The Change of the Coronal Joint Line Level after PCL preserving and substituting Total Knee Arthroplasty

ABSTRACT

PURPOSE: The change of the joint line is associated not only with bone cutting levels but also balance of soft tissue. The main objective of this study analyze to compare the changes of the coronal joint line levels between PCL retaining total knee arthroplasty and PCL-substituting total knee arthroplasty, using the new method designed by authors. MATERIAL AND METHODS: A total 44 knees of 22 patients who received both TKA, of whom the one side was CR TKA and the other side was PS TKA, were analysed on pre- and post-operative weight-bearing anteroposterior radiopraphy of the knee. The joint line levels were measured two times by one author and one time by different author. RESULTS: The proximal shift of the joint line showed differently in both groups. The average of shifting values were 2.4+/-4.1 mm in CR TKAs, and 5.4+/-5.8 mm in PS TKAs. PS TKAs had significantly larger shifting value than CR TKAs for all times(p<0.05). CONCLUSION: The results of this study showed that the joint line level proximally shifted after TKA, using measured resection technique and gap technique. The shifting level in PS TKA was larger than CR TKA. But it is difficult to predict the change of joint line level after TKA, because of deviation between case by case and the standard deviation of the measured value was 4~6 mm.