Aims. Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation. Methods. A total of 122 patients who underwent reconstruction following resection of periacetabular tumour between January 2011 and January 2020 were studied. The risk factors for dislocation were investigated with univariate and multivariate logistic regression analysis on patient-specific, resection-specific, and reconstruction-specific variables. Results. The dislocation rate was 13.9% (n = 17). The hip COR was found to be significantly shifted anteriorly and inferiorly in most patients in the dislocation group compared with the non-dislocation group. Three independent risk factors were found to be related to dislocation: resection of gluteus medius (odds ratio (OR) 3.68 (95% confidence interval (CI) 1.24 to 19.70); p = 0.039), vertical shift of COR > 18 mm (OR 24.8 (95% CI 6.23 to 128.00); p = 0.001), and sagittal shift of COR > 20 mm (OR 6.22 (95% CI 1.33 to 32.2); p = 0.026). Conclusion. Among the 17 patients who dislocated, 70.3% (n = 12) were anterior dislocations. Three independent risk factors were identified, suggesting the importance of proper restoration of the COR and the role of the gluteus medius in maintaining hip joint stability. Cite this article: Bone Joint J 2022;104-B(10):1180–1188

Aims. In recent conflicts, most injuries to the limbs are due to blasts resulting in a large number of lower limb amputations. These lead to heterotopic ossification (HO), phantom limb pain (PLP), and functional deficit. The mechanism of blast loading produces a combined fracture and amputation. Therefore, to study these conditions, in vivo models that replicate this combined effect are required. The aim of this study is to develop a preclinical model of blast-induced lower limb amputation. Methods. Cadaveric Sprague-Dawley rats’ left hindlimbs were exposed to blast waves of 7 to 13 bar burst pressures and 7.76 ms to 12.68 ms positive duration using a shock tube. Radiographs and dissection were used to identify the injuries. Results. Higher burst pressures of 13 and 12 bar caused multiple fractures at the hip, and the right and left limbs. Lowering the pressure to 10 bar eliminated hip fractures; however, the remaining fractures were not isolated to the left limb. Further reducing the pressure to 9 bar resulted in the desired isolated fracture of the left tibia with a dramatic reduction in the fractures to other sites. Conclusion. In this paper, a rodent blast injury model has been developed in the hindlimb of cadaveric rats that combines the blast and fracture in one insult, necessitating amputation. Experimental setup with 9 bar burst pressure and 9.13 ms positive duration created a fracture at the tibia with total reduction in non-targeted fractures, rendering 9 bar burst pressure suitable for translation to a survivable model to investigate blast injury-associated diseases. Cite this article: Bone Joint Res 2021;10(3):166–173

Aims. Periprosthetic joint infections (PJIs) are rare, but represent a great burden for the patient. In addition, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) is increasing. The aim of this rat experiment was therefore to compare the antibiotics commonly used in the treatment of PJIs caused by MRSA. Methods. For this purpose, sterilized steel implants were implanted into the femur of 77 rats. The metal devices were inoculated with suspensions of two different MRSA strains. The animals were divided into groups and treated with vancomycin, linezolid, cotrimoxazole, or rifampin as monotherapy, or with combination of antibiotics over a period of 14 days. After a two-day antibiotic-free interval, the implant was explanted, and bone, muscle, and periarticular tissue were microbiologically analyzed. Results. Vancomycin and linezolid were able to significantly (p < 0.05) reduce the MRSA bacterial count at implants. No significant effect was found at the bone. Rifampin was the only monotherapy that significantly reduced the bacterial count on implant and bone. The combination with vancomycin or linezolid showed significant efficacy. Treatment with cotrimoxazole alone did not achieve a significant bacterial count reduction. The combination of linezolid plus rifampin was significantly more effective on implant and bone than the control group in both trials. Conclusion. Although rifampicin is effective as a monotherapy, it should not be used because of the high rate of resistance development. Our animal experiments showed the great importance of combination antibiotic therapies. In the future, investigations with higher case numbers, varied bacterial concentrations, and changes in individual drug dosages will be necessary to be able to draw an exact comparison, possibly within a clinical trial. Cite this article: Bone Joint Res 2022;11(3):143–151

Aims. Surgery is often indicated in patients with metastatic bone disease (MBD) to improve pain and maximize function. Few studies are available which report on clinically meaningful outcomes such as quality of life, function, and pain relief after surgery for MBD. This is the published protocol for the Bone Metastasis Audit — Patient Reported Outcomes (BoMA-PRO) multicentre MBD study. The primary objective is to ascertain patient-reported quality of life at three to 24 months post-surgery for MBD. Methods. This will be a prospective, longitudinal study across six UK orthopaedic centres powered to identify the influence of ten patient variables on quality of life at three months after surgery for MBD. Adult patients managed for bone metastases will be screened by their treating consultant and posted out participant materials. If they opt in to participate, they will receive questionnaire packs at regular intervals from three to 24 months post-surgery and their electronic records will be screened until death or five years from recruitment. The primary outcome is quality of life as measured by the European Organisation for Research and the Treatment of Cancer Quality of Life questionnaire (EORTC-QLQ) C30 questionnaire. The protocol has been approved by the Newcastle & North Tyneside 2 Research Ethics Committee (REC ref 19/NE/0303) and the study is funded by the Royal College of Physicians and Surgeons of Glasgow (RCPSG) and the Association for Cancer Surgery (BASO-ACS). Discussion. This will be the first powered study internationally to investigate patient-reported outcomes after orthopaedic treatment for bone metastases. We will assess quality of life, function, and pain relief at three to 24 months post-surgery and identify which patient variables are significantly associated with a good outcome after MBD treatment. Cite this article: Bone Jt Open 2021;2(2):79–85

Aims. To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. Methods. This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining. Results. Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues. Conclusion. Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375–1383

Aims. There is increasing evidence that flexible flatfoot (FF) can lead to symptoms and impairment in health-related quality of life. As such we undertook an observational study investigating the aetiology of this condition, to help inform management. The hypothesis was that as well as increased body mass index (BMI) and increased flexibility of the lower limb, an absent anterior subtalar articulation would be associated with a flatter foot posture. . Patients and Methods. A total of 84 children aged between eight and 15 years old were prospectively recruited. The BMI for each child was calculated, flexibility was assessed using the lower limb assessment scale (LLAS) and foot posture was quantified using the arch height index (AHI). Each child underwent a sagittal T1-weighted MRI scan of at least one foot. . Results. An absent anterior subtalar articulation (p < 0.001) and increased LLAS (p = 0.001) predicted a low AHI. BMI was not a significant predictive factor (p = 0.566). . Conclusion. This is the first study to demonstrate the importance of the morphology of the subtalar joint on the underlying foot posture in vivo. . Take home message: Flexibility of the lower limb and absence of the anterior facet of the subtalar joint are associated with flexible FF and may influence management of this common condition. Cite this article: Bone Joint J 2016;98-B:564–8

Aims. Carpal malalignment after a distal radial fracture occurs due to loss of volar tilt. Several studies have shown that this has an adverse influence on function. We aimed to investigate the magnitude of dorsal tilt that leads to carpal malalignment, whether reduction of dorsal tilt will correct carpal malalignment, and which measure of carpal malalignment is the most useful. Methods. Radiographs of patients with a distal radial fracture were prospectively collected and reviewed. Measurements of carpal malalignment were recorded on the initial radiograph, the radiograph following reduction of the fracture, and after a further interval. Linear regression modelling was used to assess the relationship between dorsal tilt and carpal malalignment. Receiver operating characteristic (ROC) analysis was used to identify which values of dorsal tilt led to carpal malalignment. Results. A total of 250 consecutive patients with 252 distal radial fractures were identified. All measures of carpal alignment were significantly associated with dorsal tilt at each timepoint. This relationship persisted after adjustment for age, sex, and the position of the wrist. Capitate shift consistently had the strongest relationship with dorsal tilt and was the only parameter that was not influenced by age or the position of the wrist. ROC curve analysis identified that abnormal capitate shift was seen with > 9° of dorsal tilt. Conclusion. Carpal malalignment is related to dorsal tilt following a distal radial fracture. Reducing the fracture and improving dorsal tilt will reduce carpal malalignment. Capitate shift is easy to assess visually, unrelated to age and sex, and appears to be the most useful measure of carpal malalignment. The aim during reduction of a distal radial fracture should be to realign the capitate with the axis of the radius and prevent carpal malalignment. Cite this article: Bone Joint J 2020;102-B(1):137–143

Objectives. The medially spherical GMK Sphere (Medacta International AG, Castel San Pietro, Switzerland) total knee arthroplasty (TKA) was previously shown to accommodate lateral rollback while pivoting around a stable medial compartment, aiming to replicate native knee kinematics in which some coronal laxity, especially laterally, is also present. We assess coronal plane kinematics of the GMK Sphere and explore the occurrence and pattern of articular separation during static and dynamic activities. Methods. Using pulsed fluoroscopy and image matching, the coronal kinematics and articular surface separation of 16 well-functioning TKAs were studied during weight-bearing and non-weight-bearing, static, and dynamic activities. The closest distances between the modelled articular surfaces were examined with respect to knee position, and proportions of joint poses exhibiting separation were computed. Results. Overall, 1717 joint poses were analyzed. At a 1.0 mm detection threshold, 37 instances of surface separation were observed in the lateral compartment and four medially (p < 0.001). Separation was activity-dependent, both laterally and medially (p < 0.001), occurring more commonly during static deep flexion in the lateral compartment, and during static rotation in the medial compartment. Lateral separation occurred more frequently than medial during kneeling (7/14 lateral vs 1/14 medial; p = 0.031) and stepping (20/1022 lateral vs 0/1022 medial; p < 0.001). Separation varied significantly between individuals during dynamic activities. Conclusion. No consistent association between closest distances of the articular surfaces and knee position was found during any activity. Lift-off was infrequent and depended on the activity performed and the individual knee. Lateral separation was consistent with the design rationale. Medial lift-off was rare and mostly in non-weight-bearing activities. Cite this article: S. Key, G. Scott, J. G. Stammers, M. A. R. Freeman†, V. Pinskerova, R. E. Field, J. Skinner, S. A. Banks. Does lateral lift-off occur in static and dynamic activity in a medially spherical total knee arthroplasty? A pulsed-fluoroscopic investigation. Bone Joint Res 2019;8:207–215. DOI: 10.1302/2046-3758.85.BJR-2018-0237.R1

An electromyographic investigation of patients with subluxation of the patella has been carried out on the parts of the extensor apparatus which actively contribute to the alignment of the patella, both before and after the operation to correct this disorder. The electromyographic pictures have revealed a sharp fall in the activity of the vastus medialis, with full recovery to normal values after a corrective operation. Even if the aligning function of the patella is altered by a variety of factors, the present study confirms the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism

Objectives. Secondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs. Methods. Synthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests. Results. The method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface. Conclusions. This study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition. Cite this article: A. MacLeod, A. H. R. W. Simpson, P. Pankaj. Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices. Bone Joint Res 2018;7:111–120. DOI: 10.1302/2046-3758.71.BJR-2017-0074.R2

There are many reasons why a total knee replacement (TKR) may fail and qualify for revision. Successful revision surgery depends as much on accurate assessment of the problem TKR as it does on revision implant design and surgical technique. Specific modes of failure require specific surgical solutions. Causes of failure are often presented as a list or catalogue, without a system or process for making a decision. In addition, strict definitions and consensus on modes of failure are lacking in published series and registry data. How we approach the problem TKR is an essential but neglected aspect of understanding knee replacement surgery. It must be carried out systematically, comprehensively and efficiently. Eight modes of failure are described: 1) sepsis; 2) extensor discontinuity; 3) stiffness; 4) tibial- femoral instability; 5) patellar tracking; 6) aseptic loosening and osteolysis; 7) periprosthetic fracture and 8) component breakage. A ninth ‘category’, unexplained pain is an indication for further investigation but not surgery. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):105–11

There are eight reported cases in the literature of osteosarcomas secreting β-hCG. Our primary aim was to investigate the rate of β-hCG expression in osteosarcoma and attempt to understand the characteristics of osteosarcomas that secrete β-hCG. We reviewed 37 histopathology slides (14 biopsies and 23 surgical specimens) from 32 patients with osteosarcoma. The slides were retrospectively stained for β-hCG expression. Patient and tumour characteristics, including age, gender, tumour location, subtype, proportion of necrosis, presence of metastases and recurrence were recorded. A total of five of the 32 tumours were found to be positive for β-hCG expression (one strongly and four weakly). This incidence of this expression was found in tumours with poor histological response to neoadjuvant chemotherapy. The use of β-hCG expression as a diagnostic, prognostic or follow-up marker is questionable and needs further investigation with a larger sample size

We reviewed 188 patients at one to 20 years (mean 9.5) after surgery for anterior shoulder instability. Twenty-one had shown bilateral instability at the time of surgery, and 26 of the remaining 167 subsequently developed instability of the contralateral shoulder, giving an overall incidence of 24% bilateral involvement. Fourteen of these patients ultimately required bilateral surgery. The onset of contralateral instability was at one month to 15 years (mean 5.7 years) after anterior repair of the operated shoulder, the cumulative incidence increasing with time (p less than 0.01). The incidence was significantly higher in those under 15 years at the time of initial dislocation or under 18 at the time of surgery. One-half of the patients with contralateral instability had signs of posterior instability at follow-up. Other predisposing factors included having sustained the initial injury to the operated shoulder as a result of minimal trauma, and persistence of a sensation of instability in the operated shoulder. Factors which were not statistically significant included sex, dominant side, athletic activity, work history, and whether the initial surgery was for recurrent subluxations or dislocations. The high prevalence of bilateral shoulder instability suggests an intrinsic abnormality such as capsular and ligamentous laxity or muscle imbalance and warrants further investigations

We used gadolinium-enhanced fat-suppressed MRI to investigate 67 patients with persistent pain after lumbar discectomy. Twenty-five patients had reoperations for lesions diagnosed in this way. Eleven were for recurrent disc prolapse at the same level and sciatica was relieved by all but one. Five operations were for prolapse at an adjacent level and all were successful. The diagnosis of sepsis was less precise, but extension of tissue enhancement into the operated disc space was found to be significant. Only three patients had evidence of arachnoiditis which suggests that this condition has been too often diagnosed as a cause of persisting low back pain

Aims

The purpose of the present study was to compare patient-specific instrumentation (PSI) and conventional surgical instrumentation (CSI) for total knee arthroplasty (TKA) in terms of early implant migration, alignment, surgical resources, patient outcomes, and costs.

The term mid-flexion instability has entered the orthopaedic literature as a concept, but has not been confirmed as a distinct clinical entity. The term is used freely, sometimes as a synonym for flexion instability. However, the terms need to be clearly separated. A cadaver study published in 1990 associated joint line elevation with decreased stability at many angles of flexion, but that model was not typical of clinical scenarios. The literature is considered and it is proposed that the more common entity of an uncorrected flexion contracture after a measured resection arthroplasty technique is more likely to produce clinical findings that suggest instability mid-flexion.

It is proposed that the clinical scenario encountered is generalised instability, with the appearance of stability in full extension from tight posterior structures.

This paper seeks to clarify whether mid-flexion instability exists as an entity distinct from other commonly recognised forms of instability.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):84–8.

The augmentation of fixation with bone cement is increasingly being used in the treatment of severe osteoporotic fractures. We investigated the influence of bone quality on the mechanics of augmentation of plate fixation in a distal femoral fracture model (AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral models were randomly assigned to either an augmented or a non-augmented group. Fixation was performed using a locking compression plate. In the augmented group additionally 1 ml of bone cement was injected into the screw hole before insertion of the screw. Biomechanical testing was performed in axial sinusoidal loading. Augmentation significantly reduced the cut-out distance in the osteoporotic models by about 67% (non-augmented mean 0.30 mm (. sd. 0.08) vs augmented 0.13 mm (. sd. 0.06); p = 0.017). There was no statistical reduction in this distance following augmentation in the non-osteoporotic models (non-augmented mean 0.15 mm (. sd. 0.02) vs augmented 0.15 mm (. sd. 0.07); p = 0.915). In the osteoporotic models, augmentation significantly increased stability (p = 0.017). Cite this article: Bone Joint J 2013;95-B:1406–9

A study of the contamination of suckers used during total hip replacement has been undertaken. Thirty suckers used throughout the operation had their tips cultured: from 11 of these bacteria were grown. The organisms found were those which have previously been implicated in deep infection of total hip replacements. In subsequent operations a further 31 suckers were used for cleaning only the femoral shaft; of these only one was contaminated. This suggests that sucker contamination is related to how long the sucker is in use; consequently it is recommended that a new sucker be used for the preparation of the femoral shaft.

This paper reports a prospective study of the value of ultrasonography in detecting lesions of the lumbar spine in patients with compressive sciatica. The measurements of the diameter of the spinal canal obtained by using ultrasound were compared with the findings at operation in 17 patients in whom a total of 50 sites were examined. The ultrasound beam failed to penetrate the spinal canal at 15 sites and at only 10 of the remaining 35 sites did the ultrasound correctly detect narrowing. It is concluded that ultrasonography is unreliable in identifying the site of compression of the spinal cord and nerve roots. The technical limitations and the probable causes of failure of the technique are discussed.

The osteoinductive properties of demineralised bone matrix have been demonstrated in animal studies. However, its therapeutic efficacy has yet to be proven in humans. The clinical properties of AlloMatrix, an injectable calcium-based demineralised bone matrix allograft, were studied in a prospective randomised study of 50 patients with an isolated unstable distal radial fracture treated by reduction and Kirschner (K-) wire fixation. A total of 24 patients were randomised to the graft group (13 men and 11 women, mean age 42.3 years (20 to 62)) and 26 to the no graft group (8 men and 18 women, mean age 45.0 years (17 to 69)).

At one, three, six and nine weeks, and six and 12 months post-operatively, patients underwent radiological evaluation, assessments for range of movement, grip and pinch strength, and also completed the Disabilities of Arm, Shoulder and Hand questionnaire. At one and six weeks and one year post-operatively, bone mineral density evaluations of both wrists were performed.

No significant difference in wrist function and speed of recovery, rate of union, complications or bone mineral density was found between the two groups. The operating time was significantly higher in the graft group (p = 0.004). Radiologically, the reduction parameters remained similar in the two groups and all AlloMatrix extraosseous leakages disappeared after nine weeks.

This prospective randomised controlled trial did not demonstrate a beneficial effect of AlloMatrix demineralised bone matrix in the treatment of this category of distal radial fractures treated by K-wire fixation.

Cite this article: Bone Joint J 2013;95-B:1514–20.

In rabbits, repair of incisions in the central part of the meniscus has been demonstrated after surgical excision of the peripheral rim. Healing took place via a highly cellular but relatively avascular fibrous tissue stroma which proliferated from the synovial margin and invaded along the cut edge of the meniscus. Suturing facilitated this healing process by providing stability and possibly by supplying bridges for synovial cells to migrate onto the meniscus. Transformation of fibrous tissue into fibrocartilage has also been observed.

Aims

To our knowledge, there is currently no information available about the rate of venous thromboembolism (VTE) or recommendations regarding chemoprophylaxis for patients whose lower limb is immobilized in a plaster cast. We report a retrospective case series assessing the rate of symptomatic VTE in patients treated with a lower limb cast. Given the complex, heterogeneous nature of this group of patients, with many risk factors for VTE, we hypothesized that the rate of VTE would be higher than in the general population.

The lumbar spines of 485 skeletons of adult South African "Whites" and "Blacks" of both sexes were examined to determine the incidence and morphology of defects in the pars interarticularis. The overall incidence was 3.5%, without significant variation between races and sexes. The incidence of lumbar spina bifida in the whole sample was 1.9%, but was 11.8% in those skeletons with spondylolysis. Some instances of unilateral spondylolysis demonstrated obvious callus formation, suggesting a capability for normal repair. It is possible that the defects in bilateral cases represent established non-union of fractures of the pars interarticularis resulting from excessive mobility, and are not due to dysplasia of bone. It is noted, for the first time, that the superior facets of affected vertebrae are abnormally enlarged, and that the inferior facets of the separate neural arch are characteristically elliptical.

We have studied the ability of a range of antibiotics to penetrate intervertebral disc tissue in vitro, using a mouse disc model. Equilibrium concentrations of antibiotics incorporated into the entire disc were determined by bioassay using a microbial growth-inhibition method. Uptake was significantly higher with positively-charged aminoglycosides compared with negatively-charged penicillins and cephalosporins. Uncharged ciprofloxacin showed an intermediate degree of uptake. Our results support the hypothesis that electrostatic interaction between charged antibiotics and negatively-charged glycosaminoglycans in the disc is an important factor in antibiotic penetration, and may explain their differential uptake.

A prospective nation-wide study of knee arthroplasty has been under way in Sweden since October 1975. By the end of 1983, 4505 arthroplasties for osteoarthritis and 3495 for rheumatoid arthritis had been recorded and reviewed one, three and six years after the operation. Using actuarial methods, the probability of the prosthesis remaining in situ after six years was calculated. In osteoarthritis this probability ranged from 65% for hinged prostheses to 90% for medial compartment prostheses. Two-and three-compartment prostheses produced intermediate results with 87% survival. In rheumatoid arthritis the probability varied from 72% for medial compartment prostheses to 90% for two- and three-compartment prostheses. The main reason for failure was loosening of the components, the second most common was infection. The probability of revision for infection by six years was 2% in osteoarthritis and 3% in rheumatoid arthritis. Most revisions were to a three-compartment prosthesis. Knee fusion at primary revision was required in 2% of the cases at six years.

Lumbosacral nerve root anomalies have been documented in the literature for over 30 years; however, no significant quantitative studies have been undertaken so far. We describe parallel studies of 100 cadaveric specimens and an equal number of metrizamide myelograms. The anatomical specimens were prepared by wide deroofing of the lumbar canal to permit precise examination of individual nerve roots and their intradural and extradural connections. The incidence of nerve root anomalies was 14%, the L5-S1 level being most commonly involved. In sharp contrast the incidence of nerve root anomalies determined by myelography was only 4%. The anomalies were classified into four groups and the diagnostic and practical implications of our findings are discussed.

A method for direct measurement of the local pressures in the acetabular cartilage is described. Pressure transducers were introduced into the subchondral bone and positioned there in contrast with the cartilage: the transducers were calibrated in situ. Twelve cadaveric hips were prepared in this way and the pressures were measured with the joint loaded in flexion, extension, abduction, adduction, and in lateral and medial rotation. The highest pressures were recorded in the anterior and posterior segments of the acetabulum; the lowest pressures were constantly found at the zenith of the joint. The relationship of these findings to the pathogenesis of osteoarthritis is considered.

Our purpose was to determine whether continuous passive motion enhanced the quality of knee ligament reconstruction using carbon fibre. In 46 rabbits the medial collateral ligaments were excised and replaced with carbon fibre prostheses. The animals were treated postoperatively by either continuous passive motion, cast immobilisation or cage activity, termed intermittent active motion. At six weeks, the ligaments were compared histologically and biomechanically with normal (control) medial collateral ligaments and with sham-operated controls. The ligaments treated with continuous passive motion were superior to those in the other two treatment groups. There were no ligament failures in any of the groups. This study suggests that continuous passive motion, initiated immediately postoperatively, enhances the biomechanical properties of carbon fibre ligament replacement of the medial collateral ligament while preventing the harmful effects of joint immobilisation.

The release of gentamicin sulphate, sodium fusidate and diethanolamine fusidate from Palacos and CMW cements was studied using elution and serial plate transfer tests. Further tests were made to assay the drug remaining in the cement after antibacterial activity could no longer be detected by the above methods, to detect the sustained slow release of the residual drug, and to ascertain the mechanism of release. The results confirmed that the release of gentamicin sulphate could be detected for longer from Palacos cement than from CMW cement, but the opposite was true for sodium fusidate. Little difference was found in the case of diethanolamine fusidate. Comparison of elution and serial plate transfer tests, and of results of elution in buffers of different pH, demonstrated that the test method employed had a significant effect on the results, and the omission of details of methodology from some publications made comparison and evaluation of results difficult. Varying quantities of residual drug were found in cement from which antibacterial activity could no longer be demonstrated; further tests for sustained, slow release showed that the antibiotic did not remain fixed in the cement but was released at a rate too slow to be detected in the elution and serial plate transfer tests. It is concluded that antibiotics are released from the cement by a process of diffusion, but tests to determine the mechanism of diffusion were unhelpful. The theory of diffusion of drugs through solid matrices, and the clinical implications of the experimental findings, are discussed.

Aims. The aim of this study was to investigate the agreement in interpretation of the quality of the paediatric hip ultrasound examination, the reliability of geometric and morphological assessment, and the relationship between these measurements. Methods. Four investigators evaluated 60 hip ultrasounds and assessed their quality based the standard plane of Graf et al. They measured geometric parameters, described the morphology of the hip, and assigned the Graf grade of dysplasia. They analyzed one self-selected image and one randomly selected image from the ultrasound series, and repeated the process four weeks later. The intra- and interobserver agreement, and correlations between various parameters were analyzed. Results. In the assessment of quality, there a was moderate to substantial intraobserver agreement for each element investigated, but interobserver agreement was poor. Morphological features showed weak to moderate agreement across all parameters but improved to significant when responses were reduced. The geometric measurements showed nearly perfect agreement, and the relationship between them and the morphological features showed a dose response across all parameters with moderate to substantial correlations. There were strong correlations between geometric measurements. The Graf classification showed a fair to moderate interobserver agreement, and moderate to substantial intraobserver agreement. Conclusion. This investigation into the reliability of the interpretation of hip ultrasound scans identified the difficulties in defining what is a high-quality ultrasound. We confirmed that geometric measurements are reliably interpreted and may be useful as a further measurement of quality. Morphological features are generally poorly interpreted, but a simpler binary classification considerably improves agreement. As there is a clear dose response relationship between geometric and morphological measurements, the importance of morphology in the diagnosis of hip dysplasia should be questioned. Cite this article: Bone Joint J 2023;105-B(10):1123–1130

Aims. The aims of this study were to identify and evaluate the current literature examining the prognostic factors which are associated with failure of total elbow arthroplasty (TEA). Methods. Electronic literature searches were conducted using MEDLINE, Embase, PubMed, and Cochrane. All studies reporting prognostic estimates for factors associated with the revision of a primary TEA were included. The risk of bias was assessed using the Quality In Prognosis Studies (QUIPS) tool, and the quality of evidence was assessed using the modified Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework. Due to low quality of the evidence and the heterogeneous nature of the studies, a narrative synthesis was used. Results. A total of 19 studies met the inclusion criteria, investigating 28 possible prognostic factors. Most QUIPS domains (84%) were rated as moderate to high risk of bias. The quality of the evidence was low or very low for all prognostic factors. In low-quality evidence, prognostic factors with consistent associations with failure of TEA in more than one study were: the sequelae of trauma leading to TEA, either independently or combined with acute trauma, and male sex. Several other studies investigating sex reported no association. The evidence for other factors was of very low quality and mostly involved exploratory studies. Conclusion. The current evidence investigating the prognostic factors associated with failure of TEA is of low or very low quality, and studies generally have a moderate to high risk of bias. Prognostic factors are subject to uncertainty, should be interpreted with caution, and are of little clinical value. Higher-quality evidence is required to determine robust prognostic factors for failure of TEA. Cite this article: Bone Joint Res 2024;13(5):201–213

Aims. Most patients with advanced malignancy suffer bone metastases, which pose a significant challenge to orthopaedic services and burden to the health economy. This study aimed to assess adherence to the British Orthopaedic Oncology Society (BOOS)/British Orthopaedic Association (BOA) guidelines on patients with metastatic bone disease (MBD) in the UK. Methods. A prospective, multicentre, national collaborative audit was designed and delivered by a trainee-led collaborative group. Data were collected over three months (1 April 2021 to 30 June 2021) for all patients presenting with MBD. A data collection tool allowed investigators at each hospital to compare practice against guidelines. Data were collated and analyzed centrally to quantify compliance from 84 hospitals in the UK for a total of 1,137 patients who were eligible for inclusion. Results. A total of 846 patients with pelvic and appendicular MBD were analyzed, after excluding those with only spinal metastatic disease. A designated MBD lead was not present in 39% of centres (33/84). Adequate radiographs were not performed in 19% of patients (160/846), and 29% (247/846) did not have an up-to-date CT of thorax, abdomen, and pelvis to stage their disease. Compliance was low obtaining an oncological opinion (69%; 584/846) and prognosis estimations (38%; 223/846). Surgery was performed in 38% of patients (319/846), with the rates of up-to-date radiological investigations and oncology input with prognosis below the expected standard. Of the 25% (215/846) presenting with a solitary metastasis, a tertiary opinion from a MBD centre and biopsy was sought in 60% (130/215). Conclusion. Current practice in the UK does not comply with national guidelines, especially regarding investigations prior to surgery and for patients with solitary metastases. This study highlights the need for investment and improvement in care. The recent publication of British Orthopaedic Association Standards for Trauma (BOAST) defines auditable standards to drive these improvements for this vulnerable patient group. Cite this article: Bone Joint J 2023;105-B(10):1115–1122

Aims. Metal particles detached from metal-on-metal hip prostheses (MoM-THA) have been shown to cause inflammation and destruction of tissues. To further explore this, we investigated the histopathology (aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) score) and metal concentrations of the periprosthetic tissues obtained from patients who underwent revision knee arthroplasty. We also aimed to investigate whether accumulated metal debris was associated with ALVAL-type reactions in the synovium. Methods. Periprosthetic metal concentrations in the synovia and histopathological samples were analyzed from 230 patients from our institution from October 2016 to December 2019. An ordinal regression model was calculated to investigate the effect of the accumulated metals on the histopathological reaction of the synovia. Results. Median metal concentrations were as follows: cobalt: 0.69 μg/g (interquartile range (IQR) 0.10 to 6.10); chromium: 1.1 μg/g (IQR 0.27 to 4.10); and titanium: 1.6 μg/g (IQR 0.90 to 4.07). Moderate ALVAL scores were found in 30% (n = 39) of the revised knees. There were ten patients with an ALVAL score of 6 or more who were revised for suspected periprosthetic joint infection (PJI), aseptic loosening, or osteolysis. R2 varied between 0.269 and 0.369 for the ordinal regression models. The most important variables were model type, indication for revision, and cobalt and chromium in the ordinal regression models. Conclusion. We found that metal particles released from the knee prosthesis can accumulate in the periprosthetic tissues. Several patients revised for suspected culture-negative PJI had features of an ALVAL reaction, which is a novel finding. Therefore, ALVAL-type reactions can also be found around knee prostheses, but they are mostly mild and less common than those found around metal-on-metal prostheses. Cite this article: Bone Joint Res 2024;13(4):149–156

Aims. The primary aims of this study were to determine the time to sonographic correction of decentred hips during treatment with Pavlik harness for developmental dysplasia of the hip (DDH) and investigate potential risk factors for a delayed response to treatment. Methods. This was a retrospective cohort study of infants with decentred hips who underwent a comprehensive management protocol with Pavlik harness between 2012 and 2016. Ultrasound assessments were performed at standardized intervals and time to correction from centring of the femoral head was quantified. Hips with < 40% femoral head coverage (FHC) were considered decentred, and hips with > 50% FHC and α angles > 60° were considered corrected. Survival analyses using log-rank tests and Cox regression were performed to investigate potential risk factors for delayed time to correction. Results. A total of 108 infants (158 hips) successfully completed the bracing protocol and were included in the study. Mean age at treatment initiation was 6.9 weeks (SD 3.8). All included hips centred within two weeks of treatment initiation. At two, five, eight, and 12 weeks following centring of the femoral head, 13% (95% CI 8 to 19), 67% (95% CI 60 to 74), 98% (95% CI 95 to 99), and 99% (95% CI 98 to 100) of hips had cumulatively achieved sonographic correction, respectively. Low α angles at presentation were found to be a risk factor for delayed time to correction (hazard ratio per 1° decrease in α angle 1.04 (95% CI 1.01 to 1.06); p = 0.006). Conclusion. The majority of decentred hips undergoing Pavlik treatment achieved sonographic correction within eight weeks of centring and radiological severity at presentation was a predictor for slower recovery. These findings provide valuable insights into hip development during Pavlik treatment and will inform the design of future prospective studies investigating the optimal time required in harness. Cite this article: Bone Joint J 2025;107-B(1):118–123

Aims. The Single Assessment Numerical Evalution (SANE) score is a pragmatic alternative to longer patient-reported outcome measures (PROMs). The purpose of this study was to investigate the concurrent validity of the SANE and hip-specific PROMs in a generalized population of patients with hip pain at a single timepoint upon initial visit with an orthopaedic surgeon who is a hip preservation specialist. We hypothesized that SANE would have a strong correlation with the 12-question International Hip Outcome Tool (iHOT)-12, the Hip Outcome Score (HOS), and the Hip disability and Osteoarthritis Outcome Score (HOOS), providing evidence for concurrent validity of the SANE and hip-specific outcome measures in patients with hip pain. Methods. This study was a cross-sectional retrospective database analysis at a single timepoint. Data were collected from 2,782 patients at initial evaluation with a hip preservation specialist using the iHOT-12, HOS, HOOS, and SANE. Outcome scores were retrospectively analyzed using Pearson correlation coefficients. Results. Mean raw scores were iHOT-12 67.01 (SD 29.52), HOS 58.42 (SD 26.26), HOOS 86.85 (SD 32.94), and SANE 49.60 (SD 27.92). SANE was moderately correlated with the iHOT-12 (r = -0.4; 95% CI -0.35 to -0.44; p < 0.001), HOS (r = 0.57; 95% CI 0.53 to 0.60; p < 0.001), and HOOS (r = -0.55; 95% CI -0.51 to -0.58; p < 0.001). The iHOT-12 and HOOS were recorded as a lower score, indicating better function, which accounts for the negative r values. Conclusion. This study was the first to investigate the relationship between the SANE and the iHOT-12, HOS, and HOOS in a population of patients with hip pain at the initial evaluation with an orthopaedic surgeon, and found moderate correlation between SANE and the iHOT-12, HOS, and HOOS. The SANE may be a pragmatic alternative for clinical benchmarking in a general population of patients with hip pain. The construct validity of the SANE should be questioned compared to legacy measures whose content validity has been more rigorously investigated. Cite this article: Bone Jt Open 2024;5(10):904–910

Aims. The present study investigated receptor activator of nuclear factor kappa-Β ligand (RANKL), osteoprotegerin (OPG), and Runt-related transcription factor 2 (RUNX2) gene expressions in giant cell tumour of bone (GCTB) patients in relationship with tumour recurrence. We also aimed to investigate the influence of CpG methylation on the transcriptional levels of RANKL and OPG. Methods. A total of 32 GCTB tissue samples were analyzed, and the expression of RANKL, OPG, and RUNX2 was evaluated by quantitative polymerase chain reaction (qPCR). The methylation status of RANKL and OPG was also evaluated by quantitative methylation-specific polymerase chain reaction (qMSP). Results. We found that RANKL and RUNX2 gene expression was upregulated more in recurrent than in non-recurrent GCTB tissues, while OPG gene expression was downregulated more in recurrent than in non-recurrent GCTB tissues. Additionally, we proved that changes in DNA methylation contribute to upregulating the expression of RANKL and downregulating the expression of OPG, which are critical for bone homeostasis and GCTB development. Conclusion. Our results suggest that the overexpression of RANKL/RUNX2 and the lower expression of OPG are associated with recurrence in GCTB patients. Cite this article: Bone Joint Res 2024;13(2):84–91

Aims. We investigated the efficacy and safety profile of commonly used venous thromboembolism (VTE) prophylaxis agents following hip and knee arthroplasty. Methods. A systematic search of PubMed, Embase, Cochrane Library, Web of Science, and OrthoSearch was performed. Prophylaxis agents investigated were aspirin (< 325 mg and ≥ 325 mg daily), enoxaparin, dalteparin, fondaparinux, unfractionated heparin, warfarin, rivaroxaban, apixaban, and dabigatran. The primary efficacy outcome of interest was the risk of VTE, whereas the primary safety outcomes of interest were the risk of major bleeding events (MBE) and wound complications (WC). VTE was defined as the confirmed diagnosis of any deep vein thrombosis and/or pulmonary embolism. Network meta-analysis combining direct and indirect evidence was performed. Cluster rank analysis using the surface under cumulative ranking (SUCRA) was applied to compare each intervention group, weighing safety and efficacy outcomes. Results. Of 86 studies eligible studies, cluster rank analysis showed that aspirin < 325 mg daily (SUCRA-VTE 89.3%; SUCRA-MBE 75.3%; SUCRA-WC 71.1%), enoxaparin (SUCRA-VTE 55.7%; SUCRA-MBE 49.8%; SUCRA-WC 45.2%), and dabigatran (SUCRA-VTE 44.9%; SUCRA-MBE 52.0%; SUCRA-WC 41.9%) have an overall satisfactory efficacy and safety profile. Conclusion. We recommend the use of either aspirin < 325 mg daily, enoxaparin, or dabigatran for VTE prophylaxis following hip and knee arthroplasty. Cite this article: Bone Joint J 2024;106-B(9):924–934

Aims. This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation. Methods. In this study, 60 rats were included in a titanium rod implantation model and underwent subsequent guanylate cyclase treatment. Imaging, histology, and biomechanics were used to evaluate the osseointegration of rats in each group. First, the impact of VIT on bone integration in aged rats with iron overload was investigated. Subsequently, VIT was employed to modulate the differentiation of MC3T3-E1 cells and RAW264.7 cells under conditions of iron overload. Results. Utilizing an OVX rat model, we observed significant alterations in bone mass and osseointegration due to VIT administration in aged rats with iron overload. The observed effects were concomitant with reductions in bone metabolism, oxidative stress, and inflammation. To elucidate whether these effects are associated with osteoclast and osteoblast activity, we conducted in vitro experiments using MC3T3-E1 cells and RAW264.7 cells. Our findings indicate that iron accumulation suppressed the activity of MC3T3-E1 while enhancing RAW264.7 function. Furthermore, iron overload significantly decreased oxidative stress levels; however, these detrimental effects can be mitigated by VIT treatment. Conclusion. Collectively, our data provide compelling evidence that VIT has the potential to reverse the deleterious consequences of iron overload on osseointegration and bone mass during ageing. Cite this article: Bone Joint Res 2024;13(9):427–440

Aims. Transcription factor nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of chronic inflammatory diseases in all organ systems. Despite its importance, NF-κB targeted drug therapy to mitigate chronic inflammation has had limited success in preclinical studies. We hypothesized that sex differences affect the response to NF-κB treatment during chronic inflammation in bone. This study investigated the therapeutic effects of NF-κB decoy oligodeoxynucleotides (ODN) during chronic inflammation in male and female mice. Methods. We used a murine model of chronic inflammation induced by continuous intramedullary delivery of lipopolysaccharide-contaminated polyethylene particles (cPE) using an osmotic pump. Specimens were evaluated using micro-CT and histomorphometric analyses. Sex-specific osteogenic and osteoclastic differentiation potentials were also investigated in vitro, including alkaline phosphatase, Alizarin Red, tartrate-resistant acid phosphatase staining, and gene expression using reverse transcription polymerase chain reaction (RT-PCR). Results. Local delivery of NF-κB decoy ODN in vivo increased osteogenesis in males, but not females, in the presence of chronic inflammation induced by cPE. Bone resorption activity was decreased in both sexes. In vitro osteogenic and osteoclastic differentiation assays during inflammatory conditions did not reveal differences among the groups. Receptor activator of nuclear factor kappa Β ligand (Rankl) gene expression by osteoblasts was significantly decreased only in males when treated with ODN. Conclusion. We demonstrated that NF-κB decoy ODN increased osteogenesis in male mice and decreased bone resorption activity in both sexes in preclinical models of chronic inflammation. NF-κB signalling could be a therapeutic target for chronic inflammatory diseases involving bone, especially in males. Cite this article: Bone Joint Res 2024;13(1):28–39

Aims. The aim of this study was to determine the consensus best practice approach for the investigation and management of children (aged 0 to 15 years) in the UK with musculoskeletal infection (including septic arthritis, osteomyelitis, pyomyositis, tenosynovitis, fasciitis, and discitis). This consensus can then be used to ensure consistent, safe care for children in UK hospitals and those elsewhere with similar healthcare systems. Methods. A Delphi approach was used to determine consensus in three core aspects of care: 1) assessment, investigation, and diagnosis; 2) treatment; and 3) service, pathways, and networks. A steering group of paediatric orthopaedic surgeons created statements which were then evaluated through a two-round Delphi survey sent to all members of the British Society for Children’s Orthopaedic Surgery (BSCOS). Statements were only included (‘consensus in’) in the final agreed consensus if at least 75% of respondents scored the statement as critical for inclusion. Statements were discarded (‘consensus out’) if at least 75% of respondents scored them as not important for inclusion. Reporting these results followed the Appraisal Guidelines for Research and Evaluation. Results. A total of 133 children’s orthopaedic surgeons completed the first survey, and 109 the second. Out of 43 proposed statements included in the initial Delphi, 32 reached ‘consensus in’, 0 ‘consensus out’, and 11 ‘no consensus’. These 11 statements were then reworded, amalgamated, or deleted before the second Delphi round of eight statements. All eight were accepted as ‘consensus in’, resulting in a total of 40 approved statements. Conclusion. In the many aspects of medicine where relevant evidence is not available for clinicians to base their practice, a Delphi consensus can provide a strong body of opinion that acts as a benchmark for good quality clinical care. We would recommend clinicians managing children with musculoskeletal infection follow the guidance in the consensus statements in this article, to ensure care in all medical settings is consistent and safe. Cite this article: Bone Joint J 2023;105-B(7):815–820

Aims. 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. Methods. 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)). Results. We identified a negative correlation between PTA and anterior viable areas (rho −0.477; p = 0.001), and no correlation between PTA and necrotic (rho 0.229; p = 0.067) or posterior viable areas (rho 0.204; p = 0.132). Conclusion. Our results suggest that residual posterior tilt after FNF could affect the anteroposterior localization of necrosis. Cite this article: Bone Jt Open 2024;5(5):394–400

Aims. The escalating demand for medical resources to address spinal diseases as society ages is an issue that requires careful evaluation. However, few studies have examined trends in spinal surgery, especially unscheduled hospitalizations or surgeries performed after hours, through large databases. Our study aimed to determine national trends in the number of spine surgeries in Japan. We also aimed to identify trends in after-hours surgeries and unscheduled hospitalizations and their impact on complications and costs. Methods. We retrospectively investigated data extracted from the Diagnosis Procedure Combination database, a representative inpatient database in Japan. The data from April 2010 to March 2020 were used for this study. We included all patients who had undergone any combination of laminectomy, laminoplasty, discectomy, and/or spinal arthrodesis. Results. This investigation included 739,474 spinal surgeries and 739,215 hospitalizations in Japan. There was an average annual increase of 4.6% in the number of spinal surgeries. Scheduled hospitalizations increased by 3.7% per year while unscheduled hospitalizations increased by 11.8% per year. In-hours surgeries increased by 4.5% per year while after-hours surgeries increased by 9.9% per year. Complication rates and costs increased for both after-hours surgery and unscheduled hospitalizations, in comparison to their respective counterparts of in-hours surgery and scheduled hospitalizations. Conclusion. This study provides important insights for those interested in improving spine care in an ageing society. The swift surge in after-hours spinal surgeries and unscheduled hospitalizations highlights that the medical needs of an increasing number of patients due to an ageing society are outpacing the capacity of existing medical resources. Cite this article: Bone Jt Open 2024;5(8):662–670

Aims. This systematic review aims to identify 3D predictors derived from biplanar reconstruction, and to describe current methods for improving curve prediction in patients with mild adolescent idiopathic scoliosis. Methods. A comprehensive search was conducted by three independent investigators on MEDLINE, PubMed, Web of Science, and Cochrane Library. Search terms included “adolescent idiopathic scoliosis”,“3D”, and “progression”. The inclusion and exclusion criteria were carefully defined to include clinical studies. Risk of bias was assessed with the Quality in Prognostic Studies tool (QUIPS) and Appraisal tool for Cross-Sectional Studies (AXIS), and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. In all, 915 publications were identified, with 377 articles subjected to full-text screening; overall, 31 articles were included. Results. Torsion index (TI) and apical vertebral rotation (AVR) were identified as accurate predictors of curve progression in early visits. Initial TI > 3.7° and AVR > 5.8° were predictive of curve progression. Thoracic hypokyphosis was inconsistently observed in progressive curves with weak evidence. While sagittal wedging was observed in mild curves, there is insufficient evidence for its correlation with curve progression. In curves with initial Cobb angle < 25°, Cobb angle was a poor predictor for future curve progression. Prediction accuracy was improved by incorporating serial reconstructions in stepwise layers. However, a lack of post-hoc analysis was identified in studies involving geometrical models. Conclusion. For patients with mild curves, TI and AVR were identified as predictors of curve progression, with TI > 3.7° and AVR > 5.8° found to be important thresholds. Cobb angle acts as a poor predictor in mild curves, and more investigations are required to assess thoracic kyphosis and wedging as predictors. Cumulative reconstruction of radiographs improves prediction accuracy. Comprehensive analysis between progressive and non-progressive curves is recommended to extract meaningful thresholds for clinical prognostication. Cite this article: Bone Jt Open 2024;5(3):243–251

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females’ greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries. Cite this article: Bone Joint J 2023;105-B(10):1033–1037

Aims. 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. Methods. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. Results. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. Conclusion. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events. Cite this article: Bone Jt Open 2023;4(6):416–423

Aims. To evaluate mid-to long-term patient-reported outcome measures (PROMs) of endoprosthetic reconstruction after resection of malignant tumours arising around the knee, and to investigate the risk factors for unfavourable PROMs. Methods. The medical records of 75 patients who underwent surgery between 2000 and 2020 were retrospectively reviewed, and 44 patients who were alive and available for follow-up (at a mean of 9.7 years postoperatively) were included in the study. Leg length discrepancy was measured on whole-leg radiographs, and functional assessment was performed with PROMs (Toronto Extremity Salvage Score (TESS) and Comprehensive Outcome Measure for Musculoskeletal Oncology Lower Extremity (COMMON-LE)) with two different aspects. The thresholds for unfavourable PROMs were determined using anchor questions regarding satisfaction, and the risk factors for unfavourable PROMs were investigated. Results. The thresholds for favourable TESS and COMMON were 64.8 and 70.4 points, respectively. Multivariate analysis showed that age at surgery (p = 0.004) and postoperative leg length discrepancy (p = 0.043) were significant risk factors for unfavourable TESS results, while age at surgery (p < 0.001) was a significant risk factor for unfavourable COMMON-LE results. Following receiver operating characteristic analysis, the threshold for both TESS and COMMON-LE was 29 years of age at surgery. Additionally, a leg length discrepancy of 8.2 mm was the threshold for unfavourable TESS. Conclusion. Patients aged > 29 years at the time of surgery require appropriate preoperative counselling and adequate postoperative physical and socioemotional support. Reconstruction equivalent to the length of the resected bone can reduce the risk of functional disabilities in daily living. Cite this article: Bone Jt Open 2023;4(12):906–913

Aims. This multicentre retrospective observational study’s aims were to investigate whether there are differences in the occurrence of radiolucent lines (RLLs) following total knee arthroplasty (TKA) between the conventional Attune baseplate and its successor, the novel Attune S+, independent from other potentially influencing factors; and whether tibial baseplate design and presence of RLLs are associated with differing risk of revision. Methods. A total of 780 patients (39% male; median age 70.7 years (IQR 62.0 to 77.2)) underwent cemented TKA using the Attune Knee System) at five centres, and with the latest radiograph available for the evaluation of RLL at between six and 36 months from surgery. Univariate and multivariate logistic regression models were performed to assess associations between patient and implant-associated factors on the presence of tibial and femoral RLLs. Differences in revision risk depending on RLLs and tibial baseplate design were investigated with the log-rank test. Results. The conventional and novel Attune baseplates were used in 349 (45%) and 431 (55%) patients, respectively. At a median follow-up of 14 months (IQR 11 to 25), RLLs were present in 29% (n = 228/777) and 15% (n = 116/776) of the tibial and femoral components, respectively, and were more common in the conventional compared to the novel baseplate. The novel baseplate was independently associated with a lower incidence of tibial and femoral RLLs (both regardless of age, sex, BMI, and time to radiograph). One- and three-year revision risk was 1% (95% CI 0.4% to 1.9%)and 6% (95% CI 2.6% to 13.2%), respectively. There was no difference between baseplate design and the presence of RLLs on the the risk of revision at short-term follow-up. Conclusion. The overall incidence of RLLs, as well as the incidence of tibial and femoral RLLs, was lower with the novel compared to the conventional tibial Attune baseplate design, but higher than in the predecessor design and other commonly used TKA systems. Cite this article: Bone Joint J 2024;106-B(11):1240–1248