Is weight-bearing as tolerated safe after proximal tibial metaphyseal autogenous bone harvest? A systematic review and meta-analysis.

Evidence was reviewed to assess the decrease in compressive strength postoperatively. The PRISMA guidelines were followed. PubMed, Embase, Web of Science, Google Scholar, and ProQuest were searched. Five cadaver studies met the inclusion criteria (49 cadavers). Three reported force leading to fracture (FLF), which ranged between 1034 N and 9962 N consistently higher than three times cadaver body weight. Only one reported statistically significant lower FLF in decancellated tibias compared to the contralateral tibias (mean 3766.9 N vs 5126.4; stability reduction 26.5%). The overall estimate of FLF in decancellated tibias was 4321.6 N (95% confidence interval 3434.4-5208.8 N. Meta-analysis estimated a significant difference in force leading to fracture (ΔFLF) 1098.1 N, 95% confidence interval 547.8-1648.5 N. While mean FLF in all studies and the pooled data was above a force three times the body weight of an average adult (70 kg x 3 = 2100 N), three cadavers showed FLF values below this threshold. Increasing the threshold to 2400 N (roughly relating to a body weight of 80 kg, increased this number to six. Normal weight-bearing after decancellation seems to be statistically safe. Clinically, however, the authors are not able to generalize this assumption.