OSTEOARTHRITIC CARTILAGE CONTAINS INCREASED CALCIUM, MAGNESIUM AND PHOSPHORUS

  • 1 August 1987
    • journal article
    • research article
    • Vol. 14  (4) , 806-810
Abstract
Using plasma emission spectroscopy, we measured the calcium (Ca), phosphorus (P), magnesium (Mg), and sulphur (S) concentration in femoral head cartilage from 7 patients with osteoarthritis (OA) and 22 normal patients. We found that in OA cartilage Ca = 271.9 .+-. 32.7 mmol/kg dry weight compared to Ca = 113.2 .+-. 12.6 mmol/kg dry weight in normal controls. The Ca:P molar ratio in OA cartilage was 1.93 compared to Ca:P = 2.27 in normals, and Ca:P = 1.67 in apatite crystals. We conclude that OA cartilage has a greater binding capacity for Ca, Mg, and P than does normal cartilage. Apatite crystals, if present, comprise maximally 0.4% wet weight of OA cartilage.