Aims. An evidence-based radiographic Decision Aid for meniscal-bearing unicompartmental knee arthroplasty (UKA) has been developed and this study investigates its performance at an independent centre. Patients and Methods. Pre-operative radiographs, including stress views, from a consecutive cohort of 550 knees undergoing arthroplasty (UKA or total knee arthroplasty; TKA) by a single-surgeon were assessed. Suitability for UKA was determined using the Decision Aid, with the assessor blinded to treatment received, and compared with actual treatment received, which was determined by an experienced UKA surgeon based on history, examination, radiographic assessment including stress radiographs, and intra-operative assessment in line with the recommended indications as described in the literature. Results. The sensitivity and specificity of the Decision Aid was 92% and 88%, respectively. Excluding knees where a clear pre-operative plan was made to perform TKA, i.e. patient request, the sensitivity was 93% and specificity 96%. The false-positive rate was low (2.4%) with all affected patients readily identifiable during joint inspection at surgery. In patients meeting Decision Aid criteria and receiving UKA, the five-year survival was 99% (95% confidence intervals (CI) 97 to 100). The false negatives (3.5%), who received UKA but did not meet the criteria, had significantly worse functional outcomes (flexion p < 0.001, American Knee Society Score - Functional p < 0.001, University of California Los Angeles score p = 0.04), and lower implant survival of 93.1% (95% CI 77.6 to 100). Conclusion. The radiographic Decision Aid safely and reliably identifies appropriate patients for meniscal-bearing UKA and achieves good results in this population. The widespread use of the Decision Aid should improve the results of UKA. Cite this article: Bone Joint J 2016;98-B(10 Suppl B):3–10

As arthroplasty demand grows worldwide, the need for a novel cost-effective treatment option for articular cartilage (AC) defects tailored to individual patients has never been greater. 3D bioprinting can deposit patient cells and other biomaterials in user-defined patterns to build tissue constructs from the “bottom-up,” potentially offering a new treatment for AC defects. The aim of this research was to create bioinks that can be injected or 3D bioprinted to aid osteochondral defect repair using human cells. Novel composite bioinks were created by mixing different ratios of methacrylated alginate (AlgMA) with methacrylated gelatin (GelMA). Chondrocytes or mesenchymal stem cells (MSCs) were then encapsulated in the bioinks and 3D bioprinted using a custom-built extrusion bioprinter. UV and double-ionic (BaCl2 and CaCl2) crosslinking was deployed following bioprinting to strengthen bioink stability in culture. Chondrocyte and MSC spheroids were also produced via 3D culture and then bioprinted to accelerate cell growth and development of ECM in bioprinted constructs. Excellent viability of chondrocytes and MSCs was seen following bioprinting (>95%) and maintained in culture over 28 days, with accelerated cell growth seen with inclusion of MSC or chondrocyte spheroids in bioinks (p<0.05). Bioprinted 10mm diameter constructs maintained shape in culture over 28 days, whilst construct degradation rates and mechanical properties were improved with addition of AlgMA (p<0.05). Composite bioinks were also injected into in vitro osteochondral defects (OCDs) and crosslinked in situ, with maintained cell viability and repair of osteochondral defects seen over a 14-day period. In conclusion we developed novel composite AlgMA/GelMA bioinks that can be triple-crosslinked, facilitating dense chondrocyte and MSC growth in constructs following 3D bioprinting. The bioink can be injected or 3D bioprinted to successfully repair in vitro OCDs, offering hope for a new approach to treating AC defects

As arthroplasty demand grows worldwide, the need for a novel cost-effective treatment option for articular cartilage (AC) defects tailored to individual patients has never been greater. 3D bioprinting can deposit patient cells and other biomaterials in user-defined patterns to build tissue constructs from the “bottom-up,” potentially offering a new treatment for AC defects. The aim of this research was to create bioinks that can be injected or 3D bioprinted to aid osteochondral defect repair using human cells. Novel composite bioinks were created by mixing different ratios of methacrylated alginate (AlgMA) with methacrylated gelatin (GelMA). Chondrocytes or mesenchymal stem cells (MSCs) were then encapsulated in the bioinks and 3D bioprinted using a custom-built extrusion bioprinter. UV and double-ionic (BaCl2 and CaCl2) crosslinking was deployed following bioprinting to strengthen bioink stability in culture. Chondrocyte and MSC spheroids were also bioprinted to accelerate cell growth and development of ECM in bioprinted constructs. Excellent viability of chondrocytes and MSCs was seen following bioprinting (>95%) and maintained in culture over 28 days, with accelerated cell growth seen with inclusion of MSC or chondrocyte spheroids in bioinks (p<0.05). Bioprinted 10mm diameter constructs maintained shape in culture over 28 days, whilst construct degradation rates and mechanical properties were improved with addition of AlgMA (p<0.05). Composite bioinks were also injected into in vitro osteochondral defects (OCDs) and crosslinked in situ, with maintained cell viability and repair of osteochondral defects seen over a 14-day period. In conclusion we developed novel composite AlgMA/GelMA bioinks that can be triple-crosslinked, facilitating dense chondrocyte and MSC growth in constructs following 3D bioprinting. The bioink can be injected or 3D bioprinted to successfully repair in vitro OCDs, offering hope for a new approach to treating AC defects

OpenPredictor, a machine learning-enabled clinical decision aid, has been developed to manage backlogs in elective surgeries. It aims to optimise the use of high volume, low complexity surgical pathways by accurately stratifying patient risk, thereby facilitating the allocation of patients to the most suitable surgical sites. The tool augments elective surgical pathways by providing automated secondary opinions for perioperative risk assessments, enhancing decision-making. Its primary application is in elective sites utilising lighter pre-assessment methods, identifying patients with minimal complication risks and those high-risk individuals who may benefit from early pre-assessment. The Phase 1 clinical evaluation of OpenPredictor entailed a prospective analysis of 156 patient records from elective hip and knee joint replacement surgeries. Using a polynomial logistic regression model, patients were categorised into high, moderate, and low-risk groups. This categorisation incorporated data from various sources, including patient demographics, co-morbidities, blood tests, and overall health status. In identifying patients at risk of postoperative complications, OpenPredictor demonstrated parity with consultant-led preoperative assessments. It accurately flagged 70% of patients who later experienced complications as moderate or high risk. The tool's efficiency in risk prediction was evidenced by its balanced accuracy (75.6%), sensitivity (70% with a 95% confidence interval of 62.05% to 76.91%), and a high negative predictive value (96.7%). OpenPredictor presents a scalable and consistent solution for managing elective surgery pathways, comparable in performance to secondary consultant opinions. Its integration into pre-assessment workflows assists in efficient patient categorisation, reduces late surgery cancellations, and optimises resource allocation. The Phase 1 evaluation of OpenPredictor underscores its potential for broader clinical application and highlights the need for ongoing data refinement and system integration to enhance its performance

Prophylactic treatment is advised for metastatic bone disease patients with a high risk of fracture. Clinicians face the task of identifying these patients with high fracture risk and determining the optimal surgical treatment method. Subject-specific finite element (FE) models can aid in this decision process by predicting the mechanical effect of surgical treatment. In this study, we specifically evaluated the potential of FE models to simulate femoroplasty, as uncertainty remains whether this prophylactic procedure provides sufficient mechanical strengthening to the weight-bearing femur. In eight pairs of human cadaveric femurs artificial metastatic lesions were created. In each pair, an identical defect was milled in the left and right femur. Four pairs received a spherical lesion in the neck and the other four an ellipsoidal lesion in the intertrochanteric region, each at the medial, superior/lateral, anterior and posterior side, respectively. One femur of each pair was augmented with polymethylmethacrylate (5–10 ml), while the contralateral femur was left untreated. CT scans were made at three different time points: from the unaffected intact femurs, the defect femurs with lesion and the augmented femurs. Bone strength was measured by mechanical testing until failure in eight defect and eight augmented femurs. Nonlinear CT-based FE models were developed and validated against the experimentally measured bone strength. Subsequently, the validated FE model was applied to the available CT scans for the three different cases: intact (16 scans), defect (16) and augmented (8). The FE predicted strength was compared for the three different cases. The FE models predicted the experimental bone strength with a strong correspondence, both for the defect (R. 2. = 0.97, RMSE= 0.75 kN) and the augmented femurs (R. 2. = 0.90, RMSE = 0.98 kN). Although all lesions had a “moderate” to “high” risk for fracture according to the Mirels’ scoring system (score 7 or 8), three defect femurs did not fracture through the lesion (intertrochanteric anterior, lateral and posterior), indicating that these lesions did not act as a critical weak spot. In accordance with the experimental findings, the FE models indicated almost no reduction in strength between the intact and defect state for these femurs (0.02 ± 0.1%). For the remaining “critical” lesions, bone strength was reduced with 15.7% (± 14.9%) on average. The largest reduction was observed for lesions on the medial side (up to 43.1%). For the femurs with critical lesions, augmentation increased bone strength with 29.5% (± 29.7%) as compared to the defect cases, reaching strength values that were 2.5% (± 3.7%) higher than the intact bone strength. Our findings demonstrate that FE models can accurately predict the experimental bone strength before and after augmentation, thereby enabling to quantify the mechanical benefit of femoroplasty. This way FE models could aid in identifying suitable patients for whom femoroplasty provides sufficient increase in strength. For all lesions evaluated in this study, femoroplasty effectively restored the initial bone strength. Yet, additional studies on larger datasets with a wide variation of lesion types are required to confirm these results

Introduction. The application of artificial intelligence (A.I) using patient reported outcomes (PROs) to predict benefits, risks, benefits and likelihood of improvement following surgery presents a new frontier in shared decision-making. The purpose of this study was to assess the impact of an A.I-enabled decision aid versus patient education alone on decision quality in patients with knee OA considering total knee replacement (TKR). Secondarily we assess impact on shared decision-making, patient satisfaction, functional outcomes, consultation time, TKR rates and treatment concordance. Methods. We performed a randomized controlled trial involving 130 new adult patients with OA-related knee pain. Patients were randomized to receive the decision aid (intervention group, n=65) or educational material only (control group, n=65) along with usual care. Both cohorts completed patient surveys including PROs at baseline and between 6–12 weeks following initial evaluation or TKR. Statistical analysis included linear mixed effect models, Mann-Whitney U tests to assess for differences between groups and Fisher's exact test to evaluate variations in surgical rates and treatment concordance. Results. The intervention group showed greater decision quality (K-DQI, Mean difference = 20%, p<0.0001), collaboration in decision-making (CollaboRATE, 12% (intervention group), 47% (control group) below median, p<0.0001), satisfaction with consultations (NRS-C, 14% (intervention group), 33% (control group) below median, p=0.008), improvement in functional outcomes from baseline up to 12 week follow-up (KOOSJR, 4.9 pts higher (intervention group), p=0.029) without significantly impacting consultation time. No differences were observed in TKR rates or treatment concordance. Conclusion. A.I-enabled decision aids incorporating PROs in predictive algorithms can improve decision quality, level of shared decision-making, satisfaction with patient-provider consultations, and functional outcomes, without extending consultation times. The combination of advanced predictive technologies and patient reported data to forecast surgical outcomes presents a paradigm shift in shared decision making and the delivery of high value care for patients with knee OA

Aim. Left sided hip fractures are more common but no obvious cause has been identified. Left handedness has previously been associated with an increased risk of fracture for a number of sites but to the best of our knowledge no association between handedness and hip fracture has previously been reported. Methods. 2 separate 6-month prospective reviews of hip fracture patients aged over 65 years-of-age were conducted at 2 different hospitals. Handedness was dete2rmined at the time of admission. The second review focused on the use of walking aids. Patients with a previous cerebrovascular accident, neurological condition or contralateral hip prosthesis were excluded due to increased balance problems and falls risk. Results. Hand dominance was recorded for 339 patients; 304 right and 35 left. 91 patients were excluded. Of the remaining 248 patients more than twice as many (2.06 times) fractured their hip on the side of their non-dominant hand. For left handed individuals this increased to 4.6 times. Walking aid use was recorded for 102 patients. For patients using no walking aids, a Zimmer frame or 2 walking sticks; equal numbers of patients sustained right and left hip fractures. While 97.7% of patients using 1 walking stick did so in their dominant hand, sustaining 84% contralateral hip fractures. Conclusions. The direction in which people fall and the causes of hip fractures are clearly multi-factorial. However there is a clear association between hand dominance and the side of hip fracture, particularly in left handed individuals. Walking aids also play a role with 97.7% of patients using a walking stick in their dominant hand resulting in 84% contralateral hip fractures. By being aware of this association it may be possible to target both patient education and physiotherapy potentially reducing the number of patient falls and associated hip fractures

As arthroplasty demand grows worldwide, the need for a novel cost-effective treatment option for articular cartilage (AC) defects tailored to individual patients has never been greater. 3D bioprinting can deposit patient cells and other biomaterials in user-defined patterns to build tissue constructs from the “bottom-up,” potentially offering a new treatment for AC defects.

Novel composite bioinks were created by mixing different ratios of methacrylated alginate (AlgMA) with methacrylated gelatin (GelMA) and collagen. Chondrocytes and mesenchymal stem cells (MSCs) were then encapsulated in the bioinks and 3D bioprinted using a custom-built extrusion bioprinter. UV and double-ionic (BaCl2 and CaCl2) crosslinking was deployed following bioprinting to strengthen bioink stability in culture. Chondrocyte and MSC spheroids were also bioprinted to accelerate cell growth and development of ECM in bioprinted constructs.

Excellent viability of chondrocytes and MSCs was seen following bioprinting (>95%) and maintained in culture, with accelerated cell growth seen with inclusion of cell spheroids in bioinks (p<0.05). Bioprinted 10mm diameter constructs maintained shape in culture over 28 days, whilst construct degradation rates and mechanical properties were improved with addition of AlgMA (p<0.05). Composite bioinks were also injected into in vitro osteochondral defects and crosslinked in situ, with maintained cell viability and repair of osteochondral defects seen over a 14-day period.

In conclusion, we developed novel composite bioinks that can be triple-crosslinked, facilitating successful chondrocyte and MSC growth in 3D bioprinted scaffolds and in vitro repair of an osteochondral defect model. This offers hope for a new approach to treating AC defects.

Aims

The modified Glasgow Prognostic Score (mGPS) uses preoperative CRP and albumin to calculate a score from 0 to 2 (2 being associated with poor outcomes). mGPS is validated in multiple carcinomas. To date, its use in soft-tissue sarcoma (STS) is limited, with only small cohorts reporting that increased mGPS scores correlates with decreased survival in STS patients.

Cite this article: Bone Joint Res 2023;12(9):598–600.

Introduction

Treatment of non-union in open tibial fractures Gustilo-Anderson(GA)-3A/3B fractures remains a challenging problem. Most of these can be dealt using treatment methods that requires excision of the non-union followed by bone grafting, masquelet technique, or acute shortening. Circular fixators with closed distraction or bone transport also remains a useful option. However, sometimes due to patient specific factors these cannot be used. Recently antibiotic loaded bone substitutes have been increasingly used for repairing infected non-unions. They provide local antibiotic delivery, fill dead space, and act as a bone conductive implant, which is resorted at the end of a few months. We aimed to assess the outcome of percutaneous injection of bone substitute while treating non-union of complex open tibial fractures.

Acute osteoporotic vertebral compression fractures (VCFs) are frequently misdiagnosed as there is often no history of preceding trauma. VCFs not only cause back pain, but can also result in a loss of function, spinal deformity and increased mortality. Cement augmentation has been shown to effectively treat these fractures. It is impossible to diagnose an acute fracture on plain x-ray and therefore identify those likely to benefit from this treatment. The definitive investigation to determine the presence of an acute fracture is a MR scan, but this is a limited resource. The aim of this paper is to evaluate 2 new clinical signs which we believe aid in the diagnosis of an acute VCF: firstly closed fist percussion at the level of an acute VCF resulting in a severe, sharp fracture pain, and secondly the inability of a patient to lie supine. This was a prospective study of 78 patients with suspected acute VCFs. 48/78 had an acute fracture on MR. 42/45 patients who were positive for closed fist percussion, had an acute fracture on their MR scan. There were 6 patients who were negative for closed fist percussion who had an acute fracture (sensitivity 87.5%, specificity 90%). 39/41 patients who were positive for the supine sign had an acute fracture on their MR scan. There were 9 patients who were comfortably able to lay supine who had an acute fracture (sensitivity 81.25%, specificity 93.33%). Either a positive closed fist percussion sign or a positive supine sign is a reliable indicator of the presence of an acute VCF. By incorporating these signs into our routine clinical assessment we are better able to predict which patients have an acute fracture, and therefore decide which patients need a MR scan

Purpose of study The purpose of this study was to present the anterior femoral cortical line (AFCL) as a new anatomical landmark to aid the assessment of intra-operative femoral component rotation. The AFCL was compared with an established axis (the anteroposterior (AP) axis or Whiteside’s line) in both a cadaveric and clinical study. Methods Two points indicating the AP axis were identified and marked on 50 normal cadaveric femora. The AFCL was identified and marked with a rigid wire secured on the surface and the distal femur was photographed. A perpendicular to the AP axis was drawn on each image and the angle between this line and the AFCL was measured. 68 consecutive patients undergoing total knee arthroplasty for osteoarthritis of the knee were included in the clinical part of the study. After a routine exposure the AP axis was marked on each distal femur. The AFCL was identified and the anterior cortical cut was made parallel to this line. The angle between this cortical cut and the perpendicular to the AP axis was measured with a sterile goniometer. Results In the cadaveric study the AFCL was a mean 7.0 degrees internally rotated to the AP axis (SD = 5.1 degrees). In the clinical study in 8 patients it was impossible to draw the AP axis because of dysplasia or destruction of the trochlea by osteoarthrosis. In the remainder the mean difference between the anterior femoral cortical line and the AP axis was 1.5 degrees internally rotated (SD = 1.9 degrees) . Conclusion The anterior femoral cortical line has been shown in this study to be a useful clinical axis for assessing rotation of the femoral component and is without some of the disadvantages associated with other landmarks

We report the results of six trauma and orthopaedic projects to Kenya in the last three years. The aims are to deliver both a trauma service and teaching within two hospitals; one a district hospital near Mount Kenya in Nanyuki, the other the largest public hospital in Kenya in Mombasa. The Kenya Orthopaedic Project team consists of a wide range of multidisciplinary professionals that allows the experience to be shared across those specialties. A follow-up clinic is held three months after each mission to review the patients. To our knowledge there are no reported outcomes in the literature for similar projects.

A total of 211 operations have been performed and 400 patients seen during the projects. Most cases were fractures of the lower limb; we have been able to follow up 163 patients (77%) who underwent surgical treatment. We reflect on the results so far and discuss potential improvements for future missions.

Introduction: Recently frameless stereotaxy has been introduced to assist with the spinal instrumentation. The mobility of individual vertebra however limits its accuracy and ease of use. The authors have developed a novel method of spinal stereotaxy using exact plastic copies of the spine manufactured using biomodelling technology.

Methods: Fifteen patients with complex spinal disorders requiring instrumentation were recruited. A 3D CT scan of their spine was performed and the data were transferred via DICOM network to a computer workstation. ANATOMICS BIOBUILD software was used to generate the code required to manufacture exact acrylate biomodels of each spine using rapid prototyping. The biomodels were used to obtain informed consent from patients and simulate surgery. Simulation was performed using a standard power drill to place trajectory pins in the appropriate pedicles. Acrylate drill guides were manufactured using the biomodels as templates. The biomodels and templates were sterilised and used intra-operatively to assist with the placement of the instrumentation.

Results: The biomodels were found to be highly accurate and of great assistance in the planning and execution of the surgery. The ability to drill optimum screw trajectories in the biomodel and then accurately replicate the trajectory was judged especially helpful. Accurate screw placement was confirmed with post-operative CT scanning. The design of the first two templates was suboptimal as the contact surface area was too great and complex. Approximately 20 minutes was spent pre-operatively preparing each biomodel and template. Operating time was reduced, as less reliance on intra-operative X-ray was necessary. Minimal invasive surgery was greatly facilitated in planning and execution. Patients stated that the biomodels improved informed consent.

Conclusion: Biomodel spinal stereotaxy is a simple and accurate technique which may have advantages over frameless stereotaxy.

The screw fastening torque applied during bone fracture fixation has a decisive influence on subsequent bone healing. Insufficient screw tightness can result in device/construct instability; conversely, excessive torques risk damaging the bone causing premature fixation failure. This effect is even more prominent in osteoporotic bone, a condition associated annually with almost 9 million fractures worldwide. During fracture fixation, screw tightening torque is applied using subjective feel. This approach may not be optimal for patient”s recovery, increasing risk of fixation failure, particularly in osteoporotic bone, and potentially require revision surgical interventions.

Besides bone density, various factors influence the performance of screw fixation. These factors include bone geometry, cortical thickness and time-dependant relaxation behaviour of the bone. If the influence of screw fastening torque on the bone and relationships between these factors was better understood, the surgical technique could be optimised to reduce the risk of complications.

Within this study, we developed an axisymmetric finite element (FE) model of bone screw tightening incorporating viscoelastic behaviour of the cortical bone such as creep and stress relaxation. The model anticipated time-dependent behaviour of the bone for different bone thickness and density after a typical bone fixation screw had been inserted. The idealised model has been developed based on CT scans of bones with varying densities and inserted screws. The model was validated through a series of experiments involving bovine tibiae (4–5 months) to evaluate the evolution of surface strains with time (Ncorr v1.2). Stress distribution was assessed in photoelastic experiments using acrylic analogues. Relaxation tests have been performed in aqueous environment for up to 48 hours to ensure the relaxation would be complete. The creep behaviour (maximum principal strain) was compared against computational predictions. Our early simulations predicted relaxation strains on the surface of the bone to be 1.1% within 24 hours comparing favourably to 1.3% measured experimentally. Stress distribution patterns were in agreement with photoelastic results.

Using experimentally derived viscoelastic properties, the model has the potential to predict creep and stress relaxation patterns after screw insertion with different fastening torques for bones with varying density and geometry. We aim to develop this into a planning tool providing guidance to surgeons for optimal tightening when using screw fixation, particularly in reduced quality bone.

1. A diagnostic procedure is described which is specific for fat embolism. It allows identification of the pathological fat globules On a stained slide.

2. The amount of pathological fat can be estimated by comparing the serum triglyceride levels before and after filtration.

3. The method is simple, reproducible and inexpensive.

1. Arthrodesis of the hip is satisfactory provided a good range of knee flexion is preserved.

2. The hip is best arthrodesed in its deformed position, and the deformity corrected by a high femoral osteotomy. Knee range can readily be retained by treating the patient on traction for the first six weeks instead of using plaster.

3. Thirty-three arthrodeses were attempted without osteotomy. Only thirteen were satisfactory. Even our best method without osteotomy gave sound fusion in only seven out of ten cases.

4. In a series of twenty-three unselected cases in which osteotomy was performed in addition to other methods, fusion occurred in twenty-two.