To compare and analyze length change of patella tendon after intramedullary nailing of tibial shaft fracture using transtendinous approach.

Thirty-two cases were analyzed from December, 1999 to December, 2005. Insall Salvati ratios were estimated. Severity of initial trauma, duration of nail retension, knee function and pain on change of length of patellar tendon was evaluated.

Mean duration of nail retention was twenty-two months. The shortening of patella tendon was observed in 25 cases (p<0.001). The effect of AO type and the duration of nail retension on the decrease of Insall Salvati ratio was not significant (p>0.05, p=0.778). Lysholom score decrease to 89.5. There was no significant difference between the shortening of patellar tendon length and knee pain (p=0.058).

After intramedullary nailing for closed tibia fracture, shortening of patellar tendon length is observed. That is irrelevant to the fracture type and the duration of nail retension. The shortening of patella tendon length may contribute to decreasing of knee function, but it was no significance of knee pain after intramedullary nailing.