Abstract. Introduction. Risk factors for osteoarthritis include raised BMI and female gender. Whether these two factors influenced synovial gene expression was investigated using a triangulation and modelling strategy which generated 12 datasets of gene expression in synovial tissue from three knee pathologies with matching BMI groups, obese and overweight, and gender distributions. Methodology. Intra-operative synovial biopsies were immersed in RNAlater at 4oC before storage at -80oC. Total RNA was extracted using RNAeasy with gDNA removal. Following RT- PCR and quality assessment, cDNA was applied to Affymetrix Clariom D microarray gene chips. Bioinformatics analyses were performed. Linear models were prepared in limma with gender and BMI factors incorporated sequentially for each pathology comparison, generating 12 models of probes differentially expressed at FDR p<0.05 and Bayes number, B>0. Data analysis of differently expressed genes utilized Ingenuity Pathway Analysis and Cytoscape with Cluego and Cytohubba plug-ins. Results. Expression of 453 synovial genes was influenced by BMI and gender, 360 encode proteins such as HIF-1a, HSF1, HSPA4, HSPA5. Top canonical pathways include Unfolded protein response, Protein Ubiquiitation and Clathrin mediated endocytosis signalling linked by modulation of heat shock proteins, comparable to pathology dependent regulation. In addition BMI and gender modulate gene expression in the NRF2-mediated oxidative stress response pathway with down regulation of Glutathione-S-transferases potentially down regulating antioxidant defences. Conclusion. The enhanced risk of osteoarthritis induced by an elevated BMI and female gender maybe include differential expression of heat shock proteins and genes in the NRF2 pathway

Introduction. Body mass index (BMI) is a topical area of interest in the field of lower limb arthroplasty. It has been well established that BMI can influence post-operative outcomes. This study compares post-operative outcomes, including satisfaction rates, length of stay (LOS) and radiographic findings in different BMI groups following total hip arthroplasty (THA). Methods. We retrospectively evaluated all non-navigated THAs performed at our institution from 2006–2016. Case-notes were reviewed for dichotomised satisfaction score, LOS and radiographic parameters including inclination, anteversion, limb length discrepancy (LLD) and offset discrepancy. Patients were classified into 4 groupings based on BMI (underweight (<24.5), healthy (24.5–30), obese (30–40), severely obese (>40)). Appropriate statistical analyses were performed to identify between group differences. Results. A total of 6874 patients were included for analysis, (Male=2807, Female=4067, Age = 68.1, BMI=29.60). Satisfaction rates at 3 months and 1 year and LOS according to BMI are displayed in Table 1. Radiographic findings grouped by BMI are displayed in Table 2. Discussion/Conclusion. Satisfaction rates for all categories of BMI were excellent at 3 months (96.90%-98.02%) and 12 months (95.94%-98.32%), with no clinically significant differences between groups. BMI was associated with a significantly longer LOS for the underweight and the severely obese compared to the healthy group. There was no clinically significant influence of BMI on any of the radiographic findings reported. The obese and severely obese groups were significantly younger than the underweight and healthy groups, indicating BMI does appear to have an effect on the age where THA is considered a suitable treatment option in this patient group. For any figures or tables, please contact the authors directly

Abstract. Background. There is a trend towards minimising length of stay (LOS) after total knee arthroplasty (TKA), as longer LOS is associated with poorer outcomes and higher costs. Patient factors known to influence LOS after TKA include age and ASA grade. Evidence regarding body mass index (BMI) in particular is conflicting. Some studies find that increased BMI predicts greater LOS, while others find no such relationship. Previous studies have generally not examined socioeconomic status, which may be a confounder. They have generally been conducted outside the UK, and prior to the Covid-19 pandemic. Methods. We conducted a retrospective cohort study of 1031 primary TKAs performed 01-04-2021 to 31-12-2021, after resumption of elective surgery in our centre. A multivariate regression analysis was performed using a Poisson model over pre-operative variables (BMI, age, gender, ASA grade, index of multiple deprivation, and living arrangement) and peri-operative variables (AM/PM operation, operation side, duration, and day of the week). Results. Mean LOS was 2.6 days. BMI had no effect on LOS (p > 0.05). Longer LOS was experienced by patients of greater age (p < 0.001), increased ASA grade (p < 0.001), living alone (p < 0.01), PM start time (p < 0.001), and longer operation duration (p < 0.01). Male patients had shorter LOS (p < 0.001). Index of multiple deprivation had no effect (p > 0.05). Conclusion. BMI had no effect on LOS after TKA. Being female and living alone are significant risk factors which should be taken in to account in pre-operative planning

Total knee replacement (TKA) is one of the most successful procedures in orthopaedic surgery. Although originally limited to more elderly and less active individuals, the inclusion criteria for TKA have changed, with ever younger, more active and heavier patients receiving TKA. This broadening of indications coincided with the widespread adoption of modular cemented and cementless TKA systems in the 1980's, and soon thereafter wear debris related osteolysis and associated prosthetic loosening became major modes of failure for TKA implants of all designs. Initially, tibial components were cemented all polyethylene monoblock constructs. Subsequent long-term follow-up studies of some of these implant designs have demonstrated excellent durability in survivorship studies out to twenty years. While aseptic loosening of these all polyethylene tibial components was a leading cause of failure in these implants, major polyethylene wear-related osteolysis around well-fixed implants was rarely (if ever) observed. Cemented metal-backed nonmodular tibial components were first introduced to allow for improved tibial load distribution and protection of the underlying (often osteoporotic) bone. Eventually, modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80s mainly to facilitate screw fixation for cementless implants. These designs also provided intraoperative versatility by allowing interchange of various polyethylene thicknesses, and also aided the addition of stems and wedges. Modular vs. All Polyethylene Tibial Components in Primary TKA: Kremers et al. reviewed 10,601 adult (>18 years) patients with 14,524 condylar type primary TKA procedures performed at our institution between 1/1/1988 and 12/31/2005 and examined factors effecting outcome. The mean age was 68.7 years and 55% were female. Over an average 9 years follow-up, a total of 865 revisions, including 252 tibia revisions were performed, corresponding to overall survival of 89% (Confidence intervals (CI): 88%, 90%) at 15 years. In comparison to metal modular designs, risk of tibial revision was significantly lower with all polyethylene tibias (HR 0.3, 95% CI: 0.2, 0.5). With any revision as the endpoint, there were no significant differences across the 18 designs examined. Similarly, there were no significant differences across the 18 designs when we considered revisions for aseptic loosening, wear, osteolysis. Among patient characteristics, male gender, younger age, higher BMI were all significantly associated with higher risk of revisions (p<0.008). In a more recent review from our institution of over 11, 600 primary TKA procedures, Houdek et al. again showed that all polyethylene tibial components had superior survivorship vs. metal backed designs, with a lower risk of revision for loosening, osteolysis or component fracture. Furthermore, results for all polyethylene designs were better for all BMI subgroups except for those <25 BMI where there was no difference. All polyethylene results were also better for all age groups except for those under age <55 where there again was no difference. Finally, in a recently published meta-analysis of 28 articles containing data on 95,847 primary TKA procedures, all polyethylene tibial components were associated with a lower risk of revision and adverse outcomes. The available current data support the use of all polyethylene tibial designs in TKA in all patients regardless of age and BMI. In all patients, (not just older individuals) use of an all polyethylene tibial component is an attractive and more cost effective alternative, and is associated with the better survivorship and lower risk of revision than seen with modular metal backed tibial components

The effect of BMI on patient-reported outcomes following total ankle replacement (TAR) is uncertain and the change in BMI experienced by these patients in the 5 years following surgery has not been studied. We report a series of 106 patients with complete 5-year data on BMI and patient-reported outcome scores. Patients undergoing TAR between 2006 and 2009, took part in the hospital joint registry, which provides routine clinical audit of patient progress following total joint arthroplasty; therefore, ethics committee approval was not required for this study. Data on BMI, Foot and Ankle Score (FAOS) and SF-36 score were collected preoperatively and annually postoperatively. Patients who were obese (BMI >30) had lower FAOS scores pre-operatively and at 5 years, however this did not reach significance. Both obese (p = 0.0004) and non-obese (p < 0.0001) patients demonstrated a significant improvement in FAOS score from baseline to 5 years. This improvement was more marked for the non-obese patients. No significant differences were seen for SF36 scores between obese and non-obese patients either at baseline or 5 years. There was a trend for improved score in both groups. Mean pre-operative BMI was 28.49. Mean post-operative BMI was 28.33. The mean difference between pre- and post-operative BMI was −0.15, which was not statistically significant (p=0.55). There were no significant differences in revisions in the obese (2) and non-obese (1 and one awaited) groups at 5 years. This data supports use of TAR in the obese population, as significant increases in mean FAOS score were seen in this group at 5 years. Obesity did not have a significant influence on patients' overall health perceptions, measured by the SF36 and a trend for improvement was seen in both obese and non-obese patients. TAR cannot be relied upon to result in significant post-operative weight-loss without further interventions

Background. Increasing number of studies investigating surgical patients have reported longer length of stay (LOS) in hospital after an operation with higher ASA grades. However, the impact of Body Mass Index (BMI) on LOS in hospital post Total Knee Replacement (TKR) remains a controversial topic with conflicting findings in reported literature. In our institution, we recently adopted a weight reduction program requiring all patients with raised BMI to participate in order to be considered for elective TKR. Objectives. This has prompted us to investigate the impact BMI has on LOS compared to the more established impact of ASA grade on patients following Primary TKR. Methods. A retrospective analysis was conducted on all elective primary TKR patients between November 2013 and May 2014. LOS was compared in BMI groups <30, 30–40 and >40 and ASA grades 1–2 and 3–4. ANOVA and independent t-test were used to compare mean LOS between BMI groups and ASA grades, respectively. Results. Two hundred and thirty six TKR were analysed. Mean LOS in BMI groups <30, 30–40 and >40 were 6.0, 6.4 and 6.0 days, respectively (p = 0.71). Mean LOS in ASA groups 1–2 and 3–4 were 5.8 and 7.6, respectively (p < 0.01). Conclusions. In patients undergoing primary TKR, ASA grade is a better predictor of LOS than BMI. Our data further adds to the evidence that high BMI alone is not a significant factor in prolonging LOS after a primary TKR. This should be taken into account when allocating resources to optimise patients for surgery. Level of evidence. III - Evidence from case, correlation, and comparative studies

Obesity is considered a risk factor to a successful outcome in total knee arthroplasty. The prevalence of obesity is causing concern as risks associated with obesity are well documented and the incidence of obesity is increasing in the Australian population. Previous studies have not reached a consensus on the relationship of BMI and short term outcomes of total knee arthroplasty. The aims of this study were to evaluate the relationship between BMI and the degree of flexion achieved at discharge and to determine the influence of BMI on pre and postoperaive range of motion, duration of surgery, analgesia requirements and duration of stay. Obesity is defined as a body mass index (BMI) of greater than 30 KG/m2. 120 consecutive patients were recruited from patients presenting for total knee arthroplasty (TKA) to two hospitals. They were classified into one of four groups based on their BMI. All patients were assessed pre and postoperatively by the surgical team. Data was collected on type of implant used, duration of surgery, type of anaesthetic, analgesia requirements and length of stay. Knee society scores were collected pre and postoperatively. Three to six month follow-up was conducted by the surgical team to record flexion, ROM and KSS. Statistical analysis was performed using statistical software. 120 patients were available for the study with 61 (50.8%) being classified as obese and 6 patients classified as morbidly obese. (BMI > 40). The average preoperative flexion results were 112.1 degrees (BMI 18.5 to 14.9), 114.0 degrees (BMI 25 to 29.9), 107.0 degrees (BMI 30 and above), while the postoperative flexion prior to discharge was 85 (BMI 18.5 to 24.9), 90.3 (BMI 25 29.9) and 88.3 (BMI 30 or above). The obese patients had a lower ROM preoperatively but there was no Significant difference at discharge. Patients with a BMI of 25–29.9 used the least amount of analgesia and had the fastest surgery time. They also spent the least amount of time in hospital. (6.3 days) Patients classified as clinically obese (BMI 30 and above) recorded the lowest KSS. As BMI increases the postoperative functional knee score decreases but there is no Significant difference at discharge and 3–6 months postoperatively. The increasing prevalence of obesity in the Western world suggests that a Significant proportion of surgical patients will be in the obese or morbidly obese catergory. This studty suggests that BMI alone does not influence the short term outcomes of TKA. The poorer long term outcomes in TKA may be related to other factors. Further research may be appropriate

Management of the pathologic long-head biceps tendon remains controversial. Biceps tenotomy is a simple intervention but may result in visible deformity and subjective cramping. Comparatively, biceps tenodesis is technically challenging, and has increased operative times, and a more prolonged recovery. The purpose of this study was to determine the incidence of popeye deformity following biceps tenotomy versus tenodesis, identify predictors for developing a deformity, and compare subjective and objective outcomes between those that have one and those that do not. Data for this study were collected as part of a randomized clinical trial comparing tenodesis versus tenotomy in the treatment of lesions of the long head of biceps tendon. Patients 18 years of age or older with an arthroscopy confirmed biceps lesion were randomized to one of these two techniques. The primary outcome measure for this sub-study was the rate of a popeye deformity at 24-months post-operative as determined by an evaluator blinded to group allocation. Secondary outcomes were patient reported presence/absence of a popeye deformity, satisfaction with the appearance of their arm, as well as pain and cramping on a VAS. Isometric elbow flexion and supination strength were also measured. Interrater reliability (Cohen's kappa) was calculated between patient and evaluator on the presence of a deformity, and logistic regression was used to identify predictors of its occurrence. Linear regression was performed to identify if age, gender, or BMI were predictive of satisfaction in appearance if a deformity was present. Fifty-six participants were randomly assigned to each group of which 42 in the tenodesis group and 45 in the tenotomy group completed a 24-month follow-up. The incidence of popeye deformity was 9.5% (4/42) in the tenodesis group and 33% (15/45) in the tenotomy group (18 male, 1 female) with a relative risk of 3.5 (p=0.016). There was strong interrater agreement between evaluator and patient perceived deformity (kappa=0.636; p<0.001). Gender tended towards being a significant predictor of having a popeye with males having 6.6 greater odds (p=0.090). BMI also tended towards significance with lower BMI predictive of popeye deformity (OR 1.21; p=0.051). Age was not predictive (p=0.191). Mean (SD) satisfaction score regarding the appearance of their popeye deformity was 7.3 (2.6). Age was a significant predictor, with lower age associated with decreased satisfaction (F=14.951, adjusted r2=0.582, p=0.004), but there was no association with gender (p=0.083) or BMI (p=0.949). There were no differences in pain, cramping, or strength between those who had a popeye deformity and those who did not. The risk of developing a popeye deformity was 3.5 times higher after tenotomy compared to tenodesis. Male gender and lower BMI tended towards being predictive of having a deformity; however, those with a high BMI may have had popeye deformities that were not as visually apparent to an examiner as those with a lower BMI. Younger patients were significantly less satisfied with a deformity despite no difference in functional outcomes at 24 months. Thus, biceps tenodesis may be favored in younger patients with low BMI to mitigate the risk of an unsatisfactory popeye deformity

Background. This study aimed to investigate the effect of body mass index (BMI) on functional outcome following hip preservation surgery using the U.K. Non-Arthroplasty Hip Registry (NAHR). Methods. Data on adult patients who underwent hip arthroscopy or periacetabular osteotomy (PAO) between January 2012 and December 2018 was extracted from the UK Non-Arthroplasty Hip Registry dataset allowing a minimum of 12 months follow-up. Data is collected via an online clinician and patient portal. Outcomes comprised EuroQol-5 Dimensions (EQ-5D) index and the International Hip Outcome Tool 12 (iHOT-12), preoperatively and at 6 and 12 months. Results. A total of 6,666 patients were identified with BMI data available in 52%, comprising 3,220 arthroscopies and 277 PAO. Patients were divided into WHO groups: <25kg/m. 2. (n=1,745 (49.8%)), 25–30kg/m. 2. (n=1,199 (34.2%)), and ≥30kg/m. 2. (n=562 (16.0%)). Patients with higher BMI tended to be older. Pre-operative, 6 and 12-month follow-up were available for 91%, 49% and 45% of cases respectively. Higher BMI was associated with significantly poorer baseline, 6- and 12-month outcomes (12-month mean iHOT-12 score: <25kg/m. 2. = 62.3 (95%CI 60.4 to 64.3), 25–30kg/m. 2. = 57.3 (95%CI 55.0 to 59.7), ≥30kg/m. 2. = 54.7 (95%CI 51.1 to 58.2)). However, all groups saw similar and statistically significant improvement in pre- vs post-op scores (mean 12-month iHOT-12 gain: <25kg/m. 2. = +27.1 (95%CI 25.1 to 29.0), 25–30kg/m. 2. = +26.5 (95%CI 24.0 to 29.0), ≥30kg/m. 2. = +26.8 (95%CI 23.2 to 30.4), between-group p = 0.9). EQ-5D outcomes followed the same trend. Modelling for age, sex and procedure we found no significant difference in 12-month iHOT-12 gain between BMI groups. Conclusion. Whilst obese patients started from, and achieved lower post-operative raw functional scores, all BMI groups saw similar and significant degrees of improvement in functional outcome post-operatively. Obesity should not be considered a contraindication to hip preservation surgery

Introduction. High BMI has been classically regarded as a contraindication for unicompartmental knee arthroplasty (UKA) as it can potentially lead to poor clinical outcomes and a higher risk of failure. In recent years, UKA has increased in popularity and, as a result, patient selection criteria are beginning to broaden. However, UKA performed manually continues to be technically challenging and surgical technique errors may result in suboptimal implant positioning. UKA performed with robotic assistance has been shown to improve component positioning, overall limb alignment, and ligament balancing, resulting in overall improved clinical outcomes. The purpose of this study is to examine the effect of high BMI in patients receiving UKA with robotic assistance. Methods. 1007 patients (1135 knees) were identified in an initial and consecutive multi-surgeon multi-center series receiving robotically assisted medial UKA, with a fixed bearing metal backed onlay tibial component. As part of an IRB approved study, every patient in the series was contacted at a minimum two year (±2 months) follow up and asked a series of questions to determine implant survivorship and satisfaction. 160 patients were lost to follow up, 35 patients declined to participate, and 15 patients were deceased. 797 patients (909 knees) at a minimum two year follow up enrolled in the study for an enrollment rate of 80%. 45% of the patients were female. The average age at time of surgery was 69.0 ± 9.5 (range: 39–93). BMI data was available for 887 knees; the average BMI at time of surgery was 29.4 ± 4.9. Patients were stratified in to five categories based on their BMI: normal (< 25; 16%), overweight (25–30; 46%), obese class I (30–35; 25%), obese class II (35–40; 11%) and obese class III (>40; 2%). Results. Across all BMI groups, nine knees were reported as revised at two years post-operative yielding a two year revision rate of 0.99%, 4 in the overweight group, 2 in the obese class I group and 3 in the obese class II group. There was no significant difference in the rate of revision between the BMI groups (c. 2. (4, N = 887) = 6.04, p = 0.20). Of the 3 revisions for tibial component loosening, one occurred in the overweight group, one in the obese group and one in the morbidly obese group. The overall patient satisfaction rate for the entire population was 92% with the following distribution: normal: 92%, overweight: 93%, obese class I: 92%, obese class II: 87% and obese class III: 83%. While the most severely obese patients tended to be less satisfied, this was not statistically significant between the groups (c. 2. (4, N = 887) = 5.12, p = 0.27). Conclusion. These results suggest that BMI does not effect the survivorship or the satisfaction of patients undergoing robotically assisted UKA. Advancement in UKA implant designs and improvements in surgical technique may help to broaden indications and patient selection for UKA. This study will continue to track patients mid to long term to determine the longer term effect of robotically assisted UKA on high BMI patients

A number of studies have reported longer length of hospital stay (LOS) after surgery in patients with higher ASA grades. The impact of Body Mass Index (BMI) on LOS after Total Hip Replacement (THR) remains unclear with conflicting findings in reported literature. In our hospital we strongly encourage all patients with a raised BMI to participate in a weight reduction programme prior to surgery. This prompted us to investigate the impact BMI has on LOS compared to the more established impact of ASA grade. A retrospective analysis was conducted on all elective primary THR patients between 11/2013 to 02/2014. LOS in BMI groups <30, 30–39 and ≥40 and ASA grades 1–2 and 3–4 was compared. Where appropriate, independent t-test and non-parametric Mann-Whitney test were used to predict significance. 122 THR were analysed. Mean LOS in BMI groups <30, 30–39 and ≥40 were 5.6, 6.2 and 8.0 days, respectively. This was not predicted significant (p=0.7). Mean LOS in ASA groups 1–2 and 3–4 were 5.2 and 9.3, respectively. This was predicted significant (p-value < 0.01). In patients undergoing primary THR, ASA grade is a better predictor of LOS than BMI. Our data adds to the evidence that high BMI alone is not a significant factor in prolonging LOS after a primary THR. This should be taken into account when allocating resources to optimise patients for surgery

Introduction. Total knee arthroplasty (TKA) implant systems offer a range of sizes for orthopaedic surgeons to best mimic the patient's anatomy and restore joint function. From a biomechanical perspective, the challenge on the TKA implants is affected by two factors: design geometry and in vivo load. Larger geometry typically means more robust mechanical structure, while higher in vivo load means greater burden on the artificial joint. For an implant system, prosthesis geometry is largely correlated with implant size, while in vivo load is affected by the patient's demographics such as weight and height. Understanding the relationships between implant size and patients' demographics can provide useful information for new prosthesis design, implant test planning, and clinical data interpretation. Utilizing a manufacturer supported clinical database, this study examined the relationships between TKA patient's body weight, height, and body mass index (BMI) and the received implant size of a well-established implant system. Methods. A multi-site clinical database operated by Exactech, Inc. (Gainesville, FL, USA) was utilized for this study. The database contains patient information of Optetrak TKA implant recipients from over 30 physicians in US, UK, and Colombia since 1995. Nine implant sizes (0, 1, 2, 2.5, 3, 3.5, 4, 5 and 6) are seen in the database, while size 0 was excluded due to very low usage. Taking primary TKA only, a total of 2,713 cases were examined for patient's body weight, height, BMI, and their relationships with the implant size. Results. Both patient's weight and height strongly correlate with implant size (R. 2. »0.95 for both parameters with a linear regression). On average, the increase of one implant size corresponds to an increase of 7.4 kg in patient's weight and 7.0 cm in patient's height (Figure 1). However, there is almost no dependency between patient's BMI and implant size (R. 2. <0.05), and the regression line is almost flat (k=-0.08) (Figure 1). Discussion. Based on the Exactech database, this study revealed that TKA patients' weight and height increase close-to-linearly with implant size, but BMI stays fairly constant. These relationships are not all intuitive mathematically, and are likely simplified representations of higher order functions within the particular variable ranges. The most interesting finding was the independence of BMI on implant size, which provides a favorable validation of the geometry design and size selection of the Optetrak implant system. BMI (kg/m. 2. ) has the same unit dimension as stress (N/m. 2. ) excluding the constant g (9.8 N/kg). Since implant geometry is generally proportional to patient height, and joint force is generally proportional to patient weight, the mechanical stress imposed on the implant would be generally proportional to patient's BMI. The fact that BMI stays constant across sizes indicates that the implant system would experience a similar level of stress across all sizes, which has been previously observed in femorotibial contact stress analyses on the Optetrak system. This study showed that a heavier TKA patient statistically tends to receive a larger implant which, depending on implant design, will provide larger contact area and compensate for the higher load

Abstract. Introduction. Medial fix bearing unicompartmental knee replacement (UKR) designs are consider safe and effective implants with many registries data and big cohort series showing excellent survivorship and clinical outcome comparable to that reported for the most expensive and surgically challenging medial UKR mobile bearing designs. However, whether all polyethylene tibial components (all-poly) provided comparable results to metal-backed modular components during medial fix bearing UKR remains unclear. There have been previous suggestions that all-poly tibia UKR implants might show unacceptable higher rates of early failure due to tibial component early loosening especially in high body max index (BMI) patients. This study aims to find out the short and long-term survival rate of all-poly tibia UKR and its relationship with implant thickness and patient demographics including sex, age, ASA and BMI. Material and Methods. we present the results of a series of 388 medial fixed bearing all-polly tibia UKR done in our institution by a single surgeon between 2007–2019. Results. We found out excellent implant survival with this all-poly tibia UKR design with 5 years survival rate: 96.42%, 7 years survival rate: 95.33%, and 10 years survival rate: 91.87%. Only 1.28% had early revision within 2 years. Conclusion. Fixed bearing medial all-poly tibia UKR shows excellent survivor rate at 2, 5, 7 and 10 years follow up and the survival rate is not related with sex, age, BMI, ASA grade or implant thickness. Contrary to the popular belief, we found out that only 1.71% of all implants was revised due to implant loosening

Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown. 1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant between 2011–2017 at three European and seven US sites. Of 2,003 (97.3%) TKAs in 1,644 patients with BMI data: average age 64.5 years; 58.4% females; average BMI 32.5 kg/m2; 13.4% had BMI ≥ 40 kg/m2. Subjects with BMI ≥ 40 kg/m2 had longest length of hospital stay (LOS) at European sites; LOS similar at US sites. Subjects with BMI ≥ 40 kg/m2 (P=0.0349) had longest surgery duration. BMI ≥ 40 kg/m2 had more re-hospitalizations or post-TKA reoperations than BMI < 40 kg/m2 (12.7% and 9.2% at five-year post-TKA, P<0.0495). Surgery duration and long-term complication rates are higher in patients with BMI ≥ 40 kg/m2, but device revision risk is not elevated

BACKGROUND. Some papers recently reported conflicting results on implant survivorship in all-poly tibial UKRs. Furthermore, the influence of BMI on this specific implant survivorship remains unclear, since existing reports are often based on small series of non-consecutive patients with different follow up durations, enabling to generate meaningful conclusions. PURPOSE. To determine the 10-years survival rate of an all-poly tibial UKR in a large series of consecutive patients and to investigate whether a correlation exists between a higher BMI and an increased risk of revision for any reason. METHODS. A retrospective evaluation of 273 patients at 6 to 13 years of follow-up was performed. Clinical evaluation was based on KSS and WOMAC scores. Subjective evaluation was based on a VAS for pain self-assessment. Radiographic evaluation was performed by 3 independent observers. A Kaplan-Meier survival analysis was performed assuming revision for any reason as primary endpoint. Reason of revision was determined basing on clinical and radiographic data. RESULTS. The 10-years implant survivorship was 90.8%. Twenty-five revisions (9.2%) were performed and aseptic loosening of the tibial component was the most common failure mode (11 cases, 4%). No significant correlation was identified between failure and patients'BMI. Mean post-operative results for KSS and WOMAC score were 87.0 (st.dev. 14.6) and 87.37 (st.dev. 11.48), respectively. VAS showed a significant improvement (p<0.0001) respect to pre-operative condition. CONCLUSIONS. Unlike some recent reports, this study demonstrated a satisfactory 10-years implant survivorship using an all-poly tibial UKR. A higher BMI does not reduce survival rate at 6 to 13 years of follow-up

Purpose. Weight loss is often advised to our patients and considered to make a substantial difference in most musculoskeletal symptoms. Patients with end stage ankle arthrosis have severe pain, diminished health related quality of life, and limited physical function. They frequently refer to increased weight as a simple indicator of decline in their quality loose weight. Patients assume that weight loss will follow after surgery secondary to increased activity with reduced pain and disability. Method. Changes in the body mass index, mental and physical component of SF36 and Ankle Scale Osteoarthritis of 145 overweight and obese patients after ankle surgery were assessed up to five year after surgery with a mean of 37.1 month follow up from 2002 to 2009. Results. The Ankle Osteoarthritis Scale and Physical component of SF36 significantly improved, by a mean of 34.8, 9.8, respectively after ankle surgery but there was not significant change in Body mass index. Conclusion. Pain and disability of end stage ankle arthritis usually resolve gradually within one and two year after surgery but body mass index changes was insignificant in five year period. In fact following successful ankle fusion or replacement, 1/3 of our patients gained 1 unit BMI or more, 1/3 lost one unit BMI or more and 1/3 remained within one unit of their pre op BMI. This suggests that obesity is a multifactorial and an independent disease

Introduction: Obesity is a risk factor to develope knee OA. Patients who are obese often consider their disabling joint disease as a cause for their increased weight. The purpose of this study is to evaluate the changes of weigth and BMI in obese patients after TKA. Methods: 102 obese patients who underwent TKA between January 2002 and December 2003 were evaluated. They were followed for a mean duration of 35 months. Data about age, height, weight, BMI, hypertension, diabetes, NSAIDs and crutches were collected preoperative and at the end of follow-up. Statystical analysis was done using SPSSv11.5. Results: Mean age was 69.8 y.o.. The average height was 157 cm. 24 were men and 78 women. Mean preoperative weight was 86.7 Kgs and at the end of follow-up was 87.3. BMI rose from 35.1 to 35.3. 90% recognized a better quality of life. 12.2% have a better control of their hypertension.30% needs NSAIDs and 4% uses crutches. Conclusions: Obesity leads to an important number of Total Joint Replacement, specially TKA. Apparently it haven’t a worse outcome. Patients doesn’t loose weight after TKA, someones gain it. Knee OA can’t be considered as a cause of overweight.Obesity should be treated as an independent disease

Painful foot and ankle joints are often pointed out as an impeding factor for lack of mobility and weight reduction. There is an assumption that weight loss will occur after their surgery due to increased mobility. The current study aimed to evaluate the effect of surgery on post-operative body mass index (BMI) in patients who underwent mid-foot or hind-foot arthrodesis. Our secondary aim was to look at the effect of sex, pre-operative obesity and good pain relief (AOFAS> 80) on post-operative BMI. All patients who underwent mid-foot and hind-foot arthrodesis between April 2005 and November 2006 were identified from the operating theatre records. Each patient’s BMI recorded pre-operatively was compared with that recorded at a minimum of 6 months postoperatively using the paired Student’s t-test. There were 35 eligible patients. 3 patients were excluded because of multiple trauma and 1 patient died during the period of study. We had 31 patients with 33 procedures with a mean age of 61 years (range 41–80). There were 18 females and 13 males. It was found that there was a mean increase of BMI by 0.25 (95%CI of −.95 to.44; p-value=0.47). It was noted that BMI of patients in obese group (BMI> 30) increased post-operatively by 0.07 (95%CI of −1.52 to 1.66; p-value=0.92). This study highlights the fact that there is no significant effect on BMI in obese patients after successful fusion surgery. The post-operative BMI is neither significantly affected by sex nor quality of pain relief

Introduction: Obesity has become a major public health epidemic, with recent reports citing that 22% of English men and 24% of women are clinically obese. Painful foot and ankle joints are often pointed out as an impeding factor for lack of mobility and weight reduction. There is an assumption that weight loss will occur after their surgery due to increased mobility. The current study aimed to evaluate the effect of surgery on post operative body mass index (BMI) in patients who underwent mid-foot or hind-foot arthrodesis. Patients and Method: All patients who underwent mid-foot and hind-foot arthrodesis under the care of senior author from April 2005 to Nov. 2006 were identified from the operating theatre records. In total 33 procedures were done in 31 patients. Each patient’s BMI recorded pre-operatively was compared with that recorded at a minimum of 6 months postoperatively using the paired Student’s t-test. Analysis of the data was also conducted by stratifying pre-operative BMI, good pain relief (i.e AOFAS> 80), sex and fusion site. Results: It was found that there was a mean increase of BMI by 0.25 (95% CI of −0.95 to 0.44) with p-value of 0.47. It was noted that BMI of patients in obese group increased post-operatively by 0.07 (95% confidence interval of −1.52 to 1.66) with p-value of 0.9. Discussion: This study highlights the fact that there is no significant effect on BMI in obese patients despite significant increase in mobility and pain levels after mid-foot and hind-foot arthrodesis. The change in BMI after fusion surgery is not significantly effected by sex nor quality of pain relief

Introduction. Stiffness after total knee arthroplasty is a common occurrence. Despite its prevalence, little is known as to which patients are at risk for poor range of motion after total knee arthroplasty. The purpose of this study was to determine the risk factors for manipulation under anesthesia (MUA) after total knee arthroplasty (TKA). Methods. Using a single institution registry, 160 patients who underwent a manipulation under anesthesia after total knee arthroplasty between 2007 and 2013 were retrospectively evaluated. Each patient was 1:1 matched by age, gender and laterality to a control group of 160 patients who did not require MUA after TKA. Risk factors for MUA were assessed, and included medical co-morbidities, BMI, prior operations, and preoperative range of motion. Results. There were 160 patients in each group, 48 males and 112 females. Patients who required a MUA after TKA had a significantly higher percentage of overweight patients with a BMI >25 (88% vs 76%, p=0.01, Odds ratio=2.18), and previous surgery including arthroscopy (60% vs 33%, P < 0.0001, Odds ratio=3.12). Patients that underwent an MUA had a higher but not significant prevalence of depression and anxiety (22% vs. 16%, p=0.20, Odds Ratio=1.44) and diabetes (15% vs. 8%, p=0.058, Odds Ratio=2.0). Average ROM was 3–110° (Range −10–130°) and 6–102° (Range 0–140°) in the MUA and control groups respectively. In the MUA group, 29% of patients had pre-operative flexion less than 90 degrees pre-operatively compared to 3% in the control group (p=0.02, Odds Ratio=6.6). While the average preoperative range of motion did not differ between the groups, there were a larger percentage of patients with severe limitations in range of motion who ended up needing a MUA after TKA compared to controls. Conclusion. Patients with increased BMI, preoperative range of motion less than 90°, and a history of prior operations should be counseled on the increased risk of requiring a MUA after TKA

The outcome and survivorship of osteotomy for medial compartment osteoarthritis are closely correlated to the changes in the weight bearing axis. Questions remain over the optimal correction when undertaking medial unicompartmental knee replacement (UKR). Prospective data was collected on 50 patients (30F:20M) undergoing fixed bearing medial UKR which included pre-operative and 12 month Oxford Knee Scores and pre and post-operative weight-bearing long-leg radiographs. The weight bearing axis was measured from the centre of the femoral head to the mid-point of the talus. The point at which this axis crossed the tibial plateau was expressed as a percentage of the width of that plateau - 0 (medial cortex) to 100% (lateral cortex). Regression method and correlation coefficients were used to assess the relationship between the response and variables. A significant correlation was seen between the 12 month score and the change in axis, which was maintained when the pre-operative score was adjusted for (p = 0.043 and 0.046 respectively). Larger changes in scores were seen with larger changes in axis (p = 0.046) when the pre-operative axis was adjusted for. Higher BMIs reported worse scores at 12 months (p = 0.022) and a smaller overall change in score one year post-operatively (p = 0.037). This significance was improved when the pre-operative scores were adjusted (p = 0.017 and 0.017 respectively). Proximity of correction of axis to the assumed contralateral normal was weakly correlated (p = 0.049) to the 12 month score, especially when BMI was corrected for. These results suggest that the weight bearing axis and BMI do play a significant role in early patient outcomes following fixed bearing unicompartmental knee replacement

Purpose: The growing trend of morbidly obese (BMI 40+) patients requiring a total joint replacement is becoming major concern in total knee Arthroplasty (TKA). The purpose of this study was to investigate the affects that BMI may have on implant longevity and clinical patient outcome using historical patient data. Method: A consecutive cohort of 3083 TKA’s in 2048 patients since 1995 (minimum 2 years follow-up) were evaluated. Pre-operative scores, latest scores, and change in clinical outcome scores (KSCRS, SF12, WOMAC) were analyzed using ANOVA and Kaplan-Meier (K-M) survivorship was determined. Results: K-M cumulative survival at 10 years by BMI group was 0.951±0.033 for Normal and Underweight (< 25, n=277), 0.944±0.024 for Overweight (25–29.9, n=915), 0.882±0.032 for Obese (30–39.9, n=1460) and 0.843±0.076 for Morbidly Obese (40+, n=352). Cumulative revision rates were 1.8% for Normal and Underweight, 1.9% for Overweight, 2.9% for Obese and 2.8% for Morbidly Obese. All pre-operative clinical scores were significantly different between the Morbidly Obese and all other BMI groups (p< 0.05), with the non-morbidly obese having higher scores in all cases. Significant difference was found in the change in WOMAC domain scores and the KSCRS knee score (p< 0.05) between the morbidly obese group and all other BMI groups, with the morbidly obese having the greatest improvement in all domains. Conclusion: The morbidly obese patient cohort (BMI > 40) undergoing TKA demonstrated the most significant improvement in clinical outcome scores; however also had the lowest cumulative 10 year survivorship. This risk/benefit information is important in pre-operative discussions with this challenging, and increasingly prevalent, patient population

There is mixed evidence in the literature regarding increasing age, ASA and BMI as risk factors for surgical site infection in orthopaedic surgery. To investigate the matter further, we examined 1055 wounds in 1008 patients in the Department of Trauma and Orthopaedic Surgery at University College London Hospital between 2000 and 2006. All patients with a minimum two-night stay were included. Data was collected by four designated research nurses. The age, height, weight and ASA status of each patient was recorded. All wounds were classified using ASEPSIS. This is a quantitative wound scoring method which is a summation of scores calculated from visual wound characteristics and the clinical consequences of infection. Our results showed a strong linear association between age and ASEPSIS scores. Single variable regression analysis showed a t value of 3.32 and p value of 0.001. A similar linear association was seen between ASA grading and ASEPSIS scores. Single variable regression analysis showed a t value of 2.75 and p value of 0.006. The association between BMI and ASEPSIS scores was markedly different from that seen with age and ASA. The graph was U-shaped with patients with a BMI of 25-30 having the lowest average ASEPSIS scores. Patients with a lower and a higher BMI had higher average ASEPSIS scores. Single variable regression analysis was not significant since the relationship between BMI and ASEPSIS scores is not linear. In conclusion, there are clearly defined patient groups who are at increased risk of developing a surgical site infection: older patients, patients with a higher ASA, and patients with both a low and high BMI. These patients should be targeted to reduce overall infection rates. This can be achieved by ensuring adequate antibiotic prophylaxis, having a low threshold to treat suspected infection and arranging regular follow-up

Background: Among patients undergoing total hip arthroplasty (THA) 24–36% are obese. The most important long-term complication is periprosthetic osteolysis. While patient activity, implant type and quality of fixation are known risk factors for osteolysis, the literature concerning obesity is sparse and controversial. Our objective was to evaluate the influence of obesity on femoral osteolysis five and ten years after primary THA with a cemented stem. Methods: Prospective cohort study conducted between 1996 and 2003 among patients undergoing THA (uncemented cup, cemented stem, 28mm head and ceramic-polyethylene bearing surface) inserted with a third generation cementing technique. All patients were seen at either five or ten years, with information regarding BMI and activity, and with radiographic follow-up. BMI was evaluated in three and four categories (< 25, 25–29.9 (reference category), 30–34.9 and ≥35 kg/m. 2. ). Activity was assessed using the University of California, Los Angeles (UCLA) activity scale (1–10 points). Main outcome was the radiographic assessment of femoral osteolysis. Secondary outcomes were polyethylene wear and revision for aseptic loosening. Results: We included 503 THAs in 433 patients. Of those 241 THAs (48%) were seen at five years and 262 (52%) at ten years. Osteolytic lesions were identified in forty-four cases, twenty-four in 181 normal weight patients (13.3%), eleven in 205 overweight (5.4%), seven in ninety-six obese class I (7.3%), and two in twenty-one obese class II patients (9.5%). Activity was highest in normal weight patients (mean UCLA score 5.5, ±2.0) and lowest in patients obese class II (mean UCLA score 4.8, ±1.7). Univariate as well as multivariate logistic regression analysis adjusting for activity, cementing quality, age, and sex did not show an increased risk of osteolysis in obese compared to overweight patients (adjusted OR 1.4, 95% CI 0.6; 3.7). A significantly higher risk was found in normal weight patients (adjusted OR 2.6, 95% CI 1.2; 5.7). Total mean polyethylene wear was significantly lower in obese compared to normal/overweight patients (p=0.024). Revision for aseptic loosening of the stem was necessary in 4 patients (3 normal weight patients and 1 overweight patient). Conclusions: We did not find an increased risk for femoral osteolysis or revision for aseptic loosening in obese patients five and ten years after primary THA with a cemented stem

Study design: Prospective cohort study. Objective: To investigate association between recovery from low back pain (LBP) and body mass index (BMI) in patients with LBP undergoing physiotherapy. Introduction: The relationship between obesity and LBP has long been debated. There are no published studies examining the influence of BMI on recovery from LBP. Methods: One hundred and forty patients with chronic LBP and no neurological deficit underwent a back-specific physiotherapy programme. BMI and recovery parameters such as pain intensity (visual analogue scale scores), and self-experienced impairment and disability scores were measured. The range of motion of the lumber spine was also recorded. These variables were compared pre and post treatment. Statistical analysis was performed using paired t tests, Spearman’s rank correlation coefficients and ANCOVA. Results: Mean age was 38 years (range 18–67) with 62% males and 38% females. The treatment resulted in significant improvements in all the recovery parameters (P < 0.005, paired t test). No significant association was detected between the BMI of subjects and % changes in pain intensity, self-experienced impairment and disability, and range of motion of the lumbar spine. A comparative analysis of the after treatment recovery parameter scores in normal (BMI ≤24.9), overweight (BMI 25–29.9) and obese (BMI ≥ 30) revealed no significant differences in the mean pain intensity and mean self-experienced impairment and disability scores. Conclusion: Although a BMI within normal range is desirable for prevention of many health conditions including LBP, it does not influence the overall recovery from low back pain in patients undergoing physiotherapy treatment

Introduction. We conducted a study of 312 patients undergoing primary hip and knee arthroplasty in 2005. The aim was to identify the correlation between length of stay, ASA (American society of Anaesthesiologist) grade and BMI (Body Mass Index). Method and materials. 312 patients underwent hip and knee arthroplasty in 2005. ASA grade for surgery was documented by the anaesthetist and BMI by the nurses. 67 patients had inadequate documentation. SPSS software was used for analysis. Results. Of the 245 patients; 35 had ASA grade 1, 144 had ASA grade 2, 64 had ASA grade 3 and 2 had ASA grade 4. Mean length of stay for ASA grade 1 was 6.8 days, ASA grade 2 was 9.75 days, ASA grade 3 was 12.5 days and ASA grade 4 was 13.5 days. There was significant positive correlation (p < 0.01) between the ASA grade and post-operative length of stay. BMI was graded as I (<18.5), II (18.5-24.9), III (25-29.9) and IV (>30). There was no correlation (Pearson's correlation coefficient = 0.184) between BMI and post-operative length of stay. Conclusion. As the ASA grade increases the length of stay in hospital increases. ‘Cherry picking’ of ASA grade I and II patients by the ISTC will increase the average length of stay in NHS hospitals resulting in increased cost. Length of stay on its own is not a good indicator of hospital performance

Purpose: There remains some debate over the impact of obesity on complications and function following total joint replacement. The purpose of this study was to examine the relationship between BMI, self reported complications, function and satisfaction using data from a large prospectively collected dataset. Method: A total of 5364 procedures with complete one year post operative data were obtained from a Canadian joint replacement registry for analysis. Self reported complications after one year included re-operation, DVT, PE, dislocation and infection requiring antibiotics. BMI was classified as either non-obese (BMI30kg/m2). Satisfaction was collapsed into dichotomous categories: satisfied or unsatisfied. Pre and post operative scores from the Oxford 12 were also included. Results: The mean age of the total hip replacement (THR) group was 67.1 yrs (+/−11.8) with a mean BMI of 29.8 (+/−6.4). The total knee replacement (TKR) group’s mean age was 68.2 yrs (+/−9.99) with a mean BMI of 33.0 (+/−7.0). Ninety percent (90.6%) of THR patients were satisfied one year after surgery compared to only 81.9% of TKR patients (p< 0.0001). For TKR patients, larger BMI was associated with both satisfaction and self-reported complications; obese patients reported being satisfied 82.4% of the time versus non-obese at 76.9% (p=0.037). Complication rates for obese TKR patients were 11.9% and 7.9% for non-obese (p=0.064). For THR patients, a similar relationship did not exist between BMI and satisfaction; however, it was observed for complications. Obese patients reported a complication rate of 7.4% versus 4.2% (p=0.02) for non-obese. Improvements in Oxford 12 scores were noted across all groups; mean improvement was 22 points in the THR group and 15 points in the TKR group, irrespective of BMI. Improvements in Oxford 12 scores were associated with complications; THR patients reporting complications showed mean improvements of 17 points versus 23 for those who did not (p< 0.0001). TKR patients reporting complications had mean improvements of 10 points versus16 for those who did not (p< 0.0001). Satisfaction was also related to Oxford 12 score; THR patients who were unsatisfied demonstrated an Oxford 12 improvement of only 9 points versus 24 points for the satisfied patients (p< 0.0001). Unsatisfied TKR patients demonstrated an improvement of only 4 points compared to 18 points for satisfied patients, (p< 0.0001). Conclusion: THR patients were younger and more satisfied than TKR patients. There appears to be a positive relationship between BMI and complication rates for both TKR and THR. A larger BMI was related to increased satisfaction in TKR, it was unrelated in THR. Satisfaction was related to degree of functional improvement which, in turn, was curtailed by complications. It is therefore prudent to advise patients to reduce BMI prior to surgery to mitigate complications; however superior or equivalent satisfaction rates and positive functional improvement can be expected post surgery

Two big problems exist with the all polyethylene cemented tibial component; the polyethylene and the cement. The polyethylene is too weak and flexible to bear high tibial load, so it deforms and loosens. The interface stresses are too high when two flexible structures are poorly bonded and heavily loaded.

Modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80's for versatility and to facilitate screw fixation for cementless implants. These designs allow exchange of various polyethylene thicknesses, and aids the addition of stems and wedges. Other advantages include the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. Several studies have documented the high failure rate of isolated polyethylene exchange procedures, because technical problems related to the original components are left uncorrected. However, revision for wear is the simplest revision ever!

Since the late 1980's the phenomena of polyethylene wear and osteolysis have been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear. There is some association with the widespread use of both cementless and cemented modular tibial designs. Improved polyethylene attachment is the answer even if a screw, a wire, or a pin is needed. Do not abandon the modular tibia.

Aims. Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m. 2. ). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m. 2. to examine whether this is supported. Methods. This single-centre study compared 169 consecutive patients with severe obesity (BMI ≥ 40 kg/m. 2. ) (mean age 65.2 years (40 to 87); mean BMI 44.2 kg/m. 2. (40 to 66); 129/169 female) undergoing unilateral TKA to a propensity score matched (age, sex, preoperative Oxford Knee Score (OKS)) cohort with a BMI < 40 kg/m. 2. in a 1:1 ratio. Demographic data, comorbidities, and complications to one year were recorded. Preoperative and one-year patient-reported outcome measures (PROMs) were completed: EuroQol five-dimension three-level questionnaire (EQ-5D-3L), OKS, pain, and satisfaction. Using national life expectancy data with obesity correction and the 2020 NHS National Tariff, QALYs (discounted at 3.5%), and direct medical costs accrued over a patient’s lifetime, were calculated. Probabilistic sensitivity analysis (PSA) was used to model variation in cost/QALY for each cohort across 1,000 simulations. Results. All PROMs improved significantly (p < 0.05) in both groups without differences between groups. Early complications were higher in BMI ≥ 40 kg/m. 2. : 34/169 versus 52/169 (p = 0.050). A total of 16 (9.5%) patients with a BMI ≥ 40 kg/m. 2. were readmitted within one year with six reoperations (3.6%) including three (1.2%) revisions for infection. Assuming reduced life expectancy in severe obesity and revision costs, TKA in patients with a BMI ≥ 40 kg/m. 2. costs a mean of £1,013/QALY (95% confidence interval £678 to 1,409) more over a lifetime than TKA in patients with BMI < 40 kg/m. 2. In PSA replicates, the maximum cost/QALY was £3,921 in patients with a BMI < 40 kg/m. 2. and £5,275 in patients with a BMI ≥ 40 kg/m. 2. . Conclusion. Higher complication rates following TKA in severely obese patients result in a lifetime cost/QALY that is £1,013 greater than that for patients with BMI < 40 kg/m. 2. , suggesting that TKA remains a cost-effective use of healthcare resources in severely obese patients where the surgeon considers it appropriate. Cite this article: Bone Joint J 2022;104-B(4):452–463

Aims. Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion. Methods. All patients who underwent elective THA were analyzed retrospectively in this single-centre study from 2020 to 2021. A total of 2,892 patients were included. Transfusion-related parameters were evaluated. A multiple logistic regression was performed to determine whether age, BMI, American Society of Anesthesiologists (ASA) grade, sex, or preoperative haemoglobin (Hb) could predict the need for transfusion within the examined patient population. Results. The overall transfusion rate was 1.2%. Compared to the group of patients without blood transfusion, the transfused group was on average older (aged 73.8 years (SD 9.7) vs 68.6 years (SD 10.1); p = 0.020) and was mostly female (p = 0.003), but showed no significant differences in terms of BMI (28.3 kg/m. 2. (SD 5.9) vs 28.7 kg/m. 2. (SD 5.2); p = 0.720) or ASA grade (2.2 (SD 0.5) vs 2.1 (SD 0.4); p = 0.378). The regression model identified a cutoff Hb level of < 7.6 mmol/l (< 12.2 g/dl), aged > 73 years, and a BMI of 35.4 kg/m² or higher as the three most reliable predictors associated with postoperative transfusion in THA. Conclusion. The possibility of transfusion is predictable based on preoperatively available parameters. The proposed thresholds for preoperative Hb level, age, and BMI can help identify patients and take preventive measures if necessary. Cite this article: Bone Jt Open 2024;5(7):560–564

Aims. Several previously identified patient-, injury-, and treatment-related factors are associated with the development of nonunion in distal femur fractures. However, the predictive value of these factors is not well defined. We aimed to assess the predictive ability of previously identified risk factors in the development of nonunion leading to secondary surgery in distal femur fractures. Methods. We conducted a retrospective cohort study of adult patients with traumatic distal femur fracture treated with lateral locking plate between 2009 and 2018. The patients who underwent secondary surgery due to fracture healing problem or plate failure were considered having nonunion. Background knowledge of risk factors of distal femur fracture nonunion based on previous literature was used to form an initial set of variables. A logistic regression model was used with previously identified patient- and injury-related variables (age, sex, BMI, diabetes, smoking, periprosthetic fracture, open fracture, trauma energy, fracture zone length, fracture comminution, medial side comminution) in the first analysis and with treatment-related variables (different surgeon-controlled factors, e.g. plate length, screw placement, and proximal fixation) in the second analysis to predict the nonunion leading to secondary surgery in distal femur fractures. Results. We were able to include 299 fractures in 291 patients. Altogether, 31/299 fractures (10%) developed nonunion. In the first analysis, pseudo-R. 2. was 0.27 and area under the receiver operating characteristic curve (AUC) was 0.81. BMI was the most important variable in the prediction. In the second analysis, pseudo-R. 2. was 0.06 and AUC was 0.67. Plate length was the most important variable in the prediction. Conclusion. The model including patient- and injury-related factors had moderate fit and predictive ability in the prediction of distal femur fracture nonunion leading to secondary surgery. BMI was the most important variable in prediction of nonunion. Surgeon-controlled factors had a minor role in prediction of nonunion. Cite this article: Bone Jt Open 2023;4(8):584–593

Aims. To assess the incidence of radiological lateral osteoarthritis (OA) at 15 years after medial unicompartmental knee arthroplasty (UKA) and assess the relationship of lateral OA with symptoms and patient characteristics. Methods. Cemented Phase 3 medial Oxford UKA implanted by two surgeons since 1998 for the recommended indications were prospectively followed. A 15-year cumulative revision rate for lateral OA of 5% for this series was previously reported. A total of 163 unrevised knees with 15-year (SD 1) anterior-posterior knee radiographs were studied. Lateral joint space width (JSW. L. ) was measured and severity of lateral OA was classified as: nil/mild, moderate, and severe. Preoperative and 15-year Oxford Knee Scores (OKS) and American Knee Society Scores were determined. The effect of age, sex, BMI, and intraoperative findings was analyzed. Statistical analysis included one-way analysis of variance and Kruskal-Wallis H test, with significance set at 5%. Results. The mean age was 80.6 years (SD 8.3), with 84 females and 79 males. The mean JSW. L. was 5.6 mm (SD 1.4), and was not significantly related to age, sex, or intraoperative findings. Those with BMI > 40 kg/m. 2. had a smaller JSW. L. than those with a ‘normal’ BMI (p = 0.039). The incidence of severe and moderate lateral OA were both 4.9%. Overall, 2/142 (1.4%) of those with nil/mild lateral OA, 1/8 (13%) with moderate, and 2/8 (25%) with severe subsequently had a revision. Those with severe (mean OKS 35.6 (SD 9.3)) and moderate OA (mean OKS 35.8 (SD 10.5)) tended to have worse outcome scores than those with nil/mild (mean OKS 39.5 (SD 9.2)) but the difference was only significant for OKS-Function (p = 0.044). Conclusion. This study showed that the rate of having severe or moderate radiological lateral OA at 15 years after medial UKA was low (both 4.9%). Although patients with severe or moderate lateral OA had a lower OKS than those with nil/mild OA, their mean scores (OKS 36) would be classified as good. Cite this article: Bone Jt Open 2023;4(3):210–218

Aims. The volume of ambulatory total hip arthroplasty (THA) procedures is increasing due to the emphasis on value-based care. The purpose of the study is to identify the causes for failed same-day discharge (SDD) and perioperative factors leading to failed SDD. Methods. This retrospective cohort study followed pre-selected patients for SDD THA from 1 August 2018 to 31 December 2020. Inclusion criteria were patients undergoing unilateral THA with appropriate social support, age 18 to 75 years, and BMI < 37 kg/m. 2. Patients with opioid dependence, coronary artery disease, and valvular heart disease were excluded. Demographics, comorbidities, and perioperative data were collected from the electronic medical records. Possible risk factors for failed SDD were identified using multivariate logistic regression. Results. In all, 278 patients were identified with a mean age of 57.1 years (SD 8.1) and a mean BMI of 27.3 kg/m. 2. (SD 4.5). A total of 96 patients failed SDD, with the most common reasons being failure to clear physical therapy (26%), dizziness (22%), and postoperative nausea and vomiting (11%). Risk factors associated with failed SDD included smokers (odds ratio (OR) 6.24; p = 0.009), a maximum postoperative pain score > 8 (OR 4.76; p = 0.004), and procedures starting after 11 am (OR 2.28; p = 0.015). A higher postoperative tolerable pain goal (numerical rating scale 4 to 10) was found to be associated with successful SDD (OR 2.7; p = 0.001). Age, BMI, surgical approach, American Society of Anesthesiologists grade, and anaesthesia type were not associated with failed SDD. Conclusion. SDD is a safe and viable option for pre-selected patients interested in rapid recovery THA. The most common causes for failure to launch were failing to clear physical thereapy and patient symptomatology. Risk factors associated with failed SSD highlight the importance of preoperative counselling regarding smoking cessation and postoperative pain to set reasonable expectations. Future interventions should aim to improve patient postoperative mobilization, pain control, and decrease symptomatology. Cite this article: Bone Jt Open 2022;3(9):684–691

Aims. The aim of this investigation was to compare risk of infection in both cemented and uncemented hemiarthroplasty (HA) as well as in total hip arthroplasty (THA) following femoral neck fracture. Methods. Data collection was performed using the German Arthroplasty Registry (EPRD). In HA and THA following femoral neck fracture, fixation method was divided into cemented and uncemented prostheses and paired according to age, sex, BMI, and the Elixhauser Comorbidity Index using Mahalanobis distance matching. Results. Overall in 13,612 cases of intracapsular femoral neck fracture, 9,110 (66.9%) HAs and 4,502 (33.1%) THAs were analyzed. Infection rate in HA was significantly reduced in cases with use of antibiotic-loaded cement compared with uncemented fixated prosthesis (p = 0.013). In patients with THA no statistical difference between cemented and uncemented prosthesis was registered, however after one year 2.4% of infections were detected in uncemented and 2.1% in cemented THA. In the subpopulation of HA after one year, 1.9% of infections were registered in cemented and 2.8% in uncemented HA. BMI (p = 0.001) and Elixhauser Comorbidity Index (p < 0.003) were identified as risk factors of periprosthetic joint infection (PJI), while in THA cemented prosthesis also demonstrated an increased risk within the first 30 days (hazard ratio (HR) = 2.73; p = 0.010). Conclusion. The rate of infection after intracapsular femoral neck fracture was statistically significantly reduced in patients treated by antibiotic-loaded cemented HA. Particularly for patients with multiple risk factors for the development of a PJI, the usage of antibiotic-loaded bone cement seems to be a reasonable procedure for prevention of infection. Cite this article: Bone Joint Res 2023;12(5):331–338

Aims. To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. Methods. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map. Results. After screening of 5,660 articles, we included 166 studies reporting prognostic factors for outcomes after rTKA, with a median sample size of 319 patients (30 to 303,867). Overall, 50% of the studies reported prospectively collected data, and 61% of the studies were performed in a single centre. In some studies, multiple associations were reported; 180 different prognostic factors were reported in these studies. The three most frequently studied prognostic factors were reason for revision (213 times), sex (125 times), and BMI (117 times). Studies focusing on functional scores and patient-reported outcome measures as prognostic factor for the outcome after surgery were limited (n = 42). The studies reported 154 different outcomes. The most commonly reported outcomes after rTKA were: re-revision (155 times), readmission (88 times), and reinfection (85 times). Only five studies included costs as outcome. Conclusion. Outcomes and prognostic factors that are routinely registered as part of clinical practice (e.g. BMI, sex, complications) or in (inter)national registries are studied frequently. Studies on prognostic factors, such as functional and sociodemographic status, and outcomes as healthcare costs, cognitive and mental function, and psychosocial impact are scarce, while they have been shown to be important for patients with osteoarthritis. Cite this article: Bone Jt Open 2023;4(5):338–356

Aims. This study investigates whether primary knee arthroplasty (KA) restores health-related quality of life (HRQoL) to levels expected in the general population. Methods. This retrospective case-control study compared HRQoL data from two sources: patients undergoing primary KA in a university-teaching hospital (2013 to 2019), and the Health Survey for England (HSE; 2010 to 2012). Patient-level data from the HSE were used to represent the general population. Propensity score matching was used to balance covariates and facilitate group comparisons. A propensity score was estimated using logistic regression based upon the covariates sex, age, and BMI. Two matched cohorts with 3,029 patients each were obtained for the adjusted analyses (median age 70.3 (interquartile range (IQR) 64 to 77); number of female patients 3,233 (53.4%); median BMI 29.7 kg/m. 2. (IQR 26.5 to 33.7)). HRQoL was measured using the three-level version of the EuroQol five-dimension questionnaire (EQ-5D-3L), and summarized using the Index and EuroQol visual analogue scale (EQ-VAS) scores. Results. Patients awaiting KA had significantly lower EQ-5D-3L Index scores than the general population (median 0.620 (IQR 0.16 to 0.69) vs median 0.796 (IQR 0.69 to 1.00); p < 0.001). By one year postoperatively, the median EQ-5D-3L Index score improved significantly in the KA cohort (mean change 0.32 (SD 0.33); p < 0.001), and demonstrated no clinically relevant differences when compared to the general population (median 0.796 (IQR 0.69 to 1.00) vs median 0.796 (IQR 0.69 to 1.00)). Compared to the general population cohort, the postoperative EQ-VAS was significantly higher in the KA cohort (p < 0.001). Subgroup comparisons demonstrated that older age groups had statistically better EQ-VAS scores than matched peers in the general population. Conclusion. Patients awaiting KA for osteoarthritis had significantly poorer HRQoL than the general population. However, within one year of surgery, primary KA restored HRQoL to levels expected for the patient’s age-, BMI-, and sex-matched peers. Cite this article: Bone Joint J 2023;105-B(4):365–372

Aims. Thresholds of acceptable early migration of the components in total knee arthroplasty (TKA) have traditionally ignored the effects of patient and implant factors that may influence migration. The aim of this study was to determine which of these factors are associated with overall longitudinal migration of well-fixed tibial components following TKA. Methods. Radiostereometric analysis (RSA) data over a two-year period were available for 419 successful primary TKAs (267 cemented and 152 uncemented in 257 female and 162 male patients). Longitudinal analysis of data using marginal models was performed to examine the associations of patient factors (age, sex, BMI, smoking status) and implant factors (cemented or uncemented, the size of the implant) with maximum total point motion (MTPM) migration. Analyses were also performed on subgroups based on sex and fixation. Results. In the overall group, only fixation was significantly associated with migration (p < 0.001). For uncemented tibial components in males, smoking was significantly associated with lower migration (p = 0.030) and BMI approached significance (p = 0.061). For females with uncemented components, smoking (p = 0.081) and age (p = 0.063) approached significance and were both associated with increased migration. The small number of self-reported smokers in this study warrants cautious interpretation and further investigation. For cemented components in females, larger sizes of tibial component were significantly associated with increased migration (p = 0.004). No factors were significant for cemented components in males. Conclusion. The migration of uncemented tibial components was more sensitive to patient factors than cemented implants. These differences were not consistent by sex, suggesting that it may be of value to evaluate female and male patients separately following TKA. Cite this article: Bone Joint J 2022;104-B(4):444–451

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up to determine influence of obesity versus non-obesity on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.

Multiple factors determine outcome of TKA. This study aimed to determine influence of obesity versus non-obesity, as measured by body mass index (BMI), on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Compared to non-obese patients, obese patients had inferior preoperative clinical scores, but achieved comparable ultimate clinical outcomes.

Despite inferior preoperative clinical scores, obese patients undergoing primary TKA for osteoarthritis can expect the same ultimate clinical outcome as non-obese patients.

Statistically significant differences for; mean age of obese 69.2 ±9 and non-obese 73±8 (p< 0.0001), with a higher preponderance of obese females, 70.2% vs. 30% male (p=0.033).

Despite statistically significant differences among all preoperative clinical outcomes including; KSS clinical (p=0.019), KSS function (p=0.02), Oxford (p=0.02), and flexion (p=0.001), there were no statistically significant differences among these outcomes at one-year postoperative. No statistical difference among surgical outcomes, hospital length of stay, pain scores or stair climbing ability at any interval.

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up. Statistical analysis to determine differences in demographics, surgical time, intraoperative complications, hospital length of stay, and clinical outcomes including; flexion, KSS and Oxford score, pain-level and stair climbing ability at six-week, six-month, and one-year postoperative. Patients with previous high tibial osteotomy, ORIF, or receiving associated WSIB benefits were excluded.

Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.

Aims. Previous research has demonstrated increased early complication rates following total hip arthroplasty (THA) in obese patients, as defined by body mass index (BMI). Subcutaneous fat depth (FD) has been shown to be an independent risk factor for wound infection in cervical and lumbar spine surgery, as well as after abdominal laparotomy. The aim of this study was to investigate whether increased peritrochanteric FD was associated with an increased risk of complications in the first year following THA. Methods. We analyzed prospectively collected data on a consecutive series of 1,220 primary THAs from June 2013 until May 2018. The vertical soft tissue depth from the most prominent part of the greater trochanter to the skin was measured intraoperatively using a sterile ruler and recorded to the nearest millimetre. BMI was calculated at the patient’s preoperative assessment. All surgical complications occuring within the initial 12 months of follow-up were identified. Results. Females had a significantly greater FD at the greater trochanter in comparison to males (median 3.0 cm (interquartile range (IQR) 2.3 to 4.0) vs 2.0 cm (IQR 1.7 to 3.0); p < 0.001) despite equivalent BMI between sexes (male median BMI 30.0 kg/m. 2. (IQR 27.0 to 33.0); female median 29.0 kg/m. 2. (IQR 25.0 to 33.0)). FD showed a weak correlation with BMI (R² 0.41 males and R² 0.43 females). Patients with the greatest FD (upper quartile) were at no greater risk of complications compared with patients with the lowest FD (lower quartile); 7/311 (2.3%) vs 9/439 (2.1%); p = 0.820 . Conversely, patients with the highest BMI (≥ 40 kg/m. 2. ) had a significantly increased risk of complications compared with patients with lower BMI (< 40 kg/m. 2. ); 5/60 (8.3% vs 18/1,160 (1.6%), odds ratio (OR) 5.77 (95% confidence interval (CI) 2.1 to 16.1; p = 0.001)). Conclusion. We found no relationship between peritrochanteric FD and the risk of surgical complications following primary THA. Cite this article: Bone Joint J 2020;102-B(9):1146–1150

Aims. There is evidence that morbidly obese patients have more intra- and postoperative complications and poorer outcomes when undergoing total hip arthroplasty (THA) with the direct anterior approach (DAA). The aim of this study was to determine the efficacy of DAA for THA, and compare the complications and outcomes of morbidly obese patients with nonobese patients. Methods. Morbidly obese patients (n = 86), with BMI ≥ 40 kg/m. 2. who underwent DAA THA at our institution between September 2010 and December 2017, were matched to 172 patients with BMI < 30 kg/m. 2. Data regarding demographics, set-up and operating time, blood loss, radiological assessment, Harris Hip Score (HHS), International Hip Outcome Tool (12-items), reoperation rate, and complications at two years postoperatively were retrospectively analyzed. Results. No significant differences in blood loss, intra- and postoperative complications, or implant position were observed between the two groups. Superficial wound infection rate was higher in the obese group (8.1%) compared to the nonobese group (1.2%) (p = 0.007) and relative risk of reoperation was 2.59 (95% confidence interval 0.68 to 9.91). One periprosthetic joint infection was reported in the obese group. Set-up time in the operating table and mean operating time were higher in morbidly obese patients. Functional outcomes and patient-related outcome measurements were superior in the obese group (mean increase of HHS was 52.19 (SD 5.95) vs 45.1 (SD 4.42); p < 0.001), and mean increase of International Hip Outcome Tool (12-items) was 56.8 (SD 8.88) versus 55.2 (SD 5.85); p = 0.041). Conclusion. Our results suggest that THA in morbidly obese patients can be safely and effectively performed via the DAA by experienced surgeons. Cite this article: Bone Jt Open 2022;3(1):4–11

Aims. There is little published on the outcomes after restarting elective orthopaedic procedures following cessation of surgery due to the COVID-19 pandemic. During the pandemic, the reported perioperative mortality in patients who acquired SARS-CoV-2 infection while undergoing elective orthopaedic surgery was 18% to 20%. The aim of this study is to report the surgical outcomes, complications, and risk of developing COVID-19 in 2,316 consecutive patients who underwent elective orthopaedic surgery in the latter part of 2020 and comparing it to the same, pre-pandemic, period in 2019. Methods. A retrospective service evaluation of patients who underwent elective surgical procedures between 16 June 2020 and 12 December 2020 was undertaken. The number and type of cases, demographic details, American society of Anesthesiologists (ASA) grade, BMI, 30-day readmission rates, mortality, and complications at one- and six-week intervals were obtained and compared with patients who underwent surgery during the same six-month period in 2019. Results. A total of 2,316 patients underwent surgery in 2020 compared to 2,552 in the same period in 2019. There were no statistical differences in sex distribution, BMI, or ASA grade. The 30-day readmission rate and six-week validated complication rates were significantly lower for the 2020 patients compared to those in 2019 (p < 0.05). No deaths were reported at 30 days in the 2020 group as opposed to three in the 2019 group (p < 0.05). In 2020 one patient developed COVID-19 symptoms five days following foot and ankle surgery. This was possibly due to a family contact immediately following discharge from hospital, and the patient subsequently made a full recovery. Conclusion. Elective surgery was safely resumed following the cessation of operating during the COVID-19 pandemic in 2020. Strict adherence to protocols resulted in 2,316 elective surgical procedures being performed with lower complications, readmissions, and mortality compared to 2019. Furthermore, only one patient developed COVID-19 with no evidence that this was a direct result of undergoing surgery. Level of evidence: III. Cite this article: Bone Jt Open 2022;3(1):42–53

Aims. Septic arthritis of the hip often leads to irreversible osteoarthritis (OA) and the requirement for total hip arthroplasty (THA). The aim of this study was to report the mid-term risk of any infection, periprosthetic joint infection (PJI), aseptic revision, and reoperation in patients with a past history of septic arthritis who underwent THA, compared with a control group of patients who underwent THA for OA. Methods. We retrospectively identified 256 THAs in 244 patients following septic arthritis of the native hip, which were undertaken between 1969 and 2016 at a single institution. Each case was matched 1:1, based on age, sex, BMI, and year of surgery, to a primary THA performed for OA. The mean age and BMI were 58 years (35 to 84) and 31 kg/m. 2. (18 to 48), respectively, and 100 (39%) were female. The mean follow-up was 11 years (2 to 39). Results. The ten-year survival free of any infection was 91% and 99% in the septic arthritis and OA groups, respectively (hazard ratio (HR) = 13; p < 0.001). The survival free of PJI at ten years was 93% and 99% in the septic arthritis and OA groups, respectively (HR = 10; p = 0.002). There was a significantly higher rate of any infection at ten years when THA was undertaken within five years of the diagnosis of septic arthritis compared with those in whom THA was undertaken > five years after this diagnosis was made (14% vs 5%, respectively; HR = 3.1; p = 0.009), but there was no significant difference in ten-year survival free of aseptic revision (HR = 1.14; p = 0.485). The mean Harris Hip Scores at two and five years postoperatively were significantly lower in the septic arthritis group compared with the OA group (p = 0.001 for both). Conclusion. There was a ten-fold increased risk of PJI in patients with a history of septic arthritis who underwent THA compared with those who underwent THA for OA with a ten-year cumulative incidence of 7%. The risk of any infection had a strong downward trend as the time interval between the diagnosis of septic arthritis and THA increased, highlighted by a 3.1-fold higher risk when THAs were performed within five years of the diagnosis being made. Cite this article: Bone Joint J 2022;104-B(2):227–234

The April 2024 Research Roundup. 360. looks at: Prevalence and characteristics of benign cartilaginous tumours of the shoulder joint; Is total-body MRI useful as a screening tool to rule out malignant progression in patients with multiple osteochondromas?; Effects of vancomycin and tobramycin on compressive and tensile strengths of antibiotic bone cement: a biomechanical study; Biomarkers for early detection of Charcot arthropathy; Strong association between growth hormone therapy and proximal tibial physeal avulsion fractures in children and adolescents; UK pregnancy in orthopaedics (UK-POP): a cross-sectional study of UK female trauma and orthopaedic surgeons and their experiences of pregnancy; Does preoperative weight loss change the risk of adverse outcomes in total knee arthroplasty by initial BMI classification?

Aims. This scoping review aims to identify patient-related factors associated with a poorer outcome following total ankle arthroplasty (TAA). Methods. A scoping review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A computer-based literature search was performed in PubMed, Embase, Cochrane trials, and Web of Science. Two reviewers independently performed title/abstract and full-text screening according to predetermined selection criteria. English-language original research studies reporting patient-related factors associated with a poorer outcome following TAA were included. Outcomes were defined as patient-reported outcome measures (PROMs), perioperative complications, and failure. Results. A total of 94 studies reporting 101,552 cases of TAA in 101,177 patients were included. The most common patient-related risk factor associated with poorer outcomes were younger age (21 studies), rheumatoid arthritis (17 studies), and diabetes (16 studies). Of the studies using multivariable regression specifically, the most frequently described risk factors were younger age (12 studies), rheumatoid arthritis (eight studies), diabetes (eight studies), and high BMI (eight studies). Conclusion. When controlling for confounding factors, the most commonly reported risk factors for poor outcome are younger age, rheumatoid arthritis, and comorbidities such as diabetes and increased BMI. These patient-related risk factors reported may be used to facilitate the refinement of patient selection criteria for TAA and inform patient expectations. Cite this article: Bone Joint J 2023;105-B(9):985–992

Aims. The aim of this study was to perform a systematic review and bias evaluation of the current literature to create an overview of risk factors for re-revision following revision total knee arthroplasty (rTKA). Methods. A systematic search of MEDLINE and Embase was completed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The studies were required to include a population of index rTKAs. Primary or secondary outcomes had to be re-revision. The association between preoperative factors and the effect on the risk for re-revision was also required to be reported by the studies. Results. The search yielded 4,847 studies, of which 15 were included. A majority of the studies were retrospective cohorts or registry studies. In total, 26 significant risk factors for re-revision were identified. Of these, the following risk factors were consistent across multiple studies: age at the time of index revision, male sex, index revision being partial revision, and index revision due to infection. Modifiable risk factors were opioid use, BMI > 40 kg/m. 2. , and anaemia. History of one-stage revision due to infection was associated with the highest risk of re-revision. Conclusion. Overall, 26 risk factors have been associated with an increased risk of re-revision following rTKA. However, various levels of methodological bias were found in the studies. Future studies should ensure valid comparisons by including patients with identical indications and using clear definitions for accurate assessments. Cite this article: Bone Jt Open 2024;5(8):644–651

Aims. To identify variables independently associated with same-day discharge (SDD) of patients following revision total knee arthroplasty (rTKA) and to develop machine learning algorithms to predict suitable candidates for outpatient rTKA. Methods. Data were obtained from the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) database from the years 2018 to 2020. Patients with elective, unilateral rTKA procedures and a total hospital length of stay between zero and four days were included. Demographic, preoperative, and intraoperative variables were analyzed. A multivariable logistic regression (MLR) model and various machine learning techniques were compared using area under the curve (AUC), calibration, and decision curve analysis. Important and significant variables were identified from the models. Results. Of the 5,600 patients included in this study, 342 (6.1%) underwent SDD. The random forest (RF) model performed the best overall, with an internally validated AUC of 0.810. The ten crucial factors favoring SDD in the RF model include operating time, anaesthesia type, age, BMI, American Society of Anesthesiologists grade, race, history of diabetes, rTKA type, sex, and smoking status. Eight of these variables were also found to be significant in the MLR model. Conclusion. The RF model displayed excellent accuracy and identified clinically important variables for determining candidates for SDD following rTKA. Machine learning techniques such as RF will allow clinicians to accurately risk-stratify their patients preoperatively, in order to optimize resources and improve patient outcomes. Cite this article: Bone Jt Open 2023;4(6):399–407

Aims. The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group). Methods. The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded. Results. There were significantly larger contact areas in Gruen zones 3, 5, and 6 in the N-HA group than in the T-HA group. At two years postoperatively, there was a significant decrease in BMD around the proximal-medial femur (zone 6) in the N-HA group and a significant increase in the T-HA group. BMD changes in both groups correlated with BMI or preoperative lumbar BMD rather than with the extent of contact with the femoral cortical bone. Conclusion. The N-HA-coated stem showed a significantly larger contact area, indicating a distal fixation pattern, compared with the traditional fully HA-coated stem. The T-HA-coated stem showed better preservation of periprosthetic BMD, two years postoperatively. Surgeons should consider these patterns of fixation and differences in BMD when selecting fully HA-coated stems for THA, to improve the long-term outcomes. Cite this article: Bone Joint J 2024;106-B(6):548–554

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

Aims. The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA. Methods. This study was a retrospective case-control study using the UK Biobank to identify individuals reporting a history of cruciate ligament surgery. Data from verbal history and procedural codes recorded through the NHS were used to identify instances of TKA. Patient clinical and genetic data were used to identify risk factors for progression from cruciate ligament surgery to TKA. Individuals without a history of cruciate ligament reconstruction were used for comparison. Results. A total of 2,576 individuals with a history of cruciate ligament surgery were identified, with 290 (11.25%) undergoing TKA. In patients with prior cruciate ligament surgery, prevalence of TKA was 0.75% at age 45 years, 9.10% at age 65 years, and 20.43% at age 80 years. Patients with prior cruciate ligament surgery were 4.6 times more likely to have undergone TKA by age 55 years than individuals without prior cruciate ligament surgery. In the cruciate ligament surgery cohort, BMI > 30 kg/m. 2. (odds ratio (OR) 4.01 (95% confidence interval (CI) 2.74 to 5.87)), a job that always involved heavy manual or physical labour (OR 2.72 (95% CI 1.57 to 4.71)), or a job that always involved walking and standing (OR 2.58 (95% CI 1.58 to 4.20)) were associated with greater TKA odds. No single-nucleotide polymorphism (SNP) was associated with risk of TKA following cruciate ligament surgery. Conclusion. Patients with a history of prior cruciate ligament surgery have substantially higher risk of TKA and undergo arthroplasty at a relatively younger age than individuals without a history of prior cruciate ligament surgery. Physically demanding work and obesity were associated with higher odds of TKA after cruciate ligament surgery, but no SNP was associated with risk of TKA. Cite this article: Bone Joint J 2024;106-B(3):249–255

Aims. The aim of this study was to determine both the incidence of, and the reoperation rate for, postoperative periprosthetic femoral fracture (POPFF) after total hip arthroplasty (THA) with either a collared cementless (CC) femoral component or a cemented polished taper-slip (PTS) femoral component. Methods. We performed a retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All POPFFs were identified using regional radiograph archiving and electronic care systems. Results. A total of 11,018 THAs were implanted: 4,952 CC femoral components and 6,066 cemented PTS femoral components. Between groups, age, sex, and BMI did not differ. Overall, 91 patients (0.8%) sustained a POPFF. For all patients with a POPFF, 16.5% (15/91) were managed conservatively, 67.0% (61/91) underwent open reduction and internal fixation (ORIF), and 16.5% (15/91) underwent revision. The CC group had a lower POPFF rate compared to the PTS group (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.345). Fewer POPFFs in the CC group required surgery (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). Fewer POPFFs required surgery in males with a CC than males with a PTS (0.3% (7/2,121) vs 1.3% (36/2,674); p < 0.001). Conclusion. Male patients with a PTS femoral component were five times more likely to have a reoperation for POPFF. Female patients had the same incidence of reoperation with either component type. Of those having a reoperation, 80.3% (61/76) had an ORIF, which could greatly mask the size of this problem in many registries. Cite this article: Bone Joint J 2024;106-B(2):144–150