Arthroscopy of the shoulder: Technique and

Transcription

1 Arthroscopy of the shoulder: Technique and normal anatomy JAMES R. ANDREWS,* MD, WILLIAM G. CARSON, Jr, MD, AND KENNETH ORTEGA, MD, CAPT, MC, USA From the Hughston Orthopaedic Clinic, P.C., Columbus, Georgia, and Tulane University School of Medicine, Division of Orthopaedics, Sports Medicine Section, New Orleans, Louisiana ABSTRACT We present our technique of diagnostic and surgical arthroscopy of the shoulder and describe the normal and normal variational arthroscopic anatomy of the structures within the shoulder joint. To ensure accuracy, strict attention is given to consistent patient position and technical detail. Posterior and anterior portals are consistently located with the aid of bony anatomic landmarks. Using a large diameter angled arthroscope, structures within the shoulder joint are identified and examined in sequential order. Diagnostic arthroscopy of the shoulder can be systematic and reproducible when the surgeon is knowledgeable of the normal and normal variational anatomy of the shoulder and when attention is given to accurate placement of the arthroscopic portals and to consistent surgical technique. Over the past 10 years, arthroscopy has become firmly established both as a diagnostic and therapeutic modality, especially regarding the knee joint. Its use in the evaluation of the shoulder joint has been less firmly established, however, although several reports of its use exist.,,, 14-17,28 Because the shoulder joint is a common source of pain, most physicians are familiar with the usual diagnostic modalities of evaluating the shoulder, such as routine radiographs and arthrography. Recent reports of advanced radiologic techniques, including arthrotomography, have furthered our ~,19, 22 knowledge of the shoulder joint. Arthroscopy of the shoulder has increased our knowledge of the anatomy and pathologic processes of this complex joint even further. To be effective, however, arthroscopic examination must be systematic and reproducible. In this report, we present our technique of shoulder arthroscopy and describe the normal arthroscopic anatomy of the shoulder. * Address correspondence and repnnt requests to James R Andrews, MD, Hughston Orthopaedic Clinic, P C 6262 Hamilton Road, Columbus, GA t Fellow m Sports Medicne, Hughston Orthopaedic Clinic, P C t Resident n Sports Medicne, Hughston Orthopaedic Clirnc, P C 1 SURGICAL TECHNIQUE After general endotracheal anesthesia is administered, the patient is positioned in the lateral decubitus position with the torso supported by a bean bag or kidney rest. The arm is placed in a skin traction apparatus or in a prefabricated wrist gauntlet. The traction device is connected to an overhead pulley, and the arm is placed at approximately 70 of abduction (Fig. la) and 15 of forward flexion (Fig. 1b). The traction rope is secured to a suspended weight via a ropeand-pulley system. The shoulder is prepared and draped using sterile towels and transport adhesive drapes. The surgeon stands posterior to the patient, the first assistant toward the patient s feet, and the second assistant opposite the surgeon over the anterior aspect of the patient or on the same side as the surgeon and positioned toward the patient s head. The bony anatomic landmarks are identified and outlined with a pen. These are the anterolateral and posterolateral borders of the acromion, the distal clavicle, the coracoid process, and the posterior aspect of the glenohumeral joint. The posterior portal, the preferred approach for diagnostic arthroscopy, is located approximately 3 cm inferior and slightly medial to the posterolateral tip of the acromion. This point corresponds to the &dquo;soft spot&dquo; on the posterior aspect of the shoulder that comprises the interval between the infraspinatus and teres minor muscles. Accurate placement of the arthroscope is facilitated by palpating the coracoid process anteriorly with the index finger and feeling for the posterior soft spot with the thumb. As the suspended arm is internally and externally rotated, the humeral head can be palpated beneath the thumb, and the exact location of the glenohumeral joint can be confirmed. An 18 or 20 gauge spinal needle is inserted through this posterior soft spot and directed anteriorly toward the coracoid process, which is palpated by the surgeon s index finger (Fig. 2). Forty to fifty centimeters of saline solution is then injected to distend the joint. The presence of free backflow will confirm correct placement of the needle. After the spinal needle is removed, a 5 mm skin incision is made at the point of the needle s insertion, and the cannula and the sharp trocar are inserted anteriorly toward the coracoid process (Fig. 3). When the capsule has been

2 2 When the procedure is complete, 30 cc of 0.5% bupivacaine (Marcaine) is injected into the shoulder joint through the sleeve of the arthroscope. The puncture wounds are covered with vaseline and gauze, and a sterile bulky dressing is applied to the shoulder. ARTHROSCOPIC ANATOMY Biceps tendon The biceps tendon is the first structure identified after the arthroscope is introduced into the shoulder (Fig. 6). With the patient positioned as described, the tendon is oriented approximately 10 to 15 away from an imaginary vertical line. It attaches to the supraglenoid tubercle at the posterosuperior aspect of the glenoid and, in this area, it is intimately related to and continuous with the glenoid labrum (Fig. 7). When the patient s arm is rotated externally to facilitate visualization, the biceps tendon can be followed anteriorly to the bicipital groove. Its surface should appear Figure 1. Lateral decubitus position with the arm connected to overhead traction. The arm is abducted to 70 (a) and forward flexed 15 (b). entered, the sharp trocar is replaced by a blunt trocar. The shoulder joint is then entered and the arthroscope is inserted. Adequate distention of the joint is maintained throughout the procedure by a continuous inflow of saline solution introduced into the joint by gravity flow from large fluid bags elevated on an intravenous pole. When required, suction tubing is connected to the arthroscope s outflow connecter to clear debris from the joint. A second, anterior portal may be required for improved inflow or for additional instruments. This second portal is located one-half the distance between the coracoid process and the anterolateral edge of the acromion. The joint is entered in the same manner as through the posterior portal. The spinal needle should enter the capsule just medial to the tendon of the long head of the biceps (hereafter referred to as &dquo;biceps tendon&dquo;); correct placement is aided by direct intraarticular visualization provided by the arthroscope (Fig. 4). A third portal, also anterior, may be established directly adjacent to the initial anterior portal. Through this portal, the spinal needle should enter the capsule just lateral to the biceps tendon (Fig. 5). The instruments may be exchanged between the posterior and anterior portals to improve access to the posterior quadrants of the shoulder joint. Figure 2. The spinal needle is inserted through the posterior portal and directed antenorly toward the coracoid process, which is palpated by the surgeon s index finger. Figure 3. Closely observing the angle of the spinal needle, the arthroscope cannula and sharp trocar are inserted, aimed directly toward the coracoid process.

3 3 Figure 4. The antenor portal is established by inserting the spinal needle one-half of the distance between the anterolateral border of the acromion and the coracoid process. Intraarticular placement is facilitated by direct visualization with arthroscope. glistening and smooth and free of adhesions, fraying, or partial tears. Humeral head and glenoid After the inspection of the biceps tendon is complete and proper orientation is regained, the articular surfaces of the humeral head (superiorly) and the glenoid (inferiorly) are examined. With the patient positioned as described, one can see approximately one-third of the articular surface of the humeral head oriented at 30 of retroversion. Examination of the entire articular surface is facilitated by rotating the arthroscope superiorly and rotating the humeral head into internal and then external rotation. The glenoid, a pearshaped cavity approximately one-fourth the size of the humeral head, should also be examined, keeping in mind that the biceps tendon attaches to the posterosuperior aspect of the glenoid rim. Glenoid labrum The glenoid labrum, the wedge-shaped structure that borders the glenoid cavity, provides inherent stability to the glenohumeral joint and restricts anterior and posterior excursion of the humerus.3~ lo The labrum consists of hyaline cartilage, fibrocartilage, and fibrous tissue.3 5 ~ ~ zo, 23 The glenoid surface of the labrum is continuous with the hyaline cartilage of the glenoid cavity, while the capsular surface blends with the joint capsule. The glenoid labrum should appear smooth and should lack fraying, partial tearing, or hypermobility. Inspection begins at the insertion of the biceps tendon through the superior portion of the labrum into the supraglenoid tubercle and continues anteriorly and inferiorly. Additional distraction of the arm with the traction apparatus will allow examination of the inferior rim. Slight retracting and posterior rotation of the arthroscope will allow examination of the posterior rim. Glenohumeral ligaments The superior, middle, and inferior glenohumeral ligaments (Fig. 6) stabilize the anterior and inferior portions of the joint capsule.4, When viewed arthroscopically, the glenohumeral ligaments are anteriorly displaced due to fluid distension within the shoulder joint. These ligaments normally lie closer to the glenoid labrum. Occasionally, they will be seen to have distinct labral origins rather than their usual capsular origins. The superior glenohumeral ligament, together with the coracohumeral ligament, stabilizes the shoulder when the arm is in the adducted, dependent position.4, 20 The ligament has two proximal attachments: one to the superior aspect of the labrum conjoined with the biceps tendon and one to the base of the coracoid.26 The ligament courses laterally to insert on the anterior aspect of the anatomic neck of the humerus. The superior glenohumeral ligament can usually be seen near the insertion of the biceps tendon into the superior aspect of the glenoid; however, it may be hidden behind the biceps tendon and appear to be absent. The middle glenohumeral ligament stabilizes the glenohumeral joint when the shoulder is abducted to Although the attachments of the ligament are wide, they may be difficult to visualize arthroscopically. However, the middle portion of the ligament can usually be seen just posterior to the subscapularis tendon, with which it sometimes fuses. The ligament extends from just beneath the superior glenohumeral ligament along the anterior border of the glenoid to the junction of the middle and inferior one-third of the glenoid rim. It blends with the capsule of the anteroinferior aspect of the shoulder joint and inserts near the lesser tuberosity over the anterior aspect of the anatomic neck of the humerus. The inferior glenohumeral ligament stabilizes the glenohumeral joint when the arm is abducted to approximately go,.2 This triangular ligament arises from the anteroinferior margin of the labrum and inserts into the inferior aspect of the surgical neck of the humerus. It can be seen arthroscopically when the arm is in abduction. Subscapularis tendon and recess With the arm in the abducted position, the posterosuperior edge of the subscapularis tendon (Fig. 6) can be seen in the anterior aspect of the shoulder between the superior and middle glenohumeral ligaments. The subscapularis tendon may, however, be obscured by or appear to blend with the middle glenohumeral ligament. The subscapularis recess can be found in the anterior aspect of the shoulder joint in the area of the middle glenohumeral ligament (Fig. 8). Rotator cuff Arthroscopic examination of the rotator cuff begins by identifying the biceps tendon and obtaining proper orientation. The supraspinatus tendon can be seen just superior to the biceps tendon. Visualization is facilitated by rotating the arthroscope superiorly and slightly toward the humeral head. Slight posterior retraction of the arthroscope will reveal the insertion of the tendinous portion of the rotator cuff muscles

4 4 Figure 5. A, operative arthroscopy performed with a motorized instrument and an inflow cannula through two anterior portals. The arthroscope is placed posteriorly. B, the anterior instruments are placed medial (A) and lateral (B) to the biceps tendon. The arthroscope enters through the posterior portal (C). into the humeral head (Fig. 9). The infraspinatus and teres minor portions of the rotator cuff can be seen by directing the arthroscope posteriorly and superiorly. Superior recess The superior recess is located superior and slightly anterior to the superior aspect of the glenoid and to the insertion of the biceps tendon. This recess should be examined for abnormality. DISCUSSION Arthroscopic examination of the shoulder must be performed in a methodical fashion to ensure accuracy. We have found that a 4 mm, 30 angled arthroscope allows optimal

5 5 Figure 6. Arthroscopic anatomy of a right shoulder with the arm abducted 70 : (1) tendon, long head of the biceps, (2) superior glenohumeral ligament, (3) subscapularis tendon, (4) middle glenohumeral ligament, and (5) infenor glenohumeral ligament. visualization of the structures within the shoulder joint. Using the biceps tendon as an internal landmark, each anatomical structure should be examined in sequential order as presented: the biceps tendon, the humeral head, the glenoid, the glenoid labrum, the glenohumeral ligaments, the subscapularis tendon and recess, the tendons of the rotator cuff muscles, and the superior recess (Fig. 6). A great deal of variation in the glenohumeral ligaments S 11, has been described.5, Mosely and Overgaard20 found the inferior glenohumeral ligament to be the most consistent of the glenohumeral ligaments in patients in their series, as did Turkel et al.,26 who described a thick &dquo;superior band&dquo; and a smaller &dquo;axillary pouch.&dquo; DePalma et al., however, found the superior glenohumeral ligament to be consistently well-defined in their cadaveric specimens, while the inferior glenohumeral ligament was ill-defined or absent in 44%. In the DePalma group s specimens, the middle glenohumeral ligament was well-defined in 71 % and absent or ill-defined in the remaining 29%. The variable relationship of the glenohumeral ligaments can result in variations in the subscapularis recess. The recess may be found superior or inferior to the middle glenohumeral ligament or both. Or, in the absence of a middle glenohumeral ligament, a single large subscapularis recess may be found. Care should be taken not to misinterpret these variations in the normal anatomy as a pathologic or traumatic disorder. As in other diagnostic modalities, arthroscopic examination of the shoulder must be reproducible and systematic to be effective. The most technically demanding aspect of shoulder arthroscopy is gaining entrance to the glenohumeral joint. Unlike arthroscopy of the knee, in which the instruments traverse only skin, subcutaneous fat, and a thin retinaculum, shoulder arthroscopy requires that the instruments pass through thicker layers of fat and muscle and a thick capsule. Because the glenohumeral joint is located deep to these multiple layers, proper orientation is essential to avoid entrance into the subdeltoid bursa or into the axilla. By outlining the bony landmarks with a pen and by adhering to the technique described here, the arthroscope may be inserted into the shoulder in a safe fashion. The time spent in performing an arthroscopic examination must be monitored. A significant amount of fluid can extravasate through the subscapularis bursa or the bicipital groove. The resultant tissue swelling can present technical difficulties. Extravasation increases the distance between the skin and the entrance into the shoulder capsule. As a result, the instruments can slip out of the capsule easily. Complications such as a musculocutaneous or ulnar nerve neuropraxia can be caused by overdistraction of the glenohumeral joint. Such complications can be avoided, however, by properly positioning the patient s arm as described. In addition, limiting the weight in the traction apparatus to 15 or 20 pounds will distract the articular surface of the humeral head away from the glenoid, yet will not overstretch the brachial plexus. CONCLUSION Diagnostic arthroscopy of the shoulder can be systematic and reproducible when the surgeon is knowledgeable of the normal and normal variational anatomy of the shoulder and when attention is given to accurate placement of the arthroscopic portals and to consistent surgical technique.

6 6 Figure 7. Arthroscopic anatomy of a right shoulder with the arm abducted 70 as seen through the posterior portal: (1) tendon, long head of the biceps, (2) humeral head, (3) subscapularis recess, (4) subscapularis tendon, and (5) middle glenohumeral ligament. Figure 8. Area of the subscapularis tendon in a right shoulder as seen through the posterior portal: (1) tendon, long head of the biceps, (2) humeral head, (3) subscapularis recess, (4) subscapularis tendon, and (5) middle glenohumeral ligament.

7 7 Figure 9. Arthroscopic view in a right shoulder as seen from the posterior portal. The arthroscope is directed inferiorly and superiorly, facilitating visualization of the humeral head: (1) posterosuperior aspect of the humeral head, (2) posterior aspect of the glenoid labrum, (3) inferior recess, and (4) posterior aspect of the rotator cuff. ACKNOWLEDGMENTS This work was supported in part by the Hughston Sports Medicine Foundation, Inc., Columbus, Georgia. The authors wish to thank Slack, Inc., for their permission to reprint material which previously appeared in Orthopaedics 6: , September REFERENCES 1 Andren L, Lundberg BJ Treatment of rigid shoulders by joint distension during arthroscopy Acta Orthop Scand 36, 45-53, Andrews JR, Wilkes JS Arthroscopic surgery in throwing athletes with glenoid labrum tears Presented at the Annual Meeting of the American Orthopaedic Society for Sports Medicine, Lake Tahoe, Nevada, July Bankhart ASB. The pathology and treatment of recurrent dislocation of the shoulder joint Br J Surg , Basmajian JV, Bazant FJ Factors preventing downward dislocation of the adducted shoulder J Bone Joint Surg 41A , Bost FC, Inman VT The pathological changes in recurrent dislocation of the shoulder A report of Bankart s operative procedure J Bone Joint Surg 24A , Braunstein EM, O Bonner G Double-contrast arthrotomography of the shoulder J Bone Joint Surg 64A , Caspan RB Shoulder arthroscopy, a review of the present state of the art Contemp Orthop , DePalma AF, Callery G, Bennett GA Vanational anatomy and degenerative lesions of the shoulder joint In Instructional Course Lectures of the American Academy of Orthopaedic Surgeons , DePalma AF Degenerative lesions of the shoulder joint at various age groups which are compatible with good function In Instructional Course Lectures of the American Academy of Orthopaedic Surgeons , DePalma AF Surgery of the Shoulder Philadelphia, JB Lippincott, Flood V Discovery of a new ligament of the shoulder joint Lancet , Dutoit GT, Roux D Recurrent dislocation of the shoulder A twenty-four year study of the Johannesburg stapling operation J Bone Joint Surg 38A: 1-12, Gray s Anatomy of the Human Body Edition 35, Warwick R, Williams P, (eds), Philadelphia, WB Saunders, Ha en GB, Maitland A Arthroscopic findings in the frozen shoulder J Rheumatology , Johnson LL Arthroscopy of the shoulder Orthop Clin North Am , Johnson LL Diagnostic and Surgical Arthroscopy St Louis, CV Mosby, 1981, pp Lioyd GJJ, Older MW, McIntyre JC Distention arthroscopy of the shoulder joint Can J Surg , Mink JH, Richardson A, Grant TT Evaluation of glenoid labrum by doublecontrast shoulder arthrography Am J Roentgenol , McGlynn FJ, El-Khourg G, Albright JW Arthrotomography of the glenoid labrum in shoulder instability J Bone Joint Surg 64A , Mosely JF, Overgaard The anterior capsular mechanism in recurrent antenor dislocation of the shoulder J Bone Joint Surg 44B , Pappas AM, Goss TP, Kleinman PK Symptomatic shoulder instability due to lesions of the glenoid labrum Presented at the annual meeting of the American Academy of Orthopaedic Surgeons, Anaheim, California, March, Rokous JR, Feagin JR, Abbott JY Modified axillary roentgenogram A useful adjunct in the diagnosis of recurrent instability of the shoulder Clin Orthop , Rowe CR, Patell D, Southmayd WW The Bankhart procedure A longterm, end-results study J Bone Joint Surg 60A 1-6, Rowe DR, Zarins B Recurrent transient subluxation of the shoulder J Bone Joint Surg 63A , Schlemm F Ueber Die Verstarkungsbander am Schultergelenk Arch Anat 45-48, Turkel SJ, Panio MW, Marshall JL, et al Stabilizing mechanism preventing anterior dislocation of the glenohumeral joint J Bone Joint Surg 63A , Weitbrecht J Syndesmology, or, A Description of the Ligaments of the Human Body Translation by E B Kaplan, Philadelphia, WB Saunders, Wiley AM, Older MB Shoulder arthroscopy Investigation with a fibro-optic instrument Am J Sports Med , 1980