Aims. The aim of this study was to determine if uncemented acetabular polyethylene (PE) liner geometry, and lip size, influenced the risk of revision for instability or loosening. Methods. A total of 202,511 primary total hip arthroplasties (THAs) with uncemented acetabular components were identified from the National Joint Registry (NJR) dataset between 2003 and 2017. The effect of liner geometry on the risk of revision for instability or loosening was investigated using competing risk regression analyses adjusting for age, sex, American Society of Anesthesiologists grade, indication, side, institution type, surgeon grade, surgical approach, head size, and polyethylene crosslinking. Stratified analyses by surgical approach were performed, including pairwise comparisons of liner geometries. Results. The distribution of liner geometries were neutral (39.4%; 79,822), 10° (34.5%; 69,894), 15° (21.6%; 43,722), offset reorientating (2.8%; 5705), offset neutral (0.9%; 1,767), and 20° (0.8%; 1,601). There were 690 (0.34%) revisions for instability. Compared to neutral liners, the adjusted subhazard ratios of revision for instability were: 10°, 0.64 (p < 0.001); 15°, 0.48 (p < 0.001); and offset reorientating, 1.6 (p = 0.010). No association was found with other geometries. 10° and 15° liners had a time-dependent lower risk of revision for instability within the first 1.2 years. In posterior approaches, 10° and 15° liners had a lower risk of revision for instability, with no significant difference between them. The protective effect of lipped over neutral liners was not observed in laterally approached THAs. There were 604 (0.3%) revisions for loosening, but no association between liner geometry and revision for loosening was found. Conclusion. This registry-based study confirms a lower risk of revision for instability in posterior approach THAs with 10° or 15° lipped liners compared to neutral liners, but no significant difference between these lip sizes. A higher revision risk is seen with offset reorientating liners. The benefit of lipped geometries against revision for instability was not seen in laterally approached THAs. Liner geometry does not seem to influence the risk of revision for loosening. Cite this article: Bone Joint J 2021;103-B(12):1774–1782

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The aim of this study was to report the pooled prevalence of post-traumatic osteoarthritis (PTOA) and examine whether the risk of developing PTOA after anterior cruciate ligament (ACL) injury has decreased in recent decades.

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This study aimed to compare mortality in trochanteric AO/OTA A1 and A2 fractures treated with an intramedullary nail (IMN) or sliding hip screw (SHS). The primary endpoint was 30-day mortality, with secondary endpoints at 0 to 1, 2 to 7, 8 to 30, 90, and 365 days.

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For the increasing number of working-age patients undergoing total hip or total knee arthroplasty (THA/TKA), return to work (RTW) after surgery is crucial. We investigated the association between occupational class and time to RTW after THA or TKA.

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This study aimed to compare the performance of survival prediction models for bone metastases of the extremities (BM-E) with pathological fractures in an Asian cohort, and investigate patient characteristics associated with survival.

Aims. With novel promising therapies potentially limiting progression of Dupuytren’s disease (DD), better patient stratification is needed. We aimed to quantify DD development and progression after seven years in a population-based cohort, and to identify factors predictive of disease development or progression. Methods. All surviving participants from our previous prevalence study were invited to participate in the current prospective cohort study. Participants were examined for presence of DD and Iselin’s classification was applied. They were asked to complete comprehensive questionnaires. Disease progression was defined as advancement to a further Iselin stage or surgery. Potential predictive factors were assessed using multivariable regression analyses. Of 763 participants in our original study, 398 were available for further investigation seven years later. Results. We identified 143/398 (35.9%) participants with DD, of whom 56 (39.2%) were newly diagnosed. Overall, 20/93 (21.5%) previously affected participants had disease progression, while 6/93 (6.5%) patients showed disease regression. Disease progression occurred more often in patients who initially had advanced disease. Multivariable regression analyses revealed that both ectopic lesions and a positive family history of DD are independent predictors of disease progression. Previous hand injury predicts development of DD. Conclusion. Disease progression occurred in 21.5% of DD patients in our study. The higher the initial disease stage, the greater the proportion of participants who had disease progression at follow-up. Both ectopic lesions and a positive family history of DD predict disease progression. These patient-specific factors may be used to identify patients who might benefit from treatment that prevents progression. Cite this article: Bone Joint J 2021;103-B(4):704–710

Aims. Rotating-hinge knee prostheses are commonly used to reconstruct the distal femur after resection of a tumour, despite the projected long-term burden of reoperation due to complications. Few studies have examined the factors that influence their failure and none, to our knowledge, have used competing risk models to do so. The purpose of this study was to determine the risk factors for failure of a rotating-hinge knee distal femoral arthroplasty using the Fine-Gray competing risk model. Methods. We retrospectively reviewed 209 consecutive patients who, between 1991 and 2016, had undergone resection of the distal femur for tumour and reconstruction using a rotating-hinge knee prosthesis. The study endpoint was failure of the prosthesis, defined as removal of the femoral component, the tibial component, or the bone-implant fixation; major revision (exchange of the femoral component, tibial component, or the bone-implant fixation); or amputation. Results. Multivariate Fine-Gray regression analyses revealed different hazards for each Henderson failure mode: percentage of femoral resection (p = 0.001) and extent of quadriceps muscle resection (p = 0.005) for overall prosthetic failure; extent of quadriceps muscle resection (p = 0.002) and fixation of femoral component (p = 0.011) for type 2 failure (aseptic loosening); age (p = 0.009) and percentage of femoral resection (p = 0.019) for type 3 failure (mechanical failure); and type of joint resection (p = 0.037) for type 4 (infection) were independent predictors. A bone stem ratio of > 2.5 reliably predicted aseptic loosening. Conclusion. We identified independent risk factors for overall and cause-specific prosthetic failure after rotating-hinge knee distal femoral arthroplasty using a competing risk Fine-Gray model. A bone stem ratio > 2.5 reliably predicts aseptic loosening. An accurate knowledge of the risks of distal femoral arthroplasty after resection for tumour assists surgical planning and managing patient expectations. Cite this article: Bone Joint J 2021;103-B(8):1405–1413

Aims. Although there is increasing legalization of the use of cannabis in the USA, few well-powered studies have evaluated the association between cannabis use disorder and outcomes following primary total hip arthroplasty (THA). Thus, the aim of this study was to determine whether patients who use cannabis and undergo primary THA have higher rates of in-hospital length of stay (LOS), medical complications, implant-related complications, and costs. Methods. Using an administrative database, patients with cannabis use disorder undergoing primary THA were matched to a control group in a 1:5 ratio by age, sex, and various medical comorbidities. This yielded 23,030 patients (3,842 in the study group matched with 19,188 in the control group). The variables which were studied included LOS, 90-day medical complications, two-year implant-related complications, and 90-day costs of care. Mann-Whitney U tests were used to compare LOS and costs. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of developing complications. Results. We found that patients in the study group had a significantly longer mean LOS compared with the controls (four days vs three days; p < 0.0001).The study group also had a significantly higher incidence and odds of developing medical (23.0 vs 9.8%, OR 1.6; p < 0.0001) and implant-related complications (16 vs 7.4%, OR 1.6; p < 0.0001) and incurred significantly higher mean 90-day costs ($16,938.00 vs $16,023.00; p < 0.0001). Conclusion. With the increasing rates of cannabis use, these findings allow orthopaedic surgeons and other healthcare professionals to counsel patients with cannabis use disorder about the possible outcomes following their THA, with increased hospital stays, complications, and costs. Cite this article: Bone Joint J 2021;103-B(7 Supple B):111–115

Aims. This study aimed to evaluate the association between the sagittal alignment of the femoral component in total knee arthroplasty (TKA) and new Knee Society Score (2011KSS), under the hypothesis that outliers such as the excessive extended or flexed femoral component were related to worse clinical outcomes. Methods. A group of 156 knees (134 F:22 M) in 133 patients with a mean age 75.8 years (SD 6.4) who underwent TKA with the cruciate-substituting Bi-Surface Knee prosthesis were retrospectively enrolled. On lateral radiographs, γ angle (the angle between the distal femoral axis and the line perpendicular to the distal rear surface of the femoral component) was measured, and the patients were divided into four groups according to the γ angle. The 2011KSSs among groups were compared using the Kruskal-Wallis test. A secondary regression analysis was used to investigate the association between the 2011KSS and γ angle. Results. According to the mean and SD of γ angle (γ, 4.0 SD 3.0°), four groups (Extended or minor flexed group, −0.5° ≤ γ < 2.5° (n = 54)), Mild flexed group (2.5° ≤ γ < 5.5° (n = 63)), Moderate flexed group (5.5° ≤ γ < 8.5° (n = 26)), and Excessive flexed group (8.5° ≤ γ (n = 13)) were defined. The Excessive flexed group showed worse 2011KSSs in all subdomains (Symptoms, Satisfaction, Expectations, and Functional activities) than the Mild flexed group. Secondary regression showed a convex upward function, and the scores were highest at γ = 3.0°, 4.0°, and 3.0° in Satisfaction, Expectations, and Functional activities, respectively. Conclusion. The groups with a sagittal alignment of the femoral component > 8.5° showed inferior clinical outcomes in 2011KSSs. Secondary regression analyses showed that mild flexion of the femoral component was associated with the highest score. When implanting the Bi-Surface Knee prosthesis surgeons should pay careful attention to avoiding flexing the femoral component extensively during TKA. Our findings may be applicable to other implant designs. Cite this article: Bone Joint J 2020;102-B(6 Supple A):36–42

Aims. The primary aim of this study was to assess if traumatic triangular fibrocartilage complex (TFCC) tears can be treated successfully with immobilization alone. Our secondary aims were to identify clinical factors that may predict a poor prognosis. Methods. This was a retrospective analysis of 89 wrists in 88 patients between January 2015 and January 2019. All patients were managed conservatively initially with either a short-arm or above-elbow custom-moulded thermoplastic splint for six weeks. Outcome measures recorded included a visual analogue scale for pain, Patient-Rated Wrist Evaluation, Disabilities of the Arm, Shoulder and Hand score, and the modified Mayo Wrist Score (MMWS). Patients were considered to have had a poor outcome if their final MMWS was less than 80 points, or if they required eventual surgical intervention. Univariate and logistic regression analyses were used to identify independent predictors for a poor outcome. Results. In total, 76% of wrists (42/55) treated with an above-elbow splint had a good outcome, compared to only 29% (10/34) with a short-arm splint (p < 0.001). The presence of a complete foveal TFCC tear (p = 0.009) and a dorsally subluxated distal radioulnar joint (DRUJ) (p = 0.032) were significantly associated with a poor outcome on univariate analysis. Sex, age, energy of injury, hand dominance, manual occupation, ulnar variance, and a delay in initial treatment demonstrated no significant association. Multiple logistic regression revealed that short-arm immobilization (p < 0.001) and DRUJ subluxation (p = 0.020) were significant independent predictive factors of an eventual poor outcome. Conclusion. Nonoperative management of traumatic TFCC injuries with above-elbow immobilization is a viable treatment method, particularly in patients without DRUJ subluxation. Early surgery should be considered for patients with dorsal ulnar subluxation treated with short-arm splints to prevent prolonged morbidity. Cite this article: Bone Joint J 2021;103-B(8):1386–1391

Aims. Acetabular fractures in older adults lead to a high risk of mortality and morbidity. However, only limited data have been published documenting functional outcomes in such patients. The aims of this study were to describe outcomes in patients aged 60 years and older with operatively managed acetabular fractures, and to establish predictors of conversion to total hip arthroplasty (THA). Methods. We conducted a retrospective, registry-based study of 80 patients aged 60 years and older with acetabular fractures treated surgically at The Alfred and Royal Melbourne Hospital. We reviewed charts and radiological investigations and performed patient interviews/examinations and functional outcome scoring. Data were provided by the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). Survival analysis was used to describe conversion to THA in the group of patients who initially underwent open reduction and internal fixation (ORIF). Multivariate regression analyses were performed to identify factors associated with conversion to THA. Results. Seven patients (8.8%) had died at a median follow-up of 18 months (interquartile range (IQR) 12 to 25), of whom four were in the acute THA group. Eight patients (10%) underwent acute THA. Of the patients who underwent ORIF, 17/72 (23.6%) required conversion to THA at a median of 10.5 months (IQR 4.0 to 32.0) . After controlling for other factors, transport-related cases had an 88% lower rate of conversion to THA (hazard ratio (HR) 0.12, 95% confidence interval (CI) 0.02 to 0.91). Mean standardized Physical Component Summary Score (PCS-12) of the 12-Item Short Form Health Survey (SF-12) was comparable with the general population (age-/sex-matched) by 12 to 24 months. Over half of patients working prior to injury (14/26) returned to work by six months and two-thirds of patients (19/27) by 12 months. Conclusion. Patients over 60 years of age managed operatively for displaced acetabular fractures had a relatively high mortality rate and a high conversion rate to THA in the ORIF group but, overall, patients who survived had mean PCS-12 scores that improved over two years and were comparable with controls. Cite this article: Bone Joint J 2020;102-B(12):1735–1742

Aims. Although internal hemipelvectomy is associated with a high incidence of morbidity, especially wound complications, few studies have examined rates of wound complications in these patients or have identified factors associated with the consequences. The present study aimed to: 1) determine the rate of wound and other complications requiring surgery after internal hemipelvectomy; and 2) identify factors that affect the rate of wound complications and can be used to stratify patients by risk of wound complications. Methods. The medical records of 123 patients undergoing internal hemipelvectomy were retrospectively reviewed, with a focus on both overall complications and wound complications. Logistic regression analyses were performed to examine the association between host, tumour, and surgical factors and rates of postoperative wound complications. Results. The overall rate of postoperative complications requiring surgery was 49.6%. Wound complications were observed in 34.1% of patients, hardware-related complications in 13.2%, graft-related complications in 9.1%, and local recurrence in 5.7%. On multivariate analysis, extrapelvic tumour extension (odds ratio (OR) 23.28; 95% confidence interval (CI), 1.97 to 274.67; p = 0.012), both intra- and extrapelvic tumour extension (OR 46.48; 95% CI, 3.50 to 617.77; p = 0.004), blood transfusion ≥ 20 units (OR 50.28; 95% CI, 1.63 to 1550.32; p = 0.025), vascular sacrifice of the internal iliac artery (OR 64.56; 95% CI, 6.33 to 658.43; p < 0.001), and use of a structural allograft (OR, 6.57; 95% CI, 1.70 to 25.34; p = 0.001) were significantly associated with postoperative wound complications. Conclusion. Internal hemipelvectomy is associated with high rates of morbidity, especially wound complications. Several host, tumour, and surgical variables are associated with wound complications. The ability to stratify patients by risk of wound complications can help refine surgical and wound-healing planning and may lead to better outcomes in patients undergoing internal hemipelvectomy. Cite this article: Bone Joint J 2020;102-B(3):280–284

Aims. Social determinants of health (SDOHs) may contribute to the total cost of care (TCOC) for patients undergoing total knee arthroplasty (TKA). The aim of this study was to investigate the association between demographic data, health status, and SDOHs on 30-day length of stay (LOS) and TCOC after this procedure. Methods. Patients who underwent TKA between 1 January 2018 and 31 December 2019 were identified. A total of 234 patients with complete SDOH data were included. Data were drawn from the Chesapeake Regional Information System, the Centers for Disease Control social vulnerability index (SVI), the US Department of Agriculture, and institutional electronic medical records. The SVI identifies areas vulnerable to catastrophic events with four themed scores: socioeconomic status; household composition and disability; minority status and language; and housing and transportation. Food deserts were defined as neighbourhoods located one or ten miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine associations with LOS and costs after controlling for various demographic parameters. Results. Divorced status was significantly associated with an increased LOS (p = 0.043). Comorbidities significantly associated with an increased LOS included chronic obstructive pulmonary disease/asthma and congestive heart failure (p = 0.043 and p = 0.001, respectively). Communities with a higher density of tobacco stores were significantly associated with an increased LOS (p = 0.017). Comorbidities significantly associated with an increased TCOC included chronic obstructive pulmonary disease (p = 0.004), dementia (p = 0.048), and heart failure (p = 0.007). Increased TCOCs were significantly associated with patients who lived in food deserts (p = 0.001) and in areas with an increased density of tobacco stores (p = 0.023). Conclusion. Divorced marital status was significantly associated with an increased LOS following TKA. Living in food deserts and in communities with more tobacco stores were significant risk factors for increased LOS and TCOC. Food access and ease of acquiring tobacco may both prove to be prognostic of outcome after TKA and an opportunity for intervention. Cite this article: Bone Joint J 2021;103-B(6 Supple A):113–118

Aims. Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome. Patients and Methods. This prospective study included 42 patients (42 knees) with varus-type osteoarthritis who underwent a bi-cruciate stabilized total knee arthroplasty and in whom the planned alignment was confirmed on 3D CT. Of the 42 patients, 36 were women and six were men. Their mean age was 72.3 years (61 to 87) and their mean body mass index (BMI) was 24.4 kg/m2 (18.2 to 34.3). After implantation of the femoral and tibial components, the compressive force across the patellofemoral joint was measured at 10°, 30°, 60°, 90°, 120°, and 140° of flexion using a load cell (Kyowa Electronic Instruments Co., Ltd., Tokyo, Japan) manufactured in the same shape as the patellar implant. Multiple regression analyses were conducted to investigate the relationship between intraoperative patellofemoral compressive force and patient-reported outcome two years after implantation. Results. No patient had anterior knee pain after total knee arthroplasty. The compressive force across the patellofemoral joint at 140°of flexion was negatively correlated with patient satisfaction (R2 = 0.458; β = –0.706; p = 0. 041) and Forgotten Joint Score-12 (FJS-12; R2= .378; β = –0.636; p = 0. 036). The compressive force across the patellofemoral joint at 60° of flexion was negatively correlated with the patella score (R2 = 0.417; β = –0.688; p = 0. 046). Conclusion. Patient satisfaction, FJS-12, and patella score were affected by the patellofemoral compressive force at 60° and 140° of flexion. Reduction of the patellofemoral compressive forces at 60° and 140° of flexion angle during total knee arthroplasty may improve patient-reported outcome, but has no effect on anterior knee pain

Aims. The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse. Patients and Methods. We identified 121 patients with bilateral non-traumatic osteonecrosis who underwent THA between 2003 and 2011 to treat a symptomatic hip, and who also exhibited medium-to-large lesions (necrotic area ≥ 30%) in an otherwise asymptomatic non-operated hip. Of the 121 patients, 71 were male (59%) and 50 were female (41%), with a mean age of 51 years (19 to 71) at the time of initial THA. All patients were followed for at least five years and were assessed according to the presence of a LLD (non-LLD vs LLD group), as well as the LLD type (longer non-operated side vs shorter non-operated side group). Results. Overall, 68 hips (56%) became painful and progressed to collapse at a mean of 2.6 years (0.2 to 13.8), resulting in 59 THAs (49%). The five-year collapse-free survival rate for the non-LLD group was 59% (95% confidence interval (CI) 46.8 to 71.8) compared with 45% (95% CI 32.9 to 57.5) for the LLD group (p = 0.036), and 66% (95% CI 55.2 to 77.2) for the longer non-operated side group compared with 32% (95% CI 19.1 to 44.9) for the shorter non-operated side group (p < 0.001). Multivariate regression analyses found that large lesions had a higher risk of collapse than medium-size lesions (odds ratio (OR) 4.19, 95% confidence interval (CI) 1.69 to 10.38; p = 0.002). Meanwhile, patients with a LLD < 3 mm (OR 0.20, 95% CI 0.08 to 0.52; p = 0.001) or a longer non-operated leg (OR 0.11, 95% CI 0.04 to 0.28; p < 0.001) after THA were less likely to experience a subsequent collapse. Conclusion. We found that LLD may be a modifiable risk factor for femoral head collapse. Minimizing LLD and particularly avoiding a shorter non-operated limb after THA may lead to a lower risk of collapse of the asymptomatic hip in patients with bilateral non-traumatic osteonecrosis. Cite this article: Bone Joint J 2019;101-B:303–310

Aims. The aim of this study was to identify modifiable risk factors associated with mortality in patients requiring revision total hip arthroplasty (THA) for periprosthetic hip fracture. Methods. The electronic records of consecutive patients undergoing revision THA for periprosthetic hip fracture between December 2011 and October 2018 were reviewed. The data which were collected included age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, the preoperative serum level of haemoglobin, time to surgery, operating time, blood transfusion, length of hospital stay, and postoperative surgical and medical complications. Univariate and multivariate logistic regression analyses were used to determine independent modifiable factors associated with mortality at 90 days and one year postoperatively. Results. A total of 203 patients were identified. Their mean age was 78 years (44 to 100), and 108 (53%) were female. The median time to surgery was three days (interquartile range (IQR) 2 to 5). The mortality rate at one year was 13.8% (n = 28). The commonest surgical complication was dislocation (n = 22, 10.8%) and the commonest medical complication within 90 days of surgery was hospital-acquired pneumonia (n = 25, 12%). Multivariate analysis showed that the rate of mortality one year postoperatively was five-fold higher in patients who sustained a dislocation (odds ratio (OR) 5.03 (95% confidence interval (CI) 1.60 to 15.83); p = 0.006). The rate of mortality was also four-fold higher in patients who developed hospital-acquired pneumonia within 90 days postoperatively (OR 4.43 (95% CI 1.55 to 12.67); p = 0.005). There was no evidence that the time to surgery was a risk factor for death at one year. Conclusion. Dislocation and hospital-acquired pneumonia following revision THA for a periprosthetic fracture are potentially modifiable risk factors for mortality. This study suggests that surgeons should consider increasing constraint to reduce the risk of dislocation, and the early involvement of a multidisciplinary team to reduce the risk of hospital-acquired pneumonia. We found no evidence that the time to surgery affected mortality, which may allow time for medical optimization, surgical planning, and resource allocation. Cite this article: Bone Joint J 2020;102-B(5):580–585

Aims. The aim of this study was to explore risk factors for complications associated with dural tear (DT), including the types of DT, and the intra- and postoperative management of DT. Patients and Methods. Between 2012 and 2017, 12 171 patients with degenerative lumbar diseases underwent primary lumbar spine surgery. We investigated five categories of potential predictors: patient factors (sex, age, body mass index, and primary disease), surgical factors (surgical procedures, operative time, and estimated blood loss), types of DT (inaccessible for suturing/clipping and the presence of cauda equina/nerve root herniation), repair techniques (suturing, clipping, fibrin glue, polyethylene glycol (PEG) hydrogel, and polyglycolic acid sheet), and postoperative management (drainage duration). Postoperative complications were evaluated in terms of dural leak, prolonged bed rest, headache, nausea/vomiting, delayed wound healing, postoperative neurological deficit, surgical site infection (SSI), and reoperation for DT. We performed multivariable regression analyses to evaluate the predictors of postoperative complications associated with DT. Results. In total, 429/12 171 patients (3.5%) had a DT. Multivariable analysis revealed that PEG hydrogel significantly reduced the incidence of dural leak and prolonged bed rest, and that patients treated with sealants (fibrin glue and PEG hydrogel) significantly less frequently suffered from headache. A longer drainage duration significantly increased the incidence of headache, nausea/vomiting, and delayed wound healing. Headache and nausea/vomiting were significantly more prevalent in younger female patients. Postoperative neurological deficit and reoperation for DT significantly depended on the presence of cauda equina/nerve root herniation. A longer operative time was the sole independent risk factor for SSI and was also a risk factor for dural leak, prolonged bed rest, and nausea/vomiting. Conclusion. Sealants, particularly PEG hydrogel, may be useful in reducing symptoms related to cerebrospinal fluid leakage, whereas prolonged drainage may be unnecessary. Younger female patients should be carefully treated when DT occurs. Cite this article: Bone Joint J 2019;101-B:1115–1121

A prospective cohort of 222 patients who underwent revision hip replacement between April 2001 and March 2004 was evaluated to determine predictors of function, pain and activity level between one and two years post-operatively, and to define quality of life outcomes using validated patient reported outcome tools. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at one and two years post-operatively. The dependent outcome variables were the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function and pain scores, and University of California Los Angeles activity scores. The independent variables included patient demographics, operative factors, and objective quality of life parameters, including pre-operative WOMAC, and the Short Form-12 mental component score. There was a significant improvement (t-test, p < 0.001) in all patient quality of life scores. In the predictive model, factors predictive of improved function (original regression analyses, p < 0.05) included a higher pre-operative WOMAC function score (p < 0.001), age between 60 and 70 years (p < 0.037), male gender (p = 0.017), lower Charnley class (p < 0.001) and aseptic loosening being the indication for revision (p < 0.003). Using the WOMAC pain score as an outcome variable, factors predictive of improvement included the pre-operative WOMAC function score (p = 0.001), age between 60 and 70 years (p = 0.004), male gender (p = 0.005), lower Charnley class (p = 0.001) and no previous revision procedure (p = 0.023). The pre-operative WOMAC function score (p = 0.001), the indication for the operation (p = 0.007), and the operating surgeon (p = 0.008) were significant predictors of the activity assessment at follow-up. Predictors of quality of life outcomes after revision hip replacement were established. Although some patient-specific and surgery-specific variables were important, age, gender, Charnley class and pre-operative WOMAC function score had the most robust associations with outcome

Aims. Total hip arthroplasty (THA) is gaining popularity as a treatment for displaced femoral neck fractures (FNFs), especially in physiologically younger patients. While THA for osteoarthritis (OA) has demonstrated low complication rates and increased quality of life, results of THA for acute FNF are not as clear. Currently, a THA performed for FNF is included in an institutional arthroplasty bundle without adequate risk adjustment, potentially placing centres participating in fracture care at financial disadvantage. The purpose of this study is to report on perioperative complication rates after THA for FNF compared with elective THA performed for OA of the hip. Patients and Methods. The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database between 2008 and 2016 was queried. Patients were identified using the THA Current Procedural Terminology (CPT) code and divided into groups by diagnosis: OA in one and FNF in another. Univariate statistics were performed. Continuous variables were compared between groups using Student’s t-test, and the chi-squared test was used to compare categorical variables. Multivariate and propensity-matched logistic regression analyses were performed to control for risk factors of interest. Results. Analyses included 139 635 patients undergoing THA. OA was the indication in 135 013 cases and FNF in 4622 cases. After propensity matching, mortality within 30 days (1.8% vs 0.3%; p < 0.001) and major morbidity (24.2% vs 19%; p < 0.001) were significantly higher among FNF patients. Re-operation (3.7% vs 2.7%; p = 0.014) and re-admission (7.3% vs 5.5%; p = 0.002) were significantly higher among FNF patients. Hip fracture patients had significantly longer operative time and length of stay (LOS), and were significantly less likely to be discharged to their home. Multivariate analyses gave similar results. Conclusion. This large database study showed a higher risk of postoperative complications including mortality, major morbidity, re-operation, re-admission, prolonged operative time, increased LOS, and decreased likelihood of discharge home in patients undergoing THA for FNF compared with OA. While THA is a good option for FNF patients, there are increased costs and financial risks to centres with a joint arthroplasty bundle programme participating in fracture care. Cite this article: Bone Joint J 2019;101-B(6 Supple B):84–90

After implementation of a ‘fast-track’ rehabilitation protocol in our hospital, mean length of hospital stay for primary total hip arthroplasty decreased from 4.6 to 2.9 nights for unselected patients. However, despite this reduction there was still a wide range across the patients’ hospital duration. The purpose of this study was to identify which specific patient characteristics influence length of stay after successful implementation of a ‘fast-track’ rehabilitation protocol. A total of 477 patients (317 female and 160 male, mean age 71.0 years; 39.3 to 92.6, mean BMI 27.0 kg/m. 2. ;18.8 to 45.2) who underwent primary total hip arthroplasty between 1 February 2011 and 31 January 2013, were included in this retrospective cohort study. A length of stay greater than the median was considered as an increased duration. Logistic regression analyses were performed to identify potential factors associated with increased durations. Median length of stay was two nights (interquartile range 1), and the mean length of stay 2.9 nights (1 to 75). In all, 266 patients had a length of stay ≤ two nights. Age (odds ratio (OR) 2.46; 95% confidence intervals (CI) 1.72 to 3.51; p <  0.001), living situation (alone vs living together with cohabitants, OR 2.09; 95% CI 1.33 to 3.30; p = 0.002) and approach (anterior approach vs lateral, OR 0.29; 95% CI 0.19 to 0.46; p <  0.001) (posterolateral approach vs lateral, OR 0.24; 95% CI 0.10 to 0.55; p < 0.001) were factors that were significantly associated with increased length of stay in the multivariable logistic regression model. Cite this article: Bone Joint J 2015;97-B:19–23

Aims. The aims of this study were to describe the prevalence of previous lumbar surgery in patients who undergo total hip arthroplasty (THA) and to investigate their patient-reported outcomes (PROMs) one year post-operatively. Patients and Methods. Data from the Swedish Hip Arthroplasty Register and the Swedish Spine Register gathered from 2002 to 2013 were merged to identify a group of patients who had undergone lumbar surgery before THA (n = 997) and a carefully matched one-to-one control group. We investigated differences in the one-year post-operative PROMs between the groups. Linear regression analyses were used to explore the associations between previous lumbar surgery and these PROMs following THA. The prevalence of prior lumbar surgery was calculated as the ratio of patients identified with previous lumbar surgery between 2002 and 2012, and divided by the total number of patients who underwent a THA in 2012. Results. The prevalence of lumbar surgery prior to THA in 2012 was 3.5% (351 of 10 082). Linear regression analyses showed an association with more pain (B = 4.35, 95% confidence interval (CI) 2.57 to 6.12), worse EuroQol (EQ)-5D index, (B = -0.089, 95% CI -0.112 to -0.066), worse EQ VAS (B = -6.75, 95% CI -8.58 to -4.92), and less satisfaction (B = 6.04, 95% CI 4.05 to 8.02). Conclusion. Lumbar spinal surgery prior to THA is associated with less reduction of pain, worse health-related quality of life, and less satisfaction one year after THA. This is useful information to share in the decision-making process and may help establish realistic expectations of the outcomes of THA in patients who also have previously undergone lumbar spinal surgery. Cite this article: Bone Joint J 2017;99-B:759–65

Forearm fractures in children have a tendency to displace in a cast leading to malunion with reduced functional and cosmetic results. In order to identify risk factors for displacement, a total of 247 conservatively treated fractures of the forearm in 246 children with a mean age of 7.3 years (. sd. 3.2; 0.9 to 14.9) were included in a prospective multicentre study. Multivariate logistic regression analyses were performed to assess risk factors for displacement of reduced or non-reduced fractures in the cast. Displacement occurred in 73 patients (29.6%), of which 65 (89.0%) were in above-elbow casts. The mean time between the injury and displacement was 22.7 days (0 to 59). The independent factors found to significantly increase the risk of displacement were a fracture of the non-dominant arm (p = 0.024), a complete fracture (p = 0.040), a fracture with translation of the ulna on lateral radiographs (p = 0.014) and shortening of the fracture (p = 0.019). Fractures of both forearm bones in children have a strong tendency to displace even in an above-elbow cast. Severe fractures of the non-dominant arm are at highest risk for displacement. Radiographs at set times during treatment might identify early displacement, which should be treated before malunion occurs, especially in older children with less potential for remodelling. Cite this article: Bone Joint J 2013;95-B:689–93

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The current evidence comparing the two most common approaches for reverse total shoulder arthroplasty (rTSA), the deltopectoral and anterosuperior approach, is limited. This study aims to compare the rate of loosening, instability, and implant survival between the two approaches for rTSA using data from the Dutch National Arthroplasty Registry with a minimum follow-up of five years.

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The aim of this study was to compare a bicruciate-retaining (BCR) total knee arthroplasty (TKA) with a posterior cruciate-retaining (CR) TKA design in terms of kinematics, measured using fluoroscopy and stability as micromotion using radiostereometric analysis (RSA).

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Postoperative length of stay (LOS) and discharge dispositions following arthroplasty can be used as surrogate measurements for improvements in patients’ pathways and costs. With the increasing use of robotic technology in arthroplasty, it is important to assess its impact on LOS. The aim of this study was to identify factors associated with decreased LOS following robotic arm-assisted total hip arthroplasty (RO THA) compared with the conventional technique (CO THA).

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The aim of this study was to assess factors associated with the estimated lifetime risk of revision surgery after primary knee arthroplasty (KA).

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The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors?

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Frailty greatly increases the risk of adverse outcome of trauma in older people. Frailty detection tools appear to be unsuitable for use in traumatically injured older patients. We therefore aimed to develop a method for detecting frailty in older people sustaining trauma using routinely collected clinical data.

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The aim of this study was to evaluate whether achieving medial joint opening, as measured by the change in the joint line convergence angle (∆JLCA), is a better predictor of clinical outcomes after high tibial osteotomy (HTO) compared with the mechanical axis deviation, and to find individualized targets for the redistribution of load that reflect bony alignment, joint laxity, and surgical technique.

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Although periacetabular osteotomies are widely used for the treatment of symptomatic dysplastic hips, long-term surgical outcomes and patient-reported outcome measures (PROMs) are still unclear. Accordingly, we assessed hip survival and PROMs at 20 years after transpositional osteotomy of the acetabulum (TOA).

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The prevalence of scoliosis is not known in patients with idiopathic short stature, and the impact of treatment with recombinant human growth hormone on those with scoliosis remains controversial. We investigated the prevalence of scoliosis radiologically in children with idiopathic short stature, and the impact of treatment with growth hormone in a cross-sectional and retrospective cohort study.

Literature surrounding artificial intelligence (AI)-related applications for hip and knee arthroplasty has proliferated. However, meaningful advances that fundamentally transform the practice and delivery of joint arthroplasty are yet to be realized, despite the broad range of applications as we continue to search for meaningful and appropriate use of AI. AI literature in hip and knee arthroplasty between 2018 and 2021 regarding image-based analyses, value-based care, remote patient monitoring, and augmented reality was reviewed. Concerns surrounding meaningful use and appropriate methodological approaches of AI in joint arthroplasty research are summarized. Of the 233 AI-related orthopaedics articles published, 178 (76%) constituted original research, while the rest consisted of editorials or reviews. A total of 52% of original AI-related research concerns hip and knee arthroplasty (n = 92), and a narrative review is described. Three studies were externally validated. Pitfalls surrounding present-day research include conflating vernacular (“AI/machine learning”), repackaging limited registry data, prematurely releasing internally validated prediction models, appraising model architecture instead of inputted data, withholding code, and evaluating studies using antiquated regression-based guidelines. While AI has been applied to a variety of hip and knee arthroplasty applications with limited clinical impact, the future remains promising if the question is meaningful, the methodology is rigorous and transparent, the data are rich, and the model is externally validated. Simple checkpoints for meaningful AI adoption include ensuring applications focus on: administrative support over clinical evaluation and management; necessity of the advanced model; and the novelty of the question being answered.

Cite this article: Bone Joint J 2022;104-B(12):1292–1303.

We aimed to highlight the relationship between age and the architectural properties of trabecular bone, to outline the patterns in which the variations in these properties take place, and to investigate the influence of the architecture on the mechanical properties of trabecular bone in growing animals. We studied 30 lambs in three age groups and 20 sheep in two age groups. Cubes of subchondral bone were cut from the proximal tibia according to a standardised protocol. They were serially sectioned and their architectural properties were determined. Similar cubes were obtained from the identical anatomical position of the contralateral tibia and their compressive mechanical properties measured. The values obtained from the skeletally immature and mature individuals were compared. Multiple regression analyses were performed between the architectural and the mechanical properties. The bone volume fraction, the mean trabecular volume, the architectural and the mechanical anisotropy, the elastic modulus, the bone strength, the energy absorption to failure, and the elastic energy correlated positively with increasing age whereas the connectivity density, the bone surface density, the ultimate strain, the absorption of viscoelastic energy and the relative loss of energy correlated inversely. The values of all variables were significantly different in the skeletally mature and immature groups. We determined the patterns in which the variations took place. The bone volume fraction of the trabecular bone tissue was found to be the major predictor of its compressive mechanical properties. Together with the mean trabecular volume and the bone surface density, it explained 81% of the variations in the compressive elastic modulus of specimens obtained from the contralateral tibiae

Our aim was to determine the relationship between age and the mechanical and physical properties of trabecular bone, to describe the patterns in which the variations in these properties take place, and to investigate the influence of the physical properties on the mechanical characteristics of trabecular bone during growth. We used 30 lambs in three age groups and 20 sheep in two age groups. Cubes of subchondral bone were cut from the proximal tibia according to a standardised protocol. We performed non-destructive compression tests of the specimens in three orthogonal directions and compression tests to failure in the axial direction. The physical properties of the specimens were also determined. The data were correlated with age and compared in skeletally immature and mature animals. Multiple regression analyses were performed between the mechanical and the physical properties. Age correlated positively with elastic modulus, bone strength, energy absorption to failure, elastic energy, mechanical anisotropy ratio, tissue density, apparent density, apparent ash density, and bone mineral content, and inversely with ultimate strain, viscoelastic energy absorption, relative energy loss, the collagen content of bone and the percentage porosity. The values of all variables were significantly different in the skeletally mature and immature groups. The apparent density of trabecular bone tissue was found to be the major predictor of its compressive mechanical properties. Together with the content of bone muscle and bone collagen, the apparent density could explain 84% of the variation in the elastic modulus, whereas only a small portion of the variation in ultimate strain could be explained by the variation in apparent density

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Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury.

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It is not known whether preservation of the capsule of the hip positively affects patient-reported outcome measures (PROMs) in total hip arthroplasty using the direct anterior approach (DAA-THA). A recent randomized controlled trial found no clinically significant difference at one year postoperatively. This study aimed to determine whether preservation of the anterolateral capsule and anatomical closure improve the outcome and revision rate, when compared with resection of the anterolateral capsule, at two years postoperatively.

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

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Heterotopic ossification (HO) is a common complication after elbow trauma and can cause severe upper limb disability. Although multiple prognostic factors have been reported to be associated with the development of post-traumatic HO, no model has yet been able to combine these predictors more succinctly to convey prognostic information and medical measures to patients. Therefore, this study aimed to identify prognostic factors leading to the formation of HO after surgery for elbow trauma, and to establish and validate a nomogram to predict the probability of HO formation in such particular injuries.

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The aim of this study was to assess the association of mortality and reoperation when comparing cemented and uncemented hemiarthroplasty (HA) in hip fracture patients aged over 65 years.

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To find out if there is an inverse association between estimated glomerular filtration rate (eGFR) and whole blood cobalt (Co) and chromium (Cr) levels in patients with metal-on-metal (MoM) hip arthroplasties and renal insufficiency, suggesting that renal insufficiency could cause accumulation of Co and Cr in blood.

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To determine if primary cemented acetabular component geometry (long posterior wall (LPW), hooded, or offset reorientating) influences the risk of revision total hip arthroplasty (THA) for instability or loosening.

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The aim of this study was to determine the long-term mortality rate, and to identify factors associated with this, following primary and revision knee arthroplasty (KA).

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The aim of the Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT) was to determine the optimal treatment for adults with a bicortical undisplaced or minimally displaced fracture of the waist of the scaphoid, comparing early surgical fixation with initial cast immobilization, with immediate fixation being offered to patients with nonunion.

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The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

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Wear of the polyethylene (PE) tibial insert of total knee arthroplasty (TKA) increases the risk of revision surgery with a significant cost burden on the healthcare system. This study quantifies wear performance of tibial inserts in a large and diverse series of retrieved TKAs to evaluate the effect of factors related to the patient, knee design, and bearing material on tibial insert wear performance.

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This study used an artificial neural network (ANN) model to determine the most important pre- and perioperative variables to predict same-day discharge in patients undergoing total knee arthroplasty (TKA).

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Time to treatment initiation (TTI) is generally defined as the time from the histological diagnosis of malignancy to the initiation of first definitive treatment. There is no consensus on the impact of TTI on the overall survival in patients with a soft-tissue sarcoma. The purpose of this study was to determine if an increased TTI is associated with overall survival in patients with a soft-tissue sarcoma, and to identify the factors associated with a prolonged TTI.

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The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort.

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This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases.

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The primary aim of this study was to assess whether non-fatal postoperative venous thromboembolism (VTE) within six months of surgery influences the knee-specific functional outcome (Oxford Knee Score (OKS)) one year after total knee arthroplasty (TKA). Secondary aims were to assess whether non-fatal postoperative VTE influences generic health and patient satisfaction at this time.