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

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.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Case series, LEVEL IV.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE IV

ANATOMICAL AND BIOMECHANICAL ROLE OF STATIC STABILIZERS OF THE ACROMIOCLAVICULAR JOINT

OBJECTIVE

The aim: To determine the anatomical and biomechanical significance of the static stabilizers of the acromioclavicular joint by conducting numerical modeling using the finite element method and experimental investigation.

PATIENTS AND METHODS

Materials and methods: To ensure the study, modeling of the deformation processes of the clavicle and scapula systems with various combinations of ligament damage was conducted. The COMPAS-3D software package was used to build the simulation model, which allowed obtaining models that are closest to reality. To verify the results of the numerical modeling, corresponding studies of the mechanical characteristics and determination of the stiffness of the investigated systems were carried out using the upgraded TIRAtest-2151 testing stand.

RESULTS

Results: The stiffest system is the system in which all ligaments are intact, and the sequence of decreasing stiffness of the system is presented in the following order: damage to lig. trapezoideum; lig. conoideum; lig. claviculo-acoacromiale inferior; lig. claviculo-acoacromiale superior; the coracoclavicular ligament complex; the acromioclavicular ligament complex.

CONCLUSION

Conclusions: Static stabilizers in general, and their components in particular, are characterized by significant anatomical and functional features. The natural stabilization of the acromioclavicular joint is provided by their synergistic interaction, which is the basis for the development and implementation of surgical interventions, the scope of which includes the restoration of both ligament complexes. The loss of stiffness in the «clavicle-scapula» system is significantly more pronounced when lig. acromioclaviculare superior and inferior are damaged (8.5 N/mm) than when lig. conoideum and lig. trapezoideum are damaged (11.6 N/mm).

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.