The coracoid process plays an essential role in the stability of the elbow joint due to its unique anatomical features. Coronary process fracture is a sort of intra-articular fracture, and although it is uncommon, its injury is often accompanied by the dislocation of the elbow joint and ligament damage. Improper treatment will produce adverse impacts on its functional restoration. Coracoid process fracture has become a core issue of elbow trauma and instability. Surgical treatment for fracture reduction, fixation, and ligament repair is essential to restore good elbow function.In recent years, medial and lateral approaches have been reported in the literatures regarding surgical approaches. However, a generally accepted method has not been discovered. Reichel et al. described an anterior approach through the space between the biceps and the medial bicipital neurovascular bundle, but the branches of the brachial artery did interfere with the exposure of surgical field and the operation as well. The brachial blood vessels and median nerve are separated between the capitellum and the capitulum ulnae of the pronator teres, and through this space, it is less likely to damage the vascular and nerve bundles.

Ⅰ. General information.From January 2014 to January 2016, 15 patients with coronoid process fractures were selected as the study subjects (9 males and 6 females; aged 17-65 years with an average of 32 years) in the Department of orthopedics of Shanghai Zhongye Hospital. All patients were closed unilateral fractures. According to Regan-Morrey classification, there were 10 cases of type II and 5 cases of type III. No osteofascial compartment syndrome was discovered and all the patients received surgery 3 to 7 days after the initial injury (averaged 5.3 days) . This study has been approved by the Hospital Medical Research Ethics Committee, and has obtained consent and signed consent from the participants.Ⅱ. Inclusive and exclusive criteria.Inclusion criteria: (1) age of ≥17 years; (2) fresh closed fractures; (3) without vascular and nerve injury; (4) excellent elbow joint function score before injury; (5) with anteroposterior and lateral views of X-ray films and 3D CT reconstruction of the elbow joint and diagnosis of coronoid process fracture; (6) with surgical treatment indications. Exclusion criteria: (1) age of<17 years; (2) pathological fractures; (3) open fractures; (4) history of elbow joint trauma or surgery; (5) patients combined with severe physical and mental disorders; (6) patients combined with radial head fractures.Ⅲ.Operative methods. 1. Preoperative preparation: All patients underwent preoperative detumescence treatment. Approximately 5 days after the injury, the soft tissue condition of the elbow joint was suitable for surgical treatment. X-ray and CT examinations were performed before operation, and the fracture type was determined for appropriate fixation method, mainly the mini-plate. The collateral ligament was repaired with anchors for those with collateral lateral ligament injury. The preoperative examination was conducted to exclude surgical contraindications. Antibiotics were used once to prevent infection before surgery. 2. Surgical procedure: Under general anesthesia or brachial plexus block anesthesia, the patient was placed in the supine position. The S-shaped incision was made at 2 cm above the inside of the elbow flexion crease. Through the crease, the incision extended distally along the radial side of the forearm to approximately 4 cm beyond the flexion crease. The important veins were protected without removing the cephalic vein, Rosenthal's vein and median cubital vein, and the medial cutaneous nerve of the forearm was exposed after blunt subcutaneous dissection. The deep fascia, biceps brachii, biceps brachii insertion, and distal lateral pronator was exposed as well. The bicipital aponeurosis was longitudinally separated to expose the arteries and veins and nerves of the proximal humerus. Extending distally from the space between the anterior pronator and the humeral head, the brachioradialis and the distal end of pronator was separated and exposed. Due to the loosen structure and absence of neurovascular branch, there was a certain gap between the radial artery and the ulnar nerve. To fully expose the brachialis, the brachial artery, biceps brachii and brachioradialis were pulled toward the radial side, while the medial nerves and pronator were pulled toward the ulnar side. The fracture fragments and basal part of coronoid process were fully exposed. Under direct vision, the fracture was anatomically reduced and fixed with a mini-plate. Two patients presented with lateral instability of the elbow joint.Ⅳ. Perioperative management. Indomethacin was given before and after surgery to prevent heterotopic ossification (HO) . The patients received anti-inflammation and detumescence with a local cold compress for 3-5 days after the operation. The stability of the fracture end and elbow joint was observed during operation. For those with good fixation effect, the forearm was flexed in 90° with sling protection. The active flexion and extension of the elbow joint started after 2 to 3 days. For those with poor fixation in the operation, the elbow joint was fixed at 90° of flexion with plaster. The passive exercise was initiated until the active flexion and extension of the elbow joint were restored as soon as possible. Regular follow-ups were performed 4 weeks, 12 weeks, 6 months, and 12 months after surgery.Ⅴ. Observational index.The operation time, intraoperative blood loss, and complications were recorded. The efficacy was evaluated according to the Mayo elbow joint function score.Ⅵ. Statistical analysis.SPSS 19.0 software was used for statistical analysis. The data were expressed as mean ± standard deviation. The statistical significance of each group was evaluated by a 2-tailed t-test. A value of P<0.05 was considered the statistical difference.

All surgeries were successfully completed without vascular damage. All fractures were anatomically reduced and rigidly fixed. The average follow-up period was 23 months (12 - 36 months) . The fracture healing time averaged 15 weeks (13-18 weeks) . All incisions healed well without deep infections or swelling of the forearms. In the last follow-up, the flexion and extension of the elbow was (137±14) °, and the forearm pronation/supination was restored to (127±13) °. According to the functional evaluation system of the coronoid process, 14 cases were excellent, and 1 case was good. According to the Mayo elbow function score, the functional assessment results averaged 94.8 points (84-98 points) . There was no significant difference in the recovery of elbow joint function between the affected side and the healthy side (P>0.05) . One patient with mild myositis ossificans, and recovered after postoperative functional rehabilitation. No other complications such as elbow dislocation, subluxation, traumatic arthritis, etc. occurred. All patients resumed their previous work during the final follow-up.

The antecubital brachial artery and median nerve space approach combined with mini-plate fixation in the treatment of coronary process fracture is simple, safe and minimal trauma with high exposure rate and satisfactory prognosis.