[Treatment of anteromedial coronoid facet fractures with open reduction and internal fixation through anteromedial approach].

OBJECTIVE: To investigate the approach of open reduction and internal fixation for the treatment of anteromedial coronoid facet fractures and associated injury.

METHODS: From July 2009 to August 2011, 6 coronoid anteromedial facet fractures were treated (4 males and 2 females,the average age was 32.6 years old,ranged from 19 to 49 years old) in our hospital. Three patients had fractures in the left side and 3 in the right(4 dominant sides and 2 non dominant sides). All the patients had close fractures. All the fractures were subtype 2 or subtype 3 of coronoid anteromedial facet fracture according to O'Driscoll classification. The anteromedial incision of elbow and the approach of splitting flexor digitorum superficialis between flexor carpi radialis and palmaris longus were used to apply internal fixation with mini-plate. After fixation of coronoid fracture, widening of radiohumeral joint interspace under varus stress occurred in 3 cases,elbow varus posteromedial rotational instability was showed,and the exploration and repair of radial collateral ligament was not carried out. Plaster was applied for 2 weeks before rehabilitation and the time of plaster application extended to 4 weeks in the patients showed varus posteromedial rotational instability. The motion degree,pain and stability, strength of elbow and hand were recorded,the elbows were evaluated with modified An and Morrey functional rating index.

RESULTS: All the patients were followed up,and the average duration was 9.3 months (ranged from 7.5 to 13 months). The strength of elbow and hand were equal to that in the contralateral side. The average flexion was (129.0+/-6.5) degree (ranged from 120 to 135 degree); the average extention was (4.0+/-4.2) degree (ranged from 0 to 10 degree); the average forearm pronation was (84.0+/-6.5) degree (ranged from 75 to 90 degree); average supination was (89.0+/-7.1) degree (ranged from 80 to 100 degree). One patient had ulnar sensory neuropathy after operation and healed in half-year, no postoperative complications as pain and instability accured. All the patients obtained excellent results according to modified An and Morrey functional rating index.

CONCLUSION: The approach of splitting flexor digitorum superficialis between flexor carpi radialis and palmaris longus could be used in open reduction and internal fixation of anteromedial coronoid facet farcture, rehabilitation should be postponed in the patient showed elbow varus posteromedial rotational instability.