Reconstruction of Noncontained Proximal Tibial Defects with Divergent Screws and Cement

Abstract

Postoperative fracture is a well described complication following curettage and cementation of aggressive benign bone tumors. We asked whether: (1) the addition of diverging screws that engage the opposite cortex increase the strength and rigidity of the construct in the proximal tibia compared with (a) cement alone and (b) would cement with intramedullary Steinmann pins; and (2) the modes of failure be different for those constructs. The average load to failure for tibias reconstructed with cement augmented with diverging screws (6321 +/- 681 N) was higher than for tibias reconstructed with cement alone (2343 +/- 222 N). The average load to failure for tibias reconstructed with cement augmented with diverging screws (6885 +/- 445 N) was higher than for tibias reconstructed with cement and intramedullary Steinmann pins (5218 +/- 941 N). Furthermore, constructs with cement augmented with diverging screws were less likely to fail by an intraarticular fracture than other types of constructs. Our data support the use of diverging screws that engage the opposite cortex to augment the strength of the construct when using acrylic cement to fill noncontained defects after curettage of the proximal tibia. This more stable, stronger construct might allow earlier mobilization and rehabilitation after curettage, with a decreased risk of fracture.