Aims. Traditionally, total hip arthroplasty (THA) templating has been performed on anteroposterior (AP) pelvis radiographs. Recently, additional AP hip radiographs have been recommended for accurate measurement of the femoral offset (FO). To verify this claim, this study aimed to establish quantitative data of the measurement error of the FO in relation to leg position and X-ray source position using a newly developed geometric model and clinical data. Methods. We analyzed the FOs measured on AP hip and pelvis radiographs in a prospective consecutive series of 55 patients undergoing unilateral primary THA for hip osteoarthritis. To determine sample size, a power analysis was performed. Patients’ position and X-ray beam setting followed a standardized protocol to achieve reproducible projections. All images were calibrated with the KingMark calibration system. In addition, a geometric model was created to evaluate both the effects of leg position (rotation and
Aims. After failed acetabular fractures, total hip arthroplasty (THA) is a challenging procedure and considered the gold standard treatment. The complexity of the procedure depends on the fracture pattern and the initial fracture management. This study’s primary aim was to evaluate patient-reported outcome measures (PROMs) for patients who underwent delayed uncemented acetabular THA after acetabular fractures. The secondary aims were to assess the radiological outcome and the incidence of the associated complications in those patients. Methods. A total of 40 patients underwent cementless acetabular THA following failed treatment of acetabular fractures. The postoperative clinical and radiological outcomes were evaluated for all the cohort. Results. The median (interquartile range (IQR)) Oxford Hip Score (OHS) improved significantly from 9.5 (7 to 11.5), (95% confidence interval (CI) (8 to 10.6)) to 40 (39 to 44), (95% CI (40 to 43)) postoperatively at the latest follow-up (p < 0.001). It was worth noting that the initial acetabular fracture type (simple vs complex), previous acetabular treatment (ORIF vs conservative), fracture union, and restoration of anatomical centre of rotation (COR) did not affect the final OHS. The reconstructed centre of rotation (COR) was restored in 29 (72.5%) patients. The mean
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
Aims. 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. Methods. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records. Results. A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4°
Avascular femoral head necrosis in the context of gymnastics is a rare but serious complication, appearing similar to Perthes’ disease but occurring later during adolescence. Based on 3D CT animations, we propose repetitive impact between the main supplying vessels on the posterolateral femoral neck and the posterior acetabular wall in hyperextension and external rotation as a possible cause of direct vascular damage, and subsequent femoral head necrosis in three adolescent female gymnasts we are reporting on. Outcome of hip-preserving head reduction osteotomy combined with periacetabular osteotomy was good in one and moderate in the other up to three years after surgery; based on the pronounced hip destruction, the third received initially a total hip arthroplasty.Aims
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This study aimed to develop and validate a fully automated system that quantifies proximal femoral bone mineral density (BMD) from CT images. The study analyzed 978 pairs of hip CT and dual-energy X-ray absorptiometry (DXA) measurements of the proximal femur (DXA-BMD) collected from three institutions. From the CT images, the femur and a calibration phantom were automatically segmented using previously trained deep-learning models. The Hounsfield units of each voxel were converted into density (mg/cm3). Then, a deep-learning model trained by manual landmark selection of 315 cases was developed to select the landmarks at the proximal femur to rotate the CT volume to the neutral position. Finally, the CT volume of the femur was projected onto the coronal plane, and the areal BMD of the proximal femur (CT-aBMD) was quantified. CT-aBMD correlated to DXA-BMD, and a receiver operating characteristic (ROC) analysis quantified the accuracy in diagnosing osteoporosis.Aims
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Eccentric reductions may become concentric through femoral head ‘docking’ (FHD) following closed reduction (CR) for developmental dysplasia of the hip (DDH). However, changes regarding position and morphology through FHD are not well understood. We aimed to assess these changes using serial MRI. We reviewed 103 patients with DDH successfully treated by CR and spica casting in a single institution between January 2016 and December 2020. MRI was routinely performed immediately after CR and at the end of each cast. Using MRI, we described the labrum-acetabular cartilage complex (LACC) morphology, and measured the femoral head to triradiate cartilage distance (FTD) on the midcoronal section. A total of 13 hips with initial complete reduction (i.e. FTD < 1 mm) and ten hips with incomplete MRI follow-up were excluded. A total of 86 patients (92 hips) with a FTD > 1 mm were included in the analysis.Aims
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Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures.Aims
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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. This international, multicentre prospective cohort study across two centres encompassed 157 adults undergoing primary robotic arm-assisted THA. Impingement during specific flexion and extension stances was identified using the virtual range of motion (ROM) tool of the robotic software. The primary AI model, the Light Gradient-Boosting Machine (LGBM), used tabular data to predict impingement presence, direction (flexion or extension), and type. A secondary model integrating tabular data with plain anteroposterior pelvis radiographs was evaluated to assess for any potential enhancement in prediction accuracy.Aims
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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). Retrospectively collected data of 38 patients (39 hips) with pelvic discontinuity treated with revision THA using a custom-made triflange acetabular component were analyzed. Minimum follow-up was two years (mean 5.1 years (2 to 11)).Aims
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Developmental dysplasia of the hip (DDH) describes a pathological relationship between the femoral head and acetabulum. Periacetabular osteotomy (PAO) may be used to treat this condition. The aim of this study was to evaluate the results of PAO in adolescents and adults with persistent DDH. Patients were divided into four groups: A, adolescents who had not undergone surgery for DDH in childhood (25 hips); B, adolescents who had undergone surgery for DDH in childhood (20 hips); C, adults with DDH who had not undergone previous surgery (80 hips); and D, a control group of patients with healthy hips (70 hips). The radiological evaluation of digital anteroposterior views of hips included the Wiberg angle (centre-edge angle (CEA)), femoral head cover (FHC), medialization, distalization, and the ilioischial angle. Clinical assessment involved the Harris Hip Score (HHS) and gluteal muscle performance assessment.Aims
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The localization of necrotic areas has been reported to impact the prognosis and treatment strategy for osteonecrosis of the femoral head (ONFH). Anteroposterior localization of the necrotic area after a femoral neck fracture (FNF) has not been properly investigated. We hypothesize that the change of the weight loading direction on the femoral head due to residual posterior tilt caused by malunited FNF may affect the location of ONFH. We investigate the relationship between the posterior tilt angle (PTA) and anteroposterior localization of osteonecrosis using lateral hip radiographs. Patients aged younger than 55 years diagnosed with ONFH after FNF were retrospectively reviewed. Overall, 65 hips (38 males and 27 females; mean age 32.6 years (SD 12.2)) met the inclusion criteria. Patients with stage 1 or 4 ONFH, as per the Association Research Circulation Osseous classification, were excluded. The ratios of anterior and posterior viable areas and necrotic areas of the femoral head to the articular surface were calculated by setting the femoral head centre as the reference point. The PTA was measured using Palm’s method. The association between the PTA and viable or necrotic areas of the femoral head was assessed using Spearman’s rank correlation analysis (median PTA 6.0° (interquartile range 3 to 11.5)).Aims
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The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS. A retrospective analysis of all revision hip procedures was performed at this centre over two consecutive financial years (2018 to 2020). Cases were classified according to the Revision Hip Complexity Classification (RHCC) and whether they were infected or non-infected. Patients with an American Society of Anesthesiologists (ASA) grade ≥ III or BMI ≥ 40 kg/m2 are considered “high risk” by the RHCC. Costs were calculated using the Patient Level Information and Costing System (PLICS), and remuneration based on Healthcare Resource Groups (HRG) data. The primary outcome was the financial difference between tariff and cost per patient episode.Aims
Methods
Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements.Aims
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The aim of this modified Delphi process was to create a structured Revision Hip Complexity Classification (RHCC) which can be used as a tool to help direct multidisciplinary team (MDT) discussions of complex cases in local or regional revision networks. The RHCC was developed with the help of a steering group and an invitation through the British Hip Society (BHS) to members to apply, forming an expert panel of 35. We ran a mixed-method modified Delphi process (three rounds of questionnaires and one virtual meeting). Round 1 consisted of identifying the factors that govern the decision-making and complexities, with weighting given to factors considered most important by experts. Participants were asked to identify classification systems where relevant. Rounds 2 and 3 focused on grouping each factor into H1, H2, or H3, creating a hierarchy of complexity. This was followed by a virtual meeting in an attempt to achieve consensus on the factors which had not achieved consensus in preceding rounds.Aims
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The aim of this study was to assess the clinical and radiological results of patients who were revised using a custom-made triflange acetabular component (CTAC) for component loosening and pelvic discontinuity (PD) after previous total hip arthroplasty (THA). Data were extracted from a single centre prospective database of patients with PD who were treated with a CTAC. Patients were included if they had a follow-up of two years. The Hip Disability and Osteoarthritis Outcome Score (HOOS), modified Oxford Hip Score (mOHS), EurQol EuroQoL five-dimension three-level (EQ-5D-3L) utility, and Numeric Rating Scale (NRS), including visual analogue score (VAS) for pain, were gathered at baseline, and at one- and two-year follow-up. Reasons for revision, and radiological and clinical complications were registered. Trends over time are described and tested for significance and clinical relevance.Aims
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In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component. Between 2012 and 2020, across two centres, 94 patients underwent revision of Birmingham MoM hip arthroplasties or resurfacings. Mean age was 65.5 years (33 to 87). In 53 patients (56.4%), the acetabular component was retained and dual-mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). Patients underwent follow-up of minimum two-years (mean 4.6 (2.1 to 8.5) years).Aims
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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. A model of a THA was developed using a 20° lipped liner. Kinematic analyses included a physiological range of motion (ROM) analysis and a provocative dislocation manoeuvre analysis. ROM prior to impingement was calculated and, in impingement scenarios, the travel distance prior to dislocation was assessed. The combinations analyzed included nine cup positions (inclination 30-40-50°, anteversion 5-15-25°), three stem positions (anteversion 0-15-30°), and five lip orientations (right hip 7 to 11 o’clock).Aims
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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. Between November 2000 and December 2016, we retrospectively evaluated 144 consecutive hip procedures in 122 patients a minimum of five years after undergoing modified Spitzy shelf acetabuloplasty for acetabular dysplasia including osteoarthritis (OA). Our follow-up rate was 92%. The mean age at time of surgery was 37 years (13 to 58), with a mean follow-up of 11 years (5 to 21). Advanced OA (Tönnis grade ≥ 2) was present preoperatively in 16 hips (11%). The preoperative lateral centre-edge angle ranged from -28° to 25°. Survival was determined by Kaplan-Meier analysis, using conversions to total hip arthroplasty as the endpoint. Risk factors for joint space narrowing less than 2 mm were analyzed using a Cox proportional hazards model.Aims
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Perthes’ disease is an uncommon hip disorder with limited data on the long-term outcomes in adulthood. We partnered with community-based foundations and utilized web-based survey methodology to develop the Adult Perthes Survey, which includes demographics, childhood and adult Perthes’ disease history, the University of California Los Angeles (UCLA) Activity Scale item, Short Form-36, the Hip disability and Osteoarthritis Outcome Score, and a body pain diagram. Here we investigate the following questions: 1) what is the feasibility of obtaining > 1,000 survey responses from adults who had Perthes’ disease using a web-based platform?; and 2) what are the baseline characteristics and demographic composition of our sample? The survey link was available publicly for 15 months and advertised among support groups. Of 1,505 participants who attempted the Adult Perthes survey, 1,182 completed it with a median timeframe of 11 minutes (IQR 8.633 to 14.72). Participants who dropped out were similar to those who completed the survey on several fixed variables. Participants represented 45 countries including the USA (n = 570; 48%), UK (n = 295; 25%), Australia (n = 133; 11%), and Canada (n = 46; 4%). Of the 1,182 respondents, 58% were female and the mean age was 39 years (SD 12.6).Aims
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