Anatomical and clinical study of a novel anterial cubital approach for ulnar coronoid fractures

Abstract

Listen

Translate article

Objective To investigate the feasibility of a noval anterior cubital approach for the coronoid via flexor-pronator teres interval and assess the clinical result. Methods Five formalin-fixed adult cadaver elbows were used. Through a single universal anteromedial longitudinal skin incision, the coronoid tip was exposed via pronator and flexor carpiradialis interval, and coronoid anteromedial facet and base via palm longus and flexor carpi ulnaris interval. The distances from the entry point to the muscles or branching point of the nerves to the line passing through medial and lateral epicondyles, as well as the length were measured with regard to the motor nerve branches arising from median nerve to pronator teres, flexor carpiradialis, palm longus and flexor digiti superficialis, as well as the most proximal two motor branches to flexor carpi ulnaris arising from ulnar nerve. From September 2013 to August 2014, 4 male patients with ulnar coronoid fracture were treated operatively through the above anterior cubital approach in our hospital. They were all left side involved, with an average age of 32 years (range, 16-42 years). According to O'Driscoll classification, there were two cases of type Ib and two cases IIb respectively. They were all treated by open reduction and internal fixation through flexor-pronator teres interval. Results At cubital fossa, there were 2-3 branches to the pronator teres mostly, 1 branch to flexor carpiradialis and palm longus arising from median nerve. The branch to the flexor digiti superficialis usually was long and thick, and divided into 2-5 short twigs near muscle. The branch to palm longus had the same trunk with that to flexor digiti superficialis. The branch to flexor digiti superficialis was the most proximal among those passed through the interval of pronator teres and flexor carpiradialis, and its entry point to the muscle had an averaged distance of 37.22 mm to the line passing through medial and lateral humeral epicondyles. It was optimal to expose coronoid tip through the interval of pronator teres and flexor carpiradialis. It was safe to expose coronoid proximal to the branch to flexor digiti superficialis. While, it was better to expose the anteromedial facet and base of corocoid through the interval of palm longus and flexor carpiulnaris via median and ulnar nerve interface. All of the four patients were followed up for an average period of 9 months. They all achieved bone union from 6 weeks to 3months (mean, 9 weeks). All the patients obtained excellent result according to the modified An & Morrey elbow performance index with scores from 94 to 100. Conclusion The novel anteromedial cubital approach via flexor-pronator teres is optimal for exposure of coronoid. Key words: Ulna; Fractures, bone; Fracture fixation, internal