Value of MRI in diagnosing injuries after ankle sprains in children.

BACKGROUND

To our knowledge, there are only a few prospective studies on the use of magnetic resonance imaging (MRI) to diagnose injuries associated with ankle sprains in children. We hypothesized that MRI examinations of acute ankle sprains in growing children would show relevant injuries that may have been overlooked by conventional clinical, radiological, and ultrasound examinations.

METHODS

Thirty children with acute inversion injury of the ankle were subjected to an MRI examination of the ankle joint, in addition to conventional radiographic procedures. All data were recorded prospectively. Depending on the severity of the clinical symptoms, the children were divided into three different groups. Children with little soft-tissue swelling and who were still able to walk were assigned to Group I (n = 10), Group II consisted of children who were only partially able to walk and had moderate soft-tissue swelling (n = 12), while Group III consisted of the children who were not able to walk and had pronounced soft-tissue swelling (n = 8). Regular followup examinations were carried out. At the final followup examination, on average 8 months after injury, the children in Groups II and III were again examined by MRI. The clinical results were compared and correlated with the results of the MRI examinations.

RESULTS

Altogether, torn ligaments could be verified in 23 out of 30 of the cases; bony avulsions were found in 10% of these. Three of 30 patients had a Salter I injury. Bone bruising was found in 18 out of 30 (60%). Bone bruising was most commonly found near the medial talus. MRI examination of the patients in Group I showed no more ruptures than the clinical examination; here, only four patients were found to have partial ruptures of the ATL. In Group II, torn ligaments were found in six out of 12 (50%) of the cases; similarly, Salter I injuries were found in three out of 12 cases. The patients in Group III also showed serious injuries on the MRI examination. Bone bruising, torn ligaments, or bony avulsions were found in eight out of eight (100%) cases. The recorded clinical results showed only weak correlation to the injury patterns diagnosed using MRI. Only the bone bruises correlated with clinical results. Children with more pronounced swelling and less ability to walk were more commonly diagnosed with bone bruises. No differences were found between groups with regard to pain, instability, or limitations of mobility in the followup examinations or the final MRI examination 8 months after injury.

CONCLUSION

The injury patterns diagnosed through MRI examination did not correlate with clinical findings. With adequate progressive rehabilitation, the pathological changes diagnosed with MRI healed without further complications. MRI examinations of acute ankle distortion injuries in children did not result in any additional therapeutic value. Therefore, we believe conventional clinical, radiological, and ultrasound diagnostic methods are sufficient for the primary diagnosis of ankle fractures and ankle ligament injuries in children.