Sliding of the compression hip screw in femoral neck fractures

Backing out of the compression screw in the sliding screw-plate hip osteosynthesis was analyzed in a series of 71 hips with medial femoral neck fractures during an observation period of 12-42 months, with a median of 26 months. In addition to the compression screw device, a parallel cranial lag screw was used. A postoperative primary diastasis in the fracture space of 1-5 mm in 11 cases did not predispose to major sliding of the screws or to healing problems. Thirteen of 27 fractures with late screw telescoping of 4 mm or more showed healing disturbances, 11 late segmental collapses, and 2 nonunions, compared with 7 disturbances, 6 late segmental collapses, and 1 nonunion among 39 cases with screw gliding of 3 mm or less. The difference was significant (p less than 0.05, Mann-Whitney). Five early mechanical failures were excluded from this analysis.