The impact of osteoarthritis: implications for research

Ankle osteoarthritis: Toward new understanding and opportunities for prevention and intervention

The ankle infrequently develops primary osteoarthritis (OA), especially when compared to the hip and the knee. Ankle OA instead generally develops only after trauma. The consequences of end-stage ankle OA can nonetheless be extremely debilitating, with impairment comparable to that of end-stage kidney disease or congestive heart failure. Disconcertingly, evidence suggests that ankle OA can develop more often than is generally appreciated after even low-energy rotational ankle fractures and chronic instability associated with recurrent ankle sprains, albeit at a slower rate than after more severe trauma. The mechanisms whereby ankle OA develops after trauma are poorly understood, but mechanical factors are implicated. A better understanding of the prevalence and mechanical etiology of post-traumatic ankle OA can lead to better prevention and mitigation. New surgical and conservative interventions, including improved ligamentous repair strategies and custom carbon fiber bracing, hold promise for advancing treatment that may prevent residual ankle instability and the development of ankle OA. Studies are needed to fill in key knowledge gaps here related to etiology so that the interventions can target key factors. New technologies, including weight bearing CT and biplane fluoroscopy, offer fresh opportunities to better understand the relationships between trauma, ankle alignment, residual ankle instability, OA development, and foot/ankle function. This paper begins by reviewing the epidemiology of post-traumatic ankle OA, presents evidence suggesting that new treatment options might be successful at preventing ankle OA, and then highlights recent technical advances in understanding of the origins of ankle OA to identify directions for future research.

TBBPA exposure causes cartilage cell damage in both in vitro and in vivo models

Tetrabromobisphenol A (TBBPA) is a widely used flame retardant. TBBPA is a persistent pollutant that is difficult to degrade and causes sustained pollution to the environment. TBBPA has been detected in human blood and tissues, and studies indicate it causes various toxicological damages to tissues and cells. To date, the toxicological effects of TBBPA on chondrocytes are not fully understood. Here, we evaluated the toxicological effects of TBBPA on chondrocytes and tissues. For this, human- and mouse-derived chondrocyte models were used to analyze the toxicological effects of TBBPA. Physiological concentrations of TBBPA were used to stimulate chondrocytes. Indirect immunofluorescence, flow cytometry, and biochemical assays were utilized to investigate TBBPA's toxicological impact on chondrocytes. The CCK8 experiment indicated that TBBPA reduced chondrocyte proliferation. ELISA and Western blot results indicated that TBBPA increased inflammatory factor expression in chondrocytes. We also found that TBBPA caused oxidative stress in chondrocytes. Mechanistic study showed that TBBPA triggered a imbalance in the homeostasis of calcium ions, leading to mitochondrial depolarization, which induces inflammation and oxidative stress of chondrocytes. In vivo model, our research showed that TBBPA caused inflammation in knee joint cartilage. Safranin O-Fast Green and H&E staining revealed cartilage tissue damage following TBBPA treatment. TBBPA increased MMP9 and MMP13 expression and down-regulated COL2 expression. In summary, we assessed TBBPA's impact on chondrocytes. The experimental data indicate that TBBPA causes damage to chondrocytes. This study establishes a basis for future research on the toxicological impacts of TBBPA.

Role of Piezoelectricity in Disease Diagnosis and Treatment: A Review

Because of their unique electromechanical coupling response, piezoelectric smart biomaterials demonstrated distinctive capability toward effective, efficient, and quick diagnosis and treatment of a wide range of diseases. Such materials have potentiality to be utilized as wireless therapeutic methods with ultrasonic stimulation, which can be used as self-powered biomedical devices. An emerging advancement in the realm of personalized healthcare involves the utilization of piezoelectric biosensors for a range of therapeutic diagnosis such as diverse physiological signals in the human body, viruses, pathogens, and diseases like neurodegenerative ones, cancer, etc. The combination of piezoelectric nanoparticles with ultrasound has been established as a promising approach in sonodynamic therapy and piezocatalytic therapeutics and provides appealing alternatives for noninvasive treatments for cancer, chronic wounds, neurological diseases, etc. Innovations in implantable medical devices (IMDs), such as implantable piezoelectric energy generator (iPEG), offer significant advantages in improving physiological functioning and ability to power a cardiac pacemaker and restore the heart function. This comprehensive review critically evaluates the role of piezoelectricity in disease diagnosis and treatment, highlighting the implication of piezoelectric smart biomaterials for biomedical devices. It also discusses the potential of piezoelectric materials in healthcare monitoring, tissue engineering, and other medical applications while emphasizing future trends and challenges in the field.

Intra-articular injection of platinum nanozyme-loaded silk fibroin/pullulan hydrogels relieves osteoarthritis through ROS scavenging and ferroptosis suppression

Reactive oxygen species (ROS)-mediated ferroptosis plays a critical role in the development of osteoarthritis (OA). Consequently, it is speculated that anti-ferroptosis agents could represent a novel therapeutic strategy for managing OA. In this study, a hydrogel incorporating platinum (Pt) nanozyme was synthesized by dispersing Pt nanoparticles (NPs) within a matrix of silk fibroin (SF) and oxidized pullulan (oxPL). This hydrogel allows for a substantial and sustained release of up to 30 days. The gelation time (from 140.3 ± 42.3 s to 460.0 ± 40.0 s), swelling capacity (from 57.7 ± 3.8 % to 24.0 ± 7.0 %), and degradation rate (from 60.3 ± 4.7 % to 32.0 ± 4.6 %) of the hydrogels can be modulated by adjusting the Pt NP content. The Pt@SF/oxPL hydrogel effectively eliminates ROS due to its catalase-like and superoxide dismutase-like enzymatic properties. In vitro studies demonstrated that Pt@SF/oxPL efficiently mitigated the process of ferroptotic cell death in chondrocytes. More critically, intra-articular administration of Pt@SF/oxPL showcased therapeutic advantages by both protecting and stimulating the regeneration of cartilage throughout the progression of OA. Collectively, this study suggests that Pt@SF/oxPL hydrogels could potentially serve as an effective treatment for OA, presenting a novel nanozyme-based therapeutic approach for this condition.

Microfragmented adipose tissue injection reduced pain compared to a saline control among patients with symptomatic knee osteoarthritis during one-year follow-up: a randomized, controlled trial

PURPOSE

To evaluate the effectiveness of microfragmented adipose tissue (MFAT) for pain relief and improved joint functionality in knee OA in a randomized, controlled clinical trial with 1-year follow-up.

METHODS

Seventy-five patients were stratified by baseline pain level, and randomized to one of three treatment groups: MFAT, corticosteroid (CS), or saline control (C) injection. Patients 18 years of age or older, diagnosed with symptomatic knee osteoarthritis, with radiographic evidence of knee osteoarthritis and a visual analog pain scale (VAS) score of 3/10 or greater were included. Patients were excluded if they had any prior intra-articular knee injection, current knee ligamentous instability or an allergy to lidocaine/corticosteroid. The VAS pain scale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Knee Injury and Osteoarthritis Outcome score (KOOS) were recorded pre-procedure and at 2 weeks, 6 weeks, 3 and 6 months, and 1 year follow-up.

RESULTS

MFAT demonstrated consistent and statistically significant improvements across all primary outcome measures for joint pain and functionality compared to C. For MFAT, there was a significant improvement over baseline at each follow-up, with median (95% CI) KOOS Pain score changes of 18.1 (11.1, 26.4) at week 2 to 27.8 (19.4, 37.5) at 1 year. For CS, the median KOOS pain score reached a maximum of 22.2 (15.3, 30.6) at week 2, only to level off to 13.9 (-2.8, 29.2), a level not statistically different from baseline, at 1 year. The median changes for C hovered around 6-11 points, with statistically significant improvements over baseline indicating a placebo effect. Similar trends were seen for the WOMAC Pain score and VAS Pain score.

CONCLUSIONS

In this study, MFAT demonstrated a clinically significant improvement in primary outcome scores compared with a saline control group, while the corticosteroid group only showed statistically significant improvement compared to the control group at 2 and 6 weeks. This finding indicates that MFAT may be a viable alternative treatment for patients with knee OA that fall into the orthopaedic treatment gap.

A single-center retrospective chart review of percutaneous PNS for treatment of chronic shoulder pain

Objective

The present IRB-approved retrospective chart review describes the use of a 60-day PNS treatment for shoulder pain at a single center in 60 total consecutive patients.

Background

Chronic shoulder pain affects an increasing number of patients per year and is especially prevalent in elderly populations. Percutaneous peripheral nerve stimulation (PNS) treatment targeting the nerves of the shoulder has been shown to reduce pain in prospective clinical studies and in analysis of real-world data.

Methods

Data were extracted from the electronic medical records of patients who had previously undergone percutaneous PNS treatment for chronic shoulder pain. Demographic data and treatment characteristics were summarized alongside treatment outcomes.

Results

Overall, 84 % (49/58) of patients reported substantial (≥50 %) pain relief at the end-of-treatment. The records for 2 patients did not include patient-reported percent pain relief. The average indwelling period for leads (i.e., treatment period) was 57 days. Findings on treatment effectiveness were consistent when the patient population was stratified by cause of pain, duration living with pain, and presence of pain-modifying comorbidities. Stimulation paradigms were identified and categorized by the nerve target and stimulation frequency (e.g., motor stimulation, sensory stimulation, or bimodal stimulation).

Conclusions

These results indicate percutaneous PNS is an effective treatment for patients with various shoulder pain histories, and while all stimulation paradigms were effective at reducing pain, patients who received bimodal PNS reported the greatest pain relief. Key limitations of the study included heterogeneous shoulder pain etiologies among patients and sparse availability of long-term follow-up data. These data support existing real-world and prospective clinical evidence on the efficacy of 60-day PNS treatment at treating chronic pain and provide valuable insights into its use in clinical practice.

The Association Between the Development of Cam Morphology During Skeletal Growth in High-Impact Athletes and the Presence of Cartilage Loss and Labral Damage in Adulthood: A Prospective Cohort Study With a 12-Year Follow-up

BACKGROUND

Cam morphology develops during skeletal growth, but its influence on cartilage and the labrum in high-impact athletes later in life is unknown.

PURPOSE

To (1) explore the association between the presence and duration of cam morphology during adolescence and the cartilage and labral status 7 to 12 years later and (2) report the prevalence of cartilage loss and labral damage in a population of young male athletes (<32 years old) who played professional soccer during skeletal growth.

STUDY DESIGN

Cohort study (Prognosis); Level of evidence, 2.

METHODS

A total of 89 healthy male academy soccer players from the Dutch soccer club Feyenoord (aged 12-19 years) were included at baseline. At baseline and 2.5- and 5-year follow-ups, standardized supine anteroposterior pelvis and frog-leg lateral radiographs of each hip were obtained. At 12-year follow-up, magnetic resonance imaging of both hips was performed. Cam morphology was defined by a validated alpha angle ≥60° on radiographs at baseline or 2.5- or 5-year follow-up when the growth plates were closed. Hips with the presence of cam morphology at baseline or at 2.5-year follow-up were classified as having a "longer duration" of cam morphology. Hips with cam morphology only present since 5-year follow-up were classified as having a "shorter duration" of cam morphology. At 12-year follow-up, cartilage loss and labral abnormalities were assessed semiquantitatively. Associations were estimated using logistic regression, adjusted for age and body mass index.

RESULTS

Overall, 35 patients (70 hips) with a mean age of 28.0 ± 2.0 years and mean body mass index of 24.1 ± 1.8 participated at 12-year follow-up. Cam morphology was present in 56 of 70 hips (80%). The prevalence of cartilage loss was 52% in hips with cam morphology and 21% in hips without cam morphology (adjusted odds ratio, 4.52 [95% CI, 1.16-17.61]; P = .03). A labral abnormality was present in 77% of hips with cam morphology and in 64% of hips without cam morphology (adjusted odds ratio, 1.99 [95% CI, 0.59-6.73]; P = .27). The duration of cam morphology did not influence these associations.

CONCLUSION

The development of cam morphology during skeletal growth was associated with future magnetic resonance imaging findings consistent with cartilage loss in young adults but not with labral abnormalities.

Hip and pelvic geometry as predictors of knee osteoarthritis severity

Malalignment is one of the most critical risk factors for knee osteoarthritis (KOA). Biomechanical factors such as knee varus or valgus, hip-knee-ankle angle, and femoral anteversion affect KOA severity. In this study, we aimed to investigate KOA severity predictive factors based on hip and pelvic radiographic geometry. In this cross-sectional study, 125 patients with idiopathic KOA were enrolled. Two investigators evaluated the knee and pelvic radiographs of 125 patients, and 16 radiological parameters were measured separately. KOA severity was categorized based on the medial tibiofemoral joint space widths (JSW). Based on JSW measurements, 16% (n = 40), 8.8% (n = 22), 16.4% (n = 41), and 56.8% (n = 147) were defined as grades 0, 1, 2, 3, respectively. There were significant differences between the JSW groups with respect to hip axis length, femoral neck-axis length, acetabular width, neck shaft angle (NSA), outer pelvic diameter, midpelvis-caput distance, acetabular-acetabular distance, and femoral head to femoral head length (P < .05). Two different functions were obtained using machine learning classification and logistic regression, and the accuracy of predicting was 74.4% by using 1 and 89.6% by using both functions. Our findings revealed that some hip and pelvic geometry measurements could affect the severity of KOA. Furthermore, logistic functions using predictive factors of hip and pelvic geometry can predict the severity of KOA with acceptable accuracy, and it could be used in clinical decisions.

Comparison of Trends and Complications of Unicompartmental Knee Arthroplasty Versus Periarticular Knee Osteotomy Among ABOS Part II Oral Examination Candidates

Background

While unicompartmental knee arthroplasty (UKA) and osteotomy procedures are commonly used to treat knee osteoarthritis, the differences in complication profiles between procedures are still poorly understood.

Purpose/Hypothesis

The purpose of this study was to assess the trends and complication rates of UKA and periarticular knee osteotomy for knee osteoarthritis among newly trained surgeons by using the American Board of Orthopaedic Surgery (ABOS) Part II Oral Examination Case List database. It was hypothesized that more adult reconstruction fellowship-trained surgeons would perform UKA, while more sports medicine fellowship-trained surgeons would perform osteotomy, and that both procedures would have low rates of complications.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

The ABOS database was queried for patients who underwent UKA, high tibial osteotomy, and distal femoral osteotomy procedures in examination years 2011 to 2021. Patient characteristics, surgeon fellowship training history, surgeon-reported postoperative complications, and readmission and reoperation rates were recorded. Comparisons between the UKA and osteotomy groups were performed using independent t tests and chi-square tests.

Results

There were 2524 patients in the UKA group and 270 patients in the osteotomy group. The majority of newly trained surgeons performing UKA (70.5%) had fellowship training in adult reconstruction, while the majority of those performing osteotomy (57.8%) had fellowship training in sports medicine (P < .001). The incidence of UKA and osteotomy increased during the study period (18.8 UKAs and 1.8 osteotomies performed per 10,000 cases in 2011 vs 39.5 UKAs and 4.2 osteotomies performed per 10,000 cases in 2021). Rates were significantly higher for osteotomy compared with UKA regarding anesthetic complications (2.2% vs 0.6%; P = .015), surgical complications (23.7% vs 7.3%; P < .001), reoperation (5.2% vs 1.9%; P = .002), and infection (6.7% vs 1.4%; P < .001). There were no significant differences in rates of medical complication, readmission, deep vein thrombosis, pulmonary embolism, or stiffness/arthrofibrosis.

Conclusion

Among newly trained surgeons taking the ABOS Part II Oral Examination, the incidence of UKA and periarticular knee osteotomy increased over the past decade. Compared with UKA, complication rates were higher after osteotomy, with an overall surgical complication rate of 23.7%.

In vivo human knee varus-valgus loading apparatus for analysis of MRI-based intratissue strain and relaxometry

The diagnosis of early-stage osteoarthritis remains as an unmet challenge in medicine and a roadblock to evaluating the efficacy of disease-modifying treatments. Recent studies demonstrate that unique patterns of intratissue cartilage deformation under cyclic loading can serve as potential biomarkers to detect early disease pathogenesis. However, a workflow to obtain deformation, strain maps, and quantitative MRI metrics due to the loading of articular cartilage in vivo has not been fully developed. In this study, we characterize and demonstrate an apparatus that is capable of applying a varus-valgus load to the human knee in vivo within an MRI environment to enable the measurement of cartilage structure and mechanical function. The apparatus was first tested in a lab environment, then the functionality and utility of the apparatus were examined during varus loading in a clinical 3T MRI system for human imaging. We found that the device enables quantitative MRI metrics for biomechanics and relaxometry data acquisition during joint loading leading to compression of the medial knee compartment. Integration with spiral DENSE MRI during cyclic loading provided time-dependent displacement and strain maps within the tibiofemoral cartilage. The results from these procedures demonstrate that the performance of this loading apparatus meets the design criteria and enables a simple and practical workflow for future studies of clinical cohorts, and the identification and validation of imaging-based biomechanical biomarkers.

Electrical Stimulation of Mesenchymal Stem Cells as a Tool for Proliferation and Differentiation in Cartilage Tissue Engineering: A Scaffold-Based Approach

Electrical stimulation (ES) is a widely discussed topic in the field of cartilage tissue engineering due to its ability to induce chondrogenic differentiation (CD) and proliferation. It shows promise as a potential therapy for osteoarthritis (OA). In this study, we stimulated mesenchymal stem cells (MSCs) incorporated into collagen hydrogel (CH) scaffolds, consisting of approximately 500,000 cells each, for 1 h per day using a 2.5 Vpp (119 mV/mm) 8 Hz sinusoidal signal. We compared the cell count, morphology, and CD on days 4, 7, and 10. The results indicate proliferation, with an increase ranging from 1.86 to 9.5-fold, particularly on day 7. Additionally, signs of CD were observed. The stimulated cells had a higher volume, while the stimulated scaffolds showed shrinkage. In the ES groups, up-regulation of collagen type 2 and aggrecan was found. In contrast, SOX9 was up-regulated in the control group, and MMP13 showed a strong up-regulation, indicating cell stress. In addition to lower stress levels, the control groups also showed a more spheroidic shape. Overall, scaffold-based ES has the potential to achieve multiple outcomes. However, finding the appropriate stimulation pattern is crucial for achieving successful chondrogenesis.

Lactic Acid-Induced Colloidal Microrheology of Synovial Fluids

The presence of colloidal scaffolds composed of proteins and hyaluronic acid engenders unique viscous and elastic properties to the synovial fluid (SF). While the elastic resistance of SF due to the presence of such nanoscale structures provides the load-bearing capacity, the viscous nature enables fluidity of the joints during the movements to minimize the wear and tear of the adjacent muscle, cartilage, or bone tissues. It is well-known that the hypoxic conditions at the bone joints often increase the lactic acid (LA) concentration due to the occurrence of excess anaerobic respiration during either hyperactivity or arthritic conditions. The present study uncovers that in such a scenario, beyond a critical loading of LA, the colloidal nanoscaffolds of SF break down to precipitate higher molecular weight (MW) proteins and hyaluronic acid (HA). Subsequently, the viscosity and elasticity of SF reduce drastically to manifest a fluid that has reduced load bearing and wear and tear resistance capacity. Interestingly, the study also suggests that a heathy SF is a viscoelastic fluid with a mild Hookean elasticity and non-Newtonian fluidity, which eventually transforms into a viscous watery liquid in the presence of a higher loading of LA. We employ this knowledge to biosynthesize an artificial SF that emulates the characteristics of the real one. Remarkably, the spatiotemporal microscopic images uncover that even for the artificial SF, a dynamic cross-linking of the high MW proteins and HA takes place before precipitating out of the same from the artificial SF matrix, emulating the real one. Control experiments suggest that this phenomenon is absent in the case when LA is mixed with either pure HA or proteins. The experiments unfold the specific role of LA in the destruction of colloidal nanoscaffolds of synovia, which is an extremely important requirement for the biosynthesis and translation of artificial synovial fluid.

Adaptive Fusion of Deep Learning With Statistical Anatomical Knowledge for Robust Patella Segmentation From CT Images

Kneeosteoarthritis (KOA), as a leading joint disease, can be decided by examining the shapes of patella to spot potential abnormal variations. To assist doctors in the diagnosis of KOA, a robust automatic patella segmentation method is highly demanded in clinical practice. Deep learning methods, especially convolutional neural networks (CNNs) have been widely applied to medical image segmentation in recent years. Nevertheless, poor image quality and limited data still impose challenges to segmentation via CNNs. On the other hand, statistical shape models (SSMs) can generate shape priors which give anatomically reliable segmentation to varying instances. Thus, in this work, we propose an adaptive fusion framework, explicitly combining deep neural networks and anatomical knowledge from SSM for robust patella segmentation. Our adaptive fusion framework will accordingly adjust the weight of segmentation candidates in fusion based on their segmentation performance. We also propose a voxel-wise refinement strategy to make the segmentation of CNNs more anatomically correct. Extensive experiments and thorough assessment have been conducted on various mainstream CNN backbones for patella segmentation in low-data regimes, which demonstrate that our framework can be flexibly attached to a CNN model, significantly improving its performance when labeled training data are limited and input image data are of poor quality.

Automated assessment of pelvic radiographs using deep learning: A reliable diagnostic tool for pelvic malalignment

Pelvic malalignment leads to general imbalance and adversely affects leg length. Timely and accurate diagnosis of pelvic alignment in patients is crucial to prevent additional complications arising from delayed treatment. Currently, doctors typically assess pelvic alignment either manually or through radiography. This study aimed to develop and assess the validity of a deep learning-based system for automatically measuring 10 radiographic parameters necessary for diagnosing pelvic displacement using standing anteroposterior pelvic X-rays. Between March 2016 and June 2021, pelvic radiographs from 1215 patients were collected. After applying specific selection criteria, 550 pelvic radiographs were chosen for analysis. These data were utilized to develop a deep learning-based system capable of automatically measuring radiographic parameters relevant to pelvic displacement diagnosis. The system's diagnostic accuracy was evaluated by comparing automatically measured values with those assessed by a clinician using 200 radiographs selected from the initial 550. The results indicated that the system exhibited high reliability, accuracy, and reproducibility, with a Pearson correlation coefficient of ≥0.9, an intra-class correlation coefficient of ≥0.9, a mean absolute error of ≤1 cm, mean square error of ≤1 cm, and root mean square error of ≤1 cm. Moreover, the system's measurement time for a single radiograph was found to be 18 to 20 times faster than that required by a clinician for manual inspection. In conclusion, our proposed deep learning-based system effectively utilizes standing anteroposterior pelvic radiographs to precisely and consistently measure radiographic parameters essential for diagnosing pelvic displacement.

Geniposidic acid alleviates osteoarthritis progression through inhibiting inflammation and chondrocytes ferroptosis

Osteoarthritis is one of the common diseases that seriously affects the quality of life of middle-aged and elderly people worldwide. Geniposidic acid (GPA) is extracted from Eucommia ulmoides that exhibits various pharmacological effects. This study investigated the function of GPA on osteoarthritis (OA) in IL-1β-stimulated mouse chondrocytes and mouse OA model. Mouse OA model was established by destabilization of the medial meniscus (DMM) and GPA was given intraperitoneal injection. The results demonstrated that GPA could alleviate DMM-induced OA in mice. In vitro, IL-1β-induced PGE2, NO, MMP1 and MMP3 were suppressed by GPA. Furthermore, IL-1β-induced ferroptosis was inhibited by GPA, as confirmed by the inhibition of MDA, iron, and ROS, as well as the upregulation of GSH, GPX4, and Ferritin. In addition, GPA was found to increase the expression of Nrf2 and HO-1. And the inhibition of GPA on IL-1β-induced inflammation and ferroptosis were prevented by Nrf2 inhibitor. In conclusion, GPA alleviates OA progression through inhibiting inflammation and chondrocytes ferroptosis via Nrf2 signalling pathway.

Gallic acid: design of a pyrogallol-containing hydrogel and its biomedical applications

Polyphenol hydrogels have garnered widespread attention due to their excellent adhesion, antioxidant, and antibacterial properties. Gallic acid (GA) is a typical derivative of pyrogallol that is used as a hydrogel crosslinker or bioactive additive and can be used to make multifunctional hydrogels with properties superior to those of widely studied catechol hydrogels. Furthermore, compared to polymeric tannic acid, gallic acid is more suitable for chemical modification, thus broadening its range of applications. This review focuses on multifunctional hydrogels containing GA, aiming to inspire researchers in future biomaterial design. We first revealed the interaction mechanisms between GA molecules and between GA and polymers, analyzed the characteristics GA imparts to hydrogels and compared GA hydrogels with hydrogels containing catechol. Subsequently, in this paper, various methods of integrating GA into hydrogels and the applications of GA in biomedicine are discussed, finally assessing the current limitations and future development potential of GA. In summary, GA, a natural small molecule polyphenol with excellent functionality and diverse interaction modes, has great potential in the field of biomedical hydrogels.

Quality of Outcomes Research in Total Ankle Arthroplasty

Total ankle arthroplasty is a topic that has recently gained increasing interest, largely due to the improved outcomes, which have been demonstrated by short- and mid-term research studies on the newer, third-generation implant designs. The purpose of this review is to provide an updated assessment of the quality of outcomes research on total ankle arthroplasty.

Using Decellularized Magnetic Microrobots to Deliver Functional Cells for Cartilage Regeneration

The use of natural cartilage extracellular matrix (ECM) has gained widespread attention in the field of cartilage tissue engineering. However, current approaches for delivering functional scaffolds for osteoarthritis (OA) therapy rely on knee surgery, which is limited by the narrow and complex structure of the articular cavity and carries the risk of injuring surrounding tissues. This work introduces a novel cell microcarrier, magnetized cartilage ECM-derived scaffolds (M-CEDSs), which are derived from decellularized natural porcine cartilage ECM. Human bone marrow mesenchymal stem cells are selected for their therapeutic potential in OA treatments. Owing to their natural composition, M-CEDSs have a biomechanical environment similar to that of human cartilage and can efficiently load functional cells while maintaining high mobility. The cells are released spontaneously at a target location for at least 20 days. Furthermore, cell-seeded M-CEDSs show better knee joint function recovery than control groups 3 weeks after surgery in preclinical experiments, and ex vivo experiments reveal that M-CEDSs can rapidly aggregate inside tissue samples. This work demonstrates the use of decellularized microrobots for cell delivery and their in vivo therapeutic effects in preclinical tests.

Exploring the Implications of Golgi Apparatus Dysfunction in Bone Diseases

The Golgi apparatus is an organelle responsible for protein processing, sorting, and transport in cells. Recent research has shed light on its possible role in the pathogenesis of various bone diseases. This review seeks to explore its significance in osteoporosis, osteogenesis imperfecta, and other bone conditions such as dysplasias. Numerous lines of evidence demonstrate that perturbations to Golgi apparatus function can disrupt post-translational protein modification, folding and trafficking functions crucial for bone formation, mineralization, and remodeling. Abnormalities related to glycosylation, protein sorting, or vesicular transport in Golgi have been associated with altered osteoblast and osteoclast function, compromised extracellular matrix composition, as well as disrupted signaling pathways involved with homeostasis of bones. Mutations or dysregulation of Golgi-associated proteins, including golgins and coat protein complex I and coat protein complex II coat components, have also been implicated in bone diseases. Such genetic alterations may disrupt Golgi structure, membrane dynamics, and protein transport, leading to bone phenotype abnormalities. Understanding the links between Golgi apparatus dysfunction and bone diseases could provide novel insights into disease pathogenesis and potential therapeutic targets. Future research should focus on unraveling specific molecular mechanisms underlying Golgi dysfunction associated with bone diseases to develop targeted interventions for restoring normal bone homeostasis while decreasing clinical manifestations associated with these issues.

ADAM8 silencing suppresses the migration and invasion of fibroblast-like synoviocytes via FSCN1/MAPK cascade in osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a degenerative joint disease that affects elderly populations worldwide, causing pain and disability. Alteration of the fibroblast-like synoviocytes (FLSs) phenotype leads to an imbalance in the synovial inflammatory microenvironment, which accelerates the progression of OA. Despite this knowledge, the specific molecular mechanisms of the synovium that affect OA are still unclear.

METHODS

Both in vitro and in vivo experiments were undertaken to explore the role of ADAM8 playing in the synovial inflammatory of OA. A small interfering RNA (siRNA) was targeting ADAM8 to intervene. High-throughput sequencing was also used.

RESULTS

Our sequencing analysis revealed significant upregulation of the MAPK signaling cascade and ADAM8 gene expression in IL-1β-induced FLSs. The in vitro results demonstrated that ADAM8 blockade inhibited the invasion and migration of IL-1β-induced FLSs, while also suppressing the expression of related matrix metallomatrix proteinases (MMPs). Furthermore, our study revealed that inhibiting ADAM8 weakened the inflammatory protein secretion and MAPK signaling networks in FLSs. Mechanically, it revealed that inhibiting ADAM8 had a significant effect on the expression of migration-related signaling proteins, specifically FSCN1. When siADAM8 was combined with BDP-13176, a FSCN1 inhibitor, the migration and invasion of FLSs was further inhibited. These results suggest that FSCN1 is a crucial downstream factor of ADAM8 in regulating the biological phenotypes of FLSs. The in vivo experiments demonstrated that ADAM8 inhibition effectively reduced synoviocytes inflammation and alleviated the progression of OA in rats.

CONCLUSIONS

ADAM8 could be a promising therapeutic target for treating OA by targeting synovial inflammation.

Comparison of Early Complication Rates After High Tibial Osteotomy Versus Unicompartmental Knee Arthroplasty for Knee Osteoarthritis

Background

Although both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) can be utilized to treat unicompartmental osteoarthritis (OA) in select patients, the early complication rates between the 2 procedures are not well understood. Understanding of the complication profiles for both procedures would help clinicians counsel patients with unicompartmental knee OA who may be eligible for either treatment option.

Purpose

To compare the 30-day complication rates after HTO versus UKA for the treatment of knee OA using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

Study Design

Cohort study; Level of evidence, 3.

Methods

NSQIP registries between 2006 and 2019 were queried using Current Procedural Terminology codes to identify patients undergoing HTO and UKA for knee OA. Patients >60 years of age were excluded. Patient demographics, preoperative comorbidities, and intraoperative data were collected. Postoperative 30-day complications, including venous thromboembolism (VTE), urinary tract infection (UTI), transfusion, surgical-site infection (SSI), and reoperations were recorded. Complication rates between treatment groups were compared using a multivariate logistic regression model adjusted for sex, age, body mass index, steroid use, respiratory status (smoking/dyspnea/chronic obstructive pulmonary disease), diabetes, and hypertension.

Results

A total of 156 patients treated with HTO and 4755 patients treated with UKA for knee OA were identified. Mean patient ages were 46 years for the HTO group and 53.4 years for the UKA group. Operative time was significantly longer in the HTO group versus the UKA group (112 minutes vs 90 minutes; P < .001). Multivariate analyses found no significant differences in VTE (1.3% vs 0.6%), UTI (0.6% vs 0.3%), transfusion (0.6% vs 0.2%), deep SSI (0.6% vs 0.1%), and reoperation (1.3% vs 1%) rates between HTO and UKA groups. The HTO group had a higher rate of superficial SSI compared with the UKA group (2.6% vs 0.6%; P = .006) (adjusted odds ratio, 4.2; 95% CI, 1.4-12.5; P = .01).

Conclusion

There were no differences in 30-day VTE, UTI, transfusion, deep SSI, and reoperation rates for HTO versus UKA in the treatment of knee OA. HTO was associated with a higher rate of superficial SSI compared with UKA. These findings serve to guide clinicians in counseling patients regarding the early risks after HTO and UKA.

The distribution of pressure forces of the foot on the ground during gait in patients with hip osteoarthritis

BACKGROUND

Hip osteoarthritis is a major civilizational challenge of the ageing population, usually due to the reduced function of gait. In the light of this fact, gait analysis has become an important issue for the doctor, the physiotherapist and the patient, as it serves as a useful tool in diagnosis, recovery, and rehabilitation. Pedobarography is one of the most modern gait analysis methods.

OBJECTIVE

The aim of this study is to assess the distribution of pressure forces of the foot on the ground during gait in patients with hip osteoarthritis.

METHODS

Dynamic foot tests were performed by means of a two-meter RSscan® International platform, equipped with 16.384 sensors with the scanning frequency level exceeding 500 Hz. Patients were divided into two groups: the research group of N= 60 individuals with hip osteoarthritis, aged 52-84; and the control group of N= 32 individuals without hip osteoarthritis, aged 50-74. Data distribution analysis was performed with the Shapiro-Wilk test, followed by a non-parametric Mann-Whitney U test.

RESULTS

The differences between the mean results of maximal peak values of pressure and force in such areas as the big toe, metatarsal I, III, IV, V, lateral and medial heel are significantly lower in the research group than in the control group. Only in the area of metatarsal II, the mean value of pressure is higher in the research group than in the control group. For all metatarsals, the midfoot and medial heel mean results of the contact area are significantly higher in the research group than in the control group. The differences between mean load rate were also tested. The test revealed statistical significance of metatarsal II and III, and the medial heel while metatarsal II displayed a higher mean value in the research group than in the control group.

CONCLUSION

The distribution of the pressure forces of the foot can indicate imbalances which cause degenerative changes. Therefore, early detection of changes can help in prevention or delay of hip osteoarthritis in conjunction with proper therapy.

Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial

Various types of cellular injection have become a popular and costly treatment option for patients with knee osteoarthritis despite a paucity of literature establishing relative efficacy to each other or corticosteroid injections. Here we aimed to identify the safety and efficacy of cell injections from autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic human umbilical cord tissue-derived mesenchymal stromal cells, in comparison to corticosteroid injection (CSI). The study was a phase 2/3, four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients with a diagnosis of knee osteoarthritis (Kellgren-Lawrence II-IV). Participants were randomized to the three different arms with a 3:1 distribution. Arm 1: autologous bone marrow aspirate concentrate (n = 120), CSI (n = 40); arm 2: umbilical cord tissue-derived mesenchymal stromal cells (n = 120), CSI (n = 40); arm 3: stromal vascular fraction (n = 120), CSI (n = 40). The co-primary endpoints were the visual analog scale pain score and Knee injury and Osteoarthritis Outcome Score pain score at 12 months versus baseline. Analyses of our primary endpoints, with 440 patients, revealed that at 1 year post injection, none of the three orthobiologic injections was superior to another, or to the CSI control. In addition, none of the four groups showed a significant change in magnetic resonance imaging osteoarthritis score compared to baseline. No procedure-related serious adverse events were reported during the study period. In summary, this study shows that at 1 year post injection, there was no superior orthobiologic as compared to CSI for knee osteoarthritis. ClinicalTrials.gov Identifier: NCT03818737.

Patients with glenohumeral arthritis are more likely to be prescribed opioids in the emergency department or urgent care setting

OBJECTIVE

The objective is to quantify the rate of opioid and benzodiazepine prescribing for the diagnosis of shoulder osteoarthritis across a large healthcare system and to describe the impact of a clinical decision support intervention on prescribing patterns.

DESIGN

A prospective observational study.

SETTING

One large healthcare system.

PATIENTS AND PARTICIPANTS

Adult patients presenting with shoulder osteoarthritis.

INTERVENTIONS

A clinical decision support intervention that presents an alert to prescribers when patients meet criteria for increased risk of opioid use disorder.

MAIN OUTCOME MEASURE

The percentage of patients receiving an opioid or benzodiazepine, the percentage who had at least one risk factor for misuse, and the percent of encounters in which the prescribing decision was influenced by the alert were the main outcome measures.

RESULTS

A total of 5,380 outpatient encounters with a diagnosis of shoulder osteoarthritis were included. Twenty-nine percent (n = 1,548) of these encounters resulted in an opioid or benzodiazepine prescription. One-third of those who received a prescription had at least one risk factor for prescription misuse. Patients were more likely to receive opioids from the emergency department or urgent care facilities (40 percent of encounters) compared to outpatient facilities (28 percent) (p < .0001). Forty-four percent of the opioid prescriptions were for "potent opioids" (morphine milliequivalent conversion factor > 1). Of the 612 encounters triggering an alert, the prescribing decision was influenced (modified or not prescribed) in 53 encounters (8.7 percent). All but four (0.65 percent) of these encounters resulted in an opioid prescription.

CONCLUSION

Despite evidence against routine opioid use for osteoarthritis, one-third of patients with a primary diagnosis of glenohumeral osteoarthritis received an opioid prescription. Of those who received a prescription, over one-third had a risk factor for opioid misuse. An electronic clinic decision support tool influenced the prescription in less than 10 percent of encounters.

The landscape of surgical robotics in orthopedics surgery

Orthopedic surgery is one of the first surgical specialties to apply surgical robotics in clinical practice, which has become an interesting field over the years with promising results. Surgical robotics can facilitate total joint arthroplasty by providing robotic support to accurately prepare the bone, improving the ability to reproduce alignment, and restoring normal kinematics. Various robotic systems are available on the market, each tailored to specific types of surgeries and characterized by a series of features with different requirements and/or modus operandi. Here, a narrative review of the current state of surgical robotic systems for total joint knee arthroplasty is presented, covering the different categories of robots, which are classified based on the operation, requirements, and level of interaction with the surgeon. The different robotic systems include closed/open platform, image-based/imageless, and passive/active/semi-active systems. The main goal of a robotic system is to increase the accuracy and precision of the operation regardless of the type of system. Despite the short history of surgical robots, they have shown clinical effectiveness compared to conventional techniques in orthopedic surgery. When considering which robotic system to use, surgeons should carefully evaluate the different benefits and drawbacks to select the surgical robot that fits their needs the best.

Can exercise interventions reduce external knee adduction moment during gait? A systematic review and meta-analysis

BACKGROUND

An increased external knee adduction moment has been identified as a factor contributing to the progression of medial knee osteoarthritis. Interventions that reduce knee adduction moment may help prevent knee osteoarthritis onset and progression. While exercise interventions have been commonly used to treat knee osteoarthritis, whether exercises can modulate knee adduction moment in knee osteoarthritis patients remains unknown. This systematic review and meta-analysis aimed to determine if exercise interventions are effective in reducing knee adduction moment during gait.

METHODS

Study reports published through May 2023 were screened for pre-specified inclusion/exclusion criteria. Nine studies met the eligibility criteria and yielded 24 effect sizes comparing the reduction in knee adduction moment of the exercise intervention groups to the control groups. Moderator/experimental variables concerning characteristics of the exercise interventions and included subjects (e.g., sex, BMI, type of exercise, muscle group targeted, training volume, physical therapist supervision) that may contribute to variation among studies were explored through subgroup analysis and meta-regression.

FINDINGS

The effect of exercise intervention on modulating knee adduction moment during gait was no better than control (ES = -0.004, P = 0.946). Sub-group analysis revealed that the effect sizes of studies containing only females (positive exercise effect) were significantly greater than studies containing both males and females.

INTERPRETATION

Exercise may not be effective in reducing knee adduction moment during gait. Clinicians aiming to decrease knee adduction moment in patients with medial knee osteoarthritis should consider alternative treatment options. Exploring the underlying mechanism(s) regarding a more positive response to exercises in females may help design more effective exercise interventions.

Burden of knee osteoarthritis in the Middle East and North Africa (MENA): an epidemiological analysis from 1990 to 2019

BACKGROUND

Knee is the most affected joint in osteoarthritis (OA) and accounts for almost four-fifths of the burden of OA globally. We aimed to explore the prevalence, incidence, trends, and burden of knee OA during 1990-2019 in the Middle East and North Africa (MENA) region, using the Global Burden of Disease (GBD) study data.

METHODS

This is an epidemiological study based on the GBD data from 1990 to 2019 on knee OA in MENA countries. The prevalence, incidence, and years lived with disability (YLD) numbers of knee OA were obtained for both genders. Similarly, age-standardized rates of these indexes per 100,000 people and the proportion of total YLD caused by knee OA in each country and for the MENA region were evaluated.

RESULTS

The prevalence of knee osteoarthritis in the MENA region increased 2.88-fold, from 6.16 million cases to 17.75 million, between 1990 and 2019. Furthermore, in 2019, knee osteoarthritis accounted for approximately 1.69 million (95% UI 1.46-1.95) incident cases in MENA. The age-standardized prevalence was higher in women between 1990 (3.94% [95% UI 3.39-4.55] in women and 3.24% [95% UI 2.79-3.72] in men) and 2019 (4.44% [95% UI 3.83-5.10] in women and 3.66% [3.14-4.21] in men). Total YLDs due to knee osteoarthritis increased by more than 2.88-fold, rising from 196.29 thousand [95% UI 97.17-399.29] in 1990 to 564.66 thousand [95% UI 275.06-1,150.68] in 2019. In the year 2019, Kuwait, Turkey, and Oman had the highest age-standardized prevalence (4.42% [95% UI 3.79-5.08]), YLD (132.41 [95% UI 65.79-267.56] per 100 000), and increase (21.17%) in YLD compared with 1990 in MENA region, respectively.

CONCLUSION

The prevalence of and YLDs due to knee OA in MENA has escalated over the last three decades. Considering the expanding burden of knee OA in MENA, policymakers should be more concerned to implement preventive strategies.

Patient-specific Risk Factors Increase Episode of Care Costs After Lumbar Decompression

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To determine, which patient-specific risk factors increase total episode of care (EOC) costs in a population of Centers for Medicare and Medicaid Services beneficiaries undergoing lumbar decompression.

SUMMARY OF BACKGROUND DATA

Lumbar decompression is an effective option for the treatment of central canal stenosis or radiculopathy in patients unresponsive to nonoperative management. Given that elderly Americans are more likely to have one or more chronic medical conditions, there is a need to determine, which, if any, patient-specific risk factors increase health care costs after lumbar decompression.

METHODS

Care episodes limited to lumbar decompression surgeries were retrospectively reviewed on a Centers for Medicare and Medicaid Service reimbursement database at our academic institution between 2014 and 2019. The 90-day total EOC reimbursement payments were collected. Patient electronic medical records were then matched to the selected care episodes for the collection of patient demographics, medical comorbidities, surgical characteristics, and clinical outcomes. A stepwise multivariate linear regression model was developed to predict patient-specific risk factors that increased total EOC costs after lumbar decompression. Significance was set at P <0.05.

RESULTS

A total of 226 patients were included for analysis. Risk factors associated with increased total EOC cost included increased age (per year) (β = $324.70, P < 0.001), comorbid depression (β = $4368.30, P = 0.037), revision procedures (β = $6538.43, P =0.012), increased hospital length of stay (per day) (β = $2995.43, P < 0.001), discharge to an inpatient rehabilitation facility (β = $14,417.42, P = 0.001), incidence of a complication (β = $8178.07, P < 0.001), and readmission (β = $18,734.24, P < 0.001) within 90 days.

CONCLUSIONS

Increased age, comorbid depression, revision decompression procedures, increased hospital length of stay, discharge to an inpatient rehabilitation facility, and incidence of a complication and readmission within 90 days were all associated with increased total episodes of care costs.

Therapeutic potential of senolytic agent quercetin in osteoarthritis: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Quercetin, a natural flavonoid, has shown promise as a senolytic agent for various degenerative diseases. Recently, its protective effect against osteoarthritis (OA), a representative age-related disease of the musculoskeletal system, has attracted much attention. The aim of this study is to summarize and analyze the current literature on the effects of quercetin on OA cartilage in in vivo preclinical studies.

METHODS

The Medline (via/using PubMed), Embase, and Web of Science databases were searched up to March 10th, 2023. Risk of bias and the qualitative assessment including mechanisms of all eligible studies and a meta-analysis of cartilage histological scores among the applicable studies was performed.

RESULTS

A total of 12 in vivo animal studies were included in this systematic review. A random-effects meta-analysis was performed on six studies using the Osteoarthritis Research Society International (OARSI) scoring system, revealing that quercetin significantly improved OA cartilage OARSI scores (SMD, -6.30 [95% CI, -9.59 to -3.01]; P = 0.0002; heterogeneity: I2 = 86%). The remaining six studies all supported quercetin's protective effects against OA during disease and aging.

CONCLUSIONS

Quercetin has shown beneficial effects on cartilage during OA across animal species. Future double-blind randomized controlled clinical trials are needed to verify the efficacy of quercetin in the treatment of OA in humans.

Validation of a Robotic Testbench for Evaluating Biomechanical Effects of Implant Rotation in Total Knee Arthroplasty on a Cadaveric Specimen

In this study, we developed and validated a robotic testbench to investigate the biomechanical compatibility of three total knee arthroplasty (TKA) configurations under different loading conditions, including varus-valgus and internal-external loading across defined flexion angles. The testbench captured force-torque data, position, and quaternion information of the knee joint. A cadaver study was conducted, encompassing a native knee joint assessment and successive TKA testing, featuring femoral component rotations at -5°, 0°, and +5° relative to the transepicondylar axis of the femur. The native knee showed enhanced stability in varus-valgus loading, with the +5° external rotation TKA displaying the smallest deviation, indicating biomechanical compatibility. The robotic testbench consistently demonstrated high precision across all loading conditions. The findings demonstrated that the TKA configuration with a +5° external rotation displayed the minimal mean deviation under internal-external loading, indicating superior joint stability. These results contribute meaningful understanding regarding the influence of different TKA configurations on knee joint biomechanics, potentially influencing surgical planning and implant positioning. We are making the collected dataset available for further biomechanical model development and plan to explore the 6 Degrees of Freedom (DOF) robotic platform for additional biomechanical analysis. This study highlights the versatility and usefulness of the robotic testbench as an instrumental tool for expanding our understanding of knee joint biomechanics.

Multifunctional hydrogels: advanced therapeutic tools for osteochondral regeneration

Various joint pathologies such as osteochondritis dissecans, osteonecrosis, rheumatic disease, and trauma, may result in severe damage of articular cartilage and other joint structures, ranging from focal defects to osteoarthritis (OA). The osteochondral unit is one of the critical actors in this pathophysiological process. New approaches and applications in tissue engineering and regenerative medicine continue to drive the development of OA treatment. Hydrogel scaffolds, a component of tissue engineering, play an indispensable role in osteochondral regeneration. In this review, tissue engineering strategies regarding osteochondral regeneration were highlighted and summarized. The application of hydrogels for osteochondral regeneration within the last five years was evaluated with an emphasis on functionalized physical and chemical properties of hydrogel scaffolds, functionalized delivery hydrogel scaffolds as well as functionalized intelligent response hydrogel scaffolds. Lastly, to serve as guidance for future efforts in the creation of bioinspired hydrogel scaffolds, a succinct summary and new views for specific mechanisms, applications, and existing limitations of the newly designed functionalized hydrogel scaffolds were offered.

Republication of "Perspectives in Treatments of End-Stage Ankle Arthritis Among Orthopaedic Surgeons: Analysis of an American Orthopaedic Foot & Ankle Society (AOFAS) Member Survey"

Background

This study aimed to assess the preferred operative treatment for patients over the age of 60 with end-stage ankle arthritis and perspectives on total ankle replacement (TAR) among American Orthopaedic Foot & Ankle Society (AOFAS) members. Associated factors were analyzed for potential contraindications among members with different levels of experience.

Method

A questionnaire containing 6 questions was designed and sent to 2056 members of the AOFAS. Responses were received from 467 orthopaedic surgeons practicing in the United States (76%), Canada (5%), and 26 other countries (20%). Participants were grouped for response comparisons according to country as well as experience level. Differences in contraindications were compared using χ2 tests or exact tests.

Results

Respondents practicing in the United States and surgeons who perform 11 or more TARs per year tended to recommend operative treatments favoring TAR and displayed recognition of its increasing role (P < .05). Overall, respondents felt that 41% of typical patients over 60 years old with end-stage arthritis would be best treated with TAR. Talus avascular necrosis, morbid obesity (body mass index >40 kg/m2), and poorly controlled diabetes with neuropathy were most recognized as the absolute contraindications to TAR. Surgeon's experience affected the consideration of these clinical factors as contraindications.

Conclusions

Total ankle replacement has a substantial and increasing role in the treatment of end-stage ankle arthritis in patients over the age of 60. Absolute and potential contraindications of the procedures were indicated from a cross-sectional survey of AOFAS members. Surgeons more experienced with total ankle replacement felt more comfortable employing it in a wider range of clinical settings.

Level of Evidence

Level III, therapeutic.

Knockdown of mechanosensitive adaptor Hic-5 ameliorates post-traumatic osteoarthritis in rats through repression of MMP-13

Osteoarthritis (OA) is the most common joint disease associated with articular cartilage destruction. Matrix metalloproteinase-13 (MMP-13) has an essential role in OA pathogenesis by degradation of collagen II, a major component of articular cartilage. Hydrogen peroxide-inducible clone-5 (Hic-5; TGFB1I1), a transforming growth factor-β-inducible mechanosensor, has previously been reported to promote OA pathogenesis by upregulating MMP-13 expression in mouse osteoarthritic lesions. In our current study, immunohistochemical analysis showed that Hic-5 protein expression was increased in human OA cartilage compared with normal cartilage. Functional experiments demonstrated that Hic-5 and MMP-13 expression was increased by mechanical stress, and mechanical stress-induced MMP-13 expression was suppressed by Hic-5 siRNA in human chondrocytes. Moreover, intracellular localization of Hic-5 shifted to the nucleus from focal adhesions in human chondrocytes subjected to mechanical stress, and nuclear Hic-5 increased MMP-13 gene expression. In vivo, intra-articular injection of Hic-5 siRNA decreased the Osteoarthritis Research Society International score and MMP-13 protein expression in articular cartilage of OA rats. Our findings suggest that Hic-5 regulates transcription of MMP-13 in human chondrocytes, and Hic-5 may be a novel therapeutic target for OA because OA progression was suppressed by intra-articular injection of Hic-5 siRNA in rats.

Comparison of conventional socket attachment and bone-anchored prosthesis for persons living with transfemoral amputation - mobility and quality of life

BACKGROUND

For patients with transfemoral amputation experiencing issues with their sockets, bone-anchored prosthesis systems are an alternative and sometimes the only way to be mobile and independent. The present cross-sectional study aimed to investigate the gait performance and quality of life of a group of patients treated with bone-anchored systems compared to those of participants treated with a conventional socket-suspended prosthesis.

METHODS

A total of 17 participants with a socket-suspended and 20 with a bone-anchored prosthesis were included. Gait patterns were examined for symmetry, and performance was assessed using the six-minute walk test and the timed "Up & Go" test. Magnetic resonance imaging was performed to detect signs of osteoarthritis in both hips. Mobility in everyday life and quality of life were assessed using questionnaires.

FINDINGS

There were no differences between the groups regarding the quality of life, daily mobility, and gait performance. The step width was significantly higher for the patients using socket-suspended prosthesis. The socket-suspended group showed a significant asymmetry regarding the step length. In the socket-suspended group, the prosthetic leg showed significantly higher cartilage abrasion than the contralateral leg did.

INTERPRETATION

Large differences in the measured outcomes in both groups illustrate the very different capabilities of the individual participants, which is apparently not primarily determined by the type of treatment. For patients who are satisfied with the socket treatment and perform well, bone-anchored prosthesis systems may not necessarily improve their functional capabilities and perceived quality of life.

Warm needle acupuncture for osteoarthritis: An overview of systematic reviews and meta-analysis

Background

Osteoarthritis (OA) is a chronic disease that is a major cause of pain and functional disability. Warm needle acupuncture (WA) therapy has been widely used to treat OA. This overview summarizes the evidence from systematic reviews (SRs) and assesses the methodological quality of previous SRs that evaluated the use of WA therapy for OA.

Methods

We searched electronic databases to identify SRs that evaluated the efficacy of WA therapy for OA. Two reviewers independently extracted data and assessed the methodological quality of the reviews according to the A Measurement Tool to Assess Systematic Reviews (AMSTAR 2) tool. The reporting quality was assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 (PRISMA 2020) guidelines. The quality of evidence was assessed according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Results

Fifteen SRs were included in this study. WA therapy was more effective than control conditions for the treatment of OA. The results of the AMSTAR 2 tool showed that the methodological quality of all included studies was critically low. The items with the lowest scores were item 2 (reporting the protocol), item 7 (listing excluded studies and justifying the exclusions), and item 16 (including conflicts of interest). Regarding the PRISMA guidelines, 2 SRs exhibited greater than 85% compliance. The overall quality of evidence in the included SRs ranged from "very low" to "moderate."

Conclusion

This overview shows that WA therapy was more effective than the control treatment for OA. However, the methodological quality of the reviews was low, indicating the need for improvements in the collection of evidence. Future studies are needed to collect high-quality evidence regarding the use of WA for OA.

Systematic review registration

https://www.researchregistry.com/, Research Registry (reviewregistry1317).

Prognostic Factors Related to Clinical Response in 210 Knees Treated by Platelet-Rich Plasma for Osteoarthritis

Many studies have shown the effectiveness of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis. We aimed to determine the factors associated with good or poor response to PRP injections in knee osteoarthritis. This was a prospective observational study. Patients with knee osteoarthritis were recruited from a university hospital. PRP was injected twice at a one-month interval. Pain was assessed on a visual analog scale (VAS) and function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic stage was collected and defined according to the Kellgren-Lawrence classification. Patients were classified as responders if they met the OMERACT-OARSI criteria at 7 months. We included 210 knees. At 7 months, 43.8% were classified as responders. Total WOMAC and VAS were significantly improved between M0 and M7. Physical therapy and a heel-buttock distance >35 cm were the two criteria associated with poor response at M7 by multivariate analysis. Pain VAS at M7 appeared to be lower in patients with osteoarthritis for less than 24 months. No adverse effects were reported. PRP treatment in knee osteoarthritis appears to be well-tolerated and effective, even in patients who reacted poorly to hyaluronic acid. Response was not associated with radiographic stage.

The Impact of Asymptomatic Human Immunodeficiency Virus-Positive Disease Status on Inpatient Complications Following Spine Surgery: A Propensity Score-Matched Analysis

In the United States, nearly 1.2 million people > 12 years old have human immunodeficiency virus (HIV), which is associated with postoperative complications following orthopedic procedures. Little is known about how asymptomatic HIV (AHIV) patients fare postoperatively. This study compares complications after common spine surgeries between patients with and without AHIV. The Nationwide Inpatient Sample (NIS) was retrospectively reviewed from 2005-2013, identifying patients aged > 18 years who underwent 2-3-level anterior cervical discectomy and fusion (ACDF), ≥4-level thoracolumbar fusion (TLF), or 2-3-level lumbar fusion (LF). Patients with AHIV and without HIV were 1:1 propensity score-matched. Univariate analysis and multivariable binary logistic regression were performed to assess associations between HIV status and outcomes by cohort. 2-3-level ACDF (n = 594 total patients) and ≥4-level TLF (n = 86 total patients) cohorts demonstrated comparable length of stay (LOS), rates of wound-related, implant-related, medical, surgical, and overall complications between AHIV and controls. 2-3-level LF (n = 570 total patients) cohorts had comparable LOS, implant-related, medical, surgical, and overall complications. AHIV patients experienced higher postoperative respiratory complications (4.3% vs. 0.4%,). AHIV was not associated with higher risks of medical, surgical, or overall inpatient postoperative complications following most spine surgical procedures. The results suggest the postoperative course may be improved in patients with baseline control of HIV infection.

Association of macronutrients intake distribution with osteoarthritis risk among adults in NHANES, 2013-2016

The association between dietary macronutrient distribution and the risk of OA remains unknown. We aimed to evaluate how dietary macronutrient distribution was correlated with the risk of OA in US adults. We performed a cross-sectional study consisting of 7,725 participants from National Health and Nutrition Examination Survey (NHANES) 2013-2016. Dietary macronutrient intake and OA status were assessed by using dietary recall method and self-reported questionnaire, respectively. We evaluated the association between dietary macronutrient distribution and the risk of OA using multivariate regression models. We conducted the isocaloric substitution analysis using the multivariate nutrient density method. Higher percentage of energy intake from fat was associated with higher risk of OA [OR = 1.05 (95% CI, 1.00, 1.09); P = 0.034]. No significant correlation was observed between the percentage of energy intake from carbohydrate or protein and risk of OA. Isocaloric substitution analysis revealed that only the substitution between fat and carbohydrate was significantly associated with the risk of OA [OR = 1.05 (95% CI, 1.003 to 1.09); P = 0.037]. Our findings suggested that a diet with low percentage of energy intake from fat may be beneficial in the prevention of OA. Further prospective cohort studies are needed to assess our results.

Effectiveness and safety of manual therapy for knee osteoarthritis: An overview of systematic reviews and meta-analyses

Background

Manual therapy has been used as an alternative approach to treat knee osteoarthritis (KOA) for many years. Numerous systematic reviews (SRs) or meta-analyses (MAs) were published to evaluate its effectiveness and safety. Nevertheless, the conclusions of SRs/MAs are inconsistent, and the uneven quality needs to be critically appraised.

Objectives

To conduct a comprehensive overview of the effectiveness and safety of manual therapy for KOA and the quality of relevant SRs/MAs, thus providing critical evidence and valuable direction for future researchers to promote the generation of advanced evidence.

Methods

The pre-defined search strategies were applied to eight electronic databases from inception to September 2022. Suitable SRs/MAs were included in accordance with the inclusion and exclusion criteria. The methodological quality, risk of bias, reporting quality, and evidence quality were assessed by two independent reviewers who used respectively the A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR-2), the Risk of Bias in Systematic Reviews (ROBIS), the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 Version (PRISMA 2020), and Grades of Recommendations, Assessment, Development and Evaluation (GRADE) based on the method of narrative synthesis. We excluded the overlapping randomized controlled trials (RCTs) and performed a re-meta-analysis of the total effective rate.

Results

A total of eleven relevant SRs/MAs were included: nine SRs/MAs were rated critically low quality, and two were rated low quality by AMSTAR-2. According to ROBIS, all SRs/MAs were rated low risk in Phase 1 (assessing relevance) and Domain 1 (study eligibility criteria) of Phase 2. Three SRs/MAs (27.27%) were rated low risk in Domain 2 (identification and selection of studies). Ten SRs/MAs (90.91%) were rated low risk in Domain 3 (data collection and study appraisal). Five SRs/MAs (45.45%) were rated low risk in Domain 4 (synthesis and findings). And five SRs/MAs (45.45%) were rated low risk in Phase 3 (risk of bias in the review). By PRISMA 2020, there were some reporting deficiencies in the aspects of abstract (2/11, 18.18%), search strategy (0/11, 0%), preprocessing of merging data (0/11, 0%), heterogeneity exploration (6/11, 54.55%), sensitivity analysis (4/11, 36.36%), publication bias (5/11, 45.45%), evidence quality (3/11, 27.27%), the list of excluded references (3/11, 27.27%), protocol and registration (1/11, 9.09%), funding (1/11, 9.09%), conflict of interest (3/11, 27.27%), and approach to relevant information (0/11, 0%). In GRADE, the evidence quality was defined as moderate quality (8 items, 21.05%), low quality (16 items, 42.11%), and critically low quality (14 items, 36.84%). Among the downgraded factors, risk of bias, inconsistency, imprecision, and publication bias were the main factors. A re-meta-analysis revealed that manual therapy can increase the total effective rate in KOA patients (risk ratio = 1.15, 95% confidence interval [1.12, 1.18], p < 0.00001; I² = 0, p = 0.84). There are four reviews that narratively report adverse effects, and no severe adverse reactions occurred in the manual therapy group.

Conclusions

Manual therapy may be clinically effective and safe for patients with KOA. However, this conclusion must be interpreted with caution because of the generally unsatisfactory study quality and inconsistent conclusions of the included SRs/MAs. Further rigorous and normative SRs/MAs are expected to be carried out to provide robust evidence for definitive conclusions.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier: CRD42022364672.

Combinatorial Effect of Mesenchymal Stem Cells and Extracellular Vesicles in a Hydrogel on Cartilage Regeneration

BACKGROUND

Mesenchymal stem cells (MSCs) are used for tissue regeneration due to their wide differentiation capacity and anti-inflammatory effects. Extracellular vesicles (EVs) derived from MSCs are also known for their regenerative effects as they contain nucleic acids, proteins, lipids, and cytokines similar to those of parental cells. There are several studies on the use of MSCs or EVs for tissue regeneration. However, the combinatorial effect of human MSCs (hMSCs) and EVs is not clear. In this study, we investigated the combinatorial effect of hMSCs and EVs on cartilage regeneration via co-encapsulation in a hyaluronic-acid (HA)-based hydrogel.

METHODS

A methacrylic-acid-based HA hydrogel was prepared to encapsulate hMSCs and EVs in hydrogels. Through in vitro and in vivo analyses, we investigated the chondrogenic potential of the HA hydrogel-encapsulated with hMSCs and EVs.

RESULTS

Co-encapsulation of hMSCs with EVs in the HA hydrogel increased the chondrogenic differentiation of hMSCs and regeneration of damaged cartilage tissue compared with that of the HA hydrogel loaded with hMSCs only.

CONCLUSION

Co-encapsulation of hMSCs and EVs in the HA hydrogel effectively enhances cartilage tissue regeneration due to the combinatorial therapeutic effect of hMSCs and EVs. Thus, in addition to cartilage tissue regeneration for the treatment of osteoarthritis, this approach would be a useful strategy to improve other types of tissue regeneration.

The talar body prosthesis treated end-stage ankle arthritis with talar body deficient: a 6-13 years of follow-up outcomes and 6-year survivorship

INTRODUCTION

Talar body deficient provides a unique challenge for ankle arthritis treatment. We studied the clinical-radiographic outcomes at 6 to 13 years and 6 year prosthesis survivorship of patients treated for ankle arthritis with poor talar body bone stock using a talar body prosthesis (TBP).

MATERIALS AND METHODS

Between 2008 and 2015, we treated 32 consecutive end-stage ankle arthritis patients with talar body deficiency by TBP implantation and fascia interposition. One patient was excluded with a diagnosis of inflammatory arthritis. We assessed visual analogue scale (VAS) of ankle pain, sagittal range of motion, American Orthopaedics Foot and Ankle Society (AOFAS) ankle-hindfoot score, Foot Ankle Ability Measure (FAAM) of activity daily living (ADL), prosthesis tibiotalar surface angle, radiographic prosthesis loosening, adjacent joint arthritis and complication. Pre-operative to last follow-up outcomes (at 6-13 years) were compared. Prosthesis survivorship was analyzed at 6 year follow-up. p < 0.05 was considered a significant difference.

RESULTS

There was statistically significant improvement of median VAS ankle pain, as 8.0 (IQR 1.0) to 1.0 (IQR 2.0), AOFAS ankle-hindfoot score from 48 (IQR 21) to 80 (IQR 7.0), FAAM of ADL from50.0 (28.0) to 88.0 (IQR 15.0), and sagittal ROM from 20^o (IQR 19°) to 33° (IQR 14°), p < 0.05. The median tibiotalar surface angle was statistically significant improved from 85.0° (IQR 8.0°) to 89.0° (IQR 3.0°), p < 0.001. No radiographic prosthesis loosening or adjacent talonavicular-calcaneocuboid joint arthritis. The 6 year prosthesis survivorship was 93.5% (95% CI 84.9-100.0%). End of survivorship was observed in 2 patients due to progressive valgus tilting at 16° and 18°, respectively. No prosthesis was revised.

CONCLUSIONS

TBP implantation with fascia replacing the articular end of distal tibia provided significant better pre- to post-operative clinical outcomes and had 6 year survivorship as 93.5% for the treatment of ankle arthritis with talar body deficient.

LEVEL OF EVIDENCE

IV.

Reconstructive Surgery and Joint-Sparing Surgery in Valgus and Varus Ankle Deformities: A Comprehensive Review

Osteoarthritis (OA) of the ankle affects about 1% of the world’s adult population, causing an important impact on patient lives and health systems. Most patients with ankle OA can show an asymmetrical wear pattern with a predominant degeneration of the medial or the lateral portion of the joint. To avoid more invasive ankle joint sacrificing procedures, joint realignment surgery has been developed to restore the anatomy of the joints with asymmetric early OA and to improve the joint biomechanics and symptoms of the patients. This narrative, comprehensive, all-embracing review of the literature has the aim to describe the current concepts of joint preserving and reconstructive surgery in the treatment of the valgus and varus ankle early OA, through an original iconography and clear indications and technical notes.

Post-traumatic knee osteoarthritis; the role of inflammation and hemarthrosis on disease progression

Knee injuries such as anterior cruciate ligament ruptures and meniscal injury are common and are most frequently sustained by young and active individuals. Knee injuries will lead to post-traumatic osteoarthritis (PTOA) in 25–50% of patients. Mechanical processes where historically believed to cause cartilage breakdown in PTOA patients. But there is increasing evidence suggesting a key role for inflammation in PTOA development. Inflammation in PTOA might be aggravated by hemarthrosis which frequently occurs in injured knees. Whereas mechanical symptoms (joint instability and locking of the knee) can be successfully treated by surgery, there still is an unmet need for anti-inflammatory therapies that prevent PTOA progression. In order to develop anti-inflammatory therapies for PTOA, more knowledge about the exact pathophysiological mechanisms and exact course of post-traumatic inflammation is needed to determine possible targets and timing of future therapies.

Cadaveric Gait Simulation of the Effect of Subtalar Arthrodesis on Total Ankle Replacement Kinematics

BACKGROUND

Patients undergoing total ankle replacement (TAR) often have symptomatic adjacent joint arthritis and deformity. Subtalar arthrodesis can effectively address a degenerative and/or malaligned hindfoot, but there is concern that it places abnormal stresses on the TAR and adjacent joints of the foot, potentially leading to early TAR failure. This study hypothesized that ankle and talonavicular joint kinematics would be altered after subtalar arthrodesis in the setting of TAR.

METHODS

Thirteen mid-tibia cadaveric specimens with neutral alignment were tested in a robotic gait simulator. To simulate gait, each specimen was secured to a static mounting fixture about a 6-degree of freedom robotic platform, and a force plate moves relative to the stationary specimen based on standardized gait parameters. Specimens were tested sequentially in TAR and TAR with subtalar arthrodesis (TAR-ST_fuse). Kinematics and range of motion of the ankle and talonavicular joint were compared between TAR and TAR-ST_fuse.

RESULTS

There were significant differences in kinematics and range of motion between TAR and TAR-ST_fuse groups. At the ankle joint, TAR-ST_fuse had less internal rotation in early-mid stance (P < .05), with decreased range of motion in the sagittal (-2.7 degrees, P = .008) and axial (-1.8 degrees, P = .002) planes in early stance, and increased range of motion in the coronal plane in middle (+1.2 degrees, P < .001) and late (+2.5 degrees, P = .012) stance. At the talonavicular joint, there were significant differences in axial and coronal kinematics in early and late stance (P < .05). Subtalar arthrodesis resulted in significantly decreased talonavicular range of motion in all planes in early and late stance (P < .003).

CONCLUSION

In ankles implanted with the TAR design used in this study, kinematics of the ankle and talonavicular joint were found to be altered after subtalar arthrodesis. Aberrant motion may reflect altered contact mechanics at the prosthesis and increased stress at the bone-implant interface, and affect the progression of adjacent joint arthritis in the talonavicular joint.

CLINICAL RELEVANCE

These findings may provide a correlate to clinical studies that have cited hindfoot arthrodesis as a risk factor for TAR failure.

Shoulder structure and function: The impact of osteoarthritis and rehabilitation strategies

STUDY DESIGN

Invited review.

BACKGROUND

Shoulder osteoarthritis can result in significant functional deficits. To improve diagnosis and treatment, we must better understand the impact of osteoarthritis on shoulder biomechanics and the known mechanical benefits of currently available treatments.

PURPOSE

The purpose of this paper is to present up-to-date data on the effects of osteoarthritis and rehabilitation on the biomechanical parameters contributing to shoulder function. With this goal, we also reviewed the anatomy and the ranges of motion of the shoulder.

METHODS

A search of electronic databases was conducted. All study designs were included to inform this qualitative, narrative literature review.

RESULTS

This review describes the biomechanics of the shoulder, the impact of osteoarthritis on shoulder function, and the treatment of shoulder osteoarthritis with an emphasis on rehabilitation.

CONCLUSIONS

The shoulder is important for the completion of activities of daily living, and osteoarthritis of the shoulder can significantly reduce shoulder motion and arm function. Although shoulder rehabilitation is an integral treatment modality to improve pain and function in shoulder osteoarthritis, few high-quality studies have investigated the effects and benefits of shoulder physical and occupational therapies. To advance the fields of therapy and rehabilitation, future studies investigating the effects of therapy intensity, therapy duration, and the relative benefits of therapy subtypes on shoulder biomechanics and function are necessary.

A three-dimensional (3D), serum-free, Collagen Type I system for chondrogenesis of canine bone marrow-derived multipotent stromal cells (cMSCs)

The dog is an underrepresented large animal translational model for orthopedic cell-based tissue engineering. While chondrogenic differentiation of canine multipotent stromal cells (cMSCs) has been reported using the classic micromass technique, cMSCs respond inconsistently to this method. The objectives of this study were to develop a three-dimensional (3D), serum-free, Collagen Type I system to facilitate cMSC chondrogenesis and, once established, to determine the effect of chondrogenic growth factors on cMSC chondrogenesis. Canine MSCs were polymerized in 100 μL Collagen Type I gels (5 mg/mL) at 1 x 10⁶ cells/construct. Constructs were assessed using morphometry, live/dead staining, and histology in 10 various chondrogenic media. Four media were selected for additional in-depth analyses via lactate dehydrogenase release, total glycosaminoglycan content, qPCR (COL1A1, COL2A, SOX9, ACAN, BGLAP and SP7), immunofluorescence, and TUNEL staining. In the presence of dexamethasone and transforming growth factor-β3 (TGF-β3), both bone morphogenic protein-2 (BMP-2) and basic fibroblast growth factor (bFGF) generated larger chondrogenic constructs, although BMP-2 was required to achieve histologic characteristics of chondrocytes. Chondrogenic medium containing dexamethasone, TGF-β3, BMP-2 and bFGF led to a significant decrease in lactate dehydrogenase release at day 3 and glycosaminoglycan content was significantly increased in these constructs at day 3, 10, and 21. Both osteogenic and chondrogenic transcripts were induced in response to dexamethasone, TGF-β3, BMP-2 and bFGF. Collagen Type II and X were detected in all groups via immunofluorescence. Finally, TUNEL staining was positive in constructs lacking BMP-2 or bFGF. In conclusion, the 3D, serum-free, Collagen Type-I assay described herein proved useful in assessing cMSC differentiation and will serve as a productive system to characterize cMSCs or to fabricate tissue engineering constructs for clinical use.

Long-Term Survival of HINTEGRA Total Ankle Replacement in 683 Patients: A Concise 20-Year Follow-up of a Previous Report

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Midterm Survivorship of the INBONE II Total Ankle Arthroplasty

BACKGROUND

The use of total ankle arthroplasty (TAA) in the treatment of ankle arthritis has grown substantially as advancements are made in design and surgical technique. Among the criteria guiding the choice between arthroplasty and arthrodesis, the long-term survival and postoperative outcomes are of crucial importance. Although outcomes of the INBONE I have been published, there is limited midterm survival data for the INBONE II. The purpose of this study was to determine the radiographic and patient-reported outcomes, and survivorship of this prosthesis in patients with a minimum 5-year follow-up.

METHODS

We retrospectively identified 51 ankles (46 patients) from 2010 to 2015 who underwent TAA with the INBONE II prosthesis at our institution. Of these, 44 cases had minimum clinical follow-up of 5 years (mean, 6.4; range 5-9). Median age was 66 years (range 42-81) and median BMI was 27.5 (range 20.1-33.0). A chart review was performed to record the incidence of revision and reoperation. Preoperative and postoperative radiographs were analyzed to assess the coronal tibiotalar alignment (TTA), the talar inclination angle, and the presence of periprosthetic lucencies and cyst formation. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared. Survivorship was determined by incidence of revision, defined as removal of a metallic component.

RESULTS

The survivorship at 5 years was 98% and the rate of reoperation was 7.8% (n = 4); 2 patients underwent irrigation and debridement for infection, 1 patient underwent a medializing calcaneal osteotomy, and 1 patient underwent open gutter debridement, 1 patient underwent a revision of a subsided talar component at 3.2 years after index surgery. Average postoperative TTA was 88.6 degrees, with 42 rated as neutral (85-95 degrees), 2 varus (<85 degrees), and no valgus (>95 degrees) ankles. At final follow-up, asymptomatic periprosthetic cysts were observed in 8 patients. All FAOS domain scores improved between preoperative and final follow-up.

CONCLUSION

At midterm follow-up, we observed significant improvement in radiographic alignment and patient-reported outcome scores for the INBONE II total ankle prosthesis. In addition, this cohort has had a relatively low reoperation rate and high survivorship.

LEVEL OF EVIDENCE

Level IV, case series.

Knee Joint Menisci Are Shock Absorbers: A Biomechanical In-Vitro Study on Porcine Stifle Joints

The aim of this biomechanical in vitro study was to answer the question whether the meniscus acts as a shock absorber in the knee joint or not. The soft tissue of fourteen porcine knee joints was removed, leaving the capsuloligamentous structures intact. The joints were mounted in 45° neutral knee flexion in a previously validated droptower setup. Six joints were exposed to an impact load of 3.54 J, and the resultant loss factor (η) was calculated. Then, the setup was modified to allow sinusoidal loading under dynamic mechanical analysis (DMA) conditions. The remaining eight knee joints were exposed to 10 frequencies ranging from 0.1 to 5 Hz at a static load of 1210 N and a superimposed sinusoidal load of 910 N (2.12 times body weight). Forces (F) and deformation (l) were continuously recorded, and the loss factor (tan δ) was calculated. For both experiments, four meniscus states (intact, medial posterior root avulsion, medial meniscectomy, and total lateral and medial meniscectomy) were investigated. During the droptower experiments, the intact state indicated a loss factor of η = 0.1. Except for the root avulsion state (−15%, p = 0.12), the loss factor decreased (p &lt; 0.046) up to 68% for the total meniscectomy state (p = 0.028) when compared to the intact state. Sinusoidal DMA testing revealed that knees with an intact meniscus had the highest loss factors, ranging from 0.10 to 0.15. Any surgical manipulation lowered the damping ability: Medial meniscectomy resulted in a reduction of 24%, while the resection of both menisci lowered tan δ by 18% compared to the intact state. This biomechanical in vitro study indicates that the shock-absorbing ability of a knee joint is lower when meniscal tissue is resected. In other words, the meniscus contributes to the shock absorption of the knee joint not only during impact loads, but also during sinusoidal loads. The findings may have an impact on the rehabilitation of young, meniscectomized patients who want to return to sports. Consequently, such patients are exposed to critical loads on the articular cartilage, especially when performing sports with recurring impact loads transmitted through the knee joint surfaces.