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

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.

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.

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.

[Injuries of the shoulder in winter sports]

Skiing as a sport has come a long way from the first competitive event in Norway in 1767 to about 200 million skiers today worldwide. With Germany alone recording around 8000 injuries annually, there is an increased need for awareness for winter-sport-related injuries and their management. According to the latest report by "Auswertungsstelle für Skiunfälle" (ASU, evaluation center for ski accidents), shoulder injuries alone account for more than 20% of injuries to all body regions (men 26.1% and women 13%). The most common injuries affecting the shoulder girdle are rotator cuff strains, glenohumeral dislocations, acromioclavicular dislocations and clavicle fractures. These injuries are primarily the result of four mechanisms: direct impact, axial load on an extended arm, resisted forced abduction of the arm, and external rotation forces resulting from a firmly planted ski pole in the grasp of a skier during a fall. In this article, we describe the three most common shoulder girdle injuries in winter sports along with their management and answer the most important questions for the athlete.

Clinical and anatomical outcomes of isolated coracoclavicular fixation after acromioclavicular joint injury: is it stable enough or is additional horizontal fixation necessary?

Background

Recently, an emphasis has been put on anatomical reduction of acromioclavicular (AC) joint both in vertical and hortizontal planes for management of AC joint injuries due to persisting horizontal instability. Therefore, an additional AC fixation in horizontal plane has been recommended. However, relation between horizontal AC joint instability and clinical outcomes is still controversial. This study aims to evaluate outcomes of isolated coraco-clavicular fixation using arthroscopic assisted single coraco-clavicular tunnel technique in grade III and V AC joint injuries and to investigate the correlation between anatomical and clinical outcomes.

Methods

This study was conducted with 19 patients with grade III or V AC joint injury. Clinical outcomes included postoperative pain intensity and functional outcomes (Constant Score, American Shoulder and Elbow Surgeons, and Subjective Shoulder Value). Radiological evaluations were performed using radiographs and postoperative computed tomography scans. Degree of initial injury and postoperative stability both on axial and coronal planes were evaluated after radiological assessment. Correlations between anatomical and clinical outcomes were investigated using Pearson's correlation test.

Results

At the final follow-up assessment, the mean pain score was 1.8 ± 1.8, mean American Shoulder and Elbow Surgeons score was 81.0 ± 15.4, mean Subjective Shoulder Value was 81.3 ± 19.6, and mean Constant Score was 86.3 ± 14.8. The mean loosening ratio and AC distance were 43.5 ± 30.6% and 4.3 ± 12.4 mm, respectively. No correlation was observed between postoperative anatomical and clinical outcomes (P > .05).

Conclusion

Additional AC fixation on horizontal plane is not a prerequisite for all injuries, there is no significant association between horizontal instability and clinical outcomes and indications of an additional AC fixation needs to be determined.

Horizontal instability after acromioclavicular joint reduction using the two-hole technique is preferred over the loop technique: a single-blind randomized clinical trial

Background

Most acromioclavicular joint (ACJ) injuries are caused by direct trauma to the shoulders, and various methods and techniques are used to treat them; however, none of the options can be considered the gold standard. This study examines the horizontal stability of the ACJ after a complete dislocation was repaired using one of two Ethibond suture techniques, the loop technique and the two holes in the clavicle technique.

Methods

In this single-blind, randomized clinical trial, 104 patients diagnosed with complete ACJ dislocation type V were treated using Ethibond sutures with either the loop technique or the two holes in the clavicle technique. Horizontal changes in the ACJ were radiographically assessed in the lateral axial view, and shoulder function was evaluated by the Constant (CS) and Taft (TS) scores at intervals of 3, 6, and 12 months after surgery.

Results

The horizontal stability of the ACJ was better with the two-hole technique than the loop technique at all measurement times. CS and TS changes showed a significant upward trend over time with both techniques. The mean CS and TS at the final visit were 95.2 and 11.6 with the loop technique and 94.0 and 11.9 with the two-hole technique, respectively. The incidence of superficial infections caused by the subcutaneous pins was the same in the two groups.

Conclusions

Due to the improved ACJ stability with the two-hole technique, it appears to be a more suitable option than the loop technique for AC joint reduction.

Combination of Surgical Techniques Restores Multidirectional Biomechanical Stability of Acromioclavicular Joint

PURPOSE

To measure the multiaxial stability of the acromioclavicular joint before and after transection of the acromioclavicular capsule and coracoclavicular ligaments and after sequential repair of acromioclavicular and coracoclavicular ligaments.

METHODS

Biomechanical testing was performed on fresh-frozen human cadaveric shoulders (N = 6). Translational and rotational stability in the vertical and horizontal planes was measured in intact specimens, after transecting the acromioclavicular and coracoclavicular ligaments, and after sequentially performing the following procedures: single-bundle coracoclavicular repair (CCR), modified Weaver-Dunn procedure (WD), and acromioclavicular stabilization (ACS).

RESULTS

Resecting the acromioclavicular and coracoclavicular significantly reduced translational stiffness in the inferior and anteroposterior directions, as well as rotational stiffness about the vertical and anteroposterior axes. All 3 surgical procedures increased inferior translational stiffness relative to the intact condition (Intact: 38 ± 9 N/mm, CCR: 54 ± 23 N/mm (P = .03), CCR+WD 52 ± 20 N/mm (P = .07), CCR ± WD+ACS 50 ± 21 N/mm (P = .17)). However, the combination of CCR, modified WD, and ACS resulted in the greatest increase in stiffness in internal rotation (Intact: 12.5 ± 7.4 cNm/deg, CCR: 1.2 ± 1.1 cNm/deg, CCR+WD 7.2 ± 3.0 N∗m/deg [P = .023], CCR+WD+ACS 11.6 ± 4.9 cNm/deg [P = .055]).

CONCLUSIONS

The cumulative stability of CCR, WD reconstruction, and ACS appears to be additive. Our findings provide a biomechanical justification for combining all three techniques. Biomechanical studies assessing the performance of various acromioclavicular repairs and reconstructions should therefore incorporate multiaxial testing in their protocols.

CLINICAL RELEVANCE

Multiple points of fixation that provide multidirectional stability have the potential to improve clinical outcomes and reduce failure rates of acromioclavicular joint repair or stabilization.

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.

Restoring Horizontal Stability of the Acromioclavicular Joint: Open Acromioclavicular Ligament Reconstruction and Repair With Semitendinosus Allograft

Injuries to the acromioclavicular (AC) joint are common and comprise ∼12% of shoulder injuries. Stability to the AC joint depends on the coracoclavicular (CC) ligaments for vertical stability and AC ligaments and capsular structures for horizontal stability. Injuries to the AC ligaments can lead to horizontal instability of the AC joint. There is no gold standard technique for treating these injuries surgically, and many of the described procedures focus on vertical instability rather than horizontal instability. This article describes an open AC ligament reconstruction with semitendinosus allograft to restore horizontal stability of the AC joint.

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.

Horizontal Instability of the Acromioclavicular Joint: A Systematic Review

BACKGROUND

Injuries to the acromioclavicular (AC) joint are common and should be suspected in patients who have shoulder pain in the region of the acromion and clavicle. Injuries to the AC ligament can cause horizontal instability and are often neglected or underdiagnosed, which can lead to poor patient outcomes.

PURPOSE

To perform a systematic review of the literature on the diagnosis and treatment of horizontal instability of the AC joint.

STUDY DESIGN

Systematic review.

METHODS

The authors performed a systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and EMBASE were searched for studies that investigated diagnosis, treatment, and failure of operative management of acute and chronic AC separations. Studies that did not specifically evaluate AC joint injuries, were not written in English, or were specific only to vertical instability of the AC joint were excluded.

RESULTS

Overall, 23 articles met the inclusion criteria and were therefore included in this systematic review. Diagnosing horizontal AC instability is difficult using plain radiographs; dynamic views were shown in some cases to better detect horizontal instability than with static views. More than 60 procedures for treating AC joint injuries have been published, but many focus on vertical rather than horizontal instability. Modifications to current surgical procedures to incorporate reconstruction of the horizontal component showed improved patient outcomes. Such modifications included additional AC joint suture cord cerclage, combined AC and coracoclavicular ligament reconstruction, and the Twin Tail TightRope triple button technique. Failure after surgical stabilization of AC joint separation has been reported to occur in 15% to 80% of cases.

CONCLUSION

No consensus is available regarding the best practices for diagnosis, evaluation, and treatment of acute or chronic horizontal instability of the AC joint. Moreover, horizontal instability injuries are often neglected or poorly understood, making diagnosis difficult, which may lead to high complication rates and failure after surgical stabilization.

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

Reconstruction of the Acromioclavicular Ligament Complex Using Dermal Allograft: A Biomechanical Analysis

PURPOSE

To analyze the posterior translational and rotational stability of the acromioclavicular (AC) joint following reconstruction of the superior acromioclavicular ligament complex (ACLC) using dermal allograft.

METHODS

Six fresh-frozen cadaveric shoulders were used (mean age of 65.3 ± 6.9 years). The resistance force against posterior translation (10 mm) and torque against posterior rotation (20°) was measured. Specimens were first tested with both the intact ACLC and coracoclavicular ligaments. The ACLC and coracoclavicular ligaments were then transected so simulate a Type III/V AC joint dislocation. Each specimen then underwent 3 testing conditions, performed in the following order: (1) ACLC patch reconstruction alone, (2) ACLC patch with an anatomic coracoclavicular reconstruction (ACCR) using semitendinosus allograft, and (3) the transected ACLC with an ACCR only. Differences in posterior translational and rotational torque across testing conditions were analyzed with a one-way repeated analysis of variance analysis.

RESULTS

Mean resistance against posterior translation in the intact condition was 65.76 ± 23.8 N. No significant difference found between the intact condition compared with specimens with the ACLC-patch only (44.2 ± 11.3 N, P = .06). The ACCR technique, when tested alone, had significantly less posterior translational resistance compared with the intact condition (38.5 ± 8.94 N, P = .008). ACLC patch in combination with an ACCR was closest in restoring native posterior translation (57.1 ± 19.2 N, P = .75). For rotational resistance, only the addition of the ACLC patch with an ACCR (0.51 ± 0.07 N-m) demonstrated similar torque compared with the intact joint (0.89 ± 0.5 N-m, P = .06).

CONCLUSIONS

The ACLC-patch plus ACCR technique was able to closest restore the percent of normal posterior translational and rotational stability.

CLINICAL RELEVANCE

Recurrent posterior instability of the AC joint is a potential complication after coracoclavicular reconstruction surgery. In the in vitro setting, this study demonstrated increased AC joint stability with the addition of an ACLC reconstruction using dermal allograft.

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.

Arthroscopic Coracoacromial Ligament Transfer Augmented With Suspensory V-Shaped Fixation System for Chronic Acromioclavicular Joint Dislocation

Chronic acromioclavicular joint dislocations (ACJDs) develop when there is failure of conservative treatment, failed surgical treatment of acute ACJD, or simply missing the treatment in the acute healing phase. There is wide agreement that mechanical fixation alone in chronic ACJD is not sufficient and biological augmentation is necessary. Various arthroscopic techniques for reconstruction of the coracoclavicular ligament have been described, but allografts are expensive, are not available in all centers, carry the risk of disease transmission, and are "dead tissue" with a poor capacity for healing. Autografts are associated with donor-site morbidity and avascular structures. Moreover, these grafts are associated with a high risk of clavicular or coracoid fractures owing to large tunnels. We present an arthroscopic technique to transfer the coracoacromial ligament to the inferior surface of the lateral part of the clavicle in chronic ACJD, augmented with 2 clavicular buttons and a single coracoid button in a V-shaped configuration. The technique has various advantages including better stabilization, anatomic reconstruction, and a minimal risk of fracture of the coracoid and clavicle with small tunnels, using a vascularized graft with arthroscopic control of reduction.

All-Arthroscopic Reconstruction of Severe Chronic Acromioclavicular Joint Dislocations

PURPOSE

To report the outcomes of all-arthroscopic coracoclavicular (CC) ligament reconstruction and simultaneous diagnosis and treatment of glenohumeral pathologies in patients with symptomatic, chronic (>6 weeks), complete (Rockwood type III-V) acromioclavicular joint (ACJ) separations.

METHODS

We prospectively followed up 57 consecutive patients treated arthroscopically for chronic Rockwood type III (n = 11), type IV (n = 19), and type V (n = 27) ACJ dislocations. Previous ACJ surgery failed in 11 (19%). The mean delay between injury and surgery was 39 months (range, 6 months to 17 years). The mean age at surgery was 42 years (range, 19-71 years). After glenohumeral exploration, an arthroscopic modified Weaver-Dunn procedure with CC suture button fixation (Twinbridge) was performed. The CC reduction and tunnel position were analyzed with radiographs and computed tomography. The mean follow-up period was 36 months (range, 12-72 months).

RESULTS

Intra-articular pathology was treated arthroscopically in 27 patients (48%): 17 labral tears, 8 rotator cuff tears (3 partial and 5 complete), and 15 biceps lesions (4 SLAP lesions and 11 subluxations). At last follow-up, 7 patients (12%) experienced recurrent ACJ instability: 2 frank dislocations (1 trauma and 1 infection) and 5 ACJ subluxations. There was no significant correlation between subluxation and clinical outcome. The rate of recurrent ACJ instability was significantly higher in patients with higher-grade ACJ dislocations (P < .01) and/or previous failed surgery (P < .001). Recurrent subluxation was observed in 3 cases of lateral migration of the coracoid button with lateral tunnel placement, as well as 2 cases of anterior migration of the clavicular button with anterior tunnel placement. The Constant score increased from 67 (range, 28-89) to 85.5 (range, 66-100), and the mean Subjective Shoulder Value increased from 54% to 85% (P < .001). At last follow-up, 95% of patients (54 of 57) were satisfied.

CONCLUSIONS

All-arthroscopic treatment allows successful CC ligament reconstruction and simultaneous diagnosis and treatment of frequently associated (48%) glenohumeral lesions. Higher-grade ACJ dislocations, previous ACJ surgery, and misplacement of bone tunnels are risk factors for recurrent instability.

LEVEL OF EVIDENCE

Level IV, case series.

The Integrity of the Acromioclavicular Capsule Ensures Physiological Centering of the Acromioclavicular Joint Under Rotational Loading

BACKGROUND

The acromioclavicular (AC) capsule is an important stabilizer against horizontal translation and also contributes to the strut function of the clavicle, which guides rotation of the scapula. To best reproduce the biomechanical properties and the complex 3-dimensional (3D) guidance of the AC joint, detailed knowledge of the contribution of each of the distinctive capsular structures is needed. Purpose/Hypothesis: To perform a detailed biomechanical evaluation of the specific capsular structures of the AC joint and their contribution to translational and rotational stability. The hypothesis was that successive cutting of each quadrant of the AC capsule would result in increased instability and increased amplitude of the clavicle's motion in relation to the acromion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-two fresh-frozen human cadaveric shoulders were used. Each scapula was fixed to a swivel fixture of a servohydraulic materials testing system. The AC capsule was dissected in serial steps with immediate rotational and horizontal testing after each cut. A 3D optical measuring system was used to evaluate 3D movement. Posterior translation, rotation, and displacement of the lateral clavicle in relation to the center of rotation were measured. Torques and axial forces required to rotate and translate the clavicle were recorded.

RESULTS

When posterior translational force was applied, all specimens with a completely cut AC capsule demonstrated a significant loss of resistance force against the translational motion when compared with the native state ( P < .05). The resistance force against posterior translation was reduced to less than 27% of the native state for all specimens. Sequential cutting of the AC capsule resulted in a significant reduction of resistance torque against anterior rotation for all specimens with less than 22% of resistance force compared with the native state. Cutting 50% of the capsule reduced the resistance torque for all segments and all testing modalities (posterior translation as well as anterior and posterior rotation) significantly compared with the native state ( P < .05). Cutting the entire AC capsule resulted in a significant increase in motion within the joint as a sign of decentering of the AC joint when torque was applied. All groups demonstrated a significant increase of motion in all directions when the AC capsule was cut by 50%.

CONCLUSION

Cutting the entire capsule (with intact coracoclavicular [CC] ligaments) reduced the resistance force to less than 25% compared with the native state during translational testing and less than 10% compared with the native state during rotational testing. However, the anterior segments of the capsule provided the greatest stability under rotational loading. Second, the amplitude of the joint's motion significantly increased under rotational stress, indicating increased amplitude of the clavicle's motion in relation to the acromion when the ligamentous structures of the AC capsule are dissected.

CLINICAL RELEVANCE

To best restore stability to the AC joint, the relevance and function of each section of the circumferential AC capsule need to be understood. Our findings support the synergistic contribution of the CC ligaments and AC capsular structures to AC joint stability. This synergy supports the need to address both structures to achieve anatomic reconstruction.

Arthroscopic Coracoclavicular Ligament Reconstruction Using Graft Augmentation and Titanium Implants

Several techniques have been introduced to treat acromioclavicular separation with coracoclavicular ligament reconstruction using graft augmentation. A modified arthroscopic technique for coracoclavicular ligament reconstruction was used based on a previous technique where the supportive device and tendon graft share the clavicular and coracoid drill holes. A notable problem with the previous technique was large protruding suture knots on the washer and clavicle, which could predispose to wound infection. In this modified technique, titanium implants were introduced. The implants hid the suture knot on the clavicle, and less foreign material was needed between the clavicular and coracoid implants.

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.