title: N-terminal telopeptides of type I collagen and bone mineral density for early diagnosis of nonunion: An experimental study in rabbits.
abstract: BACKGROUND
  The diagnosis and treatment of bone nonunion have been studied extensively. Diagnosis and treatment of nonunion are mainly performed based on the interpretation of clinico-radiographic findings, which depend on the clinician's experience and the degree of bone callus formation during the fracture-healing process. However, resolution may be compromised when the bone mineral content is <25%. A feasible method of monitoring bone-healing is therefore needed. We monitored a rabbit model of bone nonunion by regular radiographic examinations, QCT detection, and biomarker concentrations.
  
  
  METHODS
  Twenty purebred New Zealand rabbits (10 male and 10 female, 5-6 months of age, 2.5-3.0 kg) were divided into bone defect Group (I) that 10 left radius bones underwent resection of 1.5 cm of mid-radius bone and bone fracture Group (II) that another 10 left radius bones underwent only mid-radius fracture. Quantitative computed tomography detection of bone mineral density (BMD) and serum markers of bone formation (osteocalcin [OC], bone-specific alkaline phosphatase) and bone resorption (C- and N-terminal telopeptides of type I collagen (NTX) and tartrate-resistant acid phosphatase 5b) were assayed. There are twenty rabbits (10 male and 10 females). The age was 5-6 months weighing 2.5-3.0 kg). The defect was created in middle 1/3 radius in 10 rabbits and fracture was created in middle 1/3 radius of 10 rabbits.
  
  
  RESULTS
  BMD and NTX concentrations were significantly lower at 5 weeks postoperatively compared to the preoperative values and were significantly different between the two groups. OC showed no significant difference before and after surgery.
  
  
  CONCLUSIONS
  BMD and NTX concentrations may be useful for early detection of bone nonunion in rabbits.
authors: Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China; Department of Orthopedic Surgery, Hainan Provincial People's Hospital, Haikou 570311, Hainan Province, China.
authors: Jian-Ping
authors: JP
authors: Lin
authors: Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China.
authors: Zhan-Jun
authors: ZJ
authors: Shi
authors: Department of Orthopedic Surgery, Hainan Provincial People's Hospital, Haikou 570311, Hainan Province, China.
authors: Ning-Jiang
authors: NJ
authors: Shen
authors: Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China.
authors: Jian
authors: J
authors: Wang
authors: Department of Orthopedic Surgery, Hainan Provincial People's Hospital, Haikou 570311, Hainan Province, China.
authors: Zao-Min
authors: ZM
authors: Li
authors: Department of Orthopedic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China.
authors: Jun
authors: J
authors: Xiao
keywords: Biomarkers; N-terminal telopeptide of type I collagen; Osteoporosis; biomarkers; bone fractures; bone mineral density; bone-specific alkaline phosphatase; nonunion; tartrate-resistant acid phosphatase 5b