Summary

We compared double-bundle PCL-reconstruction with single-bundle PCL-reconstruction, and the postoperative posterior stability was significantly better in DB PCL-R than in SB-R although there were no significant differences between the 2 procedures concerning the complications and the clinical evaluations.

Abstract

Introduction

Several studies have reported favorable results of PCL-reconstruction (R) using single-bundle (SB) techniques. However, the clinical results of this surgery have shown that mild residual laxity is common after this type of surgery. Recently, biomechanical studies have demonstrated that double-bundle (DB) PCL-R provides better stability than SB-R. We have also studied the utility of the hamstring tendon-‘hybrid’ autograft, which is composed of the multistrand tendon and polyester tapes. Based on these studies, we have developed a DB PCL-R procedure with hamstring ‘hybrid’ tendon autografts (KSSTA 2009). However, the superiority of SB or DB PCL-R remains uncertain. We hypothesized that the DB procedure may be significantly better concerning the posterior laxity than the SB procedure, while there may be no significant differences in the Lysholm knee score, and the International Knee Documentation Committee (IKDC) evaluation between the 2 procedures. The purpose of this study was to test this hypothesis.

Methods

A retrospective, comparative study was conducted with 35 patients (35 knees) who underwent PCL-R using hamstring-hybrid tendon autografts between 2003 and 2016. There were 34 men and 1 woman with a mean age of 32 (14–56) years at the time of surgery. ten cases required isolated PCL-R, and the others had the following additional ligament reconstruction associated with PCL-R according to our previous reported techniques (Arthroscopy 2004, KSSTA 2008, AJSM 2013); 20 cases required ACL-R using the semitendinosus (Semi-T) and/or gracilis (G) tendons, 10 cases required medial collateral ligament (MCL)-R using the Semi-T, and 6 cases required posterolateral corner (PLC)-R using the biceps tendon. All patients were divided into the two groups; SB PCL-R (Group S: 10 knees) and DB PCL-R (Group D: 25 knees). Two years after surgery, each patient was examined with the standard clinical evaluations method. This study design had been accepted by the institutional review board clearance in our hospital. The surgical procedure for Group S, anterolateral (AL) bundle-R was performed with the outside-in technique. In Group D, AL and posteromedial (PM) bundle-R were performed. Statistical analysis was made using Mann-Whitney’s U-test. The significance level was set at p=0.05.

Results

There were no statistical differences in background factors between the 2 groups. No patients showed a loss of knee extension more than 5° and a loss of flexion more than 15°.The side-to-side differences in anterior-posterior translation (KT-2000) at 70° showed no significant difference between the two groups (2.3 mm and 1.6 mm in Groups S and D, respectively). Stress radiograph at 90° showed that Group D (53 %) was significantly less (p=0.009) in the posterior translation than Group S (45 %). The Lysholm score averaged 87 and 90 points in Groups S and D, respectively. The IKDC evaluation showed that 60% and 64% of cases in Groups S and D, respectively, were evaluated as ranks A and B. There were no significant differences in the other clinical evaluations between the 2 procedures.

Discussion

The postoperative posterior stability was significantly better in DB PCL-R than in SB-R, although there were no significant differences between the 2 procedures concerning the other clinical evaluations. Recent meta-analysis reported that DB PCL-R provided significantly improved objective posterior tibial stability and objective IKDC scores when compared with SB PCL-R in randomized clinical trials (Arthroscopy 2017). However, further long-term studies are needed to assess the subjective and objective patient outcomes of DB procedure in patients with the PCL-deficient knee.