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Arthroscopic subacromial decompression: A clinical review
Arthroscopy:
The Journal of Arthroscopic
and Related Surgery
Published by Raven Press, Ltd. 0 1992 Arthroscopy
Arthroscopic
8(2):141-147
Association of North America
Subacromial Decompression: . Clinical Review
A
Richard K. N. Ryu, M.D.
Summary: Arthroscopic subacromial decompression has become a popular technique supplanting the open Neer acromioplasty in many instances of chronic rotator cuff disease. A review of 61 consecutive decompressions with a minimum follow-up of 12 months was undertaken to evaluate preoperative criteria and surgical outcomes. Of the 61 patients, 53 patients with an average follow-up of 23 months were available for review. Thirty-four men and 19 women with an average age of 47 years comprised the study group. Eleven (21%) had full-thickness tears, 35 (66%) had partial-thickness injuries, and 7 (13%) had normal-appearing rotator cuffs at the time of arthroscopy. The UCLA shoulder rating system was used to evaluate outcome. Eighty-one percent of the patients had an excellent (32%) or good (49%) result whereas 19% (15% fair and 4% poor) were considered unsatisfactory. Those with early impingement findings and partial rotator cuff tears were likely to experience a satisfactory outcome. Patients with full-thickness rotator cuff tears were less likely to experience a successful result (55%). Workmen’s compensation cases had a satisfactory outcome in 74%, with a predominance of good over excellent results. Excluding those with full-thickness tears and work-related injuries, a satisfactory outcome was achieved in 90%. Arthroscopic subacromial decompression for mechanical impingement of the rotator cuff is a technically demanding procedure requiring appropriate skills as well as careful preoperative treatment and evaluation. For individuals in whom conservative measures fail and who meet stringent criteria, namely, a largely intact rotator cuff and a non-work-related injury, a highly reliable and satisfying outcome can be anticipated by both patient and surgeon. Key Words: Subacromial decompression-Rotator cuff disease.
rather than as a single static event. Although other etiologies for rotator cuff disease such as tensile failure due to overuse (3,4) and secondary rotator cuff compression with instability (5) do occur, this
Mechanical impingement of the rotator cuff is a common source of recurring pain and disability in the active population. Neer’s (1,2) classic work served to organize the clinician’s approach to rotator cuff disease, and most importantly, to define rotator cuff pathology as a spectrum of disease
review focuses on primary impingement occurring at the anterior one-third of the acromion and coracoacromial arch. Open decompression has been widely used for impingement with satisfying results (6-9). With the recent introduction of an arthroscopic technique for decompression, several authors have reported favorable results with arthroscopic subacromial decompression (ASD) (10-U). This retrospective review addresses several pertinent issues: the effi-
From the Orthopaedic Specialists of Santa Barbara, Santa Barbara, California. Address correspondence and reprint requests to Dr. R. K. N. Ryu, 536 East Arrellaga Street, Santa Barbara, CA 93103, U.S.A. The results of this study were presented at the Arthroscopy Association of North America Meeting (AANA), April 1991, San Diego, California.
141
142
R. K. A’. RYV
cacy of the arthroscopic approach based on the degree of rotator cuff pathology, the need for a uniform rotator cuff rating format to allow comparative analysis, the significance of subacromial space changes, and the impact of preoperative criteria including radiographic analysis. MATERIALS AND METHODS A retrospective review of 61 consecutive ASDs form the basis for this study. Of the 61 patients, 53 (87%) were available for follow-up examinations (47 patients) or telephone questionnaires (6 patients). The average follow-up was 23 months, ranging from 12 to 50 months. Ages ranged from 27 to 81 years, with an average of 47 years. Thirty-four men and 19 women were in the study group, with the dominant extremity involved in 37 of the 53 cases (70%). Using the classification system of Snyder et al. (13) for grading rotator cuff disease, 11 had full-thickness tears, 35 had partial tears, and 7 patients were thought to have normal-appearing or minimally irritated rotator cuffs at the time of arthroscopy. Indications for surgical intervention consisted of failure to improve significantly despite rigorous conservative management of at least 6 months’ duration, although in individuals with known rotator cuff tears, the interval to surgery was often shorter. The conservative program consisted of a trial of nonsteroidal antiinflammatory medication in conjunction with appropriate rest, formal physical therapy, and at least one subacromial steroid injection. The procedures were all performed by a single surgeon (R.K.N.R.) implementing the same operative techniques save for small modifications as equipment design improved. The results were analyzed using the UCLA rating system (Table 1) (10,ll). Twelve of the 53 patients had adjunctive procedures including two manipulations, six Mumford procedures (four open and two arthroscopic), and four calcific deposit excisions (done arthroscopically at the time of the decompression). Eighty-six percent of the patients underwent either a magnetic resonance scan or arthrogram preoperatively. As the series progressed, patients routinely had a supraspinatus outlet view obtained both pre- and postoperatively for comparison. All patients underwent formal physical therapy after the procedure, and their return to activities varied based on the degree of rotator cuff damage
Arthroscopy,
Vol. 8, No. 2, 1992
TABLE 1. UCLA shoulder rating scale Score” Pain Present always and unbearable; strong medication frequently Present always, but bearable; strong medication occasionally None or little at rest, present during light activities; salicylates frequently Present during heavy or particular activities only; salicylates occasionally Occasional and slight None Function Unable to use limb Only light activities possible Able to do light housework or most activities of daily living Most housework, shopping, and driving possible; able to do hair and to dress and undress, including fastening bra Slight restriction only; able to work above shoulder level Normal activities Active forward flexion (degrees) 2150 120-150 90-120 45-90 30.45 <30 Strength of forward flexion (manual muscle testing) Grade 5 (normal) Grade 4 (good) Grade 3 (fair) Grade 2 (poor) Grade 1 (muscle contraction) Grade 0 (nothing) Satisfaction of the patient Satisfied and better Satisfied and worse a Maximum score 35 points; 34-3.5-excellent; 21-17-fair; 0-20-poor.
1 2 4 6 8 10 1 2 4 6
8 10 5 4 : 1 0 5 4 3 2 1 0 5 0
28-33-good;
present at surgery. The majority of decompressions with a partial lesion were released to full activities within 3 months of the procedure. Rotator cuff pathology was graded using Snyder’s “ABC” system in which “A” represents the articular side of the cuff, “B” is bursal, and “C” connotes a complete tear connecting the two surfaces. Once the location was ascertained, the severity of the tear was recorded as: O-a normal cuff, I-superficial synovial or bursal irritation with no tendon fiber failure, II-minimal tearing of tendon fibers <2 cm, III-moderate disruption with fraying and a 2-3-cm area of involvement, and IV-severe fraying and delamination involving >a 4-cm area. The individual tendons were identified as su-
ARTHROSCOPIC
SUBACROMIAL
praspinatus, infraspinatus, rotator interval, and subscapularis. All procedures were videotaped, stored, and reviewed for purposes of categorizing the location and severity of the rotator cuff pathology. The 46 patients with either a partial or full-thickness rotator cuff tear were classified and the tear types are summarized in Table 2. OPERATIVE TECHNIQUE All procedures were performed on an outpatient basis. The patients were administered a general anesthetic while they were in the supine position, and then they were examined when they were under anesthesia. A manipulation was carried out at this time if needed. Individuals with underlying glenohumeral instability were further evaluated with diagnostic arthroscopy but did not undergo an ASD and, therefore, are not included in this report. This distinction was thought to be of utmost importance and this series reflects a deliberate attempt to exclude individuals with rotator cuff symptoms secondary to primary instability. The patient was then placed into a lateral decubitus position. Five to 15 lb of countertraction were used with the shoulder initially placed in 45” of abduction and 10” of flexion. A standard posterior portal was used for inspection of the glenohumeral joint once the landmarks had been mapped out. With the 25” arthroscope in the joint, probing of the cuff from
DECOMPRESSION
a lateral portal was undertaken to determine the condition of the rotator cuff and to probe for any subtle tears. The blunt trochar was also passed from the posterior portal, palpating the undersurface of the acromion in an effort to appreciate the shape of the acromion and in particular the degree of spurring anteriorly. At the conclusion of the case, this same maneuver allowed assessment of the adequacy of the decompression. The arthroscope was then redirected into the subacromial space for bursoscopy. If an articular-side rotator cuff lesion was noted, this was marked with an l&gauge needle and absorbable suture via the lateral portal such that the corresponding bursal aspect of the cuff could be inspected. If a tear was suspected but was thought to be very small, a diluted methylene blue test was performed with direct viewing on the bursal side of the cuff to evaluate for extravasation or blistering. The coracoacromial ligament was evaluated for roughening, fraying, or hypertrophy (Fig. 1). The acromioclavicular (AC) joint was likewise evaluated, often requiring some stripping of the inferior capsule to gain adequate visualization. Once the subacromial pathology was assessed, and a decompression was deemed appropriate, the procedure was initiated by a subperiosteal stripping of the coracoacromial ligament to expose the underlying bony spur. The acromial attachment of the coracoacromial ligament was then resected to prevent reattachment and this was followed by
TABLE 2. Tear types and results of operation Objective rating Excellent Snyder classification
Good
Fair
(Satisfactory)
Complete AIIISS AIVSSIIS Total
BIIISS BIVSWIS
CIII CIV
2 9 11
Partial AISS AIIISS A0 A0 A0 AISS AIISS AIISS AIIISS/IS Total
BO BO BISSIIS BIISS BIIISS BIISS BIISS BIIISS BIIISS
co co co co co co co co co
3
1 1
Poor
(Unsatisfactory) 0 4
0
1
4
0
1 3 14 3 2 2 4 3 35
Arthroscopy,
Vol. 8. No. 2. 1992
R. K. N. RYU
144
at the time of the decompression, and in four of these patients a massive rotator cuff tear with AC joint pain and degenerative spurring was present. The other two patients had significant preoperative AC joint pain with some radiographic evidence of AC joint arthritis as well as significant relief from a preoperative localized injection. Additionally, 17 of the 53 patients had some evidence of significant labral tearing whereas 5 had evidence of significant (>25%) biceps tendon fraying and 4 patients demonstrated complete biceps ruptures. Thirteen patients had evidence of chondromalacic change of the glenohumeral articulation, and the majority of these patients had complete rotator cuff tears. The labral and biceps lesions were debrided at the time of the arthroscopic decompression. RADIOGRAPHY FIG. 1. Arthroscopic view of subacromial space with frayed coracoacromial ligament (large arrow) and bursal-side partial rotator cuff tear (small arrow).
an acromioplasty accomplished with a 5.5-mm rounded burr. The extent of the resection extended from the AC joint to the anterolateral corner of the acromion and extended posteriorly -2.5-3 cm. Once a thorough resection and decompression was accomplished, the subacromial space was reinspected and the distance from the acromial surface to the bursal aspect of the rotator cuff was measured with a probe and compared with the predecompression distance. The shoulder was then taken through a range of motion to verify the adequacy of the decompression, and again a blunt trochar was used to evaluate the shape of the acromion postdecompression. All puncture wounds were left open and a dry, sterile dressing was applied after the routine use of bupivacaine (Marcaine) in the subacromial space. ASSOCIATED PATHOLOGY Two patients required a manipulation because of adhesions. Adhesions were formed because of limited motion caused by the primary impingement, and these cases were considered secondary adhesive capsulitis caused by a primary impingement syndrome. Four patients underwent calcific deposit removal at the time of the arthroscopic decompression, each one being accomplished arthroscopically. Six patients underwent a Mumford procedure Arthroscopy,
Vol. 8, No. 2, 1992
Thirty-four of the 53 patients had comparison pre- and postoperative outlet views. The preoperative morphology was analyzed according to shape and was categorized as type I, II, or III as described by Bigliani et al. (16) and Morrison and Bigliani (17) 19 were considered type III morphology whereas 15 were categorized as type I or II. Postoperatively, an outlet view was obtained to evaluate the adequacy of the acromioplasty (Figs. 2 and 3). It is noteworthy that in those patients with failed acromioplasties, the outlet view was helpful in identifying those patients whose poor outcomes were considered technical errors with inadequate bone being resected. Two of the three patients subsequently underwent an open acromioplasty. RESULTS Using the UCLA rating system, overall 81% of the patients achieved an excellent (32%) or good (49%) outcome. Nineteen percent of the study group experienced an unsatisfactory outcome (fair or poor), with 15% fair and 4% poor. The same criteria used by Ellman, Esch et al., and Snyder et al. (IO,1 1,13) were used, with scores of 34-35 considered excellent, 28-33 good, 21-27 fair, and O-20 poor. Seven patients were judged to exhibit normal or minimally irritated rotator cuffs at the time of surgery. In the seven, either coracoacromial ligament change or a thickened bursa was present, with the rotator cuff showing no evidence of tendon fiber failure. Two excellent, four good, 0 fair, and one
ARTHROSCOPIC
FIG. 2. Preoperative morphology.
outlet view demonstrates
SUBACROMIAL
type III acromial
poor outcome were noted. With such a small group, compelling numbers are lacking. However, six of the seven were judged to be significantly improved even in the absence of bursal-side rotator cuff pathology, although coraco-acromial (C-A) ligament and/or bursal changes were present. Patients with partial rotator cuff tears had a success rate of nearly 86% (30 of 35). Excellent results were achieved in 39% whereas 46% were rated good. Fifteen percent were considered unsatisfactory with only fair outcomes. No poor results were recorded. Individuals with full-thickness rotator cuff tears fared less well overall as a group. The success rate was 55% whereas 45% were deemed unsatisfactory. However, only those with a massive nonrepairable tear were not treated with an open repair; hence this subgroup was self-selected for severity. Of the 11 complete tears, the outcome was excellent in 2, good in 4, fair in 4, with 1 poor result. It is noteworthy that among the four fair outcomes in the full-thickness rotator cuff tear category, pain and function scores were significantly improved postoperatively, although range of motion and strength im-
DECOMPRESSION
proved very little. The average preoperative pain and function scores increased from 2.8 and 2.5 to 6.5 and 6.2, respectively. Six on the pain scale indicates presence of pain during heavy activities with only occasional antiinflammatory medication needed, whereas 6 on the function scale indicates an ability to do most housework, shop, drive, fasten a brassiere, comb one’s hair, and independently dress. Among workmen’s compensation cases, a satisfactory outcome of 74% was recorded, with the majority of the patients noting a good (63%) rather than excellent (11%) result. Similar less successful interventions in the workmen’s compensation category have been noted by others (11,15,18). If those patients with full-thickness rotator cuff tears as well as workmen’s compensation cases are eliminated, the overall success rate in this series was 90%, with a failure rate of 10%. Thirty-four of the 53 patients had comparison pre- and postoperative outlet views. Of the 34, 19 demonstrated type III morphology whereas 15 were considered type I or II. Those with a type III acromion had a success rate of nearly 90%, whereas as a group the type I and II acromions had a successful outcome in only 73%.
FIG. 3. Postoperative acromial resection.
outlet view confirms
Arthroscopy,
the adequacy
of
Vol. 8. No. 2, 1992
146
R. K. N. RYV COMPLICATIONS
Arthroscopic subacromial decompression proved to be a safe procedure, with only one technical complication encountered. In one elderly patient with a massive rotator cuff tear, a portion of the deltoid was injured during the coracoacromial ligament resection. A small incision was made and the rent was closed. The injury did slow the immediate postoperative program, but the overall result was not compromised. There were no infections or neurovascular injuries. DISCUSSION Chronic rotator cuff pain and disability is a common ailment in the active and older population. The mechanical stresses endured by the rotator cuff, as well as its poor vascular design, have been well described (19,20). If a mechanical lesion is present and can be confirmed with a careful preoperative evaluation, and if a trial of conservative measures has failed, then these individuals may benefit from an arthroscopic decompression. That an adequate decompression can be achieved arthroscopically has been determined in the laboratory by Gartsman et al. (21). The challenge to the treating surgeon is to correctly select those patients who would benefit from a surgical extension of treatment. Currently, in addition to a thorough history and examination, preoperative radiographs including an outlet view are obtained and are valuable in the selection process. Those patients with a type III acromial morphology characterized by a smoothly curved undersurface associated with a sharp anterior hook are judged to be the best candidates for a decompression. Although normal morphology with a hypertrophic coracoacromial ligament or shallow slope can be a cause of impingement, the bony excrescence involving the anterior acromion leading to a type III morphology is clearly the most common etiology for chronic impingement. Several patients with only mild subacromial changes but persistent symptoms underwent subacromial decompression, and the results indicate that individuals with early impingement do well. This may suggest that the tendonopathy may lag behind the pain initiated by the impingement process, and that early but prudent intervention may be desirable. Furthermore, although the subacromial changes may be subtle, bursal-side pathology Arthroscopy,
Vol. 8, No. 2, 1992
should be present if an arthroscopic subacromial decompression is to be justified. Patients with partial rotator cuff lesions, even of sizable dimensions, can anticipate a satisfactory outcome in well over 80% of the cases. Whether or not these partial tears heal once the impingement is relieved is not known. Of considerable interest was the small subgroup of partial tears involving only the articular surface of the rotator cuff. Of the four patients in this category, three were considered failures. These patients most likely represented an error in diagnosis. Rotator cuff lesions involving only the articular side should be considered tensile failure lesions, possibly secondary to occult instability, and are unlikely to benefit from a decompression. Improvement in this subgroup after subacromial decompression may derive from the rest after surgery rather than the intrinsic benefit of surgery itself. Individuals with massive rotator cuff tears can but are unlikely to achieve an excellent outcome. However, many in this category did experience pain relief, especially at night, as well as a modest improvement in function. Power and strength were largely unaffected by the procedure. The unexpected improvement, although sometimes modest, in the full-thickness tear category after subacromial decompression has been reported by others (22-24). Notably, Burkhart (25) has further defined the rotator-cuff-deficient patient into several categories based on the presence or absence of an intact force couple. This determination may serve as a prognostic indicator for the potential benefit of an arthroscopic subacromial decompression. As other authors have noted (11,15,18), a caveat is in order with regard to workmen’s compensation cases that present with intractable shoulder pain, unresponsive to conservative measures. Results in this series mandate that in work-related cases, stringent preoperative criteria should be fulfilled. A type III acromial morphology present on the preoperative radiograph as well as a positive impingement test with the patient unaware of the desired response to the subacromial injection are useful in the selection process. Those individuals who fulfill these criteria are likely to have a satisfactory outcome, although the procedure was less successful in this group. CONCLUSIONS Arthroscopic subacromial decompression is an excellent and reliable means of relieving mechanical
ARTHROSCOPIC
SUBACROMIAL
impingement of the rotator cuff in the properly selected individual. Conservative measures should be tried before considering ASD for recalcitrant impingement symptoms. Selected individuals with normal rotator cuffs but subacromial changes and those with partial rotator cuff lesions can anticipate a successful outcome more than 80% of the time. Although some success with full-thickness rotator cuff tears has been achieved, arthroscopic subacromial decompression should be selectively used as a salvage procedure in those individuals with large or massive rotator cuff tears. In the workmen’s compensation population, stringent criteria should be applied in the selection process. Type III acromial morphology and a positive impingement test are indicators that a satisfactory outcome can be achieved. ASD is a demanding but potentially successful technique for addressing rotator cuff pathology. When compared with the open procedure, the arthroscopic approach is not only effective in relieving symptoms, but permits a thorough evaluation of the rotator cuff and intraarticular structures, minimizes the risk of deltoid morbidity, contains costs, and allows a smoother, less painful rehabilitation and functional return. REFERENCES 1. Neer CS II. Impingement lesions. Clin Orfhop 1983;173: 70-7. 2. Neer CS II. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. J Bone Joint Stag [Am] 1972;54:41-50. 3. Nirschl RP. Shoulder tendinitis. E/bow and shoulder: American Academy per Extremity
of Orthopedic Surgeons Symposium on UpInjuries in Athletes. St. Louis: CV Mosby,
1986:322-37. 4. Nirschl RP. Prevention and treatment of elbow and shoulder injuries in the tennis player. C/in Sports Med 1988;7:289308.
5. Jobe FW, Kvitne RS. Shoulder pain in the overhand or throwing athlete: the relationship of anterior instability and rotator cuff impingement. Orthop Rev 1989:18:963-75.
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147
6. Hawkins RJ, Brock RM, Abrams JS, Hobeika P. Acromioplasty for impingement with an intact cuff. J Bone Joint Surg [Br] 1988;70:795-7. 7. Raggio CL, Warren RF, Sculco T. Surgical treatment of impingement syndrome: 4 year follow-up. Orthop Trans 1985; 9:48-9. 8. Post M, Cohen J. Impingement syndrome-a review of late stage II and early stage III lesions. Orthop Trans 1985;9:48. 9. Tibone JE, Jobe FW, Kerlan RK, et al. Shoulder impingement syndrome in athletes treated by an anterior acromioplasty. CBn Orthop 1985;198:134-+0. 10. Ellman H. Arthroscopic subacromial decompression: analysis of one- to three-year results. Arthroscopy 1987;3:173-81. 11. Esch JC, Ozerkis LR, Helgager JA, Kane N, Lilliott N. Arthroscopic subacromial decompression: results according to the degree of rotator cuff tear. Arthroscopy 1988;4:241-9. 12. Gartsman GM. Arthroscopic acromioplasty for lesions of the rotator cuff. J Bone Joint Stag 1990;72: 169-80. 13. Snyder SJ, Pachelli AF, Del Pizzo W, Friedman MJ, Ferkel RD, Pattee G. Partial thickness rotator cuff tears: results of arthroscopic treatment. Arthroscopy 1991;7: 1-7. 14. Altchek DW, Warren RF, Wickiewicz TL, Skyhar MJ, Ortiz G, Schwartz E. Arthroscopic acromioplasty. J Bone Joint Surg [Am] 1990;72: 1198-1207. 15. Paulos LE, Franklin JL. Arthroscopic shoulder decompression development and application. Am J Sporrs Med 1990; 18:235-44. 16. Bigliani LU, Morrison DS, April EW. The morphology of the acromion and its relationship to rotator cuff tears. Orthop Tram 1986;10:216. 17. Morrison DS, Bigliani LU. Roentgenographic analysis of acromial morphology and its relationship to rotator cuff tears. Orthop Trans 1987; 11:439. 18. Ogilvie-Harris DJ. Wiley AM, Sattarian J. Failed acromioplasty for impingement syndrome. J Bone Joint Surg [Br] 1990;72: 1070-2.
19. Rathbun JB. Macnab I. The microvascular pattern of the rotator cuff. J Bone Joint Surg [Br] 1970;52:54&53. 20. CoIield RH. Current concepts review. Rotator cuff disease of the shoulder. J Bone Joint Surg [Am] 1985;67:974-9. 21. Gartsman GM, Blair ME Jr, Noble PC, Bennett JB, Tullos HS. Arthroscopic subacromial decompression. An anatomical study. Am J Sports Med 1988;16:48-50. 22. Rockwood CA Jr. Shoulder function following decompression and irreparable cuff lesions. Orthop Trans 1984;8:92. 23. Rockwood CA Jr, Burkhead WZ. Management of patients with massive rotator cuff defects by acromioplasty and rotator cuff debridement. Orthop Trans 1988;12: 190-l. 24. Levy HJ, Gardner RD, Lemak LJ. Arthroscopic subacromial decompression in the treatment of full-thickness rotator cuff tears. Arthroscopy 1991;7:8-13. 25. Burkhart SS. Arthroscopic treatment of massive rotator cuff tears. Presented at the Eighth Annual Meeting Arthroscopic Surgery of the Shoulder, San Diego, July 1991.
Arthroscopy, Vol. 8, No. 2. 1992
The Journal of Arthroscopic
and Related Surgery
Published by Raven Press, Ltd. 0 1992 Arthroscopy
Arthroscopic
8(2):141-147
Association of North America
Subacromial Decompression: . Clinical Review
A
Richard K. N. Ryu, M.D.
Summary: Arthroscopic subacromial decompression has become a popular technique supplanting the open Neer acromioplasty in many instances of chronic rotator cuff disease. A review of 61 consecutive decompressions with a minimum follow-up of 12 months was undertaken to evaluate preoperative criteria and surgical outcomes. Of the 61 patients, 53 patients with an average follow-up of 23 months were available for review. Thirty-four men and 19 women with an average age of 47 years comprised the study group. Eleven (21%) had full-thickness tears, 35 (66%) had partial-thickness injuries, and 7 (13%) had normal-appearing rotator cuffs at the time of arthroscopy. The UCLA shoulder rating system was used to evaluate outcome. Eighty-one percent of the patients had an excellent (32%) or good (49%) result whereas 19% (15% fair and 4% poor) were considered unsatisfactory. Those with early impingement findings and partial rotator cuff tears were likely to experience a satisfactory outcome. Patients with full-thickness rotator cuff tears were less likely to experience a successful result (55%). Workmen’s compensation cases had a satisfactory outcome in 74%, with a predominance of good over excellent results. Excluding those with full-thickness tears and work-related injuries, a satisfactory outcome was achieved in 90%. Arthroscopic subacromial decompression for mechanical impingement of the rotator cuff is a technically demanding procedure requiring appropriate skills as well as careful preoperative treatment and evaluation. For individuals in whom conservative measures fail and who meet stringent criteria, namely, a largely intact rotator cuff and a non-work-related injury, a highly reliable and satisfying outcome can be anticipated by both patient and surgeon. Key Words: Subacromial decompression-Rotator cuff disease.
rather than as a single static event. Although other etiologies for rotator cuff disease such as tensile failure due to overuse (3,4) and secondary rotator cuff compression with instability (5) do occur, this
Mechanical impingement of the rotator cuff is a common source of recurring pain and disability in the active population. Neer’s (1,2) classic work served to organize the clinician’s approach to rotator cuff disease, and most importantly, to define rotator cuff pathology as a spectrum of disease
review focuses on primary impingement occurring at the anterior one-third of the acromion and coracoacromial arch. Open decompression has been widely used for impingement with satisfying results (6-9). With the recent introduction of an arthroscopic technique for decompression, several authors have reported favorable results with arthroscopic subacromial decompression (ASD) (10-U). This retrospective review addresses several pertinent issues: the effi-
From the Orthopaedic Specialists of Santa Barbara, Santa Barbara, California. Address correspondence and reprint requests to Dr. R. K. N. Ryu, 536 East Arrellaga Street, Santa Barbara, CA 93103, U.S.A. The results of this study were presented at the Arthroscopy Association of North America Meeting (AANA), April 1991, San Diego, California.
141
142
R. K. A’. RYV
cacy of the arthroscopic approach based on the degree of rotator cuff pathology, the need for a uniform rotator cuff rating format to allow comparative analysis, the significance of subacromial space changes, and the impact of preoperative criteria including radiographic analysis. MATERIALS AND METHODS A retrospective review of 61 consecutive ASDs form the basis for this study. Of the 61 patients, 53 (87%) were available for follow-up examinations (47 patients) or telephone questionnaires (6 patients). The average follow-up was 23 months, ranging from 12 to 50 months. Ages ranged from 27 to 81 years, with an average of 47 years. Thirty-four men and 19 women were in the study group, with the dominant extremity involved in 37 of the 53 cases (70%). Using the classification system of Snyder et al. (13) for grading rotator cuff disease, 11 had full-thickness tears, 35 had partial tears, and 7 patients were thought to have normal-appearing or minimally irritated rotator cuffs at the time of arthroscopy. Indications for surgical intervention consisted of failure to improve significantly despite rigorous conservative management of at least 6 months’ duration, although in individuals with known rotator cuff tears, the interval to surgery was often shorter. The conservative program consisted of a trial of nonsteroidal antiinflammatory medication in conjunction with appropriate rest, formal physical therapy, and at least one subacromial steroid injection. The procedures were all performed by a single surgeon (R.K.N.R.) implementing the same operative techniques save for small modifications as equipment design improved. The results were analyzed using the UCLA rating system (Table 1) (10,ll). Twelve of the 53 patients had adjunctive procedures including two manipulations, six Mumford procedures (four open and two arthroscopic), and four calcific deposit excisions (done arthroscopically at the time of the decompression). Eighty-six percent of the patients underwent either a magnetic resonance scan or arthrogram preoperatively. As the series progressed, patients routinely had a supraspinatus outlet view obtained both pre- and postoperatively for comparison. All patients underwent formal physical therapy after the procedure, and their return to activities varied based on the degree of rotator cuff damage
Arthroscopy,
Vol. 8, No. 2, 1992
TABLE 1. UCLA shoulder rating scale Score” Pain Present always and unbearable; strong medication frequently Present always, but bearable; strong medication occasionally None or little at rest, present during light activities; salicylates frequently Present during heavy or particular activities only; salicylates occasionally Occasional and slight None Function Unable to use limb Only light activities possible Able to do light housework or most activities of daily living Most housework, shopping, and driving possible; able to do hair and to dress and undress, including fastening bra Slight restriction only; able to work above shoulder level Normal activities Active forward flexion (degrees) 2150 120-150 90-120 45-90 30.45 <30 Strength of forward flexion (manual muscle testing) Grade 5 (normal) Grade 4 (good) Grade 3 (fair) Grade 2 (poor) Grade 1 (muscle contraction) Grade 0 (nothing) Satisfaction of the patient Satisfied and better Satisfied and worse a Maximum score 35 points; 34-3.5-excellent; 21-17-fair; 0-20-poor.
1 2 4 6 8 10 1 2 4 6
8 10 5 4 : 1 0 5 4 3 2 1 0 5 0
28-33-good;
present at surgery. The majority of decompressions with a partial lesion were released to full activities within 3 months of the procedure. Rotator cuff pathology was graded using Snyder’s “ABC” system in which “A” represents the articular side of the cuff, “B” is bursal, and “C” connotes a complete tear connecting the two surfaces. Once the location was ascertained, the severity of the tear was recorded as: O-a normal cuff, I-superficial synovial or bursal irritation with no tendon fiber failure, II-minimal tearing of tendon fibers <2 cm, III-moderate disruption with fraying and a 2-3-cm area of involvement, and IV-severe fraying and delamination involving >a 4-cm area. The individual tendons were identified as su-
ARTHROSCOPIC
SUBACROMIAL
praspinatus, infraspinatus, rotator interval, and subscapularis. All procedures were videotaped, stored, and reviewed for purposes of categorizing the location and severity of the rotator cuff pathology. The 46 patients with either a partial or full-thickness rotator cuff tear were classified and the tear types are summarized in Table 2. OPERATIVE TECHNIQUE All procedures were performed on an outpatient basis. The patients were administered a general anesthetic while they were in the supine position, and then they were examined when they were under anesthesia. A manipulation was carried out at this time if needed. Individuals with underlying glenohumeral instability were further evaluated with diagnostic arthroscopy but did not undergo an ASD and, therefore, are not included in this report. This distinction was thought to be of utmost importance and this series reflects a deliberate attempt to exclude individuals with rotator cuff symptoms secondary to primary instability. The patient was then placed into a lateral decubitus position. Five to 15 lb of countertraction were used with the shoulder initially placed in 45” of abduction and 10” of flexion. A standard posterior portal was used for inspection of the glenohumeral joint once the landmarks had been mapped out. With the 25” arthroscope in the joint, probing of the cuff from
DECOMPRESSION
a lateral portal was undertaken to determine the condition of the rotator cuff and to probe for any subtle tears. The blunt trochar was also passed from the posterior portal, palpating the undersurface of the acromion in an effort to appreciate the shape of the acromion and in particular the degree of spurring anteriorly. At the conclusion of the case, this same maneuver allowed assessment of the adequacy of the decompression. The arthroscope was then redirected into the subacromial space for bursoscopy. If an articular-side rotator cuff lesion was noted, this was marked with an l&gauge needle and absorbable suture via the lateral portal such that the corresponding bursal aspect of the cuff could be inspected. If a tear was suspected but was thought to be very small, a diluted methylene blue test was performed with direct viewing on the bursal side of the cuff to evaluate for extravasation or blistering. The coracoacromial ligament was evaluated for roughening, fraying, or hypertrophy (Fig. 1). The acromioclavicular (AC) joint was likewise evaluated, often requiring some stripping of the inferior capsule to gain adequate visualization. Once the subacromial pathology was assessed, and a decompression was deemed appropriate, the procedure was initiated by a subperiosteal stripping of the coracoacromial ligament to expose the underlying bony spur. The acromial attachment of the coracoacromial ligament was then resected to prevent reattachment and this was followed by
TABLE 2. Tear types and results of operation Objective rating Excellent Snyder classification
Good
Fair
(Satisfactory)
Complete AIIISS AIVSSIIS Total
BIIISS BIVSWIS
CIII CIV
2 9 11
Partial AISS AIIISS A0 A0 A0 AISS AIISS AIISS AIIISS/IS Total
BO BO BISSIIS BIISS BIIISS BIISS BIISS BIIISS BIIISS
co co co co co co co co co
3
1 1
Poor
(Unsatisfactory) 0 4
0
1
4
0
1 3 14 3 2 2 4 3 35
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at the time of the decompression, and in four of these patients a massive rotator cuff tear with AC joint pain and degenerative spurring was present. The other two patients had significant preoperative AC joint pain with some radiographic evidence of AC joint arthritis as well as significant relief from a preoperative localized injection. Additionally, 17 of the 53 patients had some evidence of significant labral tearing whereas 5 had evidence of significant (>25%) biceps tendon fraying and 4 patients demonstrated complete biceps ruptures. Thirteen patients had evidence of chondromalacic change of the glenohumeral articulation, and the majority of these patients had complete rotator cuff tears. The labral and biceps lesions were debrided at the time of the arthroscopic decompression. RADIOGRAPHY FIG. 1. Arthroscopic view of subacromial space with frayed coracoacromial ligament (large arrow) and bursal-side partial rotator cuff tear (small arrow).
an acromioplasty accomplished with a 5.5-mm rounded burr. The extent of the resection extended from the AC joint to the anterolateral corner of the acromion and extended posteriorly -2.5-3 cm. Once a thorough resection and decompression was accomplished, the subacromial space was reinspected and the distance from the acromial surface to the bursal aspect of the rotator cuff was measured with a probe and compared with the predecompression distance. The shoulder was then taken through a range of motion to verify the adequacy of the decompression, and again a blunt trochar was used to evaluate the shape of the acromion postdecompression. All puncture wounds were left open and a dry, sterile dressing was applied after the routine use of bupivacaine (Marcaine) in the subacromial space. ASSOCIATED PATHOLOGY Two patients required a manipulation because of adhesions. Adhesions were formed because of limited motion caused by the primary impingement, and these cases were considered secondary adhesive capsulitis caused by a primary impingement syndrome. Four patients underwent calcific deposit removal at the time of the arthroscopic decompression, each one being accomplished arthroscopically. Six patients underwent a Mumford procedure Arthroscopy,
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Thirty-four of the 53 patients had comparison pre- and postoperative outlet views. The preoperative morphology was analyzed according to shape and was categorized as type I, II, or III as described by Bigliani et al. (16) and Morrison and Bigliani (17) 19 were considered type III morphology whereas 15 were categorized as type I or II. Postoperatively, an outlet view was obtained to evaluate the adequacy of the acromioplasty (Figs. 2 and 3). It is noteworthy that in those patients with failed acromioplasties, the outlet view was helpful in identifying those patients whose poor outcomes were considered technical errors with inadequate bone being resected. Two of the three patients subsequently underwent an open acromioplasty. RESULTS Using the UCLA rating system, overall 81% of the patients achieved an excellent (32%) or good (49%) outcome. Nineteen percent of the study group experienced an unsatisfactory outcome (fair or poor), with 15% fair and 4% poor. The same criteria used by Ellman, Esch et al., and Snyder et al. (IO,1 1,13) were used, with scores of 34-35 considered excellent, 28-33 good, 21-27 fair, and O-20 poor. Seven patients were judged to exhibit normal or minimally irritated rotator cuffs at the time of surgery. In the seven, either coracoacromial ligament change or a thickened bursa was present, with the rotator cuff showing no evidence of tendon fiber failure. Two excellent, four good, 0 fair, and one
ARTHROSCOPIC
FIG. 2. Preoperative morphology.
outlet view demonstrates
SUBACROMIAL
type III acromial
poor outcome were noted. With such a small group, compelling numbers are lacking. However, six of the seven were judged to be significantly improved even in the absence of bursal-side rotator cuff pathology, although coraco-acromial (C-A) ligament and/or bursal changes were present. Patients with partial rotator cuff tears had a success rate of nearly 86% (30 of 35). Excellent results were achieved in 39% whereas 46% were rated good. Fifteen percent were considered unsatisfactory with only fair outcomes. No poor results were recorded. Individuals with full-thickness rotator cuff tears fared less well overall as a group. The success rate was 55% whereas 45% were deemed unsatisfactory. However, only those with a massive nonrepairable tear were not treated with an open repair; hence this subgroup was self-selected for severity. Of the 11 complete tears, the outcome was excellent in 2, good in 4, fair in 4, with 1 poor result. It is noteworthy that among the four fair outcomes in the full-thickness rotator cuff tear category, pain and function scores were significantly improved postoperatively, although range of motion and strength im-
DECOMPRESSION
proved very little. The average preoperative pain and function scores increased from 2.8 and 2.5 to 6.5 and 6.2, respectively. Six on the pain scale indicates presence of pain during heavy activities with only occasional antiinflammatory medication needed, whereas 6 on the function scale indicates an ability to do most housework, shop, drive, fasten a brassiere, comb one’s hair, and independently dress. Among workmen’s compensation cases, a satisfactory outcome of 74% was recorded, with the majority of the patients noting a good (63%) rather than excellent (11%) result. Similar less successful interventions in the workmen’s compensation category have been noted by others (11,15,18). If those patients with full-thickness rotator cuff tears as well as workmen’s compensation cases are eliminated, the overall success rate in this series was 90%, with a failure rate of 10%. Thirty-four of the 53 patients had comparison pre- and postoperative outlet views. Of the 34, 19 demonstrated type III morphology whereas 15 were considered type I or II. Those with a type III acromion had a success rate of nearly 90%, whereas as a group the type I and II acromions had a successful outcome in only 73%.
FIG. 3. Postoperative acromial resection.
outlet view confirms
Arthroscopy,
the adequacy
of
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R. K. N. RYV COMPLICATIONS
Arthroscopic subacromial decompression proved to be a safe procedure, with only one technical complication encountered. In one elderly patient with a massive rotator cuff tear, a portion of the deltoid was injured during the coracoacromial ligament resection. A small incision was made and the rent was closed. The injury did slow the immediate postoperative program, but the overall result was not compromised. There were no infections or neurovascular injuries. DISCUSSION Chronic rotator cuff pain and disability is a common ailment in the active and older population. The mechanical stresses endured by the rotator cuff, as well as its poor vascular design, have been well described (19,20). If a mechanical lesion is present and can be confirmed with a careful preoperative evaluation, and if a trial of conservative measures has failed, then these individuals may benefit from an arthroscopic decompression. That an adequate decompression can be achieved arthroscopically has been determined in the laboratory by Gartsman et al. (21). The challenge to the treating surgeon is to correctly select those patients who would benefit from a surgical extension of treatment. Currently, in addition to a thorough history and examination, preoperative radiographs including an outlet view are obtained and are valuable in the selection process. Those patients with a type III acromial morphology characterized by a smoothly curved undersurface associated with a sharp anterior hook are judged to be the best candidates for a decompression. Although normal morphology with a hypertrophic coracoacromial ligament or shallow slope can be a cause of impingement, the bony excrescence involving the anterior acromion leading to a type III morphology is clearly the most common etiology for chronic impingement. Several patients with only mild subacromial changes but persistent symptoms underwent subacromial decompression, and the results indicate that individuals with early impingement do well. This may suggest that the tendonopathy may lag behind the pain initiated by the impingement process, and that early but prudent intervention may be desirable. Furthermore, although the subacromial changes may be subtle, bursal-side pathology Arthroscopy,
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should be present if an arthroscopic subacromial decompression is to be justified. Patients with partial rotator cuff lesions, even of sizable dimensions, can anticipate a satisfactory outcome in well over 80% of the cases. Whether or not these partial tears heal once the impingement is relieved is not known. Of considerable interest was the small subgroup of partial tears involving only the articular surface of the rotator cuff. Of the four patients in this category, three were considered failures. These patients most likely represented an error in diagnosis. Rotator cuff lesions involving only the articular side should be considered tensile failure lesions, possibly secondary to occult instability, and are unlikely to benefit from a decompression. Improvement in this subgroup after subacromial decompression may derive from the rest after surgery rather than the intrinsic benefit of surgery itself. Individuals with massive rotator cuff tears can but are unlikely to achieve an excellent outcome. However, many in this category did experience pain relief, especially at night, as well as a modest improvement in function. Power and strength were largely unaffected by the procedure. The unexpected improvement, although sometimes modest, in the full-thickness tear category after subacromial decompression has been reported by others (22-24). Notably, Burkhart (25) has further defined the rotator-cuff-deficient patient into several categories based on the presence or absence of an intact force couple. This determination may serve as a prognostic indicator for the potential benefit of an arthroscopic subacromial decompression. As other authors have noted (11,15,18), a caveat is in order with regard to workmen’s compensation cases that present with intractable shoulder pain, unresponsive to conservative measures. Results in this series mandate that in work-related cases, stringent preoperative criteria should be fulfilled. A type III acromial morphology present on the preoperative radiograph as well as a positive impingement test with the patient unaware of the desired response to the subacromial injection are useful in the selection process. Those individuals who fulfill these criteria are likely to have a satisfactory outcome, although the procedure was less successful in this group. CONCLUSIONS Arthroscopic subacromial decompression is an excellent and reliable means of relieving mechanical
ARTHROSCOPIC
SUBACROMIAL
impingement of the rotator cuff in the properly selected individual. Conservative measures should be tried before considering ASD for recalcitrant impingement symptoms. Selected individuals with normal rotator cuffs but subacromial changes and those with partial rotator cuff lesions can anticipate a successful outcome more than 80% of the time. Although some success with full-thickness rotator cuff tears has been achieved, arthroscopic subacromial decompression should be selectively used as a salvage procedure in those individuals with large or massive rotator cuff tears. In the workmen’s compensation population, stringent criteria should be applied in the selection process. Type III acromial morphology and a positive impingement test are indicators that a satisfactory outcome can be achieved. ASD is a demanding but potentially successful technique for addressing rotator cuff pathology. When compared with the open procedure, the arthroscopic approach is not only effective in relieving symptoms, but permits a thorough evaluation of the rotator cuff and intraarticular structures, minimizes the risk of deltoid morbidity, contains costs, and allows a smoother, less painful rehabilitation and functional return. REFERENCES 1. Neer CS II. Impingement lesions. Clin Orfhop 1983;173: 70-7. 2. Neer CS II. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. J Bone Joint Stag [Am] 1972;54:41-50. 3. Nirschl RP. Shoulder tendinitis. E/bow and shoulder: American Academy per Extremity
of Orthopedic Surgeons Symposium on UpInjuries in Athletes. St. Louis: CV Mosby,
1986:322-37. 4. Nirschl RP. Prevention and treatment of elbow and shoulder injuries in the tennis player. C/in Sports Med 1988;7:289308.
5. Jobe FW, Kvitne RS. Shoulder pain in the overhand or throwing athlete: the relationship of anterior instability and rotator cuff impingement. Orthop Rev 1989:18:963-75.
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6. Hawkins RJ, Brock RM, Abrams JS, Hobeika P. Acromioplasty for impingement with an intact cuff. J Bone Joint Surg [Br] 1988;70:795-7. 7. Raggio CL, Warren RF, Sculco T. Surgical treatment of impingement syndrome: 4 year follow-up. Orthop Trans 1985; 9:48-9. 8. Post M, Cohen J. Impingement syndrome-a review of late stage II and early stage III lesions. Orthop Trans 1985;9:48. 9. Tibone JE, Jobe FW, Kerlan RK, et al. Shoulder impingement syndrome in athletes treated by an anterior acromioplasty. CBn Orthop 1985;198:134-+0. 10. Ellman H. Arthroscopic subacromial decompression: analysis of one- to three-year results. Arthroscopy 1987;3:173-81. 11. Esch JC, Ozerkis LR, Helgager JA, Kane N, Lilliott N. Arthroscopic subacromial decompression: results according to the degree of rotator cuff tear. Arthroscopy 1988;4:241-9. 12. Gartsman GM. Arthroscopic acromioplasty for lesions of the rotator cuff. J Bone Joint Stag 1990;72: 169-80. 13. Snyder SJ, Pachelli AF, Del Pizzo W, Friedman MJ, Ferkel RD, Pattee G. Partial thickness rotator cuff tears: results of arthroscopic treatment. Arthroscopy 1991;7: 1-7. 14. Altchek DW, Warren RF, Wickiewicz TL, Skyhar MJ, Ortiz G, Schwartz E. Arthroscopic acromioplasty. J Bone Joint Surg [Am] 1990;72: 1198-1207. 15. Paulos LE, Franklin JL. Arthroscopic shoulder decompression development and application. Am J Sporrs Med 1990; 18:235-44. 16. Bigliani LU, Morrison DS, April EW. The morphology of the acromion and its relationship to rotator cuff tears. Orthop Tram 1986;10:216. 17. Morrison DS, Bigliani LU. Roentgenographic analysis of acromial morphology and its relationship to rotator cuff tears. Orthop Trans 1987; 11:439. 18. Ogilvie-Harris DJ. Wiley AM, Sattarian J. Failed acromioplasty for impingement syndrome. J Bone Joint Surg [Br] 1990;72: 1070-2.
19. Rathbun JB. Macnab I. The microvascular pattern of the rotator cuff. J Bone Joint Surg [Br] 1970;52:54&53. 20. CoIield RH. Current concepts review. Rotator cuff disease of the shoulder. J Bone Joint Surg [Am] 1985;67:974-9. 21. Gartsman GM, Blair ME Jr, Noble PC, Bennett JB, Tullos HS. Arthroscopic subacromial decompression. An anatomical study. Am J Sports Med 1988;16:48-50. 22. Rockwood CA Jr. Shoulder function following decompression and irreparable cuff lesions. Orthop Trans 1984;8:92. 23. Rockwood CA Jr, Burkhead WZ. Management of patients with massive rotator cuff defects by acromioplasty and rotator cuff debridement. Orthop Trans 1988;12: 190-l. 24. Levy HJ, Gardner RD, Lemak LJ. Arthroscopic subacromial decompression in the treatment of full-thickness rotator cuff tears. Arthroscopy 1991;7:8-13. 25. Burkhart SS. Arthroscopic treatment of massive rotator cuff tears. Presented at the Eighth Annual Meeting Arthroscopic Surgery of the Shoulder, San Diego, July 1991.
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