Is it sufficient to reconstruct the superficial medial collateral ligament only in medial knee instability? A comparative study

Introduction The medial collateral ligament (MCL) is the primary static stabilizing structure on the medial aspect of the knee, contributing up to 78% of the restraining force to valgus loads. Sims and Jacobsen reported that 99% of medial injuries requiring operation had an associated injury to the posterior oblique ligament (POL), which was overlooked in many reports. Hypothesis Reconstruction of both superficial MCL and POL might be clinically advantageous in regaining valgus stability compared to superficial MCL reconstruction alone. Both groups were compared regarding the following parameters: clinical evaluation according to the Lysholm and the International Knee Documentation Committee rating scoring systems and stress valgus x-ray. Patients and methods Between January 2015 and April 2017, we conducted a prospective randomized analytical study, including 30 patients suffering from grade III MCL injury. They were divided into two groups (A) and (B). For group A, 15 patients underwent superficial MCL reconstruction only, while for group B, concomitant reconstruction of the superficial MCL and POLs. Results The mean Lysholm score in group A preoperatively was 37.9±8.1 and became 91.0±6.3 postoperatively with P value less than 0.001, while in group B, it was 38.7±11.4 and became 92.9±8.3 with P value less than 0.001. There was no statistical significant difference between both groups postoperatively (P=0.478). Regarding ligament examination of International Knee Documentation Committee score postoperatively, the frequency of cases of A, B, C, and D grades of Lachman in group A was 53.3, 40, 6.7, and 0%, respectively, versus 80, 20, and 0% in group B, and this difference was not statistically significant (P=0.4). According to valgus stress test, the frequency of cases of A, B, C, and D grades in group A was 66.7, 33.3, and 0%, respectively, versus 73.3, 26.7, and 0% in group B, and this difference was not statistically significant (P=0.7). The stress valgus x-ray evaluation of the degree of gapping in extension in group A was 1.7±0.5 versus 1.3±0.7 in group B and this difference was not statistically significant (P=0.1), and the degree of gapping in flexion in group A was 1.8±0.4 versus 1.4±0.7 in group B and this difference was not statistically significant (P=0.1). Conclusion There was no difference in the clinical and the radiological outcome between the reconstruction of the superficial MCL alone versus the concomitant reconstruction of the POL in patients with medial knee instability.