In the present study, we identified three significant factors affecting the progression of AJS, which were preoperative serum glucose level, injury mechanism, and duration of surgery. These results supported our hypothesis that elevated preoperative serum glucose level and high-energy injury are related to the progression of AJS.
A previous study has reported that preoperative serum glucose levels could affect the formation of fracture blisters. Quavedo et al.1 found that the presence of postoperative blisters in ankle fracture was associated with prolonged surgical procedures and high serum glucose levels. Blister formation is proposed to result from the increased interstitial pressure of post-traumatic swelling. This decreases the cohesion between epidermal cells and facilitates fluid transport into the blister cavity.7 Diabetic patients are prone to nonenzymatic glycosylation and are exposed to glycation end products. These products lead to the disjunction and abnormal function of soft tissues.8 Four patients were diagnosed with diabetes in this study. However, two of the four diagnosed patients had normal preoperative serum glucose levels. It can be assumed that serum glucose levels before surgery are relevant rather than whether diabetes is diagnosed. In comparison with patients who simply fell, patients injured by traffic accidents showed a tendency of swelling. A previous study reported a significantly higher incidence of perioperative soft tissue complications after high-energy trauma and primary soft tissue injury.9 Varela et al. showed an association between high-energy injury and the formation of fracture blisters.10 The duration of surgery was also correlated with AJS in this study. Usually, surgeons try to shorten the surgical time to prevent infection, soft tissue damage, tourniquet syndrome, etc. Surgical time is often prolonged by the difficulty in reducing swelling. It is known that a series of processes for reducing fracture fragments can cause soft tissue damage, and the swelling is more severe.11
Swelling is a normal body defense mechanism that responds to fractures. Due to swelling, substances and cells for fracture healing are sent to the fracture site, and unstable sites can be mechanically protected. However, if the healing process is excessive, it can have an adverse effect. Excessive fluid retention can cause blisters and infections at surgical sites. Moreover, persistent inflammation and swelling can cause muscle atrophy around the joints and a decrease in physical ability. To reduce the adverse effect caused by severe swelling, immediate reduction, immobilization, elevation, and urgent surgery should be performed as soon as possible after trauma. Furthermore, close observation of the surgical wound is required.
There are several limitations in our study. First, it is unclear whether the radiological measurement results are representative of AJS. If techniques such as figure-of-eight and water volumetry methods were used, a more accurate result could be obtained.12 Second, we defined the postoperative 2 weeks of device removal radiograph of the ankle joint as indicating a normal status. However, even at that time, swelling can still be caused by an incision at the surgical site. If we can obtain a contralateral radiograph of the ankle at the point of injury, a more accurate comparison would have been possible. Finally, the study was conducted retrospectively. A study comparing more variables with randomized controlled trials should be conducted.
This is the first study of factors affecting swelling in fracture patients. In this study, only ankle fracture was assessed; however, the results could be applied to other fracture areas. In particular, the findings may be applicable to forearm and leg fractures, where compartment syndrome is common. For patients with swelling-related factors, we could prevent more severe swelling and determine whether urgent surgery is required.