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 ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r=0,64, P<0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r=0,59 P<0,001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the 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 is more than 14 mm below the joint.