Role of prokineticin-2 and cytokines in synovial fluid in traumatic anterior cruciate ligament injuries

Background: Anterior cruciate ligament (ACL) tears induce a proinflammatory intra-articular environment. Despite successful ACL reconstruction (ACLR), post-traumatic osteoarthritis (PTOA) incidence remains high. The role of prokineticin-2 (PK2), a novel inflammatory and pain mediator, was investigated in this observational study of traumatic ACL injuries, associated with meniscal tears. Methods: Twenty patients with isolated ACL tears (ACL group) and 20 with associated meniscal injury (ACL + M group) were enrolled. Synovial fluid PK2, IL-10, and TNF-α levels were measured using ELISA method. Patients underwent long-term follow-up (minimum 5 years) with clinical reassessment using patient-reported outcome measures (PROMs) (IKDC, Lysholm, Tegner activity scale, SKV). Results: PK2 was detected in both ACL and ACL + M groups without significant differences. Higher PK2 levels were associated with hemarthrosis and correlated positively with IL-10. No associations were found between PK2 levels and demographic factors or time from injury. At follow-up, PK2 negatively correlated with IKDC, Lysholm, and SKV scores. Conclusion: This study provides initial evidence of PK2 in synovial fluid following ACL injury, suggesting its potential role in knee inflammation. PK2 may represent a candidate biomarker involved in the post-traumatic inflammatory microenvironment; however, further longitudinal studies including structural outcomes are needed.