Impact of infrapatellar fat pad injury severity on subsequent patellofemoral cartilage degeneration following acute ACL tear.

Abstract

The infrapatellar fat pad (IFP) is important in the homeostasis of the knee joint due to its structural and immune-modulating properties. This study investigates the relationship between IFP injury severity during acute Anterior Cruciate Ligament (ACL) tears, and the future development of Patellofemoral Compartment (PFC) chondrosis. Adult participants aged 18-45 years old who were known to have first-time ACL tears between 01/01/2009 and 10/1/2022 were included. Patients with concomitant knee pathologies at the time of injury were excluded from the study. All participants received ACL reconstruction surgery and had follow-up MRIs conducted within two years postoperatively. Preoperative IFP edema levels were assessed alongside both pre-and postoperative PFC. We analyzed the relationship between the initial IFP edema and future PFC progression on subsequent MRI scans. A total of 69 participants were included in this study. No significant correlation was found between the severity of initial IFP injury and the initial presence of PFC chondrosis (r = -0.04, P = 0.61). However, a significant positive correlation was observed between the severity of initial IFP injury and the future progression of PFC chondrosis (r = 0.44, P < 0.001). Additionally, a significant difference in the progression of PFC chondrosis was noted when comparing grade 1 to grade 2 IFP injuries (P = 0.001). No significant difference in PFC chondrosis development was identified when comparing grade 2 to grade 3 IFP injuries (P = 0.72). Our study underscores the potential role of the IFP in preserving cartilage homeostasis by establishing a link between the severity of IFP injury and the subsequent development of PFC following ACL injury.