- Anatomy of Olecranon:

- Radiology:
    - insist on a true lateral X-ray of the elbow joint to evaluate:
          - extent of frx & displacement:
                - non comminuted = displacement of less than 2 mm;
                - w/ flexion, frx displacement may be found to increase;
                - usually frx gaps dorsally, and some separation of fragments occurs, which leads to joint incongruity;
          - degree of comminution;
          - disruption of articlar surface in semilunar notch;
          - displacement of radial head
    - definition of displacement:
          - displacement of > 2 mm;
          - increase in degree of separation w/ 90 deg. flexion of the elbow;
          - inability to extend the elbow actively against gravity
    - Mayo classification
          - type I: (undisplaced fracture);
                - by definition is stable to flexion and extension and allows early mobilization in 3-5 days;
          - type II olecranon frx:
                - displaced, stable frx;
                - frx fragments are displaced > 2-3 mm, but collateral ligaments are intact;]
                - frx may be non-comminuted (Type IIA) or comminuted (Type IIB).
                - no sign of subluxation;
          - type III:
                - displaced fracture:
                - frx is displaced & forearm is unstable in relation to humerus;
                - this injury is really a fracture-dislocation.
   - misc:
          - coronoid process + olecranon frx;
          - patella buitis:
                - ocassionaly occurance of patella buitis, which is true accessory ossicle located in triceps tendon at its insertion into olecranon;
                - may be confused with a fracture

Olecranon stress fractures in throwers. A report of two cases and a review of the literature.