Does harvesting the medial third of the patellar tendon cause lateral shift of the patella after ACL reconstruction?


Published online: Aug 27 2003

Dhillon MS, Mohan P, Nagi ON.

Department of Orthopaedics, Post Graduate Institute of Medical Education & Research, Chandigarh, India

Abstract

Many centers do not use the medial third of the patellar tendon as a graft for ACL reconstruction due to the apprehension that there may be post harvest maltracking of the patella towards the lateral side. We undertook a prospective study to evaluate patellar alignment in 30 patients in whom ACL reconstruction was done using the medial third of the patellar tendon. Q-angle assessment was the rough clinical parameter, and the Merchant view, Laurin views, and CT scans were used for radiological assessment. The assessment was done preoperatively and at six months post surgery, and the contralateral normal knees were used as controls. We observed no significant changes in the congruence angle (pre-op -13.86 degrees, postop -12 degrees) or the lateral patellofemoral angles in the pre-operative and postoperative knees as compared to the controls. CT scans were more sensitive for evaluating the congruence angles, and picked up an insignificant abnormal lateralisation of the patella in four cases. None of these patients however had any postoperative symptoms of misalignment. Although medial third graft harvesting did have a 13% change in patellar alignment, this was not statistically significant. Post harvesting local problems are inherent to the procedure, and are independent of the site of harvesting, as they were also seen in cases with no evidence of misalignment.