Background:
The National Center for Injury Prevention and Control, noting flaws in previous running injury research, called for more rigorous prospective designs and comprehensive analyses to define ...the origin of running injuries.
Purpose:
To determine the risk factors that differentiate recreational runners who remain uninjured from those diagnosed with an overuse running injury during a 2-year observational period.
Study Design:
Cohort study; Level of evidence, 2.
Methods:
Inclusion criteria were running a minimum of 5 miles per week and being injury free for at least the past 6 months. Data were collected at baseline on training, medical and injury histories, demographics, anthropometrics, strength, gait biomechanics, and psychosocial variables. Injuries occurring over the 2-year observation period were diagnosed by an orthopaedic surgeon on the basis of predetermined definitions.
Results:
Of the 300 runners who entered the study, 199 (66%) sustained at least 1 injury, including 73% of women and 62% of men. Of the injured runners, 111 (56%) sustained injuries more than once. In bivariate analyses, significant (P ≤ .05) factors at baseline that predicted injury were as follows: Short Form Health Survey–12 mental component score (lower mental health–related quality of life), Positive and Negative Affect Scale negative affect score (more negative emotions), sex (higher percentage of women were injured), and knee stiffness (greater stiffness was associated with injury); subsequently, knee stiffness was the lone significant predictor of injury (odds ratio = 1.18) in a multivariable analysis. Flexibility, quadriceps angle, arch height, rearfoot motion, strength, footwear, and previous injury were not significant risk factors for injury.
Conclusion:
The results of this study indicate the following: (1) among recreational runners, women sustain injuries at a higher rate than men; (2) greater knee stiffness, more common in runners with higher body weights (≥80 kg), significantly increases the odds of sustaining an overuse running injury; and (3) contrary to several long-held beliefs, flexibility, arch height, quadriceps angle, rearfoot motion, lower extremity strength, weekly mileage, footwear, and previous injury are not significant etiologic factors across all overuse running injuries.
In their comments about our recent article,1 Dr Fan and colleagues question the use of a completers-only vs an intention-to-treat analysis. A strict definition of the intention-to-treat principle in ...clinical trials states that all randomized participants are included in the statistical analyses and analyzed according to the treatment group to which they were randomly assigned, irrespective of their treatment and adherence to the protocol. Because some participants did not attend the follow-up visits (6, 12, or 18 months postrandomization), our analyses could not be defined as intention to treat. All other components of the intention-to-treat definition were upheld, and participants with incomplete follow-up data (ie, missing at only 1 or 2 follow-up visits) were considered completers and their outcomes were included in the primary analysis. Furthermore, a prespecified sensitivity analysis using multiple imputation for all randomized participants was included in the article's supplemental information and resulted in similar between-group differences in WOMAC pain scores. Both were statistically significant, and the differences between groups were of uncertain clinical importance. Our approach aligns with guidance published elsewhere.
Objective
We examined the dose‐response relationship between weight reduction and pain/functional improvement in persons with symptomatic knee osteoarthritis (KOA) participating in a community‐based ...weight loss program.
Methods
Consecutive participants with KOA and enrolled in the 18‐week Osteoarthritis Healthy Weight for Life weight‐loss program were selected. In this completer‐type analysis, participants were assessed at baseline, 6 weeks, and 18 weeks for body weight and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. The dose‐response relationship between weight‐change categories (>10%, 7.6–10%, 5.1–7.5%, 2.6–5.0%, and <2.5% of body weight loss) and change in KOOS scores was assessed by repeated‐measures analysis of variance, controlling for sex and age, body mass index (BMI), and KOOS. The Western Ontario McMaster Universities Osteoarthritis Index function score derived from the KOOS was used to assess a meaningful clinical functional improvement.
Results
A total of 1,383 persons (71% females) were enrolled. Mean ± SD age, height, and weight were 64 ± 8.7 years, 1.66 ± 0.09 meters, and 95.1 ± 17.2 kg, respectively. Mean ± SD BMI was 34.4 ± 5.2 kg/m2 with 82% of participants obese at baseline. A total of 1,304 persons (94%) achieved a >2.5% reduction in body weight. There was a significant dose‐response relationship between all KOOS subscales and percentage of weight change across all weight‐change categories. Participants required ≥7.7% (95% confidence interval 5.2, 13.3) body weight loss to achieve a minimal clinically important improvement in function.
Conclusion
There is a significant dose‐response relationship between percentage of weight loss and symptomatic improvement. This study confirms the feasibility of weight loss as a therapeutic intervention in KOA in a community‐based setting.
Objective
The prevalence of symptomatic knee osteoarthritis (OA) has been increasing over the past several decades in the US, concurrent with an aging population and the growing obesity epidemic. We ...quantify the impact of these factors on the number of persons with symptomatic knee OA in the early decades of the 21st century.
Methods
We calculated the prevalence of clinically diagnosed symptomatic knee OA from the National Health Interview Survey 2007–2008 and derived the proportion with advanced disease (defined as Kellgren/Lawrence grade 3 or 4) using the Osteoarthritis Policy Model, a validated simulation model of knee OA. Incorporating contemporary obesity rates and population estimates, we calculated the number of persons living with symptomatic knee OA.
Results
We estimate that approximately 14 million persons had symptomatic knee OA, with advanced OA comprising more than half of those cases. This includes more than 3 million persons of racial/ethnic minorities (African American, Hispanic, and other). Adults younger than 45 years of age represented nearly 2 million cases of symptomatic knee OA and individuals between 45 and 65 years of age comprised 6 million more cases.
Conclusion
More than half of all persons with symptomatic knee OA are younger than 65 years of age. As many of these younger persons will live for 3 decades or more, there is substantially more time for greater disability to occur, and policymakers should anticipate health care utilization for knee OA to increase in the upcoming decades. These data emphasize the need for the deployment of innovative prevention and treatment strategies for knee OA, especially among younger persons.
Clinical trials conventionally test aggregate mean differences and assume homogeneous variances across treatment groups. However, significant response heterogeneity may exist. The purpose of this ...study was to model treatment response variability using gait speed change among older adults participating in caloric restriction (CR) trials. Eight randomized controlled trials (RCTs) with five- or six-month assessments were pooled, including 749 participants randomized to CR and 594 participants randomized to non-CR (NoCR). Statistical models compared means and variances by CR assignment and exercise assignment or select subgroups, testing for treatment differences and interactions for mean changes and standard deviations. Continuous equivalents of dichotomized variables were also fit. Models used a Bayesian framework, and posterior estimates were presented as means and 95% Bayesian credible intervals (BCI). At baseline, participants were 67.7 (SD = 5.4) years, 69.8% female, and 79.2% white, with a BMI of 33.9 (4.4) kg/m2. CR participants reduced body mass CR: -7.7 (5.8) kg vs. NoCR: -0.9 (3.5) kg and increased gait speed CR: +0.10 (0.16) m/s vs. NoCR: +0.07 (0.15) m/s more than NoCR participants. There were no treatment differences in gait speed change standard deviations CR-NoCR: -0.002 m/s (95% BCI: -0.013, 0.009). Significant mean interactions between CR and exercise assignment 0.037 m/s (95% BCI: 0.004, 0.070), BMI 0.034 m/s (95% BCI: 0.003, 0.066), and IL-6 0.041 m/s (95% BCI: 0.009, 0.073) were observed, while variance interactions were observed between CR and exercise assignment -0.458 m/s (95% BCI: -0.783, -0.138), age -0.557 m/s (95% BCI: -0.900, -0.221), and gait speed -0.530 m/s (95% BCI: -1.018, -0.062) subgroups. Caloric restriction plus exercise yielded the greatest gait speed benefit among older adults with obesity. High BMI and IL-6 subgroups also improved gait speed in response to CR. Results provide a novel statistical framework for identifying treatment heterogeneity in RCTs.
IMPORTANCE Knee osteoarthritis (OA), a common cause of chronic pain and disability, has biomechanical and inflammatory origins and is exacerbated by obesity. OBJECTIVE To determine whether a ≥10% ...reduction in body weight induced by diet, with or without exercise, would improve mechanistic and clinical outcomes more than exercise alone. DESIGN, SETTING, AND PARTICIPANTS Single-blind, 18-month, randomized clinical trial at Wake Forest University between July 2006 and April 2011. The diet and exercise interventions were center-based with options for the exercise groups to transition to a home-based program. Participants were 454 overweight and obese older community-dwelling adults (age ≥55 years with body mass index of 27-41) with pain and radiographic knee OA. INTERVENTIONS Intensive diet-induced weight loss plus exercise, intensive diet-induced weight loss, or exercise. MAIN OUTCOMES AND MEASURES Mechanistic primary outcomes: knee joint compressive force and plasma IL-6 levels; secondary clinical outcomes: self-reported pain (range, 0-20), function (range, 0-68), mobility, and health-related quality of life (range, 0-100). RESULTS Three hundred ninety-nine participants (88%) completed the study. Mean weight loss for diet + exercise participants was 10.6 kg (11.4%); for the diet group, 8.9 kg (9.5%); and for the exercise group, 1.8 kg (2.0%). After 18 months, knee compressive forces were lower in diet participants (mean, 2487 N; 95% CI, 2393 to 2581) compared with exercise participants (2687 N; 95% CI, 2590 to 2784, pairwise difference Δexercise vs diet = 200 N; 95% CI, 55 to 345; P = .007). Concentrations of IL-6 were lower in diet + exercise (2.7 pg/mL; 95% CI, 2.5 to 3.0) and diet participants (2.7 pg/mL; 95% CI, 2.4 to 3.0) compared with exercise participants (3.1 pg/mL; 95% CI, 2.9 to 3.4; Δexercise vs diet + exercise = 0.39 pg/mL; 95% CI, −0.03 to 0.81; P = .007; Δexercise vs diet = 0.43 pg/mL; 95% CI, 0.01 to 0.85, P = .006). The diet + exercise group had less pain (3.6; 95% CI, 3.2 to 4.1) and better function (14.1; 95% CI, 12.6 to 15.6) than both the diet group (4.8; 95% CI, 4.3 to 5.2) and exercise group (4.7; 95% CI, 4.2 to 5.1, Δexercise vs diet + exercise = 1.02; 95% CI, 0.33 to 1.71; Ppain = .004; 18.4; 95% CI, 16.9 to 19.9; Δexercise vs diet + exercise, 4.29; 95% CI, 2.07 to 6.50; Pfunction < .001). The diet + exercise group (44.7; 95% CI, 43.4 to 46.0) also had better physical health-related quality of life scores than the exercise group (41.9; 95% CI, 40.5 to 43.2; Δexercise vs diet + exercise = −2.81; 95% CI, −4.76 to −0.86; P = .005). CONCLUSIONS AND RELEVANCE Among overweight and obese adults with knee OA, after 18 months, participants in the diet + exercise and diet groups had more weight loss and greater reductions in IL-6 levels than those in the exercise group; those in the diet group had greater reductions in knee compressive force than those in the exercise group. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00381290
IMPORTANCE: Thigh muscle weakness is associated with knee discomfort and osteoarthritis disease progression. Little is known about the efficacy of high-intensity strength training in patients with ...knee osteoarthritis or whether it may worsen knee symptoms. OBJECTIVE: To determine whether high-intensity strength training reduces knee pain and knee joint compressive forces more than low-intensity strength training and more than attention control in patients with knee osteoarthritis. DESIGN, SETTING, AND PARTICIPANTS: Assessor-blinded randomized clinical trial conducted at a university research center in North Carolina that included 377 community-dwelling adults (≥50 years) with body mass index (BMI) ranging from 20 to 45 and with knee pain and radiographic knee osteoarthritis. Enrollment occurred between July 2012 and February 2016, and follow-up was completed September 2017. INTERVENTIONS: Participants were randomized to high-intensity strength training (n = 127), low-intensity strength training (n = 126), or attention control (n = 124). MAIN OUTCOMES AND MEASURES: Primary outcomes at the 18-month follow-up were Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) knee pain (0 best-20 worst; minimally clinically important difference MCID, 2) and knee joint compressive force, defined as the maximal tibiofemoral contact force exerted along the long axis of the tibia during walking (MCID, unknown). RESULTS: Among 377 randomized participants (mean age, 65 years; 151 women 40%), 320 (85%) completed the trial. Mean adjusted (sex, baseline BMI, baseline outcome values) WOMAC pain scores at the 18-month follow-up were not statistically significantly different between the high-intensity group and the control group (5.1 vs 4.9; adjusted difference, 0.2; 95% CI, −0.6 to 1.1; P = .61) or between the high-intensity and low-intensity groups (5.1 vs 4.4; adjusted difference, 0.7; 95% CI, −0.1 to 1.6; P = .08). Mean knee joint compressive forces were not statistically significantly different between the high-intensity group and the control group (2453 N vs 2512 N; adjusted difference, −58; 95% CI, −282 to 165 N; P = .61), or between the high-intensity and low-intensity groups (2453 N vs 2475 N; adjusted difference, −21; 95% CI, −235 to 193 N; P = .85). There were 87 nonserious adverse events (high-intensity, 53; low-intensity, 30; control, 4) and 13 serious adverse events unrelated to the study (high-intensity, 5; low-intensity, 3; control, 5). CONCLUSIONS AND RELEVANCE: Among patients with knee osteoarthritis, high-intensity strength training compared with low-intensity strength training or an attention control did not significantly reduce knee pain or knee joint compressive forces at 18 months. The findings do not support the use of high-intensity strength training over low-intensity strength training or an attention control in adults with knee osteoarthritis. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01489462
Honoring Walt Ettinger, Jr Applegate, William B; Colenda, Christopher C; Messier, Stephen P ...
Journal of the American Geriatrics Society (JAGS),
2024-Apr-29, 2024-04-29, 20240429
Journal Article
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