Posterior Approach to the Elbow with Olecranon Osteotomy
Posterior Approach to the Elbow with Olecranon Osteotomy
The posterior approach provides the best possible view of the bones that
comprise the elbow joint.1,2 Although it is basically a safe and reliable operative technique, it does have one major drawback: It requires an osteotomy of the olecranon on its articular surface, creating another “fracture” that must be internally fixed. The uses of the posterior approach include the following:
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Open reduction and internal fixation of fractures of the distal humerus3,4
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Removal of loose bodies within the elbow joint
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Treatment of nonunions of the distal humerus
Extension contractures of the elbow can be treated by using some portions of this approach to lengthen the triceps muscle, without performing an olecranon osteotomy.
Position of the Patient
Exsanguinate the limb by elevating it for 3 to 5 minutes and then apply a tourniquet as high up on the arm as possible. Place the intubated patient prone on the operating table, ensuring adequate padding for the chest and pelvis to allow free movement of the abdomen during respiration. Abduct the arm about 90 degrees and place a small sandbag underneath the tourniquet, elevating the upper arm from the operating table. Allow the elbow to flex and the forearm to hang over the side of the table (Fig. 3-1).
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Figure 3-1 Position of the patient on the operating table.
Landmarks and Incision
Landmark
Palpate the large, bony olecranon process at the upper end of the ulna. It is conical and has a relatively sharp apex.
Incision
Make a longitudinal incision on the posterior aspect of the elbow. Begin 5 cm above the olecranon in the midline of the posterior aspect of the arm. Just above the tip of the olecranon, curve the incision laterally so that it runs down the lateral side of the process. To complete the incision, curve it medially again so that it overlies the middle of the subcutaneous surface of the ulna. Running the incision around the tip of the olecranon moves the suture line away from devices that are used to fix the olecranon osteotomy and away from the weight-bearing tip of the elbow (Fig. 3-2).
Internervous Plane
There is no true internervous plane, because the approach involves little more than detaching the extensor mechanism of the elbow. The nerve supply of the triceps muscle (the radial nerve) enters the muscle well proximal to the dissection.
Superficial Surgical Dissection
Incise the deep fascia in the midline. Palpate the ulnar nerve as it lies in the bony groove on the back of the medial epicondyle and incise the fascia overlying the nerve to expose it. Fully dissect out the ulnar nerve and pass tapes around it so that it can be identified at all times (Fig. 3-3). Do not use these tapes for retraction as this can create a traction lesion to the nerve.
If a screw is going to be used to fix the olecranon osteotomy, drill and tap the olecranon before the osteotomy is performed.5
Score the bone longitudinally with an osteotome so that the pieces can be aligned correctly when the osteotomy is repaired (see Fig. 3-3, inset).
Make a V-shaped osteotomy of the olecranon about 2 cm from its tip using an oscillating saw. The apex of the V is directed distally. A V-shaped osteotomy gives greater stability than a transverse osteotomy after fixation. Divide the bone until it is cut through almost entirely. Snap the remaining cortex by wedging the two cut surfaces apart with an osteotome. This will cause an irregularity in the osteotomy, allowing it to key together better during reconstruction (see Fig. 3-3, inset).
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Figure 3-2 Incision for the posterior approach to the elbow.
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Figure 3-3 Dissect the ulnar nerve from its bed and hold it free with tape. Predrill the olecranon before performing an osteotomy for easy reattachment. A V-shaped osteotomy is inherently more stable than a transverse osteotomy.
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Figure 3-4 Perform a V-shaped osteotomy of the olecranon and retract it proximally, with the triceps muscle attached. Strip a portion of the joint capsule with an osteotome.
Deep Surgical Dissection
Strip the soft tissue attachments off the medial and lateral sides of the portion of the olecranon that has been subjected to osteotomy and retract it proximally, elevating the triceps from the back of the humerus (Fig. 3-4). The posterior aspect of the distal end of the humerus is directly underneath; subperiosteal dissection around the medial and lateral borders of the bone allows exposure of all surfaces of the distal fourth of the humerus (Fig. 3-5). Note that full exposure seldom will be needed. Preserve as many of the soft tissue attachments to bone as possible when the approach is used for open reduction and internal fixation of fractures. Stripping excessive soft tissue attachments off the bone leaves the bone
fragments without a vascular supply and jeopardizes healing.
Be careful not to extend the dissection proximally above the distal fourth of the humerus, because the radial nerve, which passes from the posterior to the anterior compartment of the arm through the lateral intermuscular septum, may be damaged. Flex the elbow to relax the anterior structures if they need to be elevated off the front of the humerus (see Fig. 2-41).
The ulnar nerve must be kept clear of the operative field during all stages of the dissection. Some surgeons advise routine anterior transposition of the nerve during closure, especially if implant removal is anticipated in the future.
Dang
Nerves
The ulnar nerve is in no danger as long as it is identified early and protected, and excessive traction is not placed on it. It is at most risk when transverse K wires are inserted from the lateral side that may overpenetrate the medial cortex.
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Figure 3-5 Dissect around the medial and lateral borders of the bone to expose all
the surfaces of the distal fourth of the humerus.
The median nerve lies anterior to the distal humerus. It may be endangered if the anterior structures are not stripped off the distal humerus in an epiperiosteal plane. In cases of fracture, this dissection has usually been done for you. In the treatment of nonunions or when the approach is used for osteotomies, a strictly subperiosteal plane must be used to avoid damage to the nerve (see Fig. 3-5, inset).
The radial nerve is at risk if the dissection ventures farther proximally than the distal third of the humerus, one handbreadth above the lateral epicondyle (see Fig. 2-43).
Vessels
The brachial artery lies with the median nerve in front of the elbow. It should be afforded the same protection as the nerve (see Fig. 3-5, inset).
Special Points
Great care must be taken to realign the olecranon correctly during closure. Alignment after fractures is easy, because the uneven ends of the bone usually fit snugly, like a jigsaw puzzle. Osteotomies may result in flat surfaces, however, and can make accurate reattachment difficult (see Fig. 3-3). Also the oscillating saw will remove approximately 1 mm of bone making true anatomical reduction of the fracture impossible.
How to Enlarge the Approach
Extensile Measures
Proximal Extension. The posterior approach cannot be extended more proximally than the distal third of the humerus because of the danger to the radial nerve (see Figs. 2-43 and 2-47).
Distal Extension. The incision can be continued along the subcutaneous border of the ulna, exposing the entire length of that bone