A particular pattern of complex instability of the elbow is “the terrible triad”, in which elbow dislocation is associated with fractures of the coronoid and radial head. Other frequent patterns are the variant of Monteggia lesions (Bado II) described by Jupiter which is characterized by ulnar fracture associated with fracture-dislocation of proximal radius, and the articular fracture of the distal humerus associated with elbow dislocation. The goal of treatment is to restore the primary stabilizers of the elbow such as the coronoid process, olecranon and both collateral ligaments by internal fixation and reconstruction of the ligaments. If elbow stability obtained at operation is unsatisfactory or internal fixation not enough stable, there an indication for applying a dynamic external fixator (DEF). The latter allows:

the articular congruence to be maintained and the ligaments to heal in adequate tension and position,

From 2005 to 2008, we treated surgically 31 patients with complex instability of the elbow. DEF was applied in 38% of cases, namely 3 terrible triads, 5 fracture-dislocations of Monteggia and 4 articular fractures of the humerus associated with elbow dislocation. The mean age of patients was 44 years (range 30–74). All patients underwent ORIF, reconstruction of ligaments and dynamic external fixation. The OptiROM elbow fixator was used In 2 patients, the Orthofix fixator in 1 and the DJD fixator in 9. In all cases, active elbow motion was allowed without restrictions from the second postoperative day. Indomethacin was consistently administered for 5 weeks to prevent heterotopic ossifications. The DEF was removed after 6 weeks. The mean follow-up was 25 months (range 5–44 months). At last follow-up, the clinical results, evaluated according to the MEPS, were excellent in 10 patients (83%), who had had a fast recovery of range of motion (ROM). The elbow was painless in all patients and stable in all but 1. Moderate osteoarthrosis was found in 60% of cases. Complications included: 1 elbow stiffness, 1 pseudarthrosis of capitulum humeri and trochlea, 1 transitory radial nerve palsy, and 1 superficial pin tract infection.

In conclusion, DEF is a helpful tool for treatment of complex elbow instability, particularly when stable internal fixation cannot be obtained or instability persists after ligaments reconstruction. However, DEF increases morbidity, and implies a longer operative time and prolonged exposure to radiation.

Purpose: Treatment of radial head fractures of Mason Type II and III involving the neck of the radius is still controversial, especially in the presence of comminution. ORIF often gives unsatisfactory results because of the difficulty in restoring the head-neck off-set and the radial head inclination relative to its neck. In these cases radial head replacement may be indicated ; however, there are no long-term studies on complications and survival of the implant. Recently precontoured plates for the proximal radius has been introduced but no trials have determined whether they are able to restore the normal anatomy of the radius. The latter is still partially unknown because no studies have analyzed the morphology of posterolateral aspect of radial head and neck (“safe zone”). Our study was aimed at:

determining the possible presence of anatomical variations of the safe-zone and

Material and Methods: Measurements, performed on 44 cadaver dry radii of adults, included: length of the radius, diameters and height of the radial head, and height and diameter of the neck of the radius. The radius of bending of the safe zone was also calculated.

Results: The morphological evaluation of the “safe zone” of the radius revealed 3 different morphological types of this zone:

(flat) (25 %),

Adherence of a precoundered plate (Acumed) to the bone surface of the safe zone was performed independently by three of us, and the gap between plate and bone was measured. Plate adaptability was good in Type B, scarce in Type C and absent in Type A.

Conclusion: In conclusion, we identified 3 different morphologies of the safe zone, not previously described, and we found that the precountered plates now available can ensure a good restoration of anatomy only in the half of the human radii.