Diabetes Mellitus and Limited Joint Mobility in the Upper Extremity

Diabetes mellitus (DM) affects about 25 million people in the United States. Musculoskeletal complications, especially those related to the upper extremity, are common and understudied in people with DM. Limited joint mobility (LJM) is a systemic complication of DM believed to be caused by thickening and stiffness of periarticular connective tissue due to non-enzymatic accumulation of advanced glycation end-products (AGEs), and resultant cross-link formation in the collagen. Specific implications of these structural changes on movement in people with DM are not known. The objectives of this research were to characterize the upper extremity movement impairments and limited joint mobility in people with diabetes mellitus and to understand the relationships between AGEs, structural changes and movement impairments on pain and disability in people with DM. In Chapter 2, we examine the severity of upper extremity pain/disability, weakness and limited joint mobility in a group of people diagnosed with DM attending an outpatient clinic. We report that a striking majority of the patients with DM complained of shoulder pain and/or disability, and that they had significant reductions in their shoulder range of motion, strength and hand function measures as compared to non-DM controls. Further, these measures were related to the pain and/or disability. In Chapter 3, we examine the differences in shoulder movement using 3-dimensional kinematics. We report substantial loss of humerus relative to scapula motion, in particular, external rotation motion during elevation and rotation movements. In Chapter 4, we examine the differences and relationships between a marker for AGEs, shoulder structural changes, movement, and pain and/or disability. We report that the proxy measure for skin AGEs, tendon thickness, movement impairments were higher in the DM group as compared to controls and these measures were related to complaints of pain and disability. In summary, our data indicate that shoulder and hand impairments are frequent, severe and often associated with pain and disability. Shoulder LJM, in particular humerus relative to scapula external rotation ROM, and strength deficits are significantly large in these individuals with DM as compared to matched control participants. These studies, for the first time, examine the relationship between an AGEs marker and functional measures as they relate to upper extremity impairments and LJM in people with DM