title: Efficacy of Direct Injection of Etanercept into Knee Joints for Pain in Moderate and Severe Knee Osteoarthritis.
abstract: OBJECTIVE
  Osteoarthritic (OA) pain is largely considered to be inflammatory pain. However, during the last stage of knee OA, sensory nerve fibers in the knee are shown to be significantly damaged when the subchondral bone junction is destroyed, and this can induce neuropathic pain. Several authors have reported that tumor necrosis factor-α (TNFα) in a knee joint plays a crucial role in pain modulation. The purpose of the current study was to evaluate the efficacy of etanercept, a TNFα inhibitor, for pain in knee OA.
  
  
  METHODS
  Thirty-nine patients with knee OA and a 2-4 Kellgren-Lawrence grading were evaluated in this prospective study. Patients were divided into two groups; hyaluronic acid (HA) and etanercept injection. All patients received a single injection into the knee. Pain scores were evaluated before and 4 weeks after injection using a visual analogue scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and they were compared between the groups.
  
  
  RESULTS
  Before injection, VAS and WOMAC scores were not significantly different between the groups (p>0.05). Significant pain relief was found in the etanercept group at 1 and 2 weeks by VAS, and at 4 weeks by WOMAC score, compared with the HA group (p<0.05). No adverse events were observed in either group.
  
  
  CONCLUSIONS
  Direct injection of etanercept into OA knee joints was an effective treatment for pain in moderate and severe OA patients. Furthermore, this finding suggests that TNFα is one factor that induces OA pain.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. sohtori@faculty.chiba-u.jp.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yawara
authors.initials: Y
authors.lastname: Eguchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Nobuyasu
authors.initials: N
authors.lastname: Ochiai
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Kishida
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kuniyoshi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Aoki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyagi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kamoda
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Gou
authors.initials: G
authors.lastname: Kubota
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sakuma
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Oikawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Inage
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sainoh
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shiga
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Abe
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kanamoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Toyone
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000368:Aged; D000068800:Etanercept / Q000008:administration & dosage* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy; D020370:Osteoarthritis, Knee / Q000188:drug therapy*; D010147:Pain Measurement; D011446:Prospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha; D055675:Viscosupplements / Q000008:administration & dosage / Q000627:therapeutic use*; D064232:Visual Analog Scale
chemical_list: C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D055675:Viscosupplements; D006820:Hyaluronic Acid; D000068800:Etanercept
keywords: Etanercept; knee osteoarthritis; pain