Since their introduction in 1922, arthroscopic and endoscopic techniques have revolutionized orthopaedic treatment. Their utility in the shoulder and knee is well described, but widespread application of arthroscopic techniques in the elbow is a relatively recent phenomenon. The elbow joint itself presents some unique challenges because of its highly constrained nature, complex anatomy, and the proximity of important neurovascular structures. Despite these challenges, advances in instrumentation combined with increasing experience allow treatment of a wide range of disorders. Early indications for elbow arthroscopy in the athlete were limited to loose body removal and chondroplasty. These indications have expanded to arthroscopic treatment of lateral epicondylitis, osteochondritis dissecans, and posterolateral instability.
History
In considering the use of elbow arthroscopy, a thorough history is mandatory to elucidate the underlying diagnosis and location of the associated pathology. Of particular concern in the athlete are the presence of mechanical symptoms, altered range of motion, neurologic involvement, and precipitating activities. Previous treatment including medications, activity restriction, and physical therapy further refine the history. Elbow tendinopathy, osteochondritis dissecans, and instability are treated in detail in separate chapters of this textbook, and the reader is referred to these chapters for diagnostic pearls.
Physical Examination
A complete physical examination includes a careful assessment of range of motion, stability, neurovascular status, and the presence of an effusion. Specific diagnoses have commonly associated findings. Loss of terminal extension is often present in patients with osteochondritis dissecans, and valgus stress will often recreate pain at the lateral elbow. End-arc limitation of motion with pain is indicative of osteophyte impingement associated with osteoarthritis. Tenderness to palpation at the extensor origin and pain with resisted wrist extension are commonly seen in persons with lateral epicondylitis. The examination is further directed by the patient’s underlying diagnosis. Germane to elbow arthroscopy is ulnar nerve position, sensitivity, and subluxation, which must be known with certainty to avoid inadvertent injury during portal placement and to prevent aggravation of a mild, preexisting neuropathy.
Imaging
Standard anteroposterior, lateral, and oblique radiographs should be obtained for all patients. If osteochondritis dissecans is suspected, a 45-degree flexion view will better demonstrate capitellar lesions. Ultrasound has been used increasingly in the diagnosis of lateral epicondylitis but remains operator dependent. Computed tomography is used to assess bony anatomy and may demonstrate loose bodies, fragmentation, or collapse in advanced lesions; it is also helpful for preoperative planning of a debridement procedure for elbow arthritis. Magnetic resonance imaging (MRI) provides images of ligament, chondral, and synovial pathology and is standard in evaluation of osteochondritis dissecans, because the distinction between stable and unstable lesions often directs treatment.
Decision-Making Principles
Arthroscopy is, in essence, another means of exposure. Through multiple portals the surgeon is able to access the entire elbow, including the neck of the radius, the medial and lateral gutters, and the anterior and posterior compartments. Obtaining such exposure by open means entails considerable surgical trauma. Although arthroscopy can be minimally invasive with excellent visualization of articular surfaces, it must make the procedure easier, faster, less traumatic to the patient, safer, or more precise; otherwise, it should be aborted in favor of open approaches.
Treatment Options
Anesthesia
Elbow arthroscopy may be performed with administration of either a regional or nondipolarizing general anesthetic. The latter is advantageous for ease of positioning and immediate assessment of postoperative neurologic status, but use of paralytic agents should be avoided, if possible, to improve intraoperative safety. We prefer to use a regional anesthetic, which affords the benefit of improved postoperative pain control and is safer to administer than a nondipolarizing general anesthetic.
Positioning
The procedure may be performed with the patient in the supine or lateral decubitus position ( Fig. 64-1 ). The prone position, which was originally described by Poehling et al. in 1989, has been largely upended because of poor access to the anterior compartment and poor tolerance of a regional anesthetic. The lateral decubitus position is probably the most widely used position at present. Flexing the arm to 90 degrees over a padded bolster provides complete visualization of the joint and good stability of the extremity.
In our practice, we prefer use of the supine position with a shoulder positioning device. This position mimics a more natural orientation of the joint space, making it conceptually easier to appreciate the surrounding anatomy. The positioning device allows the arm to be moved intraoperatively for access to the anterior and posterior compartments and affords easy conversion to an open procedure if necessary.
Instrumentation
We typically use a 30-degree, 4.0-mm arthroscope. In certain circumstances, use of a 70-degree arthroscope is advantageous for improved visualization.
Fluid management is especially critical in elbow arthroscopy. The short distance between the joint capsule and skin causes rapid fluid extravasation with use of conventional, fenestrated cannulae. Use of special cannulae without side vents helps prevent this complication ( Fig. 64-2 ). Furthermore, increased visualization seen at higher inflow pressures (35 mm Hg) comes at the expense of significant swelling and markedly decreased working time (30 to 45 minutes). Maintaining lower pressures of 25 to 30 mm Hg and using strategically placed retractors permit an extended working time and improve visualization. Once portals are established, use of switching sticks minimizes the number of passes through the tissues and decreases the risk of neurovascular injury.
Portal Placement and Precautions
The proximity of critical neurovascular structures has been detailed in multiple anatomic studies ( Tables 64-1 and 64-2 ). Initial insufflation of the joint will displace vital structures from offending instruments, although the benefit may be minimal in patients with a stiff elbow. Risk is further minimized by establishing all portals while the elbow is flexed to 90 degrees. These portals should be made close to the capsular insertion on the supracondylar ridge because entrapped tissue between the portal and humerus decreases joint volume and compromises exposure.
| Neurovascular Structure | ANTERIOR PORTALS | |||
|---|---|---|---|---|
| Standard Anteromedial | Proximal Anteromedial | Standard Anterolateral | Proximal Anterolateral | |
| Medial antebrachial cutaneous nerve | 1 | 6 | — | — |
| Median nerve | 7 | 12 | — | — |
| Brachial artery | 8 | 18 | — | — |
| Ulnar nerve | — | 12 | — | — |
| Lateral antebrachial cutaneous nerve | — | — | — | 6 |
| Posterior antebrachial cutaneous nerve | — | — | 13 | — |
| Radial nerve | — | — | 1 | 10 |
| Neurovascular Structure | POSTERIOR PORTALS | ||
|---|---|---|---|
| Posterior Radiocapitellar | Transtriceps | Proximal Posterolateral | |
| Medial antebrachial cutaneous nerve | — | — | 25 |
| Ulnar nerve | — | 19 | 25 |
| Lateral antebrachial cutaneous nerve | 10 | — | — |
| Posterior antebrachial cutaneous nerve | 7 | 23 | 25 |
With the exception of the relatively safe posterior portals, standard technique includes making a small incision through skin only using a No. 15 blade followed by blunt dissection through the subcutaneous tissue and musculature down to the capsular level. In general, trocars with blunt tips are used, although in certain instances, greater sharpness will facilitate penetration of thickened, contracted capsules without anterior deviation.
Standard Anteromedial Portal
The standard anteromedial portal is located 2 cm distal and 2 cm anterior to the medial epicondyle ( Fig. 64-3 ). The arthroscope is aimed toward the center of the joint and will pass through the common flexor origin, deep to the median nerve and brachial artery. The arthroscope provides an excellent view of the anterior compartment of the joint, especially the radiocapitellar joint, mid to lateral coronoid, and trochlea. The proximal radioulnar joint articulation may be obstructed by the coronoid process, and the medial ulnohumeral articulation is difficult to see. Pronation and supination will allow a 260-degree arc of visibility of the radial head.
The structure at greatest risk is the medial antebrachial cutaneous nerve, which is located on average as little as 1 mm from the trocar, with considerable variability in its branching and location. Blunt subcutaneous tissue dissection is especially important in this location. The median nerve is located an average of 7 to 14 mm away. On the basis of these previous anatomic studies, Verhaar et al. instead advocate placement of the portal only 1 cm anterior to the medial epicondyle, thereby increasing the safe distance to 18 mm on average. The nerve is still at increased risk relative to the proximal anteromedial portal based on its course relative to the portal orientation. The brachial artery also rests in close proximity just lateral to the nerve, with its location an average of between 8 to 17 mm away.
Proximal Anteromedial Portal
The proximal anteromedial portal provides an excellent view of the entire anterior compartment and is often advocated as the best starting point for elbow arthroscopy. As described by Poehling et al., this portal is created 2 cm proximal to the medial epicondyle and just anterior to the intermuscular septum to avoid injury to the ulnar nerve (see Fig. 64-3 ). An additional margin of safety is provided by placing this portal a full 1 cm anterior to the septum, which in our experience has the added advantage of a better mechanical arc of motion of the scope before levering against the supracondylar ridge of the humerus. The blunt trocar should slide along the anterior surface of the humerus while aimed toward the coronoid fossa. The brachialis muscle provides an additional layer of protection from penetration of the median nerve. Aiming this trocar more parallel (rather than perpendicular) to the median nerve increases the safety of introduction.
When establishing this portal, the medial antebrachial cutaneous nerve remains at most risk of injury. Anatomic studies have shown that on average it is 6 mm from the cannula, but variations in branching may reduce this distance to as close as 2 mm. If the aforementioned technique is used, the median nerve is relatively safe, at an average distance of 12 to 22 mm away. Further away and at less risk is the brachial artery, at an average distance of 18 mm. The ulnar nerve is an average distance of 12 to 25 mm away and is also considered to be relatively safe from this portal as long as the trocar is kept anterior to the intermuscular septum. However, one case report shows that the protection afforded by the septum may be negated if the portal is moved farther proximal than the recommended 2 cm from the medial epicondyle. Furthermore, the surgeon must be aware of the presence of previous ulnar nerve transposition or anterior subluxation before placing the portal.
Historically, any anatomic distortion of this region was considered a contraindication to this portal because of potential ulnar nerve injury. More recent studies have maintained that by taking appropriate precautions and with a thorough examination it can be made safely despite anterior transposition. A systematic approach to placement of the proximal medial portal, taking into account the ability to localize the ulnar nerve by palpation, was well described in 2010 by Sahajpal et al. In some cases, a mini open procedure was recommended, particularly with prior submuscular transposition. In general, we consider a medial portal to be a relative contraindication after a subcutaneous ulnar nerve transposition and absolutely contraindicated after submuscular ulnar nerve transposition.
Standard Anterolateral Portal
The standard anterolateral portal was originally described by Andrews and Carson as 3 cm distal and 1 cm anterior to the lateral epicondyle (see Fig. 64-3 ). The value of this portal has been called into question because similar visualization at less risk has been described from the proximal anterolateral portal. The posterior antebrachial cutaneous nerve averages 13 mm from the portal. The radial nerve, averaging between 1 to 7 mm away from this portal, is at increased risk compared with a more proximal portal (10 to 14 mm).
Proximal Anterolateral Portal
The proximal anterolateral portal is located 2 cm proximal and 1 to 2 cm anterior to the lateral epicondyle (see Fig. 64-3 ). It allows for a more consistent view of the radiocapitellar joint than the standard anterolateral portal. The sheath should be directed toward the center of the joint with the trocar in contact with the anterior humerus. The capsule is pierced after traversing the brachioradialis and extensor carpi radialis longus muscles.
The posterior branch of the lateral antebrachial cutaneous nerve is located an average of 6 mm away. The radial nerve is located an average of 10 to 14 mm away with elbow flexion, which is a safer distance than with the standard anterolateral portal and has been advocated as a good starting point in elbow arthroscopy to minimize risk without sacrificing visualization.
Posterior Radiocapitellar (“Soft Spot”) Portal
The posterior radiocapitellar portal is located in the center of the anatomic triangle bounded by the lateral epicondyle, olecranon, and radial head (see Fig. 64-3 ). It is often used for initial distention of the joint but may be used for visualization as well, providing access to the posterior radiocapitellar and proximal radioulnar joints. This portal is an attractive option because of its relative safety; however, the minimal distance between the capsule and skin at this site makes it especially prone to extravasation of fluid into surrounding soft tissues. The only structures at risk from this approach are the lateral antebrachial cutaneous nerve and posterior antebrachial cutaneous nerve, which on average are 10 mm and 7 mm away from the trocar, respectively.
Straight Posterior (Transtriceps) Portal
The straight posterior portal is located 3 cm proximal to the olecranon tip in the midline of the humerus centered between the epicondyles (see Fig. 64-3 ). The trocar will pass through the triceps tendon centrally and into the olecranon fossa. It allows visualization of the entire posterior compartment, including both the medial and lateral gutters. Compared with the other portals it is relatively safe, passing on average within 19 to 25 mm of the ulnar nerve and 23 to 29 mm of the posterior antebrachial cutaneous nerve.
Proximal Posterolateral Portal
The proximal posterolateral portal is classically placed 4 cm proximal to the olecranon tip and just lateral to the palpable edge of the triceps tendon (see Fig. 64-3 ). The trocar is again advanced toward the olecranon fossa, passing just lateral to the tendon and through the posterolateral capsule. It too is quite safe, with only the ulnar nerve and medial and posterior antebrachial cutaneous nerves at risk. These nerves each average 25 mm from the trocar.
Accessory Portals
The distal posterolateral portal is used to view the posterior compartment, lateral gutter, posterior radiocapitellar joint, proximal radioulnar joint, and medial gutter while allowing the transtriceps portal to be used for a shaver or a resecting forceps.
Another useful accessory portal is the anterior radiocapitellar portal just anterior and proximal to the joint. It should only be made under direct visualization from the medial portal because it lies closest to the radial nerve. Extreme caution should be used when inserting the trocar here because anterior deflection along the capsule will place the radial nerve at risk.
A distal ulnar portal described by van den Ende et al. augments visualization of the posterior radiocapitellar joint and provides a good trajectory for instrument insertion. It is located 3 cm distal to the posterior radiocapitellar joint just lateral to the palpable ulna edge.
Order of Portal Placement
Our preference is to start in the posterior compartment unless contraindicated by the patient’s disease because this dissection is frequently more difficult than the anterior approach. For the anterior compartment, some surgeons advocate starting medially or laterally, but entering whichever side is easier promotes intraoperative flexibility. Initial placement of the medial portal, however, carries less risk from a neurovascular standpoint and allows the lateral portals to be made safely and precisely under direct visualization.
The patient is positioned supine on the operating table with the elbow supported over the patient’s chest in the shoulder positioner for access to the posterior compartment. Surface landmarks are marked, including the medial and lateral epicondyles, olecranon, proximal ulna, radial head, radiocapitellar joint, and path of the ulnar nerve. Proposed portals are marked out prior to any anatomic distortion from joint distention during the procedure ( Fig. 64-4 ). The elbow is passively flexed and extended to detect potential subluxation of the ulnar nerve. The limb is exsanguinated, and the tourniquet is inflated.
The transtriceps portal is established through a stab incision directly down to the bone of the distal humerus followed by insertion of a 30-degree arthroscope. Flow is set to 25 to 30 mm Hg to minimize fluid extravasation and is increased only transiently if necessary to identify and control bleeding. The proximal or distal posterolateral portal is established as a working portal in a similar fashion, and a shaver is introduced into the posterior compartment. Fat pad debridement is necessary to establish a viewing space ( Fig. 64-5 ), and then the preferred progression is dissection distally along the lateral column to identify the lateral gutter and the tip of the olecranon. Limited flexion and extension of the elbow will confirm the location of the joint. The arthroscope is then advanced medially along the tip of the olecranon until the medial gutter is seen. The medial column may then be dissected.
The posterior radiocapitellar joint can be visualized by passing the arthroscope along the lateral gutter over the distal humerus until the base of the coronoid and radial head come into view. A 3.5-mm shaver in the posterior radiocapitellar “soft spot” portal will help debride any localized synovitis. Loose bodies are removed with a grasper or cut into morsels with the shaver. Larger bodies may be pushed out of the joint with the cannula and then guided with the grasper.
The arm is repositioned for access to the anterior compartment. The proximal anteromedial portal is established as a viewing portal. The proximal anterolateral portal is then established under direct visualization and used for instrumentation. The anterior compartment inspection consists of the anterior radiocapitellar joint, proximal radioulnar joint, coronoid, and coronoid fossa ( Fig. 64-6 ). Switching viewing portals allows for complete inspection of the remainder of the joint.
