Background: Knee arthroplasty has been traditionally based on mechanical alignment restoration. In the newer, “Kinematically aligned knee replacement”, the eroded bone and joint surfaces in addition to saw-blade thickness are removed and replaced by the components. This study compared the results of two techniques of knee arthroplasty.

Methods: In a clinical trial study, 90 patients who were candidates for knee arthroplasty were divided into 2 groups: 45 cases received knee arthroplasty by “mechanically aligned” and 45 by “Kinematically aligned” technique. The two groups were compared after 1 year by Lysholm score, hospitalization period, subjective satisfaction, and period of need for ambulatory aid.

Results: 73 patients referred for follow up: 37 patients in the kinematic and 36 in the mechanical group. The mean hemoglobin drop was not significantly different between the two kinematic and mechanical groups; while the post operation mean hemoglobin drop difference was significant (p < /em>=.001). No significant difference in the patient satisfaction of the operation was observed between two groups. The difference of mean Lyshlom score was different between two groups (p < /em>=.000).

Conclusions: kinematically aligned” knee replacement is associated with less pain, earlier return to daily activity, lesser intra operative bleeding and more patient satisfaction.