After the long period of development of surgery and devices for the treatment of lateral malleolus fracture, surgical techniques have been standardized as anatomical reduction and internal firm fixation. However, the postoperative rehabilitation protocols currently used vary considerably. Thus far, only a limited number of specific rehabilitation studies have assessed this approach according to fracture site and pattern.
A cadaveric study demonstrated no significant fracture displacement, hardware failure, or occurrence of new fractures in cases of unstable ankle fracture after ORIF with an axial compression load . When applying early weight bearing in patients, surgeons should exercise caution regarding the displacement of the fracture site and union. Such concerns may interfere with the decision to apply this rehabilitation approach, especially for less experienced surgeons.
The initiation of weight bearing is accelerated for numerous reasons. First, the application of early weight bearing may accelerate the return of the patient to independent daily life and work. Gul et al. reported that patients who underwent early weight bearing were associated with a significantly more rapid return to work than those who did not undergo early weight bearing. In the present study, significant differences in the shortened hospitalization duration and time to return to work were observed (IWB group vs. DWB group: 5.7 vs. 8.0 days and 6.0 vs. 8.0 months, respectively). Second, joint stiffness may be prevented. Sondenaa et al. confirmed limited ankle range of motion in a postoperative ankle fracture immobilized for 6 weeks with plaster cast. In our scoring system, we found a significant difference in the sport factor evaluated at 3 months after surgery (IWB group vs. DWB group: 75.5 vs. 68.5 points, respectively). We assumed that the patient was unable to exercise because of the limitation of joint motion. Finally, other advantages (i.e., prevention of muscle wasting and osteoporosis) are expected. However, these effects have not been investigated thus far [11, 12].
In our study, we found no significant differences in postoperative radiological outcome and complications between the two groups. Notably, fewer patients had complications (i.e., infection, wound problem, displacement, and delayed union) in the IWB and DWB groups, respectively. These findings demonstrate that the IWB rehabilitation protocol has more advantages than the DWB protocol. Furthermore, we confirmed the benefits of shortening the time to return to work and hospital stay with the IWB rehabilitation protocols. Our study conclusively revealed that these benefits and safety assessment may have significant impacts on the decision of surgeons to allow weight bearing.
This study was characterized by limitations. First, we could not obtain sufficient data regarding functional outcome. Data related to range of joint motion and time of full weight bearing would be helpful in confirming the benefit and verifying the hypothesis. As parameters of muscle weakness and osteoporosis, muscle mass and bone density after rehabilitation protocol must also be measured in future studies. Second, we could not assess patient compliance. Although the differences were not statistically significant, 4 patients in the IWB group reported postoperative pain after weight bearing for 2 weeks after surgery. Although this was not confirmed, the occurrence of pain may have affected the compliance of the patients. Therefore, investigators should devise strategies to improve patient compliance. Third, the study design is the retrospective chart review, which makes it impossible to randomly assign the patients into two groups. However, since the rehabilitation protocol was applied differently as IWB starting from 2016, there is no selection bias. Finally, our study only involved patients with lateral malleolar ankle fractures. On the basis of the data obtained from a randomized controlled trial, the postoperative rehabilitation method for each fracture pattern should be standardized.
In our study, we found no significant differences between the two groups in terms of postoperative radiological outcomes and complications. The benefits of shortening the time to return to work and hospital stay with the IWB rehabilitation protocol were confirmed. In conclusion, application of immediate weight bearing after surgery is recommended for patients with a lateral malleolus fracture who had undergone anatomical reduction and firm fixation.