Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length

Tibial bone tunnels were examined with bone scans 2 years after patella lig ament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tib ial tunnel was increased in 29% of patients. Marked increase of scintigraph ic uptake was associated with tibial tunnel enlargement of more than 35% an d a graft length in the tibial tunnel over 14 mm. Scan uptake was correlate d to tunnel enlargement (r=0,64, P<0.01) and tunnel enlargement was correla ted to graft length inside the tibial tunnel (r=0,59 P<0,001). No correlati on was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates th e enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation i s more than 14 mm below the joint.