How Physical Activity Affects Knee Cartilage and a Standard Intervention Procedure for an Exercise Program: A Systematic Review

Plyometric training increases thickness and volume of knee articular cartilage in mice

Degeneration and thinning of articular cartilage lead to osteoarthritis and may result from reduced joint loading during e.g. bed rest or as a result of microgravity during space flight. Anabolic physical exercises for cartilage are not well studied to date. We built an experimental apparatus for plyometric training with mice to test potential benefits of jumping for articular cartilage. The exercise group (JUMP) performed jump training for 9 weeks and was compared with sedentary mice (control, CON) and hindlimb-suspended (HLS) mice (to simulate reduced loading) for the same duration. Knee cartilage was assessed via 3-dimensional reconstruction of micro-CT scans and histology. We observed significant thinning and volume reduction of articular cartilage at the medial tibial-femoral point of contact in the HLS group. Clustering of chondrocytes was present in HLS. By contrast, the JUMP group showed both cartilage thickening and volume increase. We observed a similar trend on trabecular bone thickness and volume. Our results show that plyometric training can stimulate cartilage thickness and volume in mice. This suggests further investigation of this mode of exercise as a countermeasure to prevent cartilage atrophy in disuse scenarios such as long duration spaceflight, and for patients at risk of developing osteoarthritis.

Classification of Physical Activity Programs Based on the Kellgren & Lawrence Scale for Knee Osteoarthritis: A Systematic Review

INTRODUCTION

Knee osteoarthritis is a common orthopaedic disease, is the leading cause of disability in the elderly, and can lead to pain, loss of function, and reduced quality of life. This research aims to determine how PA programs can be effectively classified and customised to align with the stages of knee OA according to the KL classification.

OBJECTIVE

The research aims to fill the gap in understanding the relationship between the type and intensity of PA and the stages of OA as defined by the KL classification.

MATERIALS AND METHODS

A systematic search was performed using PubMed, Web of Science, and Scopus databases. This review included different types of studies published after January 1, 2013.

RESULTS

Two thousand one hundred and thirty-six were picked up and only nine articles met the inclusion criteria. The beneficial effects of exercise were found in the function of the joints, pain, and quality of life. Aerobic, isometric, and resistance training showed positive effects and presented improvements in physical function, quality of life, and pain.

CONCLUSION

The exercise programs appear to be both safe and effective in subjects with knee osteoarthritis with regard to quality of life, pain, and knee function.

TRIAL REGISTRATION

PROSPERO registration number: CRD42024550463.

Effects of long-term running on the structure and biochemical composition of knee cartilage in males: a cross-sectional study

Background

Running has been widely recognized as a beneficial activity for improving physical fitness, but it can also increase the risk of running-related injuries (RRIs). This study aims to assess the impact of long-term running on the structural and biochemical composition of the knee.

Methods

This study recruited a total of 32 participants, including 16 male recreational runners, aged 28-49 years, with a running experience of 2-7 years, and 16 matched sedentary controls. Magnetic resonance (MR) scans of T2* mapping and three-dimensional double-echo steady-state (3D-DESS) were performed on all participants. The volumes, thickness, and T2* values of joint articular cartilage were obtained via automatic segmentation software.

Results

Compared with the sedentary controls, runners exhibited significant increases in the volumes of both the femoral medial articular cartilage and the tibial medial articular cartilage. Additionally, there were significant increases in the thickness of several cartilage regions, including femoral medial cartilage, femoral medial articular cartilage, femoral medial thickness, femoral lateral cartilage, and tibial medial articular cartilage. Notably, the T2* values in the femoral lateral and tibial lateral cartilage of runners decreased significantly, while those in the patellar cartilage and medial tibial cartilage increased significantly. Runner pace was negatively correlated with the overall knee cartilage thickness (r=-0.556; P=0.02), femoral cartilage thickness (r=-0.533; P=0.03), and volume (r=-0.532; P=0.03) but positively correlated with the T2* value of the patellar cartilage (r=0.577; P=0.01).

Conclusions

Our study suggests that long-term mechanical stress from running may lead to increased thickness and volume in certain knee joint cartilage regions, possibly enhancing the functional adaptability of knee cartilage. The varying changes in T2* value in the tibial and fibular cartilage areas may indicate differing adaptability to pressure.

Efficacy of virtual reality exercise in knee osteoarthritis rehabilitation: a systematic review and meta-analysis

Background

This systematic review and meta-analysis aims to investigate the effects of virtual reality (VR) exercise compared to traditional rehabilitation on pain, function, and muscle strength in patients with knee osteoarthritis (KOA). Additionally, the study explores the mechanisms by which VR exercise contributes to the rehabilitation of KOA patients.

Methods

We systematically searched PubMed, the Cochrane Library, Embase, Web of Science, Scopus, and PEDro according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our search spanned from the library construction to 24 May 2024, focusing on randomized controlled trials Primary outcomes included pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and muscle strength. Meta-analysis was conducted using RevMan (version 5.4) and Stata (version 14.0). The bias risk of included studies was assessed using the Cochrane RoB 2.0 tool, while the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

Results

This meta-analysis and systematic review included nine studies involving 456 KOA patients. The results indicated that VR exercise significantly improved pain scores (SMD, -1.53; 95% CI: -2.50 to -0.55; p = 0.002), WOMAC total score (MD, -14.79; 95% CI: -28.26 to -1.33; p = 0.03), WOMAC pain score (MD, -0.93; 95% CI: -1.52 to -0.34; p = 0.002), knee extensor strength (SMD, 0.51; 95% CI: 0.14 to 0.87; p = 0.006), and knee flexor strength (SMD, 0.65; 95% CI: 0.28 to 1.01; p = 0.0005), but not significantly for WOMAC stiffness (MD, -0.01; 95% CI: -1.21 to 1.19; p = 0.99) and physical function (MD, -0.35; 95% CI: -0.79 to -0.09; p = 0.12).

Conclusion

VR exercise significantly alleviates pain, enhances muscle strength and WOMAC total score in KOA patients, but improvements in joint stiffness and physical function are not significant. However, the current number of studies is limited, necessitating further research to expand on the present findings.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024540061, identifier CRD42024540061.

Adherence to Exercise Training and Physical Function in Older Adults Diagnosed with Knee Osteoarthritis

Background

Knee osteoarthritis (KOA) provokes pain, muscle weakness, and consequent impairment in activities of daily living. On the other hand, adherence to exercise training (ET) is associated with the attenuation of the impairments. The aims of the present study were to a) investigate adherence to ET in older adults with KOA diagnosed attending public service; and b) to analyze the physical function of the older adults with KOA who did not adhere to the ET in public service.

Methods

The adherence to ET programs was analyzed retrospectively from each patient's date of KOA diagnosis. After assessing the adherence to ET, the physical function of these older adults diagnosed with KOA (n=19) was analyzed and compared with another group composed of asymptomatic sedentary older adults without evidence of KOA (ASKOA) (n=17).

Results

Although all older adults with KOA received guidelines to practice ET, only 58% were able to start a program. Additionally, 100% of the sample could not perform ET uninterruptedly. According to the findings, close to 80% of older adults had difficulties scheduling ET sessions in public places. Subjects with KOA (12.1±3.1; IC95%:10.6-13.6) had worse lower limb functional capacity than ASKOA (8.1±1.0; IC95%:7.6-8.6; p<.001; δ=4.0 sec; d=1.7). Likewise, they had a lower dynamic balance than KOA (12.4±2.7; IC95%:11.1-13.7 vs. 8.0±1.1; IC95%:7.4-8.6; p<.001; δ=4.4 sec; d=2.1).

Conclusions

The investigated sample has a lack of ET adherence by difficulties in scheduling ET sessions in public places. In addition, it demonstrated impairment in physical function in older adults with KOA.

Molecular Assessment of Healthy Pathological Articular Cartilages in Physically Active People: A Scoping Review

Physiological aging triggers a cascade of negative effects on the human body and the human joint is only one of the several compartments affected by this irreversible and natural process. Osteoarthritis and cartilage degeneration can cause pain and disability; therefore, identifying the molecular processes underlying these phenomena and the biomarkers produced during physical activity is of critical importance. In the present review, the main goal was to identify and discuss the articular cartilage biomarkers analyzed in studies in which physical or sports activities were adopted and eventually to propose a standard operating procedure for the assessment. Articles collected from Pubmed, Web of Science, and Scopus were scrutinized to detect reliable cartilage biomarkers. The principal articular cartilage biomarkers detected in these studies were cartilage oligomeric matrix protein, matrix metalloproteinases, interleukins, and carboxy-terminal telopeptide. The articular cartilage biomarkers identified in this scoping review may aid in a better comprehension of where research on the topic is heading and offer a viable instrument for streamlining investigations on cartilage biomarker discovery.

Simulating Knee-Stress Distribution Using a Computed Tomography-Based Finite Element Model: A Case Study

This study aimed to evaluate the mechanism of progression involved in knee osteoarthritis (OA). We used the computed tomography-based finite element method (CT-FEM) of quantitative X-ray CT imaging to calculate and create a model of the load response phase, wherein the greatest burden is placed on the knee joint while walking. Weight gain was simulated by asking a male individual with a normal gait to carry sandbags on both shoulders. We developed a CT-FEM model that incorporated walking characteristics of individuals. Upon simulating changes owing to a weight gain of approximately 20%, the equivalent stress increased extensively in both medial and lower leg aspects of the femur and increased medio-posteriorly by approximately 230%. As the varus angle increased, stress on the surface of the femoral cartilage did not change significantly. However, the equivalent stress on the surface of the subchondral femur was distributed over a wider area, increasing by approximately 170% in the medio-posterior direction. The range of equivalent stress affecting the lower-leg end of the knee joint widened, and stress on the posterior medial side also increased significantly. It was reconfirmed that weight gain and varus enhancement increase knee-joint stress and cause the progression of OA.

Outcome Expectations and Older Adults with Knee Osteoarthritis: Their Exercise Outcome Expectations in Relation to Perceived Health, Self-Efficacy, and Fear of Falling

Outcome expectations are a determinant of exercise engagement and adherence. However, the factors that influence outcome expectations for exercise remain poorly understood for people with knee osteoarthritis. In this paper, a cross-sectional study was conducted by recruiting 211 older adults from three clinics in Southern Taiwan. This study explored older adults with knee osteoarthritis exercise outcome expectations and perceived health, self- efficacy, and fear of falling. The older adults completed the Outcome Expectations for Exercise Scale (OEES), the pain and physical function subscales of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Perceived Health Status Scale, the Self-Efficacy for Exercise scale (SEE- C), the Activities-Specific Balance Confidence Scale (ABC), the Geriatric Depression Scale (GDS). Multiple logistic regression models were used to determine associations between outcome expectations for exercise and physical and psychosocial outcomes in the knee OA population. Among the participants of the cross-sectional study, the mean age was 72.04 (SD = 5.53) years, and 71.6% were female. Higher outcome expectations for exercise were associated with higher physical function (OR = 0.98; 95% CI [0.96−1.99]; p = 0.007), better perceived health (OR = 1.30; 95% CI [1.12−1.51]; p < 0.001), greater self-efficacy (OR =1.03; 95% CI [1.01−1.04]; p = 0.006), and less fear of falling (OR = 3.33; 95% CI [1.21−9.19]; p = 0.020). Thus, the results indicated that outcome expectations for exercise among the participants were significantly associated with physical function, perceived health, self-efficacy, and fear of falling. These findings suggest the importance of personal factors in the design of interventions to promote exercise behavior changes among elderly patients with Knee Osteoarthritis.