Clinical and Radiological Outcomes of Closed-Loop, Double Button, Coracoclavicular Fixation for Extralateral (Neer Type IIC) Fractures of the Distal Clavicle.

Background: The distal end of the clavicle accounts for 10-28% of all clavicle fractures of which 52.8% are considered displaced and require internal fixation due to their high percentage of non-union. Numerous surgical techniques have been described for the well-known Neer types IIA, IIB, and V. Still, the literature is scarce for the rare "extralateral" (type IIC) fracture where the fracture line is located lateral to the completely torn coracoclavicular (CC) ligaments; such small fractures are sometimes not amenable for standard locking plate fixation.

Methods: We present a series of seven patients treated surgically with closed-looped double button CC stabilization via an open approach. There were four males and three females with a mean age of 31 years (range: 19-46 years). The mechanism of injury was a motor vehicle accident in four cases and a fall from height in three cases. The average time from injury to surgery was 2.7 ± 1.3 days and the average follow-up period was 25.7 months (range: 16-48 months). A custom-made, closed-looped, double button device was made using the ProCinch Adjustable Cortical Fixation for anterior cruciate ligament (ACL) (Stryker, Kalamazoo, Michigan) and another standard or slotted button. The fracture was reduced anatomically and the device was tightened and secured with five to six knots. In two cases, additional interfragmentary sutures were used for extra stability. Postoperatively, the arm was immobilized in a simple sling for four weeks; passive assisted elevation up to 90 degrees was allowed from the second postoperative week, followed by active elevation after the sixth postoperative week. Radiological outcomes (bony union, loss of reduction, implant mispositioning, or subsidence of buttons) were assessed using serial plain radiographs. The Constant score (CS) and the Acromioclavicular Joint Instability Score (AJIS) were used for the final clinical evaluation, at least one year postoperatively.

Results: Bony union was achieved in all patients at a mean time of 2.7 months (range: 2.5-3.6 months). No cases of delayed union, loss of reduction, button migration, or subsidence were noted. The mean CS was 96.6 ± 3.4 and the mean AJIS score was 94.1 ± 4.7 in a mean follow-up period of 25.7 months (range: 16-48 months). One patient developed a hypertrophic scar and another had mild skin irritation by the suture knots; no other complications were noted except for one patient who developed an early superficial skin infection managed with antibiotics and debridement under local anesthesia. Four patients who participated in sports before injury were able to regain almost full activity seven to nine months after the operation. All were satisfied with the final result. Two patients showed ossification of the CC ligaments with no significant clinical implications.

Conclusions: Although we retrospectively reviewed a small series of patients, we were able to demonstrate a complete rate of fracture union and excellent clinical outcomes with no major complications. Type IIC distal clavicle fractures are rare and require special attention in terms of reduction and optimal fixation. Open CC fixation with closed-looped double buttons is a relatively easy and reproducible technique. We advocate the readjustment of Neer's classification, including "extralateral" fractures as a IIC subtype.