Evaluation of the Role of Dynamic Elbow Stabilizers on Radiocapitellar Joint Alignment
Austin J Roebke, MD1, Richard Samade, MD, PhD1, Kanu S Goyal, MD2, Sonu Jain, MD, FACS3, Jesse Richards, MD1 and Amy Speeckaert, MD1, (1)The Ohio State University Wexner Medical Center, Columbus, OH, (2)The Ohio State University, Columbus, OH, (3)Departments of Plastic Surgery and Orthopaedic Surgery, The Ohio State University, Columbus, OH
Introduction: Radiographs are frequently utilized to determine appropriate radial head-capitellum alignment of elbow fracture-dislocation injuries. Use of regional anesthesia during surgical repair of elbow fracture-dislocations leads to temporary paralysis of elbow dynamic stabilizers, which may affect the radiocapitellar (RC) joint. The study aim was to determine the effect of the dynamic stabilizers on RC joint alignment, before and after administration of regional anesthesia.
Methods: A single institution study of 14 prospectively-enrolled patients with a self-control design was performed, with 1 anteroposterior (AP) and 9 lateral fluoroscopic images of the elbow (in the operative extremity) obtained from each patient. The lateral images were obtained with maximal forearm pronation, neutral rotation, and supination with the elbow (1) fully extended, (2) flexed to 90 degrees with 0 degrees of shoulder internal rotation (IR), and (3) flexed to 90 degrees with 90 degrees of shoulder IR. After obtaining 10 initial images, a supraclavicular regional block was performed to achieve less than 3/5 motor strength of the imaged elbow. Then, the same 10 images were again obtained in each patient. The paired t-test was used to compare carrying angles and RCRs between groups (significance level 0.05).
Results: The 14 patients had a mean age of 47.8±15.7 years and 10 (71.4%) were female. Significant differences between RCRs calculated before and after regional anesthesia were seen with (1) forearm neutral rotation / elbow flexed to 90 degrees / shoulder at 0 degrees of IR (2.25%±4.63% to -1.05%±6.12%, P = 0.0073), (2) forearm maximally supinated / elbow flexed to 90 degrees / shoulder at 0 degrees of IR (0.95%±8.96% to -3.02%±5.68%, P = 0.0396), and (3) forearm maximally supinated / elbow flexed to 90 degrees / shoulder at 90 degrees of IR (-3.27%±5.50% to -6.17%±5.33%, P = 0.0304). No significant difference was seen in carrying angles (15.5±4.09 to 16.6±4.25, P = 0.314).
Discussion/Conclusion: A statistically significant posterior subluxation of the RC joint (negative RCR) was found after paralysis of the dynamic stabilizers in three different combinations of shoulder, elbow and forearm positions. RC alignment was maintained, however, if the forearm was in maximal pronation. This confirms that the dynamic stabilizers play a role in elbow stability and that loss of their function alone can lead to posterior displacement of the radial head radiographically. These findings suggest that the best way to examine elbow stability intra-operatively is to do so with the forearm in maximum pronation.
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