The purpose of this study is to compare the biologic properties of tendon to hone healing and hone to hone healing in knee ligament reconstruction. The lateral 4mm of patellar tendon which was detached from its tihial insertion site either subperiostcally(group I) or with a bone block(group II) was implanted and fixed using pullout method to the proximal tihia. Ten rabbits were killed at each of four time periods (two, four, eight and twelve weeks after the implantation), and the histological and biomechanical characteristics of thc graft healing sites were evaluated. Serial histological analysis of tendon to hone healing group revealed organization of the healing site similar to normal tendon to hone attachment by twelve weeks, while hone to bone healing group demonstrated direct hony union by eight weeks. The tension failure test for the patellapatellar tendon graft - tihia complex revealed that group II had significantly higher values than group I at four and eight weeks. The findings ot this study demonstrated that bone to hone healing has more rapid process than tendon to hone healing, although no significant difference was noted once the healing has matured. We can suggest lhat the duration and extent of postoperative protection of the knee for pntients who had a reconstruction of a ligament using hone - lendon autograft should be longer and higher than lor patients who had a reconstruction using hone - tendon hone autogralf.