Medial Pivot in Total Knee Arthroplasty: Literature Review and Our First Experience.

Abstract

Background: Traditional total knee implants designs, usually, are not able to reproduce the physiological kinematics of the knee, leaving almost 20% of the patients, those who underwent a total knee arthroplasty (TKA), not fully satisfied. Modern inserts are nowadays designed with a fully congruent medial compartment to reproduce the normal medial pivoting biomechanics of the knee. The aim of this article was to evaluate preliminary clinical improvement using the Medial Congruent (MC) insert as specific level of constraint.

Materials and methods: A total of 10 consecutive patients have been enrolled in this study and treated using an MC tibial polyethylene insert. The Oxford Knee Score (OKS) and the Knee Society Score (KSS) have been assessed preoperatively and at 3-month, 6-month, and 1-year follow-up (FU) and used as validated measurements to evaluate early clinical improvements. Postoperative radiological examination was reviewed looking for radiolucent lines or loosening of the components.

Results: Average improvement in OKS was from 19.5 to 41.2, whereas KSS improved with an average score from 64.7 preoperatively to 167.5 at the final FU showing good to excellent results in 95% of the treated knees. Evaluating the range of motion, the average maximum active movement was 124° and none of the patients needing for a revision surgery or manipulation under anesthesia. No complications were observed at the final FU as septic or aseptic loosening or vascular or neurologic injury.

Discussion and conclusions: Medial Congruent insert showed good to excellent clinical results at 1-year FU. Range of motion and subjective outcomes were satisfying and comparable with results obtained in literature using traditional TKA design.