Epiphyseal plate

In attempting to reconcile these findings, it should be pointed out that rats may not be appropriate models for the study of calcium metabolism in humans. Unlike humans, the rat does not undergo epiphyseal plate closure and does not have a significant haversian remodeling sequence (21) Furthermore, rats excrete only l-270 of their calcium intake in their urine whereas humans excrete approximately 20-30% or more. This fact is especially significant, since most of the known effects of phosphates on calcium retention in humans are effected by alterations in urinary calcium. 

Thybeig, J., Friberg, U. Ultrastructure and phosphatase activity of matrix vesicles and cytoplasmic dense bodies in the epiphyseal plate. J. Ultrastruct. Res. 33, 554 (1970)... 

Brighton, G T., Heppenstall, R. B. Oxygen tension in zones of the epiphyseal plate, the metaphysis and diaphysis. An in vitro and in vivo study in rats and rabbits. J. Bone Joint Surg. 53A. 719 (1971)... 

Controls secondary male sex characteristics Maintains functional competence of male reproductive ducts and glands Increases protein anabolism maintains spermatogenesis inhibits follotropin Increases male sex behavior increases closure of epiphyseal plates... 

In children Androgens can cause growth disturbances resulting from premature closing of the epiphyseal plates and abnormal sexual maturation. 

Vitamin D deficiency in adults cannot affect the epiphyseal plate, as it has disappeaced, but it can prevent normal mineralization of the osteoid layer in bone that turns over. In vitamin D deficiency the osteoclasts continue to create tunnels and pits in the bone. The osteoblasts continue to synthesize the protein matrix however, complete mineralization of the osteoid may not occur. The result is osteomalacia - This disease may present as bone pain about the hips. Osteomalacia can be diagnosed using a bone biopsy, A sample is taken from the iliac crest — the hip bone. An abnormally wide osteoid is indicative of the disease. X-rays can also be used to diagnose osteomalacia, which is characterized by arrays or zones of tiny fractures in sucli bones as the pelvis and femur. 

Postnikov SS, Nazhimov VP, Semykin Sin, Kapranov NI. [Comparative morphological analysis of the articnlar cartilage, epiphyseal plate, spongy bone, and synovial membrane of the knee joint in children treated and not treated with ciprofloxacin.]Antibiot Khimioter 2000 45(11) 9-13. 

Bone Toxicity. In addition to its effect on calcium absorption, excess absorbed strontium adversely affects bone development in several ways, leading to the development of rickets in children and young animals. Strontium binds directly to hydroxyapatite crystals, which may interfere with the normal crystalline structure of bone (Storey 1961). In addition, excess strontium may prevent the normal maturation of chondrocytes in the epiphyseal plates of long bones (Matsumoto 1976). Excess strontium apparently interferes with the mineralization of complexed acidic phospholipids that is thought to help initiate the formation of hydroxyapatite crystals in developing bone (Neufeld and Boskey 1994). As a result, affected bone contains an excess of complexed acidic phospholipid and a significantly lower ash weight. 

There are other metabolic affects associated with chronic corticosteroid use including redistribution of fat giving the typical moon face and buffalo hump hyperglycaemia and possible diabetes protein loss from skeletal muscles with wasting and weakness increased bone metabolism leading to osteoporosis and growth inhibition in children due to early closure of the epiphyseal plates in long bones. 

In epiphyseal plate cartilage growth and mineralization, nor in the mineralization process of bone. Of considerable Interest is that the vitamin D-deficient animals infused with calcium and phosphorus accumulated calcium and phosphorus in their bones to a much greater extent than animals given vitamin D. O This probably is the result of a failure of the resorption process in vitamin D deficiency, and suggests that vitamin D must play an Important role in the bone modeling and remodeling process. 

Our surgical technique to ACL deficiency is what is called anatomic ACL reconstruction for most of the cases. The exception is the patients with wide open epiphysis and multiple-ligament reconstruction cases. For the patients with wide open epiphysis, we try to avoid the epiphyseal plate injury by approaching from outside-in technique for the femoral side that makes double-bundle reconstruction difficult (Fig. 24.1). For the cases with multiple-ligament reconstruction, we try to... 

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