Summary

This paper compared anatomic versus non-anatomic-posterolateral-corner (PLC) reconstructions with autografts for grade 3 posterolateral corner knee lesions combined with single bundle posterior cruciate ligament (PCL) reconstruction resulting in superior stability favoring anatomic reconstruction.

Abstract

Introduction

There is a lack of consensus regarding if the anatomic PLC reconstructions are better than non-anatomic ones with some studies presenting similar results and some presenting superior results favoring anatomic PLC reconstructions. As the anatomic reconstructions reproduce the three main PLC structures and its footprints, theoretically, it should lead to better outcomes specially in the setting of high grade PLC lesions (Hughston grade III or Fanelli grade C) or combined posterior cruciate ligament (PCL) lesions as both the PFL and the PT are secondary restraints to tibial posterior translation
This is the first clinical study to compare anatomic PLC reconstructions versus non-anatomic in only high-grade PLC injuries (Hughston grade III or Fanelli grade C) combined to PCL lesions.
Our hypothesis was that, combined with single bundle PCL reconstruction, an anatomic PLC reconstruction would lead to better results than a non-anatomic PLC reconstruction.
OBJECTIVES
To compare anatomic versus non-anatomic-posterolateral-corner(PLC) reconstructions with autografts for grade 3 posterolateral corner knee lesions combined with single bundle posterior cruciate ligament(PCL) reconstruction.

Methods

An outcome comparative study of chronic PCL lesions submitted to single bundle PCL reconstruction combined with a grade 3 PLC injury from Hughston and Fanelli classifications treated either by anatomic or non-anatomic PLC-reconstruction with autografts with at least 24 months of follow-up. Outcomes: Lysholm, IKDC, Tegner, side-to-side-difference(SSD) from posterior and varus stress radiographs, IKDC objective scores for posterior drawer, varus stress, dial test and recurvatum. Student’s t- and two-proportion Z-test were used. Power for sample size was 88.2%.

Results

39 (thirty-nine patients were evaluated: 18 in the Anatomic-PLC-group and 21 in the Non-anatomic-PLC-group. Mean follow-up: 28.3months (range 24 to 59months). Preoperatively, no significant differences were observed between the two groups in terms of age; time from injury until surgery; Lysholm; subjective IKDC; posterior, varus, external rotation or recurvatum laxity; stress radiographs; incidence of associated ligament and meniscus injuries. Postoperatively, no significant differences were observed for Lysholm (p=0.189), subjective IKDC (p=0.261), Tegner (p=0.385), mean improvement in Lysholm and IKDC scores (p=0.144, p=0.354, respectively), posterior tibial translation on stress radiographs [postoperative SSD (p=0.205) and percentage of patients with unacceptable (≥8mm) asymmetry (p=0.912)]; complications. Significant differences favoring Anatomic-PLC-group were observed for Posterior-Drawer-Test (0.83±0.51 vs 1.1±0.43,p=0.046); Varus-Stress-Gapping at 30o (0.5±0.78 vs 1.14±0.85, p=0.01); Tibial-External-Rotation both 30o (33.3% vs 80.9%, p=0.002) and 90o (16.6% vs 47.6%, p=0.041); Asymmetrical-Recurvatum (5.5% vs 47.6%, p=0.00362); SSD-Lateral-Gapping-Varus-Stress-Radiographs (1.8±2.1 vs 3.35±2.28, p=0.028). Failure (presence of any of the following: Posterior Drawer≥2+, Varus Stress≥2+, SSD≥8mm on Posterior-Radiograph or ≥4mm on Varus-Stress-Radiograph): 5% Anatomic versus 19% Non-anatomic, no statistical difference, p=0.103.

Conclusion

Anatomic posterolateral corner reconstruction with autografts provided superior stability compared to non-anatomic reconstruction in the sertting of combined grade 3 posterolateral corner injuries and single bundle posterior cruciate ligament reconstruction.

Study design: Cohort study; Level of evidence 3.

Keywords: posterolateral corner, anatomic reconstruction, posterior cruciate ligament