title: Tissue-engineered collagen meniscus implants: 5- to 6-year feasibility study results.
abstract: OBJECTIVE
  In this feasibility study, a 5- to 6-year clinical follow-up evaluation was conducted on 8 patients who had undergone reconstruction of 1 injured medial meniscus with a tissue-engineered collagen meniscus implant. The hypothesis was that these patients would show significant clinical improvement over their preoperative status and would have maintained their status determined at the 2-year follow-up evaluation.
  
  
  METHODS
  Prospective longitudinal feasibility study follow-up evaluation.
  
  
  METHODS
  Eight patients underwent arthroscopic placement of a collagen meniscus implant by a single surgeon to reconstruct and restore the irreparably damaged medial meniscus of 1 knee. All patients returned for clinical, radiographic, magnetic resonance imaging, and arthroscopic examinations an average of 5.8 years (range, 5.5-6.3 y) after collagen meniscus implant placement.
  
  
  RESULTS
  Lysholm scores improved significantly (P = .045) from 75 preoperatively to 88 at most recent follow-up evaluation. Average Tegner activity scores improved significantly (P = .001) from 3 to 6. Patient self-assessment improved significantly (P = .046) from 2.4 to 1.9 (1 = normal, 4 = severely abnormal). Pain scores improved from 23 to 11 (0 = no pain, 100 = worst pain). Imaging studies confirmed that the chondral surfaces of the medial compartment had not degenerated further since the placement of the implant 5.8 years earlier. Relook arthroscopy with direct measurement of the newly generated tissue revealed 69% defect filling. Histologic assessment of tissue biopsy specimens from 3 patients showed the presence of fibrocartilage with a uniform extracellular matrix.
  
  
  CONCLUSIONS
  The meniscus-like tissue that developed after collagen meniscus implant placement has maintained its structure and functioned without negative effects for more than 5 years. The hypothesis was affirmed that these patients were improved significantly compared with their preoperative status and unchanged compared with 2-year evaluations.
  
  
  METHODS
  Level IV.
authors.affiliation: Steadman Hawkins Clinic, Vail, Colorado, USA.
authors.forename: J Richard
authors.initials: JR
authors.lastname: Steadman
authors.forename: William G
authors.initials: WG
authors.lastname: Rodkey
mesh_terms: D000328:Adult; D003094:Collagen; D005240:Feasibility Studies; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008592:Menisci, Tibial / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain; D019736:Prostheses and Implants; D011859:Radiography; D012038:Regeneration; D013997:Time Factors; D023822:Tissue Engineering; D016896:Treatment Outcome
chemical_list: D003094:Collagen