Epidemiology of revision hip replacement surgery in the UK over the past 15 years-an analysis from the National Joint Registry.

OBJECTIVES: To investigate trends in the incidence rate and main indication for revision hip replacement (rHR) over the past 15 years in the UK. DESIGN: Repeated national cross-sectional study from 2006 to 2020. SETTING/PARTICIPANTS: rHR procedures were identified from the National Joint Registry for England, Wales, Northern Ireland, the Isle of Man and the States of Guernsey. Population statistics were obtained from the Office for National Statistics. MAIN OUTCOME MEASURES: Crude incidence rates of rHR. RESULTS: The incidence rate of rHR doubled from 11 per 100 000 adults in 2006 (95% CI 10.7 to 11.3) to a peak of 22 per 100 000 adults (95% CI 22 to 23) in 2012, before falling to 17 per 100 000 adults in 2019 (95% CI 16 to 17) (24.5% decrease from peak). The incidence rate of rHR reduced by 39% in 2020 compared with 2019 (during the COVID-19 pandemic). The most frequent indications for rHR between 2006 and 2019 were loosening/lysis (27.8%), unexplained pain (15.1%) and dislocation/instability (14.7%). There were incremental increases in the annual number and incidence rates of rHR for fracture, infection, dislocation/instability and a decrease in rHR for aseptic loosening/lysis. CONCLUSIONS: The incidence rate of rHR doubled from 2006 to 2012, likely due to high early failure rates of metal-on-metal hip replacements. The incidence of rHR then decreased by approximately 25% from 2012 to 2019, followed by a large decrease during the COVID-19 pandemic. The decrease in the number of rHR performed for aseptic loosening/lysis may reflect improved wear and implant longevity. Increased healthcare resource will be required to care for the increasing numbers of patients undergoing rHR for fracture and infection.

Patient-Relevant Outcomes Following First Revision Total Knee Arthroplasty, by Diagnosis: An Analysis of Implant Survivorship, Mortality, Serious Medical Complications, and Patient-Reported Outcome Measures Utilizing the National Joint Registry Data Set.

BACKGROUND: The purpose of this study was to investigate patient-relevant outcomes following first revision total knee arthroplasties (rTKAs) performed for different indications. METHODS: This population-based cohort study utilized data from the United Kingdom National Joint Registry, Hospital Episode Statistics Admitted Patient Care, National Health Service Patient-Reported Outcome Measures, and the Civil Registrations of Death. Patients undergoing a first rTKA between January 1, 2009, and June 30, 2019, were included in our data set. Patient-relevant outcomes included implant survivorship (up to 11 years postoperatively), mortality and serious medical complications (up to 90 days postoperatively), and patient-reported outcome measures (at 6 months postoperatively). RESULTS: A total of 24,540 first rTKAs were analyzed. The patient population was 54% female and 62% White, with a mean age at the first rTKA of 69 years. At 2 years postoperatively, the cumulative incidence of re-revision surgery ranged from 2.7% (95% confidence interval [CI], 1.9% to 3.4%) following rTKA for progressive arthritis to 16.3% (95% CI, 15.2% to 17.4%) following rTKA for infection. The mortality rate at 90 days was highest following rTKA for fracture (3.6% [95% CI, 2.5% to 5.1%]) and for infection (1.8% [95% CI, 1.5% to 2.2%]) but was <0.5% for other indications. The rate of serious medical complications requiring hospital admission within 90 days was highest for patients treated for fracture (21.8% [95% CI, 17.9% to 26.3%]) or infection (12.5% [95% CI, 11.2% to 13.9%]) and was lowest for those treated for progressive arthritis (4.3% [95% CI, 3.3% to 5.5%]). Patients who underwent rTKA for stiffness or unexplained pain had some of the poorest postoperative joint function (mean Oxford Knee Score, 24 and 25 points, respectively) and had the lowest proportion of responders (48% and 55%, respectively). CONCLUSIONS: This study found large differences in patient-relevant outcomes among different indications for first rTKA. The rate of complications was highest following rTKA for fracture or infection. Although rTKA resulted in large improvements in joint function for most patients, those who underwent surgery for stiffness and unexplained pain had worse outcomes. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Systematic review highlights high risk of bias of clinical prediction models for blood transfusion in patients undergoing elective surgery.

BACKGROUND: Blood transfusion can be a lifesaving intervention after perioperative blood loss. Many prediction models have been developed to identify patients most likely to require blood transfusion during elective surgery, but it is unclear whether any are suitable for clinical practice. STUDY DESIGN AND SETTING: We conducted a systematic review, searching MEDLINE, Embase, PubMed, The Cochrane Library, Transfusion Evidence Library, Scopus, and Web of Science databases for studies reporting the development or validation of a blood transfusion prediction model in elective surgery patients between January 1, 2000 and June 30, 2021. We extracted study characteristics, discrimination performance (c-statistics) of final models, and data, which we used to perform risk of bias assessment using the Prediction model risk of bias assessment tool (PROBAST). RESULTS: We reviewed 66 studies (72 developed and 48 externally validated models). Pooled c-statistics of externally validated models ranged from 0.67 to 0.78. Most developed and validated models were at high risk of bias due to handling of predictors, validation methods, and too small sample sizes. CONCLUSION: Most blood transfusion prediction models are at high risk of bias and suffer from poor reporting and methodological quality, which must be addressed before they can be safely used in clinical practice.

Comparing the Results of Total Ankle Arthroplasty Vs Tibiotalar Fusion (Ankle Arthrodesis) in Patients with Ankle Osteoarthritis since 2006 to 2020- A Systematic Review.

Background: This study compares the outcomes of patients undergoing total ankle arthroplasty (TAA) and tibiotalar fusion (ankle arthrodesis) in patients with end-stage osteoarthritis. The primary outcome assessed was Patient Reported Outcome Measures (PROMS); secondary outcomes included the incidence of revision, re-operation, and complications. Methods: A systematic review of studies examining the outcomes of patients undergoing TAA and/or tibiotalar fusion from 2006 to 2020 was conducted. Individual cohort studies and randomized control trials were included. Outcomes were assessed at two and five years. Results: 21 studies were included: 16 arthroplasty (2,016 patients) and 5 arthrodesis (256 patients) studies. No significant difference in PROMS was evident two years post-surgery - American Orthopaedic Foot and Ankle Society (AOFAS) scores were 78.8 (95% CI-confidence interval: 76.6-80.8; n=1548) and 80.8 (95% CI: 80.1-81.5; n=206 patients) for the arthroplasty and arthrodesis groups respectively. Two years post-surgery the revision rates for the arthroplasty and arthrodesis groups were similar - 3.5% (n=9) and 3.7% (n=61) respectively (OR-odds ratio: 1.05; 95% CI: 0.51-2.13); however, the re-operation rate was 2.5 times higher for the arthroplasty group (12.2%) in comparison to the arthrodesis group (5.1%) (OR: 2.57; 95% CI: 1.43-4.62). Documented complications in the arthroplasty group were half those documented in the arthrodesis group two years post-surgery (OR: 0.53; 95% CI: 0.37-0.77). No arthrodesis studies were found which contained mean 5-year follow-up data within the study period. Conclusion: Despite recent developments in TAA design, we found no clear evidence as to their superiority over ankle arthrodesis when considering patient outcomes two years postoperatively. However, this conclusion could be debatable in some types of patients such as diabetic patients, posttraumatic patients and patients with stiff hindfoot and midfoot.

Utility of pre-operative haemoglobin concentration to guide peri-operative blood tests for hip and knee arthroplasty: A decision curve analysis.

OBJECTIVE: Assess the prognostic value of pre-operative haemoglobin concentration (Hb) for identifying patients who develop severe post-operative anaemia or require blood transfusion following primary total hip or knee, or unicompartmental knee arthroplasty (THA, TKA, UKA). BACKGROUND: Pre-operative group and save (G&S), and post-operative Hb measurement may be unnecessary for many patients undergoing hip and knee arthroplasty provided individuals at greatest risk of severe post-operative anaemia can be identified. METHODS AND MATERIALS: Patients undergoing THA, TKA, or UKA between 2011 and 2018 were included. Outcomes were post-operative Hb below 70 and 80 g/L, and peri-operative blood transfusion. Logistic regression assessed the association between pre-operative Hb and each outcome. Decision curve analysis compared strategies for selecting patients for G&S and post-operative Hb measurement. RESULTS: 10 015 THA, TKA and UKA procedures were performed in 8582 patients. The incidence of blood transfusion (4.5%) decreased during the study. Using procedure specific Hb thresholds to select patients for pre-operative G&S and post-operative Hb testing had a greater net benefit than selecting all patients, no patients, or patients with pre-operative anaemia. CONCLUSIONS: Pre-operative G&S and post-operative Hb measurement may not be indicated for UKA or TKA when adopting restrictive transfusion thresholds, provided clinicians accept a 0.1% risk of patients developing severe undiagnosed post-operative anaemia (Hb < 70 g/L). The decision to perform these blood tests for THA patients should be based on local institutional data and selection of acceptable risk thresholds.

Risk of Infection Associated With Administration of Intravenous Iron: A Systematic Review and Meta-analysis.

Importance: Intravenous iron is recommended by many clinical guidelines based largely on its effectiveness in reducing anemia. However, the association with important safety outcomes, such as infection, remains uncertain. Objective: To examine the risk of infection associated with intravenous iron compared with oral iron or no iron. Data Sources: Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for randomized clinical trials (RCTs) from 1966 to January 31, 2021. Ongoing trials were sought from ClinicalTrials.gov, CENTRAL, and the World Health Organization International Clinical Trials Search Registry Platform. Study Selection: Pairs of reviewers identified RCTs that compared intravenous iron with oral iron or no iron across all patient populations, excluding healthy volunteers. Nonrandomized studies published since January 1, 2007, were also included. A total of 312 full-text articles were assessed for eligibility. Data Extraction and Synthesis: Data extraction and risk of bias assessments were performed according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) and Cochrane recommendations, and the quality of evidence was assessed using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach. Two reviewers extracted data independently. A random-effects model was used to synthesize data from RCTs. A narrative synthesis was performed to characterize the reporting of infection. Main Outcomes and Measures: The primary outcome was risk of infection. Secondary outcomes included mortality, hospital length of stay, and changes in hemoglobin and red blood cell transfusion requirements. Measures of association were reported as risk ratios (RRs) or mean differences. Results: A total of 154 RCTs (32 920 participants) were included in the main analysis. Intravenous iron was associated with an increased risk of infection when compared with oral iron or no iron (RR, 1.17; 95% CI, 1.04-1.31; I2 = 37%; moderate certainty of evidence). Intravenous iron also was associated with an increase in hemoglobin (mean difference, 0.57 g/dL; 95% CI, 0.50-0.64 g/dL; I2 = 94%) and a reduction in the risk of requiring a red blood cell transfusion (RR, 0.93; 95% CI, 0.76-0.89; I2 = 15%) when compared with oral iron or no iron. There was no evidence of an effect on mortality or hospital length of stay. Conclusions and Relevance: In this large systematic review and meta-analysis, intravenous iron was associated with an increased risk of infection. Well-designed studies, using standardized definitions of infection, are required to understand the balance between this risk and the potential benefits.

The role of intraoperative cell salvage for musculoskeletal sarcoma surgery.

BACKGROUND: The efficacy and safety of cell salvage for musculoskeletal sarcoma surgery have not been reported, and concerns over re-infusion of tumour cells remain. This study aims to i) describe the intra-operative blood loss and cell salvage reinfusion volumes for lower limb sarcoma and pelvic sarcoma procedures ii) and explore whether there is evidence of tumour cells in reinfused blood. METHODS: Retrospective analysis of 109 consecutive surgical procedures for biopsy-proven sarcoma or bone metastasis performed between 1 July 2015 and 30 October 2019. Salvaged blood was processed and reinfused when intraoperative blood loss exceeded 500 ml. Primary bone tumour (n = 86(79%)) and metastasis (n = 23(21%) constituted the study group and surgeries were classified under hemipelvectomy (n = 43(39%)), lower limb endoprosthesis replacement (LLE) (n = 50(46%)) and wide excision surgery (WE) (n = 16(15%)). Microscopic examination of imprint cytology of leuco-depletion(LD) filters, and peripheral smear examination was performed for reinfused blood. RESULTS: Median (IQR) intra-operative blood loss was 1750 (600-3000) ml for hemipelvectomy, 850 (600-1200) ml for LLE, and 1000 (550-2000) ml for WE. Salvaged blood was re-infused in 102 of 109 (94%) patients. The mean (SD) volume of re-infusion was 445(4 2 5) ml for hemipelvectomy, 206(1 3 1) ml for LLE, and 184(1 0 6) ml for WE. In total, 64 of 109 (59%) patients received an allogeneic red blood transfusion within 72 h of surgery. Cytology analysis of imprints taken from the filtered blood available in 95(87%) patients and peripheral smear examination of reinfused blood available in 32(29%) patients did not reveal evidence of tumour cells on microscopic examination of any samples. CONCLUSION: Our study demonstrates that musculoskeletal sarcoma surgery is associated with significant blood loss, and cell salvage permits reinfusion of autologous blood in most patients. The cytological analysis did not reveal evidence of tumour cells in reinfused blood, consistent with other studies where cell salvage is used for cancer surgery.

Modifiable risk factors for mortality in revision total hip arthroplasty for periprosthetic fracture.

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

Rates of knee arthroplasty in patients with a history of arthroscopic chondroplasty: results from a retrospective cohort study utilising the National Hospital Episode Statistics for England.

OBJECTIVE: The purpose of this study was to analyse the rate of knee arthroplasty in the population of patients with a history of arthroscopic chondroplasty of the knee, in England, over 10 years, with comparison to general population data for patients without a history of chondroplasty. DESIGN: Retrospective cohort study. SETTING: English Hospital Episode Statistics (HES) data. PARTICIPANTS AND INTERVENTIONS: Patients undergoing arthroscopic chondroplasty in England between 2007/2008 and 2016/2017 were identified. Patients undergoing previous arthroscopic knee surgery or simultaneous cruciate ligament reconstruction or microfracture in the same knee were excluded. OUTCOMES: Patients subsequently undergoing a knee arthroplasty in the same knee were identified and mortality-adjusted survival analysis was performed (survival without undergoing knee arthroplasty). A Cox proportional hazards model was used to identify factors associated with knee arthroplasty. Relative risk of knee arthroplasty (total or partial) in comparison to the general population was determined. RESULTS: Through 2007 to 2017, 157 730 eligible chondroplasty patients were identified. Within 1 year, 5.91% (7984/135 197; 95% CI 5.78 to 6.03) underwent knee arthroplasty and 14.22% (8145/57 267; 95% CI 13.94 to 14.51) within 5 years. Patients aged over 30 years with a history of chondroplasty were 17.32 times (risk ratio; 95% CI 16.81 to 17.84) more likely to undergo arthroplasty than the general population without a history of chondroplasty. CONCLUSIONS: Patients with cartilage lesions of the knee, treated with arthroscopic chondroplasty, are at greater risk of subsequent knee arthroplasty than the general population and for a proportion of patients, there is insufficient benefit to prevent the need for knee arthroplasty within 1 to 5 years. These important new data will inform patients of the anticipated outcomes following this procedure. The risk in comparison to non-operative treatment remains unknown and there is an urgent need for a randomised clinical trial in this population.

Arthroscopic hip surgery compared with physiotherapy and activity modification for the treatment of symptomatic femoroacetabular impingement: multicentre randomised controlled trial.

OBJECTIVE: To compare arthroscopic hip surgery with physiotherapy and activity modification for improving patient reported outcome measures in patients with symptomatic femoroacetabular impingement (FAI). DESIGN: Two group parallel, assessor blinded, pragmatic randomised controlled trial. SETTING: Secondary and tertiary care centres across seven NHS England sites. PARTICIPANTS: 222 participants aged 18 to 60 years with symptomatic FAI confirmed clinically and with imaging (radiography or magnetic resonance imaging) were randomised (1:1) to receive arthroscopic hip surgery (n=112) or a programme of physiotherapy and activity modification (n=110). Exclusion criteria included previous surgery, completion of a physiotherapy programme targeting FAI within the preceding 12 months, established osteoarthritis (Kellgren-Lawrence grade ≥2), and hip dysplasia (centre-edge angle <20 degrees). INTERVENTIONS: Participants in the physiotherapy group received a goal based programme tailored to individual patient needs, with emphasis on improving core stability and movement control. A maximum of eight physiotherapy sessions were delivered over five months. Participants in the arthroscopic surgery group received surgery to excise the bone that impinged during hip movements, followed by routine postoperative care. MAIN OUTCOME MEASURES: The primary outcome measure was the hip outcome score activities of daily living subscale (HOS ADL) at eight months post-randomisation, with a minimum clinically important difference between groups of 9 points. Secondary outcome measures included additional patient reported outcome measures and clinical assessment. RESULTS: At eight months post-randomisation, data were available for 100 patients in the arthroscopic hip surgery group (89%) and 88 patients in the physiotherapy programme group (80%). Mean HOS ADL was 78.4 (95% confidence interval 74.4 to 82.3) for patients randomised to arthroscopic hip surgery and 69.2 (65.2 to 73.3) for patients randomised to the physiotherapy programme. After adjusting for baseline HOS ADL, age, sex, and study site, the mean HOS ADL was 10.0 points higher (6.4 to 13.6) in the arthroscopic hip surgery group compared with the physiotherapy programme group (P<0.001)). No serious adverse events were reported in either group. CONCLUSIONS: Patients with symptomatic FAI referred to secondary or tertiary care achieve superior outcomes with arthroscopic hip surgery than with physiotherapy and activity modification. TRIAL REGISTRATION: ClinicalTrials.gov NCT01893034.

What is the effect of perioperative intravenous iron therapy in patients undergoing non-elective surgery? A systematic review with meta-analysis and trial sequential analysis.

BACKGROUND: Guidelines to treat anaemia with intravenous (IV) iron have focused on elective surgical patients with little attention paid to those undergoing non-elective/emergency surgery. Whilst these patients may experience poor outcomes because of their presenting illness, observational data suggests that untreated anaemia may also be a contributing factor to poor outcomes. We conducted a systematic review to investigate the safety and efficacy of IV iron in patients undergoing non-elective surgery. METHODS: We followed a pre-defined review protocol and included randomised controlled trials (RCTs) in patients undergoing non-elective surgery who received IV iron. Primary outcomes were all-cause infection and mean difference in haemoglobin (Hb) at follow-up. Secondary outcomes included transfusion requirements, hospital length of stay (LOS), health-related quality of life (HRQoL), mortality and adverse events. RESULTS: Three RCTs (605 participants) were included in this systematic review of which two, in both hip fracture (HF) patients, provided data for meta-analysis. Both of these RCTs were at low risk of bias. We found no evidence of a difference in the risk of infection (RR 0.99, 95% CI 0.55 to 1.80, I 2 = 9%) or in the Hb concentration at 'short-term' (≤ 7 days) follow-up (mean difference - 0.32 g/L, 95% CI - 3.28 to 2.64, I 2 = 37%). IV iron did not reduce the risk of requiring a blood transfusion (RR 0.90, 95% CI 0.73 to 1.11, p = 0.46, I 2 = 0%), and we observed no difference in mortality, LOS or adverse events. One RCT reported on HRQoL and found no difference between treatment arms. CONCLUSION: We found no conclusive evidence of an effect of IV iron on clinically important outcomes in patients undergoing non-elective surgery. Further adequately powered trials to evaluate its benefit in emergency surgical specialties with a high burden of anaemia are warranted. TRIAL REGISTRATION: This systematic review was registered on PROSPERO (CRD42018096288).

External Fixation vs Intramedullary Nailing for Knee Arthrodesis After Failed Infected Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: The aim of this study is to compare intramedullary nailing with external fixation for knee arthrodesis after failed infected total knee arthroplasty (TKA). Primary outcome is radiographic union. Secondary outcomes include recurrent deep infection, revision arthrodesis, and amputation. METHODS: Systematic review and meta-analysis of studies comparing outcomes from intramedullary nailing and external fixation in patients with infected TKA undergoing arthrodesis procedures was performed. Randomized controlled trials and cohort studies were included. RESULTS: Intramedullary nailing achieves a significantly higher rate of radiographic union compared with external fixation (odds ratio [OR] 5.17, 95% confidence interval [CI] 2.74-9.75, P < .00001) at a mean follow-up of 44.22 months. There is no significant difference in the rate of recurrent deep infection (OR 0.91, 95% CI 0.38-2.15, P = .83) or amputation (OR 0.94, 95% CI 0.23-3.84, P = .93). The rate of revision arthrodesis procedures is significantly lower for intramedullary nailing compared with external fixation (OR 0.28, 95% CI 0.08-0.93, P = .04). CONCLUSION: Intramedullary nailing is more effective than external fixation with respect to several clinically important outcomes. Therefore, we recommend intramedullary nailing for achieving knee arthrodesis as a salvage procedure for infected TKA in the absence of specific indications for external fixation.

The Relationship Between Polyethylene Wear and Periprosthetic Osteolysis in Total Hip Arthroplasty at 12 Years in a Randomized Controlled Trial Cohort.

BACKGROUND: Polyethylene acetabular components are common in hip arthroplasty. Highly cross-linked polyethylene (HXLPE) has lower wear than ultra-high molecular weight polyethylene (UHMWPE). Evidence suggests that wear particles induce inflammation causing periprosthetic osteolysis contributing to implant loosening with wear rates of 0.05 mm/y were considered safe. We aimed to compare incidence and volume of periacetabular osteolysis between HXLPE and UHMWPE using computed tomography. METHODS: Initially, 54 hips in 53 patients were randomized to HXLPE or UHMWPE acetabular liner. At 10 years, 39 hips in 38 patients remained for the radiostereometric analysis' demonstrating significantly lower wear in the HXLPE group. At 12 years, 14 hips in 13 patients were lost to follow-up leaving 25 hips for computed tomography assessment. Images were reconstructed to detect osteolysis and where identified, areas were segmented and volumized. RESULTS: Osteolysis was observed in 8 patients, 7 from the UHMWPE group and only 1 from the HXLPE group (Fisher exact, P = .042). There was no correlation between the amount of polyethylene wear and osteolysis volume; however, the radiostereometric analysis-measured wear rate in patients with osteolysis from both groups was significantly higher than overall average wear rate. CONCLUSION: This data demonstrates lower incidence of periacetabular osteolysis in the HXLPE group of a small cohort. Although numbers are too low to estimate causation, in the context of lower wear in the HXLPE group, this finding supports the hypothesis that HXLPE may not elevate osteolysis risk, and hence does not suggest that HXLPE wear particles are more biologically active than those generated by earlier generations of polyethylene.

The Urgent Need for Evidence in Arthroscopic Meniscal Surgery.

BACKGROUND: Arthroscopic surgery of the knee is one of the most frequently performed orthopaedic procedures. One-third of these procedures are performed for meniscal injuries. It is essential that this commonly performed surgery be supported by robust evidence. PURPOSE: To compare the effectiveness of arthroscopic surgery for meniscal injuries in all populations. STUDY DESIGN: Systematic review. METHODS: An online search was conducted for randomized controlled trials (RCTs) and systematic reviews (SRs) that compared treatment options for meniscal injury. The following databases (inception to April 2015) were included in the search: CENTRAL; MEDLINE; EMBASE; NHS Evidence; National Guideline Clearing House, Database of Abstracts of Reviews of Effects, Health Technology Assessment; ISRCTN; Clinicaltrials.gov ; WHO trials platform. Only studies whose participants were selected on the basis of meniscal injury were included; no restrictions were placed on patient demographics. Two independent reviewers applied AMSTAR (A Measurement Tool to Assess Systematic Reviews) criteria for SRs and the Cochrane Collaboration risk-of-bias tool for RCTs. RESULTS: Nine RCTs and 8 SRs were included in the review. No difference was found between arthroscopic meniscal debridement compared with nonoperative management as a first-line treatment strategy for patients with knee pain and a degenerative meniscal tear (mean difference: Knee injury and Osteoarthritis Outcome Score, 1.6 [95% CI, -2.2 to 5.2], pain visual analog scale, -0.06 [95% CI, -0.28 to 0.15]). Some evidence was found to indicate that patients with resistant mechanical symptoms who initially fail nonoperative management may benefit from meniscal debridement No studies compared meniscal repair with meniscectomy or nonoperative management. Initial evidence suggested that meniscal transplant might be favorable in certain patient groups. CONCLUSION: Further evidence is required to determine which patient groups have good outcomes from each intervention. Given the current widespread use of arthroscopic meniscal surgeries, more research is urgently needed to support evidence-based practice in meniscal surgery in order to reduce the numbers of ineffective interventions and support potentially beneficial surgery.