Ulnar nerve dislocation at the elbow: review of the literature and report of three cases

Abstract

Ulnar nerve instability without compression at the cubital tunnel is not common and even more rare is a dislocating nerve. We review the literature regarding the etiology of instability, its incidence and treatment. Snapping around the medial humeral epicondyle can also be caused by a subluxing medial head of the triceps. This pathology may be accompanied by symptoms from the ulnar nerve. Differential diagnosis even intraoperatively is therefore essential if effective treatment is to be given. We also present our own experience on the subject consisting of three cases, one of them with bilateral instability. In only one case there were clinical findings suggesting nerve compression. All laboratory and screening tests were normal, except for the nerve conduction studies in this one case. The main symptom was strong pain, especially during manual activities. Only two of the four subluxing nerves required surgical treatment which in our case was by anterior submuscular or subcutaneous transposition of the ulnar nerve. As diagnosis is not always easy and is usually made on clinical grounds, we also present a clinical test that we believe to be diagnostic for the situation.

Keywords: Ulnar nerve dislocation; diagnosis; treatment.; triceps dislocation.

Fig. (1)

Case 1: The ulnar nerve (UN) immediately after skin incision and initial dissection. At the beginning of flexion the nerve overriding the medial humeral epicondyle (ME) and ready to dislocate anteriorly. FCU: Flexor carpi ulnaris, MHT medial head of triceps.

Fig. (2)

Further dissection.

Fig. (3)

Anterior submuscular transposition of the ulnar nerve completed.