{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T04:58:01Z","timestamp":1781153881387,"version":"3.54.1"},"reference-count":0,"publisher":"Indian Orthopaedic Research Group","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Jocr"],"published-print":{"date-parts":[[2026]]},"abstract":"<jats:p>Introduction: Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a serious complication whose diagnosis relies on a combination of serum and synovial biomarkers. Inflammatory non-infectious conditions can fulfil these same diagnostic criteria, creating a diagnostic and therapeutic challenge. We report the first case, to our knowledge, of antiphospholipid syndrome (APS)\u2013associated livedoid vasculopathy (LV) mimicking recurrent PJI.\n\nCase Report: A 74-year-old White male with a remote history of uncomplicated right TKA presented with two discrete episodes of presumed PJI (November 2025 and January 2026), each coinciding with a new right ankle lesion. Synovial fluid analysis on both occasions demonstrated markedly elevated white blood cell counts (WBC) (20,688 and 28,900 cells\/\u00b5L; &gt;93% neutrophils) and a positive synovasure \u03b1-defensin, yielding a 2018 International Consensus Meeting score of 10 on each presentation. Cultures and next-generation sequencing (NGS) were uniformly negative. The ankle lesions were ultimately biopsied and confirmed histologically as LV. Serology subsequently established a double-positive APS profile (positive lupus anticoagulant and anti-\u03b22-glycoprotein I antibodies). All antimicrobials were discontinued; the patient declined two-stage revision arthroplasty. Repeat aspiration 3 weeks later showed completely normal synovial fluid (WBC 28 cells\/\u00b5L, synovial C-reactive protein 0.01 mg\/L). At 12 weeks off all therapy, the patient remains asymptomatic.\n\nConclusion: APS-associated LV can produce a thrombo-inflammatory sterile synovitis that satisfies established PJI diagnostic criteria, including a positive \u03b1-defensin. This case underscores the importance of evaluating concomitant dermatologic lesions, pursuing advanced microbiologic testing (NGS) before committing to surgical intervention, and considering hypercoagulable states in PJI workups with persistently negative cultures.\n\nKeywords: Antiphospholipid syndrome, livedoid vasculopathy, periprosthetic joint infection, alpha-defensin, sterile synovitis, total knee arthroplasty, next-generation sequencing.<\/jats:p>","DOI":"10.13107\/jocr.2026.v16.i06.7474","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T04:17:56Z","timestamp":1781151476000},"page":"361-365","source":"Crossref","is-referenced-by-count":0,"title":["Antiphospholipid Syndrome\u2013Associated Livedoid Vasculopathy Mimicking Recurrent Periprosthetic Joint Infection after Total Knee Arthroplasty: A Case Report"],"prefix":"10.13107","volume":"16","author":[{"given":"Michael","family":"Booth","sequence":"first","affiliation":[{"name":"Department of Orthopaedics, Ohio State University, Columbus, Ohio, United States,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nina","family":"Couette","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, Ohio State University, Columbus, Ohio, United States."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"5271","published-online":{"date-parts":[[2026]]},"container-title":["Journal of Orthopaedic Case Reports"],"original-title":[],"deposited":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T04:18:02Z","timestamp":1781151482000},"score":1,"resource":{"primary":{"URL":"https:\/\/jocr.co.in\/wp\/2026\/06\/antiphospholipid-syndrome-associated-livedoid-vasculopathy-mimicking-recurrent-periprosthetic-joint-infection-after-total-knee-arthroplasty-a-case-report\/"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":0,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026]]},"published-print":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.13107\/jocr.2026.v16.i06.7474","relation":{},"ISSN":["2321-3817"],"issn-type":[{"value":"2321-3817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026]]}}}