title: Hylan G-F 20 Versus Low Molecular Weight Hyaluronic Acids for Knee Osteoarthritis: A Meta-Analysis.
abstract: BACKGROUND
  Hyaluronic acid injection has been reported to decrease pain compared with baseline levels in knee joint osteoarthritis. Hylan G-F 20 is distinguished from the other products by its chemical structure and relatively higher molecular weight. Many trials have compared hylan G-F 20 and low molecular weight hyaluronic acids (LMWHAs); however, their relative efficacy and safety are still debated.
  
  
  OBJECTIVE
  The aim was to compare the effectiveness and safety of intra-articular injection of hylan G-F 20 and LMWHA in the treatment of knee joint osteoarthritis.
  
  
  METHODS
  A comprehensive search of the literature up to February 2016 was performed; multiple databases were searched with 'Synvisc' or 'hylan' or 'hyaluronan' as free word terms. The pain-related outcomes and treatment-related adverse events from intent-to-treat analyzed studies were pooled for meta-analysis; other functional outcomes were included in the qualitative analysis.
  
  
  RESULTS
  Twenty trials with a total of 3034 patients and 3153 knees were included, with a pooled dropout rate of 7.2 %. The pooled pain-related outcomes at 2 to 3 months reached a statistically significant difference in favor of hylan G-F 20 (I2= 88 %; random effects; P = 0.02), and the significance still existed with exclusion (in order to eliminate heterogeneity) of the three studies that most favored hylan G-F 20 (I2= 51 %; fixed effect; P = 0.03). No significant difference was reached for other group and subgroup analyses. No significant difference was reached in comparing the patients with treatment-related adverse events (seven trials; 2025 patients; P = 0.13) or the treatment-related adverse events (six trials; 1633 patients; P = 0.14).
  
  
  CONCLUSIONS
  According to the current results, limited evidence showed a superior effect favoring hylan G-F 20 over LMWHA in the period from 2 to 3 months post-injection for pain-related outcomes. There was no evidence of increased risk of treatment-related adverse events for hylan G-F 20 injections.
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China. zhao_hongmou@hotmail.com.
authors.forename: Hongmou
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Liu
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liang
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China.
authors.forename: Junhu
authors.initials: J
authors.lastname: Wang
authors.affiliation: Foot and Ankle Surgery Department, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, 710054, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Liu
mesh_terms: D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D008970:Molecular Weight; D020370:Osteoarthritis, Knee / Q000188:drug therapy*; D010146:Pain / Q000188:drug therapy; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; C049816:hylan; D006820:Hyaluronic Acid