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The medial epicondyle may act as a fulcrum causing deformation of the ulnar nerve during elbow flexion. Furthermore, ulnar neuropathy can be potentiated by dynamic instability of the ulnar nerve around and over the medial epicondyle. Anterior transposition techniques were designed to eliminate traction on the nerve from the medial epicondyle or mechanical irritation in the presence of dynamic instability. Subcutaneous anterior transposition has been advocated as a less morbid alternative to deeper transposition techniques (i.e. intramuscular or submuscular) as it requires less dissection. Multiple techniques have been reported to maintain the nerve in its subcutaneous position after transposition, utilizing a fasciodermal sling from the flexor-pronator mass, an adipose flap, the medial intermuscular septum, or even Osborne’s ligament. Care must be taken with anterior transposition to avoid creation of new sites of compression, particularly at the medial intermuscular septum and the flexor carpi ulnaris fascia. Subcutaneous ulnar nerve transposition has been found to be comparable to in situ decompression as well as submuscular and intramuscular transposition techniques in several randomized trials and large outcomes series.

Anterior transposition for cubital tunnel syndrome consists of the surgical decompression of the ulnar nerve followed by movement of the nerve anterior to its native retrocondylar location relative to the medial epicondyle. Three different types of anterior transposition have been described, including subcutaneous, intramuscular, and submuscular transpositions. These procedures were developed to not only decompress the ulnar nerve but also to reduce nerve traction during elbow flexion that is not addressed by in situ ulnar nerve decompression alone. However, transposition procedures may pose a greater risk of complications (Macadam SA, Gandhi R, Bezuhly M, Lefaivre KA, J Hand Surg Am 33:1314.e1–12, 2008; Zlowodzki M, Chan S, Bhandari M, Kalliainen L, Schubert W, J Bone Joint Surg Am 89:2591–2598, 2007; Staples R, London DA, Dardas AZ, Goldfarb CA, Calfee RP, J Hand Surg Am 43:207–213, 2018; Zhang D, Earp BE, Blazar P, J Hand Surg Am 42:294.e1–294.e5, 2017). Evidence for the superiority of in situ decompression vs transposition and the type of transposition is lacking. Rather, surgeons may choose to perform an ulnar nerve transposition based on specific clinical settings or simply surgical preference. The goals of this chapter are to define various indications for anterior transposition, to outline controversies regarding in situ ulnar nerve decompression vs anterior transposition, to describe operative techniques, and to report outcomes comparing transposition procedures and in situ decompression.

Critical review of surgical outcomes is vital to optimizing patient care. Multiple studies have ventured to address outcomes after cubital tunnel surgery. Due to variation in surgical technique, limited objective data, and inconsistency in measured outcome variables between studies, obtaining any generalized conclusions on anticipated postoperative outcomes remains somewhat challenging. This chapter reviews the available literature on outcomes after cubital tunnel release.

Cubital tunnel syndrome is a common neuropathy of the upper extremity. Patient symptoms typically consist of numbness in the ulnar side of the side and hand intrinsic muscle weakness. Physical examination and EMG/NCV are usually adequate to establish a diagnosis. Nonoperative management works approximately 50% of the time and consists of rest and splinting. Operative management can help the symptoms and prevent progression of disease. During surgical decompression, all sites of potential compression should be evaluated to give the patient the best chance for a successful outcome.