Abstract
The mobile bearing knee system has been designed to combine high stability and kinetic function with or without the posterior cruciate ligament. In this kontext the MBK-system is mainly qualified for patients with sufficient kollateral ligaments. Regarding to the origin anatomy a special attachment of the articulating surface allows an anterior-posterior movement of 4,5 mm and a rotation of 53 degrees. The sagital scape of the femoral component guarantees concruency to the articulating surface throughout a range of motion from 5 degress extension to 105 degress flexion. According to this fact high stresses to polyethylene with the consequence of an increase of attrition could be reduced.
From May 1997 to June 2001 236 mobile bearing knees were implanted in 220 patients. In June 2000 100 patients with 1 to 2 year follow up were investigated clinically and radiologically. The Knee Society Score was used for the clinical assessment. By using a special study questionaire pre-, intra- and postoperative data were collected.
Overall results in the first cases with 1 to 2 year follow up were good to excellent. Over 90% of the whole study group represented a plain increase of score values pre- to postoperatively. Regarding to the first 100 implantations postoperative complications were seen in 3 cases (1 deep vein thrombosis, 1 fixed flexion deformity, 1 sub-luxation of the patella). Intraoperative complications were noticed by one patient because of an uncomplicated tibial fissure. One re-admission was necessary in 1 case because of a traumatic patella fracture. A reduction of pain was noticed in 89,2% after 1 year, in 100% after 2 years. In case of the radiological follow up no signs of loosening or implant failure were seen.
Till June 2001 we had 2 more complications. One TKR has been revisised because of infection. One tibial component was changed because of instability and malrotation.
The first results in 100 cemented mobile bearing knees were very encouraging. All patients with 1 to 2 year follw up represented good clinical and radiological results. Mechanical implant failures were not seen in any cases.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
