Background: Studies on intramedullary nailing of humeral shaft
fractures in the orthopaedic literature have shown mixed results. The purpose
of this investigation was to document the clinical outcome and complications
associated with the use of a new flexible, locking intramedullary nail that
can be implanted in the humerus in either a retrograde or an antegrade manner
without violating the rotator cuff mechanism or damaging the articular surface
of the humeral head.
Methods: Fifty consecutive patients with fifty-one humeral shaft
fractures were entered into our prospective clinical outcome study. The
fracture was classified on the basis of the anatomic location and pattern.
Implant positioning and fracture alignment were assessed postoperatively.
Complications were recorded, and the time to union was measured. Shoulder
function was evaluated with use of a combination of the Constant shoulder
score, Short Form-36 (SF-36) clinical outcome data, range-of-motion
measurements, and a subjective pain-rating scale.
Results: Forty-one patients with forty-two fractures had an adequate
duration of clinical follow-up (a mean of twenty-two months) for analysis.
Thirty-nine fractures healed, with a mean time to clinical union of twelve
weeks (range, four to fifty weeks). Thirty-eight of the forty-two shoulders
had minimal or no pain. Thirty-six shoulders had a full range of motion. The
mean Constant shoulder score was 90 points. Four patients had five
complications, which included two nonunions, two hardware failures, and one
wound infection. All four patients had been managed with a 7.5-mm nail. A
multivariate analysis demonstrated that an age of more than fifty years was
associated with a lower Constant score and that the occurrence of a
complication was associated with a lower physical component score on the
Conclusions: The flexible humeral nail allows both retrograde and
antegrade implantation and static locking. Nail insertion can be accomplished
without violating the rotator cuff or damaging the articular surface of the
humeral head. Although the nail functioned well in most of our patients, the
use of a small-diameter (7.5-mm) nail was associated with a higher
complication rate. This implant should be used with caution in any patient
with a medullary canal diameter of =8 mm.
Level of Evidence: Therapeutic study, Level IV (case
series [no, or historical, control group]). See Instructions to Authors for a
complete description of levels of evidence.