Abstract
INTRODUCTION
Normal kinematics have not been achieved in TKA design. Recently, knee simulation studies have suggested that a medial pivot TKA can achieve the anatomic pathway that reduce mid-flextion rollback and increase lateral rotation. However, the influence of postoperative flextion angle associated with medial tightness for guide motion TKA remains poorly understood. The purpose of this study was to investigate the effect of postoperative flextion angle and clinical outcomes associated with tightness for medial component gap (MCP).
METHODS
We evaluated 79 patients who underwent 84 medial pivot The Journey.2. Bi-Cruciate Substituting (BCS) TKA using the measured resection tequnique, from June 2014 to March 2016. We measured the gaps after implantation from extension to full flextion with reduced patella by constant distraction force (120N). A new tensor has the same articular shapes as that the tibial liner, including anterior and posterior structure.
RESULTS
There were no patients with midflextion instability for varus ligament balance. Postoperative knee flextion angle was positively corrected with preoperative knee flextion angle (r=0.62, p=0.001). The MCP difference (max-mini)(r=0.66, p=0.002) and Lateral minus medial component gap (varus angle) (r=0.43, p=0.001)from extension to full flextion was negative correlations with postoperative flextion angle.
DISCUSSION AND CONCLUSIONS
Medial tightness and no lateral laxity as well as joint component gap at extension throughout full flex is the most important factors affecting postoperative flextion angle in guided motion TKA.
