Aims. Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies. Methods. In 137 robotic-assisted TKAs, extension and flexion stressed gap laxities and bone resections were measured. The primary outcome was the proportion and magnitude of medial and lateral SPI (gap differential > 2.0 mm) for KA, MA, and FA. Secondary outcomes were the proportion of knees with severe (> 4.0 mm) SPI, and resection thicknesses for each technique, with KA as reference. Results. FA showed significantly lower rates of medial and lateral SPI (2.9% and 2.2%) compared to KA (45.3%; p < 0.001, and 25.5%; p < 0.001) and compared to MA (52.6%; p < 0.001 and 29.9%; p < 0.001). There was no difference in medial and lateral SPI between KA and MA (p = 0.228 and p = 0.417, respectively). FA showed significantly lower rates of severe medial and lateral SPI (0 and 0%) compared to KA (8.0%; p < 0.001 and 7.3%; p = 0.001) and compared to MA (10.2%; p < 0.001 and 4.4%; p = 0.013). There was no difference in severe medial and lateral SPI between KA and MA (p = 0.527 and p = 0.307, respectively). MA resulted in thinner resections than KA in medial extension (mean difference (MD) 1.4 mm, SD 1.9; p < 0.001), medial flexion (MD 1.5 mm, SD 1.8; p < 0.001), and lateral extension (MD 1.1 mm, SD 1.9; p < 0.001). FA resulted in thinner resections than KA in medial extension (MD 1.6 mm, SD 1.4; p < 0.001) and lateral extension (MD 2.0 mm, SD 1.6; p < 0.001), but in thicker medial flexion resections (MD 0.8 mm, SD 1.4; p < 0.001). Conclusion. Mechanical and kinematic alignment (measured resection techniques) result in high rates of SPI. Pre-resection angular and translational adjustments with functional alignment, with typically smaller distal than posterior femoral resection, address this issue. Cite this article: Bone Jt Open 2024;5(8):681–687

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Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement.

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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.

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The aims of this study were: 1) to describe extended restricted kinematic alignment (E-rKA), a novel alignment strategy during robotic-assisted total knee arthroplasty (RA-TKA); 2) to compare residual medial compartment tightness following virtual surgical planning during RA-TKA using mechanical alignment (MA) and E-rKA, in the same set of osteoarthritic varus knees; 3) to assess the requirement of soft-tissue releases during RA-TKA using E-rKA; and 4) to compare the accuracy of surgical plan execution between knees managed with adjustments in component positioning alone, and those which require additional soft-tissue releases.

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People with severe, persistent low back pain (LBP) may be offered lumbar spine fusion surgery if they have had insufficient benefit from recommended non-surgical treatments. However, National Institute for Health and Care Excellence (NICE) 2016 guidelines recommended not offering spinal fusion surgery for adults with LBP, except as part of a randomized clinical trial. This survey aims to describe UK clinicians’ views about the suitability of patients for such a future trial, along with their views regarding equipoise for randomizing patients in a future clinical trial comparing lumbar spine fusion surgery to best conservative care (BCC; the FORENSIC-UK trial).

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Patient dissatisfaction is not uncommon following primary total knee arthroplasty. One proposed method to alleviate this is by improving knee kinematics. Therefore, we aimed to answer the following research question: are there significant differences in knee kinematics based on the design of the tibial insert (cruciate-retaining (CR), ultra-congruent (UC), or medial congruent (MC))?

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To investigate the risk factors for unsuccessful radial head reduction (RHR) in children with chronic Monteggia fractures (CMFs) treated surgically.

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To systematically review the predominant complication rates and changes to patient-reported outcome measures (PROMs) following osteochondral allograft (OCA) transplantation for shoulder instability.

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To investigate if preoperative CT improves detection of unstable trochanteric hip fractures.

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Proximal femur fractures treatment can involve anterograde nailing with a single or double cephalic screw. An undesirable failure for this fixation is screw cut-out. In a single-screw nail, a tip-apex distance (TAD) greater than 25 mm has been associated with an increased risk of cut-out. The aim of the study was to examine the role of TAD as a risk factor in a cephalic double-screw nail.

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Gram-negative infections are associated with comorbid patients, but outcomes are less well understood. This study reviewed diagnosis, management, and treatment for a cohort treated in a tertiary spinal centre.

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

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Ilium is the most common site of pelvic Ewing’s sarcoma (ES). Resection of the ilium and iliosacral joint causes pelvic disruption. However, the outcomes of resection and reconstruction are not well described. In this study, we report patients’ outcomes after resection of the ilium and iliosacral ES and reconstruction with a tibial strut allograft.

Aims. The Chopart joint complex is a joint between the midfoot and hindfoot. The static and dynamic support system of the joint is critical for maintaining the medial longitudinal arch of the foot. Any dysfunction leads to progressive collapsing flatfoot deformity (PCFD). Often, the tibialis posterior is the primary cause; however, contrary views have also been expressed. The present investigation intends to explore the comprehensive anatomy of the support system of the Chopart joint complex to gain insight into the cause of PCFD. Methods. The study was conducted on 40 adult embalmed cadaveric lower limbs. Chopart joint complexes were dissected, and the structures supporting the joint inferiorly were observed and noted. Results. The articulating bones exhibit features like a cuboid shelf and navicular beak, which appear to offer inferior support to the joint. The expanse of the spring ligament complex is more medial than inferior, while the superomedial part is more extensive than the intermediate and inferoplantar parts. The spring ligament is reinforced by the tendons in the superomedial part (the main tendon of tibialis posterior), the inferomedial part (the plantar slip of tibialis posterior), and the master knot of Henry positioned just inferior to the gap between the inferomedial and inferoplantar bundles. Conclusion. This study highlights that the medial aspect of the talonavicular articulation has more extensive reinforcement in the form of superomedial part of spring ligament and tibialis posterior tendon. The findings are expected to prompt further research in weightbearing settings on the pathogenesis of flatfoot. Cite this article: Bone Jt Open 2024;5(4):335–342

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Custom triflange acetabular components (CTACs) play an important role in reconstructive orthopaedic surgery, particularly in revision total hip arthroplasty (rTHA) and pelvic tumour resection procedures. Accurate CTAC positioning is essential to successful surgical outcomes. While prior studies have explored CTAC positioning in rTHA, research focusing on tumour cases and implant flange positioning precision remains limited. Additionally, the impact of intraoperative navigation on positioning accuracy warrants further investigation. This study assesses CTAC positioning accuracy in tumour resection and rTHA cases, focusing on the differences between preoperative planning and postoperative implant positions.

Aims. Posterior malleolar (PM) fractures are commonly associated with ankle fractures, pilon fractures, and to a lesser extent tibial shaft fractures. The tibialis posterior (TP) tendon entrapment is a rare complication associated with PM fractures. If undiagnosed, TP entrapment is associated with complications, ranging from reduced range of ankle movement to instability and pes planus deformities, which require further surgeries including radical treatments such as arthrodesis. Methods. The inclusion criteria applied in PubMed, Scopus, and Medline database searches were: all adult studies published between 2012 and 2022; and studies written in English. Outcome of TP entrapment in patients with ankle injuries was assessed by two reviewers independently. Results. Four retrospective studies and eight case reports were accepted in this systematic review. Collectively there were 489 Pilon fractures, 77 of which presented with TP entrapment (15.75%). There were 28 trimalleolar fractures, 12 of which presented with TP entrapment (42.86%). All the case report studies reported inability to reduce the fractures at initial presentation. The diagnosis of TP entrapment was made in the early period in two (25%) cases, and delayed diagnosis in six (75%) cases reported. Using modified Clavien-Dindo complication classification, 60 (67%) of the injuries reported grade IIIa complications and 29 (33%) grade IIIb complications. Conclusion. TP tendon was the commonest tendon injury associated with pilon fracture and, to a lesser extent, trimalleolar ankle fracture. Early identification using a clinical suspicion and CT imaging could lead to early management of TP entrapment in these injuries, which could lead to better patient outcomes and reduced morbidity. Cite this article: Bone Jt Open 2024;5(3):252–259

Aims. The optimal management of posterior malleolar ankle fractures, a prevalent type of ankle trauma, is essential for improved prognosis. However, there remains a debate over the most effective surgical approach, particularly between screw and plate fixation methods. This study aims to investigate the differences in outcomes associated with these fixation techniques. Methods. We conducted a comprehensive review of clinical trials comparing anteroposterior (A-P) screws, posteroanterior (P-A) screws, and plate fixation. Two investigators validated the data sourced from multiple databases (MEDLINE, EMBASE, and Web of Science). Following PRISMA guidelines, we carried out a network meta-analysis (NMA) using visual analogue scale and American Orthopaedic Foot and Ankle Score (AOFAS) as primary outcomes. Secondary outcomes included range of motion limitations, radiological outcomes, and complication rates. Results. The NMA encompassed 13 studies, consisting of four randomized trials and eight retrospective ones. According to the surface under the cumulative ranking curve-based ranking, the A-P screw was ranked highest for improvements in AOFAS and exhibited lowest in infection and peroneal nerve injury incidence. The P-A screws, on the other hand, excelled in terms of VAS score improvements. Conversely, posterior buttress plate fixation showed the least incidence of osteoarthritis grade progression, postoperative articular step-off ≥ 2 mm, nonunions, and loss of ankle dorsiflexion ≥ 5°, though it underperformed in most other clinical outcomes. Conclusion. The NMA suggests that open plating is more likely to provide better radiological outcomes, while screw fixation may have a greater potential for superior functional and pain results. Nevertheless, clinicians should still consider the fragment size and fracture pattern, weighing the advantages of rigid biomechanical fixation against the possibility of soft-tissue damage, to optimize treatment results. Cite this article: Bone Jt Open 2024;5(3):227–235

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Ankle fracture is one of the most common musculoskeletal injuries sustained in the UK. Many patients experience pain and physical impairment, with the consequences of the fracture and its management lasting for several months or even years. The broad aim of ankle fracture treatment is to maintain the alignment of the joint while the fracture heals, and to reduce the risks of problems, such as stiffness. More severe injuries to the ankle are routinely treated surgically. However, even with advances in surgery, there remains a risk of complications; for patients experiencing these, the associated loss of function and quality of life (Qol) is considerable. Non-surgical treatment is an alternative to surgery and involves applying a cast carefully shaped to the patient’s ankle to correct and maintain alignment of the joint with the key benefit being a reduction in the frequency of common complications of surgery. The main potential risk of non-surgical treatment is a loss of alignment with a consequent reduction in ankle function. This study aims to determine whether ankle function, four months after treatment, in patients with unstable ankle fractures treated with close contact casting is not worse than in those treated with surgical intervention, which is the current standard of care.

Aims. Total hip arthroplasty (THA) is a common procedure to address pain and enhance function in hip disorders such as osteoarthritis. Despite its success, postoperative patient recovery exhibits considerable heterogeneity. This study aimed to investigate whether patients follow distinct pain trajectories following THA and identify the patient characteristics linked to suboptimal trajectories. Methods. This retrospective cohort study analyzed THA patients at a large academic centre (NYU Langone Orthopedic Hospital, New York, USA) from January 2018 to January 2023, who completed the Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity questionnaires, collected preoperatively at one-, three-, six-, 12-, and 24-month follow-up times. Growth mixture modelling (GMM) was used to model the trajectories. Optimal model fit was determined by Bayesian information criterion (BIC), Vuong-Lo-Mendell-Rubin likelihood ratio test (VLMR-LRT), posterior probabilities, and entropy values. Association between trajectory groups and patient characteristics were measured by multinomial logistic regression using the three-step approach. Results. Among the 1,249 patients, a piecewise GMM model revealed three distinct pain trajectory groups: 56 patients (4.5%) in group 1; 1,144 patients (91.6%) in group 2; and 49 patients (3.9%) in group 3. Patients in group 2 experienced swift recovery post-THA and minimal preoperative pain. In contrast, groups 1 and 3 initiated with pronounced preoperative pain; however, only group 3 exhibited persistent long-term pain. Multinomial regression indicated African Americans were exceedingly likely to follow trajectory groups 1 (odds ratio (OR) 2.73) and 3 (OR 3.18). Additionally, odds of membership to group 3 increased by 12% for each BMI unit rise, by 19% for each added postoperative day, and by over four if discharged to rehabilitation services (OR 4.07). Conclusion. This study identified three distinct pain trajectories following THA, highlighting the role of individual patient factors in postoperative recovery. This emphasizes the importance of preoperatively addressing modifiable risk factors associated with suboptimal pain trajectories, particularly in at-risk patients. Cite this article: Bone Jt Open 2024;5(3):174–183

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Is it feasible to conduct a definitive multicentre trial in community settings of corticosteroid injections (CSI) and hydrodilation (HD) compared to CSI for patients with frozen shoulder? An adequately powered definitive randomized controlled trial (RCT) delivered in primary care will inform clinicians and the public whether hydrodilation is a clinically and cost-effective intervention. In this study, prior to a full RCT, we propose a feasibility trial to evaluate recruitment and retention by patient and clinician willingness of randomization; rates of withdrawal, crossover and attrition; and feasibility of outcome data collection from routine primary and secondary care data.