The pronator teres and the flexor carpi radialis interval approach for operative fixation of ulna coronoid process fractures

Background: The optimal approach for the fixation of coronoid process fractures is unknown. We present the advantages and the clinical effect of the pronator teres and the flexor carpi radialis interval approach for the treatment of ulna coronoid process fractures.

Methods: The patients, who had operative treatment of closed ulna coronoid process fracture by the pronator teres and the flexor carpi radialis interval approach between January 2011 to December 2016, were studied retrospectively. Seventeen consecutive patients had received surgical fixation by screws or a mini-plate through the above approach, of whom were 16 males and one female with an average age of 36.7 years (range, 21-58 years). There were 11 cases of type II and 6 cases of type III according to the O'Driscoll classification, of which, 6 patients had combined elbow dislocation, 2 patients showed elbow instability after fixation, and one had another incision to repair the lateral collateral ligament, and received a hinged external fixator. The other patient only received a hinged external fixator for 4 weeks. Mayo Elbow Performance Score (MEPS) was used to assess the function of elbow for each patient at the final follow-up.

Results: Mean follow-up was 28.7 months (range, 24-38 months). Fracture union was achieved in each patient; the average time to radiologic union was 14.2 weeks (range, 12-16 weeks). At the final follow-up, the elbow extension degree of the affected side was (3.88±2.96°), reaching 98.1% of the normal side, and the flexion degree was (131.59±4.93°), reaching 98.16% of the normal side. The forearm pronation was (82.94±3.86°), reaching 94.31% of the normal side, and the supination activity was (82.12±3.82°), reaching 93% of the normal side. According to the MEPS, the functional recovery of the injured arm was assessed as excellent in 16 cases, and good in one. None of the patients showed any neurovascular or deep infections and no heterotopic ossification was found.

Conclusions: The pronator teres and the flexor carpi radialis interval approach has the advantages of simplicity, safety, minimal invasion, excellent exposure, and good postoperative function recovery for ulna coronoid process fracture.