title: The effect of lunate morphology in Kienböck disease.
abstract: OBJECTIVE
  To determine if the absence (type I lunate) or presence (type II lunate) of a medial hamate facet on the lunate affects the radiographic characteristics of patients presenting with Kienböck disease.
  
  
  METHODS
  A retrospective review was performed on all patients evaluated at our institution from 2002 to 2010 with a diagnosis of Kienböck disease confirmed on plain radiographs in concert with magnetic resonance imaging (MRI) and/or bone scan. Study groups consisted of patients with type I versus type II lunates, as determined by radiographs, MRI, and/or computed tomography. Measured variables included the modified Lichtman stage on presentation, radioscaphoid angle, presence or absence of a coronal plane fracture of the lunate, modified carpal height, ulnar variance, and ulnar translocation of the carpus at the time of presentation.
  
  
  RESULTS
  A total of 106 wrists were examined, of which 75 were type I (71%) and 31 were type II (29%) lunates. At the time of presentation, there was significantly more advanced disease (stage IIIA or greater) in patients with type I (N = 64, 86%) compared with those with type II lunates (N = 19, 61%). Coronal fractures of the lunate were more prevalent in patients with type I (N = 58, 75%) compared with type II lunates (N = 18, 58%). In the absence of a coronal fracture, radioscaphoid angles were greater in patients with a type I (53°) versus a type II lunate (45°).
  
  
  CONCLUSIONS
  Lunate morphology may affect the severity of Kienböck disease at the time of initial presentation. Type II lunates appear to be protective against coronal fractures and scaphoid flexion deformities. This study provides further evidence that lunate morphology affects carpal pathology and may have implications for treatment options in Kienböck disease.
  
  
  METHODS
  Prognostic III.
authors.affiliation: Department of Orthopedic Surgery, San Antonio Military Medical Center, San Antonio, TX; Orthopedic Institute, Sioux Falls, SD; Division of Hand Surgery, Mayo Clinic, Rochester, MN; Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Division of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Rhee
authors.affiliation: Department of Orthopedic Surgery, San Antonio Military Medical Center, San Antonio, TX; Orthopedic Institute, Sioux Falls, SD; Division of Hand Surgery, Mayo Clinic, Rochester, MN; Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Division of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
authors.forename: David B
authors.initials: DB
authors.lastname: Jones
authors.affiliation: Department of Orthopedic Surgery, San Antonio Military Medical Center, San Antonio, TX; Orthopedic Institute, Sioux Falls, SD; Division of Hand Surgery, Mayo Clinic, Rochester, MN; Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Division of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Moran
authors.affiliation: Department of Orthopedic Surgery, San Antonio Military Medical Center, San Antonio, TX; Orthopedic Institute, Sioux Falls, SD; Division of Hand Surgery, Mayo Clinic, Rochester, MN; Division of Plastic Surgery, Mayo Clinic, Rochester, MN; Division of Orthopedic Surgery, Mayo Clinic, Rochester, MN. Electronic address: shin.alexander@mayo.edu.
authors.forename: Alexander Y
authors.initials: AY
authors.lastname: Shin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002348:Carpal Bones / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D012667:Lunate Bone / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000145:classification / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies; D014955:Wrist Joint / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Kienböck disease; lunate coronal plane fracture; lunate morphology; radioscaphoid angle; scaphoid flexion deformity