Advantages of cementless arthroplasty are preservation of bone stock. The most encouraging aspect of this series of total knee arthroplasties is the case of revisability in the components. Ortholoc Knee has the accuracy and reproducibility of bone
cutting with the effective intramedullary alignment system and the rigid fixation of tibial component by using screw and pegs. The patella component is inset-patella type.
From October 1990 to May 1993, the authors analyzed 50 patients, 82 cementless Ortholoc II and Ortholoc Modular total knee arthroplasty in csteoarthritis with an average 3 years 3 months (range 2 years to 4 years 6 months) follow up period. There were 35 cases in left side of knee, 47 cases in right side, 43 patients in female and 7 patients in male. The average age was 61.5 years09range 28 to 77 years). At the clinical analysis, preoperative average HSS knee rating score was 56.5 point (31 to 82 points). At the last follow up, HSS Knee rating score was 91.2 point (85 to 98 points). Preoperative average ROM was 108.7 degrees (70 to 120 degrees). At the last follow up ROM was 118.5 degrees (90 to 135 degrees). Preoperative flexion contracture was average 10.7 degrees (0 to 40 degrees). At the last follow up, flexion contracture was average 0.6 degree (0 to 10 degrees). For the radiographical analysis, American Knee Society Roentgenographic Evaaluation and Scoring System was used. The component position was as follow; average value of αangle was 93.8 degrees(89-100), βangle was 90.4 degrees(86-98) in anteroposterior view and γangle was 5.2 degrees(0-18), δangle was 90.4 degrees(83-98) in lateral view. In the plain AP view, preoperative average tibiofemoral shaft angle was vuarus 8.5 degrees (range varus 3 to 25 degrees). Postoperative average tibiofemoral shaft angle was corrected as valgus 6.5 degrees (range 4 to 10 degrees). Regarding the position of central stem to tibial shaft axis, 38 cases were found to be located in lateral side, 30 cases in medial side, and 14 cases in neutral side. Tilting angle of tibial tray to the perpendicular articular line of tibial shaft axis was average 1.7 degrees (range 1 to 4 degrees) in cases with valgus alignment of tibial components and -2.4 degrees 9range-1 to -5 degrees) in cases with varus alignment. The distance between axial lines of tibial component and tibial shaft was average 4.7㎜(range 1 to 6㎜) in valgus alignment, and
5.3㎜(range 1 to 7㎜) in varus alignment. There wass no loosening and wear. The clinical and radiological findings revealed no distince differences between these two implants. In summary, total knee replacement without using bone cement is a reliable and effective method of treating degenerative arthritic knee. The accuracy of bone cutting and the femoral and tibial entry points of intramedullary rod are very important for the correct insertion and alignment of prosthetic components.
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