title: Transverse coronoid fracture: when does it have to be fixed?
abstract: BACKGROUND
  After elbow fracture-dislocation, surgeons confront numerous treatment options in pursuing a stable joint for early motion. The relative contributions of the radial head and coronoid, in combination, to elbow stability have not been defined fully.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the effect of an approximately 50% transverse coronoid fracture and fixation in the setting of an intact or resected radial head on coronal (varus/valgus) and axial (internal and external rotational) laxity in (1) gravity varus stress; and (2) gravity valgus stress models.
  
  
  METHODS
  Kinematic data were collected on six fresh-frozen cadaveric upper extremities tested with passive motion throughout the flexion arc under varus and valgus gravity stress with lateral collateral ligaments reconstructed. Testing included coronoid fracture and osteosynthesis with and without a radial head.
  
  
  RESULTS
  In the varus gravity stress model, fixation of the coronoid improved varus stability (fixed: 1.6° [95% confidence interval, 1.0-2.2], fractured: 5.6° [4.2-7.0], p < 0.001) and internal rotational stability (fixed: 1.8° [0.9-2.7], fractured: 5.4° [4.0-6.8], p < 0.001), but radial head fixation did not contribute to varus stability (intact head: 2.7° [1.3-4.1], resected head: 3.8° [2.3-5.3], p = 0.4) or rotational stability (intact: 2.7° [0.9-4.5], resected head: 3.9° [1.5-6.3], p = 0.4). With valgus stress, coronoid fixation improved valgus stability (fixed: 2.1° [1.0-3.1], fractured: 3.8° [1.8-5.8], p < 0.04) and external rotation stability (fixed: 0.8° [0.1-1.5], fractured: 2.1° [0.9-3.4], p < 0.04), but the radial head played a more important role in providing valgus stability (intact: 1.4° [0.8-2.0], resected head: 7.1° [3.5-10.7], p < 0.001).
  
  
  CONCLUSIONS
  Fixation of a 50% transverse coronoid fracture improves varus and internal rotatory laxity but is unlikely to meaningfully improve valgus or external rotation laxity. The radial head, on the other hand, is a stabilizer to resist valgus stress regardless of the status of the coronoid.
  
  
  CONCLUSIONS
  Determination as to whether it is necessary to fix a coronoid fracture should be based on the stability of the elbow when tested with a varus load. The elbow may potentially be stable with fractures involving less than 50% of the coronoid. Under all circumstances, the radial head should be fixed or replaced to ensure valgus external rotatory stability.
authors.affiliation: San Antonio Orthopaedic Group, 150 E. Sonterra Blvd Suite 300, San Antonio, TX, 78258, USA.
authors.forename: Robert U
authors.initials: RU
authors.lastname: Hartzler
authors.forename: Manuel
authors.initials: M
authors.lastname: Llusa-Perez
authors.forename: Scott P
authors.initials: SP
authors.lastname: Steinmann
authors.forename: Bernard F
authors.initials: BF
authors.lastname: Morrey
authors.forename: Joaquin
authors.initials: J
authors.lastname: Sanchez-Sotelo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000503:physiopathology / Q000601:surgery; D004551:Elbow Joint / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005592:Fracture Fixation; D006112:Gravitation; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D007593:Joint Instability / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011884:Radius / Q000293:injuries / Q000503:physiopathology / Q000601:surgery*; D011885:Radius Fractures / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular; D020127:Recovery of Function; D013314:Stress, Mechanical; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome; D000092464:Elbow Injuries