title: Bone replacement of fast-absorbing biocomposite anchors in arthroscopic shoulder labral repairs.
abstract: BACKGROUND
  Newer generation biocomposite anchors are hypothesized to resorb more reliably and faster, while allowing for bone ingrowth and replacement.
  
  
  OBJECTIVE
  The purposes of this study were to (1) assess anchor resorption and bone ingrowth over time, (2) identify tunnel widening or potential reactions to the implants, (3) compare imaging findings for different sites of labral repair, and (4) determine patient subjective outcomes with the use of biocomposite anchors in glenoid labral repair.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  We enrolled 22 patients to participate in a 24-month outcomes study that included subjective and objective outcome assessments after glenoid labrum repair surgery. Magnetic resonance imaging (MRI) was performed at 6 and 12 months to identify any potential reactions to implants. Computed tomography (CT) scans were performed at 12 and 24 months to determine anchor resorption and bone ingrowth. Sixteen patients and 47 anchors were available for follow-up at 24 months. An independent, fellowship-trained musculoskeletal radiologist read the scans. Subjective outcome scores measured at 24 months postoperatively included Simple Shoulder Test, Tegner activity scale, American Shoulder and Elbow Surgeons (ASES), and University of California, Los Angeles (UCLA) shoulder scores.
  
  
  RESULTS
  No adverse events were reported with the use of biocomposite anchors at the end of the study period. At 12 and 24 months, respectively, CT scans demonstrated that an estimated 68% and 98% of combined anchor material had been absorbed, 56% and 78% of the anchor material had been replaced by soft tissue of variable density, and 9% and 20% of total anchor volume was replaced by bone. No obvious mechanical failure of the labral repairs was detected on nonarthrogram MRI. Three of the 47 anchors showed bone cyst formation. Tunnel widening (expansion beyond tunnel diameter of 3 mm; 2.9-mm drill hole utilized) was seen in 55% of the anchors but decreased between 12 and 24 months, consistent with bone replacement. Tunnel widening was seen more in anteroinferior and posterior glenoid anchor locations (84% and 57%, respectively) than in superior labral anchors (13%). Subjective outcome scores at 24 months for ASES and UCLA shoulder scores averaged 88 and 30, respectively. All but one patient were satisfied with their outcome at 24 months.
  
  
  CONCLUSIONS
  Our imaging evaluation indicates resorption of newer generation biocomposite anchors with progressive bone replacement at 12 and 24 months while maintaining acceptable subjective outcomes.
authors.affiliation: University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Milewski
authors.forename: David R
authors.initials: DR
authors.lastname: Diduch
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
authors.forename: Marc
authors.initials: M
authors.lastname: Tompkins
authors.forename: Shen-Ying
authors.initials: SY
authors.lastname: Ma
authors.forename: Cree M
authors.initials: CM
authors.lastname: Gaskin
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000009:adverse effects / Q000379:methods*; D001672:Biocompatible Materials / Q000378:metabolism*; D001845:Bone Cysts / Q000000981:diagnostic imaging / Q000209:etiology; D016025:Bone Transplantation / Q000379:methods*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D061165:Glenoid Cavity; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D012782:Shoulder / Q000000981:diagnostic imaging / Q000601:surgery*; D053441:Suture Anchors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001672:Biocompatible Materials