Background: The purpose of this study was to determine the effect of intraoperative coronal laxity in total knee arthroplasty on the postoperative condition.
Methods: We conducted stress arthrometric studies using a Telos arthrometer on 40 knees in 36 patients. Both posterior cruciate ligament-retaining (PCLR) prostheses and posterior cruciate-sacrificing (PCLS) prostheses were placed in 20 knees respectively. All of the TKA procedures were judged clinically successful (Hospital for Special Surgery scores: PCLR 92 +/- 3 points, PCLS 91 +/- 4 points). Laxities were measured under spinal anesthesia (immediately postoperatively) and 6 months postoperatively.
Results: PCLR prostheses had an average of 2.9 degrees +/- 1.8 degrees and 3.0 degrees +/- 1.2 degrees in abduction and 4.4 degrees +/- 2.8 degrees and 3.6 degrees +/- 1.5 degrees in adduction under anesthesia and the postoperative condition. PCLS prostheses had average laxities of 3.8 degrees +/- 1.4 degrees and 3.5 degrees +/- 0.9 degrees in abduction and 4.6 degrees +/- 3.8 degrees and 4.0 degrees +/- 1.7 degrees in adduction. There were no significant differences between them.
Conclusions: The findings suggest that surgeons should emphasize the achievement of suitable laxity under anesthesia to ensure the success of total knee arthroplasty.