An incision is started 5 cm above the elbow joint, centered over the medial supracondylar ridge and the medial epicondyle, and passes to below the elbow joint.
The incision is usually crossed by the posterior branch of the medial cutaneous antebrachial nerve.
Be careful of this nerve branch during the dissection of the subcutaneous tissue; if it is divided, neuroma formation can be troublesome.
2. Identification of the ulnar nerve
Identify the ulnar nerve proximally between the triceps and the medial intermuscular septum, in the groove posterior to the medial epicondyle and distally between two heads of the flexor carpi ulnaris. Gently free and protect the ulnar nerve. If anterior transposition of the nerve becomes necessary, be careful to preserve the motor branch to the flexor carpi ulnaris.
It is essential that the OR report should clearly describe how the ulnar nerve has been protected, and the location of the nerve at the end of the operation.
3. Deep dissection
The ulnar nerve has been freed and is gently retracted with a vessel loop. Identify the medial supracondylar ridge of the humerus, the medial intermuscular septum, and the origin of the flexor/pronator muscle mass.
Release the medial intermuscular septum from the medial supracondylar ridge of the humerus for a distance of about 5 cm proximally. Retract anteriorly the flexor/pronator muscle mass to visualize the joint capsule. The planned capsulotomy is marked in red.
4. Opening the joint
Incise the capsule longitudinally and reflect anteriorly and posteriorly from the humerus as necessary.