A randomized trial to study the effect of different implant designs on knee function and joint kinematics after total knee arthroplasty

Total knee arthroplasty (TKA) is a cost beneficial surgery shown to improve pain, function and quality of life in patients with osteoarthritis. Despite the procedure´s general success, 20% of patients report postoperative pain and/or dissatisfaction With the surgical outcome. Through efforts to improve the procedure and clinical outcomes, debate has arisen regarding the role and management of the posterior cruciate ligament (PCL). The PCL is one of the primary stabilizers of the knee. It prevents the thighbone from sliding forward too far on the shinbone when the knee is bent. There are only two primary types of knee implants: one that retains the PCL (cruciate-retaining [CR]) and one where parts of the implant substitute for the PCL (posterior stabilized [PS] and anterior stabilized [AS]). In patients with an intact PCL, the decision about choosing a knee implant that retains the PCL or one where parts of the implant substitute for the PCL depends largely on the favour and training of the surgeon, and less on scientific evidence regarding the clinical outcomes Associated with each implant. To date, no studies have been performed determining whether there is a difference between these three designs with respect to either the patient’s perceived outcome or objective measures of knee function. There have been a limited number of studies conducted describing outcomes for two of the designs (CR and PS), but these studies are characterized by small numbers of patients, varying outcome measures, poor randomization and comparison of designs from different
manufacturers.

Aim of studies:
The aim of this study is to compare three prosthesis designs for TKA (CR, PS and
AS) and determine the best option for patients in need of knee replacement.