Coracoclavicular ligament attachment regions of the Chinese population: a quantitative anatomic study

A Novel and Open Classification Emphasizing on Osteoligamentous Complex for Distal Clavicle Fractures

OBJECTIVE

Current X-ray-based classification methods cannot describe all distal clavicle fracture (DCF) patterns, especially the osteoligamentous injury pattern of DCFs. We aimed to develop a novel classification based on the osteoligamentous injury pattern of the DCFs and investigated its reliability.

METHODS

All DCFs from January 2017 to January 2022 were respectively screened and 45 cases (mean age 20-78; male 31, female 14) met the including criteria and were enrolled. Based on their Zanca view X-ray radiograph and three-dimensional CT construction images, we analyzed the osteoligamentous injury pattern of each case, particularly the acromioclavicular (AC) and coracoclavicular ligaments and their bone attachment. Then we developed a novel classification method, five types in total, sorting all DCFs according to their lesion manifestations of osteoligamentous complex. Also, we investigated the inter- and intra-observer reliability using kappa value.

RESULTS

A novel classification method for DCF was developed, manifesting the avulsion or rupture of conoid and trapezoid ligaments, and involvement of AC joint. Forty-five cases of DCFs were included in this study. Among them, 11 (24.4%) were Type 1 fracture, three (6.7%) cases were Type 2, six cases (13.3%) were Type 3, 21 (46.7%) were Type 4, four (8.9%) were Type 5. Kappa values for inter-observer agreement were 0.57 after first evaluation and 0.61 after second evaluation. Intra-observer agreement was 0.72 for experienced shoulder specialist and 0.63 for radiologist.

CONCLUSION

This new classification method is reliable to use, supplementary to current classification systems, and emphasizes on the osteoligamentous complex injury when opting for the treatment.

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.

Triple Endobutton technique for the treatment of Neer type II lateral clavicle fractures: 2-year findings

BACKGROUND

Although various kinds of operative procedures have been reported in the literature, there is still no undisputed gold standard technique for the treatment of Neer type II lateral clavicle fractures. This trauma is classified as a bone fracture, but it is primarily a ligamentous problem due to the instability it generates. This study analyzed the clinical and radiological results of treatment for Neer type II lateral clavicle fractures using the triple Endobutton (Smith & Nephew) technique in 20 patients with at least 2 years of follow-up.

METHODS

This study enrolled 20 patients with Neer type II distal clavicle fractures who underwent the triple Endobutton technique using 3 Endobuttons (1 with a closed loop and 2 without) and 3 No. 5 Ethibond sutures (Ethicon Inc.) from October 2017 to May 2020. Patients were assessed with clinical and radiological follow-up at 3, 6, 12, and 24 months postoperatively. Clinical assessments consisted of the visual analog scale and the Constant score. Radiological evaluation was achieved by measuring the coracoclavicular distance.

RESULTS

The mean follow-up was 35 ± 9 months (range, 24-55 months). The visual analog scale and Constant scores revealed significant improvements from 6 ± 1 (range, 4-8) and 42 ± 4 (range, 35-48) scores preoperatively to 1 ± 1 (range, 0-1) and 94 ± 2 (range, 90-98) scores at the final evaluation, respectively (P < .001). The coracoclavicular distance of the injured side was an average of 9 ± 1 mm (range, 7-12 mm) at the final follow-up radiograph which was not significantly different from that of the contralateral side (P = .75).

CONCLUSIONS

In this study, the triple Endobutton technique was a safe, reliable, and novel surgical technique that yielded good to excellent short-term clinical and radiological outcomes for the treatment of Neer type II distal clavicle fractures.

Comparing the Anatomical Landmarks Versus the Coracoid-Based Landmarks Techniques for Coracoclavicular Stabilization After High-Grade Acromioclavicular Injury: A Biomechanical Study

BACKGROUND

In acute high-grade acromioclavicular (AC) joint injuries, the aim of treatment is robust reduction and stabilization of the joint. The anatomical landmarks method is most commonly used for stabilization, but loss of reduction often occurs because of the suture tunnels.

PURPOSE/HYPOTHESIS

The purpose was to evaluate and compare the stability of coracoclavicular (CC) stabilization using the anatomical landmarks and coracoid-based landmarks techniques in treating a high-grade AC joint injury. It was hypothesized that stabilization using coracoid-based landmarks would provide better stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty fresh-frozen cadaveric shoulders (8 male and 2 female pairs) were randomized into 2 operative technique groups: 10 shoulders in the anatomical landmarks group and 10 shoulders in the coracoid-based landmarks group. The CC ligaments and AC capsule were cut at the midlevel, and CC stabilization and AC capsule repair were performed. For the anatomical landmarks technique, two 2.5-mm clavicular tunnels were created at 25 and 45 mm from the AC joint, while for the coracoid-based landmarks technique, two 2.5-mm clavicular tunnels were drilled using the medial and lateral borders of the coracoid base to choose the tunnel sites. Before injury creation and after stabilization, each shoulder underwent a loading force of 70 N in the superior and anteroposterior directions, and the displacement distance and stiffness were compared between the 2 techniques using the paired t test.

RESULTS

The mean difference in displacement before and after stabilization was higher in the anatomical landmarks technique than the coracoid-based landmarks technique (1.82 ± 3.52 vs -0.18 ± 4.78 mm in the superior direction and 7.47 ± 9.35 vs 1.76 ± 3.91 mm in the anteroposterior direction), but none of the differences in displacement or stiffness were statistically significant between the groups.

CONCLUSION

No significant biomechanical differences in displacement or stiffness were seen between the anatomical landmarks technique and the coracoid-based landmarks technique.

CLINICAL RELEVANCE

Either stabilization technique can be utilized for repair of the CC ligaments in an acute AC injury setting.

Computed Tomography‐Based Determination of the Optimal Locations of Bone Tunnels for Coracoclavicular Ligament Reconstruction

Objective

An agreement has not been reached on optimal locations of bone tunnels for coracoclavicular ligament (CCL) reconstruction for acromioclavicular joint dislocation (ACD). This study aims to identify the convergence point (cP) between the coracoid process and clavicle in the Chinese population to assist surgeons in reconstructing the CCL for ACD.

Methods

From 2014 to 2020, 483 CT scans of the shoulders of 270 male and 213 female patients (247 right and 236 left shoulders) were collected and studied retrospectively. By overlapping the images of the transverse plane of the coracoid process and the clavicle, points a and b, and the midpoint ab (cP) were determined. Then, a series of parameters through point cP in the transverse and sagittal planes were measured. In the transverse plane this included the distance from point cP to the tip of the coracoid process (cP‐cor),the distance between the medial and lateral margins of the coracoid process through point cP (Med‐lat cor), the distance from point cP to the acromioclavicular joint (cP‐ac), and the distance between the anteroposterior margin of the clavicle through point cP (Ap‐clav). In the sagittal plane, this included the craniocaudal segment of the coracoid process (Cc‐cor), and the craniocaudal segment of the clavicle (Cc‐clav). The sex and side differences of these measurements were also analyzed by two radiologists.

Results

Based on the following measurements, point cP was determined. For male patients, the cP‐cor was 28.02 ± 3.43 mm, Med‐lat cor was 22.78 ± 2.80 mm, Cc‐cor was 15.11 ± 2.13 mm, cP‐ac was 29.24 ± 3.84 mm, Ap‐clav was 18.27 ± 2.46 mm, and Cc‐clav was 10.09 ± 1.56 mm. For female patients, the cP‐cor was 25.20 ± 3.26 mm, Med‐lat cor was 20.21 ± 2.97 mm, Cc‐cor was 13.03 ± 1.77 mm, cP‐ac was 26.66 ± 3.45 mm, Ap‐clav was 16.10 ± 2.30 mm, and Cc‐clav was 8.91 ± 1.40 mm. All the measurements of female patients were lower than those of male patients (p < 0.01). Between sides, only cP‐ac of the left shoulders was significantly lower than those of the right shoulders (p < 0.05), with no significant differences in other parameters between sides (p > 0.05).

Conclusion

The results of this study identified the locations of bone tunnel‐cP in the coracoid process and clavicle for the CCL reconstruction in ACD. Moreover, the findings indicated that surgeons should be more cautious in operating on female patients and that the cP‐ac of left shoulders should be set lower than that of right shoulders.

Qualitative and Quantitative Anatomic Descriptions of the Coracoclavicular and Acromioclavicular Ligaments: A Systematic Review

Purpose

Methods

Results

Conclusions

Clinical Relevance

Truly anatomic coracoclavicular ligament reconstruction with 2 EndoButton devices for acute Rockwood type V acromioclavicular joint dislocations: 5-year findings

BACKGROUND

To date, mid-term clinical and radiologic outcomes of treatment for acute Rockwood type V acromioclavicular (AC) joint dislocations using 2 EndoButton devices (Smith & Nephew, Andover, MA, USA) have not been reported in the literature.

METHODS

We reviewed 25 patients (15 men and 10 women) with acute AC joint separations who were treated with truly anatomic coracoclavicular ligament reconstruction using 2 EndoButton devices between May 2013 and October 2015. Clinical assessments consisted of the visual analog scale score and the Constant score. Radiologic evaluation was achieved by measuring the coracoclavicular distance and AC distance. Previously, this same patient cohort was reviewed after 2 years of follow-up using similar methods.

RESULTS

All 25 patients were available for mid-term follow-up 5 years after the operation. The mean duration of follow-up was 76 ± 7 months (range, 66-90 months). Of the patients, 23 (92%) continued to be satisfied or very satisfied with the treatment results. The visual analog scale score and Constant score improved significantly when compared with the baseline scores (0 ± 0 and 96 ± 3, respectively, at 5-year follow-up vs. 5 ± 1 and 45 ± 6, respectively, postoperatively) and remained essentially unchanged when compared with the 2-year follow-up data (0 ± 0 and 96 ± 3, respectively, at 5-year follow-up vs. 0 ± 1 and 95 ± 3, respectively, at 2-year follow-up). On the 5-year radiographs, 3 patients (12%) demonstrated loss of reduction and 5 patients (20%) had calcifications noted. There was, however, no significant difference in clinical outcomes or patient satisfaction when comparing patients with radiographically abnormal findings vs. patients with anatomic reduction.

CONCLUSION

Truly anatomic coracoclavicular ligament reconstruction using 2 EndoButton devices results in satisfactory functional outcomes at 5 years postoperatively. In contrast to baseline, all cases improved significantly.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-02966-0.

Sex-Based Differences in Optimal Tunnel Placement for Acromioclavicular Joint Reconstruction

BACKGROUND

Tunnel placement is important for outcomes after acromioclavicular (AC) joint reconstruction, yet little has been written on sex-based differences in optimal tunnel positioning.

HYPOTHESIS

No sex-based or anatomic differences will be found in ideal tunnel position based on radiographic measurements.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

The records of 2382 patients were retrospectively examined for clavicle radiographs over a 20-year period. A random set of radiographs were reviewed until 200 radiographs from each sex met inclusion criteria per a priori power analysis. Anteroposterior clavicle radiographs were used to collect (1) length from lateral clavicle to lateral coracoid (LCLC), (2) length from lateral clavicle to medial coracoid (LCMC), (3) clavicle length (CL), and (4) clavicular depth at the midcoracoid (MCCD). The Student t test was used to compare differences between male and female patients. The Pearson correlation coefficient was used to measure linear correlations. Variables with a P < .1 were included in a multiple regression model.

RESULTS

The cohort included 200 men and 200 women. LCLC and LCMC were significantly greater for men than for women (P < .0001). Clavicle length was significantly correlated with LCLC (r = 0.63; P < .0001) and LCMC (r = 0.74; P < .0001). MCCD was significantly correlated with LCLC (r = 0.32; P < .0001) and LCMC (r = 0.43; P < .0001). The approximate placement for the trapezoid tunnel was found to be 22.1 mm in women and 26.6 mm in men. The approximate placement for the conoid tunnel was found to be 40 mm in women and 46.6 mm in men. The ratios (LCLC:CL and LCMC:CL) were also significantly different between female and male patients. The LCLC:CL was 0.144 in women and 0.154 in men (P < .0001). The LCMC:CL was 0.261 in women and 0.271 in men (P < .0006).

CONCLUSION

Significant sex-based differences are found in the position of the coracoid relative to the lateral edge of the clavicle. Coracoid position relative to the lateral edge of the clavicle is correlated with anatomic parameters, most strongly with clavicle length.

Predictors of safety margin for coracoid transfer: a cadaveric morphometric analysis

Background

The purpose of this study was to investigate the relationship between the bone length available for coracoid transfer without coracoclavicular ligament injury and the distance from the coracoid tip to the attachments of the coracoacromial ligament or pectoralis minor. We hypothesized that cadaver height and the soft tissue attachments on the coracoid process were predictive factors for sufficient bone length for coracoid transfer.

Methods

This study included 28 shoulders from Japanese cadavers: 19 male and 9 female. The distance from the coracoid tip to the distal attachment of the coracoclavicular ligament and the anterior and posterior margins of the coracoacromial ligament or pectoralis minor on the coracoid process were measured.

Results

The mean available length for coracoid transfer was 24.8 ± 3.4 mm. There was a significant difference in length between male and female subjects, being 26.0 ± 2.9 mm and 22.2 ± 3.0 mm, respectively (p = 0.004). High positive correlations were found between the length of the coracoid transfer and cadaver’s height (r = 0.48, p = 0.009) and the distance from the coracoid tip to the anterior coracoacromial ligament attachment (r = 0.63, p < 0.001). The receiver operating characteristic curve area under the curve for cadaver height was 0.72 while that for distance from coracoid tip to anterior coracoacromial ligament was 0.88 when predicted for a sufficient length for coracoid transfer > 25 mm.

Conclusions

Our findings will aid surgeons in preoperative planning and performing of osteotomy of the coracoid safely by predicting the available length of coracoid bone graft.

Anatomical study of the position and orientation of the coracoclavicular ligaments: Differences in bone tunnel position by gender

BACKGROUND

Reconstructing both coracoclavicular ligaments following acromioclavicular dislocation has recently been reported to restore the function of the acromioclavicular joint better than traditional procedures. Knowing the appropriate position and orientation of the bone tunnels and the potential risks of neurovascular injuries leads to safe reconstruction. We aimed to answer the following questions: what is the difference in the accurate clavicular bone tunnel positions (BTPs) during coracoclavicular ligament reconstruction between sex, and what are the potential risks for neurovascular injuries?

HYPOTHESIS

The BTPs differ by sex at the site of coracoclavicular ligament reconstruction.

PATIENTS AND METHODS

We introduced two Kirschner wires into 25 cadaver shoulders (17 male, 8 female), one through the insertion center of the trapezoid ligament and one through the conoid ligament, and measured the distance from the respective Kirschner wire insertion points to the bony landmarks of the clavicle and the oblique angle of each Kirschner wire. The shortest distance from the insertion point of each Kirschner wire to the suprascapular nerve and artery was also measured.

RESULTS

While the distance from the acromioclavicular joint to the respective Kirschner wire insertion points tended to be longer in males, the ratio of these insertion points to total clavicle length was constant. Other measurements for respective Kirschner wire insertions to the bony landmarks and neurovascular structures were comparable, as were abduction and retroversion angles. The distance from the suprascapular nerve to the insertion point of the conoid ligament at the coracoid process was 13.8±4.0mm, while the distance from the suprascapular artery was 7.1±3.3mm.

DISCUSSION

Appropriate position and orientation of the bone tunnels, and the ratio of the BTPs to the total clavicular length, aid surgeons in performing the reconstruction. The conoid ligament insertion on the coracoid was just proximal to the suprascapular artery, so surgeons should be careful with conoid insertion.

LEVEL OF EVIDENCE

V, cadaver study.

A prospective study of coracoclavicular ligament reconstruction with autogenous peroneus longus tendon for acromioclavicular joint dislocations

BACKGROUND

Anatomic coracoclavicular (CC) ligament reconstruction (ACCR) provides good outcomes for Rockwood type III and VI acromioclavicular (AC) joint dislocations. Various grafts have been used, but complications from graft harvesting are not uncommon. This study examined the clinical and radiographic outcomes of patients with AC joint dislocations repaired with the autogenous anterior half of the peroneus longus tendon (AHPLT) to achieve ACCR.

METHODS

Patients with a Rockwood type III to V AC joint dislocation and magnetic resonance imaging of the disruption of the CC ligaments, as well as the AC capsule, were prospectively recruited. Patients received ACCR using an autogenous AHPLT graft and were evaluated clinically and radiographically preoperatively and at 1, 3, 6, and 12 months postoperatively.

RESULTS

A total of 18 patients (mean age, 51 years) were prospectively recruited and received an autogenous AHPLT graft ACCR. Fifteen patients completed clinical and radiographic follow-up examinations at 12 months. The mean Constant score (CS) was 51 preoperatively and 93 at 12 months (P <.005). No significant difference was noted at 12 months between the CS of the injured and contralateral shoulder. The mean American Orthopedic Foot and Ankle Society score at 12 months was 99, and this was not different from the value at any other time point. Loss of reduction occurred in 10 patients (56%), and tunnel widening was observed in 9 (50%), but neither was significantly correlated with functional outcome.

CONCLUSION

Autogenous AHPLT appears to be a reliable tendon graft source for CC ligament reconstruction.

Comparison of hook plate with versus without double-tunnel coracoclavicular ligament reconstruction for repair of acute acromioclavicular joint dislocations: A prospective randomized controlled clinical trial

PURPOSE

This study was designed to compare the surgical outcomes of a hook plate with double-tunnel coracoclavicular (CC) ligament reconstruction by conjoined tendon transfer versus single hook plate surgery for the repair of acute type of Rockwood type III and V acromioclavicular (AC) joint dislocations.

METHODS

The study cohort included 62 patients with acute (within 6 weeks after trauma) Rockwood type III and V AC joint dislocations who underwent surgery from February 2012 to September 2015. The patients were randomly allocated to the ligament reconstruction group (LR group, n = 31) or the single hook plate group (HP group, n = 31). In both groups, reduction of the AC joint by hook plate and repair of the ruptured AC ligament with absorbable Vicryl sutures were performed homoplastically. The lateral half of the short tendon of the biceps brachii muscle and the lateral half of the flexor tendon were used to reconstruct the trapezoid and conoid ligaments, respectively. Differences in surgical duration, intraoperative blood loss, incision length, and total cost were compared between the two groups. Furthermore, the preoperative and postoperative visual analogue score (VAS), postoperative American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score (CMS), Karlsson score, complication rates, and patient satisfaction at the last follow-up were compared to evaluate the curative effects of the surgical treatments. Magnetic resonance imaging (MRI) after hook plate removal was used to evaluate the reconstructed ligaments and tendon-bone interface.

RESULTS

In total, 25 patients in the LR group and 26 in the HP group completed the follow-up. There were no statistically significant differences in age, sex, Rockwood type, placing time, total cost, and follow-up duration between the LR and HP groups (p > 0.05). However, as compared with the HP group, the surgical duration and incision length were longer in the LR group (92.08 ± 19.25 vs. 56.54 ± 21.29 min and 13.64 ± 0.90 vs. 6.65 ± 1.01 cm, respectively, p < 0.05). In addition, there was no significant difference in preoperative VAS scores, but the postoperative VAS score was lower in LR group than in the HP group (2.52 ± 1.19 vs. 4.12 ± 1.45, respectively, p < 0.05). Moreover, patients in LR group had a remarkable higher CMS and ASES score (89.56 ± 2.80 vs. 79.31 ± 4.97 and 92.60 ± 2.79 vs. 82.35 ± 3.44, respectively, p < 0.05). The overall excellent or good result rate, as evaluated by the Karlsson score, was 92.00% (23/25) and 50.00% (13/26), respectively (p < 0.05). MRI findings revealed good condition of the reconstructed ligaments and tendon-bone interface. The incidence of complications was lower and the satisfaction rate was higher in the LR group than in the HP group (1/25 vs. 16/26 and 23/25 vs. 14/26, respectively, p < 0.05).

CONCLUSIONS

The overall surgical effect of the use of a hook plate combined with double-tunnel CC ligament reconstruction is superior to single hook plate surgery for the repair of acute Rockwood type III and V AC joint dislocations.

Anatomic Coracoclavicular Ligament Reconstruction for the Treatment of Acute Acromioclavicular Joint Dislocation: Minimum 10-Year Follow-up

Background:

The long-term clinical and radiographic outcomes following coracoclavicular (CC) ligament reconstruction for the operative treatment of acute acromioclavicular (AC) joint dislocation remain uncertain. The purpose of the present study was to determine the long-term clinical and radiographic outcomes of CC ligament reconstruction and to identify risk factors for unfavorable outcomes.

Methods:

We reviewed 20 cases of AC joint dislocation in 19 patients (18 male and 1 female; mean age, 32.3 years) that were treated with single-bundle reconstruction. The mean duration of follow-up was 12.7 years. We measured the CC vertical distance (CCD) on the anteroposterior view and compared the affected and unaffected sides (CCD ratio). We divided the patients into those with a CCD ratio of <25% (Group 1) and those with a CCD ratio of ≥25% (Group 2). We radiographically investigated the clavicular tunnel anteroposterior (CTAP) angle, clavicular tunnel ratio, and coracoid tunnel orientation on the basis of the entry and exit points at the base of the coracoid. For the coracoid tunnel orientation, we compared center-center orientation and noncenter-center orientation.

Results:

Group 1 comprised 17 cases (85%), and Group 2 comprised 3 cases (15%). At the time of the latest follow-up, Group 1 had a significantly higher mean Constant score than Group 2 (98.2 compared with 90.7; p = 0.038). Of the 3 radiographic parameters, only the CTAP angle was significantly different between the 2 groups (p < 0.0001). Two (67%) of the 3 cases in Group 2 were associated with posterior AC joint displacement.

Conclusions:

CC ligament reconstruction for the treatment of acute AC joint dislocation resulted in successful long-term clinical and radiographic outcomes. It is important to decrease the CTAP angle and to ensure proper anatomic placement of the clavicular and coracoid tunnels at the time of surgery.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Anatomic study of coracoclavicular ligaments for reconstruction of acromioclavicular joint dislocations

BACKGROUND

There has been a trend to reconstruct the coracoclavicular (CC) ligaments anatomically for management of acromioclavicular (AC) joint dislocations.

PURPOSE

The aim of this study was to determine the location and orientation of the CC ligaments for anatomic reconstruction of the AC joint.

METHODS

The subjects were a total of 40 shoulders from 20 Chinese cadavers. Two K-wires were drilled through the insertion center of the conoid and trapezoid ligaments respectively. The distance from the center of the CC ligaments to the bone landmarks of the clavicle and the oblique angle of the two K-wires was measured respectively.

RESULTS

The distance from the center of the trapezoid ligament to the lateral end and the anterior border of the clavicle was 21.7 ± 1.1 mm and 6.4 ± 0.5 mm, respectively. The valgus angle and retroversion angle of the trapezoid ligament was 39.3°±0.9° and 6.0°±0.6°, respectively. The distance from the center of the conoid ligament to the lateral end and the posterior border of the clavicle was 36.6 ± 0.9 mm and 5.5 ± 0.4 mm, respectively. The valgus angle and retroversion angle of the conoid ligament was 6.6°±0.7° and 11.0°±0.9°, respectively.

CONCLUSIONS

These findings are important for the anatomic reconstruction of the AC joint dislocations, by predicting the location and orientation of the conoid and trapezoid ligaments accurately.

Midterm results of coracoclavicular stabilization with double augmentation for acute acromioclavicular dislocation

Introduction

Numerous techniques have been introduced for the treatment of acute acromioclavicular (AC) joint dislocation. We aim to report the midterm results of coracoclavicular (CC) stabilization with double augmentation for the acute AC joint dislocation.

Case description

Forty-three patients who underwent surgery for acute AC joint dislocation were followed up for an average of 59.6 months (range 40–97). The study composed of two treatment groups: group S, with 25 patients, in whom two suture anchors were used; and group B, with 18 patients, in whom a suture anchor and a double flip-button device were used, however the techniques in both groups are based on the same principle which is double augmentation. Postoperative evaluations were made retrospectively, clinically, and radiographically.

Discussion and Evaluation

At the last follow-up, the mean Constant score was 91.2 (range 74–100) and the UCLA scale was 31.4 (range 24–35). The overall ratio of the CC distance in the injured shoulder to that in the uninjured shoulder, expressed as a percentage, significantly decreased, to 93.4 ± 22.7 %, immediate postoperatively, and significantly increased, to 113.8 ± 23.4 %, at the final follow-up. Complete reduction of the AC joint was achieved in 34 patients (79.1 %), and 8 patients (18.6 %) exhibited a slight loss of reduction, although their functional outcomes were good.

Conclusions

The results of this study provide evidence that double augmentation is effective in the treatment of acute AC dislocation.

Level of evidence

Therapeutic study, case series, Level IV.

Biomechanical Comparison of Fracture Risk Created by 2 Different Clavicle Tunnel Preparations for Coracoclavicular Ligament Reconstruction

Background:

An anatomic reconstruction of coracoclavicular (CC) ligaments typically requires drilling tunnels in the clavicle. An increase in fracture complications has been associated with graft tunnel position. A method of drilling clavicle tunnels that would better re-create anatomic function of the CC ligaments without increasing fracture risk would be an improvement.

Purpose:

To evaluate the feasibility of a novel single anterior-to-posterior tunnel technique and compare the biomechanical properties to the 2-tunnel technique in CC ligament reconstruction. The hypothesis was that the single tunnel will yield similar loads to failure as the 2-tunnel technique and better reproduce the native anatomy of the conoid and trapezoid ligaments.

Study Design:

Controlled laboratory study.

Methods:

Eight fresh-frozen matched pairs of human clavicles underwent testing. In 1 specimen of the matched pair, 2 bone tunnels were created as previously described. In the other, a single tunnel was placed obliquely from anterior to posterior. The relative position of the tunnels in relation to the conoid tuberosity was recorded. Specimens were tested on a materials testing machine. The ultimate load to failure, linear stiffness, distance of the conoid tuberosity to the conoid tunnel exit point, and mode of failure were recorded.

Results:

The ultimate load to failure in the single-tunnel group and the 2-tunnel group was 457.2 ± 139.8 and 488.8 ± 170.6, respectively. There was no significant difference (P = .5). The linear stiffness in the single-tunnel group and the 2-tunnel group was 94.6 ± 31.3 and 79.8 ± 33.5, respectively. There was no significant difference (P = .2). The 2-tunnel group had a significantly longer average maximum distance from the conoid tuberosity to the conoid tunnel exit point than the single-tunnel group (6.0 ± 2.1 vs 0.8 ± 1.9 mm; P = .05). The single-tunnel group was consistently more anatomic with regard to its relationship to the conoid tuberosity than the 2-tunnel group.

Conclusion:

The single anterior-to-posterior clavicle tunnel had similar biomechanical properties to the 2-tunnel technique. However, the single-tunnel technique better reproduced the anatomic footprint of the conoid ligament. Utilizing this single-tunnel technique may yield an anatomic advantage that may also reduce the rate of complications caused by posterior wall blowout.

Clinical Relevance:

Acromioclavicular joint injuries are common in collision sports. Surgical management is often indicated to reconstruct the joint. This study assesses the feasibility of a novel surgical approach.

Coracoclavicular ligaments anatomical reconstruction: a feasibility study

BACKGROUND

This study assessed the feasibility of anatomical coracoclavicular (CC) ligaments reconstruction, using three-dimensional (3D) measurement and virtual drilling.

METHODS

One-hundred-and-five 3D shoulder models were constructed using SuperImage software, based on computed tomography (CT) scan data. For each model the attachment sites and footprint dimensions of the CC ligaments were defined and adjusted according to constant anatomical ratios and individual measurement results. Different drilling techniques and 3D measurements were carried out separately on each model.

RESULTS

The collinear drilling technique with one bundle was used to breach the clavicle and/or coracoid process bone cortex in 38 of 105 models (36.2%); the percentage with two bundles was 90.5% (95/105). No cortical breach was observed using the non-collinear drilling technique.

CONCLUSIONS

The non-collinear drilling technique provides the capability to prepare bony tunnels without any risk of cortical breach.