Aims. One goal of total hip arthroplasty is to restore normal hip anatomy. The aim of this study was to compare displacement of the centre of rotation (COR) using a standard reaming technique with a technique in which the acetabulum was reamed immediately peripherally and referenced off the rim. Patients and Methods. In the first cohort the acetabulum was reamed to the floor followed by sequentially larger reamers. In the second cohort the acetabulum was only reamed peripherally, starting with a reamer the same size as the native femoral head. Anteroposterior pelvic radiographs were analysed for acetabular floor depth and vertical and horizontal position of the COR. Results. Horizontally, the mean medial displacement of the COR was 0.8 mm (standard deviation (. sd. ) 1.4) in the peripheral remaing group and 5.0 mm (. sd. 3.30) in the standard reaming group (p < 0.001). Vertically, the mean superior displacement of the COR was 0.7 mm (. sd. 1.3) in the peripheral reaming group and 3.7 mm (. sd. 2.6) in the standard reaming group (p <  0.001). In the standard reaming group, there was a strong correlation between the pre-operative acetabular floor depth and displacement of the COR (p < 0.001). Conclusion. Reaming the acetabulum to the floor can lead to significant displacement of the COR medially and superiorly. This displacement is related to the pre-operative acetabular floor depth and cannot always be compensated by using a high offset stem. Cite this article: Bone Joint J 2016;98-B:1597–603

In this study we used subject-specific finite element analysis to investigate the mechanical effects of rotational acetabular osteotomy (RAO) on the hip joint and analysed the correlation between various radiological measurements and mechanical stress in the hip joint. We evaluated 13 hips in 12 patients (two men and ten women, mean age at surgery 32.0 years; 19 to 46) with developmental dysplasia of the hip (DDH) who were treated by RAO. Subject-specific finite element models were constructed from CT data. The centre–edge (CE) angle, acetabular head index (AHI), acetabular angle and acetabular roof angle (ARA) were measured on anteroposterior pelvic radiographs taken before and after RAO. The relationship between equivalent stress in the hip joint and radiological measurements was analysed. The equivalent stress in the acetabulum decreased from 4.1 MPa (2.7 to 6.5) pre-operatively to 2.8 MPa (1.8 to 3.6) post-operatively (p < 0.01). There was a moderate correlation between equivalent stress in the acetabulum and the radiological measurements: CE angle (R = –0.645, p < 0.01); AHI (R = –0.603, p < 0.01); acetabular angle (R = 0.484, p = 0.02); and ARA (R = 0.572, p < 0.01). The equivalent stress in the acetabulum of patients with DDH decreased after RAO. Correction of the CE angle, AHI and ARA was considered to be important in reducing the mechanical stress in the hip joint. Cite this article: Bone Joint J 2015;97-B:492–7

Three-dimensional surface models of the normal hemipelvis derived from volumetric CT data on 42 patients were used to determine the radius, depth and orientation of the native acetabulum. A sphere fitted to the lunate surface and a plane matched to the acetabular rim were used to calculate the radius, depth and anatomical orientation of the acetabulum. For the 22 females the mean acetabular abduction, anteversion, radius and normalised depth were 57.1° (50.7° to 66.8°), 24.1° (14.0° to 33.3°), 25 mm (21.7 to 30.3) and 0.79 mm (0.56 to 1.04), respectively. The same parameters for the 20 males were 55.5° (47.7° to 65.9°), 19.3° (8.5° to 32.3°), 26.7 mm (24.5 to 28.7) and 0.85 mm (0.65 to 0.99), respectively. The orientation of the native acetabulum did not match the safe zone for acetabular component placement described by Lewinnek. During total hip replacement surgeons should be aware that the average abduction angle of the native acetabulum exceeds that of the safe zone angle. If the concept of the safe zone angle is followed, abduction of the acetabular component should be less than the abduction of the native acetabulum by approximately 10°

Aims. The goal of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) is to achieve and maintain concentricity of the femoral head in the acetabulum. However, concentric reduction is not immediately attainable in all hips and it remains controversial to what degree a non-concentric reduction is acceptable. This prospective study is aimed at investigating the dynamic evolution of the hip joint space after CR in DDH using MRI. Methods. A consecutive series of patients with DDH who underwent CR since March 2014 were studied. Once the safety and stability were deemed adequate intraoperatively, reduction was accepted regardless of concentricity. Concentricity was defined when the superior joint space (SJS) and medial joint space (MJS) were both less than 2 mm, based on MRI. A total of 30 children, six boys and 24 girls, involving 35 hips, were recruited for the study. The mean age at CR was 13.7 months (3.5 to 27.6) and the mean follow-up was 49.5 months (approximately four years) (37 to 60). The joint space was evaluated along with the interval between the inverted and everted limbus. Results. Only three hips (8.6%) were fully concentric immediately after CR. During follow-up, 24 hips (68.6%) and 27 hips (77.1%) became concentric at six months and one year, respectively. Immediate SJS after CR decreased from 3.51 mm to 0.79 mm at six months follow-up (p = 0.001). SJS in the inverted group decreased from 3.75 mm to 0.97 mm at six months follow-up. SJS or MJS in the everted group were less than those in the inverted group at each time of follow-up (p = 0.008, p = 0.002). Conclusion. A stable, safe but non-concentric reduction achieved before the age of two years appears to improve over time with nearly 80% of hips becoming fully concentric by one year. Cite this article: Bone Joint J 2020;102-B(5):618–626

Aims. Dislocation rates are reportedly lower in patients requiring proximal femoral hemiarthroplasty than for patients undergoing hip arthroplasty for neoplasia. Without acetabular replacement, pain due to acetabular wear necessitating revision surgery has been described. We aimed to determine whether wear of the native acetabulum following hemiarthroplasty necessitates revision surgery with secondary replacement of the acetabulum after proximal femoral replacement (PFR) for tumour reconstruction. Patients and Methods. We reviewed 100 consecutive PFRs performed between January 2003 and January 2013 without acetabular resurfacing. The procedure was undertaken in 74 patients with metastases, for a primary bone tumour in 20 and for myeloma in six. There were 48 male and 52 female patients, with a mean age of 61.4 years (19 to 85) and median follow-up of two years (interquartile range (IQR) 0.5 to 3.7 years). In total, 52 patients presented with a pathological fracture and six presented with failed fixation of a previously instrumented pathological fracture. Results. All patients underwent reconstruction with either a unipolar (n = 64) or bipolar (n = 36) articulation. There were no dislocations and no acetabular resurfacings. Articular wear was graded using the criteria of Baker et al from 0 to 3, where by 0 is normal; grade 1 represents a narrowing of articular cartilage and no bone erosion; grade 2 represents acetabular bone erosion and early migration; and grade 3 represents protrusio acetabuli. Of the 49 patients with radiological follow-up greater than one year, six demonstrated grade 1 acetabular wear and two demonstrated grade 2 acetabular wear. The remainder demonstrated no radiographic evidence of wear. Median medial migration was 0.3 mm (IQR -0.2 to 0.7) and superior migration was 0.3 mm (IQR -0.2 to 0.6). No relationship between unipolar versus bipolar articulations and wear was evident. Conclusion. Hemiarthroplasty PFRs for tumour reconstruction eliminate joint instability and, in the short to medium term, do not lead to native acetabular wear necessitating later acetabular resurfacing. Cite this article: Bone Joint J 2018;100B:101–8

Aims

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.

Aims. We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component, as assessed by morphometric geometrical analysis, and its reliability. Patients and Methods. A total of 52 Crowe IV hips (42 patients; seven male, 35 female; mean age 68.5 years (32 to 82)) and 50 normal hips (50 patients; eight male, 42 female; mean age 60.7 years (34 to 86)) undergoing total hip arthroplasty were retrospectively identified. In this CT-based simulation study, the acetabular component was positioned at the true acetabulum with a radiological inclination of 40° and anteversion of 20°. Acetabular shape and the position of the centre of the acetabular component were analyzed by morphometric geometrical analysis using the generalized Procrustes analysis. Results. The acetabular shapes of Crowe IV hips were distinctively triangular; the ideal position of the centre of the acetabular component was superior on the posterior bony wall. The first and second relative warps explained 34.2% and 18.4% of the variance, respectively, compared with that of 28.6% and 18.0% in normal hips. We defined the landmark as one-third the distance from top on the posterior bony wall in Crowe IV hips. The average distance from the centre of the acetabular component was 5.6 mm. Conclusion. Crowe IV hips are distinctively triangular; the point one-third from the top on the posterior bony wall was a useful landmark for placing the acetabular component

Aims

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.

Aims

Pelvic discontinuity is a challenging acetabular defect without a consensus on surgical management. Cup-cage reconstruction is an increasingly used treatment strategy. The present study evaluated implant survival, clinical and radiological outcomes, and complications associated with the cup-cage construct.

Resurfacing arthroplasty of the hip is being performed more frequently in the United Kingdom. The majority of these patients are younger than 55 years of age, and in this group the key benefits include conservation of femoral bone stock and the potential reduction in the rate of dislocation afforded by the larger resurfacing head. Early aseptic loosening is well recognised in patients younger than 55 years of age, and proponents of resurfacing believe that the improved wear characteristics of the metal-on-metal bearing may improve the long-term survival of this implant. There has been some concern, however, that resurfacing may not be conservative of acetabular bone. We compared a series of 33 consecutive patients who had a hybrid total hip arthroplasty with an uncemented acetabular component and a cemented femoral implant, with 35 patients undergoing a Birmingham hip resurfacing arthroplasty. We compared the diameter of the implanted acetabulum in both groups and, because they were not directly comparable, we corrected for patient size by measuring the diameter of the contralateral femoral head. The data were analysed using unpaired t-tests and analysis of covariance. There was a significantly larger acetabulum in the Birmingham arthroplasty group (mean diameter 56.6 mm vs 52.0 mm; p < 0.001). However, this group had a significantly larger femoral head diameter on the contralateral side (p = 0.03). Analysis of covariance revealed a significant difference between the mean size of the acetabular component implanted in the two operations. The greatest difference in the size of acetabulum was in those patients with a larger diameter of the femoral head. This study shows that more bone is removed from the acetabulum in hip resurfacing than during hybrid total hip arthroplasty, a difference which is most marked in larger patients

This paper describes the technique and results of an acetabuloplasty in which the false acetabulum is turned down to augment the dysplastic true acetabulum at its most defective part. This operation was performed in 17 hips (16 children), with congenital dislocation and false acetabula. The mean age at operation was 5.1 years (4 to 8). The patients were followed clinically and radiologically for a mean of 6.3 years (5 to 10). A total of 16 hips had excellent results and there was one fair result due to avascular necrosis. The centre-edge angles and the obliquity of the acetabular roof improved in all cases, from a mean of −15.9° (−19° to 3°) and 42.6° (33° to 46°) to a mean of 29.5° (20° to 34°) and 11.9° (9° to 19°), respectively. The technique is not complex and is stable without internal fixation. It provides a near-normal acetabulum that requires minimal remodelling, and allows early mobilisation

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The aim of this study was to explore differences in operative autonomy by trainee gender during orthopaedic training in Ireland and the UK, and to explore differences in operative autonomy by trainee gender with regard to training year, case complexity, index procedures, and speciality area.

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Mechanical impingement of the iliopsoas (IP) tendon accounts for 2% to 6% of persistent postoperative pain after total hip arthroplasty (THA). The most common initiator is anterior acetabular component protrusion, where the anterior margin is not covered by anterior acetabular wall. A CT scan can be used to identify and measure this overhang; however, no threshold exists for determining symptomatic anterior IP impingement due to overhang. A case-control study was conducted in which CT scan measurements were used to define a threshold that differentiates patients with IP impingement from asymptomatic patients after THA.

The February 2023 Trauma Roundup³⁶⁰ looks at: Masquelet versus bone transport in infected nonunion of tibia; Hyperbaric Oxygen for Lower Limb Trauma (HOLLT): an international multicentre randomized clinical trial; Is the T-shaped acetabular fracture really a “T”?; What causes cut-out of proximal femur nail anti-rotation device in intertrochanteric fractures?; Is the common femoral artery at risk with percutaneous fragility pelvis fixation?; Anterior pelvic ring pattern predicts displacement in lateral compression fractures; Differences in age-related characteristics among elderly patients with hip fractures.

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Studies of infant hip development to date have been limited by considering only the changes in appearance of a single ultrasound slice (Graf’s standard plane). We used 3D ultrasound (3DUS) to establish maturation curves of normal infant hip development, quantifying variation by age, sex, side, and anteroposterior location in the hip.

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The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA.

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Ganz’s studies made it possible to address joint deformities on both the femoral and acetabular side brought about by Perthes’ disease. Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency, along with periacetabular osteotomy (PAO), which may enhance coverage and containment. The purpose of this study is to show the clinical and morphological outcomes of the technique and the use of an implemented planning approach.

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Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies.

Aims

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

The February 2023 Children’s orthopaedics Roundup³⁶⁰ looks at: Trends in management of paediatric distal radius buckle fractures; Pelvic osteotomy in patients with previous sacral-alar-iliac fixation; Sacral-alar-iliac fixation in patients with previous pelvic osteotomy; Idiopathic toe walking: an update on natural history, diagnosis, and treatment; A prediction model for treatment decisions in distal radial physeal injuries: a multicentre retrospective study; Angular deformities after percutaneous epiphysiodesis for leg length discrepancy; MRI assessment of anterior coverage is predictive of future radiological coverage; Predictive scoring for recurrent patellar instability after a first-time patellar dislocation.