The association of BMI and knee pain among persons with radiographic knee osteoarthritis: a cross-sectional study.

BACKGROUND: Many people with radiographic knee osteoarthritis (RKOA) do not present with pain. It is suspected that such persons tend toward lower body mass index (BMI). The purpose of the study was to explore the relationship between BMI and knee pain among persons with RKOA. METHODS: Subjects in the Clearwater Osteoarthritis Study with RKOA (N = 576) were classified as reporting knee pain (Pain) or no knee pain (No Pain). WHO-classified BMI categories were compared by pain status. Odds ratios were calculated for the four elevated BMI groups, with the normal BMI group as the reference group. Elevated BMI was the risk factor, and knee pain status was the outcome factor. RESULTS: Pain subjects presented with a higher mean BMI (30.4 kg/m2) compared with No Pain subjects (27.5 kg/m2) (p < 0.0001). Unadjusted and adjusted odds ratios demonstrated a positive association between BMI group and pain for each successive elevated BMI category. Adjusted odds ratios ranged from 1.6 for the Pre-obese group (p < 0.05) to 7.5 for the Obese III group (p < 0.0001). CONCLUSION: Among subjects with RKOA, those presenting with an elevated BMI had a greater likelihood of knee pain compared to subjects with a normal BMI, and this chance rose with each successive elevated BMI category. As BMI is a modifiable risk factor, longitudinal research is needed to confirm these findings and elucidate the mechanisms underlying this relationship.

The effects of strength training among persons with hand osteoarthritis: a two-year follow-up study.

Hand exercise is recommended for hand osteoarthritis (OA) management, but few efficacy studies have been published. The purpose of the study was to determine the effects of two years of whole body strength training and gripper exercise on hand strength, pain, and function in adults with radiographic evidence of hand OA. Older adults (N=55; 71.5+/-6.5 years; 80% female) participated in a two-year, three times per week strength training regimen. Bilateral gripper exercise weight (i.e., isotonic grip strength), isometric grip strength, pain, and self-reported hand, and finger function were recorded at baseline and 24 months. Isotonic grip strength increased 1.94 kg (20.14 kg baseline, 22.09 kg follow-up; p<0.0003). Right and left isometric grip increased 3.62 kg (25.83 kg baseline, 29.45 kg follow-up; p<0.002) and 2.95 kg (22.73 kg baseline, 25.65 kg follow-up; p<0.0005), respectively. Hand pain decreased from 4.77 to 2.62 (p<0.006). Hand and finger function scores showed minimal dysfunction at baseline and follow-up. Results suggest strength training safely increases dynamic and static grip strength and reduces pain in older persons with hand OA.

Exercise and osteoarthritis: are we stopping too early? findings from the Clearwater Exercise Study.

The value of exercise for people with knee osteoarthritis (OA) receives continuing consideration. The optimal length of study follow-up time remains unclear. A group of individuals with knee OA participating in an exercise intervention was followed for 2 years. The authors quantified the change in knee-pain scores during Months 1-12 and during Months 13-24. Eleven individuals with radiographic knee OA and knee-pain scores of 2+ were evaluated. Pain scores were collected weekly from participants who exercised three times a week. Participants demonstrated pain reduction during both time periods. Pain reduction during Months 13-24, -10.7%, was slightly higher than pain reduction during Months 1-12, -7.8%. Among people with knee OA who exercise, these findings suggest that knee-pain amelioration continues beyond 12 months. Clinicians should consider encouraging long-term exercise programs for knee-OA patients. To best characterize the effect of exercise on knee pain, researchers designing clinical trials might want to lengthen the studies' duration.

Positive hindfoot valgus and osteoarthritis of the first metatarsophalangeal joint.

BACKGROUND: The aim of this retrospective cohort study was to evaluate the association between increased hindfoot valgus and the subsequent development of osteoarthritis of the first metatarsophalangeal (MTP) joint. Specifically, our hypothesis was that among individuals free from first MTP joint osteoarthritis, those who have positive hindfoot valgus are more likely to develop first MTP joint osteoarthritis than are those individuals with normal hindfoot alignment. METHODS: Our sample consisted of 1592 men and women, 40 years of age or older, participating in the Clearwater Osteoarthritis Study (1988 to 2001). Biennial physical examinations, including serial radiographs, were conducted. The Kellgren and Lawrence ordinal scale was used to determine radiographic evidence (grades 2+) of the study outcomes and incidence of first MTP joint osteoarthritis. Standing hindfoot valgus was assessed visually by a registered nurse, with a hindfoot valgus measurement of more than 5 degrees classified as a positive hindfoot valgus. RESULTS: Individuals with hindfoot valgus were 23% more likely to subsequently develop first MTP joint osteoarthritis than were those without hindfoot malalignment (risk ratio = 1.23; p-value < 0.006). This risk estimate reflects the potential influence of age, gender, and body mass index. CONCLUSIONS: Our data suggest that hindfoot valgus may increase the risk of developing foot osteoarthritis. The association of hindfoot valgus with first MTP joint osteoarthritis in this epidemiological assessment is supportive of the mechanical theory for the development of osteoarthritis. The authors speculate that future, related studies may determine that osteoarthritis prevention strategies can be broadened to include individuals with positive hindfoot valgus.

Effect of regular exercise on the radiographic progression of foot osteoarthritis.

Among the elderly, osteoarthritis often causes chronic pain and disability. Although research has addressed the association between exercise and osteoarthritis, few studies have examined the effect of exercise on the radiographic progression of osteoarthritis. We investigated the relationship between ongoing exercise and radiographic progression of foot osteoarthritis. The first metatarsophalangeal and medial cuneiform-first tarsometatarsal joints were assessed. Joint-specific osteoarthritis radiographic progression scores were determined using four assessments: joint space narrowing, osteophytes, sclerosis, and a composite score. This cohort study included a subset of 221 men and women aged 40 to 91 years participating in a community-based osteoarthritis study. Adjusted risk estimates (95% confidence intervals) summarizing the relationship between ongoing exercise and radiographic progression in the first metatarsophalangeal joint ranged from 0.34 (0.11-0.99) for osteophytes to 0.66 (0.23-1.92) for sclerosis; because only eight individuals experienced medial cuneiform-first tarsometatarsal joint progression, these estimates were less stable, ranging from 2.41 (0.49-11.83) for composite to 4.29 (0.11-166.52) for osteophytes. Overall, our findings do not suggest that regular exercise is a risk factor for foot osteoarthritis progression. Future replication studies are warranted to confirm these findings.

The association of radiographic foot osteoarthritis and radiographic osteoarthritis at other sites.

OBJECTIVE: To quantify the association between radiographic foot osteoarthritis (OA) and radiographic OA at four joints: second distal interphalangeal (DIP), third proximal interphalangeal (PIP), first carpometacarpal (CMC), and the knee. METHODS: Data collected for the Clearwater Osteoarthritis Study (COS) were analyzed (N=3436). The study outcome was first metatarso-phalangeal joint (first MTP) OA status. The predictor variables were second DIP, third PIP, first CMC, and knee OA. The Kellgren and Lawrence scale determined OA status. The strength of the association between foot OA and other sites was further explored by unilateral and bilateral categories. RESULTS: For both genders, we found a significant, positive relationship between grade 2+ foot OA and second DIP, third PIP, first CMC, and knee OA. This relationship maintained its significance after adjustment for age, body mass index, and occupational history. Adjusted odds ratios ranged from 3.2 for the second DIP joint (P<0.0001) to 3.7 for the knee joint (P<0.0001). Relative to unilateral joint disease, co-existing bilateral disease yielded a significantly elevated risk for foot OA for all joints examined. While other studies have not specifically examined co-occurrence with foot OA, our findings are consistent with results from related studies. CONCLUSIONS: There is a dearth of studies exploring foot OA. Our findings support the theory of a systemic etiology involved in the development of OA. Future epidemiological studies that further distinguish the relationship between OA at differing sites will provide an enhanced ability to describe the respective influences of mechanical and systemic factors in the development of this disease.

The association between medication usage and dropout status among participants of an exercise study for people with osteoarthritis.

BACKGROUND AND PURPOSE: Little is known about predictors of dropout status in exercise studies for people with osteoarthritis. Losses to follow-up can pose serious threats to study validity. The purpose of this study was to assess the ability of arthritis medication usage the month prior to enrollment to predict dropout status among participants in an exercise study for people with osteoarthritis. SUBJECTS AND METHODS: Men and women who participated in an exercise study for people with osteoarthritis (N=143) were followed. Participants who completed 24+ months of the exercise program were considered retained, whereas individuals who withdrew prior to 24 months were considered dropouts. RESULTS: Of the 143 participants analyzed, 78 (55%) completed 24+ months of the exercise program and 65 (45%) dropped out. Among those who reported arthritis medication usage, 54% were lost to follow-up. The group reporting no usage of arthritis medication had a 20% dropout rate (odds ratio=3.5, 95% confidence interval=1.6-7.6). The final adjusted model controlling for baseline health status, body mass index, and the interaction between baseline health status and body mass index indicated that those individuals who reported arthritis medication usage were more than 4 times more likely to drop out than were those who reported no arthritis medication usage (odds ratio=4.5, 95% confidence interval=1.8-11.4). DISCUSSION AND CONCLUSION: The results showed that self-reported arthritis medication usage the month prior to study enrollment was associated with subsequent dropout status among this group of exercisers with osteoarthritis. Further identification of baseline characteristics predictive of participant dropout status may benefit future exercise studies. A priori knowledge of "at-risk" exercise study participants will afford the opportunity for the timely allocation of appropriate resources aimed at reducing losses to follow-up.