Aims. To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. Methods. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora. Results. Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version (r > 0.46; p < 0.001) and greater NSA (r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°). Conclusion. Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences. Cite this article: Bone Jt Open 2022;3(10):759–766

Aims. The aim of this study was to perform a cross-cultural adaptation of Oxford Hip Score (OHS) to Indonesian, and to evaluate its psychometric properties. Methods. We performed a cross-cultural adaptation of Oxford Hip Score into Indonesian language (OHS-ID) and determined its internal consistency, test-retest reliability, measurement error, floor-ceiling effect, responsiveness, and construct validity by hypotheses testing of its correlation with Harris Hip Score (HHS), vsual analogue scale (VAS), and Short Form-36 (SF-36). Adults (> 17 years old) with chronic hip pain (osteoarthritis or osteonecrosis) were included. Results. A total of 125 patients were included, including 50 total hip arthroplasty (THA) patients with six months follow-up. The OHS questionnaire was translated into Indonesian and showed good internal consistency (Cronbach’s alpha = 0.89) and good reliability (intraclass correlation = 0.98). The standard error of measurement value of 2.11 resulted in minimal detectable change score of 5.8. Ten out of ten (100%) a priori hypotheses were met, confirming the construct validity. A strong correlation was found with two subscales of SF-36 (pain and physical function), HHS (0.94), and VAS (-0.83). OHS-ID also showed good responsiveness for post-THA series. Floor and ceiling effect was not found. Conclusion. The Indonesian version of OHS showed similar reliability and validity with the original OHS. This questionnaire will be suitable to assess chronic hip pain in Indonesian-speaking patients. Cite this article: Bone Jt Open 2021;2(9):765–772

Objectives. The Oxford hip score (OHS) is a 12-item questionnaire designed and developed to assess function and pain from the perspective of patients who are undergoing total hip replacement (THR). The OHS has been shown to be consistent, reliable, valid and sensitive to clinical change following THR. It has been translated into different languages, but no adequately translated, adapted and validated Danish language version exists. Methods. The OHS was translated and cross-culturally adapted into Danish from the original English version, using methods based on best-practice guidelines. The translation was tested for psychometric quality in patients drawn from a cohort from the Danish Hip Arthroplasty Register (DHR). Results. The Danish OHS had a response rate of 87.4%, no floor effect and a 19.9% ceiling effect (as expected in post-operative patients). Only 1.2% of patients had too many items missing to calculate a sum score. Construct validity was adequate and 80% of our predefined hypotheses regarding the correlation between scores on the Danish OHS and the other questionnaires were confirmed. The intraclass correlation (ICC) of the different items ranged from 0.80 to 0.95 and the average limits of agreement (LOA) ranged from -0.05 to 0.06. The Danish OHS had a high internal consistency with a Cronbach’s alpha of 0.99 and an average inter-item correlation of 0.88. Conclusions. This Danish version of the OHS is a valid and reliable patient-reported outcome measurement instrument (PROM) with similar qualities to the original English language version.

Aims

The aim of this study was to identify the optimal lip position for total hip arthroplasties (THAs) using a lipped liner. There is a lack of consensus on the optimal position, with substantial variability in surgeon practice.

Aims. The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?. Methods. A retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high acetabular anteversion (20 hips) were analyzed. Statistical analysis was performed using analysis of variance with Bonferroni correction. Results. PI and PT were significantly decreased comparing AR (PI 42° (SD 10°), PT 4° (SD 5°)) with dysplastic hips (PI 55° (SD 12°), PT 10° (SD 6°)) and with the control group (PI 51° (SD 9°) and PT 13° (SD 7°)) (p < 0.001). External rotation of the iliac wing was significantly increased comparing AR (29° (SD 4°)) with dysplastic hips (20°(SD 5°)) and with the control group (25° (SD 5°)) (p < 0.001). Correlation between external rotation of the iliac wing and acetabular version was significant and strong (r = 0.81; p < 0.001). Correlation between PT and acetabular version was significant and moderate (r = 0.58; p < 0.001). Conclusion. These findings could contribute to a better understanding of hip pain in a sitting position and extra-articular subspine FAI of patients with AR. These patients have increased iliac external rotation, a rotational abnormality of the iliac wing. This has implications for surgical therapy with hip arthroscopy and acetabular rim trimming or anteverting periacetabular osteotomy (PAO). Cite this article: Bone Jt Open 2021;2(10):813–824

Aims. Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients. Methods. A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method). Results. Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o’clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion. Conclusion. Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex. Cite this article: Bone Joint Res 2023;12(1):22–32

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

Aims. Psychological status may be an important predictor of outcome after periacetabular osteotomy (PAO). The aim of this study was to investigate the influence of psychological distress on postoperative health-related quality of life, joint function, self-assessed pain, and sports ability in patients undergoing PAO. Methods. In all, 202 consecutive patients who underwent PAO for developmental dysplasia of the hip (DDH) at our institution from 2015 to 2017 were included and followed up at 63 months (SD 10) postoperatively. Of these, 101 with complete data sets entered final analysis. Patients were assessed by questionnaire. Psychological status was measured by Brief Symptom Inventory (BSI-18), health-related quality of life was raised with 36-Item Short Form Survey (SF-36), hip functionality was measured by the short version 0f the International Hip Outcome Tool (iHOT-12), Subjective Hip Value (SHV), and Hip Disability and Outcome Score (HOS). Surgery satisfaction and pain were assessed. Dependent variables (endpoints) were postoperative quality of life (SF-36, HOS quality of life (QoL)), joint function (iHOT-12, SHV, HOS), patient satisfaction, and pain. Psychological distress was assessed by the Global Severity Index (GSI), somatization (BSI Soma), depression (BSI Depr), and anxiety (BSI Anx). Influence of psychological status was assessed by means of univariate and multiple multivariate regression analysis. Results. In multiple multivariate regression, postoperative GSI, BSI Soma, and BSI Depr had a negative effect on postoperative SF-36 (e -2.07, -3.05, and -2.67, respectively; p < 0.001), iHOT-12 (e -1.35 and -4.65, respectively; p < 0.001), SHV (e -1.20 and -2.71, respectively; p < 0.001), HOS QoL (e -2.09 and -4.79, respectively; p < 0.001), HOS Function (e -1.00 and -3.94, respectively; p < 0.001), and HOS Sport (e -1.44 and -5.29, respectively; p < 0.001), and had an effect on postoperative pain (e 0.13 and 0.37, respectively; p < 0.001). Conclusion. Psychological distress, depression, and somatization disorders affect health-related quality of life, perceived joint function, and sports ability. Pain perception is significantly increased by somatization. However, patient satisfaction with surgery is not affected. Cite this article: Bone Jt Open 2023;4(10):758–765

Aims. The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes. Methods. A retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed. Results. A significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°). Conclusion. Patients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation. Cite this article: Bone Jt Open 2022;3(7):557–565

Aims. Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane. Methods. Postoperative CT scans of 40 patients who underwent unilateral uncemented total hip arthroplasty were analyzed. Anteroposterior offset (APO) and femoral anteversion were measured on both the operated and non-operated sides. Sagittal tilt of the femoral stem was also measured. APO measured on axial slices was defined as the perpendicular distance between a line drawn from the anterior most point of the proximal femur (anterior reference line) to the centre of the femoral head. The anterior reference line was made parallel to the posterior condylar axis of the knee to correct for rotation. Results. Overall, 26/40 hips had a centre of rotation displaced posteriorly compared to the contralateral hip, increasing to 33/40 once corrected for sagittal tilt, with a mean posterior displacement of 7 mm. Linear regression analysis indicated that stem anteversion needed to be increased by 10.8° to recreate the head centre in the AP plane. Merely matching the native version would result in a 12 mm posterior displacement. Conclusion. This study demonstrates the significant incidence of posterior displacement of the head centre in uncemented hip arthroplasty. Effects of such displacement include a reduction in impingement free range of motion, potential alterations in muscle force vectors and lever arms, and impaired proprioception due to muscle fibre reorientation. Cite this article: Bone Joint Res 2022;11(3):180–188

Aims. Traditionally, acetabular component insertion during total hip arthroplasty (THA) is visually assisted in the posterior approach and fluoroscopically assisted in the anterior approach. The present study examined the accuracy of a new surgeon during anterior (NSA) and posterior (NSP) THA using robotic arm-assisted technology compared to two experienced surgeons using traditional methods. Methods. Prospectively collected data was reviewed for 120 patients at two institutions. Data were collected on the first 30 anterior approach and the first 30 posterior approach surgeries performed by a newly graduated arthroplasty surgeon (all using robotic arm-assisted technology) and was compared to standard THA by an experienced anterior (SSA) and posterior surgeon (SSP). Acetabular component inclination, version, and leg length were calculated postoperatively and differences calculated based on postoperative film measurement. Results. Demographic data were similar between groups with the exception of BMI being lower in the NSA group (27.98 vs 25.2; p = 0.005). Operating time and total time in operating room (TTOR) was lower in the SSA (p < 0.001) and TTOR was higher in the NSP group (p = 0.014). Planned versus postoperative leg length discrepancy were similar among both anterior and posterior surgeries (p > 0.104). Planned versus postoperative abduction and anteversion were similar among the NSA and SSA (p > 0.425), whereas planned versus postoperative abduction and anteversion were lower in the NSP (p < 0.001). Outliers > 10 mm from planned leg length were present in one case of the SSP and NSP, with none in the anterior groups. There were no outliers > 10° in anterior or posterior for abduction in all surgeons. The SSP had six outliers > 10° in anteversion while the NSP had none (p = 0.004); the SSA had no outliers for anteversion while the NSA had one (p = 0.500). Conclusion. Robotic arm-assisted technology allowed a newly trained surgeon to produce similarly accurate results and outcomes as experienced surgeons in anterior and posterior hip arthroplasty. Cite this article: Bone Jt Open 2021;2(6):365–370

Objectives. The spinopelvic relationship (including pelvic incidence) has been shown to influence pelvic orientation, but its potential association with femoroacetabular impingement has not been thoroughly explored. The purpose of this study was to prove the hypothesis that decreasing pelvic incidence is associated with increased risk of cam morphology. Methods. Two matching cohorts were created from a collection of cadaveric specimens with known pelvic incidences: 50 subjects with the highest pelvic incidence (all subjects > 60°) and 50 subjects with the lowest pelvic incidence (all subjects < 35°). Femoral version, acetabular version, and alpha angles were directly measured from each specimen bilaterally. Cam morphology was defined as alpha angle > 55°. Differences between the two cohorts were analysed with a Student’s t-test and the difference in incidence of cam morphology was assessed using a chi-squared test. The significance level for all tests was set at p < 0.05. Results. Cam morphology was identified in 47/100 (47%) femurs in the cohort with pelvic incidence < 35° and in only 25/100 (25%) femurs in the cohort with pelvic incidence > 60° (p = 0.002). The mean alpha angle was also greater in the cohort with pelvic incidence < 35° (mean 53.7°, . sd. 10.7° versus mean 49.7°, . sd. 10.6°; p = 0.008). Conclusions. Decreased pelvic incidence is associated with development of cam morphology. We propose a novel theory wherein subjects with decreased pelvic incidence compensate during gait (to maintain optimal sagittal balance) through anterior pelvic tilt, creating artificial anterior acetabular overcoverage and recurrent impingement that increases risk for cam morphology. Cite this article: W. Z. Morris, C. A. Fowers, R. T. Yuh, J. J. Gebhart, M. J. Salata, R. W. Liu. Decreasing pelvic incidence is associated with greater risk of cam morphology. Bone Joint Res 2016;5:387–392. DOI: 10.1302/2046-3758.59.BJR-2016-0028.R1

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Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement.

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Post-traumatic periprosthetic acetabular fractures are rare but serious. Few studies carried out on small cohorts have reported them in the literature. The aim of this work is to describe the specific characteristics of post-traumatic periprosthetic acetabular fractures, and the outcome of their surgical treatment in terms of function and complications.

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The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term analysis examines the distal and modular failure patterns of the Prevision hip stem from 18 years of clinical use. A design improvement of the modular taper was introduced in 2008, and the data could also be used to compare the original and the current design of the modular connection.

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The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy.

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The aims of the study were to report for a cohort aged younger than 40 years: 1) indications for HRA; 2) patient-reported outcomes in terms of the modified Harris Hip Score (HHS); 3) dislocation rate; and 4) revision rate.

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Pelvic discontinuity is a rare but increasingly common complication of total hip arthroplasty (THA). This single-centre study evaluated the performance of custom-made triflange acetabular components in acetabular reconstruction with pelvic discontinuity by determining: 1) revision and overall implant survival rates; 2) discontinuity healing rate; and 3) Harris Hip Score (HHS).

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Cemented hemiarthroplasty is an effective form of treatment for most patients with an intracapsular fracture of the hip. However, it remains unclear whether there are subgroups of patients who may benefit from the alternative operation of a modern uncemented hemiarthroplasty – the aim of this study was to investigate this issue. Knowledge about the heterogeneity of treatment effects is important for surgeons in order to target operations towards specific subgroups who would benefit the most.

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Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model.