AB0840 Comparative analysis of macroscopic changes in bone tissue of heads and acetabulums of the hip joints (HJ) in patients with ankylosing spondylitis (AS): data from a retrospective analysis

Abstract

BackgroundAccording to the results of Russian studies, coxitis occurs in 56% of patients (pts) with AS. At the same time, the need for total hip arthroplasty (THA) is only 8%, which is associated with the use of biologic disease-modifying anti-rheumatic drugs (bDMARDs).ObjectivesThe aim of the study was to compare macroscopic changes in bone tissue of femoral heads (FH) and acetabulums in pts with AS who received and did not receive bDMARDs.MethodsThe retrospective study included 170 pts with a verified diagnosis of AS, who met the modified New York criteria of 1984, who were treated in the traumatological and orthopedic department in the period from 1998 to 2020, THA was routinely performed to all pts. Most of them were male (80.6%). The average age was 38.1±11.3 yrs. 82.9% of pts had low activity of the disease according to the BASDAI index at the time of surgical treatment and 17.1% of them had high activity. Nonsteroidal anti-inflammatory drugs were received by 61.7% of pts, sulfasalazine - 20.6%, methotrexate - 7.7%, systemic glucocorticoids - 8.8%, bDMARDs -53 (31.1%).Results:ParameterAll patients (n=170)bDMARDs (+) n=53bDMARDs (-) n=117Average duration of the disease, years, M±ϭ17,0±8,516,2±8,017,5±8,7Age at the time of diagnosis, years, M±ϭ27,6±9,127,6±10,027,6±8,9Necessity of THA, years, M±ϭ7,4±4,86,0±2,88,0±5,4Osteophytes (Yes/No),%90/1096/488/12Protrusion (Yes/No),%75/2568/3278/12Granulation (Yes/No),%91/995/589/11Ankylosis (Yes/No),%47/5348/5237/53Ankylosis (Fibrous/Osseous),%77/2380/2075/25Cysts of femoral heads (Yes/No),%39/6136/6439/61Cysts of femoral heads (Single/multiple),%78/2270/3071/29Erosion of femoral heads,%473950Osteonecrosis of femoral heads,%75,575*45*p<0,05The vast majority (85.9%) of pts had III grade of secondary coxarthrosis and 14.1% - had IV grade before THA. Complete absence of cartilage on the surface of acetabulum was revealed in 71.7% of cases, and there were either partial abrasions of the cartilage in the places of maximal load (6.5%), or chondromalacia (21.8%) in rest of the pts. Deformity of the FH was detected in 98.2% of pts, while as a result of osteonecrosis of FH (ONFH) in 75.5%. Complete absence of cartilage on FH was in 130 (76.5%) pts, and there were either partial abrasions of the cartilage in the places of maximal load (11.2%), or chondromalacia (12.3%) in rest of the pts. There were no significant differences in the macroscopic picture of the lesion of FH and acetabulums of HJ in pts with and without intake of bDMARDs, except for a higher frequency of ONFH in pts receiving bDMARDs.ConclusionThe need for THA arose on average after 7.4±4.8 yrs from the appearance of pain in the hip joint (HJ). Macroscopic picture of HJ lesion in pts with AS was characterized as ONFH in 75.5% of cases, in almost half of cases - ankylosis of HJ, mainly fibrous (77.2%) with complete or partial absence of cartilage in acetabular surface and FH. According to the majority of macroscopic changes in the bone tissue of HF and acetabulums of HJ, pts with and without bDAMRDs did not differ, but the frequency of ONFH was significantly higher in the group of pts who was receiving bDAMRDs.Disclosure of InterestsNone declared.