Suture Button Fixation Constructs for Acromioclavicular Joint Dislocation: A Systematic Review and Descriptive Meta-Analysis of Three Configurations

The shoulder is a marvel of engineering, a ball-and-socket joint that allows for a vast range of motion, but its upper connection point is surprisingly fragile. Where the collarbone meets the shoulder blade, a small but critical ligament complex acts as a tether, holding the two bones in perfect alignment. When a hard fall or a direct blow tears these ligaments, the collarbone can pop upward, creating a visible bump and significant pain. This injury, known as an acromioclavicular joint dislocation, is common among athletes and active individuals. For severe cases, surgeons must restore that tether to keep the bones from drifting apart again. Over the last two decades, the preferred method has shifted away from rigid metal plates that often require a second surgery to remove, toward a more flexible approach using strong, non-absorbable threads anchored by small metal buttons. These buttons sit on the top of the collarbone and the coracoid process, a hook-like bone below, with the thread pulling them together to mimic the natural ligament.

Despite the popularity of this flexible fixation method, surgeons have developed three distinct ways to arrange the threads and buttons, and until now, no one had systematically compared how these different arrangements actually perform in patients. One method uses a single loop of thread with two buttons; another uses a modified double loop with three buttons; and the third uses two independent loops with four buttons, designed to perfectly match the anatomy of the natural ligaments. The choice between them has largely been a matter of personal preference, as there was no clear evidence to say which configuration offered the best stability or the quickest recovery. A new systematic review set out to map the landscape of these three options, gathering data from dozens of studies to see if one design truly outshines the others.

The researchers began by scouring medical databases for every study that reported on patients treated with these suture button techniques. They found twenty-five studies, encompassing roughly 1,340 patients, all published between 2012 and 2025. It is important to note that the quality of this evidence is limited; every single study included was either a retrospective review of past records or a case series, meaning no study had directly randomized patients to one of the three methods to compare them head-to-head. The researchers treated the data as a collection of individual stories rather than a single controlled experiment, calculating the average outcomes for each of the three button configurations separately. They looked at how long the surgeries took, how much pain patients felt a year later, how well they could use their shoulders, and how often the joint slipped out of place again.

When the researchers tallied the results, a clear pattern emerged regarding the trade-offs between speed and stability. The simplest configuration, using a single loop and two buttons, was the fastest to perform, taking an average of 54 minutes in the operating room. However, this speed came with a higher risk of the joint slipping back out of place, with a redislocation rate of about 8.3 percent. The most complex configuration, which uses two independent loops and four buttons to recreate the natural anatomy, took the longest to perform at 77 minutes. Yet, this extra time appeared to pay off in stability. Patients with this dual-loop design reported the least amount of pain, achieved the highest functional scores for shoulder movement, and had the lowest rate of the joint slipping back out, at just 2.5 percent. They also required the fewest follow-up surgeries to fix complications.

The middle option, a modified design using three buttons, presented a confusing picture. While it took slightly longer than the simple method, its results were inconsistent, with some studies showing excellent stability and others showing high rates of failure. The data for this specific group was too scattered to draw a firm conclusion about whether it offered a true advantage over the simpler or more complex designs. The researchers also noted that the definition of "failure" varied from study to study; some considered a joint to have failed if it shifted by a tiny amount, while others only counted it as a failure if it shifted significantly. Even when they adjusted for these differences, the trend remained: the most anatomically precise method seemed to offer the best protection against the joint moving out of place, while the simplest method was the quickest to execute.

Despite these numerical differences, the authors are careful not to declare a winner. Because the evidence comes entirely from non-comparative studies, it is impossible to say for certain that the better results of the complex method are due to the hardware itself rather than the skill of the surgeons who tend to use it. The studies with the most complex designs often came from high-volume academic centers with highly experienced surgeons, while the simpler methods were used more broadly. This means the data might reflect the expertise of the medical team as much as the design of the implant. Furthermore, the complex method requires more metal buttons and more drilling, which increases the cost of the procedure. The researchers conclude that while the more complex, anatomical reconstruction appears to offer superior stability and function in the available data, the evidence is not strong enough to recommend it over the simpler, faster options for every patient. The field currently lacks the high-quality, head-to-head trials needed to definitively answer which approach is best, leaving the final decision in the hands of the surgeon and the specific needs of the patient.