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Midterm results of arthroscopic co-planing of the acromioclavicular joint
Midterm results of arthroscopic co-planing of the acromioclavicular joint Don Buford, Jr, MD, Timothy Mologne, MD, Steven McGrath, MD, Greg Heinen, MD, and Stephen Snyder, MD, Van Nuys, Calif
Background: There has been recent concern about longterm morbidity associated with arthroscopic co-planing of the acromioclavicular joint in the treatment of impingement syndrome. Objective: The purpose of this study was to assess the results of the co-planing procedure, special attention being paid to acromioclavicular joint morbidity. Methods: The study included 56 patients who were operated on by the senior author. Outcomes were evaluated both objectively and subjectively through physical examinations and telephone surveying. Each patient had subacromial decompression at the time of the index surgery. Other concomitant arthroscopic procedures included rotator cuff repair and labral debridement or repair. Results: Average follow-up was 4 years (range, 2-7 years). Thirty-five (95%) of 37 patients had no subjective pain and no objective tenderness to direct palpation or compression of the acromioclavicular joint. The joint was not clinically hypermobile in comparison with that on the opposite side in any patient. In all, 95% of patients had good or excellent results in terms of the University of California at Los Angeles Shoulder Score. Of the 2 patients who did have pain and tenderness at the acromioclavicular joint, both had had multiple operations on their shoulders before the index procedure. Nineteen patients were not examined clinically but did complete a telephone survey; these 19 patients were not symptomatic at the acromioclavicular joint. Conclusions: To fully treat impingement syndrome, the surgeon should remove osteophytes under the lateral clavicle and medial acromion. With good technique, the surgeon can leave the anterior, posterior, and superior acromioclavicular joint capsule intact. We conclude that for appropriate clinical indications, beveling the inferior 20% to 25% of the clavicle to make it co-planar with the decompressed acromion is safe and is not an etiologic factor in acromioFrom the Southern California Orthopedic Institute, Van Nuys, Calif. Reprint requests: Don Buford, Jr, MD, 411 N. Washington St, Suite 1000, Dallas, TX 75246. Copyright © 2000 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2000/$12.00 + 0 32/1/109560 doi:10.1067/mse.2000.109560
498
clavicular joint pain or instability. (J Shoulder Elbow Surg 2000;9:498-501.)
One
of the frequently mentioned advantages of arthroscopic shoulder surgery is that the surgeon can address the patient’s pathosis with minimal invasiveness and morbidity. With the rapid development of arthroscopic shoulder surgery equipment and techniques, many procedures are now possible that were not feasible 10 years ago. Whether the surgery performed is open or arthroscopic, the indications and goals should be the same. The most commonly accepted indication for subacromial decompression is primary mechanical impingement with or without rotator cuff injury.1,2,6,10,12 The goal in the surgical treatment of impingement syndrome is to remove any offending osteophyte that narrows the supraspinatus outlet. Usually this requires removing the anterior hook of the acromion and flattening the undersurface for approximately 2.5 cm from front to back. Many surgeons have recognized that, as popularized by Neer,10 spurs under the acromioclavicular (AC) joint can also cause mechanical impingement on the rotator cuff. Subacromial decompression is incomplete unless spurs at the undersurface of the medial acromion or lateral clavicle are removed.10 In his shoulder textbook, Neer10 states that excision of AC joint spurs is “an important part of anterior acromioplasty whenever such prominences are present.” Others have supported Neer’s view that any inferiorly directed spurs under the AC joint should be flattened.2 Neer performed his subacromial decompressions open and co-planed the AC joint when the pathosis demanded it. With regard to AC joint pain observed with the open beveling of the undersurface of the AC joint, Neer mentioned that in his patients “this has not been seen as a complication.”10 With the advent of arthroscopic surgery, surgeons began to apply the same treatment principles in a less invasive fashion, ostensibly to further decrease morbidity, which is associated with open procedures, while achieving the same results. Subacromial decompression is now accepted as having clinical results similar to those of open subacromial decompression.2,5,7,12 Recently, there has been increased interest in arthroscopic co-planing of the AC joint because of concerns that the joint may be destabilized, leading to pain or
Buford et al
J Shoulder Elbow Surg Volume 9, Number 6
Figure 1 Distal clavicle before co-planing.
instability. Some surgeons have noted increased AC joint pain in 40% of their patients as soon as 8 months after surgery, a significant number of these patients requiring reoperation.3 Other surgeons have reported that their patients have developed clinically unstable AC joints 5 to 7 years after arthroscopic co-planing.9 Some surgeons now advocate not violating the AC joint capsule at all unless a Mumford procedure is being performed.3 Presumably, this would mean not decompressing the medial acromial facet, because if the medial acromial facet is decompressed, then the AC joint capsule must be violated. There could be many reasons that arthroscopic treatment of pathosis has increased morbidity in comparison with open surgery. Given the recent proliferation in conflicting opinions, we decided to review our midterm results to determine whether our patients were having postoperative pain or instability at the AC joint.
MATERIALS AND METHODS Patient sample From January 1992 to December 1997, a random selection of patients who had arthroscopic subacromial decompression and co-planing of the AC joint was identified from the senior author’s (D.B.) surgical log. During this period, the number of patients who had subacromial decompressions was 868; of these, 735 (84.7%) had coplaning of the AC joint at the same time. During the same period, the number of patients who underwent Mumford procedures was 122. The only exclusion criterion was a time since surgery of less than 2 years. From the initial list of 150 patients, 56 were contacted; all of these patients agreed to participate. The remaining 94 patients could not be located. Physical examination or telephone survey was used in every case. Nineteen of the 56 patients lived too far from our office to return for physical examination; we have pro-
499
Figure 2 Distal clavicle after co-planing.
vided their survey results for interest only and did not include these results in our statistics. The senior author had specific preoperative clinical and radiologic indications for arthroscopic subacromial decompression and co-planing of the AC joint. All patients treated surgically for impingement syndrome had failed nonoperative measures, including nonsteroidal anti-inflammatory drugs, subacromial injections, and shoulder rest. If any patient had significant AC joint symptoms and clinical findings, he or she was a candidate not for co-planing but rather for a Mumford procedure. Similarly, if a patient had significant AC joint degenerative disease, a Mumford procedure was the procedure of choice. Only patients with inferior AC spurs noted on radiograph and no significant AC tenderness with direct palpation or arm adduction were considered for co-planing of the AC joint.
Surgical Technique The lateral decubitus position was used in all cases, and the same standard posterior, lateral, and anterior arthroscopic portals were used in all cases. Surgical technique included removal of the inferior AC joint capsule to allow debridement of the inferior acromial and clavicular spurs for complete decompression of the supraspinatus outlet. Great care was taken to leave the anterior, superior, and posterior AC joint capsule intact. A successful debridement resulted in removal of the inferior 20% to 25% of the clavicle so that the clavicle was co-planar with the decompressed medial acromial facet (Figures 1 and 2). All patients had subacromial decompression in association with AC joint co-planing. In addition to decompression and co-planing, procedures done at the time of surgery included rotator cuff repair or debridement (32), biceps tenodesis (9), and labral debridement (5).
Study design A focused physical examination was done to assess AC joint pain and tenderness provoked with horizontal arm adduction and direct joint palpation. The clavicle was also
500
Buford et al
assessed clinically for hypermobility in comparison with the opposite shoulder. Because we were primarily interested in whether patients were having AC pain or instability, we limited our examination to these areas of investigation. Each included patient underwent a University of California at Los Angeles (UCLA) Shoulder Score evaluation.
RESULTS The study sample size was 56 patients. The average patient age was 61 years (range, 43-83 years). The average follow-up was 4 years (range, 2-7 years). Of the 56 shoulders, 40 were on the dominant side. Thirty-seven patients were available for in-office physical examination, and 19 were evaluated by telephone survey. Two of the 37 patients examined had AC joint tenderness to palpation and with horizontal adduction; these 2 symptomatic patients did not have any clinical evidence of hypermobility of the clavicle in comparison with the opposite shoulder. The remaining 35 patients examined were all asymptomatic and had no significant clavicle instability. All 19 of the patients evaluated by telephone survey were asymptomatic, according to their reports. In all, 35 (95%) of 37 patients examined were clinically asymptomatic at the AC joint. The 95% CI (exact binomial distribution test) reveals that from 87.2% to 99.1% of our patients were asymptomatic at an average of 4 years after surgery. UCLA Shoulder Score results paralleled the clinical findings. The average score was 33 out of a possible 35 points. Good and excellent results were obtained in 95% (35/37) of the patients in the study; the remaining 5% (2/37) were graded as fair. DISCUSSION In this study, 56 patients, randomly selected on the basis of availability, underwent clinical and survey evaluation 2 to 7 years after arthroscopic subacromial decompression and co-planing of the AC joint. We were unable to contact a significant number of our identified sample group of 150 patients for several reasons. In some cases, the patient no longer had an active phone number and no forwarding information was available. Some patients had moved out of the Southern California area. A number of patients had traveled to Van Nuys from considerable distances for their operations and were unable to return for clinical examination. These patients were included in our telephone survey. No patient who lived in the immediate Southern California area declined to take part in the study. In all, of 150 patients identified as meeting our criterion—ie, a minimum of 2 years since surgery—only 56 were available for inclusion in the study. If a substantial number of the patients whom we were unable to contact had AC joint instability or pain, then our results could be skewed. Our telephone survey results for the 19 patients who could not
J Shoulder Elbow Surg November/December 2000
return for examination show that these patients were doing well, at least according to their own assessment. This investigation, the goal of which was to present clinical results of co-planing the AC joint in conjunction with subacromial decompression, does have some shortcomings. For one thing, it was retrospective in nature. For another thing, we did not obtain postoperative radiographs at the time of the study evaluation; therefore we could not quantify any changes in clavicle position radiographically. However, we were primarily interested in discovering whether our patients were having pain or limitations in function after surgery, and we feel that our study design adequately addressed this question. There is a wide variation in the clinical results reported for co-planing of the AC joint to remove impinging spurs.3,9 Some authors report the development of clinically significant AC pain within an average of 8 months after surgery, with reoperation in more than 30% of patients. In the study with the longest clinical follow-up and the largest study sample, no significant complications were found in more than 1200 patients at an average of 6.7 years after arthroscopic resection of the inferior AC joint capsule during acromioplasty.13 A recent study of 5 cadavers has suggested that AC joint co-planing destabilizes the AC joint and may be an etiologic factor in instability and pain.11 Our attempt to make sense of the wide variation in opinions expressed by competent arthroscopic surgeons has led to the conclusion that differences in preoperative indications, surgical technique, and associated pathoses may all play some role. Our preoperative indications are specific and comprehensive. Patients typically have failed nonsurgical treatment for impingement syndrome. Typical nonoperative measures include nonsteroidal anti-inflammatory drug therapy, subacromial injections with steroid, and rehabilitative measures to increase shoulder range of motion. Patients must have inferior spurring under the AC joint identified on plain radiographs. In addition, there should be no signs of AC degenerative joint disease with cystic changes in the clavicle or acromion or generalized joint spurring. Frequently, radiographic findings of subtle cystic changes in the clavicle or acromion can be appreciated only with the use of a hot lamp and may be missed otherwise. We are also careful to examine the patient for pain at the AC joint with palpation or horizontal adduction or shoulder extension. Finally, if any preoperative studies, such as MRI or bone scanning, reveal more diffuse involvement of the distal clavicle, then merely co-planing the AC joint may result in clinical failure. In our opinion, if the patient has any signs of more generalized AC arthritic changes or pain and tenderness at the joint, a Mumford procedure is indicated to completely treat the AC joint pathosis. Surgical technique is significant, as recent anatomical studies of the AC joint capsule function and attachments suggest. We are careful to leave the superior
Buford et al
J Shoulder Elbow Surg Volume 9, Number 6
and posterior joint capsule intact; in anatomical sectioning studies, these two portions of the capsule have been shown to be the most significant in preventing posterior clavicle displacement.4,8 The inferior clavicle spur can be successfully removed by burring the inferior 20% to 25% of the distal clavicle to make it co-planar with the decompressed medial acromial facet. Any resection of the medial acromial facet violates the inferior AC joint capsule, which can continue under the medial acromion for as much as 1.5 cm.4 There is no need to carry the infraclavicular decompression more medially than 5 mm or to remove the superior 75% of the clavicle that forms the articulation with the acromion. Patients may have other shoulder pathoses that make co-planing less likely to succeed. In our study, each of the 2 patients with continued AC joint pain had been operated on at least once by another surgeon before the index arthroscopic procedure. Although we did not study this small group further, their continued pain may suggest that a Mumford procedure should be the procedure of choice in patients undergoing second and third shoulder operations. Surgeons wishing to treat outlet impingement fully must address spurring under the AC joint. Removing the inferior AC joint capsule to decompress the medial acromial facet and lateral clavicle has not resulted in any significant morbidity in our patients with an average of 4 years’ follow-up. We have not found any signs of AC joint pain or instability in our patients after AC joint co-planing. Furthermore, no patients have required reoperation for AC joint symptoms. We continue to await longer-term follow-up to help with our surgical decision-making. On the basis of our study, we conclude that co-planing the AC joint with removal of the inferior joint cap-
501
sule is safe and is not an etiologic factor in significant AC pain or instability. REFERENCES 1. Daluga DJ, Dobozi W. The influence of distal clavicle resection and rotator cuff repair of the effectiveness of anterior acromioplasty. Clin Orthop 1989;247:117-23. 2. Ellman H. Arthroscopic subacromial decompression: analysis of one to three year results. Arthroscopy 1987;3:173-81. 3. Fischer BW, Gross RM, McCarthy JA, Arroyo JS. Incidence of acromioclavicular joint complications following arthroscopic subacromial decompression. Arthroscopy 1999;15:241-8. 4. Fukuda K, Craig EV, An K, Cofield RH, Chao EYS. Biomechanical study of the ligamentous system of the acromioclavicular joint. J Bone Joint Surg Am 1986;68A:434-40. 5. Gartsman GM, Combs AH, Davis PF, Tullos HS. Arthroscopic acromioclavicular joint resection. Am J Sports Med 1991;19:2-5. 6. Gartsman GM: Arthroscopic resection of the acromioclavicular joint. Am J Sports Med 1993;21:71-7. 7. Henry MH, Liu SL, Loffredo AJ. Arthroscopic management of the acromioclavicular joint disorder. Clin Orthop 1995;316:276-83. 8. Klimkiewicz JJ, Williams GR, Sher JS, Karduna A, Ianotti JP. The acromioclavicular capsule as a restraint to posterior translation of the clavicle: a biomechanical analysis. J Shoulder Elbow Surg 1999;8:119-24. 9. Kuster MS, Hales PF, Davis SJ. The effects of arthroscopic acromioplasty on the acromioclavicular joint. J Shoulder Elbow Surg 1998;7:140-3. 10. Neer C. Shoulder reconstruction. Philadelphia: WB Saunders; 1990. 11. Roberts RM, Tasto JP. The effects of acromioclavicular joint stability after arthroscopic co-planing. Arthroscopy 1998;14(Suppl 1):S12. 12. Sachs RA, Stone ML, Devine S. Open vs arthroscopic acromioplasty: a prospective randomized study. Arthroscopy 1994;10: 248-54. 13. Weber SC. Co-planing the AC joint at the time of acromioplasty: a long-term study. Proceedings of the 1999 meeting of the American Association of Nurse Anesthetists. Arthroscopy Association of North America, Vancouver, BC, Canada, April15-18, 1999.
Background: There has been recent concern about longterm morbidity associated with arthroscopic co-planing of the acromioclavicular joint in the treatment of impingement syndrome. Objective: The purpose of this study was to assess the results of the co-planing procedure, special attention being paid to acromioclavicular joint morbidity. Methods: The study included 56 patients who were operated on by the senior author. Outcomes were evaluated both objectively and subjectively through physical examinations and telephone surveying. Each patient had subacromial decompression at the time of the index surgery. Other concomitant arthroscopic procedures included rotator cuff repair and labral debridement or repair. Results: Average follow-up was 4 years (range, 2-7 years). Thirty-five (95%) of 37 patients had no subjective pain and no objective tenderness to direct palpation or compression of the acromioclavicular joint. The joint was not clinically hypermobile in comparison with that on the opposite side in any patient. In all, 95% of patients had good or excellent results in terms of the University of California at Los Angeles Shoulder Score. Of the 2 patients who did have pain and tenderness at the acromioclavicular joint, both had had multiple operations on their shoulders before the index procedure. Nineteen patients were not examined clinically but did complete a telephone survey; these 19 patients were not symptomatic at the acromioclavicular joint. Conclusions: To fully treat impingement syndrome, the surgeon should remove osteophytes under the lateral clavicle and medial acromion. With good technique, the surgeon can leave the anterior, posterior, and superior acromioclavicular joint capsule intact. We conclude that for appropriate clinical indications, beveling the inferior 20% to 25% of the clavicle to make it co-planar with the decompressed acromion is safe and is not an etiologic factor in acromioFrom the Southern California Orthopedic Institute, Van Nuys, Calif. Reprint requests: Don Buford, Jr, MD, 411 N. Washington St, Suite 1000, Dallas, TX 75246. Copyright © 2000 by Journal of Shoulder and Elbow Surgery Board of Trustees. 1058-2746/2000/$12.00 + 0 32/1/109560 doi:10.1067/mse.2000.109560
498
clavicular joint pain or instability. (J Shoulder Elbow Surg 2000;9:498-501.)
One
of the frequently mentioned advantages of arthroscopic shoulder surgery is that the surgeon can address the patient’s pathosis with minimal invasiveness and morbidity. With the rapid development of arthroscopic shoulder surgery equipment and techniques, many procedures are now possible that were not feasible 10 years ago. Whether the surgery performed is open or arthroscopic, the indications and goals should be the same. The most commonly accepted indication for subacromial decompression is primary mechanical impingement with or without rotator cuff injury.1,2,6,10,12 The goal in the surgical treatment of impingement syndrome is to remove any offending osteophyte that narrows the supraspinatus outlet. Usually this requires removing the anterior hook of the acromion and flattening the undersurface for approximately 2.5 cm from front to back. Many surgeons have recognized that, as popularized by Neer,10 spurs under the acromioclavicular (AC) joint can also cause mechanical impingement on the rotator cuff. Subacromial decompression is incomplete unless spurs at the undersurface of the medial acromion or lateral clavicle are removed.10 In his shoulder textbook, Neer10 states that excision of AC joint spurs is “an important part of anterior acromioplasty whenever such prominences are present.” Others have supported Neer’s view that any inferiorly directed spurs under the AC joint should be flattened.2 Neer performed his subacromial decompressions open and co-planed the AC joint when the pathosis demanded it. With regard to AC joint pain observed with the open beveling of the undersurface of the AC joint, Neer mentioned that in his patients “this has not been seen as a complication.”10 With the advent of arthroscopic surgery, surgeons began to apply the same treatment principles in a less invasive fashion, ostensibly to further decrease morbidity, which is associated with open procedures, while achieving the same results. Subacromial decompression is now accepted as having clinical results similar to those of open subacromial decompression.2,5,7,12 Recently, there has been increased interest in arthroscopic co-planing of the AC joint because of concerns that the joint may be destabilized, leading to pain or
Buford et al
J Shoulder Elbow Surg Volume 9, Number 6
Figure 1 Distal clavicle before co-planing.
instability. Some surgeons have noted increased AC joint pain in 40% of their patients as soon as 8 months after surgery, a significant number of these patients requiring reoperation.3 Other surgeons have reported that their patients have developed clinically unstable AC joints 5 to 7 years after arthroscopic co-planing.9 Some surgeons now advocate not violating the AC joint capsule at all unless a Mumford procedure is being performed.3 Presumably, this would mean not decompressing the medial acromial facet, because if the medial acromial facet is decompressed, then the AC joint capsule must be violated. There could be many reasons that arthroscopic treatment of pathosis has increased morbidity in comparison with open surgery. Given the recent proliferation in conflicting opinions, we decided to review our midterm results to determine whether our patients were having postoperative pain or instability at the AC joint.
MATERIALS AND METHODS Patient sample From January 1992 to December 1997, a random selection of patients who had arthroscopic subacromial decompression and co-planing of the AC joint was identified from the senior author’s (D.B.) surgical log. During this period, the number of patients who had subacromial decompressions was 868; of these, 735 (84.7%) had coplaning of the AC joint at the same time. During the same period, the number of patients who underwent Mumford procedures was 122. The only exclusion criterion was a time since surgery of less than 2 years. From the initial list of 150 patients, 56 were contacted; all of these patients agreed to participate. The remaining 94 patients could not be located. Physical examination or telephone survey was used in every case. Nineteen of the 56 patients lived too far from our office to return for physical examination; we have pro-
499
Figure 2 Distal clavicle after co-planing.
vided their survey results for interest only and did not include these results in our statistics. The senior author had specific preoperative clinical and radiologic indications for arthroscopic subacromial decompression and co-planing of the AC joint. All patients treated surgically for impingement syndrome had failed nonoperative measures, including nonsteroidal anti-inflammatory drugs, subacromial injections, and shoulder rest. If any patient had significant AC joint symptoms and clinical findings, he or she was a candidate not for co-planing but rather for a Mumford procedure. Similarly, if a patient had significant AC joint degenerative disease, a Mumford procedure was the procedure of choice. Only patients with inferior AC spurs noted on radiograph and no significant AC tenderness with direct palpation or arm adduction were considered for co-planing of the AC joint.
Surgical Technique The lateral decubitus position was used in all cases, and the same standard posterior, lateral, and anterior arthroscopic portals were used in all cases. Surgical technique included removal of the inferior AC joint capsule to allow debridement of the inferior acromial and clavicular spurs for complete decompression of the supraspinatus outlet. Great care was taken to leave the anterior, superior, and posterior AC joint capsule intact. A successful debridement resulted in removal of the inferior 20% to 25% of the clavicle so that the clavicle was co-planar with the decompressed medial acromial facet (Figures 1 and 2). All patients had subacromial decompression in association with AC joint co-planing. In addition to decompression and co-planing, procedures done at the time of surgery included rotator cuff repair or debridement (32), biceps tenodesis (9), and labral debridement (5).
Study design A focused physical examination was done to assess AC joint pain and tenderness provoked with horizontal arm adduction and direct joint palpation. The clavicle was also
500
Buford et al
assessed clinically for hypermobility in comparison with the opposite shoulder. Because we were primarily interested in whether patients were having AC pain or instability, we limited our examination to these areas of investigation. Each included patient underwent a University of California at Los Angeles (UCLA) Shoulder Score evaluation.
RESULTS The study sample size was 56 patients. The average patient age was 61 years (range, 43-83 years). The average follow-up was 4 years (range, 2-7 years). Of the 56 shoulders, 40 were on the dominant side. Thirty-seven patients were available for in-office physical examination, and 19 were evaluated by telephone survey. Two of the 37 patients examined had AC joint tenderness to palpation and with horizontal adduction; these 2 symptomatic patients did not have any clinical evidence of hypermobility of the clavicle in comparison with the opposite shoulder. The remaining 35 patients examined were all asymptomatic and had no significant clavicle instability. All 19 of the patients evaluated by telephone survey were asymptomatic, according to their reports. In all, 35 (95%) of 37 patients examined were clinically asymptomatic at the AC joint. The 95% CI (exact binomial distribution test) reveals that from 87.2% to 99.1% of our patients were asymptomatic at an average of 4 years after surgery. UCLA Shoulder Score results paralleled the clinical findings. The average score was 33 out of a possible 35 points. Good and excellent results were obtained in 95% (35/37) of the patients in the study; the remaining 5% (2/37) were graded as fair. DISCUSSION In this study, 56 patients, randomly selected on the basis of availability, underwent clinical and survey evaluation 2 to 7 years after arthroscopic subacromial decompression and co-planing of the AC joint. We were unable to contact a significant number of our identified sample group of 150 patients for several reasons. In some cases, the patient no longer had an active phone number and no forwarding information was available. Some patients had moved out of the Southern California area. A number of patients had traveled to Van Nuys from considerable distances for their operations and were unable to return for clinical examination. These patients were included in our telephone survey. No patient who lived in the immediate Southern California area declined to take part in the study. In all, of 150 patients identified as meeting our criterion—ie, a minimum of 2 years since surgery—only 56 were available for inclusion in the study. If a substantial number of the patients whom we were unable to contact had AC joint instability or pain, then our results could be skewed. Our telephone survey results for the 19 patients who could not
J Shoulder Elbow Surg November/December 2000
return for examination show that these patients were doing well, at least according to their own assessment. This investigation, the goal of which was to present clinical results of co-planing the AC joint in conjunction with subacromial decompression, does have some shortcomings. For one thing, it was retrospective in nature. For another thing, we did not obtain postoperative radiographs at the time of the study evaluation; therefore we could not quantify any changes in clavicle position radiographically. However, we were primarily interested in discovering whether our patients were having pain or limitations in function after surgery, and we feel that our study design adequately addressed this question. There is a wide variation in the clinical results reported for co-planing of the AC joint to remove impinging spurs.3,9 Some authors report the development of clinically significant AC pain within an average of 8 months after surgery, with reoperation in more than 30% of patients. In the study with the longest clinical follow-up and the largest study sample, no significant complications were found in more than 1200 patients at an average of 6.7 years after arthroscopic resection of the inferior AC joint capsule during acromioplasty.13 A recent study of 5 cadavers has suggested that AC joint co-planing destabilizes the AC joint and may be an etiologic factor in instability and pain.11 Our attempt to make sense of the wide variation in opinions expressed by competent arthroscopic surgeons has led to the conclusion that differences in preoperative indications, surgical technique, and associated pathoses may all play some role. Our preoperative indications are specific and comprehensive. Patients typically have failed nonsurgical treatment for impingement syndrome. Typical nonoperative measures include nonsteroidal anti-inflammatory drug therapy, subacromial injections with steroid, and rehabilitative measures to increase shoulder range of motion. Patients must have inferior spurring under the AC joint identified on plain radiographs. In addition, there should be no signs of AC degenerative joint disease with cystic changes in the clavicle or acromion or generalized joint spurring. Frequently, radiographic findings of subtle cystic changes in the clavicle or acromion can be appreciated only with the use of a hot lamp and may be missed otherwise. We are also careful to examine the patient for pain at the AC joint with palpation or horizontal adduction or shoulder extension. Finally, if any preoperative studies, such as MRI or bone scanning, reveal more diffuse involvement of the distal clavicle, then merely co-planing the AC joint may result in clinical failure. In our opinion, if the patient has any signs of more generalized AC arthritic changes or pain and tenderness at the joint, a Mumford procedure is indicated to completely treat the AC joint pathosis. Surgical technique is significant, as recent anatomical studies of the AC joint capsule function and attachments suggest. We are careful to leave the superior
Buford et al
J Shoulder Elbow Surg Volume 9, Number 6
and posterior joint capsule intact; in anatomical sectioning studies, these two portions of the capsule have been shown to be the most significant in preventing posterior clavicle displacement.4,8 The inferior clavicle spur can be successfully removed by burring the inferior 20% to 25% of the distal clavicle to make it co-planar with the decompressed medial acromial facet. Any resection of the medial acromial facet violates the inferior AC joint capsule, which can continue under the medial acromion for as much as 1.5 cm.4 There is no need to carry the infraclavicular decompression more medially than 5 mm or to remove the superior 75% of the clavicle that forms the articulation with the acromion. Patients may have other shoulder pathoses that make co-planing less likely to succeed. In our study, each of the 2 patients with continued AC joint pain had been operated on at least once by another surgeon before the index arthroscopic procedure. Although we did not study this small group further, their continued pain may suggest that a Mumford procedure should be the procedure of choice in patients undergoing second and third shoulder operations. Surgeons wishing to treat outlet impingement fully must address spurring under the AC joint. Removing the inferior AC joint capsule to decompress the medial acromial facet and lateral clavicle has not resulted in any significant morbidity in our patients with an average of 4 years’ follow-up. We have not found any signs of AC joint pain or instability in our patients after AC joint co-planing. Furthermore, no patients have required reoperation for AC joint symptoms. We continue to await longer-term follow-up to help with our surgical decision-making. On the basis of our study, we conclude that co-planing the AC joint with removal of the inferior joint cap-
501
sule is safe and is not an etiologic factor in significant AC pain or instability. REFERENCES 1. Daluga DJ, Dobozi W. The influence of distal clavicle resection and rotator cuff repair of the effectiveness of anterior acromioplasty. Clin Orthop 1989;247:117-23. 2. Ellman H. Arthroscopic subacromial decompression: analysis of one to three year results. Arthroscopy 1987;3:173-81. 3. Fischer BW, Gross RM, McCarthy JA, Arroyo JS. Incidence of acromioclavicular joint complications following arthroscopic subacromial decompression. Arthroscopy 1999;15:241-8. 4. Fukuda K, Craig EV, An K, Cofield RH, Chao EYS. Biomechanical study of the ligamentous system of the acromioclavicular joint. J Bone Joint Surg Am 1986;68A:434-40. 5. Gartsman GM, Combs AH, Davis PF, Tullos HS. Arthroscopic acromioclavicular joint resection. Am J Sports Med 1991;19:2-5. 6. Gartsman GM: Arthroscopic resection of the acromioclavicular joint. Am J Sports Med 1993;21:71-7. 7. Henry MH, Liu SL, Loffredo AJ. Arthroscopic management of the acromioclavicular joint disorder. Clin Orthop 1995;316:276-83. 8. Klimkiewicz JJ, Williams GR, Sher JS, Karduna A, Ianotti JP. The acromioclavicular capsule as a restraint to posterior translation of the clavicle: a biomechanical analysis. J Shoulder Elbow Surg 1999;8:119-24. 9. Kuster MS, Hales PF, Davis SJ. The effects of arthroscopic acromioplasty on the acromioclavicular joint. J Shoulder Elbow Surg 1998;7:140-3. 10. Neer C. Shoulder reconstruction. Philadelphia: WB Saunders; 1990. 11. Roberts RM, Tasto JP. The effects of acromioclavicular joint stability after arthroscopic co-planing. Arthroscopy 1998;14(Suppl 1):S12. 12. Sachs RA, Stone ML, Devine S. Open vs arthroscopic acromioplasty: a prospective randomized study. Arthroscopy 1994;10: 248-54. 13. Weber SC. Co-planing the AC joint at the time of acromioplasty: a long-term study. Proceedings of the 1999 meeting of the American Association of Nurse Anesthetists. Arthroscopy Association of North America, Vancouver, BC, Canada, April15-18, 1999.