Assessment of posterior stability in total knee re

Authors: S Louisia R Siebold J Canty R J Bartlett

Publish Date: 2005/04/02

Volume: 13, Issue: 6, Pages: 476-482

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Abstract

The aim of this study was to assess the posterior stability of two different designs of total knee replacement TKR with deepdished mobile bearing MB implants using stress Xrays In a prospective nonrandomized consecutive study 34 patients with primary osteoarthritis of the knee underwent TKR In group A 17 knees they received a MB insert with a Duracon prosthesis and in group B 18 knees a Genesis prosthesis In all cases the posterior cruciate ligament PCL was resected All patients had pre and postoperative kneeling Xrays and were clinically evaluated with the Knee Society Score Measurements on the radiographs were taken by tracing a line along the posterior cortex of the tibia and then measuring the perpendicular distance to a point marked at the posterior corner of Blumensaat’s line The average follow up was 107 months for group A and 54 months for group B No statistical difference could be found in terms of clinical results and pre and postoperative kneeling Xrays between the two groups In each group all knees demonstrated a significant posterior tibial translation postoperatively compare to their preoperative status p00001 There are advantages in resecting the PCL in TKR mobile flexion gap correction of fixed deformity more flexibility to adjust the joint line The use of a deep dished polyethylene PE insert provides stability and use of MB insert reduces PE wear whilst retaining congruity Two designs of deepdished MB inserts showed significant posterior tibial translation on stress Xrays It remains to be determined what amount of laxity is optimal for clinical function and polyethylene longevity

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