Radius and ulna Flashcards
How much of the proximal thoracic limb weight bearing forces is carried by the proximal radial articular surface at the level of the elbow?
51%
At what level doe the interosseous ligament terminate?
Midshaft of the antebrachium
How much ulnar growth is the distal ulnar physis responsible for?
100%
How much do the proximal and distal radial physes contribute to growth?
Approximately 50/50
Describe the bony anatomy of the radius and ulna
Describe the important ligamentous structures of the elbow
What is the normal angle of procurvatum for the radius?
27 degrees
How do you calculate procurvatum of the radius?
⦰ + (90 - aCdPRA) + (90 = aCdDRA)
What are the normal joint orientation angles for the canine radial anatomic axes?
What degree of radial shortening can be detected on radiographs and CT respectively?
Radiographs: 1.5 - 4mm
CT: 1mm
Arthroscopy may be better than both of these modalities for assessment of radial shortening.
What are surgical options for radial lengthening in the juvenile patient?
Dynamic elongation generally preferred as they allow some adjustability as the dog continues to grow. Can include transverse osteotomy and placement of pins with elastic material to apply traction force, ESF with threaded connecting bar (Stader apparatus) and distraction osteogenesis.
What are surgical options for radial lengthening in the adult patient?
Either dynamic or acute elongation techniques can be considered. Acute elongation techniques include osteotomy and stabilization, or sagittal sliding osteotomy.
What is the alternative to radial lengthening techniques for treatment of short radius?
Shortening of the ulnar by ulnar ostectomy. May be preferable in adult patients as juvenile patients may heal prior to cessation of ulnar growth.
What is postulated to be the reason for the frequent injury of the distal ulnar physis?
Conical shape converts loading in any direction to compressive injury
What changes are frequently seen in the radius following premature closure of the distal ulnar physis?
Shortening, procurvatum, distal valgus, torsion.
In an immature patient with premature closure of the distal ulnar physis is an ulnar osteotomy or ostectomy procedure preferred?
Ostectomy, as it helps to prevent closure prior to cessation of radial growth.
What are the methods to prevent craniocaudal tipping of a proximal ulnar ostectomy?
Intramedullary pinning, bioblique osteotomy (proximocaudal-distocranial)
What is the benefit of a distal over proximal ulnar ostectomy for treatment of premature closure of the distal ulnar physis?
Distal location prevents tipping of the ulnar with pull of the triceps due to stabilization by the intraosseous ligament. Comparative efficacy of low versus high ulnar ostectomies remains unknown, however.
List 3 methods to prevent premature closure of a distal over proximal ulnar ostectomy for treatment of premature closure of the distal ulnar physis?
- Creation of an ostectomy gap 1.5 times the diameter of bone (Key’s hypothesis).
- Removal of all periosteum in the vicinity of the ostectomy.
- Insertion of a fat graft.