Acromioclavicular Ligaments Research Articles

Risk of fracture of the acromion depends on size and orientation of acromial bone tunnels when performing acromioclavicular reconstruction

Current techniques for anatomic repair of the dislocated acromioclavicular (AC) joint aim on reconstruction of the AC ligaments and utilize tunnels drilled through the acromion . This improves the stability of the reconstruction but might also increase the risk of fractures at the acromion. The purpose of this study was to evaluate the fracture risk for the acromion after transacromial tunnel placement for anatomic AC joint stabilization procedure. It was hypothesized that the risk of fracture of the acromion is correlated to size and orientation of bone tunnels commonly used for anatomic AC joint reconstruction. A finite element analysis was used to simulate multiple bone tunnels and incoming force vectors (lateral vs. superior). Different tunnels were analysed, horizontal meaning an anterior-posterior orientation versus a vertical inferior-superior orientation through the acromion. Two tunnel diameters were simulated (2.4 vs. 4.5mm). Furthermore, the tunnel length and distance between tunnels were altered. Forty-five cadaveric specimens (median age: 64years, range 33-71years) were utilized for data acquisition. Out of these, 30 specimens were used to evaluate basic tunnel orientations and drill diameters using a MTS 858 servohydraulic test system. With regard to the tunnel orientation and drill hole size, the loads to failure were limited. The acromion is at higher fracture risk, with a superior to inferior directed incoming force. Position, size and direction of bone tunnels influenced the loads to failure. Horizontal tunnels with a higher diameter (4.5mm) had the most impact on load to failure reduction. A long horizontal tunnel with a diameter of 4.5mm reduced the load to failure with medial direction of force to 25% of the native acromion. The identical tunnel with a diameter of 2.4mm reduced the load to failure to 61%. Both 2.4-mm horizontal tunnels with a medium and short length did not reduce the load to failure. Tunnels placed at the acromion did not result in an increased risk of fracture. However, descriptive data showed a tendency for an increased fracture risk if tunnels are placed at the acromion, especially in horizontal direction with diameters of 4.5mm. In addition, the pattern of fracture was dependent on the orientation of the bone tunnels and the size. However, the results indicate a "safe zone" for the placement of bone tunnels within the anterior half of the acromion, which does not affect the loads to failure at the acromion. Therefore, current techniques for anatomic AC joint reconstruction which utilize fixation of grafts or sutures at the acromion are safe within current ranges of tunnel placement and sizes.

Functional and radiological outcomes of acromioclavicular joint reconstruction in type iii disruption without allograft with synthetic materials

Introduction: Effectiveness of surgery for complete Acromio-clavicular Joint (ACJ) dislocation is controversial. We analyzed the long-term Functional and radiological outcome after in on Acromio-clavicular ligament reconstruction by modified Mazzocca technique for Type 3 dislocations. Aim: To study the functional and radiological outcomes of acromioclavicular joint reconstruction in type III disruption without allograft with synthetic materials Method: Retrospective analysis of case records and patient reviewed to assess the long-term functional and radiological outcome by patient satisfaction, UCLA shoulder rating score and coracoclavicular distances. Results: We had 38 cases of Type 3 Acromio-clavicular dislocations over a period of 5 years. Mean age of the entire group was 42.1 years (26 to 57). Among them, 32 are males and six females. Three patients were lost their follow-up during the post-op rehabilitation period; among them, two were presented with infection, one with shoulder stiffness. Long-term functional and radiological outcomes were regarding UCLA shoulder rating score, patient satisfaction and coracoclavicular distances compared with the uninjured shoulder. Conclusions: More aggressive management of acromioclavicular dislocation needed to avoid poor results with chronic injuries, and we have moved toward without graft and earlier surgical intervention. We recommend modified Mazzocca technique used in the management of Grade 3 Acromio-clavicular joint dislocation for the following reasons (A). Better short-term functional and radiological outcome and low risk of complications (B). No need graft harvesting surgery and decreased donor site morbidity.

Anatomic ligament consolidation of the superior acromioclavicular ligament and the coracoclavicular ligament complex after acute arthroscopically assisted double coracoclavicular bundle stabilization.

The consolidation of the acromioclavicular (AC) and coracoclavicular (CC) ligament complex after arthroscopically assisted stabilization of acute acromioclavicular joint (ACJ) separation is still under consideration. Fifty-five consecutive patients after arthroscopically assisted double-CC-bundle stabilization within 14days after acute high-grade ACJ separation were studied prospectively. All patients were clinically analysed preoperatively (FU0) and post-operatively (FU1=6months; FU2=12months). The structural MRI assessments were performed at FU0 (injured ACJ) and at FU2 bilateral (radiologic control group) and assessed separately the ligament thickness and length at defined regions for the conoid, trapezoid and the superior AC ligament. Thirty-seven patients were assessed after 6.5months and after 16.0months. The 16-month MRI analysis revealed for all patients continuous ligament healing for the CC-complex and the superior AC ligament with in the average hypertrophic consolidation compared to the control side. Separate conoid and trapezoid strands (double-strand configuration) were detected in 27 of 37 (73%) patients, and a single-strand configuration was detected in 10 of 37 (27%) patients; both configurations showed similar CCD data. The ligament healing was not influenced by the point of surgery, age at surgery and heterotopic ossification. The clinical outcome was increased (FU0-FU2): Rowe, 47.7-97.0 pts.; TAFT, 3.9-10.6 pts.; NAS pain, 8.9-1.4 pts. (all P<0.05). The arthroscopically assisted double-CC-bundle stabilization within 14days after acute high-grade ACJ separation showed 16months after surgery sufficient consolidations of the AC and double-CC ligament complex in 73%. III, Case series.

Biomechanical evaluation of native acromioclavicular joint ligaments and two reconstruction techniques in the presence of the sternoclavicular joint: A cadaver study.

Where is over 100 reconstruction techniques described for acromioclavicular (AC) joint reconstruction. Although, it is not clear whether the presence of the sternoclavicular (SC) joint influences the biomechanical properties of native AC ligaments and reconstruction techniques. The purpose of the present study was to investigate the biomechanical properties of native AC joint ligaments and two reconstruction techniques in cadavers with the SC joint still present. We tested eight fresh-frozen cadaver hemithoraces for superior translation (70 N load) and translation increment after 1000 cycles (loading from 20 to 70 N) in a controlled laboratory study. There were three testing groups created: native ligaments, the single coracoclavicular loop (SCL) technique, and the two coracoclavicular loops (TCL) technique. Superior translation was measured after static loading. Translation increment was calculated as the difference between superior translation after cyclic and static loading. Native AC ligaments showed significantly lower translation than the SCL ( p = 0.023) and TCL ( p = 0.046) groups. The SCL had a significantly lower translation increment than native AC ligaments ( p = 0.028). There was no significant difference between reconstruction techniques in terms of translation ( p = 0.865) and translation increment ( p = 0.113). Native AC joint ligaments had better static properties than both reconstruction techniques and worse dynamic biomechanical properties than the SCL technique. The SCL technique appeared to be more secure than the TCL technique. The presence of the SC joint did not have an observable influence on test results.

Surgical treatment of acute type V acromioclavicular joint dislocations in professional athletes: an anatomic ligament reconstruction with synthetic implant augmentation

Most acromioclavicular (AC) joint injuries occur in men in their third decade of life during high-speed or high-impact body contact sports. The management of acute complete AC joint dislocation is surgical. Current surgical techniques include anatomic reconstruction of the main restraints of the AC joint and aim to improve functional outcomes and to reduce the complication rate. We present 10 cases of acute type V AC joint dislocation in professional athletes treated surgically with anatomic reconstruction of the coracoclavicular and AC ligaments and augmentation with the use of a synthetic polyester tape. The minimum follow-up of the patients was 2 years (mean, 48 months; range, 24-86 months). The postoperative functional outcome was assessed at 1 year and 2 years using the Constant-Murley, American Shoulder and Elbow Surgeons, and modified University of California-Los Angeles scoring systems. In all cases, the postoperative scores were significantly improved (P < .005 in all comparisons with the preoperative scores), and all patients returned to their preinjury high level of activity 6 months postoperatively. Radiographs at 1 month and 6 months revealed the maintenance of reduction. There were no complications. According to the results of our series of patients, demanding cases of acute AC joint dislocation Rockwood type V, in professional athletes, require anatomic fixation of both coracoclavicular and AC ligaments for return to sports as soon as possible and at the preinjury level of performance.

A Single-Tunnel Technique for Coracoclavicular and Acromioclavicular Ligament Reconstruction

Acromioclavicular (AC) joint separation is a common injury seen in the young adult athletic population. Both the indications for surgical management and the best operative technique remain controversial. One of the most popular reconstruction techniques is the anatomic double-tunnel coracoclavicular (CC) ligament reconstruction. However, there have been several case reports of clavicle fractures with this technique. This article presents a single-tunnel reconstruction technique that aims to restore both the CC and AC ligament function, while minimizing fracture risk.

Surgical Technique for Arthroscopy-Assisted Anatomical Reconstruction of Acromioclavicular and Coracoclavicular Ligaments Using Autologous Hamstring Graft in Chronic Acromioclavicular Joint Dislocations

Injuries to the acromioclavicular (AC) joint are becoming common with contact sports and bike accidents. It is well known that in AC dislocations, the first structure to fail is the AC capsule followed by the trapezoid and conoid ligaments. The function of these ligaments must be restored to restore the anatomy and physiology of the AC joint to get the best results. Until now, no technique has emerged as the gold standard for restoration of the AC joint anatomy and function. In our technique, the stress is on recreating the anatomy to make it more individualized based on individual variations. This Technical Note describes a procedure to reconstruct the coracoclavicular ligaments and AC joint by an arthroscopy-assisted technique. Arthroscopy helps to diagnose additional intra-articular pathologies that can be treated simultaneously, and better preparation of the undersurface of the coracoid helps in bone-to-graft healing. Our approach is more individualized as clavicle tunneling is done according to the size of the coracoid base instead of a fixed distance. Vertical stability is provided by coracoclavicular ligament reconstruction, horizontal stability is provided by AC ligament reconstruction, and the articular disc is recreated by soft-tissue graft interposition, thus restoring the complete anatomy.

CT measurement and clinical application of double-row suture anchor reconstruction for the treatment of Tossy type III acromioclavicular joint dislocation

To study feasibility and reliability of reconstruction of the acromioclavicular ligament with double-row suture anchor for the treatment of acromioclavicular joint dislocation through coracoid coronal CT measurement, and to provide a new operation method for treating acromioclavicular joint dislocation. Total 60 healthy people received CT examination of shoulder joint, including 30 males and 30 females, ranging in age from 18 to 50 years old. The coronal width, thickness and 20 degree camber angle in the medial part of the toot of coronal were measured using CT scan. The results were applied to clinical treatment for 12 patients with acromioclavicular joint dislocation of Tossy III type. The width in the medial part of the root of the coracoid was(17.65±1.82) mm(left side) and (17.67±1.80) mm(right side) in males; (16.55±1.78) mm(left side) and (16.52±1.74) mm (right side) in females. The vertical thickness of the roots of the coracoid: (13.11±2.11) mm(left side) and (13.16±2.09) mm(right side) in males;(12.79±2.21) mm(left side) and (12.76±2.19) mm (right side) in females. The thickness of 20 degrees camber angle of the coracoid roots: (16.32±1.74) mm (left side) and (16.30±1.69) mm(right side) in males; (15.68±1.44) mm(left side) and (15.67±1.43) mm(right side) in females. Total 12 patients were treated with anchor nail with extraversion 20 degrees. The postoperative X-ray films showed bone anchors were located in the coracoid process, no bone splitting. Double-row suture anchor of 5 mm diameter nails can be placed into coracoid with extraversion 20 degrees, which is safety.

Acromion morphology and bone mineral density distribution suggest favorable fixation points for anatomic acromioclavicular reconstruction.

Recent techniques for acromioclavicular (AC) joint reconstruction focus on additional AC cerclage to coracoclavicular (CC)-reconstructions. Due to the specific slim bone morphology at the acromion, there are concerns regarding these additional bone tunnels, as they may predispose to fracture and break out. The purpose of this study was to investigate anatomic properties of the acromion which may help improve surgical techniques directed at injuries to the AC joint. It was hypothesized that via measurements of thickness and density points of increased strength and support could be identified on the acromion. Eighty-five fresh frozen cadaveric shoulders were used for this study. A standardized 3D-net was developed and thicknesses of the acromion were taken from defined points using a certified caliper. To define the acromial arch, the angle and radius of curvature between the antero-lateral, the highest point of the acromial arch and the postero-lateral aspect of the acromion were measured. Additional bone mineral density (BMD) evaluation was performed on 43 specimens in an anterio-posterior and latero-medial direction using 5-mm slices with a maximum of 10 and 6 slices, respectively. Median specimen age was 63.0 (range 36) years (55 female, and 30 male). There was no statistical significance between male (62.0, range: 35 years) and female (64.5, range 32 years) regarding age (n.s.). Thickness of acromion points of interest were ranging from 3.5 to 24.3mm. Median radius of curvature of acromial arch for female was 48.2 (range 92.7) mm and 66.2 (range 85.6) for male (p = 0.019). The median angle for female specimens was 21.4° (range: 44.6°) and 23.3° (range 51.7°) for male (p = 0.047). The latero-medial measurements showed significant difference between the region of interest (ROI): 1 and 4, 5, 6 (p = 0.001, p = 0.001, p = 0.001), 2 and 4, 5, 6 (p = 0.007, p = 0.001, p = 0.001), 3 and 5, 6 (p = 0.001, p = 0.001), 4 and 5, 6 (p = 0.010, p = 0.001). Antero-posterior measurements showed significant difference between the ROI: 1 and 8 (p = 0.031). The posterior-medial acromion close to the AC joint revealed the highest BMD with an increasing density from lateral to medial. In combination with thickness measurements this region would support additional anatomical fixation of the AC joint using bone tunnels if necessary. To anatomically reproduce the insertions of the AC ligaments at the acromion, either bone tunnels or anchors are needed. Therefore, several techniques have been developed. This study provides the anatomical data for these techniques and confirms the reconstructive approach of techniques using anatomical points of fixation and orientation.

Arthroscopic Technique for Stabilization of Chronic Acromioclavicular Joint Instability With Coracoclavicular and Acromioclavicular Ligament Reconstruction Using a Gracilis Tendon Graft

We present an arthroscopic technique for stabilization of chronic acromioclavicular (AC) joint instability using a transclavicular-transcoracoidal button technique, combined with a coracoclavicular and AC ligament reconstruction using the gracilis tendon. This arthroscopic technique achieves an anatomic reduction of the clavicle without further implant removal. It ensures vertical and horizontal stabilization of the AC joint. Using a horizontal drill hole through the clavicle and looping the gracilis tendon graft around the coracoid avoids weakening of the coracoid with the risk of fracture.

Arthroscopic Distal Clavicle and Medial Border of Acromion Resection for Symptomatic Acromioclavicular Joint Osteoarthritis

Acromioclavicular joint osteoarthritis can lead to persistent shoulder pain. Distal clavicle excision is the most common operative procedure in patients with failed, conservative symptomatic acromioclavicular joint osteoarthritis treatment, with some reports of complications. This report describes an alternative procedure that can be used to excise the distal clavicle together with the medial border of the acromion. This technique is a simple procedure because the standard distal clavicle excision can preserve the acromioclavicular ligament, as well as the joint capsule, and achieve an adequate resection length.

Reconstruction of coracoclavicular and acromioclavicular ligaments under small incision for the treatment of old acromioclavicular joint dislocation.

Reconstruction of coracoclavicular and acromioclavicular ligaments under small incision for the treatment of old acromioclavicular joint dislocation.

BiPOD Arthroscopic Acromioclavicular Repair Restores Bidirectional Stability.

Stabilizing the acromioclavicular joint in the vertical and horizontal planes is challenging, and most current techniques do not reliably achieve this goal. The BiPOD repair is an arthroscopically assisted procedure performed with image intensifier guidance that reconstructs the coracoclavicular ligaments as well as the acromioclavicular ligaments to achieve bidirectional stability. Repair is achieved with a combination of 2-mm FiberTape (Arthrex, Naples, Florida) and 20-mm Poly-Tape (Neoligaments, Leeds, England) to achieve rigid repair, prevent bone abrasion, and promote tissue ingrowth. This study is a prospective review of the first 6 patients treated for high-grade acute acromioclavicular injury with the BiPOD technique. The study included 6 men who were 21 to 36 years old (mean, 27 years). At 6-month follow-up, complications were recorded and radiographic analysis was used to determine the coracoclavicular distance for vertical reduction and the amount of acromioclavicular translation on the Alexander axillary view was used to determine horizontal reduction. One patient had a superficial infection over the tape knot. The difference in coracoclavicular distance between the operated side and the uninvolved side was 9±2 mm preoperatively and 0.3±2 mm at 6-month follow-up. On Alexander axillary view, all 6 patients showed stable reduction, which is defined as a clavicle that is in line with the acromion. The findings show that BiPOD acromioclavicular reconstruction restores bidirectional stability of the acromioclavicular joint at 6 months. [Orthopedics. 2017; 40(1):e35-e43.].

Arthroscopic-assisted Acromioclavicular and Coracoclavicular Ligaments Reconstruction for Chronic Acromioclavicular Dislocations: Surgical Technique.

Chronic acromioclavicular (AC) instability is a rare posttraumatic shoulder condition that can lead to undesirable symptoms like persistent pain, muscle fatigue, loss of strength, or even scapular dyskinesis. It is well known that in these cases the superior functional results depend on the restoration of the anatomy and stability of the AC joint in both vertical and horizontal planes. Considering the ligaments degeneration and atrophy in chronic AC joint dislocations, we present an arthroscopic-assisted reconstruction of both the coracoclavicular and AC ligaments using autograft augmentation. In details the coracoclavicular ligaments component is reconstructed using the Tightrope suspension device augmented with a palmaris longus autograft and by the nonanatomic coracoacromial ligament transfer (modified Weaver-Dunn). The AC part is restored by suturing the remainder palmaris longus autograft on the acromion and on the deltotrapezial fascia. Using the construct provided by this technique all the possible ruptured ligaments are reconstructed, optimizing the vertical and horizontal stability of the area, and promising excellent long-term radiologic and functional results.

Influence of disruption of the acromioclavicular and coracoclavicular ligaments on glenohumeral motion: a kinematic evaluation.

BackgroundChanges to the integrity of the acromioclavicular (AC) joint impact scapulothoracic and clavicular kinematics. AC ligaments provide anterior-posterior stability, while the coracoclavicular (CC) ligaments provide superior-inferior stability and a restraint to scapular internal rotation. The purpose of this cadaveric study was to describe the effect of sequential AC and CC sectioning on glenohumeral (GH) kinematics during abduction (ABD) of the arm. We hypothesized that complete AC ligament insult would result in altered GH translation in the anterior-posterior plane during abduction, while subsequent sectioning of both CC ligaments would result in an increasing inferior shift in GH translation.MethodsSix cadaveric shoulders were studied to evaluate the impact of sequential sectioning of AC and CC ligaments on GH kinematics throughout an abduction motion in the coronal plane. Following an examination of the baseline, uninjured kinematics, the AC ligaments were then sectioned sequentially: (1) Anterior, (2) Inferior, (3) Posterior, and (4) Superior. Continued sectioning of CC ligamentous structures followed: the (5) trapezoid and then the (6) conoid ligaments. For each group, the GH translation and the area under the curve (AUC) were measured during abduction using an intact cadaveric shoulder. Total translation was calculated for each condition between ABD 30° and ABD 150° using the distance formula, and a univariate analysis was used to compare total translation for each axis during the different conditions.ResultsGH kinematics were not altered following sequential resection of the AC ligaments. Disruption of the trapezoid resulted in significant anterior and lateral displacement of the center of GH rotation. Sectioning the conoid ligament further increased the inferior shift in GH displacement.ConclusionA combined injury of the AC and CC ligaments significantly alters GH kinematics during abduction. Type III AC separations, result in a significant change in the shoulder’s motion and may warrant surgical reconstruction to restore normal function.

Treatment of Symptomatic Acromioclavicular Joint Instability by a Docking Technique: Clinical Indications, Surgical Technique, and Outcomes

To report functional and objective outcomes resulting from surgical treatment of patients with symptomatic type III through V acromioclavicular (AC) joint injury by use of a modification of the anatomic AC joint reconstruction developed by Carofino and Mazzocca. The study included all patients treated in 2009-2014 who presented with a history of direct trauma to the shoulder; deformity of the AC joint on clinical examination; radiographic findings that would classify the injury as a Rockwood type III, IV, or V injury; AC joint instability on clinical examination; and self-reported deficits of arm function on initial presentation, in whom a comprehensive and directed nonoperative program failed. The surgical procedure used an allograft with reinforcing internal sutures passed around the coracoid and through anatomically positioned clavicular holes for the coracoclavicular (CC) ligaments, used a docking technique for reconstruction of the superior AC ligaments, and included repair of the native AC ligaments. Outcomes were reported for patients with a minimum follow-up period of 1.5years. Outcome measurements included dynamic-static stability evaluation and Disabilities of the Arm, Shoulder and Hand (DASH) scores. The study included 15 patients with 15 affected shoulders. The postsurgical follow-up period averaged 3years (range, 1.5-5years). Postoperatively, one patient showed loss of reduction after a fall. All others showed 2-dimensional radiographic stability and 3-dimensional dynamic clinical stability. Static radiographic measurement of the CC distance at discharge averaged 0.93cm compared with 2.7cm on initial examination (P < .0001). Patient-reported outcomes at an average of 3years' follow-up showed a DASH score of 13 compared with a preoperative DASH score of 51 (P < .0001). This study confirms that anatomic CC ligament reconstruction and repair or reconstruction of the AC ligaments help restore arm function as shown by the patient-specific and clinical outcome metrics. These results were achieved by correction of the deformity, which in turn allowed for the obtainment of static and dynamic stability. Level IV.

Arthroscopically Assisted Acromioclavicular and Coracoclavicular Ligament Reconstruction for Chronic Acromioclavicular Joint Instability

Acromioclavicular (AC) joint injuries are common injuries, especially in the young and active, male population. AC joint injuries account for 12% of all injuries of the shoulder girdle in the overall population. Although conservative treatment is recommended for Rockwood type I and type II injuries, there is controversial debate about optimal treatment for type III injuries. High-grade injuries are typically treated operatively to avoid painful sequelae. A vast number of different surgical methods have been described over the past few decades. Recent advances in arthroscopic surgery have enabled the shoulder surgeon to treat acute and chronic AC lesions arthroscopically assisted. Clinical studies have already shown good and reliable results. Although surgeons agree that a biological augmentation is required to minimize the risk of recurrent instability in chronic cases, a gold standard still needs to be defined. We present an arthroscopically assisted biological augmentation technique to reconstruct the AC and coracoclavicular ligaments, protected by a button-suture tape construct for chronic AC joint instability. The presented arthroscopic biological augmentation technique uses less and/or smaller drill holes in the clavicle and coracoid than previously described, thus reducing weakening of the bony structures. At the same time it enhances both horizontal and vertical stability.

Biomechanical Analysis of Intra-articular Pressure After Coracoclavicular Reconstruction

Background: Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for surgical treatment of acromioclavicular instability. Concerns remain that such procedures can “overconstrain” (overreduce the lateral clavicle in relation to the acromion to a nonphysiological position) the joint. Purpose/Hypothesis: The purpose of this study was to investigate the intra-articular pressure of native and reconstructed acromioclavicular (AC) joints in relation to the configuration of the joint. Anatomic (0 mm), overconstrained (−3 mm), and underconstrained (+3 mm) AC joint reconstructions were simulated. The hypothesis was that reconstructions using suture pulley systems do not increase the intra-articular pressure of the AC joint. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen cadaveric shoulders were used in this study (mean age ± SD, 60.8 ± 6.7 years). Each specimen underwent radiographic analysis by using a Zanca view to determine the basic configuration of the AC joint. A pressure Tekscan sensor was inserted in the AC joint. A servohydraulic materials testing system was used for testing. The specimens were kept in the testing machine, and the native AC position was marked at 0 mm. This allowed moving the clavicle during the surgical procedure with reference to the native anatomic position. Intra-articular pressure in the native AC joint during cyclic loading (1000 cycles; 1 Hz) was measured. After native testing, the AC ligaments and coracoclavicular ligaments were cut and reconstructed using a cortical button technique. Anatomic, −3 mm, and +3 mm positions, relative to the acromion, were cyclically loaded, and intra-articular pressure was documented. Results: According to the AC joint classification of inclination, we identified five type 1 (46%), four type 2 (36%), one type 3 (9%), and one incongruous (9%) configurations. Changes in superior displacement across the 4 conditions were not statistically significant (0.5 ± 0.8 [native], 0.01 ± 0.00 [0 mm repair], 0.02 ± 0.02 [−3 mm repair], and 0.01 ± 0.01 [+3 mm repair]; P = .162). Before testing (time point 1), pressure in the −3 mm repair (62.9 ± 70.1) differed between the native state (11.3 ± 21.8; P = .042) and the +3 mm repair (7.1 ± 18.4; P = .023). All other changes at time points 2 (after cyclic loading unloaded) and 3 (after cyclic loading loaded) in pressure were not significant. (P = .086 and .226, respectively). Conclusion: AC joint reconstruction (within −3 to +3 mm of reduction) with a coracoclavicular suture button device does not significantly increase the intra-articular pressure of the AC joint after cyclic loading in our experimental cadaveric setup. Clinical Relevance: Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for coracoclavicular reconstruction of the joint. Concerns remain that such procedures would “overconstrain” the joint because of the high rigidity of these pulley systems and the preservation of the lateral clavicle. This overconstraining may potentially result in pain at the lateral end of the clavicle, osteolysis, or a later increased risk of early osteoarthritis. Therefore, our results indicate that within a range of ±3 mm to the anatomic position, overconstraining may not result in a higher intra-articular pressure.

Injury patterns of the acromioclavicular ligament complex in acute acromioclavicular joint dislocations: a cross-sectional, fundamental study.

BackgroundHorizontal instability impairs clinical outcome following acute acromioclavicular joint (ACJ) reconstruction and may be caused by insufficient healing of the superior acromioclavicular ligament complex (ACLC). However, characteristics of acute ACLC injuries are poorly understood so far. Purposes of this study were to identify different ACLC tear types, assess type-specific prevalence and determine influencing cofactors.MethodsThis prospective, cross-sectional study comprised 65 patients with acute-traumatic Rockwood-5 (n = 57) and Rockwood-4 (n = 8) injuries treated operatively by means of mini-open ACJ reduction and hook plate stabilization. Mean age at surgery was 38.2 years (range, 19–57 years). Standardized pre- and intraoperative evaluation included assessment of ACLC tear patterns and cofactors related to the articular disc, the deltoid-trapezoidal (DT) fascia and bony ACJ morphology. Articular disc size was quantified as 0 = absent, 1 = remnant, 2 = meniscoid and 3 = complete.ResultsAll patients showed complete ruptures of the superior ACLC, which could be assigned to four different tear patterns. Clavicular-sided (AC-1) tears were observed in 46/65 (70.8 %), oblique (AC-2) tears in 12/65 (18.5 %), midportion (AC-3) tears in 3/65 (4.6 %) and acromial-sided (AC-4) tears in 4/65 (6.1 %) of cases. Articular disc size manifestation was significantly (P < .001) more pronounced in patients with AC-1 tears (1.89 ± 0.57) compared to patients with AC-2 tears (0.67 ± 0.89). Other cofactors did not influence ACLC tear patterns. ACLC dislocation with incarceration caused mechanical impediment to anatomical ACJ reduction in 14/65 (21.5 %) of cases including all Rockwood-4 dislocations. Avulsion “in continuity” was a consistent mode of failure of the DT fascia. Type-specific operative strategies enabled anatomical ACLC repair of all observed tear types.ConclusionsAcute ACLC injuries follow distinct tear patterns. There exist clavicular-sided (AC-1), oblique (AC-2), midportion (AC-3) and acromial-sided (AC-4) tears. Articular disc size was a determinant factor of ACLC tear morphology. Mini-open surgery was required in Rockwood-4 and a relevant proportion of Rockwood-5 dislocations to achieve both anatomical ACLC and ACJ reduction. Type-specific operative repair of acute ACLC tears might promote biological healing and lower rates of horizontal ACJ instability following acute ACJ reconstruction.

Arthroscopic resection of the distal clavicle in osteoarthritis of the acromioclavicular joint.

Background:Symptomatic acromioclavicular joint (ACJ) lesions are a common cause of shoulder complaints that can be treated successfully with both conservative and surgical methods. There are several operative techniques, including both open and arthroscopic surgery, for excising the distal end of the clavicle. Here, we present a new modified arthroscopic technique for painful osteoarthritis of the ACJ and evaluate its clinical outcomes. Our hypothesis was that 4- to 7-mm resection of the distal clavicle in an en bloc fashion would have several advantages, including no bony remnants, maintenance of stability of the ACJ, and reduced prevalence of heterotopic ossification, in addition to elimination of the pathologic portion of the distal clavicle.Materials and Methods:20 shoulders of 20 consecutive patients with painful and isolated osteoarthritis of the ACJ who were treated by arthroscopic en bloc resection of the distal clavicle were included in the study. There were 10 males and 10 females with an average age of 56 years (range 42–70 years). The mean duration of followup was 6 years and 2 months (range 4–8 years 10 months). The results were evaluated using the University of California Los Angeles (UCLA) shoulder rating score.Results:The overall UCLA score was 13.7 preoperatively, which improved to 33.4 postoperatively. All subscores were improved significantly (P < 0.001). There were no specific complications at the latest followup.Conclusion:It is critical in this procedure to resect the distal clavicle evenly from superior to inferior in an en bloc fashion without any small bony remnants and to preserve the capsule and acromioclavicular ligament superoposteriorly. This arthroscopic procedure is a reliable and reproducible technique for painful osteoarthritis of the ACJ lesions in active patients engaged in overhead throwing sports and heavy labor.