The influence of tibial resection on the joint gap and on stability against posterior laxity in posterior cruciate ligament-retaining total knee arthroplasty (CR-TKA) remains unclear. In addition, there are no detailed reports regarding how much of the tibial attachment of the posterior cruciate ligament (PCL) is preserved during tibial resection. Our goals were to evaluate the influence of tibial resection on the intraoperative joint gap and on postoperative anteroposterior stability in a clinical population, and to assess the preserved area of the tibial PCL attachment using cadaveric knees.
In 20 consecutive patients, the joint gaps before and after tibial resection at 90° flexion and full extension were analyzed during CR-TKA, and anteroposterior stability was evaluated postoperatively. In 11 cadaveric knees, tibial resection with a thickness of 8, 10, 12, or 14 mm and a posterior slope of 3, 4, 5, 6, or 7° was simulated using computed tomography images, and the percentage of the preserved area of the attachment was calculated.
The flexion gaps before and after tibial resection were 18.1 ± 1.9 mm and 18.4 ± 2.2 mm, respectively, with no statistically significant difference (p = 0.08). Similarly, the extension gap did not increase significantly before and after tibial resection (20.8 ± 2.5 mm and 21.0 ± 2.6 mm; p = 0.45). All knees maintained anteroposterior stability at the follow-up period (32.0 ± 1.9 months). The posterior slope of the tibial resection was 5.9 ± 1.4°, and the thickness of the lateral tibial resection was 10.4 ± 1.1 mm. The cutoffs to preserve more than 50% of the attachment were 10-mm thickness and 5° slope.
Our results showed that tibial resection did not influence the intraoperative joint gap or postoperative anteroposterior stability. However, our analysis demonstrated that increased amounts of tibial resection led to considerable damage to the attachment.