BONE-STRUCTURE AND TURNOVER IN THE DISTAL RADIUS AND ILIAC CREST - A HISTOMORPHOMETRIC STUDY

In bone grafting procedures of the wrist, the distal radius would be a more convenient graft donor site than the conventionally used iliac c rest. We compared tetracycline-labeled bone biopsies hum these two sit es in 18 white patients (12 males, 6 females, aged 26-66 years) underg oing bone grafting procedures of the wrist. Fourteen had had previous trauma, 1 osteonecrosis of the lunate, 2 mild rheumatoid arthritis, an d I a brachial plexus palsy. The specimens were processed undecalcifie d and examined by routine histomorphometry for bone structure, static and dynamic bone turnover variables, and marrow cellularity. We found that bone from the distal radius had thinner cortices (p = 0.0001), lo wer bone volume (p = 0.01), thinner trabeculae (p = 0.029), greater tr abecuIar separation (p = 0.015), and lower wall thickness (p = 0.0001) , marrow cellularity (p = 0.0001), osteoid volume (p = 0.01), osteoid surface (p = 0.02), osteoid thickness (p = 0.0002), osteoblast surface (p = 0.001), eroded surface (p 0.01), osteoclast surface (p = 0.012), mineral apposition rate (p = 0.0002), double-labeled surface (p = 0.0 005), single-labeled surface (p = 0.006), bone formation rate (p = 0.0 005), adjusted apposition rate (p = 0.0001), longer mineralization lag time (p = 0.012), and greater activation frequency (p = 0.003). Prolo nged mineralization lag time in the radius was associated with thin os teoid seams and low adjusted apposition rates and was therefore attrib utable to a low level of osteoblast activity rather than to osteomalac ia. We conclude that bone hum the distal radius was structurally infer ior to and had lower turnover than the iliac crest bone. We suggest th at ,where a graft has to provide immediate structural integrity, the i liac crest is the preferred donor site. However, where bone graft is t o be compacted into a small cavitary defect, distal radial bone may be an adequate alternative. A clinical. study is needed to confirm this assumption.