Aims. The gluteus minimus (GMin) and gluteus medius (GMed) have unique structural and functional segments that may be affected to varying degrees, by end-stage osteoarthritis (OA) and normal ageing. We used data from patients with end-stage OA and matched healthy controls to 1) quantify the atrophy of the GMin and GMed in the two groups and 2) describe the distinct patterns of the fatty infiltration in the different segments of the GMin and GMed in the two groups. Methods. A total of 39 patients with end-stage OA and 12 age- and sex frequency-matched healthy controls were prospectively enrolled in the study. Fatty infiltration within the different segments of the GMin and the GMed was assessed on MRI according to the semiquantitative classification system of Goutallier and normalized cross-sectional areas were measured. Results. The GMin was smaller in the OA-group (p < 0.001) compared to the control group, but there was no group difference in the size of the GMed (p = 0.101). Higher levels of fatty infiltration were identified in the anterior segment of the GMin (p = 0.006) and the anterior (p = 0.006) and middle (p = 0.047) segments of the GMed in the OA group. All subjects in the control group had fatty infiltration of the anterior segment of the GMin, but all except one had no fatty infiltration in the entire GMed. Conclusion. End-stage OA was associated with significant atrophy of the GMin and higher levels of fatty infiltration, particularly in the anterior segments of the GMin and GMed. Minor fatty infiltration of the anterior segment of GMin appears to be a normal part of ageing. Our study has demonstrated different patterns of atrophy and fatty infiltration between patients with end-stage OA and healthy matched peers. Cite this article: Bone Jt Open 2021;2(1):40–47

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015-2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 12,156 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Purpose: Femoral and tibial shaft malunion may predispose to knee osteoarthritis but may also pose a problem for knee reconstruction; malposition of total knee prostheses being a known cause of early failure. Limb realignment may prove to be beneficial prior to proceeding with arthroplasty. The purpose of this study was to evaluate the outcome and effect of shaft osteotomy prior to total knee arthroplasty (TKA).

Method: A search of the trauma database between 1987 and 2006 was conducted. Twenty-two osteotomies were performed on 21 patients with femoral or tibial shaft malunion who had been considered for TKA. Mean age at osteotomy was 54 years and mean follow-up 86 months. Time intervals between surgical procedures and Knee Society scores were calculated. Patients were surveyed regarding pain relief and functional improvement.

Results: Femoral osteotomy improved mean Knee Society knee scores from 47 to 76 and function scores from 34 to 61. Tibial osteotomy improved knee scores from 53 to 82 and function scores from 28 to 50. Four osteotomies were complicated by nonunion and required further intervention. Osteotomy subjectively improved pain and function for a mean of 56 months. Femoral and tibial shaft osteotomy delayed TKA in 45% (10 cases) for a mean period of just over 6.5 years (89 and 73 months for femoral and tibial osteotomy respectively). Pre and post Knee society scores were: Femur: knee 56 to 88, function 41 to 72; Tibia: knee 65 to 85, function 25 to 57. One TKA was revised after 11 months due to valgus malalignment and was complicated by a wound infection. There were no other infections or wound complications. The procedure additionally relieved pain and improved function in the remaining 12 joints, not yet requiring arthroplasty.

Conclusion: Femoral and tibial shaft osteotomy may delay and possibly avoid TKA, relieve pain and improve function in patients who present with malunion and end-stage knee arthritis. The complication rate and clinical results of TKA following shaft osteotomy appear to be similar to primary TKA. This treatment strategy should be considered in younger patients with post traumatic osteoarthritis where significant femoral or tibial deformity is present.

Aims. Treatment of end-stage anteromedial osteoarthritis (AMOA) of the knee is commonly approached using one of two surgical strategies: medial unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). In this study we aim to investigate if there is any difference in outcome for patients undergoing UKA or TKA, when treated by high-volume surgeons, in high-volume centres, using two different clinical guidelines. The two strategies are ‘UKA whenever possible’ vs TKA for all patients with AMOA. Methods. A total of 501 consecutive AMOA patients (301 UKA) operated on between 2013 to 2016 in two high-volume centres were included. Centre One employed clinical guidelines for the treatment of AMOA allowing either UKA or TKA, but encouraged UKA wherever possible. Centre Two used clinical guidelines that treated all patients with a TKA, regardless of wear pattern. TKA patients were included if they had isolated AMOA on preoperative radiographs. Data were collected from both centres’ local databases. The primary outcome measure was change in Oxford Knee Score (OKS), and the proportion of patients achieving the patient-acceptable symptom state (PASS) at one-year follow-up. The data were 1:1 propensity score matched before regression models were used to investigate potential differences. Results. The matched cohort included 400 patients (mean age 67 years (SD 9.55), 213 (53%) female, mean BMI 30.2 kg/m. 2. , 337 (84%) American Society of Anesthesiologists grade ≤ 2). We found a mean adjusted difference in change score of 3.02 points (95% confidence interval (CI) 1.41 to 4.63; p < 0.001) and a significantly larger likeliness of achieving PASS (odds ratio 3.67 (95% CI 1.73 to 8.45); p = 0.001) both in favour of the UKA strategy. Conclusion. UKA and TKA are both good strategies for treating end-stage AMOA. However, when compared as a strategy, UKA achieved larger improvements in OKS, and were more likely to reach the PASS value at one-year follow-up. Cite this article: Bone Jt Open 2022;3(5):441–447

Aims. Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design. Methods. Patients with end-stage osteoarthritis were enrolled in a prospective cohort at a single centre. The cohort consisted of 11 females and 11 males with mean age of 70.6 years (SD 3.5) and BMI of 31.0 kg/m. 2. (SD 5.7). Implant fixation was evaluated using RSA as well as Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score, Oxford Hip Score, Hip disability and Osteoarthritis Outcome Score, 38-item Short Form survey, and EuroQol five-dimension health questionnaire scores at two-year follow-up. At least one acetabular screw was used in all cases. RSA markers were inserted into the innominate bone and proximal femur with imaging at six weeks (baseline) and six, 12, and 24 months. Independent-samples t-tests were used to compare to published thresholds. Results. Mean acetabular subsidence from baseline to 24 months was 0.087 mm (SD 0.152), below the critical threshold of 0.2 mm (p = 0.005). Mean femoral subsidence from baseline to 24 months was -0.002 mm (SD 0.194), below the published reference of 0.5 mm (p < 0.001). There was significant improvement in patient-reported outcome measures at 24 months with good to excellent results. Conclusion. RSA analysis demonstrates excellent fixation with a predicted low risk of revision at ten years of this novel reverse total hip system. Clinical outcomes were consistent with safe and effective hip replacement prostheses. Cite this article: Bone Jt Open 2023;4(5):385–392

Background. It is technically challenging to restore hip rotation center exactly in total hip arthroplasty (THA) for patients with end-stage osteoarthritis secondary to developmental dysplasia of the hip (DDH) due to the complicated acetabular morphology changes. In this study, we developed a new method to restore hip rotation center exactly and rapidly in THA with the assistance of three dimensional (3-D) printing technology. Methods. Seventeen patients (21 hips) with end-stage osteoarthritis secondary to DDH who underwent THA were included in this study. Simulated operations were performed on 3-D printed hip models for preoperative planning. The Harris fossa and acetabular notches were recognized and restored to locate acetabular center. The agreement on the size of acetabular cup and bone defect between simulated operations and actual operations were analyzed. Clinical and radiographic outcomes were recorded and evaluated. Results. The sizes of the acetabular cup of simulated operations on 3-D printing models showed a high rate of coincidence with the actual sizes in the operations(ICC value=0.930) There was no significant difference statistically between the sizes of bone defect in simulated operations and the actual sizes of bone defect in THA(t value=0.03 P value=0.97). The average Harris score of the patients was improved from (38.33±6.07) preoperatively to the last follow-up (88.61±3.44) postoperatively. The mean vertical and horizontal distances of hip rotation center on the pelvic radiographs were restored to (15.12 ± 1.25 mm and (32.49±2.83) mm respectively. No case presented dislocation or radiological signs of loosening until last follow-up. Conclusions. The application of 3-D printing technology facilitates orthopedists to recognize the morphology of Harris fossa and acetabular notches, locate the acetabular center and restore the hip rotation center rapidly and accurately

Introduction. The changes in sagittal spino-pelvic balance from standing to sitting in patients with end-stage osteoarthritis (OA) of the hip remain poorly characterized. Our aim was to 1) investigate the contribution of sagittal spino-pelvic movement and hip flexion when moving from a standing to sitting posture in patients with hip OA; 2) determine the proportion of OA-patients with stiff, normal or hypermobile spino-pelvic mobility and 3) identify radiographic parameters correlating with spino-pelvic mobility. Methods. This prospective diagnostic cohort study followed 116 consecutive patients with end-stage osteoarthritis awaiting THR. All patients underwent preoperative standardized radiographs (lateral view) of the lumbar spine, pelvis and proximal femur using EOS© in standing position and with femurs parallel to the floor in order to achieve a 90°-seated position. Radiographic measurements performed included lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI) and pelvic-femoral-angle (PFA). The difference in PT between standing and seated allowed for patient classification based on spino-pelvic mobility into stiff (<±10°), normal (±10–30°), or hypermobile (>±30°). Results. From the standing to the sitting position, the pelvis tilted backwards by a mean of 19.1° (SD 12.8) and the hip was flexed by a mean of 56.6° (SD 17.2). Change in pelvic tilt correlated inversely with change in hip flexion (r=−0.68; P<0.01; r. 2. =0.47). Thirty-two patients (28%) had stiff, 68 (58%) normal and 16 (14%) hypermobile spino-pelvic mobility. Multivariate regression analysis adjusted for patient age, BMI, static LL, SS, PI, PT and PFA showed a correlation for static standing SS and the change in PT (p=0.03; β=2.31; r. 2. =0.34). Conclusion. Hip flexion contributes on average 75% (25–100%) of the motion required to sit upright. Pre-operative assessment would identify patients with spino-pelvic hypermobility (associated greater change in cup orientation) or stiffness (associated increased hip range-of-movement), which would be at greater risk of dislocation

Demand for total knee arthroplasty (TKA) is increasing as it remains the gold-standard treatment for end-stage osteoarthritis (OA) of the knee. While magnetic-resonance imaging (MRI) scans of the knee are not indicated for diagnosing knee OA, they are commonly ordered prior to the referral to an orthopaedic surgeon. The purpose of this study was to determine the proportion of patients who underwent an MRI in the two years prior to their primary TKA for OA. Secondary outcomes included determining patient and physician associations with increased MRI usage. This is a population-based cohort study using billing codes in Ontario, Canada. All patients over 40 years-old who underwent a primary TKA between April 1, 2008 and March 31, 2017 were included. Statistical analyses were performed using SAS and included the Cochran-Armitage test for trend of MRI prior to surgery, and predictive multivariable regression model. Significance was set to p<0.05. There were 172,689 eligible first-time TKA recipients, of which 34,140 (19.8%) received an MRI in the two years prior to their surgery. The majority of these (70.8%) were ordered by primary care physicians, followed by orthopaedic surgeons (22.5%). Patients who received an MRI were younger and had fewer comorbidities than patients who did not (p<0.001). MRI use prior to TKA increased from 15.9% in 2008 to 20.1% in 2017 (p<0.0001). Despite MRIs rarely being indicated for the work-up of knee OA, nearly one in five patients have an MRI in the two years prior to their TKA. Reducing the use of this prior to TKA may help reduce wait-times for surgery

Aims. The aim of this study was to compare a bicruciate-retaining (BCR) total knee arthroplasty (TKA) with a posterior cruciate-retaining (CR) TKA design in terms of kinematics, measured using fluoroscopy and stability as micromotion using radiostereometric analysis (RSA). Methods. A total of 40 patients with end-stage osteoarthritis were included in this randomized controlled trial. All patients performed a step-up and lunge task in front of a monoplane fluoroscope one year postoperatively. Femorotibial contact point (CP) locations were determined at every flexion angle and compared between the groups. RSA images were taken at baseline, six weeks, three, six, 12, and 24 months postoperatively. Clinical and functional outcomes were compared postoperatively for two years. Results. The BCR-TKA demonstrated a kinematic pattern comparable to the natural knee’s screw-home mechanism in the step-up task. In the lunge task, the medial CP of the BCR-TKA was more anterior in the early flexion phase, while laterally the CP was more posterior during the entire movement cycle. The BCR-TKA group showed higher tibial migration. No differences were found for the clinical and functional outcomes. Conclusion. The BCR-TKA shows a different kinematic pattern in early flexion/late extension compared to the CR-TKA. The difference between both implants is mostly visible in the flexion phase in which the anterior cruciate ligament is effective; however, both designs fail to fully replicate the motion of a natural knee. The higher migration of the BCR-TKA was concerning and highlights the importance of longer follow-up. Cite this article: Bone Joint J 2023;105-B(1):35–46

Arthrodesis of the first metatarsophalangeal joint (MTPJ) is the most reliable surgical option, for hallux rigidus from end-stage osteoarthritis. The aim of the study was to compare the functional outcomes of memory nickel-titanium staples versus a compression plate with a cross screw construct for first MTPJ arthrodesis using the Manchester–Oxford Foot Questionnaire (MOXFQ). Patients who underwent MTPJ arthrodesis using either memory nickel-titanium staples or a compression plate with a cross screw construct were identified from the surgical lists of two orthopaedic consultants. Pre and post-operative MOXFQ questionnaire, a validated patient-reported outcome measure, was administered, and responses were analysed to derive the MOXFQ summary index. The study included 38 patients (staple group N=12 and plate and cross screw group N=26). 23 patients were female and 15 were male. Mean age was 64.8 years (SD 9.02; 40 to 82). Initial analysis showed no significant difference in preoperative MOXFQ scores between the groups (p = 0.04). Postoperatively, the staple group exhibited a mean improvement of 36.17, surpassing the plate group's mean improvement of 23. Paired t-test analysis revealed a statistically significant difference (t-score= 2.5, p = 0.008), favouring the use of staples. The findings indicate that the use of staples in MTPJ arthrodesis resulted in a significantly greater improvement in MOXFQ scores compared to plates. Further research is needed to explore the underlying factors contributing to this difference and to evaluate long-term effects on patient outcomes

Abstract. Introduction. Articular cartilage degradation is a defining feature of osteoarthritis. Synovium is a reactive tissue with synovial villae, neoangiogenesis and intimal hyperplasia common to many joint pathologies. The consequences of cartilage debris in osteoarthritis impacting the synovial intima is not well understood. We analysed the immunohistology of synovium from 16 patients with osteoarthritis and 17 patients undergoing knee surgery for non-arthritic pathologies. This data was integrated with imaging and functional scores to correlate synovitis in osteoarthritis. Methodology. Formalin-fixed paraffin embedded synovial biopsy sections were cut in serial sequence and processed for routine staining (H&E or CD3, CD68, CD20, Vimentin, vWF and PCNA IHC) using standardised Dako monoclonal mouse anti-human antibodies. Digital images scanned at x20 were evaluated for fragments of cartilage and aggregates of inflammatory cells. Clinical data (gender, BMI, KL grade, WOMAC & SF-12 scores) was aligned with histopathological data. Results. Cartilage fragments were seen in the synovial intimal layer from end-stage osteoarthritis especially those with BMI<30kg/m2. Macrophages, T-cells and B-cells were identified surrounding cartilage inclusions. Inflammatory aggregates of T-cells, B-cells and macrophages were located peri-cartilage in the intima and peri-vascular in the sub-intimal layer of the synovium. Worse synovitis and function scores were significantly associated with both cartilage inclusions and inflammatory aggregates. X-ray features linked to longer duration of symptoms were associated with inflammatory aggregates. Conclusion. The histological features of the synovium clearly reflect deteriorating joint structures and compromised clinical function

Objectives. The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue. Methods. A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity. Results. There was a significant difference in the storage modulus between torn (mean modulus = 2144.08 Pa) and non-torn (3178.1 Pa) labra (p = 0.0001). Conclusion. The acetabular labrum of young patients with a tear has significantly reduced structural integrity compared with a non-torn labrum in older patients with end-stage osteoarthritis. This study contributes to the understanding of the biomechanics of labral tears, and the observation of reduced structural integrity in torn labra may explain why some repairs fail. Our data demonstrate that labral tears probably have a relatively narrow phenotype, presenting a basis for further investigations that will provide quantifiable data to support their classification and a means to develop a standardized surgical technique for their repair. This study also demonstrates the value of novel biomechanical testing methods in investigating pathological tissues of orthopaedic interest. Cite this article: A. K. Woods, J. Broomfield, P. Monk, F. Vollrath, S. Glyn-Jones. Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair. Bone Joint Res 2018;7:440–446. DOI: 10.1302/2046-3758.77.BJR-2017-0282.R2

Total hip replacement (THR) for end-stage osteoarthritis is a commonly performed cost-effective procedure, which provides patients with significant clinical improvement. Estimating the future demand for joint replacement is important to identify the healthcare resources needed. We estimated the number of primary THRs that will need to be performed up to the year 2060. We used data from The National Joint Registry for England, Wales, Northern Ireland and the Isle of Man on the current volume of primary THR (n=94,936) performed in 2018. We projected future numbers of THR using a static estimated rate from 2018 applied to population growth forecast data from the UK Office for National Statistics up to 2060. By 2060, primary THR volume would increase from 2018 levels by an estimated 37.7% (n=130,766). For both males and females demand for surgery was also higher for patients aged 70 and over, with older patients having the biggest relative increase in volume over time: 70–79 years (144.6% males, 141.2% females); 80–89 years (212.4% males, 185.6% females); 90 years and older (448.0% males, 298.2% females). By 2060 demand for THR is estimated to increase by almost 40%. Demand will be greatest in older patients (70 years+), which will have significant implications for the health service that requires forward planning given morbidity and resource use is higher in this population. There is a backlog of current demand with cancellation of elective surgery due to seasonal flu pressures in 2017 and now Covid-19 in 2020. Orthopaedics already has the largest waiting list of any speciality. These issues will negatively impact the health services ability to deliver timely joint replacement to many patients for a number of years and require urgent planning

Introduction. The degree of cartilage degeneration assessed intraoperatively may not be sufficient as a criterion for patellar resurfacing in total knee arthroplasty (TKA). However, single-photon emission tomography/computed tomography (SPECT/CT) is useful for detecting osteoarthritic involvement deeper in the subchondral bone. The purpose of the study was to determine whether SPECT/CT reflected the cartilage lesion underneath the patella in patients with end-stage osteoarthritis (OA) and whether clinical outcomes after TKA without patellar resurfacing differed according to the severity of patellofemoral (PF) OA determined by visual assessment and SPECT/CT findings. Methods. This study included 206 knees which underwent TKA. The degree of cartilage degeneration was graded intraoperatively according to the International Cartilage Repair Society grading system. Subjects were classified into four groups according to the degree of bone tracer uptake (BTU) on SPECT/CT in the PF joint. The Feller's patella score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were assessed preoperatively and postoperative 1 and 2 years. Results. The increased BTU in the PF joint was associated with more severe degenerative cartilage changes underneath the patella (P < 0.001). The risk for the presence of denudated cartilage was greater in the high uptake group (odds ratio = 5.89). There was no association between clinical outcomes and visual grading of patellar cartilage degeneration or the degree of BTU on SPECT/CT. Discussion and Conclusions. The visual assessment of the degree of cartilage degeneration underneath the patella and preoperative SPECT/CT evaluation of the PF joint were not predictive of clinical outcome after TKA with unresurfaced patella

Introduction. Patients undergoing total knee arthroplasty (TKA) with end-stage osteoarthritis of knee have secondary foot and ankle pathology. Some compensatory changes occur at ankle and subtalar joint secondary to malalignment and deformity at the knee joint. Purpose was to evaluate the changes in hindfoot malalignment and foot deformities in patients with advanced osteoarthritis of knee requiring TKA and effect of correction of knee deformities post TKA on foot/Ankle alignment. Methods. 61 consecutive patients with Kellgren-Lawrence grade IV osteoarthritis knee undergoing TKA were enrolled in a prospective blinded study. Demographic data, deformities at knee and ankle, hindfoot malalignment and functional outcome scores such as VAS, KSS, WOMAC scores, Foot and Ankle Disability Index (FADI) and Foot posture index (FPI) were recorded preoperatively and postoperatively at 6, 12 weeks and final follow up (range: 6–21 months; mean: 14.2months). Results. Statistically significant improvement was observed in KSS score, WOMAC score, FADI and FPI after TKA. There was improvement in ankle valgus after correction of knee varus deformity. Hind foot changes mainly occured at subtalar joint. Hallux valgus (10 patients), and Pesplanus (5 patients) were associated with advanced osteoarthritis of knee. Gait profile score and Gait deviation index improved significantly after TKA. There was increased stance phase and decreased stride length in knee osteoarthritis patients which improved after TKA. Conclusion. Hind foot malalignment with foot deformities (hind foot valgus) occur secondary to knee malalignment and deformities (varus deformity) in advanced osteoarthritis of knee which subsequently improve following TKA

Background. Total hip arthroplasty (THA) has been and continues to be the gold standard for treatment of end-stage osteoarthritis. With each year, implant characteristics are evolving to increase patient-reported outcomes and decrease complications. Purpose: to report minimum 2-year outcomes and complications in patients who underwent robotic-arm assisted THA using Corin versus Stryker-type implants. Methods. Data were prospectively collected on patients who underwent THA with Corin-type implants (both cup and stem) and THA using Stryker implants between June 2011 and July 2016. A 1:1 propensity match was performed using the following 5 covariates: age, body mass index, gender, Charlson score and smoking status. Surgical outcomes were assessed at minimum 2-year follow-up using the Forgotten Joint Score (FJS), Harris Hip Score (HHS), Veterans RAND 12-item physical and mental health survey, Short Form 12 physical and mental health survey, Visual Analog Score (VAS), and patient satisfaction. The exclusion criteria were previous hip condition/surgery, workers compensation, or were unwilling. Results. Of the eligible 774 cases, 645 patients (83.3%) had minimum 2-year follow-up and met inclusion and exclusion criteria. Of the 645 patients, 323 had Corin implants, and 155 had Stryker implants. The 1:1 propensity match successfully yielded 290 patients (145 per implant group) which had a minimum 2-year follow-up at a mean 38.3 months (range, 24.1–65.3 months). Average age was 59.9 (range, 34.92–79.89 Stryker group, 30.65–75.92 Corin group) for each group and average BMI were 30.0 (range, 19.05–49.33) kg/m. 2. for the Stryker group and 29.77 (range, 20.15–55.37) kg/m. 2. for the Corin group. FJS (P=0.0388) and patient satisfaction (P=0.0019) were significantly higher in the Stryker implant group than the Corin implant group. There were nine cases of postoperative thigh numbness or paresthesias, three cases of wound infection, and one case of nonunion in the Corin-implant group. There were four cases of postoperative thigh numbness or parasthesias and six cases of wound infection in the Stryker-implant group. Conclusion. At minimum 2-year follow-up, patients who had undergone THA with Stryker-type implants had significantly higher FJS and satisfaction and a trend toward decreased complications than patients with Corin-type implants. These results can help guide decision making for surgical instrumentation by arthroplasty surgeons

Total hip replacements (THRs) provide pain relief and improved function to thousands of patients suffering from end-stage osteoarthritis, every year. Over 800 different THR constructs were implanted in the UK in 2017. To ensure reliable implants are used, a NICE revision benchmark of 5% after 10 years exists. Given the 10-year cumulative mortality of patients under 55 years of age receiving THRs is only 5% and that a recent study suggests 25-year THR survival of 58%, we aim to produce revision estimates out to 30 years that may guide future long-term benchmarks. The local database of the Princess Elizabeth Orthopaedic Centre (PEOC), Exeter, holds data on over 20,000 patients with nearly 30-years follow-up with contemporary prostheses. A previous study suggests that the results of this centre are generalisable if comparisons restricted to the same prostheses. Via flexible parametric survival analysis, we created an algorithm using this database, for revision of any part of the construct for any reason, controlling for age and gender. This algorithm was applied to 664,761 patients in the NJR who have undergone THR, producing a revision prediction for patients with the same prostheses as those used at this centre. Using our algorithm, the 10-year predicted revision rate of THRs in the NJR was 2.2% (95% CI 1.8, 2.7) based on a 68-year-old female patient; well below the current NICE benchmark. Our predictions were validated by comparison to the maximum observed survival in the NJR (14.2 years) using restricted mean survival time (P=0.32). Our predicted cumulative revision estimate after 30 years is 6.5% (95% CI 4.5, 9.4). The low observed and predicted revision rate with the prosthesis combinations studied, suggest current benchmarks may be lowered and new ones introduced at 15 and 20 years to encourage the use of prostheses with high survival

Introduction and Objective. Total joint replacement (TJR) is indicated for patients with end-stage osteoarthritis (OA) where conservative treatment has failed. Approximately 1.3 million primary hip replacement surgeries have been recorded in the United Kingdom since 2003 and this number is set to rise due to an increase in obesity as well as an ageing population. Total hip replacement (THR) has a survival rate of 85% at 20 years; the most common reason for failure is aseptic loosening which often occurs secondary to osteolysis caused by immune-mediated inflammation responses to wear debris generated from the materials used in the THR implant. Therefore, by understanding the biological steps by which biomaterials cause immune-mediated reactions it should be possible to prevent them in the future thereby reducing the number of costly revision surgeries required. Materials and Methods. The human osteoblast-like cell line (MG-63) was seeded at a density of 100,000 cell per well of a 6-well plate and treated with and increasing doses (0.5, 5, and 50mm. 3. per cell) of cobalt-chromium (CoCr) particles generated on a six-station pin-on-plate wear generator or commercially available ceramic oxide nanopowders (Al. 2. O. 3. and ZrO. 2. ) for 24 hours. TNF-alpha was used as a positive control and untreated cells as a negative control. Cells were then analysed by transmission electron microscopy (TEM) to determine whether the osteoblasts were capable of phagocytosing these biomaterials. MG-63 cells were used in conjunction with trypan blue and the XTT Cell Proliferation II Kit to assess cytotoxicity of the biomaterials investigated. Cells supernatants were also collected and analysed by enzyme-linked immunosorbant assay (ELISA) to investigate changes in pro-inflammatory protein secretion. Protein extracted from lysed cells was used for western blotting analysis to investigate RANKL protein expression to determine changes to osteolytic activation. Lysed cells were also used for RNA extraction and subsequent cDNA synthesis for real-time quantitative polymerase chain reaction (RT-qPCR) in order to assess changes to pro-inflammatory gene expression. Results. There was no significant change to cellular viability or proliferation in the osteoblasts treated with CoCr, Al. 2. O. 3. or ZrO. 2. when compared to the untreated negative control. TEM images showed clear and distinct intracellular vesicles within the cell cytoplasm which contained CoCr, Al. 2. O. 3. and ZrO. 2. RANKL expression increased at 5 and 50mm. 3. per cell CoCr and 50mm. 3. per cell Al. 2. O. 3. and ZrO. 2. Pro-inflammatory protein secretion of CXCL10, IL-8, and IL-6 all significantly increased at 50mm. 3. per cell CoCr, Al. 2. O. 3. , and ZrO. 2. Similarly to the protein secretion, CXCL10, IL-8, and IL-6 gene expression was significantly upregulated at 50mm. 3. per cell CoCr, Al. 2. O. 3. , and ZrO. 2. Conclusions. Increased in vitro RANKL expression in response to CoCr, Al. 2. O. 3. , and ZrO. 2. may result in disruption of bone metabolism and lead to osteolysis which can contribute to aseptic loosening in vivo. Significant increases in IL-6 are particularly important because as well as being a pro-inflammatory cytokine, IL-6 is also secreted by osteoblasts in order to stimulate mature osteoclast formation to mediate bone breakdown. CXCL10 and IL-8 are chemotactic cytokines and increased secretion in response to implant biomaterials can contribute to ongoing pro-inflammatory responses through the recruitment of monocytes and neutrophils respectively. This is interesting as in vivo data demonstrates increased cellular infiltrate in patients experiencing responses to implant materials. Overall, these findings show clear immune activation as well as altered metabolism of MG-63 osteoblast cells in response to implant wear debris which is in agreement with in vivo clinical reports

Spinopelvic mobility describes the change in lumbar lordosis and pelvic tilt from standing to sitting position. For 1° of posterior pelvic tilt, functional cup anteversion increases by 0.75° after total hip arthroplasty (THA). Thus, spinopelvic mobility is of high clinical relevance regarding the risk of implant impingement and dislocation. Our study aimed to 1) determine the proportion of OA-patients with stiff, normal or hypermobile spino-pelvic mobility and 2) to identify clinical or static standing radiographic parameters predicting spinopelvic mobility. This prospective diagnostic cohort study followed 122 consecutive patients with end-stage osteoarthritis awaiting THA. Preoperatively, the Oxford Hip Score, Oswestry Disability Index and Schober's test were assessed in a standardized clinical examination. Lateral view radiographs were taken of the lumbar spine, pelvis and proximal femur using EOS© in standing position and with femurs parallel to the floor in order to achieve a 90°-seated position. Radiographic measurements were performed for the lumbar lordosis angle (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI) and pelvic-femoral-angle (PFA). The difference in PT between standing and seated allowed for patient classification based on spino-pelvic mobility into stiff (±30°). From the standing to the sitting position, the pelvis tilted backwards by a mean of 19.6° (SD 11.6) and the hip was flexed by a mean of 57° (SD 17). Change in pelvic tilt correlated inversely with change in hip flexion. Spinopelvic mobility is highly variable in patients awaiting THA and we could not identify any clinical or static standing radiographic parameter predicting the change in pelvic tilt from standing to sitting position. In order to identify patients with stiff or hypermobile spinopelvic mobility, we recommend performing lateral view radiographs of the lumbar spine, pelvis and proximal femur in all patients awaiting THA. Thereafter, implants and combined cup inclination/anteversion can be individually chosen to minimize the risk of dislocation. No predictors could be identified. We recommend performing sitting and standing lateral view radiographs of the lumbar spine and pelvis to determine spinopelvic mobility in patients awaiting THA

While total joint replacement (TJR) is considered as an effective intervention to relieve pain and restore joint function for end-stage osteoarthritis (OA) patients, a significant proportion of the patients are dissatisfied with their surgery outcomes. The aim of this study was to identify genetic factors that can predict patients who do or do not benefit from these surgical procedures by a genome-wide association study (GWAS). Study participants were derived from the Newfoundland Osteoarthritis Study (NFOAS) which consisted of 1086 TJR patients. Non-responders to TJR was defined as patients who did not reach the minimum clinically important difference (MCID) based on the self administered Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in terms of pain reduction or function improvment. DNA was extracted from the blood samples of the study participants and genotyped by Illumina GWAS genotyping platform. Over two million single nucleotide polymorphisms (SNPs) across the genome were genotyped and tested for assocition with non-responders. 39 non-responders and 44 age, sex, and BMI matched responders were included in this study. Four chromosome regions on chromosomes 5, 7, 8, and 12 were suggested to be associated with non-responders with p < 1 0–5. The most promising one was on chromosome 5 with the lead SNP rs17118094 (p=1.7×10–6) which can classify 72% of non-responders accurately. The discriminatory power of this SNP alone is very promising as indicated by an area under the curve (AUC) of 0.72 with 95% confidence interval of 0.63 to 0.81, which is much better than any previously studied predictors mentioned above. All the patients who carry two copies of the G allele (minor allele) of rs17118094 were non-responders and 75% of those who carry one copy of the G allele were non-responders. The discriminatory ability of the lead SNPs on chromosomes 7 and 12 were comparable to the one on chromosome 5 with an AUC of 0.74, and 88% of patients who carry two copies of the A allele of rs10244798 on chromosome 7 were non-responders. Similarly, 88% of patients who carry two copies of the C allele of rs10773476 on chromosome 12 were non-responders. While the discriminatory ability of rs9643244 on chromosome 8 was poor with an AUC of 0.26, its strong association with non-responders warrants a further investigation in the region. The study identified four genomic regions harboring genetic factors for non-responders to TJR. The lead SNPs in those regions have great discriminatory ability to predict non-responders and could be used to create a genetic prediction model for clinical unitilty and application