Abstract. Introduction. Component mal-positioning in total hip replacement (THR) and total knee replacement (TKR) can increase the risk of revision for various reasons. Compared to conventional surgery, relatively improved accuracy of implant positioning can be achieved using computer assisted technologies including navigation, patient-specific jigs, and robotic systems. However, it is not known whether application of these technologies has improved prosthesis survival in the real-world. This study aimed to compare risk of revision for all-causes following primary THR and TKR, and revision for dislocation following primary THR performed using computer assisted technologies compared to conventional technique. Methods. We performed an observational study using National Joint Registry data. All adult patients undergoing primary THR and TKR for osteoarthritis between 01/04/2003 to 31/12/2020 were eligible. Patients who received metal-on-metal bearing THR were excluded. We generated propensity score weights, using Sturmer weight trimming, based on: age, gender, ASA grade, side, operation funding, year of surgery, approach, and fixation. Specific additional variables included position and bearing for THR and patellar resurfacing for TKR. For THR, effective sample sizes and duration of follow up for conventional versus computer-guided and robotic-assisted analyses were 9,379 and 10,600 procedures, and approximately 18 and 4 years, respectively. For TKR, effective sample sizes and durations of follow up for conventional versus computer-guided, patient-specific jigs, and robotic-assisted groups were 92,579 procedures over 18 years, 11,665 procedures over 8 years, and 644 procedures over 3 years, respectively. Outcomes were assessed using Kaplan-Meier analysis and expressed using hazard ratios (HR) and 95% confidence intervals (CI). Results. For THR, analysis comparing computer-guided versus conventional technique demonstrated HR of 0.771 (95%CI 0.573–1.036) p=0.085, and 0.594 (95%CI 0.297–1.190) p=0.142, for revision for all-causes and dislocation, respectively. When comparing robotic-assisted versus conventional technique, HR for revision for all-causes was 0.480 (95%CI 0.067 –3.452) p=0.466. For TKR, compared to conventional surgery, HR for all-cause revision for procedures performed using computer guidance and patient-specific jigs were 0.967 (95% CI 0.888–1.052) p=0.430, and 0.937 (95% CI 0.708–1.241) p=0.65, respectively. HR for analysis comparing robotic-assisted versus conventional technique was 2.0940 (0.2423, 18.0995) p = 0.50. Conclusions. This is the largest study investigating this topic utilising propensity score analysis methods. We did not find a statistically significant difference in revision for all-causes and dislocation although these analyses are underpowered to detect smaller differences in effect size between groups. Additional comparison for revision for dislocation between robotic-assisted versus conventionally performed THR was not performed as this is a subset of revision for all-causes and wide confidence intervals were already observed for that analysis. It is also important to mention this NJR analysis study is of an observational study design which has inherent limitations. Nonetheless, this is the most feasible study design to answer this research question requiring use of a large data set due to revision being a rare outcome. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Primary bony tumours of the elbow account for approximately 1% of all osseous tumours. The delayed diagnosis is commonly reported in the literature as a result of lack of clinician familiarity. We present the largest series of primary bone tumours of the elbow in the English literature.

We sought to identify characteristics specific to primary elbow tumours and compare these to the current literature. We discuss cases of misdiagnosis and reasons for any delay in diagnosis. The authors also recommend a collaborative protocol for the diagnosis and management of these rare tumours.

A prospectively collected national database of all bone tumours is maintained by an independent clerk. The registry and case notes were retrospectively reviewed from January 1954 until June 2013. Eighty cases of primary osseous elbow tumours were studied. Tumours were classified as benign or malignant and then graded according to the Enneking spectrum.

There were no benign latent cases in this series. All cases in this series required surgical intervention. These cases presented with persistent rest pain, with or without swelling. The distal humerus was responsible for the majority and most aggressive of cases. The multidisciplinary approach at a specialist centre is integral to management. Misdiagnosis was evident in 12.5 % of all cases. Malignant tumours carried a 5-year mortality of 61%. Benign tumours exhibited a 19% recurrence rate and in particular, giant cell tumour was very aggressive. The evolution in treatment modalities has clearly benefited patients.

Clinicians should be aware that elbow tumours can be initially misdiagnosed as soft tissue injuries or cysts. The suspicion of a tumour should be raised in the patient with unremitting, unexplained non-mechanical bony elbow pain. We suggest an investigatory and treatment protocol to avoid a delay to diagnosis. With high rates of local recurrence, we recommend regular postoperative reviews.

Abstract. Purpose. Clinical registries are an important aspect of orthopaedic research in assessing the outcomes of surgical intervention and track medical devices. This study aimed to explore the research methodology available to account for patients lost to follow-up (LTFU) specifically in studies related to arthroscopic intervention and whether the rates of patient LTFU are within the acceptable margins for survey studies. Methods. A scoping review, where a literature search for studies from nine arthroscopy registries, was performed on EMBASE, MEDLINE, and the annual reports of each registry. Inclusion criteria included studies with information on patient-reported outcome measures and being based on nine national registries identified. Exclusion criteria included review articles, conference abstracts, studies not based on registry data, and studies from regional, claims-based, or multi-centre registries. Studies were then divided into categories based on method of LTFU analysis used. Results. Thirty-six articles were identified for the final analysis. Categories for LTFU analysis included dropout analyses (n=10), referencing validation studies (n=12), contacting non-responders (n=4), and sensitivity analyses (n=1). Referencing validation studies was the most common method (n=12). Majority (n=35) of the studies exceeded the recommended maximum rates for LTFU. Conclusions. Most arthroscopy studies have rates of LTFU higher than traditionally acceptable. Therefore, any conclusions drawn from these research papers may not be sufficiently valid or free from non-response bias

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

Patients with Paget's Disease of Bone (PDB) more frequently require total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, controversy remains regarding their outcome. This project aims to evaluate the current literature regarding outcomes following THA and TKA in PDB patients. MEDLINE, EMBASE and Cochrane databases were searched on February 15th, 2022. Inclusion criteria comprised studies evaluating outcomes following THA/TKA in PDB patients. Quality of included studies was assessed using the Newcastle-Ottawa Scale. 19 articles (published between 1976–2022) were included, comprising 58,695 patients (48,766 controls and 10,018 PDB patients), from 209 potentially relevant titles. No study was of high quality. PDB patient pooled mortality was 32.5% at mean 7.8(0.1-20) years following THA and 31.0% at mean 8.5(2-20) years following TKA. PDB patient revision rate was 4.4% at mean 7.2(0-20) years following THA and 2.2% at mean 7.4(2-20) years following TKA. Renal complications, respiratory complications, heterotopic ossification, and surgical site infection were the most common medical and surgical complications. The largest systematic review, to date, evaluating outcomes following THA and TKA in PDB patients. All functional outcome scores improved. PDB patient revision rate was comparable to UK National Joint Registry. However, there is a significant need for prospective matched case-control studies to robustly compare outcomes in PDB patients with unaffected counterparts

Background. In the UK, over 160,000 total joint replacements are performed annually. About 1% of patients subsequently develop a deep bacterial infection and, if untreated, this can result in severe pain, disability, and death. Costs to the NHS are substantial. The INFORM (Infection Orthopaedic Management) programme aims to address gaps in knowledge relating to treatment of deep prosthetic joint infection through six work packages. The programme is supported by a patient forum and patient-partners working on oversight groups. Methods. Literature reviews and meta-analysis of individual patient data from cohort studies of patients treated for prosthetic hip infection. Analysis of the National Joint Registry to observe trends in infection rates, and identify risk markers for infection and effective treatments. Qualitative interviews with patients and health professionals exploring the impact of infection and its treatment. A multicentre randomised controlled trial to compare patient-centred outcomes after one- or two-stage revision for prosthetic hip infection. An economic evaluation to assess cost-effectiveness of treatments. A survey of patients to explore individuals’ preferences for treatments. Results. Individual patient data has been provided by UK and international centres. Data on over 1.4 million procedures is available from the National Joint Registry. Interviews conducted with 19 patients with prosthetic hip infection and 12 treating surgeons. Information has advised randomised controlled trial methodology. Seven major UK centres recruiting patients to the INFORM randomised controlled trial. Methods for assessment of costs from a health service and societal perspective developed for the randomised controlled trial. Qualitative studies have contributed to the design of a discrete choice questionnaire. Conclusions. Findings from INFORM will establish how patient care and outcomes can be optimised after prosthetic joint infection. Guidance on best clinical practice will be developed. Level of evidence 1–3. Funding statement This abstract presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this abstract are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

Pre-operative anaemia can present in up to 30% of elective arthroplasty patients. The presence of anaemia increases the risk of requiring blood transfusion post-operatively as well as acts as an independent risk factor for poor outcome such as prosthetic joint infection. Recent international consensus on this topic has recommended a specific care pathway for screening patients with pre-operative anaemia using a simple bedside Heaemacue finger-prick test to detect in a simple and cost-effective manner, and then allow treatment of preoperative anaemia. This pathway was therefore incorporated in our trust. This was a retrospective study done at a single tertiary-referral arthroplasty centre. Our data collection included the Heamacue test results and formal haemoglobin levels if they were performed as well as compliance and costs of each of the tests for patients listed for an elective shoulder, hip and knee arthroplasty between September and December 2018. Medical records and demographics were also collected for these patients for subgroup analysis. Our exclusion criteria comprised patients listed for revision arthroplasty surgery. 87 patients were included in this study. Our compliance rate was 15%. The mean difference between a Haemacue test and a formal FBC result was only 17.6g/L suggesting that it has a reasonably high accuracy. With regards to costs, we found that a Haemacue test costs £2, compared to £7.50 for a full blood count and Haematinics combined. This gave an overall cost saving of £5.50 per patient. Extrapolation of this date locally for 2017 at our hospital, where 1575 primary joint arthroplasties were done, a cost saving of £8,662.5 could have been achieved. Within the UK using data extrapolated from the National Joint Registry a total of £1,102,205.5 (1,221,894 Euros) could have been saved. The use of a single, Haemacue test to screen for pre-operative anaemia in elective arthroplasty patients is more cost effective compared to a formal full count and haematinics tests. However, we found that compliance with the care pathway is variable due to system limitations. This may be addressed through implementing changes to our electronic system in which patients are booked for surgery. We also noted a significant cost reduction if this pathway were to be used Nation-wide. Thus, we encourage other centres to consider the use of the Haemacue test pre-operatively in elective arthroplasty instead of formal full blood counts at the time of decision to treat with arthroplasty; this allows sufficient time for correction of pre-operative anaemia thus improving patient outcomes from arthroplasty

The aim of this study was to report the procedure survival and patient-reported outcomes in a consecutive series of patients <50yrs at the time of hip arthroplasty with a metal-on-metal hip resurfacing system who have progressed to a minimum of 10yrs follow-up. Patients presenting for treatment of degenerative conditions of the hip electing to undergo hip resurfacing were included in a clinical registry (N=226 patients; 238 procedures). Procedure survival was confirmed by crosschecking to the Australian Orthopaedic Association National Joint Replacement Registry and comparing to all procedures by other surgeons nationwide. Kaplan-meier survival curves with 95% confidence intervals were constructed, while patient-reported outcome measures were compared with t-tests and postoperative scores assessed with anchor analysis to age and gender-matched normative data. At mean follow up of 12 years, six cases were revised with a cumulative survival rate of 96.8% (95%CI 94.2–99.4) at 15 years. Majority of revisions were early (<3yrs) and occurred in females (N=4). Patient-reported general health, disease state, hip function and activity level maintained large improvements beyond 10 years post-implantation and were equal to or exceeded age and gender-matched normative data. Metal-on-metal hip resurfacing in males and females aged <50 years at time of surgery demonstrated a high rate of cumulative survival beyond 10 years follow up. The results demonstrate excellent outcomes in this age group

Total knee arthroplasty (TKA) is a common orthopaedic procedure with over 1,500 done in 2016 in Ireland alone. 96% of all TKAs are due to pain in the knee associated with osteoarthritis. According to the UK National Joint Registry (NJR), there is a 0.47%, 1.81%, 2.63% and 4.34% probability risk of undergoing a revision TKA within one, three, five and ten years respectively post-index surgery. A variety of reasons for failure of TKA have been described in the literature including infection, aseptic loosening, pain, instability, implant wear, mal-alignment, osteolysis, dislocation, peri-prosthetic fracture and implant fracture. The NexGen Posterior Stabilised Fixed has NJR revision rates of 0.44%, 1.61% and 2.54% at years one, three and five respectively. A retrospective review was carried out of 350 NexGen TKAs that were performed directly by, or under the supervision of, a fellowship trained arthroplasty surgeon in a dedicated orthopaedic hospital between April 2013 and December 2015. 26 (7.4%) of these were revised as of 31 December 2017. Three were for septic arthritis with the remaining 23 (6.6%) for aseptic loosening. Patients typically started to experience symptoms of medial tibial pain with supra-patellar swelling from a combination of effusion and synovial thickening at 12–24 months. Inflammatory markers were normal in all cases. Radiographs of symptomatic knee replacements showed bone loss on the medial tibia with a tilt of the tibial component into a varus alignment. The high number of revisions of this particular prosthetic has led to its use being discontinued at this centre

Periprosthetic joint infections (PJIs) are uncommon but are devastating complications of total knee replacement (TKR). We analysed the risk factors of revision for PJI following primary TKR and their association with PJI at different post-operative periods. Primary TKRs and subsequent revision surgeries performed for PJI from 2003–2014 were identified from the National Joint Registry (NJR). Multilevel piece-wise exponential non-proportional hazards models were used to estimate the effect of the investigated factors at different post-operative periods. Patient, perioperative and healthcare system characteristics were investigated and data from the Hospital Episode Statistics for England were linked to obtain information on specific comorbidities. The index TKRs consisted of 679,010 primaries with 3,659 subsequently revised for PJI, 7% within 3 months, 6% between 3–6months, 17% between 6–12months, 27% between 1–2years and 43% ≥2 years from the index procedure. Risk factors for revision for PJI included male sex, high BMI, high ASA grade and young age. Patients with chronic pulmonary disease, diabetes and liver disease had higher risk of revision for PJI, as had patients who had a primary TKR for an indication of trauma or inflammatory arthropathy. Surgical procedure, fixation method, constraint and bearing type influenced the risk of revision for PJI. Their effects were period-specific. No or small associations were found with the operating surgeon grade, surgical volume and hospital surgical volume. These findings from the world's largest joint replacement registry show a more complex picture than the meta-analyses published to date with specific time-dependent effects for the identified risk factors

Introduction. Prosthetic joint infection (PJI) is an uncommon but serious complication of hip replacement. A recent systematic review of patient risk factors for PJI identified male gender, smoking status, increasing BMI, steroid use, previous joint surgery and comorbidities of diabetes, rheumatoid arthritis and depression as risk factors for developing PJI. Limitations of the current literature include the short term follow up of most published studies. We investigated the role of patient, surgical and healthcare factors on the risk of revision of a primary hip replacement for PJI at different time-points in the post-operative follow-up. It is important that those risk factors are identified so that patients can be appropriately counselled according to their individual risk profile prior to surgery and modifiable factors can be addressed to reduce the risk of PJI at an individual and healthcare system level. Materials and Methods. Primary hip replacements and subsequent revision procedures performed for PJI from 2003–2014 were identified from the National Joint Registry (NJR). Patient (age, gender, ASA grade, BMI), perioperative (surgical indication, type of anaesthesia, thromboprophylaxis regime, surgical approach, hip replacement and bearing surface and use of femoral or acetabular bone graft) and healthcare system characteristics (surgeon grade, surgical volume) were linked with data from Hospital Episode Statistics to obtain information on specific ethnicity and comorbidities (derived from the Charlson index). Multilevel piecewise exponential non-proportional hazards models were used to estimate their effects at different post-operative periods (0–3 months, 3–6 months, 6–12 months, 12–24 and >24 months post-operation). Results. The index hip replacements consisted of 623,253 primaries with 2,705 subsequently revised for PJI, 14% within 3 months, 8% between 3–6 months, 14% between 6–12 months, 22% between 1–2 years and 42% ≥2 years after the index procedure. Risk factors for revision of PJI included male gender, high BMI, high ASA grade and younger age. Their effects were period-specific. Patients with chronic pulmonary disease, diabetes or dementia had high early risk of revision for PJI, as did patients operated for a fractured neck of femur (<3 months). Metal-on-metal bearings (>12 months) and lateral surgical approach (≥3 months) also influenced the mid- and long-term revision risk for PJI. No or modest associations were found with the operating surgeon grade, surgical volume and hospital surgical volume. Conclusion. The effects of patient, perioperative and healthcare system risk factors for PJI after primary hip replacement are time-dependent. Modifiable risk factors such as the type of surgical approach and bearing surface have also been found

Background. Over 96% of primary total hip replacements (THR) recorded in the National Joint Registry (NJR) are performed through a posterior or lateral surgical approach. There is no high quality evidence available to support the use of one approach over the other in primary THR and even less evidence when the outcome of revision THR is considered. Methods. Questionnaires were sent to 267 patients who had revision hip replacements between January 2006 and March 2010 for aseptic loosening. They rated their pain from 0–10, and used the Self-Administered Patient Satisfaction Scale (SAPS), Oxford Hip Score (OHS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Short form-12 (SF-12). Results. We performed 275 revision total hip replacements for aseptic loosening on patients in whom the primary operation details were available. Their mean age was 69 years (SD12) with 43% male and 57% right-sided procedures. 205 patients responded to our questionnaires (209/275 hips, 76%). Unfortunately 19 patients had died, 4 had dementia and 13 declined to participate. We were unable to contact a further 33.Grouping by approach, 20% (43/209) had primary and revision lateral approaches, 20% (43/209) had primary lateral and revision posterior and 60% (123/209) had both primary and revision via posterior approaches. The WOMAC and OHS were significantly better in patients who had a posterior approach for both primary and revision surgery, compared to those that did not (OHS p=0.028, WOMAC p=0.026). We found no significant differences in pain, satisfaction or health-related quality of life between the groups. Conclusions. Registry data may help further explore the relationship between surgical approach and outcome in revision hip surgery. A randomised controlled trial of the posterior versus lateral approach for revision surgery would provide a definitive answer. Level of Evidence. 2b - retrospective cohort study. Disclosures. No financial disclosures or conflicts of interests from any authors