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 R. 2. = 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

Aims. Hip dysplasia (HD) leads to premature osteoarthritis. Timely detection and correction of HD has been shown to improve pain, functional status, and hip longevity. Several time-consuming radiological measurements are currently used to confirm HD. An artificial intelligence (AI) software named HIPPO automatically locates anatomical landmarks on anteroposterior pelvis radiographs and performs the needed measurements. The primary aim of this study was to assess the reliability of this tool as compared to multi-reader evaluation in clinically proven cases of adult HD. The secondary aims were to assess the time savings achieved and evaluate inter-reader assessment. Methods. A consecutive preoperative sample of 130 HD patients (256 hips) was used. This cohort included 82.3% females (n = 107) and 17.7% males (n = 23) with median patient age of 28.6 years (interquartile range (IQR) 22.5 to 37.2). Three trained readers’ measurements were compared to AI outputs of lateral centre-edge angle (LCEA), caput-collum-diaphyseal (CCD) angle, pelvic obliquity, Tönnis angle, Sharp’s angle, and femoral head coverage. Intraclass correlation coefficients (ICC) and Bland-Altman analyses were obtained. Results. Among 256 hips with AI outputs, all six hip AI measurements were successfully obtained. The AI-reader correlations were generally good (ICC 0.60 to 0.74) to excellent (ICC > 0.75). There was lower agreement for CCD angle measurement. Most widely used measurements for HD diagnosis (LCEA and Tönnis angle) demonstrated good to excellent inter-method reliability (ICC 0.71 to 0.86 and 0.82 to 0.90, respectively). The median reading time for the three readers and AI was 212 (IQR 197 to 230), 131 (IQR 126 to 147), 734 (IQR 690 to 786), and 41 (IQR 38 to 44) seconds, respectively. Conclusion. This study showed that AI-based software demonstrated reliable radiological assessment of patients with HD with significant interpretation-related time savings. Cite this article: Bone Jt Open 2022;3(11):877–884

Aims. Periacetabular osteotomy (PAO) is an established treatment for acetabular dysplasia. It has also been proposed as a treatment for patients with acetabular retroversion. By reviewing a large cohort, we aimed to test whether outcome is equivalent for both types of morphology and identify factors that influenced outcome. Methods. A single-centre, retrospective cohort study was performed on patients with acetabular retroversion treated with PAO (n = 62 hips). Acetabular retroversion was diagnosed clinically and radiologically (presence of a crossover sign, posterior wall sign, lateral centre-edge angle (LCEA) between 20° and 35°). Outcomes were compared with a control group of patients undergoing PAO for dysplasia (LCEA < 20°; n = 86 hips). Femoral version was recorded. Patient-reported outcome measures (PROMs), complications, and reoperation rates were measured. Results. The mean Non-Arthritic Hip Score (NAHS) preoperatively was 58.6 (SD 16.1) for the dysplastic hips and 52.5 (SD 12.7) for the retroverted hips (p = 0.145). Postoperatively, mean NAHS was 83.0 (SD 16.9) and 76.7 (SD 17.9) for dysplastic and retroverted hips respectively (p = 0.041). Difference between pre- and postoperative NAHS was slightly lower in the retroverted hips (18.3 (SD 22.1)) compared to the dysplastic hips (25.2 (SD 15.2); p = 0.230). At mean 3.5 years’ follow-up (SD 1.9), one hip needed a revision PAO and no hips were converted to total hip arthroplasty (THA) in the retroversion group. In the control group, six hips (7.0%) were revised to THA. No differences in complications (p = 0.106) or in reoperation rate (p = 0.087) were seen. Negative predictors of outcome for patients undergoing surgery for retroversion were female sex, obesity, hypermobility, and severely decreased femoral anteversion. Conclusion. A PAO is an effective surgical intervention for acetabular retroversion and produces similar improvements when used to treat dysplasia. Femoral version should be routinely assessed in these patients and when extremely low (< 0°), as an additional procedure to address this abnormality may be necessary. Females with signs of hypermobility should also be consulted of the likely guarded improvement. Cite this article: Bone Jt Open 2021;2(9):757–764

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Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty.

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Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon.

Acetabular retroversion is a recognised cause of hip impingement. Pelvic tilt influences acetabular orientation and is known to change in different functional positions. While previously reported in patients with developmental dysplasia of the hip, positional changes in pelvic tilt have not been studied in patients with acetabular retroversion. We retrospectively analysed supine and standing AP pelvic radiographs in 22 patients with preoperative radiographs and 47 with post-operative radiographs treated for symptomatic acetabular retroversion. Measurements were made for acetabular index (AI), lateral centre-edge angle (LCEA), crossover index, ischial spine sign, and posterior wall sign. The change in pelvic tilt angle was measured both by the Sacro-Femoral-Pubic (SFP) angle and the Pubic Symphysis to Sacro-iliac (PS-SI) Index. In the supine position, the mean calculated pelvic tilt angle (by SFP) was 1.05° which changed on standing to a pelvic tilt of 8.64°. A significant increase in posterior pelvic tilt angle from supine to standing of 7.59° (SFP angle) and 5.89° (PS –SI index) was calculated (p<0.001;paired t-test). There was a good correlation in pelvic tilt change between measurements using SFP angle and PS-SI index (rho .901 in pre-op group, rho .815 in post-op group). Signs of retroversion were significantly reduced in standing x-rays compared to supine: Crossover index (0.16 vs 0.38; p<0.001) crossover sign (19/28 vs 28/28 hips; p<0.001), ischial spine sign (10/28 hips vs 26/28 hips; p<0.001) and posterior wall sign (12/28 vs 24/28 hips; p<0.001). Posterior pelvic tilt increased from supine to standing in patients with symptomatic acetabular retroversion, in keeping with previous studies of pelvic tilt change in patients with hip dysplasia. The features of acetabular retroversion were much less evident on standing radiographs. The low pelvic tilt angle in the supine position is implicated in the appearance of acetabular retroversion in the supine position. Patients presenting with symptoms of hip impingement should be assessed by supine and standing pelvic radiographs so as not to miss signs of retroversion and to assist with optimising acetabular correction at the time of surgery

Acetabular retroversion is a recognised cause of hip impingement. Pelvic tilt influences acetabular orientation and is known to change in different functional positions. While previously reported in patients with developmental dysplasia of the hip, positional changes in pelvic tilt have not been studied in patients with acetabular retroversion. We retrospectively analysed supine and standing AP pelvic radiographs in 22 patients with preoperative radiographs and 47 with post-operative radiographs treated for symptomatic acetabular retroversion. Measurements were made for acetabular index (AI), lateral centre-edge angle (LCEA), crossover index, ischial spine sign, and posterior wall sign. The change in pelvic tilt angle was measured both by the Sacro-Femoral-Pubic (SFP) angle and the Pubic Symphysis to Sacro-iliac (PS-SI) Index. In the supine position, the mean calculated pelvic tilt angle (by SFP) was 1.05° which changed on standing to a pelvic tilt of 8.64°. A significant increase in posterior pelvic tilt angle from supine to standing of 7.59° (SFP angle) and 5.89° (PS –SI index) was calculated (p<0.001;paired t-test). The mean pelvic tilt change of 6.51° measured on post-operative Xrays was not significantly different (p=.650). There was a good correlation in pelvic tilt change between measurements using SFP angle and PS-SI index (rho .901 in pre-op group, rho .815 in post-op group). Signs of retroversion were significantly reduced in standing x-rays compared to supine: Crossover index (0.16 vs 0.38; p<0.001) crossover sign (19/28 vs 28/28 hips; p<0.001), ischial spine sign (10/28 hips vs 26/28 hips; p<0.001) and posterior wall sign (12/28 vs 24/28 hips; p<0.001). Posterior pelvic tilt increased from supine to standing in patients with symptomatic acetabular retroversion, in keeping with previous studies of pelvic tilt change in patients with hip dysplasia. The features of acetabular retroversion were much less evident on standing radiographs. The low pelvic tilt angle in the supine position is implicated in the appearance of acetabular retroversion in the supine position. Patients presenting with symptoms of hip impingement should be assessed by supine and standing pelvic radiographs so as not to miss signs of retroversion and to assist with optimising acetabular correction at the time of surgery

Periacetabular osteotomy (PAO) has been established as an effective technique to treat symptomatic hip dysplasia in young patients. Its role in treating borderline dysplasia and acetabular retroversion is evolving. The aim of this study was to:. Examine the prospectively collected outcomes following a minimally invasive PAO in a large cohort of patients. Compare the outcomes of patients with severe dysplasia, borderline dysplasia and acetabular retroversion. This is a single-surgeon review of patients operated in a high-volume centre with prospectively collected data between 2013 and 2020, and minimal followup of six months. PAO was performed using a minimally invasive modified Smith Peterson approach. 387 patients were operated during the study period and 369 eligible patients included in the final analysis. Radiographic parameters were assessed by two authors (GS and KB) with interrater reliability for 25 patients of 84–95% (IntraClass Coefficient). Patient reported outcome measures (i-HOT 12, NAHS, UCLA and EQ-5D) were collected prospectively. Case note review was also performed to collate complication data and blood transfusion rates. Radiological parameters improved significantly after surgery with Lateral centre-edge angle (LCEA) improving by 16.4 degrees and Acetabular index (AI) improved by 15.8 degrees. Patient reported outcome measures showed significant improvement in post-op NAHS, iHOT and EQ5D at 2 years compared to pre-op scores (NAHS=30.45, iHOT=42, EQ5D=0.32, p=0.01). This significance is maintained over 2 years post procedure (p=0.001). There was no significant difference between the three groups (severe dysplasia, borderline dysplasia and acetabular retroversion). Clinical outcomes showed an overall complication rate n=31, 8.3% (Major complication rate: n=3, 0.81%). Non-union rate: n=11, 2.96% of which 3 required fixation (0.81%). Hip arthroscopy post PAO: n=7, 1.9%. Conversion to THR: n=4, 1.1%. Blood transfusion requirement: n=46, 12.5%. No patient developed a major neurovascular injury. In this large single-centre study, patients had radiological and reported outcome improvements following surgery. Overall, there was a low complication rate, providing further evidence of the safety and efficacy of PAO for ameliorating pain and long-lasting results in the management of symptomatic hip dysplasia

The definition of osseous instability in radiographic borderline dysplastic hips is difficult. A reliable radiographic tool that aids decision-making specifically, a tool that might be associated with instability-therefore would be very helpful for this group of patients. The aims of this study were:. (1) To compare a new radiographic measurement, which we call the Femoro-Epiphyseal Acetabular Roof (FEAR) index, with the lateral centre-edge angle (LCEA) and acetabular index (AI), with respect to intra- and interobserver reliability; (2) to correlate AI, neck-shaft angle, LCEA, iliocapsularis volume, femoral antetorsion, and FEAR index with the surgical treatment received instable and unstable borderline dysplastic hips; and (3) to assess whether the FEAR index is associated clinical instability in borderline dysplastic hips. We defined and validated the FEAR index in 10 standardized radiographs of asymptomatic controls using two blinded independent observers. Interrater and intrarater coefficients were calculated, supplemented by Bland-Altman plots. We compared its reliability with LCEA and AI. We performed a case-control study using standardized radiographs of 39 surgically treated symptomatic borderline radiographically dysplastic hips and 20 age-matched controls with asymptomatic hips (a 2:1 ratio), the latter were patients attending our institution for trauma unrelated to their hips but who had standardized pelvic radiographs between January 1, 2016 and March 1, 2016. Patient demographics were assessed using univariate Wilcoxon two-sample tests. There was no difference in mean age (overall: 31.5 ± 11.8 years [95% CI, 27.7–35.4 years]; stable borderline group: mean, 32.1± 13.3 years [95%CI, 25.5–38.7 years]; unstable borderline group: mean, 31.1 ± 10.7 years [95% CI, 26.2–35.9 years]; p = 0.96) among study groups. Treatment received was either a periacetabular osteotomy (if the hip was unstable) or, for patients with femoroacetabular impingement, either an open or arthroscopic femoroacetabular impingement procedure. The association of received treatment categories with the variables AI, neck-shaft angle, LCEA, iliocapsularis volume, femoral antetorsion, and FEAR index were evaluated first using Wilcoxon two-sample tests (two-sided) followed by stepwise multiple logistic regression analysis to identify the potential associated variables in a combined setting. Sensitivity, specificity, and receiver operator curves were calculated. The primary endpoint was the association between the FEAR index and instability, which we defined as migration of the femoral head either already visible on conventional radiographs or recentering of the head on AP abduction views, a break of Shenton's line, or the appearance of a crescent-shaped accumulation of gadolinium in the posteroinferior joint space at MR arthrography. The FEAR index showed excellent intra- and interobserver reliability, superior to the AI and LCEA. The FEAR index was lower in the stable borderline group (mean, −2.1 ± 8.4; 95% CI, −6.3 to 2.0) compared with the unstable borderline group (mean, 13.3 ± 15.2; 95% CI, 6.2–20.4) (p < 0.001) and had the highest association with treatment received. A FEAR index less than 5° had a 79% probability of correctly assigning hips as stable and unstable, respectively (sensitivity 78%; specificity 80%). A painful hip with a LCEA of 25° or less and FEAR index less than 5° is likely to be stable, and in such a situation, the diagnostic focus might more productively be directed toward femoroacetabular impingement

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We assessed the long-term outcomes of a large cohort of patients who have undergone a periacetabular osteotomy (PAO), and sought to validate a patient satisfaction questionnaire for use in a PAO cohort.

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This study aimed to investigate the incidence of ≥ 5 mm asymmetry in lower and whole leg lengths (LLs) in patients with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH-OA) and primary hip osteoarthritis (PHOA), and the relationship between lower and whole LL asymmetries and femoral length asymmetry.

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Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters.

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The primary aim of this study was to determine the ten-year outcome following surgical treatment for femoroacetabular impingement (FAI). We assessed whether the evolution of practice from open to arthroscopic techniques influenced outcomes and tested whether any patient, radiological, or surgical factors were associated with outcome.