THE KNEE-SOCIETY ROENTGENOGRAPHIC EVALUAT ION AND SCORING SYSTEM IN RADIOLOGICAL FOLLOW-UP OF TOTAL KNEE ARTHROPLASTICS

Purpose: To follow the radiographic parameters of prosthetic loosening of the Knee Society Roentgenographic Evaluation and Scoring System (K SRESS) and to test their clinical relevance. Methods: This prospective study documents the use of the KSRESS and clinical rating system in 3 33 primary posterior cruciate retaining PFC total knee arthroplasties preoperatively, at 3 month and at yearly intervals postoperatively. Th e average follow-up period was 3.2 years (range 2-5.5 y). Results: The average component position and alignment angles remained unchanged at biomechanically correct angles during the follow-up period. Radioluce nt lines were observed regularly at the edges of the tibial and femora l components. The average total radiolucent lines score decreased for the tibial component. Patellar and femoral lucencies remained unchange d. The total radiolucent lines scores did not correlate with postopera tive pain, body-mass-index, alignment, stability, knee and function sc ore. Four revisions, one with relevant radiolucent lines, had to be pe rformed. Conclusions: The KSRESS is a useful tool. Standardisation of roentgenograms is mandatory. The PFC arthroplasty, the operative techn ique and the instruments ensure a biomechanically correct implantation .