Subcutaneous Ulnar Nerve Transposition Using Osborne’s Ligament as a Ligamentodermal or Ligamentofascial Sling

Ulnar nerve compression at the elbow is a common nerve compression syndrome in the upper extremity. There are multiple sites of compression of the ulnar nerve distal to the axilla. The most common site of ulnar nerve compression is at the cubital tunnel.¹ When ulnar nerve compression is clinically suspected, electromyography (EMG) and nerve conduction velocity studies (NCS) may be performed to help support the diagnosis. However, a false negative rate in excess of 10% is found in patients with clinical signs and symptoms of cubital tunnel syndrome.² Treatment of cubital tunnel syndrome involves nonsurgical treatments, including activity modification, use of nonsteroidal anti-inflammatory drugs, splinting, and physical therapy or surgical treatment.^3-5

Surgical management of cubital tunnel syndrome is indicated after a failed nonsurgical management or a presentation with motor weakness. The most common surgical treatments include in situ decompression, subcutaneous transposition, intramuscular transposition, submuscular transposition, and medial epicondylectomy, or their combination.⁶ However, optimal surgical management of cubital tunnel syndrome remains controversial.^2,7 The overall goal of surgery is to eliminate all sites of compression and obtain a tension-free nerve that glides smoothly.

After the initial concept of subcutaneous anterior ulnar nerve transposition was developed by Curtis⁸ in 1898, many different techniques have been derived including epineurial suture, fasciodermal sling, and subcutaneous to fascia suture.^8-10 Common complications of subcutaneous ulnar nerve transposition include nerve fibrosis, recurrent subluxation, and inadequate division of the intermuscular septum.⁹ Additionally, thin patients often have repeated trauma to their ulnar nerves after subcutaneous transposition.³  

The anatomy of the cubital tunnel is well described, but it has multiple names and descriptions throughout the literature. Osborne¹¹ originally described a transverse fibrous band as the fascial connection between the 2 heads of the flexor carpi ulnaris that forms the roof of the cubital tunnel. O’Driscoll and colleagues⁵ conducted a cadaver study and proposed calling Osborne’s band as the cubital tunnel retinaculum. They described 4 different variations of anatomy and the retinaculum as a 4-mm wide band of tissue located proximally in the cubital tunnel that is distinct from the arcuate ligament and the fascia between the 2 heads of the flexor carpi ulnaris.⁵ Green and Rayan¹² studied cubital tunnel anatomy and referred to the ligament that spans the medial epicondyle and the olecranon as the arcuate ligament, which is also distinct from the flexor carpi ulnaris aponeurosis. These variations in named anatomy make describing procedures around the cubital tunnel challenging. In this study, the fascial band between the 2 heads of the flexor carpi ulnaris, as originally described by Osborne,¹¹ will be referred to as Osborne’s ligament.

We describe a novel technique of anterior subcutaneous ulnar nerve transposition, where Osborne’s ligament is used as a sling to prevent ulnar nerve subluxation over the medial epicondyle. We also describe the results of our initial subset of patients who were treated with this technique.

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