SURGICAL APPROACHES TO THE UPPER ARM AND ELBOW
The most common surgical approaches to the upper arm and elbow include the anterolateral approach to the humerus, the lateral or Kocher approach to the elbow, and posterior approaches to the elbow. Arthroscopic elbow techniques are also becoming more frequently used.
The anterolateral approach to the humerus is most commonly used for plating fractures of the humeral shaft. The incision is made at the deltopectoral interval proximally and then runs along the lateral border of the biceps muscle distally. An internervous plane is utilized between the deltoid (axillary nerve) and pectoralis major (medial and lateral pectoral nerves) proximally. More distally, after retracting the biceps medially, the brachialis muscle is split longitudinally along the outer third of the muscle, utilizing an internervous plane between its medial (musculocutaneous nerve) and lateral fibers (radial nerve). Neurovascular structures at risk with this approach include the axillary nerve and anterior humeral circumflex vessels proximally; the radial nerve as it runs in the spiral groove on the posterior surface of the midshaft of the humerus and more distally as it emerges between the brachioradialis and brachialis muscles laterally; and the musculocutaneous nerve, in its location on the surface of the brachialis muscle and deep to the biceps muscle. More distal fractures of the humeral shaft may be difficult to expose with the anterolateral approach, owing to the proximity. In these situations, a posterior approach to the humerus may afford better exposure. The humeral shaft can be exposed posteriorly either by splitting the triceps muscle down the midline, by taking care to identify the radial nerve, or by elevating the triceps muscle along its lateral border and reflecting all three heads of the muscle medially. The radial nerve is identified in the latter technique as it passes through the lateral intermuscular septum from posterior to anterior.
The lateral or Kocher approach to the elbow is commonly used for many procedures on the lateral side of the elbow, such as fracture fixation (radial head, capitellum), radial head replacement, and lateral collateral ligament repair or reconstruction. The approach utilizes the internervous plane between the extensor carpi ulnaris (posterior interosseous nerve) anteriorly and the anconeus (radial nerve) posteriorly. Neurovascular structures at risk include the posterior interosseous nerve and radial nerve. The posterior interosseous nerve can be protected by keeping the forearm pro- nated, and the radial nerve is avoided by not straying too far proximally or anteriorly.
Posterior approaches to the elbow can involve mobilization of the triceps tendon or leave the triceps intact. The most common method of moving the triceps is by olecranon osteotomy. This technique reflects the olecranon and triceps insertion proximally to expose the distal humerus and elbow joint. Outstanding exposure of the joint is achieved, and the approach is particularly useful in fixation of complex, intra-articular distal humerus fractures and total elbow arthroplasty. Non-union of the olecranon osteotomy site is a risk with this technique, however. The Bryan-Morrey posterior approach is an alternative to olecranon osteotomy and involves reflection of the extensor mechanism laterally, including the triceps and anconeus. This approach can be used for similar indications as an olecranon osteotomy. Although joint exposure is not quite as good, there is no risk of osteotomy nonunion with this technique.
Elbow arthroscopy is more commonly being used as a surgical technique. Correct portal placement is essential to avoid neurovascular injuries. The proximal anterolateral and proximal anteromedial portals are most commonly utilized to visualize the anterior compartment of the elbow. The anteromedial portal is made approximately 2 cm proximal to the medial epicondyle and anterior to the intermuscular septum. The ulnar nerve and medial antebrachial cutaneous nerve are at risk with this portal. The anterolateral portal is similarly made on the lateral side of the elbow, taking care to stay anterior to the humerus. The radial nerve is most at risk with this portal. The posterocentral and posterolateral portals are most commonly employed to visualize the posterior compartment of the elbow. Both portals are made approximately 3 cm proximal to the tip of the olecranon. Finally, the direct lateral “soft spot” portal is made at the “soft spot” on the lateral side of the elbow to help with visualization and instrumentation in the lateral gutter, such as when working on a capitellar osteochondritis dissecans. The posterior a tebrachial cutaneous nerve is at risk with this portal.