Osteoporosis does not affect bone mineral density change in the proximal humerus or the functional outcome after open reduction and internal fixation of unilateral displaced 3- or 4-part fractures at 12-month follow-up

Abstract

Background: The aim of this prospective study was to investigate bone mineral density (BMD) changes in the proximal humerus of the shoulder during a healing period of 12 months after displaced 3- or 4-part proximal humerus fractures treated with open reduction and internal fixation (ORIF) with an anatomic angular stable locking plate and the influence on fracture healing and functional outcomes.

Methods: In a prospective multicenter study, 36 patients (29F and 7M, age range: 38-83) with unilateral displaced 3- or 4-part proximal humerus fractures were included for ORIF. Dual-energy x-ray absorptiometry for osteoporosis status was employed. Postoperative and 6-week, 3-, 6-, and 12-month shoulder radiographs and dual-energy x-ray absorptiometry of the shoulder with BMD measures in 4 templated regions of interest (ROIs) were performed. Functional outcomes, Western Ontario Osteoarthritis of the Shoulder index, Constant score, visual analog scale pain (VAS), and 36-Item Short Form Survey, were collected.

Results: A total of 17 of 36 patients had osteoporosis. We found no differences in BMD changes, functional outcomes, radiology, or need for revision surgery between the osteoporosis and nonosteoporosis groups. The BMD values gradually declined from baseline to 3-month follow-up in all 4 ROIs of the operated shoulders. All 4 ROIs in the operated shoulder presented with a reduction in BMD at 3, 6, and 12 months compared with baseline, whereas no significant BMD changes were seen in the healthy shoulder during the study period. The functional outcomes displayed an increase in Constant score from 3 to 12 months, but a decrease in domains of the 36-Item Short Form Survey from preinjury to 12 months (physical functioning, general health, and bodily pain). Preinjury and 12-month Western Ontario Osteoarthritis of the Shoulder index, VAS pain at rest, and VAS pain at activity were comparable.

Conclusion: BMD changes appeared swiftly in the proximal humerus, after the treatment of displaced 3- or 4-part fractures with ORIF, particularly affecting the proximal diaphysis of the humerus. Shoulder function was restored to preinjury levels for most of the patients. Osteoporosis may not be regarded as a contraindication for the treatment of displaced 3- or 4-part fractures with ORIF.

Keywords: Proximal humerus fracture; angle stable locking plate; bone mineral density; disuse osteopenia; disuse osteoporosis; functional outcomes.