Summary

Concomitant injury and treatment patterns differ between patients undergoing early (<12 weeks) and delayed (>12 weeks) multiligament PCL reconstruction (PCL-R).

Abstract

Introduction

The optimal timing of surgery for multiligament knee injuries (MLKIs) is currently unclear. Persistent instability in MLKIs involving the posterior cruciate ligament (PCL) may contribute to further intraarticular and ligamentous injury. The aim of this study was to investigate differences in concomitant injury patterns and their treatment in patients undergoing early (<12 weeks) and delayed (>12 weeks) multiligament PCL reconstruction (PCL-R).

Methods

This retrospective chart review included patients undergoing multiligament PCL-R at a single institution between 2008 and 2020. Multiligament PCL-R was defined as PCL-R and concurrent surgical treatment of one or more additional knee ligaments, including the anterior cruciate ligament (ACL), medial collateral ligament/posteromedial corner, and lateral collateral ligament/posterolateral corner (LCL/PLC). Exclusion criteria included isolated PCL-R, PCL repair and missing surgical data with respect to any variable. Patients were dichotomized into early and delayed surgery groups based on whether time elapsed between injury and surgery was shorter or longer than 12 weeks. Demographics, injury mechanism, and concomitant ligament, meniscus, and cartilage injury data were extracted. Between-group comparisons of categorical variables were conducted with Chi-square or Fisher’s exact tests, and continuous variables were compared with independent samples t-tests. Post-hoc comparisons were adjusted for multiplicity with the Bonferroni-Hochberg procedure. Level of significance was set at p<0.05.

Results

A total of 148 patients were deemed eligible for analysis. There were 57 (38.5%) patients in the early multligament PCL-R group, and 91 (61.5%) patients in the delayed multiligament PCL-R group. The mean time from injury to surgery was 6±3.1 weeks in the early PCL-R group, compared to 63.7±116.1 weeks in the delayed PCL-R group. While concomitant LCL/PLC reconstruction was performed in 55 (60%) of delayed multiligament PCL-Rs and 23 (40%) of early PCL-Rs (p=0.02), there was no significant between-group differences in the frequencies of other concomitant ligament surgeries performed. There were no significant differences in the prevalence of meniscus tears between the early (n=28,49%) and delayed (n=36,40%) multiligament PCL-R groups (p=0.25). Concomitant meniscus surgery was significantly more prevalent in the early (n=25,44%) versus delayed (n=19,21%) multiligament PCL-R group (p=0.003), with a significantly greater proportion of medial meniscus surgeries performed in the early (n=16,28%) compared to delayed (n=13,14%) PCL-R group (p=0.04). The prevalence of knee cartilage injury was significantly different between the early (n=12,24%) and delayed (n=41,46%) multiligament PCL-R groups (p=0.01), with a more frequent involvement of the lateral (n=17,19% vs. n=3,5%, respectively; p=0.04) and medial (n=31,34% vs. n=6,11%, respectively; p=0.005) femoral condyles in the delayed compared to the early PCL-R group.

Conclusion

Patients undergoing delayed multiligament PCL-R demonstrated a higher rate of cartilage pathology, specifically of the lateral and medial femoral condyles, when compared to patients undergoing early PCL-R. Delayed multiligament PCL-R may lead to increased chondral damage, potentially due to knee instability. Despite similar rates of medial meniscus injury in both groups, medial meniscus surgery is more prevalent in early multiligament PCL-R and suggests that surgical timing may impact the treatability of concomitant meniscus pathology. Additionally, acute management of instability in this population may prevent the development of posterolateral knee instability.