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| Allan Gelber, M.D.
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Abstract 596: Barometric Pressure and Ambient Temperature Influence Osteoarthritis Pain. Results of a National Web-Based Prospective Study Background: It is very often the case that patients with osteoarthritis relate to their doctors the perception that weather conditions influence their joint-related symptoms. Evidence to support this claim has, however, previously been conflicting. Methods:To address this putative relationship, of how weather conditions may be related to osteoarthritis pain perceptions, the investigators studied participants of the Online Glucosamine Trial. This 3-month, online, randomized clinical trial was conducted among 205 participants residing in 41 states across the United States. In each of these geographic locations, meteorological conditions were independently ascertained using data from the National Oceanic and Atmospheric Administration, by linking the participants' zip codes with weather recordings from the most proximate weather station to each participant's location of residence. Values for ambient temperature, barometric pressure, precipitation and dewpoint were recorded for each day of the 3 month period in the glucosamine trial. Results:The investigators evaluated the relationship of joint pain, using the WOMAC pain scale, to the meteorological conditions and found a weak, inverse association of temperature with pain, and a positive association of change in barometric pressure with pain levels. The strongest association, in multivariate analysis, was with barometric pressure. In contrast, precipitation levels and dewpoint were not related to joint pain. Editorial Comment:Of particular interest to patients and physician alike, this study underscores the common perception that changes in barometric pressure are in fact related to perceived changes in joint pain. | ||
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Abstract 598: The Impact of Gender on Varus-Valgus Laxity in Knees With and Without Osteoarthritis Background: Women are known to develop osteoarthritis of the knee more often than men. In recent years, an additional recognized risk factor for osteoarthritis, distinct from gender, has been knee malalignment. The concept of varus-valgus laxity is that excessive side-to-side shifting of the tibia upon the femur, which diminishes the fit of opposing joint surfaces, creates increased shear and compression forces across the knee joint. Methods: The investigators sought to determine whether greater varus-valgus laxity is present among women than in men, which might explain the recognized role of gender as a risk factor for knee OA. This study specifically examined whether women have greater laxity than men, among 3 groups of participants: those without knee OA, those with possible knee OA, and those with established knee OA. 551 women and 325 men with knee OA or at risk to develop knee OA were studied. Of note, a device that provides constant varus and valgus load at a fixed knee flexion angle, with the thigh and ankle immobilized, was used to determine the angle of knee joint laxity. Mean age of the participants was 62 years, who were on average obese. Results: The investigators found that in each of the 3 groups of participants, women more often demonstrated knee laxity than men. In fact, among those with definite radiographic evidence of knee osteoarthritis, there was a two-fold greater frequency [odds ratio 2.08; 95% CI 1.08-4.00] of high knee laxity (defined as > 6.750) in women than in men, after adjustment for age, BMI, strength and physical activity. A greater than two-fold greater risk for laxity in women was also observed among those participants without radiographic evidence of osteoarthritis. Editorial Comment: These findings suggest that the presence of excess laxity in women than in men, may account for the greater predilection of women to development osteoarthritis of the knee. | ||
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Abstract 599: Do Body Composition and Body Fat Distribution Explain Ethnic Differences in Radiographic Knee Osteoarthritis Outcomes in African -American and Caucasian Women? Background: African American women have been observed to have a greater prevalence of knee osteoarthritis than Caucasian women. One explanation for this observed difference in prevalence rates, by race, has been unbalanced distribution in body mass index between the two racial groups. Methods: In the present study, the investigators explored whether differences in body composition and fat distribution might account for the observed differences in prevalence of knee OA. Women from the first follow-up assessment in the Johnston County Osteoarthritis Project in North Carolina were assessed; having undergone dual energy x-ray absorptiometry (DEXA) evaluations, with evaluation of fat, lean and bone mass composition. A total of 849 women were evaluated. Results: The African American women were twice as likely to have radiographic evidence of knee osteoarthritis [odds ratio 1.5; 95% CI 1.11-2.16]. Editorial Comment: Of note, each of the body composition and fat distribution variables fully explained the observed racial differences in prevalence of knee OA. However, the observed measures of body composition did not explain as well the racial differences prevalence of bilateral, and of more advanced, knee osteoarthritis. | ||
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Abstract 564: Meniscectomy of the Knee is Associated with Increased Risk of Patellomoral Osteoarthritis
Background: Joint injury, including torn menisci and cruciate ligaments, have previously been related to a heightened risk of developing osteoarthritis of the knee. An important contributing component to this relationship has been the role of meniscectomy, arising from the surgery pursued to treat the injury, as opposed to a direct role from the injury itself, via damage to cartilaginous structures, has been postulated. Moreover, this investigative team, from Sweden, has previously shown that surgical meniscectomy is related to an increase in risk of incident osteoarthritis of the knee, affecting the tibiofemoral compartments. They now explore this link with regard to osteoarthritis of the patellofemoral compartment. Methods: To address this question, Englund and Lohmander evaluated 315 patients who had undergone isolated meniscal resection 15-22 years previously. The reference group was comprised of 68 non-operated persons identified from the Swedish National Population Records. Radiographs were obtained of the 3 knee compartments and of the hands on these participants. Results: The study revealed that radiographic evidence of osteoarthritis was more frequent among the patients with prior meniscectomy, than among the non-operated persons from the national records database. Of note, radiographic osteoarthritis of the patellofemoral compartment was present 2.5 times more often among the group with, than among those without, prior medial meniscectomy surgery [odds ratio 2.5; 95% CI 1.0-6.3]. This risk was even higher [OR 5.4; 95%CI 1.9 - 15.4] among those with prior lateral meniscectomy. Editorial Comment: These finding once again demonstrate a link between prior meniscectomy and future knee joint OA, this time evident at the patellofemoral compartment. What still remains unclear, however, is whether it is the surgical procedure (meniscectomy) or direct deleterious effects of injury to joint health that contribute to the heightened risk of developing osteoarthritis of the knee joint in those with antecedent knee injuries. | ||
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Abstract 838: Risk factors for imminent progression of knee osteoarthritis (OA) Introduction: Determining the factors which predict radiographic progression in OA is important for future clinical investigation in the field especially as potential structure modifying therapies are assessed. The following two studies evaluated patients from two different interventional clinical trials, one a 16 month, 319 patient, NIH-sponsored study, the second a 24 month, 2400 patient, industry sponsored study of risedronate Abstract 838: Results: The recruited patients were obese (mean BMI 33.7 +/- 7.7 kg/m2) and predominantly female (84%). In this study, age, sex, race, and BMI were not predictive of progression. The presence of patellofemoral OA was associated with the highest odds ratio of progression of both medial JSN and osteophyte growth. Similarly baseline knee pain, stiffness, and function assessed by the WOMAC scales were associated with progression of JSN and osteophyte growth. Comment: The method to assess progression could be criticized for its semiquantitative nature. That this was developed with consensus is reassuring; however, a specified definition of progression of joint space narrowing may have been a more precise method to define the outcome. It is somewhat surprising that traditional risk factor of BMI was not associated with progression in this study however the population had an overall higher BMI than has been reported in other OA clinical studies perhaps biasing the result. The finding that patellofemoral disease was associated with the highest risk of progression (OR 1.76 for JSN, OR 1.58 for osteophytes) is an important finding as patellofemoral views are not necessarily part of the standard evaluation for knee OA. Although in this study patient assessments of pain, stiffness, and function were predictive of progression, in no case was the OR greater than 1.2, indicating a smaller effect. Abstract 254: Results: The study population was obese with a baseline mean BMI of 30 kg/m2. Only 13.2% of the patients in the study showed radiographic progression in the medial joint space over the two years of the study. Small numbers of patients progressed at a very rapid rate (up to 2 mm/2 years). The odds ratio for progression were greatest for baseline levels of CTXII in the third or fourth quartile of measurements (>267) (OR 2.38 and 2.29 respectively, p<0.01). Male gender (accounting for 30% of the study population) was also associated with progression with an OR 1.86. A baseline level of pain as assessed by the WOMAC was also predictive with an OR of 1.2 per 10 mm of pain. Knee crepitus was also associated with progression with an OR 1.59. Obesity was only modestly associated with progression (OR 1.03) and had a lower risk than seen in longitudinal studies. A trend was observed for patients with the most significant baseline JSN showing more progression was also demonstrated (p=0.07). Comment: This is the largest longitudinal study to date of patients with knee osteoarthritis assessed by a standardized, highly reproducible radiographic method. It is important to note that in all patients with knee OA enrolled in this study, only a small number went on to show radiographic progression at two years. Even though no treatment effect was demonstrated in the primary symptomatic or radiographic endpoints, the pooling of patients from different treatment groups is one potential confounder in the analysis presented. However the size of the study may allow further assessments of the progressors even in the placebo treated patients though the numbers will be smaller. These results importantly continue to support the fact that baseline levels of cartilage degradation markers may be important in assessing patients at risk of progression. This study supports the results found by Mazzuca above with knee crepitus, perhaps reflecting patellofemoral disease, was also a predictor. Clinical assessment of pain was important as well as shown by others. Whether other imaging modalities and baseline features will further help to determine those who progress remain to be studied. This study demonstrates that importance of enriching a population of OA patients for "progressors" in order to demonstrate a medication treatment effect for structure modification. | ||
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