The association between joint stress from physical activity and self-reported osteoarthritis: an analysis of the Cooper Clinic data

The association between basal metabolic rate and osteoarthritis: a Mendelian randomization study

BACKGROUND

The role of the basal metabolic rate (BMR) in osteoarthritis (OA) remains unclear, as previous retrospective studies have produced inconsistent results. Therefore, we performed a Mendelian randomization (MR) study to systematically investigate the causal relationship between the BMR and OA.

METHODS

Single-nucleotide polymorphism (SNP) data related to BMR and OA were collected in a genome-wide association study. Using OA as the outcome variable and BMR as the exposure factor, SNPs with strong correlation with the BMR as the tool variable were screened. The correlation between the BMR and OA risk was evaluated using the inverse-variance weighted method, and heterogeneity and pleiotropy were evaluated using a sensitivity analysis.

RESULTS

There was a potential causal relationship between the BMR and OA risk (odds ratio [OR], 1.014; 95% confidence interval [CI], 1.008-1.020; P = 2.29e - 6). A causal relationship was also revealed between the BMR and knee OA (OR, 1.876; 95% CI, 1.677-2.098; P = 2.98e - 28) and hip OA (OR, 1.475; 95% CI, 1.290-1.686; P = 1.26e - 8). Sensitivity analysis confirmed the robustness of these results.

CONCLUSION

Here, we identified a latent causal relationship between the BMR and the risk of OA. These results suggest that the risk of OA in the hip or knee joint may be reduced by controlling the BMR.

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.

Self-care behaviors in older adults suffering from knee osteoarthritis: Application of theory of planned behavior

Background

Osteoarthritis is one of the main reasons causing disablement. Educational intervention for self-care behaviors of patients suffering from knee osteoarthritis is important because its effect on quality of patient life decreases the economic burden of disorder on society and family. This study aimed to investigate the effect of educational intervention based on the theory of planned behavior (TPB) on promoting self-care behaviors in elderly patients suffering from knee osteoarthritis.

Methods

This quasi-experimental study was performed on 200 elderlies suffering from knee osteoarthritis in the rheumatology clinics of Shiraz, Iran, in 2019. The subjects were divided into two groups (100 experimental and 100 control). Before and after 4 months, both experimental and control groups filled a questionnaire. After administering a pre-test to both groups, only the experimental group was trained based on the TPB constructs on self-care behaviors in elderly people suffering from knee osteoarthritis in eight sessions by presenting educational films and images, power points, and group discussions for solving problems.

Results

The mean age of the experimental group was 67.25 ± 3.64, and the mean age of the control group was 66.12 ± 3.50. The average scores of attitudes, subjective norms, perceived behavioral control, intention, and behavior before the educational intervention did not have significant differences in experimental and control groups, however, 4 months after the educational intervention, the paired t-test indicated significant enhancement in every construct in the experimental group, but no significant changes in the control group.

Conclusion

According to the results, the educational intervention increased the self-care behaviors of patients suffering from knee osteoarthritis based on the theory of planned behavior. Therefore, the results of this study can be used in theory-based intervention strategies for self-care behaviors of patients suffering from knee osteoarthritis.

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.

Intra-articular Hymovis injection for managing hip OA in active sportsmen. A 24-month observational retrospective clinical investigation

BACKGROUND

Hip Osteoarthitis (OA) risk is sport-specific and depends on frequency, intensity, and type of mechanic stress the hip is subjected to. This retrospective observational study aims to investigate the safety and performance of Hymovis (HYADD-4) injection, a hexadecyl (C-16) HA-derivative, when used to manage symptomatic hip OA in active middle-aged sportsmen over a 24-month observation period.

METHODS

The retrospective analysis included clinical records of active sportsmen, aged between 40 and 65 years, and suffering from symptomatic Kellgren-Lawrence grade II to III hip OA, treated with two (24 mg/3 ml) Hymovis injections, two weeks apart, every 3-4 months, for two years. When available, data on MRI examination were included in the analysis as well as Heidelberg Sports Activity Score (HAS) and Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaires.

RESULTS

Thirty patients (56.4 ± 7.3 years) were included in the study, sixteen cyclists and 14 tennis players. For all patients, HAS and most HAGOS scores improved significantly (p < 0.05) at the first control visit (4 months) and further improved over time. For all other scores an important clinical benefit was experienced by more than 50% of participants. No adverse events were recorded.

CONCLUSION

Treatment of hip OA in active sportsmen with Hymovis seems a safe and effective approach for the management of OA symptoms, by potentially protecting cartilage and subchondral bone from further damage.

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.

An exploratory study to investigate the association between age, physical activity, femoral trochlear cartilage thickness and biomarkers of tissue metabolism in adult males

Purpose

To investigate the association between age, physical activity, femoral trochlear cartilage thickness and biomarkers of tissue metabolism in a cross-sectional sample of adult males. This study utilizes several emerging biomarkers that have been associated with early joint degenerative changes; serum COMP (cartilage oligomeric matrix protein), HA (hyaluronan) and lubricin.

Methods

Eighty-one males (age: mean (range): 43(18–70) years; body mass index: 25.2 (21.0–30.6) kg/m²) volunteered. Resting serum COMP, HA and lubricin concentrations were determined via commercially available enzyme-linked immunosorbent assay (ELISA) and femoral trochlear cartilage thickness via supra-patellar ultrasound imaging. Physical activity levels were assessed using questionnaires. Statistical analyses were performed using correlation and regression analyses.

Results

Age was correlated with lateral trochlear cartilage thickness (r = − 0.372; p < 0.01) and serum COMP (r = 0.342; p < 0.01). 7-day physical activity was correlated with serum COMP (r = 0.357, p < 0.01), and 12-month physical activity with both lateral trochlear cartilage thickness (r = 0.340, p = 0.01) and serum HA (r = 0.296, p < 0.05). Regression analyses revealed that age significantly accounted for the variability in lateral cartilage thickness and serum COMP, following the adjustment for potential cofounders. However, the association between age and lateral trochlear cartilage thickness was not moderated by physical activity levels (all p > 0.05).

Conclusion

This study indicates that older age may be associated with thinner lateral trochlear cartilage and higher cartilage turnover. Being physically active may also be positive for lateral trochlear cartilage thickness. However, overall, both age and physical activity level only account for a small amount of the variability in cartilage thickness and serum biomarkers.

Prevalence of and Risk Factors for Total Hip and Knee Replacement in Retired National Football League Athletes

BACKGROUND

Osteoarthritis is a substantial cause of disability. Joint replacement prevalence relates to the burden of severe osteoarthritis, and identifying risk factors for end-stage disease may indicate intervention opportunities. American football has high youth and elite participation, and determining risk factors for severe osteoarthritis may support future morbidity prevention.

PURPOSE

To (1) determine the prevalence of hip and knee replacement in retired National Football League (NFL) athletes, (2) examine risk factors for replacement, and (3) identify the association between knee injuries and knee replacement.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Retired NFL athletes who participated in a general health survey were included. This historical cohort included those playing between 1929 and 2001. The association between self-reported playing or injury history, and replacement after retirement, was assessed with prevalence ratios (PRs). Models were adjusted for potential confounders of age and weight.

RESULTS

Data for 2432 retired male NFL players (69.3% response rate) who had participated in football for a mean 15.2 years were included, in which 277 players reported replacement after retirement (11.4%). More participants reported knee replacement (7.7%) than hip replacement (4.6%). The majority of participants reported previous severe knee injury (53%), and the most prevalent was meniscal tear (32.2%). In multivariable models, age (10-year increase, PR, 2.23; 95% CI, 1.99-2.51), current weight (PR, 1.10; 95% CI, 1.06-1.14), and reporting 1 (PR, 1.78; 95% CI, 1.14-2.77), 2 (PR, 1.91; 95% CI, 1.16-3.15), or ≥3 knee injuries (PR, 3.44; 95% CI, 2.33-5.09) were associated with knee replacement. Age (10-year increase, PR, 1.86; 95% CI, 1.59-2.18), linemen (PR, 1.62; 95% CI, 1.03-2.55), and reporting 1 (PR, 1.72; 95% CI, 1.05-2.80), 2 (PR, 2.77 95% CI, 1.58-4.84), or ≥3 (PR, 2.44; 95% CI, 1.52-3.91) hip injuries were associated with hip replacement. Each reported knee injury type was cross-sectionally associated with replacement after retirement (P < .05).

CONCLUSION

Knee replacement was more prevalent than hip replacement. Risk factors differed between the hip and the knee, with age and severe joint injury associated with hip and knee replacement, weight with knee replacement, and playing position associated with hip replacement. Joint injury and weight management may be prevention opportunities to reduce morbidity and end-stage osteoarthritis in this population.

Ambulatory activity interacts with common risk factors for osteoarthritis to modify increases in MRI-detected osteophytes

OBJECTIVE

To investigate the longitudinal association between objectively measured ambulatory activity (AA) and knee MRI-detected osteophytes (OPs), and to test whether this relationship was modified by common risk factors for OA including sex, obesity, disease severity and knee injury history.

METHODS

408 community-dwelling adults aged 51-81 years were assessed at baseline and 2.7 years. T1-weighted fat-suppressed MRI was used to evaluate knee OPs at both time points. AA was assessed at baseline by pedometers and categorized as: less active (≤7499 steps per day), moderately active (7500-9999 steps per day) and highly active (≥10,000 steps per day).

RESULTS

Statistically significant interactions were detected between knee OA risk factors and AA on increases in MRI-detected OPs (all P < 0.05). In stratified analyses, being moderately active, compared to being less active, was protective against an increase in MRI-detected OPs (score change of ≥1) in females (relative risk (RR) = 0.42, 95%CI, 0.25-0.70, P < 0.01), those who were obese (RR = 0.50, 95%CI, 0.30-0.83, P < 0.01), those with radiographic OA (ROA) (RR = 0.68, 95%CI, 0.47-0.97, P = 0.02) and those with a history of knee injury (RR = 0.27, 95%CI, 0.08-0.88, P = 0.02) in almost every knee compartment, after adjustment for confounders. No statistically significant associations were found in males, non-obese, non-ROA or non-injury groups.

CONCLUSIONS

Being moderately active is protective against an increase in MRI-detected OPs in females, those with ROA, those who are obese and those with a history of knee injury. These findings suggest that being moderately active is beneficial for individuals who are at higher risk of knee OA.

Effects of a finger exercise program on hand function in automobile workers with hand osteoarthritis: A randomized controlled trial

Hand osteoarthritis reduces a person's ability to perform work activities and return to their occupation. We investigated the effects of a finger exercise program on hand grip strength, pain, physical function, and stiffness in automobile manufacturing workers with hand osteoarthritis. This randomized controlled trial was conducted on 29 subjects. Fifteen experimental subjects received a finger exercise program with paraffin baths, while 14 control subjects received only paraffin baths. Hand grip strength, pain, physical function, and stiffness were assessed at baseline and 8 weeks later. In the experimental group, hand grip strength (P < 0.001) and Australian/Canadian osteoarthritis hand index (AUSCAN) scores (pain, P < 0.001; stiffness, P < 0.001; physical function, P < 0.001) were significantly improved by 3.52 ± 2.03, 21.6 ± 8.3 (pain), 16.8 ± 10.21 (stiffness), and 13.86 ± 4.54 (physical function) compared with preintervention values. In the control group, hand grip strength (P = 0.004) and AUSCAN scores (pain, P < 0.001; stiffness, P = 0.019; physical function, P < 0.001) were significantly improved by 0.57 ± 0.62, 7.85 ± 5.46 (pain) 11.42 ± 7.18 (stiffness), and 10.28 ± 14.41 (physical function) compared with preintervention values. Significant differences between groups were found for postintervention hand grip strength (P = 0.015) and AUSCAN index subscale scores (pain, P < 0.001; physical function, P = 0.020). A combined finger exercise and paraffin bath program is effective in reducing pain, improving physical function, and increasing hand grip strength in workers with hand osteoarthritis.

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.

Acute Ankle Sprain in a Mouse Model: Changes in Knee-Joint Space

CONTEXT

  Ankle sprains remain the most common orthopaedic injury. Conducting long-term studies in humans is difficult and costly, so the long-term consequences of an ankle sprain are not entirely known.

OBJECTIVE

  To measure knee-joint space after a single surgically induced ankle sprain in mice.

DESIGN

  Randomized controlled trial.

SETTING

  University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Thirty male mice (CBA/2J) were randomly placed into 1 of 3 surgical groups: the transected calcaneofibular ligament (CFL) group, the transected anterior talofibular ligament/CFL group, or a sham treatment group. The right ankle was operated on in all mice.

MAIN OUTCOME MEASURE(S)

  Three days after surgery, all of the mice were individually housed in cages containing a solid-surface running wheel, and daily running-wheel measurements were recorded. Before surgery and every 6 weeks after surgery, a diagnostic ultrasound was used to measure medial and lateral knee-joint space in both hind limbs.

RESULTS

  Right medial (P = .003), right lateral (P = .002), left medial (P = .03), and left lateral (P = .002) knee-joint spaces decreased across the life span. The mice in the anterior talofibular ligament/CFL group had decreased right medial (P = .004) joint space compared with the sham and CFL groups starting at 24 weeks of age and continuing throughout the life span. No differences occurred in contralateral knee-joint degeneration among any of the groups.

CONCLUSIONS

  Based on current data, mice that sustained a surgically induced severe ankle sprain developed greater joint degeneration in the ipsilateral knee. Knee degeneration could result from accommodation to the laxity of the ankle or biomechanical alterations secondary to ankle instability. A single surgically induced ankle sprain could significantly affect knee-joint function.

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.

BIOMECHANICAL STUDY ON THE EFFECTS OF VARUS AND VALGUS DEFORMITIES OF THE KNEE ON THE WEIGHT-BEARING DOME OF ACETABULUM

This study's purpose was to investigate the biomechanical effects of varus and valgus knee deformities in different degrees on the acetabulum's weight-bearing dome. We collected six lower extremity specimens from three fresh adult male cadavers, including the L5 vertebral body, pelvis, bilateral hips, bilateral knees and lower leg sections. We visually examined all specimens and then X-rayed them to exclude the presence of hip and knee pathology. We adjusted the tibiofemoral angle to 180° (knee varus at 10°, Group A), 190° (knee varus at 20°, Group B), 160° (knee valgus at 10°, Group C) and 150° (knee valgus at 20°, Group D) using the external fixator, respectively, fixed them, respectively, and then monitored them through the above 3D laser scanning imager. We found the acetabulum's weight-bearing dome area, stress and stress distribution by loading and coloring on the pressure-sensitive film. We measured them using a FPD-305 density meter and FPD-306 pressure converter. We compared the areas, average stresses and peak stresses of the acetabulum's weight-bearing dome between groups B and D and group A, respectively. The differences between groups B and D had no significance. Compared to group A's area, average stress and peak stress, the areas of groups C and E decreased, and their average stresses and peak stresses increased significantly. The differences between groups B and C and groups D and E were also significant. Due to different degrees of knee varus and valgus angles, the areas of the weight-bearing acetabulum dome, average stress and peak stress are different. The knee varus and valgus at 20° were statistically significant, which may be the key pathogenesis of hip arthritis.

Relationship between physical activity and chronic musculoskeletal pain among community-dwelling Japanese adults

BACKGROUND

Both little and excessive physical activity (PA) may relate to chronic musculoskeletal pain. The primary objective of this study was to characterize the relationship of PA levels with chronic low back pain (CLBP) and chronic knee pain (CKP).

METHODS

We evaluated 4559 adults aged 40-79 years in a community-based cross-sectional survey conducted in 2009 in Shimane, Japan. We used self-administered questionnaires to assess sociodemographics and health status: PA was assessed by the International Physical Activity Questionnaire, and CLBP and CKP were assessed by a modified version of the Knee Pain Screening Tool. We examined relationships of PA with prevalence of CLBP and CKP using Poisson regression, controlling for potential confounders.

RESULTS

CLBP and CKP were both prevalent (14.1% and 10.7%, respectively) and associated with history of injury, medication use, and consultation with physicians. PA was not significantly related to CLBP or CKP (P > 0.05) before or after adjustment for potential confounders. For example, compared with adults reporting moderate PA (8.25-23.0 MET-hours/week), prevalence ratios for CKP adjusted for sex, age, education years, self-rated health, depressive symptom, smoking, chronic disease history, and body-mass index were 1.12 (95% confidential interval [CI] 0.84-1.50) among those with the lowest PA and 1.26 (95% CI 0.93-1.70) among those with the highest PA (P quadratic = 0.08). The prevalence ratios were further attenuated toward the null after additional adjustment for history of injury, medication use, and consultation (P quadratic = 0.17).

CONCLUSIONS

This cross-sectional study showed that there were no significant linear or quadratic relationships of self-reported PA with CLBP and CKP. Future longitudinal study with objective measurements is needed.

Physical activity in relation to knee cartilage T2 progression measured with 3 T MRI over a period of 4 years: data from the Osteoarthritis Initiative

OBJECTIVE

The purpose of this study was to analyze the longitudinal association between physical activity levels and early degenerative cartilage changes in the knee, measured using T2 relaxation times over a period of 4 years in individuals without clinical or radiographic evidence of OA.

DESIGN

Cartilage T2 was measured at baseline and after 2 and 4 years in 205 subjects aged 45-60 years from the Osteoarthritis Initiative (OAI) incidence and normal cohorts with no knee pain (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score of zero), and a Kellgren Lawrence (KL) score of <2 at baseline. Physical activity was scored using the Physical Activity Scale for the Elderly (PASE) questionnaire, which was obtained yearly over 4 years. The relationship between physical activity and T2 was studied using a mixed model linear regression, including random effects, and adjusted for age, sex, and body mass index (BMI).

RESULTS

T2 values for all PASE tertiles progressed over the 4-year period. T2 progression was increased in the highest tertile of physical activity compared to the mid-tertile at the medial tibia (MT) (P = 0.041), patella (Pat) (P = 0.019), and average T2 of all knee compartments combined (P = 0.033). Subjects with the lowest 15% PASE scores showed significantly higher T2 progression compared to the mid-level physical activity group at the lateral femur (LF) (P = 0.025), lateral tibia (LT) (P = 0.043), medial femur (MF) (P = 0.044), tibiofemoral compartment (P = 0.017), patellofemoral compartment (P = 0.016), lateral compartments (P = 0.003), and average of all compartments (P = 0.043).

CONCLUSION

High and very low PASE scores were associated with greater progression of cartilage T2 measurements in asymptomatic, middle-aged individuals, suggesting accelerated cartilage matrix biochemical degeneration over time.

Physical activity, alignment and knee osteoarthritis: data from MOST and the OAI

OBJECTIVE

To determine the effect of physical activity on knee osteoarthritis (OA) development in persons without knee injury and according to knee alignment.

DESIGN

We combined data from Multicenter Osteoarthritis (MOST) and Osteoarthritis Initiative (OAI), studies of persons with or at high risk of OA. Subjects had long limb and repeated posteroanterior knee radiographs and completed the physical activity survey for the elderly (PASE). We studied persons without radiographic OA and excluded knees with major injury and without long limb films. We followed subjects 30 months (in MOST) and 48 months (in OAI) for one of two incident outcomes: (1) symptomatic tibiofemoral OA (radiographic OA and knee pain), or (2) tibiofemoral narrowing. 'Active' persons were those with PASE score in the highest quartile by gender. We examined risk of OA in active group using logistic regression adjusting for age, gender, body mass index (BMI), Western Ontario and McMaster Arthritis Index (WOMAC) pain score, Kellgren and Lawrence (KL) grade (0 or 1), and study of origin. We also analyzed knees from malaligned and neutrally aligned limbs.

RESULTS

The combined sample comprised 2,073 subjects (3,542 knees) with mean age 61 years. The cumulative incidence of symptomatic tibiofemoral OA was 1.12% in the active group vs 1.82% in the others (odds ratio (OR) among active group 0.6, 95% confidence interval (CI) 0.3, 1.3). Joint space narrowing occurred in 3.41% of knees in the active group vs 4.04% in the others (OR among active group 0.9 (95% CI 0.5, 1.5)). Results did not differ by alignment status.

CONCLUSIONS

Physical activity in the highest quartile did not affect the risk of developing OA.

Effect of long-term vigorous physical activity on healthy adult knee cartilage

INTRODUCTION

Whether participation in long-term vigorous physical activity affects knee cartilage is unclear and may depend on the state of knee health. We examined the association between vigorous physical activity during a decade and the subsequent changes in knee cartilage among healthy adults. We then examined whether this effect differed in those with and without bone marrow lesions (BMLs), as an indicator of preclinical joint damage.

METHODS

A total of 297 healthy adults age 50-79 yr were recruited. Physical activity was assessed via questionnaire at baseline (1990-1994) and at follow-up (2003-2004), and a score for persistence of vigorous physical activity score was determined. Each subject underwent knee magnetic resonance imaging in 2003-2004 and in 2006-2007. Cartilage volume, defects, and BMLs were measured using validated methods.

RESULTS

Persistent participation in vigorous physical activity was associated with worsening of medial knee cartilage defects (odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.0-2.3). In the subgroup with BMLs, but not in those without BML, persistent vigorous physical activity was associated with a significant worsening of medial knee cartilage defects (OR = 3.4, 95% CI = 1.0-16.5) and a trend toward an increased rate of loss of medial knee cartilage volume (21.6 mm·yr, 95% CI = -0.4 to 43.6).

CONCLUSIONS

In knees with BMLs, persistent participation in vigorous physical activity was associated with adverse cartilage changes in the medial compartment. This suggests that the long-term effects of vigorous physical activity may depend on the preexisting health of the joint.

The association between objectively measured physical activity and knee structural change using MRI

OBJECTIVES

This study describes the longitudinal association between objectively assessed physical activity (PA) and knee structural change measured using MRI.

METHODS

405 community-dwelling adults aged 51-81 years were measured at baseline and approximately 2.7 years later. MRI of the right knee at baseline and follow-up was performed to evaluate bone marrow lesions (BMLs), meniscal pathology, cartilage defects, and cartilage volume. PA was assessed at baseline by pedometer (steps/day).

RESULTS

Doing ≥10 000 steps/day was associated with BML increases (RR 1.97, 95% CI 1.19 to 3.27, p=0.009). Participants doing ≥10 000 steps/day had a 1.52 times (95% CI 1.05 to 2.20, p=0.027) greater risk of increasing meniscal pathology score, which increased to 2.49 (95% CI 1.05 to 3.93, p=0.002) in those with adverse meniscal pathology at baseline. Doing ≥10 000 steps/day was associated with a greater risk of increasing cartilage defect score in those with prevalent BMLs at baseline (RR 1.36, 95% CI 1.03 to 1.69, p=0.013). Steps/day was protective against volume loss in those with more baseline cartilage volume but led to increased cartilage loss in those with less baseline cartilage volume. (p=0.046 for interaction).

CONCLUSIONS

PA was deleteriously associated with knee structural change, especially in those with pre-existing knee structural abnormalities. This suggests individuals with knee abnormalities should avoid doing ≥10 000 steps/day. Alternatives to weight-bearing activity may be needed in order to maintain PA levels required for other aspects of health.

Is lifelong knee joint force from work, home, and sport related to knee osteoarthritis?

Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the "cumulative peak force index", a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA.

Physical activity is associated with magnetic resonance imaging-based knee cartilage T2 measurements in asymptomatic subjects with and those without osteoarthritis risk factors

OBJECTIVE

To evaluate the association of exercise and knee-bending activities with magnetic resonance imaging (MRI)-based knee cartilage T2 relaxation times and morphologic abnormalities in asymptomatic subjects from the Osteoarthritis Initiative, with or without osteoarthritis (OA) risk factors.

METHODS

We studied 128 subjects with knee OA risk factors and 33 normal control subjects ages 45-55 years, with a body mass index of 18-27 kg/m(2) and no knee pain. Subjects were categorized according to exercise level, using the leisure activity component of the Physical Activity Scale for the Elderly, and by self-reported frequent knee-bending activities. Two radiologists graded the cartilage of the right knee on MR images, using the Whole-Organ MRI Score (WORMS). Cartilage was segmented, and compartment-specific T2 values were calculated. Differences between the exercise groups and knee-bending groups were determined using multiple linear and logistic regression models.

RESULTS

Among subjects with risk factors for knee OA, light exercisers had lower T2 values compared with sedentary and moderate/strenuous exercisers. When the sexes were analyzed separately, female moderate/strenuous exercisers had higher T2 values compared with sedentary individuals and light exercisers. Subjects without risk factors displayed no significant differences in T2 values according to exercise level. However, frequent knee-bending activities were associated with higher T2 values in both subjects with OA risk factors and those without OA risk factors and with more severe cartilage lesions in the group with risk factors.

CONCLUSION

In subjects at risk of knee OA, light exercise was associated with low T2 values, whereas moderate/strenuous exercise in women was associated with high T2 values. Higher T2 values and WORMS grades were also observed in frequent knee-benders, suggesting greater cartilage degeneration in these individuals.

Influence of lifetime hip joint force on the risk of self-reported hip osteoarthritis: a community-based cohort study

OBJECTIVE

To investigate the influence of cumulative lifetime hip joint force on the risk of self-reported medically-diagnosed hip osteoarthritis (OA).

DESIGN

Prospective cohort.

SETTING

General population.

PARTICIPANTS

Members of Canadian Association of Retired Persons, community-dwelling.

MAIN OUTCOME

Health-professional diagnosed hip OA, self-reported.

METHODS

Exposure data on lifetime physical activity type (occupational, household, sport) and dose (frequency, intensity, duration) was collected in 2005. Subjects were ranked in terms of a 'cumulative peak force index' (CFPI), a measure of lifetime mechanical hip joint force. Multivariable survival analyses were performed to obtain adjusted effects for mean lifetime exposure and during 5-year age periods.

RESULTS

Of 2918 subjects aged 45-85, 176 (6.03%) developed hip OA during the 2-year follow up (43 men, 133 women). The highest quintile of mean lifetime hip CPFI (HR 2.32; 95% CI 1.31-4.12), and high hip force in three age periods (35-39, 40-44, 45-49) were independently associated with hip OA. Previous hip injury was an approximate five-fold risk for development of hip OA across all models. In analysis by activity domain (occupation, sport, household), there was a trend (non-significant) for the highest quintile of occupational force, but not sport or household, to be associated with hip OA.

CONCLUSIONS

A newly proposed measure of lifetime mechanical hip force was used to estimate the risk of self-reported, medically-diagnosed hip OA. While there are important limitations, this prospective study suggests that lifelong physical activity is generally safe. Very high levels of lifetime force from all domains combined, and in particular from occupational forces, may be important in the etiology of hip OA.

Functional adaptation of knee cartilage in asymptomatic female novice runners compared to sedentary controls. A longitudinal analysis using delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC)

OBJECTIVE

To longitudinally estimate the change in glycosaminoglycan content of knee cartilage in asymptomatic untrained female novice runners participating in a Start To Run program (STR) compared to sedentary controls.

METHOD

Nine females enrolling in a 10-week STR and 10 sedentary controls participated voluntarily. Prior to and after the 10-week period, both groups were subjected to dGEMRIC imaging. dGEMRIC indices of knee cartilage were determined at baseline and for the change after the 10-week period in both groups. Based on a self-reported weekly log, physical activity change during the study was depicted as decreased, unchanged or increased. The Mann-Whitney U and Kruskal-Wallis tests were applied to test the hypotheses that dGEMRIC changes occurred between groups and according to physical activity changes respectively.

RESULTS

No significant differences were established between groups for dGEMRIC indices at baseline (P=0.541). A significant positive change of the median dGEMRIC index in the runners group was demonstrated when compared to the controls [+11.66ms (95% CI: -25.29, 44.43) vs -9.56ms (95% CI: -29.55, 5.83), P=0.006]. The change in dGEMRIC index differed significantly according to physical activity change (P=0.014), showing an increase in dGEMRIC index with increasing physical activity.

CONCLUSION

Since cartilage appears to positively respond to moderate running when compared to a sedentary lifestyle, this running scheme might be considered a valuable tool in osteoarthritis prevention strategies. Caution is warranted when applying these results to a wider population and to longer training periods.

Lifetime trajectory of physical activity according to energy expenditure and joint force

OBJECTIVE

To develop and demonstrate the feasibility of a method for estimating lifetime hip and knee cumulative joint force using survey data on physical activity, and to construct and describe lifetime trajectories of energy expenditure and hip and knee joint force.

METHODS

Exposure data on lifetime physical activity, including type (occupational, household, and recreation) and dose (frequency, intensity, and duration), were collected from a Canada-wide population study of adults ages ≥45 years. Subjects were ranked in 2 ways: in terms of physical activity-related energy expenditure and in terms of a cumulative peak force index (CPFI) for the hip and knee, which is a measure of lifetime exposure and is a time/joint force product involving years of force and subject bodyweight. A relative joint loading index was calculated as the ratio of joint force (CPFI score) to energy expenditure.

RESULTS

A total of 4,269 subjects completed the baseline measurements. Lifetime energy expenditure and hip and knee CPFI scores were higher for occupational and household activity than sport. The mean lifetime energy expenditure from total physical activity in the study sample was 119.1 metabolic equivalent-hours/week. Women had slightly higher total lifetime energy expenditure and CPFI scores than men. The relative joint loading index was highest for male household and sport activity and lowest for female occupational activity.

CONCLUSION

Lifetime cumulative hip/knee joint force trajectories were successfully constructed from survey data and followed expected trends. Comparing energy expenditure with joint force revealed variation by age, sex, and activity type, indicating these measures may help distinguish the numerous benefits of physical activity from possible risks.

Is physical activity a risk factor for primary knee or hip replacement due to osteoarthritis? A prospective cohort study

OBJECTIVE

To estimate prospectively any association between measures of physical activity and the risk of either primary knee or hip replacement due to osteoarthritis (OA).

METHODS

Eligible subjects (n = 39,023) were selected from participants in a prospective cohort study recruited 1990-1994. Primary knee and hip replacement for OA during 2001-2005 was determined by linking the cohort records to the National Joint Replacement Registry. A total physical activity level was computed, incorporating both intensity and frequency for different forms of physical activity obtained by questionnaire at baseline attendance.

RESULTS

There was a dose-response relationship between total physical activity level and the risk of primary knee replacement [hazards ratio (HR) 1.04, 95% CI 1.01-1.07 for an increase of 1 level in total physical activity]. Although vigorous activity frequency was associated with an increased risk of primary knee replacement (HR 1.42, 95% CI 1.08-1.86) for 1-2 times/week and HR 1.24 (95% CI 0.90-1.71) for ≥ 3 times/week), the p for trend was marginal (continuous HR 1.08, 95% CI 1.00-1.16, p = 0.05). The frequency of less vigorous activity or walking was not associated with the risk of primary knee replacement, nor was any measure of physical activity associated with the risk of primary hip replacement.

CONCLUSION

Increasing levels of total physical activity are positively associated with the risk of primary knee but not hip replacement due to OA. Physical activity might affect the knee and hip joints differently depending on the preexisting health status and anatomy of the joint, as well as the sort of physical activity performed.

Osteoarthritis in Women: Effects of Estrogen, Obesity and Physical Activity

Arthritis is the leading cause of physical disability in the USA and osteoarthritis (OA), the most common form, affects nearly 27 million people. Women have a higher prevalence of OA than men, but the underlying causes for the increased susceptibility of women to OA are not fully understood. This review discusses the associations of sex hormones, obesity and physical activity with the incidence and progression of OA in women. Although many studies have explored the relationships of estrogen and reproductive history with the risk of OA or joint replacement, there is no consensus on the role of these factors. Obesity clearly increases risk for OA, but whether obesity affects women and men differently is uncertain. Moderate levels of physical activity do not appear to increase the incidence or progression of OA and may even have a weak protective effect. Future investigations should focus on sex-specific mechanisms for the development of OA and determine whether there are modifiable factors (e.g., estrogen, obesity, physical activity) that can be targeted through prevention and treatment strategies to mitigate the increased incidence and prevalence of OA in women.

Subjects with higher physical activity levels have more severe focal knee lesions diagnosed with 3T MRI: analysis of a non-symptomatic cohort of the osteoarthritis initiative

PURPOSE

To study the prevalence of focal knee abnormalities using 3 Tesla (T) magnetic resonance (MR) studies in relation to physical activity levels in asymptomatic, middle-aged subjects from the osteoarthritis initiative (OAI).

MATERIAL AND METHODS

We analyzed baseline data from 236, 45-55 years old individuals (136 women, 100 men) without knee pain (based on Western Ontario and McMaster University scores) and a body mass index (BMI) of 19-27 kg/m(2). Physical activity levels were determined in all subjects using the Physical Activity Scale for the Elderly (PASE). MR imaging (MRI) at 3T was performed using coronal intermediate-weighted (IW) 2D fast spin-echo (FSE), sagittal 3D dual-echo in steady state (DESS) and 2D IW fat-suppressed (fs) FSE sequences of the right knee. All images were analyzed by two musculoskeletal radiologists identifying and grading cartilage, meniscal, ligamentous and other knee abnormalities using the whole-organ MR imaging score (WORMS) MRI OA scoring method. Statistical significances between subjects with different activity levels were determined using one-way analysis of variance (ANOVA), chi-square tests and a multi-variate regression model adjusted for gender, age, BMI, Kellgren-Lawrence (KL) score and osteoarthritis (OA) risk factors.

RESULTS

Meniscal lesions were found in 47% of the 236 subjects, cartilage lesions in 74.6%, bone marrow edema pattern (BMEP) in 40.3% and ligament lesions in 17%. Stratification of subjects by physical activity resulted in an increasing incidence of cartilage, meniscus and ligament abnormalities, BMEP and joint effusion according to activity levels (PASE). The severity grade of cartilage lesions was also associated with PASE levels and presence of other knee abnormalities was also significantly associated with cartilage defects.

CONCLUSION

Asymptomatic middle-aged individuals from the OAI incidence cohort had a high prevalence of knee abnormalities; more physically active individuals had significantly more and more severe knee abnormalities independently of gender, age, BMI, KL score and OA risk factors. These data therefore also suggest that subjects with higher physical activity levels may be at greater risk for cartilage, meniscus and ligament abnormalities, but the analysis of the longitudinal data will show whether these subjects will demonstrate accelerated progress.

Individual and occupational risk factors for knee osteoarthritis: results of a case-control study in Germany

INTRODUCTION

A number of occupational risk factors are discussed in relation to the development and progress of knee joint diseases (for example, working in a kneeling or squatting posture, lifting and carrying heavy weights). Besides the occupational factors, a number of individual risk factors are important. The distinction between work-related and other factors is crucial in assessing the risk and in deriving preventive measures in occupational health.

METHODS

In a case-control study, patients with and without symptomatic knee osteoarthritis (OA) were questioned by means of a standardised questionnaire complemented by a semi-standardised interview. Controls were matched and assigned to the cases by gender and age. Conditional logistic regression was used in analysing data.

RESULTS

In total, 739 cases and 571 controls were included in the study. In women and men, several individual and occupational predictors for knee OA could be described: obesity (odds ratio (OR) up to 17.65 in women and up to 12.56 in men); kneeling/squatting (women, OR 2.52 (>8,934 hours/life); men, 2.16 (574 to 12,244 hours/life), 2.47 (>12,244 hours/life)); genetic predisposition (women, OR 2.17; men, OR 2.37); and sports with a risk of unapparent trauma (women, OR 2.47 (>or=1,440 hours/life); men, 2.58 (>or=3,232 hours/life)). In women, malalignment of the knee (OR 11.54), pain in the knee already in childhood (OR 2.08), and the daily lifting and carrying of loads (>or=1,088 tons/life, OR 2.13) were related to an increased OR; sitting and smoking led to a reduced OR.

CONCLUSIONS

The results support a dose-response relationship between kneeling/squatting and symptomatic knee OA in men and, for the first time, in women. The results concerning general and occupational predictors for knee OA reflect the findings from the literature quite well. Yet occupational risks such as jumping or climbing stairs/ladders, as discussed in the literature, did not correlate with symptomatic knee OA in the present study. With regards to occupational health, prevention measures should focus on the reduction of kneeling activities and the lifting and carrying of loads as well as general risk factors, most notably the reduction of obesity. More intervention studies of the effectiveness of tools and working methods for reducing knee straining activities are needed.

Risk factors for onset of osteoarthritis of the knee in older adults: a systematic review and meta-analysis

OBJECTIVE

Knee osteoarthritis (OA) is common in older adults. Determination of risk factors for onset of knee OA may help in its prevention. The objective of this systematic review, and meta-analysis, was to determine the current evidence on risk factors for knee OA.

DESIGN

A systematic literature search was carried out for cohort and case-control studies evaluating the association of demographic, comorbid, and other patient-determined factors with onset of knee OA. A scoring tool was developed to assess the quality of studies. Heterogeneity of studies was examined. Where possible studies were pooled to give an overall estimate of the association of factors with onset of knee OA.

RESULTS

Of the 2233 studies screened, 85 were eventually included in the review. Study quality tended to be moderate. The main factors consistently associated with knee OA were obesity (pooled OR 2.63, 95% CI 2.28-3.05), previous knee trauma (pooled OR 3.86, 95% CI 2.61-5.70), hand OA (pooled OR 1.49, 95% CI 1.05-2.10), female gender (pooled OR 1.84 95% CI 1.32-2.55) and older age. Smoking appeared to have a moderate protective effect, however this was not evident once the analysis was restricted to cohort studies only.

CONCLUSIONS

Whilst certain factors have been extensively reviewed (for example, body mass index), more longitudinal studies are needed to investigate the association of physical occupational and other patient-determined factors with future knee OA. The quality of such studies also needs to be improved. However, there are identifiable factors which can be targeted for prevention of disabling knee pain.

Risk Factors for Occupational Osteoarthritis

Sixteen articles published between 1987 and 2008 regarding work-related activities as risk factors for osteoarthritis of the knee, hand, foot, hip, and cervical spine were chronologically reviewed. Despite challenges (e.g., nonresponse bias, inadequate sample size, and retrospective exposure assessment), the review findings indicated a strong relationship between physical strain experienced while performing physically demanding jobs and the incidence of osteoarthritis. This conclusion informs occupational health nurses' work and design of work policies.

Systematic review of the prevalence of radiographic primary hip osteoarthritis

Hip osteoarthritis is a common cause of musculoskeletal pain in older adults and may result in decreased mobility and quality of life. Although the presentation of hip osteoarthritis varies, surgical management is required when the disease is severe, longstanding, and unresponsive to nonoperative treatments. For stakeholders to plan for the expected increased demand for surgical procedures related to hip osteoarthritis, including arthroplasty, it is important to first understand its prevalence. We conducted a systematic review by searching MEDLINE and EMBASE to identify recent English language articles reporting on the prevalence of radiographic primary hip osteoarthritis in the general adult population; references including studies and primary studies from previous systematic reviews were also searched. This strategy yielded 23 studies reporting 39 estimates of overall prevalence ranging from 0.9% to 27% with a mean of 8.0% and a standard deviation of 7.0%. Heterogeneity was noted in study populations, eligibility criteria, age and gender distribution, type of radiographs, and method of diagnosis. Although the association between radiographic hip osteoarthritis and the need for eventual surgical management is still unclear, this study supports assertions that hip osteoarthritis is a prevalent condition whose treatment will continue to place important demands on health services.

Epidemiology of hip and knee pain in a community based sample of Italian persons aged 65 and older

OBJECTIVE

To describe prevalence, characteristics and correlates of hip pain (HP) and knee pain (KP) in an Italian community based cohort aged 65 and older (65+).

METHOD

Baseline survey (1998-2000), population-based study in the Chianti area (Tuscany, Italy); 1299 persons aged 65+ were selected from the city registry of Greve in Chianti and Bagno a Ripoli (multistage sampling method); 1006 participants (564 women and 442 men, age 75.2+/-7.1) provided information for this analysis. Persons reporting HP/KP in the past 4 weeks were recorded and their Western Ontario and McMaster University Osteoarthritis Index pain score (WPS-range 0-20) calculated. Potential correlates of HP/KP, including clinical, lifestyle and psycho-social features and physical measures, were tested in age- and gender-adjusted regression analyses and then entered a multivariate regression model.

RESULTS

HP was reported by 11.9% participants, while 22.4% reported KP and 7.2% both conditions. Climbing/descending stairs and walking were the activities eliciting more severe pain in either condition. Average WPSs were 5.6+/-3.5 for HP and 5.4+/-10.4 for KP. Both HP and KP were related to back pain, reduced hip abduction, reduced muscle power and increased trunk flexibility. HP was also related to KP and poor self-rated health (SRH), while KP to HP, foot pain, high body mass index, reduced knee passive flexion and knee extension torque, low education.

CONCLUSION

In a community sample of an Italian persons aged 65+, the prevalence of KP almost doubled that of HP. While both conditions were related to pain in other joints and specific joint impairment, only HP was related to poor SRH, and only KP to mechanical overload.

Cumulative hip contact stress predicts osteoarthritis in DDH

Hip stresses are generally believed to influence whether a hip develops osteoarthritis (OA); similarly, various osteotomies have been proposed to reduce contact stresses and the risk of OA. We asked whether elevated hip contact stress predicted osteoarthritis in initially asymptomatic human hips. We identified 58 nonoperatively treated nonsubluxated hips with developmental dysplasia (DDH) without symptoms at skeletal maturity; the control group included 48 adult hips without hip disease. The minimum followup was 20 years (mean, 29 years; range, 20-41 years). Peak contact stress was computed with the HIPSTRESS method using anteroposterior pelvic radiographs at skeletal maturity. The cumulative contact stress was determined by multiplying the peak contact stress by age at followup. We compared WOMAC scores and radiographic indices of OA. Dysplastic hips had higher mean peak contact and higher mean cumulative contact stress than normal hips. Mean WOMAC scores and percentage of asymptomatic hips in the study group (mean age 51 years) were similar to those in the control group (mean age 68 years). After adjusting for gender and age, the cumulative contact stress, Wiberg center-edge angle, body mass index, but not the peak contact stress, independently predicted the final WOMAC score in dysplastic hips but not in normal hips. Cumulative contact stress predicted early hip OA better than the Wiberg center-edge angle.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Factors that may mediate the relationship between physical activity and the risk for developing knee osteoarthritis

Studies investigating the effect of physical activity on risk for developing osteoarthritis at weight-bearing joints have reported conflicting results. We examine evidence to suggest that this may be due to the existence of subgroups of individuals who differ in their response to physical activity, as well as methodological issues associated with the assessment of knee joint structure and physical activity. Recommendations for future studies of physical activity and the development of knee osteoarthritis are discussed.

Effect of physical activity on articular knee joint structures in community-based adults

OBJECTIVE

It is unclear whether physical activity that is beneficial for the cardiovascular system is detrimental to knee structures. We examined the association between intensity, frequency, and duration of physical activity and knee structures in a community-based population.

METHODS

A total of 297 healthy adults ages 50-79 years with no history of knee injury or disease were recruited from an existing study on healthy aging. Each subject underwent knee magnetic resonance imaging (MRI) to measure tibial cartilage volume, tibiofemoral cartilage defects, and bone marrow lesions. Physical activity and anthropometric data were obtained via questionnaire during 1990-1994 and 2003-2004.

RESULTS

Tibial cartilage volume increased with frequency (P = 0.01) and duration (P = 0.001) of vigorous activity (activity leading to diaphoresis or dyspnea) reported 10 years previously, as well as recent vigorous activity in the 7 days prior to MRI (P = 0.05). Recent weight-bearing vigorous activity increased with tibial cartilage volume (P = 0.02) and was inversely associated with cartilage defects (P = 0.02). A reduced risk of bone marrow lesions was associated with regular walking (P = 0.04).

CONCLUSION

Vigorous physical activity appears to have a beneficial effect on knee articular cartilage in healthy, community-based adults with no history of knee injury or disease. Regular walking reduces the risk of bone marrow lesions in the knee. This study provides further support for a beneficial effect of physical activity for diseases associated with aging and suggests that exercise that is good for the heart is also good for the knees.

The cross-sectional relationship between fortnightly exercise and knee cartilage properties in healthy adult women in midlife

OBJECTIVE

Exercise has been strongly promoted for the prevention of the major diseases of aging in women, such as cardiovascular disease and osteoporosis. However, conflicting data exist as to whether exercise benefits joint health and thus helps protect against degenerative processes such as knee osteoarthritis. The aim of this study was to examine the cross-sectional relationship between exercise and knee joint cartilage in women at midlife.

DESIGN

A total of 176 women aged 40 to 67 years with no clinical knee osteoarthritis or history of significant knee injury were recruited from the community and had magnetic resonance imaging performed on their dominant knee to assess tibial cartilage volume and defects. The women completed a questionnaire to determine fortnightly exercise participation and frequency.

RESULTS

Fortnightly participation in exercise at an intensity that caused tachypnea and an increased pulse rate for at least 20 minutes was positively associated with the volume of the medial tibial cartilage (P=0.02). There was a tendency for the frequency of exercise at this intensity to be positively associated with medial tibial cartilage volume (P=0.07). Exercise participation was not significantly associated with the presence of knee cartilage defects.

CONCLUSIONS

Participation in exercise that causes tachypnea and an increased pulse rate for at least 20 minutes was associated with greater medial tibial cartilage volume, but not knee cartilage defects in non-healthcare-seeking women at midlife. More frequent exercise also tended to be associated with greater medial tibial cartilage volume. Although our findings need to be confirmed longitudinally, they provide further support for a beneficial effect of regular exercise on diseases related to aging.

Finger osteoarthritis and differences in dental work tasks

Mechanical load has been proposed as a risk factor for hand osteoarthritis. Dentists produce high manual forces in their work tasks. We studied whether the pattern of dental work tasks was associated with finger osteoarthritis. Radiographs of both hands of 291 middle-aged female dentists were examined for the presence of osteoarthritis. Patterns of dental work tasks during work history were empirically defined by cluster analysis. Three patterns emerged reflecting high, moderate, and mild task variation. Age, specialization, years in clinical work, various activities requiring hand use, family history of Heberden's nodes, body mass index, and smoking were accounted for in logistic regression analyses. The dentists with a history of low task variation had a greater prevalence of osteoarthritis in the thumb, index, and middle fingers compared with dentists with high variation (OR 2.22; 95%CI 1.04-4.91). The pattern of dental work task history is associated with the localization of osteoarthritis in the fingers.

The Role of Mechanical Loading in the Onset and Progression of Osteoarthritis

Osteoarthritis is a progressive joint disease characterized by an imbalance of articular cartilage biosynthesis and degradation attributed to both inflammatory and biomechanical factors. Whereas moderate mechanical loading appears necessary for maintaining healthy cartilage, abnormal joint loading increases the risk of osteoarthritis. Obesity-induced osteoarthritis and the benefits of physical activity may be mediated by systemic levels of proinflammatory mediators as well as local biomechanical factors in the joint.

Hand use and patterns of joint involvement in osteoarthritis. A comparison of female dentists and teachers

OBJECTIVES

To investigate the effect of mechanical stress on finger osteoarthritis (OA) by comparing women from two occupations with different hand load but the same socio-economic grade, and to investigate whether hand load may affect the pattern of joint involvement in OA.

METHODS

Radiographs of both hands of 295 dentists and 248 teachers were examined. Each interphalangeal (distal, proximal and thumb interphalangeal) and the metacarpophalangeal joints were graded (0 = no OA, 4 = severe OA) separately by using reference images. The co-involvement of different hand joints was analysed by logistic regression.

RESULTS

The distal interphalangeal joints were the most frequently involved joints. The non-dominant hand was more frequently affected by OA of grade 2 or more than the dominant hand. The prevalence of OA of grade 2 or more in any finger joint and also in any distal interphalangeal joint was higher among the teachers compared with the dentists (59 vs 48%, P = 0.020 and 58 vs 47%, P < 0.010 respectively). Finger OA showed more clustering in the ring and little fingers and more row clustering and symmetry in the teachers than in the dentists [age-adjusted odds ratio (OR) = 1.57, 95% confidence interval (CI) 1.10-2.23, OR = 1.84, 95% CI 1.28-2.64, and OR = 1.98, 95% CI 1.38-2.86 respectively]. The OR of more severe OA (grade 3 or more) in the right-hand thumb and the index and middle fingers was significantly elevated among the dentists compared with the teachers (OR 2.61, 95% CI 1.03-6.59).

CONCLUSION

Our findings indicate that finger OA in middle-aged women is highly prevalent and often polyarticular. Hand use may have a protective effect on finger joint OA, whereas continuing joint overload may lead to joint impairment.

High contact hip stress is related to the development of hip pathology with increasing age

BACKGROUND

High contact hip stress is believed to be one of the key biomechanical factors involved in the hip cartilage degeneration and osteoarthritis. Accordingly, with increasing age high contact hip stress is expected to cause elimination of subjects from the population of healthy hips, but its predictive value has not been evaluated so far. The objective of the paper is to investigate whether the exposure of healthy hips to estimated high contact hip stress is related to the development of hip pathology with increasing age.

METHODS

A cross-sectional age- and gender-matched analysis of the peak contact hip stress calculated from pelvic geometry was made in 103 adult subjects with healthy hips. The peak contact hip stress was calculated from anterior-posterior pelvic radiographs of healthy hips by using a mathematical model of the human hip in the static one-legged stance.

FINDINGS

In both female and male population, the average values of the peak contact hip stress normalized to the body weight are significantly higher and the values are also more dispersed in younger subjects when compared to older subjects.

INTERPRETATION

The hip joints which remain healthy in the old age have lower average estimated peak contact hip stress. These results are consistent with the explanation that subjects with high estimated peak contact hip stress are more likely to develop hip disease in the course of life.