Posterior laxity increases over time after PCL reconstruction

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA Vol. 27; no. 2; pp. 389 - 396
• Main Authors: Gwinner, Clemens, Jung, Tobias M., Schatka, Imke, Weiler, Andreas
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2019; John Wiley & Sons, Inc
• Subjects: Body mass; Flattening; Kinematics; Knee; Ligaments; Medical personnel; Medicine; Medicine & Public Health; Orthopedics; Patients; Radiographs; Radiography; Restoration; Surgeons; Surgery; Translation; Tibial slope; Posterior tibial translation; Posterior cruciate ligament; Timely increment; Ligament reconstruction
• ISSN: 0942-2056; 1433-7347; 1433-7347
• DOI: 10.1007/s00167-018-5035-y

Purpose Restoration of posterior tibial translation (PTT) after reconstruction of the posterior cruciate ligament (PCL) is deemed necessary to restore physiological knee kinematics. However, current surgical techniques have failed to show a complete reduction of posterior laxity. It was hypothesized that early postoperative PTT increases over time. Methods The study comprised of 46 patients (10 female, 36 male; 30 ± 9 years), who underwent PCL reconstruction in a single-surgeon series. Patients were evaluated by bilateral stress radiographs in a prospective manner preoperatively; at 3, 6, 12 and 24 months; and at a final follow-up (FFU) of at least 5 years. Covariants included age, gender, BMI, tibial slope (TS) and the number of operated ligaments. Two blinded observers reviewed all radiographs, evaluating the TS and the posterior tibial translation. Results All patients were evaluated at a mean final follow-up of 102 (range 65–187) months. Mean side-to-side difference of the PTT significantly improved from preoperative to 3-month postoperative values (10.9 ± 3.1 vs. 3.6 ± 3.8 mm; P  < 0.0001). The PTT increased to 4.6 ± 3.7 mm at 6 months, to 4.8 ± 3.3 mm at 12 months, to 4.8 ± 3.2 mm at 24 months, to 5.4 ± 3.4 mm at FFU. Consequently, there was a significant increase of PTT between 3-month and final follow-up (3.6 ± 3.8 vs. 5.4 ± 3.4 mm; P  = 0.02). Flattening of the TS resulted in a significantly higher PTT compared to subjects with a high TS at 24 months and FFU. There was no significant influence by BMI, age, gender and the number of operated ligaments. Conclusions Early results after PCL reconstruction seem promising as posterior tibial translation is significantly improved. However, there is a significant increase in PTT from early postoperative values to the final follow-up of at least 5 years. This is particularly notable in patients with flattening of the TS. As a consequence, surgeons and patients need to be aware that initial posterior stability should not be equated with the final outcome. Level of evidence Cohort study, Level III.