title: One-year clinical and MR imaging outcome after partial meniscal replacement in stabilized knees using a collagen meniscus implant.
abstract: OBJECTIVE
  The purpose of the study was to evaluate the clinical and radiological outcomes after medial/lateral collagen meniscus substitution (CMI) at 12 months postoperatively.
  
  
  METHODS
  Sixty-seven patients (m:f = 47:20, mean age 36 ± 10 years) underwent arthroscopic CMI after previous subtotal medial (n = 55) or lateral meniscectomy (n = 12) due to persistent joint line pain (n = 25) or to prophylactic reasons (n = 42). Clinical follow-up consisted of IKDC score, Tegner score, Lysholm score, and visual analog scale for pain and satisfaction (preinjury, preoperatively, and 12 months postoperatively; follow-up rate 90 %). MRI scans were analyzed according to the Genovese criteria.
  
  
  RESULTS
  Nineteen patients (29 %) showed a normal (A), 35 nearly normal (B), 5 abnormal (C), and 1 patient severely abnormal total IKDC score (D). The median Tegner preinjury score was 7 (range 2-10) and at follow-up 6 (range 2-10). The mean Lysholm score before surgery was 68 ± 20 and 93 ± 9 at follow-up. Preoperatively, the mean VAS pain was 4.4 ± 3.1 and 2.0 ± 1.0 at follow-up. Clinical failure of the CMI occurred in 3 patients (n = 1 infection, n = 1 failure of the implant, n = 1 chronic synovitis). On MRI, the CMI was completely resorbed in 3 patients (5 %), partially resorbed in 55 (92 %), and entirely preserved in 3 (5 %) patients. In 5 patients (8 %) the CMI was isointense, in 54 (90 %) slightly and 1 (2 %) highly hyperintense. 43 (72 %) patients showed an extrusion of the CMI implant of more than 3 mm.
  
  
  CONCLUSIONS
  Significant pain relief and functional improvement throughout all scores at 1 year was noted. The CMI undergoes significant remodeling, degradation, resorption, and extrusion in most of the patients. No difference in outcomes between the medial and lateral CMI was observed.
  
  
  METHODS
  Prospective therapeutic study, Level IV.
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Kantonsspital Bruderholz, 4101, Bruderholz, Switzerland. michael.hirschmann@ksbh.ch
authors.forename: M T
authors.initials: MT
authors.lastname: Hirschmann
authors.forename: L
authors.initials: L
authors.lastname: Keller
authors.forename: A
authors.initials: A
authors.lastname: Hirschmann
authors.forename: L
authors.initials: L
authors.lastname: Schenk
authors.forename: R
authors.initials: R
authors.lastname: Berbig
authors.forename: U
authors.initials: U
authors.lastname: Lüthi
authors.forename: F
authors.initials: F
authors.lastname: Amsler
authors.forename: N F
authors.initials: NF
authors.lastname: Friederich
authors.forename: M P
authors.initials: MP
authors.lastname: Arnold
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000601:surgery*; D001182:Arthroscopy; D003094:Collagen; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery*; D008875:Middle Aged; D019736:Prostheses and Implants; D016896:Treatment Outcome
chemical_list: D003094:Collagen