Morphological features of the synovial membrane in patients with osteoarthritis after knee arthroplasty

BACKGROUND: Inflammation of the synovial membrane is a common manifestation in osteoarthritis which plays a role in complex pathophysiology of osteoarthritis. Synovitis leads to complications during knee replacement. AIM: To give clinical and morphological characteristics of the knee joint condition by histological assessment of the synovial membrane. MATERIALS AND METHODS: In the clinic of traumatology and orthopedics of North-Western State Medical University named after I.I. Mechnikov in 2022, 187 total knee arthroplasty operations were performed in patients with osteoarthritis. For morphological study of the synovial membrane of the knee joint biopsy specimens were taken from 30 patients (19 women and 11 men) by randomized sampling method. The age of patients: from 40 to 76 years, the average age was 59,3 ± 6,7 years. Immunohistochemical reactions were performed to characterize the cellular composition of the inflammatory infiltrate; antibodies to CD68, CD3, CD20, CD138, Ki-67 were used. Morphometry was performed at ×400 magnification. RESULTS: Only 48 (25.7%) patients had at least one course of inpatient conservative or minimally invasive surgical treatment for osteoarthritis of the knee joint before total knee arthroplasty. 18 (9.6%) patients had intraoperative and postoperative complications. Among 30 morphological studies conducted, 3 (10%) patients had verified stage I osteoarthritis of the knee joint, 8 (26.7%) were diagnosed with stage II osteoarthritis, and 19 (63.3%) — stage III osteoarthritis. Significant correlation was obtained between cells stained with antibodies to CD3 and CD20 (r = 0.69; p 0.05), CD68 and CD138 (r = 0.66; p 0.05). Cluster analysis identified three groups of patients with severe (10%), moderate (30%) and weak/absent infiltration (60%). CONCLUSIONS: To correct the treatment strategy for patients with osteoarthritis of the knee joint, it is advisable to strengthen the role of arthroscopic methods in the diagnostic and treatment processes.