title: Fixation of osteochondritis dissecans lesions using poly(l-lactic acid)/ poly(glycolic acid) copolymer bioabsorbable screws.
abstract: BACKGROUND
  Many osteochondritis dissecans lesion fixation techniques are effective. A new absorbable copolymer screw may be suitable for this application.
  
  
  OBJECTIVE
  To characterize the mechanical and in vitro absorption properties of a copolymer fixation screw and determine the clinical efficacy of using the screw to fix osteochondritis dissecans lesions.
  
  
  METHODS
  Case series and laboratory study; Level of evidence, 4.
  
  
  METHODS
  Seven patients diagnosed with unstable, partially open osteochondritis dissecans lesions were treated with debridement of the bed and fixation with 2.5-mm diameter screws made of LactoSorb copolymer; the patients were nonweightbearing for 6 weeks. Clinical and radiographic follow-up was for 25 to 37 months. Biomechanical testing was performed in synthetic bone over a 12-week period on buffer-incubated specimens.
  
  
  RESULTS
  Six of the 7 osteochondritis dissecans lesions healed clinically and radiographically; the osteochondritis dissecans fragment was removed from the seventh patient (unhealed). No symptoms indicative of an inflammatory reaction related to the presence of the absorbable screws, including recurrent effusion, warmth, or erythema, were noted. In the in vitro testing, the initial average peak pull-out and shear loads were 20.1 kg and 22.3 kg, respectively, with little strength remaining at 12 weeks.
  
  
  CONCLUSIONS
  In general, the 2.5-mm-diameter LactoSorb copolymer screws provided adequate stability for healing of osteochondritis dissecans lesions and degraded without an inflammatory response by the body.
authors.affiliation: Department of Orthopaedics, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA. larsensa@yahoo.com
authors.forename: Mitchell W
authors.initials: MW
authors.lastname: Larsen
authors.forename: William S
authors.initials: WS
authors.lastname: Pietrzak
authors.forename: Jesse C
authors.initials: JC
authors.lastname: DeLee
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005260:Female; D006801:Humans; D007249:Inflammation; D007593:Joint Instability; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D010008:Osteochondritis Dissecans / Q000601:surgery*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011183:Postoperative Complications; D016896:Treatment Outcome
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid