Bone mineral density and bone turnover in patients with knee osteoarthritis compared with generalized osteoarthritis

The aim of this study was to investigate bone mineral density (BMD) and bon e turnover in patients with primary knee osteoarthritis (KOA) and to compar e them with generalized OA (GOA) and nonGOA patients. A total of 88 postmen opausal primary KOA patients were studied. OA was graded by using knee radi ographs. BMD of the lumber spine, femur, and radius, and biochemical marker s of bone turnover, pyridinoline (Pyr), deoxypyridinoline (Dpyr), CTx, and osteocalcin were compared among each grade. BMD was also compared with 88 n ormal controls who were age and weight-matched. In 88 KOA patients, 56 were divided into 28 GOA and 28 non-GOA groups by grading hand radiographs. BMD and biochemical markers were compared between GOA and non-GOA. KOA patient s had higher BMD at several skeletal sites compared with age- and weight-ma tched normals. A significant difference of BMD between each grade was obser ved between grades 0-1 and 3 (0.774 +/- 0.143 versus 0.940 +/- 0.185 g/cm(2 ), P < 0.001), grades 2 and 3 (0.781 +/- 0.125 Versus 0.940 +/- 0.185 g/cm( 2), P < 0.01) in the spine, and between grades 0-1 and 3 (0.505 +/- 0.100 v ersus 0.563 +/- 0.127 g/cm(2), P < 0.05) in the trochanter. A significant d ifference of biochemical bone markers was observed between grades 0-1 and 3 (P < 0.05) and between grades 2 and 3 (P < 0.05) in Pyr and grades 0-1 and 3 (P < 0.05) and between grades 1 and 4 (P < 0.05) in Dpyr, but not in ost eocalcin and CTx. GOA patients had higher BMD of the spine (0.902 +/- 0.175 versus 0.747 +/- 0.138 g/cm(2), P < 0.01), trochanter (0.535 +/- 0.107 ver sus 0.480 +/- 0.107 g/cm(2), P < 0.05), and one-third of the radius (0.526 +/- 0.068 versus 0.472 +/- 0.089 g/cm(2), P < 0.05) and had significantly h igher biochemical markers in Pyr and Dpyr than non-GOA patients. It is conc luded that KOA patients had higher BMD at several skeletal sites. Biochemic al bone markers were influenced by some degree of cartilage damage in OA pa tients. This tendency was stronger in GOA patients than in non-GOA patients .