Osteocutaneous radial forearm free flaps - The necessity of internal fixation of the donor-site defect to prevent pathological fracture

Background Osteocutaneous radial forearm free flaps have fallen from favor due to pathological fractures of the radius. The purposes of this study were to propose a means to decrease the rate of pathological fracture by prophylactic fixation of the donor-site defect and to evaluate this technique biomechanically, Methods: Two groups of ten matched pairs of fresh-frozen cadaveric radii were harvested. In Group 1, an eight-centimeter length of radius comprising 50 percent of the cross-sectional area of the bone was removed to simulate an osteocutaneous radial forearm donor-site defect. This defect was created in one member of each pair, with the other bone in the pair left intact. In Group 2, both members of the ten matched pairs of radii had identical defects created as previously described, However, one radius in each pair had a twelve-hole, 3,5-millimeter dynamic compression plate placed across the segmental defect. In each group, five matched pairs were tested to failure in torsion and five matched pairs were tested to failure in four-point bending. Results: In Group 1, the intact radius was a mean of 5.7 times stronger in torsion and 4.2 times stronger in four-point bending than the radius with the segmental resection, In Group 2, the radius that was ostectomized and fixed with a plate was a mean of 4.0 times stronger in torsion and 2.7 times stronger in four-point bending than the ostectomized radius. Conclusions: Removal of an eight-centimeter segment from the radius dramatically decreased both torsion and bending strength, Application of a plate over the defect in the radius significantly restored the strength of the radius (p = 0.01). Clinical Relevance: The segmental defect created in the radius when an osteocutaneous radial forearm free flap is harvested weakens the donor bone an unacceptable amount, resulting in a high risk of pathological fracture, We believe that prophylactic internal fixation of the donor-site defect with a plate restores strength to such a level that pathological fracture may be prevented, thus increasing the utility of the osteocutaneous radial forearm free flap.