title: Age dependent changes of the facet joint alignment for cervical disc replacement: A radiographic evaluation.
abstract: BACKGROUND
  Artificial cervical disc implants are meant to last for several decades and therefore it is of interest, how the cervical facet joints undergo physiological changes over the course of years.
  
  
  OBJECTIVE
  The primary purpose of this study is to investigate an age dependent deformation in human cervical facet joints.
  
  
  METHODS
  The motion segments C2 to Th1 were measured in the cervical X-rays of 131 patients, aged between 14 and 88 years. The cranial and caudal facet joint angles were determined for each segment. The linear regression between the facet joint angle and age was determined. Furthermore the average as well as the standard deviation of the facet joint angle was determined for two groups, one group aged up to 57 years and the other group from 58 years upwards. The results were compared by means of the t-test.
  
  
  RESULTS
  The angles of the cranial facet joint surfaces C3-C7 ranged from 54° to 64°, those of the caudal facet joint surfaces C3-C7 from 52° to 58°. The alignment of both, the cranial and the caudal facet joint surfaces flattened with increasing age. The group with the older patients had significant lower facet joint angles than the group with the younger patients.
  
  
  CONCLUSIONS
  In conclusion, it should be taken into consideration, how the design of an artificial cervical disc needs to be adapted for a vertebral segment depending on the facet joint angle. Thus the articulation of a cervical motion segment can be optimized, so that it moves within a normal physiological manner.
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich, München, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: von Schulze Pellengahr
authors.affiliation: Ruhr-University Bochum, Bochum, Germany.
authors.forename: Ole
authors.initials: O
authors.lastname: Ackermann
authors.affiliation: Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich, München, Germany.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Müller
authors.affiliation: Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Teske
authors.affiliation: Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lahner
authors.affiliation: Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Ammar
authors.initials: A
authors.lastname: Scheib
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001178:Arthroplasty / Q000379:methods*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D059145:Total Disc Replacement / Q000379:methods*; D055815:Young Adult; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging* / Q000601:surgery*
keywords: Cervical facet joint; age; angle; cervical disc arthroplasty; disc prosthesis