Brushing Up on Cartilage Lubrication: Polyelectrolyte-Enhanced Tribological Rehydration.

This study presents new insights into the potential role of polyelectrolyte interfaces in regulating low friction and interstitial fluid pressurization of cartilage. Polymer brushes composed of hydrophilic 3-sulfopropyl methacrylate potassium salt (SPMK) tethered to a PEEK substrate (SPMK-g-PEEK) are a compelling biomimetic solution for interfacing with cartilage, inspired by the natural lubricating biopolyelectrolyte constituents of synovial fluid. These SPMK-g-PEEK surfaces exhibit a hydrated compliant layer approximately 5 µm thick, demonstrating the ability to maintain low friction coefficients (µ ∼ 0.01) across a wide speed range (0.1-200 mm/s) under physiological loads (0.75-1.2 MPa). A novel polyelectrolyte-enhanced tribological rehydration mechanism is elucidated, capable of recovering up to ∼12% cartilage strain and subsequently facilitating cartilage interstitial fluid recovery, under loads ranging from 0.25 to 2.21 MPa. This is attributed to the combined effects of fluid confinement within the contact gap and the enhanced elastohydrodynamic behavior of polymer brushes. Contrary to conventional theories that emphasize interstitial fluid pressurization in regulating cartilage lubrication, this work demonstrates that SPMK-g-PEEK's frictional behavior with cartilage is independent of these factors and provides unabating aqueous lubrication. Polyelectrolyte-enhanced tribological rehydration can occur within a static contact area and operates independently of known mechanisms of cartilage interstitial fluid recovery established for converging or migrating cartilage contacts. These findings challenge existing paradigms, proposing a novel polyelectrolyte-cartilage tribological mechanism not exclusively reliant on interstitial fluid pressurization or cartilage contact geometry. The implications of this research extend to a broader understanding of synovial joint lubrication, offering insights into the development of joint replacement materials that more accurately replicate the natural functionality of cartilage.

Soluble low affinity nerve growth factor receptor (sLNGFR) may regulate pain in knee osteoarthritis.

OBJECTIVES: Nerve growth factor ß (ß-NGF) is a protein which is important to the development of neurons particularly those involved in the transmission of pain and is central to the experience of pain in osteoarthritis (OA). Direct NGF antagonism has been shown to reduce OA pain but is associated with rapidly progressive OA. The aim of the study is to investigate the ability of soluble neurotrophin receptors in the NGF pathway to modulate pain in OA. METHODS: Synovial fluid (SF) was obtained from the knee joints of 43 subjects who underwent total knee arthroplasty. Visual analogue scale (VAS) pain scores were obtained prior to surgery. Customised-automated-ELISAs and commercial-ELISAs and LEGENDplex™ were used to measure soluble low-affinity nerve growth factor (LNGFR), soluble tropomyosin receptor kinase (TrkA), proNGF, ß-NGF, other neurotrophins (NT) and cytokines including inflammatory marker TNF-α. RESULTS: The VAS score positively correlated with ß-NGF (r=0.34) and there was positive association trend with neurotrophin-3 (NT-3), BDNF and negative association trend with ProNGF. sLNGFR positively correlated with VAS (r=0.33). The ß-NGF/soluble TrkA ratio showed a strong positive correlation with VAS (r=0.80). In contrast, there was no correlation between pain and the ß-NGF/sLNGFR ratio (r=-0.08). TNF-α positively correlated with ß-NGF (r=0.83), NT-3 (r=0.66), and brain-derived neurotrophic factor (BDNF) (r=0.50) and negatively with ProNGF (r= -0.74) and positively correlated with both soluble TrkA (r=0.62), sLNGFR (r=0.26). CONCLUSIONS: This study suggests that endogenous or cleaved sLNGFR, but not soluble TrkA may participate in OA pain modulation thus supporting further research into soluble LNGFR as a therapeutic target in OA.

Withholding of Hormone Replacement Therapy Prior to Total Joint Arthroplasty Surgery to Reduce the Risk of Postoperative Thromboembolic Events: Is It Justified?-A Systematic Review of Clinical Practice Guidelines.

BACKGROUND: Hormone replacement therapy (HRT), menopausal hormone therapy (MHT), and estrogen-containing medications are frequently withheld before elective lower limb arthroplasty, based on a perceived risk of venous thromboembolism (VTE). However, evidence linking HRT, MHT, and an increased VTE risk is equivocal. This systematic review evaluated the concordance of international clinical practice guidelines (CPGs) on the withholding of HRT or MHT. METHODS: The PubMed, Google Scholar, Cochrane, and Ovid databases were searched for CPGs for the preoperative, perioperative, and postoperative management of patients on HRT and MHT undergoing elective lower limb arthroplasty. This was supplemented by an internet search. There were 7 international CPGs in English, from Europe and North America, published between January 2000 and February 2023 reviewed against the Appraisal of Guidelines for Research & Evaluation Instrument (AGREE-II) criteria, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. RESULTS: The guidelines reviewed revealed a mixed picture on HRT or MHT withdrawal and use in arthroplasty, with some featuring detailed advice on the preoperative and postoperative management of HRT or MHT (Scottish Intercollegiate Guidelines Network), while others featured no guidance (American College of Chest Physicians). The evidence referenced in these guidelines highlighted studies showing HRT or MHT to play a limited role in increasing VTE risk, with most studies from the 1990s and 2000s. CONCLUSIONS: Based on current evidence, non-estrogen-containing transdermal HRT or MHT should not be withheld in patients undergoing elective joint arthroplasty, though further evidence is required to justify withholding estrogen-containing forms.

Characterisation and Expression of Osteogenic and Periodontal Markers of Bone Marrow Mesenchymal Stem Cells (BM-MSCs) from Diabetic Knee Joints.

Type 2 diabetes mellitus (T2DM) represents a significant health problem globally and is linked to a number of complications such as cardiovascular disease, bone fragility and periodontitis. Autologous bone marrow mesenchymal stem cells (BM-MSCs) are a promising therapeutic approach for bone and periodontal regeneration; however, the effect of T2DM on the expression of osteogenic and periodontal markers in BM-MSCs is not fully established. Furthermore, the effect of the presence of comorbidities such as diabetes and osteoarthritis on BM-MSCs is also yet to be investigated. In the present study, BM-MSCs were isolated from osteoarthritic knee joints of diabetic and nondiabetic donors. Both cell groups were compared for their clonogenicity, proliferation rates, MSC enumeration and expression of surface markers. Formation of calcified deposits and expression of osteogenic and periodontal markers were assessed after 1, 2 and 3 weeks of basal and osteogenic culture. Diabetic and nondiabetic BM-MSCs showed similar clonogenic and growth potentials along with comparable numbers of MSCs. However, diabetic BM-MSCs displayed lower expression of periostin (POSTN) and cementum protein 1 (CEMP-1) at Wk3 osteogenic and Wk1 basal cultures, respectively. BM-MSCs from T2DM patients might be suitable candidates for stem cell-based therapeutics. However, further investigations into these cells' behaviours in vitro and in vivo under inflammatory environments and hyperglycaemic conditions are still required.

Should Radiation Exposure be an Issue of Concern in Children With Multiple Trauma?

OBJECTIVE: The aims of this study were 3-fold: first, establish the level of radiation exposure experienced by the pediatric trauma patients; second, model the level of risk of developing fatal carcinogenesis; and third, test whether pattern of injury was predictive of the level of exposure. SUMMARY BACKGROUND DATA: There are certain conditions that cause children to be exposed to increased radiation, that is, scoliosis, where level of radiation exposure is known. The extent that children are exposed to radiation in the context of multiple traumas remains unclear. METHODS: Patients below the age of 16 years and with an Injury Severity Score (ISS) ≥10, treated by a Major Trauma Center for the period January 2008 to December 2018 were identified. The following data were extracted for the year following the patient's injury: number, doses, and type of radiological examination.The sex and age of the patient was taken into account in the calculation of the risk of developing a carcinogenesis. RESULTS: The median radiation dose of the 425 patients identified in the 12 months following injury, through both CT and radiographs, was 24.3 mSv. Modeling the predictive value of pattern of injury and other relevant clinical values, ISS was proportionately predictive of cumulative dose received. CONCLUSION: A proportion of younger polytrauma patients were exposed to high levels of radiation that in turn mean an increased risk of carcinogenesis. However, the ISS, age, injury pattern, and length of hospital stay are predictive of both risks, enabling monitoring and patient advisement of the risks.

Intra-articular therapies: patient preferences and professional practices in European countries.

To assess patient perspective and professional practice of intraarticular therapies (IATs) across Europe, an expert international multidisciplinary panel designed two open web-based surveys: one targeting people who had experienced at least two IATs (44 items); and one targeting health care providers (HCPs) (160 items). Surveys were disseminated via patient and professional associations and social media. A descriptive analysis was performed. The surveys were answered by 200 patients and 186 HCPs from 26 countries, showing that IAT is routinely performed by rheumatologists (97%) and orthopaedic surgeons (89%), with specific training being compulsory in a few countries. The most frequent indications for IAT are arthritis (76%), osteoarthritis (74%), crystal arthritis (71%) and bursitis (70%); the most frequently injected joints are knee (78%) and shoulder (70%); and the most used compounds are glucocorticoids. The majority of HCPs report informing patients about side-effects (73%), benefits (72%), and the nature of the procedure (72%), which coincides with 27% of patients reporting that they had not been informed about benefits or potential complications of IATs; 73% of patients had not been asked whether they wanted an anaesthetic. Few HCPs (10%) obtain written consent (56% get oral consent, being mandatory for 32%), a procedure deemed necessary by 41% of the patients. 50% of patients reported a clear benefit of IAT and 20% experienced complications including pain, impaired mobility, rashes, or swelling. In summary, the practice of IAT is variable across Europe, and although patients perceive it as relatively safe and usually effective procedure, some gaps were identified.

Medial stabilised total knee arthroplasty achieves comparable clinical outcomes when compared to other TKA designs: a systematic review and meta-analysis of the current literature.

PURPOSE: The purpose of this study was to perform a systematic review and meta-analysis to compare clinical and patient-reported outcome measures of medially stabilised (MS) TKA when compared to other TKA designs. METHODS: The Preferred Reporting Items for Systematic Review and Meta-Analyses algorithm was used. The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and EMCARE databases were searched to June 2020. Studies with a minimum of 12 months of follow-up comparing an MS TKA design to any other TKA design were included. The statistical analysis was completed using Review Manager (RevMan), Version 5.3. RESULTS: The 22 studies meeting the inclusion criteria included 3011 patients and 4102 TKAs. Overall Oxford Knee Scores were significantly better (p = 0.0007) for MS TKA, but there was no difference in the Forgotten Joint Scores (FJS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS)-Knee, KSS-Function, and range of motion between MS and non-MS TKA designs. Significant differences were noted for sub-group analyses; MS TKA showed significantly worse KSS-Knee (p = 0.02) and WOMAC (p = 0.03) scores when compared to Rotating Platform (RP) TKA while significantly better FJS (p = 0.002) and KSS-knee scores (p = 0.0001) when compared to cruciate-retaining (CR) TKA. CONCLUSION: This review and meta-analysis show that MS TKA designs result in both patient and clinical outcomes that are comparable to non-MS implants. These results suggest implant design alone may not provide further improvement in patient outcome following TKA, surgeons must consider other factors, such as alignment to achieve superior outcomes. LEVEL OF EVIDENCE: III.

Mortality After Postoperative Periprosthetic Fracture of the Femur After Hip Arthroplasty in the Last Decade: Meta-Analysis of 35 Cohort Studies Including 4841 Patients.

BACKGROUND: Postoperative periprosthetic fracture of the femur (POPFF) is associated with increased mortality. There is a lack of general estimates of mortality after POPFF and a need for higher-level evidence in this area. The aim of this study was to estimate mortality after POPFF using data reported in cohort studies from the last decade. METHODS: Literature search was conducted using Medline and Embase. The primary outcome was all-cause mortality during time as an inpatient, within 30 days, within 90 days, and within one year of POPFF. Mortality (95% confidence interval [CI]) was estimated using metaregression. RESULTS: A total of 4841 patients from 35 cohort studies were included. Study quality was generally low. The weighted mean follow-up was 2.3 years, and the most common POPFF was Vancouver B. The pooled mortality as an inpatient was 2.4% (95% CI 1.6% to 3.4%). The pooled mortality within 30 days was 3.3% (95% CI 2.0% to 5.0%). The pooled mortality within 90 days was 4.8% (95% CI 3.6% to 6.1%). The pooled mortality within one year was 13.4% (95% CI 11.9% to 14.8%). Mortality after POPFF was like that of neck of femur fracture up to 30 days, but better at one year. CONCLUSION: Mortality is like that experienced by patients after neck of femur fracture up to 30 days, but better at one year, which may represent the lower underlying risk of death in the POPFF cohort. These results may form the basis for evaluation of services treating POPFF in the future.

EULAR recommendations for intra-articular therapies.

OBJECTIVES: To establish evidence-based recommendations to guide health professionals using intra-articular therapies (IAT) in adult patients with peripheral arthropathies. METHODS: A multidisciplinary international task force established the objectives, users and scope and the need for background information, including systematic literature reviews) and two surveys addressed to healthcare providers and patients throughout Europe. The evidence was discussed in a face-to-face meeting, recommendations were formulated and subsequently voted for anonymously in a three-round Delphi process to obtain the final agreement. The level of evidence was assigned to each recommendation with the Oxford levels of evidence. RESULTS: Recommendations focus on practical aspects to guide health professionals before, during and after IAT in adult patients with peripheral arthropathies. Five overarching principles and 11 recommendations were established, addressing issues related to patient information, procedure and setting, accuracy, routine and special aseptic care, safety issues and precautions to be addressed in special populations, efficacy and safety of repeated joint injections, use of local anaesthetics and aftercare. CONCLUSION: We have developed the first evidence and expert opinion-based recommendations to guide health professionals using IAT. We hope that these recommendations will be included in different educational programmes, used by patient associations and put into practice via scientific societies to help improve uniformity and quality of care when performing IAT in peripheral adult joints.

Biomarkers of Joint Damage in Osteoarthritis: Current Status and Future Directions.

Osteoarthritis (OA) is a disease of the whole joint organ, characterized by the loss of cartilage, and structural changes in bone including the formation of osteophytes, causing disability and loss of function. It is also associated with systemic mediators and low-grade inflammation. Currently, there is negligible/no availability of specific biomarkers that can be used to facilitate the diagnosis and treatment of OA. The most unmet clinical need is, however, related to the monitoring of disease progression over a short period that can be used in clinical trials. In this review, the value of biomarkers identified over the past decade has been highlighted. These biomarkers are associated with the synthesis and breakdown of cartilage, including collagenous and noncollagenous biomarkers, inflammatory and anti-inflammatory biomarkers, expressed in the biological fluid such as serum, synovial fluid, and urine. Broad validation of novel and clinically applicable biomarkers and their involvement in the pathways are particularly needed for early-stage diagnosis, monitoring disease progression, and severity and examining new drugs to mitigate the effects of this highly prevalent and debilitating condition.

Consensus on pre-operative total knee replacement education and prehabilitation recommendations: a UK-based modified Delphi study.

BACKGROUND: Over 90,000 total knee replacement (TKR) procedures are performed annually in the United Kingdom (UK). Patients awaiting TKR face long delays whilst enduring severe pain and functional limitations. Almost 20% of patients who undergo TKR are not satisfied post-operatively. Optimising pre-operative TKR education and prehabilitation could help improve patient outcomes pre- and post-operatively; however, current pre-operative TKR care varies widely. Definitive evidence on the optimal content and delivery of pre-operative TKR care is lacking. This study aimed to develop evidence- and consensus-based recommendations on pre-operative TKR education and prehabilitation. METHODS: A UK-based, three-round, online modified Delphi study was conducted with a 60-member expert panel. All panellists had experience of TKR services as patients (n = 30) or professionals (n = 30). Round 1 included initial recommendations developed from a mixed methods rapid review. Panellists rated the importance of each item on a five-point Likert scale. Panellists could also suggest additional items in Round 1. Rounds 2 and 3 included all items from Round 1, new items suggested in Round 1 and charts summarising panellists' importance ratings from the preceding round. Free-text responses were analysed using content analysis. Quantitative data were analysed descriptively. All items rated as 'Important' or 'Very important' by at least 70% of all respondents in Round 3 were included in the final set of recommendations. RESULTS: Fifty-five panellists (92%) (patients n = 26; professionals n = 29) completed Round 3. Eighty-six recommendation items were included in Round 1. Fifteen new items were added in Round 2. Rounds 2 and 3 therefore included 101 items. Seventy-seven of these reached consensus in Round 3. Six items reached consensus amongst patient or professional panellists only in Round 3. The final set of recommendations comprises 34 education topics, 18 education delivery approaches, 10 exercise types, 13 exercise delivery approaches and two other treatments. CONCLUSIONS: This modified Delphi study developed a comprehensive set of recommendations that represent a useful resource for guiding decision-making on the content and delivery of pre-operative TKR education and prehabilitation. The recommendations will need to be interpreted and reviewed periodically in light of emerging evidence.

Childhood musculoskeletal impairment in Malawi from traumatic and non-traumatic causes: a population- based assessment using the key informant method.

BACKGROUND: Musculoskeletal impairment (MSI) in children is an under-recognised public health challenge. Although preventable, road injuries and other traumas continue to cause significant impairments to children worldwide. The study aimed to use the Key Informant Method (KIM) to assess prevalence and causes of MSI in children in two districts in Malawi, estimating the associated need for services provision, with a focus on traumatic aetiology. METHODS: The KIM was conducted in the districts of Thyolo (Southern Malawi) and Ntcheu (Central Malawi) in 2013. Five hundred key informants were trained to identify children who may have one of a range of MSI. The identified children were referred to a screening camp where they were examined by medical experts with standardised assessment protocols for diagnosing each form of impairment. RESULTS: 15,000 children were referred to screening camps. 7220 children were assessed (response rate 48%) for an impairment of whom 15.2% (1094) had an MSI. 13% of children developed MSI from trauma, while 54% had a neurological aetiology. For MSI of traumatic origin the most common body part affected was the elbow. Less than half of children with MSI (44.4%) were enrolled in school and none of these children attended schools with resources for disability. More than half of children with MSI (60%) had not received required services and 64% required further physical therapy. CONCLUSIONS: The KIM method was used to identify a high prevalence of MSI among children in two districts of Malawi and estimates an unmet need for dedicated MSI services.

Superior patient satisfaction in medial pivot as compared to posterior stabilized total knee arthroplasty: a prospective randomized study.

PURPOSE: Medial pivot (MP) total knee arthroplasty (TKA) aims to restore native knee kinematics due to highly conforming medial tibio-femoral articulation with survival comparable to contemporary knee designs. Posterior stabilized (PS) TKAs use cam-post mechanism to restore native femoral rollback. However, there is conflicting evidence regarding the reported patient satisfaction with MP TKA designs when compared to PS TKAs. The primary aim of this study is to compare the patient satisfaction between MP and PS TKA and the secondary aim is to establish potential reasons behind any differences in the outcomes noted between these two design philosophies. METHODS: In this IRB-approved single surgeon, single centre prospective RCT, 53 patients (mean age 62 years, 42 women) with comparable bilateral end-stage knee arthritis undergoing simultaneous bilateral TKA were randomized to receive MP TKA in one knee and PS TKA in the contralateral knee. At 4 years post-surgery, all patients were assessed using Knee Society Score (KSS)-Satisfaction and -Expectation scores, and Oxford Knee Score (OKS). In addition, all the patients underwent standardized radiological and in vivo kinematic assessment. RESULTS: Patients were more satisfied with the MP TKA as compared to PS TKA: mean KSS-Satisfaction [34.5 ± 3.05 in MP and 31.7 ± 3.16 in PS TKAs (p < 0.0001)] and mean KSS-Expectation scores [12.5 ± 1.39 in MP TKAs and 11.2 ± 1.41 in PS TKAs (p < 0.0001)]. No significant difference was noted in any other clinical outcomes. The in vivo kinematics of MP TKAs was significantly better than those of PS TKAs. CONCLUSION: MP TKAs provide superior patient satisfaction and patient expectations as compared to PS TKA. This may be related to better replication of natural knee kinematics with MP TKA. LEVEL OF EVIDENCE: I.

Early Recovery Following Total and Unicompartmental Knee Arthroplasty Assessed Using Novel Patient-Reported Measures.

BACKGROUND: The early postoperative recovery period following unicompartmental (UKA) and total knee arthroplasty (TKA) is an important area for research with increasingly sensitive metrics and new technologies. This study uses 2 recently developed patient-reported scores to compare the recovery following UKA and TKA. METHODS: Two consecutive cohorts of 37 UKAs and 33 TKAs completed the Oxford Arthroplasty Early Recovery Score (OARS) and the Oxford Arthroplasty Early Change Score (OACS) on days 1, 2, 3, 7, 14, and week 6. The Short Form-36 version 2 was also completed on weeks 1, 2, and 6. Improvements within cohorts and comparisons between cohorts were assessed. RESULTS: For both UKA and TKA the speed of recovery was rapid early on and then progressively decreased. At all time points, the UKA cohort reported similar or significantly better scores than the TKA cohort. The overall OARS (P < .001) showed that UKA recovered, shown as improvement on the OARS, 2-3 times faster than TKA. OARS subscales demonstrated that UKA had better Function/Mobility (P = .003) particularly early in the recovery, and better Nausea/Feeling Unwell (P < .001) and Fatigue/Sleep (P = .009) later in the recovery. UKA also had less pain at 2 weeks (P = .03). There was no significant difference between UKA and TKA OACS. UKA had significantly better scores in 3 of the 8 Short Form-36 domains, with the largest difference being in Role-Emotional (P = .003). CONCLUSION: The OARS is useful for the assessment of postoperative recovery. This study provides direct evidence that recovery following UKA is better and 2-3 times faster than following TKA. All differences may be explained by the less invasive nature of UKA.

Most unicompartmental knee replacement revisions could be avoided: a radiographic evaluation of revised Oxford knees in the National Joint Registry.

PURPOSE: The purpose of this study was to understand why the revision rate of unicompartmental knee replacement (UKR) in the National Joint Registry (NJR) is so high. Using radiographs, the appropriateness of patient selection for primary surgery, surgical technique, and indications for revision were determined. In addition, the alignment of the radiographs was assessed. METHODS: Oxford UKR registered with the NJR between 2006 and 2010 and subsequently revised were identified by the NJR. A blinded review was undertaken of pre-primary, post-primary, and pre-revision anteroposterior and lateral radiographs of a sample of 107 cases from multiple centres. RESULTS: The recommended indications were satisfied in 70%, with 29% not demonstrating bone-on-bone arthritis. Major technical errors, likely leading to revision, were seen in 6%. Pre-revision radiographs were malaligned and, therefore, difficult to interpret in 53%. No reason for revision was seen in 67%. Reasons for revision included lateral compartment arthritis (10%), tibial loosening (7%), bearing dislocation (7%), infection (6%), femoral loosening (3%), and peri-prosthetic fracture (2%, one femoral, one tibial). CONCLUSIONS: Only 20% of the revised UKR were implanted for the recommended indications, using appropriate surgical technique and had a mechanical problem necessitating revision. One-third of primary surgeries were undertaken in patients with early arthritis, which is contraindicated. Two-thirds were presumably revised for unexplained pain, which is not advised as it tends not to help the pain. This study suggests that variable and inappropriate indications for primary and revision surgery are responsible for the high rates of revision seen in registries. LEVEL OF EVIDENCE: III, Therapeutic study.

Do Trabecular Metal Acetabular Components Reduce the Risk of Rerevision After Revision THA Performed for Periprosthetic Joint Infection? A Study Using the NJR Data Set.

BACKGROUND: A single-center study of 144 THAs revised specifically for periprosthetic joint infection (PJI) observed that trabecular metal (TM) acetabular components had a reduced risk of rerevision for subsequent infection compared with non-TM implants. It was suggested that TM was protective against infection after revision and that TM may be useful when revising THAs for PJI. Three registry studies have subsequently assessed the effect of TM on future infection. In the National Joint Registry (NJR) for England and Wales, we earlier reported lower revision rates for infection when TM (versus non-TM) was used in primary THA, but no difference in rerevision rates for infection when TM was used for all-cause revision THAs. The latter findings in all-cause revisions were also confirmed in a study from the Swedish and Australian registries. It is possible that TM only reduces the risk of infection when it is specifically used for PJI revisions (rather than all-causes). However, to date, the registry analyses have not had large enough cohorts of such cases to assess this meaningfully. QUESTIONS/PURPOSES: (1) In revision THAs performed for PJI, are rerevision rates for all-cause acetabular indications lower with TM acetabular components compared with non-TM designs? (2) In revision THAs performed for PJI, are rerevision rates of any component for infection lower with TM acetabular components compared with non-TM designs? METHODS: A retrospective observational study was performed using NJR data from England and Wales, which is the world's largest arthroplasty registry and contains details of over two million joint replacement procedures. The registry achieves high levels of patient consent (92%) and linked procedures (ability to link serial procedures performed on the same patient and hip; 94%). Furthermore, recent validation studies have demonstrated that when revision procedures have been captured within the NJR, the data completion and accuracy were excellent. Of 11,988 revisions performed for all causes, 794 were performed for PJI in which the same cementless acetabular component produced by one manufacturer was used. Acetabular components were either TM (n = 541) or non-TM (n = 253). At baseline the two groups were comparable for sex, age, body mass index, and American Society of Anesthesiologists (ASA) grade. Outcomes after revision THA (rerevision for all-cause acetabular indications and rerevision of any component for infection) were compared between the groups using Fine and Gray regression analysis, which considers the competing mortality risk. Regression models were adjusted for the propensity score, with this score summarizing many of the potential patient and surgical confounding factors (age, sex, ASA grade, surgeon grade, approach, and type of revision procedure performed). RESULTS: There was no difference in 5-year cumulative acetabular component survival rates between TM (96.3%; 95% confidence interval [CI], 94%-98%) and non-TM components (94.4%, 95% CI, 90%-97%; subhazard ratio, 0.78, 95% CI, 0.37-1.65; p = 0.509). There was no difference in 5-year cumulative implant survival rates free from infection between TM (94.8%; 95% CI, 92%-97%) and non-TM components (94.4%, 95% CI, 90%-97%; subhazard ratio, 0.97, 95% CI, 0.48-1.96; p = 0.942). CONCLUSIONS: We found no evidence to support the notion that TM acetabular components used for PJI revisions reduced the subsequent risk of all-cause rerevision or the risk of rerevision for infection compared with non-TM implants from the same manufacturer. We therefore advise caution against recent claims that TM components may protect against infection. LEVEL OF EVIDENCE: Level III, therapeutic study.

Effect of Methylprednisolone in Periarticular Infiltration for Primary Total Knee Arthroplasty on Pain and Rehabilitation.

BACKGROUND: Optimal pain management after total knee arthroplasty (TKA) is important to ensure timely rehabilitation and patient satisfaction. This study examines the efficacy of adding corticosteroid in periarticular infiltration cocktail with relation to postoperative pain management and rehabilitation in patients undergoing simultaneous bilateral TKA. METHODS: Fifty patients with symptomatic end-stage bilateral knee osteoarthritis undergoing bilateral TKA under the same anesthetic were recruited. More painful knee was operated first, and the study solution containing ropivacaine, clonidine, epinephrine, and ketorolac with methylprednisolone was infiltrated in one knee and an identical mixture but without methylprednisolone was infiltrated in the second knee. Outcome measures included comparison of visual analogue scale on movement of each knee and range of motion achieved during the first three days after surgery. RESULTS: Differences in visual analogue scale score and range of motion at day one and three between the two groups of knees were significant (P < .05). Postoperative inflammation and the ability to straight leg raise showed better trends in the knees receiving prednisolone although this did not reach statistical significance. CONCLUSION: Addition of methylprednisolone to periarticular infiltration cocktail for patients undergoing TKA has significant influence on reduction of pain in the early postoperative period and patients are able to regain knee flexion more quickly.

Randomized Prospective Comparative Study of Adductor Canal Block vs Periarticular Infiltration on Early Functional Outcome After Unilateral Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is associated with significant postoperative pain. Effective pain relief is essential for early postoperative rehabilitation. Periarticular infiltration (PAI) and adductor canal block (ACB) have become popular modes of pain management after TKA. Our aim is to compare their efficacy and impact on early functional outcome in patients undergoing TKA. METHODS: A single-blinded randomized controlled trial, 100 patients undergoing unilateral primary TKA for symptomatic osteoarthritis were allocated to either of the 2 groups (50 in each arm): postoperative ultrasound-guided single shot of ACB (group A) or intraoperative PAI (group B). All patients underwent TKA without patella resurfacing under spinal anesthesia. Preoperative workup, surgical technique, and postoperative management were standardized for all the patients. Patients were assessed for pain using visual analogue scale at 6, 12, and 24 hours after surgery; hemoglobin level preoperatively and postoperatively on day 1 to calculate blood loss; hospital stay; tourniquet time; operative time; and postoperative complications by an independent observer blinded to the group allocation. RESULTS: Patients were matched for age, gender, American Society of Anesthesiologists grade, and deformity. Visual analogue scale (scale 0-10) between PAI and ACB at 6, 12, and 24 hours were significantly different (P < .05) with higher scores seen in patients with ACB at all time points. Tourniquet time and operative time were significantly longer in the PAI than ACB. No significant difference in hospital stay was observed. No complications occurred during the study. CONCLUSION: PAI achieves better pain control as compared to ACB in patients undergoing unilateral TKA.

No Threshold Exists for Recommending Revision Surgery in Metal-on-Metal Hip Arthroplasty Patients With Adverse Reactions to Metal Debris: A Retrospective Cohort Study of 346 Revisions.

BACKGROUND: Surgeons currently have difficulty when managing metal-on-metal hip arthroplasty (MoMHA) patients with adverse reactions to metal debris (ARMD). This stems from a lack of evidence, which is emphasized by the variability in the recommendations proposed by different worldwide regulatory authorities for considering MoMHA revision surgery. We investigated predictors of poor outcomes following MoMHA revision surgery performed for ARMD to help inform the revision threshold and type of reconstruction. METHODS: We retrospectively studied 346 MoMHA revisions for ARMD performed at 2 European centers. Preoperative (metal ions/imaging) and intraoperative (findings, components removed/implanted) factors were used to predict poor outcomes. Poor outcomes were postoperative complications (including re-revision), 90-day mortality, and poor Oxford Hip Score. RESULTS: Poor outcomes occurred in 38.5%. Shorter time (under 4 years) to revision surgery was the only preoperative predictor of poor outcomes (odds ratio [OR] = 2.12, confidence interval [CI] = 1.00-4.46). Prerevision metal ions and imaging did not influence outcomes. Single-component revisions (vs all-component revisions) increased the risk of poor outcomes (OR = 2.99, CI = 1.50-5.97). Intraoperative modifiable factors reducing the risk of poor outcomes included the posterior approach (OR = 0.22, CI = 0.10-0.49), revision head sizes ≥36 mm (vs <36 mm: OR = 0.37, CI = 0.18-0.77), ceramic-on-polyethylene revision bearings (OR vs ceramic-on-ceramic = 0.30, CI = 0.14-0.66), and metal-on-polyethylene revision bearings (OR vs ceramic-on-ceramic = 0.37, CI = 0.17-0.83). CONCLUSION: No threshold exists for recommending revision in MoMHA patients with ARMD. However postrevision outcomes were surgeon modifiable. Optimal outcomes may be achieved if surgeons use the posterior approach, revise all MoMHA components, and use ≥36 mm ceramic-on-polyethylene or metal-on-polyethylene articulations.

Risk Factors for Intraoperative Periprosthetic Femoral Fractures During Primary Total Hip Arthroplasty. An Analysis From the National Joint Registry for England and Wales and the Isle of Man.

BACKGROUND: The aim of this study is to estimate risk factors for intraoperative periprosthetic femoral fractures (IOPFF) and each anatomic subtype (calcar crack, trochanteric fracture, femoral shaft fracture) during primary total hip arthroplasty. METHODS: This retrospective cohort study included 793,823 primary total hip arthroplasties between 2004 and 2016. Multivariable regression modeling was used to estimate relative risk of patient, surgical, and implant factors for any IOPFF and for all anatomic subtypes of IOPFF. Clinically important interactions were assessed using multivariable regression. RESULTS: Patient factors significantly increasing the risk of fracture were female gender, American Society of Anesthesiologists grade 3 to 5, and preoperative diagnosis including avascular necrosis of the hip, previous trauma, inflammatory disease, pediatric disease, and previous infection. Overall risk of IOPFF associated with age was greatest in patients below 50 years and above 80 years. Risk of any fracture reduced with computer-guided surgery and in non-National Health Service hospitals. Nonposterior approaches increased the risk of shaft and trochanteric fracture only. Cementless implants significantly increased the risk of only calcar cracks and shaft fractures and not trochanteric fractures. CONCLUSION: Fracture risk increases in patients younger than 50 and older than 80 years, females, American Society of Anesthesiologists grade 3 to 5, and indications other than primary osteoarthritis. Large cumulative reduction in IOPFF risk may occur with use of cemented implants, posterior approach, and computer-guided surgery. LEVEL OF EVIDENCE: Level 3b (cohort study).