The surgical treatment of Neer type IIb distal clavicle fracture includes three categories: internal fixation of the distal clavicle, CC ligament reconstruction, and a combination of both. Although all of these methods have been reported to achieve positive clinical results, none has been shown to be superior to the others.
Commonly used operative techniques for internal fixation of distal clavicle fractures include transacromial K-wire or Knowles pin fixation, distal clavicle anatomic locking plate, and hook plate. Until now, many orthopedic surgeons have recommended anatomic locking plates to treat type IIb fracture, and satisfactory clinical results and high union rates have been obtained. However, some argue that in Neer type IIb fractures the lateral fragment is often too small and comminuted to accommodate enough screws and the fixation may not provide sufficient mechanical strength. The biomechanical studies of Madsen et al. showed that the distal fragment of type IIb distal clavicle fractures needs at least five-screw fixation to effectively withstand the moderate force required for rehabilitation training (40 to 80 N) after surgery. Therefore, the authors implied that the plate-and-screw construct alone was not sufficient when it was not possible to obtain fixation with 5 screws in the small or comminuted distal fragment. [22, 23] An alternative option is a hook plate mounted on the medial fragment of the fracture that serves as a lever below the acromion. Screws can be implanted on the distal end of the plate to enhance fixation. Unfortunately, this frequently used method is associated with a higher complication rate than other methods. Complications include AC joint arthritis, shoulder dysfunction, acromion impingement, rotator cuff injury, and stress fracture.[24–26] Therefore, consensus has been reached on the need to remove the implant approximately 8 to 12 weeks postoperatively. 
Some Neer type IIb distal clavicle fractures are treated with CC ligament reconstruction without supplemental fixation. Commonly used techniques include cerclage wire, coracoid loop, suture anchors, double Endobutton plates, and tendon grafts.  Motamedi et al  suggested that there was no significant difference in mean failure load and mean stiffness between the intact CC ligament complex and commonly used augmentations, such as braided polydioxanone and polyethylene. However, Shin et al  reported one case of nonunion and two cases of delayed union in a series of 19 patients who had distal clavicle fractures associated with CC ligament disruption treated surgically with two suture anchors combined with two nonabsorbable suture tension bands. The use of CC ligament reconstruction alone cannot provide the rigid fixation that is required for fracture healing and early joint mobilization. The potential risk of fixing type IIb distal clavicle fractures merely with CC ligament reconstruction includes insufficient fixation strength, loss of facture reduction, and fracture displacement. Especially in cases where the lateral fragments are highly displaced and the surrounding soft tissues, such as the fascia of the deltoid and trapezius muscle, are compromised, CC ligament reconstruction alone is likely to lead to nonunion or delayed union.
From a biomechanical perspective, the importance of the CC ligaments in controlling superior and horizontal translation of the AC joint has been elucidated.  Given the unstable characteristics of the Neer type IIb distal clavicle fracture, the mainstream therapy has shifted to use locking plates with additional CC fixation.  In Neer type IIb fractures, CC ligament injuries result in significant displacement of the fracture fragments. Previous biomechanical studies have shown that the reconstruction of CC ligament could reduce the forces on the internal fixation, and the use of a locking plate with CC fixation could provide better fracture stability than the use of either alone. [22, 31, 32] The combination of an anatomic plate with CC fixation could lead to increased fracture healing rates and reduced failure rates. 
In our institution, we previously treated Neer type IIb distal clavicle fractures with an anatomic locking plate and double buttons. Although this approach provided satisfactory clinical results, there were drawbacks. Because the locking plate was wide and occupied most of the space, the button was usually placed above or beneath the locking plate (Fig. 3), which could cause galvanic effect. Alternatively, the button could be placed anterior or posterior to the locking plate, but iatrogenic clavicle fractures were likely to occur. Moreover, if the position of the button deviated from the middle line of the clavicle, it was likely to cause cutting of the loop.
In this study, we used a miniature locking plate and a single Endobutton as a system to treat Neer type IIb distal clavicle fractures. This approach provides the following benefits: (1) A modified fixation system that includes a miniature locking plate and a single button can fix the fracture and reconstruct the CC ligament simultaneously. (2) The miniature locking plate provides 2.5-mm locking screw holes on the distal end, smaller in diameter than the 2.7-mm holes on most anatomic locking plates. The smaller diameter allows more screw implantation to increase purchase in the bone and obtain adequate fixation. (3) Because the miniature plate is thin and narrow, the loop stitch can be tied around the miniature locking plate, which avoids the conflict of plate setup and reduces the expense of the implant. (4) The button provides more rigid fixation than a suture anchor, reducing the risk of loosening. We treated 7 patients with this system, and no loosening or implant failure was observed during follow-up.
Our study was not without limitations. Because the study was retrospective with prospective follow-up, it was affected by selection bias. Although the results were promising, the sample size was small and there was no control group. Final follow-up was obtained in all cases, but outcomes at long-term follow-up remain to be seen.