Medial approach to the pediatric distal humerus
1. Main indication for medial approach in trauma
The main indications for a medial approach to the distal humerus are:
- Open fixation of medial epicondylar fractures
- Visualization of the medial epicondyle for safe K-wire insertion when using bilateral crossed K-wiring
- Ulnar nerve exploration
Note: The medial approach, including opening of the joint, is not an ideal procedure for supracondylar fractures.
2. Skin incision
The incision is started 2-3 cm above the elbow joint, centered over the medial supracondylar ridge and the medial epicondyle, and passes to below the elbow joint.
For visualization of the prominence of the medial epicondyle for K-wire insertion, a 1.5 cm skin incision and blunt dissection of the subcutaneous tissue is sufficient.
Note: The incision is usually crossed by the posterior branch of the medial cutaneous antebrachial nerve. Care must be taken of this nerve branch during the dissection of the subcutaneous tissue; if it is divided, neuroma formation can be troublesome.
3. Identification of the ulnar nerve
The ulnar nerve is identified proximally between the triceps muscle and the medial intermuscular septum, in the groove posterior to the medial epicondyle and distally between two heads of the flexor carpi ulnaris.
The ulnar nerve is gently freed and protected. If anterior transposition of the nerve becomes necessary, care must be taken to preserve the motor branch to the flexor carpi ulnaris.
4. Deep dissection
The ulnar nerve is then gently retracted with a latex loop, or a broad small smooth retractor.
The medial supracondylar ridge of the humerus, the medial intermuscular septum, and the origin of the flexor/pronator muscle mass should be identified.
The medial intermuscular septum is released from the medial supracondylar ridge of the humerus for a distance of about 3 cm proximally.
5. Opening the joint
If there is an indication to open the joint, the following steps should be followed.
The flexor/pronator muscle mass is retracted anteriorly to expose the joint capsule. The planned capsulotomy is marked here in red.
The capsule is incised longitudinally and reflected anteriorly and posteriorly from the humerus as necessary.
6. Closure
The capsule is closed with continuous resorbable sutures (3/0).
Skin and subcutaneous tissue are closed with fine resorbable sutures (this avoids any distress to the child in removing nonabsorbable sutures).
