Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

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In computer simulations, the shape of the range of motion (ROM) of a stem with a cylindrical neck design will be a perfect cone. However, many modern stems have rectangular/oval-shaped necks. We hypothesized that the rectangular/oval stem neck will affect the shape of the ROM and the prosthetic impingement.

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This study assessed the impact of COVID-19 on hip and distal femur fracture patient outcomes across three successive UK lockdown periods over one year.

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Nearly 99,000 total knee arthroplasties (TKAs) are performed in UK annually. Despite plenty of research, the satisfaction rate of this surgery is around 80%. One of the important intraoperative factors affecting the outcome is alignment. The relationship between joint obliquity and functional outcomes is not well understood. Therefore, a study is required to investigate and compare the effects of two types of alignment (mechanical and kinematic) on functional outcomes and range of motion.

Restoration of leg length and offset is an important goal in total hip replacement. This paper reports a calliper-based technique to help achieve these goals by restoring the location of the centre of the femoral head. This was validated first by using a co-ordinate measuring machine to see how closely the calliper technique could record and restore the centre of the femoral head when simulating hip replacement on Sawbone femur, and secondly by using CT in patients undergoing hip replacement. Results from the co-ordinate measuring machine showed that the centre of the femoral head was predicted by the calliper to within 4.3 mm for offset (mean 1.6 (95% confidence interval (CI) 0.4 to 2.8)) and 2.4 mm for vertical height (mean -0.6 (95% CI -1.4 to 0.2)). The CT scans showed that offset and vertical height were restored to within 8 mm (mean -1 (95% CI -2.1 to 0.6)) and -14 mm (mean 4 (95% CI 1.8 to 4.3)), respectively. Accurate assessment and restoration of the centre of the femoral head is feasible with a calliper. It is quick, inexpensive, simple to use and can be applied to any design of femoral component

We reviewed seven children with torticollis due to refractory atlanto-axial rotatory fixation who were treated in a halo vest. Pre-operative three-dimensional CT and sagittal CT imaging showed deformity of the superior articular process of C2 in all patients. The mean duration of halo vest treatment was 67 days (46 to 91). The mean follow-up was 34 months (8 to 73); at the latest review six patients demonstrated remodelling of the deformed articular process. The other child, who had a more severe deformity, required C1-2 fusion. We suggest that patients with atlanto-axial rotatory fixation who do not respond to conservative treatment and who have deformity of the superior articular process of C2 should undergo manipulative reduction and halo-vest fixation for two to three months to induce remodelling of the deformed superior articular process before C1-2 fusion is considered

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It is unclear whether acute plate fixation facilitates earlier return of normal shoulder function following a displaced mid-shaft clavicular fracture compared with nonoperative management when union occurs. The primary aim of this study was to establish whether acute plate fixation was associated with a greater return of normal shoulder function when compared with nonoperative management in patients who unite their fractures. The secondary aim was to investigate whether there were identifiable predictors associated with return of normal shoulder function in patients who achieve union with nonoperative management.

CT and advanced computer-aided design techniques offer the means for designing customised femoral stems. Our aim was to determine the Hounsfield (HU) value of the bone at the corticocancellous interface, as part of the criteria for the design algorithm. We obtained transverse CT images from eight human cadaver femora. The proximal femoral canal was rasped until contact with dense cortical bone was achieved. The femora were cut into several sections corresponding to the slice positions of the CT images. After obtaining a computerised image of the anatomical sections using a scanner, the inner cortical contour was outlined and transferred to the corresponding CT image. The pixels beneath this contour represent the CT density of the bone remaining after surgical rasping. Contours were generated automatically at nine HU levels from 300 to 1100 and the mean distance between the transferred contour and each of the HU-generated contours was computed. The contour generated along the 600-HU pixels was closest to the inner cortical contour of the rasped femur and therefore 600 HU seem to be the CT density of the corticocancellous interface in the proximal part of cadaver femora. Generally, femoral bone with a CT density beyond 600 HU is not removable by conventional reamers. Thus, we recommend the 600 HU threshold as one of several criteria for the design of custom femoral implants from CT data

Aims. We aimed to investigate factors related to the technique of medial opening wedge high tibial osteotomy which might predispose to the development of a lateral hinge fracture. Patients and Methods. A total of 71 patients with 82 osteotomies were included in the study. Their mean age was 62.9 years (37 to 80). The classification of the type of osteotomy was based on whether it extended beyond the fibular head. The level of the osteotomy was classified according to the height of its endpoint. Results. At a mean follow-up of 20 months (6 to 52), a total of 15 lateral hinge fractures (18.3%) were identified. A sufficient osteotomy, in which both anterior and posterior tibial cortices were involved with extension into the lateral aspect of the plateau in relation to an anteroposterior line tangential to the medial edge of the fibular head in the CT axial plane, was seen in 48 knees (71.6%) in those without a lateral hinge fracture and in seven (46.7%) in those with a lateral hinge fracture. An osteotomy which ended above the level of the fibular head was seen in nine (13.4%) of the knees without a lateral hinge fracture and seven (46.7%) of the those with a lateral hinge fracture. There was a significant relationship between the absence of a lateral hinge fracture and both a sufficient osteotomy and one whose endpoint was at the level of the fibular head (p = 0.0451 and p = 0.0214, respectively). Conclusion. A sufficient osteotomy involving both the anterior and posterior cortices, whose endpoint is at the level of the fibular head, should be performed when undertaking a medial opening wedge high tibial osteotomy if a lateral hinge fracture is to be avoided as a complication. Cite this article: Bone Joint J 2017;99-B:887–93

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To fully verify the reliability and reproducibility of an experimental method in generating standardized micromotion for the rat femur fracture model.

In an interdisciplinary project involving electronic engineers and clinicians, a telemetric system was developed to measure the bending load in a titanium internal femoral fixator. As this was a new device, the main question posed was: what clinically relevant information could be drawn from its application? As a first clinical investigation, 27 patients (24 men, three women) with a mean age of 38.4 years (19 to 66) with femoral nonunions were treated using the system. The mean duration of the nonunion was 15.4 months (5 to 69). The elasticity of the plate-callus system was measured telemetrically until union. Conventional radiographs and a CT scan at 12 weeks were performed routinely, and healing was staged according to the CT scans. All nonunions healed at a mean of 21.5 weeks (13 to 37). Well before any radiological signs of healing could be detected, a substantial decrease in elasticity was recorded. The relative elasticity decreased to 50% at a mean of 7.8 weeks (3.5 to 13) and to 10% at a mean of 19.3 weeks (4.5 to 37). At 12 weeks the mean relative elasticity was 28.1% (0% to 56%). The relative elasticity was significantly different between the different healing stages as determined by the CT scans. Incorporating load measuring electronics into implants is a promising option for the assessment of bone healing. Future application might lead to a reduction in the need for exposure to ionising radiation to monitor fracture healing

The purpose of this study was to determine whether it would be feasible to use oblique lumbar interbody fixation for patients with degenerative lumbar disease who required a fusion but did not have a spondylolisthesis. A series of CT digital images from 60 patients with abdominal disease were reconstructed in three dimensions (3D) using Mimics v10.01: a digital cylinder was superimposed on the reconstructed image to simulate the position of an interbody screw. The optimal entry point of the screw and measurements of its trajectory were recorded. Next, 26 cadaveric specimens were subjected to oblique lumbar interbody fixation on the basis of the measurements derived from the imaging studies. These were then compared with measurements derived directly from the cadaveric vertebrae. Our study suggested that it is easy to insert the screws for L1/2, L2/3 and L3/4 fixation: there was no significant difference in measurements between those of the 3-D digital images and the cadaveric specimens. For L4/5 fixation, part of L5 inferior articular process had to be removed to achieve the optimal trajectory of the screw. For L5/S1 fixation, the screw heads were blocked by iliac bone: consequently, the interior oblique angle of the cadaveric specimens was less than that seen in the 3D digital images. . We suggest that CT scans should be carried out pre-operatively if this procedure is to be adopted in clinical practice. This will assist in determining the feasibility of the procedure and will provide accurate information to assist introduction of the screws. Cite this article: Bone Joint J 2013;95-B:977–82

Aims. The purpose of this study was to determine if clinical and radiological surveillance of cartilage tumours with low biological activity is appropriate. Patients and Methods. A total of 98 patients with an intramedullary cartilage neoplasm in a long bone met our inclusion criteria and were included in the study. These patients had undergone a total of 384 scans. Patients with radiological follow-up of more than three years (46 patients) were divided into two groups: an active group (11 patients) and a latent group (35 patients). Results. Active lesions had a total growth in all three planes that was > 6 mm, whilst latent lesions had < 6 mm of growth. Most latent lesions were heavily calcified: active lesions were calcified less than 50% (p = 0.025). Conclusion. Clinico-radiological surveillance can identify growing cartilage lesions: MRI is the surveillance modality of choice. A CT scan is recommended, in addition, at presentation to assess the amount of calcification within the lesion. A first follow-up MRI is suggested one year from diagnosis. If the total growth in the cartilage lesion is > 6 mm, surgical treatment should be considered. Otherwise, a second surveillance scan can be performed at three years to determine further management. Cite this article: Bone Joint J 2016;98-B:1542–7

We measured the orientation of the acetabular and femoral components in 45 patients (33 men, 12 women) with a mean age of 53.4 years (30 to 74) who had undergone revision of metal-on-metal hip resurfacings. Three-dimensional CT was used to measure the inclination and version of the acetabular component, femoral version and the horizontal femoral offset, and the linear wear of the removed acetabular components was measured using a roundness machine. We found that acetabular version and combined version of the acetabular and femoral components were weakly positively correlated with the rate of wear. The acetabular inclination angle was strongly positively correlated with the rate of wear. Femoral version was weakly negatively correlated with the rate of wear. Application of a threshold of > 5 μm/year for the rate of wear in order to separate the revisions into low or high wearing groups showed that more high wearing components were implanted outside Lewinnek’s safe zone, but that this was mainly due to the inclination of the acetabular component, which was the only parameter that significantly differed between the groups. We were unable to show that excess version of the acetabular component alone or combined with femoral version was associated with an increase in the rate of wear based on our assessment of version using CT

Aims. Restoring the pre-morbid anatomy of the proximal humerus is a goal of anatomical shoulder arthroplasty, but reliance is placed on the surgeon’s experience and on anatomical estimations. The purpose of this study was to present a novel method, ‘Statistical Shape Modelling’, which accurately predicts the pre-morbid proximal humeral anatomy and calculates the 3D geometric parameters needed to restore normal anatomy in patients with severe degenerative osteoarthritis or a fracture of the proximal humerus. Materials and Methods. From a database of 57 humeral CT scans 3D humeral reconstructions were manually created. The reconstructions were used to construct a statistical shape model (SSM), which was then tested on a second set of 52 scans. For each humerus in the second set, 3D reconstructions of four diaphyseal segments of varying lengths were created. These reconstructions were chosen to mimic severe osteoarthritis, a fracture of the surgical neck of the humerus and a proximal humeral fracture with diaphyseal extension. The SSM was then applied to the diaphyseal segments to see how well it predicted proximal morphology, using the actual proximal humeral morphology for comparison. Results. With the metaphysis included, mimicking osteoarthritis, the errors of prediction for retroversion, inclination, height, radius of curvature and posterior and medial offset of the head of the humerus were 2.9° (± 2.3°), 4.0° (± 3.3°), 1.0 mm (± 0.8 mm), 0.8 mm (± 0.6 mm), 0.7 mm (± 0.5 mm) and 1.0 mm (± 0.7 mm), respectively. With the metaphysis excluded, mimicking a fracture of the surgical neck, the errors of prediction for retroversion, inclination, height, radius of curvature and posterior and medial offset of the head of the humerus were 3.8° (± 2.9°), 3.9° (± 3.4°), 2.4 mm (± 1.9 mm), 1.3 mm (± 0.9 mm), 0.8 mm (± 0.5 mm) and 0.9 mm (± 0.6 mm), respectively. Conclusion. This study reports a novel, computerised method that accurately predicts the pre-morbid proximal humeral anatomy even in challenging situations. This information can be used in the surgical planning and operative reconstruction of patients with severe degenerative osteoarthritis or with a fracture of the proximal humerus. Cite this article: Bone Joint J 2017;99-B:927–33

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To determine the role of early MRI in the management of suspected scaphoid fractures.

Aims. Accurate placement of the acetabular component during total hip arthroplasty (THA) is an important factor in the success of the procedure. However, the reported accuracy varies greatly and is dependent upon whether free hand or navigated techniques are used. The aim of this study was to assess the accuracy of an instrument system that incorporates 3D printed, patient-specific guides designed to optimise the placement of the acetabular component. Patients and Methods. A total of 100 consecutive patients were prospectively enrolled and the accuracy of placement of the acetabular component was measured using post-operative CT scans. Results. The mean absolute deviation from the planned inclination and anteversion was 3.9° (0.0° to 13.6°) and 3.6° (0.0° to 12.9°), respectively. In 91% of cases the planned target of +/-10° was achieved for both inclination and anteversion. Conclusion. Accurate placement of the acetabular component can be achieved using patient-specific guides and is superior to free hand techniques and comparable to navigated and robotic techniques. Cite this article: Bone Joint J 2016;98-B:1342–6

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To determine the likelihood of achieving a successful closed reduction (CR) of a dislocated hip in developmental dysplasia of the hip (DDH) after failed Pavlik harness treatment We report the rate of avascular necrosis (AVN) and the need for further surgical procedures.