Is There an Association Between a History of Running and Symptomatic Knee Osteoarthritis? A Cross-Sectional Study From the Osteoarthritis Initiative

Strength Training Is Associated With Less Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

We aimed to evaluate the relationship of a history of strength training with symptomatic and structural outcomes of knee osteoarthritis (OA).

METHODS

This study was a retrospective, cross-sectional study within the Osteoarthritis Initiative (OAI), a multicenter prospective longitudinal observational study. Data were collected at four OAI clinical sites: Memorial Hospital of Rhode Island, the Ohio State University, the University of Pittsburgh, and the University of Maryland/Johns Hopkins. The study included 2,607 participants with complete data on strength training, knee pain, and radiographic evidence of knee OA (male, 44.2%; mean ± SD age 64.3 ± 9.0 years; mean ± SD body mass index 28.5 ± 4.9 kg/m2 ). We used a self-administered questionnaire at the 96-month OAI visit to evaluate the exposure of strength training participation during four time periods throughout a participant's lifetime (ages 12-18, 19-34, 35-49, and ≥50 years old). The outcomes (dependent variables) were radiographic OA (ROA), symptomatic radiographic OA (SOA), and frequent knee pain.

RESULTS

The fully adjusted odds ratios (95% confidence interval) for frequent knee pain, ROA, and SOA among those who participated in strength training any time in their lives were 0.82 (0.68-0.97), 0.83 (0.70-0.99), and 0.77 (0.63-0.94), respectively. Findings were similar when looking at the specific age ranges.

CONCLUSION

Strength training is beneficial for future knee health, counteracting long-held assumptions that strength training has adverse effects.

Foot Strike Run Retraining for Patients With Patellofemoral Chondral Defects: A Case Series

Military service members (SMs) demonstrate high rates of patellofemoral chondral defects (PFCDs) that are difficult to diagnosis and, if untreated, result in a cascade of events eventually leading to osteoarthritis. Running is an essential occupational task for SMs; however, there is little evidence regarding techniques to maintain running ability in individuals with cartilage defects. The purpose of this case series was to assess the clinical application of foot strike run retraining in patients with PFCDs. This case series included two active duty U.S. Marine Corps SMs who presented to outpatient physical therapy with PFCD, diagnosed via MRI. Both patients attended eight foot strike run retraining sessions. Running mechanics and patient-reported outcomes were recorded pre-training, post-training, and at a 1-month follow-up visit. Both patients successfully converted their strike pattern from a rearfoot to a non-rearfoot strike pattern with training and retained this strategy at 1-month follow-up. Post-intervention, both patients demonstrated increased running tolerance, and improvements in Numeric Pain Rating Scale and Lower Extremity Functional Scale scores. Biomechanical analysis showed that both patients demonstrated a 63% to 70% reduction in average and peak vertical ground reaction force loading rates post-treatment. Modification of foot strike pattern from rear to non-rearfoot strike during running for individuals with PFCD can reduce the magnitude of impact loading, which potentially limits disease progression. These findings suggest that foot strike run retraining may be a feasible strategy to reduce pain and improve function in SMs with PFCD who are required to run for occupational responsibilities.

Effects of Running on the Development of Knee Osteoarthritis: An Updated Systematic Review at Short-Term Follow-up

Background

Some studies have suggested that running increases the risk of knee osteoarthritis (OA), while others believe it serves a protective function.

Purpose

To perform an updated systematic review of the literature to determine the effects of running on the development of knee OA.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was performed by searching the PubMed, Cochrane Library, and Embase databases to identify studies evaluating the effect of cumulative running on the development of knee OA or chondral damage based on imaging and/or patient-reported outcomes (PROs). The search terms used were "knee AND osteoarthritis AND (run OR running OR runner)." Patients were evaluated based on plain radiographs, magnetic resonance imaging (MRI), and PROs (presence of knee pain, Health Assessment Questionnaire-Disability Index, and the Knee injury and Osteoarthritis Outcome Score).

Results

Seventeen studies (6 level 2 studies, 9 level 3 studies, and 2 level 4 studies), with 7194 runners and 6947 nonrunners, met the inclusion criteria. The mean follow-up time was 55.8 months in the runner group and 99.7 months in the nonrunner group. The mean age was 56.2 years in the runner group and 61.6 years in the nonrunner group. The overall percentage of men was 58.5%. There was a significantly higher prevalence of knee pain in the nonrunner group (P < .0001). Although 1 study found a significantly higher prevalence of osteophytes in the tibiofemoral (TF) and patellofemoral (PF) joints within the runner group, multiple studies found no significant differences in the prevalence of radiographic knee OA (based on TF/PF joint-space narrowing or Kellgren-Lawrence grade) or cartilage thickness on MRI between runners and nonrunners (P > .05). One study found a significantly higher risk of knee OA progressing to total knee replacement among nonrunners (4.6% vs 2.6%; P = .014).

Conclusion

In the short term, running is not associated with worsening PROs or radiological signs of knee OA and may be protective against generalized knee pain.

Is running good or bad for your knees? A systematic review and meta-analysis of cartilage morphology and composition changes in the tibiofemoral and patellofemoral joints

BACKGROUND

The general health benefits of running are well-established, yet concern exists regarding the development and progression of osteoarthritis.

AIM

To systematically review the immediate (within 20 min) and delayed (20 min-48 h) effect of running on hip and knee cartilage, as assessed using magnetic resonance imaging (MRI).

METHOD

Studies using MRI to measure change in hip or knee cartilage within 48 h pre- and post-running were identified. Risk of bias was assessed using a modified Newcastle-Ottawa Scale. Percentage change in cartilage outcomes were estimated using random-effects meta-analysis. Certainty of evidence was evaluated with the Grading of Recommendations Assessment, Development and Evaluation tool.

RESULTS

Twenty-four studies were included, evaluating 446 knees only. One third of studies were low risk of bias. Knee cartilage thickness and volume decreased immediately after running, with declines ranging from 3.3% (95% confidence interval [CI]: 2.6%, 4.1%) for weight-bearing femoral cartilage volume to 4.9% (95% CI: 4.43.6%, 6.2%) for patellar cartilage volume. T1ρ and T2 relaxation times were also reduced immediately after running, with the largest decline being 13.1% (95% CI: -14.4%, -11.7%) in femoral trochlear cartilage. Tibiofemoral cartilage T2 relaxation times recovered to baseline levels within 91 min. Existing cartilage defects were unchanged within 48 h post-run.

CONCLUSIONS

There is very low certainty evidence that running immediately decreases the thickness, volume, and relaxation times of patellofemoral and tibiofemoral cartilage. Hip cartilage changes are unknown, but knee changes are small and appear transient suggesting that a single bout of running is not detrimental to knee cartilage.

Is there a mitochondrial DNA haplogroup connection between osteoarthritis and elite athletes? A narrative review

Elite athletes are at greater risk of joint injuries linked to the subsequent risk of developing osteoarthritis (OA). Genetic factors such as mitochondrial (mt) DNA haplogroups have been associated with the incidence/progression of OA and athletic performance. This review highlights an area not yet addressed: is there a common pattern in the mtDNA haplogroups for OA occurrence in individuals and elite athletes of populations of the same descent? Haplotypes J and T confer a decreased risk of OA in Caucasian/European descent, while H and U increase this risk. Both J and T haplogroups are under-represented in Caucasian/European individuals and endurance athletes with OA, but power athletes showed a greater percentage of the J haplogroup. Caucasian/European endurance athletes had a higher percentage of haplogroup H, which is associated with increased athletic performance. In a Chinese population, haplogroup G appears to increase OA susceptibility and is over-represented in Japanese endurance athletes. In contrast, in Koreans, haplogroup B had a higher frequency of individuals with OA but was under-represented in the endurance athlete population. For Caucasian endurance athletes, it would be interesting to evaluate if those carrying haplotype H would be at an increased risk of accelerated OA, as well as the haplogroup G in Chinese and Japanese endurance athletes. The reverse might be studied for the Korean descent for haplogroup B. Knowledge of such genetic data could be used as a preliminary diagnosis to identify individuals at high risk of OA, adding prognostic information and assisting in personalising the early management of both populations.

Osteoarthritis Risks and Sports: An Evidence-based Systematic Review

PURPOSE

Regular sports activities are associated with multiple physical and psychological health benefits. However, sports also may lead to injuries and the development of osteoarthritis (OA). This systematic review investigated the association between sports activity, sports type, and the risk of developing OA.

METHODS

A systematic review was performed by assessing studies that have investigated the risk of OA development in sports. Data extracted included general information, study design, number of participants, related body mass index, sports type, and assessment of OA. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 63 studies were included in this systematic review. The overall Newcastle-Ottawa Scale score was 6.46±1.44 demonstrating a good methodological quality of the articles included in the present study. A total of 628,036 participants were included, with a mean follow-up of 8.0±8.4 years. The mean age of the included athletes was 45.6±15.8, with a mean body mass index of 24.9±2.3 kg/m 2 .

CONCLUSION

Football and soccer players seem to be at higher risk for the development of OA, although the injury status of the joint should be considered when assessing the risk of OA. High equipment weight and increased injury risk also put military personnel at a higher risk of OA, although elite dancing leads to more hip labral tears. Femoroacetabular impingement was also often diagnosed in ice-hockey players and ballet dancers.

The Influence of Athletes' Age in the Onset of Osteoarthritis: A Systematic Review

PURPOSE

Whether sport participation is a risk factor for osteoarthritis (OA) development or progression is controversial. Mechanical overload, injuries, genetics, and acquired disorders concur to the onset of OA, with high variability between sports and participants. This study investigated the association between participation in specific sports and the risk of developing knee and hip OA in athletes at different ages. We hypothesized that young athletes who are exposed to high levels of physical activities have a greater risk of developing OA.

MATERIALS AND METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Google scholar, EMABSE, and Web of Science were accessed in October 2021. No time constrains were used for the search. All the published clinical studies reporting data about relationship between physical activity, OA, and age were included.

RESULTS

The Newcastle-Ottawa Scale resulted in a final score ≥7 for all studies, attesting good quality of the methodological assessment. Data from 27,364 patients were retrieved. The mean age was 48.2±16.7 years. In all, 21.8% were women.

CONCLUSIONS

Our systematic review suggests an association between high levels of physical activities and knee and hip OA in men younger than 50 years. People who practice intense physical activity, such as professional athletes or heavy workers, are more prone to develop early-onset 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.

The Influence of Running on Lower Limb Cartilage: A Systematic Review and Meta-analysis

BACKGROUND

Running is a popular activity practiced worldwide. It is important to understand how running affects joint health to provide recommendations to sports medicine practitioners and runners.

OBJECTIVE

Our aim was to summarize the influence of running on lower limb cartilage morphology and composition using quantitative magnetic resonance imaging (MRI).

METHODS

Prospective repeated-measures studies evaluating cartilage using MRI before and after running were included. Data sources included Pubmed, Embase, CINAHL, SportDiscus, Web of Science, and Cochrane Central Registry of Controlled Trials. Qualitative analyses considered the number and methodological quality ratings of studies based on the QualSyst tool, and recommendations were based on the strength of evidence (strong, moderate, limited, or very limited). Quantitative analysis involved meta-analyses, for which effect sizes were calculated as Hedge's g standardized mean differences.

RESULTS

We included 43 articles, assessing seven outcomes (lesions, volume, thickness, glycosaminoglycan content, and T1ρ, T2, and T2* relaxation times). Nineteen articles were rated as high quality, 24 were rated as moderate quality, and none were rated as low quality. Qualitative analyses suggest that running may cause an immediate reduction in knee cartilage volume, thickness, as well as T1ρ and T2 relaxation times immediately; however, these changes did not persist. Meta-analyses revealed a small and moderate decrease immediately following a single running bout in T2 relaxation time in the medial femur and tibia, respectively. Qualitative analyses indicated that the influence of repeated exposure to running on cartilage morphology and composition was limited. Despite conflicting evidence regarding pre-existing knee cartilage lesions, moderate evidence suggests that running does not lead to the formation of new lesions. Repeated running exposure did not cause changes to foot and ankle cartilage thickness or composition.

CONCLUSIONS

Changes to lower limb cartilage following running are transient. Immediate changes to cartilage morphology and composition, which likely reflect natural fluid dynamics, do not persist and were generally not significant when pooled statistically. Results suggest that cartilage recovers well from a single running bout and adapts to repeated exposure. Given that moderate evidence indicates that running does not lead to new lesions, future trials should focus on clinical populations, such as those with osteoarthritis.

TRIAL REGISTRATION

Not applicable.

Impact of different physical activity types on knee joint structural degeneration assessed with 3-T MRI in overweight and obese subjects: data from the osteoarthritis initiative

OBJECTIVE

To assess the impact of different types of physical activity types on longitudinal knee joint structural changes over 48 months in overweight and obese subjects.

MATERIALS AND METHODS

We included 415 subjects with a BMI ≥ 25 kg/m², Kellgren-Lawrence scores ≤ 3 at baseline and Whole-Organ Magnetic Resonance Imaging Score (WORMS) scores available from the Osteoarthritis Initiative cohort. Regular self-reported participation in six physical activity types was assessed: ball sports, bicycling, jogging/running, elliptical-trainer, racquet sports, and swimming. Moreover, they were classified into high- and low-impact physical activity groups. Evaluation of structural knee abnormalities was performed using WORMS obtained by two independent observers blinded to the subjects' physical activity and time point. Linear regression models were used to assess the associations between participation in different physical activity types and changes in WORMS.

RESULTS

No significant differences in epidemiological data were found between the groups except for gender composition, and there were no significant differences in baseline WORMS. In the cohort as a whole and most exercise groups overall WORMS significantly increased during the observational period. Highest increases compared to the remainder of the group were found in the high impact group (increase in WORMS 4.65; [95% CI] [3.94,5.35]; p = 0.040) and the racquet sports group (6.39; [95% CI] [5.13,7.60]; p ≤ 0.001). Subjects using an elliptical-trainer showed the lowest increase in WORMS (- 1.50 [- 0.21, 3.22]; p = 0.002).

CONCLUSION

Progression of knee joint degeneration was consistently higher in subjects engaging in high-impact and racquet sports while subjects using an elliptical-trainer showed the smallest changes in structural degeneration. This work was presented during the 2020 Radiological Society of North America Annual meeting.

Clinical application of foot strike run retraining for military service members with chronic knee pain

INTRODUCTION

Military training is associated with a high incidence of knee pain. Conversion from a rearfoot to non-rearfoot strike during running is effective at reducing knee pain in research environments. The purpose of this report was to demonstrate run retraining as a clinical intervention for service members with knee pain.

METHODS

Sixteen service members with running-related chronic knee pain underwent run retraining that converted foot strike from a rearfoot to a non-rearfoot strike using real-time visual feedback. The Lower Extremity Functional Scale (LEFS) and Numerical Pain Rating Scale (NPRS) for knee pain during running were assessed pretraining, at the final training session and at a 1-month follow-up. During running, foot inclination angle and vertical ground reaction force (VGRF) average loading rate were measured pretraining and at 1 month of follow-up.

RESULTS

Service members underwent 7.4±1.0 training sessions over the course of 15.8±4.6 days. LEFS improved by 8±6 points immediately after retraining, with an overall improvement of 10±6 points from pretraining to 1-month follow-up (p<0.01). NPRS improved by 2.0±0.4 points immediately after retraining, with an overall improvement of 2.0±0.4 points from pretraining to 1-month follow-up (p<0.01). Conversion to a non-rearfoot strike pattern was apparent at follow-up for all but two patients. VGRF average loading rate decreased by 56%±17% (p<0.01) from pretraining to 1-month follow-up.

CONCLUSIONS

Knee pain and function improved as a result of non-rearfoot strike run retraining, which supports the clinical use of this evidence-based intervention.

Self-Report and Contemporaneously Recorded Running Agreement in Recreational Athletes

Leech RD, Grunseit A, and Edwards KL. Self-report and contemporaneously recorded running agreement in recreational athletes. J Strength Cond Res XX(X): 000-000, 2020-Accurate assessment of running exposure in research or clinical practice relies on the ability to measure the behavior validly and reliably. Self-reported physical activity (PA) (including running), although commonly used, is subject to bias. User-owned wearable technological devices provide a potential contemporaneously collected data source for validating retrospective running-specific questionnaires. This study assesses agreement between self-reported running and contemporaneously collected running data. Self-reported running and corresponding contemporaneously recorded for current (at the time of questionnaire completion) and historical (6 months prior) was collected. Concordance Correlations and Bland-Altman Limits of Agreement measured extent of agreement. Categories for Metabolic Equivalent Task (MET) hours per week were calculated from total running distance. Unweighted and weighted Kappas were used to compare classification of levels of running by the 2 data sources. Running data were collected from 139 subjects (mean age 51.1 years). Self-report data were higher than contemporaneous data. Average estimated pace from both sources were similar, with high variance in some individuals. Differences of 43.5-57.1% were reported for current mean weekly running distances for 7-day, 4-week, and 12-week running periods. The level of agreement in classification between self-report and contemporaneous running data MET/HR categories was fair (unweighted K = 0.24-0.33) to moderate (weighted K = 0.46-0.63). Compared with contemporaneous running data, runners over-estimate the frequency, distance, and duration of running in self-report. Runners tend to discount nonrunning periods and unusual runs when estimating current and historical "average" running. The opportunities and limitations of different contemporaneous running data collection methods as a PA comparator must be acknowledged.

Understanding Atherosclerosis Through an Osteoarthritis Data Set

Atherosclerotic cardiovascular disease remains a worldwide epidemic and one of the leading causes of death nowadays. Vessel wall imaging can be used to understand the development and progression of atherosclerosis, but it is rarely done because of the high cost. We recently identified the Osteoarthritis Initiative, a large prospective cohort study of knee osteoarthritis, which might serve as a valuable source for atherosclerosis research with its serial knee magnetic resonance imaging data. We have found that these images are suitable for vessel wall image analysis of the lower extremity arteries. Here, we will introduce the Osteoarthritis Initiative data set and explain why it could be used for cardiovascular research purposes. Also, we will briefly comment on peripheral artery atherosclerosis as it is covered in the Osteoarthritis Initiative image data set and review the use of vessel wall imaging for studying atherosclerosis. We think data mining of imaging studies, not originally designed on cardiovascular research, can not only maximize the value of the imaging data set but also boost our understanding of atherosclerosis.

Knee osteoarthritis risk in non-industrial societies undergoing an energy balance transition: evidence from the indigenous Tarahumara of Mexico

Non-industrial societies with low energy balance levels are expected to be less vulnerable than industrial societies to diseases associated with obesity including knee osteoarthritis. However, as non-industrial societies undergo rapid lifestyle changes that promote positive energy balance, individuals whose metabolisms are adapted to energetic scarcity are encountering greater energy abundance, increasing their propensity to accumulate abdominal adipose tissue and thus potentially their sensitivity to obesity-related diseases.

OBJECTIVES

Here, we propose that knee osteoarthritis is one such disease for which susceptibility is amplified by this energy balance transition.

METHODS

Support for our hypothesis comes from comparisons of knee radiographs, knee pain and anthropometry among men aged ≥40 years in two populations: Tarahumara subsistence farmers in Mexico undergoing the energy balance transition and urban Americans from Framingham, Massachusetts.

RESULTS

We show that despite having markedly lower obesity levels than the Americans, the Tarahumara appear predisposed to accrue greater abdominal adiposity (ie, larger abdomens) for a given body weight, and are more vulnerable to radiographic and symptomatic knee osteoarthritis at lower levels of body mass index. Also, proportionate increases in abdomen size in the two groups are associated with greater increases in radiographic knee osteoarthritis risk among the Tarahumara than the Americans, implying that the abdominal adipose tissue of the Tarahumara is a more potent stimulus for knee degeneration.

CONCLUSIONS

Heightened vulnerability to knee osteoarthritis among non-industrial societies experiencing rapid lifestyle changes is a concern that warrants further investigation since such groups represent a large but understudied fraction of the global population.

Evidence that Swimming May Be Protective of Knee Osteoarthritis: Data from the Osteoarthritis Initiative

BACKGROUND

To date, there have not been any epidemiologic studies that have evaluated the association between swimming over a lifetime and knee health.

OBJECTIVE

The study aimed to evaluate the relationship of a history of swimming with knee pain, radiographic knee OA (ROA), and symptomatic knee OA (SOA).

DESIGN

Cross-sectional retrospective study.

SETTING

Four academic centers in the United States.

PARTICIPANTS

Respondents to the historical physical activity survey within the Osteoarthritis Initiative with knee radiographs and symptom assessments.

METHODS

In this retrospective study nested within the Osteoarthritis Initiative, researchers performed logistic regression with the predictor being swimming over a lifetime and over particular age ranges.

MAIN OUTCOME MEASUREMENTS

Person-based definitions of frequent knee pain, ROA, and SOA.

RESULTS

A total of 2637 participants were included, with a mean age of 64.3 years (SD 8.9), body mass index of 28.4 kg/m² (SD 4.9), and 44.2% male. Over a lifetime, the adjusted prevalence measures for frequent knee pain, ROA, and SOA for any versus no history of swimming were 36.4% (33.4% - 39.5%) v. 39.9% (37.4% - 42.5%), 54.3% (51.0% - 57.6%) v. 61.1% (58.4% - 63.7%), and 21.9% (19.4% - 24.7%) v. 27.0% (24.7% - 29.4%) respectively.

CONCLUSIONS

This is the first epidemiologic study to indicate that swimming is potentially beneficial toward knee health, particularly when performed earlier in life (before age 35). Future prospective studies are needed to confirm these findings and to better scrutinize the associations in older age groups.

The different influence of high levels of physical activity on the incidence of knee OA in overweight and obese men and women-a gender specific analysis

OBJECTIVE

To investigate the influence of physical activity on incidence of knee osteoarthritis (OA) in overweight and obese men and women.

DESIGN

Data were extracted from the Osteoarthritis Initiative cohort on 1,667 participants without symptomatic knee OA at baseline. We used logistic regression and marginal effect models to estimate the effect of body mass index (BMI) and reported physical activity score, together with the interaction between them, on the development of radiographic knee OA, symptomatic knee OA and joint space narrowing (JSN) after 96-months.

RESULTS

Men in the most active quartile had almost double the likelihood of knee OA, independent of OA definition [e.g., odds ratio (OR) 2.4 (95%CI: 1.2-4.5) for radiographic knee OA]. Interaction analyses showed statistically significant interactions between physical activity and BMI on developing knee OA (i) radiographic OA _interaction(P = 0.039), (ii) symptomatic OA _interaction(P = 0.022), (iii) JSN _interactionP = 0.012). The margin plots in men also demonstrated that the effect of physical activity on different measures of knee OA were modified by high levels of BMI. These effects were not mirrored in women where at all BMI levels, the level of reported physical activity did not influence likelihood of knee OA independent of OA definition.

CONCLUSIONS

In overweight and obese men, there appears to be a threshold above which increasing levels of physical activity are associated with higher risk of knee OA. This is absent in women.

Running Dose and Risk of Developing Lower-Extremity Osteoarthritis

Whether or not running leads to the development of knee and hip osteoarthritis has been a much-debated topic and is often a question patients pose to their physicians. Recent literature adds to a growing body of evidence suggesting that lower-dose running may be protective against the development of osteoarthritis, whereas higher-dose running may increase one's risk of developing lower-extremity osteoarthritis. However, running dose remains challenging to define, leading to difficulty in providing firm recommendations to patients regarding the degree of running which may be safe. Furthermore, when counseling patients regarding their risk of developing lower-extremity osteoarthritis secondary to running, clinicians must consider many additional factors, such as the numerous health benefits from running and individual risk factors for developing osteoarthritis.

Classification of higher- and lower-mileage runners based on running kinematics

BACKGROUND

Running-related overuse injuries can result from the combination of extrinsic (e.g., running mileage) and intrinsic risk factors (e.g., biomechanics and gender), but the relationship between these factors is not fully understood. Therefore, the first purpose of this study was to determine whether we could classify higher- and lower-mileage runners according to differences in lower extremity kinematics during the stance and swing phases of running gait. The second purpose was to subgroup the runners by gender and determine whether we could classify higher- and lower-mileage runners in male and female subgroups.

METHODS

Participants were allocated to the "higher-mileage" group (≥32 km/week; n = 41 (30 females)) or to the "lower-mileage" group (≤25 km; n = 40 (29 females)). Three-dimensional kinematic data were collected during 60 s of treadmill running at a self-selected speed (2.61 ± 0.23 m/s). A support vector machine classifier identified kinematic differences between higher- and lower-mileage groups based on principal component scores.

RESULTS

Higher- and lower-mileage runners (both genders) could be separated with 92.59% classification accuracy. When subgrouping by gender, higher- and lower-mileage female runners could be separated with 89.83% classification accuracy, and higher- and lower-mileage male runners could be separated with 100% classification accuracy.

CONCLUSION

These results demonstrate there are distinct kinematic differences between subgroups related to both mileage and gender, and that these factors need to be considered in future research.

Objectively Measured Physical Activity and Risk of Knee Osteoarthritis

PURPOSE

This study aimed to examine the association between objectively measured physical activity and risk of developing incident knee osteoarthritis (OA) in a community-based cohort of middle-age and older adults.

METHODS

We used data from the Osteoarthritis Initiative, an ongoing prospective cohort study of adults 45 to 83 yr of age at initial enrollment with elevated risk of symptomatic knee OA. Moderate-vigorous physical activity (MVPA) was measured by a uniaxial accelerometer for seven continuous days in two data collection cycles and was categorized as inactive (<10 min·wk), low activity (10-<150 min·wk), and active (≥150 min·wk). Incident knee OA based on radiographic and symptomatic OA and joint space narrowing were analyzed as outcomes over 4 yr of follow-up. Participants free of the outcome of interest in both knees at study baseline were included (sample sizes ranged from 694 to 1331 for different outcomes). We estimated hazard ratio (HR) with 95% confidence intervals (CI).

RESULTS

In multivariate analyses, active MVPA participation was not significantly associated with risk of incident radiographic knee OA (HR = 1.52, 95% CI = 0.68-3.40), symptomatic knee OA (HR = 1.17, 95% CI = 0.44-3.09), or joint space narrowing (HR = 0.87, 95% CI = 0.37-2.06) when compared with inactive MVPA participation. Similar results were found for participants with low activity MVPA.

CONCLUSION

MVPA was not associated with the risk of developing incident knee OA or joint space narrowing over 4 yr of follow-up among Osteoarthritis Initiative participants who are at increased risk of knee OA.

What are the perceptions about running and knee joint health among the public and healthcare practitioners in Canada?

Objectives

To evaluate the perceptions of the general public and healthcare practitioners (HCP) in Canada about the relationship between running and knee joint health, and to explore HCP`s usual recommendations to runners with knee osteoarthritis (KOA).

Methods

Non-runners and runners (with and without KOA) and HCP completed an online survey regarding the safety of running for knee joint health. HCP also provided information related to usual clinical recommendations. Proportions of agreement were compared between non-runners and runners.

Results

A total of 114 non-runners, 388 runners and 329 HCP completed the survey. Overall, running was perceived as detrimental for the knee joint by 13.1% of the general public, while 25.9% were uncertain. More uncertainty was reported regarding frequent (33.9%) and long-distance (43.6%) running. Statistical analyses revealed greater proportions of non-runners perceiving running negatively compared with runners. Overall, 48.4% believed that running in the presence of KOA would lead to disease progression, while 53.1% believed running would lead to premature arthroplasty. In HCP, 8.2%, 9.1% and 22.2% perceived that running in general, running frequently, or running long-distances are risk factors for KOA, respectively. 37.1% and 2.7% of HCP typically recommended patients with KOA to modify their running training or to quit running, respectively.

Conclusion

High rates of uncertainty among the general public and HCP in Canada outline the need for further studies about running and knee joint health. Filling knowledge gaps will help inform knowledge translation strategies to better orientate the general public and HCP about the safety of running for knee joint health.

Running does not increase symptoms or structural progression in people with knee osteoarthritis: data from the osteoarthritis initiative

Higher levels of moderate to vigorous physical activity improve all-cause mortality and cardiovascular events. However, the effect of running, a moderate to vigorous activity, in those with knee osteoarthritis (OA), a common arthritis that occurs with aging, a high-risk group for mortality and cardiovascular events, is unclear. Therefore, we aimed to evaluate the association of self-selected running on OA symptom and structure progression in people with knee OA. This nested cohort study within the Osteoarthritis Initiative (OAI) (2004-2014) included those at least 50 years old with OA in at least one knee. Runners were defined using a self-administered questionnaire at the 96-month visit. At baseline and 48-months, symptoms were assessed and radiographs were scored for Kellgren-Lawrence (KL) grade (2-4) and medial Joint Space Narrowing (JSN) score (0-3). We evaluated the association of self-selected running with outcomes: KL worsening, medial JSN worsening, new knee pain, and improved knee pain over 48 months, adjusting for baseline age, sex, body mass index (BMI), KL score, contralateral KL score, contralateral knee pain, and injury. If data were not available at the 48-month visit, then they were imputed from the 36-month visit. One thousand two hundred three participants had a mean age of 63.2 (7.9) years, BMI of 29.5 (4.6) kg/m², 45.3% male, and 11.5% runners. Data from 8% of participants required imputation. Adjusted odds ratios for KL grade worsening and new frequent knee pain were 0.9 (0.6-1.3) and 0.9 (0.6-1.6) respectively. Adjusted odds ratio for frequent knee pain resolution was 1.7 (1.0-2.8). Among individuals 50 years old and older with knee OA, self-selected running is associated with improved knee pain and not with worsening knee pain or radiographically defined structural progression. Therefore, self-selected running, which is likely influenced by knee symptoms and may result in lower intensity and shorter duration sessions of exercise, need not be discouraged in people with knee OA.

Epidemiology of osteoarthritis: literature update

PURPOSE OF REVIEW

The purpose of this review is to highlight recent studies of osteoarthritis epidemiology, including research on prevalence, disease impact, and potential risk factors.

RECENT FINDINGS

Osteoarthritis is highly prevalent in the United States and around the globe. It is a leading cause of disability and can negatively impact people's physical and mental well being. Healthcare resources and costs associated with managing the disease can be substantial. There is increasing evidence that there are different osteoarthritis phenotypes that reflect different mechanisms of the disease. Various person-level risk factors are recognized, including sociodemographic characteristics (e.g. female sex, African-American race), genetic predispositions, obesity, diet-related factors, and high bone density/mass. Joint-level risk factors include specific bone/joint shapes, thigh flexor muscle weakness, joint malalignment, participation in certain occupational/sports activities, and joint injury. Recent studies have enhanced our understanding of preradiographic lesions associated with osteoarthritis.

SUMMARY

Application of these new findings may allow us to develop innovative strategies and novel therapies with the purpose of preventing new disease onset and minimizing disease progression.

The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis

Study Design Systematic review and meta-analysis. Background Running is a healthy and popular activity worldwide, but data regarding its association with osteoarthritis (OA) are conflicting. Objectives To evaluate the association of hip and knee OA with running and to explore the influence of running intensity on this association. Methods PubMed, Embase, and Cochrane Library databases were used to identify studies investigating the occurrence of OA of the hip and/or knee among runners. A meta-analysis of studies comparing this occurrence between runners and controls (sedentary, nonrunning individuals) was conducted. Runners were regarded as "competitive" if they were reported as professional/elite athletes or participated in international competitions. Recreational runners were individuals running in a nonprofessional (amateur) context. The prevalence rate and odds ratio (with 95% confidence interval [CI]) for OA between runners (at competitive and recreational levels) and controls were calculated. Subgroup analyses were conducted for OA location (hip or knee), sex, and years of exposure to running (less or more than 15 years). Results Twenty-five studies (n = 125810 individuals) were included and 17 (n = 114829 individuals) were meta-analyzed. The overall prevalence of hip and knee OA was 13.3% (95% CI: 11.6%, 15.2%) in competitive runners, 3.5% (95% CI: 3.4%, 3.6%) in recreational runners, and 10.2% (95% CI: 9.9%, 10.6%) in controls. The odds ratio for hip and/or knee OA in competitive runners was higher than that in recreational runners (1.34; 95% CI: 0.97, 1.86 and 0.86; 95% CI: 0.69, 1.07, respectively; controls as reference group; for difference, P<.001). Exposure to running of less than 15 years was associated with a lower association with hip and/or knee OA compared with controls (OR = 0.6; 95% CI: 0.49, 0.73). Conclusion Recreational runners had a lower occurrence of OA compared with competitive runners and controls. These results indicated that a more sedentary lifestyle or long exposure to high-volume and/or high-intensity running are both associated with hip and/or knee OA. However, it was not possible to determine whether these associations were causative or confounded by other risk factors, such as previous injury. Level of Evidence Etiology/harm, level 2a. J Orthop Sports Phys Ther 2017;47(6):373-390. doi:10.2519/jospt.2017.7137.

Impact of Physical Activity in Cardiovascular and Musculoskeletal Health: Can Motion Be Medicine?

Physical activity is a well-known therapeutic tool for various types of medical conditions, including vasculopathic diseases such as coronary artery disease, stroke, type 2 diabetes, and obesity. Additionally, increased physical activity has been proposed as a therapy to improve musculoskeletal health; however, there are conflicting reports about physical activity potentially leading to degenerative musculoskeletal disease, especially osteoarthritis (OA). Additionally, although physical activity is known to have its benefits, it is unclear as to what amount of physical activity is the most advantageous. Too much, as well as not enough exercise can have negative consequences. This could impact how physicians advise their patients about exercise intensity. Multiple studies have evaluated the effect of physical activity on various aspects of health. However, there is a paucity of systematic studies which review cardiovascular and musculoskeletal health as outcomes. Therefore, the purpose of this review was to assess how physical activity impacts these aspects of health. Specifically, we evaluated the effect of various levels of physical activity on: 1) cardiovascular and 2) musculoskeletal health. The review revealed that physical activity may decrease cardiovascular disease and improve OA symptoms, and therefore, motion can be considered a “medicine”. However, because heavy activity can potentially lead to increased OA risk, physicians should advise their patients that excessive activity can also potentially impact their health negatively, and should be done in moderation, until further study.