What is the effect of physical activity on the knee joint? A systematic review

Factors associated with meniscus volume in knees free of degenerative features

OBJECTIVES

To explore factors that were associated with meniscus volume in knees free of radiographic osteoarthritis (OA) features and symptoms of OA.

METHODS

In the third Rotterdam Study cohort, clinical, radiographic, and magnetic resonance data were obtained at baseline (BL) and after 5 years of follow-up. Meniscus volumes and their change over time were calculated after semi-automatic segmentation on Magnetic Resonance Imaging. Knees with radiographic OA features (Kellgren and Lawrence>0) or clinical diagnosis of OA (American College of Rheumatology) at BL were excluded. Ten OA risk factors were adjusted in the multivariable analysis (generalized estimating equations), treating two knees within subjects as repeated measurements.

RESULTS

From 1065 knees (570 subjects), the average (standard deviation) age and Body mass index (BMI) of included subjects were 54.3 (3.7) years and 26.5 (4.4) kg/m2. At BL, nine factors (varus alignment, higher BMI, meniscus pathologies, meniscus extrusion, cartilage lesions, injury, greater physical activity level, quadriceps muscle strength, and higher age) were significantly associated with greater meniscus volume. Five factors (injury, meniscus pathologies, meniscus extrusion, higher age, and change of BMI) were significantly associated with meniscus volume loss.

CONCLUSIONS

Modifiable factors (varus alignment, BMI, physical activity level, and quadriceps muscle strength) and non-modifiable factors (higher age, injury, meniscus pathologies, meniscus extrusion, and cartilage lesions) were all associated with meniscus volume or meniscus volume loss over time.

Fundamentals of osteoarthritis. Rehabilitation: Exercise, diet, biomechanics, and physical therapist-delivered interventions

Insights related to the pathogenesis of osteoarthritis (OA) have informed rehabilitative treatments that aim to mitigate the influence of several known impairments and risk factors for OA, with the goal to improve pain, function, and quality of life. The purpose of this invited narrative review is to provide fundamental knowledge to non-specialists about exercise and education, diet, biomechanical interventions, and other physical therapist-delivered treatments. In addition to summarizing the rationale for common rehabilitative therapies, we provide a synthesis of current core recommendations. Robust evidence based on randomized clinical trials supports exercise with education and diet as core treatments for OA. Structured, supervised exercise therapy is advised. The mode of exercise may vary but should be individualized. The dose should be based on an initial assessment, the desired physiological changes, and progressed when appropriate. Diet combined with exercise is strongly recommended and studies demonstrate a dose-response relationship between the magnitude of weight loss and symptom improvement. Recent evidence suggests the use of technology to remotely deliver exercise, diet and education interventions is cost-effective. Although several studies support the mechanisms for biomechanical interventions (e.g., bracing, shoe inserts) and physical therapist-delivered (passive) treatments (e.g., manual therapy, electrotherapeutic modalities) fewer rigorous randomized trials support their clinical use; these therapies are sometimes recommended as adjuncts to core treatments. The mechanisms of action for all rehabilitative interventions include contextual factors such as attention and placebo effects. These effects can challenge our interpretation of treatment efficacy from clinical trials, yet also provide opportunities to maximize patient outcomes in clinical practice. When evaluating rehabilitative interventions, the field may benefit from increased emphasis on research that considers contextual factors while evaluating mechanistic, longer-term, clinically-important and policy-relevant outcome measures.

Physical Activity and Features of Knee Osteoarthritis on Magnetic Resonance Imaging in Individuals Without Osteoarthritis: A Systematic Review

OBJECTIVE

To systematically review all studies that have evaluated the association between physical activity (PA) levels and features of knee osteoarthritis (OA) on magnetic resonance imaging (MRI) for subjects without OA.

METHODS

The inclusion criteria for prospective studies were as follows: 1) subjects without OA; 2) average age 35-80 years; and 3) any self-reported PA or objective measurement of PA. The eligible MRI outcomes were OA-related measures of intraarticular knee joint structures. Exclusion criteria were evaluations of instant associations with transient structural changes after PA.

RESULTS

Two randomized controlled trials and 16 observational studies were included. One of 11 studies found that PA was harmfully related to cartilage volume or thickness, but 4 studies found a significant protective association. Four of 10 studies found that PA was harmfully related to cartilage defects, while others showed no significant associations. Two of 3 studies reported a significantly increased cartilage T2 value in individuals with more PA. All 3 studies reported no significant association between PA and bone marrow lesions. Two studies assessed the association between PA and meniscus pathology, in which only occupational PA involving knee bending was associated with a greater risk of progression.

CONCLUSION

Within the sparse and diverse evidence available, no strong evidence was found for the presence or absence of an association between PA and the presence or progression of features of OA on MRI among subjects without OA. Therefore, more research is required before PA in general and also specific forms of PA can be deemed safe for knee joint structures.

Effect of different Intensity Electrotherapy on Functional Recovery in Patients with Knee Osteoarthritis

Objective To explore the effects of different-intensity intermediate frequency therapy on functional recovery of patients with knee osteoarthritis.

Methods Three-band electromagnetic waves of constant amplitude intermediate frequency electrotherapy group (Group A), interference electrotherapy group (Group B) and modulated intermediate frequency electrotherapy group (Group C) were used to treat knee osteoarthritis (KOA) patients, 20 min/time, 1 time/day and 5 days/week for four weeks. Other rehabilitation items were performed the same way. The rehabilitation therapy were evaluated by VAS score, Timed Up and Go test and balance ability.

Results After 4 weeks of treatment, the treatment effects of the three groups were all significant compared with the pre-treatment. Among the three groups, the treatment effect of Group B was better than that of the other two groups, and there was no significant difference in the treatment effect between Group A and Group C.

Conclusion According to thee. g.results, it is possible that the interference current is of a great action depth, and the "endogenous" low-frequency modulated intermediate frequency current possesses the advantages of both low and intermediate frequency, so with the intermediate frequency current getting through the high resistance of skin, the current effect of the low and intermediate frequency in the deep part of the human body can be achieved.

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

(1) Background: Cartilage degeneration with the natural aging process and the role of physical activity on cartilage wellness is still not clear. The objective of the present review was to understand how different physical activity interventions affect the cartilage and to propose a Standard Operating Procedure for an exercise program to maintain knee joint health; (2) Methods: Articles were collected on three different electronic databases and screened against the eligibility criteria. Results were collected in tables and the main outcomes were discussed narratively; (3) Results: A total of 24 studies have been included after the screening process and aerobic, strength, flexibility, postural balance, and mobility interventions were detected. Different protocols and types of interventions were adopted by the authors; (4) Conclusions: Physical activity interventions have mainly positive outcomes on cartilage structure, but the protocols adopted are different and various. A Standard Operating Procedure has been proposed for a physical intervention focalized on cartilage wellness that could be adopted as an intervention in the clinical setting. Furthermore, the creation of a standardized protocol wants to help scientific research to move in the same direction.

How Do People With Knee Osteoarthritis Conceptualize Knee Confidence? A Qualitative Study

OBJECTIVE

Reduced knee confidence is common in people with knee osteoarthritis (OA) and is likely to influence how people with knee OA engage with movement and activities. However, there is conflicting evidence surrounding the association between confidence and function. This may be because knee confidence has been assessed via a single questionnaire item that was not developed for people with knee OA and thus may not provide an accurate or comprehensive assessment of confidence in this population. A better understanding of knee confidence could inform a more thorough assessment of the construct both in clinical and research contexts. Therefore, the aim of this study was to explore the meaning of knee confidence from the perspective of people with knee OA.

METHODS

Fifty-one people with a clinical diagnosis of knee OA took part in a one-to-one semistructured interview. Interviews explored how each participant conceptualized knee confidence. Reflexive thematic analysis was selected as a flexible approach for identifying patterns of meaning across cases through a combination of data-driven and theory-informed coding of the transcribed data.

RESULTS

People with knee OA conceptualized confidence with reference to 1 or more of 4 themes: (1) symptoms, (2) functional ability, (3) the internal structure of the knee, and (4) knowledge about knee OA and its management. Each conceptualization of confidence was associated with present and future concerns.

CONCLUSION

Because people with knee OA conceptualize knee confidence in different ways, a single-item measure is unlikely to capture all of the aspects of this construct in this population. This may explain the conflicting evidence around the association between reduced knee confidence and function in people with knee OA.

IMPACT

This study showed that a multi-item measure is needed to measure knee confidence in people with knee OA. Clinicians and researchers need to understand what knee confidence means to people with knee OA, because it is likely to influence how these individuals engage with movement and activities. Understanding this relationship can enable more targeted education and functional rehabilitation for people with knee OA.

Elderly Runners and Osteoarthritis: A Systematic Review

PURPOSE

The impact of running on the onset of osteoarthritis (OA) is controversial. This study compared the incidence of OA in elderly runners versus nonrunners.

MATERIAL AND METHODS

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google scholar, Embase, and Web of Science databases were accessed in January 2022. All the published clinical studies investigating OA onset in runners versus non-runners were considered. Studies reporting data on OA and participants in other sports were excluded. Only studies investigating patients with a mean age older than 55 years were considered. The methodological quality of the articles was evaluated using the Newcastle-Ottawa Scale (NOS).

RESULTS

Data from 3001 participants and 6674 joints were retrieved. The mean age was 59.4±2.7 years. The mean body mass index was 24.6±2.5 kg/m2. The 5 included articles (963 runners, 2038 nonrunners) did not report significant differences in runners compared with controls.

CONCLUSION

Middle aged runners did not present greater imaging or clinical signs of OA compared with nonrunner controls. Running at elite or recreational level did not increase the rate of OA progression in individuals older than 50 years.

Osteoarthritis in Athletes Versus Nonathletes: A Systematic Review

INTRODUCTION

Joint overload and sport-related injuries may accelerate the development of osteoarthritis (OA). A systematic review of the literature was performed to establish the risk of athletes to develop premature OA compared with nonathletes.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. PubMed, Google scholar, Embase, and Web of Science databases were accessed in June 2021. All the published clinical studies investigating OA onset in athletes versus nonathletes were considered. Studies reporting data on secondary and/or post-traumatic OA were excluded.

RESULTS

Data from 32 articles (20,288 patients) were retrieved. The mean age was 67.8±10.0 years and the mean body mass index was 25.0±2.5 kg/m2. 74% (6859 patients) of the athletes suffered from premature OA. Of them, 21% were active in soccer, 11% in handball, 11% in ice-hockey, 3% in football, and 0.3% in rugby. 26% of the athletes reported no significant differences in OA progression compared with healthy controls. Of these athletes, 47% were runners, 5% dancers, and 1% triathletes.

CONCLUSION

Certain sports, such as soccer, handball, ice-hockey, and rugby are more likely to be associated with premature knee and hip OA. Conversely, runners and ballet dancers do not evidence significant increase in OA. Moderate and recreational exposure to aerobic sports does not accelerate the development of OA.

T2 Mapping Values in Postmeniscectomy Knee Articular Cartilage after Running: Early Signs of Osteoarthritis?

Loading on the joints during running may have a deleterious effect on post-partial meniscectomy knee cartilage, leading to osteoarthritis. Utilizing T2-mapping measurements before and after running may enable the observation of changes in the articular cartilage of the postmeniscectomy knees compared with healthy knees. After medial partial meniscectomy, 12 volunteers underwent magnetic resonance imaging (MRI) of the both knees, before and immediately after 30 minutes of running. Quantitative assessment of articular cartilage was performed using a T2-mapping technique. In the medial compartment of the operated knees, significantly lower T2 values were found in anterior tibial plateau (pre- vs. postrun: 33.85 vs. 30.45 ms; p = 0.003) and central tibial plateau (33.33 vs. 30.63 ms; p = 0.007). Similar differences were found in lateral regions of central femur (post- vs. prerun: 35.86 vs. 40.35 ms; p = 0.015), posterior femur (34.89 vs. 37.73 ms; p = 0.001), and anterior tibia (24.66 vs. 28.70 ms, p = 0.0004). In lateral compartment, postrun values were significantly lower in operated compared with healthy knees, in central femur (34.89 vs. 37.59 ms; p = 0.043), posterior femoral (36.88 vs. 39.36 ms; p = 0.017), anterior tibia (24.66 vs. 30.20 ms; p = 0.009), and posterior tibia (28.84 vs. 33.17 ms; p = 0.006). No statistical difference was found while comparing postrun to prerun healthy knees. Lower T2 values were found in operated knees after 30 minutes of running. These changes were seen in medial and lateral compartments. We suspect that running may subject the articular cartilage to excessive loads in the post-partial meniscectomy knee, loads that in healthy knee do not cause any changes.

The Association Between Physical Activity Level and Severity of Knee Osteoarthritis: A Single Centre Study in Saudi Arabia

Background and aim Knee osteoarthritis (OA) is a disabling joint disease that results in degeneration of the joint cartilage. Many studies demonstrate the risk factors and complications of knee osteoarthritis, but how physical activity impacts the osteoarthritis severity needs to be studied. The study aimed to assess the impact and association of physical activity level with the severity of knee osteoarthritis among patients attending a single center in the Aseer region, southwest Saudi Arabia. Methods An analytical cross-sectional study was conducted targeting all patients clinically diagnosed with knee osteoarthritis in the Aseer region from June 2021 to September 2021. Data was collected using a pre-structured online questionnaire. The questionnaire included patients' socio-demographic data and clinical data on knee osteoarthritis. The level of physical activity was assessed using the International Physical Activity Questionnaire (IPAQ). The severity of knee osteoarthritis was assessed using the index of severity for osteoarthritis of the knee. Results Out of 473 patients clinically diagnosed with knee OA, only 145 patients met our inclusion criteria. Patients' ages ranged from 35 years to 71 years, with a mean age of 44.3 (±12.9) years. A total of 122 (84.1%) patients were females. Sixty-five (44.8%) patients complained of knee OA for less than two years, 46 (31.7%) for two to five years, and 34 (23.4%) were diagnosed for more than five years. A total of 96 (66.2%) had a low level of physical activity, 32 (22.1%) had a moderate level of physical activity, while 17 (11.7%) had a high level of physical activity. Thirty-eight (26.2%) cases complained of extremely severe knee OA, 37 (25.5%) had very severe knee OA, 28 (19.3%) complained of severe knee OA, 36 (24.9%) had mild to moderate knee OA, while six (4.1%) had minimal knee OA. There was a significant beneficial effect of physical activity on the severity of knee OA. Conclusion The study revealed that physical activity, especially at high levels, was associated with lower knee OA severity which means a beneficial effect. Most of the patients included in the study had severe to extremely severe knee OA with low physical activity levels.

The prevalence of patellofemoral pain in the Rugby League World Cup (RLWC) 2021 spectators: A protocol of a cross-sectional study

Patellofemoral pain (PFP) can cause significant pain leading to limitations in societal participation and physical activity. PFP is usually associated with athletes undergoing intensive physical training, or military recruits; but recent evidence shows that PFP is common in the general population. The relationship of PFP with physical activity is not entirely clear. Our aim is to provide a better estimate of the general population prevalence of PFP and to relate this to the level of physical activity, and demographic characteristics. The Survey instrument for Natural history, Aetiology and Prevalence of Patellofemoral pain Studies (SNAPPS) was developed as a PFP screening tool to be used in the community. The electronic version of the SNAPPS (eSNAPPS) has recently been validated and was used to survey attendees at mass-participation running events. We will use an electronic survey to collect data from a sample of 1100 Rugby League World Cup spectators. The survey will have four sections: i) general and demographic; ii) knee pain (eSNAPPS); iii) level of physical activity; and iv) quality of life in relation to knee pain. The primary analytic approach will be descriptive of PFP prevalence. Secondary analyses will explore the relationships of the presence of PFP and the other variables. We will disseminate this work by publication of peer-reviewed papers in scientific journals, presentations at scientific conferences, and on the dedicated SNAPPS website https://www.snappspfp.com/.

Anti-inflammatory effects of tibial axial loading on knee articular cartilage post traumatic injury

Early therapeutic intervention to mitigate inflammatory responses following joint injury may offer a potential strategy to prevent post-traumatic osteoarthritis (PTOA). In-vitro studies have demonstrated uniaxial dynamic compression mitigates the catabolic and apoptotic responses of articular cartilage (AC) in response to mechanical injury. The objectives of this study were (1) to develop a custom device that can apply dynamic tibial axial loading (TAL) to knee AC by mimicking therapeutic, in-vitro loading conditions and (2) to investigate the potential of TAL to reduce the inflammatory response of AC post traumatic acute joint injury using an ex-vivo porcine model. A TAL device was fabricated to apply dynamic compressive loading to knee AC by combining tibial axial compressive loading with continuous passive motion. Computational analyses demonstrated that the loading condition applied to the knee by the TAL device closely simulate uniaxial dynamic compression reported in previous in-vitro studies. Following single impact injury, injured porcine knees were subjected to TAL with a magnitude of 1/4 body weight at a frequency of 1 Hz for 30 min. AC samples were harvested 8 h post injury for analysis of pro-inflammatory cytokine expression (IL-1β and TNF-α). Expression of both cytokines was upregulated following injury; however, the change was notably mitigated in the specimens subjected to TAL. Thus, TAL may be an effective and potentially, practical-to-administer early intervention strategy to mitigate rapidly occurring detrimental events following acute AC injury, potentially slowing down progression to PTOA.

Is the association between physical activity and fatigue mediated by physical function or depressive symptoms in symptomatic knee osteoarthritis? The Multicenter Osteoarthritis Study

Objectives: To examine whether physical activity (PA) was associated with fatigue, and quantify the extent of potential mediation through depressive symptoms or physical function (PF) on the relationship between PA and fatigue in symptomatic knee osteoarthritis (KOA).Method: This longitudinal study used data from the Multicenter Osteoarthritis Study (n = 484), comprising subjects aged ≥ 50 years. Baseline PA was quantified via an ankle-worn accelerometer. The outcome was fatigue, measured using a 0-10 rating scale at 2 year follow-up. Mediators included gait speed as a measure of PF and depressive symptoms at 2 year follow-up. Mediation analysis was carried out after adjustment for baseline confounders. Stratified analysis by baseline fatigue status [no/low (< 4) and high (≥ 4) fatigue] was performed.Results: A significant direct association was found between PA and fatigue at 2 years [unstandardized coefficient (B) = -0.054; 95% confidence interval (CI) -0.107, -0.002, p = 0.041]. The PA-fatigue relationship was not mediated by gait speed (B = -0.006; 95% CI -0.018, 0.001) or depressive symptoms (B = 0.009; 95% CI 0.009, 0.028). In the subgroup with high baseline fatigue, direct associations were found between PA and fatigue (gait speed model:, B = -0.107; 95% CI -0.212, -0.002, p = 0.046; depressive symptoms model: B = -0.110; 95% CI -0.120, -0.020, p = 0.017); but in the no/low baseline fatigue group, no significant association was found between PA and fatigue.Conclusion: In the symptomatic KOA population, higher baseline PA was directly associated with reduced fatigue 2 years later, especially in those with high baseline fatigue. However, this relationship was not mediated by depressive symptoms or PF.

A biomarker perspective on the acute effect of exercise with and without impact on joint tissue turnover: an exploratory randomized cross-over study

PURPOSE

To investigate acute changes in biochemical markers of bone and cartilage turnover in response to moderate intensity exercise with and without joint impact in healthy human subjects.

METHODS

A randomized, cross-over, exploratory, clinical study was conducted. Twenty healthy subjects with no history of joint trauma completed 30 min interventions of standardized moderate intensity cycling and running as well as a resting intervention 1 week apart. Blood samples were taken immediately before, four times after exercise and again the next day. Urine was sampled, before, after and the next day. On the day of rest, samples were taken at timepoints similar to the days of exercise. Markers of type I (CTX-I), II (C2M, CTX-II) and VI (C6M) collagen degradation, cartilage oligomeric matrix protein (COMP) and procollagen C-2 (PRO-C2) was measured.

TRIAL REGISTRATION NUMBER

NCT04542655, 02 September 2020, retrospectively registered.

RESULTS

CTX-I was different from cycling (4.2%, 95%CI: 0.4-8.0%, p = 0.03) and resting (6.8%, 95%CI: 2.9-10.7%, p = 0.001) after running and the mean change in COMP was different from cycling (10.3%, 95%CI: 1.1-19.5%, p = 0.03), but not from resting (8.6%, 95%CI: - 0.7-17.8%, p = 0.07) after running. Overall, changes in other biomarkers were not different between interventions.

CONCLUSION

In this exploratory study, running, but not cycling, at a moderate intensity and duration induced acute changes in biomarkers of bone and cartilage extra-cellular matrix turnover.

Association of body composition, physical activity and physical performance with knee cartilage thickness and bone area in young adults

OBJECTIVE

To describe associations of body composition, physical activity and physical performance with knee cartilage thickness and subchondral bone area in young adults.

METHODS

Body composition, physical activity and physical performance were measured 4-5 years prior to knee MRI. Cartilage thickness and bone area were measured quantitatively from MRI. Associations were assessed using linear regression analysis, with mediators being identified using mediation analysis.

RESULTS

Participants (n = 186) were 31-41 years of age when the MRI was acquired and 48% were female. Greater lean mass was positively associated with cartilage thickness [β = 6.52 μm/kg (95% CI 0.86, 12.18)] and bone area [β = 13.37 mm2/kg (95% CI 5.43, 21.31)]. Physical performance measures were positively associated with cartilage thickness [long jump: β = 2.44 μm/cm (95% CI 0.70, 4.18); hand grip strength: 7.74 μm/kg (95% CI 1.50, 13.98); physical work capacity: 1.07 μm/W (95% CI 0.29, 1.85)] and bone area [long jump: β = 3.99 mm2/cm (95% CI 0.64, 7.34); hand grip strength: 19.06 mm2/kg (95% CI 7.21, 30.92); leg strength: 3.18 mm2/kg (95% CI 1.09, 5.28); physical work capacity: 3.15 mm2/W (95% CI 1.70, 4.60)]. Mediation analysis suggested these associations were mediated by lean mass (effect mediated: 27-95%).

CONCLUSION

Greater lean mass and better physical performance measured 4-5 years prior were associated with greater knee cartilage thickness and subchondral bone area in young adults, and the associations of physical performance were largely mediated by lean mass. These findings suggest lean mass may play an important role in maintaining knee joint health in young adults.

A mobile MRI field study of the biochemical cartilage reaction of the knee joint during a 4,486 km transcontinental multistage ultra-marathon using T2* mapping

Nearly nothing is known about the consequences of ultra-long-distance running on knee cartilage. In this mobile MRI field study, we analysed the biochemical effects of a 4,486 km transcontinental multistage ultra-marathon on femorotibial joint (FTJ) cartilage. Serial MRI data were acquired from 22 subjects (20 male, 18 finisher) using a 1.5 T MR scanner mounted on a 38-ton trailer, travelling with the participants of the TransEurope FootRace (TEFR) day by day over 64 stages. The statistical analyses focused on intrachondral T2* behaviour during the course of the TEFR as the main outcome variable of interest. T2* mapping (sagittal FLASH T2* weighted gradient echo) is a validated and highly accurate method for quantitative compositional cartilage analysis of specific weightbearing areas of the FTJ. T2* mapping is sensitive to changes in the equilibrium of free intrachondral water, which depends on the content and orientation of collagen and the proteoglycan content in the extracellular cartilage matrix. Within the first 1,100 km, a significant running load-induced T2* increase occurred in all joint regions: 44.0% femoral-lateral, 42.9% tibial-lateral, 34.9% femoral-medial, and 25.1% tibial-medial. Osteochondral lesions showed no relevant changes or new occurrence during the TEFR. The reasons for stopping the race were not associated with knee problems. As no further T2* elevation was found in the second half of the TEFR but a decreasing T2* trend (recovery) was observed after the 3,500 km run, we assume that no further softening of the cartilage occurs with ongoing running burden over ultra-long distances extending 4,500 km. Instead, we assume the ability of the FTJ cartilage matrix to reorganize and adapt to the load.

Cruciate ligament healing and injury prevention in the age of regenerative medicine and technostress: homeostasis revisited

PURPOSE

This clinical concepts paper discusses the essential elements of cruciate ligament recuperation, micro-trauma repair, and remodeling.

METHODS

Cruciate ligament mechanobiology and tissue heterogeneity, anatomy and vascularity, and synovial membrane and fluid functions are discussed in relationship to deficiency-induced inflammatory responses, nervous and immune system function, recuperation, repair and remodeling, and modern threats to homeostasis.

RESULTS

Cruciate ligament surgical procedures do not appreciate the vital linked functions of the central, peripheral, and autonomic nervous systems and immune system function on knee ligament injury recuperation, micro-trauma repair, and remodeling. Enhanced knowledge of these systems could provide innovative ways to decrease primary non-contact knee injury rates and improve outcomes following reconstruction or primary repair.

CONCLUSIONS

Restoration of knee joint homeostasis is essential to cruciate ligament recuperation, micro-trauma repair, and remodeling. The nervous and immune systems are intricately involved in this process. Varying combinations of high-intensity training, under-recovery, technostress, and environmental pollutants (including noise) regularly expose many athletically active individuals to factors that abrogate the environment needed for cruciate ligament recuperation, micro-trauma repair, and remodeling. Current sports training practice, lifestyle psychobehaviors, and environmental factors combine to increase both primary non-contact knee injury risk and the nervous and immune system dysregulation that lead to poor sleep, increased anxiety, and poorly regulated hormone and cytokine levels. These factors may create a worst-case scenario leading to poor ligament recuperation, micro-trauma repair, and remodeling. Early recognition and modification of these factors may decrease knee ligament injury rates and improve cruciate ligament repair or reconstruction outcomes.

LEVEL OF EVIDENCE

V.

Aging and Physiological Lessons from Master Athletes

Sedentary aging is often characterized by physical dysfunction and chronic degenerative diseases. In contrast, masters athletes demonstrate markedly greater physiological function and more favorable levels of risk factors for cardiovascular disease, osteoporosis, frailty, and cognitive dysfunction than their sedentary counterparts. In many cases, age-related deteriorations of physiological functions as well as elevations in risk factors that are typically observed in sedentary adults are substantially attenuated or even absent in masters athletes. Older masters athletes possess greater functional capacity at any given age than their sedentary peers. Impressive profiles of older athletes provide insight into what is possible in human aging and place aging back into the domain of "physiology" rather than under the jurisdiction of "clinical medicine." In addition, these exceptional aging athletes can serve as a role model for the promotion of physical activity at all ages. The study of masters athletes has provided useful insight into the positive example of successful aging. To further establish and propagate masters athletics as a role model for our aging society, future research and action are needed. © 2020 American Physiological Society. Compr Physiol 10:261-296, 2020.

The Effects of Well-Rounded Exercise Program on Systemic Biomarkers Related to Cartilage Metabolism

Nonsurgical treatment such as exercise is the preferred method for management of knee osteoarthritis (OA). A combination of aerobic, muscle strengthening, and flexibility exercises is recommended for older adults. However, effects of the exercise intervention on cartilage metabolism remain unclear. This study used biomarkers to investigate the effects of well-rounded exercise program on cartilage metabolism in 42 women (mean age: 59 years). Participants started a weekly supervised exercise program and continued for 12 weeks. Before and after the program, we measured physical performance on the Timed Up-and-Go Test, 3-Minute Walk Test, and 30-Second Chair Stand Test. We collected serum and urine samples at the start of the program until 24 weeks and measured the concentrations of 4 biomarkers related to type II collagen metabolism: serum cartilage type II procollagen carboxy propeptide (sPIICP), urine C-terminal telopeptide of collagen type II (uCTX-II), urine cleavage of type II collagen by collagenases (uC2C), and serum cartilage oligomeric matrix protein (sCOMP). Participants were divided into pre-OA and OA groups based on X-ray findings. The pre-OA group showed significant increases and decreases in sPIICP and uCTX-II concentrations with improved physical performance, respectively. sCOMP concentrations significantly increased in both groups. The exercise also improved physical performance with no detrimental effect on type II collagen metabolism in the OA group. Thus, well-rounded exercise may not only improve physical capacity but also have beneficial effects on type II collagen metabolism, especially in people without radiological OA.

Reconsidering osteoarthritis as a skeletal indicator of age at death

OBJECTIVES

Osteoarthritis (OA) generally increases with age, but it is a complex, multifactorial disease. This study investigated whether obesity, physical activity, and antemortem trauma preclude the use of OA for skeletal age estimation.

MATERIALS AND METHODS

The temporomandibular joint (TMJ) and all appendicular joints were scored for skeletal indicators of OA in 408 modern European-Americans (Bass Collection, TN). Binomial generalized linear models (GLMs) assessed the contributions of self-reported demographic data to OA, including: age; body mass index (BMI); and metabolic values for physical activities. Repeated resampling tested whether observed mean OA scores for joints with trauma consistently exceeded mean scores for unaffected joints. Single-variable GLM probit models were generated for OA presence/absence data in relevant joints.

RESULTS

Age was the only statistically significant predictor of OA in most multivariable GLMs. Occupation and age were both significant predictors of male hand OA; BMI was the only significant predictor of female ankle OA. Trauma significantly affected OA in most joints. Age cut-offs calculated from the single-variable probit models (representing ages of transition to "OA present") ranged from 29.7 to 77.3 years (90%) and 32.7 to 96.6 years (95%), but were problematic for the male TMJ.

DISCUSSION

Ankle OA should not be used to age females; TMJ OA should not be used to age males. For other joints, using OA to inform age estimates appears valid (in absence of antemortem trauma). While skeletal evidence of OA is not a primary age indicator, its presence can refine age ranges and provide essential age data in fragmentary cases.

Autologous Chondrocyte Implantation with Chondrosphere for Treating Articular Cartilage Defects in the Knee: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

Chondrosphere (Spherox) is a form of autologous chondrocyte implantation (ACI). It is licensed for repair of symptomatic articular cartilage defects of the femoral condyle and the patella of the knee with defect sizes up to 10 cm² in adults. In a single technology appraisal (STA) [TA508] undertaken by the National Institute of Health and Care Excellence (NICE), Warwick Evidence was the Evidence Review Group (ERG) invited to independently review the evidence submitted by the manufacturer, Co.Don. The clinical effectiveness data came from their COWISI randomised controlled trial (RCT), which compared Chondrosphere with microfracture (MF). The timing of this appraisal was unfortunate given that MF was no longer the most relevant comparator because NICE had contemporaneously published guidance approving ACI in place of MF. Moreover, the COWISI RCT enrolled mostly patients with small defect sizes. Evidence of clinical effectiveness for Chondrosphere used in people with larger defect size came from another RCT, which compared three doses of Chondrosphere and that by design could not provide evidence comparing Chondrosphere to any other forms of ACI. To estimate the relative clinical performance of Chondrosphere versus other ACI, Co.Don conducted an indirect treatment comparison by network meta-analyses (NMA). The NMA was flawed in that the distribution of population characteristics that are effect modifiers greatly differed across the treatment comparisons of the network. The ERG questioned both the appropriateness of the NMA and the validity of the resulting estimates. Co.Don estimated the cost-effectiveness of Chondrosphere using a lifetime Markov model with all patients receiving the first repair during the first cycle of the model then moving into one of three health states: success, no further repair (NFR), or a second repair, if necessary. Subsequent to the first cycle, those who were a success either remained a success or moved to second repair. All those in NFR remained in NFR. The cost-effectiveness of Chondrosphere compared to other ACI forms relied on the clinical effectiveness estimates of success and failure rates obtained from the company's indirect comparisons, the validity of which the ERG questioned. The company revised cost-effectiveness estimates for Chondrosphere versus MF and for Chondrosphere versus matrix-applied characterised autologous cultured chondrocyte implant (MACI) were £4360 and around £18,000 per quality-adjusted life year gained, respectively. NICE recommended ACI using Chondrosphere for treating symptomatic articular cartilage defects of the femoral condyle and patella of the knee in adults only if certain requirements were met.

Knee problems are common in young adults and associated with physical activity and not obesity: the findings of a cross-sectional survey in a university cohort

Background

Obesity and sedentary behaviour, risk factors for knee osteoarthritis in middle-age, are increasing in younger adults. The objectives of this study were to estimate the prevalence of knee problems in young adults, to characterise these problems and explore the relationship with physical activity, physical inactivity and obesity.

Methods

Presence of knee problems was collected through self-report questionnaire from staff and students of one university aged 18–39; direct measurement of weight and height was taken and activity measured using the International Physical Activity Questionnaire. Twelve-month prevalence of knee problems was estimated. Logistic regression was used to investigate the relationship between knee problems and physical activity levels, sitting time and body mass index.

Results

The prevalence of knee problems was high (31.8% [95% CI 26.9 to 37.2%]) among the 314 participants; knee pain was the most common dominant symptom (65%). Only high physical activity levels (OR 2.6 [95% CI 1.4–4.9]) and mental distress (OR 2.3 [95% CI 1.2–4.6]) were independent risk factors for knee problems.

Conclusions

Knee problems were common among young adults, who were staff and students of a university. With increasing obesity prevalence, populations are being encouraged to become more active. More attention may need to be paid towards prevention of knee problems in such programmes, and further research is warranted.

Does vitamin D deficiency influence the incidence and progression of knee osteoarthritis? - A literature review

OBJECTIVES

Vitamin D has been believed to have a bearing in the pathogenesis of knee osteoarthritis (OA). This study was done to search the literature and review the correlation between vitamin D levels in knee OA in the adult population and the outcome of vitamin D supplementation in knee OA.

METHODS

An exhaustive search of Pub Med and Cochrane library database was done with keywords vitamin D, knee and osteoarthritis for a period from Jan 2005 to December 2015. All Randomized Control Trials (RCT), Cohort, Case-control, cross-sectional studies were included in the present systematic review.

RESULTS

The search resulted in a total of 86 studies; out of which 11 studies were included in the current review. There were two Randomized Control Trial (RCT), one case-control, four cross-sectional and four cohort studies. These studies comprised of a total of 5137 participants (ranging from 46 to 1248) Our results suggested there was a moderate evidence of positive association in vitamin D deficiency (VDD) and progression of radiographic OA (ROA), as assessed by Kellgren and Lawrence (KL) grading. However, VDD was not associated with the incidence of ROA and MRI-detected change in focal cartilage defect. However, this study has a limited evidence for a positive correlation in VDD and the cartilage volume loss. There was also limited evidence showing no role of vitamin D therapy in reducing cartilage volume loss and knee pain in Knee OA.

CONCLUSION

The VDD is common and has been associated with knee OA, in an adult population. However, there is still inconsistent evidence regarding the prevention of incidence and progression of ROA after vitamin D therapy. There is a need for multicentric and well-conducted randomized studies with larger samples to conclude the positive effect of Vitamin D therapy.

Validation of the Acetabulum As a Skeletal Indicator of Age at Death in Modern European-Americans

Progressive changes in the acetabulum have been used in modern skeletal age estimation, but they have not been completely understood. If their age correlations are weakened by the influence of factors like physical activity and obesity, acetabular changes should not be used for age estimation. To investigate their utility for aging, the acetabular variables of Rissech et al. (2006) were analyzed in 409 modern European-Americans (Bass Collection, Tennessee). Correlation tests assessed potential associations between acetabular data, osteoarthritis scores (collected per Jurmain, 1990), and documented demographic information (age, body mass index [BMI], metabolic intensity of physical activities). Acetabular changes had statistically significant, positive correlations with osteoarthritis (p < 0.001 in most joints/regions) and age (p < 0.001), indicating their degenerative nature and relevance for age estimation. Acetabular changes showed no associations with BMI or metabolic values, suggesting resistance to obesity and activity effects. These results suggest that acetabular degeneration is a valid skeletal age-at-death indicator.

Effects of long-term exercise therapy on knee joint structure in people with knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVE

To investigate effects of long-term exercise therapy for people with knee osteoarthritis (OA) on radiographic disease severity and cartilage integrity (primary outcomes) as well as severity of bone marrow lesions (BMLs), synovitis and/or effusion (secondary outcomes).

METHODS

We sourced randomized controlled trials in people with clinical and/or radiographic OA investigating the effect of land-based exercise therapy of > 6 months on radiographic disease severity and magnetic resonance imaging outcomes of cartilage integrity (morphology or composition) as well as BML, synovitis and/or effusion severity, when compared to no exercise. Two independent reviewers extracted data and assessed risk of bias. Random-effects meta-analysis was used to pool standardised mean differences (SMD) (95% confidence intervals (CI)) or odds ratios (OR) (95% CI) and estimate heterogeneity (I², %). Quality of the pooled body of evidence was rated implementing the GRADE approach. Studies unsuitable for meta-analysis were summarized in a best-evidence synthesis.

RESULTS

Meta-analysis showed moderate quality evidence of no treatment effect on tibiofemoral radiographic disease severity ((SMD) 95% (CI): 0.06 (-0.07, 0.20), I²= 0%) and low-quality evidence of no effect on tibiofemoral cartilage morphology (SMD (95%): 0.06 (-0.20, 0.36), I²= 0%). Low quality evidence revealed no treatment effect on the odds of change in synovitis ((OR) (95% CI): 0.90 (0.51,1.60), I²= 0%) and effusion ((OR (95% CI): 0.88 (0.64, 1.20), I²= 0%), but greater odds of tibiofemoral BMLs worsening (OR (95% CI): 1.90 (1.11, 3.26), I²= 0%). In best-evidence synthesis, limited evidence was found for changes in patellar cartilage composition following exercise in women with mild knee OA compared to no exercise, but not for tibiofemoral cartilage.

CONCLUSION

Long-term exercise therapy did not change tibiofemoral radiographic disease severity, cartilage morphology or synovitis/effusion, but may slightly increase the likelihood for increased BML severity. Overall, meta-analysis findings were limited in directness and precision and restricted to relatively imprecise effect estimates in people who were obese on average. Limited evidence suggested some protective effects on patellar cartilage composition.

Potential Effect Modifiers of the Association Between Physical Activity Patterns and Joint Symptoms in Middle-Aged Women

OBJECTIVE

To examine whether body mass index (BMI), menopausal status, and hormone therapy (HT) use modify the association between physical activity (PA) patterns throughout middle age and the incidence and prevalence of joint symptoms in women in later middle age.

METHODS

Data were from 6,661 participants (born 1946-1951) in the Australian Longitudinal Study on Women's Health. Surveys, with questions on joint pain and stiffness, PA, height and weight, menopausal symptoms, and HT use, were completed every 3 years from 1998 to 2010. PA patterns were defined as none or low, low or meeting guidelines, fluctuating, or meeting guidelines at all times (reference pattern). Logistic regression was used to examine the association between PA patterns and prevalent (in 2010) and cumulative incident (1998-2010) joint symptoms and effect modification by patterns in BMI, menopausal status, and HT.

RESULTS

The groups representing fluctuating PA (odds ratio [OR] 1.34 [99% confidence interval (99% CI) 1.04-1.72]) and no or low PA (OR 1.60 [99% CI 1.08-2.35]) had higher odds of incident joint symptoms than those described as meeting guidelines at all times. Stratification by BMI showed that this association was statistically significant in the obese group only. No evidence for effect modification by menopausal status or HT use was found. The findings were similar for prevalent joint symptoms.

CONCLUSION

Maintaining at least low levels of PA throughout middle age was associated with a lower prevalence and incidence of joint symptoms later in life. This apparent protective effect of PA on joint symptoms was stronger in obese women than in under- or normal-weight women, and not related to menopause or HT status.

Living with osteoarthritis is a balancing act: an exploration of patients' beliefs about knee pain

Background

This study aimed to explore the beliefs of people with knee osteoarthritis (OA) about the disease, and how these beliefs had formed and what impact these beliefs had on activity participation, health behaviour, and self-management.

Methods

Semi-structured interviews were conducted with 13 people with knee OA recruited from general practices, community physiotherapy clinics, and public advertisements in two provinces of New Zealand. Data were analysed using Interpretive Description.

Results

Two key themes emerged. 1) Knowledge: certainty and uncertainty described participants’ strong beliefs about anatomical changes in their knee. Participants’ beliefs in a biomechanical model of progressive joint degradation often appeared to originate within clinical encounters and from literal interpretation of the term ‘wear and tear’. These beliefs led to uncertainty regarding interpretation of daily symptoms and participants’ ability to influence the rate of decline and certainty that joint replacement surgery represented the only effective solution to fix the damaged knee. 2) Living with OA described broader perspectives of living with OA and the perceived need to balance competing values and risks when making decisions about activity participation, medication, attentional focus, accessing care, and making the most of today without sabotaging tomorrow. Misunderstandings about knee OA negatively impacted on activity participation, health behaviours, and self-management decisions.

Conclusion

Biomechanical models of OA reduced participant exploration of management options and underpinned a perceived need to balance competing values. Improved information provision to people with knee OA could help guide positive health behaviour and self-management decisions and ensure these decisions are grounded in current evidence.

Electronic supplementary material

The online version of this article (10.1186/s41927-018-0023-x) contains supplementary material, which is available to authorized users.

Autologous chondrocyte implantation in the knee: systematic review and economic evaluation

BACKGROUND

The surfaces of the bones in the knee are covered with articular cartilage, a rubber-like substance that is very smooth, allowing frictionless movement in the joint and acting as a shock absorber. The cells that form the cartilage are called chondrocytes. Natural cartilage is called hyaline cartilage. Articular cartilage has very little capacity for self-repair, so damage may be permanent. Various methods have been used to try to repair cartilage. Autologous chondrocyte implantation (ACI) involves laboratory culture of cartilage-producing cells from the knee and then implanting them into the chondral defect.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of ACI in chondral defects in the knee, compared with microfracture (MF).

DATA SOURCES

A broad search was done in MEDLINE, EMBASE, The Cochrane Library, NHS Economic Evaluation Database and Web of Science, for studies published since the last Health Technology Assessment review.

REVIEW METHODS

Systematic review of recent reviews, trials, long-term observational studies and economic evaluations of the use of ACI and MF for repairing symptomatic articular cartilage defects of the knee. A new economic model was constructed. Submissions from two manufacturers and the ACTIVE (Autologous Chondrocyte Transplantation/Implantation Versus Existing Treatment) trial group were reviewed. Survival analysis was based on long-term observational studies.

RESULTS

Four randomised controlled trials (RCTs) published since the last appraisal provided evidence on the efficacy of ACI. The SUMMIT (Superiority of Matrix-induced autologous chondrocyte implant versus Microfracture for Treatment of symptomatic articular cartilage defects) trial compared matrix-applied chondrocyte implantation (MACI^®) against MF. The TIG/ACT/01/2000 (TIG/ACT) trial compared ACI with characterised chondrocytes against MF. The ACTIVE trial compared several forms of ACI against standard treatments, mainly MF. In the SUMMIT trial, improvements in knee injury and osteoarthritis outcome scores (KOOSs), and the proportion of responders, were greater in the MACI group than in the MF group. In the TIG/ACT trial there was improvement in the KOOS at 60 months, but no difference between ACI and MF overall. Patients with onset of symptoms < 3 years' duration did better with ACI. Results from ACTIVE have not yet been published. Survival analysis suggests that long-term results are better with ACI than with MF. Economic modelling suggested that ACI was cost-effective compared with MF across a range of scenarios.

LIMITATIONS

The main limitation is the lack of RCT data beyond 5 years of follow-up. A second is that the techniques of ACI are evolving, so long-term data come from trials using forms of ACI that are now superseded. In the modelling, we therefore assumed that durability of cartilage repair as seen in studies of older forms of ACI could be applied in modelling of newer forms. A third is that the high list prices of chondrocytes are reduced by confidential discounting. The main research needs are for longer-term follow-up and for trials of the next generation of ACI.

CONCLUSIONS

The evidence base for ACI has improved since the last appraisal by the National Institute for Health and Care Excellence. In most analyses, the incremental cost-effectiveness ratios for ACI compared with MF appear to be within a range usually considered acceptable. Research is needed into long-term results of new forms of ACI.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013083.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Mapping the spatiotemporal evolution of solute transport in articular cartilage explants reveals how cartilage recovers fluid within the contact area during sliding

The interstitial fluid within articular cartilage shields the matrix from mechanical stresses, reduces friction and wear, enables biochemical processes, and transports solutes into and out of the avascular extracellular matrix. The balanced competition between fluid exudation and recovery under load is thus critical to the mechanical and biological functions of the tissue. We recently discovered that sliding alone can induce rapid solute transport into buried cartilage contact areas via a phenomenon termed tribological rehydration. In this study, we use in situ confocal microscopy measurements to track the spatiotemporal propagation of a small neutral solute into the buried contact area to clarify the fluid mechanics underlying the tribological rehydration phenomenon. Sliding experiments were interrupted by periodic static loading to enable scanning of the entire contact area. Spatiotemporal patterns of solute transport combined with tribological data suggested pressure driven flow through the extracellular matrix from the contact periphery rather than into the surface via a fluid film. Interestingly, these testing interruptions also revealed dynamic, repeatable and history-independent fluid loss and recovery processes consistent with those observed in vivo. Unlike the migrating contact area, which preserves hydration by moving faster than interstitial fluid can flow, our results demonstrate that the stationary contact area can maintain and actively recover hydration through a dynamic competition between load-induced exudation and sliding-induced recovery. The results demonstrate that sliding contributes to the recovery of fluid and solutes by cartilage within the contact area while clarifying the means by which it occurs.

Knee osteoarthritis has doubled in prevalence since the mid-20th century

Knee osteoarthritis (OA) is believed to be highly prevalent today because of recent increases in life expectancy and body mass index (BMI), but this assumption has not been tested using long-term historical or evolutionary data. We analyzed long-term trends in knee OA prevalence in the United States using cadaver-derived skeletons of people aged ≥50 y whose BMI at death was documented and who lived during the early industrial era (1800s to early 1900s; n = 1,581) and the modern postindustrial era (late 1900s to early 2000s; n = 819). Knee OA among individuals estimated to be ≥50 y old was also assessed in archeologically derived skeletons of prehistoric hunter-gatherers and early farmers (6000-300 B.P.; n = 176). OA was diagnosed based on the presence of eburnation (polish from bone-on-bone contact). Overall, knee OA prevalence was found to be 16% among the postindustrial sample but only 6% and 8% among the early industrial and prehistoric samples, respectively. After controlling for age, BMI, and other variables, knee OA prevalence was 2.1-fold higher (95% confidence interval, 1.5-3.1) in the postindustrial sample than in the early industrial sample. Our results indicate that increases in longevity and BMI are insufficient to explain the approximate doubling of knee OA prevalence that has occurred in the United States since the mid-20th century. Knee OA is thus more preventable than is commonly assumed, but prevention will require research on additional independent risk factors that either arose or have become amplified in the postindustrial era.

The Role of Athletic Trainers in Preventing and Managing Posttraumatic Osteoarthritis in Physically Active Populations: a Consensus Statement of the Athletic Trainers' Osteoarthritis Consortium

OBJECTIVE

  To provide athletic trainers with a fundamental understanding of the pathogenesis and risk factors associated with the development of posttraumatic osteoarthritis (PTOA) as well as the best current recommendations for preventing and managing this condition.

BACKGROUND

  Posttraumatic osteoarthritis, or osteoarthritis that develops secondary to joint injury, accounts for approximately 5.5 million US cases annually. A young athlete with a joint injury is at high risk for PTOA before the age of 40, which could lead to the patient living more than half of his or her life with a painful and disabling disorder. Given our frequent contact with physically active people who often sustain traumatic joint injuries, athletic trainers are in a unique position to help prevent and manage PTOA. We can, therefore, regularly monitor joint health in at-risk patients and implement early therapies as necessary.

RECOMMENDATIONS

  The recommendations for preventing and managing PTOA are based on the best available evidence. Primary injury prevention, self-management strategies, maintenance of a healthy body weight, and an appropriate level of physical activity should be encouraged among those at risk for PTOA after acute traumatic joint injury. Education of athletic trainers and patients regarding PTOA is also critical for effective prevention and management of this disease.

Running and Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

Osteoarthritis (OA) is a chronic condition characterized by pain, impaired function, and reduced quality of life. A number of risk factors for knee OA have been identified, such as obesity, occupation, and injury. The association between knee OA and physical activity or particular sports such as running is less clear. Previous reviews, and the evidence that informs them, present contradictory or inconclusive findings.

PURPOSE

This systematic review aimed to determine the association between running and the development of knee OA.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Four electronic databases were searched, along with citations in eligible articles and reviews and the contents of recent journal issues. Two reviewers independently screened the titles and abstracts using prespecified eligibility criteria. Full-text articles were also independently assessed for eligibility. Eligible studies were those in which running or running-related sports (eg, triathlon or orienteering) were assessed as a risk factor for the onset or progression of knee OA in adults. Relevant outcomes included (1) diagnosis of knee OA, (2) radiographic markers of knee OA, (3) knee joint surgery for OA, (4) knee pain, and (5) knee-associated disability. Risk of bias was judged by use of the Newcastle-Ottawa scale. A random-effects meta-analysis was performed with case-control studies investigating arthroplasty.

RESULTS

After de-duplication, the search returned 1322 records. Of these, 153 full-text articles were assessed; 25 were eligible, describing 15 studies: 11 cohort (6 retrospective) and 4 case-control studies. Findings of studies with a diagnostic OA outcome were mixed. Some radiographic differences were observed in runners, but only at baseline within some subgroups. Meta-analysis suggested a protective effect of running against surgery due to OA: pooled odds ratio 0.46 (95% CI, 0.30-0.71). The I² was 0% (95% CI, 0%-73%). Evidence relating to symptomatic outcomes was sparse and inconclusive.

CONCLUSION

With this evidence, it is not possible to determine the role of running in knee OA. Moderate- to low-quality evidence suggests no association with OA diagnosis, a positive association with OA diagnosis, and a negative association with knee OA surgery. Conflicting results may reflect methodological heterogeneity. More evidence from well-designed, prospective studies is needed to clarify the contradictions.

The Effect of Widespread Pain on Knee Pain Worsening, Incident Knee Osteoarthritis (OA), and Incident Knee Pain: The Multicenter OA (MOST) Study

OBJECTIVE

Whether widespread pain (WSP) affects the risk of developing knee pain or knee osteoarthritis (OA) is unknown and could enhance understanding of pain mechanisms in OA.

METHODS

Subjects from the Multicenter OA (MOST) study, a US National Institutes of Health-funded prospective cohort of older adults with or at risk of knee OA, were characterized regarding WSP, defined as pain above and below the waist on both sides of the body and axially using a standard homunculus, excluding knee pain at 60 months (baseline). Followup occurred 2 years later. We assessed the relation of WSP to odds of knee pain worsening (≥ 2-point increase in the Western Ontario and McMaster Universities Arthritis Index pain subscale) using logistic regression, and to odds of incident radiographic knee OA (ROA; Kellgren-Lawrence arthritis scale ≥ grade 2 of either knee among those free of ROA at baseline) and incident consistent frequent knee pain (CFKP; knee pain on most days during the past month among participants free of knee pain at baseline) in 1 or both knees using multinomial regression adjusting for potential confounders.

RESULTS

There were 1752 participants available for analysis [mean age (SD) 67.0 yrs (7.7), body mass index 30.5 kg/m2 (5.9), 59% women]. Baseline presence of WSP was not associated with worsened knee pain (adjusted OR 1.15, 95% CI 0.89-1.48, p = 0.30), ROA (adjusted OR 0.86, 95% CI 0.46-1.63, p = 0.65), or incident CFKP (adjusted OR 1.69, 95% CI 0.96-2.96, p = 0.07).

CONCLUSION

WSP was not significantly associated with worsening knee pain, incident ROA, or CFKP. Development of knee pain and ROA does not appear to be influenced by underlying WSP.

Do early life factors affect the development of knee osteoarthritis in later life: a narrative review

Osteoarthritis (OA) mainly affects older populations; however, it is possible that early life factors contribute to the development of OA in later life. The aim of this review is to describe the association between childhood or early adulthood risk factors and knee pain, structural imaging markers and development of knee OA in later life. A narrative overview of the literature synthesising the findings of literature retrieved from searches of computerised databases and manual searches was conducted. We found that only a few studies have explored the long-term effect of childhood or early adulthood risk factors on the markers of joint health that predispose people to OA or joint symptoms. High body mass index (BMI) and/or overweight status from childhood to adulthood were independently related to knee pain and OA in later life. The findings regarding the association between strenuous physical activity and knee structures in young adults are still conflicting. However, a favourable effect of moderate physical activity and fitness on knee structures is reported. Childhood physical activity and performance measures had independent beneficial effects on knee structures including knee cartilage in children and young adults. Anterior knee pain syndrome in adolescence could lead to the development of patellofemoral knee OA in the late 40s. Furthermore, weak evidence suggests that childhood malalignment, socioeconomic status and physical abuse are associated with OA in later life. The available evidence suggests that early life intervention may prevent OA in later life.

The immediate effect of long-distance running on T2 and T2* relaxation times of articular cartilage of the knee in young healthy adults at 3.0 T MR imaging

OBJECTIVE

To quantitatively assess the immediate effect of long-distance running on T2 and T2* relaxation times of the articular cartilage of the knee at 3.0 T in young healthy adults.

METHODS

30 healthy male adults (18-31 years) who perform sports at an amateur level underwent an initial MRI at 3.0 T with T2 weighted [16 echo times (TEs): 9.7-154.6 ms] and T2* weighted (24 TEs: 4.6-53.6 ms) relaxation measurements. Thereafter, all participants performed a 45-min run. After the run, all individuals were immediately re-examined. Data sets were post-processed using dedicated software (ImageJ; National Institute of Health, Bethesda, MD). 22 regions of interest were manually drawn in segmented areas of the femoral, tibial and patellar cartilage. For statistical evaluation, Pearson product-moment correlation coefficients and confidence intervals were computed.

RESULTS

Mean initial values were 35.7 ms for T2 and 25.1 ms for T2*. After the run, a significant decrease in the mean T2 and T2* relaxation times was observed for all segments in all participants. A mean decrease of relaxation time was observed for T2 with 4.6 ms (±3.6 ms) and for T2* with 3.6 ms (±5.1 ms) after running.

CONCLUSION

A significant decrease could be observed in all cartilage segments for both biomarkers. Both quantitative techniques, T2 and T2*, seem to be valuable parameters in the evaluation of immediate changes in the cartilage ultrastructure after running.

ADVANCES IN KNOWLEDGE

This is the first direct comparison of immediate changes in T2 and T2* relaxation times after running in healthy adults.

Association of Physical Activity Measured by Accelerometer, Knee Joint Abnormalities, and Cartilage T2 Measurements Obtained From 3T Magnetic Resonance Imaging: Data From the Osteoarthritis Initiative

OBJECTIVE

To study the cross-sectional association between physical activity measured with an accelerometer, structural knee abnormalities, and cartilage T2 values assessed with 3T magnetic resonance imaging (MRI).

METHODS

We included 274 subjects from the Osteoarthritis Initiative cohort without definite radiographic osteoarthritis (Kellgren/Lawrence grades 0 and 1) and with at most mild pain, stiffness, and functional limitation in the study knee (Western Ontario and McMaster Universities Osteoarthritis Index scale 0-1), which had not limited their activity due to knee pain. Physical activity was measured over 7 days with an ActiGraph GT1M accelerometer. Subjects were categorized by quartile of physical activity based on the average daily minutes of moderate to vigorous physical activity (mv-PA). MRI images of the right knee (at 48-month visit) were assessed for structural abnormalities using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) and for T2 relaxation times derived from segmented cartilage of 4 femorotibial regions and the patella. WORMS grades and T2 measurements were compared between activity quartiles using a linear regression model. Covariates included age, sex, body mass index, knee injury, family history of knee replacement, knee symptoms, hip and ankle pain, and daily wear time of the accelerometer.

RESULTS

Higher mv-PA was associated with increased severity (P = 0.0087) and number of lesions of the medial meniscus (P = 0.0089) and with severity of bone marrow edema lesions (P = 0.0053). No association between cartilage lesions and mv-PA was found. T2 values of cartilage (loss, damage, and abnormalities) tended to be greater in the higher quartiles of mv-PA, but the differences were nonsignificant.

CONCLUSION

In knees without radiographic osteoarthritis in subjects with no or mild knee pain, higher physical activity levels were associated with increases in meniscal and bone marrow edema pattern lesions.

Non-surgical treatments for the management of early osteoarthritis

Non-surgical treatments are usually the first choice for the management of knee degeneration, especially in the early osteoarthritis (OA) phase when no clear lesions or combined abnormalities need to be addressed surgically. Early OA may be addressed by a wide range of non-surgical approaches, from non-pharmacological modalities to dietary supplements and pharmacological therapies, as well as physical therapies and novel biological minimally invasive procedures involving injections of various substances to obtain a clinical improvement and possibly a disease-modifying effect. Numerous pharmaceutical agents are able to provide clinical benefit, but no one has shown all the characteristic of an ideal treatment, and side effects have been reported at both systemic and local level. Patients and physicians should have realistic outcome goals in pharmacological treatment, which should be considered together with other conservative measures. Among these, exercise is an effective conservative approach, while physical therapies lack literature support. Even though a combination of these therapeutic options might be the most suitable strategy, there is a paucity of studies focusing on combining treatments, which is the most common clinical scenario. Further studies are needed to increase the limited evidence on non-surgical treatments and their combination, to optimize indications, application modalities, and results with particular focus on early OA. In fact, most of the available evidence regards established OA. Increased knowledge about degeneration mechanisms will help to better target the available treatments and develop new biological options, where preliminary results are promising, especially concerning early disease phases. Specific treatments aimed at improving joint homoeostasis, or even counteracting tissue damage by inducing regenerative processes, might be successful in early OA, where tissue loss and anatomical changes are still at very initial stages.

Physical Activity Patterns Among Older Adults With and Without Knee Osteoarthritis in Six European Countries

OBJECTIVE

To investigate patterns of physical activity in older adults with knee osteoarthritis (OA) compared to older adults without knee OA across 6 European countries. We expect country-specific differences in the physical activity levels between persons with knee OA compared to persons without knee OA. A varying degree of physical activity levels across countries would express a facilitating or impeding influence of the social, environmental, and other contextual factors on a physically active lifestyle.

METHODS

Baseline cross-sectional data from the European Project on Osteoarthritis were analyzed. In total, 2,551 participants from 6 European countries (Germany, Italy, The Netherlands, Spain, Sweden, and the UK) were included.

RESULTS

Participants with knee OA were less likely to follow physical activity recommendations and had poorer overall physical activity profiles than those without knee OA (mean 62.9 versus 81.5 minutes/day, respectively; P = 0.015). The magnitude of this difference varied across countries. Detailed analysis showed that low physical activity levels in persons with knee OA could be attributed to less everyday walking time (odds ratio 1.31, 95% confidence interval 1.07-1.62).

CONCLUSION

This study highlighted the fact that having knee OA is associated with a varying degree of physical activity patterns in different countries. This national variation implies that low levels of physical activity among persons with knee OA cannot be explained exclusively by individual or disease-specific factors, but that social, environmental, and other contextual factors should also be taken into account.

Association of physical activity and physical performance with tibial cartilage volume and bone area in young adults

Introduction

Physical activity has been recommended to patients with knee osteoarthritis for improving their symptoms. However, it is still controversial if physical activity has effects on joint structures including cartilage volume. The aim of this study was to describe the associations between physical activity and performance measured 5 years prior and tibial cartilage volume and bone area in young adults.

Methods

Subjects broadly representative of the Australian population (n = 328, aged 31–41 years, female 47.3 %) were selected from the Childhood Determinants of Adult Health study. They underwent T1-weighted fat-suppressed magnetic resonance imaging (MRI) scans of their knees. Tibial bone area and cartilage volume were measured from MRI. Physical activity (measured using long international physical activity questionnaire (IPAQ)) and performance measures (long jump, leg muscle strength, physical work capacity (PWC₁₇₀)) were measured 5 years prior.

Results

In multivariable analyses, total physical activity (min/week) (β: 0.30 mm³, 95 % CI: 0.13,0.47), vigorous (β: 0.54 mm³, 95 % CI: 0.13,0.94), moderate (β: 0.34 mm³, 95 % CI: 0.01,0.67), walking (β: 0.40 mm³, 95 % CI: 0.07,0.72) and IPAQ category (β: 182.9 mm³, 95 % CI: 51.8,314.0) were positively associated with total tibial cartilage volume but not tibial bone area. PWC₁₇₀, long jump and leg muscle strength were positively and significantly associated with both total tibial cartilage volume and total tibial bone area; and the associations with tibial cartilage volume decreased in magnitude but remained significant for PWC₁₇₀ and long jump after further adjustment for tibial bone area.

Conclusion

While tibial bone area is affected only by physical performance, total tibial cartilage volume can be influenced by both physical activity and performance in younger adults. The clinical significance suggests a beneficial effect for cartilage but the bone area association was restricted to performance suggesting other factors rather than physical activity may be important.

Is Participation in Certain Sports Associated With Knee Osteoarthritis? A Systematic Review

OBJECTIVE

  Information regarding the relative risks of developing knee osteoarthritis (OA) as a result of sport participation is critical for shaping public health messages and for informing knee-OA prevention strategies. The purpose of this systematic review was to investigate the association between participation in specific sports and knee OA.

DATA SOURCES

  We completed a systematic literature search in September 2012 using 6 bibliographic databases (PubMed; Ovid MEDLINE; Journals@Ovid; American College of Physicians Journal Club; Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Review, Database of Abstracts of Reviews of Effects; and Ovid HealthStar), manual searches (4 journals), and reference lists (56 articles).

STUDY SELECTION

  Studies were included if they met the following 4 criteria: (1) an aim was to investigate an association between sport participation and knee OA; (2) the outcome measure was radiographic knee OA, clinical knee OA, total knee replacement, self-reported diagnosis of knee OA, or placement on a waiting list for a total knee replacement; (3) the study design was case control or cohort; and (4) the study was written in English. Articles were excluded if the study population had an underlying condition other than knee OA.

DATA EXTRACTION

  One investigator extracted data (eg, group descriptions, knee OA prevalence, source of nonexposed controls).

DATA SYNTHESIS

  The overall knee-OA prevalence in sport participants (n = 3759) was 7.7%, compared with 7.3% among nonexposed controls (referent group n = 4730, odds ratio [OR] = 1.1). Specific sports with a significantly higher prevalence of knee OA were soccer (OR = 3.5), elite-level long-distance running (OR = 3.3), competitive weight lifting (OR = 6.9), and wrestling (OR = 3.8). Elite-sport (soccer or orienteering) and nonelite-sport (soccer or American football) participants without a history of knee injury had a greater prevalence of knee OA than nonexposed participants.

CONCLUSIONS

  Participants in soccer (elite and nonelite), elite-level long-distance running, competitive weight lifting, and wrestling had an increased prevalence of knee OA and should be targeted for risk-reduction strategies.