Arthroscopic Capsulolabroplasty for Posteroinferior Multidirectional Instability of the Shoulder

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1 DOI = / Arthroscopic Capsulolabroplasty for Posteroinferior Multidirectional Instability of the Shoulder Seung-Ho Kim,* MD, Hyo-Kon Kim, MD, Jong-Il Sun, MD, Jun-Sic Park, MD, and Irvin Oh, MD From the Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea Background: Arthroscopic treatment of posteroinferior multidirectional instability of the shoulder is not well documented. Purpose: To evaluate pathologic lesions of posteroinferior multidirectional instability and the results of arthroscopic capsulolabroplasty. Study Design: Prospective nonrandomized clinical trial. Methods: Thirty-one patients with posteroinferior multidirectional instability were prospectively evaluated after arthroscopic capsulolabroplasty (mean follow-up, 51 months). Labral lesion and height were measured in the MRI arthrogram and arthroscopic examination. Results: All patients had a labral lesion and variable capsular stretching in the posteroinferior aspect. There were 11 type I labral lesions (incomplete detachment), 12 type II (the Kim s lesion: incomplete and concealed avulsion), 6 type III (chondrolabral erosion), and 2 type IV (flap tear). All patients with type II and III lesions had chondrolabral retroversion, with lost labral height in the MRI arthrogram and arthroscopic examination. Twenty-one patients had an excellent Rowe score, nine had good scores, and one had a fair score. Thirty patients had stable shoulders, and one had recurrent instability. All patients had improved shoulder scores and function and pain scores. Conclusions: Symptomatic patients with posteroinferior multidirectional instability had posteroinferior labral lesions, including retroversion of the posteroinferior labrum, which were previously unrecognized. Restoration of the labral buttress and capsular tension by arthroscopic capsulolabroplasty successfully stabilized shoulders with posteroinferior multidirectional instability. Keywords: multidirectional instability; arthroscopy; capsulolabroplasty; outcome; shoulder *Address correspondence to Seung-Ho Kim, MD, Department of Orthopaedic Surgery, Samsung Medical Center, 50 Ilwon-Dong, Kangnam-Ku, Seoul , Korea. No author or related institution has received financial benefit from research in this study. The American Journal of Sports Medicine, Vol. 32, No. 3 DOI: / American Orthopaedic Society for Sports Medicine Although a redundant capsule has been believed to be the main pathologic lesion and the inferior capsular shift procedure has become the standard operation in the management of symptomatic multidirectional instability of the shoulder that does not respond to nonoperative treatment, 4,11,37,39 the entire spectrum of multidirectional instability is not clearly identified. Controversies remain regarding the role of the capsular mechanism versus the glenoid version in the development of multidirectional instability and their role in the distinction between multidirectional laxity and multidirectional instability. Previous authors have reported on mixed groups of patients in the same article, including anteroinferior instability and posteroinferior instability, primary and revision surgeries, and different surgical procedures; therefore, interpretation of the results has been difficult. 4,5,11,20,39,48 Arthroscopic management of symptomatic posteroinferior multidirectional instability has primarily focused on capsular plication or superior shift of the redundant inferior capsule. The results have been promising, although not always satisfactory. 3,15,35,43,45,49 Compared to articles describing open inferior capsular shift, these articles described a more common incidence of labral lesions as well as capsular redundancy in arthroscopic evaluation. Kim et al 30,31 described a concealed labral lesion that had been previously underestimated in traumatic posterior instability. The purpose of this study was to evaluate the underlying lesions of posteroinferior multidirectional instability and to report the results of arthroscopic capsulolabroplasty that included arthroscopic posteroinferior 594

2 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 595 labroplasty, which was performed by creating a complete detachment on the posterior and inferior labrum and reattachment on the glenoid surface; superior shift of the posteroinferior and anteroinferior capsule; and closure of the rotator interval. MATERIALS AND METHODS Patient Selection Since September 1995, we have performed arthroscopic treatment for patients with multidirectional or posterior instability. In this prospective analysis, we selected patients with posteroinferior multidirectional instability who were treated between May 1997 and February 2000 and met the following criteria: (1) the instability was symptomatic in more than 1 direction, (2) the patient had a positive jerk test 6 with a painful clunking of the shoulder, (3) there were no Bankart lesions on the MRI arthrogram or arthroscopic examination, (4) the sulcus sign 37 was positive, and (5) nonoperative treatments failed for at least 6 months. The patients symptoms included shoulder pain, fatigue, and paresthesia or looseness during daily or sports activities such as carrying heavy loads, overhead movements, throwing, or swimming. The direction of instability was assessed by simulating an attempted subluxation maneuver. For the anterior direction, anteriorly directed force was exerted on the posterior aspect of the humeral head while the arm was in an adducted position in a sitting position as well as in 90 abduction and an external rotation position in a supine position (fulcrum test 8 ). Increased translation with pain was considered positive instability. For the inferior direction, downward force was applied on the adducted arm. Translation with simultaneous generation of pain was considered symptomatic. For the posterior direction, a jerk test was used. With the involved arm holding at 90 abduction, simultaneous horizontal adduction and posteriorly directed axial loading applied to the glenohumeral joint produced a sudden palpable or an audible clunk as well as pain. The sulcus sign 37 was measured by inferior translation. A downward traction force was applied to the adducted shoulder, and the inferior translation of the humerus was measured by estimating the distance between the inferior margin of the lateral acromion and the humeral head: 0+ was equivalent to no movement, 1+ to less than 1 cm movement, 2+ to 1 to 2 cm movement, and 3+ to more than 2 cm movement. Nonoperative treatment consisted of extensive rehabilitation including strengthening exercises of the rotator cuff, deltoid, and scapular stabilizer muscles. The majority of the patients with multidirectional hyperlaxity and many of the patients with multidirectional instability responded to the extensive rehabilitation program and were not included in this study. The patients who responded best to the nonoperative treatments were the group who had hyperlaxity and young females with spontaneous onset of mild symptoms. These patients had improvement of symptoms and returned to their activities, although hyperlaxity remained. This study included a small proportion of patients who failed nonoperative treatments for at least 6 months. We excluded patients who had traumatic unidirectional posterior instability, which we previously reported 30 ; traumatic anterior or anteroinferior instability with a Bankart lesion; revision surgery; or previous surgery on the same shoulder. Thirty-four patients were treated during the index period, and three were lost to follow-up within 2 years. One patient returned to his home country, and two could not be contacted at all. Therefore, this study included 31 patients who were followed up for a mean of 51 months (range, months). The institutional review board of our center approved the study, and each patient signed a detailed informed-consent form. Surgical Technique We performed the so-called arthroscopic capsulolabroplasty procedure, which is a battery of 3 major procedures including arthroscopic posteroinferior labroplasty, superior shift of the posteroinferior and anteroinferior capsule, and rotator interval closure. Posteroinferior Labroplasty The basic rationale of the posteroinferior labroplasty was restoration of the posteroinferior labral height and capsular tension. We used general anesthesia and a lateral decubitus position for all patients. The arm was maintained in lateral traction at 30 abduction and 10 forward flexion. After the surface landmarks drawing, the posterior portal was created 2 cm inferior to the posterolateral acromial angle. This point was about 1 cm lateral to the standard posterior glenohumeral portal and provided a proper angle to the posteroinferior labrum and capsule. Two anterior portals were created just below the acromioclavicular joint (anterosuperior portal) and above the leading edge of the subscapularis (anterior midglenoid portals) while maintaining at least a 1-cm distance between the 2 anterior portals. We used a large clear-threaded cannula (Linvatec, Largo, Fla) for posterior and anterior midglenoid portals and a small nonthreaded cannula (Universal cannula, Linvatec) for the anterosuperior portal. From both posterior and anterior portals, diagnostic arthroscopy was performed while focusing on the posteroinferior labrum and capsule. Associated lesions were treated first. Partial-thickness tears of the articular surface of the rotator cuff tendon were debrided. While viewing from the anterior superior portal, a loose flap of the posteroinferior labrum, if encountered, was debrided. The posteroinferior labral lesion was visualized well through the anterosuperior portal. Palpation of the posteroinferior labrum was mandatory because the tear of the posteroinferior labrum sometimes existed at the deep portion of the labrum, whereas the chondrolabral junction had chondrolabral erosion or superficial cracks, which apparently mimic intact attachment 30,31 (Figure 1A). Probing revealed looseness of the posteroinferior labrum. When the superfi-

3 596 Kim et al The American Journal of Sports Medicine Figure 1. Posteroinferior labroplasty. A, the chondrolabral junction has a superficial crack that apparently mimics intact attachment. B, the posteroinferior labrum was mobilized until it was easily movable on the glenoid surface with a blunt grasper. C, a 90 -angled suture hook, which was loaded with Shuttle-Relay, was introduced through the posterior portal, piercing the posterior band of the inferior glenohumeral ligament at the same level of the glenoid. D, the suture was shifted about 1 cm proximally, and then it was passed under the posteroinferior labrum. E, the Shuttle-Relay was retrieved out of the anterior midglenoid portal. The suture was loaded into the eyelet of the Shuttle-Relay and pulled back out of the posterior portal. F, an arthroscopic knot tying (the SMC knot) was performed. One to three suture anchors were used for labroplasty.

4 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 597 Figure 2. Superior shift of the posteroinferior labrum. A, the suture hook pierced the posterior capsule and was shifted superiorly about 1 cm to pass under the labrum. The Shuttle-Relay with the suture was pulled back through the anterior midglenoid portal. B, sutures were placed and tied successively to achieve a superior capsular shift until the most superior suture was placed at the level of the biceps insertion. cial portion of chondrolabral junction was detached by the Liberator knife (Linvatec), the loose, deep portion was easily palpated. The posteroinferior labrum was completely detached from the glenoid using the Liberator and motorized shaver. We exposed the underlying muscle to achieve proper mobility until the posterior and inferior labrum was easily brought up on the glenoid surface with a blunt grasper (Figure 1B). A small meniscal rasp (Linvatec) was introduced through the posterior portal to abrade the inferior and posterior glenoid wall. The glenoid wall was freshened by a shaver (full radius resector), and the fresh bony surface was exposed. Inferior and posterior capsules were abraded to enhance the healing potential using a convex rasp (Linvatec). A small pilot marking was created on the glenoid rim using a small pituitary forceps, which was introduced through the posterior portal. A bone punch was introduced and aimed at the medial end of the pilot marking to create an anchor hole on the surface 2 mm from the margin of the glenoid. A suture anchor (Mini-Revo, Linvatec) with number 2 nonabsorbable sutures (Ethibond, Ethicone, Somerville, NJ) was fixed while maintaining the orientation of the eyelet. One end of the suture, which was closer to the capsule, was retrieved out of the anterior midglenoid portal. A 90 -angled suture hook, which was loaded with the Shuttle-Relay (Linvatec), was introduced through the posterior portal, piercing the inferior capsule at the same level of the glenoid (Figure 1C). The suture was shifted about 1 cm proximally; it was then passed under the posteroinferior labrum (Figure 1D). The Shuttle-Relay was retrieved out of the anterior midglenoid portal. The suture was loaded into the eyelet of the Shuttle-Relay and pulled back out of the posterior portal (Figure 1E). An arthroscopic knot tying was performed. We used the SMC knot, which was a sliding knot and had an internal locking mechanism. 28,29 Three to six suture anchors were used for labroplasty depending on the size of the labral lesion (Figure 1F). Superior Shift of the Posteroinferior and Anteroinferior Capsule After completion of the posteroinferior labroplasty, superior shift of the posterior capsule was performed. The suture hook pierced the posterior capsule at the same level of the glenoid surface to avoid taking the lateral capsule. The suture hook was shifted superiorly about 1 cm and then passed under the labrum. The Shuttle-Relay was retrieved through the anterosuperior portal, and a number 2 nonabsorbable suture was engaged in the eyelet of the Shuttle- Relay. The Shuttle-Relay with the suture was pulled back through the anterior midglenoid portal (Figure 2A), and the SMC knot tying was performed. Sutures were placed and tied successively to achieve a superior capsular shift until the most superior suture was placed at the level of the biceps insertion (Figure 2B). For the shift of the anteroinferior capsule, the arthroscope was inserted through the posterior portal. Inferior and anterior capsules as well as the corresponding glenoid labrum were abraded using the arthroscopic rasp. The suture hook was introduced through the anterior midglenoid portal, piercing the inferior capsule 1 cm away from the labrum. When simultaneous passage of the suture hook through the inferior capsule and the labrum was difficult, 2 steps were performed separately. The suture hook was shifted and passed under the labrum to make a knot tying, and proximal shift of the inferior capsule was repeated in 1-cm distances between each suture until the last suture ended at the anterior base of the biceps root (Figure 3).

5 598 Kim et al The American Journal of Sports Medicine Figure 3. Superior shift of the anteroinferior capsule. A, the suture hook pierced the inferior capsule 1 cm away from the labrum; B, the suture hook was shifted and passed under the labrum; C, the suture was retrieved with the Shuttle-Relay; D, proximal shift of the inferior capsule was repeated in 1-cm distances between each suture until the last suture ended at the anterior base of the biceps root. Rotator Interval Closure To perform arthroscopic closure of the rotator interval, the arthroscope was maintained in the posterior portal while the anterior midglenoid cannula was retrieved slightly out of the capsule. A penetrating suture retriever (Mitek, Johnson and Johnson, Somerville, NJ) loaded with a number 2 nonabsorbable suture (Ethibond, Ethicone) was introduced through the anterior midglenoid cannula to pierce the anterior capsule and middle glenohumeral ligament (capsular tissue overlying the superior edge of the subscapularis tendon). Another penetrating suture retriever was inserted into the joint through the anterosuperior cannula. The cannula and suture retriever were then slowly withdrawn from the joint to lie just anterior to the capsule. The penetrating suture retriever pierced the superior capsule. The suture in the penetrating suture retriever of the anterior midglenoid cannula was handed out to the other suture retriever. One or two additional sutures were repeated in the same manner using sutures with different colors. In a blind manner, 1 end of the suture in either portal was passed to the other portal under the deltoid muscle, and the SMC sliding knots 28,29 were created while maintaining the arm in about 40 abduction and 30 external rotation (Figure 4). A catheter for the self-controlled pain pump (Accufuser, Woo Young Medical, Seoul, Korea) was inserted through the anterior skin with the aid of the spinal needle. Decision Making for the Selection of Subset of Arthroscopic Capsulolabroplasty We were able to perform both anterior and posterior procedures by the same arthroscopic approach through the same 3 arthroscopic portals. Within the 3 subsets of the arthroscopic capsulolabroplasty procedure, we used pos-

6 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 599 Figure 4. Closure of the rotator interval. A, a penetrating suture retriever with a number 2 nonabsorbable suture was introduced through the anterior midglenoid cannula to pierce the anterior capsule and middle glenohumeral ligament. Another penetrating suture retriever in the anterosuperior cannula pierced the superior capsule. The suture in the penetrating suture retriever of the anterior midglenoid cannula was handed out to the other suture retriever. B, one or two additional sutures were repeated in the same manner using sutures with different colors. C, by directly viewing from the subacromial portal or in a blind manner, 1 end of the suture in either portal was passed to the other portal under the deltoid muscle, and the SMC sliding knots were created while maintaining the arm in about 40 abduction and 30 external rotation. TABLE 1 Decision Making for the Selection of Subset of Arthroscopic Capsulolabroplasty Finding Anterior Predominant Jerk Test Sulcus Translation Instability Procedure + 1+ Posterior Labroplasty and capsular shift (posterior) Posteroinferior Labroplasty and capsular shift (posterior and inferior) Inferior Labroplasty, capsular shift (posterior, inferior, and anterior), and rotator interval closure teroinferior labroplasty and superior shift of the posteroinferior and anteroinferior capsules when posterior instability was more predominant than inferior instability (positive jerk test and grade 1+ or 2+ sulcus sign), regardless of the degree of anterior translation if the anterior translation was asymptomatic. All 3 sets of the arthroscopic capsulolabroplasty procedure, including rotator interval closure, were performed when inferior instability was more predominant than the posterior component (positive jerk test and grade 3+ sulcus sign) (Table 1). Postoperative Rehabilitation We used a sling immobilizer (K-sling, Eugene Medical, Seoul, Korea), which kept the shoulder in about 30 abduction and neutral rotation for 3 weeks. The arm was maintained posterior to the longitudinal axis of the trunk. Isometric strengthening exercises were performed with the aid of the contralateral arm. After 3 weeks, a pendulum and active-assisted range-of-motion exercises were initiated, including forward elevation in the scapular plane and

7 600 Kim et al The American Journal of Sports Medicine TABLE 2 Kim et al Classification of the Posteroinferior Labral Lesion Based on Arthroscopic Findings and MRI Arthrogram Type Finding MRI Arthrogram Finding I Incomplete stripping Type I: separation without displacement II Marginal crack Type II: incomplete avulsion III Chondrolabral erosion Type III: loss of contour IV Flap tear Type III: loss of contour external rotation exercises with the arm at the side. After 4 weeks, internal rotation behind the back was initiated. Internal rotation with the elevated arm (cross body adduction position) was prohibited until 6 weeks. After 6 weeks, internal rotation motion with the arm elevated and strengthening exercises were initiated. When the shoulder had regained strength by the manual strength test (above 4 positive), we allowed patients in professional and collegiatelevel sports to do more vigorous strength exercises. Sports activities were allowed after 4 to 6 months depending on the isokinetic measurement (more than 80% of the contralateral side for forward elevation, external rotation at the side, and internal rotation in 90 abduction) using the Cybex 6000 dynamometer (Cybex International, Medway, Mass). Evaluation The patients were asked for their history of trauma prior to the onset of the instability, whether the onset was acute or insidious, and their level of sports activity. Before the operation and at the time of the final follow-up, we evaluated active and passive range of motion, manual muscle testing, generalized ligamentous laxity, 8,19 the impingement sign (Neer 36 and Hawkins sign 8 ), and anterior instability test (fulcrum test 8 ), jerk test, 6 and sulcus sign. 37 For outcome measurement, we used 3 objective shoulder scores (the University of California at Los Angeles [UCLA] scoring system, 16 the American Shoulder and Elbow Surgeons [ASES] Standardized Shoulder Assessment, 40 and the Rowe score 41 ) and 2 subjective measurements (pain 42 and function 27,30 visual analog scales). The visual analog scale 42 is widely used as a self-report measure of pain. The scale consists of a 100-mm line that pictorially represents 2 behavioral extremes at either end of a continuum: no pain (score of 0) and extreme pain (score of 100). Subjective measurement of shoulder function was evaluated using a modified method from Kim et al. 27,30 The generalized ligamentous laxity was defined if patients had 2 of the following signs: thumb-to-forearm distance of 4 cm, index metacarpophalangeal extension in excess of 90, elbow hyperextension, knee hyperextension, or patellar hypermobility. 3,20 Figure 5. Measurement of the glenoid version on the MRI arthrogram. The glenoid version is an angle formed by a tangential line from the center of the glenoid (a) and a line connecting the apex of the anterior and posterior labra (b). Radiographic examinations included anteroposterior, axillary lateral plane, and inferior stress radiographs. Inferior stress anteroposterior radiographs were obtained in the standing position with a 10-lb weight applied downward on both arms. 36 T1-weighted and T2-weighted axial and coronal images of the MRI arthrogram using the intraarticular gadolinium were obtained. Posteroinferior labral lesion was classified using the classification system of Kim et al 30 (Table 2). The glenoid version was measured in the axial images of the MRI arthrogram using the method of previous studies. 9,46 We measured the chondrolabral glenoid version, which incorporated the effects of the articular cartilage and glenoid labrum. This measurement was obtained at the inferior one-third level (5 o clock for the right and 7 o clock for the left shoulder). A reference line drawn through the midpoint of the transverse glenoid diameter at the level of the articular surface and the medial rim of the scapular blade defined the axis of the scapula. The angle between a line perpendicular to this reference line and a line drawn through the anterior and posterior glenoid labrum formed the version of the chondrolabral glenoid (Figure 5). Positive angles represented retroversion, and negative angles represented anteversion. To assess the intraobserver repeatability, the measurements were repeated twice for all patients at different dates. All measurements were performed on the PACS (Picture Archiving and Communications System, General Electric, Chicago, Ill) monitor using a mouse point cursor and automated computer calculation of the angle and length. The chondrolabral glenoid version of the patients with type II and III lesions was compared with that of 33 shoulders without shoulder instability.

8 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 601 Anterior and posterior translations of the humeral head were graded based on Altchek et al. 1 Examination under anesthesia was performed with the patient in the lateral decubitus position. Anteroposterior humeral translation was rated as grade 0 (no translation), grade 1+ (translation less than the margin of glenoid), grade 2+ (translation beyond the margin of glenoid with spontaneous reduction), or grade 3+ (translation beyond the glenoid without spontaneous reduction). 1 Arthroscopic evaluation was performed viewing from the posterior and anterosuperior portals. The posteroinferior labrum was palpated and visually evaluated for its height maintenance (height +, height 0, height ). Height + represented maintenance of the posteroinferior labral height, height 0 meant flat posteroinferior labrum with loss of its height, and height designated further loss of labral height, which became reversal of its height. Height 0 and suggested retroversion of the posteroinferior labrum. Statistical Analysis We used the paired sample t test to compare the preoperative and follow-up ranges of motion. The Wilcoxon signed rank test was used to evaluate preoperative and follow-up shoulder scores and pain and function scores. Using the t test, the version of the chondrolabral glenoid was compared between shoulders with posteroinferior multidirectional instability and the control group. Correlation of labral height between the MRI arthrogram and arthroscopic evaluation was performed (Pearson s correlation coefficient). Differences in results between patients with incomplete labral tears and chondrolabral retroversion were evaluated (Mann-Whitney U test). Statistical analyses were performed with the alpha value set at.05. RESULTS Patient Demographics There were 27 male and 4 female patients with a mean age of 23 years (range, years; SD = 2.7 years). The dominant extremity was involved in 21 patients. Fourteen were sports athletes, and eleven were involved in regular sports activities. Six patients participated in sports on an intermittent basis. Seventeen patients had a history of minor trauma prior to the onset of symptoms. However, the trauma was not significant in nature (ie, did not require immediate medical attention or termination of activities). All patients were positive in the sulcus sign. Twenty-two patients had ligamentous laxity by our criteria. The predominant direction of instability was posterior and inferior in all patients. Twenty patients had more prominent posterior symptoms, and eleven had more prominent inferior symptoms. Six patients had asymptomatic anterior translation (painless translation on the anterior load-shift test greater than 2+). However, these 6 patients were negative in the anterior apprehension test (negative fulcrum test). All patients had recurrent subluxation, and none of the patients had a locked dislocation requiring manipulation. All patients had pain with clunk on the jerk test. Nineteen patients had pain on direct inferior traction of the adducted arm (sulcus maneuver). None of the patients had pain or apprehension on the anterior instability tests, either on the anterior translation test or the anterior apprehension test, although six patients had marked anterior translation greater than grade 2+ using the classification of Altchek et al. 1 Four patients could voluntarily demonstrate shoulder subluxation by muscular contraction. These patients did not have a history of trauma and insidiously learned to voluntarily subluxate in the posteroinferior direction. There were another 4 patients who could demonstrate shoulder subluxation by arm positioning in horizontal adduction of the 90 elevated arm. Radiographic Findings All patients had normal findings on anteroposterior and axial plane radiographs. Inferior stress images showed marked inferior translation of the humeral head on both shoulders. However, the symptomatic shoulder had increased inferior translation in comparison to the asymptomatic side (mean = 34 mm for the lesion side versus 18 mm for the asymptomatic side from the reference line at the inferior aspect of the glenoid on anteroposterior plane radiographs) (P =.014). There was no bony lesion on the posterior or inferior aspect of the glenoid on the axial and anteroposterior plane radiographs. The MRI arthrogram showed 3 types of labral lesion according to the classification of Kim et al 30 : type I, separation without displacement in 9 patients; type II, incomplete avulsion in 5 patients; and type III, loss of contour in 11 patients. Six patients showed a normal labral attachment. All patients had loss of glenoid height, which resulted in retroversion of the chondrolabral glenoid (Figures 6A-C). The labral lesion was distinctive on the coronal images in shoulders with predominant inferior instability (Figure 6D). The chondrolabral glenoid version had a mean of +7.0 retroversion (95% confidence interval, +8.8 to +5.3 ) in patients with type II and type III lesions, whereas the control group of MRI measurements had a mean of +2.3 retroversion (95% confidence interval, +2.9 to +1.7 ) (P =.021). All patients had an enlarged inferior axillary pouch with or without enlargement of the posterior capsule on the MRI arthrogram. Although it is difficult to assess the enlargement of the anterior capsule due to the lack of controls, the anterior capsule also appeared to be enlarged. Arthroscopic Findings All patients had a labral lesion in the posterior and inferior portion of the glenoid. According to the arthroscopic classification of Kim et al, 30 there were 11 (36%) type I labral lesions (incomplete detachment), 12 (39%) type II lesions (marginal crack or Kim s lesion: incomplete and

9 602 Kim et al The American Journal of Sports Medicine Figure 6. Three types of posteroinferior labral lesion on the MRI arthrogram. A, type I: separation without displacement; B, type II: incomplete avulsion; C, type III: loss of contour. D, inferior labrum shows type I tear. concealed avulsion of posteroinferior labrum), 6 (19%) type III lesions (chondrolabral erosion), and 2 (6%) type IV lesions (flap tear) (Figure 7). Type II and III lesions had chondrolabral retroversion, although they appeared to be attached intact. The gross appearance of the posteroinferior labrum was height 0 in 11 patients and height in 7 patients. There was invariably a superficial crack or marginal erosion. Palpation with a probe revealed that the labrum was loose in the deep portion (Figure 8). The location of these labral lesions corresponded with the direction of the symptomatic instability of the shoulder. Predominant inferior instability had an inferior labral lesion, and predominant posterior instability showed a posterior labral lesion. The version of the chondrolabral glenoid on the MRI arthrogram correlated with the height of the posteroinferior labrum in the arthroscopic evaluation (Pearson s correlation coefficient r = 0.652; P =.032). The greater the retroversion on the MRI arthrogram, the greater the negative height on arthroscopic examination. The joint capsule was wavy in appearance and hemorrhagic in the posteroinferior aspect, which suggests variable capsular stretching. One patient had an associated tear in the glenoid insertion of the middle glenohumeral ligament as well as a posteroinferior labral tear (type I lesion). Another patient had a tear of the posterior capsule at the humeral insertion (reverse humeral avulsion of glenohumeral ligament lesion). Three patients had an

10 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 603 Figure 7. Arthroscopic classification of the posterior and inferior labral lesions. A, type I: incomplete detachment; B, type II: marginal crack or Kim s lesion; C, type III: chondrolabral erosion; D, type IV: flap tear. Ellman grade I articular surface partial-thickness rotator cuff tear in the supraspinatus tendon. Follow-up Outcomes Figure 8. Palpation with a probe reveals that the deep portion of the inferior labrum is loose. Thirty patients (97%) had stable shoulders, and one patient (3%) had recurrent instability. The jerk test was converted to negative in all patients except 1 who had recurrent instability. The sulcus sign was converted to 0+ in 26 patients and grade 1+ in 5 patients. However, patients with a grade 1+ sulcus sign did not have symptoms of instability on the jerk and inferior translation tests or in daily and sports activities. One patient who had postoperative recurrence had a symptomatic grade 2+ sulcus sign. Shoulder scores were improved from 41 ± 12 to 91 ± 10 on the Rowe scale, 79 ± 9 to 95 ± 5 for the ASES score, and 24 ± 3 to 33 ± 2 for the UCLA score (Wilcoxon signed rank test, P <.001). Twenty-one patients had an excellent Rowe score, nine had a good Rowe score, and one had a fair Rowe

11 604 Kim et al The American Journal of Sports Medicine score. All patients had improved shoulder function and pain scores after surgery (Wilcoxon signed rank test, P <.001). Twenty-eight patients (90%) returned to more than 90% of previous activity (Table 3). There was a 2 (0-10 ) loss of external rotation and 1 level (0-6 level) vertebral loss of internal rotation (paired t test, P <.05). There was no difference in results between patients with an incomplete labral tear (type I lesion) and chondrolabral retroversion (type II, III, and IV lesions) (Mann-Whitney U test, P >.05). There were no surgical complications such as infection, hardware problems, or neurovascular compromise. DISCUSSION TABLE 3 Clinical Outcome (P <. 001) Preoperative, Follow-up, Variable 95% CI 95% CI Mean shoulder score (points) UCLA a 24 ± 3 (23-25) 33 ± 2 (32-34) ASES b 79 ± 9 (76-82) 95 ± 5 (92-97) Rowe c 41 ± 12 (37-45) 91 ± 10 (88-95) Mean pain score 4.9 ± 1.8 ( ) 0.3 ± 0.5 ( ) Mean activity return (%) 40 ± 19 (33-46) 93 ± 7 (90-95) a The rating system of the University of California at Los Angeles. 16 b The American Shoulder and Elbow Surgeons Shoulder Index. 39 c The rating system of Rowe et al. 40 Previously, the general consensus was that loose capsular ligament was the main pathologic lesion for posteroinferior multidirectional instability and inferior capsular shift as a surgical treatment had rationale support. However, not only did our study demonstrate capsular redundancy as a main lesion of posteroinferior multidirectional instability, but also the labral lesions, either distinct tears or chondrolabral retroversion, were invariable pathologic lesions that were closely associated with posteroinferior multidirectional instability. These findings support the theoretical rationale of capsulolabroplasty, which restores the labral height and capsular tension. In 1980, Neer and Foster 36 introduced a new type of capsular procedure, which they termed inferior capsular shift, for the reconstruction of multidirectional instability. They approached either the posterior or anterior direction depending on the direction of the instability in which the shoulder was most unstable. The principle of inferior capsular shift was to detach the capsule from the neck of the humerus and shift it to the opposite side of the calca (inferior portion of the neck of the humerus) to not only obliterate the inferior pouch and capsular redundancy on the side of the surgical approach but also to reduce laxity on the opposite side. Subsequent studies generally supported the original Neer and Foster description, 4,14,33,39 although the results are not uniformly successful. 23 However, despite many reports on arthroscopic stabilization of the traumatic anterior instability, only a limited number of studies are available in the peer-reviewed literature concerning arthroscopic treatment of posteroinferior multidirectional instability. 15,35,45 Duncan and Savoie 15 reported their preliminary results of 10 patients who were treated with arthroscopic modification of the inferior capsular shift procedure described by Altchek et al. 1 In 1 to 3 years of follow-up, all patients had satisfactory results according to the Neer system. McIntyre et al 35 reported the results of the modified transglenoid, multiple-suture technique described by Caspari. Nineteen consecutive patients were successful at a mean follow-up of 34 months, except for 1 patient who had recurrent anterior subluxation. Treacy et al 45 reported on a retrospective study of 25 patients who underwent arthroscopic capsular shift performed with the transglenoid technique. At a mean followup of 60 months, they had 22 patients with stable shoulders and full range-of-motion. Overall, the results were successful in 88% to 100% of patients. No further backup clinical study has yet been published, but there are many articles on the thermal capsular shrinkage procedure. 2,10,17,26 A review of previous literature discloses that there is no consensus on the distinction between the posteroinferior and anteroinferior multidirectional instability. Pathologic lesions vary including Bankart lesion, Hill-Sachs lesion, reverse Bankart lesion, and capsular redundancy. Therefore, it is difficult to directly compare the outcome of 1 surgery to another. The current study focused on multidirectional instability with a predominant posteroinferior component. Previous literature reported infrequent incidence of labral lesion in posteroinferior multidirectional instability. However, in our observation, the posterior and inferior labrum was abnormal in all patients. Eleven patients (36%) had frank tear of the posteroinferior labrum from the glenoid; two patients had flap tear. These types of reverse Bankart lesions were easy to identify with arthroscopic observation. However, the remaining types of labral lesions type II and III lesions can be easily overlooked by visual observation alone. In particular, the type II lesion, the Kim s lesion, appears to have only a marginal crack. However, the posteroinferior labrum of this lesion loses its normal height and becomes a flat or retroversed labrum. Careful probing reveals a supple posteroinferior labrum suggesting that the deep portion is already loose. A superficial incision of 1 or 2 mm over the marginal crack discloses a concealed avulsion of the deep portion. The inferior part of the normal labrum is usually a rounded, elevated fibrous structure that is firmly continuous with the articular cartilage. 13 The dimension of the posteroinferior labrum is not substantially different from that of the anteroinferior labrum. 13 Therefore, the loss of height in the retroversed labrum should be corrected during surgery because the glenoid labrum is responsible for the mechanical stability of the glenohumeral joint, and References 1, 3, 4, 11, 14, 15, 20, 23, 35, 37, 39, 44, 45, 47, 49.

12 Vol. 32, No. 3, 2004 Arthroscopic Capsulolabroplasty 605 increasing the effective glenoid depth leads to a substantial increase in the mechanical stability of the glenohumeral joint. 32,34 The marginal crack in posteroinferior instability is different from similar lesions, which are often incidentally found in other conditions such as degenerative arthritis or rotator cuff disease. Therefore, the marginal crack itself is not a hallmark of posteroinferior instability. Symptomatic posterior and inferior subluxation with a positive jerk test (painful clunking) should accompany it to make a diagnosis of posteroinferior instability. Also, the Kim s lesion is different from the anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion 38 of the traumatic anterior instability. The ALPSA lesion is a complete tear of labrum, which is displaced and attached to the medial wall of glenoid by scar tissue. 38 Kim s lesion in this study is not grossly displaced. Retroversion of the posteroinferior glenoid labrum was verified by MRI arthrogram as well. The face of the glenoid significantly tilted toward the posterior direction, if we count the labrum as a whole glenoid. Previous attempts to measure the glenoid version have focused on the bony architecture, which was evaluated on computed tomography or MRI. 5,9,18,21,22,25,46 Brewer et al 9 reported excessive retroversion of the bony glenoid cavity to be the primary etiology of the instability; they have successfully stabilized the shoulders by correcting the deformity by glenoplasty. However, others did not find glenoid retroversion in posteroinferior multidirectional instability patients. 5 Also, the reported values for glenoid version vary widely 7,12,18 ;as seen in a recent study, the measured glenoid version ranges from 9.5 of anteversion to 10.5 of retroversion. 12 Indeed, static stability of the glenohumeral joint is a function of the humeral head and entire glenoid. 24,32 Articular cartilage and the labrum as a whole reinforce and deepen the otherwise nonconcentric and shallow bony glenoid to form a well-constrained ball-and-socket joint. Therefore, the version of glenohumeral joints can be more practically evaluated if the glenoid labrum is included on the MRI arthrogram. At this moment, it is unclear whether the retroversion of the posteroinferior labrum is of developmental origin or if there is a secondary phenomenon of repetitive subluxation of the humeral head. Because the posteroinferior capsule attaches to the inferior portion of the posteroinferior labrum, the posterior and inferior forces initially exert on the inferior portion of the posteroinferior labrum, and tears initiate from the deep portion of the labrum. Because the magnitude of the posteroinferior-directed force in the posteroinferior subluxation is less severe than that of the anterior instability, the deep portion tear can be limited within the labrum without propagating to the superior portion of the chondrolabral junction. Also, excessive rim loading of the humeral head on the posteroinferior labrum during repetitive subluxation produces shear force between the bony glenoid and the labrum. With repetitive episodes of the subluxation of the humeral head, frequent movement of the concealed avulsion creates a marginal crack in the chondrolabral junction (Figure 9). Therefore, Figure 9. Hypothesis of the Kim s lesion. The posterior force initially exerts on the medial portion of the posteroinferior labrum, and tears initiate from the inner portion of the labrum. Excessive rim loading of the humeral head on the posteroinferior labrum during repetitive subluxation produces shear force between the bony glenoid and the labrum. With repetitive episodes of subluxation of the humeral head, frequent movement of the concealed avulsion creates a marginal crack in the chondrolabral junction and concealed avulsion. the triad of the Kim s lesion consists of marginal crack or erosion, chondrolabral retroversion, and incomplete and concealed avulsion. The clinical significance of the Kim s lesion is that retroversion should be corrected by conversion of the concealed lesion into a complete tear and reattachment on the surface of the glenoid to create labral height. If the Kim s lesion is not properly addressed, a simple capsular plication can result in less-than-perfect restoration of the labral height and persistent looseness of the labral attachment. In the current study, labroplasty is a reconstructive procedure that restores posteroinferior labral buttress as well as appropriate capsular tension. A key procedure is a complete mobilization of the posteroinferior labrum until the underlying muscle is completely exposed and the mobilized labrum can be easily brought over the glenoid. Nevertheless, we do not believe that the labral lesion alone is entirely responsible for the instability in our patients. Associated capsular redundancy and labral lesions play concomitant roles in the development of posteroinferior multidirectional instability. Therefore, the surgical procedure in these patients should involve both the repair of the loose labrum and tightening of the capsular redundancy at the same time. The results of the present study are comparable to or better than those of other inferior capsular shift proce-

13 606 Kim et al The American Journal of Sports Medicine dures in subjective and objective measurements. Previous reports on the outcomes of surgical procedures are not straightforward, with the recurrence rate ranging from 3% to 40% 3,4,11,17,23,26,39,48 and having mixed patient groups, including primary and revision surgeries. 37 However, the patient groups in previous studies are different from ours in that previous studies included patients with anterior Bankart lesions as well as multidirectional instability with a posteroinferior component. Our study had posterior and inferior direction of instability in all patients; only 6 had concomitant increased translation in the anterior direction. We believe that the increased translation in the anterior direction in these patients is more likely asymptomatic laxity, which is not related to shoulder symptoms during their daily activities or sports. However, we performed a superior shift of the anteroinferior capsule to balance the posterior capsular shift. Otherwise, unopposed anterior translation after posterior tightening may cause symptomatic anterior laxity. Also, patients in the current study included primarily male patients, which is contrary to many studies 11,14,36,48 and similar to others. 4,23,45 This is because a majority of our female patients with multidirectional instability were successfully treated by nonoperative rehabilitation. This study includes a large number of patients from a homogenous group with posteroinferior multidirectional instability in the predominant posterior and inferior direction. We instituted a prospective analysis of data of a single surgeon s consecutive patients. Also, this study reports on a new type of pathologic lesion of posteroinferior multidirectional instability and presents a new surgical technique based on our arthroscopic and radiographic findings. A drawback of this study is the absence of patients from the control group. In conclusion, labral lesions are invariably associated with posteroinferior multidirectional instability, which requires surgical intervention. The retroversion of the Kim s lesion should be corrected by arthroscopic labroplasty. Arthroscopic capsulolabroplasty is a reliable procedure for posteroinferior multidirectional instability. REFERENCES 1. Altchek DW, Warren RF, Skyhar MJ, et al. T-plasty modification of the Bankart procedure for multidirectional instability of the anterior and inferior types. J Bone Joint Surg Am. 1991;73: Anderson K, Warren RF, Altchek DW, et al. Risk factors for early failure after thermal capsulorrhaphy. Am J Sports Med. 2002;30: Antoniou J, Duckworth DT, Harryman DT II. Capsulolabral augmentation for the management of posteroinferior instability of the shoulder. J Bone Joint Surg Am. 2000;82: Bak K, Spring BJ, Henderson JP. 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