Summary

Both Augmented suture pull out and Suture pull out techniques result in comparable functional outcomes for ARIF of PCL avulsion fractures. However, augmenting with suture button results in less residual posterior laxity than suture pull out alone. Thus it may be prudent to augment SPO with a suture button during ARIF of PCL avulsion fractures to mitigate residual posterior laxity on follow-up.

Abstract

Objectives : Among numerous arthroscopic reduction and internal fixation (ARIF) techniques for displaced posterior cruciate ligament (PCL) avulsions, the optimal technique is still unclear. Though, suture pull out(SPO) technique has been widely employed for ARIF of PCL bony avulsions with good outcomes, augmenting this construct with a suture button is known to provide additional stability and negate the possibility of secondary loosening leading to non-union/ increased residual posterior laxity. However there is only limited evidence in the literature in this regard and requires more light to justify usage of additional fixation. The objective of our study is to compare the clinical and radiological outcomes of arthroscopic suture pull out (SPO) versus augmented suture pull out (ASPO) using suture button for acute displaced tibial PCL avulsion fractures.

Methods

Patients undergoing ARIF for displaced tibial PCL avulsion operated between 2015 to 2021 were retrospectively reviewed. Chronologically the initial group of patients had undergone SPO (Group I) while the later underwent ASPO (Group II). Assessment included pre- and post-operative functional scores using IKDC (International Knee Documentation Committee), Lysholm and KOOS scores(Knee Injury and Osteoarthritis outcome score), radiological assessment of union and posterior tibial displacement (PTD) using stress radiography. For statistical analysis, student’s unpaired t test was used to compare continuous variables between the two groups. Intraclass correlation coefficient was used for assessing inter observer reliability.

Results

A total of 64 patients-Group A(n=32), Group B(n=32) were included for final analysis . At a mean follow up of 39.7months(SD-10.6) in Group I and 35.6months(SD-6.6) in Group II, both groups showed significant improvement in IKDC, Lysholm and KOOS scores. However, there was no statistically significant difference between the two groups with respect to functional outcomes (P >0.05). The mean PTD was greater (mean=7.25 mm±1.9) in Group I than Group II (mean= 4.5mm±2.1) and the difference was found to be statistically significant(P=0.001). There were two non-unions (6.6%) and one popliteal artery injury in Group I.

Conclusions

Both SPO and ASPO techniques result in comparable functional outcomes for ARIF of PCL avulsion fractures. However, augmenting with suture button results in less residual posterior laxity than suture pull out alone. Thus it may be prudent to augment SPO with a suture button during ARIF of PCL avulsion fractures to mitigate residual posterior laxity on follow-up.