The Journal of Bone and Joint Surgery, Vol 61, Issue 8 1217-1220, Copyright © 1979 by Journal of Bone and Joint Surgery, Inc
Bone-mineral content, surface hardness, and mechanical fixation in the human radius. A correlative study
JE Trader, RP Johnson and JH Kalbfleisch
The bone-mineral content of seventeen intact forearms from eleven cadavera
was determined by the non-invasive photon-absorptiometric scanning
technique (Norland-Cameron Bone-Mineral Analyzer). Each radius was then
removed and three surgical screws were implanted. The forces required to
push out the screws retrograde were used to represent the security of
mechanical fixation and were correlated with bone-surface hardness and
bone-mineral content. A high degree of correlation (r = 0.89 or more) was
found between bone-mineral content and the force required for extraction. A
much lower correlation existed between surface hardness and extraction
force (r = 0.30). We concluded that surface hardness does not correlate
well with the screw-holding capacity of bone but that bone-mineral content,
as determined by a non-invasive means, does so within a 10 per cent error.
Clinical Relevance: This study demonstrates a high degree of positive
correlation between bone density and the security of screw fixation in the
human radius. Measuring bone density using a highly accurate, non-invasive,
safe technique has clinical relevance in preoperative assessment of
osteopathic patients who are being considered for internal fixation of the
radius with plates and screws.