Open management of atraumatic and traumatic disorders of the acromioclavicular joint: Indications, techniques, and outcomes





Surgical indications: Atraumatic disorders


Distal clavicle osteolysis and osteoarthritis


Distal clavicle osteolysis is an atraumatic condition that can result in significant pain and discomfort. Excision of the lateral portion of the clavicle is indicated when the cause of shoulder pain can be attributed solely to the acromioclavicular (AC) joint or a component of a shoulder pain–generating syndrome. In 1941, Gurd and Mumford independently published the first accounts of the procedure. , Subsequently, it has been the subject of many investigations seeking to define the essential yet “safe” extent of excision by both open and arthroscopic approaches while protecting the investing ligamentous support of the AC joint and the coracoclavicular (CC) ligaments. By doing so, postresection instability that might contribute to discomfort and dysfunction is potentially minimized.


Surgical techniques: General


Historically, the recommended resection length has varied from 0.5 to 2.5 cm, although the precise amount to resect is unknown. Based on cadaveric studies, 5 mm is suggested to adequately prevent bony abutment in both rotationally and axially loaded shoulders if the CC and AC ligaments are intact. This recommendation was confirmed in an arthroscopic cadaveric study demonstrating that, if the resection was 2.5 mm or less, abutment was likely to occur between the acromion and the clavicle, particularly inferiorly and posteriorly, and that joint stiffness diminished with the amount of bone resected. Furthermore, a resection of greater than 0.8 cm in women and 1.0 cm in men may result in detachment of some portion of the trapezoid ligament. A resection of less than 11.0 mm may not violate any portion of the trapezoid ligament in 98% of men or women, and resection of less than 24.0 mm should not violate the conoid ligament. To prevent the abutment of the acromion and clavicle during adduction of the arm, Neer advocated the removal of 1.5 to 2.0 cm, resecting more superiorly and posteriorly than inferiorly and anteriorly.


When performing AC joint resection, symmetric resection of both the medial acromion and lateral clavicle is recommended as anterior-to-posterior peak load to failure is significantly higher compared with distal clavicle excision (DCE) alone. However, when biomechanically examining horizontal translations of the clavicle after DCE, progressively increased anterior-to-posterior excursions are noted compared with the native joint with inferior capsule excision and 10-mm bone excisions, even when the superior and posterior AC capsular ligaments and the CC ligaments remained intact. Furthermore, with open techniques for DCE, meticulous closure of the superior capsule and investing AC ligaments is extremely important. However, when performing lateral clavicle excision, it must be noted that persistent pain can occur due to inadequate resection or when performed for the wrong indication.


Open distal clavicle excision


In the orthopedic literature, there are multiple publications of the results of open DCE. In a 2010 systematic review, Pensak et al. recognized excellent and good results in 79% of the cases. The clinical benefit associated with performing an additional acromioplasty at the time of the DCE seems insignificant. In the presence of heavy physical labor or worker’s compensation or litigation, the results might not be as predictable. , , Alford and Bach noted savings of operative time with open DCE compared with arthroscopic techniques; however, this remains highly controversial.


Procedure


The patient is placed in the beach chair position with the head supported on an adjustable well-padded headrest to allow free access to the superior aspect of the shoulder. The skin incision is made in the relaxed skin tension lines approximately 1 cm medial to the AC joint, extending for 3 to 4 cm ( Fig. 22.1 ). A small, straight Gelpi retractor is placed into the subcutaneous tissue, which is gently elevated from the underlying fascia.




Fig. 22.1


A superior incision in the relaxed skin tension lines is made slightly medial to the acromioclavicular joint for a distance of 3 to 4 cm.

(Courtesy Steven B. Lippitt, MD.)


Beginning 2.0 to 2.5 cm medial to the AC joint, electrocautery is used to incise the soft tissue overlying the superior aspect of the clavicle ( Fig. 22.2 ). The incision should be carefully placed to avoid the trapezius and deltoid muscles from their respective insertions. The incision is continued laterally through the capsule of the AC joint onto the acromion process for a distance of approximately 0.5 to 1 cm. Subperiosteal dissection of the distal clavicle is carried out with electrocautery to create anterior and posterior soft tissue flaps that include the capsule, the superior ligaments of the AC joint, and the adjacent muscles. Complete soft tissue dissection is confirmed with a 0.25-inch key elevator enabling the placement of two small Chandler retractors bent to 90 degrees anterior and posterior to the distal clavicle. The arm is then moved into adduction to avoid any abutment. With the help of a mobile C-arm (fluoroscopy), a length of 5 to 8 mm of the distal clavicle is measured, marked, and resected using a microsagittal saw ( Fig. 22.3 ). The resected fragment is grasped with a towel clip or pointed bone reduction forceps and manipulated to allow access for the release of the remaining soft tissue attachments inferiorly.




Fig. 22.2


In line with the clavicle, the deltotrapezius fascia and underlying acromioclavicular joint capsule are divided and reflected from the distal clavicle.

(Courtesy Steven B. Lippitt, MD.)



Fig. 22.3


The surrounding soft tissues are protected as the lateral clavicle is excised with a microsagittal saw.

(Courtesy Steven B. Lippitt, MD.)


Upon removal of the resected lateral clavicle, the wound is thoroughly irrigated with normal saline. The resected clavicular surface is inspected, palpated, and smoothed, if needed, using a pinecone bur, rasp, or file. Proliferative synovium and abnormal intra-articular disk material are excised. By placing a fingertip into the area of resection and performing extremity adduction, contact between the acromion and the residual distal clavicle is recognized and corrected by additional resection.


The surrounding soft tissues are infiltrated with a local anesthetic solution consisting of equal parts of 0.5% Marcaine with epinephrine and 1% lidocaine. With the medial subcutaneous flap retracted with a bent Army-Navy retractor, a 6-D Mayo trocar needle delivers No. 2 nonabsorbable sutures through the anterior and posterior soft tissue flaps ( Fig. 22.4 ). No more than three sutures placed with a figure-of-eight technique are usually necessary. The sutures are tied with four rows to limit the likelihood of palpable and potentially painful knots beneath the skin at the surgical site. For extremely thin patients, absorbable sutures are preferred. The subcutaneous tissue is closed with 2-0 absorbable sutures using a buried technique, capturing the dermal layer to ensure excellent superficial soft tissue apposition. Strips of 0.5-inch adhesive-backed paper tape cut in half are applied to the skin. A sterile dressing covers the wound, and the arm is placed in a sling.




Fig. 22.4


The residual defect is closed by careful repair of the deltotrapezius fascia and acromioclavicular joint capsule. No more than three sutures placed with a figure-of-eight technique are usually necessary. The sutures are tied with four throws to limit the likelihood of palpable and potentially painful knots beneath the skin at the surgical site. Leaving a small tag further reduces the possibility of palpable suture.

(Courtesy Steven B. Lippitt, MD.)


Postoperative rehabilitation


Patients are discouraged from active arm elevation without the assistance of the opposite limb for 3 to 4 weeks to protect the deep soft tissue repair. Heavy use of the extremity is not recommended for 6 to 8 weeks to ensure that sufficient preliminary healing of the AC ligaments has taken place and that the residual void created at the time of DCE has been filled with scar. Hydrotherapy to obtain range of motion is suitable as soon as the wound has healed. Return of full strength, range of motion, and full function can be expected in most cases by 12 weeks.


Technical pearls and pitfalls


Cosmetically unappealing scars may be avoided by carefully placing the incision in the relaxed skin tension lines. Placing the skin incision approximately 1 cm medial to the palpable prominence of the distal clavicle enables optimum and safe placement of the saw. The angle of resection favors removing slightly more bone superiorly and posteriorly than inferiorly and anteriorly ( Fig. 22.5 A). This orientation of the plane of resection prevents contact between the remaining clavicle and the acromion when the arm is placed in cross-body adduction (see Fig. 22.5 B). In addition, it may be important to smooth the lateral corner of the clavicle, especially in patients with prominent bony structures. A saw is preferred to the use of either a bur, which creates more bone debris, or an osteotome, which can shatter the bone.




Fig. 22.5


(A), The plane of resection favors slightly more bone removal superiorly and posteriorly to prevent abutment of the acromion process on the clavicle during extremity adduction. (B) A proposed mechanism for painful instability after distal clavicle excision is abutment of the remaining posterolateral clavicle against the posteromedial acromion

(Courtesy Steven B. Lippitt, MD.)


The soft tissue sleeve that includes the AC joint capsule and its supporting ligaments is carefully closed side to side without an attempt to obliterate the dead space formed by the absence of the lateral clavicle. It is important that the repair suture engage the entirety of the reflected soft tissue, not just its most superior/superficial portion. This effectively repairs the superior AC ligaments and capsule, which reduces the possibility of iatrogenic AC joint instability. In patients with joint laxity, open DCE should be preferred over an arthroscopic-assisted technique, to avoid horizontal or rotational instability. The temptation to create an interposition arthroplasty using the soft tissues adjacent to the joint should be resisted. Their relative immobility risks a closure under tension that can lead to dehiscence of the tissues at the repair site. Overtightening the trapezius or deltoid muscle at the resection site can contribute to focal discomfort. Likewise, an insufficient closure can be painful, cosmetically unappealing, and functionally compromising.


Heterotopic ossification (HO) can develop at the surgical site. Preventive measures include (1) subperiosteal dissection with electrocautery rather than sharp or blunt elevation of the soft tissue from the bone, (2) thorough irrigation of the surgical site to remove residual bone debris, and (3) prophylactic administration of pharmacologic agents such as indomethacin.


Outcomes and complications


DCE, regardless of method, following trauma to the AC joint produces fewer excellent and good results than when it is performed for nontraumatic conditions. , , , Cheung et al. reported expectedly improved clinical outcomes at a mean follow-up of 8.3 years. Eskola found that patients with a resection of more than 1.0 cm have more pain than patients with less than 1 cm of resection.


According to a systematic review performed in 2007, there is little argument that excision of the lateral clavicle successfully addresses the majority of the pathologic entities encountered at the AC joint. However, there are unsatisfactory outcomes because of cosmesis, pain, and dysfunction that are typically mechanical in nature. The factors are often interrelated and include improper surgical technique and resection, instability, loss of soft tissue integrity, HO, scars, and neuromas. Failure to resect enough distal clavicle can result in continued, symptomatic abutment of the acromion and the clavicle (see Fig. 22.5 ). The problem is usually secondary to inadequate visualization or underestimation of the amount of resection when DCE is performed arthroscopically.


Overresection, which is most often accompanied by manifestations of instability, is a far more challenging problem, nearly always resulting in more significant pain and dysfunction than underresection. Different degrees of overresection and extent and directions of instability are possible. Exceedingly generous resections, usually radiographically apparent, place the important CC ligaments at risk, especially the most lateral trapezoid. Refractory symptoms usually necessitate a formal reconstructive stabilizing procedure to specifically address the instability pattern. The more subtle but nevertheless disabling symptoms are probably attributable to translational microinstability in the anteroposterior plane.


Several studies have compared the results of arthroscopic and open excision of the lateral clavicle with confirmation of the benefits of each method. , In a 2007 systematic review, Rabalais and McCarty demonstrated that arthroscopic distal clavicle resection provided better results than the open procedure, but this observation is mostly comprised of low-level evidence. Flatow et al. reported earlier recovery of comfort with an arthroscopic method. Using validated outcome measurement tools, Freedman et al. failed to demonstrate significant differences 1 year postoperatively between arthroscopic and open procedures, with the exception of significant improvements in visual analog scale (VAS) scores in the arthroscopic group but not the open group. With the arthroscopic method, there is opportunity to diagnose and treat intra-articular lesions that would otherwise go undetected with open methods. Elhassan’s group revealed comparable results in both arthroscopic and open groups, although 90% of the arthroscopic group underwent subacromial decompression as well as many other additional procedures compared with the open group. Patient dissatisfaction, regrowth of the distal clavicle, and revision surgery were more frequent in the arthroscopic group, although pain directly over the AC joint was less frequent. In another comparative study, the only difference between open and arthroscopic DCE at the 4- to 5-year follow-up was less residual pain in the arthroscopic group.


Complication rates after DCE are noted to be high, with up to 64% of the cases being reported. Residual tenderness of the AC joint (55%), incisional scar sensitivity (55%), postoperative stiffness (29%), hypertrophic incisional scar (14%), and infections (10%) are among the most common reported complications. , Motion limitation after an appropriate period of healing is occasionally reported, with undetected stiffness existing at the time of the index procedure likely being the most common precipitating factor. , , HO and calcification can occur after an AC joint injury or following excision of the lateral clavicle. , , , , Symptomatic HO or calcification is quite uncommon, although it may be an offending lesion when the outcome of DCE by either open or arthroscopic methods is not considered satisfactory ( Fig. 22.6 ). , , Patients at high risk for developing HO, such as those with a previous history of the lesion or patients with either hypertrophic pulmonary osteoarthropathy, diabetes mellitus, or spondylitic arthropathy, may be candidates for pharmacologic prophylaxis. The formation of mechanically significant heterotopic bone at the site of DCE is rare. Miscellaneous conditions reported to confound the results of DCE include preexisting psychiatric illness, suprascapular neuropathy, infection, and osseous bridging of the AC joint. , , ,




Fig. 22.6


An extreme example of heterotopic ossification with nearly complete restoration of the lateral clavicle following open excision.


Other atraumatic indications


An open approach to the AC joint may be needed in the event of septic arthritis, painful cysts, or local or metastatic disease including primary bone tumors such as multiple myeloma. Open techniques are rarely indicated for crystalline arthropathy.


Surgical indications: Traumatic disorders


Overview


The current literature covers a variety of operative treatment options for AC joint dislocations, a few of which have been reinvented and some even abandoned secondary to high complication rates or unsatisfactory results, with surgeons and researchers continuing to search for the most reliable method of joint stabilization ( Table 22.1 ). A broad consensus exists that high-grade AC joint instability (ACJI) (type IV to VI according to the Rockwood classification ) should be treated surgically, with low-grade injuries (type I to II) requiring a conservative treatment algorithm. However, to date there remains significant controversy on how best to treat type IIIA and type IIIB injuries, making these patients a challenging cohort for shoulder surgeons (see Chapter 21 ). Subsequently, the ever-growing body of literature has been exhaustively perused by several authors, from which have emerged current concepts reviews, systematic reviews, and meta-analyses attempting to reveal the best evidence for the treatment of all AC joint dislocations. , ,



TABLE 22.1

Modified Rockwood Classification According to the ISAKOS Upper Extremity Committee Consensus Statement

From Borbas P, Churchill J, Ek ET. Surgical management of chronic high-grade acromioclavicular joint dislocations: a systematic review. J Shoulder Elbow Surg . 2019;28(10):2031–2038.




























































Type AC Ligaments CC Ligaments Deltotrapezial Fascia CC Interval on Radiograph Notes
I Sprained Intact Intact Normal
II Disrupted Sprained Intact <50% Vertical subluxation of the distal clavicle
IIIA Disrupted Disrupted Disrupted 50–100% Stable AC joint without overriding of the clavicle and without significant scapular dysfunction
IIIB Disrupted Disrupted Disrupted 50–100% Overriding clavicle and therapy-resistant scapular dysfunction
IV Disrupted Disrupted Disrupted Increased Clavicle posteriorly displaced (horizontal instability)
V Disrupted Disrupted Disrupted 100–300%
VI Disrupted Disrupted Disrupted Decreased Clavicle displaced inferior to coracoid

AC, Acromioclavicular; CC, coracoclavicular; ISAKOS, International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine.


Currently, evidence is lacking that special groups of patients mandate consideration for operative treatment. It has been suggested that operative treatment be reserved for heavy physical laborers, younger patients, overhead athletes, and frequent overhead users. , , , However, on the contrary, there appears to be little to no evidence to support the claim that the outcome of operative treatment is better than that of nonoperative treatment. ,


Operative techniques can be broadly classified into those that repair or reconstruct the AC joint (anatomic or nonanatomic) versus AC joint excision, with excision viewed as a salvage procedure for cases of failed repair or reconstruction.


Nonoperative versus operative treatment: General considerations


When compared with nonoperative treatment, operative treatment can result in less pain and better endurance, especially during overhead work. Operative treatment has resulted in improved pain and patient satisfaction in both short- and long-term follow-up studies. , , In contrast, no differences between operative and nonoperative treatment have been observed in shoulder strength, pain relief, throwing ability, or osteoarthritis (OA) according to a 2011 meta-analysis from Smith et al.; however, better cosmesis and increased time lost from work occurred with operative treatment. In another systematic review in 2014, Korsten et al. recognized that both subjective and objective outcomes were better with operative treatment, although radiographic abnormalities were more common. Although subjective and radiographic outcomes were better with operative treatment, objective parameters (University of California at Los Angeles [UCLA] score, Constant-Murley [C-M] score, American Shoulder and Elbow Surgeons [ASES] score, ACJI scores) were not significantly different. In high-performance overhead athletes, complete pain relief and return to “normal” was achieved more predictably with operative treatment (92% vs. 80%). Return to professional football required nearly 60 days following those that underwent surgical management for high-grade injuries. Cardone et al. reported a trend toward earlier return to football (i.e., Australian rules) with a more satisfactory outcome following operative treatment.


Open reconstructive treatment for acute or chronic acromioclavicular joint injuries


Historical perspective


A plethora of literature has been published describing surgical techniques to reconstruct the AC joint. Historically, Sage and Salvatore reported primary AC ligament repair with internal fixation or CC reinforcement more than 50 years ago. Even recently, direct ligament repair backed up with a temporary CC screw has been described ( Fig. 22.7 ). Rushton et al. stabilized the AC joint via two pairs of transosseous tunnels between the acromion and distal clavicle and biologic tendon augmentation. Sandmann et al. reported a triple cerclage technique whereby one AC and two CC sutures maintained joint reduction. Sobhy used a single nylon tape around the coracoid, through the clavicle, and across the AC joint.




Fig. 22.7


Acromioclavicular, trapezoid, and conoid ligament suture repair protected with a coracoclavicular screw.

(Modified from Assaghir YM. Outcome of exact anatomic repair and coracoclavicular cortical lag screw in acute acromioclavicular dislocations. J Trauma . 2011;71[3]:E50–E54.)


The AC joint may be reduced by closed or open techniques and stabilized with metallic wires or pins that temporarily cross the joint. , , , The importance of supplemental techniques performed in conjunction with internal fixation has been emphasized by some authors. These techniques include additional repair of the AC and CC ligaments, AC and CC ligament repair reinforcement with the intra-articular disk, repair or imbrication of the deltoid and trapezius attachments, adjacent soft tissue transfers (coracoacromial ligament [CAL], short head of the biceps tendon), DCE, autologous fascia lata suspension, CC suture augmentation, and clavicle osteotomy. *


* References , , , , , , , , , , , , , .

The duration of temporary fixation is typically longer than 6 weeks but varies by technique. Motion restrictions are mandatory to protect the integrity of the pins or wires until their removal. Thereafter, motion and strengthening programs are introduced. Of note, the use of smooth wires for fixation of the AC joint (either temporary or permanent) has been largely abandoned due to the risk of wire migration and loss of joint reduction (see Chapter 24 ).


Coracoacromial ligament and tendon transfer


Transposing the CAL into the resected distal clavicle was first suggested in 1917 by Cadenet, then advocated by Neviaser in the early 1950s, and finally modified by Weaver and Dunn in 1972, who used the technique for both acute and chronic type III injuries. , , , Other authors have used the CAL in the same or a similar manner , , , or have modified the previously described Weaver-Dunn method. , The CAL, with or without an accompanying fragment of bone, may be transferred to the clavicle with or without supplementary fixation. Augmentation of the CC ligaments in conjunction with the Weaver-Dunn operation have been supported by the results of experimental studies. In 2014, Cerciello et al. described a modified Cadenet procedure with an additional CC cerclage, CC ligament remnant suturing, and transarticular dual K-wire fixation of the reduced AC joint.


Another method for incorporating the CAL was originally described by Vukov. It differs in that the ligament is left intact, and the reduced distal clavicle, having undergone a limited distal resection, is “elastically” affixed with sutures passed through transosseous tunnels in the clavicle.


In 1965, muscle transfers were first suggested as a reasonable treatment for type III injuries. , The tip of the coracoid process, including the coracobrachialis and the short head of the biceps tendon, was osteotomized and attached to the clavicle. Scattered reports appeared later, some with slight modifications of the technique. , Transposition of the long head of the biceps or a slip of the conjoined tendon have been described as substitution methods for the CC ligaments. Jiang et al. additionally described a reconstruction technique with a proximally based conjoined tendon transfer supplemented with transclavicular sutures anchored in the coracoid process. ,


Biomechanical investigations


Biomechanically, the CAL transposition as used in the Weaver-Dunn reconstruction is significantly weaker and more lax compared with intact CC ligaments, CC screw fixation, and synthetic devices. , The Weaver-Dunn procedure, even with modifications, fails to reproduce the load-to-failure durability of the intact AC and CC ligament complex. ,


In contrast, Shu et al. documented the effectiveness of a novel reverse CAL transfer when compared with isolated CC ligament reconstruction. In addition, LaPrade et al. recognized that when the Weaver-Dunn reconstruction is combined with coracoid transclavicular cerclage, motion at the AC joint is restored to near-normal values. In their comparative study, Lee et al. had similar conclusions but also documented the superiority of the transclavicular coracoid cerclage that used a semitendinosus tendon graft. From their investigation, Luis et al. concluded that for sufficient resistance to undesirable AC joint motion, the Weaver-Dunn reconstruction should always be accompanied by supplemental stabilization methods. A similar conclusion was reached by Wellman et al., who used only the medial one-half of the CAL together with polyester cord secured with flip buttons. Several biomechanical studies have identified the inferior biomechanical properties of the Weaver-Dunn reconstruction when compared with alternate, more “anatomic” or alternative reconstructions. Moreover, the stabilizing advantages of additional CC ligament reconstruction at the time of the Weaver-Dunn method have been shown. ,


Biomechanically, using portions of the conjoined tendon for CC ligament reconstruction have also been investigated. Sloan et al. demonstrated that the strength of the lateral half of the conjoined tendon (265 N) was nearly that of the CAL (246 N) in a simulated reconstruction, although it lacked the strength of the intact CC ligaments (621 N). They cited potential advantages of this technique, including retention of the CAL integrity and significantly longer autologous graft material. The pectoralis minor tendon morphology and tensile strength can also offer similar structural properties to the CAL. Although it has yet to be clinically evaluated, the use of the pectoralis minor tendon could circumvent the potential complications that may arise from the sacrifice of a normal and functionally important part of the coracoacromial arch.


Surgical outcomes and complications


Favorable results were reported by Weaver and Dunn and subsequently by other authors who performed the operation as originally described. , , , Modified Weaver-Dunn operations have also produced favorable outcomes. , , With a modification of the Cadenet method, Cerciello et al. reported a mean C-M score of 94.3, VAS pain score of 0.91, 92% satisfaction, complete reduction in 88%, and no degenerative changes. In a 2008 systematic review, Sood et al. concluded that (1) there was only low-level evidence to support the use of CAL transfer, (2) supplemental fixation did not improve surgical results, (3) acute and chronic cases fared equally when using this surgical technique, and (4) the outcomes with retention or excision of the distal clavicle did not differ unless the retained clavicle manifested OA, in which case the results were inferior. Comparing the Vukov and Phemister methods, Radovanovic et al. found similar outcomes but a shorter recovery time with the technique of Vukov.


Mixed results have been reported for the treatment of type III injuries with transposition of the tip of the coracoid process. , , , Skjeldal et al. advised that the procedure should not be performed in patients with acute type III injuries. Jiang et al. reported superior clinical scores and an overall excellent or good result in 89% of the patients when using the proximally based conjoined tendon and CC sutures; the majority of patients returned to the same level of work and sport.


Bosworth screw


In 1941, Bosworth was the first to describe the use of a screw between the clavicle and the coracoid process to achieve AC joint stability. Since then, several authors have modified the technique to treat AC joint separations ( Fig. 22.8 ). , , , Garrigues et al. described an intraoperative fluoroscopically aided method for the proper identification of the base of the coracoid process to facilitate the placement and security of purchase of a percutaneously placed CC fixation device. This method is applicable to more recent CC devices that incorporate cortical suture buttons (described later).




Fig. 22.8


Excellent reduction with restoration of a normal coracoclavicular interval with a coracoclavicular screw. (A) Anteroposterior stress radiograph of the right shoulder in a patient with a type III acromioclavicular dislocation. (B) A stress film of the left shoulder revealed it to be normal. (C) Postoperative radiograph showing the acromioclavicular joint reduced and held temporarily in place with a special modified coracoclavicular lag screw.

(From Rockwood CA, Green DP, eds. Fractures . 2nd ed. Philadelphia: JB Lippincott; 1984.)


When using the Bosworth procedure, the exploration and debridement of the AC joint has been advocated, , , , but some authors do not consider this an essential component of treatment. , , In the setting of CC stabilization, the necessity for the direct repair of the CC ligaments remains uncertain. , , , , However, some authors have emphasized the importance of supplemental CC ligament repair at the time of CC stabilization. Repair of the trapezius and deltoid fascial attachments can contribute to the overall strength of the repair and has been emphasized by several authors. , , , ,


There are significant variations in the recommendations for postoperative immobilization, restrictions, rehabilitation, the necessity for implant removal, and the timing of implant removal. , , , ,


Biomechanical investigations


Thirty years ago, upon comparing techniques for AC joint fixation, Kiefer et al. found that the most rigid fixation was provided by the Bosworth screw. Restoration of AC joint congruency using seven different methods of fixation between the clavicle and the coracoid were studied by Jerosch et al. They demonstrated satisfactory vertical stability with all of the techniques. Excessive horizontal translations between the acromion and the clavicle were demonstrated with all of the loop techniques and the Weaver-Dunn reconstruction, whereas the joint anatomy was best restored with the Bosworth screw or bone anchor reconstruction. Harris et al. revealed that Bosworth screw placement with bicortical purchase provided strength and stiffness as good as or better than the intact CC ligaments. In a cadaver model comparing the biomechanical function of different surgical procedures for AC joint dislocations, the Bosworth screw resulted in decreased primary and coupled translations and showed increased stiffness. CC sling and CAL transfer resulted in increased primary and coupled translations. In situ forces increased for all three reconstructions.


Additional experimental screw fixation methods for CC ligament reconstruction has been investigated. CC fixation comparing stainless steel and bioabsorbable 4.5 mm screws showed no difference in pullout strength and fixation strength that exceeded the intact CC ligaments. In a study by Motamedi et al., CC fixation with one cortex purchased was significantly weaker than the intact CC ligaments.


In a cadaver model, McConnell et al. performed reconstructions with CC loop (No. 5 polyester fiber [Mersilene]), CC screw, and hook plate fixation, and subjected the specimens to stiffness and failure testing. Hook plates reproduced physiologic stiffness more closely. The CC failed at the highest load and was the stiffest reconstruction, and the CC loop was the least stiff.


In a comparative investigation, Fialka et al. identified the poor mechanical properties of the Bosworth technique, especially at more than 90 degrees of abduction. Although transarticular K-wires were rigid and stable, a high rate of migration was observed. Of the techniques studied by Fialka et al., the most favorable construct from a mechanical standpoint was with the ligament augmentation and reconstruction system (LARS) device.


Surgical outcomes and complications


The outcome of the use of CC screws is generally excellent and good in more than 77% of patients, , , , , , , , even when ossification is forming between the clavicle and coracoid. , However, hardware failure, screw pullouts, and fractures, especially at the distal clavicle, may be noted as a significant limitation of CC screws. In 2010, Esenyel et al. highlighted a mean C-M score of 98, excellent results in 86.7%, and normal alignment in 96.7%. Percutaneous screw insertion is technically more challenging, thus resulting in a distinct complication profile.


Acromioclavicular joint reconstruction with hook plates


The first account of the use of a hook plate was published by Balser et al. almost 40 years ago. The principles of the hook plate are based on open reduction and internal fixation with a precontoured hook plate affording rigid internal fixation and sparing the articular surfaces of the joint ( Fig. 22.9 A and B). , , The device has the advantage of simultaneously stabilizing the CC (superior-inferior) and the AC (anterior-posterior) ligaments. With no other means of fixation augmentation, stability is afforded by scar that accompanies healing of the surrounding soft tissues. Several authors have described the use of supplemental fixation, including CC fixation with polydioxanone sulfate (PDS) sutures, direct CC ligament repair, suturing the capsuloligamentous sleeve of the AC joint, additional screw fixation through the plate, and transposition of the CAL as per Weaver and Dunn. , , , , Some authors have advised early range of motion within a day of the operation. , , , , Others limit motion after a brief period of protection. , , , , Implant removal is reported between 4 and 24 weeks; infrequently, the duration of implant retention is as long as 7 to 13 months. , Some authors do not routinely remove the device, , , whereas asymptomatic patients may occasionally refuse a secondary operation to remove the plate. Immediately after plate removal, vigorous efforts toward motion and strength recovery are initiated.




Fig. 22.9


(A) Acroplate (aap Implantate AG). (B) Hook plate for type III injury enabling excellent restoration of anatomy.

(A, From Cîrstoiu C, Rădulescu R, Popescu D, et al. Acroplate—a modern solution for the treatment of acromioclavicular joint dislocation. J Med Life . 2009;2[2]: 173–175.)


In the past decade, different hook plate designs have been presented. Although the appearance of the plates may vary, the principles since inception of the concept have not changed. Liu et al. designed and used the articulated micromovable and anatomic AC plate ( Fig. 22.10 ), and Ryhanen et al. described the use of a CC nitinol C-shaped hook implant (tifix AC-Hakenplatte; Fig. 22.11 ). Moreover, arthroscopic-assisted insertions have been described.




Fig. 22.10


Articulated hook plate applied across the acromioclavicular joint to permit some joint motion.

(From Liu Q, Miao J, Lin B, et al. Clinical effect of acute complete acromioclavicular joint dislocation treated with micromovable and anatomic acromioclavicular plate. Int J Med Sci . 2012;9[8]:725–729.)



Fig. 22.11


Tifix AC-hakenplatte.


(From Kienast B, Thietje R, Queitsch C, et al. Mid-term results after operative treatment of Rockwood grade III-V acromioclavicular joint dislocations with an AC-hook-plate. Eur J Med Res . 2011;16[2]:52–56.)


Biomechanical investigations


In an in vitro model of the AC joint, Nüchtern et al. not only demonstrated the physiologic stiffness of the hook plate but also the relevant role of the AC joint ligaments for restoring physiologic properties about the AC joint at the time of reconstruction. Kim et al. investigated changes in three-dimensional motion taking place at the AC joint with and without the presence of a hook plate. In patients who had undergone hook plate fixation for a distal clavicle fracture, they demonstrated diminished internal rotation (mean, 16 degrees) and increased anterior translation (2 mm) of the clavicle with respect to the medial acromion compared with the nonoperative side.


Surgical outcomes and complications


Hook plates have been used extensively in Europe, resulting in reports from various centers as far back as 33 years. *


* References , , , , , , , , .

In the earliest reports, the follow-up periods were limited to short-term follow-up with mixed and inconsistent outcomes.

References , , , , , , , , , , , , , .

Since then, the clinical and radiographic reliability of the method has been verified in multiple studies, and its use has become more widespread

References , , , , , , , , .

with consistently high mean C-M scores (>92) being reported. , , , , , , Kienast et al. reported good clinical outcomes in 84% of the cases after a mean follow-up of 36 months. According to these authors, both the AC and CC ligaments were appropriately reduced; however, minor joint asymmetry may exist at the completion of treatment, , with poor correlations between clinical and radiographic results being common. , , , , Di Francesco et al. used postoperative MRI to assess scarring/healing of the CC ligaments and found healing in 88% of patients. In addition, clinical scores are lower in the presence of persistent anterior-posterior instability , ; however, early return to work and sports remain common. , , , , ,


When comparing the hook plate and nonoperative treatment, Gstettner et al. found better clinical and radiographic results for patients treated with a hook plate. Furthermore, Ejam et al. observed no significant differences in clinical outcomes when comparing acute or delayed treatment. Recent reports from Asia highlighting the success of the hook plate have emerged in the orthopedic literature. , , , Chen et al. reported no loss of reduction and improved clinical outcomes after plate removal with a mean C-M score of 89. Dou and Ren reported 100% excellent and good clinical outcomes; however, this study was limited to a short-term follow-up. Using the micromovable and anatomic AC plate, Liu et al. reported a mean C-M score of 94, yielding excellent and good results in 94% and anatomic reductions in 88% of patients. In a 2017 multicenter randomized clinical trial comparing nonoperative and operative treatment of acute, complete AC joint dislocations (i.e., types III, IV, and V) using a hook plate, Mah et al. found no difference in general health status between treatment groups. This study has therefore questioned the efficacy of hook plate stabilization in the setting of acute, high-grade ACJI.


Suture augmentation and synthetic devices


The extraosseous, intraosseous, and transosseous placement of absorbable sutures, nonabsorbable sutures, wires, cables, anchors, and synthetic ligaments have been used for indirect AC joint stabilization ( Fig. 22.12 ). *


* References , , , , , , , , , , .

If the material is passed through drill holes in the clavicle, the coracoid, or both, the reduction is potentially more accurate and the outcome may be improved ( Fig. 22.13 ).

References , , , , , , , , , , .




Fig. 22.12


Acute type III injury. (A) Preoperative. (B) Final postoperative treatment using encircling permanent sutures with distal clavicle resection.



Fig. 22.13


Method of coracoclavicular reconstruction with loops passing through a prepared hole in the clavicle.

(Modified from Dimakopoulos P, Panagopoulos A. Functional coracoclavicular stabilization for acute acromioclavicular joint disruption. Orthopedics. 2007;30[2]:103–108.)


Various types of synthetic ligaments have been used for AC joint reconstruction, , , with the first reconstruction techniques using CC sutures dating back to 1996. Such methods theoretically pose less risk to adjacent neurovascular structures, have comparable strength of the native ligaments, and are minimally invasive. , , Additional advantages include less blood loss, shorter operative time, and no secondary incision or hardware to remove. , , The relatively simple suspension method of Huang et al. incorporated subcoracoid and transclavicular passage of large, nonabsorbable sutures through tunnels at the sites of the conoid and trapezoid ligament footprints. Concomitant CC ligament repair can be performed and is noted to be one of the most important components of the repair technique. , The potentially less invasive aspects of some newer implants, such as high-tensile sutures with EndoButton fixation, has been recently advocated. , ,


Biomechanical investigations


Along with their biomechanical properties, suture augmentation(s) act as a temporary internal splint, maintaining reduction of the AC joint until ligamentous healing is complete. There is growing evidence, mostly experimental, that supports a strategy of repair or reconstruction that includes both the AC and CC ligaments.


Wickham et al. compared the maximum tensile strength and resistance to deformation of different synthetic suture devices. Failure loads comparable with the intact CC ligament (725 N) were observed with synthetic suture devices passed around or through the clavicle; failure loads of a 6.5-mm screw with single-cortex purchase in the coracoid were around one-half those of the intact CC ligaments. Martetschläger et al. concluded that inferior biomechanical properties of braided PDS sutures used to reconstruct the AC and CC ligaments were responsible for failure to achieve vertical stability.


In experimental repairs performed by Wellmann et al., loop or button fixation of PDS exhibited significantly higher ultimate loads than did coracoid suture anchor repairs with No. 2 high-strength polyethylene (Ultrabraid) sutures. In a cadaver model, AC joint congruity was not restored by any CC loop fixation through drill holes in the clavicle but was more closely restored when the drill hole was placed more anteriorly in the clavicle.


Different configurations of synthetic suture constructs have been investigated in biomechanical studies. Abat et al. determined that passage via double tunnels in both the clavicle and the coracoid resulted in a reconstruction close to the native state compared with a single tunnel in the coracoid. Schliemann et al. compared the coracoid-side flip-button tendon graft with tendon looping around the coracoid with synthetic suture augmentation and found the biomechanical properties of these reconstructions to be comparable. When looping suture around the clavicle, increased abrasive wear might occur, in contrast to securing suture loops through drill holes in the clavicle; however, this observation is limited to a biomechanical study using a modified Weaver-Dunn technique. Moreover, the use of a transosseous TightRope (Arthrex Inc.) method rather than fiber mesh cerclage for CC augmentation resulted in less translational motion. Walz et al. demonstrated the efficacy of the dual tunnel TightRope technique with buttons in reproducing and exceeding the vertical and horizontal forces of the native CC ligaments. In addition, Lädermann et al. demonstrated the advantages of AC and CC cerclage over V-shaped orientation synthetic suture CC reconstruction and a hook plate.


Various methods of creating clavicular and coracoid tunnels for passing synthetic sutures, with or without biologic augmentation, and methods to secure such sutures and/or grafts (i.e., cortex-preserving devices/buttons) have been described. , Beitzel et al. identified no difference between one and two tunnels in the clavicle. , , As a result of an in-depth biomechanical investigation and early clinical experience, recommendations have been made regarding tunnel size, position, and spacing in the clavicle and coracoid process. , Rylander et al. demonstrated the benefits of a 4-mm versus a 6-mm tunnel in the clavicle. According to Spiegl et al., a hamstring tendon graft placed through 6-mm tunnels significantly weakened the clavicle compared with a cortical button and suture placed through 2.4-mm tunnels. Dumont et al. determined that the use of tunnels in the clavicle for CC ligament reconstruction reduces the load to failure, with interference screws not significantly increasing the strength of the construct. However, this study was conducted using a sawbone model without the use of additional tendon graft; thus the clinical significance of these findings remains uncertain. Ferreira et al. demonstrated that load-to-failure testing of a 6-mm tunnel through the coracoid process was significantly higher when the entry and exit of the tunnel was center-and-center or medial-and-center, respectively. The mechanism of failure was predominantly in the repair construct and not a fracture of the coracoid. In a three-dimensional virtual shoulder model, Coale et al. were able to highlight the significant risks when attempting to restore the anatomic footprint of the conoid and trapezoid ligaments. In their model, it was not possible to create reconstruction tunnels that both restored anatomic ligament footprints and maintained, without significant risk of cortical breach and fracture, the integrity of the bone through which the tunnels pass. In a similar model, Xue et al. observed a 90.5% incidence of clavicle or coracoid cortical breach with collinear drilling of a 4-mm tunnel based on anatomic landmarks. , Furthermore, image-free navigated CC drilling was shown to have a higher first-pass accuracy compared with a conventional drill guide–based technique and therefore may allow for more precise anatomic positioning and subsequently reduces the risk of iatrogenic coracoid fracture. In a matched-pairs cadaver study of coracoid tunnels, Campbell et al. determined that cortical button fixation strength was greater with a 4.5-mm tunnel compared with a 6-mm tunnel. In their study, central and proximal fixation was stronger than eccentric and distal fixation.


Surgical outcomes and complications


Currently, studies that report the clinical and radiographic outcomes of AC joint reconstruction using synthetic devices and augmentations have demonstrated inconsistent results. Methods that temporarily transfix the AC Joint with pins can produce good and excellent results , , , , , , ; however, fair and poor results are being reported by the same authors. ,


Direct AC and CC ligament repair via transosseous sutures that were protected with a temporary 4.5-mm CC screw for 8 weeks resulted in excellent clinical and radiographic outcomes at a mean follow-up of 72 months. Verdano et al. reported a mean C-M score of 92.7, Disabilities of the Arm, Shoulder and Hand (DASH) score of 3.2, and Simple Shoulder Test (SST) score of 11.4. Reduction was maintained (<3 mm) in 85.7% of patients. Lizaur et al. reported satisfactory and pain-free clinical outcomes in 92.1% of cases after a mean follow-up of 24.2 years. Radiographically, reduction was maintained in 86.8%, and the incidence of moderate to severe OA of the AC joint was 16%.


The PDS triple cerclage technique described by Sandmann et al. resulted in 94% excellent and good results. In addition, they found a CC distance less than 5 mm in 85%, 5 to 10 mm in 12%, and more than 10 mm in 3% of the cases; however, the measured CC distance did not correlate to clinical outcomes in this study.


Bone-encircling and bone-engaging fixation with a multitude of flexible materials produce generally favorable clinical outcomes. , , , , , , If desired, return to preinjury activity levels can be expected. , , , , , Martetschläger et al. identified an 83% survivorship rate at 2 years using these techniques. Implants specifically designed for initial mechanical and supplemental biologic stabilization demonstrate a favorable immunologic response and a histologic response that suggest a functioning implant. Using a PDS cerclage, Greiner et al. reported favorable patient-reported outcome scores (C-M of 91.7, DASH of 5, and subjective shoulder value (SSV) of 92); radiographically, a CC interval increase of more than 5 mm was observed in 20% and AC joint arthritis in 36% of patients after a mean follow-up of 70 months.


Favorable clinical outcome scores can be expected with transclavicular nonabsorbable sutures secured to the coracoid with suture anchors, , with or without additional suture anchor fixation across the AC joint. Transosseous sutures spanning the CC interval may also be secured through EndoButton fixation on the lateral clavicle. , Using this technique, early (i.e., mean follow-up of 12 to 18 months) clinical success rates of nearly 90% together with radiographic stability restoration have been reported. , , , , , At a mean follow-up of 24 months, De Carli et al. noted high outcome scores. Furthermore, Yi and Kim recognized that when the surgeon controls variables of clavicle and coracoid tunnel alignment (i.e., oriented as perpendicularly as possible), both clinical and radiographic outcomes are observed. Shin and Kim reported a mean C-M score of 97.5 at 25.6 months; loss of reduction did not influence the C-M score significantly. With a slightly longer follow-up (mean, 39 months), Rosslenbroich et al. reported a mean C-M of 94.7 and a mean Taft score of 10.8 using similar techniques. In this study, the influence of age on clinical outcomes was observed, with younger patients achieving higher outcome values.


The clinical results of AC joint reconstruction using synthetic ligament devices such as a Ligastic, LARS, or double-braided polyester indicate high subjective satisfaction rates and good outcomes. However, some patients complained of residual pain (33%), scar concerns (7%), shoulder weakness (1%), work issues (1%), and sport issues (1%). A greater CC distance on the operative side did not adversely affect clinical outcomes. Even though the efficacy of the LARS device has been demonstrated in clinical trials, , , structural failures of this device leading to inferior clinical outcomes have also been noted. ,


Anatomic coracoclavicular ligament reconstruction


In the past decade, there has been a significant trend to seek a more anatomic and biologic solution for CC ligament reconstruction. The notion is that reliable restoration of function and comfort is dependent on the durable restoration of anatomic parameters, including the congruency and stability of the AC joint. The method often includes substituting synthetic and/or biologic material for each CC ligament separately entering the clavicle and coracoid as close as possible to the footprints of the native ligaments.


Early biomechanical investigations followed the initial report of Jones et al., who described a surgical technique using an autologous semitendinosus tendon, and applied the method in a revision case. , , , , , Mazzocca et al. were among the earliest advocates for so-called anatomic coracoclavicular ligament reconstruction (ACCR) using autograft or allograft tendon to replicate the CC ligaments at their anatomic location ( Fig. 22.14 ). Biomechanically, this has been shown to be more effective in mimicking the properties of the native CC ligaments compared with ligament transfers. Moreover, using the ACCR technique, high subjective satisfaction scores and rates with favorable clinical outcomes have been reported. , , , ,




Fig. 22.14


A coracoclavicular reconstruction that is considered anatomic uses autograft or allograft tendon.

(Modified from Mazzocca AD, Conway J, Johnson S, et al. The anatomic coracoclavicular ligament reconstruction. Oper Tech Sports Med . 2004;12:56–61.)


Additional biomechanical work by Lee et al. led to the first clinical application and report of the use of autologous hamstring tendon by Nicholas et al. , Subsequently, anatomic reconstruction techniques using autogenous or allogenous tendon have been reported as a preferred method of treatment. , , Historically, a similar method was eloquently described in 1928 by Bunnell, who incorporated a fascial graft weave that offered stability between the clavicle and the scapula at both sites.


Biomechanical investigations


The concept of surgical recreation of both CC ligaments has been supported, both theoretically and experimentally. , , The utility and efficacy of using an intramedullary free tendon graft in vitro have been demonstrated. The requirement for a biologic graft may not be dependent on the strength of the reconstruction, which can be comparably achieved with nonbiologic materials, but rather the necessity of a biologic substrate. Experimental reconstructions with semitendinosus tendon graft can reproduce peak loads equivalent to that of the native CC ligaments , ; however, there is lower stiffness. Furthermore, anatomic reconstruction with a semitendinosus tendon failed to demonstrate significant elongation under cyclic loading.


Anatomic allograft reconstructions such as ACCR have demonstrated superior load-to-failure characteristics in contrast to other techniques such as the modified Weaver-Dunn, nonanatomic allograft, anatomic suture, and graft-rope techniques. Dierckman et al. have demonstrated superior biomechanical properties when the anatomic reconstruction is supplemented with a hook plate, although no difference in maximum load-to-failure was found. According to Grutter and Mazzocca, anatomic reconstruction of the CC ligaments best restores the biomechanical properties of the native CC ligaments. , Tunnel placement in the clavicle corresponding to the attachment of the CC ligaments has the highest bone mineral density and correlates to higher loads to failure experimentally. Tunneling the graft through as opposed to around the coracoid (i.e., “looping”) can be performed. , , Looping the graft around the coracoid results in more pure anterior translation of the clavicle compared with a transcoracoid tunnel technique. , Also, by creating an excessive tunnel in the coracoid, the risk for postoperative fractures increases. Fixation of the graft within the clavicle can be performed using biointerference screws and the fixation strength further enhanced with suture augmentation (i.e., internal brace). ,


Horizontal and rotational instability of the AC joint following reconstruction remains a major concern that cannot be overcome by isolated CC reconstruction techniques. Persistent horizontal and rotational instability after AC joint separations may lead to chronic pain in the shoulder; therefore special attention to this challenging patient cohort must be made. , The posterior and superior aspects of the AC capsular ligaments are known to significantly contribute to horizontal and rotational stability. , Almost 80% of the horizontal stability is provided by an intact superior-posterior capsuloligamentous joint complex. Therefore such structures may be insufficient in cases of chronic ACJI. , , Beitzel et al. and Grantham et al. reported in their biomechanical studies that horizontal and rotational stability can be restored when reconstructing the AC capsule. , Furthermore, the benefit of augmenting the deficient AC capsule with a cerclage-type construct has been demonstrated in both biomechanical and clinical studies. , , , In patients with persistent horizontal instability, anatomic AC joint reconstruction is favored. , To anatomically reproduce the insertions of the AC ligaments at the acromion, the posterior-medial acromion closest to the AC joint reveals the highest bone marrow density with increasing density from lateral to medial; therefore fixation in this location might be favorable. In addition, tunnels placed at the acromion within the “safe zone” (i.e., within the anterior half of the acromion) do not affect the load-to-failure at the acromion. However, persistent rotational instability remains a concern and may play a significant role in AC joint reconstruction failures. , Future research is warranted in this area.


Surgical outcomes and complications


Open techniques deemed “anatomic” reveal definite improvements in both pain and function, , with an ASES score of 92 and C-M score of 94.7, yielding an overall success rate of 82%. Similar outcomes with respect to ASES scores, as well as favorable Single Assessment Numerical Evaluation scores (89.1), QuickDASH (5.6), and excellent satisfaction, were reported by Millett et al. Radiographic reduction was maintained in 82% of the patients in this study. Arthroscopic-assisted techniques with interference screw autograft fixation in bone tunnels (i.e., clavicle and coracoid) yielded a C-M score of 96.6, minimal (<2 mm) to mild (2 to 4 mm) displacement, and excellent functional and subjective outcomes.


Recently, Muench et al. reported on 43 patients undergoing ACCR for acute and chronic type III and V AC joint injuries. In their study the patients maintained significant improvement in clinical and radiographic outcomes at a minimum 2-year follow-up, with 81% of patients reaching a substantial clinical benefit after surgical reconstruction.


The results of using autologous tendon indicate both efficacy and safety when grafts such as gracilis are used. A comparison study analyzing the results of reconstruction with Ethibond sutures through tunnels and semitendinosus autograft demonstrated no clinical or radiographic differences.


Authors’ preferred surgical method for acromioclavicular joint injuries type III to VI


Our preferred method for type III to VI injuries is the ACCR technique. , , , At our institution, patients presenting with acute or chronic type III to VI injuries undergo minimum 6 weeks of nonoperative management, which includes physical therapy. Thus patients who do not respond to a trial of conservative management are indicated for conversion to the ACCR technique. For both groups, good function and clinical outcomes may be expected , , , ; however, time from injury to surgery may have an influence on postoperative clinical or radiographic complications such as HO, loss of reduction, or clinical failure. , Moreover, Muench et al. and Berthold et al. demonstrated that greater complications for patients with longer time from injury to surgery (>6 months) may be expected. ,


Surgery starts with the patient in the beach chair position. An incision is made starting at the posterior edge of the clavicle, 3.5 cm medial to the AC joint, and extending inferiorly toward the coracoid process. The incision can be placed obliquely to have full visualization of the AC joint laterally and the coracoid process medially. Dissection is performed down to the deltotrapezial fascia with electrocautery. Full-thickness fascioperiosteal flaps are elevated off the clavicle. All soft tissues preventing proper joint reduction are resected and a trial reduction is performed. This includes upward displacement of the scapulohumeral complex combined with the use of a reduction forceps placed on the posterosuperior clavicle and on the undersurface of the coracoid process. The most distal end of the clavicle should be freed from trapezius muscle, hypertrophic scar tissue, and/or capsular remnants ( Figs. 22.15 and 22.16 ). Care is taken not to damage the distal clavicle.


Aug 21, 2021 | Posted by in ORTHOPEDIC | Comments Off on Open management of atraumatic and traumatic disorders of the acromioclavicular joint: Indications, techniques, and outcomes

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