Intramedullary acromioclavicular ligament reconstruction strengthens isolated coracoclavicular ligament reconstruction in acromioclavicular dislocations

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.

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.

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

BACKGROUND

Although the coracoclavicular (CC) ligaments are classically reconstructed after acromioclavicular (AC) joint injuries, biomechanical studies over the past decade have indicated the importance of an additional reconstruction of the AC ligaments. To date, no kinematic study has investigated the kinematic differences between these reconstruction strategies.

PURPOSE

To evaluate the restoration of shoulder motion after an AC injury using a CC ligament, an AC ligament, or a combined reconstruction technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

After creating a Rockwood grade V lesion in 14 cadaveric shoulders, the AC joint injury was treated with either a CC ligament reconstruction using a suspension device, an in situ AC ligament reconstruction using 2 coupled soft tissue anchors, or a combination of these 2 techniques. Joint motions were registered during humerothoracic elevation in the coronal plane and protraction in the intact shoulder in a Rockwood V lesion and after the 3 reconstruction strategies. An optical navigation system measured 3-dimensional rotation in the sternoclavicular and scapulothoracic joints, and both rotation and translation were analyzed in the AC joint.

RESULTS

In the sternoclavicular joint, the CC and combined reconstruction techniques adequately restored clavicular axial rotation, while the AC reconstruction technique showed a better correction of clavicular elevation. Scapulothoracic joint rotations were best restored by reconstructing the AC ligaments. In the AC joint, the relative tilting position and the lateral rotation of the scapula compared with the clavicle were best restored by the suspension device and combined reconstruction. The AC ligament reconstruction technique demonstrated a better restoration of the relative protracted position and resulted in a better correction of the translation of the scapula relative to the clavicle.

CONCLUSION

This study illustrates that there are kinematic differences between AC, CC, or combined ligament reconstruction strategies. Although each technique was able to restore different elements of the joint kinematics, none of the strategies completely restored the shoulder girdle to its preinjured state.

CLINICAL RELEVANCE

Humerothoracic movements after Rockwood V lesions are best restored using the CC reconstruction technique, and scapulothoracic movements are best restored using the AC ligament reconstruction technique.

The Morphology of the Acromioclavicular Joint Does Not Influence the Postoperative Outcome Following Acute Stabilization—A Case Series of 81 Patients

Purpose

To specifically evaluate the influence of the acromioclavicular (AC)-joint morphology on the outcome after arthroscopically assisted coracoclavicular (CC) stabilization surgery with suspensory fixation systems and to investigate whether an additional open AC-joint reduction and AC cerclage improves the clinical outcome for patients with certain morphologic AC-joint subtypes.

Methods

Patients with an acute acromioclavicular joint injury, who underwent arthroscopically assisted CC stabilization with suspensory fixation systems with or without concomitant AC cerclage between January 2009 and June 2017 were identified and included in this retrospective cohort analysis. AC-joint morphology was assessed on preoperative radiographs and categorized as “flat” or “non-flat” (“oblique”/“curved”) subtypes. After a minimum of 2 years of follow-up, postoperative Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES), and visual analog scale (VAS) scores for pain were collected. A subgroup analysis of clinical outcomes depending on the surgical technique and morphological subtype of the AC joint was performed.

Results

Eighty-one patients (95% male, mean age 35 ± 12 years) could be included at a mean follow-up of 57 ± 14 months. Radiographic assessment of AC-joint morphology showed 24 (30%) cases of flat type, 38 (47%) cases of curved type, and 19 (23%) cases of oblique morphology. Postoperatively, no clinically significant difference could be detected after the treatment of AC joint injury via CC stabilization with or without concomitant AC cerclage (VAS_rest: P = .067; VAS_max: P = .144, ASES: P = .548; SANE: P = .045). No clinically significant differences were found between the surgical techniques for the flat morphologic subtype (VAS_rest: P = .820; VAS_max: P = .251; SANE: P = .104; ASES: P = .343) or the non-flat subtype (VAS_res: P = .021; VAS_max: P = .488; SANE: P = .243, ASES: P = .843).

Conclusions

In arthroscopically assisted AC stabilization surgery with suspensory fixation systems for acute AC-joint injury, the AC-joint morphology did not influence the postoperative outcome, independent of the surgical technique. No clinical benefit of performing an additional horizontal stabilization could be detected in our collective at mid-term follow-up.

Level of Evidence

Level IV, therapeutic case series.

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.

Acromioclavicular joint augmentation at the time of coracoclavicular ligament reconstruction fails to improve functional outcomes despite significantly improved horizontal stability

PURPOSE

Acromioclavicular joint reconstruction is a well-established and frequently performed procedure. Recent scientific and commercial interest has led to a drive to develop and perform surgical techniques that more reliably restore horizontal stability in order to improve patient outcomes. The aim of this systematic review was to evaluate the biomechanical evidence for procedures directed at restoring horizontal stability and determine whether they are associated with superior clinical results when compared to well-established procedures.

METHODS

A review of the online databases Medline and EMBASE was conducted in accordance with the PRISMA guidelines on the 23rd December 2017. Biomechanical and clinical studies reporting either static or dynamic horizontal displacement following acromioclavicular joint reconstruction (Coracoclavicular reconstruction or Weaver-Dunn) were included. In addition, biomechanical and clinical studies reporting outcomes after additional augmentation of the acromioclavicular joint were included. The studies were appraised using the Methodological index for non-randomised studies tool.

RESULTS

The search strategy identified 18 studies eligible for inclusion: six biomechanical and 12 clinical studies. Comparative biomechanical studies demonstrated that acromioclavicular augmentation provided significantly increased horizontal stability compared to the coracoclavicular reconstruction and Weaver-Dunn procedure. Comparative clinical studies demonstrated no significant differences between coracoclavicular reconstruction with and without acromioclavicular augmentation in terms of functional outcomes (American Shoulder and Elbow Surgeon and Constant score), complication or revision rates. However, one comparative study did demonstrate an improvement in Taft (p = 0.018) and Acromioclavicular Joint Instability scores (p = 0.0001) after acromioclavicular augmentation.

CONCLUSION

In conclusion, coracoclavicular reconstruction with augmentation of the acromioclavicular joint has been shown to provide improved horizontal stability in both biomechanical and clinical studies compared to isolated coracoclavicular reconstruction. However, comparative studies have shown no clinical advantage with respect to American Shoulder and Elbow Surgeon or Constant scores and, therefore, the results of this systematic review do not support acromioclavicular augmentation in routine clinical practice.

LEVEL OF EVIDENCE

IV.

Biomechanical comparison of two biplanar and one monoplanar reconstruction techniques of the acromioclavicular joint

INTRODUCTION

The purpose of this proof-of-concept study was to investigate the biomechanical performance of two surgical techniques, namely (1) the double Tight-Rope fixation with an additional acromioclavicular FiberTape fixation (DTRC) and (2) the fixation of the clavicle to the acromion and coracoid in a bipodal manner (Bipod) using a Poly-Tape and FiberTape. Both techniques intend to address vertical and horizontal instability after acromioclavicular dislocation. They were compared with the commonly used (3) double Tight-Rope (DTR) technique, which only stabilizes the clavicle to the coracoid.

MATERIALS AND METHODS

The acromioclavicular joint (ACJ) of 18 composite Sawbone shoulder specimens (6 per reconstruction group) were tested for posterosuperior elongation (70N cyclical load, 1500 cycles), load-to-failure and stiffness.

RESULTS

After 1500 cycles, the DTRC, Bipod and DTR group showed an elongation of 0.45 mm (SD 0.14 mm), 1.19 mm (SD 0.54 mm), and 0.46 mm (SD 0.15 mm), respectively. Although the elongation of the Bipod group was increased when compared to the other two groups (Bipod versus DTRC p = 0.008; Bipod versus DTR p = 0.006), the difference was less than 0.7 mm. The DTRC showed a higher load-to-failure of 656.1N (SD 58.1 N) compared to the Bipod [531.1 N (SD 108.2N) (p = 0.039)] and DTR group [522.8 N (SD 32.8 N) (p = 0.033)].

CONCLUSION

The DTRC and the DTR group resulted in similar low elongation, while the elongation in the Bipod technique was slightly higher. Even though this difference of 0.7 mm shows statistical significance, it most likely has no clinical relevance. When testing in posterosuperior direction, which is the clinically relevant load vector, an additional fixation of the clavicle to the acromion did not reduce elongation in this study. It is, furthermore, questionable if the benefit of an increased load-to-failure in combination with no improvement in elongation and stiffness as seen in the DTRC group outweighs the possible risks and increased costs coming with the DTRC refixation.

Percutaneous endobutton fixation of acute acromioclavicular joint injuries and lateral clavicle fractures

INTRODUCTION

This paper describes a novel technique developed by the senior author to address acute acromioclavicular joint (ACJ) dislocations and certain distal clavicle fractures.

METHODS

The procedure employs a four strand, single tunnel, double endobutton repair performed entirely percutaneously, without any arthroscopic guidance or deep surgical dissection.

RESULTS

We present the preliminary results from our series of 6 consecutive patients performed over a period of 18 months. The mean length of surgery was 36min (range 32-40) and the mean correction of coracoclavicular (CC) distance achieved was 12.6 mm (range 10.3-14.1). There was no restriction of movement in any of the patients post-operatively and their average QuickDASH scores at final follow-up was 4.2 (range 0-6.8).

CONCLUSION

Results in the present series were at least comparable to those for other techniques, validating percutaneous treatment as a solution for acute ACJ dislocations.

Primary Stability of an Acromioclavicular Joint Repair Is Affected by the Type of Additional Reconstruction of the Acromioclavicular Capsule

BACKGROUND

The synergistic effect of the acromioclavicular (AC) capsule and coracoclavicular (CC) ligaments on AC joint stability has gained recent recognition for its importance. Biomechanical and clinical studies have shown the benefit of combined reconstruction with multiple variations of surgical techniques for AC capsule augmentation. The ideal configuration remains unknown for such capsular repair aimed at achieving optimal stability with anatomic reconstruction.

HYPOTHESIS

Primary AC joint stability can be restored by AC capsule augmentation, while position of the additional suture construct is critical. It was hypothesized that techniques that reconstruct the anterior capsular structures would restore native stability against rotations and translations.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty fresh-frozen human cadaveric shoulders were used. Each sample was tested in the native state and served as its own control. After complete capsulotomy, 1 of 5 AC capsular repair configurations was performed: anterior, superior, posterior, O-frame, and X-frame. After testing of the AC capsular repair configurations, the tests were repeated after dissection of the CC ligaments and after CC ligament reconstruction with a suture button system. AC joint stability was immediately tested after each step under rotation and horizontal translation. To accomplish this, the AC joints were anatomically positioned on a custom fixture linked to a servohydraulic testing system. A 3-dimensional optical measuring system was used to evaluate the 3-dimensional joint motion. Clavicle posterior translation in relation to the acromion, rotation around the long axis of the clavicle, and displacement of the lateral clavicle in relation to the center of rotation were measured. The torques and forces required to rotate and translate the clavicle were recorded.

RESULTS

In terms of translational testing, after the complete capsulotomy, a significant reduction of resistance force was found across all groups, with a mean 13% to 20% remaining ( P < .05). All AC suture augmentations were able to significantly increase the average resistance force as compared with the native ( P = .01) against posterior translation. Subsequent cutting of the CC ligaments did not result in a significant change in any of the groups ( P = .23). The synergistic effect of AC capsule augmentation and CC ligament reconstruction could be demonstrated without exception. In terms of rotational testing, the complete capsulotomy resulted in a significant reduction of resistance torque in all groups ( P < .05), with a remaining torque ranging between 2% and 11% across the groups. However, all AC suture constructs significantly increased the resistance torque as compared with the capsulotomy ( P = .01). The subsequent cutting of the CC ligaments resulted in a significant change in 2 of the 5 groups (O-frame, P = .01; X-frame, P = .02) and an overall remaining torque reduction ranging from 3% and 42%. The combined reconstruction of the AC capsule and CC ligaments achieved the highest percentage of regained resistance torque but remained significantly weaker than the native specimen ( P = .01).

CONCLUSION

Native translational stability could be restored by the addition of AC capsule augmentation, while partial rotational instability remained. The tested constructs revealed no significant individual differences.

CLINICAL RELEVANCE

Combined stabilization of the AC capsule and CC ligaments demonstrated the greatest capacity to restore the native stability against translational and rotational loads, with the specific configuration of the AC capsule repair to be chosen according to the personal preferences of the surgeon.

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.

Acromion morphology and bone mineral density distribution suggest favorable fixation points for anatomic acromioclavicular reconstruction

PURPOSE

Recent techniques for acromioclavicular (AC) joint reconstruction focus on additional AC cerclage to coracoclavicular (CC)-reconstructions. Due to the specific slim bone morphology at the acromion, there are concerns regarding these additional bone tunnels, as they may predispose to fracture and break out. The purpose of this study was to investigate anatomic properties of the acromion which may help improve surgical techniques directed at injuries to the AC joint. It was hypothesized that via measurements of thickness and density points of increased strength and support could be identified on the acromion.

METHODS

Eighty-five fresh frozen cadaveric shoulders were used for this study. A standardized 3D-net was developed and thicknesses of the acromion were taken from defined points using a certified caliper. To define the acromial arch, the angle and radius of curvature between the antero-lateral, the highest point of the acromial arch and the postero-lateral aspect of the acromion were measured. Additional bone mineral density (BMD) evaluation was performed on 43 specimens in an anterio-posterior and latero-medial direction using 5-mm slices with a maximum of 10 and 6 slices, respectively.

RESULTS

Median specimen age was 63.0 (range 36) years (55 female, and 30 male). There was no statistical significance between male (62.0, range: 35 years) and female (64.5, range 32 years) regarding age (n.s.). Thickness of acromion points of interest were ranging from 3.5 to 24.3 mm. Median radius of curvature of acromial arch for female was 48.2 (range 92.7) mm and 66.2 (range 85.6) for male (p = 0.019). The median angle for female specimens was 21.4° (range: 44.6°) and 23.3° (range 51.7°) for male (p = 0.047). The latero-medial measurements showed significant difference between the region of interest (ROI): 1 and 4, 5, 6 (p = 0.001, p = 0.001, p = 0.001), 2 and 4, 5, 6 (p = 0.007, p = 0.001, p = 0.001), 3 and 5, 6 (p = 0.001, p = 0.001), 4 and 5, 6 (p = 0.010, p = 0.001). Antero-posterior measurements showed significant difference between the ROI: 1 and 8 (p = 0.031).

CONCLUSION

The posterior-medial acromion close to the AC joint revealed the highest BMD with an increasing density from lateral to medial. In combination with thickness measurements this region would support additional anatomical fixation of the AC joint using bone tunnels if necessary.

CLINICAL RELEVANCE

To anatomically reproduce the insertions of the AC ligaments at the acromion, either bone tunnels or anchors are needed. Therefore, several techniques have been developed. This study provides the anatomical data for these techniques and confirms the reconstructive approach of techniques using anatomical points of fixation and orientation.

Orthopedic applications of acellular human dermal allograft for shoulder and elbow surgery

Shoulder and elbow tendon injuries are some of the most challenging problems to treat surgically. Tendon repairs in the upper extremity can be complicated by poor tendon quality and, often times, poor healing. Extracellular matrices, such as human dermal allografts, have been used to augment tendon repairs in shoulder and elbow surgery. The indications and surgical techniques regarding the use of human dermal allograft continue to evolve. This article reviews the basic science, rationale for use, and surgical applications of human dermal allograft in shoulder and elbow tendon injuries.

Management of acromioclavicular joint injuries

Although recent advances have been made in the treatment of acromioclavicular (AC) joint injuries, they are still challenging for shoulder surgeons. There is a consensus that type I and II injuries should be treated nonoperatively, whereas acute type IV, V, and VI injuries should be treated surgically. There is no algorithm for correctly diagnosing and treating type III injuries, but the current trend is toward nonoperative treatment except for those with persistent symptoms and functional limitations after a course of conservative management. If surgery is indicated, newer anatomic techniques of reconstructing the coracoclavicular (CC) and AC ligaments are recommended.

Coracoclavicular ligament reconstruction: a systematic review and a biomechanical study of a triple endobutton technique

Operative intervention is recommended for complete acromioclavicular (AC) joint dislocation to restore AC stability, but the best operative technique is still controversial. Twelve fresh-frozen male cadaveric shoulders (average age, 62.8±7.8 years) were equally divided into endobutton versus the modified Weaver-Dunn groups. Each potted scapula and clavicle was fixed in a custom made jig to allow translation and load to failure testing using a Zwick BZ2.5/TS1S material testing machine (Zwick/Roell Co, Germany). A systematic review of 21 studies evaluating reconstructive methods for coracoclavicular or AC joints using a cadaveric model was also performed. From our biomechanical study, after ligament reconstruction, the triple endobutton technique demonstrated superior, anterior, and posterior displacements similar to that of the intact state (P>0.05). In the modified Weaver-Dunn reconstruction group, however, there was significantly greater anterior (P<0.001) and posterior (P=0.003) translation after ligament reconstruction. In addition, there was no significant difference after reconstruction between failure load of the triple endobutton group and that of the intact state (686.88 vs 684.9 N, P>0.05), whereas the failure load after the modified Weaver-Dunn reconstruction was decreased compared with the intact state (171.64 vs 640.86 N, P<0.001). From our systematic review of 21 studies, which involved comparison of the modified Weaver-Dunn technique with other methods, the majority showed that the modified Weaver-Dunn procedure had significantly (P<.05) greater laxity than other methods including the endobutton technique. The triple endobutton reconstruction proved superior to the modified Weaver-Dunn technique in restoration of AC joint stability and strength. Triple endobutton reconstruction of the coracoclavicular ligament is superior to the modified Weaver-Dunn reconstruction in controlling both superior and anteroposterior displacements with a failure load that approximates the intact ligament.

Rotational and translational stability of different methods for direct acromioclavicular ligament repair in anatomic acromioclavicular joint reconstruction

BACKGROUND

Many reconstructions of acromioclavicular (AC) joint dislocations have focused on the coracoclavicular (CC) ligaments and neglected the functional contribution of the AC ligaments and the deltotrapezial fascia.

PURPOSE

To compare the modifications of previously published methods for direct AC reconstruction in addition to a CC reconstruction. The hypothesis was that there would be significant differences within the variations of surgical reconstructions.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 24 cadaveric shoulders were tested with a servohydraulic testing system. Two digitizing cameras evaluated the 3-dimensional movement. All reconstructions were based on a CC reconstruction using 2 clavicle tunnels and a tendon graft. The following techniques were used to reconstruct the AC ligaments: a graft was shuttled underneath the AC joint back from anterior and again sutured to the acromial side of the joint (group 1), a graft was fixed intramedullary in the acromion and distal clavicle (group 2), a graft was passed over the acromion and into an acromial tunnel (group 3), and a FiberTape was fixed in a cruciate configuration (group 4). Anterior, posterior, and superior translation, as well as anterior and posterior rotation, were tested.

RESULTS

Group 1 showed significantly less posterior translation compared with the 3 other groups (P < .05) but did not show significant differences compared with the native joint. Groups 3 and 4 demonstrated significantly more posterior translation than the native joint. Group 1 showed significantly less anterior translation compared with groups 2 and 3. Group 3 demonstrated significantly more anterior translation than the native joint. Group 1 demonstrated significantly less superior translation compared with the other groups and with the native joint. The AC joint of group 1 was pulled apart less compared with all other reconstructions. Only group 1 reproduced the native joint for the anterior rotation at the posterior marker. Group 4 showed significantly increased distances for all 3 measure points when the clavicle was rotated posteriorly.

CONCLUSION

Reconstruction of the AC ligament by direct wrapping and suturing of the remaining graft around the AC joint (group 1) was the most stable method and was the only one to show anterior rotation comparable with the native joint. In contrast, the transacromial technique (group 3) showed the most translation and rotation.

CLINICAL RELEVANCE

An anatomic repair should address both the CC ligaments and the AC ligaments to control the optimal physiologic function (translation and rotation).

Surgical treatment of chronic acromioclavicular joint dislocation with autogenous tendon grafts

Background

Conservative treatment of acromioclavicular (AC) joint dislocation is not always successful. A consequence of persistent AC joint dislocation may be chronic pain and discomfort in the shoulder region as well a sensation of constant AC joint instability and impaired shoulder function. Stabilization of the AC joint may reduce these sequels.

Materials and methods

Due to chronic AC joint dislocation, 39 patients in our hospital underwent coracoclavicular (CC) ligament reconstruction with autogenous semitendinosus and gracilis tendons between May 2005 and April 2011. We examined 25 patients after a mean of 4.2 years. The outcomes were Constant shoulder Score (CS), Disabilities of the Arm, Shoulder and Hand (DASH), pain (Visual Analog Scale, VAS), cross-arm test, stability of the AC joint, and complications. The follow-up visits included anteroposterior and axillary radiographs.

Results

Mean CS was 83 in the injured shoulder and 91 in the uninjured shoulder (p = 0.002). Mean DASH was 14. In 14 patients, the AC joint was clinically stable; pain was minor. In radiographs, osteolysis of the lateral clavicle and tunnel widening were markedly common. Fracture of the coracoid process occurred in 5 patients, and 3 suffered a fracture of the clavicle; 2 had a postoperative infection.

Conclusions

Anatomic reconstruction of CC ligaments showed a moderate subjective outcome at the 4-year follow-up. After surgery, almost half the AC joints failed to stabilize. Lateral clavicle osteolysis and tunnel widening were notably common complications.

[Instability pattern of acromioclavicular joint dislocations type Rockwood III: relevance of horizontal instability]

BACKGROUND

There is no evidence-based treatment algorithm established for acromioclavicular joint (AC joint) dislocation classified as type Rockwood III injury. Recent meta-analyses revealed no advantage of surgical treatment compared to the non-operative approach. Both surgical and non-surgical approaches have been reported with inconsistent results. Therefore, the hypothesis of the current study was that patients classified as having Rockwood grade III injury may have different degrees of horizontal AC joint instability.

MATERIAL AND METHODS

A total of 18 consecutive patients who had sustained a dislocation of the AC joint classified as Rockwood III were evaluated radiologically to quantify the horizontal instability of the AC joint. The specific radiological investigation included lateral stress x-rays (Alexander view) und axial stress x-rays with the affected arm in a horizontal adduction position.

RESULTS

The dynamic horizontal instability of the AC joint was found to be independent of the vertical dislocation measured in the Rockwood classification.

CONCLUSION

For further treatment studies Rockwood III injuries should be distinguished in patients presenting with or without a substantial horizontal AC joint instability.

Biomechanical evaluation of a coracoclavicular and acromioclacicular ligament reconstruction technique utilizing a single continuous intramedullary free tendon graft

BACKGROUND

Reconstruction of only the coracoclavicular (CC) ligaments may restore superior-inferior (S-I) but not anterior-posterior (A-P) stability of the acromioclavicular (AC) joint. Concomitant reconstruction of both the AC and CC ligaments may more reliably restore intact biomechanical characteristics of the AC joint.

METHODS

Ten matched pairs of shoulders were utilized. Five specimens underwent CC ligament reconstruction while an equal number underwent combined AC and CC ligament reconstruction utilizing an intramedullary tendon graft. Each of the reconstructions was compared with the intact contralateral control. Translational and load to failure characteristics were compared between groups.

RESULTS

No difference was found in S-I translation between intact specimens and CC-only reconstructions (P = .20) nor between intact specimens and AC/CC reconstructions (P = .33) at 10 Newton (N) loads. Significant differences were noted in A-P translation between intact specimens and CC-only reconstructions (P < .001) but no difference in A-P translation between intact specimens and AC/CC reconstructions (P = .34).

CONCLUSION

The A-P and S-I translational biomechanical characteristics of the AC joint were restored using the new technique described. Reconstruction of the CC ligaments only (versus AC/CC combined) led to significantly increased translational motion in the A-P plane as compared to intact control specimens.

Arthroscopically assisted stabilization of chronic AC-joint instabilities in GraftRope™ technique with an additive horizontal tendon augmentation

PURPOSE

A chronic symptomatic acromioclavicular joint (ACJ) instability is a possible consequence of an acute ACJ separation. Besides vertical instability a horizontal component of the instability is common in high-grade ACJ separation and clinically relevant; especially, in chronic cases. A new technique of horizontal biologic ACJ augmentation with a transacromial gracilis tendon loop as an addition to the arthroscopically assisted stabilization with the GraftRope™ device is described and first clinical and sonographical results are shown.

HYPOTHESIS

The results after arthroscopically assisted single bundle reconstruction of the coracoclavicular (CC) ligaments with an additional horizontal tendon augmentation are comparable to the results of other stabilizing techniques in chronic ACJ instabilities.

METHODS

A consecutive series of 20 patients with chronic symptomatic ACJ instability was stabilized with this new technique. 16 patients were followed-up clinically and sonographically. Patient satisfaction, visual analogue scale (VAS), simple shoulder test (SST), Constant score (CS) and Taft score (TS) were assessed. Bilateral sonographic measurements were performed to evaluate recurrent instabilities. Complications and concomitant glenohumeral injuries were analyzed.

RESULTS

Sixteen patients (n = 2 female, n = 14 male, median age 40 (21-61) years, follow-up rate 84 %) were evaluated median 13 months (range 4-27 months) after indexed operation. 11 patients had a chronic ACJ instability after Rockwood type III, and 5 patients after Rockwood type V lesion. 6 patients suffered a recurrent symptomatic instability after operative treatment. 10 patients of the group were primary stabilized with the new technique. 15 of 16 patients were satisfied with the result of the operation at the follow-up examination. The VAS was median 4.6 of 10 points (range 1.1-7.4 points). The SST reached 9 points (range 5-12 points). The adjusted CS was median 84 % (range 46-93 %) and TS median 9 points (range 5-12 points). The sonographic measurements showed a significant difference in the CC distance between the unaffected and the affected side (21.7 vs. 24.8 mm, p = 0.009). The acromioclavicular distance was median 11 mm (range 7-17 mm) after resection of the lateral clavicle. Concomitant glenohumeral injuries were arthroscopically detected in seven patients. Postoperative complications occurred in one patient (wound infection). In one case, the clavicular washer was removed due to local paresthesia after healing of the graft.

CONCLUSIONS

The arthroscopically assisted stabilization of chronic ACJ instabilities with the GraftRope™ device and an additive horizontal tendon augmentation technique leads to good short-term results with a supplementary horizontal stabilization.

Arthroscopically assisted 2-bundle anatomic reduction of acute acromioclavicular joint separations: 58-month findings

BACKGROUND

Currently, no clinical midterm results have been reported on arthroscopically assisted reduction of the acutely dislocated acromioclavicular (AC) joint using suture-button devices for fixation.

HYPOTHESIS

Athroscopically assisted reduction of the acutely dislocated AC joint yields satisfactory clinical outcomes without loss of reduction, clavicle migration, or AC joint degeneration at midterm follow-up evaluation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The clinical and radiographic outcomes of 23 of 30 consecutive patients (21 men, 2 women) who underwent anatomic reduction for acute AC joint dislocation using 2 suture-button devices between 2006 and 2007 were reviewed. Radiographic evaluation was performed by measurement of coracoclavicular (CC) distance and AC displacement. Clinical evaluation included a visual analog scale (VAS) for pain, the Constant score, the simple shoulder test, and the Short Form-36. Previously, this same patient collective was reviewed after 2 years of follow-up using similar methods.

RESULTS

All 23 patients were available for midterm follow-up examination 58 months postoperatively. There were 3 Rockwood type III, 3 type IV, and 17 type V acromioclavicular joint separations. Mean ± SD follow-up was 58 ± 5.6 months (range, 51-67 months). Most patients (96%) remained very satisfied or satisfied with the procedure outcome. The VAS and Constant score improved significantly when compared with baseline (0.3 ± 0.6 and 91.5 ± 4.7 at 58 months postoperatively vs 4.5 ± 1.9 and 34.5 ± 6.9 at baseline) and remained essentially unchanged when compared with the 2-year outcome scores (0.3 ± 0.6 and 91.5 ± 4.7 at 58 months postoperatively vs 0.25 ± 0.5 and 94.3 ± 3.2 at 2 years). Radiographs showed 8 radiographic failures (undercorrection, posterior displacement, or both) and 4 additional overcorrections of the CC distance. When comparing with 24-month data, 17 of 20 radiographs remained unchanged; 1 case of previous overcorrection drifted into normal AC alignment and 2 cases increased in posterior subluxation of the clavicle.

CONCLUSION

Arthroscopically assisted reduction of the acutely dislocated AC joint provides satisfactory clinical results 58 months after surgery. Compared with the baseline, all patients improved significantly. Two of 23 patients revealed an increased posterior dislocation compared with evaluation 24 months after surgery. No further migration of the clavicle or AC joint degeneration was observed.

Biomechanical evaluation of a novel reverse coracoacromial ligament reconstruction for acromioclavicular joint separation

BACKGROUND

Enhancing anterior-posterior (AP) stability in acromioclavicular (AC) reconstruction may be advantageous.

PURPOSE

To compare the initial stability of AC reconstructions with and without augmentation by either (1) a novel "reverse" coracoacromial (CA) ligament transfer or (2) an intramedullary AC tendon graft.

HYPOTHESIS

Reverse CA transfer will improve AP stability compared with isolated coracoclavicular (CC) reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six matched pairs of cadaveric shoulders underwent distal clavicle resection and CC reconstruction. Displacement (mm) was measured during cyclic loading along AP (±25 N) and superior-inferior (SI; 10-N compression, 70-N tension) axes. Pairs were randomized to receive each augmentation and the same loading protocol applied.

RESULTS

Reverse CA transfer (3.71 ± 1.3 mm, standard error of the mean [SEM]; P = .03) and intramedullary graft (3.41 ± 1.1 mm; P = .03) decreased AP translation compared with CC reconstruction alone. The SI displacement did not differ. Equivalence tests suggest no difference between augmentations in AP or SI restraint.

CONCLUSION

Addition of either reverse CA transfer or intramedullary graft demonstrates improved AP restraint and provides similar SI stability compared with isolated CC reconstruction.

CLINICAL RELEVANCE

Reverse CA ligament transfer may be a reasonable alternative to a free tendon graft to augment AP restraint in AC reconstruction.