Biomechanical evaluation of effect of coracoid tunnel placement on load to failure of fixation during repair of acromioclavicular joint dislocations

Coracoclavicular and acromioclavicular ligament reconstruction with a double-bundle semitendinosus autograft and cortical buttons for chronic acromioclavicular joint dislocations: clinical and imaging outcomes

BACKGROUND

There are few clinical and radiographic studies of coracoclavicular (CC) ligament reconstruction in chronic acromioclavicular (AC) joint dislocation. Additionally, reported AC joint reduction rates vary.

HYPOTHESIS

Arthroscopically assisted double-bundle semitendinosus tendon autografts with CC and AC ligament reconstruction for AC joint reconstruction provide AC joint stability and improved function at the final visit.

METHODS

In this retrospective study of prospectively collected data, 21 patients surgically treated for chronic AC joint dislocation (Rockwood III-V) were assessed clinically and radiographically preoperatively, and at day 1, 3 months, 12 months, and at a final visit (>24 months) postoperatively. Clinical assessments included Constant and American Shoulder and Elbow Surgeons scores. The CC vertical distance (CCD) on the affected and unaffected sides [CCD ratio (%)] on the anterosuperior view were measured. AC joint vertical reduction loss was defined as an increase in the CCD ratio of >25%. Horizontal AC joint instability was evaluated on axillary views. Pearsons' correlation coefficients were generated to examine the relationships among postoperative clinical scores, CCD ratio, interval from injury to surgery, and age at the time of surgery.

RESULTS

Twenty-one shoulders in 21 patients (mean age, 40.0 years at the time of surgery; 16 men, 5 women) were evaluated with a mean 31.7-month follow-up period. The mean Constant scores, American Shoulder and Elbow Surgeons scores, and CCD ratios significantly improved from preoperatively to the final visit (57.4 ± 10.1, 49.1 ± 12.1, 101.6 ± 64.1 preoperatively; 89.6 ± 5.3, 96.5 ± 4.2, 9.9 ± 34.5 at the final visit, respectively [P < .001 for all]). Vertical AC and horizontal AC joint instability were observed in 4 shoulders (19.0%) and in 1 shoulder (4.8%), respectively. However, there was no significant correlation between the increase in CCD and clinical scores at the final visit (Constant score; r = 0.179, P = .438: American Shoulder and Elbow Surgeons score; r = -0.260, P = .256) or the interval from injury to surgery (r = 0.099, P = .669) or age at the time of surgery (r = 0.019, P = .935). No clinical complications were associated with clinical symptoms.

CONCLUSIONS

Patients who underwent the index procedure achieved significant improvement in shoulder function without complications related clinical symptom after a mean follow-up interval of 31.7 months. In contrast, the rates of total ACJ instability in the vertical and horizontal planes were unsatisfactory but compatible with those in previous studies.

Tendon graft through the coracoid tunnel versus under the coracoid for coracoclavicular/acromioclavicular reconstruction shows no difference in radiographic or patient-reported outcomes

INTRODUCTION

The purpose of this prospective study was to report the outcomes of two different methods in CC and AC reconstruction for the treatment of AC separation using a tendon graft and knot-hiding titanium clavicular implant.

MATERIALS AND METHODS

Twenty-seven patients with Rockwood grade III and V acromioclavicular (AC) separations were randomized into two groups. The primary outcome was whether taking the tendon graft through the coracoid risked a fracture. The following were secondary outcomes: follow-up of clavicular wound healing and Nottingham Clavicle score, Constant score, and Simple Shoulder Test results obtained preoperatively and 24 months postoperatively. The anteroposterior radiographic change between the clavicular and coracoid cortexes and the clavicular tunnel diameter was measured postoperatively and 24 months postoperatively. General patient satisfaction with the outcome (poor, fair, good, or excellent) was assessed 2 years postoperatively.

RESULTS

No coracoid fractures were detected. No issues in clavicular wound healing were detected. The mean Nottingham Clavicle score increased from a preoperative mean of 42.42 ± 13.42 to 95.31 ± 14.20 (P < 0.00). The Constant score increased from a preoperative mean of 50.81 ± 17.77 to 96.42 ± 11.51 (P < 0.001). The Simple Shoulder Test score increased from a preoperative mean of 7.50 ± 2.45 to 11.77 ± 1.18 (P < 0.001). The changes were significant. The coracoclavicular distance increased from 11.88 ± 4.00 to 14.19 ± 4.71 mm (P = 0.001), which was significant. The clavicular drill hole diameter increased from 5.5 to a mean of 8.00 ± 0.75 mm. General patient satisfaction was excellent.

CONCLUSIONS

There were no significant differences between the two groups. There were no implant related complications in the clavicular wound healing. The results support the notion that good results are achieved by reconstructing both the CC and AC ligaments with a tendon graft.

STUDY REGISTRATION

This clinical trial was registered on Clinicaltrials.gov.

Arthroscopy-assisted procedure provides less residual horizontal instability and optimal coracoid tunnel creation with less radiation exposure compared to percutaneous procedure after endo-button fixation of type III AC joint dislocations

PURPOSE

The aim of this study was to evaluate the postoperative radiological and functional results of patients treated with arthroscopy-assisted (AA) and percutaneous (P) procedures using endo-button for type III acromioclavicular joint dislocations with a minimum 1-year follow-up. The study hypothesis was that the AA technique would provide more favourable coracoid tunnels.

METHODS

This retrospective study included patients who underwent surgery between 2017 and 2022. Computed tomography images taken immediately postoperatively of all the patients were analysed to group coracoid tunnels as optimal or suboptimal based on orientation and placement within the coracoid base. Residual horizontal instability was assessed using the bilateral Alexander view at the final follow-up. Shoulder functions were evaluated at the final follow-up examination.

RESULTS

Of the 63 patients, 39 underwent surgery using the percutaneous procedure and 24 with the AA procedure. Surgical duration was significantly longer in the AA group (AA: 61.1 ± 5.9 min; P: 34.7 ± 5.6 min) (p = 0.001; 95% confidence interval [CI]: 23.3-29.3), whereas fluoroscopy time was longer in the percutaneous group (AA: 2.0 ± 0.8 s; P: 15.7 ± 3.9 s) (p = 0.001; 95% CI: -14.9 to 12.3). Optimal coracoid tunnels were more frequently observed in the AA group (p = 0.001; 95% CI: 7.4-137.8). There was no significant difference in functional scores between the groups (n.s.). Postoperative horizontal instability was more common in the percutaneous procedure (p = 0.013; 95% CI: 8.3-39.2).

CONCLUSIONS

Although no difference was detected between the methods in terms of complications and functional results, the higher frequency of residual horizontal instability, the high risk of suboptimal tunnel creation and greater radiation exposure were seen to be the most important disadvantages of the percutaneous technique. During surgery, such technical problems related to the percutaneous method should be kept in mind and care should be taken about the orientation of the coracoid tunnel.

LEVEL OF EVIDENCE

Level III.

A Self-Designed Endobutton Installation Device for Coracoclavicular Stabilization in Acute Rockwood Type III Acromioclavicular Joint Dislocation

OBJECTIVE

Endobutton technique could provide flexible coracoclavicular (CC) stabilization for acromioclavicular joint (ACJ) dislocation and achieved good clinical outcomes. However, the difficult part of this technique was placement of the Endobutton to the coracoid base. In this study, we designed an Endobutton installation device to place the Endobutton at the coracoid base. And we examined the clinical and radiographic outcomes of patients with acute Rockwood type III ACJ dislocation repaired with Endobutton using this device.

METHODS

We designed an Endobutton installation device to place the Endobutton at the coracoid base to achieve CC stabilization. We retrospectively reviewed 42 patients with acute Rockwood type III ACJ dislocation who underwent CC stabilization with Endobuttons placed either using this novel device (group I, n = 19) or the traditional technique (CC stabilization without using special device, group II, n = 23) from January 2015 to April 2020. The two groups were compared regarding the operative time, intraoperative blood loss, and clinical and radiologic outcomes at final follow-up. The operation-related complications were also evaluated. The Student's t test and the Mann-Whitney U-test were used to compare differences in continuous variables. Differences in categorical variables were assessed with either the Pearson's chi-squared test or Fisher's exact test.

RESULTS

Forty-two patients were clinically followed up for a minimum of 12 months. Compared with group II, group I had a significantly shorter mean operative time (56.05 ± 7.82 min vs. 65.87 ± 7.43 min, p < 0.01) and significantly lesser mean intraoperative blood loss (67.89 ± 14.75 mL vs. 94.78 ± 25.01 mL, p < 0.01). At final follow-up, there were no significant differences between the two groups in the visual analog scale score for pain, Oxford Shoulder Score, Disabilities of the Arm, Shoulder, and Hand score, and postoperative CC distance of the affected side. Loss of reduction occurred in four patients in group I and three patients in group II (p = 0.68); there were no other operation-related complications in either group.

CONCLUSIONS

The Endobutton installation device makes placement of the Endobutton at the coracoid base easier and achieves satisfactory clinical and radiologic outcomes without additional complications in acute Rockwood type III ACJ dislocation.

Suspensory fixation for bone transfer procedures in shoulder instability is superior to screws in an angled construct: a biomechanical analysis

Background

The Latarjet procedure is a common bony augmentation procedure for anterior shoulder instability. Historically, screw fixation is used to secure the coracoid graft to the anterior glenoid surface; however, malpositioning of the graft leads to oblique screw insertion that contributes to complications. Suture buttons (SBs) are a more recent fixation technique that have not been studied alongside standard screw fixation in the context of biomechanical models of angulated fixation. This study aims to compare the biomechanical strength of single and double, screw and SB fixation at various levels of angulation.

Methods

Testing was performed using polyurethane models from Sawbones. The graft piece was secured with screw fixation (Arthrex, Naples, FL, USA) or suspensory button (ABS Tightrope, Arthrex, Naples, FL, USA). Single or double constructs of screws and SBs were affixed at 0°, 15°, and 30° angles to the face of the glenoid component. An aluminum testing jig held the samples securely while a materials testing system applied loads. Five constructs were used for each condition and assessed load to failure testing.

Results

For single fixation constructs, suspensory buttons were 60% stronger than screws at 0° (P < .001), and 52% stronger at 15° (P = .004); however, at 30°, both were comparable (P = .180). Interestingly, single suspensory button at 15° was equivalent to a single screw at 0° (P = .310). For double fixation, suspensory buttons (DT) were 32% stronger than screws at 0° (P < .001) and 35% stronger than screws at 15° (P < .001). Both double fixation methods were comparable at 30° (P = .061). Suspensory buttons at 15° and 30° were equivalent to double screws at 0 (P = .280) and 15° (P = .772), respectively.

Conclusion

These measurements indicate that the suspensory button has a significantly higher load to failure capacity over the screw fixation technique, perpendicularly and with up to 15° of angulation. These analyses also indicate that the suspensory button fixation offers superior strength even when positioned more obliquely than the screw fixation. Therefore, suspensory button fixation may confer more strength while offering greater margin for error when positioning the graft.

The importance of a structured failure analysis in revision acromioclavicular joint surgery: A multi-rater agreement on the causes of stabilization failure from the ISAKOS shoulder committee

BACKGROUND

Acromioclavicular joint (ACJ) stabilizations are associated with a high overall failure rate with 9.5% of these patients requiring subsequent revision surgery. Consequently, understanding the specific cause of primary ACJ stabilization failure is paramount to improving surgical decision-making in this challenging patient cohort.

PURPOSE

To (1) identify risk factors and mechanisms for failure following primary arthroscopically-assisted ACJ stabilization to highlight the importance of conducting a detailed failure analysis and to (2) establish revision strategies based on real-life cases of primary failed ACJ stabilization.

STUDY DESIGN

Level of evidence IV.

METHODS

A survey was shared internationally among members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) shoulder committee. The survey contained failure analysis of 11 real-life cases of failed primary arthroscopically-assisted ACJ stabilization. For each case, a thorough patient history, standardized radiographs, and CT scans were provided. Participants were asked to give their opinion on bone tunnel placement, cause of failure (biological, technical, traumatic, or combined), the stabilization technique used, as well as give a recommendation for revision.

RESULTS

Seventeen members of the ISAKOS shoulder committee completed the survey. Biological failure was considered the most common cause of failure (47.1%), followed by technical (35.3%) and traumatic (17.6%) failure. The majority deemed two modifiable factors (i.e., patient's profession and sport) as well as non-modifiable factors (i.e., patient's age and time from trauma to initial surgery) to be risk factors for failure. In 10 of 11 cases, the correct fixation device was used in the primary setting (90.9%; 52.8-82.4% agreement); however, in eight of those cases, the technique was not performed correctly (80.0%; 58.8-100% agreement). In 8 of all 11 cases, the majority recommended an arthroscopically assisted technique with graft augmentation for revision (52.9-58.8% agreement).

CONCLUSION

Biological failure and technical failure are the most common reason for failure in primary ACJ stabilization followed by traumatic failure. Besides, biological failure can be triggered by technical errors such as clavicular or coracoidal tunnel misplacement. Consequently, a detailed failure analysis including preoperative CT should be conducted on the causes of primary ACJ failure, and, if possible, an arthroscopically-assisted technique with graft augmentation should be prioritized in revision ACJ surgery.

CLINICAL RELEVANCE

ACJ stabilizations are associated with a high overall failure rate - potentially due to biological and technical properties. When encountering failed arthroscopically-assisted ACJ stabilization, a detailed failure analysis should be conducted on the causes of primary ACJ failure. Furthermore, an arthroscopically-assisted revision stabilization is feasible in most cases.

Risk for Fracture with Acromioclavicular Joint Reconstruction and Strategies for Mitigation

Acromioclavicular (AC) joint injuries are a common cause of shoulder pain, especially among athletes. Surgical reconstruction of the AC joint can lead to complications such as fracture of the coracoid process, clavicle or acromion, which can negatively affect the patient's outcome. The purpose of this review is to discuss the risk factors for fractures associated with AC joint reconstruction, as well as the strategies that can be used to mitigate this risk. Risk factors for fractures include low mineral density, coracoid/clavicle drilling, larger holes in the coracoid, and the number of tunnels used for reconstruction.

Transcoracoid Drilling for Coracoclavicular Ligament Reconstructions in Patients With Acromioclavicular Joint Dislocations Result in Eccentric Tunnels

Purpose

To determine the location of coracoid inferior tunnel exit with superior-based tunnel drilling and coracoid superior tunnel exit with inferior-based tunnel drilling.

Methods

Fifty-two cadaveric embalmed shoulders (mean age 79 years, range 58-96 years) were used. A transcoracoid tunnel was drilled at the center of the base. Twenty-six shoulders were used for the superior-to-inferior tunnel drilling approach and 26 shoulders for the inferior-to-superior tunnel drilling approach. The distances to the margins of the coracoid process, from both the entry and exit points of the tunnel, were measured. Paired Student t-tests were used to compare the distance from the center of the tunnel and the medial and lateral coracoid border and the apex.

Results

The mean difference for the distances between superior entry and inferior exit from the apex was 3.65 ± 3.51 mm (P = .002); 1.57 ± 2.27 mm for the lateral border (P = .40) and 5.53 ± 3.45 mm for the medial border (P = .001). The mean difference for the distances between inferior entry and superior exit from the apex was 16.95 ± 3.11 mm (P = .0001); 6.51 ± 3.2 mm for the lateral border (P = .40) and 1.03 ± 2.32 mm for the medial border (P = .045). Inferior-to-superior drilling resulted in 4 (15%) cortical breaks.

Conclusions

Both superior-to-inferior and inferior-to-superior tunnel drilling directed the tunnel from a more anterior and medial entry to a posterior-lateral exit. Superior-to-inferior drilling resulted in a more posteriorly angled tunnel. When using a 5-mm reamer and inferior-to-superior tunnel drilling, cortical breaks were observed at the inferior and medial margin of the tunnel exit.

Clinical Relevance

Arthroscopic-assisted acromioclavicular joint reconstruction using conventional jigs may result in an eccentric coracoid tunnel, possibly introducing stress risers and fractures. To avoid cortical breaks and eccentric tunnel placement, open drilling from superior-to-inferior with a superiorly centered guide pin and arthroscopic visualization of a centered inferior exit should be considered.

Current concepts in acromioclavicular joint (AC) instability - a proposed treatment algorithm for acute and chronic AC-joint surgery

BACKGROUND

There exists a vast number of surgical treatment options for acromioclavicular (AC) joint injuries, and the current literature has yet to determine an equivocally superior treatment. AC joint repair has a long history and dates back to the beginning of the twentieth century.

MAIN BODY

Since then, over 150 different techniques have been described, covering open and closed techniques. Low grade injuries such as Type I-II according to the modified Rockwood classification should be treated conservatively, while high-grade injuries (types IV-VI) may be indicated for operative treatment. However, controversy exists if operative treatment is superior to nonoperative treatment, especially in grade III injuries, as functional impairment due to scapular dyskinesia or chronic pain remains concerning following non-operative treatment. Patients with a stable AC joint without overriding of the clavicle and without significant scapular dysfunction (Type IIIA) may benefit from non-interventional approaches, in contrast to patients with overriding of the clavicle and therapy-resistant scapular dysfunction (Type IIIB). If these patients are considered non-responders to a conservative approach, an anatomic AC joint reconstruction using a hybrid technique should be considered. In chronic AC joint injuries, surgery is indicated after failed nonoperative treatment of 3 to 6 months. Anatomic AC joint reconstruction techniques along with biologic augmentation (e.g. Hybrid techniques, suture fixation) should be considered for chronic high-grade instabilities, accounting for the lack of intrinsic healing and scar-forming potential of the ligamentous tissue in the chronic setting. However, complication and clinical failure rates remain high, which may be a result of technical failures or persistent horizontal and rotational instability.

CONCLUSION

Future research should focus on addressing horizontal and rotational instability, to restore native physiological and biomechanical properties of the AC joint.

Early loss of radiographic reduction after acute acromioclavicular joint reconstruction: Comparison of open Double Endobutton fixation vs. Nottingham Surgilig

INTRODUCTION

Surgical treatment is usually recommended for the acute unstable acromioclavicular joint (ACJ) dislocations. Among the wide variety of different surgical techniques, the Double Endobutton and the Nottingham Surgilig technique are two of the most widely acceptable and well described techniques. The aim of this study was to offer a direct comparison of the above techniques in question, analysing the patients outcomes and assessing the risk of early loss of radiographic reduction.

MATERIALS AND METHODS

A total of 48 patients who met the inclusion criteria were included in the study. Patients were categorised in two groups (Endobutton and Nottingham Surgilig group) and post operative assessment of the patients was performed using the Oxford Shoulder (OSS) and Constant Murley (CMS) scores. Patient demographics, hand dominance, ACJ classification and co-morbidities were included in the analysis and radiographic evaluation was conducted for both groups.

RESULTS

Both techniques provide a good outcome in the management of unstable ACJ dislocations but the risk of early radiographic failure remains higher in the double Endobutton technique (26% vs. 17.39% for the Nottingham Surgilig group). Factors such as patients' demographics, hand dominance, co-morbidities and grade of ACJ separation do not seem to contribute to radiographic loss of reduction, whereas the incorrect positioning of the coracoid endobutton is a significant factor predisposing to early radiographic failure, P < 0.001.

DISCUSSION

The incidence of early loss of radiographic reduction still remains high in both groups. In order to reduce this common complication, accurate placement of the coracoid endobutton under fluoroscopic intra-operative control is strongly recommended.

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.

Hybrid coracoclavicular and acromioclavicular reconstruction in chronic acromioclavicular joint dislocations yields good functional and radiographic results

PURPOSE

Optimal treatment of chronic unstable acromioclavicular (AC) joint dislocations (stage 3-5 according the Rockwood classification) is still debated. Anatomic coracoclavicular (CC) reconstruction is a reliable option in terms of two-dimensional radiographic reduction, clinical outcomes, and return to sports, but there remain concerns regarding anterior-posterior stability of the AC joint with CC ligament reconstruction alone. The aim of the present study was to describe the mid-term results of a new hybrid technique with CC and AC ligament reconstruction for chronic AC joint dislocations.

METHODS

Twenty-two patients surgically treated for chronic AC joint dislocations (grade 3 to 5) were retrospectively reviewed. All patients were assessed before surgery and at final follow-up with the Constant-Murley score (CMS) and the American Shoulder and Elbow Surgeons (ASES) score. The CC vertical distance (CCD) and the CCD ratio (affected side compared to unaffected side) were measured on Zanca radiographs preoperatively, at 6 months postop and at final follow-up. The same surgical technique consisting in a primary fixation with a suspensory system, coracoclavicular ligaments reconstruction with a double loop of autologous gracilis and acromioclavicular ligaments reconstruction with autologous coracoacromial ligament was performed in all cases.

RESULTS

Twenty-two shoulders in 22 patients (19 males and 3 females) were evaluated with a mean age of 34.4 ± 9 years at the time of surgery. The mean interval between the injury and surgery was 53.4 ± 36.7 days. The mean duration of postoperative follow-up was 49.9 ± 11.8 months. According to the Rockwood classification, there were 5 (22.6%) type-III and 17 (77.2%) type-V dislocations. Mean preoperative ASES and CMS were 54.4 ± 7.6 and 64.6 ± 7.2, respectively. They improved to 91.8 ± 2.3 (p = 0.0001) and 95.2 ± 3.1 (p = 0.0001), respectively at final FU. The mean preoperative CCD was 22.4 ± 3.2 mm while the mean CCD ratio was 2.1 ± 0.1. At final FU, the mean CCD was 11.9 ± 1.4 mm (p = 0.002) and the mean CCD ratio was 1.1 ± 0.1 (p = 0.009). No recurrence of instability was observed. One patient developed a local infection and four patients referred some shoulder discomfort. Heterotopic ossifications were observed in three patients.

CONCLUSIONS

The optimal treatment of chronic high-grade AC joint dislocations requires superior-inferior and anterior-posterior stability to ensure good clinical outcomes and return to overhead activities or sports. The present hybrid technique of AC and CC ligaments reconstruction showed good clinical and radiographic results and is a reliable an alternative to other reported techniques.

LEVEL OF EVIDENCE

Level IV.

Biomechanical Analysis of Coracoid Stability After Coracoplasty: How Low Can You Go?

Background:

Arthroscopic coracoplasty is a procedure for patients affected by subcoracoid impingement. To date, there is no consensus on how much of the coracoid can be resected with an arthroscopic burr without compromising its stability.

Purpose:

To determine the maximum amount of the coracoid that can be resected during arthroscopic coracoplasty without leading to coracoid fracture or avulsion of the conjoint tendon during simulated activities of daily living (ADLs).

Study Design:

Controlled laboratory study.

Methods:

A biomechanical cadaveric study was performed with 24 shoulders (15 male, 9 female; mean age, 81 ± 7.9 years). Specimens were randomized into 3 treatment groups: group A (native coracoid), group B (3-mm coracoplasty), and group C (5-mm coracoplasty). Coracoid anatomic measurements were documented before and after coracoplasty. The scapula was potted, and a traction force was applied through the conjoint tendon. The stiffness and load to failure (LTF) were determined for each specimen.

Results:

The mean coracoid thicknesses in groups A through C were 7.2, 7.7, and 7.8 mm, respectively, and the mean LTFs were 428 ± 127, 284 ± 77, and 159 ± 87 N, respectively. Compared with specimens in group A, a significantly lower LTF was seen in specimens in group B (P = .022) and group C (P < .001). Postoperatively, coracoids with a thickness ≥4 mm were able to withstand ADLs.

Conclusion:

While even a 3-mm coracoplasty caused significant weakening of the coracoid, the individual failure loads were higher than those of the predicted ADLs. A critical value of 4 mm of coracoid thickness should be preserved to ensure the stability of the coracoid process.

Clinical Relevance:

In correspondence with the findings of this study, careful preoperative planning should be used to measure the maximum reasonable amount of coracoplasty to be performed. A postoperative coracoid thickness of 4 mm should remain.

Arthroscopic Coracoclavicular Reconstruction Combined with Open Acromioclavicular Reconstruction Using Knot Hiding Clavicular Implants Is a Stable Solution

Purpose

The purpose of this noninterventional, register-based study was to report the outcomes and wound healing of surgically treated chronic acromioclavicular (AC) dislocations using a tendon graft and knot-hiding titanium implants.

Methods

Thirty-two cases with chronic AC separation underwent an arthroscopic coracoclavicular (CC) ligament reconstruction and an open AC ligament reconstruction using knot-hiding titanium implants. The wound healing was assessed 2 months after the operation. The Nottingham Clavicle score, Constant score, and Simple Shoulder Test were obtained postoperatively and at a minimum of one-year postsurgery. The radiographic change in distance between the clavicular and coracoid cortices and clavicular tunnel diameter was measured. General patient satisfaction with the outcome (poor, fair, good, or excellent) was also assessed 1 year postoperatively.

Results

The mean Nottingham Clavicle score increased from a preoperative mean of 41.66 ± 9.86 to 96.831 ± 5.86 (P ≤ .05). The Constant score increased from a preoperative mean of 44.66 ± 12.54 to 93.59 ± 7.01 (P ≤ .05). The Simple Shoulder Test score increased from a preoperative mean of 7.00 ± 2.14 to 11.84 ± .63 (P ≤ .05). The coracoclavicular distance increased from 11.32 ± 3.71 to 13.48 ± 3.79 mm (P ≤ .05). The clavicular drill hole diameter increased from 6 mm to a mean of 6 to a mean of 8.13 ± 1.12 mm. Twenty-three (71.9%) patients reported an excellent outcome, and nine (28.1%) reported a good outcome. One clavicular fracture occurred but no coracoid fractures. There was one reconstruction failure leading to a reoperation.

Conclusions

In this series, combining the arthroscopic CC ligament reconstruction to an open reconstruction of the AC joint with a tendon graft proved to be a stable solution. The knot-hiding titanium implant effectively eliminated the problems related to the clavicular wound healing.

Level of Evidence

Level IV, therapeutic case series.

Position of Coracoid Button Predicts Loss of Reduction in Acromioclavicular Joint Dislocation Patients Treated With the Suture-Button

BACKGROUND

Loss of reduction is the most common complication after acromioclavicular (AC) joint dislocation treated with the suture-button. Some predictors of it are known, but finding new predictors is an ongoing process. In this study, we evaluate the importance of the position of the coracoid button.

MATERIALS AND METHODS

Between April 2010 and February 2017, 186 patients with AC joint dislocation were identified. All patients were managed with the same surgical technique and postoperative protocol. The position of the coracoid button was determined immediately after surgery by anterior-posterior views of the operated shoulder and was classified as medial (Group A, 42 cases), central (Group B, 85 cases) and lateral (Group C, 59 cases) positions. The main outcome measurement was loss of reduction. The main analysis was the association between the coracoid button position and loss of reduction.

RESULTS

No significant difference was found in the baseline characteristics among 3 groups. During follow-up, there were 15 cases (35.7%) developing loss of reduction in Group A, 5 cases (5.9%) in Group B and 26 cases (44.1%) in Group C. The rate of loss of reduction in Groups A and C were higher than that in Group B (p < .05). Moreover, there was no significant difference in the rate of reduction loss between lateral and medial positions of the coracoid buttons (p > .05).

CONCLUSION

Our results indicated that both lateral and medial positions of the coracoid buttons could predict loss of reduction in AC joint dislocation patients treated with the suture-button.

Coracoid or Clavicle Fractures Associated With Coracoclavicular Ligament Reconstruction

BACKGROUND

Coracoclavicular (CC) ligament reconstruction is a commonly performed procedure for high-grade acromioclavicular (AC) joint separations. Although distal clavicle and coracoid process fractures represent potential complications, they have been described in only case reports and small case series.

PURPOSE

To identify the incidence and characteristics of clavicle and coracoid fractures after CC ligament reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The US Military Health System Data Repository was queried for patients with a Current Procedural Terminology code for CC ligament repair or reconstruction between October 2013 and March 2020. The electronic health records, including patient characteristics, radiographs, operative reports, and clinical notes, were evaluated for intraoperative or postoperative clavicle or coracoid fractures. Initial operative technique, fracture management, and subsequent clinical outcomes were reviewed for these patients.

RESULTS

A total of 896 primary CC ligament repairs or reconstructions were performed during the study period. There were 21 postoperative fractures and 1 intraoperative fracture in 20 patients. Of these fractures, 12 involved the coracoid and 10 involved the clavicle. The overall incidence of fracture was 3.81 fractures per 1000 person-years. In 5 patients who sustained a fracture, bone tunnels were not drilled in the fractured bone during the index procedure. A total of 17 fractures were ultimately treated operatively, whereas 5 fractures had nonoperative management. Of the 16 active-duty servicemembers who sustained intraoperative or postoperative fractures, 11 were unable to return to full military duty after their fracture care.

CONCLUSION

Fracture of the distal clavicle or coracoid process after CC ligament repair or reconstruction is a rare but serious complication that can occur independent of bone tunnels created during the index procedure. Fractures associated with CC ligament procedures occurred at a rate of 2.46 per 100 cases. Most patients were ultimately treated surgically with open reduction and internal fixation or revision CC ligament reconstruction. Although the majority of patients with intraoperative or postoperative fractures regained full range of motion, complications such as anterior shoulder pain, AC joint asymmetry, and activity-related weakness were common sequelae resulting in physical limitations and separation from military service.

Distal clavicle fractures with "superior intact cortical bone": minimally invasive surgery

Introduction

Distal clavicle fractures represent 12%-26% of all clavicle fractures. For unstable cases, surgical fixation is the preferred method of treatment. To date, there is still controversy regarding the best fixation method with a high reoperation and complication rate reported. The purpose of this article is to describe a minimally invasive method for reduction and stabilization of displaced distal clavicle fractures, using cortical buttons.

Surgical technique

After standard preoperative preparation, a 3-cm incision is made at the coracoclavicular area. Using both coracoid and clavicle tunnels, fracture reduction and fixation is obtained using a cortical fixation button. Standard postoperative care is given.

Results

A total of 21 patients (19 men) with a mean age of 34.7 years were treated using this technique. The follow-up was between 6 and 41 months, with an average of 23.4 months. The mean simple shoulder test score was 79.4 (range 66-91.7), and the QuickDASH score was 11 (range 6.8-15.9). Consolidation of the fracture was confirmed at the 12-week follow-up radiography, with no cases of nonunion or malunion identified. No patients presented infection or complications at the surgical site. Implant removal was not needed in this series. All the patients returned to work.

Conclusion

Minimally invasive button fixation of unstable distal clavicle fractures is a safe and reliable alternative treatment. The initial outcome report is promising with excellent clinical and radiological results and no complications or implant removals.

Clinical outcomes of arthroscopic and navigation-assisted two tunnel technique for coracoclavicular ligament augmentation of acute acromioclavicular joint dislocations

Background

The purpose of this study was to present a navigated image-free augmentation technique for the acromioclavicular joint (ACJ) and coracoclavicular (CC) ligaments and to report the clinical and radiological outcomes.

Methods

From 2013 to 2018, 35 eligible patients were treated with our navigated image-free ACJ- and CC-augmentation technique. The average follow-up was 3 years. Follow-up evaluations included the Constant-Murley Score, subjective shoulder value, Taft score, and the acromioclavicular joint instability (ACJI) score. The patients’ quality of life was assessed using the EuroQol-5D (EQ-5D) questionnaire. In addition, in accordance with the instability criteria, radiographs were evaluated before surgery, after surgery, and during follow-up.

Results

Overall, 25 patients (71%) suffered an acute type V disruption, 5 (14%) had a type IV disruption, and 5 (14%) had an acute Rockwood type IIIb injury. The mean Constant-Murley Score was 90 (range: 56–100; p = 0.53) on the injured side, and the mean subjective shoulder value was 92% (range: 80–100%). The mean Taft and ACJI scores were 10 (range: 4–12) and 86 (range: 34–100), respectively and the mean EQ-5D was 86 (range: 2–100). The mean CC difference of the injured side was 4 mm (range: 1.9–9.1 mm) at follow-up, which was not significantly different than that of the healthy side (p = 0.06). No fractures in the area of the clavicle or the coracoid were reported.

Conclusions

The arthroscopic- and navigation-assisted treatment of high-grade ACJ injuries in an anatomical double-tunnel configuration yields similar clinical and radiological outcomes as the conventional technique using an aiming device. Precise positioning of the navigation system prevents multiple drillings, which avoids fractures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04406-2.

Risk factors related to the loss of reduction after acromioclavicular joint dislocation treated with the EndoButton device

Background

Anatomic ligament reconstruction using the EndobutBon device has been proven an effective technique for the management of acute acromioclavicular (AC) joint dislocation. The aim of this study was to analyze the risk factors causing loss of reduction after AC joint dislocation treated with the EndoButton device for open procedures.

Methods

A total of 107 patients who met the inclusion and excluded criteria finally were enrolled. We retrospectively analyzed the clinical tests, imaging data, and postoperative rehabilitation of patients in a stable reduction group and a loss of reduction group.

Results

Among all patients included in the study, the incidence of reduction failure was 14%. Univariate analysis identified that the time between injury to surgery, double or triple EndoButton, coracoid EndoButton position, weight-bearing time of the upper limb, and osteolysis had statistically significant associations with loss of reduction for the AC joint (P=0.022, 0.002, 0.000, 0.000, and 0.000 respectively). By using multivariate logistic regression analysis, we found that coracoid EndoButton position (P=0.002), weight-bearing time of the upper limb (P=0.011), and osteolysis (P=0.036) were the significant independent risk factors related to the loss of reduction after AC joint dislocation treated with the EndoButton device used with open procedures.

Conclusions

In order to reduce the incidence of reduction failure and improve the prognosis of patients, more accurate placement of EndoButton plates in surgery and guidance for patients in completing planned rehabilitation training are needed.

Arthroscopic Coracoclavicular Ligament Stabilization Using Coracoid Cortical Suspension in Acute Acromioclavicular Joint Injury; Precision of Drill Tunnel

Acute acromioclavicular joint separation is a common injury of the shoulder. There are several methods for treating this condition; however, there is no gold standard established. Herein, we propose an arthroscopic method for the treatment of acute acromioclavicular joint separation using a simple cortical suspension device at the coracoid base via a transclavicular-transcoracoidal tunnel and tieing the suture at the clavicle. This method has the advantages of making a precision drilling tunnel using small implants and small stab incisions, with better cosmetic results and less implant irritation.

Chronic acromioclavicular dislocations: multidirectional stabilization without grafting

Objective

Clinical and radiological evaluation of the surgical treatment of chronic acromioclavicular (AC) dislocations with triple button device and AC joint augmentation.

Materials and Methods

This retrospective study included 21 patients with chronic AC dislocations. All patients underwent bilateral-weighted Zanca and Alexander views as well as the Constant score (CS) and Acromioclavicular Joint Instability Scoring System (ACJI).

Results

A total of 21 patients (19 men and 2 women) with the mean age of 30.7 ± 11.7 years (range, 19-62 years) were able to participate in clinical and radiographic follow-up. After a mean follow-up of 49.7 ± 17.1 months (range, 13-60 months), the results of the CS were 95.2 ± 5.5 (range, 85-100) and ACJI test 89.7 ± 7.9 (range, 75-100), showing no significant differences with the uninjured shoulder (CS, 96.2 ± 3.9; range, 85-100; ACJI, 95.7 ± 4.1; range, 85-100). At the final review, we observed that the preoperative coracoclavicular distance (Zanca view) improved from 12.8 ± 1.5 mm to 8.5 ± 1.3 mm and the AC distance (Alexander view) from 7.8 ± 2.3 mm to 0.99 ± 0.91 mm. Compared with healthy shoulder, these differences were not significant. Osteoarthritis or radiological calcifications were not associated with worse clinical outcomes.

Conclusion

The triple button device is an acceptable alternative surgical method for chronic AC joint dislocations. The surgical technique is simple; it does not need a graft, nor does it present major complications, and material extraction is unnecessary.

Sagittal orientation of coracoclavicular ligament reconstruction affects the stability of surgical repair

BACKGROUND

The variation in the anatomic relationship between the coracoid and the clavicle affects the biomechanical stability of coracoclavicular ligament reconstruction (CCLR).

METHODS

Three-dimensional computed tomography reconstruction of 85 patients was analyzed. Anatomic landmarks were used to derive the coracoclavicular sagittal reconstruction angle (sRA). The lateral concave angle, which indicated the shape of the distal clavicle, and the offsets between the clavicle and coracoid were also measured. To investigate the biomechanical effects of the sRA on CCLR, 7 computed tomography scans with different sRAs were 3D printed. Two reconstructions, a single trans-coracoclavicular tunnel and a looped reconstruction technique, were performed sequentially. Models were cyclically loaded at 70 N in the anterior, posterior, and superior directions.

RESULTS

The mean sRA was 68° ± 9.3° (range, 47°-85°). The superoinferior offset between the clavicle and the coracoid and the lateral concave angle positively correlated with the sRA (r = 0.359 and 0.837, respectively; P ≤ .001), whereas the anteroposterior offset had a negative correlation (r = -0.925; P < .001). The sRA had a negative correlation with the anterior displacement of the clavicle (rho = -0.96; P < .001) and a positive correlation with the posterior displacement for both surgical techniques (rho = 1.0; P < .001).

CONCLUSION

The anatomic orientation of the native coracoclavicular ligaments is highly variable in the sagittal plane. Low sagittal angles can reduce anterior stability, whereas high sagittal angles can reduce posterior stability of CCLR.

The frequency of reduction loss after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device, and its effect on clinical and radiological results

Background

The aim of this study was to investigate the effect of reduction loss of more than 3 mm on clinical and radiological results after at least 2 years of follow-up after arthroscopic fixation of acute acromioclavicular joint dislocations using a double-button device.

Methods

Thirty-six patients who had acute (< 3 weeks old), type III or V acromioclavicular (AC) joint dislocations underwent arthroscopic fixation of the AC joint using a double-button device. Clinical and radiological evaluations were performed at preoperative, postoperative first day, 3 months and last follow-up. When the coracoclavicular (CC) distances of patients at the last follow-up were compared to the early postop CC distances, those with a difference of 3 mm or less were grouped as group A and those with a difference of more than 3 mm were grouped as group B.

Results

There was no statistically significant difference between the groups in terms of age, gender, follow-up time, time from injury to surgery, return to work, and distribution of Rockwood classification. Pre-operative CC distance was reduced from 18.7 ± 3.5 to 8.5 ± 0.6 in the early postoperative period. Anatomic reduction was achieved in all patients compared with the unaffected side (CC distance 8.6 ± 0.7). However, the CC distance increased to 9.9 ± 1.5 at the third-month follow-up and increased to 11 ± 2.7 at the last follow-up. There were no significant Constant score differences between the groups in the preoperative and last follow-up periods (p > 0.05). At the last follow-up, the mean Acromioclavicular Joint Instability (ACJI) score of group A was 84.4 ± 8, whereas it was 68.3 ± 8.3 for group B, and the difference was statistically significant (p < 0.01). Furthermore, the subjective evaluation and aesthetic subjective satisfaction values of group B were lower than group A (p < 0.01).

Conclusions

Reduction loss of more than 3 mm was observed in 25% of patients after arthroscopic fixation of acute acromioclavicular dislocations using a double-button device. Although this loss did not create a statistically significant difference in Constant scores, AC joint-specific tests such as ACJI, subjective evaluation, and aesthetic subjective satisfaction values were significantly impaired.

Comparison of two methods for coracoclavicular ligament reconstruction: A finite element analysis

OBJECTIVE

This study aimed to compare two different tendon grafting techniques for coracoclavicular ligament reconstruction from the data obtained using finite element analysis.

METHODS

Three different finite element models of the shoulder girdle were formulated using computerized tomography images: the reference model, coracoid loop technique (CLT), and drilling technique (DT) model. In all these models, forces were applied to the clavicle along three axes (x, y, and z) of the trapezius and sternocleidomastoid muscles. Thereafter, data regarding the loading values of the tendon grafts, loads on the coracoid base, and coracoclavicular vertical distance were measured.

RESULTS

While the reference model yielded the lowest values for all the loading conditions as well as the shortest coracoclavicular distance, the DT model demonstrated the highest values for all the loading conditions and the largest coracoclavicular distance.

CONCLUSION

Different tendon grafting techniques may offer different loading values on both bone surface and tendon graft during coracoclavicular ligament reconstruction. The drilling technique may be associated with increased loading on the tendon graft and bone surface, causing further loss of reduction and consequent complications.

Radiological study of the Asian coracoid process and clavicle: Implications for coracoclavicular ligament reconstruction

PURPOSE

Iatrogenic coracoid and clavicle fracture is a known complication of drilling bone tunnels during anatomic coracoclavicular ligament reconstruction (ACCR). This study aims to measure the dimensions of coracoid process and clavicle in an Asian population to evaluate the suitability of drilling coracoid and clavicle tunnels for ACCR in Asians.

METHODS

Width measurements of 196 coracoids and 189 clavicles were obtained after reviewing all computed tomography (CT) scans of the shoulder performed over a 6 years period. Coracoid measurements were made on the CT slice which showed the maximum cross sectional width of the coracoid base. Medial to lateral measurements of the coracoid width were taken on an axial view, 4 mm above the identified junction of the coracoid base and glenoid base. Antero-posterior clavicle width was measured through a point directly above the midpoint of the coracoid and perpendicular to the long axis of the clavicle.

RESULTS

The overall mean coracoid width was 14.8 mm ± 2.54 mm (range 9.2-23.3 mm) and clavicle width was 17.1 mm ± 2.72 mm (range 11.1-25.3 mm).

CONCLUSION

The Asian coracoid process is smaller than its Western equivalent. More research is required to validate this conclusion as no cadaveric studies with equivalent measurement techniques have been performed on Asians. Given the potentially narrower dimensions of the Asian coracoid process, extra precautions are required to minimize the risk of iatrogenic coracoid and clavicle fractures.

Coracoclavicular Double-Button Fixation of Displaced Lateral Clavicular Fracture in a Patient without Coracoid Process

Background

Displaced distal clavicular fractures are generally operated on because of the high nonunion rate after nonoperative treatment. Several surgical techniques have been developed to reduce the nonunion rate and improve functional outcomes. One of them is closed reduction and minimally invasive coracoclavicular double-button fixation, which requires the integrity of the coracoid process to be performed.

Case Summary

We present a 35-year-old male patient who had been successfully subjected to a modified Latarjet procedure for glenohumeral instability with bony defect treatment, and 7 months later suffered a distal clavicle fracture in his ipsilateral shoulder. With a CT scan, we analyzed the coracoid remnant size (7 mm), and we consider it enough to perform a minimally invasive double-button technique, using this remnant as a distal fixation.

Postoperative and Follow-Up

Radiographic and clinical fracture union occurred 10 weeks after the procedure. The patient returned to sports at the same level he had before surgery and achieved full strength and range of motion.

Conclusion

Closed reduction and minimally invasive double-button fixation of displaced distal clavicular fractures is a safe, reproducible, and versatile technique, which can even be performed without an intact coracoid process.

Arthroscopic Coracoclavicular Ligament Reconstruction of Chronic Acromioclavicular Dislocations Using Autogenous Semitendinosus Graft: A Two-Year Follow-up Study of 58 Patients

Purpose

To determine the results of operatively treated chronic acromioclavicular (AC) joint dislocations after 2-year follow-up.

Methods

Fifty-eight patients with chronic acromioclavicular separations underwent arthroscopic coracoclavicular ligament reconstructions using semitendinosus autografts. Constant and Simple Shoulder Test scores were determined before and 2 years after surgery as a part of standard clinical practice. General patient satisfaction with the outcome (poor, fair, or excellent) also was assessed. In addition, for purposes of routine clinical follow-up, the coracoclavicular distance was measured from the inferior cortex of the clavicle to the superior cortex of the coracoid using anteroposterior radiographs taken 2 years after surgery. The results were compared with postoperative radiographs and changes in the distance were recorded. The clavicular drill hole was similarly measured 2 years after surgery to detect possible tunnel widening.

Results

The mean preoperative Constant score increased from a preoperative mean of 52.6 ± 16.5 to 94.7 ± 7.9 at 2 years postoperatively (P = .000). The Simple Shoulder Test score increased from a preoperative mean of 7.7 ± 1.64 to 11.8 ± 0.7 (P = .000). The mean coracoclavicular distance increased from 10.5 ± 3.4 to 12.4 ± 3.9 mm (P = .009). The diameter of the clavicular drill hole increased from 6.0 mm to a mean of 8.4 mm. Two coracoid fractures were observed, but no clavicular fractures. One patient experienced a deep infection, leading to total reconstruction failure, and 2 patients had superficial postoperative infections. Forty-five patients (85%) reported excellent subjective outcomes, and 8 (15%) reported a fair outcome.

Conclusions

The outcomes of this series of coracoclavicular ligament reconstruction were favorable and the number of serious complications was small. However, clavicular wound issues were a significant problem. Coracoclavicular ligament reconstruction is a challenging procedure, but satisfactory results can be achieved with careful patient selection and good technique.

Level of Evidence

Level IV, therapeutic case series

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.

Analysis of risk factors for loss of reduction after acromioclavicular joint dislocation treated with the suture-button

BACKGROUND

The most commonly reported complication after acromioclavicular (AC) joint dislocation treated with the Suture-button is loss of reduction. Loss of reduction is a major factor influencing the patient's joint function and subjective satisfaction. The objective of this study is to analyze the risk factors causing loss of reduction after AC joint dislocation treated with the Suture-button.

METHODS

One hundred and thirty patients with AC joint dislocation who were surgically treated the Suture-button in our hospital from February 2009 to February 2015, were recorded their age, sex, BMI, time from injury to surgery, Rockwood's classification, with or without osteoporosis, double or triple button technique, position of the clavicle tunnel, tunnel diameter, coracoid button position, alignment of the button, acromioclavicular ligament repair or not, different methods of postoperative limb immobilization, and so on. Mean comparisons or chi-square test was used for univariate analysis of the above factors, and then multivariate logistic regression analysis was performed to predict risk factors.

RESULTS

Reduction was lost in 23.1% of the patients. Univariate analysis showed that button alignment, double or triple button technique, coracoid button position, position of the clavicle tunnel, acromioclavicular ligament repair or not and osteoporosis had statistically significant association with loss of reduction for AC joint (P = 0.031, 0.034, 0.000, 0.042, 0.047 and 0.000 respectively). Multivariate logistic regression analysis demonstrated that osteoporosis (P = 0.003), position of the clavicle tunnel (P = 0.032) and coracoid button position (P < 0.001) were the risk factors that significantly associated with the loss of reduction after AC joint dislocation treated with the Suture-button.

CONCLUSIONS

Clavicle tunnel location using relative ratio method, accurate placement of button plate under coracoid process (inside or outside deviation <20°), various reinforcement operations for patients with osteoporosis are important factors in preventing loss of reduction.

Shoulder Acromioclavicular and Coracoclavicular Ligament Injuries: Common Problems and Solutions

Injuries to the acromioclavicular joint and coracoclavicular ligaments are common. Many of these injuries heal with nonoperative management. However, more severe injuries may lead to continued pain and shoulder dysfunction. In these patients, surgical techniques have been described to reconstruct the function of the coracoclavicular ligaments to provide stable relationship between the clavicle and scapula. These surgeries have been fraught with high complication rates including clavicle and coracoid fractures, infection, loss of reduction and fixation, hardware migration, and osteolysis. This article reviews common acromioclavicular and coracoclavicular repair and reconstruction techniques and associated complications, and provides recommendations for prevention and management.

Functional and Radiographic Outcomes After Allograft Anatomic Coracoclavicular Ligament Reconstruction

OBJECTIVES

To analyze the functional and radiographic outcomes of anatomic coracoclavicular ligament reconstruction (ACCR) using allograft tendon without interference screw fixation.

DESIGN

Retrospective nonrandomized study.

SETTING

Level I trauma center (University Hospital).

PATIENTS

Seventeen patients (mean age of 44 years) with Rockwood III through V acromioclavicular joint disruptions. Twelve of 17 patients had a primary reconstruction, including 4 patients sustaining their injuries as part of a polytrauma incident. Five of 17 patients were revisions of a previously failed acromioclavicular reconstruction procedure.

INTERVENTION

Open ACCR using hamstring allograft with high-strength suture augmentation and knotted graft fixation without interference screws.

MAIN OUTCOME MEASURES

Clinical and patient reported outcome measures including Simple Shoulder Test, American Shoulder and Elbow Surgeons scores, and visual analog scale scores for pain and radiographic outcomes.

RESULTS

The average final postoperative Simple Shoulder Test and American Shoulder and Elbow Surgeons scores were 10.8 and 80.5, respectively. The average final postoperative visual analog scale pain was 1.8. All patients demonstrated clavicle tunnel widening on final postoperative radiographs compared with immediate postoperative radiographs. The overall complication rate was 36%, with no clavicle or coracoid fractures.

CONCLUSIONS

Open ACCR using hamstring allograft tendon secured with a square knot and high-strength suture augmentation yields equivalent outcomes to those repairs requiring an additional interference screw. Clavicle tunnel widening predictably occurs, but the clinical significance is undetermined. It appears therefore that an interference screw is not needed. Larger comparison studies are needed.

LEVEL OF EVIDENCE

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

Acromioclavicular joint dislocation: a Dog Bone button fixation alone versus Dog Bone button fixation augmented with acromioclavicular repair-a finite element analysis study

BACKGROUND

Suspension suture button fixation was frequently used to treat acromioclavicular joint (ACJ) dislocation. However, there were many studies reporting about complications and residual horizontal instability after fixation. Our study compared the stability of ACJ after fixation between coracoclavicular (CC) fixation alone and CC fixation combined with ACJ repair by using finite element analysis (FEA).

MATERIALS AND METHODS

A finite element model was created by using CT images from the normal shoulder. The model 1 was CC fixation with suture button alone, and the model 2 was CC fixation with suture button combined with ACJ repair. Three different forces (50, 100, 200 N) applied to the model in three planes; inferior, anterior and posterior direction load to the acromion. The von Mises stress of the implants and deformation at ACJs was recorded.

RESULTS

The ACJ repair in the model 2 could reduce the peak stress on the implant after applying the loading forces to the acromion which the ACJ repair could reduce the peak stress of the FiberWire at suture button about 90% when compared to model 1. And, the ACJ repair could reduce the deformation of the ACJ after applying the loading forces to the acromion in both vertical and horizontal planes.

CONCLUSION

This FEA supports that the high-grade injuries of the ACJ should be treated with CC fixation combined with ACJ repair because this technique provides excellent stability in both vertical and horizontal planes and reduces stress to the suture button.

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

PURPOSE

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.

METHODS

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. 4.5 mm). Furthermore, the tunnel length and distance between tunnels were altered. Forty-five cadaveric specimens (median age: 64 years, range 33-71 years) 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.

RESULTS

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 (4.5 mm) had the most impact on load to failure reduction. A long horizontal tunnel with a diameter of 4.5 mm reduced the load to failure with medial direction of force to 25% of the native acromion. The identical tunnel with a diameter of 2.4 mm 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.

CONCLUSION

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 4.5 mm. 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.

Study on the anatomic relationship between the clavicle and the coracoid process using computed tomography scans of the shoulder

BACKGROUND

The current trend in the treatment of acromioclavicular dislocations is to reconstruct the coracoclavicular ligaments by using transosseous tunnels in the coracoid process or in the clavicle, yet there is no definition as to the location of these. To study the anatomic relationship between the coracoid process and the clavicle, we made measurements to find a convergence point (cP) between them that has intraoperative applicability for creating transosseous tunnels.

METHODS

We analyzed 74 computed tomography scans (40 female and 34 male patients). Measurements were taken in the axial and sagittal planes and obtained from a cP, as determined by the intersection of the cortical surface of the clavicle and the coracoid process, with various relationships having been established.

RESULTS

On average, the cP was determined to be about 2.9 cm and 2.5 cm distant from the coracoid process apex for male and female patients, respectively, whereas the width at this position was determined to be 2.1 cm and 1.9 cm. In the clavicle, this point is on average 2.9 cm and 2.5 cm distant from the acromioclavicular joint in male and female patients, respectively, and its anteroposterior width at this point is on average 1.9 cm and 1.6 cm.

CONCLUSION

The cP of the clavicle and the coracoid process was determined with the aim of preparing bone tunnels in operations for treating acromioclavicular 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.

A comparison of double Endobutton and triple Endobutton techniques for acute acromioclavicular joint dislocation

PURPOSE OF THE STUDY

The purpose of this study was to evaluate the results of patients treated with either double Endobutton device or triple Endobutton device for acute acromioclavicular joint dislocations.

PATIENTS AND METHODS

Eighty patients were randomized to operative stabilization either by double Endobutton device (group A, 40) or by triple Endobutton device (group B, 40). Preoperative variables included the patients' age, sex, the affected side, cause of injury, Rockwood classification and time from injury to surgery. Peri-operative variables were incision length, blood loss, the operative time and the radiation time, length of hospitalization and hospital costs. Postoperative variables were complications, the Constant and VAS scores and the ability to return to previous work. The coracoclavicular (CC) distance of the affected shoulder was assessed on a standard radiograph and compared with the contralateral normal one.

RESULTS

The average follow-up time of group A was 26.5±7.3months and group B was 24.2±6.6months. The overall complication rate was similar in both groups (26/40 vs. 24/40, P=0.644). There were no significant differences in the mean incision length, blood loss, the operative and radiation time, length of hospitalization, the Constant and VAS scores, and the ability to return to previous work between the two groups. However, the patients of group B had more hospital costs (3802.5±258.5 vs. 2433.6±182.5 USD, P=0.000). The radiological assessment revealed no significant difference in the CC distance between the two groups (P=0.625).

DISCUSSIONS

Triple Endobutton technique did not show significant clinical advantages over double Endobutton technique.

LEVEL OF EVIDENCE

Level II prospective randomized study.

All arthroscopic augmented Vargas procedure: An option after failed acromioclavicular joint dislocation reconstruction. A technical note

Few salvage procedures have been described after a failed Weaver-Dunn procedure. We hypothesized that it was possible to perform an all-arthroscopic revision with a reflected vascularized conjoint tendon into the distal resected clavicle (Vargas procedure) augmented by an artificial coraco-clavicular ligament. Two patients were enrolled. A minimum of 3-cm proximal conjoint tendon was dissected under arthroscopic control. The half-longitudinal conjoint tendon split, leaving its proximal end attached to the coracoid process, was made and incised transversely near the muscles fibers. While being still vascularized with the tip of the coracoid process, the tendon was tubularized, reflected proximally and transferred into the distal part of the clavicle. An artificial coraco-clavicular ligament augmented the transfer. No complication was described. After a minimum of two-year follow-up, there was no recurrence of AC instability and there was normal ROM; two patients returned to sport.

LEVEL OF EVIDENCE

Level IV-a, case series.

Effect of Coracoid Drilling for Acromioclavicular Joint Reconstruction Techniques on Coracoid Fracture Risk: A Biomechanical Study

PURPOSE

To biomechanically compare the stability of the coracoid process after an anatomic double-tunnel technique using two 4-mm drill holes or a single-tunnel technique using one 4-mm or one 2.4-mm drill hole.

METHODS

For biomechanical testing, 18 fresh-frozen cadaveric scapulae were used and randomly assigned to one of the following groups: two 4-mm drill holes (group 1), one 4-mm drill hole (group 2), or one 2.4-mm drill hole (group 3). After standardized coracoid drilling, load was applied to the conjoined tendons at a rate of 120 mm/min and ultimate failure load, along with the failure mode, was recorded.

RESULTS

There was no significant difference between groups regarding load to failure. Mean load to failure in group 1 was 392 N; group 2, 459 N; and group 3, 506 N. The corresponding P values were .55, .74, and .20 for group 1 versus group 2, group 2 versus group 3, and group 1 versus group 3, respectively. However, the failure mode for the group with one 4-mm drill hole and the group with two 4-mm drill holes was coracoid fracture, whereas the group with one 2.4-mm drill hole showed 5 tears of the conjoined tendons and only 1 coracoid fracture (P = .015).

CONCLUSIONS

Although there was no significant difference regarding load-to-failure testing between groups, the failure mechanism analysis showed that one 2.4-mm drill hole led to less destabilization of the coracoid than one or two 4-mm drill holes.

CLINICAL RELEVANCE

Techniques with small, 2.4-mm drill holes might decrease the risk of severe iatrogenic fracture complications.

Surgical treatment of acute acromioclavicular joint dislocations: hook plate versus minimally invasive reconstruction

PURPOSE

This study was performed to compare the clinical results of a minimally invasive technique for acute acromioclavicular (AC) joint dislocation repair with the traditional hook plate fixation.

METHODS

Forty-four patients with an acute (within 2 weeks after trauma) complete AC joint separation (35 male, nine female; median age 36.2 years, range 18-56) underwent surgical repair with either a minimally invasive AC joint repair or a conventional hook plate. Functional outcome was evaluated using the Constant-Murley Score (CMS), the TAFT score and the AC joint instability score (ACJI). Radiographic evaluation was performed with bilateral anterior-posterior (a.p.) stress and Alexander views.

RESULTS

All patients were available after a median follow-up of 32 months (range 24-51). There were no significant differences in the mean CMS, Taft score and the ACJI between the two groups. The radiological assessment revealed no significant difference in the coracoclavicular distance. In both groups, a slight loss of reduction was observed. Periarticular ossification was seen in 11 patients of the minimally invasive AC joint repair and eight patients of the hook plate group but this did not affect the final outcome. Hook plates were removed after a median interval of 11.9 weeks (range 10-13).

CONCLUSION

Good clinical results can be achieved with both minimally invasive AC joint repair and hook plate fixation. However, in the hook plate group a second operation is mandatory for plate removal.

LEVEL OF EVIDENCE

III.

Arthroscopically guided navigation for repair of acromioclavicular joint dislocations: a safe technique with reduced intraoperative radiation exposure

Background

Accuracy evaluation of navigated image free placement of double cortical fixation buttons for coracoclavicular tunnel position in comparison to conventional drill guide based placement.

Methods

Twenty-six patients with acute acromioclavicular joint instability were included in this non-randomized cohort study. All patients were treated with a Double- TightRope technique. In 13 cases the conventional drill guide based placement was used (group 1). In 13 patients surgery was performed as a navigated procedure with a fluoro-free optoelectronic system (group 2). The number of coracoclavicular drillings per patient (First pass accuracy; FPA (%)) was documented, the subcoracoidal position of the fixation buttons has been evaluated and graded as “intended position achieved (IPA)” or “intended position not achieved (IPnA)”.

Results

In group 1 drilling had to be repeated in four patients (30.8 %) to achieve proper placement of the subcoracoidal fixation buttons. 100 % first pass accuracy was observed in group 2 (p = 0.03). In group 1, the intended position of the subcoracoid buttons was not achieved (IPnA) in six patients (46.2 %). In group 2 all intended positions were achieved (p = 0.005).

Conclusion

Arthroscopic controlled fluoro-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first pass accuracy in comparison to conventional drill guide based placement. Therefore the navigation enables a precise position of the drill holes, may reduce the risk of an iatrogenic coracoid fracture and migration of fixation devices.

Trial registration

Local institutional review board No. 061-14-10032014

Two-Year Outcomes After Primary Anatomic Coracoclavicular Ligament Reconstruction

PURPOSE

The purpose of this study was to report the clinical and structural outcomes after anatomic coracoclavicular ligament reconstruction (ACCR) with free tendon allografts in patients with grade III and grade V acromioclavicular (AC) joint dislocations.

METHODS

Thirty-one shoulders underwent primary ACCR with tendon allografts for Rockwood grade III and grade V AC joint dislocations. Preoperative data included patient demographic characteristics, injury characteristics, and surgical history, along with American Shoulder and Elbow Surgeons (ASES) scores, Short Form 12 Physical Component Summary (SF-12 PCS) scores, and various pain scales. Outcome measures were also collected a minimum of 2 years postoperatively with the addition of Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores; Single Assessment Numeric Evaluation (SANE) scores; and patient satisfaction. In addition, preoperative and postoperative coracoclavicular distances were analyzed using standard anteroposterior radiographs.

RESULTS

ACCR was performed in 31 patients (31 shoulders) with a mean age of 43.9 years (range, 21 to 71 years). In 7 patients (22.6%) a complication occurred that required a subsequent surgical procedure including graft rupture/attenuation (2), clavicle fractures (2), distal clavicle hypertrophy (2), and adhesive capsulitis (1). Of the remaining 24 patients, 20 (83.3%) had subjective outcome data available after a minimum 2-year follow-up period (mean, 3.5 years; range, 2.0 to 6.2 years). The mean postoperative ASES and SF-12 PCS scores significantly improved when compared with the preoperative baseline values (58.9 v 93.8 for ASES scores [P < .001] and 45.3 v 54.4 for SF-12 PCS scores [P = .007]). At final follow-up, the SANE and QuickDASH scores were 89.1 and 5.6, respectively, with a median patient satisfaction rating of 9 of 10.

CONCLUSIONS

Patients who did not require revision surgery showed excellent postoperative outcome scores: The mean ASES score was 93.8, the mean SANE score was 89.1, and the mean QuickDASH score was 5.6, with a median patient satisfaction rating of 9 of 10. Further study regarding ACCR techniques should focus on decreasing the risks of complications and maintaining reduction of the AC joint.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

[New horizons for minimally invasive treatment of acromioklavikular joint injuries]

BACKGROUND

A novel radiation-free electromagnetic navigation system (ENS) method was developed and the feasibility and accuracy for transklavikular-transkorakoid drilling procedures were evaluated in an experimental setting.

METHODS

In this study ten arthroscopically assisted, electromagnetically navigated transkorakoid-transklavikular drilling procedures with subsequent implantation of two TightRope® (Arthrex, Naples, FL.) devices (anatomical reconstruction) were performed on five human cadavers. Postoperative computed tomography (CT) scan analysis was carried out to determine tunnel placement accuracy. All procedures were performed without fluoroscopy.

RESULTS

The mean overall operation time was 28.5 ± 6.6 min. Successful anatomical tunnel placement was achieved in 98.8 %. During the navigated drilling procedure no misguidance of the drill requiring directional readjustments or restarts occurred. No cortical breaches, fractures or complications occurred.

CONCLUSION

The electromagnetically navigated transkorakoid-transklavikular drilling procedure used in this study demonstrated high targeting accuracy, required no intraoperative x-ray radiation and was associated with no complications.

Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation: a cadaver study

BACKGROUND

Reconstruction of the coracoclavicular ligament functions to restore anatomic alignment of the clavicle and may improve biomechanical function and clinical outcomes. Improper placement of the coracoclavicular tunnel may inherently weaken the coracoid. The purpose of this study was to evaluate the feasibility and accuracy of navigated image-free placement of K-wires for coracoclavicular tunnel position in comparison to conventional drill guide-based placement.

MATERIALS AND METHODS

Eight human shoulder specimens were assigned for conventional technique with a coracoclavicular guide device (group CP) and the paired contralateral side for the navigated procedure (group NP) with an optoelectronic system with a fluoro-free software module. First-pass accuracy (%) and the K-wire trajectory (lateral-center orientation (LC), center-center (CC) orientation and medial-center orientation (MC) were measured.

RESULTS

In all navigated K-wires a 100 % first-pass accuracy was observed. In three of the eight (37.5 %) specimens of the drill guide-based group, drilling had to be repeated. One of them had to be repeated twice, resulting in eight versus twelve drillings for the navigated versus conventional group, respectively (p = 0.021). K-wire trajectory showed an MC orientation in most of the specimen (n = 9, group NP 4, group CP 5).

CONCLUSIONS

Image-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first-pass accuracy in comparison to conventional drill guide-based placement and, therefore, may enable a precise anatomic position of the drill holes and reduce the risk of an iatrogenic coracoid fracture.

Why does minimally invasive coracoclavicular ligament reconstruction using a flip button repair technique fail? An analysis of risk factors and complications

PURPOSE

Aim of the present study was to evaluate the risk factors for the failure of coracoclavicular ligament reconstruction using a flip button repair technique and to analyse complications related to this procedure.

METHODS

Seventy-one patients (3 female, 68 male) underwent surgical treatment using a flip button repair technique for an acute acromioclavicular joint dislocation. The following factors and its impact on clinical and radiographic outcome were assessed: age at trauma, interval between trauma and surgery, degree of displacement (according to Rockwood's classification), coracoid button position, button migration and post-operative appearance of ossifications.

RESULTS

Sixty-three patients were available for follow-up. The overall Constant score was 95.2 points (range 61-100 points) compared to 97 points (range 73-100 points) for the contralateral side (p = 0.05). Nine patients (14.3 %) needed surgical revision. Inappropriate positioning of the coracoid bone tunnel with subsequent button dislocation was the most frequently observed mode of failure (6 cases, 9.5 %). Button migration into the clavicle was associated with loss of reduction (p = 0.02). The patient's age at the time of trauma had a significant impact on the clinical outcome, whereas younger patients achieved better results (p = 0.02). The interval between trauma and surgery did not significantly affect the outcome (n.s.).

CONCLUSION

Good to excellent clinical results can be achieved with the presented surgical technique. The age of the patient at trauma had a significant influence on the functional outcome. Furthermore, placement of the coracoid button centrally under the coracoid base is crucial to prevent failure.

LEVEL OF EVIDENCE

IV.

Chronic acromioclavicular joint dislocations treated by the GraftRope device

BACKGROUND AND PURPOSE

Surgical treatment of chronic acromioclavicular joint dislocations is challenging, and no single procedure can be considered to be the gold standard. In 2010, the GraftRope method (Arthrex Inc., Naples, FL) was introduced in a case series of 10 patients, showing good clinical results and no complications. We wanted to evaluate the GraftRope method in a prospective consecutive series.

PATIENTS AND METHODS

8 patients with chronic Rockwood type III-V acromioclavicular joint dislocations were treated surgically using the GraftRope method. The patients were clinically evaluated and a CT scan was performed to assess the integrity of the repair.

RESULTS AND INTERPRETATION

In 4 of the 8 patients, loss of reduction was seen within the first 6 weeks postoperatively. A coracoid fracture was the reason in 3 cases and graft failure was the reason in 1 case. In 3 of the 4 patients with intact repairs, the results were excellent with no subjective shoulder disability 12 months postoperatively. It was our intention to include 30 patients in this prospective treatment series, but due to the high rate of complications the study was discontinued prematurely. Based on our results and other recent reports, we cannot recommend the GraftRope method as a treatment option for chronic acromioclavicular joint dislocations.

Managing and recognizing complications after treatment of acromioclavicular joint repair or reconstruction

Complications of the acromioclavicular joint injuries can occur as a result of the injury itself, conservative management, or surgical treatment. Fortunately, the majority of acromioclavicular surgeries utilizing modern techniques and instrumentation result in successful outcomes. However, clinical failures do occur with frequency. The ability to identify the causative factor of failures makes revision surgery more likely to be successful. The purposes of this review are to highlight common problems that can occur following acromioclavicular joint surgery and discuss techniques that can be utilized in revision surgery.

Electromagnetic navigation provides high accuracy for transcoracoid-transclavicular drilling

PURPOSE

A novel radiation-free electromagnetic navigation system (ENS)-based method was developed, and its feasibility and accuracy for transclavicular-transcoracoid drilling procedures were evaluated in an experimental setting.

METHODS

Sixteen arthroscopically assisted electromagnetic navigated transcoracoid-transclavicular drilling procedures with subsequent TightRope device implantation were performed on eight human cadavers. Post-operative fluoroscopy and CT-scan analysis were acquired to determine tunnel placement accuracy. Optimal tunnel placement was defined as both the coracoid entry and exit point of the tunnel localized in the centre position of the coracoid base without cortical breach or fracture.

RESULTS

Successful tunnel placement was accomplished in all 16 cases. The mean overall operation time was 30.3 ± 5.0 min. Regarding the coracoid exit point, 15 of 16 tunnels (93.8%) were localized in the desired base-centre position. During the navigated drilling procedure, no misguidance of the drill requiring directional readjustments or restarts occurred. No cortical breach, no fractures and no complications occurred.

CONCLUSIONS

The electromagnetically navigated transcoracoid-transclavicular drilling procedure used in this study demonstrated high targeting accuracy, required no intraoperative radiographs, was associated with no complications and provided user-friendliness.