The relationship between total collagen and extractable collagen pool. Total collagen was measured as hydroxyproline per wet weight and extractable collagen pool was expressed as a percentage of total amount of collagen. Open and closed circles represent OA and reference groups, respectively.
Hosseininia et al. BMC Musculoskeletal Disorders 2013 14:18 doi:10.1186/1471-2474-14-18