AC separation is a common injury of the shoulder. The literature clearly shows that low-grade Rockwood types I–II lesions are best managed conservatively. The data in this survey correlate well with 99% of surgeons choosing conservative treatment [13]. For high-grade AC injuries, operative treatment is clearly supported in the literature. This nationwide survey again correlates with over 96% of surgeons preferring surgical care. Consistent with Tauber et al. [14], this approach is the preferred treatment option of trauma and orthopedic surgeons.
In contrast, treatment recommendations for type III lesions are not conclusive. Both conservative and surgical treatment strategies have been advocated [6]. Further, when choosing surgical care, no surgical gold standard exists. This national survey showed that 58% of surgeons would treat type III lesions surgically. Open, minimally invasive and also arthroscopic techniques have both advantages and disadvantages. In Europe, ORIF using a hook plate, AC reconstruction using MINAR technology as well as arthroscopic interventions have prevailed.
In our study, hook plate osteosynthesis and arthroscopic procedures were most commonly used with 41.1% and 26.8% of surgeons using these techniques, respectively. The current literature shows no significant clinical differences in outcome, but a tendency toward better results and higher patient acceptance is seen with arthroscopic procedures [15,16,17]. Stein et al. have also recently shown improved Taft and Constant scores 2 years postoperatively in patients with high-grade AC separations treated either arthroscopically with a CC-stabilizing double button suture or hook-plating. Further, CC stabilization showed decreased rates of persistent horizontal instability vs. patients treated with a hook plate [18]. Arirachakaran et al. showed that hook plate fixation have lower functional shoulder scores and higher postoperative pain when compared with a loop suspensory fixation [19]. However, hook plates may be combined with ligament reconstruction. For example, Yin et al. concluded that hook plating combined with a double-tunnel CC reconstruction showed superior results to hook plating alone [20]. Although hook plate osteosynthesis is a simple procedure, a second procedure for hardware removal is required. This treatment option is, therefore, quite expensive and arthroscopic procedures are significantly less expensive.
In addition, hook plating has been associated with an increased risk of recurrence with some studies showing a recurrence rate of 2.9% after removal of the plate [15]. In contrast, the MADOK AC reconstruction technique has shown recurrence rates as low as 0% [21]. This procedure uses an allograft sling with reinforcing internal sutures passed around the coracoid and passed through the clavicle for an anatomical CC reconstruction. In addition, the superior AC ligaments are reconstructed with a docking mechanism, with allograft reconstruction of the native AC ligaments.
The MINAR technique is used by 6.2% of surgeons surveyed and CC cerclage with non-resorbable materials are utilized by 3.1% of surgeons. Patient satisfaction and postoperative pain levels are lower with suture rather than metal implants. Darabos et al. [22], for example, showed greater satisfaction and lower discomfort with AC suture reconstruction than with Bosworth screw osteosynthesis. While Bosworth screws are no longer used in isolation, they are still sometimes combined with other treatment modalities. Tiefenboeck et al. [23] showed that Bosworth screw fixation with additional K-wire stabilization offers good-to-excellent functional outcomes and was well tolerated.
Open transarticular stabilization of the AC joint with and without a cerclage was reported as a preferred treatment by 2.1% of surgeons. While Murphy et al. [24] showed good postoperative stability and range of motion, tension banding and other k-wire transfixation have fallen out of favor due to high complication rates, including K-wire migration [25, 26]. Further, this treatment modality has probably also fallen out of favor due to the availability of better implants and development of newer techniques.
This survey also assessed external factors that support a surgical indication for type III lesions. The most common factors were manual overhead labor or overhead sports activities. In this survey, the majority of surgeons preferred operative treatment of type III lesions. Bajnar et al. also highlighted this tendency [27]. Recent literature also shows that patients treated with double suture button reconstruction were much more likely to return to previous sport activity levels compared to patients treated with hook plating [28].
Half of the surgeons surveyed in this study stated that patient age between 20 and 40 years was a decisive indication for surgery in type III lesions as younger patients are more physically demanding. Patient over 40 years old were not considered as an important indicator for surgery in this survey. With increasing age, both the surgical risk and the comorbidities increase, which probably play an important role in choosing conservative treatment. Presumably, a more defensive attitude towards surgical intervention in older patients may also be a factor.
Due to the complex ligamentous anatomy of the AC joint, a gold standard surgical technique is still elusive. Due to the large number of surgical techniques and extensive research in the field, we assume that no ideal treatment modality exists as no study has been able to show one modality with obviously superior outcomes. The variety of surgical techniques used to treat AC separation in this survey is most likely a result of these factors, but individual training and personal preferences may also play a role. For example, trauma and orthopedic surgeons used different surgical treatment modalities in this study. Half of the trauma surgeons preferred stabilization with hook plate osteosynthesis, while 38% of orthopedic surgeons preferred arthroscopic modalities. This study clearly shows that Swiss surgeons utilize many treatment options for AC joint separation. As the range of modern techniques including arthroscopic or minimally invasive surgical techniques becomes wider, the outcomes of specific procedures need to be further evaluated to finally find an optimal implant and surgical technique to further benefit patients and improve long-term outcomes.