POSTERIOR CRUCIATE SUPPLEMENTING TOTAL KNEE REPLACEMENT USING CONFORMING INSERTS AND CRUCIATE RECESSION - EFFECT ON RANGE OF MOTION AND RADIOLUCENT LINES

This study was performed to determine if a sagittally curved conformin g tibial insert can be used with a retained, but balanced, posterior c ruciate ligament without deleterious effects on range of motion (ROM) and tibial radiolucencies, as compared with a flatter insert that is l ess conforming and does not require cruciate balancing. The authors re viewed 50 consecutive primary knees implanted with flatter posterior l ipped inserts and 50 consecutive primary knees with curved inserts and posterior cruciate ligament balancing. The average ROM for both group s was the same postoperatively as preoperatively: 111 degrees for the posterior lipped inserts and 113 degrees for the curved inserts. The i ncidence of tibial radiolucent lines was 8% for both groups. The autho rs conclude that sagittally curved, more conforming tibial inserts wit h retained, but balanced, posterior cruciate ligaments, do not adverse ly effect ROM and tibial radiolucencies. Their use forms an attractive compromise between the schools of cruciate preservation and cruciate substitution, maximizing their advantages while minimizing their disad vantages. Functional ROM can be achieved while bone stock is preserved , the joint line is restored, and wear characteristics are improved.