Posterior femoral translation in medial pivot total knee arthroplasty of posterior cruciate ligament retaining type.

PURPOSE

To report clinical results and demonstrate posterior femoral translation (PFT) in medial pivot total knee arthroplasty (TKA) of posterior cruciate ligament (PCL) retaining type.

MATERIALS AND METHODS

A prospective study was performed upon thirty consecutive subjects who were operated on with medial pivot TKA of PCL retaining type between March 2009 and March 2010 and had been followed up for at least 2 years. Clinically, the knee society knee score and function score were used. In full extension and active flexion lateral radiograph, anteroposterior (AP) condylar position and magnitude of PFT was determined.

RESULTS

At last follow-up, the mean knee society knee score and function score improved significantly compared to preoperative scores. The AP condylar positions were consistently posterior to midline throughout the entire range of flexion. The PFTs averaged 0.31 (±0.12) of half length of tibial base plate and were greater in higher flexion cases (r = 0.56, p = 0.0012). There were no cases having either component migration or radiolucent line wider than 2 mm except for one case showing instability related to trauma.

CONCLUSIONS

In medial pivot TKA of PCL retaining type, clinical outcomes were satisfactory and posterior femoral translations were consistently observed during progressive flexions of knees at two- to three-year follow-up.