RADIAL HEAD FRACTURES Introduction Fractures of the head of the radius are relatively common. The injury can be subtle unless specifically looked for. It is far more common in adults than in children, (who more commonly fracture their neck of radius). Mechanism Fractures of the head of the radius will most commonly be as a result of a fall on the outstretched hand, with the force transmitted axially through the shaft of the radius to the radial head and capitellum. Classification The most commonly used classification is the Mason classification: 1 Type I: Non-displaced fractures of the radial head. Type II: Fractures of the radial head with displaced segments
Type III: Comminuted fractures of the radial head Essex-Lopresti fracture dislocation. With severe force fracture (usually comminuted) of the radial head may be associated with dislocation of the distal radioulnar joint may occur. This is the Essex-Lopresti fracture dislocation. This injury occurs as follows. With severe force: 1. The head of the radius fractures. 2. The articular surface of the capitellum is damaged. 3. The interosseous membrane tears. 4. Often the radial head fracture will be comminuted.
5. Subluxation of the distal end of the ulna occurs due to proximal migration of the radius. Complications Potential complications include: Damage to the capitellum, which will prolong recovery time. An Essex-Lopresti fracture dislocation, as described above. Joint stiffness is common and may involve both the elbow and radioulnar joint. Myositis ossificans Clinical Features On examination look for: 1. Swelling, pain, less commonly bruising over the region of the radial head. 2. In minor fractures tenderness may not be immediately apparent, unless carefully looked for. This is best done by direct pressure over the radial head, whilst rotating the forearm, both ways, (as shown below): 3. Check for tenderness over the radioulnar joint, (for a possible Essex-Lopresti fracture-dislocation)
Investigations Plain radiography Most radial head fractures can be diagnosed with standard lateral and (supinated) AP views. If standard views do not reveal a fracture, then further views should be taken if clinical suspicion remains high. Views should include, additional AP projections, in the mid prone and full prone positions. On occasions subtle non-displaced fractures may not be seen initially. Further views A positive fat pad sign may indicate occult fracture. Anterior fat pads are abnormal if lifted off the humerus, (a positive sail sign ) as below), a posterior fat pad if visualized is always abnormal One or both fat pad signs may be seen. The anterior sail sign is seen more commonly than the posterior fat pad sign. CT scan Anterior and posterior fat pads. See also example below in appendix 1 If no fracture is seen, but clinical suspicion remains high, (e.g. positive fat pad signs or significant symptoms), the patient should be treated symptomatically and then re x-rayed in 7 days time. Alternatively a CT scan may be done.
Management 1. Analgesia as indicated. 2. Type I fractures: Tubigrip and sling, for 2-3 weeks Physiotherapy referral. Type II fractures: These may need surgical fixation of significant fragments and should be referred to the orthopaedic unit. Type III fractures: These need referral to the orthopaedic unit. They may require surgical excision of the fragmented head and possibly later prosthetic replacement. Essex- Lopresti fracture-dislocation: These need referral to the orthopaedic unit.
Appendix 1 Occult type I radial head fracture: Radiographs of a 26 year old woman who sustained a fall onto her right outstretched hand. Fracture is not obvious, but is suspected by the presence of both posterior and anterior fat pad signs.
...Fracture of the head of the radius becomes obvious on a dedicated radial head view References 1. Mason, M.L. Some observations on fractures of the head of the Radius with a Review of 100 cases Br J Surg 42: 123-132, 1954 2. McRae R, Practical Fracture Management, 3 rd ed 1994, p.147-149. 3. Apley s System of Orthopedics and Fractures, 7 th ed 1993, p.585-585. 4. Wheelessonline Orthopedic Website: //www.wheelessonline.com/ Dr. J. Hayes. Reviewed February 2013