title: A Surgical Model of Posttraumatic Osteoarthritis With Histological and Gait Validation.
abstract: BACKGROUND
  Posttraumatic osteoarthritis (PTOA) is secondary to an array of joint injuries. Animal models are useful tools for addressing the uniqueness of PTOA progression in each type of joint injury and developing strategies for PTOA prevention and treatment.
  
  
  OBJECTIVE
  Intra-articular fracture induces PTOA pathology.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Through a parapatellar incision, the medial tibial plateau was exposed in the left knees of 8 Sprague-Dawley rats. Osteotomy at the midpoint between the tibial crest and the outermost portion of the medial tibial plateau, including the covering articular cartilage, was performed using a surgical blade. The fractured medial tibial plateau was fixed with 2 needles transversely. The fractured knees were not immobilized. Before and after surgery, rat gait was recorded. Rats were sacrificed at week 8, and their knees were harvested for histology.
  
  
  RESULTS
  After intra-articular fracture, the affected limbs altered gait from baseline (week 0). In the first 2 weeks, the gait of the operated limbs featured a reduced paw print intensity and stride length but increased maximal contact and stance time. Reduction of maximal and mean print area and duty cycle (the percentage of stance phase in a step) was present from week 1 to week 5. Only print length was reduced in weeks 7 and 8. At week 8, histology of the operated knees demonstrated osteoarthritic pathology. The severity of the PTOA pathology did not correlate with the changes of print length at week 8.
  
  
  CONCLUSIONS
  Intra-articular fracture of the medial tibial plateau effectively induced PTOA in rat knees. During PTOA development, the injured limbs demonstrated characteristic gait.
  
  
  CONCLUSIONS
  Intra-articular fracture represents severe joint injury and associates with a high rate of PTOA. This animal model, with histologic and gait validations, can be useful for future studies of PTOA prevention and early diagnosis.
authors: Orthobiologic Laboratory, MedStar Union Memorial Hospital, Baltimore, Maryland, USA.
authors: Talal
authors: T
authors: Zahoor
authors: Orthobiologic Laboratory, MedStar Union Memorial Hospital, Baltimore, Maryland, USA.
authors: Reed
authors: R
authors: Mitchell
authors: Orthobiologic Laboratory, MedStar Union Memorial Hospital, Baltimore, Maryland, USA.
authors: Priya
authors: P
authors: Bhasin
authors: Orthobiologic Laboratory, MedStar Union Memorial Hospital, Baltimore, Maryland, USA.
authors: Lew
authors: L
authors: Schon
authors: Orthobiologic Laboratory, MedStar Union Memorial Hospital, Baltimore, Maryland, USA.
authors: Zijun
authors: Z
authors: Zhang
keywords: cartilage; fracture; gait; osteoarthritis; rats