Stability of subchondral bone defect reconstruction at distal femur: comparison between polymethylmethacrylate alone and steinmann pin reinforcement of polymethylmethacrylate.

Polymethylmethacrylate (PMMA) is often used to fill the large subchondral defects following intralesional curettage of a giant cell tumor of the bone. Many authors have reported the use of Steinmann pins to reinforce the bone cement. However, whether this is of real benefit in improving the stability of the defect is controversial. Thirteen matched pairs of cadaveric distal femurs were obtained and tested in uni-axial compression to determine the strength of this reconstruction. The strength of normal distal femurs was compared with the strength of defective femurs using 5 matched pairs of cadaveric distal femurs. A significant difference between the two groups was demonstrated in the failure load, stiffness, yield point and total energy absorbed to failure (p < 0.05). The second part consisted of eight matched pairs of specimens filled with PMMA alone versus PMMA with Steinmann pin reinforcement. There was no significant difference in failure load, stiffness, yield point and total energy absorbed to failure (p > 0.05). The addition of Steinmann pins did not significantly improve the strength of the subchondral defect reconstruction in uni-axial compression compared with PMMA reconstruction alone.