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

Clavicular tunnel widening after coracoclavicular stabilization surgery: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to (1) estimate the prevalence of clavicular tunnel widening (TW) after coracoclavicular stabilization surgery and its risk factors and (2) assess whether TW is correlated with clavicle fracture or loss of reduction of the acromioclavicular joint (ACJ).

METHODS

In January 2023, 3 electronic databases were searched to collect data on postoperative clavicular TW, its prevalence, magnitude, and correlation with fracture and ACJ loss of reduction. Studies were classified according to the time of surgical intervention, and the clavicular tunnels were categorized by their anatomic location. Mean differences were calculated using a DerSimonian-Laird random-effects model, while binomial outcomes were pooled using the Freeman-Tukey double arcsine transformation. Univariate and multivariate meta-regression analyses were performed to determine the effect of several variables on the proportion of cases with TW.

RESULTS

Fifteen studies (418 shoulders) were included. At the final follow-up, evidence of clavicular TW was found in 70% (95% confidence interval [CI]: 70%-87%; I2 = 89%) of 221 shoulders. Surgeries in acute cases had a lower prevalence of TW (52%) compared to chronic cases (71%) (P < .001). Significant TW was found in the central tunnel (3.2 mm; 95% CI: 1.8-4.6 mm; P < .001; I2 = 72%) for acute injuries and in the medial (1.2 mm; 95% CI: 0.7-1.7 mm; P < .001; I2 = 77%) and lateral (1.5 mm; 95% CI: 0.7-2.3 mm; P < .001; I2 = 77%) tunnels for chronic cases. Single central-tunnel techniques were positively associated with the prevalence of TW (P = .046), while biotenodesis screw fixation was associated with a lower prevalence (P = .004) in chronic cases. Reconstruction of the ACJ ligament complex with tendon grafts or sutures was associated with a higher prevalence of TW (P < .001). Drill sizes between 2.5 and 5 mm were significantly associated with a lower prevalence of TW, regardless of injury chronicity (P = .012). No correlation was found between TW and the loss of ACJ reduction or clavicle fractures.

CONCLUSIONS

This systematic review and meta-analysis explored TW occurrence following coracoclavicular stabilization surgery. TW was observed in 70% of patients at final follow-up, with a higher prevalence in chronic than in acute cases. Modifiable surgical variables, such as single-tunnel tendon graft constructs for acute or chronic injuries and knotted graft procedures for chronic injuries, were significantly associated with TW. Furthermore, the prevalence of TW increased with concomitant surgical treatment of the ACJ ligament complex, and decreased with drill sizes between 2.5 and 5 mm, regardless of lesion chronicity. These surgical variables should be considered when establishing transosseous tunnels for coracoclavicular stabilization. Clavicle fractures and TW mechanisms require further investigation.

Mid-term clinical and sonographic outcomes of minimally invasive acromioclavicular joint reconstruction: mini-open versus arthroscopically assisted

INTRODUCTION

The current literature describes various operative stabilization strategies which achieve good clinical outcomes after acute acromioclavicular joint (ACJ) dislocation. The aim of this study was to compare the mid-term clinical and sonographic treatment outcomes after minimally invasive mini-open and arthroscopic reconstruction.

MATERIALS AND METHODS

We conducted a retrospective two-center study of patients with acute ACJ dislocation. Surgical treatment was performed using either a mini-open approach (MIOP) or an arthroscopic technique (AR). The primary outcome parameters of this study were the sonographically measured acromioclavicular (ACD) and coracoclavicular distances (CCD). Secondary outcome parameters included the Constant-Murley score (CS), range of motion (ROM), postoperative pain scale (VAS), return to daily routine, return to sports, complications, as well as operative revisions.

RESULTS

After a mean follow-up of 29 months, 30 patients were included in this study with an average age of 41.3 ± 14.8 years (MIOP) and 41.2 ± 15.4 years (AR). The sonographic ACD (MIOP 9.11 mm vs. AR 8.93 mm, p = 0.41) and CCD (MIOP 25.08 mm vs. AR 24.36 mm, p = 0.29) distances showed no statistically significant differences. Furthermore, there was no statistically significant difference when compared to the contralateral side (p = 0.42). With both techniques, patients achieved excellent clinical outcome parameters without statistically significant differences in CS (MIOP 95 vs. AR 97, p = 0.11) and VAS (MIOP 1.76 vs. AR 1.14, p = 0.18). The return to daily activity and return to sport rates did not differ. There were neither complications nor revisions in both groups.

CONCLUSION

Both minimally invasive techniques for acute ACJ stabilization achieved excellent clinical and sonographic outcomes without one technique being statistically superior to the other.

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.

Clavicular Tunnel Widening After Acromioclavicular Stabilization Shows Implant-Dependent Correlation With Postoperative Loss of Reduction

PURPOSE

To radiographically describe, quantify, and compare clavicular tunnel widening (cTW) of 2 different types of stabilization devices and investigate a possible correlation between cTW and loss of reduction.

METHODS

In a retrospective analysis of single-center registry data, we compared patients who were treated for an acute AC dislocation (Rockwood types III to V) with either the AC Dog Bone (DB) or low-profile AC (LP) repair systems. On 6-week and 6-month postoperative radiographs, we measured clavicle height and tunnel diameter. We calculated the button/clavicle filling (B/C) ratio to quantify how much of the clavicular tunnel height is covered by the low-profile inlet. The association between B/C ratio and the extent of cTW was defined, and we also compared cTW between treatment groups. Reduction of the AC joint was graded as either stable, partially dislocated or dislocated depending on the AC ratio. A 2-sample t-test was used for comparing cTW progression between the 2 groups. For continuous variables between more than 2 groups, the Kruskal-Wallis test was used.

RESULTS

Of 65 eligible patients, there were 37 and 28 included in the DB and LP groups, respectively. Overall, cTW was conically shaped with transclavicular widening noted in the DB group and cTW developing strictly inferior to the button in the LP group. For both implants, mean maximal cTW was 7.1 mm and located at the inferior cortex; the B/C ratio was not associated with increased inferior cTW (r = -0.23, P = .248). Only LP patients with complete loss of reduction had significantly increased cTW (P = .049).

CONCLUSIONS

Conical-shaped cTW is a common implant-independent phenomenon after AC stabilization using suture-button devices. It occurs only at the suture-bone interface and is less excessive for the LP implant. There is an association between increased cTW and loss of reduction specific to the LP implant only.

LEVEL OF EVIDENCE

Level III, therapeutic study.

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.

Management of Acromioclavicular Joint Injuries: A Historic Account

There has been a rapid evolution in best practice management of acromioclavicular (AC) joint injuries. AP, Zanca, scapular Y, and dynamic axillary radiographic views provide optimal visualization of the joint and may assess for the presence of horizontal AC instability. Severity of AC joint pathology is classified according to the 6-tier Rockwood scoring system. Over 160 surgical techniques have been described for AC joint repair and reconstruction in the last decade; as a result, determining the optimal treatment algorithm has become increasingly challenging secondary to the lack of consistently excellent clinical outcomes.

Iatrogenic instability of the acromioclavicular joint leads to ongoing impairment of shoulder function even following secondary surgical stabilization

PURPOSE

Iatrogenic instability of the acromioclavicular joint (ACJ) following distal clavicle excision (DCE) represents an infrequent pathology. Revision surgery to restore ACJ stability and alleviate concomitant pain is challenging due to altered anatomic relationships. The purpose of this study was to evaluate the used salvage techniques and postoperative functional and radiological outcomes in retrospectively identify patients with a painful ACJ following DCE. We hypothesized that iatrogenic instability leads to ongoing impairment of shoulder function despite secondary surgical stabilization.

METHODS

9 patients with a painful ACJ after DCE (6 men, 3 women, 43.3 ± 9.4 years) were followed up at a minimum of 36 months after revision surgery. Besides range of motion (ROM), strength and function were evaluated with validated evaluation tools including the Constant score and the DASH score (Disability of the Arm, Shoulder and Hand questionnaire), specific AC Score (SACS), Nottingham Clavicle Score (NCS), Taft score and Acromioclavicular Joint Instability Score (AJI). Additionally, postoperative X-rays were compared to the unaffected side, measuring the coracoclavicular (CC) and acromioclavicular (AC) distance.

RESULTS

At follow-up survey (55.8 ± 18.8 months) all patients but one demonstrated clinical ACJ stability after arthroscopically assisted anatomical ACJ reconstruction with an autologous hamstring graft. Reconstruction techniques were dependent on the direction of instability. The functional results demonstrated moderate shoulder and ACJ scores with a Constant Score of 77.3 ± 15.4, DASH-score of 51.2 ± 23.4, SACS 32.6 ± 23.8, NCS 77.8 ± 14.2, AJI 75 ± 14.7 points and Taft Score 7.6 ± 3.4 points. All patients stated they would undergo the revision surgery again. Mean postoperative CC-distance (8.3 ± 2.8 mm) did not differ significantly from the contralateral side (8.5 ± 1.6 mm) (p > 0,05). However, the mean AC distance was significantly greater with 16.5 ± 5.8 mm compared to the contralateral side (3.5 ± 1.9 mm) (p = 0.012).

CONCLUSION

Symptomatic iatrogenic ACJ instability following DCE is rare. Arthroscopically assisted revision surgery with an autologous hamstring graft improved ACJ stability in eight out of nine cases (88.9%). However, the functional scores showed ongoing impairment of shoulder function and a relatively high overall complication rate (33.3%). Therefore, this study underlines the importance of precise preoperative indication and planning and, especially, the preservation of ACJ stability when performing AC joint resection procedures.

LEVEL OF EVIDENCE

Case series, LEVEL IV.

No correlation exists between coracoid tunnel widening and loss of reduction after arthroscopic acromioclavicular fixation using tightrope system

PURPOSE

To detect the widening of the tunnel of the coracoid process after arthroscopic fixation of acute acromioclavicular joint (ACJ) dislocation using the TightRope system and its correlation with loss of reduction and functional scores.

METHODS

From 2016 to 2018, a prospective study was performed on twenty-three patients with acute grade III-V ACJ dislocation. Arthroscopic TightRope repair of the ACJ was performed. Coracoid tunnel widening was measured by CT, and the coracoclavicular distance was measured on the radiographs immediately postoperatively and at 12 months. The Constant Shoulder Score, Oxford Shoulder Score, Nottingham Clavicle Score and Visual analog scale were used as outcome measures at 12 months.

RESULTS

The coracoid tunnel diameter to horizontal coracoid diameter ratio increased from 22.8 ± 3.7% immediately postoperatively to 38.5 ± 5.5% at 12 months (p < 0.001). The coracoclavicular (CC) distance showed an increase from a mean of 10.8 ± 1.7 mm to a mean of 11.8 ± 2.5 at 12 months (p < 0.001). There was no correlation between the increase in the coracoclavicular distance and the patients' functional clinical scores or coracoid tunnel widening.

CONCLUSION

Coracoid tunnel widening and radiological loss of reduction occur after arthroscopic fixation of acute ACJ dislocation with the TightRope system. However, they do not correlate with each other or with the functional scores of the patient.

LEVEL OF EVIDENCE

Level IV.

Surgical management of acute, high-grade acromioclavicular joint separations: a systematic review

Background

While a number of treatment options exist for repair of acute, high-grade acromioclavicular joint (ACJ) separation, none have emerged as the standard of care. The purpose of this study was to systematically review the literature on surgical treatment of acute, high-grade (Rockwood grades III-V) ACJ separations in order to compare outcomes between direct fixation and tendon graft ligament reconstruction.

Methods

A systematic review of the literature evaluating outcomes for acute ACJ separation treatment with direct fixation or free biologic tendon graft reconstruction was performed. The following databases were examined: the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (1980-2021), and Embase (1980-2021). Studies were included if they reported a mean time to surgery as <6 weeks, contained >10 patients with a minimum 1-year follow-up, and reported clinical or radiographic outcomes.

Results

A total of 52 studies met the inclusion criteria. Seven studies reported outcomes following tendon graft ligament reconstruction (n = 128 patients). There were multiple methods of direct fixation. Thirty-three studies utilized suture button constructs (n = 1138), 16 studies used hook plates (n = 567), 2 studies used coracoclavicular screws (n = 94), 2 studies used suture fixation (n = 93), 2 studies used suture anchor (n = 55), 2 studies used suture cerclage fixation (n = 87), 1 used single multistrand titanium cable (n = 24), and 1 used K wire (n = 11). The mean follow-up Constant scores ranged from 77.5 to 97.1 in the fixation group compared to 90.3-96.6 in the tendon graft group. The mean visual analog scale scores ranged from 0 to 4.5 in the fixation group and 0.1-1 in the tendon graft group. Net CC distance ranged from 17.5 to 3.6 mm in the fixation group and 7.4-4 mm in the tendon graft group. The revision rates ranged from 0.0% to 18.18% in the direct fixation group and 5.88%-17% in the tendon graft group.

Conclusion

Direct fixation and tendon graft reconstruction for management of acute, high-grade ACJ separations have similar patient subjective and radiographic outcomes, as well as complication and revision rates at a minimum 1-year follow-up.

Implant-dependent behavior of tunnel widening and clavicular button migration after arthroscopic-assisted treatment of acromioclavicular joint instabilities

INTRODUCTION

Despite ongoing discussions for the previous few decades, there is still no consensus regarding the optimal surgical technique for acromioclavicular joint instabilities. The purpose of this study was to determine the impact of various implant materials following arthroscopically assisted stabilization of acromioclavicular joint instabilities on tunnel widening and implant migration. We hypothesized an implant-dependent behavior for tunnel widening and implant migration with differences when comparing acute and chronic acromioclavicular joint instabilities.

METHODS

This study compared 105 patients with acromioclavicular joint instabilities that were managed operatively with coracoclavicular double button constructs. Two of the groups containing acute cases were treated with either a double button construct with a wire (TR) or a tape (D) as a central pillar. The two groups with chronic cases were either treated with a wire (T+) or tape D+ as a central pillar and additional hamstring tendon augmentation (+). One central transclavicular-transcoracoidal drill channel was made in the acute cases, while additional medial and lateral drill channels to augment the central pillar with the hamstring tendon were made. The central drill channel in all cases and the medial/lateral drill channels in chronic cases were subsequently radiologically analyzed immediately postoperatively and at follow-up. Following this, additional radiological analysis of the implant migration of the clavicular button took place.

RESULTS

All groups showed significant tunnel widening of the central drill channel at follow-up (p ≤ 0.001). The TR+ technique demonstrated significant widening in both the medial (p ≤ 0.001) and lateral (p ≤ 0.001) drill channels. The D and D+ group displayed significant higher rates of clavicular button migration to a cortical and intraosseous level (p ≤ 0.002).

CONCLUSION

Tunnel widening and implant migration following arthroscopically assisted management of acromioclavicular joint instabilities are dependent on the chosen implant. The stable tape showed a significantly increased degree of tunnel widening with respect to the central drill channel in comparison with the wire. In contrast, a higher degree of load capacity of the tape ultimately favors a protected intraosseous graft healing for chronic cases, which leads to less tunnel widening of the medial and lateral drill channel. Finally, the D/D+ implant groups showed higher rates of implant migration due to lower contact surface area of the implant at the upper clavicular cortex.

LEVEL OF EVIDENCE IV

Acromioclavicular joint suture button repair leads to coracoclavicular tunnel widening

PURPOSE

Biomechanical evaluation of three different suture button devices used in acromioclavicular joint repair and analysis of their effect on post-testing tunnel widening.

METHODS

Eighteen human shoulder girdles were assigned into three groups with a similar mean bone mineral density. Three different single-tunnel acromioclavicular repair devices were tested: (1) AC TightRope^® with FiberWire; (2) AC Dog Bone^™ Button with FiberTape; (3) Low Profile AC Repair System. Biomechanical testing was performed simulating the complex movement of the distal clavicle as follows. A vertical load of 80 N was applied continuously. The rotation of the clavicle about its long axis was set at 10° anterior and 30° posterior for 2500 cycles at 0.25 Hz. The horizontal translation of the clavicle was set at 6 mm medial and 6 mm lateral for 10,000 cycles at 1 Hz. The coracoclavicular distance was measured before and after testing. After testing, each sample underwent micro-CT analysis. Following 3D reconstruction, the area of the bone tunnels was measured at five defined cross sections.

RESULTS

In TightRope^® and Dog Bone^™ groups, all samples completed testing, whereas in the Low Profile group, three out of six samples showed system failure. The mean absolute difference of coracoclavicular distance after testing was significantly greater in the Low Profile group compared to TightRope^® and Dog Bone^™ groups (4.3 ± 1.3 mm vs 1.9 ± 0.7 mm vs 1.9 ± 0.8 mm; p = 0.001). Micro-CT analysis of the specimens demonstrated significant tunnel widening in the inferior clavicular and superior coracoid regions in all three groups (p < 0.05).

CONCLUSION

Significant tunnel widening can be observed for all devices and is primarily found in the inferior parts of the clavicle and superior parts of the coracoid. The Low Profile AC Repair System showed inferior biomechanical properties compared to the AC TightRope^® and AC Dog Bone^™ devices. Therefore, clinicians should carefully select the type of acromioclavicular repair device used and need to consider tunnel widening as a complication.

Concomitant coracoid base fracture and acromioclavicular joint disruption: A series of patients treated with a clavicle hook plate and review of the literature

INTRODUCTION

Concomitant acromioclavicular joint (ACJ) disruptions with coracoid base fractures are rare high energy injuries. The management of these injuries can be challenging. The aim of this study is to assess the functional and radiographic outcomes of a retrospective case series of patients presenting with concomitant ACJ and coracoid base injuries managed with a clavicle hook plate with subsequent hardware removal at a later stage.

METHODS

Six patients were identified for inclusion in the study. Radiographic and clinical data were available which allowed for collection of demographic information as well as classification of the fractures. Telephone consultation with patients allowed for collection of functional scores which included the Oxford shoulder score (OSS), QuickDASH (Q-DASH), Euroqol-5 Dimension (EQ-5D) and the SF-12 score.

RESULTS

All patients were male with a mean age of 39.8 years and a median follow-up period of 34 months. All patients underwent a successful operative procedure with a median time to union of 3.75 months. Good functional outcomes were reported by all patients: mean OSS 45.0, mean Q-DASH 4.8, mean EQ-VAS 82.8 and encouraging SF-12 scores (mean PCS 56.0, mean MCS 56.4).

CONCLUSION

The use of a lateral clavicle hook plate can achieve good healing and functional outcomes when managing patients with acromioclavicular joint disruptions associated with a coracoid base fracture.

A modified method of augmented distal clavicle fracture osteosynthesis with a Fibertape coracoclavicular cerclage

BACKGROUND

Unstable distal clavicles experience high non-union rates, prompting surgeons to recommend surgery for more predictable outcomes. There is a lack of consensus on the optimal method of surgical fixation, with an array of techniques described in the literature. We describe an alternative method of fixation involving the use of a distal clavicular anatomical locking plate with Fibertape cerclage augmentation in our series of patients.

METHODS

Nine patients (8 males and 1 female), with a mean age of 36 years, who sustained unstable fracture of the distal clavicle in our institution were treated with our described technique. Postoperative range of motion, functional and pain scores, and time to radiographic union were measured over a mean follow-up period of 10 months. Incidences of postoperative complications were also recorded.

RESULTS

At the last patient consult, the mean visual analog scale score was 0.88±0.35, with a mean Disabilities of the Arm, Shoulder, and Hand (DASH) score of 1.46±0.87 and American Shoulder and Elbow Surgeons (ASES) score of 94.1±3.57. The mean range of motion achieved was forward flexion at 173°±10.6°, abduction at 173°±10.6°, and external rotation at 74.4°±10.5°. All patients achieved internal rotation at a vertebral height of at least L2 with radiographical union at a mean of 10 weeks. No removal of implants was required.

CONCLUSIONS

Our described technique of augmented fixation of the distal clavicle is effective, produces good clinical outcomes, and has minimal complications.

Addition of Allograft and Acromioclavicular Cerclage Improves Outcomes of Arthroscopic-Assisted Reconstruction of Acromioclavicular Separation With a Single Coracoclavicular Tunnel

Objective

The purpose of this study was to prospectively evaluate the functional outcome and complications of unstable acromioclavicular (AC) joint separations repaired with a single coracoclavicular tunnel utilizing an arthroscopic-assisted curved button technique.

Methods

Thirty-five patients with a minimum of 12 months follow-up underwent arthroscopic-assisted AC joint reconstruction with suspensory button and 2 mm suture tape fixation using 3 mm tunnels. Functional outcome scores were analyzed preoperatively and at final follow-up with all complications noted.

Results

Comparing preoperative to postoperative values, all functional outcome scores improved. Three of the 16 (19%) patients that had a supplementary graft looped around the undersurface of the coracoid demonstrated loss of reduction compared to eight of the 19 (42%) that were treated with button and suture fixation alone (p = .138). No loss of reduction occurred in the subset of patients with AC joint supplementation. One (3%) patient sustained a distal clavicle fracture.

Conclusion

Arthroscopic-assisted AC joint reconstruction with a suspensory button construct demonstrates improved clinical outcomes with high patient satisfaction. While loss reduction remains problematic, smaller bone tunnels appear to lead to a low rate of iatrogenic fractures. The addition of a free tendon graft, as well as AC cerclage, appears to minimize loss of reduction.

Treatment of Failed Coracoclavicular Ligament Reconstructions: Primary Acromioclavicular Ligament and Capsular Reconstruction and Revision Coracoclavicular Ligament Reconstruction

Acromioclavicular (AC) joint dislocations are a common injury affecting 2 of every 10,000 people in the general population and comprise 9% to 12% of all injuries to the shoulder. Most injuries occur through contact activity, which drives the acromion inferiorly with the clavicle remaining in its anatomic position, initiating a cascade of injury propagating from the AC ligament followed by failure of the coracoclavicular ligaments. Many techniques have been described for AC joint injuries, without a consensus gold standard. The revision setting offers even less consensus on treatment options and countless difficulties for surgeons. There have been more than 60 described procedures regarding AC and coracoclavicular ligament reconstructions, with significant controversy regarding the optimal intervention for each injury. When these techniques fail, it is important to pinpoint the mechanism of failure to construct a successful plan for revision. The purpose of this Technical Note is to describe our preferred method of primary AC and revision coracoclavicular reconstruction using a combination of autograft and allograft semitendinosus as well as TightRope fixation.

Arthroscopic-Assisted Acromioclavicular Joint Reconstruction

There are many documented techniques for the surgical treatment of a chronic acromioclavicular (AC) joint reconstruction, but unfortunately, there is no gold standard. Treatment options include hook plates, allograft reconstruction, and suture fixation, among many others.

This technique is an innovative method for looping the allograft around the coracoid and clavicle and using the hook plate for fixation. This avoids any drilling within the clavicle or coracoid, therefore decreasing the risk of fracture and ensuring the reduction of the AC joint.

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.

Anatomical versus non-anatomical configuration of double coraco-clavicular tunnel technique in acromioclavicular joint reconstruction

PURPOSE

Horizontal instability is a common problem after acromioclavicular joint injuries. The aim of this study was to evaluate if there is a difference regarding horizontal stability between an anatomical and a non-anatomical configuration of the double tunnel coraco-clavicular ligament reconstruction of the acromioclavicular joint.

METHODS

Thirteen acromioclavicular joints of human cadaveric shoulders in ethanol-glycerin fixation were included in the study and underwent cyclic anterior and posterior translational testing at a load of 70 N using an electromechanical uniaxial testing machine. The shoulders were randomly assigned to the following groups: double coraco-clavicular tunnel technique in an anatomical configuration (DCTa) and double coraco-clavicular tunnel technique in an inverse configuration of the anatomical position (DCTb). The dislocation was recorded with a 3D optical measuring system.

RESULTS

The total horizontal displacement (p₁₀ = 0.0221; p₅₀₀₀ = 0.082) was significantly higher for the non-anatomical reconstruction (DCTb) compared to the anatomical reconstruction (DCTa) after every measured amount of cycles. The increase in displacement for DCTb group was overall higher than the increase in displacement for DCTa group but without significance.

CONCLUSION

Reconstruction of the CC ligaments in an anatomical configuration with two suture devices results in a significantly higher stability of the AC joint in the horizontal plane than reconstruction of the CC ligaments in a non-anatomical configuration. Based on the results of this biomechanical in vitro study, the use of a double coraco-clavicular reconstruction should focus on an anatomically correct position of the suture devices.

Radiographic and clinical characterization of coracoid fractures: a retrospective cohort analysis

PURPOSE

Coracoid fracture is a rare injury. The aim of this study is to present the demographics, clinical and radiologic characteristics, and outcomes of coracoid fracture in a cohort of 32 patients.

METHODS

We queried our institutional electronic medical record database (years 2012-2020) to identify patients with coracoid fractures using specific International Classification of Disease-10 codes. Demographic data, injury details including mechanism of injury and associated injuries, imaging performed, and treatment outcomes were obtained from retrospective chart review. A radiologist reviewed all available imaging studies (radiographs/CT/MRI) and classified the fractures according to Ogawa and Eyres classifications. Missed diagnoses were determined by comparing initial imaging reports with the follow-up imaging obtained in the office.

RESULTS

Thirty-two patients with coracoid fractures were identified during the study period. Sixteen fractures (50%) occurred in the setting of low-energy trauma. Twelve fractures were missed on initial radiographs, and diagnosis with three-view radiographs (AP, scapular-Y and axillary) was 88% compared to 33% (p < 0.03) with two views (AP, scapular-Y). The majority of fractures were non-displaced (94%), and 56% were Ogawa Type-II fractures. Associated injuries were seen in 81% of patients. Most fractures (94%) were treated without surgery with excellent outcomes.

CONCLUSION

Coracoid fractures continue to be a rare injury. In contrast to previous studies, in this case series of 32 patients, half of the fractures were associated with low-energy trauma, which correlated with higher percentage of non-displaced fractures and Ogawa Type-II fractures. Addition of the axillary view in the trauma radiographic series significantly improved the initial fracture detection rate.

LEVEL IV

Retrospective study.

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.

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.

Clinical Outcome of a Modified Coracoid Tunnel-Free Coracoclavicular Sling Technique With Remnant Preservation for the Treatment of High-Grade Acromioclavicular Joint Separation: A Report of 48 Cases With 2 to 5 Years of Follow-up

BACKGROUND

High-grade acromioclavicular (AC) joint separation injuries (Rockwood type IV or V) are surgically indicated because of complete disruption of the AC and coracoclavicular (CC) ligaments, leading to instability and pain. In surgical techniques that require a suspensory system, coracoid tunnel-related complications are not uncommon.

PURPOSE

To report subjective and objective clinical outcomes and complication rates of a modified coracoid tunnel-free CC sling technique combined with CC ligament remnant preservation for a minimum 2-year follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between January 2014 and January 2017, we prospectively enrolled patients who underwent a modified CC sling technique performed by 1 senior surgeon using the AC TightRope System in a coracoid tunnel-free fashion. The CC distance (CCD) and Rockwood AC joint classification were evaluated on radiographs preoperatively, immediately postoperatively, and at the final follow-up. The visual analog pain score, range of motion, American Shoulder and Elbow Surgeons score, Constant-Murley score, and University of California Los Angeles score were recorded preoperatively and at the final follow-up.

RESULTS

In total, 48 of 54 patients (88.9%) were included for the evaluation with a mean ± SD follow-up of 39.3 ± 8.9 months (range, 24.7-64.3 months). The CCD was significantly decreased from 22.7 ± 4.2 to 9.8 ± 2.3 mm (P < .01) immediately after surgery and to 11.2 ± 1.8 mm (P < .01) at final follow-up. At the final follow-up, the side-to-side difference of CCD was 3.5 ± 0.6 mm. Compared with the preoperative level, all subjective evaluations were significantly improved at the final follow-up. We observed that 4 of the 48 patients (8.3%) had a loss of reduction at the final follow-up, but no pain or instability was documented. Further, no coracoid-related complication or other complications were recorded.

CONCLUSION

The coracoid tunnel-free CC sling technique using the AC TightRope System combined with CC ligament remnant preservation demonstrated significant improvement regarding both clinical and radiological outcomes, with a reduction loss rate of 8.3%. It is a safe method that could achieve satisfactory result without any coracoid drilling-related complications.

Acromioclavicular joint reconstruction implants have differing ability to restore horizontal and vertical plane stability

PURPOSE

Persistent acromioclavicular joint (ACJ) instability following high grade injuries causes significant symptoms. The importance of horizontal plane stability is increasingly recognised. There is little evidence of the ability of current implant methods to restore native ACJ stability in the vertical and horizontal planes. The purpose of this work was to measure the ability of three implant reconstructions to restore native ACJ stability.

METHODS

Three groups of nine fresh-frozen shoulders each were mounted into a robotic testing system. The scapula was stationary and the robot displaced the clavicle to measure native anterior, posterior, superior and inferior (A, P, S, I) stability at 50 N force. The ACJ capsule, conoid and trapezoid ligaments were transected and the ACJ was reconstructed using one of three commercially available systems. Two systems (tape loop + screw and tape loop + button) wrapped a tape around the clavicle and coracoid, the third system (sutures + buttons) passed directly through tunnels in the clavicle and coracoid. The stabilities were remeasured. The data for A, P, S, I stability and ranges of A-P and S-I stability were analyzed by ANOVA and repeated-measures Student t tests with Bonferroni correction, to contrast each reconstruction stability versus the native ACJ data for that set of nine specimens, and examined contrasts among the reconstructions.

RESULTS

All three reconstructions restored the range of A-P stability to that of the native ACJ. However, the coracoid loop devices shifted the clavicle anteriorly. For S-I stability, only the sutures + buttons reconstruction did not differ significantly from native ligament restraint.

CONCLUSIONS

Only the sutures + buttons reconstruction, that passed directly through tunnels in the clavicle and coracoid, restored all stability measures (A, P, S, I) to the native values, while the tape implants wrapped around the bones anteriorised the clavicle. These findings show differing abilities among reconstructions to restore native stability in horizontal and vertical planes. (300 words).

Minimum 10-Year Outcomes After Revision Anatomic Coracoclavicular Ligament Reconstruction for Acromioclavicular Joint Instability

Background:

Revision surgery in cases of previously failed primary acromioclavicular (AC) joint stabilization remains challenging mainly because of anatomic alterations or technical difficulties. However, anatomic coracoclavicular ligament reconstruction (ACCR) has been shown to achieve encouraging biomechanical, clinical, and radiographic short-term to midterm results.

Purpose:

To evaluate the clinical and radiographic long-term outcomes of patients undergoing revision ACCR after failed operative treatment for type III through V AC joint injuries with a minimum 10-year follow-up.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective chart review was performed on prospectively collected data within an institutional shoulder registry. Patients who underwent revision ACCR for type III through V AC joint injuries between January 2003 and December 2009 were analyzed. Clinical outcome measures included the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and Single Assessment Numeric Evaluation (SANE). The coracoclavicular distance (CCD) was measured for radiographic analysis immediately postoperatively and at last postoperative follow-up.

Results:

A total of 8 patients with a mean age at the time of surgery of 44.6 ± 10.6 years and a mean follow-up of 135.0 ± 17.4 months (range, 120-167 months) were eligible for inclusion in the study. The time from initial AC joint stabilization until revision surgery was 10.2 ± 12.4 months (range, 0.5-36 months); 62.5% of the patients had undergone more than 2 previous AC joint surgical procedures. The ASES score improved from 43.9 ± 22.4 preoperatively to 80.6 ± 28.8 postoperatively (P = .012), the SST score improved from 4.4 ± 3.6 preoperatively to 11.0 ± 2.2 postoperatively (P = .017), and the SANE score improved from 31.4 ± 27.3 preoperatively to 86.9 ± 24.1 postoperatively (P = .018) at final follow-up. There was no significant difference in the CCD (P = .08) between the first (7.6 ± 3.0 mm) and final (10.6 ± 2.8 mm) radiographic follow-up (mean, 50.5 ± 32.7 months [range, 18-98 months]).

Conclusion:

Patients undergoing revision ACCR after failed operative treatment for type III through V AC joint injuries maintained significant improvement in clinical outcomes at a minimum 10-year follow-up.

Novel Double Endobutton Technique Combined with Three-Dimensional Printing: A Biomechanical Study of Reconstruction in Acromioclavicular Joint Dislocation

Objective

To reconstruct the acromioclavicular (AC) joint using an adjusted closed‐loop double Endobutton technique via a guiding locator that was applied using three‐dimensional (3D) printing technology. At the same time, the reliability and safety of the novel double Endobutton (NDE) were tested by comparing the biomechanics of this technique with the TightRope (TR) approach.

Methods

This retrospective study was conducted between January 2017 and January 2019. The Department of Anatomy at Southern Medical University obtained 18 fresh‐frozen specimens (8 left and 10 right; 12 men and 6 women). First, the guiding locators were applied using 3D printing technology. After preparation of materials, specimens were divided into an NDE group, a TR group, and a normal group. In the NDE and TR groups, the navigation module was used to locate and establish the bone tunnels; after that, the NDE or TR was implanted. However, the Endobuttons were fixed while pressing the distal clavicle downwards and the length of the loop could be adjusted by changing the upper Endobutton in the NDE group while the suture button construct was tensioned and knotted after pressing down the distal clavicle in the TR. Finally, load testing in anterior–posterior (AP), superior–inferior (SI), and medial–lateral (ML) directions as well as load‐to‐failure testing in the SI direction were undertaken to verify whether the NDE or TR had better biomechanics.

Results

In the load testing, the displacements of the NDE and TR groups in the AP, SI, and ML direction were significantly shorter than those of the normal group (P < 0.05). In the load‐to‐failure testing, the ultimate load of the NDE and TR groups had significantly higher increases than the normal group (722.16 ± 92.04 vs 564.63 ± 63.05, P < 0.05; 680.20 ± 110.29 vs 564.63 ± 63.05, P < 0.05). However, there was no statistically significant difference between the two techniques for these two tests (P > 0.05). In the NDE group, four of six failures were a result of tunnel fractures of the coracoid, while two of six were due to suture breakage. In the TR, three failures were due to coracoid tunnel fractures, one was a result of a clavicle tunnel fracture, and the rest were due to suture breakage. In the normal group, half of the failures were a result of avulsion fractures of the conical ligament at the point of the coracoid process, and the other three were due to rupture of the conical ligament, fracture of the distal clavicle, and fracture of the scapular body.

Conclusion

As for the TR technique, the stability and strength of the AC joint were better in patients who underwent reconstruction using the NDE technique than in the intact state.

A Comparison of 3 Fixation Strategies in the Treatment of Neer Type IIB Distal Clavicle Fractures

OBJECTIVES

To compare the stability of NT2B clavicle fractures fixed with either a hook plating (HP), Superior Plating with Suture Augmentation (SPSA), or dual orthogonal plating (DP) with the hypothesis that DP would provide increased multiplanar stability across NT2B fractures.

METHODS

NT2B distal clavicle fractures were created in cadaveric specimens and fixed using (1) HP, (2) SPSA, or (3) DP. Specimens were cyclically loaded in 3 different planes of motion: (1) anteroposterior (AP), (2) superior-inferior, and (3) axial rotation while displacement was continually recorded. Afterward, a superiorly directed load was applied to the clavicle. Load to failure, stiffness, and mode of failure were recorded.

RESULTS

During AP loading, clavicles fixed with a DP had significantly lower mean posterior displacement compared to those fixed with SPSA at every 100-cycle interval of testing, P < 0.01. During inferior-superior loading, specimens fixed with a DP had less superior displacement than specimens fixed with an HP and SPSA, reaching significance at the 500-700 cycles of testing. There was no significant difference in axial rotation stability or load to failure between the 3 fixation techniques.

CONCLUSIONS

Orthogonally placed minifragment plates provide improved stability against anterior displacement with no significant difference in superior stability, axial rotational stability, stiffness, or load to failure. Further clinical studies are needed to confirm the long-term stability of dual plating and determine the risks and benefits of this novel method of distal clavicle fixation.

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.

The importance of biomechanical properties in revision acromioclavicular joint stabilization: a scoping review

PURPOSE

Treatment of failed primary reconstruction of the unstable acromioclavicular (AC) joint remains challenging for orthopaedic surgeons. When approaching revision cases, the reason for failure has to be precisely identified. The purpose of this manuscript was to perform a critical review of the literature regarding treatment options for failed AC joint stabilization techniques and to provide a treatment algorithm for salvage procedures.

METHODS

A thorough search included electronic databases for articles published up to April 15th, 2019. Inclusion criteria were set as (1) studies that reported on clinical outcomes following surgical or conservative treatment of AC joint dislocation; (2) studies reporting on failure or complications of primary treatment; (3) chronic instabilities caused by delayed or secondary treatment as well as (4) revision and salvage procedures.

RESULTS

The search strategy identified a total of 3269 citations. The final dataset comprised 84 studies published between 1954 and 2019. A total of 5605 patients (9.63% females) were involved with a mean age of 34.5 years. Overall, complication rates varied between 5 and 88.9% in patients with AC joint instability.

CONCLUSION

In the current literature, evidence for treatment of revision AC joint instability is still lacking, however, surgical treatment continues to evolve. The importance of failure analysis and clinically relevant algorithms were highlighted in this review. Adequately restoring native joint biomechanics is needed for ensuring an optimal healing environment that will translate into patient satisfaction and long-term stability.

LEVEL OF EVIDENCE

V.

Arthroscopically assisted acromioclavicular joint stabilization leads to significant clavicular tunnel widening in the early post-operative period

PURPOSE

Arthroscopically assisted acromioclavicular joint (ACJ) stabilization techniques use bone tunnels in the clavicle and coracoid process. The tunnel size has been shown to have an impact on the fracture risk of clavicle and coracoid. The aim of the present study was to radiographically evaluate the alterations of the clavicular tunnel size in the early post-operative period. It was hypothesized that there would be a significant increase of tunnel size.

METHODS

Twenty consecutive patients with acute high-grade ACJ (Rockwood type IV-V) injury underwent arthroscopic-assisted ACJ stabilization. The median age of the patients was 40 (26-66) years. For all patients, a single tunnel button-tape construct was used along with an additional ACJ tape cerclage. Radiologic measurements were undertaken on standardized Zanca films at two separate time points, immediate post-operative examination (IPO) and at late post-operative examination (> 4 months; LPO). The LPO radiographs were taken at a median follow-up period of 4.5 (3-6) months. Clavicular tunnel width (CT) and coracoclavicular distance (CCD) were measured using digital calipers by two independent examiners and the results are presented as median, range, and percentage.

RESULTS

The median CCD increased significantly from 9.5 (8-13) mm at IPO to 12 (7-20) mm at LPO (p < 0.05). Median tunnel size showed significant difference from 3 (3-4) mm at IPO to 5 (4-7) mm at LPO (p < 0.05). Despite a significant increase of 2 mm (66.6%) of the initial tunnel size, there was no correlation between tunnel widening and loss of reduction.

CONCLUSION

Arthroscopic ACJ stabilization with the use of bone tunnels led to a significant increase of clavicular tunnel size in the early post-operative period. This phenomenon carries a higher fracture risk, especially in high-impact athletes, which needs to be considered preoperatively.

LEVEL OF EVIDENCE

IV.

Clavicle and coracoid process periprosthetic fractures as late post-operative complications in arthroscopically assisted acromioclavicular joint stabilization

PURPOSE

Arthroscopic-assisted stabilization surgery for acute acromioclavicular joint (ACJ) disruption shows excellent and reliable clinical outcomes. However, characteristic complications such as fracture of the clavicle and coracoid have been reported to occur during the early post-operative period. The main goal of this study was to highlight the occurrence of fractures as a late post-operative complication. The secondary goals were to describe possible fracture morphologies and treatment outcomes.

METHOD

Patient records from a single surgery centre were searched for all patients presenting with late fracture complication following arthroscopically assisted acromioclavicular stabilization. Medical reports including the operative notes and pre- and post-operative X-rays were reviewed. A telephone interview was conducted with each patient to access the American Shoulder and Elbow Surgeons shoulder score.

RESULTS

A total of four patients presented with late fracture complication following arthroscopic-assisted ACJ stabilization surgery. All patients were males and presented following trauma at a median duration of 19.5 months after the index surgery. Fracture morphology differed between patients; the treatment was conservative in three patients, while one patient underwent osteosynthesis.

CONCLUSION

Traumatic peri-implant fractures can occur, even 2 years after arthroscopically assisted ACJ reconstruction. This needs to be considered when planning for surgical intervention in acute ACJ disruption, especially in a high-risk population.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

The Diagnosis and Treatment of Acute Dislocation of the Acromioclavicular Joint

BACKGROUND

The acromioclavicular joint (ACJ) is one of the more common sites of shoulder girdle injury, accounting for 4-12% of all such injuries, with an incidence of 3-4 cases per 100 000 persons per year in the general population. Current topics of debate include the proper standard diagnostic evaluation, the indications for surgery, and the best operative method.

METHODS

This review is based on publications retrieved by a selective literature search.

RESULTS

Mechanical trauma of the ACG can tear the ligamentous apparatus that holds the acromion, clavicle, and coracoid process together. Different interventions are indicated depending on the nature of the injury. In recent years, the horizontal component of the instability has received more attention, in addition to its vertical component. Persistent instability can lead to chronic, painful limitation of shoulder function, particularly with respect to working above the head. Surgical stabilization is therefore recommended for high-grade instability of Rockwood types IV and V. Modern reconstruction techniques enable selective vertical and horizontal treatment of the instability and have been found superior to traditional methods, particularly in young athletes. Arthroscopic techniques are advantageous because they are less invasive, do not require removal of implanted material, and afford the opportunity to diagnose any accompanying lesions definitively and to treat them if necessary. Surgery for acute injuries should be performed within three weeks of the trauma. For chronic injuries, additional tendon augmentation is now considered standard treatment.

CONCLUSION

High-grade ACJ instability is a complex and significant injury of the shoulder girdle that can cause persistent pain and functional impairment. The state of the evidence regarding its optimal treatment is weak. Large-scale, prospective, randomized comparative studies are needed in order to define a clear standard of treatment.

Acromioclavicular Joint Injuries: Evidence-based Treatment

Injuries to the acromioclavicular (AC) joint are common in the athletic patient population. Most AC joint injuries occur in young males, typically from a direct fall onto the superior aspect of the shoulder when the arm is adducted. Numerous publications describing joint anatomy and biomechanics, surgical techniques for reconstruction, and rehabilitation protocols are available to guide treatment strategies for injuries to the AC joint. Treatment is typically nonsurgical for type I and II injuries and surgical for type IV and VI injuries. Controversy surrounds the indications for nonsurgical versus surgical treatment of type III and V injuries. Multiple surgical techniques have been described, including coracoclavicular (CC) screw fixation, coracoacromial ligament transfer, and numerous methods of CC ligament reconstruction. Anatomic CC ligament reconstruction can be performed either open or arthroscopically, with and without graft augmentation. This article will discuss clinically relevant anatomy and biomechanical properties of the AC joint and will review decision-making principles and treatment options for common AC joint injuries. An updated summary of clinical outcomes after AC joint treatment will also be presented.

Challenges in Treating Acromioclavicular Separations: Current Concepts

Injuries to the acromioclavicular joint constitute approximately 3.2% of shoulder injuries. Although the overall goal of treatment continues to be return to activity with a pain-free shoulder, the treatment of acromioclavicular joint separations has been fraught with conflict since the earliest reports in both ancient and modern literature. Accurate diagnosis and classification are important to determine the optimal treatment. Nonsurgical therapy remains the mainstay for treatment of low- and most mid-grade injuries, although recent biomechanical and biokinetic data might suggest that patients are more affected than traditionally thought. High-grade injuries often necessitate surgical intervention, although little consensus exists on the timing or technique. New surgical techniques continue to evolve as more biomechanical data emerge and kinematic understanding improves. Challenges associated with management of this injury abound from diagnosis to reconstruction.

Arthroscopy-assisted Treatment of Displaced Distal Clavicle Fractures Utilizing Curved Buttons and Suture Tape With a Single Coracoclavicular Tunnel

BACKGROUND

Distal third clavicle fractures are associated with high rates of nonunion. Acceptable healing rates have been reported; however, complications and the need for additional procedures are a concern. The purpose of this study was to evaluate the functional outcomes and healing rates of an arthroscopy-assisted technique for fixation of unstable distal third clavicle fractures.

METHODS

Seven patients presenting to a single surgeon with displaced distal clavicle fractures were included. A curved suspensory button and suture tape construct with a single coracoclavicular tunnel was used. Visual Analog Scale, American Shoulder and Elbow Surgeons scores, Simple Shoulder Test, and Subjective Shoulder Value scores were analyzed preoperatively and at final follow-up. Radiographic evidence of union, maintenance of reduction and complications were recorded. All patients were available for 1-year follow-up.

RESULTS

Mean Visual Analog Scale pain score improved from 6.1±1.1 to 1.1±1.0 (P=0.022). American Shoulder and Elbow Surgeons scores increased from 40.3±17.2 to 86.7±13.7 (P≤0.001). The mean Simple Shoulder Test score increased from 2.7±1.1 to 11.0±1.8 (P≤0.001). The Subjective Shoulder Value improved from 41.6±19.1 to 91.4±7.6 (P=0.210). Fracture united in 6 of 7 patients and reduction was maintained in all patients. Six patients were satisfied and returned to previous activity level.

CONCLUSIONS

Arthroscopy-assisted fixation of unstable displaced distal clavicle fractures demonstrates improved functional outcomes and high patient satisfaction. This construct avoids many of the previously reported complications associated with other methods of fixation, while minimizing the amount of soft tissue dissection.

Biomechanical Comparison of Screw Fixation Versus a Cortical Button and Self-tensioning Suture for the Latarjet Procedure

Background

Metal screws are traditionally used to fix the coracoid process to the glenoid. Despite stable fixation, metal screws have been associated with hardware complications. Therefore, some studies have advocated for suture button fixation during the Latarjet procedure to reduce the complications associated with screw fixation.

Purpose

To biomechanically evaluate the ultimate failure load of a cortical button and self-tensioning suture versus metal screws for coracoid graft fixation during the Latarjet procedure.

Study Design

Controlled laboratory study.

Methods

Eight matched pairs of fresh-frozen, male cadaveric shoulders (N = 16) underwent the Latarjet procedure. The shoulders of each pair were randomly assigned to 1 of 2 groups: fixation using two 3.75-mm cannulated, fully threaded metal screws or fixation using a double suture button construct. Specimens were secured in a dynamic testing machine and cyclically preconditioned from 2 to 10 N at 0.1 Hz for 10 cycles. After preconditioning, specimens were pulled to failure at a normalized displacement rate of 400% of the measured gauge length per minute. The ultimate failure load and mechanism of failure were recorded for each specimen.

Results

The mean ultimate load to failure for screw fixation (226 ± 114 N; 95% CI, 147-305 N) was not significantly different from that for suture button fixation (266 ± 73 N; 95% CI, 216-317 N) (P = .257). The mean strain at failure for screw fixation (63% ± 21%; 95% CI, 48%-77%) was not significantly different from that for suture button fixation (86% ± 26%; 95% CI, 69%-104%) (P = .060). The most common mechanism of failure for the screw fixation method was at the bone block drill holes, while an intramuscular rupture at the clamp-muscle interface occurred for the suture button construct.

Conclusion

The screw and suture button fixation techniques exhibited comparable biomechanical strength for coracoid bone block fixation of the Latarjet procedure.

Clinical Relevance

Metal screws have been reported to be a large contributor to intraoperative and postoperative complications. Therefore, given the results of the current study, a suture button construct may be an alternative to metal screw fixation during the Latarjet procedure. However, further clinical studies are warranted.

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.

Distal Clavicle Fracture Repair Using Cortical Button Fixation With Coracoclavicular Ligament Reconstruction

Management of distal clavicle fractures remains controversial. Various treatment options have been described including open reduction and internal fixation with hook plate fixation, tension band wiring, screw fixation, and distal locking plates. Many of these techniques are associated with a high perioperative complication rate. We describe a surgical technique that allows indirect fixation of distal clavicle fractures and reconstruction of the CC ligaments without the use of prominent hardware.

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.

Arthroscopic-Assisted Coracoclavicular Ligament Reconstruction for Acute Acromioclavicular Dislocation Using 2 Clavicular and 1 Coracoid Cortical Fixation Buttons With Suture Tapes

PURPOSE

To introduce an arthroscopically assisted coracoclavicular (CC) fixation technique using a cortical fixation button device and to evaluate the clinical and radiologic outcomes in patients with acute acromioclavicular (AC) dislocation who were treated with the technique.

METHODS

Twenty-one consecutive patients with grade III and V acute AC dislocation who underwent arthroscopically assisted CC ligament reconstruction using a cortical fixation button device were prospectively enrolled. Our fixation technique involved using a cortical fixation button device consisting of 1 coracoid button and 2 clavicular buttons connected with 2 suture tapes to reconstruct the conoid and trapezoid ligaments, respectively. Clinical outcomes were evaluated and CC distance and horizontal displacement of the AC joint were measured.

RESULTS

The mean follow-up period was 27.2 months (range, 24-32 months). The average CC distance of the injured shoulder was 17.2 ± 5.2 mm preoperatively, which represented an increase of 103% ± 42% compared with the uninjured shoulder. The CC distance was significantly reduced to 8.5 ± 1.5 mm after surgery (P < .001). At the final follow-up, the CC distance was maintained in 20 patients (95%) without loss of reduction. No significant radiologic difference was found in horizontal displacement of the AC joint immediately after the operation and at the final follow-up (P = .422). The average American Shoulder and Elbow Surgeons and Constant scores were 95.7 ± 3.6 and 95.4 ± 3.4, respectively. There were 3 complications, including 1 reduction loss, 1 coracoid process fracture, and 1 CC interval ossification.

CONCLUSIONS

Satisfactory clinical and radiologic outcomes were obtained simultaneously by arthroscopically assisted CC reconstruction using cortical fixation buttons. This reconstruction technique provided sufficient stability of the AC joint by using 2 clavicular holes to reconstruct the conoid and trapezoid ligaments separately. Therefore, arthroscopically assisted CC ligament reconstruction using a cortical fixation button device for management of acute AC dislocation is considered a viable treatment option for restoring stability to the AC joint.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Lateral clavicle fracture with coracoclavicular ligament injury: a biomechanical study of 4 different repair techniques

PURPOSE

To investigate the biomechanical performance of four different methods used for coracoclavicular (CC) ligament reconstruction in a lateral clavicle fracture repair.

METHODS

Native displacement, translation, and rotation at the acromioclavicular joint of 24 fresh-frozen cadaveric shoulders were tested. A reproducible fracture in the lateral third of the clavicle was created by dissecting both CC ligaments. Each specimen was then repaired with plate fixation of the fracture and the following CC repair technique: (1) Cortical button. (2) Suture anchor and plate button. (3) Suture anchor no plate button, and (4) Suture around coracoid. All reconstructed specimens were then re-tested for displacement, translation, and load to failure, and compared to their native results. Groups 1 and 3 were investigated for rotational load.

RESULTS

There was no difference in load to failure between the repaired groups (p: ns). Group 1 showed less superior and anterior translations (p < 0.05). Group 2 showed significantly less superior translation (p = 0.003), but no significance with anterior and posterior translations to the native joint. Group 3 showed less superior and posterior translations (p = 0.005 and p = 0.039). Anterior and posterior translations were increased in group 4 (p < 0.05).

CONCLUSION

The biomechanical analyses did not show any significance in load to failure or displacement after cyclic loading among the study groups. All repairs were effective in preventing superior translation. Groups 1 and 2 demonstrated increased horizontal stability compared to the native state. All 4 methods are clinically viable options for CC ligament repair.

Arthroscopic Acromioclavicular Joint Reconstruction Using Knotless Coracoclavicular Fixation and Soft-Tissue Anatomic Coracoclavicular Ligament Reconstruction

Acromioclavicular joint injuries are one of the most common shoulder injuries, and there are a variety of treatment options. Recently, there have been newer arthroscopic techniques that have addressed coracoid and clavicle fracture risk by using a knotted suture-button fixation through a single, small bone tunnel with additional looped soft-tissue graft stabilization. Although clinical outcomes have been good to excellent, there have still been instances of knot and hardware irritation. The described technique builds on the latest advances and achieves an anatomic coracoclavicular (CC) reconstruction through a single knotless CC fixation device with additional soft-tissue allograft reconstruction of the CC ligaments. This technique minimizes the risks of coracoid and clavicle fractures and knot and hardware irritation while maintaining excellent stability.

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

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

Editorial Commentary: The Larger Holes or Larger Number of Holes We Drill in the Coracoid, the Weaker the Coracoid Becomes

The larger holes or larger number of holes we drill in the coracoid, the weaker the coracoid becomes. Thus, minimizing bone holes (both size and number) is required to lower risk of coracoid process fracture, in patients in whom transosseous shoulder acromioclavicular joint reconstruction is indicated. A single 2.4-mm-diameter tunnel drilled through both the clavicle and the coracoid lowers the risk of fracture, but the risk cannot be entirely eliminated.