MRI of the knee after locked unreamed intramedullary nailing of tibia.

We analysed the reason for knee pain after intramedullary (IM) nailing with standard MRI sequences at a mean of 27 months (range 2-45) after nail removal in eleven patients with a mean age of 30 years (range 15-52). Knee pain was assessed in four grades. All our patients had signal changes of fluid in the nail channel, areas of low signal intensity in Hoffa's fat pad and subcutaneous low signal nodes in front of a thickened patellar ligament. Ten patients had low signal adhesions from the nail insertion towards the patellar ligament. Six patients had severe knee pain and even marked adhesions. Two patients had no knee pain; one of these two had minimal adhesions and the other one no adhesions. Five of the patients had a meniscal tear and/or local cartilage reduction. The degree of adhesions from the nail insertion in the tibia towards the patellar ligament was proportional to the degree of knee pain. No sign of acute inflammation was found.