Abstract
Purpose
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To evaluate the clinical and biomechanical evidence for the addition of acromioclavicular (AC) ligament repair and reconstruction in the surgical management of high-grade AC joint (ACJ) dislocation.
Methods
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This is a systematic review of biomechanical and clinical studies that describe AC reconstructive or reparative techniques. The search ranged from 1946 to 2024 and included OVID, MEDLINE, PubMed, CINAHL, Embase, Google Scholar and the Cochrane Library databases. Clinical and biomechanical outcomes were evaluated.
Results
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Thirty-two eligible studies were identified. Of these, four biomechanical studies focused on the ACJ exclusively. Twenty-eight other studies (15 clinical and 13 biomechanical) were identified involving reconstruction of the ACJ in addition to the treatment of the coracoclavicular (CC) ligaments. There was clinical evidence of improved outcomes with ACJ repair and reconstruction, although comparison was difficult. In comparative studies, ACJ-specific Taft and acromioclavicular joint instability scores were improved in patients with ACJ reconstruction. Constant score and subjective shoulder value also increased, although this was observed in studies lacking a control group. The biomechanical studies provide evidence of increased translational and rotational stability with ACJ repair and reconstruction, but the optimal technique has not been identified.
Conclusion
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ACJ repair and reconstruction, in addition to CC repair, results in improved biomechanical and functional outcomes and should be considered when treating high-grade ACJ injuries. There is insufficient evidence in the literature to be able to recommend a specific technique to treat ACJ injuries.
Introduction
The acromioclavicular (AC) joint (ACJ) complex comprises the ACJ, the AC ligaments and the coracoclavicular (CC) ligaments. Injuries to the ACJ were subdivided into six types by Rockwood (1). Non-operative treatment is indicated in type 1 and 2 injuries. The management of type 3 injuries remains controversial (2).
The CC ligaments mainly stabilise the joint in the superior–inferior plane, but the ACJ is primarily responsible for stability in the anterior–posterior plane. In addition, the capsular structures also contribute to the strut function of the clavicle for guiding the rotation of the scapula (3). As a consequence, surgery is indicated in severe (type 4–6) injuries (4).
Although over 150 different ACJ repair techniques have been described (5), none of these have been demonstrated to be an optimal intervention. Traditionally, only the CC ligaments have been addressed, but continued horizontal instability occurs in 18% of high-grade injuries treated with either arthroscopic CC joint (CCJ) stabilisation or a hook plate (6), and only 86.2% of grade V injuries return to their pre-existing level of sport (7). This suggests that these interventions alone may be insufficient, and more recently, attention has been focussed on the ACJ capsule itself with the rationale being that the additional reconstruction provides improved stability (8, 9, 10) and raises the following question: should we do more to address the ACJ itself?
The aim of this review is to assess the evidence base behind both repair and reconstruction of the AC ligaments with three questions being asked: is there any biomechanical evidence that ACJ repair or reconstruction increases construct stability in acute or chronic repairs? If so, which configuration confers the greatest mechanical stability? Is there any clinical evidence that ACJ repair/reconstruction + CC reconstruction (CCR) is better than CCR alone?
Methods
Eligibility criteria
All papers involving patients older than 16 years of age were eligible. Cadaveric and biomechanical studies were included.
Information sources
The literature was searched between 1946 and 10 July 2024 in OVID, MEDLINE, PubMed and Embase. Google Scholar, the Cochrane Library and CINAHL databases were searched.
Search
All databases were searched with identical search terms: ACJ ligaments OR ACJ capsule OR AC ligaments OR AC capsule AND reconstruction OR biomechanics.
The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Fig. 1). The Methodological Index for Non-Randomised Studies (MINORS) (11) tool was used to appraise all non-randomised clinical studies. A summary of the studies subcategorised by type is included (Table 1).
A summary of the studies subcategorised by type.
Biomechanical evidence* | Clinical evidence* | |
---|---|---|
Isolated ACJ | Morikawa et al. (25), Freedman et al. (24), Peeters et al. (26), Ibrahim et al. (27) | |
ACJ + CCR | Shu et al. (18), Garg et al. (22), Beitzel et al. (21), Saier et al. (15) | Hessman et al. (8), Tienen et al. (39), Sobhy et al. (33), Jensen et al. (31), Li et al. (32), Kibler et al. (30), De Beer et al. (34), Hann et al. (29),Liu et al. (36), Huang et al. (35), Voss et al. (28), Iban et al. (37), Mori et al. (38) |
ACJ + CCR vs CCR | Deshmukh et al. (13), Michlitsch et al. (19), Gonzalez et al. (20), Weiser et al. (17), Dyrna et al. (14), Theopold et al. (16), Schar et al. (5), Morikawa et al. (23), France et al. (12) | Barth et al. (9), Tauber et al. (10) |
Studies evaluating different techniques.
Study selection
Studies identified by the electronic search were screened initially by title to include papers that described repair/reconstruction of the ACJ in isolation or with CC ligament repair and exclude any topics unrelated to the question posed by the study. Articles were only selected if they answered one of the three key questions listed above. General review articles, expert opinions and anatomical and biomechanical studies were excluded as they would not objectively answer the questions we posed. Duplicate articles were excluded. Additional papers identified from references were also included. The articles were assessed by two independent reviewers (AK and DT), and any differences in article inclusion were discussed and resolved by consensus. There were multiple standardised outcome measures in the studies identified. The number of joints, duration of follow-up, outcome measures and results were identified. As the majority of studies were technical papers showing success or feasibility of novel techniques, we acknowledge that there will be a degree of reporting bias, given that published articles are more likely to publish positive results and data collection was heterogeneous.
Results
Two hundred thirty-five studies were identified. Following initial screening, 203 papers were excluded as they were irrelevant to the research question. Thirty-two full-text articles were included in the final review.
There were two broad categories: clinical studies and cadaveric/simulated biomechanical studies. The simulation studies were then divided into those describing ACJ in isolation and those including ACJ in addition to the treatment of the CCJ.
Biomechanical studies
A total of 17 biomechanical studies were identified, using both cadaveric and bone-block models. A variety of different measurement techniques resulted in a range of outcome measures being detected. These are subdivided into those addressing the ACJ in isolation and those in which it was used as an augment for a CC ligament repair/reconstruction. The latter group is summarised in Table 2.
Biomechanical studies considering ACJR as an augment to CC ligament reconstruction.
Study | Study type | Techniques studied | Joints studied, n | Outcome measures | Outcomes |
---|---|---|---|---|---|
Garg et al. (22) | Cadaveric | Intramedullary vs extramedullary reconstruction of the ACJ | 6 | AP/SID/LTF | Intramedullary reconstruction of the ACJ provides greater stability in the anteroposterior direction and improved load-to-failure characteristics |
Schar et al. (5) | Sawbone | DTRC vs BiPod vs DTR | 18 | PS elongation/LTF and stiffness | The DTRC and the DTR group resulted in similar low elongation, while the elongation in the BiPod technique was slightly higher |
Beitzel et al. (21) | Cadaveric | Shuttle graft, intramedullary graft, cruciate configuration, acromial tunnel | 24 | 3D movement (rotation) | Shuttle graft was the most stable method showing anterior rotation comparable to the native joint |
Dyrna et al. (14) | Cadaveric | Anterior, superior, posterior, O-frame and X-frame | 30 | 3D movement (rotation) | Native translational stability could be restored by the addition of AC capsule augmentation, while partial rotational instability remained. No significant individual differences in results |
Shu et al. (18) | Cadaveric | ACJR ± augmentation by either (1) CA ligament transfer or (2) an intramedullary AC tendon graft | 6 | AP/SID | Either technique demonstrated improved AP restraint and provided similar SI stability compared with the isolated CCR |
Deshmukh et al. (13) | Cadaveric | Native ligaments vs Weaver–Dunn vs augmentation | 21 | AP/SID/LTF | Supplementation with AC augmentation is superior to Weaver–Dunn but inferior to native ligaments |
Morikawa et al. (23) | Cadaveric | DA vs CCLR vs DA+ CCLR | 6 | Posterior translation and rotation | ACLC+ACCR closest restoration to translational and rotational stability |
Saier et al. (15) | Cadaveric | ACJ cerclage + CCLR vs CCLR alone | 12 | Horizontal ACJ translation, before and after loading | Combined ACJ and CCR adequately re-established physiological horizontal ACJ stability |
Gonzalez et al. (20) | Cadaveric | CC alone vs CC and ACJ repair | 12 | A/P and SID | Reconstruction of both the CC and AC ligaments demonstrates significantly greater initial horizontal stability than isolated CCR |
Michlitsch et al. (19) | Cadaveric | Modified Weaver–Dunn vs free-tissue graft reconstruction of the AC and CC ligaments | 6 | Yield strength of repair, A/P and SID | Mean ultimate and yield loads and linear stiffness for the AC + CC reconstruction were greater than the modified Weaver–Dunn reconstruction (did not reach statistical significance) |
Theopold et al. (16) | Cadaveric | DCT vs DCT + AC | 21 | Horizontal displacement | No significant difference in the total displacement |
Weiser et al. (17) | Cadaveric | DTR vs DTR + ACR vs STR + ACR vs PDSS + ACR | 24 | Rotational stiffness, LTF | No significantly increased stability with AC repair |
France et al. (12) | Cadaveric | LARS vs LockDown vs Endobutton vs Neoligament | 2 | AP/SI/horizontal pivot | AC ligament repair significantly improves the stability of the construct and significantly reduces the vertical (SI) and horizontal (AP) instability. This surgical technique closely replicates the native joint in vitro |
AC, acromioclavicular; ACJR, ACJ reconstruction; ACR, AC repair; AP, anteroposterior, A/P, anterior/posterior; CCLR, CCL reconstruction; CCR, CC reconstruction; DA, dermal allograft; DCT, double coracoclavicular tunnel technique; DTR, double tightrope; LTF, load to failure; PS, posterosuperior; PDSS, PDS sling; SID, superioinferior displacement; STR, single tightrope.
Evaluation of ACJ reconstruction as an augment to CC ligament reconstruction
A number of studies analysed the biomechanical properties of an augment. No standardised measurement technique or parameters were defined, resulting in potentially conflicting results.
France et al. (12) augmented a number of CC ligament reconstruction techniques with the addition of interosseous horizontal mattress sutures. They observed that such methods in isolation allowed 2–4 times more translation than the native joint in the horizontal plane. All implants had improved horizontal stability with the addition of intraosseous AC ligament repair. The combined augmented repair closely resembled a native joint in terms of stability, but the authors were unable to comment on the clinical significance of these findings.
Deshmukh et al. (13) compared the native ligaments to a Weaver–Dunn with or without ACJ reconstruction using a variety of techniques and concluded that ACJ reconstruction was superior to Weaver–Dunn but inferior to native ligaments. Dyrna et al. (14) investigated five different ACJ reconstruction techniques in an intact CC model, all of which significantly increased the resistance to posterior translation, but partial rotational instability remained when compared to the intact specimen. The tested constructs revealed no significant individual differences.
Saier et al. (15) compared the addition of an ACJ suture tape cerclage in a modified Figure-of-8 fashion to anatomical CC ligament reconstruction. They concluded that only combined CCR and ACJ repair was able to adequately recreate physiological horizontal ACJ stability.
Both Theopold et al. (16) and Weiser et al. (17) concluded that there was no significantly increased stability in comparison with reconstructions without direct AC repair. The former employed an AC cerclage technique, and the latter employed a PDS drilled through holes in both the acromion and the clavicle. Weiser and coworkers acknowledged that this may represent either the surgical technique or the measurement tools being insufficient to measure the differences.
Schär et al. (5) compared CCR, ACJ reconstruction and a ‘BiPod’ technique using poly-tape to secure both the CC and the AC, concluding that elongation in the BiPod technique was slightly higher.
Several studies investigated the role of an intra-articular graft as an augment. Shu et al. (18), Mischlitsch et al. (19) and Gonzalez-Lomas et al. (20) concluded that the intra-articular graft provided better results than the isolated CC ligament reconstruction. Beitzel et al. (21) compared an intramedullary augment to two wrap techniques and concluded that the ‘shuttled wrap’ was superior in controlling rotation. Garg et al. (22) compared both intramedullary and extramedullary techniques to reconstruct the ACJ as an augment to CCJ repair. Intramedullary reconstruction of the ACJ provided greater stability in the anteroposterior direction and improved load-to-failure characteristics. Morikawa et al. (23) reconstructed the superior ACJ complex using a dermal allograft and found that augmentation of the CC ligament repair was able to closely restore the percent of normal posterior translational and rotational stability present in the native ACJ.
Biomechanical evaluation of AC repair and reconstruction in isolation
Four papers that focussed on the ACJ in isolation were identified. Two were cadaveric, and two were non-cadaveric.
These are summarised in Table 3.
Evaluation of ACJ reconstruction in isolation.
Study | Study type | Techniques studied | Joints studied, n | Planes of movement tested | Outcomes |
---|---|---|---|---|---|
Freedman et al. (24) | Cadaveric | Intramedullary semitendinosus graft | 12 | Superior–inferior/AP and compressive loads | Reconstruction with the graft had similar properties in AP/LAT translation and load to failure |
Peeters et al. (26) | Foam block | Nice knot, Nicky’s knot, surgical knot | 40 sawbones | Superior–inferior translation, translation, latero-lateral translation | The nice knot in combination with bone anchors provides the strongest compression |
Morikawa et al. (25) | Cadaveric | Repair of each 1/3 of the ACJ and comparison | 15 | Translation/rotation | Surgical techniques restoring the entire superior ACLC address both posterior translational and rotational stability of the ACJ |
Ibrahim et al. (27) | Sawbone | FiberTape, vs FiberWire vs(under–over) suture technique | 24 | Superior, anterior and posterior translation | The under–over suture bridge technique was found to be superior |
AC, acromioclavicular; ACJ, AC joint; AP, anteroposterior.
Freedman et al. (24) investigated a similar intramedullary technique to that used by both Mischlitz and Gonzalez. They found that the reconstructed specimens reproduced the stability of the intact specimens during all translational and joint compression load trials and partially reproduced load-to-failure characteristics.
Morikawa et al. (25) concluded that repair of the anterior two-third of the joint was most important for restoring the posterior translational stability, whereas repair of the anterior and posterior one-third of the joint was most important for the rotational stability.
The final two biomechanical studies were performed in a non-cadaveric setting.
Peeters and coworkers (26) evaluated different stabilisation techniques on a polyurethane foam block AC model. The nice knot in combination with bone anchors provided the strongest compressive forces across the ACJ, and a transosseous technique demonstrated more resistance to translation than the anchor technique.
Ibrahim et al. (27) used a sawbone model and a ‘suture bridge configuration’ and an ‘under–over’ technique. The authors concluded that the under–over technique was superior to the suture bridge technique. As these studies were performed in a non-biological setting, it is not possible to make any recommendations regarding their ability to stabilise an injured ACJ or even the feasibility of undertaking them in a patient.
The biomechanical studies are difficult to compare as different testing protocols and outcome measures were used. The majority of the studies confirm the improved AP stability with augmentation. Reference is made to inferior control of rotational stability unless the anterior and posterior one-third of the joint is augmented.
Clinical studies
Fifteen papers were identified. These consisted of both prospective and retrospective case series. The number of joints involved varied between 2 and 116. There was heterogeneity between the papers with regard to the severity of injuries and outcome measures.
The MINORS (11) tool was used to appraise the clinical studies and assess their quality. Some of these studies were non-comparative, so only the first section of the scoring system was used. The global ideal score was 16 for non-comparative studies and 24 for comparative studies. These are summarised in Table 4.
Clinical studies appraised by the MINORS system.
Study | Non-comparative study criteria* | Comparative study criteria† | Total | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | ||
Tienen et al. (39) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 14/16 |
Iban et al. (37) | 2 | 1 | 2 | 2 | 2 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 13/16 |
Mori et al. (38) | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 12/16 |
Liu et al. (36) | 2 | 2 | 2 | 2 | 1 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 13/16 |
Huang et al. (35) | 2 | 2 | 0 | 2 | 1 | 2 | 0 | 0 | N/A | N/A | N/A | N/A | 9/16 |
Voss et al. (28) | 2 | 2 | 2 | 2 | 1 | 2 | 0 | 0 | 2 | 2 | 1 | 2 | 18/24 |
Hessmann et al. (8) | 2 | 2 | 2 | 2 | 2 | 2 | 0 | 0 | N/A | N/A | N/A | N/A | 12/16 |
De Beer et al. (34) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 14/16 |
Kibler et al. (30) | 2 | 2 | 2 | 2 | 2 | 1 | 2 | 0 | 2 | 2 | 2 | 2 | 21/24 |
Barth et al. (9) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 0 | 2 | 2 | 0 | 2 | 20/24 |
Hann et al. (29) | 2 | 2 | 2 | 2 | 0 | 2 | 0 | 2 | N/A | N/A | N/A | N/A | 12/16 |
Jensen et al. (31) | 2 | 2 | 2 | 2 | 2 | 2 | 0 | 0 | N/A | N/A | N/A | N/A | 12/16 |
Li et al. (32) | 2 | 2 | 0 | 2 | 0 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 10/16 |
Tauber et al. (10) | 1 | 1 | 2 | 1 | 2 | 2 | 2 | 0 | N/A | N/A | N/A | N/A | 11/16 |
Sobhy et al. (33) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 0 | 2 | 0 | 2 | 2 | 20/24 |
Criteria for non-comparative studies were as follows - 1: a stated aim of the study; 2: inclusion of consecutive patients; 3: prospective collection of data; 4: endpoint appropriate to the study aim; 5: unbiased evaluation of endpoints; 6: follow-up period appropriate to the major endpoint; 7: loss to follow-up not exceeding 5%; 8: prospective calculation of the study size.
Criteria for comparative studies were as follows - 9: a control group having the gold standard intervention; 10: contemporary groups; 11: baseline equivalence of groups; 12: adequate statistical analysis.
Barth et al. (9) presented the results of one of the three comparative studies identified, reporting on 116 patients. The CC was stabilised using a double Endobutton in 93%, and concomitant ACJ reconstruction was performed in 50%. They concluded that quality of reduction and functional outcome were improved by ACJ reconstruction; however, several techniques were used to achieve this. Due to the wide range of techniques involved, it is only possible to draw the more general conclusion that ACJ reconstruction provides benefit rather than any specifics regarding techniques.
Tauber et al. (10) published a cohort study of 26 patients, comparing isolated CCR with CCR augmented with ACJ reconstruction using a semitendinosus tendon. The shoulder-specific outcome scores were the same in both groups, but the ACJ-specific Taft and acromioclavicular joint instability (ACJI) scores were improved in the group with ACJ reconstruction. In addition, 75% of the ACJ reconstruction group had horizontal stability compared to the 29% treated with CCR alone. The potential criticism of this paper is the use of the unvalidated Taft and ACJI scores (Fig. 2).
ACJ augmentation described by Tauber et al. (10).
Citation: EFORT Open Reviews 10, 2; 10.1530/EOR-2023-0121
Voss et al. (28) conducted a study on 30 patients, examining the effect of the addition of cerclage repair of the ACJ to the isolated CC ligament repair. Both groups showed good clinical results at 2-year follow-up. AC distances increased in both groups from the post-surgery measurement to the 2-year follow-up but were lower with the addition of AC cerclage. CC distances did not increase significantly over time in both groups.
Hann et al. (29) described the clinical results in 59 patients with grade V ACJ injury treated with an arthroscopic CC double-button technique with the addition of an AC cerclage for ACJ repair. Constant score (CS), subjective shoulder value, Taft score and ACJI score were all used as outcome measures in addition to AP translation. The described technique yielded good radiological results with a lower incidence of dynamic posterior translation and improved clinical outcomes. It is notable that there was no control group used in the study. Multiple ACJ scores were used. These have had little validation, and therefore, it is hard to make recommendations based on them. That having been said, this paper provides clinical and radiographical evidence that this technique is effective at treating severe dislocations of the ACJ (Fig. 3.).
Double-button technique as described by Hann et al. (29).
Citation: EFORT Open Reviews 10, 2; 10.1530/EOR-2023-0121
Kibler et al. (30), Jensen et al. (31), Li et al. (32), Sobhy et al. (33), De Beer et al. (34) and Huang et al. (35) all presented small case series (6–16 patients) using varying techniques and outcome measures, including VAS, CS, Taft and DASH. All described good outcomes; however, there were no control groups in any of these series. It is therefore not possible to draw any conclusions regarding any advantages of ACJ reconstruction from these studies.
Likewise, Hessmann et al. (8) reported 88.9% ‘good’ or ‘excellent’ results at 2–7 years in 64 patients after ACJ reconstruction with PDS bands, but the absence of any outcome measures makes it impossible to draw any conclusions from this study.
Liu et al. (36) assessed the augmentation of CC ligament reconstruction with the use of suture anchors to repair the ACJ in a prospective study of 29 patients. Although functional outcomes were improved and the horizontal stability of the joint was maintained with this technique, the absence of a control group means that the clinical superiority of this technique over CC ligament reconstruction alone cannot be proven using this study. The same can be said of the study of Ruiz Ibán et al. (37) conducted in 2023, which also yielded good clinical outcomes but lacked a comparative group.
Mori et al. (38) preformed a retrospective study on 21 patients with chronic ACJ dislocations. CC ligament reconstruction with a ‘Dog Bone’ construct was augmented by ACJ reconstruction with a tendon autograft. It is noteworthy that vertical–horizontal ACJ instability was observed in five shoulders. However, there was no significant correlation between the increase in CCD and clinical scores at the final follow-up.
Tienen et al. (39) followed up a series of 21 competitive athletes with grade V dislocations and treated them with a surgical technique that combined a CA ligament transfer with ACJ reconstruction using a braided suture cord material. Clinical outcomes were largely positive, although unfortunately, the absence of a control group once again limits the use of this study’s findings.
Discussion
Many papers have been published on the management of ACJ dislocation. A vast majority described the techniques that address CC ligaments, but very few have addressed the management of the joint itself. Only four studies have investigated the management of the ACJ in isolation. The clinical studies are mostly small case series. The outcome measures are variable, and not all relate specifically to the ACJ. Only three studies (9, 10) described a control group, and only one (10) of these used a consistent reconstruction technique. This paper also utilised multiple scoring systems and currently provides the best clinical evidence.
Barth et al. (9) concluded that the anatomical outcome (i.e. quality of reduction) correlated with the functional outcome. This finding was at odds with the suggestion by some authors (40) that secondary loss of reduction may have no effect on functional outcomes. This may reflect the inability of the current clinical outcome scores to adequately measure ACJ instability.
Reintgen et al. (41) identified 16 different outcome scores, many of which were generic shoulder measures. They also identified a number of ACJ-specific scores, including the Taft score, the Nottingham clavicle score (42) and the ACJI score (43), none of which had been validated. The authors concluded that ‘inconsistent reporting of multiple outcome measures is present in the ACJ injury literature’ and recommended that, at the present time, multiple scores be used. Among the cadaveric studies, the outcome measures differed. Some measured displacement, while others assessed load to failure. Many of the studies found statistically significant improvements in horizontal, but not rotational stability (14) of the joint in their repair or reconstructive models; however, it has not been demonstrated that these improvements translate to better clinical outcomes. This may be explained by the observation that techniques addressing the CCJ alone and those that repair the ACJ are both able to withstand supraphysiological loads in biomechanical studies (44).
With regard to the four papers related to management of the ACJ in isolation, the paper by Morikawa et al. (25) is the only study that identifies the components of the ACJ complex and addresses them.
Jordan et al. (45) conducted a systematic review of the literature in 2018, which included six biomechanical and 12 clinical studies. Four of these studies reported either constant or ASES scores after AC augmentation. The authors concluded that CCR with ACJ augmentation resulted in improved horizontal stability in both biomechanical and clinical studies. However, they also reported that a comparative study had shown no clinical advantage with respect to ASES and CS scores. The authors concluded that their systematic review did not support AC augmentation in routine clinical practice. Closer scrutiny of the review reveals that this may not be an entirely valid statement. Their conclusion is drawn from the analysis of one paper (by Tauber et al. (10)), which described no difference in shoulder-specific outcome scores (ASES and CS) but did identify an improvement in ACJ-specific Taft and ACJI scores. Tauber and coworkers indicated that these scoring systems represent ACJ-related complaints in a more adequate manner than non-ACJ-specific shoulder scores.
In effect, although the paper includes the term ‘acromioclavicular joint augmentation’ in its title, most of the studies included did not address the ACJ specifically. They also did not include a number of studies that did describe augmentation or repair of the ACJ capsule. As a consequence, the conclusions drawn are not supported by the evidence provided in that paper.
It can be seen that, although a variety of techniques exist, the evidence in the clinical literature is poor. As a consequence, it is not possible to state that ‘comparative studies have shown no clinical advantage’ as was stated by Jordan et al. (45) but rather that the evidence has not been presented, which would make a clinical comparison possible. The evidence presented by Barth et al. (9) and Tauber et al. (10) suggests that the addition of ACJ reconstruction to CCR is beneficial.
Conclusion
A number of biomechanical studies provide evidence that there is greater AP stability and rotational stability if the ACJ augmentation is added to CCR.
It is difficult to conclude which repair configuration confers the greatest stability to the ACJ. Many of the studies addressed only AP stability. There is evidence that rotational stability requires the whole of the ACJ complex to be addressed and that a technique that includes both the anterior and superior/posterior aspects of the joint would control both translation and rotation. There is no evidence, clinical or biomechanical, of the superiority of any of the techniques described. At the current time, the authors would recommend adopting the technically simpler procedures if ACJ repair or reconstruction is to be performed.
We conclude that there is no strong clinical evidence to support or refute the use of ACJ augmentation in the management of ACJ dislocation in the acute setting. Despite the flaws that have been discussed above, there are comparative studies that support the addition of ACJ reconstruction and none that do not.
On the basis of the current evidence, the authors recommend that consideration be given to the addition of ACJ repair or reconstruction to CCR for acute grade IV–VI ACJ dislocations. The caveat is that further biomechanical and clinical studies need to be undertaken and that consistent reporting of outcomes needs to be used if progress is to be made in improving outcomes in the management of ACJ injuries.
Supplementary materials
This is linked to the online version of the paper at https://doi.org/10.1530/EOR-2023-0121.
Declaration of interest
The authors received no financial or material support for the research, authorship and/or publication of this article. D Tennent receives royalties and payments for teaching from Arthrex, which do not have any relationship to the subject of this study.
Funding
This work did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.
Author contribution statement
Al-A Khoriati helped in data curation, formal analysis, investigation, methodology and writing original draft and editing. T Antonios wrote and edited the manuscript. Z A Fozo contributed to data curation, formal analysis, investigation, methodology, writing original draft and editing and project administration. A Choudhury took part in data curation, investigation and project administration. M Arnander and E Pearse supervised the study and wrote and edited the manuscript. A senior author, D Tennent was involved in conceptualisation, investigation, supervision, visualisation and writing.
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