Impact of comorbidities on the measurement of health in patients with ankle osteoarthritis. - Saltzman CL; Zimmerman MB; O'Rourke M; Brown TD; Buckwalter JA; Johnston R; Saltzman, Charles L; Zimmerman, M Bridget; O'Rourke, Michael; Brown, Thomas D; Buckwalter, Joseph A; Johnston, Richard (Journal of Bone & Joint Surgery, American Volume, 2006)