The angle between the lower extremity force line and the position of the unicondylar prosthesis is an important factor affecting the long-term survival and rate clinical outcome of the unicondylar replacement prostheses. Insufficient lower limb alignment will accelerate the wear of prosthesis and reduce the survival rate of prosthesis. Excessive lower limb alignment will accelerate the progress of contralateral interventricular arthritis. It is generally believed that the lower limb force line should be corrected in mild varus after unicompartmental knee arthroplasty. However, some scholars believe that the lower limb alignment has no effect on the functional score and prosthesis survival rate after unicompartmental knee arthroplasty. The poor position of femoral and tibial prosthesis will cause unexplained pain and even prosthesis wear, but the optimal position of femoral and tibial prosthesis is controversial. It is generally believed that the posterior tibial slope should be corrected in the range of 3° to 7° in unicompartmental knee arthroplasty, but some scholars believe that excessive change of posterior tibial slope will also affect the balance of knee joint space and knee joint range of motion. This study shows that the correction of lower limb alignment to mild varus is still the best lower limb alignment for unicompartmental knee arthroplasty. The best position of femoral and tibial prosthesis needs to be confirmed by further biomechanical research. The correction of tposterior tibial slope should be changed according to the specific original dissection angle of patients before operation.
Keywords: Lower limb alignment; Prosthesis position; Unicompartmental arthroplasty.