Adipokines induce catabolism of newly synthesized matrix in cartilage and meniscus tissues

Anterior Cruciate Ligament Reconstruction With Concomitant Meniscal Repair: Is Graft Choice Predictive of Meniscal Repair Success?

Background

When meniscal repair is performed during anterior cruciate ligament (ACL) reconstruction (ACLR), the effect of ACL graft type on meniscal repair outcomes is unclear.

Hypothesis

The authors hypothesized that meniscal repairs would fail at the lowest rate when concomitant ACLR was performed with bone--patellar tendon--bone (BTB) autograft.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent meniscal repair at primary ACLR were identified from a longitudinal, prospective cohort. Meniscal repair failures, defined as any subsequent surgical procedure addressing the meniscus, were identified. A logistic regression model was built to assess the association of graft type, patient-specific factors, baseline Marx activity rating score, and meniscal repair location (medial or lateral) with repair failure at 6-year follow-up.

Results

A total of 646 patients were included. Grafts used included BTB autograft (55.7%), soft tissue autograft (33.9%), and various allografts (10.4%). We identified 101 patients (15.6%) with a documented meniscal repair failure. Failure occurred in 74 of 420 (17.6%) isolated medial meniscal repairs, 15 of 187 (8%) isolated lateral meniscal repairs, and 12 of 39 (30.7%) of combined medial and lateral meniscal repairs. Meniscal repair failure occurred in 13.9% of patients with BTB autografts, 17.4% of patients with soft tissue autografts, and 19.4% of patients with allografts. The odds of failure within 6 years of index surgery were increased more than 2-fold with allograft versus BTB autograft (odds ratio = 2.34 [95% confidence interval, 1.12-4.92]; P = .02). There was a trend toward increased meniscal repair failures with soft tissue versus BTB autografts (odds ratio = 1.41 [95% confidence interval, 0.87-2.30]; P = .17). The odds of failure were 68% higher with medial versus lateral repairs (P < .001). There was a significant relationship between baseline Marx activity level and the risk of subsequent meniscal repair failure; patients with either very low (0-1 points) or very high (15-16 points) baseline activity levels were at the highest risk (P = .004).

Conclusion

Meniscal repair location (medial vs lateral) and baseline activity level were the main drivers of meniscal repair outcomes. Graft type was ranked third, demonstrating that meniscal repairs performed with allograft were 2.3 times more likely to fail compared with BTB autograft. There was no significant difference in failure rates between BTB versus soft tissue autografts.

Registration

NCT00463099 (ClinicalTrials.gov identifier).

The Influence of Obesity and Meniscal Coverage on In Vivo Tibial Cartilage Thickness and Strain

Background

Obesity, which potentially increases loading at the knee, is a common and modifiable risk factor for the development of knee osteoarthritis. The menisci play an important role in distributing joint loads to the underlying cartilage. However, the influence of obesity on the role of the menisci in cartilage load distribution in vivo is currently unknown.

Purpose

To measure tibial cartilage thickness and compressive strain in response to walking in areas covered and uncovered by the menisci in participants with normal body mass index (BMI) and participants with high BMI.

Study Design

Controlled laboratory study.

Methods

Magnetic resonance (MR) images of the right knees of participants with normal BMI (<25 kg/m²; n = 8) and participants with high BMI (>30 kg/m²; n = 7) were obtained before and after treadmill walking. The outer margins of the tibia, the medial and lateral cartilage surfaces, and the meniscal footprints were segmented on each MR image to create 3-dimensional models of the joint. Cartilage thickness was measured before and after walking in areas covered and uncovered by the menisci. Cartilage compressive strain was then determined from changes in thickness resulting from the walking task.

Results

Before exercise, medial and lateral uncovered cartilage of the tibial plateau was significantly thicker than covered cartilage in both BMI groups. In the uncovered region of the lateral tibial plateau, participants with high BMI had thinner preexercise cartilage than those with a normal BMI. Cartilage compressive strain was significantly greater in medial and lateral cartilage in participants with high BMI compared with those with normal BMI in both the regions covered and those uncovered by the menisci.

Conclusion

Participants with high BMI experienced greater cartilage strain in response to walking than participants with normal BMI in both covered and uncovered regions of cartilage, which may indicate that the load-distributing function of the meniscus is not sufficient to moderate the effects of obesity.

Clinical Relevance

These findings demonstrate the critical effect of obesity on cartilage function and thickness in regions covered and uncovered by the menisci.

Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models

As the most common chronic degenerative joint disease, osteoarthritis (OA) is the leading cause of pain and physical disability, affecting millions of people worldwide. Mainly characterized by articular cartilage degradation, osteophyte formation, subchondral bone remodeling, and synovial inflammation, OA is a heterogeneous disease that impacts all component tissues of the articular joint organ. Pathological changes, and thus symptoms, vary from person to person, underscoring the critical need of personalized therapies. However, there has only been limited progress towards the prevention and treatment of OA, and there are no approved effective disease-modifying osteoarthritis drugs (DMOADs). Conventional treatments, including non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy, are still the major remedies to manage the symptoms until the need for total joint replacement. In this review, we provide an update of the known OA risk factors and relevant mechanisms of action. In addition, given that the lack of biologically relevant models to recapitulate human OA pathogenesis represents one of the major roadblocks in developing DMOADs, we discuss current in vivo and in vitro experimental OA models, with special emphasis on recent development and application potential of human cell-derived microphysiological tissue chip platforms.

Resveratrol inhibits the development of obesity-related osteoarthritis via the TLR4 and PI3K/Akt signaling pathways

Aim of the study: Obesity leads to mild, chronic inflammation which is a primary risk factor for osteoarthritis (OA). Resveratrol exerts a protective effect on OA through its anti-inflammatory properties, but the precise mechanism remains unknown. The present study aimed to investigate the mechanism by which resveratrol alleviates obesity-related OA, and whether it is linked to the TLR4 and PI3K/Akt signaling pathways. Materials and methods: C57BL/6J male mice were fed a high-fat diet (HFD) with or without resveratrol treatment and knee joints were collected for analysis. In addition, IL-1β-induced SW1353 cells were used to study in vitro the reciprocal effects of TLR4 and PI3K/Akt pathways. Results: Resveratrol inhibited the development of OA in mice fed a HFD. TLR4 and PI3K/Akt signaling pathways were both activated in the articular cartilage; resveratrol treatment down-regulated TLR4 but up-regulated PI3K/Akt signaling. Further in vitro results showed that the effect of resveratrol alone on activation of PI3K/Akt was attenuated but not abolished by the TLR4 inhibitor CLI-095, and resveratrol failed to reduce TLR4 protein expression in IL-1β stimulated cells pretreated with the PI3K inhibitor LY294002. Conclusions: Resveratrol may exert an anti-osteoarthritic effect by inhibiting TLR4 via the activation of PI3K/Akt signaling pathways. Resveratrol has potential as a drug for OA prevention.