Augmented suture pull-out with suture-button(triple fixation) yields less radiological residual laxity than suture pull-out technique-for Arthroscopic reduction and internal fixation 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 non-unions are under reported 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 button for acute displaced tibial PCL avulsion fractures.

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

Results: 64 patients-Group I(n=32),Group II(n=32) were compared. |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 39.7months(SD-10.6) in Group I and 35.6months(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 (4.5mm)(SD-2.1) and was statistically significant(P=0.001). There were two non-unions (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.