Knee replacement

Towards an effective sensing technology to monitor micro-scale interface loosening of bioelectronic implants

Instrumented implants are being developed with a radically innovative design to significantly reduce revision surgeries. Although bone replacements are among the most prevalent surgeries performed worldwide, implant failure rate usually surpasses 10%. High sophisticated multifunctional bioelectronic implants are being researched to incorporate cosurface capacitive architectures with ability to deliver personalized electric stimuli to peri-implant target tissues. However, the ability of these architectures to detect bone-implant interface states has never been explored. Moreover, although more than forty technologies were already proposed to detect implant loosening, none is able to ensure effective monitoring of the bone-implant debonding, mainly during the early stages of loosening. This work shows, for the first time, that cosurface capacitive sensors are a promising technology to provide an effective monitoring of bone-implant interfaces during the daily living of patients. Indeed, in vitro experimental tests and simulation with computational models highlight that both striped and circular capacitive architectures are able to detect micro-scale and macro-scale interface bonding, debonding or loosening, mainly when bonding is weakening or loosening is occurring. The proposed cosurface technologies hold potential to implement highly effective and personalized sensing systems such that the performance of multifunctional bioelectronic implants can be strongly improved. Findings were reported open a new research line on sensing technologies for bioelectronic implants, which may conduct to great impacts in the coming years.

Knee Cartilage Thickness Differs Alongside Ages: A 3-T Magnetic Resonance Research Upon 2,481 Subjects via Deep Learning

Background: It was difficult to distinguish the cartilage thinning of an entire knee joint and to track the evolution of cartilage morphology alongside ages in the general population, which was of great significance for studying osteoarthritis until big imaging data and artificial intelligence are fused. The purposes of our study are (1) to explore the cartilage thickness in anatomical regions of the knee joint among a large collection of healthy knees, and (2) to investigate the relationship between the thinning pattern of the cartilages and the increasing ages. Methods: In this retrospective study, 2,481 healthy knees (subjects ranging from 15 to 64 years old, mean age: 35 ± 10 years) were recruited. With magnetic resonance images of knees acquired on a 3-T superconducting scanner, we automatically and precisely segmented the cartilage via deep learning and calculated the cartilage thickness in 14 anatomical regions. The thickness readings were compared using ANOVA by considering the factors of age, sex, and side. We further tracked the relationship between the thinning pattern of the cartilage thickness and the increasing ages by regression analysis. Results: The cartilage thickness was always thicker in the femur than corresponding regions in the tibia (p < 0.05). Regression analysis suggested cartilage thinning alongside ages in all regions (p < 0.05) except for medial and lateral anterior tibia in both females and males (p > 0.05). The thinning speed of men was faster than women in medial anterior and lateral anterior femur, yet slower in the medial patella (p < 0.05). Conclusion: We established the calculation method of cartilage thickness using big data and deep learning. We demonstrated that cartilage thickness differed across individual regions in the knee joint. Cartilage thinning alongside ages was identified, and the thinning pattern was consistent in the tibia while inconsistent in patellar and femoral between sexes. These findings provide a potential reference to detect cartilage anomaly.

The prevalence of posterolateral tibial baseplate overhang: An anatomical CT study

Introduction

Total Knee Arthroplasty (TKA) is used in patients with osteoarthritis who have failed conservative management to reduce pain, improve functional outcomes and ultimately quality of life. However, less than optimal patient satisfaction has led to continued improvements in design and technology of TKA. One factor that can limit patient satisfaction is postero-lateral overhang of the tibial baseplate. The purpose of our study is to utilize pre-operative CT scans to assess the prevalence of posterolateral tibial overhang with the use of a symmetric tibial baseplate component in a popular knee system with robotic assistance.

Methods

Ninety-eight (98) consecutive patients who underwent robotic-assisted total knee arthroplasty (TKA) were included in this study. Using both the most medial aspect of the tibial tubercle and the medial ⅓ of the tibial tubercle as reference points, we quantified the extent of posterolateral overhang when determining the rotation of the tibial component.

Results

Using the most medial aspect of the tibial tubercle as a reference point for rotation of the tibial baseplate, 63% of the instances of reviewed CT scans (369/588) had posterolateral overhang. Furthermore, 81% (406/588) had posterolateral overhang when using the medial ⅓ aspect of the tibial tubercle as the reference for rotation of the tibial baseplate. The average posterolateral tibial baseplate overhang was 1.5 mm (range 0-8 mm) when using the most medial aspect of the tibial tubercle and 2.4 mm (range 0-8 mm) when using the medial ⅓ tibial tubercle as the centering point for the tibial baseplate.

Discussion

Tibial baseplate overhang could lead to potential pain from irritation of soft tissues. To our knowledge, this is the first study that was able to valencquantify the amount of tibial baseplate overhang using pre-operative CT scans. Rotational alignment of the tibial baseplate needs to be balanced to ensure minimal lateral overhang while achieving sufficient external rotation of the tibial component. An asymmetric tibial component may provide a compromise in certain situations.

Level of evidence

Diagnostic level IV case series.

Application of 3D Printing-Assisted Articulating Spacer in Two-Stage Revision Surgery for Periprosthetic Infection after Total Knee Arthroplasty: A Retrospective Observational Study

Background

Bone cement spacers are widely used in two-stage revision surgeries for periprosthetic joint infection (PJI) after total knee arthroplasty. Current spacer design results in insufficient release of drugs; therefore, current spacers have low efficacy. In this study, we explored a set of alternative articular spacer using 3D printing technology. This novel spacer will increase effectiveness of revision surgery for PJI.

Methods

The spacer was designed using CAD software and constructed on site using 3D-printed silicone mold during debridement surgery. We carried out a retrospective study among patients undergoing treatment using traditional static and new articular spacers. Infection control rate, bone loss, difficulty of revision surgery, knee joint range of motion, function evaluation, and subjective satisfaction of the patients in the two groups were compared.

Results

Forty-two patients undergoing knee revision surgery between Jan 2014 and Nov 2019 were included in this study. Twenty-two patients were treated with static antibiotic cement spacers, whereas the other twenty patients were with treated with 3D printing-assisted antibiotic loaded articulating spacers. Patients in the articular group showed significantly lower bone loss on the femur site and tibial site compared with patients in the static group. In addition, patients in the articular group showed significantly less operation time, intraoperative blood loss, and improved knee function and patient overall satisfaction compared with patients in the static group.

Conclusions

The 3D printing-assisted articular spacer provides satisfactory range of motion during the interim period, prevents bone loss, facilitates second-stage reimplantation and postoperative rehabilitation, and results in low reinfection and complication rates.

What you need to know about kinematic alignment for total knee arthroplasty

This lecture outlines the various alignment philosophies for total knee arthroplasty (TKA). It is logical that our desire to improve clinical outcomes for TKA involves a more personalized and physiological implantation process that preserves each patient's anatomical features. We will take a deep dive into the kinematic alignment concept by describing its rationale, surgical steps and results. Kinematic implantation of TKA can be done reliably at a low cost and appears to achieve acceptable implant biomechanics. While its short-term clinical results are encouraging, it must be evaluated further. The thresholds for acceptable alignment (indications for restricted kinematic alignment) still need to be specified. LEVEL OF EVIDENCE: V; Expert opinion.

The Association of Calcium and Vitamin D Use With Implant Survival of Total Knee Arthroplasty: A Nationwide Population-Based Cohort Study

BACKGROUND

Calcium and vitamin D have been regarded as beneficial nutrients for bone metabolism that may affect survival of arthroplasties. However, the relationship between their use and revision rate of knee arthroplasty has not been evaluated. Thus, we investigated an association between calcium and vitamin D use and the revision rate after primary total knee arthroplasty.

METHODS

A nationwide population-based cohort study was conducted using the Korean National Health Insurance database. We included patients diagnosed with knee osteoarthritis and underwent primary total knee arthroplasty between 2009 and 2018. Risk for arthroplasty revision was estimated using a Cox proportional hazards model with time-dependent covariates. Log-rank test was used to assess survival of knee arthroplasty.

RESULTS

Out of 142,147 subjects, 28,403 were calcium and vitamin D users and 113,744 were never users. Calcium and vitamin D significantly reduced the revision risk with a 6-month drug use lag period (adjusted hazard ratio [aHR] 0.56, 95% confidence interval [CI] 0.45-0.70). Calcium and vitamin D combination use for more than 1 year was associated with reduced revision risks in both patients with periprosthetic joint infection (aHR 0.63, 95% CI 0.42-0.95) and patients without infection (aHR 0.70, 95% CI 0.54-0.91). Implant survival was significantly improved in calcium and vitamin D combination users for more than 1 year compared with never users (log-rank P < .001).

CONCLUSION

Combination use of calcium and vitamin D with a dose of 800 IU or greater for more than 1 year was associated with the greatest reduction in the risks for revision surgery after total knee arthroplasty.

Noninvasive diagnostic of periprosthetic joint infection by urinary peptide markers: A preliminary study

Previous immunohistochemical analyses revealed altered protein expression in the periprosthetic membranes of patients with periprosthetic joint infection (PJI). Proteins are degraded to peptides that may pass the blood-kidney barrier depending on their size. The aim of this study was to evaluate if PJI can be diagnosed based on the urinary peptide excretion pattern. Thirty patients undergoing removal of their hip or knee prostheses due to septic or aseptic loosening were enrolled. Specimen sampling was performed according to the MusculoSkeletal Infection Society criteria. A urinary sample was analyzed before surgery using capillary electrophoresis coupled with mass spectrometry. Peptides with differential urinary excretion between groups were used to establish a multimarker model. A total of 137 peptides were differentially excreted between the septic and aseptic groups. The majority of identified peptide markers were fragments of structural extracellular matrix proteins, potentially due to their origin from the periprosthetic membrane. A marker model with 83 peptides achieved the best diagnostic performance for diagnosing PJI with a sensitivity of 95%, a specificity of 90%, and an area under the curve of 0.96. The altered protein expression pattern in the periprosthetic membrane of PJI is most likely reflected in excreted urinary peptides. Thus, the diagnosis of PJI by urinary peptide markers seems to be a reasonable approach.

Which Oxford Knee Score level represents a satisfactory symptom state after undergoing a total knee replacement?

Background and purpose - Meaningful interpretation of postoperative Oxford Knee Score (OKS) levels is challenging. We established Patient Acceptable Symptoms State (PASS) and Treatment Failure (TF) values for the OKS in patients undergoing primary total knee replacement (TKR) in Denmark.Patients and methods - Data from patients undergoing primary TKR between February 2015 and January 2019 was extracted from the arthroplasty registry at the Copenhagen University Hospital, Hvidovre in Denmark. Data included 3, 12, and 24 months postoperative responses to the OKS and 2 anchor questions asking whether they considered their symptom state to be satisfactory, and if not, whether they considered the treatment to have failed. PASS and TF threshold values were calculated using the adjusted predictive modeling method. Non-parametric bootstrapping was used to derive 95% confidence intervals (CI).Results - Complete 3, 12, and 24 months postoperative data was obtained for 187 of 209 (89%), 884 of 915 (97%), and 575 of 586 (98%) patients, with median ages from 68 to 70 years (59 to 64% female). 72%, 77%, and 79% considered as having satisfactory symptoms, while 6%, 11%, and 11% considered the treatment to have failed, at 3, 12, and 24 months postoperatively, respectively. OKS PASS values (CI) were 27 (26-28), 30 (29-31), and 30 (29-31) at 3, 12, and 24 months postoperatively. TF values were 27 (26-28) and 27 (26-29) at 12 and 24 months postoperatively.Interpretation - The OKS PASS values can be used to guide the interpretation of TKR outcome and support quality assessment in institutional and national registries.

Do Knee Osteoarthritis Patterns Affect Patient-Reported Outcomes in Total Knee Arthroplasty? Results From an International Multicenter Prospective Study With 3-Year Follow-Up

BACKGROUND

The aim of this multicenter study is to answer (1) Does patellofemoral osteoarthritis (OA) affect preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) scores in total knee arthroplasty (TKA)? and (2) Do different OA patterns affect preoperative and postoperative KOOS scores in TKA?

METHODS

This international, multicenter prospective study examined 384 TKA patients. Compartmental OA was divided into (1) medial, (2) medial + patellofemoral, (3) lateral, (4) lateral + patellofemoral, (5) medial + lateral (bicompartmental), and (6) medial + lateral + patellofemoral (tricompartmental), based on preoperative anterior-posterior and lateral ± skyline radiographs with Kellgren-Lawrence grade III-IV and joint space width <2.5 mm. KOOS was collected preoperatively, 1 year postoperatively, and 3 years postoperatively. Higher KOOS score represented better clinical state, for example, higher KOOS Pain score indicated less pain.

RESULTS

Patellofemoral OA had no effect on preoperative KOOS scores (P > .15). Compared to medial ± patellofemoral OA patients, bicompartmental/tricompartmental OA patients had less preoperative pain (KOOS Pain 7.4, P = .03) and higher daily function (KOOS-ADL [Activities of Daily Living] 7.1, P = .05), and higher 1-year postoperative daily function (KOOS-ADL 9.2, P = .03) and sports activity (KOOS Sports & Recreation Function 15.0, P = .04), while lateral ± patellofemoral OA patients had more symptoms (KOOS-Symptoms 7.0, P < .01), more pain (KOOS-Pain 7.5, P = .01), lower daily function (KOOS-ADL 9.3, P < .01), and lower quality of life (KOOS-QOL 9.0, P = .04), at 3 years postoperatively.

CONCLUSION

Patellofemoral OA does not affect medial ± lateral OA patients' preoperative KOOS scores, challenging the importance of patellofemoral OA in TKA. Lateral ± patellofemoral OA patients have lower postoperative KOOS scores than medial/more progressed compartmental OA patients, indicating that patients with less common OA patterns present with unique surgical challenges. Further development of indications for and correct timing of TKA surgery in different patient subgroups is needed.

Risk factors of postoperative delirium in the knee and hip replacement patients: a systematic review and meta-analysis

BACKGROUND

The risk factors of postoperative delirium (POD), a serious while preventable complication, developed by patients undergoing knee and replacement surgery are still under investigation. In this systematic review and meta-analysis, we identified risk factors associated with POD in knee and hip replacement.

METHODS

PubMed, Ovid MEDLINE, and Ovid EMBASE were used to identify original researches. The studies evaluating the risk factors of POD after knee and hip replacement were reviewed, and the qualities of the included studies were assessed with Newcastle-Ottawa Scale. Data were extracted, pooled, and a meta-analysis was completed RESULT: Twenty-two studies were finally included with a total of 11934 patients who underwent knee or hip replacement and 1841 developed POD with an incidence of 17.6% (95% confidential interval (CI) 13.2-22.0%). Eighteen significant risk factors were identified including advanced age (odds ratio (OR) 1.15 95% CI 1.08-1.22), cognitive impairment (OR 6.84, 95% CI 3.27-14.33), history of cerebrovascular events (OR 2.51, 95% CI 1.28-4.91), knee replacement (OR 1.42, 95% CI 1.00-2.02), blood loss (standardized mean difference (SMD) 0.30, 95% CI 0.15-0.44), dementia (OR 3.09, 95% CI 2.10-4.56), neurologic disorders (OR 2.26, 95% CI 1.23-4.15), psychiatric illness (OR 2.74, 95% CI 1.34-5.62), and obstructive sleep apnea (OR 4.17, 95% CI 1.72-10.09) along with several comorbidity evaluation scores and laboratory markers.

CONCLUSION

We identified risk factors consistently associated with the incidence of POD in knee and hip replacement. Strategies and interventions should be implemented to the patients receiving knee or hip replacement with potential risk factors identified in this meta-analysis.

Impact of the numbers of injections of platelet rich plasma on the clinical outcomes in patients with knee osteoarthritis: A protocol for an updated network meta-analysis

BACKGROUND

Two published meta-analyses have investigated the effects of the number of injections of platelet rich plasma (PRP) on clinical outcomes in knee osteoarthritis patients, however conflicting findings were generated.

METHODS

We will systematically search PubMed, Embase, and China National Knowledgement Infrastructure (CNKI) to capture additional eligible studies. After screening citations, extracting essential data, assessing the risk of bias, we will use RevMan software and Open BUGS to perform head-to-head and network meta-analysis of pain alleviation and improvement of joint functionality, respectively.

DISCUSSION

Knee joint osteoarthritis (KOA) is the main cause of joint degeneration in elderly, which seriously reduces patients quality of life. Although intra-articular PRP has been extensively prescribed to treat KOA, a definitive conclusion about the appropriate number of injections has not yet been generated in published meta-analyses. The present updated network meta-analysis will comprehensively answer this question.

ETHICS AND DISSEMINATION

We will communicate our findings through participating in academic conferences or submiting it to be considered for publication in peer reviewed scholar journal.

INPLASY REGISTRATION NUMBER

We registered this protocol in International Plateform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) platform and obtained an identifier of INPLASY2020110043 (https://inplasy.com/inplasy-2020-11-0043/).

Unicondylar knee replacement versus total knee replacement for the treatment of medial knee osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Since the optimal surgery for isolated medial knee osteoarthritis (OA) is unclear, this study aimed at comparing the effectiveness of unicondylar knee replacement (UKR) with total knee replacement (TKR) for simple medial knee OA.

METHODS

Literature searches of PubMed, Embase, Web of Science, and the Cochrane Library were searched up to 1th April 2020. Only studies comparing UKR with TKR for isolated medial knee OA were included. Data collection and extraction, quality assessment, and data analyses were performed according to the Cochrane standards.

RESULTS

A total of 13 articles with 1888 patients were included, among which, 944 and 944 underwent UKR and TKR, respectively. The analyzed postoperative outcomes were mostly within 5 years of follow-up. The meta-analysis showed that UKR improved knee general function (P < 0.00001) and health (P = 0.02), moreover, reduced post-operative pain (P = 0.01) and complications (P < 0.05) more than TKR. There were no significant differences in postoperative revision (P = 0.252), high-activity arthroplasty score (HAAS) (P = 0.307) and Oxford knee score (OKS) (P = 0.15) between the two techniques.

CONCLUSIONS

The patients of UKR could achieve better clinical results than that of TKR, moreover, there were negligible differences between the two techniques in postoperative revision in the early and mid-term follow-up and surgeons should be aware of the important reasons for revision of UKR. Thus, UKR instead of TKR should be performed in patients with late-stage isolated medial knee OA.

Categorization of changes in the Oxford Knee Score after total knee replacement: an interpretive tool developed from a data set of 46,094 replacements

OBJECTIVES

The objective of the study was to create an interpretive categorical classification for the transition in the Oxford Knee Score (OKS) change score (ΔOKS) using the anchor-based method.

STUDY DESIGN AND SETTING

Registry data from 46,094 total knee replacements from the year 2014/15, were accessed via the Health and Social Care Information Center official website. Data included preoperative and 6-month follow-up OKS and response to the transition anchor question. Categories were determined using Gaussian approximation probability and k-fold cross-validation.

RESULTS

Four categories were identified with the corresponding ΔOKS intervals: "1. much better" (≥16), "2. a little better" (7-15), "3. about the same" (1-6), and "4. much worse" (≤0) based on the anchor questions' original five categories. The mean 10-fold cross-validation error was 0.35 OKS points (95% confidence interval 0.12 to 0.63). Sensitivity ranged from 0.34 to 0.68; specificity ranged from 0.74 to 0.95.

CONCLUSION

We have categorized the change score into a clinically meaningful classification. We argue it should be an addition to the continuous OKS outcome to contextualize the results in a way more applicable to the shared decision-making process and for interpreting research results.

Efficacy of Adductor Canal Block Combined With Additional Analgesic Methods for Postoperative Analgesia in Total Knee Arthroplasty: A Prospective, Double-Blind, Randomized Controlled Study

BACKGROUND

The aim of this study is to evaluate the efficacy of adductor canal block (ACB) combined with additional analgesic methods in total knee arthroplasty (TKA) and investigate whether blocking the sensory nerves that are distributed in the posterior and lateral aspect of knee could improve postoperative pain control.

METHODS

Two hundred scheduled patients for TKA were randomly allocated into 4 groups: Group A received ACB combined with iPACK (interspace between the popliteal artery and capsule of the knee) block and lateral femoral cutaneous nerve block (LFCNB); Group B received ACB combined with iPACK block; Group C received ACB combined with LFCNB; and Group D received ACB only. Postoperative pain score was the main primary outcome. Secondary outcomes included the morphine consumption and analgesic duration. Other outcomes included knee range of motion, quadriceps strength, ambulation, Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index physical function, timed up and go (TUG) test, and complications.

RESULTS

Groups A, B, and C had lower postoperative pain scores within 12 hours at rest and 8 hours with activity than Group D (P < .05). In addition, Group A had lower morphine consumption than both Group C (P < .05) and Group D (P < .01). Group A had the longest analgesic duration (19.21 ± 3.22 hours) among all groups. There were no significant differences among the groups in terms of mobility and complication after surgery.

CONCLUSION

Combining ACB with both iPACK and LFCNB is an effective method for decreasing early postoperative pain in TKA without increasing the complications or affecting the early rehabilitation.

Risk of venous thromboembolism in knee, hip and hand osteoarthritis: a general population-based cohort study

OBJECTIVES

Osteoarthritis is a leading cause of immobility and joint replacement, two strong risk factors for venous thromboembolism (VTE). We aimed to examine the relation of knee, hip and hand osteoarthritis to the risk of VTE and investigate joint replacement as a potential mediator.

METHODS

We conducted three cohort studies using data from The Health Improvement Network. Up to five individuals without osteoarthritis were matched to each case of incident knee (n=20 696), hip (n=10 411) or hand (n=6329) osteoarthritis by age, sex, entry time and body mass index. We examined the relation of osteoarthritis to VTE (pulmonary embolism and deep vein thrombosis) using a multivariable Cox proportional hazard model.

RESULTS

VTE developed in 327 individuals with knee osteoarthritis and 951 individuals without osteoarthritis (2.7 vs 2.0 per 1000 person-years), with multivariable-adjusted HR being 1.38 (95% CI 1.23 to 1.56). The indirect effect (HR) of knee osteoarthritis on VTE through knee replacement was 1.07 (95% CI 1.01 to 1.15), explaining 24.8% of its total effect on VTE. Risk of VTE was higher in hip osteoarthritis than non-osteoarthritis (3.3 vs 1.8 per 1000 person-years; multivariable-adjusted HR=1.83, 95% CI 1.56 to 2.13). The indirect effect through hip replacement yielded an HR of 1.14 (95% CI 1.04 to 1.25), explaining 28.1% of the total effect. No statistically significant difference in VTE risk was observed between hand osteoarthritis and non-osteoarthritis (1.5 vs 1.6 per 1000 person-years; multivariable-adjusted HR=0.88, 95% CI 0.67 to 1.16).

CONCLUSION

Our large population-based cohort study provides the first evidence that knee or hip osteoarthritis, but not hand osteoarthritis, was associated with an increased risk of VTE, and such an association was partially mediated through knee or hip replacement.

Impact of suspending minimum volume requirements for knee arthroplasty on hospitals in Germany: an uncontrolled before-after study

Background

In 2004, the Federal Joint Committee, supreme decision-making body in German healthcare, introduced minimum volume requirements (MVRQs) as a quality instrument. Since then, MVRQs were implemented for seven hospital procedures. This study evaluates the effect of a system-wide intermission of MVRQ for total knee arthroplasty (TKA), demanding 50 annual cases per hospital.

Methods

An uncontrolled before–after study based on federal-level data including the number of hospitals performing TKA, and TKA cases from the external hospital quality assurance programme in Germany (2004–2017). Bi- and multivariate analyses based on hospital-level secondary data of TKA cases and TKA quality indicators extracted from hospital quality reports in Germany (2006–2014).

Results

The number of TKAs performed in Germany decreased by 11% after suspending the TKA-MVRQ in 2011, and rose by 13% after its reintroduction in 2015. The number of hospitals with less than 50 cases rose from 10 to 25% and their case share from 2 to 5.5% during suspension. Change in hospital volume after the suspension of TKA-MVRQ was not associated with hospital size, ownership, or region. All four evaluable quality indicators increased significantly in the year after their first public reporting. Compared to hospitals meeting the TKA-MVRQ, three indicators show slight but statistically significant better quality in hospitals below the TKA-MVRQ.

Conclusions

In Germany, TKA-MVRQs seem to induce in-hospital caseload adjustments rather than foster regional inter-hospital case transfers as intended.

Outpatient physiotherapy versus home-based rehabilitation for patients at risk of poor outcomes after knee arthroplasty: CORKA RCT

BACKGROUND

Over 100,000 primary knee arthroplasty operations are undertaken annually in the UK. Around 15-30% of patients do not report a good outcome. Better rehabilitation strategies may improve patient-reported outcomes.

OBJECTIVES

To compare the outcomes from a traditional outpatient physiotherapy model with those from a home-based rehabilitation programme for people assessed as being at risk of a poor outcome after knee arthroplasty.

DESIGN

An individually randomised, two-arm controlled trial with a blinded outcome assessment, a parallel health economic evaluation and a nested qualitative study.

SETTING

The trial took place in 14 NHS physiotherapy departments.

PARTICIPANTS

People identified as being at high risk of a poor outcome after knee arthroplasty.

INTERVENTIONS

A multicomponent home-based rehabilitation package delivered by rehabilitation assistants with supervision from qualified therapists compared with usual-care outpatient physiotherapy.

MAIN OUTCOME MEASURES

The primary outcome was the Late Life Function and Disability Instrument at 12 months. Secondary outcomes were the Oxford Knee Score (a disease-specific measure of function); Knee injury and Osteoarthritis Outcome Score; Quality of Life subscale; Physical Activity Scale for the Elderly; EuroQol-5 Dimensions, five-level version; and physical function assessed using the Figure-of-8 Walk Test, 30-Second Chair Stand Test and Single Leg Stance. Data on the use of health-care services, time off work and informal care were collected using participant diaries.

RESULTS

In total, 621 participants were randomised. A total of 309 participants were assigned to the COmmunity based Rehabilitation after Knee Arthroplasty (CORKA) home-based rehabilitation programme, receiving a median of five treatment sessions (interquartile range 4-7 sessions). A total of 312 participants were assigned to usual care, receiving a median of four sessions (interquartile range 2-6 sessions). The primary outcome, Late Life Function and Disability Instrument function total score at 12 months, was collected for 279 participants (89%) in the home-based CORKA group and 287 participants (92%) in the usual-care group. No clinically or statistically significant difference was found between the groups (intention-to-treat adjusted difference 0.49 points, 95% confidence interval -0.89 to 1.88 points; p = 0.48). There were no statistically significant differences between the groups in any of the patient-reported or physical secondary outcome measures at 6 or 12 months post randomisation. The health economic analysis found that the CORKA intervention was cheaper to provide than usual care (£66 less per participant). Total societal costs (combining health-care costs and other costs) were lower for the CORKA intervention than usual care (£316 less per participant). Adopting a societal perspective, CORKA had a 75% probability of being cost-effective at a threshold of £30,000 per quality-adjusted life-year. Adopting the narrower health and social care perspective, CORKA had a 43% probability of being cost-effective at the same threshold.

LIMITATIONS

The interventions were of short duration and were set within current commissioning guidance for UK physiotherapy. Participants and treating therapists could not be blinded.

CONCLUSIONS

This randomised controlled trial found no important differences in outcomes when post-arthroplasty rehabilitation was delivered using a home-based, rehabilitation assistant-delivered rehabilitation package or a traditional outpatient model. However, the health economic evaluation found that when adopting a societal perspective, the CORKA home-based intervention was cost-saving and more effective than, and thus dominant over, usual care, owing to reduced time away from paid employment for this group. Further research could look at identifying the risk of poor outcome and further evaluation of a cost-effective treatment, including the workforce model to deliver it.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13517704.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 65. See the NIHR Journals Library website for further project information.

Semixup: In- and Out-of-Manifold Regularization for Deep Semi-Supervised Knee Osteoarthritis Severity Grading From Plain Radiographs

Knee osteoarthritis (OA) is one of the highest disability factors in the world. This musculoskeletal disorder is assessed from clinical symptoms, and typically confirmed via radiographic assessment. This visual assessment done by a radiologist requires experience, and suffers from moderate to high inter-observer variability. The recent literature has shown that deep learning methods can reliably perform the OA severity assessment according to the gold standard Kellgren-Lawrence (KL) grading system. However, these methods require large amounts of labeled data, which are costly to obtain. In this study, we propose the Semixup algorithm, a semi-supervised learning (SSL) approach to leverage unlabeled data. Semixup relies on consistency regularization using in- and out-of-manifold samples, together with interpolated consistency. On an independent test set, our method significantly outperformed other state-of-the-art SSL methods in most cases. Finally, when compared to a well-tuned fully supervised baseline that yielded a balanced accuracy (BA) of 70.9 ± 0.8% on the test set, Semixup had comparable performance - BA of 71 ± 0.8% ( p=0.368 ) while requiring 6 times less labeled data. These results show that our proposed SSL method allows building fully automatic OA severity assessment tools with datasets that are available outside research settings.

In vitro effects of cobalt and chromium nanoparticles on human platelet function

Nanoparticles (NPs) are released from orthopedic and neurosurgical prostheses and can interact with a number of blood components once in the bloodstream. Potential toxic effects of Co and Cr NPs on blood platelets have not been thoroughly investigated. The aim of this study was to analyze the effect of Co and Cr NPs on platelet function in vitro. The ability of the tested NPs to induce platelet activation and aggregation was measured using light transmission aggregometry, flow cytometry, and quartz crystal balance with dissipation (QCM-D). This was confirmed by transmission electron microscopy (TEM), scanning electron microscopy, and optical and immunofluorescence microscopy. Perfusion of QCM-D sensor crystals with platelet-rich-plasma in the presence of Co 28 nm, CoO 50 nm, Co₂O₃ 50 nm, Co₃O₄ 30-50nm, Cr 35-45nm, Cr₂O₃ 60 nm NPs (0.5-5.0 µg/mL) resulted in significant changes in frequency and dissipation, indicating that these NPs caused platelet microaggregation. Transmission electron microscopy also revealed that Cr NPs led to platelet swelling and lysis. Our study shows that both Co and Cr NPs affect platelet function in vitro with two distinct mechanisms. While Co NPs result in standard platelet aggregation, Cr NPs cause both platelet aggregation and decreased platelet membrane integrity and lysis. Based on these findings, monitoring serum NP levels and platelet-mediated hemostasis can be advised in patients with metal-on-metal Co-Cr prostheses.

Nepetin inhibits osteoclastogenesis by inhibiting RANKL-induced activation of NF-κB and MAPK signalling pathway, and autophagy

Aseptic prosthetic loosening due to wear particle-induced inflammatory osteolysis is the main cause of failure for artificial joint replacement. The inflammatory response and the production of pro-osteoclastic factors lead to elevation of osteoclast formation and excessive activity results in extensive bone destruction around the bone-implant interface. Here we showed that Nepetin, a natural bioactive flavonoid with proven anti-inflammatory and anti-proliferative properties, potently inhibited RANKL-induced osteoclast differentiation, formation and bone resorption in vitro, and protected mice against the deleterious effects of titanium particle-induced calvarial osteolysis in vivo. Mechanistically, Nepetin attenuated RANKL-induced activation of NF-κB and MAPK signalling pathways and TRAF6-dependent ubiquitination of Beclin 1 which is necessary for the induction of autophagy. In brief, our study demonstrates the potential therapeutic application of Nepetin against osteoclast-mediated osteolytic diseases.

Non-surgical management of knee osteoarthritis: comparison of ESCEO and OARSI 2019 guidelines

Knee osteoarthritis (OA) is a heterogeneous disease associated with substantial effects on quality of life, and its clinical management is difficult. Among the several available guidelines for the management of knee OA, those from OARSI and ESCEO were updated in 2019. Here, we examine the similarities and differences between these two guidelines and provide a narrative to help guide health-care providers through the complexities of non-surgical management of knee OA. OARSI and ESCEO both recommend education, structured exercise and weight loss as core treatments, topical NSAIDs as first-line treatments and oral NSAIDs and intra-articular injections for persistent pain. Low-dose, short-term acetaminophen, pharmaceutical grade glucosamine and chondroitin sulfate are recommended by ESCEO whereas OARSI strongly recommends against their use (including all glucosamine and chondroitin formulations). Despite this difference, the two guidelines are consistent in the majority of their recommendations and provide useful treatment recommendations for individuals with OA and health-care providers.

Continuous adductor canal block provides better performance after total knee arthroplasty compared with the single-shot adductor canal block?: An updated meta-analysis of randomized controlled trials

BACKGROUND

Adductor canal block (ACB) has emerged as an attractive alternative for femoral nerve blocks (FNB) as the peripheral nerve block of choice for total knee arthroplasty (TKA), preserving quadriceps motor function while providing analgesia comparable to FNB. However, its optimal application for TKA remains controversial. The objective of this meta-analysis was to compare continuous-injection ACB (CACB) vs single-injection ACB (SACB) for postoperative pain control in patients undergoing TKA.

METHODS

This study attempts to identify the available and relevant randomized controlled trials (RCTs) regarding the analgesic effects of CACB compared to SACB in patients undergoing TKA according to electronic databases, including PubMed, Medline, Web of Science, EMbase, and the Cochrane Library, up to September 2019. Primary outcomes in this regard included the use of a visual analogue scale (VAS) pain score with rest or activity, while secondary outcomes were cumulative opioid consumption, length of hospital stay (LOS), complications of vomiting and nausea, and rescue analgesia. The corresponding data were analyzed using RevMan v5.3.

ETHICAL REVIEW

Because all of the data used in this systematic review and meta-analysis has been published, the ethical approval was not necessary RESULTS:: This research included 9 studies comprised of 739 patients. The analyzed outcomes demonstrated that patients who received CACB had a better at rest-VAS scores at 4 hours (P = .007), 8 hors (P < .0001), 12 hours (P < .0001), 24 hours (P = .02), mobilization-VAS score at 48 hours (P < .0001), and rescue analgesia (P = .03) than those who underwent SACB. Nevertheless, no significant differences were present between the 2 strategies in terms of pain VAS scores 48 hours at rest (P = .23) and 24 hours at mobilization (P = .10), complications of vomiting and nausea (P = .42), and length of hospital stay (P = .09).

CONCLUSION

This meta-analysis indicated that CACB is superior to SACB in regard to analgesic effect following TKA. However, due to the variation of the included studies, no firm conclusions can be drawn. Further investigations into RCT are required for verification.

Modeling the impact of obesity on cost of hip and knee arthroplasty

PURPOSE

This study aimed to determine the proportions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) attributable to obesity in Ireland and the associated hospital costs.

METHODS

Sex- and age-specific numbers of primary TKA and THA procedures and length of stay were estimated using Irish population data from the Central Statistics Office (sex and age) and data from the national Hospital Inpatient Enquiry (numbers of TKA and THA procedures, length of stay, diagnostic-related group codes, sex, and age). Population attributable fractions of TKA and THA related to obesity were calculated using relative risks for different weight groups obtained from published literature. Nationally representative weight and height data were available from the 2015 Healthy Ireland Survey (n = 6142) and extrapolated to the Irish population. Diagnostic-related group tariffs from the Healthcare Pricing Office were used to estimate hospital costs of TKA and THA.

RESULTS

In 2015, 2296 TKA and 3411 THA procedures were performed in public hospitals in Ireland. Of those procedures, 43% of TKA and 20% of THA were attributable to obesity. This equates to €16.0 million out of €52.1 million of TKA- and THA-related hospital costs.

CONCLUSIONS

Effective obesity control has potential to decrease the demand for joint replacements and associated costs.

Targeting rehabilitation to improve outcomes after total knee arthroplasty in patients at risk of poor outcomes: randomised controlled trial

OBJECTIVE

To evaluate whether a progressive course of outpatient physiotherapy offers superior outcomes to a single physiotherapy review and home exercise based intervention when targeted at patients with a predicted poor outcome after total knee arthroplasty.

DESIGN

Parallel group randomised controlled trial.

SETTING

13 secondary and tertiary care centres in the UK providing postoperative physiotherapy.

PARTICIPANTS

334 participants with knee osteoarthritis who were defined as at risk of a poor outcome after total knee arthroplasty, based on the Oxford knee score, at six weeks postoperatively. 163 were allocated to therapist led outpatient rehabilitation and 171 to a home exercise based protocol.

INTERVENTIONS

All participants were reviewed by a physiotherapist and commenced 18 sessions of rehabilitation over six weeks, either as therapist led outpatient rehabilitation (progressive goal oriented functional rehabilitation protocol, modified weekly in one-one contact sessions) or as physiotherapy review followed by a home exercise based regimen (without progressive input from a physiotherapist).

MAIN OUTCOME MEASURES

Primary outcome was Oxford knee score at 52 weeks, with a 4 point difference between groups considered to be clinically meaningful. Secondary outcomes included additional patient reported outcome measures of pain and function at 14, 26, and 52 weeks post-surgery.

RESULTS

334 patients were randomised. Eight were lost to follow-up. Intervention compliance was more than 85%. The between group difference in Oxford knee score at 52 weeks was 1.91 (95% confidence interval -0.18 to 3.99) points, favouring the outpatient rehabilitation arm (P=0.07). When all time point data were analysed, the between group difference in Oxford knee score was a non-clinically meaningful 2.25 points (0.61 to 3.90, P=0.01). No between group differences were found for secondary outcomes of average pain (0.25 points, -0.78 to 0.28, P=0.36) or worst pain (0.22 points, -0.71 to 0.41, P=0.50) at 52 weeks or earlier time points, or of satisfaction with outcome (odds ratio 1.07, 95% confidence interval 0.71 to 1.62, P=0.75) or post-intervention function (4.64 seconds, 95% confidence interval -14.25 to 4.96, P=0.34).

CONCLUSIONS

Outpatient therapist led rehabilitation was not superior to a single physiotherapist review and home exercise based regimen in patients at risk of poor outcomes after total knee arthroplasty. No clinically relevant differences were observed across primary or secondary outcome measures.

TRIALS REGISTRATION

Current Controlled Trials ISRCTN23357609 and ClinicalTrials.gov NCT01849445.

Cervical spine degenerative disease is an independent risk factor for increased revision rate following total knee arthroplasty

INTRODUCTION

The relationship between cervical degenerative pathology and total knee arthroplasty (TKA) revision rates is not well understood. The aim of the study was to determine whether cervical spine degenerative diseases have a role in complications following TKA within 2 years.

METHODS

Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2007-2017. Patients who had a primary TKA were identified using Current Procedural Terminology (CPT) code 27,447, and patients with degenerative cervical disease were identified using CPT and International Classification of Diseases (ICD) codes. Data on patients' demographics, comorbidities and postoperative complications were recorded and analyzed with univariate and multivariate analysis with significance set at p < 0.05. A Kaplan-Meier analysis was conducted to estimate the 1- and 2-year rates of survival free from revision.

RESULTS

A total of 81,873 patients were included in this study. Following multivariate analysis, cervical spine degenerative disease patients were at increased risk of all-cause revision surgery following 1 year (OR: 1.342 95% CI: 1.149-1.569; p < 0.001) and 2 year (OR: 1.338; 95% CI: 1.184-1.512; p < 0.001). At 2 years, patients with cervical spine degenerative disease had a survival rate of 97.7%, while the survival rate was 99.2% among the non-cervical degenerative cohort.

CONCLUSIONS

Based on these results, patients with cervical spine degenerative pathology should be counseled that their spinal pathology may impair outcomes following TKA.

A multifunctional silk coating on additively manufactured porous titanium to prevent implant-associated infection and stimulate bone regeneration

Despite tremendous progress in the design and manufacturing of metallic implants, they do not outlive the patient. To illustrate, more than half of hip replacements will fail, mainly due to implant infection and loosening. Surface engineering approaches and, in particular, coatings can facilitate implant bio-functionality via the recruitment of more host cells for new bone formation and inhibition of bacterial colonization. Here, we used electrophoretic deposition to apply a silk fibroin solution consisting of tricalcium phosphate (TCP) and vancomycin as a coating on the surface of additively-manufactured porous titanium. Furthermore, the surface properties of the coatings developed and the release kinetics of the vancomycin were studied to evaluate the applied coating. The in vitro antibacterial behavior of the multifunctional coating, as well as the cell viability and osteogenic differentiation of the MC3T3-E1 cell line were extensively studied. The biomaterials developed exhibited an antibacterial behavior with a reduction of up to four orders of magnitude in both planktonic and adherent bacteria for 6 h and 1 d. A live-dead assay, the Alamar Blue activity, the DNA content, and cytoskeleton staining demonstrated a significant increase in the cell density of the coated groups versus the as-manufactured ones. The significantly enhanced calcium deposition and the increase in mineralization for the groups with TCP after 21 and 28 d, respectively, demonstrate upregulation of the MC3T3 cells' osteogenic differentiation. Our results collectively show that the multifunctional coating studied here can be potentially used to develop a new generation of orthopedic implants.

Occupation and risk of knee osteoarthritis and knee replacement: A longitudinal, multiple-cohort study

OBJECTIVES

To examine the effect of occupation on knee osteoarthritis (OA) and total knee replacement (TKR) in working-aged adults.

METHODS

We used longitudinal data from the Chingford, Osteoarthritis Initiative (OAI) and Multicentre Osteoarthritis (MOST) studies. Participants with musculoskeletal disorders and/or a history of knee-related surgery were excluded. Participants were followed for up to 19-years (Chingford), 96-months (OAI) and 60-months (MOST) for incident outcomes including radiographic knee OA (RKOA), symptomatic RKOA and TKR. In those with baseline RKOA, progression was defined as the time from RKOA incidence to primary TKR. Occupational job categories and work-place physical activities were assigned to levels of workload. Logistic regression was used to examine the relationship between workload and incident outcomes with survival analyses used to assess progression (reference group: sedentary occupations).

RESULTS

Heavy manual occupations were associated with a 2-fold increased risk (OR: 2.07, 95% CI 1.03 to 4.15) of incident RKOA in the OAI only. Men working in heavy manual occupations in MOST (2.7, 95% CI 1.17 to 6.26) and light manual occupations in OAI (2.00, 95% CI 1.09 to 3.68) had a 2-fold increased risk of incident RKOA. No association was observed among women. Increasing workload was associated with an increased risk of symptomatic RKOA in the OAI and MOST. Light work may be associated with a decreased risk of incident TKR and disease progression.

CONCLUSION

Heavy manual work carries an increased risk of incident knee OA; particularly among men. Workload may influence the occurrence of TKR and disease progression.

The Arthroplasty Candidacy Help Engine tool to select candidates for hip and knee replacement surgery: development and economic modelling

BACKGROUND

There is no good evidence to support the use of patient-reported outcome measures (PROMs) in setting preoperative thresholds for referral for hip and knee replacement surgery. Despite this, the practice is widespread in the NHS.

OBJECTIVES/RESEARCH QUESTIONS

Can clinical outcome tools be used to set thresholds for hip or knee replacement? What is the relationship between the choice of threshold and the cost-effectiveness of surgery?

METHODS

A systematic review identified PROMs used to assess patients undergoing hip/knee replacement. Their measurement properties were compared and supplemented by analysis of existing data sets. For each candidate score, we calculated the absolute threshold (a preoperative level above which there is no potential for improvement) and relative thresholds (preoperative levels above which individuals are less likely to improve than others). Owing to their measurement properties and the availability of data from their current widespread use in the NHS, the Oxford Knee Score (OKS) and Oxford Hip Score (OHS) were selected as the most appropriate scores to use in developing the Arthroplasty Candidacy Help Engine (ACHE) tool. The change in score and the probability of an improvement were then calculated and modelled using preoperative and postoperative OKS/OHSs and PROM scores, thereby creating the ACHE tool. Markov models were used to assess the cost-effectiveness of total hip/knee arthroplasty in the NHS for different preoperative values of OKS/OHSs over a 10-year period. The threshold values were used to model how the ACHE tool may change the number of referrals in a single UK musculoskeletal hub. A user group was established that included patients, members of the public and health-care representatives, to provide stakeholder feedback throughout the research process.

RESULTS

From a shortlist of four scores, the OHS and OKS were selected for the ACHE tool based on their measurement properties, calculated preoperative thresholds and cost-effectiveness data. The absolute threshold was 40 for the OHS and 41 for the OKS using the preferred improvement criterion. A range of relative thresholds were calculated based on the relationship between a patient's preoperative score and their probability of improving after surgery. For example, a preoperative OHS of 35 or an OKS of 30 translates to a 75% probability of achieving a good outcome from surgical intervention. The economic evaluation demonstrated that hip and knee arthroplasty cost of < £20,000 per quality-adjusted life-year for patients with any preoperative score below the absolute thresholds (40 for the OHS and 41 for the OKS). Arthroplasty was most cost-effective for patients with lower preoperative scores.

LIMITATIONS

The ACHE tool supports but does not replace the shared decision-making process required before an individual decides whether or not to undergo surgery.

CONCLUSION

The OHS and OKS can be used in the ACHE tool to assess an individual patient's suitability for hip/knee replacement surgery. The system enables evidence-based and informed threshold setting in accordance with local resources and policies. At a population level, both hip and knee arthroplasty are highly cost-effective right up to the absolute threshold for intervention. Our stakeholder user group felt that the ACHE tool was a useful evidence-based clinical tool to aid referrals and that it should be trialled in NHS clinical practice to establish its feasibility.

FUTURE WORK

Future work could include (1) a real-world study of the ACHE tool to determine its acceptability to patients and general practitioners and (2) a study of the role of the ACHE tool in supporting referral decisions.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Contact kinematics of patient-specific instrumentation versus conventional instrumentation for total knee arthroplasty

BACKGROUND

The goal was to evaluate the joint contact kinematics of total knee arthroplasties implanted using patient-specific instrumentation (PSI) compared to conventional instrumentation (CI). We hypothesized that use of PSI would not significantly alter contact kinematics.

METHODS

The study was a prospective randomized controlled trial, with equal allocation of fifty patients to PSI and CI groups. At two years post-operation, patients underwent weight-bearing stereo X-ray examinations at 0°, 20°, 40°, 60°, 80°, and 100° of flexion. The shortest tibiofemoral distance on each condyle determined the contact location. Magnitude of the shortest distance was measured and condylar separation was analyzed using thresholds of 0.5 and 0.75 mm. Kinematic measurements derived from the shortest distance included anteroposterior (AP) translation, excursion, axial rotation, and paradoxical anterior motion. Pivot position and cam/post contact were also investigated.

RESULTS

There were no differences (p > 0.05) in medial and lateral AP contact locations, excursions, and magnitude of anterior motion, or in axial rotation, pivot patterns, frequency of cam/post engagement, frequency of medial anterior motion, and condylar separation at a 0.75 mm threshold. Significant differences were found in frequency of lateral anterior motion (p = 0.048) and condylar separation at a 0.5 mm threshold (p = 0.010). Both groups displayed typical kinematics for a fixed-bearing posterior-stabilized implant.

CONCLUSIONS

We found no major differences in knee kinematics between PSI and CI groups, which suggest that PSI does not provide a significant kinematic advantage over conventional instruments.

Pain, sensitization and physical performances in patients with chronic painful knee osteoarthritis or chronic pain following total knee arthroplasty: An explorative study

BACKGROUND

The aim of this study was to assess clinical pain, pain sensitization and physical performances to profile patients with chronic painful knee osteoarthritis (OA) or pain after total knee arthroplasty (TKA). Examining the interactions between pain mechanisms and physical performances would enable us to investigate the underlying explanatory relationships between these parameters.

METHODS

In this explorative study, 70 patients with chronic painful knee OA (N = 46) or chronic pain after TKA (N = 24) were assessed for clinical pain, quantitative sensory profiling (mechanical pinprick pain sensitivity, temporal summation (TS) and conditioned pain modulation), physical performances (chair stand, walk and stair climb tests) and self-reported outcomes. Between-group comparisons were made using ANCOVA tests and associations between outcomes were analysed using multivariate linear regression models.

RESULTS

Overall, no differences between groups regarding clinical pain and quantitative sensory profiling outcomes were observed. Physical performances were lower in the TKA group compared with the OA group with moderate-to-large effect sizes, and a tendency towards better scores in self-reported outcomes for the OA group was observed with small-to-moderate effect sizes. Self-reported function seems to be associated with physical performances in the TKA group. Sensitization (TS) appears to be associated with poorer physical performances in the OA group.

CONCLUSIONS

Similar profiles for pain intensity, signs of sensitization and conditioned pain modulation were observed. Patients with TKA seems to have impaired physical performances compared with the OA group, underlining the importance of targeting physical performances. Only the OA patients showed an association between sensitization (TS) and physical performance.

SIGNIFICANCE

Quantitative pain profiling assessment was used to assess pain intensities and pain mechanisms. We observed associations between physical performances and temporal summation in the OA group underlining the importance of assessing motor functions and pain mechanisms in the same trial. We observed lower levels of physical performances in the TKA group compared with the OA group, suggesting that examination and rehabilitation of physical performances is essential for TKA patients with chronic pain.

The relationship between alignment, function and loading in total knee replacement: In-vivo analysis of a unique patient population

The purpose of this study was to quantify the effect of total knee replacement (TKR) alignment on in-vivo knee function and loading in a unique patient cohort who have been identified as having a high rate of component mal-alignment. Post-TKR (82.4 ± 6.7 months), gait analysis was performed on 25 patients (27 knees), to calculate knee kinematics and kinetics. For a step activity, video fluoroscopic analysis quantified in-vivo implant kinematics. Frontal plane lower-limb alignment was defined by the Hip-Knee-Ankle angle (HKA) measured on long leg static X-rays. Transverse plane component rotation was calculated from computed tomography scans. Sagittal plane alignment was defined by measuring the flexion angle of the femoral component and the posterior tibial slope angle (PTSA). For gait analysis, a more varus HKA correlated with increased peak and dynamic joint kinetics, predicting 47.6% of Knee Adduction Angular Impulse variance. For the step activity, during step-up and single leg loaded, higher PTSA correlated with a posterior shift in medial compartment Anterior-Posterior (AP) translation. During step-down, higher PTSA correlated with reduced lateral compartment AP translation with a posterior shift in AP translation in both compartments. A more varus HKA correlated with a more posterior medial AP translation and inter-component rotation was related to transverse plan range of motion. This in-vivo study found that frontal plane lower-limb alignment had a significant effect on joint forces during gait but had minimal influence on in-vivo implant kinematics for step activity. PTSA was found to influence in-vivo TKR translations and is therefore an important surgical factor.

Predictors of chronic pain and level of physical function in total knee arthroplasty: a protocol for a systematic review and meta-analysis

INTRODUCTION

One in five patients undergoing total knee arthroplasty (TKA) experience unchanged or worse pain and physical function 1 year after surgery. Identifying risk factors for unfavourable outcomes is necessary to develop tailored interventions to minimise risk. There is a need to review more current literature with updated methodology that addresses the limitations of earlier systematic reviews and meta-analyses. We present a Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols compliant protocol for a systematic review and meta-analysis of predictors of chronic pain and impaired function after TKA.

METHODS AND ANALYSIS

This review will include prospective longitudinal observational studies, or randomised trials (including cluster and crossover designs) that report arm-wise predictors of chronic postsurgical pain or impaired physical function at 3 months, 6 months or 12 months. A comprehensive literature search of studies published between 2000 and 2019 will be performed in Medline, Embase, CINAHL, Cochrane Library and PEDro. Blinded assessment with consensus agreement will be applied for inclusion of studies, data extraction and assessment of bias risk (Quality in Prognosis Studies tool). The co-primary outcomes, pain and impaired function, at 12 months after TKA will be analysed separately. Estimates of association between each outcome and any preoperative or intraoperative factor that may predict chronic pain or impaired physical function will be extracted from the included studies, where possible. For randomised studies, results will only be extracted from TKA arms (or the first period of crossover trials). Estimates of association from the primary evidence will be synthesised narratively, and quantitatively using multivariate meta-analysis to provide 'pooled' estimates of association. Subgroup and sensitivity analyses will be performed. Certainty of evidence for each predictor will be derived from the Grading of Recommendations Assessment, Development and Evaluation framework.

ETHICS AND DISSEMINATION

No ethical issues are associated with this project. The results from this review will be published in peer-reviewed journals and presented at international conferences.

PROSPERO REGISTRATION NUMBER

CRD42018079069.

Narcotic Consumption in Opioid-Naïve Patients Undergoing Total Hip and Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is associated with increased risk of prolonged narcotic requirement compared to total hip arthroplasty (THA). This study aims to compare acute postoperative narcotic consumption between the 2 procedures and quantify amount of narcotics used by opioid prescribed.

METHODS

From October 2017 to August 2019, patients were surveyed at 4-week follow-up to determine amount and duration of opioids used and whether they continued to require narcotics. Among 1332 patients who self-identified as opioid naïve, 670 underwent THA and 662 underwent TKA. Descriptive analysis was performed based on data type.

RESULTS

The total morphine equivalent dose (MED) used in the postoperative period was lower in THA than in TKA (143 ± 160 vs 259 ± 250 MED, P < .001). The duration of use was shorter, total amount of pills consumed was lower, and refill rates were less in THA compared to TKA regardless of which opioid was prescribed. A smaller proportion of patients required narcotics at 4-week follow-up in THA compared to TKA. A postoperative prescription of 45 pills of any one type of narcotic was sufficient for nearly 90% of THA patients, and 60 pills of any one type of narcotic was appropriate for over 75% of TKA patients.

CONCLUSION

THA is associated with less total narcotic consumption, shorter duration of use, less refills, and lower likelihood of requiring narcotics at 4-week follow-up. Percentiles of total narcotics consumed are provided to promote judicious postoperative prescribing patterns, and one could consider further reducing narcotics when utilizing our protocol, particularly for THA patients.

LEVEL OF EVIDENCE

This is a level III retrospective cohort study reviewing narcotic use in over 900 consecutive opioid-naïve patients undergoing total hip and knee arthroplasty.

Unicompartmental knee arthroplasty undertaken using a fast-track protocol

Aims

The aim of this prospective multicentre study was to describe trends in length of stay and early complications and readmissions following unicompartmental knee arthroplasty (UKA) performed at eight different centres in Denmark using a fast-track protocol and to compare the length of stay between centres with high and low utilization of UKA.

Methods

We included data from eight dedicated fast-track centres, all reporting UKAs to the same database, between 2010 and 2018. Complete ( > 99%) data on length of stay, 90-day readmission, and mortality were obtained during the study period. Specific reasons for a length of stay of > two days, length of stay > four days, and 30- and 90-day readmission were recorded. The use of UKA in the different centres was dichotomized into ≥ 20% versus < 20% of arthroplasties which were undertaken being UKAs, and ≥ 52 UKAs versus < 52 UKAs being undertaken annually.

Results

A total of 3,927 procedures were included. Length of stay (mean 1.1 days (SD 1.1), median 1 (IQR 0 to 1)) was unchanged during the study period. The proportion of procedures with a length of stay > two days was also largely unchanged during this time. The percentage of patients discharged on the day of surgery varied greatly between centres (0% to 50% (0 to 481)), with centres with high UKA utilization (both usage and volume) having a larger proportion of same-day discharges. The 30- and 90-day readmissions were 166 (4.2%) and 272 (6.9%), respectively; the 90-day mortality was 0.08% (n = 3).

Conclusion

Our findings suggest general underutilization of the potential for quicker recovery following UKA in a fast-track setup. Cite this article: Bone Joint J 2020;102-B(9):1167–1175.

Are There Differences in Micromotion on Radiostereometric Analysis Between Bicruciate and Cruciate-retaining Designs in TKA? A Randomized Controlled Trial

BACKGROUND

Bicruciate-retaining TKA has been proposed to improve clinical outcomes by maintaining intrinsic ACL function. However, because the unique design of the bicruciate-retaining tibial component precludes a tibial stem, fixation may be compromised. A radiostereometric analysis permits an evaluation of early migration of tibial components in this setting, but to our knowledge, no such analysis has been performed.

QUESTIONS/PURPOSES

We performed a randomized controlled trial using a radiostereometric analysis and asked, at 2 years: (1) Is there a difference in tibial implant migration between the bicruciate-retaining and cruciate-retaining TKA designs? In a secondary analysis, we asked: (2) Is there a difference in patient-reported outcomes (Oxford Knee Score [OKS] and Forgotten Joint Score [FJS] between the bicruciate-retaining and cruciate-retaining TKA designs? (3) What is the frequency of reoperations and revisions for the bicruciate-retaining and cruciate-retaining TKA designs?

METHODS

This parallel-group trial (ClinicalTrials.gov: NCT01966848) randomized 50 patients with an intact ACL who were eligible to undergo TKA to receive either a bicruciate-retaining or cruciate-retaining TKA. Patients were blinded to treatment allocation. The primary outcome was the maximum total point motion (MTPM) of the tibial component measured with model-based radiostereometric analysis (RSA) at 2 years postoperatively. The MTPM is a translation vector defined as the point in the RSA model that has the greatest combined translation in x-, y- and z-directions. A 1-year postoperative mean MTPM value of 1.6 mm has been suggested as a threshold for unacceptable increased risk of aseptic loosening after both 5 and 10 years. The repeatability of the MTPM was found to be 0.26 mm in our study. Patient-reported outcome measures were assessed preoperatively and at 2 years postoperatively with the OKS (scale of 0-48, worst-best) and FJS (scale of 0-100, worst-best). Baseline characteristics did not differ between groups. At 2 years postoperatively, RSA images were available for 22 patients who underwent bicruciate-retaining and 23 patients who underwent cruciate-retaining TKA, while patient-reported outcome measures were available for 24 patients in each group. The study was powered to detect a 0.2-mm difference in MTPM between groups (SD = 0.2, significance level = 5%, power = 80%).

RESULTS

With the numbers available, we found no difference in MTPM between the bicruciate-retaining and cruciate-retaining groups. The median (interquartile range [IQR]) MTPM was 0.52 mm (0.35 to 1.02) and 0.42 mm (0.34 to 0.70) in the bicruciate-retaining and cruciate-retaining groups, respectively (p = 0.63). There was no difference in the magnitude of improvement in the OKS from preoperatively to 2 years postoperative between the groups (median delta [IQR] for bicruciate-retaining 18 [14 to 23] versus cruciate-retaining 18 [15 to 21], difference of medians 0; p = 0.96). Likewise, there was no difference in the magnitude of improvement in the FJS score from preoperatively to 2 years postoperative between the groups (mean ± SD for bicruciate-retaining 46 ± 32 versus cruciate-retaining 48 ± 16, mean difference, 2; p = 0.80). Three patients in the bicruciate-retaining group underwent arthroscopically assisted manipulation at 3 to 4 months postoperatively, and one patient in the bicruciate-retaining group sustained a tibial island fracture during primary surgery and underwent a revision procedure after 6 months. There were no reoperations or revisions in the cruciate-retaining group.

CONCLUSIONS

With the numbers available, we found no differences between the bicruciate-retaining and the cruciate-retaining implants in terms of stable fixation on RSA or patient-reported outcome measure scores at 2 years, and must therefore recommend against the routine clinical use of the bicruciate-retaining device. The complications we observed with the bicruciate-retaining device suggest it has an associated learning curve and the associated risks of novelty with no demonstrable benefit to the patient; it is also likely to be more expensive in most centers. Continued research on this implant should only be performed in the context of controlled trials.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Manipulation Under Anesthetic After Primary Knee Arthroplasty Is Associated With a Higher Rate of Subsequent Revision Surgery

AIM

To determine the association between manipulation under anesthetic (MUA) after primary knee arthroplasty and subsequent revision surgery.

METHODS

Patients undergoing primary knee arthroplasty from April 2011 to April 2016 with minimum 1-year follow-up to April 2017 were identified from the national hospital episode statistics for England. The first arthroplasty per patient, per side, was included; cases with a record of subsequent infection or periprosthetic fracture were excluded. Patients undergoing MUA within 1 year to the same knee were identified, defining the populations for the MUA and non-MUA cohorts. Mortality-adjusted Kaplan-Meier survival analysis (revision arthroplasty) was performed to a maximum of 6 years. A Cox proportional hazards model was used to determine the hazard for revision, adjusting for type of primary arthroplasty, gender, age group, year, comorbidity index, obesity, regional deprivation, rurality, and ethnicity.

RESULTS

A total of 309,650 primary arthroplasty cases (309,650 patients) were included. MUA within 1 year was recorded in 6882 patients (2.22%; 95% confidence interval [95% CI], 2.17-2.28) defining the MUA cohort; all others were included in the parallel non-MUA cohort. At 6 years, the mortality-adjusted estimated implant survival rate in the MUA cohort was 91.2% (95% CI, 90.0-92.2) in comparison to 98.1% (95% CI, 98.0-98.2) in the non-MUA cohort. In the fully adjusted model, this corresponded to an adjusted hazard for revision of 5.03 (hazard ratio; 95% CI, 4.55-5.57).

CONCLUSION

Patients who underwent MUA within 1 year of primary arthroplasty were at a 5-fold increased risk of subsequent revision even after excluding cases of infection or fracture. Further investigation of the etiology of stiffness after primary knee arthroplasty and the optimal treatment options to improve outcomes is justified.

Punicalagin ameliorates wear-particle-induced inflammatory bone destruction by bi-directional regulation of osteoblastic formation and osteoclastic resorption

Periprosthetic osteolysis (PPO) and subsequent aseptic loosening are the main causes of implant failure and revision surgery. Emerging evidence has suggested that wear-particle-induced chronic inflammation, osteoblast inhibition and osteoclast formation at the biointerface of implant materials are responsible for PPO. Punicalagin (PCG), a polyphenolic compound molecularly extracted from pomegranate rinds, plays a critical role in antioxidant, anticancer and anti-inflammatory activities. However, whether PCG could attenuate chronic inflammation and bone destruction at sites of titanium (Ti)-particle-induced osteolysis remains to be determined. In this study, we explored the effect of PCG on Ti-particle-induced osteolysis in vivo and osteoblast and osteoclast differentiation in vitro. We found that PCG could relieve wear-particle-induced bone destruction in a murine calvarial osteolysis model by increasing bone formation activity and suppressing bone resorption activity. PCG treatment also reduced the Ti-particle-induced inflammatory response in vivo and vitro. In addition, we also observed that PCG promotes osteogenic differentiation of MC3T3-E1 cells under inflammatory conditions and inhibits RANKL-induced osteoclast formation of bone marrow-derived macrophages (BMMs). Meanwhile, the induction of the RANKL to OPG ratio was reversed by PCG treatment in vivo and in vitro, which demonstrated that PCG could also indirectly inhibit osteoclastogenesis. Collectively, our findings suggest that PCG represents a potential approach for the treatment of wear-particle-induced inflammatory osteolysis.

Current state of total knee arthroplasty

Total knee arthroplasty (TKA) is a successful and cost-effective treatment for end-stage degenerative arthritis. The aging of society and an increase in the prevalence of obesity has led to increases in the prevalence of arthritis and the incidence of TKA. Currently, the total number of procedures in Korea per year has reached 90,000. With the rapid growth, we need to know about the current state of TKA. The purpose of this review is to summarize the recent literature regarding TKA. The main indication for TKA is end-stage arthritis with severe pain, reduced function, and no response to conservative management. Metal on the polyethylene-bearing surface and cobalt alloy are used in most TKAs. Despite good clinical outcomes and long-term survival rates after TKA in many papers, 20% of patients are dissatisfied with the outcome of surgery. To improve the patient’s satisfaction, surgeons should understand factors affecting patient’s satisfaction, including patient’s expectations, age, and preoperative mental state. Navigation-assisted surgery and robotic surgery have been introduced in knee arthroplasty to achieve more precise and accurate alignment. There is some evidence to suggest that computer-assisted surgery reduces revision rates. However, clinical efficacy is also controversial, and a long-term follow-up study is required. The common complications of TKA include infection, polyethylene wear, loosening, stiffness, periprosthetic fracture, and thromboembolism. An understanding of the potential complications and pitfalls of TKA is essential for prevention.

Sport and Physical Activity Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aims to analyze the sport habits of patients before and after primary total knee arthroplasty (TKA) by answering the following questions: (1) Is there a postoperative improvement of sport activity based on validated activity scores? (2) Does age influence the postoperative improvement of sport activity based on validated activity scores? (3) What are the preoperative and postoperative sport participation rates and the return to sport rates (RTS)? (4) What are the sport disciplines and sport patterns?

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE and Scopus were searched for studies reporting the physical activity level and sport habits of patients before and after primary TKA based on validated activity scores or an activity questionnaire. Random effect models were implemented to pool the mean differences (MDs) of activity score values and the difference between preoperative and postoperative sport participation rates.

RESULTS

Twenty-five studies were included reporting on 6035 TKAs. Physical activity levels improved significantly according to the University of California, Los Angeles (UCLA) activity score (MD 1.55, 95% confidence interval [CI] 0.35-2.76, n = 1239, I² = 99%, P < .01) and the Tegner score (MD 1.14, 95% CI -0.48 to 2.76, n = 483, I² = 93%, P < .01). Younger patients (≤55 years) had the highest improvement in the UCLA activity scores following primary TKA (MD 3.12, 95% CI -1.79 to 8.04, n = 67, I² = 96%, P < .01). Sport participation decreased slightly but not significantly (incidence rate difference -8%, 95% CI -0.14 to -0.2, n = 2673 patients, I² = 38%, P = .09). The median RTS was 71.2%. Patients predominantly engaged in low-impact sports, especially walking, cycling, and swimming.

CONCLUSION

According to validated activity scores, the level of physical activity significantly increases following primary TKA. Young patients (≤55 years) had the highest gain in physical activity according to the UCLA activity score following primary TKA. Sport participation shows a slight but nonsignificant decrease; intermediate and high-impact sports were abandoned to a large degree while participation rates for low-impact sports predominantly increased. RTS varied, although approximately 70% resume sport activities.

LEVEL OF EVIDENCE

IV (review including case series).

The diagnostic potential of low-field MRI in problematic total knee arthroplasties - a feasibility study

Purpose

Low-field MRI, allowing imaging in supine and weight-bearing position, may be utilized as a non-invasive and affordable tool to differentiate between causes of dissatisfaction after TKA (‘problematic TKA’). However, it remains unclear whether low-field MRI results in sufficient image quality with limited metal artefacts. Therefore, this feasibility study explored the diagnostic value of low-field MRI concerning pathologies associated with problematic TKA’s’ by comparing low-field MRI findings with CT and surgical findings. Secondly, differences in patellofemoral parameters between supine and weight-bearing low-field MRI were evaluated.

Methods

Eight patients with a problematic TKA were scanned using low-field MRI in weight-bearing and supine conditions. Six of these patients underwent revision surgery. Scans were analysed by a radiologist for pathologies associated with a problematic TKA. Additional patellofemoral and alignment parameters were measured by an imaging expert. MRI observations were compared to those obtained with CT, the diagnosis based on the clinical work-up, and findings during revision surgery.

Results

MRI observations of rotational malalignment, component loosening and patellofemoral arthrosis were comparable with the clinical diagnosis (six out of eight) and were confirmed during surgery (four out of six). All MRI observations were in line with CT findings (seven out of seven). Clinical diagnosis and surgical findings of collateral excessive laxity could not be confirmed with MRI (two out of eight).

Conclusion

Low-field MRI shows comparable diagnostic value as CT and might be a future low cost and ionizing radiation free alternative. Differences between supine and weight-bearing MRI did not yield clinically relevant information.

The study was approved by the Medical Research Ethics Committees of Twente (Netherlands Trial Register: Trial NL7009 (NTR7207). Registered 5 March 2018, https://www.trialregister.nl/trial/7009).

Development of a Personalized m/eHealth Algorithm for the Resumption of Activities of Daily Life Including Work and Sport after Total and Unicompartmental Knee Arthroplasty: A Multidisciplinary Delphi Study

Evidence for recommendations concerning the resumption of activities of daily life, including work and sport, after knee arthroplasty is lacking. Therefore, recommendations vary considerably between hospitals and healthcare professionals. We aimed to obtain multidisciplinary consensus for such recommendations. Using a Delphi procedure, we strived to reach consensus among a multidisciplinary expert panel of six orthopaedic surgeons, three physical therapists, five occupational physicians and one physician assistant on recommendations regarding the resumption of 27 activities of daily life. The Delphi procedure involved three online questionnaire rounds and one face-to-face consensus meeting. In each of these four rounds, experts independently decided at what time daily life activities could feasibly and safely be resumed after knee arthroplasty. We distinguished patients with a fast, average and slow recovery. After four Delphi rounds, the expert panel reached consensus for all 27 activities. For example, experts agreed that total knee arthroplasty patients with a fast recovery could resume cycling six weeks after the surgery, while those with an average and slow recovery could resume this activity after nine and twelve weeks, respectively. The consensus recommendations will subsequently be integrated into an algorithm of a personalized m/eHealth portal to enhance recovery among knee arthroplasty patients.

Quality of life outcomes in patients undergoing knee replacement surgery: longitudinal findings from the QPro-Gin study

Background

Many patients report postoperative pain, limited improvement in physical function and poor quality of life (QOL) after knee replacement surgery. Our study uses baseline predictors of change to investigate the QOL of patients with knee osteoarthritis 3-months after knee replacement surgery.

Methods

A prospective observational study was designed to evaluate patients (n = 132) scheduled for uni-compartmental or total knee replacement surgery who were assessed at baseline (preoperatively) and 3-months after. Physical and mental endpoints based on the component scores of the SF-12 and on the Western Ontario and McMaster Universities Arthritis (WOMAC) index were used to investigate patients’ QOL. Generalised estimating equation methodology was used to assess patients’ baseline characteristics (age, sex, education, body mass index (BMI), comorbidity, depressive symptoms, cognitive impairment, smoking/alcohol and type of surgery), the study endpoints and their changes over a 3-month post-surgery period. Stratified analyses by rehabilitation status after discharge were performed.

Results

Longitudinal data analysis showed that the baseline factors associated with improvement in general QOL at the 3-month post-surgery assessment were higher BMI, a high comorbidity, total (as opposed to unicompartmental) knee replacement and low education level. Data analysis of the patients who underwent rehabilitation after discharge revealed that the current smokers’ physical QOL worsened over time. The general QOL was unchanged over time in the presence of depressive symptomatology.

Conclusions

These findings underline the importance of using comprehensive assessment methods to identify factors affecting functionality and QOL, and developing interventions to improve the health/wellbeing of patients after knee replacement.

Bactericidal coating to prevent early and delayed implant-related infections

The occurrence of an implant-associated infection (IAI) with the formation of a persisting bacterial biofilm remains a major risk following orthopedic biomaterial implantation. Yet, progress in the fabrication of tunable and durable implant coatings with sufficient bactericidal activity to prevent IAI has been limited. Here, an electrospun composite coating was optimized for the combinatorial and sustained delivery of antibiotics. Antibiotics-laden poly(ε-caprolactone) (PCL) and poly`1q`(lactic-co glycolic acid) (PLGA) nanofibers were electrospun onto lattice structured titanium (Ti) implants. In order to achieve tunable and independent delivery of vancomycin (Van) and rifampicin (Rif), we investigated the influence of the specific drug-polymer interaction and the nanofiber coating composition on the drug release profile and durability of the polymer-Ti interface. We found that a bi-layered nanofiber structure, produced by electrospinning of an inner layer of [PCL/Van] and an outer layer of [PLGA/Rif], yielded the optimal combinatorial drug release profile. This resulted in markedly enhanced bactericidal activity against planktonic and adherent Staphylococcus aureus for 6 weeks as compared to single drug delivery. Moreover, after 6 weeks, synergistic bacterial killing was observed as a result of sustained Van and Rif release. The application of a nanofiber-filled lattice structure successfully prevented the delamination of the multi-layer coating after press-fit cadaveric bone implantation. This new lattice design, in conjunction with the multi-layer nanofiber structure, can be applied to develop tunable and durable coatings for various metallic implantable devices. This is particularly appealing to tune the release of multiple antimicrobial agents over a period of weeks to prevent early and delayed onset IAI.

[Alignment techniques for implantation of a total knee endoprosthesis with particular focus on kinematic alignment]

BACKGROUND

This review introduces various techniques for implantation of a total knee endoprosthesis and scrutinizes the "mechanical alignment" of a total knee endoprosthesis, whereby the various alignment concepts are examined. In particular, kinematic alignment, in terms of its significance, the individual steps of the implantation technique and the data collected, will be examined in more detail.

METHODS

Improvement in the clinical results after implantation of a total knee endoprosthesis can be achieved by a personalized, individualized, physiological implantation that respects the unique anatomical characteristics of each patient. In recent years, many alternative alignment techniques have been developed, some of them showing promising approaches.

RESULTS

The kinematic implantation technique can be performed reliably and inexpensively, and shows good biomechanical results. Although the first clinical results are encouraging, further studies should be carried out to determine the limits of optimal alignment.