Ligamentous healing potential of the acromioclavicular ligament following acute anatomical reconstruction.

BACKGROUND: Horizontal instability following acute acromioclavicular joint (ACJ) reconstruction still occurs with a high prevalence. Although the human acromioclavicular ligament complex (ACLC) represents the major horizontal ACJ stabilizer, experimental studies on healing characteristics are lacking. Therefore, the purpose of this histological study was to investigate the healing potential of the ACLC following acute anatomical reconstruction METHODS: In this prospective clinical-experimental study, 28 ACLC biopsies were performed in patients with complete ACJ dislocations (Rockwood type 4 or 5) during acute hook plate stabilization (IG: implantation group; n = 14) and hook plate removal (EG: explantation group; n = 14). Histological analyses included Giemsa staining, polarized light microscopy and immunostaining against CD68, αSMA and collagen type I and type III. Histomorphological evaluation entailed cell counts, collagen expression score, ligament tissue maturity index (LTMI) and descriptive analysis of specific ligamentous structures. Statistics consisted of nonparametric Mann-Whitney U tests and a level of significance of P < .05. RESULTS: Total cell counts (cells/mm2 1491 ± 296 vs. 635 ± 430; P < 0.001) and collagen III expression (3.22 ± 0.22 vs. 1.78 ± 0.41; P < 0.001) were higher in EG compared to IG. Inversely αSMA + (11 ± 9 vs. 179 ± 186; P < 0.001) and CD68 + cell counts (56 ± 20 vs. 100 ± 57; P 0.009) were significantly lower in the EG. The EG revealed a comparable reorientation of ligamentous structures. Consistently, ACLC samples of the EG (21.6 ± 2.4) displayed a high total but differently composed LTMI score (IG: 24.5 ± 1.2; P < 0.001). CONCLUSIONS: This experimental study proved the ligamentous healing potential of the human ACLC following acute anatomical reconstruction. Histomorphologically, the ACLC reliably showed a ligamentous state of healing at a mean of about 12 weeks after surgery. However, processes of ligamentous remodeling were still evident. These experimental findings support recent clinical data showing superior horizontal ACJ stability with additional AC stabilization in the context of acute ACJ reconstruction. Though, prospective clinical and biomechanical studies are warranted to evaluate influencing factors on ACLC healing and potential impacts of acute ACLC repair on clinical outcome. STUDY TYPE: Controlled Laboratory Study.

Anatomic reconstruction of the coracoclavicular and acromioclavicular ligaments with semitendinosus tendon graft for the treatment of chronic acromioclavicular joint dislocation provides good clinical and radiological results.

PURPOSE: To evaluate clinical and radiographic outcomes of anatomical reconstruction of the coracoclavicular and acromioclavicular ligaments with single-strand semitendinosus tendon graft for the treatment of chronic acromioclavicular joint dislocation. METHODS: Patients affected by chronic type III-V acromioclavicular joint dislocations were included. Exclusion criteria were: age under 18 years, concomitant rotator cuff tears, previous surgery to the same shoulder, degenerative changes of the glenohumeral joint, infections, neurologic diseases, patients with a previous history of ligament reconstruction procedures that had required harvesting of the semitendinosus tendon from the ipsilateral or contralateral knee. All patients underwent the same surgical technique and rehabilitation. Primary outcome was the normalized Constant score. Secondary outcomes were: DASH score, radiographic evaluation of loss of reduction and acromioclavicular joint osteoarthritis. RESULTS: Thirty patients with a mean age of 28.9 ± 8.3 years were included. Mean time to surgery was 12.8 ± 10 months. Mean follow-up was 28.1 ± 2.4 months (range: 24-32). Comparison between pre- and postoperative functional scores showed significant clinical improvement (p < 0.001). Time to surgery was independently associated with a poorer Constant score (p < 0.0001). On radiographs, 4 patients (13.3%) showed asymptomatic partial loss of reduction. CONCLUSION: Anatomic reconstruction of coracoclavicular and acromioclavicular ligaments using a semitendinosus tendon graft for the treatment of chronic acromioclavicular joint dislocation provided good clinical and radiological results at minimum 2-year follow-up. LEVEL OF EVIDENCE: Level III.

Biologic and synthetic ligament reconstructions achieve better functional scores compared to osteosynthesis in the treatment of acute acromioclavicular joint dislocation.

PURPOSE: To systematically review the outcomes of surgical treatments of acute acromioclavicular joint dislocation. METHODS: Studies were identified by electronic databases (Ovid, PubMed). All studies reporting functional and radiological outcomes of surgical treatments of acute acromioclavicular joint dislocations were included. Following data were extracted: authors and year, study design, level of evidence, number of patients, age, classification of acromioclavicular joint dislocation, time to surgery, surgical technique, follow-up, clinical and imaging outcomes, complications, and failures. Descriptive statistics was used, when a data pooling was not possible. Comparable outcomes were pooled to generate summary outcomes reported as frequency-weighted values. Quality appraisal was assessed through the MINORS checklist. RESULTS: One hundred and thirty-three studies were included for a total of 4473 shoulders. Mean age of participants was 36.9 years. Mean follow-up was 42.06 months. Arthroscopy showed better ASES (p < 0.0001) and lower VAS pain score (p = 0.0249) compared to an open approach. Biologic and synthetic reconstructions demonstrated better results over osteosynthesis techniques. Biologic techniques showed overall better Constant (p = 0.0001) and DASH (p = 0.0215) scores, while synthetic reconstruction showed better UCLA score (p = 0.0001). Among suture buttons, triple button showed overall better results in Constant (p = 0.0001) and VAS (p = 0.0001) scores, while better results in DASH score (p = 0.0003) were achieved by 2 double button techniques. Overall, the level of evidence was low. CONCLUSION: Biological and synthetic reconstructions achieved better functional scores compared to osteosynthesis. Among suture buttons, the triple button showed better functional performance. LEVEL OF EVIDENCE: IV.

Repair of the entire superior acromioclavicular ligament complex best restores posterior translation and rotational stability.

PURPOSE: The acromioclavicular ligament complex (ACLC) is the primary stabilizer against horizontal translation with the superior ACLC providing the main contribution. The purpose of this study was to evaluate the specific regional contributions in the superior half of ACLC, where the surgeon can easily access and repair or reconstruct, for posterior translational and rotational stability. METHODS: The superior half of ACLC was divided into three regions; Region A (0°-60°): an anterior 1/3 region of the superior half of ACLC, Region B (60°-120°): a superior 1/3 region of the superior half of ACLC, and Region C (120°-180°): a posterior 1/3 region of the superior half of ACLC. Fifteen fresh-frozen cadaveric shoulders were used. Biomechanical testing was performed to evaluate the resistance force against passive posterior translation (10 mm) and the resistance torque against passive posterior rotation (20°) during the following the four conditions. (1) Stability was tested on all specimens in their intact condition (n = 15). (2) The ACLC was dissected and stability was tested (n = 15). (3) Specimens were randomly divided into three groups by regions of suturing. Stability was tested after suturing Region A, Region B, or Region C (n = 5 per group). (4) Stability was tested after suturing additional regions: Region A + B (0°-120°), Region B + C (60°-180°), or Region A + C (0°-60°, 120°-180°, n = 5 per group). RESULTS: The translational force increased after suturing Region A when compared with dissected ACLC (P = 0.025). The force after suturing Region A + B was significantly higher compared to the dissected ACLC (P < 0.001). The rotational torque increased after suturing Region A or Region B compared with dissected ACLC (P = 0.020, P = 0.045, respectively). The torque after suturing the Region A + C was significantly higher compared to the dissected ACLC (P < 0.001). CONCLUSION: The combined Region A + B contributed more to posterior translational stability than Region B + C or Region A + C. In contrast, combined Region A + C contributed more to posterior rotational stability than Region A + B or Region B + C. Based on these findings, surgical techniques restoring the entire superior ACLC are recommended to address both posterior translational and rotational stability of the AC joint.

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

BACKGROUND: Horizontal 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. METHODS: This 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. RESULTS: All 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. CONCLUSIONS: Acute 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.

Surgical Pearls and Pitfalls for Anatomic Acromioclavicular/Coracoclavicular Ligament Reconstruction.

Injuries to the acromioclavicular (AC) joint are common shoulder injuries in contact/collision athletes. There are a number of different surgical options that can be used to treat these injuries. The majority of these injuries can be treated nonoperatively with an early return to play for type I and II injuries. Surgical intervention and AC/CC (coracoclavicular) ligament reconstruction have excellent postoperative outcomes if complications can be avoided. This review will focus on the pearls and pitfalls for anatomic AC and CC ligament reconstruction for high-grade AC joint injuries.

Acromioclavicular reconstruction techniques after acromioclavicular joint injuries: A systematic review of biomechanical studies.

BACKGROUND: Residual horizontal instability after surgical treatment for acromioclavicular joint injuries is seen as a potential cause of suboptimal clinical outcomes. Biomechanical studies have demonstrated that the acromioclavicular capsule/ligaments are the primary restraints for anteroposterior translation. However, limited studies have addressed the biomechanics of a reconstruction of the acromioclavicular capsule/ligaments. The aim of this systematic review was to evaluate the biomechanical role of acromioclavicular capsule/ligament reconstruction techniques after an acromioclavicular joint injury. METHODS: A search was carried out on the databases Medline and EMBASE, and was conducted according to the PRISMA guidelines. Biomechanical studies addressing horizontal and vertical displacement or joint stiffness after reconstructing the acromioclavicular capsule/ligament with or without coracoclavicular ligament reconstruction, were included. FINDINGS: Nineteen studies were included in this review after screening and eligibility assessment. Five of them investigated different sole acromioclavicular capsule/ligament reconstruction techniques. In 10 studies, a sole coracoclavicular ligament reconstruction was compared to a coracoclavicular ligament reconstruction with additional acromioclavicular capsule/ligament reconstruction. The remaining 4 studies compared different acromioclavicular capsule/ligament with coracoclavicular reconstruction techniques with each other. INTERPRETATION: Several testing protocols to evaluate acromioclavicular capsule/ligament reconstruction have been described and can make it difficult to compare the results of the different studies. Acromioclavicular capsule/ligament reconstruction may provide increased anteroposterior and rotational stability but an optimal reconstruction technique, which mimics all biomechanical characteristics of the native joint is not yet available.

The stress and strain pattern in the ligaments of the acromioclavicular joint using a quasi-static model.

BACKGROUND: The precise role of the acromioclavicular and coracoclavicular ligaments during shoulder motion is unclear. We evaluate changes in the stress-strain distribution of the acromioclavicular joint's ligaments during different shoulder passive motion positions. METHODS: A 3D acromioclavicular joint model was reconstructed. A constitutive hyperelastic model was used for the ligaments. The kinematics of the shoulder girdle was taken to simulate shoulder abduction (Motion 1) and horizontal adduction (Motion 2). A computer-generated quasi-static and non-linear finite element model was used to predict the 3D stress-strain distribution pattern of the acromioclavicular ligament and the coracoclavicular ligament complex. FINDINGS: In motion 1, from 20 to 90° the peak von Mises stress was found in the conoid (4.14 MPa) and the anteroinferior bundle (2.46 MPa), while from 90 to 120° it was found in the conoid and the trapezoid. However, there were no significant differences between the mean stress values between anteroinferior bundle and trapezoid throughout the motion (p = 0.98). In Motion 2, from 20 to 80° the maximum equivalent elastic strain was found in the anteroinferior bundle (0.68 mm/mm) and the conoid (0.57 mm/mm), while from 80 to 100° it was higher in the conoid (0.88 mm/mm) than in the anteroinferior bundle (0.77 mm/mm). INTERPRETATION: The coracoclavicular ligament complex demonstrated a high stress-strain concentration during simulated passive shoulder abduction. Additionally, it was shown that the acromioclavicular ligament plays an important role in joint restraint during passive horizontal adduction, changing the primary role with the trapezoid and conoid at different motion intervals.

Differences between Coracoclavicular, Acromioclavicular, or Combined Reconstruction Techniques on the Kinematics of the Shoulder Girdle.

BACKGROUND: Although the coracoclavicular (CC) ligaments are classically reconstructed after acromioclavicular (AC) joint injuries, biomechanical studies over the past decade have indicated the importance of an additional reconstruction of the AC ligaments. To date, no kinematic study has investigated the kinematic differences between these reconstruction strategies. PURPOSE: To evaluate the restoration of shoulder motion after an AC injury using a CC ligament, an AC ligament, or a combined reconstruction technique. STUDY DESIGN: Controlled laboratory study. METHODS: After creating a Rockwood grade V lesion in 14 cadaveric shoulders, the AC joint injury was treated with either a CC ligament reconstruction using a suspension device, an in situ AC ligament reconstruction using 2 coupled soft tissue anchors, or a combination of these 2 techniques. Joint motions were registered during humerothoracic elevation in the coronal plane and protraction in the intact shoulder in a Rockwood V lesion and after the 3 reconstruction strategies. An optical navigation system measured 3-dimensional rotation in the sternoclavicular and scapulothoracic joints, and both rotation and translation were analyzed in the AC joint. RESULTS: In the sternoclavicular joint, the CC and combined reconstruction techniques adequately restored clavicular axial rotation, while the AC reconstruction technique showed a better correction of clavicular elevation. Scapulothoracic joint rotations were best restored by reconstructing the AC ligaments. In the AC joint, the relative tilting position and the lateral rotation of the scapula compared with the clavicle were best restored by the suspension device and combined reconstruction. The AC ligament reconstruction technique demonstrated a better restoration of the relative protracted position and resulted in a better correction of the translation of the scapula relative to the clavicle. CONCLUSION: This study illustrates that there are kinematic differences between AC, CC, or combined ligament reconstruction strategies. Although each technique was able to restore different elements of the joint kinematics, none of the strategies completely restored the shoulder girdle to its preinjured state. CLINICAL RELEVANCE: Humerothoracic movements after Rockwood V lesions are best restored using the CC reconstruction technique, and scapulothoracic movements are best restored using the AC ligament reconstruction technique.

The "Chiang Mai Lean Forward" Radiographic View for Acromioclavicular Joint Injuries: A Cadaveric Study.

Background: Operative treatment is suggested for unstable type 3 acromioclavicular (AC) joint injuries; however, there is no clear consensus regarding the definition of an unstable type 3 injury. We propose a new radiographic method, the "Chiang Mai lean forward" view, to verify horizontal displacement in an unstable AC joint injury. Hypothesis: A radiograph taken with the torso leaning forward would allow the detection of a higher proportion of AC joint injuries. Study Design: Descriptive laboratory study. Methods: A total of 20 shoulders from 10 fresh whole-body cadaveric specimens (mean age, 68.8 years) were tested at 3 different torso leaning angles (30°, 45°, and 60°) to determine the best position for projecting the x-ray beam. The shoulders were dissected sequentially starting with the AC ligament (stage 1), then additional sectioning of the partial coracoclavicular (CC) ligament with either the trapezoid ligament cut first (stage 2A) or the conoid ligament cut first (stage 2B), and finally complete sectioning of the CC ligament (stage 3). Radiography was performed after each stage to evaluate the degree of displacement of the anterior border of the acromion relative to the anterior border of the clavicle. Paired t tests were used to compare the degree of displacement at each stage to that of the shoulder before cutting. Results: Leaning at an angle of 30° provided better visualization of the AC joint in the "Chiang Mai lean forward" view. Compared with the intact condition, complete isolated cutting of the AC ligament produced 5.21 mm of horizontal displacement of the AC joint (P < .0001), complete tearing of the AC ligament and partial cutting of the CC ligament resulted in a displacement of <12 mm (7.91 mm at stage 2A [P = .0003] and 8.10 mm at stage 2B [P = .0013]), and complete tearing of both the AC and the CC ligaments resulted in a displacement of 26.37 mm (P < .0001). Conclusion: The "Chiang Mai lean forward" radiographic view is a potentially useful tool for determining the degree of the injury and the stability of the AC joint.

Anteroinferior bundle of the acromioclavicular ligament plays a substantial role in the joint function during shoulder elevation and horizontal adduction: a finite element model.

BACKGROUND: Postoperative acromioclavicular (AC) ligament deficiency has been identified as a common cause of failure after isolated coracoclavicular reconstruction. The two-bundle arrangement of the acromioclavicular ligament has recently been reported in histological and anatomical research. In addition, a clear structural advantage of the superoposterior bundle (SPB) over the less consistent anteroinferior bundle (AIB) was also found. However, the current understanding of the function of the acromioclavicular ligament in joint stability is based on uniaxial bone loading experiments and sequential ligament sectioning. Consequently, these rigid biomechanics models do not reproduce the coupled physiological kinematics, neither in the normal joint nor in the postoperative condition. Therefore, our goal was to build a quasi-static finite element model to study the function of the acromioclavicular ligament based on its biomechanical performance patterns using the benefits of computational models. METHODS: A three-dimensional bone model is reconstructed using images from a healthy shoulder. The ligament structures were modeled according to the architecture and dimensions of the bone. The kinematics conditions for the shoulder girdle were determined after the osseous axes aligned to simulate the shoulder elevation in the coronal plane and horizontal adduction. Three patterns evaluated ligament function. The peak von Mises stress values were recorded using a clock model that identified the stress distribution. In addition, the variation in length and displacement of the ligament during shoulder motion were compared using a two-tailed hypotheses test. P values < 0.01 were considered statistically significant. RESULTS: The peak von Mises stress was consistently observed in the AIB at 2:30 in coronal elevation (4.06 MPa) and horizontal adduction (2.32 MPa). Except in the position 2:00, statistically significant higher deformations were identified in the two bundles during shoulder elevation. The highest ligament displacement was observed on the Y- and Z-axes. CONCLUSIONS: The AIB has the primary role in restricting the acromioclavicular joint during shoulder motion, even though the two bundles of the AC ligament have a complementary mode of action. During horizontal adduction, the SPB appears to prevent anterior and superior translation.

The Role of the Acromioclavicular Ligament in Acromioclavicular Joint Stability: A Cadaveric Biomechanical Study.

BACKGROUND: Acromioclavicular (AC) joint dislocation is evaluated using the radiologically based Rockwood classification. The relationship between ligamentous injury and radiological assessment is still controversial. PURPOSE/HYPOTHESIS: To investigate how the AC ligament and trapezoid ligament biomechanically contribute to the stability of the AC joint using cadaveric specimens. The hypothesis was that isolated sectioning of the AC ligament would result in increased instability in the superior direction and that displacement >50% of the AC joint would occur. STUDY DESIGN: Controlled laboratory study. METHODS: Six shoulders from 6 fresh-frozen cadavers were used in this study. Both the scapula and sternum were solidly fixed on a customized wooden jig with an external fixator. We simulated distal clavicular dislocation with sequential sectioning of the AC and coracoclavicular (CC) ligaments. Sectioning stages were defined as follows: stage 0, the AC ligament, CC ligament, and AC joint capsule were left intact; stage 1, the anteroinferior bundle of the AC ligament, joint capsule, and disk were sectioned; stage 2, the superoposterior bundle of the AC ligament was sectioned; and stage 3, the trapezoid ligament was sectioned. The distal clavicle was loaded with 70 N in the superior and posterior directions, and the magnitudes of displacement were measured. RESULTS: The amounts of superior displacement averaged 3.7 mm (stage 0), 3.8 mm (stage 1), 8.3 mm (stage 2), and 9.5 mm (stage 3). Superior displacement >50% of the AC joint was observed in stage 2 (4/6; 67%) and stage 3 (6/6; 100%). The magnitudes of posterior displacement were 3.7 mm (stage 0), 3.7 mm (stage 1), 5.6 mm (stage 2), and 9.8 mm (stage 3). Posterior displacement >50% of the AC joint was observed in stage 3 (1/6; 17%). CONCLUSION: We found that the AC ligaments contribute significantly to AC joint stability, and superior displacement >50% of the AC joint can occur with AC ligament tears alone. CLINICAL RELEVANCE: The AC ligament plays an important role not only in horizontal stability but also in vertical stability of the AC joint.

The Orientation and Variation of the Acromioclavicular Ligament: An Anatomic Study.

BACKGROUND: Several biomechanical studies have shown that the acromioclavicular (AC) ligament prevents posterior translation of the clavicle in the horizontal plane. In anatomy textbooks, however, the AC ligament is illustrated as running straight across the AC joint surface. HYPOTHESIS: The AC ligament does not run straight across the joint surface, and the configuration of the AC ligament may vary. STUDY DESIGN: Descriptive laboratory study. METHODS: We used 16 pairs of shoulder girdles in this study. After identifying the AC ligament, we macroscopically investigated the orientation and attachment of the ligament and measured the angle between the ligament and the line perpendicular to the AC joint surface by using a digital goniometer. In addition, the AC joint inclination angle was measured, and the Spearman rank correlation coefficient between the joint inclination and the ligament angle was calculated. Finally, we sought to classify the AC ligament based on its configuration. Of the 16 pairs of specimens, 3 pairs of shoulders were histologically examined. RESULTS: The AC ligament was divided into 2 parts: a bundle at the superoposterior (SP) part and a bundle at the anteroinferior (AI) part of the joint. The well-developed SP bundle was consistent and ran obliquely at an average ± SD 30° ± 6° in relation to the AC joint surface, from the anterior part of the acromion to the posterior part of the distal clavicle. The joint inclination was 70° ± 12°, and a negative moderate correlation was found between the joint inclination and the ligament angle (P = .02, r = -0.46). In comparison, the AI bundle was thin and narrow, and it could be categorized into 3 types according to its various configurations. CONCLUSION: The AC ligament could be separated into the SP bundle and the AI bundle. The SP bundle ran posteriorly toward the distal clavicle from the acromion at an average angle of 30° to the joint surface. CLINICAL RELEVANCE: Anatomic reconstruction, based on the current findings in combination with findings regarding the coracoclavicular ligament, could facilitate improved outcome in the treatment of AC joint disruption.

Functional anatomy and vertical biomechanics of the acromioclavicular joint / 中华创伤骨科杂志

Objective To determine the role of acromioclavicular ligament in maintaining the stability of acromioclavicular joint.Methods In 12 cadaveric specimens of normal shoulder joint which had been routinely treated by formalin,the coracoclavicular ligaments (trapezium and conical ligaments) were dissected and exposed after soft tissue was removed from the surface.The distribution of the insertion and starting points,appearance and attachment area of the trapezium and conical ligaments were observed.The lengths of the 2 ligaments,the coronal and sagittal lengths of the clavicular attachment area,the distances from the most lateral point to the distal end of the clavicle,and the angles at the coronal and sagittal positions of the 2 ligaments were measured.Subsequently,the 12 cadaveric specimens were randomly divided into 4 groups (n =3).Group A retained the intact acromioclavicular ligament,group B the intact coracoclavicular ligament,group C the intact trapezium ligament and group D the intact conical ligament.In an electronic machine for versatile mechanical tests,a 100 mm/min load speed was applied for destructive static stretching of the ligament specimens in the vertical direction.The load-displacement curves were recorded and drawn by a computer in connection with the biomechanical testing machine.The rupture strengths of the 4 ligaments were recorded.Results The average lengths of the conical and trapezium ligaments were 10.6 mm and 12.5 mm,respectively.The coronal and sagittal lengths of the clavicular attachment area of the conical ligament averaged 13.4 mm and 5.8 mm,respectively.The coronal and sagittal lengths of the clavicular attachment area of the trapezium ligament averaged 14.2 mm and 8.7 mm,respectively.The distances from the most lateral points of the conical and trapezium ligaments to the distal clavicle averaged 35.5 mm and 23.6 mm,respectively.The average angles at the coronal and sagittal positions were 6.2° and 11.3° for the conical ligament and 38.7°and 6.9° for the trapezium ligament,respectively.The average tensile force was 201.3 ± 1.9 N for the acromioclavicular ligament rupture,374.6 ± 1.4 N for the coracoclavicular ligament rupture,192.3 ±4.3 N for the trapezium ligament rupture,and 345.7 ± 1.1 N for the conical ligament rupture.Conclusions The roles and contributions of the conical,trapezium and acromioclavicular ligaments are different in maintaining the stability of the acromioclavicular joint.In anatomical reconstruction of the acromioclavicular joint,it is more important to reconstruct the conical ligament and to repair the acromioclavicular ligament simultaneously as much as possible.

Functional anatomy and vertical biomechanics of the acromioclavicular joint / 中华创伤骨科杂志

Objective@#To determine the role of acromioclavicular ligament in maintaining the stability of acromioclavicular joint.@*Methods@#In 12 cadaveric specimens of normal shoulder joint which had been routinely treated by formalin, the coracoclavicular ligaments (trapezium and conical ligaments) were dissected and exposed after soft tissue was removed from the surface. The distribution of the insertion and starting points, appearance and attachment area of the trapezium and conical ligaments were observed. The lengths of the 2 ligaments, the coronal and sagittal lengths of the clavicular attachment area, the distances from the most lateral point to the distal end of the clavicle, and the angles at the coronal and sagittal positions of the 2 ligaments were measured. Subsequently, the 12 cadaveric specimens were randomly divided into 4 groups (n=3). Group A retained the intact acromioclavicular ligament, group B the intact coracoclavicular ligament, group C the intact trapezium ligament and group D the intact conical ligament. In an electronic machine for versatile mechanical tests, a 100 mm/min load speed was applied for destructive static stretching of the ligament specimens in the vertical direction. The load-displacement curves were recorded and drawn by a computer in connection with the biomechanical testing machine. The rupture strengths of the 4 ligaments were recorded.@*Results@#The average lengths of the conical and trapezium ligaments were 10.6 mm and 12.5 mm, respectively. The coronal and sagittal lengths of the clavicular attachment area of the conical ligament averaged 13.4 mm and 5.8 mm, respectively. The coronal and sagittal lengths of the clavicular attachment area of the trapezium ligament averaged 14.2 mm and 8.7 mm, respectively. The distances from the most lateral points of the conical and trapezium ligaments to the distal clavicle averaged 35.5 mm and 23.6 mm, respectively. The average angles at the coronal and sagittal positions were 6.2° and 11.3° for the conical ligament and 38.7°and 6.9° for the trapezium ligament, respectively. The average tensile force was 201.3±1.9 N for the acromioclavicular ligament rupture, 374.6±1.4 N for the coracoclavicular ligament rupture, 192.3±4.3 N for the trapezium ligament rupture, and 345.7±1.1 N for the conical ligament rupture.@*Conclusions@#The roles and contributions of the conical, trapezium and acromioclavicular ligaments are different in maintaining the stability of the acromioclavicular joint. In anatomical reconstruction of the acromioclavicular joint, it is more important to reconstruct the conical ligament and to repair the acromioclavicular ligament simultaneously as much as possible.

Plate-cable system for acromioclavicular joint dislocation based on the principle of anchor / 局解手术学杂志

Objective To investigate the biomechanical characteristics of the acromioclavicular joint,put forward the treatment of acromioclavicular joint dislocation based on the principle of anchor and apply to clinic.Methods From August 2011 to March 2015,24 patients with the acromioclavicular joint dislocation in department of orthopedics of Chinese Medicine Hospital of Changshu were divided into the treatment group and the control group,with 12 cases in each group.The treatment group were treated by vertical suspension buttons steel cable system based on principle of anchor,while the control group were treated by the hook plate technology.The clinical results of the two groups were evaluated by Karlsson score system.Results All the patients were followed up for 6 to 12 months.In terms of the curative effect in the treatment group,there were 11 cases of excellent and 1 case of good,with the excellent and good rate of 100%,and no complication occured.In the control group,there were 7 cases of excellent and 3 case of good,with the excellent and good rate of 83.3%.And there was 1 case of subacromial osteolysis.Conclusion To treat acromioclavicular joint dislocation above Rockwood Ⅲ with vertical suspension buttons steel cable system based on principle of anchor may be an ideal treatment method.

Treatment of patients with acromioclavicular joint injuries (Rockwood II-VI) with modeled Kirschner wire and cortical screw

Objective: To propose an original method of surgical treatment for the acromial extremity of the clavicle rupture (Rockwood II-VI) with modeled Kirschner wire and cortical screw. Methods: Anatomical study and a test method were applied to 43 cadavers of both sexes. During the period between 2000 and 2013, 34 patients of both sexes were operated upon using the new method. In the comparison group (n = 120), the fixation of the acromial extremity of the clavicle rupture was performed with hamate plate, Lee hook and Kirschner wires. Results: Its application allows, according to the evaluation scale of Constant and Murley (1987), 10% more preservation of the function of the shoulder compared with traditional methods of surgical treatment, and shortens the required hospital treatment and temporary disability periods. Conclusions: It is shown that the proposed author's method combines low invasiveness, minimum dimensions of the construction and low-cost treatment.

Treatment of patients with acromioclavicular joint injuries (Rockwood II-VI) with modeled Kirschner wire and cortical screw

Objective:To propose an original method of surgical treatment for the acromial extremity of the clavicle rupture (Rockwood II-VI) with modeled Kirschner wire and cortical screw. Methods:Anatomical study and a test method were applied to 43 cadavers of both sexes. During the period between 2000 and 2013, 34 patients of both sexes were operated upon using the new method. In the comparison group (n=120), the fixation of the acromial extremity of the clavicle rupture was performed with hamate plate, Lee hook and Kirschner wires. Results:Its application allows, according to the evaluation scale of Constant and Murley (1987), 10%more preservation of the function of the shoulder compared with traditional methods of surgical treatment, and shortens the required hospital treatment and temporary disability periods. Conclusions: It is shown that the proposed author’s method combines low invasiveness, minimum dimensions of the construction and low-cost treatment.

Treatment of double loop double button plate fixation on patients with complete acromioclavicular joint dislocation / 中国综合临床

Objective To investigate the application of the double loop double button plate fixation on treatment of patients with complete acromioclavicular joint dislocation.Methods Twenty-six cases with Rockwood type Ⅲ complete acromioclavicular joint dislocation were selected as our subjects who hospitalized from Jan.2011 to Jul.2013 and underwent using dual loop button plate technology of double fixation and reconstruction of coracoclavicular ligament fixation.There were 19 males and 7 females.Their age ranged from 18 to 62 years old and average was 30.2 years old.Adopt Lazzcano standard score was used to evaluate the shoulder joint function.Results X-ray examination showed the acromioclavicular joint of all patients were fixed in right place.Shoulder function was back to normal after 1 to 2 months and no pain or mild pain were showed in some patients.Twenty-four cases were followed up for 6-24 months,and the average followed up periods was 18.2 months.According to Lazzcano standard score to assess the function of shoulder join.Twenty cases were excellent and 4 cases were in good.The excellent and good rate was 100％.Conclusion Dual loop button plate technique is proved to be a good approach in the treatment of complete acromioclavicular joint dislocation with small trauma,stable fixation.Meanwhile patients can perform early functional exercise and no recurrent dislocation without the need of internal re-fixation.

Tension Band Wiring for Distal Clavicle Fracture: Radiologic Analysis and Clinical Outcome

PURPOSE: The purpose of this study is to evaluate the radiologic and clinical outcomes after tension band wire fixation of Neer type II distal clavicle fractures. MATERIALS AND METHODS: Twenty-six patients with Neer type II distal clavicle fractures who underwent tension band wire fixation from March 2002 to May 2011 were included in the study. Fifteen cases were classified as Neer type IIa and 11 cases as type IIb. The postoperative mean follow-up period was 14.3 months. Clinical and radiologic evaluation was performed at two weeks, six weeks, three months, six months, and 12 months postoperatively. RESULTS: Bony union on X-rays was observed at an average of 11.7 weeks (range 8-20 weeks) postoperatively. The overall visual analogue scale score for pain was 1.23+/-2.75 postoperatively. The overall postoperative University of California at Los Angeles score increased to 33.5+/-2.15 from the preoperative score of 21.6+/-1.91 (p<0.05). CONCLUSION: Among various methods of treatment for Neer type II distal clavicle fracture, K-wire and tension band fixation was used and relatively satisfactory radiological and clinical results were obtained. This surgical method yields excellent clinical results, owing to its relatively easy technique, fewer complications, and allowance of early rehabilitation.