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Acromion-splitting approach through an os acromiale for repair of a massive rotator cuff tear
Case Report
Acromion-Splitting Approach Through an Os Acromiale for Repair of a Massive Rotator Cuff Tear Neil Richman,
M.D., Alan Curtis, M.D., and Michael Hayman,
M.D.
Summary: Os acromiale, failure of fusion of the secondary centers of ossification of the acromion process, has been noted as a contributing factor in shoulder impingement syndrome and rotator cuff tears. Treatments for symptomatic os acromiale with or without rotator cuff tears have been reported in the literature and range from excision of small fragments to fusion of larger fragments with internal fixation and bone grafting. Generally, rotator cuff repairs have been performed when possible. We report an acromion splitting approach through an existing os acromiale to gain exposure for the repair of a massive rotator cuff tear. Subsequent to this repair, the acromion was repaired with internal fixation. Good functional use of the patient's upper extremity was obtained and the patient expressed satisfaction with the surgical outcome. The acromion splitting approach is a viable approach in patients with an os acromiale and a coexistent rotator cuff tear. Key Words: Os acromiale--Rotator cuff repair.
ailure of fusion of the secondary centers of ossification of the acromion process of the scapula results in a condition termed os acromiale. 1 0 s acromiale has been noted to be a contributing factor to shoulder impingement syndrome and rotator cuff tears. 21° The following case presentation describes an acromion splitting approach through an existing os acromiale with subsequent fixation to facilitate the repair of a massive rotator cuff tear.
F
CASE PRESENTATION The patient is a 46-year-old man with a history of polio since the age of 6 years, with resultant quadriplegia leaving him wheelchair bound and with use of his
From the Sports Medicine Service, New England Baptist Hospital Bone and Joint Institute, Boston, Massachusetts, U.S.A. Address correspondence and reprint requests to Alan Curtis, M.D., c/o Pro Sports Orthopedics, 830 Boylston St, Suite 1134, Brookline, MA 02167, U.S.A. © 1997 by the Arthroscopy Association of North America 0749-8063/97/1305-162653.00/0
652
left upper extremity only. The patient had fallen from his wheelchair sustaining an injury to his left shoulder and was referred to our service for evaluation 5 weeks after his injury. Examination of the patient's left shoulder revealed forward flexion to only 100 ° with discomfort. External and internal rotation was significantly limited. Deltoid strength with forward flexion was graded at 3/5. A magnetic resonance imaging (MRI) scan was obtained which revealed a massive left rotator cuff tear (Fig 1). Incidental findings of plain radiographs and the MRI included the presence of an os acromiale, meso-acromion type (Figs 2 and 3). Because of the added disability of a massive rotator cuff tear to the patient's overly dominant extremity, rotator cuff repair was recommended. The patient presented for elective left shoulder arthroscopy with subacromial decompression and rotator cuff repair. Arthroscopic findings confirmed the massive rotator cuff tear extending from the superior edge of the subscapularis tendon to and including the teres minor tendon with significant retraction to the level of the glenoid rim (Fig 4). Additionally, there
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 13, No 5 (October), 1997: pp 652-655
ROTATOR CUFF REPAIR THROUGH OS ACROMIALE
653
FIG 3. Preoperative MRI axial view of left shoulder showing os acromiale. FIG 1. Preoperative MRI coronal view of left shoulder showing massive rotator cuff tear.
was a partial tear of the biceps tendon. Arthroscopic findings in the subacromial space revealed a significantly mobile os acromiale fragment that comprised nearly one half of the anterior aspect of the acromion (Fig 5). The coracoacromial ligament was debrided arthroscopically but not detached from the anterior aspect o f the acromion. This was done so as not to disturb the anterior deltoid attachment to the os acromiale fragment. The arthroscope was removed and a standard minilateral deltoid splitting approach was then performed by extending the lateral arthroscopic portal superiorly
FIG 2. Preoperative axillary view radiograph of left shoulder showing os acromiale,
to the level of the acromion. Full-thickness skin flaps were developed. The lateral deltoid muscle was then split in the direction of its fibers from the lateral portal superiorly to the lateral acromion edge for a total length of approximately 4 cm. A suture was placed at the inferior aspect of the split to prevent further propagation to protect the inferiorly located axillary nerve. The incision was extended medially over the acromion and the junction between the os fragment and the remaining acromion was identified and opened leaving the medial aspect intact. This allowed for retraction of the os fragment anteriorly and superiorly, hinged on its medial attachment, providing excellent exposure of the rotator
FIG 4. Arthroscopic view of glenohumeral joint. HH, humeral head; GL, glenoid fossa; RC, rotator cuff.
654
N. RICHMAN ET AL.
4/5 strength and good functional use of the left upper extremity. The patient had no pain at rest and only mild discomfort with moderate activities, including transfers from his wheelchair. Compared with a preoperative UCLA shoulder rating of 10, the patient's postoperative rating improved to 23, with a score of greater than 21 representing a satisfactory result.n The patient expressed satisfaction with his outcome thus far. DISCUSSION
FIG 5. Arthroscopic view of left shoulder subacromial space from posterior portal showing os acromiale (above), retracted edge of rotator cuff and exposed humeral head (below).
cuff. The cuff was mobilized using retention sutures and the cuff edge was carefully freshened several millimeters in width to healthy, bleeding tissue. The cuff was then repaired to a bony trough along the greater tuberosity just off the articular surface with weave sutures through bone tunnels and supplemented by suture anchors. (Mitek Surgical Products, Inc, Westwood, MA). The os acromiale fragment was repaired by removing the fibrocartilage from opposing edges and then fixing the fragment to the remaining acromion with a partially threaded 4-0 cannulated screw placed from posterior to anterior. Fixation was augmented by several nonabsorbable sutures placed through drill holes on both sides of the repair. An intraoperative radiograph confirmed adequate screw placement across the os acromiale. The patient was placed in an arm immobilizer with a cyrotherapy cuff applied. He was hospitalized over night for observation, pain control, and prophylactic intravenous antibiotic therapy. The patient's postoperative regimen consisted of 4 weeks of well-arm-assisted passive range of motion exercises of the operated shoulder in addition to a home continuous passive motion device used with forward elevation from 0 ° to 100 °. At 4 weeks, well-arm-assisted active range of motion exercises were begun. The patient progressed steadily with his postoperative rehabilitation in regard to strength and range of motion. His comfort level also improved. Radiographic evaluation of the acromion at 10 weeks showed stable fixation of the fragment with early healing (Fig 6). At 6 months after surgery, the patient had greater than 120 ° of forward flexion of the left shoulder with
The incidence of os acromiale in the general population has been estimated at 1% to 15%. 12 Its presence is usually detected as an incidental finding on an axillary radiograph of the shoulder. 6 Although the incidence of shoulder symptoms directly related to the presence of an os acromiale is unknown, previous authors have noted the association between os acromiale rotator cuff impingement as well as rotator cuff tears, zl° Successful treatment for os acromiale with associated shoulder symptoms remains allusive. General treatment guidelines have been proposed by Bigliani et al., 4 recommending excising small acromial fragments and fusion of larger ones with internal fixation and bone grafting. Associated rotator cuff repairs are performed when possible. 2,s Concerns regarding anterior deltoid detachment with fragment excision and persistent subacromial impingement and hardware problems with fragment fusion continue to complicate treatment results. 24'6 Edelson et al. 6 noted that excision of the os acromiale in a
FIG 6. Postoperativeaxillary view radiograph of left shoulder showing healing across os acromiale, with interfragmentaryscrew.
ROTATOR CUFF REPAIR THROUGH OS ACROMIALE
patient with a massive irreparable rotator cuff tear significantly compromised anterior deltoid and overall shoulder function. The authors concluded that fusion of the fragment under this circumstance was recommended over fragment excision. Armengol et al., 2 in follow-up of the work of Bigliani et al., 4 noted that the most satisfactory results in their series of 42 cases were obtained when a modified acromioplasty was performed, which retained the superficial cortical shell of the os acromiale and its deltoid attachments, in contrast to fragment excision or fusion. With regard to repair of massive rotator cuff tears, Paulos et all I presented a series of 32 patients with either very large or massive rotator cuff tears and significant retraction that were addressed through an acromion splitting approach. Initially described by Kessel and Watson, 13 the approach used by Paulos et al. entailed a lateral deltoid splitting mini-lateral approach with medial extension through the acromion. The exposure afforded by this approach allows for excellent visualization of the cuff with aggressive mobilization while maintaining the integrity of the anterior deltoid insertion to the acromion. Acromion repair was by way of nonabsorbable sutures through drill holes. At an average follow-up of 33.4 months for 38 shoulders, 27 were rated good to excellent, and 11 were rated fair to poor by the UCLA shoulder rating scale. In the case presently described, several of the preceding principles were incorporated in the treatment of our patient. Because of his partial quadriplegia, the patient relied solely on his left upper extremity for carrying out activities of daily living. A massive rotator cuff tear significantly compromised his left shoulder function. Thus, obtaining a satisfactory cuff repair was of great importance. Presence of the very mobile os acromiale further added to the complexity of the case. Considering the findings of Edelson et al., 6 fragment excision was not as favorable an option as fixation/ fusion. Exposure of the rotator cuff utilized the acromion splitting approach as described by Paulos et all I and incorporated the presence of the os acromiale as delineating the region of the osteotomy. Anterior deltoid insertion was maintained and the cuff tear was well exposed to facilitate mobilization and repair. After
655
standard rotator cuff repair techniques, repair of the os fragment combined the suture technique used by Paulos et al.l~ along with interfragmentary screw fixation as used by Edelson et al. 6 Bone grafting was not performed. Preliminary results of the case reveal satisfactory cuff function with early healing across the os acromiale. The patient's symptoms remain well abated. In summary, incorporating previously described principles for treatment of symptomatic os acromiale and surgical exposure for repair of massive rotator cuff tears, an acromion splitting approach through an existing os acromiale with subsequent fragment fixation was used to surgically treat a massive rotator cuff tear with a coexistent os acromiale. This appears to be a viable surgical alternative to treating this complexity of problems based on the preliminary results of this case.
REFERENCES 1. Samilson RL. Congenital and developmental anomalies of the shoulder girdle. Orthop Clin North Am 1980; 11:219-231. 2. Armengol J, Brittis D, Pollock RG, Flatow EL, Self EB, Bigliani LU. The association of an unfused acromial epiphysis with tears of the rotator cuff: A review of 42 cases. Orthop Trans 1994; 17:975-976. 3. Beim GM, Warner JP. Symptomatic os acromiale recognition and treatment. Pittsburgh Orthop J 1996;7:46-51. 4. Bigliani LU, Norris TR, Fischer J, Neer CS. The relationship between the unfused acromial epiphysis and subacromial impingement lesions. Orthop Trans 1983; 7:138. 5. Burkhart SS. Os acromiale in a professional tennis player. Am J Sports Med 1992;20:483-484. 6. Edelson JG, Zuckerman J, Hershkovitz I. Os acromiale: anatomy and surgical implications. J Bone Joint Surg Br 1993;74:551-
555. 7. Hutchinson MR, Beenstra MA. Arthroscopic decompression of shoulder impingement secondary to os acromiale. Arthroscopy 1993;9:28-32. 8. Mudge MK, Wood VE, Frykman GK. Rotator cuff tears associated with os acromiale. J Bone Joint Surg Am 1984;66:427429. 9. Park JG, Lee JK, Phelps CT. Os acromiale associated with rotator cuff impingement: MR imaging of the shoulder. Radiology 1994; 193:255-257. 10. Sterling JC, Meyers MC, Chesshir W, Calvo RD. Os acromiale in a baseball catcher. Med Sci Sports Exerc 1995;27:795-799. 11. Paulos LE, Meislin RJ, Drawbert J. The acromion-splitting approach for large and massive rotator cuff tears. Am J Sports" Med 1994;22:306-312. 12. Liberson F. Os acromiale: A contested anomaly. J Bone Joint Surg 1937; 19:683-689. 13. Kessel L, Watson M. The painful arc syndrome. Clinical classification as a guide to management. J Bone Joint Surg Br 1977; 59:166-172.
Acromion-Splitting Approach Through an Os Acromiale for Repair of a Massive Rotator Cuff Tear Neil Richman,
M.D., Alan Curtis, M.D., and Michael Hayman,
M.D.
Summary: Os acromiale, failure of fusion of the secondary centers of ossification of the acromion process, has been noted as a contributing factor in shoulder impingement syndrome and rotator cuff tears. Treatments for symptomatic os acromiale with or without rotator cuff tears have been reported in the literature and range from excision of small fragments to fusion of larger fragments with internal fixation and bone grafting. Generally, rotator cuff repairs have been performed when possible. We report an acromion splitting approach through an existing os acromiale to gain exposure for the repair of a massive rotator cuff tear. Subsequent to this repair, the acromion was repaired with internal fixation. Good functional use of the patient's upper extremity was obtained and the patient expressed satisfaction with the surgical outcome. The acromion splitting approach is a viable approach in patients with an os acromiale and a coexistent rotator cuff tear. Key Words: Os acromiale--Rotator cuff repair.
ailure of fusion of the secondary centers of ossification of the acromion process of the scapula results in a condition termed os acromiale. 1 0 s acromiale has been noted to be a contributing factor to shoulder impingement syndrome and rotator cuff tears. 21° The following case presentation describes an acromion splitting approach through an existing os acromiale with subsequent fixation to facilitate the repair of a massive rotator cuff tear.
F
CASE PRESENTATION The patient is a 46-year-old man with a history of polio since the age of 6 years, with resultant quadriplegia leaving him wheelchair bound and with use of his
From the Sports Medicine Service, New England Baptist Hospital Bone and Joint Institute, Boston, Massachusetts, U.S.A. Address correspondence and reprint requests to Alan Curtis, M.D., c/o Pro Sports Orthopedics, 830 Boylston St, Suite 1134, Brookline, MA 02167, U.S.A. © 1997 by the Arthroscopy Association of North America 0749-8063/97/1305-162653.00/0
652
left upper extremity only. The patient had fallen from his wheelchair sustaining an injury to his left shoulder and was referred to our service for evaluation 5 weeks after his injury. Examination of the patient's left shoulder revealed forward flexion to only 100 ° with discomfort. External and internal rotation was significantly limited. Deltoid strength with forward flexion was graded at 3/5. A magnetic resonance imaging (MRI) scan was obtained which revealed a massive left rotator cuff tear (Fig 1). Incidental findings of plain radiographs and the MRI included the presence of an os acromiale, meso-acromion type (Figs 2 and 3). Because of the added disability of a massive rotator cuff tear to the patient's overly dominant extremity, rotator cuff repair was recommended. The patient presented for elective left shoulder arthroscopy with subacromial decompression and rotator cuff repair. Arthroscopic findings confirmed the massive rotator cuff tear extending from the superior edge of the subscapularis tendon to and including the teres minor tendon with significant retraction to the level of the glenoid rim (Fig 4). Additionally, there
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 13, No 5 (October), 1997: pp 652-655
ROTATOR CUFF REPAIR THROUGH OS ACROMIALE
653
FIG 3. Preoperative MRI axial view of left shoulder showing os acromiale. FIG 1. Preoperative MRI coronal view of left shoulder showing massive rotator cuff tear.
was a partial tear of the biceps tendon. Arthroscopic findings in the subacromial space revealed a significantly mobile os acromiale fragment that comprised nearly one half of the anterior aspect of the acromion (Fig 5). The coracoacromial ligament was debrided arthroscopically but not detached from the anterior aspect o f the acromion. This was done so as not to disturb the anterior deltoid attachment to the os acromiale fragment. The arthroscope was removed and a standard minilateral deltoid splitting approach was then performed by extending the lateral arthroscopic portal superiorly
FIG 2. Preoperative axillary view radiograph of left shoulder showing os acromiale,
to the level of the acromion. Full-thickness skin flaps were developed. The lateral deltoid muscle was then split in the direction of its fibers from the lateral portal superiorly to the lateral acromion edge for a total length of approximately 4 cm. A suture was placed at the inferior aspect of the split to prevent further propagation to protect the inferiorly located axillary nerve. The incision was extended medially over the acromion and the junction between the os fragment and the remaining acromion was identified and opened leaving the medial aspect intact. This allowed for retraction of the os fragment anteriorly and superiorly, hinged on its medial attachment, providing excellent exposure of the rotator
FIG 4. Arthroscopic view of glenohumeral joint. HH, humeral head; GL, glenoid fossa; RC, rotator cuff.
654
N. RICHMAN ET AL.
4/5 strength and good functional use of the left upper extremity. The patient had no pain at rest and only mild discomfort with moderate activities, including transfers from his wheelchair. Compared with a preoperative UCLA shoulder rating of 10, the patient's postoperative rating improved to 23, with a score of greater than 21 representing a satisfactory result.n The patient expressed satisfaction with his outcome thus far. DISCUSSION
FIG 5. Arthroscopic view of left shoulder subacromial space from posterior portal showing os acromiale (above), retracted edge of rotator cuff and exposed humeral head (below).
cuff. The cuff was mobilized using retention sutures and the cuff edge was carefully freshened several millimeters in width to healthy, bleeding tissue. The cuff was then repaired to a bony trough along the greater tuberosity just off the articular surface with weave sutures through bone tunnels and supplemented by suture anchors. (Mitek Surgical Products, Inc, Westwood, MA). The os acromiale fragment was repaired by removing the fibrocartilage from opposing edges and then fixing the fragment to the remaining acromion with a partially threaded 4-0 cannulated screw placed from posterior to anterior. Fixation was augmented by several nonabsorbable sutures placed through drill holes on both sides of the repair. An intraoperative radiograph confirmed adequate screw placement across the os acromiale. The patient was placed in an arm immobilizer with a cyrotherapy cuff applied. He was hospitalized over night for observation, pain control, and prophylactic intravenous antibiotic therapy. The patient's postoperative regimen consisted of 4 weeks of well-arm-assisted passive range of motion exercises of the operated shoulder in addition to a home continuous passive motion device used with forward elevation from 0 ° to 100 °. At 4 weeks, well-arm-assisted active range of motion exercises were begun. The patient progressed steadily with his postoperative rehabilitation in regard to strength and range of motion. His comfort level also improved. Radiographic evaluation of the acromion at 10 weeks showed stable fixation of the fragment with early healing (Fig 6). At 6 months after surgery, the patient had greater than 120 ° of forward flexion of the left shoulder with
The incidence of os acromiale in the general population has been estimated at 1% to 15%. 12 Its presence is usually detected as an incidental finding on an axillary radiograph of the shoulder. 6 Although the incidence of shoulder symptoms directly related to the presence of an os acromiale is unknown, previous authors have noted the association between os acromiale rotator cuff impingement as well as rotator cuff tears, zl° Successful treatment for os acromiale with associated shoulder symptoms remains allusive. General treatment guidelines have been proposed by Bigliani et al., 4 recommending excising small acromial fragments and fusion of larger ones with internal fixation and bone grafting. Associated rotator cuff repairs are performed when possible. 2,s Concerns regarding anterior deltoid detachment with fragment excision and persistent subacromial impingement and hardware problems with fragment fusion continue to complicate treatment results. 24'6 Edelson et al. 6 noted that excision of the os acromiale in a
FIG 6. Postoperativeaxillary view radiograph of left shoulder showing healing across os acromiale, with interfragmentaryscrew.
ROTATOR CUFF REPAIR THROUGH OS ACROMIALE
patient with a massive irreparable rotator cuff tear significantly compromised anterior deltoid and overall shoulder function. The authors concluded that fusion of the fragment under this circumstance was recommended over fragment excision. Armengol et al., 2 in follow-up of the work of Bigliani et al., 4 noted that the most satisfactory results in their series of 42 cases were obtained when a modified acromioplasty was performed, which retained the superficial cortical shell of the os acromiale and its deltoid attachments, in contrast to fragment excision or fusion. With regard to repair of massive rotator cuff tears, Paulos et all I presented a series of 32 patients with either very large or massive rotator cuff tears and significant retraction that were addressed through an acromion splitting approach. Initially described by Kessel and Watson, 13 the approach used by Paulos et al. entailed a lateral deltoid splitting mini-lateral approach with medial extension through the acromion. The exposure afforded by this approach allows for excellent visualization of the cuff with aggressive mobilization while maintaining the integrity of the anterior deltoid insertion to the acromion. Acromion repair was by way of nonabsorbable sutures through drill holes. At an average follow-up of 33.4 months for 38 shoulders, 27 were rated good to excellent, and 11 were rated fair to poor by the UCLA shoulder rating scale. In the case presently described, several of the preceding principles were incorporated in the treatment of our patient. Because of his partial quadriplegia, the patient relied solely on his left upper extremity for carrying out activities of daily living. A massive rotator cuff tear significantly compromised his left shoulder function. Thus, obtaining a satisfactory cuff repair was of great importance. Presence of the very mobile os acromiale further added to the complexity of the case. Considering the findings of Edelson et al., 6 fragment excision was not as favorable an option as fixation/ fusion. Exposure of the rotator cuff utilized the acromion splitting approach as described by Paulos et all I and incorporated the presence of the os acromiale as delineating the region of the osteotomy. Anterior deltoid insertion was maintained and the cuff tear was well exposed to facilitate mobilization and repair. After
655
standard rotator cuff repair techniques, repair of the os fragment combined the suture technique used by Paulos et al.l~ along with interfragmentary screw fixation as used by Edelson et al. 6 Bone grafting was not performed. Preliminary results of the case reveal satisfactory cuff function with early healing across the os acromiale. The patient's symptoms remain well abated. In summary, incorporating previously described principles for treatment of symptomatic os acromiale and surgical exposure for repair of massive rotator cuff tears, an acromion splitting approach through an existing os acromiale with subsequent fragment fixation was used to surgically treat a massive rotator cuff tear with a coexistent os acromiale. This appears to be a viable surgical alternative to treating this complexity of problems based on the preliminary results of this case.
REFERENCES 1. Samilson RL. Congenital and developmental anomalies of the shoulder girdle. Orthop Clin North Am 1980; 11:219-231. 2. Armengol J, Brittis D, Pollock RG, Flatow EL, Self EB, Bigliani LU. The association of an unfused acromial epiphysis with tears of the rotator cuff: A review of 42 cases. Orthop Trans 1994; 17:975-976. 3. Beim GM, Warner JP. Symptomatic os acromiale recognition and treatment. Pittsburgh Orthop J 1996;7:46-51. 4. Bigliani LU, Norris TR, Fischer J, Neer CS. The relationship between the unfused acromial epiphysis and subacromial impingement lesions. Orthop Trans 1983; 7:138. 5. Burkhart SS. Os acromiale in a professional tennis player. Am J Sports Med 1992;20:483-484. 6. Edelson JG, Zuckerman J, Hershkovitz I. Os acromiale: anatomy and surgical implications. J Bone Joint Surg Br 1993;74:551-
555. 7. Hutchinson MR, Beenstra MA. Arthroscopic decompression of shoulder impingement secondary to os acromiale. Arthroscopy 1993;9:28-32. 8. Mudge MK, Wood VE, Frykman GK. Rotator cuff tears associated with os acromiale. J Bone Joint Surg Am 1984;66:427429. 9. Park JG, Lee JK, Phelps CT. Os acromiale associated with rotator cuff impingement: MR imaging of the shoulder. Radiology 1994; 193:255-257. 10. Sterling JC, Meyers MC, Chesshir W, Calvo RD. Os acromiale in a baseball catcher. Med Sci Sports Exerc 1995;27:795-799. 11. Paulos LE, Meislin RJ, Drawbert J. The acromion-splitting approach for large and massive rotator cuff tears. Am J Sports" Med 1994;22:306-312. 12. Liberson F. Os acromiale: A contested anomaly. J Bone Joint Surg 1937; 19:683-689. 13. Kessel L, Watson M. The painful arc syndrome. Clinical classification as a guide to management. J Bone Joint Surg Br 1977; 59:166-172.