title: Two-year follow-up study on clinical and radiological outcomes of polyurethane meniscal scaffolds.
abstract: BACKGROUND
  Little is known about radial displacement (RD) of polyurethane (PU) scaffolds, intended for partial meniscus defect substitution; no data are available on whether rim thickness influences RD and whether RD correlates with clinical outcome scores.
  
  
  OBJECTIVE
  The meniscus is not extruded preoperatively, but RD occurs after scaffold implantation. A thicker rim will limit RD, and there is no correlation between RD and clinical outcome.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Twenty-six patients were implanted with a PU scaffold (8 lateral, 18 medial). Radial displacement (mm) was evaluated on magnetic resonance images preoperatively and at 3 months, 1 year, and 2 years postoperatively. At each time point, it was determined whether a correlation existed between the rim and RD. Clinical outcome was determined using a visual analog scale (VAS) for pain as well as the Lysholm knee scoring scale, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) score.
  
  
  RESULTS
  Radial displacement of lateral scaffolds was not significantly different (P = .178) either preoperatively (mean ± SD, 3.42 ± 0.99 mm) or at 3 months (4.82 ± 0.59 mm), 1 year (4.55 ± 0.87 mm), or 2 years postoperatively (4.10 ± 0.93 mm). No correlation was observed between the rim and lateral RD at all time points. Medial scaffold RD increased significantly (P < .001) from preoperative values (2.17 ± 0.84 mm) to those at 3 months (4.25 ± 0.89 mm), 1 year (4.43 ± 1.01 mm), and 2 years postoperatively (4.41 ± 0.96 mm). A strong negative correlation between medial RD and the rim was observed at all time points. There was no significant correlation between clinical outcome scores and RD, either preoperatively or postoperatively.
  
  
  CONCLUSIONS
  This study demonstrated that limited medial meniscal RD was present preoperatively but increased by 2 mm after scaffold implantation. Lateral RD was also present preoperatively but did not increase after scaffold implantation. Importantly, a strong negative correlation was found between the rim and postoperative medial RD; a thicker rim limited RD. However, in the lateral compartment, rim thickness did not correlate with RD because RD was already strongly present preoperatively. Finally, no correlations were observed between scaffold RD and clinical outcome scores, either preoperatively or postoperatively.
authors.affiliation: Department of Radiology, Ghent University Hospital, Belgium. tineke.deconinck@ugent.be
authors.forename: Tineke
authors.initials: T
authors.lastname: De Coninck
authors.forename: Wouter
authors.initials: W
authors.lastname: Huysse
authors.forename: Laurent
authors.initials: L
authors.lastname: Willemot
authors.forename: René
authors.initials: R
authors.lastname: Verdonk
authors.forename: Koenraad
authors.initials: K
authors.lastname: Verstraete
authors.forename: Peter
authors.initials: P
authors.lastname: Verdonk
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery*; D008875:Middle Aged; D011140:Polyurethanes / Q000627:therapeutic use; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D000070600:Tibial Meniscus Injuries; D054457:Tissue Scaffolds; D055815:Young Adult
chemical_list: D011140:Polyurethanes