Lesser posterior tibial slope angle ≤7⁰ (PTS-Angle) has negative effect on outcome of isolated PCL reconstruction: Comparative analysis of PTS ≤7⁰ vs > 7⁰ degrees.

Abstract

To determine incidence of posterior-tibial-slope (PTS) distribution in patients with isolated posterior-cruciate-ligament (PCL) tear, as-well-as the effect of PTS on radiological, clinical, and functional outcomes after PCL-reconstruction (PCL-R). 63 patients with symptomatic isolated PCL-tears who underwent PCL-R were divided into two groups based on a PTS-angle with a cut-off value of 7⁰-degrees: group-A (less than ≤7⁰-degree) and group-B (more than >7⁰-degree). All the patients were subjected to the same technique. The effect of PTS-angle on the radiological-outcome, (posterior-tibial-translation (PTT)) at 6-month and 1-year intervals was compared. Clinical-outcomes (knee range-of-motion (ROM), quadriceps-wasting (QW)), and functional outcomes (IKDC and Tegner-Lysholm scores) at 6-month, 1-year, and final follow-up was compared between the groups. PTS of less than ≤7⁰-degrees was seen in 66.7%. The mean-PTS-angle was 6.47 ± 2.40degrees. Radiologically, there was no statistical-difference in PTT at 6-months. However, at 1-year, PTT was less in group-A (3.98 ± 2.21 mm) than in group-B (3.03 ± 1.42 mm) (P = 0.04). Two patients in group-A had grade-III PTT at 6-months, and one of them had grade-III PTT at 1-year. At the mean-follow-up, group-A had lower IKDC and Tegner-Lysholm (81.55 ± 11.4, 90.19 ± 5.53) than group-B (86.56 ± 7.2, 94.6 ± 4.42), indicating a statistically significant difference (IKDC:P = 0.038, Tegner-Lysholm:P = 0.001). At 1-year and mean-follow-up, group-A had a significantly lower ROM(p = 0.047). There was no significant difference for QW at 6-months and 1-year. Lesser preoperative PTS angle (≤7⁰) has a negative effect on the outcome of isolated PCL-R and leads to secondaryposterior knee laxity than in patients with higher PTS angle (>7⁰). Incidence of lesser posterior tibial slope (≤7⁰)  in isolated PCL injuries is 66.7%.