Diagnostic Arthroscopy: Indications, Portals, and Techniques

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CHAPTER 37 Diagnostic Arthroscopy: Indications, Portals, and Techniques

Glen A. McClung, II, Larry D. Field, Felix H. Savoie, III

HISTORY

In 1932, Michael Burman concluded in the Journal of Bone and Joint Surgery that the elbow joint was “unsuitable for examination” arthroscopically.⁸ Since that time, advances in arthroscopy and equipment have made elbow arthroscopy safe and effective in the management of a variety of elbow disorders. Elbow arthroscopy is a technically demanding procedure that requires a thorough knowledge of the neurovascular anatomy of the elbow. The original indications for elbow arthroscopy only included the diagnosis and removal of loose bodies. As techniques have advanced, the indications for elbow arthroscopy have expanded to include the treatment of synovitis, osteochondritis dissecans, capsular contractures, arthritis, fractures, lateral epicondylitis, and instability.^28,^29,^34,⁴⁸

Elbow arthroscopy was originally performed with the patient in the supine position and the hand suspended to traction. Because of poor access to the posterior aspect of the elbow, Poehling et al.³⁵ popularized the prone position for elbow arthroscopy. The lateral decubitus position has been advocated by O’Driscoll and Morrey.²⁹ The arm is positioned with the involved side up, the elbow flexed at 90 degrees, and the arm supported by a padded bolster. This position allows better access to both anterior and posterior compartments.

INDICATIONS AND CONTRAINDICATIONS

The indications for elbow arthroscopy include the removal of loose bodies,^7,^18,^23,²⁶^–²⁸ ^,40 removal of osteophytes secondary to osteoarthritis,^25,³⁰ radial head resection,²⁰ release of capsular contractures and adhesions,^9,¹⁴ and the resection of symptomatic plica.^4,¹¹ Other in-dications include the treatment of osteochondritis dissecans,^6,^28,^37,⁴² fractures,^3,^24,²⁸ lateral epicondylitis,^5,⁴⁴ instability,⁴⁵ septic arthritis,⁴⁸ synovectomy,^3,⁴⁸ and evaluation of patients with chronic elbow pain.²⁸

Multiple studies have demonstrated the effectiveness of elbow arthroscopy for the diagnosis and treatment of loose bodies. Success rates have been reported in the 90% range.^7,^18,^26,²⁷ Elbow arthroscopy for loose bodies is indicated in symptomatic patients who fail to respond to conservative treatment. The operating surgeon should attempt to determine the etiology of the loose body. Loose bodies are often a result of osteochondritis dissecans. Other causes include trauma, arthritis, or synovial osteochondromatosis. It is essential that the operating surgeon determines the source of loose bodies because the outcome of the patient will be determined by the disease, not just the removal of loose fragments.⁴²

SURGICAL TECHNIQUES

ANESTHESIA

Elbow arthroscopy can be performed under general or regional anesthesia. General anesthesia allows for complete muscle relaxation and flexibility of the patient.³⁵ In an awake patient with regional anesthesia, the prone or lateral decubitus position may be poorly tolerated.¹⁷ Neurologic function can also be monitored postoperatively with general anesthesia alone.

Regional anesthesia with a scalene, axillary, or Beir intravenous regional block may also be used if the patient cannot undergo general anesthesia. The axillary block does not always achieve complete anesthesia about the elbow. Regional anesthesia may limit operative time secondary to longevity of the anesthetic agent or the intolerance of the patient to the tourniquet in a Beir block.

POSITIONING

Supine Position

In the supine position, first reported by Andrews and Carson ³ in 1985, the patient lies supine with the shoulder over the edge of the operating table. The shoulder is abducted to 90 degrees and is in neutral rotation with 90 degrees of elbow flexion. The elbow is suspended by a traction device that is attached to either the hand or forearm (Fig. 37-1).

FIGURE 37-1 Arthroscopy may be performed in the supine position, as noted with the elbow suspended to overhead traction as noted in this right elbow.

There are several advantages of the supine position in elbow arthroscopy.^19,²¹ The supine position allows the anesthesiologist an easier access to the patient’s airway, and there is more flexibility to the choice of anesthesia. The conceptualization of the intra-articular anatomy is facilitated with the elbow in the supine position with the elbow joint in a more familiar anatomic orientation. Conversion of an arthroscopic procedure to an open procedure is readily facilitated in the supine position when required.

Disadvantages of the supine position include the requirement for a traction device with the assistance of a second person to stabilize the arm during arthroscopy. Manipulation of the elbow is more difficult with the overhead traction device. Finally, this position provides poor access to the posterior compartment of the elbow joint.

Prone Position

In response to the disadvantages of the supine position, Poehling and associates ³⁵ described the prone position for elbow arthroscopy. The patient is placed prone on the operating table over chest rolls to ensure adequate ventilation. The shoulder is abducted to 90 degrees, and the arm is supported by an arm positioner or an arm board (Fig. 37-2). The arm board is placed parallel to the operating table, centered at the shoulder. A sandbag, foam support, or rolled blankets are placed under the upper arm to elevate the shoulder and allow the elbow to rest in 90 degrees of flexion.

FIGURE 37-2 Elbow arthroscopy may be performed in the prone position with a bolster under the upper arm, as noted in this figure.

Advantages of the prone position are improved access and visualization of the posterior compartment of the elbow. Because the forearm hangs freely from the arm board, the elbow is easily manipulated from near full flexion to full extension. In the prone position, the anterior aspect of the elbow is facing inferiorly toward the floor, which allows neurovascular structures to fall anteriorly away from the joint. This provides an additional margin of safety when establishing portals. No special equipment or additional personnel are needed because the elbow position on the arm board is stable. The prone position, like the supine position, allows for easy conversion to an open procedure.³⁹

Disadvantages of the prone position are associated with airway and patient positioning. Chest rolls, protective padded face masks, and pillows are needed to pad all prominences susceptible to pressure sores during the procedure. Regional anesthesia is usually not well tolerated by the patient. If general anesthesia becomes necessary secondary to failure of the block or patient anxiety, repositioning of the patient is required. Open approaches to the medial and lateral side are readily accessible however an anterior approach would require repositioning.

Lateral Decubitus Position

The lateral decubitus position, first described by O’Driscoll and Morrey,²⁹ combines the advantages of the supine and prone position while avoiding some of the pitfalls of each position. The patient is placed in the lateral decubitus position, with the arm positioned in an arm holder or over a bolster. The shoulder is flexed to 90 degrees and internally rotated, and the elbow flexed 90 degrees over a padded bolster (Fig. 37-3).

FIGURE 37-3 Prone positioning of the elbow may also be accomplished by placing the patient in the lateral decubitus position and using the elbow support device.

The surgical procedure is performed with the elbow in the prone position and thus provides the same advantages of the prone position. The lateral decubitus does allow for easier patient positioning, and patients can tolerate lateral decubitus position better if regional anesthesia is needed. This position allows a better access to the airway and is easier to convert from regional to general anesthesia if required. Disadvantages include the use of a padded bolster and the possibility of needing to reposition if an open procedure is required.

PORTALS

A thorough knowledge of the neurovascular anatomy of the elbow and its three-dimensional relationship to the surface anatomy is required to perform elbow arthroscopy. There are eight access portals that are used in elbow arthroscopy. These portals are determined by neurovascular and musculotendinous anatomy about the elbow. Arthroscopic treatment of the elbow may require the use of several of these portals because the elbow is a highly constrained joint. Because the complexity of arthroscopic procedures of the elbow has increased, the number of portals used has also increased with an emphasis on the proximal anterior portals.

Surface landmarks are marked on the skin before creating portals. Important landmarks to outline are the radial head, olecranon, lateral epicondyle, medial epicondyle, and ulnar nerve. Before making portals, the joint must be distended with 20 to 30 mL of sterile saline (see Fig. 37-1). This can be done by placing an 18-gauge spinal needle either in the olecranon fossa or the soft spot bounded by the lateral epicondyle, olecranon, and radial head. Neurovascular structures are displaced away from the joint with distension of the joint, which gives an additional margin of safety.^15,¹⁶

Proximal Anteromedial

Poehling and associates ³⁵ first described the proximal anteromedial portal in 1989. This portal is located 2 cm proximal to the medial epicondyle and just anterior to the medial intermuscular septum (Fig. 37-4). The medial intermuscular septum is identified by palpation, and the portal is made anterior to the septum so that the ulnar nerve is not injured. The blunt trocar is introduced into the portal, anterior to the septum, and aimed toward the radial head while maintaining contact with the anterior surface of the humerus. This allows the brachialis muscle to remain anterior and protect the median nerve and brachial artery. The trocar enters the elbow through the tendinous origin of the flexor-pronator group and medial capsule.¹⁷

FIGURE 37-4 The multiple portals are delineated on the elbow. Surface landmarks, including the ulnar nerve marked by the long, parallel lines, the medial and lateral epicondyles marked by the circles, and the various portals marked by the x’s, are shown in this patient’s left elbow in the prone position.

The proximal anteromedial portal has been recommended as the initial portal used with the patient in the prone or lateral decubitus position.^15,³⁵ This portal is thought to offer safer access and better visualization of the joint. In addition, fluid extravasation may be less with this portal compared with the anterolateral portal.¹⁵ Visualization of the entire aspect of the anterior aspect of the joint including the anterior capsule, trochlea, capitellum, coronoid process, radial head, and medial and lateral gutters can be obtained with this portal.

The primary structure at risk with this portal is the posterior branch of the medial antebrachial cutanenous nerve.⁴⁶ This nerve is located approximately 2.3 mm from the trocar. With the elbow in flexion, the median nerve is relatively safe, protected by the brachialis muscle, being located on average a distance of 12.4 to 22 mm from the trocar.^15,⁴⁶ The path of the trocar aims distally and is in a parallel orientation to the median nerve making injury to the nerve less likely. The ulnar nerve is located on average a distance of 12 to 23.7 mm from the portal.^15,⁴⁶ The ulnar nerve is not at risk as long as the portal is made anterior to the intermuscular septum. Contraindications to the use of this portal are a history of subluxation or transposition of the ulnar nerve from its groove.^15,^32,⁴⁶ Care must be taken to ensure that the ulnar nerve is not subluxed before anteromedial portal placement. This portal may be used in these circumstances only if the nerve is identified prior to trocar entry.

Anteromedial Portal

The anteromedial portal, first described by Andrews and Carson,³ is positioned 2 cm distal and 2 cm anterior to the medial epicondyle (Fig. 37-5). With the elbow flexed to 90 degrees, the blunt trocar is aimed at the center of the joint, passing through the flexor-pronator origin and the brachialis muscle before entering the joint capsule anterior to the medial collateral ligament. This portal may also be established by using an inside-out technique, with the arthroscope in the lateral portal.¹⁵ The entire anterior compartment of the elbow, especially the lateral structures, can be visualized from this portal. The medial antebrachial cutaneous nerve is at greatest risk of being injured, located on average 1 mm from the portal.^22,⁴⁶ The median nerve is in closer proximity to this portal being located on average a distance of 7 to 14 mm.^16,⁴⁶ Lindenfeld¹⁵ reports an average distance of 22 mm from the portal to the median nerve if this portal is established 1 cm anterior to the medial epicondyle.

FIGURE 37-5 In this view from the proximal anterior medial portal, multiple loose bodies are noted anterior to the radiocapitellar joint.

Proximal Anterolateral

The proximal anterolateral portal, described by Stothers and associates,⁴⁶ Field and associates,¹² and Savoie and Field⁴¹ is positioned 2 cm proximal and 1 to 2 cm anterior to the lateral epicondyle (Fig. 37-6). This portal may be used as the initial portal in elbow arthroscopy. The blunt trocar is aimed towards the center of the joint while maintaining contact with the anterior humerus, and pierces the brachioradialis muscle, brachialis muscle and lateral joint capsule before entering the anterior compartment. This portal allows visualization of the anterior compartment, specifically the lateral and anterior aspects of the radial head and capitellum, lateral gutter, anterior ulnohumeral joint, and anterior elbow capsule.

FIGURE 37-6 The proximal anterior-medial portal located approximately 2 cm superior and 2 cm anterior to the medial epicondyle is marked along with relevant neurovascular structures.

The structures at risk on the lateral side are the posterior branch of the lateral antebrachial cutaneous nerve and the radial nerve. The trocar in the proximal anterolateral portal lies on average 6.1 mm from the posterior branch of the antebrachial cutaneous nerve.⁴⁶ This portal was developed because of the proximity of the radial nerve to the standard anterolateral portal. With the elbow in 90 degrees of flexion and distended with fluid, the radial nerve is located an average distance of 9.9 to 14.2 mm from the proximal anterolateral portal in contrast to 4.9 to 9.1 mm from the standard anterolateral portal.^12,⁴⁶

Anterolateral Portal

The standard anterolateral portal, first described by Andrews and Carson ³ in 1985, is located 3 cm distal and 1 cm anterior to the lateral epicondyle (see Fig. 37-6). The blunt trocar is aimed toward the center of the joint and passes through the extensor carpi radialis brevis muscle and lateral joint capsule before entering the joint. This portal can also be established with an inside-out technique using the arthroscope in the anteromedial or proximal anteromedial portal. The arthroscope is advanced to the capsule lateral to the radial head. The arthroscope is then removed from the cannula and replaced with a blunt rod that tents the overlying skin. The skin is incised over the rod and a cannula is positioned over the rod and placed into the joint. It is imperative when using this technique that the blunt rod enters the capsule lateral to the radial head rather than anterior to it in order to avoid injury to the radial nerve.^15,^32,⁴⁶

The anterolateral portal offers visualization of the anterior medial aspect of the joint including the coronoid process, trochlea, coronoid fossa, and medial aspect of the radial head. Visualization of the lateral joint is better with the proximal anterolateral portal.¹² This portal is also useful as a working portal with the arthroscope in the proximal anteromedial portal, especially for procedures on the radial head.

Lynch and associates ¹⁶ have shown the anterolateral portal to be located 2 mm from the posterior antebrachial cutaneous nerve. The radial nerve lies 4.9 to 9.1 mm from this portal with the elbow in 90 degrees of flexion and the joint distended with fluid.^12,⁴⁶ Because of its proximity and increased risk to the radial nerve, most authors recommend a more proximal entry for this portal.

Midlateral Portal

The midlateral portal is located in the center of the triangular area bordered by the olecranon, lateral epicondyle, and the radial head. This portal is also known as the direct lateral portal or soft spot. The blunt trocar passes through the aconeous muscle and the posterior capsule and into the joint. This is the same path that an 18-gauge needle takes for initial distension of the joint. The midlateral portal offers visualization of the radial-ulnar joint, as well as the inferior aspect of the radial head and capitellum.

Instrumentation of the lateral gutter and posterior radiocapetellar joint may be used with this portal. There is minimal risk to neurovascular structures with this portal. The posterior antebrachial cutaneous nerve, approximately 7 mm away,¹ is the only structure at risk. Because of leakage of fluid into the soft tissues, it is advisable to delay this portal until the end of the operation.^32,^34,⁴⁶

Straight Posterior Portal

The straight posterior or transtriceps portal is located 3 cm proximal to the tip of the olecranon in the midline posteriorly ^33,³⁴ (Fig. 37-7). This portal allows visualization of the entire posterior compartment, as well as the medial and lateral gutters.¹⁷ The blunt trocar is advanced toward the olecranon fossa through the triceps tendon and posterior joint capsule. With the arthroscope in the posterolateral portal, the straight posterior portal can be used for distal humeral fenestration with a drill or burr in ulnohumeral arthroplasty to access the anterior compartment of the elbow.³² This portal may also be used for instrumentation in removal of loose bodies and excision of olecranon spurs.¹⁷

FIGURE 37-7 The standard anteromedial portal is delineated being approximately 2 cm distal and 2 cm anterior to the medial epicondyle. Pertinent neurovascular structures are delineated in this illustration well.

Posterolateral Portal

The posterolateral portal is located 3 cm proximal to the olecranon tip and just lateral to the triceps tendon (see Fig. 37-7). The blunt trocar is advanced toward the olecranon fossa, passing lateral to the triceps tendon to enter the joint through the posterolateral capsule. This is performed with the elbow held in 45 degrees of flexion in order to relax the triceps and posterior capsule.⁴⁶ Triceps tendon injury can be avoided by remaining close to the posterior humeral cortex with the blunt trocar. This portal is approximately 20 mm from the medial antebrachial cutaneous nerve and 25 mm from the posterior antebrachial cutaneous nerve.¹⁶ The posterolateral portal allows excellent visualization of the posterior compartment of the elbow as well as medial and lateral gutters. In examining the medial gutter from this portal, the operating surgeon must be aware of the location of the ulnar nerve, which lies just superficial to the medial capsule.^32,³⁵

Posterolateral II Portal

Access to the posterolateral aspect of the elbow can be obtained anywhere between the soft spot portal to the standard posterolateral portal, 3 cm proximal to the olecranon tip. This portal is usually placed just lateral to the olecranon process and can be moved proximally or distally as needed. Visualization through this portal usually consists of distally the posterior radiocapitellar joint and proximally across the olecranon into the olecranon fossa. It may be used for excision of lateral olecranon spurs, resection of posterolateral plica, and débridement of the radial aspect of the ulnohumeral joint. The triceps tendon and ulnohumeral cartilage are at risk with placement of this portal.⁴¹

PROCEDURE

Before taking a patient to the operating room for the removal of loose bodies, a careful history and physical examination must be performed. A history of prior surgeries, particularly those involving release or transposition of the ulnar nerve, should be obtained. Physical examination should include range of motion, stability, and a neurovascular examination. The ulnar nerve should be evaluated during elbow flexion to ascertain subluxation or dislocation of the nerve. Loose bodies are commonly located in the coronoid fossa, the olecranon fossa, and the posterior lateral gutter, and access to these sites must be obtainable by the surgeon. A complete and thorough evaluation of the joint is necessary because loose bodies can migrate to any area of the elbow.

General anesthesia is administered, and the patient is placed in the prone position on the operating table over chest bolsters to ensure adequate ventilation. All bony prominences are well padded, and the shoulder is abducted to 90 degrees. An arm board is placed parallel to the operating table and a sandbag is positioned under the arm to elevate the shoulder. The forearm is allowed to fall over the arm board with the elbow flexed to 90 degrees. A Mayo stand with the appropriate instruments are placed next to the surgeon and scrub nurse, while the video monitor and equipment are placed on the opposite side of the patient. A tourniquet is placed on the upper part of the arm and an esmarch is used to exsanguinate the extremity. Once the arm is prepped and draped, surface landmarks of the elbow are outlined including the medial and lateral epicondyle and the olecranon process (Fig. 37-8). Also the ulnar nerve is specifically palpated to confirm that it remains in the cubital tunnel and is not subluxated. An 18-gauge spinal needle is next placed into the straight posterior or soft spot portal, and 20 to 30 mL of sterile saline is injected into the joint. This usually results in slight extension of the elbow as the joint space is filled.

FIGURE 37-8 Three primary lateral portals being the proximal anterolateral portal, the anterosuperior lateral portal, and the distal anterolateral portal are delineated in this figure, along with their proximity to the radial nerve.

The proximal anteromedial is the initial portal established unless history of ulnar nerve transposition or subluxation prohibits its use. This portal is located 2 cm proximal to the medial epicondyle and anterior to the intermuscular septum. A No. 11 knife blade is used to incise skin only while a hemostat dissects to the joint capsule. With the elbow in 90 degrees of flexion, a small blunt trocar and cannula for the 4.5-mm arthroscope is aimed toward the radial head while maintaining contact with the anterior aspect of the humerus. Once inside the joint, an egress of fluid confirms intra-articular placement. A 4.5-mm, 30-degree arthroscope is introduced into the cannula with the inflow connected to the bridge on the scope.

With the arthroscope in the proximal anteromedial portal the entire anterior compartment of the elbow can be evaluated. From lateral to medial this includes examination of the lateral gutter, capitellum, radial head, anterior capsule, trochlea, coronoid process, and if properly placed, medial gutter. The arthroscopic evaluation initially includes inspection of the radiocapitellar joint through a range of motion in pronation and supination. This is performed to ensure that the radial head is congruent with the capitellum and that no subluxation exists and to evaluate the articular cartilage of the radial head. The arthroscope is then advanced anterior to the radiocapitellar joint, and the lens is rotated to visualize the capsule and undersurface of the extensor muscles. The ulnohumeral articulation is next evaluated by retracting and rotating the arthroscope so that the coronoid process is in view. By rotating the lens superiorly, the attachment of the capsule to the humerus is visible.

FIGURE 37-9 The two standard posterior portals most commonly utilized in the elbow are delineated in this figure.

Loose bodies are commonly found in the anterior compartment in the coronoid fossa (Fig. 37-10). Once the loose body is identified, a lateral portal is established using a spinal needle. For removing loose bodies the proximal anterolateral portal is preferred. The spinal needle is placed 2 cm proximal and 1 to 2 cm anterior to the lateral epicondyle, aiming toward the center of the joint. Once intra-articular placement is confirmed arthroscopically, the spinal needle is removed and a No. 11 blade knife is used to incise skin only in order to avoid damage to cutaneous nerves. A blunt trocar and cannula is then advanced into the joint while maintaining contact with the anterior humerus to avoid injury to the radial nerve. A grasper with teeth is introduced into the proximal anterolateral portal and used to remove the loose bodies. It may be necessary to “pin or stab” the loose body with an 18-gauge spinal needle, inserted through the mid anterolateral or anteromedial portal site, in order to provide resistance for grasping. The loose body should be rotated as it is being brought through the soft tissue so that it does not get lost. For larger loose bodies the portal may have to be enlarged in order to accommodate the size of the fragment. Otherwise, the loose body may need to be removed piece by piece.

FIGURE 37-10 These loose bodies may be removed from an anterolateral portal using a grasping device.

Once the loose bodies in the anterior compartment are removed, the posterior compartment is addressed. The cannula in the proximal anteromedial portal is left in place, and the inflow is attached so that the loose bodies are pushed to the posterior compartment. In the posterior compartment, loose bodies are usually located in the olecranon fossa (Fig. 37-11). The straight posterior portal is established using a No. 11 blade knife 3 cm proximal from the olecranon process and in the midline posteriorly. The blunt trocar and cannula are directed toward the olecranon fossa. Once loose bodies are identified, the posterolateral portal is established by placing a spinal needle 3 cm proximal to olecranon process and lateral to the triceps. Once the spinal needle is determined to be in the appropriate position arthroscopically, a No. 11 blade knife is used to incise only skin and a blunt trocar and cannula are introduced into the posterior compartment. Usually a motorized shaver is necessary to débride soft tissue in order to obtain full access to the olecranon fossa. The loose bodies can be removed from either the straight posterior or posterolateral portal. The tip of the olecranon should be carefully evaluated because this is often a source for loose bodies. The arthroscope is next directed toward the medial gutter. Using the opposite hand, the surgeon applies pressure in an alternating fashion to the soft tissues posterior to the medial epicondyle in a distal to proximal direction. This maneuver should “milk” any loose bodies from the medial gutter. “Hidden” loose bodies are often found in the posterolateral gutter.