Aims. The Wrightington classification system of fracture-dislocations of the elbow divides these injuries into six subtypes depending on the involvement of the coronoid and the radial head. The aim of this study was to assess the reliability and reproducibility of this classification system. Methods. This was a blinded study using radiographs and CT scans of 48 consecutive patients managed according to the Wrightington classification system between 2010 and 2018. Four trauma and orthopaedic consultants, two post CCT fellows, and one speciality registrar based in the UK classified the injuries. The seven observers reviewed preoperative radiographs and CT scans twice, with a minimum four-week interval. Radiographs and CT scans were reviewed separately. Inter- and intraobserver reliability were calculated using Fleiss and Cohen kappa coefficients. The Landis and Koch criteria were used to interpret the strength of the kappa values. Validity was assessed by calculating the percentage agreement against intraoperative findings. Results. Of the 48 patients, three (6%) had type A injury, 11 (23%) type B, 16 (33%) type B+, 16 (33%) Type C, two (4%) type D+, and none had a type D injury. All 48 patients had anteroposterior (AP) and lateral radiographs, 44 had 2D CT scans, and 39 had 3D reconstructions. The interobserver reliability kappa value was 0.52 for radiographs, 0.71 for 2D CT scans, and 0.73 for a combination of 2D and 3D reconstruction CT scans. The median intraobserver reliability was 0.75 (interquartile range (IQR) 0.62 to 0.79) for radiographs, 0.77 (IQR 0.73 to 0.94) for 2D CT scans, and 0.89 (IQR 0.77 to 0.93) for the combination of 2D and 3D reconstruction. Validity analysis showed that accuracy significantly improved when using CT scans (p = 0.018 and p = 0.028 respectively). Conclusion. The Wrightington classification system is a reliable and valid method of classifying fracture-dislocations of the elbow. CT scans are significantly more accurate than radiographs when identifying the pattern of injury, with good intra- and interobserver reproducibility. Cite this article: Bone Joint J 2020;102-B(8):1041–1047

Aims. It has been hypothesized that proximal radial neck resorption (PRNR) following press-fit radial head arthroplasty (RHA) is due to stress-shielding. We compared two different press-fit stems by means of radiographs to investigate whether the shape and size of the stems are correlated with the degree of PRNR. Methods. The radiographs of 52 RHAs were analyzed both at 14 days postoperatively and after two years. A cylindrical stem and a conical stem were implanted in 22 patients (group 1) and 30 patients (group 2), respectively. The PRNR was measured in the four quadrants of the radial neck and the degree of stem filling was calculated by analyzing the ratio between the prosthetic stem diameter (PSD) and the medullary canal diameter (MCD) at the proximal portion of the stem (level A), halfway along the stem length (level B), and distally at the stem tip (level C). Results. Overall, 50 of the 52 patients displayed PRNR. The mean PRNR observed was 3.9 mm (0 to 7.4). The degree of endomedullary stem filling at levels A, B, and C was 96%, 90%, and 68% in group 1, and 96%, 72%, and 57%, in group 2, with differences being significant at levels B (p < 0.001) and C (p < 0.001). No significant correlations emerged between the severity of PRNR and the three stem/canal ratios either within each group or between the groups. Conclusion. PRNR in press-fit RHA appears to be independent of the shape and size of the stems. Other causes besides stem design should be investigated to explain completely this phenomenon. Cite this article: Bone Joint J 2021;103-B(3):530–535

Aims. Perthes’ disease (PD) often results in femoral head deformity and leg length discrepancy (LLD). Our objective was to analyze femoral morphology in PD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalization on proximal and subtrochanteric femoral lengths. Methods. All patients treated for PD in our institution between January 2013 and June 2020 were reviewed retrospectively. Patients with unilateral PD, LLD of ≥ 5 mm, and long-leg standing radiographs at skeletal maturity were included. Total leg length, femoral and tibial length, articulotrochanteric distance (ATD), and subtrochanteric femoral length were compared between PD side and the unaffected side. Furthermore, we compared leg length measurements between patients who did and who did not have a contralateral epiphysiodesis. Results. Overall, 79 patients were included, of whom 21 underwent contralateral epiphysiodesis for leg length correction. In the complete cohort, the mean LLD was 1.8 cm (95% confidence interval (CI) 1.5 to 2.0), mean ATD difference was 1.8 cm (95% CI -2.1 to -1.9), and mean subtrochanteric difference was -0.2 cm (95% CI -0.4 to 0.1). In the epiphysiodesis group, the mean LLD before epiphysiodesis was 2.7 cm (95% CI 1.3 to 3.4) and 1.3 cm (95% CI -0.5 to 3.8) at skeletal maturity. In the nonepiphysiodesis group the mean LLD was 2.0 cm (95% CI 0.5 to 5.1; p = 0.016). The subtrochanteric region on the PD side was significantly longer at skeletal maturity in the epiphysiodesis group compared to the nonepiphysiodesis group (-1.0 cm (95% CI -2.4 to 0.6) vs 0.1 cm (95% CI -1.0 to 2.1); p < 0.001). Conclusion. This study demonstrates that LLD after PD originates from the proximal segment only. In patients who had contralateral epiphysiodesis to balance leg length, this is achieved by creating a difference in subtrochanteric length. Arthroplasty surgeons need to be aware that shortening of the proximal femur segment in PD patients may be misleading, as the ipsilateral subtrochanteric length in these patients can be longer. Therefore, we strongly advise long-leg standing films for THA planning in PD patients in order to avoid inadvertently lengthening the limb. Cite this article: Bone Joint J 2021;103-B(11):1736–1741

Aims. The incidence of atypical femoral fractures (AFFs) continues to increase. However, there are currently few long-term studies on the complications of AFFs and factors affecting them. Therefore, we attempted to investigate the outcomes, complications, and risk factors for complication through mid-term follow-up of more than three years. Methods. From January 2003 to January 2016, 305 patients who underwent surgery for AFFs at six hospitals were enrolled. After exclusion, a total of 147 patients were included with a mean age of 71.6 years (48 to 89) and 146 of whom were female. We retrospectively evaluated medical records, and reviewed radiographs to investigate the fracture site, femur bowing angle, presence of delayed union or nonunion, contralateral AFFs, and peri-implant fracture. A statistical analysis was performed to identify the significance of associated factors. Results. The mean follow-up period was 70.2 months (36 to 191). There were 146 AFFs (99.3%) in female patients and the mean age was 71.6 years (48 to 89). The AFFs were located in the subtrochanter and shaft in 52 cases (35.4%) and 95 (64.6%), respectively. The preoperative mean anterior/lateral femoral bowing angles were 10.5° (SD 5.7°)/6.1° (SD 6.2°). The postoperative mean anterior/lateral bowing values were changed by 8.7° (SD 5.4°)/4.6° (SD 5.9°). Bisphosphonates had been used contemporarily in 115 AFFs (78.2%) for a mean of 52.4 months (1 to 204; SD 45.5) preoperatively. Nailing was performed in 133 AFFs (90.5%), and union was obtained at a mean of 23.6 weeks (7 to 85). Delayed union occurred in 41 (27.9%), and nonunion occurred in 13 (8.8%). Contralateral AFF occurred in 79 patients (53.7%), and the use of a bisphosphonate significantly influenced the occurrence of contralateral AFFs (p = 0.019). Peri-implant fractures occurred in a total of 13 patients (8.8%), and a significant increase was observed in cases with plating (p = 0.021) and high grade of postoperative anterolateral bowing (p = 0.044). Conclusion. The use of a bisphosphonate was found to be a risk factor for contralateral AFF, and high-grade postoperative anterolateral bowing and plate fixation significantly increased the occurrence of peri-implant fractures. Long-term follow-up studies on the bilaterality of AFFs and peri-implant fractures are warranted. Cite this article: Bone Joint J 2021;103-B(11):1648–1655

Aims. Pelvic tilt (PT) can significantly change the functional orientation of the acetabular component and may differ markedly between patients undergoing total hip arthroplasty (THA). Patients with stiff spines who have little change in PT are considered at high risk for instability following THA. Femoral component position also contributes to the limits of impingement-free range of motion (ROM), but has been less studied. Little is known about the impact of combined anteversion on risk of impingement with changing pelvic position. Methods. We used a virtual hip ROM (vROM) tool to investigate whether there is an ideal functional combined anteversion for reduced risk of hip impingement. We collected PT information from functional lateral radiographs (standing and sitting) and a supine CT scan, which was then input into the vROM tool. We developed a novel vROM scoring system, considering both seated flexion and standing extension manoeuvres, to quantify whether hips had limited ROM and then correlated the vROM score to component position. Results. The vast majority of THA planned with standing combined anteversion between 30° to 50° and sitting combined anteversion between 45° to 65° had a vROM score > 99%, while the majority of vROM scores less than 99% were outside of this zone. The range of PT in supine, standing, and sitting positions varied widely between patients. Patients who had little change in PT from standing to sitting positions had decreased hip vROM. Conclusion. It has been shown previously that an individual’s unique spinopelvic alignment influences functional cup anteversion. But functional combined anteversion, which also considers stem position, should be used to identify an ideal THA position for impingement-free ROM. We found a functional combined anteversion zone for THA that may be used moving forward to place total hip components. Cite this article: Bone Jt Open 2021;2(10):834–841

Aims. The aim of this study was to evaluate the ability of a machine-learning algorithm to diagnose prosthetic loosening from preoperative radiographs and to investigate the inputs that might improve its performance. Methods. A group of 697 patients underwent a first-time revision of a total hip (THA) or total knee arthroplasty (TKA) at our institution between 2012 and 2018. Preoperative anteroposterior (AP) and lateral radiographs, and historical and comorbidity information were collected from their electronic records. Each patient was defined as having loose or fixed components based on the operation notes. We trained a series of convolutional neural network (CNN) models to predict a diagnosis of loosening at the time of surgery from the preoperative radiographs. We then added historical data about the patients to the best performing model to create a final model and tested it on an independent dataset. Results. The convolutional neural network we built performed well when detecting loosening from radiographs alone. The first model built de novo with only the radiological image as input had an accuracy of 70%. The final model, which was built by fine-tuning a publicly available model named DenseNet, combining the AP and lateral radiographs, and incorporating information from the patient’s history, had an accuracy, sensitivity, and specificity of 88.3%, 70.2%, and 95.6% on the independent test dataset. It performed better for cases of revision THA with an accuracy of 90.1%, than for cases of revision TKA with an accuracy of 85.8%. Conclusion. This study showed that machine learning can detect prosthetic loosening from radiographs. Its accuracy is enhanced when using highly trained public algorithms, and when adding clinical data to the algorithm. While this algorithm may not be sufficient in its present state of development as a standalone metric of loosening, it is currently a useful augment for clinical decision making. Cite this article: Bone Joint J 2020;102-B(6 Supple A):101–106

Aims. We have previously reported cryoablation-assisted joint-sparing surgery for osteosarcoma with epiphyseal involvement. However, it is not clear whether this is a comparable alternative to conventional joint arthroplasty in terms of oncological and functional outcomes. Methods. A total of 22 patients who had localized osteosarcoma with epiphyseal involvement around the knee and underwent limb salvage surgery were allocated to joint preservation (JP) group and joint arthroplasty (JA) group. Subjects were followed with radiographs, Musculoskeletal Tumor Society (MSTS) score, and clinical evaluations at one, three, and five years postoperatively. Results. Patients in both groups (ten in JP and 12 in JA) did not differ in local recurrence (p ≥ 0.999) and occurrence of metastases (p ≥ 0.999). Overall survival was similar in both groups (p = 0.858). Patients in the JP group had less range of motion (ROM) of the knee (p < 0.001) and lower MSTS scores (p = 0.010) compared with those of the JA group only at one year postoperatively. There was no difference between groups either at three years for ROM (p = 0.185) and MSTS score (p = 0.678) or at five years for ROM (p = 0.687) and MSTS score (p = 0.536), postoperatively. Patients in the JA group tended to have more complications (p = 0.074). Survival of primary reconstruction in the JP group was better than that of the JA group (p = 0.030). Conclusion. Cryoablation-aided joint-sparing surgery offers native joint preservation with comparable functional recovery and more durable reconstruction without jeopardizing oncological outcomes compared with conventional limb salvage surgery. Cite this article: Bone Joint J 2021;103-B(8):1421–1427

Aims. This aim of this study was to assess the reliability and validity of the Unified Classification System (UCS) for postoperative periprosthetic femoral fractures (PFFs) around cemented polished taper-slip (PTS) stems. Methods. Radiographs of 71 patients with a PFF admitted consecutively at two centres between 25 February 2012 and 19 May 2020 were collated by an independent investigator. Six observers (three hip consultants and three trainees) were familiarized with the UCS. Each PFF was classified on two separate occasions, with a mean time between assessments of 22.7 days (16 to 29). Interobserver reliability for more than two observers was assessed using percentage agreement and Fleiss’ kappa statistic. Intraobserver reliability between two observers was calculated with Cohen kappa statistic. Validity was tested on surgically managed UCS type B PFFs where stem stability was documented in operation notes (n = 50). Validity was assessed using percentage agreement and Cohen kappa statistic between radiological assessment and intraoperative findings. Kappa statistics were interpreted using Landis and Koch criteria. All six observers were blinded to operation notes and postoperative radiographs. Results. Interobserver reliability percentage agreement was 58.5% and the overall kappa value was 0.442 (moderate agreement). Lowest kappa values were seen for type B fractures (0.095 to 0.360). The mean intraobserver reliability kappa value was 0.672 (0.447 to 0.867), indicating substantial agreement. Validity percentage agreement was 65.7% and the mean kappa value was 0.300 (0.160 to 0.4400) indicating only fair agreement. Conclusion. This study demonstrates that the UCS is unsatisfactory for the classification of PFFs around PTS stems, and that it has considerably lower reliability and validity than previously described for other stem types. Radiological PTS stem loosening in the presence of PFF is poorly defined and formal intraoperative testing of stem stability is recommended. Cite this article: Bone Joint J 2021;103-B(8):1339–1344

Aims. Appropriate acetabular component placement has been proposed for prevention of postoperative dislocation in total hip arthroplasty (THA). Manual placements often cause outliers in spite of attempts to insert the component within the intended safe zone; therefore, some surgeons routinely evaluate intraoperative pelvic radiographs to exclude excessive acetabular component malposition. However, their evaluation is often ambiguous in case of the tilted or rotated pelvic position. The purpose of this study was to develop the computational analysis to digitalize the acetabular component orientation regardless of the pelvic tilt or rotation. Methods. Intraoperative pelvic radiographs of 50 patients who underwent THA were collected retrospectively. The 3D pelvic bone model and the acetabular component were image-matched to the intraoperative pelvic radiograph. The radiological anteversion (RA) and radiological inclination (RI) of the acetabular component were calculated and those measurement errors from the postoperative CT data were compared relative to those of the 2D measurements. In addition, the intra- and interobserver differences of the image-matching analysis were evaluated. Results. Mean measurement errors of the image-matching analyses were significantly small (2.5° (SD 1.4°) and 0.1° (SD 0.9°) in the RA and RI, respectively) relative to those of the 2D measurements. Intra- and interobserver differences were similarly small from the clinical perspective. Conclusion. We have developed a computational analysis of acetabular component orientation using an image-matching technique with small measurement errors compared to visual evaluations regardless of the pelvic tilt or rotation. Cite this article: Bone Joint Res 2020;9(7):360–367

Aims. The purpose of this study was to compare clinical results, long-term survival, and complication rates of stemless shoulder prosthesis with stemmed anatomical shoulder prostheses for treatment of osteoarthritis and to analyze radiological bone changes around the implants during follow-up. Methods. A total of 161 patients treated with either a stemmed or a stemless shoulder arthroplasty for primary osteoarthritis of the shoulder were evaluated with a mean follow-up of 118 months (102 to 158). The Constant score (CS), the Disabilities of the Arm, Shoulder and Hand (DASH) score, and active range of motion (ROM) were recorded. Radiological analysis for bone adaptations was performed by plain radiographs. A Kaplan-Meier survivorship analysis was calculated and complications were noted. Results. The ROM (p < 0.001), CS (p < 0.001), and DASH score (p < 0.001) showed significant improvements after shoulder arthroplasty for both implants. There were no differences between the groups treated with stemmed or stemless shoulder prosthesis with respect to the mean CS (79.2 (35 to 118) vs 74.4 (31 to 99); p = 0.519) and DASH scores (11.4 (8 to 29) vs 13.2 (7 to 23); p = 0.210). The ten-year unadjusted cumulative survival rate was 95.3% for the stemmed anatomical shoulder prosthesis and 91.5% for the stemless shoulder prosthesis and did not differ between the treatment groups (p = 0.251). The radiological evaluation of the humeral components in both groups did not show loosening of the humeral implant. The main reason for revision for each type of arthroplasties were complications related to the glenoid. Conclusion. The use of anatomical stemless shoulder prosthesis yielded good and reliable results and did not differ from anatomical stemmed shoulder prosthesis over a mean period of ten years. The differences in periprosthetic humeral bone adaptations between both implants have no clinical impact during the follow-up. Cite this article: Bone Joint J 2021;103-B(7):1292–1300

Aims. The aims of this study were to determine the change in the sagittal alignment of the pelvis and the associated impact on acetabular component position at one-year follow-up after total hip arthroplasty (THA). Methods. This study represents the one-year follow-up of a previous short-term study at our institution. Using the patient population from our prior study, the radiological pelvic ratio was assessed in 91 patients undergoing THA, of whom 50 were available for follow-up of at least one year (median 1.5; interquartile range (IQR) 1.1 to 2.0). Anteroposterior radiographs of the pelvis were obtained in the standing position preoperatively and at one year postoperatively. Pelvic ratio was defined as the ratio between the vertical distance from the inferior sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior SI joints. Apparent acetabular component position changes were determined from the change in pelvic ratio. A change of at least 5° was considered clinically meaningful. Results. Pelvic ratio decreased (posterior tilt) in 54.0% (27) of cases, did not change significantly in 34.0% (17) of cases, and increased (anterior tilt) in 12.0% (6) of cases when comparing preoperative to one-year postoperative radiographs. This would correspond with 5° to 10° of abduction error in 22.0% of cases and > 10° of error in 6.0%. Likewise, this would correspond with 5° to 10° of version error in 22.0% of cases and > 10° of error in 44.0%. Conclusion. Pelvic sagittal alignment is dynamic and variable after THA, and these changes persist to the one-year postoperative period, altering the orientation of the acetabular component. Surgeons who individualize the acetabular component placement based on preoperative functional radiographs should consider that the rotation of the pelvis (and thus the component version and inclination) changes one year postoperatively. Cite this article: Bone Joint J 2020;102-B(7 Supple B):47–51

Aims. To assess the proportion of patients with distal radius fractures (DRFs) who were managed nonoperatively during the COVID-19 pandemic in accordance with the British Orthopaedic Association BOAST COVID-19 guidelines, who would have otherwise been considered for an operative intervention. Methods. We retrospectively reviewed the radiographs and clinical notes of all patients with DRFs managed nonoperatively, following the publication of the BOAST COVID-19 guidelines on the management of urgent trauma between 26 March and 18 May 2020. Radiological parameters including radial height, radial inclination, intra-articular step-off, and volar tilt from post-reduction or post-application of cast radiographs were measured. The assumption was that if one radiological parameter exceeds the acceptable criteria, the patient would have been considered for an operative intervention in pre-COVID times. Results. Overall, 92 patients formed the cohort of this study with a mean age of 66 years (21 to 96); 84% (n = 77) were female and 16% (n = 15) were male. In total, 54% (n = 50) of patients met at least one radiological indication for operative intervention with a mean age of 68 years (21 to 96). Of these, 42% (n = 21) were aged < 65 years and 58% (29) were aged ≥ 65 years. Conclusion. More than half of all DRFs managed nonoperatively during the COVID-19 pandemic had at least one radiological indication to be considered for operative management pre-COVID. We anticipate a proportion of these cases will require corrective surgery in the future, which increases the load on corrective upper limb elective services. This should be accounted for when planning an exit strategy and the restart of elective surgery services. Cite this article: Bone Joint Open 2020;1-10:612–616

Aims. The aim of this study was to assess whether supine flexibility predicts the likelihood of curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment. Methods. This was a retrospective analysis of patients with AIS prescribed with an underarm brace between September 2008 to April 2013 and followed up until 18 years of age or required surgery. Patients with structural proximal curves that preclude underarm bracing, those who were lost to follow-up, and those who had poor compliance to bracing (<16 hours a day) were excluded. The major curve Cobb angle, curve type, and location were measured on the pre-brace standing posteroanterior (PA) radiograph, supine whole spine radiograph, initial in-brace standing PA radiograph, and the post-brace weaning standing PA radiograph. Validation of the previous in-brace Cobb angle regression model was performed. The outcome of curve progression post-bracing was tested using a logistic regression model. The supine flexibility cut-off for curve progression was analyzed with receiver operating characteristic curve. Results. A total of 586 patients with mean age of 12.6 years (SD 1.2) remained for analysis after exclusion. The baseline Cobb angle was similar for thoracic major curves (31.6° (SD 3.8°)) and lumbar major curves (30.3° (SD 3.7°)). Curve progression was more common in the thoracic curves than lumbar curves with mean final Cobb angles of 40.5° (SD 12.5°) and 31.8° (SD 9.8°) respectively. This dataset matched the prediction model for in-brace Cobb angle with less mean absolute error in thoracic curves (0.61) as compared to lumbar curves (1.04). Reduced age and Risser stage, thoracic curves, increased pre-brace Cobb angle, and reduced correction and flexibility rates predicted increased likelihood of curve progression. Flexibility rate of more than 28% has likelihood of preventing curve progression with bracing. Conclusion. Supine radiographs provide satisfactory prediction for in-brace correction and post-bracing curve magnitude. The flexibility of the curve is a guide to determine the likelihood for brace success. Cite this article: Bone Joint J 2020;102-B(2):254–260

Aims. A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement. Patients and Methods. The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of ‘borderline dysplastic hips’ with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of ‘borderline dysplastic hips’ with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index. Results. The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (. sd. 9.1°)) compared with the unstable borderline group (mean 7.9° (. sd. 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI. Conclusion. The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578–1584

Aims. Porous metaphyseal cones can be used for fixation in revision total knee arthroplasty (rTKA) and complex TKAs. This metaphyseal fixation has led to some surgeons using shorter cemented stems instead of diaphyseal engaging cementless stems with a potential benefit of ease of obtaining proper alignment without being beholden to the diaphysis. The purpose of this study was to evaluate short term clinical and radiographic outcomes of a series of TKA cases performed using 3D-printed metaphyseal cones. Methods. A retrospective review of 86 rTKAs and nine complex primary TKAs, with an average age of 63.2 years (SD 8.2) and BMI of 34.0 kg/m. 2. (SD 8.7), in which metaphyseal cones were used for both femoral and tibial fixation were compared for their knee alignment based on the type of stem used. Overall, 22 knees had cementless stems on both sides, 52 had cemented stems on both sides, and 15 had mixed stems. Postoperative long-standing radiographs were evaluated for coronal and sagittal plane alignment. Adjusted logistic regression models were run to assess malalignment hip-knee-ankle (HKA) alignment beyond ± 3° and sagittal alignment of the tibial and femoral components ± 3° by stem type. Results. No patients had a revision of a cone due to aseptic loosening; however, two had revision surgery due to infection. In all, 26 (27%) patients had HKA malalignment; nine (9.5%) patients had sagittal plane malalignment, five (5.6%) of the tibia, and four (10.8%) of the femur. After adjusting for age, sex, and BMI, there was a significantly increased risk for malalignment when a cone was used and both the femur and tibia had cementless compared to cemented stems (odds ratio 3.19, 95% confidence interval 1.01 to 10.05). Conclusion. Porous 3D-printed cones provide excellent metaphyseal fixation. However, these central cones make the use of offset couplers difficult and may generate malalignment with cementless stems. We found 3.19-times higher odds of malalignment in our TKAs performed with metaphyseal cones and both femoral and tibial cementless stems. Cite this article: Bone Joint J 2021;103-B(6 Supple A):150–157

Aims. The management of completely displaced fractures of the distal radius in children remains controversial. This study evaluates the outcomes of surgical and non-surgical management of ‘off-ended’ fractures in children with at least two years of potential growth remaining. Methods. A total of 34 boys and 22 girls aged 0 to ten years with a closed, completely displaced metaphyseal distal radial fracture presented between 1 November 2015 and 1 January 2020. After 2018, children aged ten or under were offered treatment in a straight plaster or manipulation under anaesthesia with Kirschner (K-)wire stabilization. Case notes and radiographs were reviewed to evaluate outcomes. In all, 16 underwent treatment in a straight cast and 40 had manipulation under anaesthesia, including 37 stabilized with K-wires. Results. Of the children treated in a straight cast, all were discharged with good range of mo (ROM). Five children were discharged at six to 12 weeks with no functional limitations at six-month follow-up. A total of 11 children were discharged between 12 and 50 weeks with a normal ROM and radiological evidence of remodelling. One child had a subsequent diaphyseal fracture proximal to the original injury four years after the initial fracture. Re-displacement with angulation greater than 10° occurred for 17 children who had manipulation under anaesthesia. Four had a visible cosmetic deformity at discharge and nine had restriction of movement, with four requiring physiotherapy. One child developed over- granulation at the pin site and one wire became buried, resulting in a difficult retrieval in clinic. No children had pin site infections. Conclusion. Nonoperative management of completely displaced distal radial fractures in appropriately selected cases results in excellent outcomes without exposing the child to the risks of surgery. This study suggests that nonoperative management of these injuries is a viable and potentially underused strategy. Cite this article: Bone Joint J 2021;103-B(5):902–907

Aims. To benchmark the radiation dose to patients during the course of treatment for a spinal deformity. Methods. Our radiation dose database identified 25,745 exposures of 6,017 children (under 18 years of age) and adults treated for a spinal deformity between 1 January 2008 and 31 December 2016. Patients were divided into surgical (974 patients) and non-surgical (5,043 patients) cohorts. We documented the number and doses of ionizing radiation imaging events (radiographs, CT scans, or intraoperative fluoroscopy) for each patient. All the doses for plain radiographs, CT scans, and intraoperative fluoroscopy were combined into a single effective dose by a medical physicist (milliSivert (mSv)). Results. There were more ionizing radiation-based imaging events and higher radiation dose exposures in the surgical group than in the non-surgical group (p < 0.001). The difference in effective dose for children between the surgical and non-surgical groups was statistically significant, the surgical group being significantly higher (p < 0.001). This led to a higher estimated risk of cancer induction for the surgical group (1:222 surgical vs 1:1,418 non-surgical). However, the dose difference for adults was not statistically different between the surgical and non-surgical groups. In all cases the effective dose received by all cohorts was significantly higher than that from exposure to natural background radiation. Conclusion. The treatment of spinal deformity is radiation-heavy. The dose exposure is several times higher when surgical treatment is undertaken. Clinicians should be aware of this and review their practices in order to reduce the radiation dose where possible. Cite this article: Bone Joint J 2021;103-B(4):1–7

Aims. Ideal component sizing may be difficult to achieve in unicompartmental knee arthroplasty (UKA). Anatomical variants, incremental implant size, and a reduced surgical exposure may lead to over- or under-sizing of the components. The purpose of this study was to compare the accuracy of UKA sizing with robotic-assisted techniques versus a conventional surgical technique. Methods. Three groups of 93 medial UKAs were assessed. The first group was performed by a conventional technique, the second group with an image-free robotic-assisted system (Image-Free group), and the last group with an image-based robotic arm-assisted system, using a preoperative CT scan (Image-Based group). There were no demographic differences between groups. We compared six parameters on postoperative radiographs to assess UKA sizing. Incorrect sizing was defined by an over- or under-sizing greater than 3 mm. Results. There was a higher rate of tibial under-sizing posteriorly in the conventional group compared to robotic-assisted groups (47.3% (n = 44) in conventional group, 29% (n = 27) in Image-Free group, 6.5% (n = 6) in Image-Based group; p < 0.001), as well as a higher rate of femoral under-sizing posteriorly (30.1% (n = 28) in conventional group, 7.5% (n = 7) in Image-Free group, 12.9% (n = 12) in Image-Based group; p < 0.001). The posterior femoral offset was more often increased in the conventional group, especially in comparison to the Image-Based group (43% (n = 40) in conventional group, 30.1% (n = 28) in Image-Free group, 8.6% (n = 8) in Image-Based group; p < 0.001). There was no significant overhang of the femoral or tibial implant in any groups. Conclusion. Robotic-assisted surgical techniques for medial UKA decrease the risk of tibial and femoral under-sizing, particularly with an image-based system using a preoperative CT scan. Cite this article: Bone Joint J 2021;103-B(4):610–618

Aims. This study evaluated variation in the surgical treatment of stable (A1) and unstable (A2) trochanteric hip fractures among an international group of orthopaedic surgeons, and determined the influence of patient, fracture, and surgeon characteristics on choice of implant (intramedullary nailing (IMN) versus sliding hip screw (SHS)). Methods. A total of 128 orthopaedic surgeons in the Science of Variation Group evaluated radiographs of 30 patients with Type A1 and A2 trochanteric hip fractures and indicated their preferred treatment: IMN or SHS. The management of Type A3 (reverse obliquity) trochanteric fractures was not evaluated. Agreement between surgeons was calculated using multirater kappa. Multivariate logistic regression models were used to assess whether patient, fracture, and surgeon characteristics were independently associated with choice of implant. Results. The overall agreement between surgeons on implant choice was fair (kappa = 0.27 (95% confidence interval (CI) 0.25 to 0.28)). Factors associated with preference for IMN included USA compared to Europe or the UK (Europe odds ratio (OR) 0.56 (95% CI 0.47 to 0.67); UK OR 0.16 (95% CI 0.12 to 0.22); p < 0.001); exposure to IMN only during training compared to surgeons that were exposed to both (only IMN during training OR 2.6 (95% CI 2.0 to 3.4); p < 0.001); and A2 compared to A1 fractures (Type A2 OR 10 (95% CI 8.4 to 12); p < 0.001). Conclusion. In an international cohort of orthopaedic surgeons, there was a large variation in implant preference for patients with A1 and A2 trochanteric fractures. This is due to surgeon bias (country of practice and aspects of training). The observation that surgeons favoured the more expensive implant (IMN) in the absence of convincing evidence of its superiority suggests that surgeon de-biasing strategies may be a useful focus for optimizing patient outcomes and promoting value-based healthcare. Cite this article: Bone Joint J 2021;103-B(4):775–781

Aims. To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component. Methods. Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed. Results. A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted. Conclusion. Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway. Cite this article: Bone Jt Open 2021;2(9):728–736