The Journal of Bone and Joint Surgery (American) 85:2403-2409 (2003)
© 2003 The Journal of Bone and Joint Surgery, Inc.
Forearm and Elbow Injury: The Influence of Rotational Position
Joseph C. McGinley, MS1,
Brendon C. Hopgood, MD2,
John P. Gaughan, PhD1,
Keyanoush Sadeghipour, PhD1 and
Scott H. Kozin, MD3
1 School of Medicine (J.C.McG.), Department of Biostatistics (J.P.G.), and
College of Engineering (K.S.), Temple University, 3400 North Broad Street,
Philadelphia, PA 19140
2 Department of Surgery, Albert Einstein Medical Center, 5501 Old York Road,
Philadelphia, PA 19141
3 Shriners Hospital for Children, Pediatric Hand and Upper Extremity Surgery,
3551 North Broad Street, Philadelphia, PA 19140. E-mail address:
skozin{at}shrinenet.org
Investigation performed at Temple University, Philadelphia,
Pennsylvania
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. They did not receive payments or
other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.
Background: The purpose of this study was to develop an axial
loading forearm fracture model and to determine the influence of forearm
rotation on the fracture pattern.
Methods: Twenty-six cadaveric arms were thawed in saline solution.
Pressure-sensitive film was sealed and was placed through a lateral arthrotomy
into the radiocapitellar joint. The arm was potted at the proximal part of the
humerus with the elbow in extension. Rotational range of motion was measured
with use of a goniometer starting from a supinated position (0°).
Specimens were placed in a vertical position at various angles of forearm
rotation, and a 27-kg mass was raised to 90 cm and was dropped onto the distal
part of the radius. The pressure film was removed and was analyzed to
determine the radiocapitellar joint contact area following impact. Each arm
was dissected, and the injury pattern was assessed.
Results: Both-bone forearm fractures (proximal radial fractures with
concomitant distal ulnar fractures) occurred at 5° ± 2.6° of
rotation, isolated radial head fractures occurred at 44.4° ±
5.2° of rotation, and Essex-Lopresti fractures (radial head fractures with
tearing of the interosseous membrane) occurred at 70° ± 25.2°
of rotation. The distribution of Essex-Lopresti and radial head fractures was
significantly different at a cutpoint of 54° of forearm rotation (p =
0.009), and the distribution of radial head fractures and both-bone forearm
fractures was significantly different at a cutpoint of 10° of forearm
rotation (p = 0.001). The percent contact area of the radial head varied with
the injury pattern (p = 0.029). Marginal radial head fractures occurred at
46.7° ± 6.6° of rotation with a contact area of 30.9% ±
8.6%, while comminuted radial head fractures occurred at 74.4° ±
27.2° of rotation with a contact area of 53.9% ± 8.3%.
Conclusion: The amount of forearm rotation at the time of axial load
impact directly influenced the injury pattern. Furthermore, the radial head
contact area and the fracture severity increased in pronation compared with
supination.
Clinical Relevance: This model provides the basis for investigating
the mechanisms involved in forearm and elbow trauma under the application of
an axial impact load. Using this model, we established the relationship
between rotation and the fracture pattern incurred by the forearm and radial
head.

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