70RADIOLOGICAL COMPARISON BETWEEN A TRADITIONAL AND A MODERN MONOMODULAR LUMBAR TOTAL DISC REPLACEMENT

Total disc replacement (TDR) is the gold standard for lumbar degenerative disc disease in selected patient groups. Traditional TDR designs benefit from a wealth of literature and use a polyethylene inlay pseudo-disc between two metal endplates. There is scarce literature for novel monomodular implants that form an artificial construct of woven annulus and central nucleus, providing physiological motion preservation.The aim was to compare the evolving changes to radiological position between monomodular and traditional implants and assess the relationship of migration with bone densitometry.This retrospective series of consecutive patients undergoing TDR under a single surgeon recorded demographics, co-morbidities, previous surgery and clinical outcomes. Measurements of endplate subsidence, lordosis and spondylolisthesis taken from weight-bearing erect x-rays at 0, 3, 6 and 12 months. Radiological outcomes were compared against CT bone densitometry.33 monomodular and 13 traditional implants. Mean age 40 ye...