The Effect of Allograft Meniscal Replacement on Intraarticular Contact Area and Pressures in the Human Knee: A Biomechanical Study

Abstract

To define the biomechanical effects of total lateral meniscectomy and of subsequent lateral meniscal al lograft replacement on load transmission and distribu tion across the human knee, we mounted 10 fresh- frozen, young human cadaveric knees on a mechanical testing system. Peak pressure and contact area profiles were determined at 0°, 30°, and 60° of knee flexion using pressure-sensitive film and a den sitometer. Load transmission profiles were determined for each knee in a sequential test order: 1)intact knee, 2) after lateral meniscectomy, 3) after implantation of size-matched meniscal allograft fixed with bone plugs, and 4) after release of the anterior and posterior horn attachments of the allograft. Total lateral meniscec tomy resulted in a 45% to 50% decrease in total con tact area. Allograft replacement increased total contact area by 42% to 65% as compared with total meniscec tomy at all flexion angles. After release of the anterior and posterior horn attachments, contact area was identical to that after total meniscectomy. Total lateral meniscectomy resulted in a 235% to 335% increase in peak local contact pressure. Allograft replacement de creased these pressures by 55% to 65% at all flexion angles, but they remained significantly greater than those in the intact state. After release of the anterior and posterior horn attachments, contact pressures were identical to those after total meniscectomy. Com pared with total meniscectomy, meniscal allograft transplantation significantly increases contact area and decreases peak local contact pressures, but any bio mechanical advantages are lost without bone plug fix ation of the anterior and posterior horns.