Knee replacement

Changing the narrative for exercise-based prehabilitation: Evidence-informed and shared decision making when discussing the need for a total knee arthroplasty with patients

Objective

To examine a novel application of exercise-based prehabilitation in severe knee osteoarthritis-termed "pre-evaluation exercise"-focused on supporting surgical decision-making and adherence to clinical guidelines, rather than attempting to enhance post-operative recovery.

Design

This narrative review discusses the usage of exercise in the clinical decision process for total knee arthroplasty (TKA). It synthesizes data from studies on exercise-based prehabilitation, covering patient selection, implementation, and its effects on surgical choices. Emphasis is placed on multi-disciplinary coordination within an Enhanced Recovery After Surgery (ERAS) framework.

Results

Evidence suggests that pre-evaluation exercise can improve symptom management and may lead to delayed or reduced surgical intervention. This approach shows significant potential in reducing the rate of TKA surgeries among patients with severe knee osteoarthritis by improving physical conditioning, addressing symptom variability, and enhancing informed, patient-centered surgical decisions.

Conclusions

Pre-evaluation exercise in knee osteoarthritis is a viable strategy that complements existing ERAS initiatives by facilitating guideline-conformant surgical decision-making. Incorporating this into pre-surgical care pathways can foster improved patient-related outcomes and healthcare resource optimization.

Adductor canal block in total knee arthroplasty: a scoping review of the literature

Background

An adductor canal block is commonly used to reduce pain after total knee arthroplasty. Practice varies in terms of site of injection, local anaesthetic, and adjuncts used, with poor consensus in relation to the best approach. The aim of this scoping review was to assess the evidence for efficacy and safety of adductor canal block, determine variation in the technique used, type and dose of medication, and compare the efficacy of adductor canal block with other nerve block techniques.

Methods

Four databases were searched to identify relevant studies (Medline, Embase, Cochrane, and ClinicalTrials.gov). A total of 285 articles were found, and data was extracted from 130 randomised controlled trials.

Results

Adductor canal block is a safe and potentially effective peripheral nerve block for reducing postoperative pain after total knee arthroplasty while preserving motor function. Of all adjuncts to adductor canal block assessed, either dexamethasone or dexmedetomidine provide additional analgesic benefit. Adductor canal block combined with peri-articular local anaesthetic injection provides the best outcomes. Continuous infusion of local anaesthetic through a catheter placed in the adductor canal provides no additional benefit over a single injection. The site of injection used for adductor canal block does not seem to affect efficacy. There was no evidence to support the superiority of any single local anaesthetic agent.

Conclusion

This scoping review has identified variation in the use of medications, doses, techniques, and adjuncts for adductor canal block. As such, definitive conclusions regarding the most effective practice for adductor canal block cannot be made.

Tranexamic Dosing for Major Joint Arthroplasty in Adult Patients with Chronic Kidney Disease: A Pharmacokinetic Study and New Dosing Regimen

BACKGROUND

Tranexamic acid is an antifibrinolytic agent routinely used during hip and knee joint replacement surgery to minimize bleeding. Chronic kidney disease is a common chronic health problem seen among adults requiring major arthroplasty surgery. Tranexamic acid is renally cleared and may accumulate in chronic kidney disease. Optimal tranexamic acid dosing and dose adjustment for chronic kidney disease patients needing major arthroplasty is unknown. The objective of this study was to serially measure plasma tranexamic acid concentrations in patients with varied kidney function undergoing hip or knee replacement surgery for population pharmacokinetic modeling and to guide new dosing recommendations.

METHODS

A prospective cohort study enrolled 21 adults undergoing hip or knee replacement surgery between June 2020 and September 2022. Based on estimated glomerular filtration rate, the patients were stratified into good (greater than or equal to 60 ml · min -1 · 1.73 m -2 ) and poor (less than 60 ml · min -1 · 1.73 m -2 ) renal function. Serial blood samples were taken to measure plasma tranexamic acid concentration levels (primary outcome) after an intravenous tranexamic acid 20-mg/kg bolus dose after anesthesia induction. Secondary clinical outcomes included adverse events (thromboembolic events, seizures), red cell transfusion, mortality, and length of hospital stay. Analyses used curve stripping and population pharmacokinetic modeling and simulation.

RESULTS

Plasma tranexamic acid concentration levels were higher in patients with poor renal function and clearance compared to those with good renal function. Population pharmacokinetic modeling tested various tranexamic acid bolus and maintenance infusion regimens. Simulations revealed that single-bolus tranexamic acid administration leads to rapid rise and decline in plasma concentrations. This study identified that plasma tranexamic acid levels of 50 to 75 mg/l were maintained for approximately 4 h using a tranexamic acid bolus infusion of 15 mg/kg over a 15-min duration together with a maintenance infusion of 7.5 or 5 mg · kg -1 · h -1 for 2 h for the good and poor renal function groups, respectively. There was no difference in secondary outcomes.

CONCLUSIONS

Population pharmacokinetic modeling and simulation resulted in recommendations for a new dosing regimen to optimize the antifibrinolytic effect of tranexamic acid and avoid excessive dosing.

Outcomes of patellofemoral joint arthroplasty compared with total knee arthroplasty for osteoarthritis : a population-based cohort study using data from the National Joint Registry and Hospital Episode Statistics for England

Aims

The surgical options for patients with osteoarthritis (OA) of the patellofemoral joint (PFJ) involve a patellofemoral joint arthroplasty (PFA) or a total knee arthroplasy (TKA). The aim of this study was to describe and compare the safety profile and risk of revision of these two procedures.

Methods

The records of patients from the UK National Joint Registry who underwent PFA or TKA between April 2003 and December 2021 were linked to the Hospital Episode Statistics database. Using Poisson regression, a 30-day safety profile was created by plotting risk ratios, absolute risk, and the differences in risk of myocardial infarction, respiratory tract infection, urinary tract infection (UTI), stroke, delirium, deep vein thrombosis/pulmonary embolism (DVT/PE), wound infection, and death. A parametric survival model was used to model the survival of a PFA compared with a TKA over the course of the postoperative time period. Differences in hazard ratios were plotted by sex for PFA. Confounding was handled by inverse proportional treatment weighting. The indications for revision and the length of stay in hospital were compared between the procedures.

Results

A total of 7,819 PFAs and 662,141 TKAs were analyzed. Patients who underwnt PFA were significantly less likely to have complications than those who underwent TKA: respiratory tract infection (risk ratio (RR) 0.65 (95% CI 0.47 to 0.90); p = 0.011), DVT/PE (RR 0.35 (95% CI 0.24 to 0.52); p < 0.001), UTI (RR 0.59 (95% CI 0.40 to 0.88); p = 0.001), wound infection (RR 0.73 (95% CI 0.57 to 0.91); p = 0.006), and death within 30 days postoperatively (RR 0.36 (95% CI 0.14 to 0.98); p = 0.045). Over ten years, PFAs had an 85% survival (95% CI 0.84 to 0.86) and TKAs had a 95% survival (95% CI 0.95 to 0.96). Within two years, the indication for revision of a PFA was most likely to be pain, while infection was the most common indication for revision of a TKA at this time.

Conclusion

PFA may be a safer procedure than TKA, being less likely to have complications, with a reduced length of stay. Despite an increased risk of revision, patients should still be counselled about the advantages of undergoing a PFA.

Wear patterns of compartments in varus knee osteoarthritis among an asian population: A cross-sectional study with radiographic and intraoperative analysis

PURPOSE

Osteoarthritis (OA) of the knee significantly impairs mobility and quality of life. Knee arthroplasties have dramatically improved patient outcomes, allowing individuals to regain independence. Unicompartmental knee arthroplasty (UKA) is a surgical option for patients with isolated single-compartment disease, offering the benefits of reduced surgical time and minimized surgical risks. However, the appropriateness of UKA is often underestimated. Therefore, this study aims to determine the proportion of patients with varus knee OA who are suitable candidates for UKA.

METHODS

A prospective cross-sectional study was conducted on 207 knees undergoing knee arthroplasty surgery for varus knee OA. Pre-operative radiographs were graded using both the Kellgren-Lawrence (KL) and modified Keyes classifications. Intra-operatively, the knees were inspected, and photographs of the tibial cut were reviewed by a neutral observer. The appropriateness of UKA was determined based on these evaluations.

RESULTS

The lateral compartment was not involved in 169 (81.6%) knees. Only six (2.9%) knees had a KL grade 4 involvement of the lateral compartment. After excluding patients with isolated medial compartment OA, no radiographic evidence of lateral and patellofemoral involvement, and a grade 1 on the modified Keyes classification, we found that 79 (38.2%) patients were suitable candidates for a medial UKA. Intraoperatively, 84 (40.6%) patients had a functional ACL with no observable wear in the lateral and patellofemoral joint (PFJ) compartments.

CONCLUSION

In patients with varus knee OA, a significant proportion have wear patterns suitable for management with a UKA. Identifying these patients requires targeted examinations and specific radiographic views.

Periprosthetic Joint Infection Occurring Following a Femoral Subcutaneous Cyst: A Rare Complication Post-Total Knee Arthroplasty

Herein, we present a rare case of periprosthetic joint infection (PJI) which was triggered by an infection with a latent subcutaneous cyst on the thigh and occurred in a strange course following total knee arthroplasty (TKA). An 87-year-old female underwent right TKA followed by left TKA 5 months later. Six weeks after left TKA, a painful subcutaneous induration appeared in the left medial thigh. Magnetic resonance imaging revealed a 30∗50-mm multifocal mass. The cystic fluid was brown and cloudy, indicating an infected cyst. Oral antimicrobial therapy was initiated for 7 days. Nine weeks after the left TKA, a left calcaneal fracture occurred. Subsequently, edema of the lower extremities and pain in the left knee gradually developed. Arthrocentesis was performed twice: joint fluid Gram staining and culture examination were negative. However, at 12.5 weeks, an alpha-defensin test of the synovial fluid was positive. Therefore, PJI was diagnosed. DAIR was performed, followed by multiantibiotic therapy. The infection subsided gradually. Edema of the lower limbs was treated with oral diuretics, lymphatic massage, and compression stockings. Consequently, the lower limb edema also improved. In this case, infection of a latent subcutaneous cyst in the thigh occurred and spread around the prosthesis due to leg edema, which was associated with loss of lower limb motion due to a calcaneal fracture. The presence of a potential thigh subcutaneous cyst is a risk factor for PJI. Moreover, lower extremity edema occurs by decreasing lower extremity motion, such as after a calcaneal fracture, and it increases the risk of extending extra-articular infection to the PJI. Potential thigh subcutaneous cysts and lower extremity edema are risk factors for the development of PJI. Orthopedic surgeons need to be aware of these facts during follow-up after TKA.

Criteria for knee flexion range of motion and quadriceps strength to ascend and descend stairs 1 year after bilateral total knee arthroplasty: A cross-sectional study

BackgroundStair ascent/descent pose significant challenges after total knee arthroplasty (TKA); however, the exact knee flexion range of motion (ROM) and quadriceps strength requirements remain unclear.ObjectiveTo establish criteria for knee flexion ROM and quadriceps strength to determine independence in stair ascent/descent and evaluate the accuracy of the combination of these factors in patients with bilateral TKA.MethodsPatients with bilateral TKA were cross-sectionally assessed at 1 year postoperatively for independence in stair ascent/descent. Receiver operating characteristic curves provided cutoff values for knee flexion ROM and quadriceps strength. The area under the curves (AUC) of each factor and logistic regression models including both factors were evaluated.ResultsEighty-two participants were included. Fifty-eight participants could independently ascend and 52 could descend stairs, with equal cutoff values for both: 121° for knee flexion ROM (AUC: 0.66 and 0.67) and 1.09 Nm/kg for quadriceps strength (AUC: 0.70 and 0.73). Logistic regression models produced AUCs of 0.73 and 0.76 for ascent and descent, respectively.ConclusionsA quadriceps strength of 1.09 Nm/kg is a useful cutoff for independent stair ascent/descent, but combining it with knee flexion ROM did not enhance accuracy. Other functions such as coordination of the knee or other joints may influence stair performance post-TKA.

Significant hindlimb static weight-bearing asymmetry persists for 40-weeks in a longitudinal study in two widely used rat models of surgically induced osteoarthritis knee pain

Introduction

Unrelenting osteoarthritis (OA) knee pain is the primary reason patients seek treatment that may ultimately result in knee replacement surgery. Although the anterior cruciate ligament transection (ACLT) and the ACLT plus medial meniscectomy (MMx) induced rat models of OA knee pain are well-characterized histologically, reports on changes in pain-like behaviors that persist longterm, are scant and so this is a knowledge gap.

Methods

We conducted a 40-week longitudinal study using these models in male Sprague-Dawley rats. Hindlimb static weight-bearing asymmetry was assessed using the incapacitance test. Von Frey filaments and an Analgesy-Meter were used to measure paw withdrawal thresholds (PWTs) and paw pressure thresholds (PPTs) respectively in the hindpaws.

Results and discussion

Our findings show significant, reproducible and long-lasting static weight-bearing asymmetry in the hindlimbs of both models (but not the sham-control group) for the 40-week study duration. Significant mechanical hypersensitivity developed in the ipsilateral hindpaws of the ACLT + MMx model (PWTs ≤8 g) which reversed spontaneously by ∼8-12-weeks. In the ACLT and the sham-groups, significant mechanical hypersensitivity did not develop in the ipsilateral hindpaws. In conclusion, hindlimb static weight-bearing asymmetry is a long-lasting, significant pain behavioral endpoint in these models suitable for assessing novel disease-modifying OA therapeutics and/or analgesic drug candidates aimed at alleviating unrelenting chronic OA knee pain in patients.

Knee and hip osteoarthritis increase the risk of cardiovascular disease: A national registry-based longitudinal cohort study

OBJECTIVE

Osteoarthritis and cardiovascular disease are major public health challenges. We aimed to estimate the average sex-specific effects of knee and hip osteoarthritis on the risk of cardiovascular disease.

METHODS

We used 2001-2015 Danish national health registry data to identify all adults with knee or hip osteoarthritis and an age-, sex-, and education-matched group without osteoarthritis. Cardiovascular disease outcomes were identified with relevant ICD-10 codes. The effects of osteoarthritis were estimated with sex-stratified multivariable Cox regression models, accounting for multiple sources of confounding determined a priori with a directed acyclic graph. Results were reported with cumulative incidence curves and hazard ratios (HR) conditioned on age, sex, education, and obesity diagnosis. Sensitivity analyses explored the potential impacts of bias owing to outcome misclassification and unmeasured confounding.

RESULTS

We analysed data from 1,838,434 adults, including 290,781 people with knee or hip osteoarthritis and 1,547,653 age-, sex-, and education-matched controls. Women with knee or hip osteoarthritis had a 44% increased hazard of cardiovascular disease (HR [95% CI] =  1.44 [1.43 to 1.46]), while men with knee or hip osteoarthritis had a 24% increased hazard of subsequent cardiovascular disease (HR[95% CI] =  1.24 [1.23 to 1.26]) compared to people without osteoarthritis. These results were confirmed by sensitivity analyses.

CONCLUSION

The apparent effect of osteoarthritis on cardiovascular disease was stronger in women than in men. Clinicians who care for patients with osteoarthritis should be aware of cardiovascular disease risk when selecting therapies and consider behavioural approaches to improving health-related physical activity behaviour in this population.

Exploring patients' experiences of self-management in rehabilitation following total knee arthroplasty: A qualitative study

Self-management during the rehabilitation of patients following total knee arthroplasty presents several challenges, with approximately 20% of patients failing to meet their recovery expectations due to inadequate self-management during the postoperative rehabilitation process. This study aimed to explore the experiences of patients with self-management during rehabilitation after total knee arthroplasty. Twenty-four participants who had undergone total knee arthroplasty in China participated in semi-structured interviews. Content analysis was used to analyze the interview data, revealing four themes: distress from postoperative complications, knowledge and guidance needs during the rehabilitation process, negative beliefs and attitudes, and fears and worries. The results indicated that participants' self-management during rehabilitation after surgery was hindered by postoperative complications. Additionally, the participants exhibited negative attitudes and experienced psychological issues related to self-management during rehabilitation. We recommend that future rehabilitation efforts for patients following total knee arthroplasty should emphasize enhanced guidance and supervision, while also addressing their psychological challenges.

Impact of high body mass index on functionally aligned image-based robotic total knee arthroplasty: Comparable functional outcomes but higher mechanical failures

OBJECTIVES

Increased body mass index (BMI) poses challenges in total knee arthroplasty (TKA), including higher complication rates. Functional knee positioning (FKP) with robotic assistance provides a personalized approach to optimize alignment and soft-tissue balance, but its impact on patients with increased BMI remains unclear. This retrospective comparative study aims to evaluate the influence of obesity and its severity on clinical outcomes and complications in TKA performed with an image-based robotic system-guided by FKP principles.

METHODS

This retrospective comparative study included 372 patients who underwent robotic-assisted TKA following FKP principles. Patients were stratified into two main groups based on BMI (<30 ​kg/m2; 238 patients and ≥30 ​kg/m2; 134 patients). Outcomes included Knee Society Scores (KSS), Forgotten Joint Scores (FJS), range of motion (ROM), implant positioning, and complications, evaluated at a minimum follow-up of two years.

RESULTS

Patients with increased BMI (≥30 ​kg/m2) demonstrated similar functional outcomes to patients with BMI <30 ​kg/m2 in terms of ROM, KSS, and FJS. However, the revision rate due to mechanical failures was significantly higher in the obese group (2.99% vs. 0.42%, p ​= ​0.04; hazard ratio ​= ​6.8; 95% CI, 1.09-42.31). Implant positioning was consistent across groups, except for reduced femoral external rotation in the increased BMI group (p ​= ​0.004).

CONCLUSIONS

Robotic-assisted TKA with FKP principles achieves comparable functional outcomes for obese patients at a minimum of a 2-year follow-up, demonstrating the system's ability to address anatomical and functional challenges. However, obesity remains a critical risk factor for mechanical failures.

LEVEL OF EVIDENCE

III.

Survivorship in robotic total knee arthroplasty compared with conventional total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Total knee arthroplasty (TKA) is the gold standard surgical management for end-stage knee osteoarthritis (OA). Robotic TKA (rTKA) was developed to improve bone preparation accuracy and increase reproducibility. In many settings internationally, rTKA systems have significantly higher costs for patients, and survivorship outcomes are unclear. There are several prior meta-analyses, but these focused on clinical and radiologic outcomes, and to our knowledge, none have evaluated survival. Differences in survival between semi-active or active robotic systems are also not well investigated.

STUDY DESIGN

Meta-analysis.

METHODS

A random-effects meta-analysis was conducted on comparative studies between robotic-assisted TKAs and conventional TKAs (cTKAs) in patients undergoing TKA for primary knee OA. We searched MEDLINE, Embase, Cochrane Library, and SCOPUS from inception to 19 December 2024. Outcomes assessed were the implant survival in robotic-assisted TKA compared to conventional methods in standard primary knee OA cases, with subgrouping between active and semi-active systems performed. Secondary outcomes included associated complications, post-operative pain scores, and functional outcomes.

RESULTS

A total of 20 comparative studies were included in the meta-analysis. Among them, 2,804 patients underwent cTKA, while 2,599 underwent rTKA. At two years, the pooled survivorship rate was 97.9% (95% CI: 96-99) in the conventional group and 98.3% (95% CI: 96.2-99.2) in the robotic group. There were no significant differences between the groups (P = 0.7). There were no significant differences between the robotic (semi-active) group and the conventional group (P = 0.5) on further unpaired T-Testing. Between 2 and 5 years, pooled survivorship rates in the conventional group were 96.8% (95% CI: 90.3-99) and 97.1% (95% CI: 91.3-99) in the robotic group. There were no significant differences between groups (P = 0.9). At ten years postoperatively, pooled survivorship rates in the conventional group were 96.9% (95% CI: 95-98) and 97.8% (95% CI: 96.7-98.5) in the robotic group. There were no significant differences between the groups (P = 0.3).

CONCLUSION

Conventional TKA is non-inferior to rTKA at short and long-term follow-up with regard to implant survival, complications, and postoperative pain scores, while rTKA shows subtle improvements in functional outcome measures.

TRIAL REGISTRATION

CRD42024540997.

Efficacy of multiple autologous apheresis platelet-rich plasma injections for treating knee osteoarthritis and its influencing factors: a retrospective cohort study

BACKGROUND

The lack of standardized Platelet-Rich Plasma (PRP) protocols for Knee Osteoarthritis (KOA), combined with significant patient variability, leads to inconsistent PRP effectiveness across studies. This study aims to assess the influence of PRP injection frequencies on KOA treatment and explore the role of patient characteristics and PRP properties in the treatment's effectiveness.

METHODS

A retrospective cohort study was conducted with KOA patients who received three PRP injections (4-week intervals) at a hospital in Chongqing. The Wilcoxon signed-rank test was used to analyze differences in self-reported recovery rates across different treatment time points, with Bonferroni correction applied for significance level adjustment (α). The Mann-Whitney U test, Kruskal-Wallis H test, Spearman correlation analysis, and restricted cubic spline models were used to assess the associations between sex, baseline Kellgren-Lawrence grade, age, PRP red blood cell (RBC) concentration, PRP white blood cell (WBC) concentration, PRP platelet concentration, the multiple of PRP platelet concentration relative to the baseline autologous level (Enrichment-PLT), and self-reported recovery rates.

RESULTS

The study included 28 KOA patients. Significant improvement in self-reported recovery rate was observed 4 weeks after the first treatment (median: 30.0%, P < 0.008) and after the second treatment (median: 45.0%, P < 0.008). However, no significant change was noted 4 weeks after the third treatment (median: 55.0%, P = 0.058), and recovery rates at 8, 12, and 24 weeks post-third treatment showed no significant differences compared to 4 weeks (all P > 0.008). Additionally, no correlations were found between sex, baseline Kellgren-Lawrence grade, age, PRP RBC concentration, PRP WBC concentration, PRP platelet concentration, or Enrichment-PLT and self-reported recovery rates.

CONCLUSION

At least two PRP injections are recommended, with effects lasting for at least 24 weeks. Factors such as sex, age, baseline Kellgren-Lawrence grade, and PRP properties (prepared by apheresis) do not significantly affect treatment outcomes.

ECM-binding properties of extracellular vesicles: advanced delivery strategies for therapeutic applications in bone and joint diseases

Extracellular vesicles (EVs) and the extracellular matrix (ECM) are essential in maintaining bone and joint health by facilitating intercellular communication, regulating tissue processes and providing structural support. EVs with a large surface area carry diverse biomolecules to steer the function of cells in their surroundings. To understand how EVs localize to specific sites, we here review the available knowledge on EV surface biomolecules and their interactions with ECM components that are crucial for regulating bone remodeling, cartilage maintenance, and immune responses, playing roles in both tissue homeostasis and pathological conditions, such as arthritis and osteoporosis. More importantly, using analyses of animal experimental data, we illustrate the effect of ECM-based biomaterials (e.g. hydrogels, decellularized matrices, and ECM-mimetic scaffolds) as carriers for EVs toward effective EV delivery in regenerative and immunomodulatory therapies in bone and joint tissue. These biomaterials enable sustained release and targeted delivery of EVs, promoting bone and cartilage regeneration. The insights of this review can be utilized to advance the development of cutting-edge therapies for skeletal tissue regeneration and disease management.

Report on Evolving Indications, Technique, and Outcomes of Novel And Surgical Procedures-NUsurface

PURPOSE OF REVIEW

Meniscectomy alters knee function and known to be associated with an increased incidence of knee arthritis. Several methods and materials have been tried to replicate the function of a meniscus. One is a polycarbonate-urethane synthetic medial meniscus implant labeled as NUsurface. It is a non-anchored implant that is meant to replace the native meniscus. This article is intended to give an overview of the NUsurface implant and the experience to date.

RECENT FINDINGS

The NUsurface implant is not intended to be a substitute for arthroplasty but has indications similar to meniscal allografts. It has had both prospective double armed and single armed prospective studies. Follow up at the 2-year mark has shown the implant can be successful in decreasing patients' pain and improving function. However, the reoperation rate has been high with a little over a 1/3 requiring an additional procedure and 30% requiring implant exchanged. With improved surgical technique and knowledge of contributing anatomic variables, the reoperation rate has been decreased by half. The synthetic medial meniscus implant NUsurface is able to improve the quality of life in select patients that are symptomatic after meniscectomy. The reoperation rate is of concern but it is decreasing as we refine the variables contributing to the high rate.

The customized prosthesis for lateral unicompartmental knee arthroplasty in the treatment of malunion of a Hoffa fracture of the distal femur: A case report

INTRODUCTION

Postoperative malunion following distal femoral Hoffa fractures is rare yet challenging. We present a novel approach using customized lateral unicompartmental knee arthroplasty (UKA) to address malunion with traumatic osteoarthritis, emphasizing functional restoration.

CASE PRESENTATION

A 52-year-old male presented with persistent right knee pain (VAS score: 7/10), restricted range of motion (ROM: 0°-60° flexion), and gait instability two years after open reduction and internal fixation (ORIF) of a lateral Hoffa fracture. Imaging confirmed malunion of the fracture with traumatic osteoarthritis. A customized lateral femoral condyle prosthesis was designed using three-dimensional Computed Tomography (CT) reconstruction and implanted via a lateral parapatellar approach. Postoperative imaging (8-12 weeks) revealed optimal alignment and resolved fracture gaps. At 12 weeks, pain resolved (VAS: 1/10), ROM improved to 0°-125°, and Knee Society Score reached 85/100, with no complications.

CLINICAL DISCUSSION

Malunion after Hoffa fracture fixation is uncommon. Traditional revision ORIF may fail due to bone loss, while UKA preserves healthy compartments by restoring biomechanics. Customized implants address anatomical complexity, though long-term efficacy requires further study.

CONCLUSION

Customized UKA offers a viable solution for Hoffa fracture malunion with traumatic osteoarthritis, prioritizing joint preservation. This approach highlights the potential of patient-specific implants in complex orthopaedic salvage.

Critical Illness, Major Surgery, and Other Hospitalizations and Active and Disabled Life Expectancy

Importance

Estimates of active and disabled life expectancy, defined as the projected number of remaining years without and with disability in essential activities of daily living, are commonly used by policymakers to forecast the functional well-being of older persons.

Objective

To determine how estimates of active and disabled life expectancy differ based on exposure to intervening illnesses and injuries (or events).

Design, Setting, and Participants

This prospective cohort study was conducted in south-central Connecticut from March 1998 to December 2021 among 754 community-living persons aged 70 years or older who were not disabled. Data were analyzed from January 25 to September 18, 2024.

Exposures

Exposure to intervening events, which included critical illness, major elective and nonelective surgical procedures, and hospitalization for other reasons, was assessed each month.

Main Outcomes and Measures

Disability in 4 essential activities of daily living (bathing, dressing, walking, and transferring) was ascertained each month. Active and disabled life expectancy were estimated using multistate life tables under a discrete-time Markov process assumption.

Results

The study included 754 community-living older persons who were not disabled (mean [SD] age, 78.4 [5.3] years; 487 female [64.6%]; 67 Black [8.9%], 4 Hispanic [0.5%], 682 non-Hispanic White [90.5%], and 1 other race [0.1%]). Within 5-year age increments from 70 to 90 years, active life expectancy decreased monotonically as the number of admissions for critical illness and other hospitalization increased. For example, at age 70 years, sex-adjusted active life expectancy decreased from 14.6 years (95% CI, 13.9-15.2 years) in the absence of a critical illness admission to 11.3 years (95% CI, 10.3-12.2 years), 8.1 years (95% CI, 6.3-9.9 years), and 4.0 years (95% CI, 2.6-5.7 years) in the setting of 1, 2, or 3 or more critical illness admissions, respectively. Corresponding values for other hospitalization were 19.4 years (95% CI, 18.0-20.8 years), 13.5 years (95% CI, 12.2-14.7 years), 10.0 years (95% CI, 8.9-11.2 years), and 7.0 years (95% CI, 6.1-7.9 years), respectively. Consistent monotonic reductions were observed for sex-adjusted estimates in active life expectancy for nonelective but not elective surgical procedures as the number of admissions increased; for example, at age 70 years, estimates of active life expectancy were 13.9 years (95% CI, 13.3-14.5 years), 11.7 years (95% CI, 10.5-12.8 years), and 9.2 years (95% CI, 7.4-11.0 years) for 0, 1, and 2 or more nonelective surgical admissions, respectively; corresponding values were 13.4 years (95% CI, 12.8-3-14.1 years), 14.6 years (95% CI, 13.5-15.5 years), and 12.6 years (95% CI, 11.5-13.8 years) for elective surgical admissions. Sex-adjusted disabled life expectancy decreased as the number of admissions increased for critical illness and other hospitalization but not for nonelective or elective surgical procedures; for example, at age 70 years, disabled life expectancy decreased from 4.4 years (95% CI, 3.5-5.8 years) in the absence of other hospitalization to 3.4 years (95% CI, 2.8-4.1 years), 3.4 years (95% CI, 2.7-4.2 years), and 2.3 years (95% CI, 1.9-2.8 years) in the setting of 1, 2, or 3 or more other hospitalizations, respectively.

Conclusions and Relevance

This study found that active life expectancy among community-living older persons who were not disabled was considerably diminished in the setting of serious intervening illnesses and injuries. These findings suggest that prevention and more aggressive management of these events, together with restorative interventions, may be associated with improved functional well-being among older persons.

Early aseptic loosening and inferior patient-reported outcomes of a cementless tibial baseplate in a modern total knee arthroplasty design

Aims

This study reports the outcome of a modern total knee arthroplasty design using a cementless tibial baseplate compared to the full-cemented version.

Methods

Consecutive cohorts with 12-month follow-up were evaluated. Patients receiving a cementless tibial baseplate were compared to those who received a cemented tibial component. Endpoints included revision rates and reason for revision, patient-reported outcome measures (PROMs) using the Oxford Knee Score (OKS), and progressive radiolucency. Retrieval analysis was performed for the revised cases. Pearson correlation analysis and multiple regression analysis were used.

Results

A total of nine knees (7%) from the cementless cohort were revised, all due to aseptic loosened baseplate at a mean follow-up of 10.4 months (3 to 19), whereas the incidence of aseptic loosening of the cemented tibial baseplate was significantly lower at 0.5% (3/534; p < 0.001). The cemented cohort PROMs outperformed the cementless baseplate group at both 12 months' follow-up and the improvement from baseline (mean OKS 40.4 (SD 6.8) vs 38.5 (SD 8.1); p = 0.006; mean ΔOKS 18.8 (SD 9.0) vs 15.5 (SD 12.8); p < 0.001). There were no significant differences between the groups in the occurrence of new radiolucency at 12 months (p = 0.325). An elevated BMI was the only factor to correlate (r = -0.195) with worse values of ΔOKS (p = 0.048) in the cementless cohort. The multiple regression analysis determined that an increased BMI was the single independent predictor for aseptic loosening (p = 0.024) for the knees with a cementless tibial baseplate. Retrieval analysis suggested failed osseointegration.

Conclusion

In our cohort, there was a significantly higher incidence of aseptic loosening and worse PROMs at one year for the cementless tibial baseplate. An increased BMI may be an independent risk factor for aseptic loosening and inferior PROMs.

Single-cell RNA sequencing reveals the role of immune-related autophagy in aseptic loosening of biomaterials bone-implant

This study employed single-cell RNA sequencing (scRNA-seq) to investigate the role of immune-related autophagy in the mechanism of aseptic loosening (AL) of biomaterial bone-implant. Through single-cell analysis of AL tissues, we mapped the cellular landscape, revealing various cell types and their characteristics within the context of AL. Our study specifically targeted immune cell subpopulations, including macrophages and neutrophils. The results suggest the autophagy-related gene Ctsb was downregulated in AL, especially in macrophages. Subsequently our experiments confirmed the correlation between reduced Ctsb expression and enhanced autophagy, which may affect macrophage apoptosis and osteoblast differentiation, ultimately contributing to periprosthetic osteolysis and AL. This study offers novel perspectives into the role of immune related autophagy in the mechanism of AL and establishes a foundation for the future development of targeted therapeutic strategies for AL.

The role of the immune system in osteoarthritis: mechanisms, challenges and future directions

Osteoarthritis (OA) is a chronic joint disease that has long been considered a simple wear-and-tear condition. Over the past decade, research has revealed that various inflammatory features of OA, such as low-grade peripheral inflammation and synovitis, contribute substantially to the pathophysiology of the disease. Technological advances in the past 5 years have revealed a large diversity of innate and adaptive immune cells in the joints, particularly in the synovium and infrapatellar fat pad. Notably, the presence of synovial lymphoid structures, circulating autoantibodies and alterations in memory T cell and B cell populations have been documented in OA. These data indicate a potential contribution of self-reactivity to the disease pathogenesis, blurring the often narrow and inaccurate line between chronic inflammatory and autoimmune diseases. The diverse immune changes associated with OA pathogenesis can vary across disease phenotypes, and a better characterization of their underlying molecular endotypes will be key to stratifying patients, designing novel therapeutic approaches and ultimately ameliorating treatment allocation. Furthermore, examining both articular and systemic alterations, including changes in the gut-joint axis and microbial dysbiosis, could open up novel avenues for OA management.

One-Stage Versus Two-Stage Bilateral Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Bilateral total knee arthroplasty (B-TKA) represents an increasingly used option to address advanced bilateral knee osteoarthritis (OA). The aim of this study was to quantify and compare one-stage and two-stage B-TKA results in terms of clinical outcomes, perioperative parameters, complications, revisions, and mortality rates.

METHODS

The literature search was conducted using three databases (PubMed, Cochrane, and Web of Science) in February 2024 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis. The inclusion criteria were as follows: comparative studies, English language, with no time filter on the comparison of one-stage and two-stage B-TKA for bilateral knee osteoarthritis treatment. The quality of each article was assessed using the Cochrane risk of bias in nonrandomized studies of interventions tool.

RESULTS

Among the 2,130 articles retrieved, 69 studies (366,722 patients) were included. One-stage B-TKA showed lower rates of TKA-related complications (P = 0.043), deep infections (P < 0.001), and wound complications (P = 0.033), as well as lower operative time (P = 0.028), shorter length of hospital stay (P < 0.001), and higher improvements of Western Ontario and McMaster Universities Osteoarthritis Index score (P = 0.013) and Oxford Knee Score (P = 0.004), but higher mortality rates at the 1-month (P < 0.001), 3-month (P < 0.001), and 1-year (P = 0.001) follow-ups, as well as higher rates of neurological (P = 0.013) and gastrointestinal (P < 0.001) complications, deep vein thrombosis (P = 0.016), and pulmonary embolism (P < 0.001). The risk of bias was "low" in 26 studies, "moderate" in 36 studies, "serious" in six studies, and "critical" in one study.

CONCLUSIONS

One-stage B-TKA was associated with a higher mortality rate and thromboembolic risk while presenting lower TKA-related and infective complications compared to two-stage B-TKA. One-stage B-TKA also reduced hospital stay and total surgical time but provided only marginal improvement in clinical outcomes compared to two-stage B-TKA while showing a higher risk of neurologic and gastrointestinal complications. These results offer important information for both patients and surgeons in evaluating the most appropriate surgical approach, thereby contributing to optimize the management of patients undergoing B-TKA.

LEVEL OF EVIDENCE

Level I.

Metal Concentrations in Blood and Cerebrospinal Fluid of Patients With Arthroplasty Implants

Importance

Arthroprosthetic metal exposure has been linked to neurological dysfunction, but evidence of central nervous system exposure is largely missing.

Objective

To compare levels of all arthroplasty-relevant metals in cerebrospinal fluid (CSF), whole blood, and serum of patients with and without large joint replacement.

Design, Setting, and Participants

The NeuroWear pilot study was a single-site hospital-based cross-sectional study conducted between April 2018 and November 2019. Laboratory personnel and investigators were blinded to group allocation. Patients presenting for elective surgery under spinal anesthesia and patients scheduled for lumbar puncture at a university medical center were eligible for inclusion. Patients aged 18 years and older with at least 1 large joint replacement in situ (103 case participants) and age- and sex-matched arthroplasty-naive patients (108 control participants) were recruited. One case and 6 control participants were excluded. Each case participant was matched with 1 control participant to achieve equal self-reported sex and a minimal age difference. The data analyses were performed between May 2023 and February 2024.

Exposure

Presence of large joint replacement.

Main Outcomes and Measures

CSF, whole blood, and serum levels of aluminum, cobalt, chromium, molybdenum, nickel, niobium, tantalum, titanium, vanadium, and zirconium were quantified.

Results

A total of 204 patients (118 [58%] women and 86 [42%] men; median [range] age 69.4 [21.3-93.1] years) were included for metal analyses. In CSF, median (range) cobalt levels were significantly higher in the implant group (0.03 [0.01-0.64] μg/L) compared with the control group (0.02 [0.01-0.19] μg/L). Cobalt levels in CSF were significantly correlated with cobalt levels in serum (r = 0.72; 95% CI, 0.53-0.85) and whole blood (r = 0.82; 95% CI, 0.62-0.92). Significantly higher whole blood median (range) levels of cobalt (implant: 0.27 [0.07-24.10] μg/L; control: 0.16 [0.08-0.99] μg/L), chromium (implant: 0.47 [0.24-4.76] μg/L; control: 0.42 [0.21-1.52] μg/L), titanium (implant: 8.05 [1.14-37.20] μg/L; control: 7.15 [1.80-20.70] μg/L), niobium (implant: 0.02 [0.01-1.14] μg/L; control: 0.01 [0.01-0.11] μg/L), and zirconium (implant: 0.05 [0.01-39.90] μg/L; control: 0.03 [0.01-1.95] μg/L) were detected. Patients with an implant were found to have significantly higher median (range) CSF metal levels for titanium (implant: 0.75 [0.12-1.40] μg/L; control: 0.57 [0.13-1.10] μg/L), niobium (implant: 0.02 [0.01-0.16] μg/L; control: 0.01 [0.01-0.03] μg/L), and zirconium (implant: 0.05 [0.01-0.44] μg/L; control: 0.04 [0.01-0.28] μg/L) if those metal levels were elevated in serum. Patients with cobalt-chromium-molybdenum implant components exhibited significantly higher median (range) chromium levels in CSF than control participants (implant: 0.31 [0.02-2.05] μg/L; control: 0.23 [0.02-1.10] μg/L).

Conclusions and Relevance

In this cross-sectional study, chronic exposure to arthroplasty implants was associated with corresponding metal accumulation in blood and CSF. Arthroprosthetic cobalt, chromium, titanium, niobium, and zirconium seemed to cross neural barriers and accumulate in CSF. Correlation analyses suggested cobalt-specific transport mechanisms across neural barriers. In view of the neurotoxic effects of cobalt, subsequent studies are needed to determine whether CSF metal concentrations correlate with objective measures of neurotoxic effects and whether this may be of relevance, particularly in patients with new-onset or rapid deterioration of neurological conditions following arthroplasty.

Nutritional Interventions to Attenuate Quadriceps Muscle Deficits following Anterior Cruciate Ligament Injury and Reconstruction

Following anterior cruciate ligament (ACL) injury, quadriceps muscle atrophy persists despite rehabilitation, leading to loss of lower limb strength, osteoarthritis, poor knee joint health and reduced quality of life. However, the molecular mechanisms responsible for these deficits in hypertrophic adaptations within the quadriceps muscle following ACL injury and reconstruction are poorly understood. While resistance exercise training stimulates skeletal muscle hypertrophy, attenuation of these hypertrophic pathways can hinder rehabilitation following ACL injury and reconstruction, and ultimately lead to skeletal muscle atrophy that persists beyond ACL reconstruction, similar to disuse atrophy. Numerous studies have documented beneficial roles of nutritional support, including nutritional supplementation, in maintaining and/or increasing muscle mass. There are three main mechanisms by which nutritional supplementation may attenuate muscle atrophy and promote hypertrophy: (1) by directly affecting muscle protein synthetic machinery; (2) indirectly increasing an individual's ability to work harder; and/or (3) directly affecting satellite cell proliferation and differentiation. We propose that nutritional support may enhance rehabilitative responses to exercise training and positively impact molecular machinery underlying muscle hypertrophy. As one of the fastest growing knee injuries worldwide, a better understanding of the potential mechanisms involved in quadriceps muscle deficits following ACL injury and reconstruction, and potential benefits of nutritional support, are required to help restore quadriceps muscle mass and/or strength. This review discusses our current understanding of the molecular mechanisms involved in muscle hypertrophy and disuse atrophy, and how nutritional supplements may leverage these pathways to maximise recovery from ACL injury and reconstruction.

Development of a bespoke finite element wear algorithm to investigate the effect of femoral centre of rotation on the wear evolution in total knee replacements

Total Knee Replacements (TKRs) are a commonly used treatment to help patients suffering from severely damaged knee joints, which is normally brought on by osteoarthritis. The aim of the surgery is to reduce pain and regain function of the joint, however, some of these implants fail prematurely with implant wear being one of the main factors of failure. Computational analysis is an efficient tool that can provide an in-depth insight on the evolution of wear, before utilising experimental techniques which are time-consuming and costly. In this study, a bespoke finite element (FE) based wear algorithm has been further developed for TKRs and was used to investigate how location of femoral centre of rotation (CoR) affects the evolution of wear at the bearing surfaces. Three locations of femoral CoR have been investigated: international standards (ISO) CoR, being the location defined in ISO 14243-3, distal CoR being the centre of the femoral component's distal radius, and reference CoR being the middle ground between the two. All investigations were setup in accordance with ISO 14243-3 for displacement-controlled wear testing conditions for knee simulators. The wear algorithm extracts contact pressure and sliding distance from the FE analysis to determine wear depth, wear pattern, volumetric wear, and wear rates on the polymeric insert and femoral component's bearing surfaces using Archard's wear law. The polymeric insert volumetric wear rate after 5 million cycles (Mc) for ISO, reference, and distal CoR are 4.37mm3/Mc, 5.40mm3/Mc, and 6.83mm3/Mc respectively. Furthermore, the wear pattern's location on the bearing surfaces is dependent on the femoral CoR, with ISO CoR wear pattern being positioned more posteriorly, distal CoR being more anteriorly, and reference CoR in between ISO and distal. The ISO CoR investigation showed a region of minimal wear between two wear regions at the middle of the femoral component's wear pattern, on both medial and lateral condyles. This region of minimal wear reduces for the reference CoR and further reduces for the distal CoR. After 5 Mc, the average polymeric insert-femoral component contact area changes with femoral CoR, with the average contact area being 66.53mm2, 68.35mm2, and 71.21mm2 for ISO, reference, and distal CoRs respectively, with distal having around 7% more contact area than ISO. The results from this study show that there is a wide range of wear values for different locations of femoral CoR. As such the choice of femoral CoR should be carefully considered when performing any wear investigation to ensure that the CoR location is consistent for all studies being compared.

Risk of all-cause mortality in patients with knee osteoarthritis: A systematic review and meta-analysis of cohort studies

Objective

This systematic review and meta-analysis aimed to evaluate the risk of all-cause mortality in patients with knee osteoarthritis (OA).

Design

Comprehensive searches were conducted in PubMed, Embase, and the Cochrane Library on September 01, 2024. The review included cohort studies reporting risk estimates of all-cause mortality in knee OA patients compared to those without knee OA. Using a random-effects model, the pooled hazard ratios (HRs) were calculated. Subgroup analyses were performed according to the classification of knee OA, including radiographic knee OA only, symptomatic knee OA only, and radiographic and symptomatic knee OA.

Results

A total of 15 cohort studies involving 1,023,799 participants were included in the systematic review, with 14 studies remaining for the meta-analysis. The meta-analysis revealed that knee OA patients had an increased risk of all-cause mortality compared to those without knee OA (pooled HR: 1.21; 95% confidence interval [CI]: 1.02, 1.45). Subgroup analyses indicated the mixed results, including radiographic knee OA only (pooled HR: 1.11; 95% CI: 0.97, 1.26), symptomatic knee OA only (pooled HR: 1.07; 95% CI: 0.80, 1.43), and radiographic and symptomatic knee OA (pooled HR: 1.58; 95% CI: 1.20, 2.07).

Conclusions

This meta-analysis supports an association between knee OA and an increased risk of all-cause mortality, with a particularly pronounced risk observed in radiographic and symptomatic knee OA patients. Further research is needed to determine if OA at other sites also correlates with a higher risk of all-cause mortality.

Early radiographic evaluation of an anatomic porous tantalum tibia: A prospective, multi-center, non-randomized clinical study

BACKGROUND

Excellent survival rates have been reported for total knee arthroplasty (TKA) performed with cementless porous metal tibial components. More data, however, is necessary to assess the survival and radiographic results of modular implants with anatomic designs. The purpose of this study was to investigate the early radiographic, survival, and clinical outcomes of a cementless tantalum metal tibial implant with a modular anatomic component.

METHODS

An early follow-up of a prospective, multi-center, non-randomized outcomes study of patients who received cementless tibial implants in primary TKA between 2018 and 2020 was performed. A total of 148 implants were available for review. Radiographs, the Forgotten Joint Score (FJS-12), Oxford Knee Score (OKS), patient satisfaction, and adverse events were collected for at least two-years post-operative. A minimum of two-years follow-up was available for 119 patients and evaluated for progressive radiolucent lines (RLLs).

RESULTS

The mean follow-up was 2.2 ± 0.6 years, and the two-year implant survival rate was 98.59% (95% C.I.: 94.46, 99.64) with no aseptic revisions during the follow-up period. Progressive tibial RLLs were present in 3.4% of patients at two-years follow-up, but were all less than 2 mm with all combined RLLs less than 4 mm. The FJS-12 and OKS all significantly (p < 0.0001) increased and exceeded their respective minimal clinical important differences, and 93% of patients were satisfied at two-years follow-up.

CONCLUSION

This study supports excellent survivorship, clinical and patient reported outcomes using cementless, fixed bearing TKA with minimal complications at early follow-up. Further follow-up is necessary to confirm the sustainability of the clinical outcomes and to evaluate mid- to long-term survivorship.

Does a medial congruent bearing in total knee arthroplasty compromise fixation? A randomized controlled trial

BACKGROUND

Medially congruent (MC) bearings aim at promoting medial pivoting after total knee arthroplasty (TKA), as the congruency provides further constraint for the medial femoral compartment. However, this design difference could alter intra-articular force distribution, potentially compromising fixation of the tibia implant. The aim of this study was to compare migration, measured with radiostereometric analysis (RSA), of an MC to a more traditional cruciate retaining (CR) TKA system. Secondary aims were to compare patient-perceived treatment outcome and number of complications between the treatment groups.

METHODS

Sixty patients undergoing TKA were randomized to an MC or CR bearing and had follow up visits after 3 months, 1 and 2 years. Primary outcome was tibia implant migration, measured by maximal total point motion (MTPM) with model-based RSA, 2 years post-surgery. Secondary outcomes were tibia MTPM, change in patient-reported outcome measurements (PROMs) and number of complications registered at all follow up visits.

RESULTS

Primary outcome was available for 52 patients (27 MC patients, 25 CR patients). We found no difference in tibia MTPM between the MC and CR groups 2 years post-surgery. Median (interquartile range) MTPM was 0.60 (0.39-0.97) mm and 0.48 (0.32-0.78) mm in the MC and CR group, respectively (P = 0.167). There were no between-group differences in improvement in PROMs and no between-group differences in number of complications.

CONCLUSION

We found no compromising of tibia implant fixation in TKA by choosing an MC bearing, when compared with a CR bearing. PROMs and complication rates suggest comparable treatment results with both types of bearings in TKA.

Comparing Rates of Minimal Clinically Important Difference Between Manual and Robotic-Assisted Total Knee Arthroplasty

BACKGROUND

Differences in patient-reported outcome measures (PROMs) between manual total knee arthroplasty (mTKA) and robotic-assisted TKA (rTKA) have not been adequately assessed. We compared the minimal clinically important difference (MCID) for improvement (MCID-I) and worsening (MCID-W) between mTKA and rTKA patients.

METHODS

Patients who underwent primary TKA (874 mTKA and 439 rTKA) with complete preoperative and 1-year postoperative PROMs were retrospectively identified using a multihospital joint arthroplasty registry. Patient-Reported Outcomes Measurement Information System Physical Function Short Form 10a (PROMIS PF-10a), PROMIS Global - Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form were collected. The MCID-I, MCID-W, and "no significant change" rates were calculated using distribution-based methods. Propensity score matching was performed to control for confounding.

RESULTS

Similar 90-day pulmonary embolism (P = 0.26), deep venous thrombosis (P = 0.67), and emergency department visit (P = 0.35) rates were found. The 90-day readmission rate for mTKA was 1.7 and 3.4% for rTKA (P = 0.08), and the overall revision rates were 2.2% for mTKA and 0.7% for rTKA (P = 0.07). Revision-free survival was 99% at one and 2 years for both groups (P = 0.65 and P = 0.43, respectively). There were no differences in the proportion of patients achieving MCID-I or MCID-W for PROMIS PF-10a, PROMIS Global - Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form. The MCID-I for PROMIS PF-10a was achieved in 65.5 and 62.2% of patients who had mTKA and rTKA, respectively (P = 0.32).

CONCLUSIONS

Our study demonstrated similar complication rates and MCID-I and MCID-W attainment rates between mTKA and rTKA patients. Future studies should assess MCID attainment rates in the long term and in larger cohorts comparing mTKA and rTKA.

Characteristics of Resection Parameters in Robot-Assisted Total Knee Arthroplasty With the Ligament Balancing Workflow

OBJECTIVE

Robotic-assisted total knee arthroplasty (TKA) is a novel orthopedic technique. The workflow of robotic-assisted TKA is quite different from that of traditional manual TKA and may result incompletely different resection parameters. Understanding these parameters may help surgeons better perform robotic-assisted TKA. This study aims to analyze the specific resection parameters of robotic-assisted TKA.

METHODS

We retrospectively reviewed 85 MAKO-assisted TKA surgeries performed by three surgeons at our institution between May 2021 and November 2023. All patients had unilateral primary knee arthritis, and a Triathlon PS (Stryker) knee prosthesis was used. Intraoperative resection plan, radiological outcomes, and clinical outcomes were collected among them. The angle between the transepicondylar axis (TEA) and the femoral prosthesis axis was defined as rTEA, the angle between the posterior condylar axis (PCA) and the femoral prosthesis axis was defined as rPCA. The t-test and the Chi-square test (or Fisher's exact probability test) were used to determine differences in categorical variables.

RESULTS

rTEA averaged 2.7° (range, 0°-6.7°), and rPCA averaged 4.9° (range, 0.2°-9.6°). The mean resection of the medial distal femur was 7.7 mm (range, 3.0-12.5), that of the lateral tibial plateau was 6.4 mm (range, 1.5-13.0), and that of the medial posterior condyle of the femur was 10.6 mm (range, 6.5-17.5), whereas that of the lateral posterior condyle of the femur was 6.7 mm (range, 2.0-13.0).

CONCLUSION

Robotic-assisted TKA using the ligament balancing workflow generally resulted in greater external rotation than reported reference values for conventional manual TKA within the existing literature, with reference to both the TEA and PCA. In addition, tibial resection was generally less, and the joint line was generally shifted upwards.

Development and Validation of a Nomogram for Evaluating the Incident Risk of Pain Catastrophizing Among Patients Who Have Severe Knee Osteoarthritis Awaiting Primary Total Knee Arthroplasty

BACKGROUND

It is clinically important to anticipate the likelihood of pain catastrophizing in patients who undergo total knee arthroplasty (TKA). Persistent pain and diminished physical function following TKA are independently associated with preoperative pain catastrophizing. The purpose of this study was to develop and validate a nomogram model to predict pain catastrophizing in patients who have severe osteoarthritis undergoing primary TKA.

METHODS

Data were collected from patients who have severe osteoarthritis undergoing primary TKA at four tertiary general hospitals in Changsha, China, from September to December 2023. The study cohort was randomly divided into a training group and a validation group in the proportion of 70 to 30%. Least absolute shrinkage and selection operator regression analysis was utilized to select the optimal predictive variables for the model. A nomogram model was created using independent risk factors that were identified through multivariate regression analysis. Their performance was assessed using the concordance index and calibration curves, and their clinical utility was analyzed using decision curve analysis.

RESULTS

A total of 416 patients were included, 291 in the training group and 125 in the validation group. There were 115 (27.6%) who had pain catastrophizing. The predictors contained in the nomogram were pain intensity during activity, anxiety and depression, body mass index, social support, and household. The area under the curve of the nomogram was 0.976 (95% confidence interval = 0.96 to 0.99) for the training group and 0.917 (95% confidence interval = 0.88 to 0.96) for the validation group. The calibration curves confirmed the nomogram's accuracy, and decision curve analysis showed its strong predictive performance.

CONCLUSIONS

The comprehensive nomogram generated in this study was a valid and easy-to-use tool for assessing the risk of pain catastrophizing in preoperative TKA patients, and helped healthcare professionals to screen the high-risk population.

Predictive Validity of the Work, Osteoarthritis, or Joint Replacement Questionnaire for Return to Work After Total Knee Arthroplasty: A 12-Month Multicenter Prospective Cohort Study

BACKGROUND

After total knee arthroplasty (TKA), a minority of working patients are dissatisfied and experience a late or no return to work (RTW). This study aimed to identify whether a predefined grouping based on self-reported ability to perform work-related activities at three months post-TKA was associated with the ability to perform work-related activities at six and 12 months and RTW at three, six, and 12 months post-TKA.

METHODS

A 12-month multicenter prospective cohort study was performed among working TKA patients intending to RTW. The Work, Osteoarthritis, or Joint Replacement questionnaire score (range, 0 to 100) was used to assess patients' ability to perform work-related activities. Patients were grouped into early-, intermediate-, and late-recovery groups at three months post-TKA. The median age of the cohort (n = 182) was 59 years [interquartile range, 55 to 62], and 52% were women. Analyses included Spearman's correlation tests, and Kaplan-Meier survival analyses.

RESULTS

The early- (n = 54) and intermediate-recovery groups (n = 68) clinically improved their ability to perform work-related activities at three and 12 months, respectively, while the late-recovery group (n = 60) did not do so until 12 months (rs = 0.6, 0.27, and 0.25, respectively). The early-recovery group returned to work earlier (median 62 [interquartile range 41 to 90] days) compared to the intermediate- (75 [46 to 115] days) and late-recovery groups (84 [58 to 116] days) and resumed 100 percent of their working hours at six months versus 12 months in the intermediate- and late-recovery groups (rs = 0.37, 0.33, 0.1 at 3, 6, and 12 months, respectively).

CONCLUSIONS

At three months post-TKA, the work, osteoarthritis, or joint replacement questionnaire can be used to distinguish early-, intermediate-, and late-recovery groups, which are associated with the ability to perform work-related activities at six and 12 months post-TKA and RTW at three and six months.

Patient-reported outcomes and complications of a new-generation total knee system: a randomized controlled trial

BACKGROUND AND PURPOSE

 Documentation of new-generation implants' short-term performance could reassure surgeons and patients about their use, while awaiting the long-term outcome. Our aim was to compare the performance of a newer total knee arthroplasty (TKA) system with its predecessor, measured by patient-reported knee function, pain, and complication rate.

METHODS

We performed a multi-center, randomized, controlled trial (clinicaltrials.gov ID: NCT03073941). 314 patients with primary osteoarthritis were randomized to treatment with a Persona or NexGen cruciate-retaining TKA system and followed for 2 years. The primary outcome was measured with the patient-reported outcome (PRO) Oxford Knee Score (OKS) 2 years post-surgery. Secondary outcomes were the OKS-Activity and Participation questionnaire (OKS-APQ), Forgotten Joint Score (FJS), EQ-5D-3L, and number of complications during the study period. Responder analyses were performed using Patient Acceptable Symptom State (PASS) and Minimal Important Change (MIC) criteria.

RESULTS

 Primary outcome was available from 289 patients (92%). We found no difference in adjusted mean OKS between the groups 2 years post-surgery (0.1, 95% confidence interval -1.4 to 1.7). We found no significant differences in adjusted mean of secondary PROs, PRO time-weighted averages, proportion of patients with PASS or MIC, or complications 2 years post-surgery.

CONCLUSION

 We found no difference in OKS 2 years post-surgery, or in any secondary variables analyzed including complications, between the 2 TKA systems. Short-term safety and performance of the Persona TKA was comparable to its predecessor.

Recent applications of stimulus-responsive smart hydrogels for osteoarthritis therapy

Osteoarthritis is one of the most common degenerative joint diseases, which seriously affects the life of middle-aged and elderly people. Traditional treatments such as surgical treatment and systemic medication, often do not achieve the expected or optimal results, which leads to severe trauma and a variety of side effects. Therefore, there is an urgent need to develop novel therapeutic options to overcome these problems. Hydrogels are widely used in biomedical tissue repairing as a platform for loading drugs, proteins and stem cells. In recent years, smart-responsive hydrogels have achieved excellent results as novel drug delivery systems in the treatment of osteoarthritis. This review focuses on the recent advances of endogenous stimuli (including enzymes, pH, reactive oxygen species and temperature, etc.) responsive hydrogels and exogenous stimuli (including light, shear, ultrasound and magnetism, etc.) responsive hydrogels in osteoarthritis treatment. Finally, the current limitations of application and future prospects of smart responsive hydrogels are summarized.

Comparison between ligament balancing and measured resection in robot-assisted total knee arthroplasty: a 2-year follow up cohort study

PURPOSE

The two most commonly used techniques for gap balancing in robot-assisted total knee arthroplasty (RA-TKA) are measured resection (MR) and ligament balancing (LB). There are limited studies have reported differences in intraoperative and postoperative outcomes between MR-TKA and LB-TKA in RA-TKA. This study aims to compare the intraoperative and postoperative outcomes of primary RA-TKA between LB and MR techniques.

METHODS

This cohort study utilized prospectively collected data from a single center, spanning from January 2021 to December 2022. We compared the intraoperative procedures and postoperative clinical and imaging results between two groups.

RESULTS

The LB group had a thinner distal femur cut and a lower usage of thicker polyethylene. Additionally, the LB group exhibited a higher mean femoral component external rotation and greater tibial posterior slope. The rate of soft tissue release and bone recut was lower in the LB group, as was the mean C-reactive protein level.

CONCLUSION

In RA-TKA, LB offers advantages in soft tissue protection and bone mass preservation. However, no differences were observed in clinical and radiographic outcomes after a 2-year follow-up.

2023 International Academy of Toxicologic Pathology (IATP) Satellite Symposium: "Medical Device Safety Assessment: Pathology and Toxicology Perspective"

Medical devices represent a complex category of medicinal products with varying definitions depending on the regional jurisdiction of regulatory agencies. A common aspect of these definitions is that a medical device is intended to be used for specific medicinal purpose where the primary intended action of the device is not achieved through pharmacologic (or other chemical) means. While regional regulatory frameworks for medical devices are different than for pharmaceutical or biological products, medical device manufacturers are required to evaluate the safety and performance of these products in the context of their intended use. In biological safety evaluation, histopathology plays a relevant role in assessing medical device biocompatibility. This manuscript provides a broad overview of biocompatibility assessment with a deeper look at the role of the toxicologic pathologist in assessing innovative and emerging bone therapies. The content of this manuscript is based on individual presentations delivered at the 2023 International Academy of Toxicologic Pathology (IATP) Satellite Symposium held in conjunction with the Annual Congress of the European Society of Toxicologic Pathology (ESTP) on 26 September, in Basel, Switzerland.

Optimal exercise modalities and doses for therapeutic management of osteoarthritis of the knee

Osteoarthritis (OA) is a progressive osteoarticular disease affecting the whole joint. In the United Kingdom, OA is the most prevalent joint disease, with knee osteoarthritis (KOA) being the most common type of OA. Key symptoms of KOA include knee pain, stiffness, and loss of physical function. Different types of exercise can be performed in people with KOA, which exert different magnitudes of impact forces on the knee joint, whereby the National Institute for Health and Care Excellence (NICE) OA guidelines in fact recommend exercise as the core form of therapeutic OA management. However, the optimal type or dose - the cumulative intensity, duration, and frequency - of therapeutic exercise that most effectively provides KOA management is not currently known. This review aims to summarise and compare the literature, discussing optimal exercise modalities and doses for the management of KOA. All exercise modalities proved similarly beneficial at managing KOA with comparable improvements to knee pain, stiffness, and physical function, therefore with no optimal exercise modality identified. Benefits to KOA management was observed in everyone, including the elderly, obese, and those with severe KOA. Although, in those with severe KOA, walking was observed to only prevent further deterioration, rather than induce any symptomatic improvement. Furthermore, there was minimal difference between exercise modalities in relation to the improvements not only in KOA symptoms, but also modifiable KOA risk factors, adherence, adverse events, and QoL. Assessment of the dose-response relationship of each exercise modality showed that any dose of regular exercise was effective. Although, moderate intensity exercise performed three times weekly for 20-to-60-min appears optimal for KOA symptom control following most exercise modalities. Therefore, those with KOA should be encouraged to continue whatever exercise they currently do as should effectively manage symptoms, regardless of the modality or dose. However, those who do no exercise should use the present review in collaboration with clinicians via shared decision making to create a holistic exercise prescription. In summary, this review contributes to the literature through comprehensive discussion of different exercise modalities and doses in managing not only KOA symptoms, but modifiable KOA risk factors, exercise adherence, adverse events, and QoL. Additionally, summarised findings are discussed to give practical exercise recommendations to promote effective KOA management and recommendations for ongoing research.

Postoperative Weight Loss After Antiobesity Medications and Revision Risk After Joint Replacement

Importance

The 2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline concluded that obesity alone should not delay joint replacement. Therefore, a substantially increased utilization of joint replacement among patients with obesity could be expected. However, patients with obesity are at increased risk of revision, posing unique challenges as the surgery is complex and costly, and it remains unknown whether postoperative weight loss could decrease the risk of revision.

Objective

To examine the association of the proportion of postoperative weight loss following antiobesity medication use with the risk of revision among patients with obesity undergoing hip or knee replacement.

Design, Setting, and Participants

Using a target trial emulation, a causal inference framework, this retrospective cohort study investigated patients with obesity who underwent hip or knee replacement. Data were from the IQVIA Medical Research Database (2000-2023). Statistical analysis was performed from October 2023 to June 2024.

Main Outcomes and Measures

Emulated analyses of a hypothetical target trial were assessed for the association of small-to-moderate (2%-10%) or large (≥10%) weight loss after initiating antiobesity medications (orlistat, sibutramine, glucagon-like peptide-1 receptor agonists, and rimonabant) within 1 year with the risk of 5-year and 10-year revision after initiation of antiobesity medications.

Results

Among 3691 qualified participants (mean [SD] age, 64.7 [9.3] years; 2322 [62.9%] women), the 5-year risks of revision were 5.6%, 4.4%, and 3.7% for weight gain or stable, small-to-moderate weight loss, and large weight loss groups, respectively. Compared with the weight gain or stable group, the hazard ratios (HRs) were 0.75 (95% CI, 0.55-1.04) for the small-to-moderate weight loss group and 0.57 (95% CI, 0.36-0.91) for the large weight loss group. Similar results were observed when the analyses were performed separately for hip or knee replacement. The HRs for revision were 0.55 (95% CI, 0.32-0.93) for small-to-moderate weight loss and 0.49 (95% CI, 0.25-0.97) for large weight loss groups compared with the weight gain or stable group in patients undergoing knee replacement; the corresponding HRs for revision were 0.82 (95% CI, 0.54-1.25) and 0.53 (95% CI, 0.30-0.93) in patients undergoing hip replacement. Consistent findings were obtained regarding the association of weight loss with the 10-year risks after initiating antiobesity medications.

Conclusions and Relevance

In this cohort study using a target trial emulation, a higher proportion of weight loss after initiating antiobesity medications within 1 year was associated with a lower risk of 5-year and 10-year revision among patients with obesity undergoing joint replacement. These results suggest that antiobesity medication use, with relatively safe and sustainable weight loss, may be an effective strategy for improving implant survivorship of hip and knee replacements in the obese population.

Chemical neurolysis of genicular nerves for chronic non-cancer knee pain: a scoping review

OBJECTIVE

Chemical neurolysis of the genicular nerves is a treatment option for intractable non-cancer knee pain. This scoping review synthesizes the available literature on the effectiveness, adverse events, and procedural techniques of chemical neurolysis of genicular nerves for the management of knee pain.

DESIGN

Scoping review.

SETTING

All clinical and research settings.

SUBJECTS

Adult participants with chronic non-cancer knee pain undergoing chemical neurolysis of genicular nerves.

METHODS

A literature search in MEDLINE, EMBASE, and Cochrane Library was conducted up to September 4, 2023. Articles were searched via terms and keywords relating to "knee," "pain," "knee osteoarthritis," "ablation," "alcohol," "phenol," and "chemical neurolysis." Included articles were full-text primary studies and in English. Data were extracted by 2 independent reviewers using an electronic database.

RESULTS

Eight studies were included in this review (including 1 randomized controlled trial), comprising 192 patients. Of the 8 studies, 4 used phenol, 3 used alcohol, and 1 used either alcohol or phenol for chemical neurolysis. Fluoroscopy, ultrasound guidance, or both were used for nerve target identification. All studies demonstrated that chemical neurolysis resulted in improved pain or functional outcomes, with no serious adverse events reported.

CONCLUSIONS

Chemical neurolysis of the genicular nerves is a promising treatment strategy for chronic knee pain. Interpretation of the available studies is limited by study heterogeneity and small sample sizes. High-quality randomized controlled trials are required to clarify the selection of appropriate nerve targets and choice of image guidance and to compare with other ablative modalities.

STUDY REGISTRATION

Open Science Framework (https://osf.io/jg8wh).

Construction and high-throughput screening of gradient nanowire coatings on titanium surface towards ameliorated osseointegration

Surface nano-modification has emerged as an effective strategy to enhance osseointegration of titanium (Ti) implants. Despite its promise, rational optimization of surface nanomorphology for ameliorated osseointegration remains a significant challenge. Our research pioneering developed a one-step alkali etching technique to produce a gradient nanowire coating with continuously varied dimensions on Ti surfaces, which was subsequently served as a versatile platform for high-throughput screening of optimal dimensions to enhance osseointegration. The results showed that macrophages (MФs) that mainly governed the initial inflammatory reaction exhibited a polarization tendency towards pro-healing M2 phenotype with decreased nanowire dimension due to nanomorphology-mediated focal adhesion formation and activation of its downstream signaling pathways (typically PI3K-Akt). Simultaneously, small-sized nanowires with diameter of 5.63-14.25 nm and inter-spacing of 29.42-57.97 nm were conductive to angiogenesis of endothelial cells (ECs) and osteogenesis of bone marrow mesenchymal stem cells (BMSCs), which may share similar mechanisms of MФs. The in vivo results well corroborated these in vitro observations. The knowledge gained from the present work not only advance our understanding of the interaction between surface morphology and cells, but also potentially pave the way for efficient and cost-effective design of advanced biomaterial surfaces for better osseointegration.

Adductor Canal Block Combined With IPACK Block for Postoperative Analgesia After Total Knee Arthroplasty: A Retrospective Cohort Study

Background

There is no consensus on whether adductor canal block (ACB) combined with infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block can further increase analgesia and reduce opioid consumption after total knee arthroplasty (TKA) compared with ACB and periarticular infiltration analgesia (PIA).

Purpose

This study aimed to evaluate the effectiveness of combining ACB and PACK block on analgesia and functional recovery following TKA.

Methods

A retrospective cohort study was conducted involving 386 patients who underwent primary unilateral TKA at our institution from January 2020 to October 2022. Patients were divided into 3 groups and treated with PIA, ACB, or ACB combined with IPACK block, respectively. Primary outcomes were postoperative morphine consumption and visual analogue scale (VAS) pain scores. Secondary outcomes included functional recovery, evaluated by knee range of motion, quadriceps strength, daily mobilization distance, and postoperative length of stay. Other outcomes included incidence of complications.

Results

Patients in the ACB + IPACK group had significantly less morphine consumption on postoperative day 1 and during hospitalization than patients in the PIA and ACB groups. Furthermore, the ACB + IPACK group had significantly lower VAS scores at rest and during motion at 6, 12, and 24 hours postoperatively (but not at other time points), better knee range of motion on postoperative days 1 and 2 (but not day 3), and a greater daily mobilization distance on postoperative day 1 (but not days 2 and 3). The ACB + IPACK group had significantly lower incidences of postoperative nausea and vomiting than the PIA and ACB groups.

Conclusion

This retrospective cohort study suggests that a combination of ACB and IPACK block may have a greater effect than PIA or ACB alone on analgesia following TKA, while providing better functional recovery. Further study is warranted.

Current Concepts and Clinical Applications in Cartilage Tissue Engineering

Cartilage injuries are extremely common in the general population, and conventional interventions have failed to produce optimal results. Tissue engineering (TE) technology has been developed to produce neocartilage for use in a variety of cartilage-related conditions. However, progress in the field of cartilage TE has historically been difficult due to the high functional demand and avascular nature of the tissue. Recent advancements in cell sourcing, biostimulation, and scaffold technology have revolutionized the field and made the clinical application of this technology a reality. Cartilage engineering technology will continue to expand its horizons to fully integrate three-dimensional printing, gene editing, and optimal cell sourcing in the future. This review focuses on the recent advancements in the field of cartilage TE and the landscape of clinical treatments for a variety of cartilage-related conditions.

Validation of a Novel Landmark-guided Intra-articular Postero-medial Surgeon-administered Injection Technique

Background

This study aimed to define an intra-articular surgeon-administered technique that may be comparable to ultrasound (US)-guided adductor canal block (ACB).

Methods

Five cadaver lower limbs were examined. An anesthesiologist administered a US-guided ACB using 20 mL of dilute indocyanine dye. An orthopedic surgeon performed a medial parapatellar arthrotomy and introduced an 18-gauge needle 1-2 cm proximal to the palpated adductor tubercle angled posteromedially. Needle position and dye spread were fluoroscopically documented.

Results

This technique consistently reached the infrapatellar branch of the saphenous nerve, nerve to the vastus medialis muscle, and posterior capsule, with minimal proximal dye spread.

Conclusions

This technique may be an efficient complement to ACB or surgeon infiltration or an alternative to US-guided ACB when it is not available.

Excellent results of restricted kinematic alignment total knee arthroplasty at a minimum of 10 years of follow-up

PURPOSE

While restricted kinematic alignment (rKA) total knee arthroplasty (TKA) with cemented implants has been shown to provide a similar survivorship rate to mechanical alignment (MA) in the short term, no studies have reported on the long-term survivorship and function.

METHODS

One hundred four consecutive cemented cruciate retaining TKAs implanted using computer navigation and following the rKA principles proposed by Vendittoli were reviewed at a minimum of 10 years after surgery. Implant revisions, reoperations and clinical outcomes were assessed using knee injury and osteoarthritis outcome score (KOOS), forgotten joint score (FJS), patients' satisfaction and joint perception questionnaires. Radiographs were analyzed to identify signs of osteolysis and implant loosening.

RESULTS

Implant survivorship was 99.0% at a mean follow-up of 11.3 years (range: 10.3-12.9) with one early revision for instability. Patients perceived their TKA as natural or artificial without limitation in 50.0% of cases, and 95.3% were satisfied or very satisfied with their TKA. The mean FJS was 67.6 (range: 0-100). The mean KOOS were as follows: pain 84.7 (range: 38-100), symptoms 85.5 (range: 46-100), function in daily activities 82.6 (range: 40-100), function in sport and recreation 35.2 (range: 0-100) and quality of life 79.1 (range: 0-100). No radiological evidence of implant aseptic loosening or osteolysis was identified.

CONCLUSION

Cemented TKA implanted with the rKA alignment protocol demonstrated excellent long-term implant survivorship and is a safe alternative to MA to improve patient function and satisfaction.

LEVEL OF EVIDENCE

Level IV, continuous case series with no comparison group.

Advances in the pathology and treatment of osteoarthritis

BACKGROUND

Osteoarthritis (OA), a widespread degenerative joint disease, predominantly affects individuals from middle age onwards, exhibiting non-inflammatory characteristics. OA leads to the gradual deterioration of articular cartilage and subchondral bone, causing pain and reduced mobility. The risk of OA increases with age, making it a critical health concern for seniors. Despite significant research efforts and various therapeutic approaches, the precise causes of OA remain unclear.

AIM OF REVIEW

This paper provides a thorough examination of OA characteristics, pathogenic mechanisms at various levels, and personalized treatment strategies for different OA stages. The review aims to enhance understanding of disease mechanisms and establish a theoretical framework for developing more effective therapeutic interventions.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review systematically examines OA through multiple perspectives, integrating current knowledge of clinical presentation, pathological mechanisms, and associated signaling pathways. It assesses diagnostic methods and reviews both pharmacological and surgical treatments for OA, as well as emerging tissue engineering approaches to manage the disease. While therapeutic strategies such as exercise, anti-inflammatory drugs, and surgical interventions are employed to manage symptoms and modify joint structure, none have been able to effectively halt OA's advancement or achieve long-lasting symptom relief. Tissue engineering strategies, such as cell-seeded scaffolds, supportive matrices, and growth factor delivery, have emerged as promising approaches for cartilage repair and OA treatment. To combat the debilitating effects of OA, it is crucial to investigate the molecular basis of its pathogenesis and seek out innovative therapeutic targets for more potent preventive and treatment strategies.

Unloader brace or high tibial osteotomy in the treatment of the young patient with medial knee osteoarthritis: a randomized controlled trial

BACKGROUND AND PURPOSE

 For medial knee osteoarthritis (OA), operative and nonoperative treatment options are available. Two widely applied unloading therapies are a valgus unloader brace and a high tibial osteotomy (HTO). We aimed to compare the effects of a valgus unloader knee brace with an HTO on knee pain after 1 year in patients with symptomatic medial knee OA.

METHODS

We recruited patients from 9 Dutch hospitals between August 2014 and February 2019 for an open-labeled multi-center randomized controlled trial (Dutch Trial Register NL4200). Patients aged 18 to 65 years with symptomatic medial compartmental knee OA were randomized to either a valgus unloader brace or an HTO. The primary outcome was the pain subscale of the Knee injury and Osteoarthritis Outcome score (KOOS) after 1 year. Patients were evaluated at 3, 6, 9, 12, and 24 months.

RESULTS

 51 patients were included in the study, of whom 23 were randomized to the unloader brace and 28 to the HTO. The HTO, compared with the unloader brace, showed a significant and clinically relevant difference at 12 months of follow-up in KOOS pain of -28 (95% confidence interval -43 to -13).

CONCLUSION

 We found that, on group level, an HTO is more effective in reducing knee pain than an unloader brace after 12 months.

Image-based robotic (ROSA® knee system) total knee arthroplasty with inverse kinematic alignment compared to conventional total knee arthroplasty : Study protocol and the inverse kinematic alignment in 8-steps using the ROSA® Knee system for knee balancing technique explained

INTRODUCTION

In 2020, 368 million people globally were affected by knee osteoarthritis, and prevalence is projected to increase with 74% by 2050. Relatively high rates of dissatisfactory results after total knee arthroplasty (TKA), as reported by approximately 20% of patients, may be caused by sub-optimal knee alignment and balancing. While mechanical alignment has traditionally been the goal, patient-specific alignment strategies are gaining interest. Robotic assistance could potentially facilitate implementation of these alignment strategies through data-based surgical planning, accurate execution of the surgical plan and validation. The clinical value of surgical assistance in diverging from mechanical alignment remains to be investigated. In the present study, robotic-assisted TKA will be performed to pursue inverse kinematic alignment (iKA) within predefined boundaries, focusing on restoring native tibia joint line.

METHODS

This randomized controlled trial evaluates clinical effectiveness of robotic-assisted TKA (ROSA® Knee System, Zimmer Biomet, Montreal, Quebec, Canada) aiming for iKA compared to conventional TKA aiming for mechanical alignment. A total of 150 participants will be randomized (1:1) to either treatment to provide an 80% power for a 4.8-point clinically important difference in the primary outcome measure, the Oxford Knee Score (OKS) 12 months after surgery. Allocation was achieved using computer-based randomization. Outcomes will be analyzed using linear mixed models with time and group as main factors and interaction-term. Secondary outcomes include clinical metrics (leg alignment, implant and patient survival), surgical parameters (adverse events, surgery duration, blood loss, hospital stay length, medication use), patient-reported outcomes (symptoms, quality of life, pain), mobility and physical activity measurements, metabolic syndrome, cost-efficacy, and gait and continuous glucose monitoring.

ETHICS AND DISSEMINATION

This study has been approved by the Medical Ethical Committee Zuyd and Zuyderland Medical Centre (NL79161.096.21/METCZ20220006), September 2022.

TRIAL REGISTRATION NUMBER

NCT05685693 (clinicaltrials.gov).

Adverse Events Associated with Surgically Implanted Temporomandibular Joint Devices

INTRODUCTION

Temporomandibular disorder (TMD) is a common, yet potentially debilitating syndrome that negatively impacts patient quality of life. In patients with severe variants of TMD, temporomandibular joint (TMJ) devices have been utilized to replace the joint altogether. However, the risk profile and consequent cost-benefit ratio of these devices are largely debated. This report aimed to provide further insight on the safety of surgically implanted TMJ devices by analyzing adverse events from the Manufacturer and User Facility Device Experience (MAUDE) database.

METHODS

Inclusion criteria consisted of all MAUDE reports from January 2013 to January 2023 containing the keyword "TMJ." Duplicate reports, preimplantation events, reports extrapolated from published literature reviews, and those not related to TMJ implants were excluded from analysis. Adverse events were extracted, reviewed, and categorized according to complication type, management strategy, device manufacturer, causes of device malfunction, and reporting timeframe. Nonparametric χ2 and Levene's test were used to compare average values between groups with a two-tailed p value of 0.05 being considered statistically significant.

RESULTS

A total of 385 adverse event reports were reviewed. The most common complications were infection (59, 25.9%), ankylosis (57, 25.0%), and pain (33, 14.5%). The most common device failures were implant malposition (28, 39.4%), implant dislodgement (22, 31.0%), and screw osseointegration failure (11, 15.5%). Upon assessment of revision surgeries, those undertaken to address infections had the highest rate of device explantation (77%). In a separate analysis of 28 adverse events submitted directly by patients, infection was most common self-reported complication (42.9%). Comparison of device manufacturers revealed that Biomet implants had significantly more reports of pain (χ2 = 10.21, p = 0.003), whereas Stryker implants had more infections (χ2 = 29.87, p < 0.001).

CONCLUSION

In summary, this in-depth analysis of adverse events provides a safety profile of TMJ implants. Understanding the complication types, management strategies, and outcomes according to device manufacturer may help set patient expectations and improve patient care.

Are Current Patient-Reported Outcome Measures Fit for Purpose to Evaluate Unicompartmental Knee Arthroplasty?

The optimal procedure for isolated end-stage medial compartment knee osteoarthritis (OA) remains uncertain, with debate persisting between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The aim of this narrative review is to evaluate current outcome measures in knee arthroplasty (KA) and explore how evolving patient populations and technological advancements may necessitate the use of different patient-reported outcome measures (PROMs) for evaluating UKA. While UKA offers potential advantages over TKA in early pain relief and functional outcomes, most randomised control trials using traditional PROMs have failed to show definitive superiority. The recent introduction of robotic assistance may have further enhanced the benefits of UKA. However, it remains uncertain whether the advantages outweigh the higher revision rates associated with UKA. Although traditional PROMs, such as the Oxford Knee Score or Knee Injury and Osteoarthritis Outcome Score, were designed for the KA population of 30 years ago, they continue to be employed today. The current KA population, particularly those undergoing UKA, are typically younger, physically fitter, and have higher functional demands than those for whom traditional PROMs were originally designed. As a result, these PROMs are now limited by ceiling effects. High-performance PROMs, such as the Forgotten Joint Score-12 or the metabolic equivalent of task score, have recently been utilised for high-demand patients and do not have postoperative ceiling effects. Return to work and sport are also important outcomes that are often overlooked for younger, high-demand patients. Future studies should aim to define the differences between UKA and TKA populations, identify patient factors that predict UKA success, and validate high-performance PROMs for UKA. This will provide deeper insights into the functional benefits of UKA and TKA, enabling patients and surgeons to make more informed decisions regarding implant selection.

Prevalence of metal implants among US adults aged 40 years and older

Metal implants are commonly used in clinical practice. However, little is known regarding the prevalence of metal implants. Therefore, this study aimed to evaluate the prevalence of metal implants in the United States (US) among individuals aged ≥ 40 years. This study conducted a serial cross-sectional analysis of US adults aged ≥ 40 years who participated in the National Health and Nutrition Examination Survey (NHANES) (2015-2016 and 2017-March 2020). Self-reported questionnaires were used to assess whether the participants had metal implants inside their bodies. The primary outcome was the prevalence of metal implants among adults aged 40 years and older. Furthermore, weighted logistic regression analysis was employed to determine the changes in the prevalence of metal implants from 2015 to March 2020. Moreover, this study investigated the variation in metal implant prevalence by demographic factors based on the pooled NHANES cycles. All analyses were conducted based on 3,736 participants from the NHANES 2015-2016 and 6,387 participants from the NHANES 2017-March 2020. This study observed a high prevalence of metal implants among adults aged 40 and older (2015-2016: 27.23%; 2017-March 2020: 31.53%). Moreover, the results of the weighted logistic regression analysis showed that the prevalence of metal implants significantly increased from 2015 to March 2020, especially among older individuals, men, and White individuals. In addition, the results of the weighted logistic regression analysis indicated that the metal implant prevalence differed by age and race/ethnicity, in which older individuals and White individuals showed a significantly higher prevalence of metal implants than younger individuals and non-White individuals, respectively. There was a high prevalence of metal implants among US adults aged 40 and older, and the prevalence of metal implants significantly increased from 2015 to March 2020. Therefore, more attention needs to be paid to this special population, and it may be necessary to ensure accessibility and affordability and assess the potential long-term health impacts of metal implants, considering the increased prevalence of metal implants.

Local antimicrobial delivery systems for prophylaxis and treatment of periprosthetic traumatological infections

Infections associated with implants are the most serious complications in joint replacement surgeries and can jeopardize the functionality of orthopedic implants. Local antimicrobial delivery could enable antibiotics to attain concentrations above the minimum inhibitory concentration (MIC) threshold at the joint replacement site while preventing systemic side effects. Therefore, there is a dire need for the development of improved biomaterial-based delivery systems for local antibiotic administration in prosthetic infections. In this context, this review highlights the latest breakthroughs in the design of biomaterial-based formulations intended for the prophylaxis and treatment of prosthetic infections. Delivery systems for distinct forms of administration (i.e., direct intra-articular administration, loading into bone cements, coating of implant surfaces, or loading into hydrogels) are here comprehensively compiled with a focus on the design of microparticles and nanosystems for local antimicrobial administration and their impact on distinct in vitro and in vivo models of implant infections.