title: Causes of Aseptic Persistent Pain after Total Knee Arthroplasty.
abstract: BACKGROUND
  Persistent pain after total knee arthroplasty (TKA) is dissatisfying to the patient and frustrating to the surgeon. The purpose of this study is to evaluate the aseptic causes and clinical course of intractable pain following TKA.
  
  
  METHODS
  Of the total 2,534 cases of primary TKA reviewed, 178 cases were classified as having aseptic persistent pain that was not resolved within 1 year after surgery. Except for the cases with periprosthetic fracture (56 knees), 122 cases of aseptic painful TKA were divided into two groups: intra-articular group (83 knees) and extra-articular group (39 knees).
  
  
  RESULTS
  In the intra-articular group, the main reasons for pain were aseptic loosening (n = 40), polyethylene wear (n = 16), instability (n = 10), recurrent hemarthrosis (n = 5), patellar maltracking (n = 4), tendon ruptures (n = 4), and stiffness (n = 2). In the extraarticular group, 10 knees (25.6%) were found to have nerve entrapment in the spine, 6 knees (15.4%) were found to have hip osteoarthritis or femoral head avascular necrosis. The reasons for persistent knee pain in the remaining 23 knees (59.0%) still remain elusive.
  
  
  CONCLUSIONS
  Persistent pain after TKA originated from pathology of extra-articular origin in a considerable number of cases in this study. Therefore, it is important to perform thorough preoperative evaluations to reduce pain resulting from extra-articular causes. Furthermore, meticulous surgical procedures and optimal alignment are required to reduce pain of intra-articular origin related to implant wear, instability, and patellar maltracking.
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Hong-An
authors.initials: HA
authors.lastname: Lim
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Eun-Kyoo
authors.initials: EK
authors.lastname: Song
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Seon
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Kyung-Soon
authors.initials: KS
authors.lastname: Park
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Shin
authors.affiliation: Department of Orthopaedic Surgery, Center for Joint Disease, Chonnam National University Bitgoeul Hospital, Gwangju, Korea.
authors.forename: Hong-Yeol
authors.initials: HY
authors.lastname: Yang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000209:etiology*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D005271:Femur Head Necrosis / Q000150:complications; D006801:Humans; D007593:Joint Instability / Q000150:complications; D008297:Male; D008875:Middle Aged; D009408:Nerve Compression Syndromes / Q000150:complications; D015207:Osteoarthritis, Hip / Q000150:complications; D010148:Intractable Pain / Q000000981:diagnostic imaging / Q000209:etiology*; D010149:Postoperative Pain / Q000000981:diagnostic imaging / Q000209:etiology*; D010329:Patella / Q000503:physiopathology; D011475:Prosthesis Failure / Q000009:adverse effects; D011859:Radiography
keywords: Causes; Chronic pain; Non-infective; Total knee arthroplasty