Imaging of the elbow following trauma

New mechanism of the posterior elbow dislocation

PURPOSE

To suggest a new model on the most common kind of posterior elbow dislocation using MRI findings on acute elbow injuries.

METHODS

Fifteen patients with simple elbow dislocation (Group A) and 19 patients sustaining pure ligament injuries (Group B) were enrolled in this study. Using MRI scans, bony contusion at radial head and posterior capitellum (lateral bone contusion) and medial aspect of the ulnohumeral joint (medial bone contusion) were investigated with the injury patterns of the collateral ligament and overlying muscles. In Group A, the injury patterns of the ulnar and lateral ulnar collateral ligaments were classified into distraction or stripping type; in Group B, into rupture or strain. Based on these findings, we speculated the injury mechanism of the elbow dislocation.

RESULTS

In Group A, posterolateral (PL) dislocation was found in 12 cases of distractive ulnar collateral ligament type and stripping lateral ulnar collateral ligament type, where lateral bone contusion was found in 11 cases. Posteromedial (PM) dislocation was observed in only two cases of distraction type of the LUCL, where medial bone contusion was seen in two cases. In PL dislocation of the elbow joint, we always found more severe damage of soft tissue at the medial side of the elbow joint compared to the lateral side. Lateral bone contusion was speculated to be caused by bony abutment under pathologic forearm external rotation (PFER) and medial bone contusion, by bony abutment under varus stress. In Group B, the ulnar collateral ligament was more commonly injured than the lateral ulnar collateral ligament, and lateral bone contusion accompanied most cases.

CONCLUSION

PL dislocation is thought to start from the medial side in contrary to PM dislocation beginning at the lateral side. If the disengagement of the coronoid process is not completed due to the insufficient valgus/varus distraction, a coronoid fracture will develop at the same time as the elbow dislocation during PFER.

Surgical treatment of complex distal humeral fractures: functional outcome after internal fixation using precontoured anatomic plates

HYPOTHESIS

Several studies have shown good results with internal fixation of distal humeral fractures; however, few have focused specifically on anatomic parallel plate fixation using the same implant and postoperative regimen. The purpose of this study was to determine the functional outcome after open reduction and internal fixation of these complex fractures using parallel precontoured anatomic plates.

MATERIALS AND METHODS

This was a retrospective single-surgeon series involving 16 patients (12 women, 4 men) treated with a double-column parallel plating technique. Clinical assessment included the Mayo Elbow Performance Score (MEPS) and Disabilities of the Arm, Shoulder and Hand Score (DASH). Mean age was 43 years (range, 20-78 years). Average follow-up was 35 months. Four fractures were AO type A and 12 were AO type C.

RESULTS

Union was achieved in all patients. There was no superficial or deep infection or hardware failure. Two patients required removal of plates for pain and prominence but not all screws could be completely removed. The mean flexion was 132 degrees and extension was 29 degrees . The mean DASH score was 46.1. Grip strength was 56% of the uninjured side. Mean flexion and extension force was 72% and 70%, respectively, of the uninjured elbow. The mean MEPS score was 72.3.

DISCUSSION

Anatomically precontoured parallel plates are effective in achieving bony union with low implant failure with acceptable functional outcomes. However, screw extraction can be difficult when the implant is removed.

Distal humerus fractures

Intra-articular fractures of the distal humerus are among the most challenging fractures to manage. Nonoperative treatment, although appropriate for some patients, often leads to loss of motion and unsatisfactory functional outcomes. Over the last 2 decades, enhanced operative techniques and implant designs have improved the reduction and stability of distal humerus fractures leading to better outcomes. Careful preoperative planning, adequate exposure, and stable fixation facilitating early mobilization are essential to achieve successful outcomes with internal fixation.