THOMPSON APPROACH TO THE PROXIMAL RADIUS

USES

This approach is used primarily for plating of radius fractures.

ADVANTAGES

The approach through the dorsolateral aspect of the forearm makes patient positioning easy. When used for plating both bone fractures of the forearm, the arm does not need to be repositioned for the ulnar plate.

DISADVANTAGES

The major disadvantage is that this approach puts the radial nerve at considerable risk.

STRUCTURES AT RISK

The major structure at risk is the posterior interosseous (deep branch of the radial nerve), which enters the supinator and then goes down the arm to innervate the other dorsal musculature. Because this approach comes down directly over the midportion of the muscle belly, great care must be taken to identify the nerve and gently retract it.

Vigorous retraction on the brachioradialis can also damage the sensory branch of the radial nerve.

TECHNIQUE

With the forearm pronated, an incision is made starting just anterior to the lateral epicondyle and proceeding distally toward the middle of the wrist. The incision is carried through the subcutaneous tissue. The interval between the extensor carpi radialis brevis and the extensor digitorum communis is identified and developed. Once you are deep to those muscles, the supinator is immediately apparent. The radial nerve, however, is not seen because it is within the substance of the muscle, and it must be carefully identified and freed. It is usually necessary to split the fibers of the supinator to protect the nerve. If possible, the proximal radius can be supinated so that the supinator muscle can be stripped off of the radius right at its insertion. With fractured forearms, however, this is usually difficult, and positioning the wrist does not change the position of the proximal fragment. Care must be taken when stripping the supinator. According to Hoppenfeld, 25% of the time the posterior interosseous nerve is actually on the undersurface of the supinator, not within its muscle belly, and is in direct contact with the proximal radius in the region of the radial neck. Aggressive stripping can then damage the nerve. Once the supinator is off of the radius, the pronator teres is seen coming in from the opposite side. If necessary, it too can be taken off subperiosteally.

TRICKS