title: Relationship between markers of type II collagen metabolism and tibiofemoral joint space width changes after ACL injury and reconstruction.
abstract: BACKGROUND
  Those who suffer anterior cruciate ligament (ACL) disruptions are at increased risk of experiencing posttraumatic osteoarthritis (OA); however, by the time they become symptomatic, irreversible damage has likely occurred. Little is known regarding the physiological changes in articular cartilage that occur after an ACL injury and the onset of OA.
  
  
  OBJECTIVE
  To assess whether patient, functional, and clinical outcomes and type II collagen metabolism are associated with abnormal tibiofemoral joint space width (JSW) 4 years after injury and reconstruction.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A total of 35 ACL-injured patients who underwent ACL reconstruction were enrolled soon after injury, as were 32 matched controls. At baseline and 1- and 4-year follow-ups, patient-oriented subjective and objective outcomes and markers of type II collagen metabolism (considered as the ratio of cleavage to synthesis of type II collagen) were evaluated, as were radiographic measurements of JSW changes about the medial and lateral compartments of the knee. ACL-injured patients were divided into normal and abnormal JSW groups.
  
  
  RESULTS
  Both ACL-injured groups (normal and abnormal JSW) had an increased ratio of collagen type I and II cleavage product (uC1,2C) to serum procollagen II C-propeptide (sCPII) compared with controls at 1- and 4-year follow-ups. Patients in the ACL group with an abnormal JSW difference had significantly increased cleavage-to-synthesis ratios of type II collagen (assessed as C-terminal cross-linked telopeptide of type II collagen [uCTX-II]/sCPII ratio) compared with controls at 4-year follow-up. ACL-injured patients with an abnormal JSW difference had significantly increased pain and decreased quality of life (Knee Injury and Osteoarthritis Outcome Score [KOOS]) scores than did ACL-injured patients with a normal JSW difference.
  
  
  CONCLUSIONS
  ACL-injured patients with an abnormal tibiofemoral JSW had diminished quality of life, increased pain, and increased type II collagen uCTX-II/sCPII ratios compared with healthy controls. These changes occurred over an interval shortly after injury in patients who were fully functional and who had normal clinical examination findings, no pivoting/giving-way episodes, and no decrease in activity level.
authors: Department of Orthopaedics and Rehabilitation, University of Vermont College of Medicine, Burlington, VT 05405, USA.
authors: Timothy W
authors: TW
authors: Tourville
authors: Robert J
authors: RJ
authors: Johnson
authors: James R
authors: JR
authors: Slauterbeck
authors: Shelly
authors: S
authors: Naud
authors: Bruce D
authors: BD
authors: Beynnon
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D050376:Bone-Patellar Tendon-Bone Grafting / Q000534:rehabilitation*; D002358:Cartilage, Articular / Q000502:physiology*; D016022:Case-Control Studies; D024043:Collagen Type II / Q000378:metabolism*; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000378:metabolism / Q000534:rehabilitation / Q000601:surgery; D007719:Knee Joint / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D024043:Collagen Type II