showed that higher ACEA values were associated with a FTDST (odds ratio 1.16 per degree, P = 0.01). Meanwhile, for GTA values, a statistically significant difference was found with a mean of 70.92° ± 6.64 compared with 67.84° ± 5.56 in the control group (P = 0.02). However, Stepwise regression analysis rejected GTA as a predictor for FTDST.Conclusions: Our study demonstrated that the presence of higher ACEA values is an independent significant risk factor for the presence of FTDST. Consequently, GTA values may be less helpful in assessing the risk of FTDST, especially in this specific population.

Anterior centre-edge angle on sagittal CT: a comparison of normal hips to dysplastic hips

Purpose: The anterior centre-edge angle (ACEA) describes anterior acetabular coverage on false profile radiographs. Variability associated with pelvic tilt, radiographic projection, and identifying the true anterior edge, causes discrepancies in measuring an accurate ACEA. Computed tomography (CT) has the potential of improving the accuracy of ACEA. However, because the ACEA on sagittal CT has been shown to not be equivalent to ACEA on false profile radiographs, the normal range of ACEA on CT currently remains unknown and cannot reliably be used to determine over/under coverage. We therefore asked: what is the normal variation of ACEA corrected for pelvic tilt on sagittal CT and how does this compare to dysplastic hips? Material and Methods: A retrospective review was conducted on patients 10–35 who underwent CT for non-orthopedic related issues and patients with known hip dysplasia. The ACEA was measured on a sagittal slice corresponding to the centre of the femoral head on the axial slice and adjusted for pelvic tilt. A statistical comparison was then performed. Results: A total of 320 normal patients and 22 patients with hip dysplasia were reviewed. The mean ACEA for all ages was 50° ± 8°, (range: 23–81º), with a larger mean ACEA for males (51°) than females (49°). The ACEA mean for dysplastic hips was 30° ± 11° with a statistically significant difference in mean from the normal hip group ( p < 0.0001). Conclusion: The ACEA can be reliably measured on sagittal CT and significantly differs from dysplastic hips. ACEA measurements above 66° or below 34° may represent anterior over and under coverage.

Factors Predicting the Outcomes of Incomplete Triple Pelvic Osteotomy

Introduction In the present study, we identified factors affecting the outcomes of patients who underwent incomplete triple pelvic osteotomies due to acetabular dysplasia. Methods Data on a total of 58 hips in 50 patients for whom adequate data were available and who had undergone appropriate follow-up were retrospectively evaluated. We used Ömeroğlu scores for radiological evaluation, Harris Hip Scores for clinical evaluation, Tönnis scores to evaluate osteoarthritis progression and a modified Clavien-Dindo classification to evaluate complications. Results The average patient age was 23.26 (14-47) years, and the average follow-up duration 105.59 (18-191) months. The complication rate was 10.3%, and complications negatively influenced clinical outcomes. Patients with radiologically poorer outcomes had more advanced osteoarthritis. We found minimal improvements in lateral centre edge angle (LCEA), refined centre-edge angle (RCEA), and lateral acetabulum head index (LAHI) were associated with osteoarthritis progression and that good improvements in LCEA, RCEA, acetabular angle (AA), and LAHI were associated with radiological outcomes. Neither patient age at the time of operation nor development of a postoperative relative crossover sign affected osteoarthritis progression or clinical or radiological outcomes. Conclusions The most important factors influencing clinical outcomes were complications. However, neither postoperative acetabular retroversion nor a positive supra-equatorial crossover sign (often viewed as prognostically negative) directly affected clinical outcomes. When treating patients with acetabular dysplasia, either inadequate correction or overcorrection may negatively affect outcomes. In such patients, an incomplete triple pelvic osteotomy (allowing controlled correction) is both safe and effective.

Transpositional Periacetabular Osteotomy with Allografting in Patients with Severe Dysplasia: Mid-Term Results

Aim The purpose of this study was to analyse the extent of surgical correction and the early clinical results obtained using periacetabular osteotomy with allogenic bone grafting in patients with severe acetabular dysplasia. Methods 44 hips in 38 patients were confirmed to have severe acetabular dysplasia and underwent this procedure. The mean follow-up period was 4.2 (range 1.5-8.2) years. Severe acetabular dysplasia was defined as a centre-edge angle less than 0°, an acetabular-head index less than 50% and an acetabular roof obliquity greater than 30°. Periacetabular osteotomy was performed with transpositional osteotomy of the acetabulum. The patients were divided into 2 groups according to the radiographic appearance: 34 hips in the early stage group and 10 hips in the advanced stage group. Postoperatively, the hips were radiographically assessed for dysplasia correction. The clinical results and hip function were measured using the Harris Hip Score. Results The average pre-operative Harris Hip Score improved from 70 to 91 points at the latest follow-up. The average centre-edge angle, acetabular-head index and acetabular roof obliquity improved from −9° to 36°, 41% to 91% and 31° to 2°, respectively. Continuity of the Shenton line improved from 15 to 35 hips. No instances of nonunion or of transported segment collapse were encountered in this series; however, a grafted allogenic bone was absorbed in 1 case. Conclusions The usage of allogenic bone grafting combined with periacetabular osteotomy is an effective technique for treating severe acetabular dysplasia. In this series, the early clinical and radiographic results were excellent.