Locking Plate for Proximal Humeral Fracture in the Elderly Population: Serial Change of Neck Shaft Angle

BACKGROUND We conducted this radiographic study in the elderly population with proximal humeral fracture aiming to evaluate 1) the serial changes of neck-shaft angle after locking plate fixation and 2) find relationship between change in neck shaft angle and various factors such as age, fracture pattern, severity of osteoporosis, medial support and initial reduction angle. METHODS Twenty-five patients who underwent surgical treatment for proximal humeral fracture with locking plate between September 2008 and August 2010 are included. True anteroposterior and axillary lateral radiographs were made postoperatively and at each follow-up visit. Measurement of neck shaft angle was done at immediate postoperative, 3 months postoperative and a final follow-up (average, 11 months; range, 8 to 17 months). Severity of osteoporosis was assessed using cortical thickness suggested by Tingart et al. RESULTS The mean neck shaft angles were 133.6° (range, 100° to 116°) at immediate postoperative, 129.8° (range, 99° to 150°) at 3 months postoperative and 128.4° (range, 97° to 145°) at final follow-up. The mean loss in the neck-shaft angle in the first 3 months was 3.8° as compared to 1.3° in the period between 3 months and final follow-up. This was statistically significant (p = 0.002), indicating that most of the fall in neck shaft angle occurs in the first three months after surgery. Relationship between neck shaft angle change and age (p = 0.29), fracture pattern (p = 0.41), cortical thickness (p = 0.21), medial support (p = 0.63) and initial reduction accuracy (p = 0.65) are not statistically significant. CONCLUSIONS The proximal humerus locking plate maintains reliable radiographic results even in the elderly population with proximal humerus fracture.