Sequential Changes in Posterior Tibial Translation After Posterior Cruciate Ligament Reconstruction: Risk Factors for Residual Posterior Sagging

Abstract

Background: Residual posterior sagging may occur after posterior cruciate ligament (PCL) reconstruction (PCLR), yet when it mainly occurs is not fully understood. Purpose: To elucidate sequential changes in radiographic posterior tibial translation (PTT) after PCLR. Study Design: Case-control study; Level of evidence, 3. Methods: The authors retrospectively investigated the radiographic findings from 22 patients who underwent bisocket double-bundle PCLR for isolated PCL injury with at least 2 years of follow-up (mean, 4.5 years; range, 2-10 years). Injury severity was assessed using PTT on lateral radiographs with gravity sag views and was stratified according to side-to-side difference in the tibial-femoral stepoff: grade 1 (<5 mm), grade 2 (5 to <10 mm), or grade 3 (≥10 mm). Measurements were taken preoperatively and then immediately, 3 months, 6 months, 1 year, and ≥2 years postoperatively. The authors also investigated the risk factors for residual posterior sagging, indicated when PTT was ≥5 mm (grade ≥2) at the minimum 2-year follow-up. Results: Preoperatively, 13 patients had a grade 2 injury, and 9 had grade 3 injury. The PTT, restored immediately after PCLR, significantly increased at 3 months ( P < .001) but remained unchanged thereafter ≥2 years. There were 7 cases of postoperative PTT ≥5 mm on radiographs. Patients with residual posterior sagging had significantly larger mean PTT than did those without residual posterior sagging at all time points except for immediately postoperatively (preoperatively, 9.1 ± 1.6 vs 12.2 ± 2.3 mm; 3-month follow-up, 2.7 ± 1.6 vs 7.0 ± 1.8 mm; ≥2-year follow-up, 3.4 ± 1.0 vs 6.5 ± 1.4 mm; P < .001 for all). Multivariate logistic regression analysis showed that preoperative grade 3 injury was independently associated with residual posterior sagging (OR, 26.809; 95% CI, 1.257-571.963; P < .001). Conclusion: The initially reduced postoperative PTT significantly increased within 3 months using conventional rehabilitation protocols, but no progression was observed up to 4.5 years after PCLR. Preoperative grade 3 injury was independently associated with residual posterior sagging.

Small size anterolateral bundle graft and decreased posterior slope angle of tibia are the risk factors associate with postoperative posterior tibial translation after double-bundle posterior cruciate ligament reconstruction

“…Third, the minimum follow-up period was 12 months after surgery. However, sequential change in PTT after surgery was con rmed in 3 months, and there was no signi cantly development between 3, 6, 12, and 24 moths has been reported 11 . Fourth, the details of the mechanisms and timing of posterior laxity after surgery were obscure.…”

“…Some studies reported that levels of side-to-side PTT after double-bundle PCL reconstruction measured by an arthrometer or radiographs were 2.4 mm to 3.9 mm, or 4 mm to 5 mm more than the native knee 4,10 . Residual posterior sagging was already occurred after 3 months postoperatively was also reported 11 . Tachibana et al also introduced that preoperative grade 3 injury was independently associated with residual posterior sugging 11 .…”

“…Residual posterior sagging was already occurred after 3 months postoperatively was also reported 11 . Tachibana et al also introduced that preoperative grade 3 injury was independently associated with residual posterior sugging 11 . However, the risk factors for postsurgical PTT after PCL reconstruction have not been fully elucidated.…”

“…Previously, preoperative grade 3 injury was the optimal risk factor associated with postoperative PTT has been reported 11 . It was possible that preoperative grade 3 injury induces other soft tissue laxity such as articular capsule.…”

“…Other potential risk factors were analysed with Spearman's rank correlation coe cient and the Mann Whitney U-test. Multivariate logistic regression analyses were performed to identify signi cant risk factors according to Tachibana et al 11 and odds ratios (ORs) and 95% con dence intervals (CIs) were calculated. Receiver operating characteristic (ROC) curve analysis was performed to identify the optimal cutoff value for postoperative PTT between subgroups.…”