Acromioclavicular Joint Reduction, Repair and Reconstruction Using Metallic ButtonsVEarly Results and Complications

Transcription

1 Techniques in Shoulder & Elbow Surgery 8(4): , 2007 R E V I E W Acromioclavicular Joint Reduction, Repair and Reconstruction Using Metallic ButtonsVEarly Results and Complications Yeow Wai Lim, MBBS, MMed (Surg), FRCSEd (Ortho) Changi General Hospital Singapore, Singapore and Modbury Public Hospital Adelaide, Australia Aman Sood, MBBS University of Adelaide and Royal Adelaide Hospital Adelaide, Australia Roger P. van Riet, MD, PhD, and Gregory I. Bain, MBBS, FRACS, FA (OrthA) Modbury Public Hospital University of Adelaide and Royal Adelaide Hospital Adelaide, Australia * 2007 Lippincott Williams & Wilkins, Philadelphia ABSTRACT Acromioclavicular joint (ACJ) dislocation is a common injury often affecting young adults. Its sequalae range from an asymptomatic shoulder to one that is painful with significant loss of strength in the affected upper limb. The management of ACJ dislocation has revolved around expert neglect for asymptomatic low-grade dislocation to complex surgical reconstruction. The authors describe their early experience with a new technique to reduce and maintain reduction of the coracoclavicular interval using a low-profile doublemetallic button technique (Tightrope; Arthrex Inc, Naples, Fla). The fixation device comprises of a no. 5 Fibrewire suture that is tensioned and secured at both ends by metallic buttons against the cortices of the clavicle and the coracoid. The proposed advantages include a non rigid fixation of the AC joint that maintains reduction yet allowing for normal movement at the joint. The Bsnow shoe[ hold on cortical bone means that the implant should withstand cyclic loading without cutting out from the bone. With these reasons, and because it is relatively low profile, there is no need for removal of implant. Reprints: Gregory I. Bain, MBBS, FRACS, FA (OrthA) 196 Melbourne St, North Adelaide, South Australia 5006, Australia ( greg@ gregbain.com.au). The authors have used this fixation technique on 8 patients. All the patients had strong intraoperative fixation. Immediate and 2-week postoperative radiographs demonstrated excellent reduction of the coracoclavicular interval and the AC joint. However, there were 4 patients with loss of reduction between 2 and 6 weeks postoperatively without additional injury. The mode of fixation failure is unclear at present. While the concept of metallic button fixation may have promise, the authors recommend further biomechanical assessment to evaluate potential weak link of the implant before its clinical use. Keywords: acromioclavicular, new technique, metallic buttons, Tightrope, joint fixation HISTORICAL PERSPECTIVE Acromioclavicular joint (ACJ) dislocation is a common injury often affecting young adults. Its sequalae range from an asymptomatic shoulder to one that is painful, with significant loss of strength in the affected upper limb. Acromioclavicular dislocation was recognized as early as 400 BC by Hippocrates. He suggested a compressive bandage in an attempt to hold the lateral end of the clavicle in a reduced position. Galen (129 AD), almost 600 years later, documented his own AC dislocation that he sustained while wrestling. In the modern era, this injury is better recognized, but its treatment remains a source of great controversy. Volume 8, Issue 4 213

2 Lim et al FIGURE 1. Tightrope implant. Used with permission of Arthrex Inc, Naples, Fla. The management of ACJ dislocation has revolved around expert neglect for asymptomatic low-grade dislocation to complex surgical reconstruction. Currently, there are 4 main surgical treatment options for the dislocated ACJ: (1) primary ACJ fixation (with pins, screws, suture wires, plates, hook plates) with or without ligament repair or reconstruction 1 ; (2) primary coracoclavicular interval fixation (with Bosworth screw, wire, fascia, conjoint tendon, or synthetic sutures) with or without incorporation of AC ligament repair/ reconstruction 2,3 ; (3) excision of the distal clavicle with or without coracoclavicular ligament repair with fascia or suture, or coracoacromial ligament transfer 4Y6 ;(4) dynamic muscle transfers with or without excision of the distal clavicle. 7 The multitude of techniques described illustrates the fact that the ideal technique to treat a symptomatic ACJ dislocation remains to be found. The use of metal implants can be complicated by migration of these implants. 8Y10 Muscle transfers are technically demanding and serve to dynamically pull the clavicle downward through the action of the coracobrachialis and the biceps muscles. However, in dislocation of the ACJ, the problem is one of a Bsagging[ upper limb and not a highriding clavicle. Hence, the pathologic finding is not addressed by muscle transfer procedures. Furthermore, these procedures carry significant chance of injury to the musculocutaneous nerve, failure of the coracoid to heal to the clavicle or loss of screw fixation or screw breakage. We describe a technique to reduce and maintain reduction of the ACJ with the use a low-profile doublebutton technique (Tightrope) composed of a no. 5 Fibrewire suture that is tensioned and secured at both ends by metallic buttons against the cortices of the clavicle and the coracoid (Fig. 1). The proximal end comprises a round metallic button with 4 holes, and the distal end has an oval metallic button with 2 larger holes. The proposed advantages include a nonrigid fixation of the ACJ that maintains reduction, yet allowing for normal movement at the joint. The snow shoe hold on cortical bone means that the implant should withstand cyclic loading without cutting out from the bone. With these reasons, and because it is relatively low profile, there is no need for removal of implant. This implant was originally designed for the repair of the syndesmotic joint in the ankle, but subsequently has also been suggested for closing the coracoclavicular interval in patients with ACJ dislocation. The Tightrope uses the principle of the Endobutton system (Acuflex; Microsurgical Inc, Mansfield, Mass), which has been widely used for anterior cruciate ligament reconstruction. The senior author (G.I.B.) has used the Endobutton technique for surgical repair of distal biceps rupture. 11 The Endobutton technique has also been used for repair of chronic biceps tendon ruptures with supplemental hamstring graft. 12 Biomechanical studies have demonstrated that it is superior to other fixation techniques for the anterior cruciate ligament and the distal biceps tendon. 13 INDICATIONS/CONTRAINDICATIONS Most articles in the literature have supported conservative management for Rockwood grade 1 and 2 injuries, 14 whereas there is a general consensus that grade 4, 5 and 6 injuries 15 are best treated with surgery 16 (Table 1). The management of grade 3 injuries, however, remains controversial, with proponents for and against surgical treatment. 1,17Y19 The authors have used this technique for acute ACJ dislocations (G4 weeks), lateral clavicle fractures with increased coracoclavicular interval, and as an adjunct fixation for chronic ACJ dislocations, in addition to ligamentous reconstruction using hamstrings autograft. In lateral clavicle fractures, a plate bridges the fracture, and the device is then used through the plate to stabilize the coracoclavicular interval. The contraindications for the use of this technique include coracoid fractures, lack of soft tissue coverage, and ongoing infections. Both metallic buttons need an intact cortex to be able to provide stable fixation. PREOPERATIVE PLANNING Preoperative radiographic assessment of the patients included anteroposterior, Y-scapular, axillary views, and azanca 20 view of the ACJ. These views allow assessment of the severity of the dislocation and any associated clavicle fracture. Weight-bearing views can assist in identifying and differentiating between type 1 and 2 ACJ 214 Techniques in Shoulder & Elbow Surgery

3 ACJ Reduction, Repair, and Reconstruction TABLE 1. Rockwood Classification of ACJ Injuries Type Ligaments Involved X-rays Treatment Option 1 AC ligament sprain Normal Conservative 2 AC ligament disrupted Slight increase in the CC interspace (G25% Conservative CC ligament sprain greater than the normal shoulder) 3 AC and CC ligament disrupted Increase in CC interspace of 25% to 100% Conservative or Deltoid and trapezius detached from distal end of the clavicle greater than the normal shoulder surgical 4 AC and CC ligament disrupted Distal end of the clavicle displaced posterior Surgical Deltoid and trapezius detached from distal end of the clavicle Clavicle displaced posteriorly into or through the trapezius to the acromion 5 AC and CC ligament disrupted Increase in CC interspace of 100% to 300% Surgical Deltoid and trapezius detached from distal half of the clavicle greater than the normal shoulder 6 AC and CC ligament disrupted Distal end of the clavicle displaced inferior Surgical Deltoid and trapezius detached from distal half of the clavicle Clavicle displaced inferior to the acromion or coracoid to the acromion or coracoid process CC indicates coracoclavicular; AC, Acromioclavicular. injuries. However, this differentiation is not important in clinical practice and, in the authors view, are not useful for the preoperative planning.type3to4injuriesare easily diagnosed on plain radiographs. TECHNIQUE Acute Cases The patient is given general anesthesia and placed in a beach chair position. A saber-cut incision is made spanning from the clavicle to just inferior to the coracoid process. The supraclavicular nerves are identified and protected throughout the procedure. The trapeziusdeltoid fascia is opened transversely. The deltoid is dissected off the anterosuperior clavicle subperiosteally, allowing visualization of the coracoid process and the acromioclavicular joint. A deltoid split can be performed in line with its fibers if additional exposure is needed. Care should be taken not to damage the coracoacromial ligament when dissecting the area between the clavicle and the coracoid. The trapezoid component of the coracoclavicular ligament spans from the superior surface of the posterior half of the coracoid process. The conoid component is attached to the Bcoracoid knuckle[ just posterior to the trapezoid attachment and runs cranially in an inverse cone shape to attach to the posterior margin of the clavicle at the junction of the middle and lateral one thirds. In acute cases, the ACJ is usually easily reduced. This reduction is then maintained with direct pressure or a clamp. The medial and lateral borders of the coracoid process are identified. A 3.65-mm drill bit (supplied in kit) is positioned on the superior aspect of the clavicle such that it can be drilled in a straight line through the 4 cortices of the clavicle and the coracoid (Figs. 2 and 3A, B). A drill stop can be used, or a malleable retractor is placed inferior to the coracoid process to ensure the drill bit does not plunge too deep below the coracoid process. It is important that the direction of the drill is in the center of the superior surface of the coracoid process to achieve an optimal fixation. FIGURE 2. Dislocated ACJ showing torn coracoclavicular ligaments. Volume 8, Issue 4 215

4 Lim et al FIGURE 3. A, Drilling through the 4 cortices of the clavicle and the coracoid process. B, Drilling through the 4 cortices of the clavicle and the coracoid process. Clamp is holding coracoclavicular interval reduced. The guide wire attached to the Tightrope is passed through the clavicle and retrieved from the undersurface of the clavicle (Figs. 4A, B). The passage of the leading oval button through the coracoid process can be done in 1 of 2 ways. The lead suture can be passed through the coracoid and retrieved below the coracoid. With traction applied on this suture, it will deliver the button through the coracoid process. However, the authors prefer to remove the leading suture and position the leading button in the coracoid hole. It can then be pushed through the hole with a small instrument such as a Watson Cheyne periosteal elevator. The position of the button should be confirmed with an image intensifier. When in place, the oval button should be perpendicular to the line of the suture and directly apposed to the undersurface of the coracoid process, whereas the round, superior button lies flat on the superior surface of the clavicle (Figs. 5A, B). Once the leading button is positioned, traction is placed on the 2 free ends of the sutures, which closes the interval between the 2 buttons and reduces the clavicle onto the coracoid process (Figs. 6A, B). Both ends of the suture are then alternately tightened until the superior button sits snugly on the clavicle. The author s aim was to reproduce the normal coracoclavicular interval and achieve anatomical reduction of ACJ. This should allow normal rotation of the clavicle on the Fibrewire sutures. It should therefore not be too tight. Once the position of the implant and reduction of ACJ are confirmed to be satisfactory on fluoroscopy, the sutures are tied. Tension on the sutures should be aimed at achieving and maintaining adequate reduction while allowing physiological motion. Subsequently, the conoid and trapezoid ligaments, superior part of the AC ligament, and trapezius-deltoid fascia are repaired. Lateral Clavicle Fracture This fixation technique can also be used in the presence of lateral clavicle fracture with increased coracoclavicular interval. Depending on the size of lateral fragment, it is either excised, or open reduction and internal fixation is performed using a plate. If the lateral fragment is excised, the distal clavicle and coracoclavicular interval are reduced and stabilized using the technique as described above. If the lateral fragment is of sufficient size to warrant fixation, then the fixation technique is slightly modified. After preparing the bony tunnels between clavicle FIGURE 4. A, Passing the oval button through the clavicle with the guide wire provided. B, Passing the oval button through the clavicle with the guide wire provided. 216 Techniques in Shoulder & Elbow Surgery

5 ACJ Reduction, Repair, and Reconstruction FIGURE 5. A, Pulling on the sutures will approximate the 2 buttons and reduce the coracoclavicular interval. B, Image intensifier picture confirms reduction of the AC parts and correct position of the oval and round buttons. and coracoid, the oval metallic button is passed through a hole in the plate before passing through the clavicle and coracoid. Internal fixation of the fracture is then performed, and adjunct fixation is achieved using the Tightrope. In such cases, the superior metallic button is positioned and secured over a hole in the clavicular plate. Chronic Cases In chronic cases, the authors recommend excision of the distal end of the clavicle and a double-bundle autograft reconstruction of the coracoclavicular ligament. The authors prefer to use the hamstring tendon as a graft. The role of adjunct fixation such as the Tightrope system is to provide initial fixation to help reduce and maintain reduction until the graft has ligamentized. It is important to mark out all the drill holes before excision of the clavicle. To achieve an anatomical reconstruction of both the trapezoid and conoid ligaments, the lateral most drill hole for the passage of the hamstring graft should be 23 mm (22 mm for women) 21 from the distal end of the clavicle. It should also be placed slightly anterior to the center on the superior surface of the clavicle. The medial drill hole should be placed 42 mm (37 mm for women) 21 from the distal end of the clavicle. The medial dill hole should be positioned posteriorly on the superior surface of the clavicle. There should be adequate bone bridges surrounding the drill holes. The 3.65-mm drill bit used for the passage of the Tightrope implant is positioned on the superior aspect of the clavicle such that it is between the 2 previously marked drill holes. The placement of the Tightrope implant is then carried out as alluded above. Using a sagittal saw, 1 cm of the distal end of the clavicle is then resected. The passage of the graft through the clavicle and under the coracoid process is aided by first passing an Ethibond no. 5 through the clavicle and under the coracoid process. One end of the suture is then tied to the hamstring graft by means of a whipstitch. The other free end of the suture is tied onto itself, thus creating a circular loop as shown in the FIGURE 6. AYB, Pulling on the sutures approximates the buttons and reduces the coracoclavicular interval. Volume 8, Issue 4 217

6 Lim et al FIGURE 7. A, The use of an ETHIBOND loop suture to aid in wheeling the graft through the clavicle and beneath the coracoid process. B, Distal end of clavicle resected and hamstring graft passed twice around the coracoclavicular interval. diagram (Figs. 7A, B). The Ethibond is then pulled from 1 end wheeling the graft through the passage. The graft is passed transosseously twice through the clavicle. It is first passed through the lateral drill hole on the clavicle in an inferior-superior direction and then through the medial drill hole from the superior-inferior direction through the clavicle. It is looped under the coracoid process deep to the oval button. Subsequently, the graft is brought through the clavicle in the same path as before such that the graft spans the coracoclavicular interval twice. (Fig. 7C) Once the graft is in a satisfactory position, the clavicle is reduced, and the Tightrope is then tied securely. The 2 ends of the graft are sutured to each other with no. 2 Fibrewire at the coracoclavicular interval. RESULTS AND COMPLICATION The senior author has used this fixation technique on 9 occasions in 8 patients. All patients were men with a mean age of 35 years (range, 23Y50 years). Of these 9 procedures, 1 was performed in a revision setting after failure of original fixation with Tightrope. This case is excluded from further analysis, which will focus on primary cases. In 8 cases, this fixation technique was used as a primary fixation. The dominant limb was involved in 6 of 8 cases. Indications of the procedure included a grade 5 ACJ dislocation (1 patient), grade 4 ACJ dislocation (1 patient), grade 3 ACJ dislocation (2 patients), and a lateral clavicle fracture with significantly increased coracoclavicular interval (4 patients). Of the 4 patients with clavicular fractures, 2 underwent open reduction and internal fixation using a plate in addition to Tightrope fixation. In the other 2 cases, the lateral end of the clavicle was excised. Of the 8 patients, 7 were operated upon within 4 weeks of their injury. In these acute cases, only Tightrope fixation was used to reduce the coracoclavicular interval. In the only chronic case, the patient had nonunion of distal clavicle fracture with increased coracoclavicular distance. He underwent distal clavicle excision, coracoclavicular ligament reconstruction using hamstring autograft, and Tightrope fixation. Intraoperative satisfactory reduction and fixation were confirmed clinically and with intraoperative fluoroscopy. Postoperatively, a sling was applied for 4 weeks with instructions of gentle range of motion up to shoulder level. Light duties were allowed from 4 to 12 weeks, and full duties resumed from 3 months onward. Contact sports were discouraged for 6 months. Clinical and radiological follow-up was at 2 weeks, 6 weeks, and 3 months. Minimum follow-up of 6 months is available for all the patients. Intraoperative and 2-week postoperative radiographs demonstrated excellent reduction of the coracoclavicular interval and the ACJ in all patients (Fig. 8). However, 6-week postoperative x-rays of 4 patients revealed a loss of reduction of the ACJ and an increased coracoclavicular interval (Fig. 9). All 4 patients had Tightrope fixation for acute injuries. Two of the patients FIGURE 8. Intraoperative fluoroscopic image shows anatomical reduction of ACJ and satisfactory placement of fixation device. 218 Techniques in Shoulder & Elbow Surgery

7 ACJ Reduction, Repair, and Reconstruction FIGURE 9. Six-week follow-up x-ray shows loss of reduction and increased coracoclavicular interval. FIGURE 11. This patient had Tightrope fixation for grade 3 ACJ dislocation. Three-month postoperative x-ray shows anatomical ACJ reduction and calcification in CCI. CCI indicates coracoclavicular interval. in which fixation failed underwent clavicle plating and Tightrope fixation for a distal clavicle fracture with increased coracoclavicular interval. The other 2 patients hadarockwoodgrade3and4dislocation respectively. All denied any further episodes of trauma. Of the 4 patients with fixation failure, 3 reported feeling a snap followed by prominence of the lateral clavicle; the fourth patient reported waking up in the morning with recurrence of the dislocation. All the failures occurred between 2- and 6-week follow up visits. Figure 9 illustrates an example of loss of reduction secondary to fixation failure (same patient as Fig. 8). Figure 10 demonstrates loss of fixation in another patient where Tightrope fixation was used with clavicle plating. Of the 4 patients with fixation failure, 2 underwent further surgery, 1 requiring removal of clavicle plate and Tightrope and the other patient requiring revision fixation with Tightrope in addition to autograft hamstring reconstruction of coracoclavicular ligament. The remaining 2 patients were treated nonoperatively. One of these patients has a very prominent lateral end of clavicle, with painful clicking at ACJ on manual work and extremes of abduction and flexion. However, he has refused further surgical intervention. The other patient is completely asymptomatic. At final follow-up, 4 of the 8 patients had uneventful recovery with no pain and resumption of full duties. Anatomical reduction of the ACJ was maintained. Minor calcification in coracoclavicular interval was seen on plain radiograph (Fig. 11). There were no iatrogenic coracoid or clavicle fractures. Overall, there was a 50% fixation failure rate when Tightrope fixation was used in primary procedures (excluding revision surgery). Retrieved specimen revealed multiple areas of abrasion on no. 5 Fibrewire suture (Fig. 12). The mechanism of failure is postulated to be secondary to suture abrasion. This could have resulted from abrasion on metallic buttons, clavicle plate, or sharp bony edges of coracoid or clavicle. Both patients who underwent clavicle plating in addition to the Tightrope fixation had failure of fixation. This accounted for 50% of the failures in this series. The abrasion of the suture can also potentially occur against the bone edges of the FIGURE 10. In this patient with distal clavicle fracture, Tightrope was used with clavicular plate fixation. Threemonth postoperative x-ray shows loss of reduction. FIGURE 12. Retrieved no. 5 Fibrewire suture. Volume 8, Issue 4 219

8 Lim et al clavicle and/or coracoid process if the drill holes are not in an exact straight line. Besides failure of fixation, there were no neurovascular or other complications in this series. There is a potential for late development of symptomatic osteoarthritis of ACJ, which may necessitate a delayed excision of distal clavicle. MAJOR CONCERNS The high failure rate in our series is a major concern of using the Tightrope system. It may represent our learning curve, but a structural flaw in the system cannot be ruled out at this point. There are, however, many attractive potential advantages of using the Tightrope system. The tensile strengths of the native coracoacromial ligaments and a single no. 5 Fibrewire are highly comparable, with reported values of about 500 N 22 and 483 N, 23 respectively. The pullout strength of a metallic button has beenshowntobeinexcessof1150n. 13 The use of 4 strands of no. 5 Fibrewire to hold 2 metallic buttons to close the coracoclavicular interval is, at least theoretically, a much stronger repair than the native ligaments, coracoclavicular slings, suture anchors, or coracoacromial ligament transfers. 22 Furthermore, it provides a nonrigid fixation of the ACJ, thus allowing normal rotation of the clavicle. This is an attractive advantage of this technique. In contrast, techniques using screws do not allow for this rotation, and screws usually work loose due to repetitive strains placed on the screw bone interval. The Tightrope metallic buttons protect the sutures from cutting through the clavicle, a failure mode often seen when using isolated sutures. The low profile of the implant may potentially also eliminates the need for a second operation for removal of the implant. The concept of this fixation technique is good and provides very strong intraoperative fixation in addition to other potential benefits as outlined above. Despite all these theoretical advantages, there was a very high rate of loss of reduction in our small series (4/8 patients). To the best of our knowledge, there are no published studies in the English literature on the efficacy of using Tightrope fixation in ACJ dislocations. Our retrieved specimen (Fig. 12) suggests that the mode of failure is likely to be secondary to suture abrasion. This could have resulted from abrasion on metallic buttons, clavicle plate, or sharp bony edges of coracoid or clavicle. Other potential causes such as knot slippage 24 cannot be excluded in the 2 other patients that did not receive further surgical treatment. The metallic button fixation may have promise as an alternative for stabilization of dislocated ACJ. However, further biomechanical analysis of this fixation device is required to evaluate and address the potential cause of its in vivo failure. REFERENCES 1. Phillips AM, Smart C, Groom AFG. Acromioclavicular dislocation: conservative or surgical therapy. Clin Orthop Relat Res. 1998;353:10Y Boswoth BM. Acromioclavicular separations: new method of repair. Surg Gynecol Obstet. 1941;73:866Y Larsen E, Petersen V. Operative treatment of chronic acromioclavicular dislocation. Injury. 1987;18(1):55Y Weaver JK, Dunn HK. Treatment of acromioclavicular injuries, especially complete acromioclavicular separation. J Bone Joint Surg Am. 1972;54(6):1187Y Urist MR. Complete dislocation of the acromioclavicular joint. J Bone Joint Surg. 1963;45A:1750Y Mumford EB. Acromioclavicular dislocation. J Bone Joint Surg. 1941;23:799Y Berson BL, Gilbert MS, Green S. Acromioclavicular dislocations: treatment by transfer of the conjoined tendon and distal end of the coracoid process to the clavicle. 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9 ACJ Reduction, Repair, and Reconstruction 18. Schlegel TF, Burks RT, Marcus RL. A prospective evaluation of untreated acute grade III acromioclavicular separations. Am J Sports Med. 2001;29(6):699Y Press J, Zuckerman JD, Gallagher M, et al. Treatment of grade III acromioclavicular separations. Operative versus nonoperative management. Bull Hosp Jt Dis. 1997;56(2): 77Y Zanca P. Shoulder pain: involvement of the acromioclavicular joint. (Analysis of 1,000 cases). Am J Roentgenol Radium Ther Nucl Med. 1971;112(3):493Y Renfree KJ, Riley MK, Wheeler D, et al. Ligamentous anatomy of the clavicle. J Shoulder Elbow Surg. 2003;12: 355Y Harris RI, Wallace AL, Harper GD, et al. Structural properties of the intact and the reconstructed coracoclavicular ligament complex. Am J Sports Med. 2000;28(1):103Y Barber FA, Herbert MA, Richards DP. Sutures and suture anchors: Update Arthroscopy. 2003;19(9):985Y Abbi G, Espinoza L, Odell T, et al. Evaluation of 5 knots and 2 suture materials for arthroscopic rotator cuff repair: very strong sutures can still slip. Arthroscopy. 2006; 22(1):38Y43. Volume 8, Issue 4 221