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Arthroscopic stabilization of acromioclavicular joint dislocation using the AC graftrope system
J Shoulder Elbow Surg (2010) 19, 47-52
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Arthroscopic stabilization of acromioclavicular joint dislocation using the AC graftrope system Thomas M. DeBerardino, MD*, Michael J. Pensak, MD, Joel Ferreira, MD, Augustus D. Mazzocca, MD From the University of Connecticut Health Center, Farmington, CT Background: Separation of the acromioclavicular joint (ACJ) is a common orthopaedic injury among athletes involved in contact sports and victims of motor vehicle accidents, particularly motorcycle crashes. High-grade ACJ disruptions (type IV-VI) are managed surgically through a variety of procedures. These range from simple plate and screw fixation to more complex procedures involving ligament repair, transfer, and reconstruction. Methods: This paper describes a new technique utilizing a direct subacromial arthroscopic approach to performing a reconstruction of the ruptured coracoclavicular ligaments. The appropriately over-engineered fixation device is made up of a subcoracoid button secured via nonabsorbable sutures to a special clavicular washer and augmented by a centrally placed soft tissue graft. Results: To date, the senior author has performed 10 cases on both acute and chronic high-grade ACJ separations. All patients greater than 6 months out from surgery have returned to their normal pre-injury level of activity. No complications (infection, hardware, or graft failure) have been documented, and all have maintained the interoperative reduction of the acromioclavicular joint and coracoclavicular space. Conclusion: The arthroscopic reconstruction of the AC separation is a low-morbidity, safe, and reproducible operation that provides adequate fixation and stability combined with the use of a soft tissue graft to promote sound biologic healing. Level of Evidence: Review Article Ó 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Acromioclavicular separation; arthroscopic reconstruction; subacromial approach; AC GraftRope System
Separation of the acromioclavicular joint (ACJ) is a common orthopaedic injury among athletes involved in contact sports and victims of motor vehicle accidents, particularly motorcycle crashes. In fact, ACJ dislocation
*Reprint requests: Thomas M. DeBerardino, MD, UConn Health Center, 263 Farmington Ave MARB4, Farmington, CT 06034. E-mail address: [email protected] (T.M. DeBerardino).
accounts for up to 40% of shoulder injuries in elite athletes participating in highly competitive contact sports.6 The mechanism of injury of an AC joint dislocation is typically a direct fall onto the outer aspect of the shoulder with the humerus in adduction. The ACJ is a true synovial joint that is stabilized statically by the acromioclavicular (AC), coracoclavicular (CC), and coracoacromial (CA) ligaments. Each ligament offers stability to differently directed forces, with the AC
1058-2746/2010/$36.00 - see front matter Ó 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2009.12.014
48 and CC ligaments being the most important. The AC ligament, composed of both anterior and posterior portions, provides stability in the anteroposterior plane. The CC ligament complex is comprised of the medial conoid and lateral trapezoid ligaments. These portions of the CC ligament act in concert to resist motion in the vertical plane. Additionally, the CC ligament guides scapulohumeral motion through its attachments to the clavicle and scapula via the coracoid process. Finally, the CA ligament is a strong, typically triangular-shaped ligament that functions mainly as a superior restraint against humeral translation. Classification of AC joint dislocations has followed the Rockwood and Green system, which separates this injury into 6 different types. Type I and II are considered partial dislocations and differ in the amount of damage to the AC ligament and joint capsule. In type I, there is no tear in either the AC or CC ligaments and no instability occurs. In type II, there is rupture of the AC joint capsule and ligaments without damage to the CC ligaments. In types III-VI, there is a disruption to both the AC and CC ligaments; however, the amount of disruption and damage varies greatly. Initial imaging for a suspected AC joint dislocation involves internal and external rotation, scapular Y, and axillary views to fully assess the AC joint. A traditional AP view of the shoulder has limited value as the AC joint is overpenetrated and subtle lesions (types I and II) may be missed.6 Furthermore, authors have recommended a Stryker notch view if a complete AC dislocation is seen with a normal CC interspace, which could indicate possible fracture of the coracoid process.6
Treatment Nonoperative management is the accepted method of treatment for low-grade injuries (types I and II). There is still significant controversy regarding the proper management of type III injuries, as they do not significantly disrupt the dynamic stabilizers of the AC joint. Literature has shown no significant difference between operative and nonoperative treatment, with 1 specific study showing no strength difference at 2-year follow-up.12 One review of 2000 patients with type III AC joint injuries showed nonoperative versus operative satisfactory outcome to be 87% and 88%, respectively.11 As a result, there is a slight trend to initial conservative management with these types of injuries. High-grade ACJ disruptions (types IV-VI) are managed surgically through a variety of procedures. These range from simple plate and screw fixation to more complex procedures involving ligament repair, transfer, and reconstruction. Additionally, these surgical options can be performed through both open and/or newer arthroscopically assisted techniques, underscoring the lack of consensus about the ideal management of these injuries. The goals of surgical treatment of ACJ injuries adhere to the same management principles for dealing with articular
T.M. DeBerardino et al. injuries elsewhere in the body; that is, anatomic reduction and restoration of normal arthrokinematics. This is the best way to minimize complications including pain, loss of reduction, arthrosis, and decreased extremity function. Currently, there are 4 main surgical options for ACJ disruptions: (1) primary ACJ fixation (using pins, screws, suture wires, plates, and hook plates) with or without ligament repair or reconstruction; (2) primary fixation of the coracoclavicular (CC)5 interval with or without acromioclavicular (AC) ligament repair/reconstruction; (3) distal clavicle excision (DCE) with or without CC ligament repair or coracoacromial (CA) ligament transfer; (4) muscle transfers with or without DCE. The continual search for newer techniques to repair ACJ injuries is due in part to the complications associated with the existing surgical options. For example, metal implants have been known to migrate and compromise ACJ reduction .4,5,9 CA ligament transfers do not recreate the native AC joint anatomy and have failure rates as high as 30% in some investigations.14,15 Other attempts to restore the CC ligaments using a screw and suture material are designed to achieve an anatomic fixation but rely on healing of the native CC ligaments.1,10,13 This can be problematic following high-energy injuries with extensive soft tissue damage or chronic ACJ injuries. In these scenarios, the implants come to bear more of the physiologic loads and have a higher propensity to fail. Muscle transfers of the corachobrachialis and biceps are technically demanding, carry significant risks of damaging the musculocutaneous nerve, and can result in failure of the coracoid to heal to the clavicle.3 Standard procedures for ACJ reconstruction require open approaches that have their own inherent risks and complications. Adequate circumferential access to the coracoid process is a prerequisite for CC ligament repair/ reconstruction. This requires detaching part of the deltoid insertion and extensive soft tissue dissection, which can place neurovascular structures at risk while attempting to pass suture or graft material. Moreover, even after the dissection, visibility around the coracoid process may still be suboptimal. As a result, there has been increasing interest in the use of arthroscopically assisted CC ligament6 reconstructions which offer superior visualization of the coracoid base, minimal soft tissue dissection, and smaller incisions while allowing for safe graft passage. The GraftRope consists of a #5 FiberWire suture that makes 4 passes between the coracoid button and clavicular washer, and is designed to accept autograft or allograft semitendinosis, gracilis, or tibialis anterior tendon soft tissue grafts. This device finds application in anatomic restoration of ACJ by traversing the CC interval along the path of the CC ligaments. The GraftRope results in anatomic reduction and restoration of normal arthrokinematics about the ACJ because of its nonrigid fixation. Its comparatively low profile precludes the need for removal of the implant. Additionally, its snowshoe hold on the cortices
Arthroscopic ACJ stabilization
Figure 1 Arthroscopic setup for a left shoulder using lateral viewing and anterolateral working portals in the subacromial space.
of the clavicle and coracoid process means that it should withstand cyclic loading without cutting out from the bone of the ACJ while permitting normal arthrokinematics about the shoulder. Recent biomechanical evidence suggests that reconstructed CC ligaments using a free tendon graft provide initial stability and a load to failure that is equivalent to the intact CC ligaments.2,8 Additionally, preliminary biomechanical data by Mazzocca and Guerra demonstrated that GraftRope repair of the AC joint is a biologic repair that results in similar strength as the native intact ligaments, and results in statistically significant less displacement in the anterior, posterior, and superior directions in response to a 70 N force.7
New surgical technique We describe a technique utilizing a direct subacromial approach developed by the senior author (T.M.D.). The patient is placed in the beach chair position using a Spider Limb Positioner (Tenet Medical, Calgary, Alberta, Canada) to hold the arm in the desired position, especially during the crucial reduction and fixation phase of the operation (Figure 1). In isolated ACJ reconstructive cases, the 30 arthroscope is placed in the subacromial space via a straight lateral portal. An accessory anterolateral portal is established as a working portal to identify the coracoacromial (CA) ligament. Adequate visualization of the anterolateral subacromial space is achieved with the use of a shaver and ablation, cautery, and suction device. At this point, a trial reduction of the clavicle and AC joint is attempted. A combination of direct arthroscopic visualization and mini C128 arm fluoroscopy confirms adequate reduction of the ACJ and coracoclavicular space. In acute cases, only
49 minimal debridement of excessive soft tissue is necessary to allow for anatomic reduction. With chronic cases, up to 5 mm of distal clavicle may also be removed arthroscopically to allow for an anatomic reduction, as described above. The CA ligament serves as the direct visual guide down to the tip of the coracoids. The cautery device is used to expose the lateral inferior aspect of the coracoids down to the normal flare at the base. With undersurface of the base of the coracoids clearly visualized, the drill guide is placed via the anterolateral portal under the base of the coracoids. Care is directed at making sure the guide is centered under the coracoid to avoid eccentric drilling or notching of the coracoids. The drill sleeve of the guide is directed over the lateral clavicle approximately 4-cm medial to the AC joint. A small 2-cm incision is made orthogonal to the axis of the clavicle centered over the posterior aspect of the clavicle.8 Minimal sharp and blunt dissection between the deltoid and trapezius muscles provides direct access to the superior cortex of the clavicle. A special offset guide sleeve is secured to the end of the standard drill sleeve in order to post the offset guide against the posterior cortex of the clavicle and hold the entire drill guide in place. A guide pin for a 6-mm acorn reamer is placed under power through all 4 cortices of the clavicle and coracoid. Once the tip of the guide pin is visualized to exit the inferior aspect of the coracoid at the desired position near its base, the cannulated acorn reamer is used to fashion the 6-mm tunnel. The guide pin is removed and a flexible looped passing wire is delivered down the reamer and retrieved via the anterolateral portal prior to the removal of the cannulated reamer. Graft and implant preparation is completed on the back table. A soft tissue allograft (semitendinosis or tibialis) is commonly used as a looped graft for this reconstructive procedure. The specific AC GraftRopeä System (Arthrex Inc, Naples, FL) is provided as a self-contained kit. With this system, a soft tissue graft is easily secured to the coracoids button and the special cortical washer placed over the clavicle allows for tenodesis screw fixation of the graft to the clavicle. The graft length should be approximately 12-15 cm, and the folded graft should pass through a 4.5-5.5-mm sizing block. If the graft is too wide, simply place the graft longitudinally on a graft board and use a #11 blade knife in line with the tendon fibers to contour its width. The metal clavicle washer and coracoids button are joined by a continuous loop of #5 FiberWire suture (Arthrex Inc., Naples, FL), providing fixation during the healing phase. The looped end of the graft is secured to a hole through a small keel in the coracoid button with another #5 FiberWire suture. The tails of the soft tissue graft are secured with #2 FiberLoop sutures and passed up through9 the center of the clavicle washer. A leading passing suture is placed through one of the holes in the coracoid button to allow easy passage of the construct down through the clavicle and coracoid. The final graft construct must easily pass through a 6-mm sizing tube to avoid complications with graft passage (Figure 2).
50
Figure 2
T.M. DeBerardino et al.
Graft GraftRope construct ready for implantation.
The leading passing suture is delivered through the clavicle and coracoid out the anterolateral portal by the flexible passing wire (Figure 3). The coracoid button and looped end of the adjoined soft tissue graft is delivered out the base of the coracoids, thus allowing the button to flip to sit in the desired position. A forked probe or similar suture retriever can be used to facilitate delivery of the coracoid button and graft through the coracoid by providing leverage on the passing suture like a pulley beneath the coracoid. Final reduction is obtained again with direct visualization arthroscopically and mini C-arm prior to securing the washer and graft to the clavicle (Figure 4). Once adequate reduction is obtained, the free ends of the exiting #5 FiberWire suture are tied together over the washer, making sure to take up all the slack within the 4 passes of the suture between the button and washer. A 5.5-mm 12-mm PEEK screw (Arthrex, Inc.) is then placed as an interference screw between the tensioned graft limbs for final construct fixation. In routine cases, the long exiting soft tissue graft tails can be cut flush above the washer. Alternatively, in more unstable cases, the graft tails can be passed subcutaneously under the lateral wound edge and secured with permanent sutures to the stout periosteal and capsular tissue over the medial aspect of the acromion. Small suture anchors can also provide fixation for the graft tails to the medial aspect of the acromion. These simple techniques help augment the injured posterosuperior AC joint capsular fibers that are known to be important for horizontal ACJ stability. A 3-phase rehabilitation program begins immediately postoperatively. Phase I is from 0-4 weeks and is the protective phase. The patient wears the fitted postoperative sling with a firm foam pillow for comfort for 4 weeks to alleviate unwanted gravity-derived forces on the graft and implant and to promote healing. Phase II is from 4 to 12 weeks and focuses on a gradual regaining of normal shoulder range of motion and resistive strengthening exercises. Strengthening exercises are implemented using graduated tubing. Flexion and abduction strengthening is allowed with the shoulder limited to 90 of elevation. External and
Figure 3 Graft passage through clavicle down through the base of coracoid.
internal rotation strengthening are allowed in a neutral position. Phase III is from 12 to 24 weeks and focuses on the functional return back to sport and work activities.
Early clinical results To date, the senior author has performed 10 cases on both acute and chronic high-grade ACJ separations. All patients greater than 6 months out from surgery have returned to their normal pre-injury level of activity. No complications (infection, hardware, or graft failure) have been documented and all have maintained the interoperative reduction of the acromioclavicular joint and coracoclavicular space.
Discussion The goals of surgical treatment of ACJ injuries adhere to the same management principles for dealing with articular injuries elsewhere in the body; that is, anatomic reduction and restoration of normal arthrokinematics. This is the best way to minimize complications including pain, loss of reduction, arthrosis and decreased extremity function. Currently, there are 4 main surgical options for ACJ disruptions: (1) primary ACJ fixation (using pins, screws, suture wires, plates, and hook plates) with or without ligament repair or reconstruction;
Arthroscopic ACJ stabilization
Figure 4
51
Final arthroscopic view of coracoid button (A) and final reduction via mini C307 arm (B).
(2) primary fixation of the coracoclavicular (CC) interval with or without acromioclavicular (AC) ligament repair/reconstruction; (3) distal clavicle excision (DCE) with or without CC ligament repair, or coracoacromial (CA) ligament transfer; (4) muscle transfers with or without DCE. The continual search for newer techniques to repair ACJ injuries is due in part to the complications associated with the existing surgical options. For example, metal implants have been known to migrate and compromise ACJ reduction.3-5,9 CA ligament transfers do not recreate the native AC joint anatomy and have failure rates as high as 30% in some investigations.1, 2 Other attempts to restore the CC ligaments using a screw and suture material are designed to achieve an anatomic fixation but rely on healing of the native CC ligaments.3-5 This can be problematic following high-energy injuries with extensive soft tissue damage or chronic ACJ injuries. In these scenarios, the implants come to bear more of the physiologic loads and have a higher propensity to fail. Muscle transfers of the coracobrachialis and biceps are technically demanding, carry significant risks of damaging the musculocutaneous nerve, and can result in failure of the coracoid to heal to the clavicle.6,13 Standard procedures for ACJ reconstruction require open approaches that have their own inherent risks and complications. Adequate circumferential access to the coracoid process is a prerequisite for CC ligament repair/reconstruction. This requires detaching part of the deltoid insertion and extensive soft tissue dissection which can place neurovascular structures at risk while attempting to pass suture or graft material. Moreover, even after the dissection, visibility around the coracoid process may still be suboptimal. As a result, there has been increasing interest in the use of arthroscopic ally assisted CC ligament reconstructions which offer superior visualization of the coracoid base, minimal soft tissue dissection, and smaller incisions while allowing for safe graft passage. The GraftRope consists of a # 5 FiberWire suture that makes 4 passes between the coracoid button and clavicular washer, and is designed to accept autograft or allograft semitendinosis, gracilis, or tibialis anterior tendon soft tissue grafts. This device finds application in anatomic
restoration of ACJ by traversing the CC interval along the path of the CC ligaments.
Conclusion The GraftRope results in anatomic reduction and restoration of normal arthrokinematics about the ACJ because of its nonrigid fixation. Its comparatively low profile precludes the need for removal of the implant. Additionally, its snow shoe hold on the cortices of the clavicle and coracoid process means that it should withstand cyclic loading without cutting out from the bone of the ACJ while permitting normal arthrokinematics about the shoulder. Recent biomechanical evidence suggests that reconstructed CC ligaments using a free tendon graft provide initial stability and a load to failure that is equivalent to the intact CC ligaments.7,10 Additionally, preliminary biomechanical data by Mazzocca et al demonstrated that GraftRope reconstruction of the AC joint is a biologic repair that results in similar strength as the native intact ligaments, and results in statistically significant less displacement in the anterior, posterior, and superior directions in response to a 70 N force.8 The AC GraftRope System described above improves upon many of the limitations of previously described techniques in stabilizing ACJ dislocations; namely, poor visualization of the area needed for adequate reduction, large soft tissue dissection, and use of metallic implants. Also, avoidance of an open procedure lessens the risk of infection and wound healing concerns. When compared to the Graftrope, metallic implants are bulkier and more pronounced under the skin, which may be cosmetically displeasing to the patient. The main advantage of the Graftrope system is its ability to achieve anatomic reduction and restoration of normal arthrokinematics via a nonrigid fixation. It also avoids the potential nerve injury seen with muscle transfers and does not rely on healing of an already damaged ligament as seen in CC ligament repair with suture.
52
Disclaimer T.M.D. and A.D.M. are clinical consultants for Arthrex, Inc., which is related to the subject of this work. Both A.D.M. and T.M.D. receive research support in the form of supplies and financial support to conduct ongoing research. No funding was received for this study.
References 1. Bosworth BM. Acromioclavicular separation: new method for repair. Surg Gynecol Obstet 1941;73:866-71. 2. Lee SJ, Nicholas SJ, Akizuki KH, McHugh MP, Kremenic IJ, Ben-Avi S. Reconstruction of the coracoclavicular ligament with tendon grafts: a comparative biomechanical study. Am J Sports Med 2003;31:648-54. 3. Lim YW, Sood A, van Riet RP, Bain GI. Acromioclavicular joint reduction, repair and reconstruction using metallic buttonseEarly results and complications. Tech Shoulder Elbow Surg 2007;8:213-21. 4. Lindsey RW, Gutowski WT. The migration of a broken pin following fixation of the acromioclavicular joint: a case report and review of literature. Orthopaedics 1986;9:413-6. 5. Lyons FA, Rockwood CA. Migration of pins used in operations on the shoulder. J Bone Joint Surg Am 1990;72:1262-7.
T.M. DeBerardino et al. 6. Mazzocca AD, Arciero RA, Bicos J. Evaluation and treatment of acromioclavicular injuries. Am J Sports Med 2007;35:316-29. 7. Mazzocca AD, Guerra J. Biomechanical Testing of AC Graft Repairs, University of Connecticut Health Center. 8. Mazzocca AD, Santangelo SA, Johnson ST, Rios CG, Dumonski ML, Arciero RA. A biomechanical evaluation of an anatomical coracoclavicular ligament reconstruction. Am J Sports Med 2006;34: 236-46. 9. Norrell H, Llewellyn RC. Migration of a threaded Steinman pin from the acromioclavicular joint to the spinal canal: a case report. J Bone Joint Surg 1965;47A:1024-6. 10. Osti M, Seil R, Bachelier F, Kohn D. Minimally invasive endoscopic reconstruction technique of acute AC-joint dislocations: a cadaver study. Knee Surg Sports Traumatol Arthrosc 2006;14: 686-91. 11. Phillips A, Smart C, Groom A. Acromioclavicular dislocations: conservative or surgical therapy. Clin Orthop Relat Res 1998;353:10-7. 12. Tibone J, Sellers R, Tonino P. Strength testing after third-degree acromioclavicular dislocations. Am J Sports Med 1992;20:328-31. 13. Tsou PM. Percutaneous cannulated screw coracoclavicular fixation for acute acromioclavicular dislocations. Clin Orthop Relat Res 1989;243: 112-21. 14. Weaver JK, Dunn HK. Treatment of acromioclavicular injuries, especially complete acromioclavicular separation. J Bone Joint Surg Am 1972;54:1187-94. 15. Weinstein DM, McCann PD, McIIveen SJ, Flatow EL, Bigliani LU. Surgical treatment of complete acromioclavicular dislocations. Am J Sports Med 1995;23:324-31.
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Arthroscopic stabilization of acromioclavicular joint dislocation using the AC graftrope system Thomas M. DeBerardino, MD*, Michael J. Pensak, MD, Joel Ferreira, MD, Augustus D. Mazzocca, MD From the University of Connecticut Health Center, Farmington, CT Background: Separation of the acromioclavicular joint (ACJ) is a common orthopaedic injury among athletes involved in contact sports and victims of motor vehicle accidents, particularly motorcycle crashes. High-grade ACJ disruptions (type IV-VI) are managed surgically through a variety of procedures. These range from simple plate and screw fixation to more complex procedures involving ligament repair, transfer, and reconstruction. Methods: This paper describes a new technique utilizing a direct subacromial arthroscopic approach to performing a reconstruction of the ruptured coracoclavicular ligaments. The appropriately over-engineered fixation device is made up of a subcoracoid button secured via nonabsorbable sutures to a special clavicular washer and augmented by a centrally placed soft tissue graft. Results: To date, the senior author has performed 10 cases on both acute and chronic high-grade ACJ separations. All patients greater than 6 months out from surgery have returned to their normal pre-injury level of activity. No complications (infection, hardware, or graft failure) have been documented, and all have maintained the interoperative reduction of the acromioclavicular joint and coracoclavicular space. Conclusion: The arthroscopic reconstruction of the AC separation is a low-morbidity, safe, and reproducible operation that provides adequate fixation and stability combined with the use of a soft tissue graft to promote sound biologic healing. Level of Evidence: Review Article Ó 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Acromioclavicular separation; arthroscopic reconstruction; subacromial approach; AC GraftRope System
Separation of the acromioclavicular joint (ACJ) is a common orthopaedic injury among athletes involved in contact sports and victims of motor vehicle accidents, particularly motorcycle crashes. In fact, ACJ dislocation
*Reprint requests: Thomas M. DeBerardino, MD, UConn Health Center, 263 Farmington Ave MARB4, Farmington, CT 06034. E-mail address: [email protected] (T.M. DeBerardino).
accounts for up to 40% of shoulder injuries in elite athletes participating in highly competitive contact sports.6 The mechanism of injury of an AC joint dislocation is typically a direct fall onto the outer aspect of the shoulder with the humerus in adduction. The ACJ is a true synovial joint that is stabilized statically by the acromioclavicular (AC), coracoclavicular (CC), and coracoacromial (CA) ligaments. Each ligament offers stability to differently directed forces, with the AC
1058-2746/2010/$36.00 - see front matter Ó 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. doi:10.1016/j.jse.2009.12.014
48 and CC ligaments being the most important. The AC ligament, composed of both anterior and posterior portions, provides stability in the anteroposterior plane. The CC ligament complex is comprised of the medial conoid and lateral trapezoid ligaments. These portions of the CC ligament act in concert to resist motion in the vertical plane. Additionally, the CC ligament guides scapulohumeral motion through its attachments to the clavicle and scapula via the coracoid process. Finally, the CA ligament is a strong, typically triangular-shaped ligament that functions mainly as a superior restraint against humeral translation. Classification of AC joint dislocations has followed the Rockwood and Green system, which separates this injury into 6 different types. Type I and II are considered partial dislocations and differ in the amount of damage to the AC ligament and joint capsule. In type I, there is no tear in either the AC or CC ligaments and no instability occurs. In type II, there is rupture of the AC joint capsule and ligaments without damage to the CC ligaments. In types III-VI, there is a disruption to both the AC and CC ligaments; however, the amount of disruption and damage varies greatly. Initial imaging for a suspected AC joint dislocation involves internal and external rotation, scapular Y, and axillary views to fully assess the AC joint. A traditional AP view of the shoulder has limited value as the AC joint is overpenetrated and subtle lesions (types I and II) may be missed.6 Furthermore, authors have recommended a Stryker notch view if a complete AC dislocation is seen with a normal CC interspace, which could indicate possible fracture of the coracoid process.6
Treatment Nonoperative management is the accepted method of treatment for low-grade injuries (types I and II). There is still significant controversy regarding the proper management of type III injuries, as they do not significantly disrupt the dynamic stabilizers of the AC joint. Literature has shown no significant difference between operative and nonoperative treatment, with 1 specific study showing no strength difference at 2-year follow-up.12 One review of 2000 patients with type III AC joint injuries showed nonoperative versus operative satisfactory outcome to be 87% and 88%, respectively.11 As a result, there is a slight trend to initial conservative management with these types of injuries. High-grade ACJ disruptions (types IV-VI) are managed surgically through a variety of procedures. These range from simple plate and screw fixation to more complex procedures involving ligament repair, transfer, and reconstruction. Additionally, these surgical options can be performed through both open and/or newer arthroscopically assisted techniques, underscoring the lack of consensus about the ideal management of these injuries. The goals of surgical treatment of ACJ injuries adhere to the same management principles for dealing with articular
T.M. DeBerardino et al. injuries elsewhere in the body; that is, anatomic reduction and restoration of normal arthrokinematics. This is the best way to minimize complications including pain, loss of reduction, arthrosis, and decreased extremity function. Currently, there are 4 main surgical options for ACJ disruptions: (1) primary ACJ fixation (using pins, screws, suture wires, plates, and hook plates) with or without ligament repair or reconstruction; (2) primary fixation of the coracoclavicular (CC)5 interval with or without acromioclavicular (AC) ligament repair/reconstruction; (3) distal clavicle excision (DCE) with or without CC ligament repair or coracoacromial (CA) ligament transfer; (4) muscle transfers with or without DCE. The continual search for newer techniques to repair ACJ injuries is due in part to the complications associated with the existing surgical options. For example, metal implants have been known to migrate and compromise ACJ reduction .4,5,9 CA ligament transfers do not recreate the native AC joint anatomy and have failure rates as high as 30% in some investigations.14,15 Other attempts to restore the CC ligaments using a screw and suture material are designed to achieve an anatomic fixation but rely on healing of the native CC ligaments.1,10,13 This can be problematic following high-energy injuries with extensive soft tissue damage or chronic ACJ injuries. In these scenarios, the implants come to bear more of the physiologic loads and have a higher propensity to fail. Muscle transfers of the corachobrachialis and biceps are technically demanding, carry significant risks of damaging the musculocutaneous nerve, and can result in failure of the coracoid to heal to the clavicle.3 Standard procedures for ACJ reconstruction require open approaches that have their own inherent risks and complications. Adequate circumferential access to the coracoid process is a prerequisite for CC ligament repair/ reconstruction. This requires detaching part of the deltoid insertion and extensive soft tissue dissection, which can place neurovascular structures at risk while attempting to pass suture or graft material. Moreover, even after the dissection, visibility around the coracoid process may still be suboptimal. As a result, there has been increasing interest in the use of arthroscopically assisted CC ligament6 reconstructions which offer superior visualization of the coracoid base, minimal soft tissue dissection, and smaller incisions while allowing for safe graft passage. The GraftRope consists of a #5 FiberWire suture that makes 4 passes between the coracoid button and clavicular washer, and is designed to accept autograft or allograft semitendinosis, gracilis, or tibialis anterior tendon soft tissue grafts. This device finds application in anatomic restoration of ACJ by traversing the CC interval along the path of the CC ligaments. The GraftRope results in anatomic reduction and restoration of normal arthrokinematics about the ACJ because of its nonrigid fixation. Its comparatively low profile precludes the need for removal of the implant. Additionally, its snowshoe hold on the cortices
Arthroscopic ACJ stabilization
Figure 1 Arthroscopic setup for a left shoulder using lateral viewing and anterolateral working portals in the subacromial space.
of the clavicle and coracoid process means that it should withstand cyclic loading without cutting out from the bone of the ACJ while permitting normal arthrokinematics about the shoulder. Recent biomechanical evidence suggests that reconstructed CC ligaments using a free tendon graft provide initial stability and a load to failure that is equivalent to the intact CC ligaments.2,8 Additionally, preliminary biomechanical data by Mazzocca and Guerra demonstrated that GraftRope repair of the AC joint is a biologic repair that results in similar strength as the native intact ligaments, and results in statistically significant less displacement in the anterior, posterior, and superior directions in response to a 70 N force.7
New surgical technique We describe a technique utilizing a direct subacromial approach developed by the senior author (T.M.D.). The patient is placed in the beach chair position using a Spider Limb Positioner (Tenet Medical, Calgary, Alberta, Canada) to hold the arm in the desired position, especially during the crucial reduction and fixation phase of the operation (Figure 1). In isolated ACJ reconstructive cases, the 30 arthroscope is placed in the subacromial space via a straight lateral portal. An accessory anterolateral portal is established as a working portal to identify the coracoacromial (CA) ligament. Adequate visualization of the anterolateral subacromial space is achieved with the use of a shaver and ablation, cautery, and suction device. At this point, a trial reduction of the clavicle and AC joint is attempted. A combination of direct arthroscopic visualization and mini C128 arm fluoroscopy confirms adequate reduction of the ACJ and coracoclavicular space. In acute cases, only
49 minimal debridement of excessive soft tissue is necessary to allow for anatomic reduction. With chronic cases, up to 5 mm of distal clavicle may also be removed arthroscopically to allow for an anatomic reduction, as described above. The CA ligament serves as the direct visual guide down to the tip of the coracoids. The cautery device is used to expose the lateral inferior aspect of the coracoids down to the normal flare at the base. With undersurface of the base of the coracoids clearly visualized, the drill guide is placed via the anterolateral portal under the base of the coracoids. Care is directed at making sure the guide is centered under the coracoid to avoid eccentric drilling or notching of the coracoids. The drill sleeve of the guide is directed over the lateral clavicle approximately 4-cm medial to the AC joint. A small 2-cm incision is made orthogonal to the axis of the clavicle centered over the posterior aspect of the clavicle.8 Minimal sharp and blunt dissection between the deltoid and trapezius muscles provides direct access to the superior cortex of the clavicle. A special offset guide sleeve is secured to the end of the standard drill sleeve in order to post the offset guide against the posterior cortex of the clavicle and hold the entire drill guide in place. A guide pin for a 6-mm acorn reamer is placed under power through all 4 cortices of the clavicle and coracoid. Once the tip of the guide pin is visualized to exit the inferior aspect of the coracoid at the desired position near its base, the cannulated acorn reamer is used to fashion the 6-mm tunnel. The guide pin is removed and a flexible looped passing wire is delivered down the reamer and retrieved via the anterolateral portal prior to the removal of the cannulated reamer. Graft and implant preparation is completed on the back table. A soft tissue allograft (semitendinosis or tibialis) is commonly used as a looped graft for this reconstructive procedure. The specific AC GraftRopeä System (Arthrex Inc, Naples, FL) is provided as a self-contained kit. With this system, a soft tissue graft is easily secured to the coracoids button and the special cortical washer placed over the clavicle allows for tenodesis screw fixation of the graft to the clavicle. The graft length should be approximately 12-15 cm, and the folded graft should pass through a 4.5-5.5-mm sizing block. If the graft is too wide, simply place the graft longitudinally on a graft board and use a #11 blade knife in line with the tendon fibers to contour its width. The metal clavicle washer and coracoids button are joined by a continuous loop of #5 FiberWire suture (Arthrex Inc., Naples, FL), providing fixation during the healing phase. The looped end of the graft is secured to a hole through a small keel in the coracoid button with another #5 FiberWire suture. The tails of the soft tissue graft are secured with #2 FiberLoop sutures and passed up through9 the center of the clavicle washer. A leading passing suture is placed through one of the holes in the coracoid button to allow easy passage of the construct down through the clavicle and coracoid. The final graft construct must easily pass through a 6-mm sizing tube to avoid complications with graft passage (Figure 2).
50
Figure 2
T.M. DeBerardino et al.
Graft GraftRope construct ready for implantation.
The leading passing suture is delivered through the clavicle and coracoid out the anterolateral portal by the flexible passing wire (Figure 3). The coracoid button and looped end of the adjoined soft tissue graft is delivered out the base of the coracoids, thus allowing the button to flip to sit in the desired position. A forked probe or similar suture retriever can be used to facilitate delivery of the coracoid button and graft through the coracoid by providing leverage on the passing suture like a pulley beneath the coracoid. Final reduction is obtained again with direct visualization arthroscopically and mini C-arm prior to securing the washer and graft to the clavicle (Figure 4). Once adequate reduction is obtained, the free ends of the exiting #5 FiberWire suture are tied together over the washer, making sure to take up all the slack within the 4 passes of the suture between the button and washer. A 5.5-mm 12-mm PEEK screw (Arthrex, Inc.) is then placed as an interference screw between the tensioned graft limbs for final construct fixation. In routine cases, the long exiting soft tissue graft tails can be cut flush above the washer. Alternatively, in more unstable cases, the graft tails can be passed subcutaneously under the lateral wound edge and secured with permanent sutures to the stout periosteal and capsular tissue over the medial aspect of the acromion. Small suture anchors can also provide fixation for the graft tails to the medial aspect of the acromion. These simple techniques help augment the injured posterosuperior AC joint capsular fibers that are known to be important for horizontal ACJ stability. A 3-phase rehabilitation program begins immediately postoperatively. Phase I is from 0-4 weeks and is the protective phase. The patient wears the fitted postoperative sling with a firm foam pillow for comfort for 4 weeks to alleviate unwanted gravity-derived forces on the graft and implant and to promote healing. Phase II is from 4 to 12 weeks and focuses on a gradual regaining of normal shoulder range of motion and resistive strengthening exercises. Strengthening exercises are implemented using graduated tubing. Flexion and abduction strengthening is allowed with the shoulder limited to 90 of elevation. External and
Figure 3 Graft passage through clavicle down through the base of coracoid.
internal rotation strengthening are allowed in a neutral position. Phase III is from 12 to 24 weeks and focuses on the functional return back to sport and work activities.
Early clinical results To date, the senior author has performed 10 cases on both acute and chronic high-grade ACJ separations. All patients greater than 6 months out from surgery have returned to their normal pre-injury level of activity. No complications (infection, hardware, or graft failure) have been documented and all have maintained the interoperative reduction of the acromioclavicular joint and coracoclavicular space.
Discussion The goals of surgical treatment of ACJ injuries adhere to the same management principles for dealing with articular injuries elsewhere in the body; that is, anatomic reduction and restoration of normal arthrokinematics. This is the best way to minimize complications including pain, loss of reduction, arthrosis and decreased extremity function. Currently, there are 4 main surgical options for ACJ disruptions: (1) primary ACJ fixation (using pins, screws, suture wires, plates, and hook plates) with or without ligament repair or reconstruction;
Arthroscopic ACJ stabilization
Figure 4
51
Final arthroscopic view of coracoid button (A) and final reduction via mini C307 arm (B).
(2) primary fixation of the coracoclavicular (CC) interval with or without acromioclavicular (AC) ligament repair/reconstruction; (3) distal clavicle excision (DCE) with or without CC ligament repair, or coracoacromial (CA) ligament transfer; (4) muscle transfers with or without DCE. The continual search for newer techniques to repair ACJ injuries is due in part to the complications associated with the existing surgical options. For example, metal implants have been known to migrate and compromise ACJ reduction.3-5,9 CA ligament transfers do not recreate the native AC joint anatomy and have failure rates as high as 30% in some investigations.1, 2 Other attempts to restore the CC ligaments using a screw and suture material are designed to achieve an anatomic fixation but rely on healing of the native CC ligaments.3-5 This can be problematic following high-energy injuries with extensive soft tissue damage or chronic ACJ injuries. In these scenarios, the implants come to bear more of the physiologic loads and have a higher propensity to fail. Muscle transfers of the coracobrachialis and biceps are technically demanding, carry significant risks of damaging the musculocutaneous nerve, and can result in failure of the coracoid to heal to the clavicle.6,13 Standard procedures for ACJ reconstruction require open approaches that have their own inherent risks and complications. Adequate circumferential access to the coracoid process is a prerequisite for CC ligament repair/reconstruction. This requires detaching part of the deltoid insertion and extensive soft tissue dissection which can place neurovascular structures at risk while attempting to pass suture or graft material. Moreover, even after the dissection, visibility around the coracoid process may still be suboptimal. As a result, there has been increasing interest in the use of arthroscopic ally assisted CC ligament reconstructions which offer superior visualization of the coracoid base, minimal soft tissue dissection, and smaller incisions while allowing for safe graft passage. The GraftRope consists of a # 5 FiberWire suture that makes 4 passes between the coracoid button and clavicular washer, and is designed to accept autograft or allograft semitendinosis, gracilis, or tibialis anterior tendon soft tissue grafts. This device finds application in anatomic
restoration of ACJ by traversing the CC interval along the path of the CC ligaments.
Conclusion The GraftRope results in anatomic reduction and restoration of normal arthrokinematics about the ACJ because of its nonrigid fixation. Its comparatively low profile precludes the need for removal of the implant. Additionally, its snow shoe hold on the cortices of the clavicle and coracoid process means that it should withstand cyclic loading without cutting out from the bone of the ACJ while permitting normal arthrokinematics about the shoulder. Recent biomechanical evidence suggests that reconstructed CC ligaments using a free tendon graft provide initial stability and a load to failure that is equivalent to the intact CC ligaments.7,10 Additionally, preliminary biomechanical data by Mazzocca et al demonstrated that GraftRope reconstruction of the AC joint is a biologic repair that results in similar strength as the native intact ligaments, and results in statistically significant less displacement in the anterior, posterior, and superior directions in response to a 70 N force.8 The AC GraftRope System described above improves upon many of the limitations of previously described techniques in stabilizing ACJ dislocations; namely, poor visualization of the area needed for adequate reduction, large soft tissue dissection, and use of metallic implants. Also, avoidance of an open procedure lessens the risk of infection and wound healing concerns. When compared to the Graftrope, metallic implants are bulkier and more pronounced under the skin, which may be cosmetically displeasing to the patient. The main advantage of the Graftrope system is its ability to achieve anatomic reduction and restoration of normal arthrokinematics via a nonrigid fixation. It also avoids the potential nerve injury seen with muscle transfers and does not rely on healing of an already damaged ligament as seen in CC ligament repair with suture.
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Disclaimer T.M.D. and A.D.M. are clinical consultants for Arthrex, Inc., which is related to the subject of this work. Both A.D.M. and T.M.D. receive research support in the form of supplies and financial support to conduct ongoing research. No funding was received for this study.
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