Case Report Staphylococcus lugdunensis Septic Arthritis following Arthroscopic Anterior Cruciate Ligament Reconstruction Saygin Kamaci, 1,2 Yehia H. Bedeir , 2,3 Christopher J. Utz, 2 and Angelo J. Colosimo 2 1 Department of Orthopaedic Surgery, Hacettepe University, Turkey 2 University of Cincinnati Medical Center, Cincinnati, OH, USA 3 Department of Orthopaedic Surgery, University of Alexandria, Egypt Correspondence should be addressed to Yehia H. Bedeir; yehiabedeir@hotmail.com Received 16 November 2019; Revised 6 January 2020; Accepted 7 January 2020; Published 20 January 2020 Academic Editor: Koichi Sairyo Copyright © 2020 Saygin Kamaci et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Summary. We report two cases of Staphylococcus lugdunensis (S. lugdunensis) septic arthritis following arthroscopic anterior cruciate ligament (ACL) reconstruction. Both initial surgical procedures were ACL reconstruction along with simultaneous collateral ligament and meniscus procedures. Patients presented with septic arthritis three and ten weeks following the index procedure. Both patients successfully recovered with early arthroscopic irrigation, debridement, and synovial culture, in addition to long-term parenteral and oral antibiotics. 1. Introduction Septic arthritis following anterior cruciate ligament (ACL) reconstruction is a rare (0.1-1.7%) but potentially devastating complication [1]. Postoperative septic arthritis has a negative impact on both short- and long-term outcomes of ACL reconstruction [2, 3]. Severe sequelae like full thickness carti- lage lesions, degenerative arthritis, and osteomyelitis can be seen. Since cartilage loses more than half of its glycosamino- glycan and collagen content within seven days from the onset of infection, early diagnosis and prompt aggressive treatment are crucial to avoid potentially dramatic sequelae. The main goal of treatment is first to protect the articular cartilage, with a secondary goal of protecting the graft tissue. Serial arthro- scopic joint debridement and lavage along with antibiotic treatment provides successful elimination of the infection and graft preservation [4]. Like other coagulase-negative staphylococcus species, widespread colonization of Staphylococcus lugdunensis (S. lugdunensis) in the human skin may play a role in poten- tial dissemination. Skin and soft tissue infections and endocar- ditis are the most frequent manifestations of an S. lugdunensis infection. S. lugdunensis has been reported in the orthopaedic literature, associated with osteoarticular joint infections, prosthetic joint infections, osteomyelitis, infections related with fracture fixation devices, and arthroscopic ACL recon- struction [5]. We present the second report in the literature of two cases of S. lugdunensis septic arthritis following arthroscopic ACL reconstructions. 2. Case Reports 2.1. Case 1. The first case was a 20-year-old male patient who presented to the emergency department with right knee pain and increased swelling ten weeks following ACL reconstruc- tion with a bone-patellar tendon-bone (BPTB) autograft, fib- ular collateral ligament (FCL) repair with augmentation with semitendinosus allograft, and a lateral partial meniscectomy. Vital signs were within normal limits. C-reactive protein (CRP) level was 26 mg/l and erythrocyte sedimentation rate (ESR) was 5 mm/h. Knee joint aspiration showed yellow, tur- bid aspirate consisting of 82,000/mm 3 neutrophils. Arthro- scopic knee joint irrigation, synovial debridement and synovial biopsy/culture (I&D) were performed the next day. Arthroscopy revealed an intact and well-synovialized ACL Hindawi Case Reports in Orthopedics Volume 2020, Article ID 2813134, 3 pages https://doi.org/10.1155/2020/2813134