title: Outcomes after Total Knee Arthroplasty for post-traumatic arthritis.
abstract: BACKGROUND
  Total Knee Arthroplasty (TKA) is an important treatment for posttraumatic arthritis (PTA), but evidence on outcomes is sparse. The purpose of this study was to evaluate the impact of PTA versus primary osteoarthritis (OA) on postoperative outcomes after TKA.
  
  
  METHODS
  We queried the entire Medicare database from 2005 to 2012. International Classification of Diseases, 9th revision and Current Procedural Terminology codes were used to identify the procedure, indication, and complications. Patients with minimum two-years follow-up were selected. Odds ratios (ORs), confidence intervals, and p-values (p) were calculated.
  
  
  RESULTS
  For PTA, 3509 patients had TKA. For OA, 257,611 patients with TKA served as controls. The average Charlson Comorbidity Index for both groups was five. PTA patients were younger; only eight out of 29 Elixhauser comorbidities were higher. PTA patients had higher incidence of periprosthetic infection (OR 1.72, p<0.001), cellulitis or seroma (OR 1.19, p<0.001), knee wound complications (OR 1.80, p<0.001), TKA revision (OR 1.23, p=0.01), and arthrotomy/incision and drainage (OR 1.55, p<0.001). Blood transfusion rate was lower in PTA patients. There were no significant differences in bleeding complications, prosthetic dislocation, broken prostheses, periprosthetic fracture, osteolysis and polywear, neurovascular injury, and extensor mechanism rupture.
  
  
  CONCLUSIONS
  This study represents, to our knowledge, TKA outcomes in the largest cohort of PTA patients to date. Our findings indicate that these patients are at higher risk for many, but not all, postoperative surgical complications despite being as healthy as patients receiving TKA for primary OA.
authors.affiliation: Duke University School of Medicine, Duke University Medical Center, Box 3269, Durham, NC 27710, United States. Electronic address: abirambala@gmail.com.
authors.forename: Abiram
authors.initials: A
authors.lastname: Bala
authors.affiliation: Duke University School of Medicine, Duke University Medical Center, Box 3269, Durham, NC 27710, United States. Electronic address: colin.penrose@dm.duke.edu.
authors.forename: Colin T
authors.initials: CT
authors.lastname: Penrose
authors.affiliation: Division of Adult Reconstruction, Department of Orthopaedic Surgery, Duke University Medical Center, Box 3000, Durham, NC 27710, United States. Electronic address: thorsten.seyler@dm.duke.edu.
authors.forename: Thorsten M
authors.initials: TM
authors.lastname: Seyler
authors.affiliation: Department of Orthopaedic Surgery, 4709 Creekstone Dr, Durham, NC 27703, United States. Electronic address: richard.mather@dm.duke.edu.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Mather
authors.affiliation: Division of Adult Reconstruction, Department of Orthopaedic Surgery, Duke University Medical Center, Box 3447, Durham, NC 27710, United States. Electronic address: samuel.wellman@dm.duke.edu.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Wellman
authors.affiliation: Division of Adult Reconstruction, Duke University Medical Center, Box 3269, Durham, NC 27710, United States; Total Joint Fellowship Department of Orthopaedic Surgery, Duke University Medical Center, Box 3269, Durham, NC 27710, United States. Electronic address: michael.bolognesi@dm.duke.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Bolognesi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000150:complications* / Q000601:surgery; D008297:Male; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000601:surgery*; D011788:Quality of Life; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Outcomes; Posttraumatic arthritis; Total knee arthroplasty