Histopathological and immunohistochemical study in the anterior and posterior cruciate ligament of the knee with rheumatoid arthritis in Iraqi patients

Background: Rheumatoid arthritis (RA) causes structural changes and inflammatory responses which damage the knee tissues that include the cruciate ligaments. Scientists will gain knowledge about ligament involvement in chronic joint diseases through their research to detect these changes.

Objective: The research aims to evaluate histopathological changes together with CD16 and CD68 protein expression and ecto-5’-nucleotidase (NTD/CD73) enzyme function in ACL and PCL tissues from RA patients who receive total knee arthroplasty.

Methods: Fifty ACL and fifty PCL samples were obtained from RA patients classified according to the 2010 ACR/EULAR criteria. The researchers conducted histopathology tests along with immunohistochemistry analysis of CD16 and CD68 markers and NTD enzyme histochemistry tests.

Results: Both ligaments exhibited fibrocyte proliferation, inflammatory infiltration, fibrin deposition, and vascular changes, with more pronounced alterations in the ACL. CD16 positivity reached 92% in the ACL and 96% in the PCL, whereas CD68 was positive in 98% of ACL samples and 94% of PCL samples. NTD activity ranged from weak to strong in both ligaments but showed higher scores in the ACL. Statistical analysis confirmed significant immunohistochemical and enzymatic differences between ACL and PCL.

Conclusion: The ACL and PCL tissues from RA patients show major inflammatory and degenerative damage which affects the ACL more than the PCL. The research results demonstrate how RA affects different ligaments but they do not provide any evidence to support removing cruciate ligaments as a treatment option. The research requires non-RA controls to establish the relationship between enzyme activity and staining intensity.