THE USE OF ONE COMPARED WITH 2 DISTAL SCREWS IN THE TREATMENT OF FEMORAL-SHAFT FRACTURES WITH INTERLOCKING INTRAMEDULLARY NAILING - A CLINICAL AND BIOMECHANICAL ANALYSIS

The torsional and compressive biomechanical characteristics of a syste m for intramedullary fixation with a slotted locking nail and either o ne or two distal locking screws were evaluated in sixteen femora obtai ned from eight cadavera. No significant difference was found in the to rsional rigidity or axial load to failure when one as opposed to two d istal screws had been used. We also managed twenty-seven patients who had a fracture of the femoral shaft with interlocking fixation, using only a single distal screw for distal fixation. The average duration o f follow-up was nine months (range, three to twenty-five months). The average time to radiographic healing was three months (range, two to s ix and one-half months). There were no non-unions or failures of the i mplant. Clinically unimportant migration of the distal screw occurred in rive patients. We concluded that one distal screw provides adequate distal fixation of fractures of the femoral shaft treated with interl ocking intramedullary nailing.