Umer Butt1, Zainab Aqeel Khan2, Naila Zahir3, Zeeshan Khan4, Filip Vuletic5, Imran Shah2, Junaid Ali Shah2, Athar Muniruddin Siddiqui6, Damir Hudetz7. 1. AO Hospital, Karachi, Pakistan; Circle Bath Hospital, Bath, UK. Electronic address: drumerbutt@aol.com. 2. AO Hospital, Karachi, Pakistan. 3. Department of Histopathology and Cytology, Dr. Essa Laboratory and Diagnostic Centre, Karachi, Pakistan. 4. AO Hospital, Karachi, Pakistan; Hayatabad Medical Complex, Peshawar, Pakistan. 5. Department of Trauma and Orthopaedics, University Hospital Sveti Duh, Zagreb, Croatia. 6. AO Hospital, Karachi, Pakistan; Guys and St Thomas's NHS trust, London, UK. 7. University Hospital Sveti Duh, Zagreb, Croatia.
Abstract
BACKGROUND: We hypothesized that the torn anterior cruciate ligament (ACL) demonstrates a great healing response after initial trauma and has competent cells leading to the healing but differs in its response based on the type of tear and duration of injury. This study aimed to evaluate the histological and cellular responses to the injured ACL. METHODS: Fifty-two tissue samples from the ACL were harvested from patients undergoing arthroscopy. Detailed histological and cellular examinations were performed for ligament angiogenesis, fibrocytes, and synovial tissue infiltration. We compared the cellular response to injury in partially and completely ruptured ACLs. The duration of ACL injury and its response to cellular characteristics were also examined. Immunohistochemical studies using cluster of differentiation 34 (CD34) staining was used to evaluate endothelial cells and fibrocytes. RESULTS: We found a significantly higher density of synovial and ligament angiogenesis and fibrocytes at the torn end of ACL (Mann-Whitney, P < 0.050). Numerous fibrocytes were identified in complete ACL tears versus partial tears (Mann-Whitney = 0.020). Increased cellular proliferation was identified at the ruptured end of ACL remnant (Kruskal-Wallis, P < 0.050). The cellular proliferation of ruptured ACL decreased after 12 months. CONCLUSIONS: Based on our findings of the time-dependent decrease in the cellular response at the torn ends of the ACL, we recommend early intervention, preservation of the ACL remnant, and primary ACL repair or augmented reconstruction.
BACKGROUND: We hypothesized that the torn anterior cruciate ligament (ACL) demonstrates a great healing response after initial trauma and has competent cells leading to the healing but differs in its response based on the type of tear and duration of injury. This study aimed to evaluate the histological and cellular responses to the injured ACL. METHODS: Fifty-two tissue samples from the ACL were harvested from patients undergoing arthroscopy. Detailed histological and cellular examinations were performed for ligament angiogenesis, fibrocytes, and synovial tissue infiltration. We compared the cellular response to injury in partially and completely ruptured ACLs. The duration of ACL injury and its response to cellular characteristics were also examined. Immunohistochemical studies using cluster of differentiation 34 (CD34) staining was used to evaluate endothelial cells and fibrocytes. RESULTS: We found a significantly higher density of synovial and ligament angiogenesis and fibrocytes at the torn end of ACL (Mann-Whitney, P < 0.050). Numerous fibrocytes were identified in complete ACL tears versus partial tears (Mann-Whitney = 0.020). Increased cellular proliferation was identified at the ruptured end of ACL remnant (Kruskal-Wallis, P < 0.050). The cellular proliferation of ruptured ACL decreased after 12 months. CONCLUSIONS: Based on our findings of the time-dependent decrease in the cellular response at the torn ends of the ACL, we recommend early intervention, preservation of the ACL remnant, and primary ACL repair or augmented reconstruction.