Posterior Elbow Coverage Using Whole and Split Flexor Carpi Ulnaris Flaps: A Cadaveric Study

Purpose The purpose of this study is to evaluate the coverage patterns of whole and split flexor carpi ulnaris (FCU) pedicle muscle flaps for posterior elbow soft-tissue defects. Methods Seventeen fresh-frozen cadaveric upper extremities were used. The whole FCU was raised to the dominant vascular pedicle and transposed proximally over the olecranon. The widths of coverage at 2-cm distances about the posterior elbow were measured. Widths were also measured after making 3 longitudinal cuts in the fascia and after suturing the muscle to adjacent soft tissue under tension. The FCU was also split into its ulnar and humeral heads along the central tendon. The larger ulnar head was transposed and the widths again measured. Mid-forearm circumference, elbow circumference, and ulnar length were assessed for ability to predict flap width. Results The whole muscle under no tension provided an average of 2.7 cm width coverage at the tip of the olecranon process. Cutting the fascia provided approximately 15% additional width and suturing the muscle to the surrounding soft tissue an additional 25%, to approximately 4 cm. The isolated FCU ulnar head provided approximately 75% of the width of the entire muscle. Mid-forearm circumference was the most predictive of flap width, and divisors were generated that improved the accuracy of predicting the width for outlier specimens. The dominant pedicle was a consistent distance relative to the end of the central tendon and the olecranon tip. Conclusions The whole and split FCU pedicle flaps provide predictable coverage for 2- to 4-cm posterior elbow soft-tissue defects. For especially large and small arms, the divisors improve accuracy in predicting flap width. Consistent locations of the olecranon tip and the end of the central tendon in relation to the dominant pedicle make them useful surgical landmarks.