The acromioclavicular ligament shows an early and dynamic healing response following acute traumatic rupture

Current trends in surgical treatment of the acromioclavicular joint injuries in 2023: a review of the literature

Background

This article examines the wide range of surgical reconstruction options available for acromioclavicular (AC) joint injuries. However, the lack of consensus regarding the most suitable surgical techniques is attributed to the high and variable failure rates observed with current approaches.

Methods

This article presents a comprehensive overview of the current surgical principles and techniques used by renowned experts in the field of AC shoulder injury management.

Results

It emphasizes the significance of addressing horizontal and rotational instability in AC injuries and highlights the impact of impaired scapular biomechanics.

Conclusion

By exploring these emerging concepts and strategies, the article aims to lay the foundation for future studies aimed at improving treatment outcomes and patient management.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Level of evidence IV.

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL RELEVANCE

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

Ligament injury in adult zebrafish triggers ECM remodeling and cell dedifferentiation for scar-free regeneration

After traumatic injury, healing of mammalian ligaments is typically associated with fibrotic scarring as opposed to scar-free regeneration. In contrast, here we show that the ligament supporting the jaw joint of adult zebrafish is capable of rapid and complete scar-free healing. Following surgical transection of the jaw joint ligament, we observe breakdown of ligament tissue adjacent to the cut sites, expansion of mesenchymal tissue within the wound site, and then remodeling of extracellular matrix (ECM) to a normal ligament morphology. Lineage tracing of mature ligamentocytes following transection shows that they dedifferentiate, undergo cell cycle re-entry, and contribute to the regenerated ligament. Single-cell RNA sequencing of the regenerating ligament reveals dynamic expression of ECM genes in neural-crest-derived mesenchymal cells, as well as diverse immune cells expressing the endopeptidase-encoding gene legumain. Analysis of legumain mutant zebrafish shows a requirement for early ECM remodeling and efficient ligament regeneration. Our study establishes a new model of adult scar-free ligament regeneration and highlights roles of immune-mesenchyme cross-talk in ECM remodeling that initiates regeneration.

Ligament injury in adult zebrafish triggers ECM remodeling and cell dedifferentiation for scar-free regeneration

After traumatic injury, healing of mammalian ligaments is typically associated with fibrotic scarring as opposed to scar-free regeneration. In contrast, here we show that the ligament supporting the jaw joint of adult zebrafish is capable of rapid and complete scar-free healing. Following surgical transection of the jaw joint ligament, we observe breakdown of ligament tissue adjacent to the cut sites, expansion of mesenchymal tissue within the wound site, and then remodeling of extracellular matrix (ECM) to a normal ligament morphology. Lineage tracing of mature ligamentocytes following transection shows that they dedifferentiate, undergo cell cycle re-entry, and contribute to the regenerated ligament. Single-cell RNA sequencing of the regenerating ligament reveals dynamic expression of ECM genes in neural-crest-derived mesenchymal cells, as well as diverse immune cells expressing the endopeptidase-encoding gene legumain . Analysis of legumain mutant zebrafish shows a requirement for early ECM remodeling and efficient ligament regeneration. Our study establishes a new model of adult scar-free ligament regeneration and highlights roles of immune-mesenchyme cross-talk in ECM remodeling that initiates regeneration.

Highlights

Rapid regeneration of the jaw joint ligament in adult zebrafishDedifferentiation of mature ligamentocytes contributes to regenerationscRNAseq reveals dynamic ECM remodeling and immune activation during regenerationRequirement of Legumain for ECM remodeling and ligament healing.

Superior clinical results for early arthroscopic treatment of grade IIIb and V acromioclavicular joint instability compared to delayed operative treatment

BACKGROUND

Arthroscopy-assisted cortical fixation devices have been increasingly used in the operative management of both acute and chronic cases of acromioclavicular joint instability (ACJI). It has been hypothesized that delayed surgical management leads to inferior clinical and radiologic outcomes compared to acute treatment. The purpose of this study is to compare clinical and radiologic outcomes, scapula dyskinesia, and failure or revision rates of arthroscopically treated acute and chronic ACJI.

METHODS

This retrospective study of prospectively collected data included all surgically treated patients with grade IIIb and V chronic ACJI between 2013 and 2017, matched 1:1 to a group of acute grade IIIb and V ACJI patients treated during the same time period. Chronic ACJI was defined as delayed surgical treatment >21 days after injury. Chronic cases received an additional hamstring autograft next to the suture pulley systems. Follow-up was obtained at an average of 3.2 years (range: 1.4-6.2). Clinical outcome scores included the Constant-Murley Score (CMS), Taft Score (TF), Nottingham Clavicle Score (NCS), ACJI Score, Sick Scapula Score (SSS), Subjective Shoulder Value (SSV), Subjective Shoulder Test (SST), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, and the visual analog scale pain score. Radiologic follow-up was obtained pre- and postoperatively and at final follow-up. The 2-year results were compared to the results of a 1:1 matched-pair group comprising patients who were treated with an acute ACJI during the same period.

RESULTS

Thirty-three (80.5%) of 41 chronic ACJI cases were available for follow-up and were compared with 33 matched-pair cases of acute ACJI (of 41). The clinical scores were significantly better in the acute cohort for the CMS (92 ± 8 vs. 88 ± 8, P = .030), ASES (91 ± 13 vs. 85 ± 13, P = .002), SSS (1.4 ± 1.6 vs. 3.4 ± 2.5, P = .0004), NCS (86 ± 13 vs. 81 ± 13, P = .049), TF (9.9 ± 1.9 vs. 9.0 ± 2.1, P = .030), and ACJI (83 ± 13 vs. 75 ± 1, P = .003). In contrast to the chronic cohort, the acute cohort illustrated a significant loss of reduction at follow-up (P = .020).

CONCLUSION

Based on the results of this study, early arthroscopy-assisted operative treatment of grade IIIb and V ACJIs seems superior to delayed surgical intervention of grade IIIb and V ACJIs. Furthermore, an additional autograft loop leads to less loss of reduction compared with suture pulley/suspensory loop fixation standalones.

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.

Arthroscopic-Assisted Coracoclavicular Stabilization With Anchorless Transosseous Double-Row Acromioclavicular Ligament Complex Repair: The Acute Acromioclavicular Joint Dislocation

The current concept procedures in the acute acromioclavicular joint dislocation should be divided into 2 types of structure restoration: those that provide coracoclavicular stabilization, which affects the primary healing of the coracoclavicular ligaments by vertically stabilizing the clavicle and coracoid in their anatomical positions, and those that attempt to repair the superior acromioclavicular ligament complex, which controls both horizontal and rotational stabilization. The acute acromioclavicular joint dislocation clinical outcome will be achieved if you perform both procedures. It's difficult to stabilize the acromioclavicular joint in both vertical and horizontal planes, and most current techniques aren't always effective. In this Technical Note, we discuss an arthroscopic-assisted technique that reconstructs the coracoclavicular and acromioclavicular ligaments under image intensifier guidance to achieve bidirectional (vertical and horizontal) and rotational stability.

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.

Arthroscopic Anatomical Acromioclavicular Joint Reconstruction using a Button Device and a Semitendinosus Graft

Objective

To report a new technique for anatomical acromioclavicular (AC) joint reconstruction.

Methods

In order to minimize such complications, the authors describe a new anatomical and biological AC joint repair. This technique aims to provide greater stability by using two anatomically placed clavicular tunnels and a combined construct with a double endobutton cortical fixation for primary stabilization, and to be biologically advantageous by using an autologous semitendinosus (ST) tendon graft. Additionally, the coracoclavicular ligament reconstruction is complemented with an AC joint cerclage and capsular reinforcement, which will protect the biological construction in its initial stage of healing.

Results

This technique provides adequate primary and secondary biomechanical stability by passing both a semitendinosus autogenous graft and a double endobutton device, through anatomically placed and small diameter clavicle holes, without the need for coracoid drilling. Our technique showed encouraging results regarding pain resolution, range of motion, and function. At final follow‐up we experienced excellent results with average pain score of 1.6, and average ROM of 159° of forward flexion, 160° of abduction, 68° of external rotation, and internal rotation level at T11. Postoperative function also showed great improvements with average ASES of 85 points, an average Constant Score of 87 and a Subjective Shoulder Value of 89 points. This technique also achieved perfectly acceptable radiographic results, with an average coracoclavicular distance increase of 0.8 mm. Regarding complications, our sample showed one case of AC join subluxation, two cases of internal saphenous nerve injury, and two partial graft tears at the suture‐button interface, with none of these requiring surgical revision.

Conclusion

This technique is advantageous in treatment of acromioclavicular joint dislocation and can be performed in both the subacute and chronic setting.

Ligamentous healing potential of the acromioclavicular ligament following acute anatomical reconstruction

BACKGROUND

Horizontal instability following acute acromioclavicular joint (ACJ) reconstruction still occurs with a high prevalence. Although the human acromioclavicular ligament complex (ACLC) represents the major horizontal ACJ stabilizer, experimental studies on healing characteristics are lacking. Therefore, the purpose of this histological study was to investigate the healing potential of the ACLC following acute anatomical reconstruction METHODS: In this prospective clinical-experimental study, 28 ACLC biopsies were performed in patients with complete ACJ dislocations (Rockwood type 4 or 5) during acute hook plate stabilization (IG: implantation group; n = 14) and hook plate removal (EG: explantation group; n = 14). Histological analyses included Giemsa staining, polarized light microscopy and immunostaining against CD68, αSMA and collagen type I and type III. Histomorphological evaluation entailed cell counts, collagen expression score, ligament tissue maturity index (LTMI) and descriptive analysis of specific ligamentous structures. Statistics consisted of nonparametric Mann-Whitney U tests and a level of significance of P < .05.

RESULTS

Total cell counts (cells/mm² 1491 ± 296 vs. 635 ± 430; P < 0.001) and collagen III expression (3.22 ± 0.22 vs. 1.78 ± 0.41; P < 0.001) were higher in EG compared to IG. Inversely αSMA + (11 ± 9 vs. 179 ± 186; P < 0.001) and CD68 + cell counts (56 ± 20 vs. 100 ± 57; P 0.009) were significantly lower in the EG. The EG revealed a comparable reorientation of ligamentous structures. Consistently, ACLC samples of the EG (21.6 ± 2.4) displayed a high total but differently composed LTMI score (IG: 24.5 ± 1.2; P < 0.001).

CONCLUSIONS

This experimental study proved the ligamentous healing potential of the human ACLC following acute anatomical reconstruction. Histomorphologically, the ACLC reliably showed a ligamentous state of healing at a mean of about 12 weeks after surgery. However, processes of ligamentous remodeling were still evident. These experimental findings support recent clinical data showing superior horizontal ACJ stability with additional AC stabilization in the context of acute ACJ reconstruction. Though, prospective clinical and biomechanical studies are warranted to evaluate influencing factors on ACLC healing and potential impacts of acute ACLC repair on clinical outcome.

STUDY TYPE

Controlled Laboratory Study.