Summary

Ten elite-level athletes were treated with Extracorporeal Shock Wave Therapy (ESWT) for medial malleolar stress fractures. All cases achieved bone healing and returned to competition at 15.5 weeks on average.

Abstract

Objectives:
Medial malleolar stress fracture is a relatively uncommon yet high risk chronic injury which affects athletes who participate in sports requiring repetitive jumping and landing. Although Extracorporeal Shock Wave Therapy (ESWT) has been recognized to be effective for the treatment of non- or delayed union of fractures, there is no published case series in a peer-reviewed journal regarding the use of ESWT for medial malleolar stress fracture. The purpose of this study is to report clinical courses of ten elite-level young athletes with medial malleolar stress fracture who were treated successfully with ESWT.

Methods

From April 2015 to April 2017, ten patients who were diagnosed with medial malleolar stress fracture and treated with ESWT in our institution were included in the study. All ten patients were elite-level athletes, four of them being national team members. 7 were male and 3 were female, ranging in age from 12 to 20 years (mean 15.9). Four of them were skeletally immature athletes with open physis in the distal tibia. The mean follow up period was 12 months. They participated in the following sports: basketball (3), figure skating (2), gymnastics (2), track& field (2) and trampoline (1). Each subject received ESWT in biweekly intervals. At each session, 3000 shocks were applied. Maximum energy flux density ranged from 0.07 to 0.25 mJ/mm2, and total mean energy flux density was 516 mJ/mm2. Our primary assessment of the bone healing was judged by radiography. We also assessed the length of fracture line with coronal and axial view of CT scan, which was compared with radiographic finding. Also at the time when radiographic bone healing was appreciated, we compared with MRI finding and assessed the existence of bone marrow edema in STIR.

Results

All ten cases achieved bone healing and returned to play at the previous level of activity. None of the cases had recurrence after returning to play. From the initiation of ESWT, the mean times of the following were measured: Bone healing was achieved radiographically at 16.2 weeks (ranging 4-32), similarly, resolution of the tenderness in the medial malleolus at 4.6 weeks (ranging 2-12), starting of the running at 5.5 weeks (ranging 2-12), and return to play at 15.5 weeks (ranging 4-36). At the time of the bone healing which was judged by radiography, all cases achieved resolution of the bone marrow edema, however, fracture lines were appreciated with the CT scan in all the cases; the mean length of the residual fracture line was 5.7mm in coronal and 12.1 mm in axial view. Among the four skeletally immature adolescent athletes, there were no premature or delayed closure of the physis and had no growth disturbance during our observation period.

Conclusion

This study indicates ESWT is a safe and viable option to treat medial malleolar stress fracture even with the adolescent athletes with open physis. Although they were elite-level athletes, all of them achieved successful return to play without recurrence. Further prospective studies are needed to support this finding.