THE EFFECT OF ALLOGRAFT MENISCAL REPLACEMENT ON INTRAARTICULAR CONTACT AREA AND PRESSURES IN THE HUMAN KNEE - A BIOMECHANICAL STUDY

To define the biomechanical effects of total lateral meniscectomy and of subsequent lateral meniscal allograft replacement on load transmiss ion and distribution across the human knee, we mounted 10 fresh-frozen , young human cadaveric knees on a mechanical testing system, Peak pre ssure and contact area profiles were determined at 0 degrees, 30 degre es, and 60 degrees of knee flexion using pressure-sensitive film and a densitometer. Load transmission profiles were determined for each kne e in a sequential test order: 1)intact knee, 2) after lateral meniscec tomy, 3) after implantation of size-matched meniscal allograft fixed w ith bone plugs, and 4) after release of the anterior and posterior hor n attachments of the allograft. Total lateral meniscectomy resulted in a 45% to 50% decrease in total contact area. Allograft replacement in creased total contact area by 42% to 65% as compared with total menisc ectomy at all flexion angles. After release of the anterior and poster ior horn attachments, contact area was identical to that after total m eniscectomy. Total lateral meniscectomy resulted in a 235% to 335% inc rease in peak local contact pressure. Allograft replacement decreased these pressures by 55% to 65% at all flexion angles, but they remained significantly greater than those in the intact state. After release o f the anterior and posterior horn attachments, contact pressures were identical to those after total meniscectomy. Compared with total menis cectomy, meniscal allograft transplantation significantly increases co ntact area and decreases peak local contact pressures, but any biomech anical advantages are lost without bone plug fixation of the anterior and posterior horns.