LOCKING PLATES AND THE TREATMENT OF FRACTURES OF THE SURGICAL NECK OF THE HUMERUS

Background: The advent of locking plates used in the treatment of fractures of the surgical neck of the humerus has led to an increased use of internal fixation for these injuries. At present there are few large studies which have evaluated their success and potential factors which may contribute to any negative result. Materials and Methods: We retrospectively reviewed 57 consecutive patients who were treated with internal fixation of 2,3 and 4-part fractures of the proximal humerus over a 3 year period with a minimum follow-up of 6 months. The MacKenzie (antero-superior) approach was used in all cases and fixation was achieved using either the PHILOS or Arthrex locking plates. Patients were assessed by a thorough chart review and at regular post-operative clinics for pain, range of motion, return to work/activity, smoking and alcohol intake and overall compliance with rehabilitation regime. X-rays were graded on the quality of initial reduction and maintenance of position. Primary end-points included union of fracture and need for additional operative procedures. Results: The average age of patients was 63 years (range 19–91) with a preponderance of women (29:18 female: male). Average follow-up was 8 months. Ten (18%) patients were classified as problem drinkers, and 13 (22%) were smokers. Four patients were initially treated by a trial of conservative management which later failed, necessitating surgical intervention. Fifty three fractures (93%) went on to achieve union within 6 months of injury. Nine patients (15%) required an additional operation: 5 conversions to hemiarthroplasty for pain relief and 4 removals of metal for loss of screw fixation or impingement. There was no increased need for re-operation in alcoholics, but there was a 50% increase in the need for additional operations in smokers. Discussion: To our knowledge, this study represents the largest cohort of patients treated with a fixed-angle locking plate for a fracture of the surgical neck of humerus. The use of the locking plate has led to improved union rates and good functional outcomes in the treatment of these often problematic fractures. Although these fractures tend to occur more often in alcoholics, union rates and need for re-operation are not affected. Smoking is a significant a risk factor for the need for re-operation and non-union.