Objective Women are disproportionately affected by musculoskeletal disorders. Parous women appear to be at particularly elevated risk for structural and functional changes in the lower limbs. The combination of increased weight on joints with potentially greater laxity during pregnancy could lead to permanent structural changes in feet. Although arches may become lax during pregnancy, it is unknown whether changes persist. The objective of this study was to determine whether arch height loss persists postpartum. Design Forty-nine women completed this longitudinal study. Static and dynamic arch measurements were collected in first-trimester and at 19 weeks postpartum. Linear mixed models were used to determine whether outcome measures significantly changed overall or by parity. Results Arch height and rigidity index significantly decreased, with concomitant increases in foot length and arch drop. The first pregnancy accounted for the reduction in arch rigidity and increases in foot length and arch drop. No changes were detected in the center of pressure excursion index. Conclusions Pregnancy appears to be associated with a permanent loss of arch height and the first pregnancy may be the most significant. These changes in the feet could contribute to the increased risk for musculoskeletal disorders in women. Further research should assess the efficacy of rehabilitative interventions for prevention of pregnancy-related arch drop.

Background Leg length inequality is common in the general population and may accelerate development of knee osteoarthritis. Objective To determine if leg length inequality is associated with prevalent, incident and progressive knee osteoarthritis, Design Prospective observational cohort study. Setting Subjects recruited from the community in Birmingham, AL and Iowa City, IA Patients 3026 subjects, age 50-79, with or at high risk for knee osteoarthritis. Measurements The exposure was leg length inequality measured from full limb radiographs. The outcomes were prevalent, incident, and progressive knee osteoarthritis. Radiographic osteoarthritis was defined as Kellgren and Lawrence grade ≥2 and symptomatic osteoarthritis was defined as radiographic disease in a consistently painful knee. Results Leg length inequality ≥1 cm was associated with prevalent radiographic (53% vs. 36%, OR 1.9, 95%CI 1.5-2.4) and symptomatic (30% vs. 17%, OR 2.0, 95%CI 1.6-2.6) osteoarthritis in the shorter limb. Inequality ≥1 cm was associated with incident symptomatic osteoarthritis in the shorter (15% vs. 9%, OR 1.7, 95%CI 1.2-2.4) and longer (13% vs. 9%, OR 1.5, 95%CI 1.0-2.1) limb. Inequality ≥1 cm was associated with increased odds (29% vs. 24%, OR 1.3, 95%CI 1.0-1.7) of progressive osteoarthritis in the shorter limb. Limitations The duration of follow-up may not be long enough to adequately identify cases of incidence and progression. Measurements of leg length, including radiographic, have measurement error which could result in misclassification. Conclusions Radiographic leg length inequality was associated with prevalent, incident symptomatic and progressive knee osteoarthritis. These results point to leg length inequality as a potentially modifiable risk factor for knee osteoarthritis. Primary Funding Source National Institute on Aging

Trunk and lower extremity loss of muscle mass and central obesity may be risk factors for chronic low back pain without a positive straight leg raise test result in women aged 45 to 69 years. Arch Intern Med. 2000;160:3265-3269.

There exist no large-series human data linking contact stress exposure to an articular joint's propensity for developing osteoarthritis because contact stress analysis for large numbers of subjects remains impractical. The speed and simplicity of discrete element analysis (DEA) for estimating contact stresses makes its application to this problem highly attractive, but to date DEA has been used to study only a small numbers of cases. This is because substantial issues regarding its use in population-wide studies have not been addressed. Chief among them are developing fast and robust methods for model derivation and the selection of boundary conditions, establishing accuracy of computed contact stresses, and including capabilities for modeling in-series structural elements (e.g., a meniscus). This article describes an implementation of DEA that makes it feasible to perform subject-specific modeling in articular joints in large population-based studies. Keywords computational joint modeling; osteoarthritis; contact stressThe development of expeditious methods suitable for determining in vivo articular contact stress distributions is critical to understanding normal articular function and the mechanopathology of osteoarthritis (OA). Excessive functional loads habitually applied to at-risk joints (shoulder, wrist, hip, knee, ankle) can negatively impact the health of articular cartilage, eventually leading to degeneration (Buckwalter & Brown, 2004). Many computational models have been developed to determine contact stresses in a variety of joints, mostly using finite element analysis (FEA) . For the most part, however, these studies have involved lengthy and concerted efforts in well-controlled research settings, and have yielded articular contact stresses for only small numbers of cases. The high logistical cost of performing 3-D contact FEA on a subject-or patient-specific basis makes FEA of limited attraction for stress analysis in large epidemiologic studies (Englund et al., 2007;Felson & Nevitt, 2004;Lester, 2008). Advancement of expeditious methods for determining in vivo articular contact stress distributions will enhance the understanding of normal articular function, and of the mechano-pathology of OA. Chao and colleagues popularized the use of rigid body spring modeling (now commonly known as discrete element analysis, or DEA) in biomechanics, as a simple numerical framework to model articular contact (An et al., 1990;Genda et al., 2001;Iwasaki et al., 1998;Li et al., 1994;Volokh et al., 2007). The DEA formulation involves treating bones as rigid bodies, and the cartilage at a given joint as an array of compressive-only springs distributed over the articulating bone surfaces. This modeling approach has been used to study contact mechanics in various diarthrodial joints, most recently progressing to fully 3D subject-specific geometry (Elias & Cosgarea, 2007;Elias et al., 2004;Iwasaki et al., 1998). However, it has rarely been used to study large numbers of cases. To our knowledge, the largest 3-D ...

Purpose Chronic upper extremity disability (UED) is common after breast cancer treatment but under-identified and under-treated. Although UED has been linked to quality of life (QoL), the role of UED as mediator between contemporary treatment practices and QoL has not been quantified. This investigation describes UED in a contemporary sample of breast cancer patients and examines its relationship with personal and treatment factors and QoL. Methods Eight hundred and thirty-three women diagnosed at eight medical institutions during 2013–2014 with microscopically confirmed ductal carcinoma in situ or invasive stage I–III breast cancer were surveyed an average of 22 months after diagnosis. UED was measured with a modified QuickDASH and QoL with the FACT-B. The questionnaire also collected treatments, sociodemographic information, comorbidity, body mass index, and a 3-item health literacy screener. Results Women who received post-mastectomy radiation and chemotherapy experienced significantly worse UED and QoL. Women who had lower income, lower health literacy and prior diabetes, arthritis or shoulder diagnoses had worse UED. Patients with worse UED reported significantly worse QoL. Income and health literacy were independently associated with QoL after adjustment for UED but treatment and prior conditions were not, indicating mediation by UED. UED mediated 52–79% of the effect of mastectomy-based treatments on QoL as compared with unilateral mastectomy without radiation. UED and QoL did not differ by type of axillary surgery or post-mastectomy reconstruction. Conclusions A large portion of treatment effect on QoL is mediated by UED. Rehabilitation practices that prevent and alleviate UED are likely to improve QoL for breast cancer survivors.