Augmented suture pull-out with suture-button (triple fixation) yields less radiological residual laxity than suture pull-out technique alone-for arthroscopic reduction and internal fixation (ARIF) of posterior cruciate ligament avulsion fractures.

Abstract

Objectives: Among numerous arthroscopic reduction and internal fixation (ARIF) techniques for displaced posterior cruciate ligament (PCL), avulsions, residual posterior laxity, and nonunions are underreported and the optimal technique is still unclear. The objective of our study is to differentiate the outcomes of arthroscopic suture pull-out (SPO) versus augmented suture pull-out (ASPO) using suture buttons for acute displaced tibial PCL avulsion fractures.

Methods: Retrospective study of ARIF for displaced tibial PCL avulsion operated between 2015 and 2021. Chronologically, the initial group of patients had undergone SPO (Group I), while the later underwent ASPO (Group II). Assessment included functional scores (International Knee Documentation Committee [IKDC]), Lysholm and Knee Injury and Osteoarthritis Outcome Score [KOOS]), and radiological assessment (union and posterior tibial displacement [PTD]). Student's unpaired t test and Cohen's term d for effect size were used to compare the groups. Intraclass correlation coefficient for assessing inter-observer reliability.

Results: Sixty four patients-Group I (n ​= ​32), Group II (n ​= ​32) were compared. |The mean duration of surgery was 48.06 (±9.52) and 54.3 (±6.97) in group I and II, respectively (p ​= ​0.004(s)). At mean follow-up of 39.7 months (SD-10.6) in Group I and 35.6 months (SD-6.6) in Group II, there was a statistically significant improvement in postoperative-IKDC, Lysholm, and KOOS scores (p ​< ​0.001). However, there was no significant difference between the two groups with respect to functional outcomes (P ​> ​0.05). Effect size (Cohen's-d) was 0.47 (medium for IKDC), 0.78 (large for Lysholms), 0.05 (small for KOOS), 1.46 (large for PTD). Mean PTD measuring the residual posterior laxity was greater in Group I (7.25 ​mm) (SD-1.9) than Group II (4.5 ​mm) (SD-2.1) and was statistically significant(P ​= ​0.001). There were two nonunions (6.6%) and one popliteal artery injury in Group I.

Conclusions: Both ASPO and SPO techniques result in comparable functional outcomes for ARIF of PCL avulsion fractures. However, augmented SPO with a suture button provides triple fixation and additional compression during ARIF of PCL avulsion fractures to mitigate residual posterior laxity on follow-up.

Level of evidence: Level III Retrospective cohort study.