Aims

Staphylococcus aureus is a major cause of septic arthritis, and in vitro studies suggest α haemolysin (Hla) is responsible for chondrocyte death. We used an in vivo murine joint model to compare inoculation with wild type S. aureus 8325-4 with a Hla-deficient strain DU1090 on chondrocyte viability, tissue histology, and joint biomechanics. The aim was to compare the actions of S. aureus Hla alone with those of the animal’s immune response to infection.

Adolescent idiopathic scoliosis (AIS), defined by an age at presentation of 11 to 18 years, has a prevalence of 0.47% and accounts for approximately 90% of all cases of idiopathic scoliosis. Despite decades of research, the exact aetiology of AIS remains unknown. It is becoming evident that it is the result of a complex interplay of genetic, internal, and environmental factors. It has been hypothesized that genetic variants act as the initial trigger that allow epigenetic factors to propagate AIS, which could also explain the wide phenotypic variation in the presentation of the disorder. A better understanding of the underlying aetiological mechanisms could help to establish the diagnosis earlier and allow a more accurate prediction of deformity progression. This, in turn, would prompt imaging and therapeutic intervention at the appropriate time, thereby achieving the best clinical outcome for this group of patients.

Cite this article: Bone Joint J 2022;104-B(8):915–921.

Aims

Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA). The gut microbiome is shown to be involved in OA. However, the effect of exercise on gut microbiome in PTOA remains elusive.

We have assessed the effectiveness of reconstruction of the anterior cruciate ligament (ACL) in reducing functional tibial translation (TT). The gait of 11 ACL-deficient patients was studied using Vicon equipment before and after surgery. Measurements of the angle between the patellar tendon and the long axis of the tibia were obtained in order to calculate TT in the sagittal plane relative to the uninjured limb during standing and walking. Before surgery, patients did not show abnormal TT on the injured side, but after surgery significant anterior TT was found in the operated limb for every parameter of gait. Abnormal anterior TT occurring during activity does not seem to be reduced by reconstruction; rather, it increases. It may be that the increased translation results from relaxation of excess contraction of the hamstring muscles, since compensatory muscle activity no longer is required in a reconstructed knee. The reduction of TT may not be an appropriate objective in surgery on the ACL

We have studied the progression of healing in 103 unstable fractures of the tibia. In 76 patients we removed the external fixator once the stiffness had reached 15 Nm/° in the sagittal plane. Deformity at the site of the fracture subsequently occurred in four patients. In a further 27, we measured stiffness in several planes and removed the fixator only when the stiffness reached 15 Nm/° in each. We found that stiffness in two orthogonal planes may differ widely (maximum difference 9.0 Nm/°, mean 4.1 Nm/°). There were no failures in the second group. We advocate that fracture stiffness be measured in two orthogonal planes when assessing tibial healing and suggest that values above 15 Nm/° in two planes give an indication that it is safe to remove the fixator

Aims

A functional anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) has been assumed to be required for patients undergoing unicompartmental knee arthroplasty (UKA). However, this assumption has not been thoroughly tested. Therefore, this study aimed to assess the biomechanical effects exerted by cruciate ligament-deficient knees with medial UKAs regarding different posterior tibial slopes.

We measured fracture stiffness in 212 patients with tibial fractures treated by external fixation. In the first 117 patients (group 1) the decision to remove the fixator and allow independent weight-bearing was made on clinical grounds. In the other 95 patients (group 2) the frames were removed when the fracture stiffness had reached 15 Nm/degree. In group 1 there were eight refractures and in group 2 there was none (p = 0.02, Fisher's exact test). The time to independent weight-bearing was longer in group 1 (median 24 weeks) than in group 2 (21.7 weeks, p = 0.02). The greater precision of our objective measurement was associated with a reduction in refracture rate and in the time taken to achieve independent weight-bearing. We consider that a stiffness of 15 Nm/degree in the sagittal plane provides a useful definition of union of tibial fractures

We report 14 cases of symptomatic ossification of the posterior longitudinal ligament (OPLL) diagnosed in non-oriental men between 1978 and 1985. All 14 patients had incomplete spinal cord syndromes due to OPLL in the cervical spine and had been referred undiagnosed from other institutions. Twelve had severe myelopathy and seven were wheelchair-bound before OPLL was diagnosed, while six patients had had operations elsewhere for their neurological dysfunction. There was a close association between OPLL and diffuse idiopathic skeletal hyperostosis (Forestier's disease) on plain radiographs, seven patients having both disorders. Enhanced CT scans proved to be the best diagnostic method for the localisation of cord compression, and magnetic resonance imaging, used on four recent cases, provided the best visualisation of the extent of involvement in the sagittal plane. We aim to heighten awareness of OPLL in non-orientals, in whom the clinical features, histological characteristics, and radiographic patterns are very similar to those of oriental patients

Twenty-two high-density polyethylene sockets from Charnley low-friction arthroplasties have been studied. Acrylic casts and shadowgraph techniques were used to measure both the real and radiographic rates of wear; these rates showed a significant correlation. In the sagittal plane, nine of the sockets had worn lateral to a line drawn vertically from the centre of curvature of the socket, 12 had worn medial to that line and only one was worn exactly in the line. In the coronal plane, nine sockets had worn in front of a similar vertical line, two behind that line and 11 had worn exactly in the line. Evidence of impingement of the neck of the stem onto the rim of the socket was found in 14 patients; this is considered to be one of the causes of socket loosening. The obvious solution is to reduce the diameter of the neck of the stem from 12.5 mm to 10 mm; provided that it is made of cold-formed, high nitrogen-content stainless steel, this narrower neck is strong enough not to fracture

We have carried out a radiostereometric study of 50 patients (54 knees) with osteoarthritis of the knee who were randomly allocated to receive a cemented or a hydroxyapatite-coated femoral component for total knee replacement. The patients were also stratified to receive one of three types of articulating surface (standard, rotating platform, Freeman-Samuelson (FS)1000) all based on the Freeman-Samuelson design. The tibial components were cemented in all cases. Radiostereometry was performed post-operatively and at 3, 12 and 24 months. The analysis was restricted to rotation of the femoral component over time. After two years, rotation of the femoral components in the transverse, longitudinal and sagittal planes did not differ between the cemented and the hydroxyapatite-coated implants (p = 0.2 to 0.9). In total knee replacements with a rotating platform, the femoral component tended to tilt more posteriorly than in the other two designs, regardless of the choice of fixation (cemented or hydroxyapatite-coated, p = 0.04). The standard version of the femoral component, whether cemented or hydroxyapatite-coated, rotated more into valgus than was observed with the rotating-platform and FS1000 designs (p = 0.005). The increased constraint provided by the FS1000 component did not appear to have any adverse effect on fixation of the femoral component

We report a prospective study of gait and tibial component migration in 45 patients with osteoarthritis treated by total knee arthroplasty (TKA). Migration was measured over two years using roentgen stereophotogrammetry. We used the previously established threshold of 200 μm migration in the second postoperative year to distinguish two groups: a risk group of 15 patients and a stable group of 28 patients. We performed gait analysis before operation and at six months and at two years after TKA. On all three occasions we found significant differences between the two groups in the mean sagittal plane moments of the knee joint. The risk group walked with higher peak flexion moments than the stable group. The two groups were not discriminated by any clinical or radiological criteria or other gait characteristics. The relationship which we have found between gait with increased flexion moments and risk of tibial component loosening warrants further study as regards the aetiology of prosthetic loosening and possible methods of influencing its incidence

A radiological study of 50 patients with thoracic Scheuermann's disease revealed two types of lateral spinal curvature. A total of 43 lateral curves was present in 35 of the patients. Thirteen were apical at the same level as the Scheuermann's kyphosis and were due to vertebral-body wedging in the coronal plane; these curves had a mean Cobb angle of 15 degrees, occurred with equal prevalence in boys and girls and were directed equally to right and left. Thirty curves occurred in regions of compensatory lordosis (mean 5.6 degrees) situated above or, more commonly, below the Scheuermann's kyphosis. These scolioses had a mean Cobb angle of 16 degrees, were more often convex to the right than to the left and were significantly more prevalent in girls than in boys. The presence of these kyphoses and scolioses in the same spine, separated by only a few vertebrae, emphasises the importance of the sagittal plane in idiopathic spinal deformities and strongly suggests that idiopathic scoliosis and Scheuermann's disease share a common pathological process

Aims

The aim of this study was to compare outcomes of guided growth and varus osteotomy in treating Kalamchi type II avascular necrosis (AVN) after open reduction and Pemberton acetabuloplasty for developmental dysplasia of the hip (DDH).

Intramedullary nailing of metaphyseal fractures may be associated with deformity as a result of instability after fixation. Our aim was to evaluate the clinical use of Poller screws (blocking screws) as a supplement to stability after fixation with statically locked intramedullary nails of small diameter. We studied, prospectively, 21 tibial fractures, 10 in the proximal third and 11 in the distal third in 20 patients after the insertion of Poller screws over a mean period of 18.5 months (12 to 29). All fractures had united. Healing was evident radiologically at a mean of 5.4 ± 2.1 months (3 to 12) with a mean varus-valgus alignment of −1.0° (−5 to 3) and mean antecurvatum-recurvatum alignment of 1.6° (−6 to 11). The mean loss of reduction between placement of the initial Poller screw and follow-up was 0.5° in the frontal plane and 0.4° in the sagittal plane. There were no complications related to the Poller screw. The clinical outcome, according to the Karström-Olerud score, was not influenced by previous or concomitant injuries in 18 patients and was judged as excellent in three (17%), good in seven (39%), satisfactory in six (33%), fair in one (6%), and poor in one (6%)

Aims

This study compared the cobalt and chromium serum ion concentration of patients treated with two different metal-on-metal (MoM) hinged total knee arthroplasty (TKA) systems, as well as a titanium nitride (TiN)-coated variant.

Aims

Surgical reconstruction of deformed Charcot feet carries a high risk of nonunion, metalwork failure, and deformity recurrence. The primary aim of this study was to identify the factors contributing to these complications following hindfoot Charcot reconstructions.

Aims

The aim of the study was to compare two methods of calculating pelvic incidence (PI) and pelvic tilt (PT), either by using the femoral heads or acetabular domes to determine the bicoxofemoral axis, in patients with unilateral or bilateral primary hip osteoarthritis (OA).

We treated 50 patients with fractures of the waist of the scaphoid in a below-elbow plaster cast for up to 13 weeks. Displacement of the fragments was assessed independently by two observers using MRI and radiographs performed within two weeks of injury. The MRI assessments showed that only the measurement of sagittal translation of the fragments and an overall assessment of displacement had satisfactory inter- and intra-observer reproducibility and revealed that nine of the 50 fractures were displaced. Only three of the 49 fractures with adequate follow-up failed to unite, and all were displaced with more than 1 mm of translation in the sagittal plane. If the MRI assessment of displacement of the fracture was used as the measurement of choice, assessment of displacement on the initial scaphoid series of radiographs showed a sensitivity of between 33% and 47% and a positive predictive value of between 27% and 86%. Neither observer was able correctly to identify more than 33% to 47% of the displaced fractures from the plain radiographs. Although the overall assessment of displacement and gapping and translation in the coronal plane on the plain radiographs influenced the rate of union, none of these parameters identified all three fractures which failed to unite. We conclude that the assessment of displacement of scaphoid fractures on MRI can probably be used to assess the likelihood of union although the small number of nonunions limits the power of the study. In contrast, the assessment of displacement on routine radiography is inaccurate and of less value in predicting union

The development of spinal deformity in children with underlying neurodisability can affect their ability to function and impact on their quality of life, as well as compromise provision of nursing care. Patients with neuromuscular spinal deformity are among the most challenging due to the number and complexity of medical comorbidities that increase the risk for severe intraoperative or postoperative complications. A multidisciplinary approach is mandatory at every stage to ensure that all nonoperative measures have been applied, and that the treatment goals have been clearly defined and agreed with the family. This will involve input from multiple specialities, including allied healthcare professionals, such as physiotherapists and wheelchair services. Surgery should be considered when there is significant impact on the patients’ quality of life, which is usually due to poor sitting balance, back or costo-pelvic pain, respiratory complications, or problems with self-care and feeding. Meticulous preoperative assessment is required, along with careful consideration of the nature of the deformity and the problems that it is causing. Surgery can achieve good curve correction and results in high levels of satisfaction from the patients and their caregivers. Modern modular posterior instrumentation systems allow an effective deformity correction. However, the risks of surgery remain high, and involvement of the family at all stages of decision-making is required in order to balance the risks and anticipated gains of the procedure, and to select those patients who can mostly benefit from spinal correction.