SLR - August 2019 - Lenny Nguyen

Lower Signal Intensity of the Anterior Talofibular Ligament Is Associated with a Higher Rate of Return to Sport After ATFL Repair for Chronic Lateral Ankle Instability
 
Reference: Li, H., Hua, Y., Feng, S., Li, H., & Chen, S. Lower Signal Intensity of the Anterior Talofibular Ligament Is Associated with a Higher Rate of Return to Sport After ATFL Repair for Chronic Lateral Ankle Instability. The American Journal of Sports Medicine. 2019 Jun 27.

Scientific Literature Review


Reviewed By: Lenny Nguyen, DPM
Residency Program: NYU Langone Hospital – Brooklyn, NY

Podiatric Relevance: Ankle sprains are one of the common injuries seen by podiatrists. Patients that present with chronic ankle instability often need surgical repair of the anterior talofibular ligament (ATFL), with the modified Brostrom being the most common form of repair. On MRI, intact ATFLs show low signal/noise ratio (SNR), while injured and thickened ATFLs show high SNR. The purpose of this study was to quantitatively evaluate SNR value related to functional outcomes after ATFL repair in patients with chronic lateral ankle instability.  

Methods: The cohort study looked at patients with chronic ankle instability who underwent open ATFL repair between January 2009 and August 2014. Inclusion criteria included patients who received open ATFL repair, an ATFL remnant confirmed by arthroscopy and MRI, and preoperative MRI studies. Exclusion criteria included patients with absent ATFL, an avulsion at the fibular or talar attachment, osteochondral defect, and obvious bony deformity. Participants were separated into two groups: High SNR (>10.4) and low SNR (<10.4). Functional outcomes were based on the American Orthopaedic Foot and Ankle Society (AOFAS) score, Karlsson Ankle Functional Score (KAFS), and Tegner Activity scale.  

Results: 70 patients were chosen for the final study: 33 in the low SNR group and 37 in the high SNR group. No significant difference was detected in terms of AOFAS score, KAFS, or Tegner Activity Scale preoperatively. Postoperatively, no significant difference was noted in terms of the AOFAS score. For the KAFS and Tegner activity scale, the low SNR group had significantly higher scores than the High SNR group. Also, patients within the low SNR group had a significantly higher return to sports than the high SNR group.

Conclusions: This cohort study demonstrates, patients with a lower signal intensity of the ATFL on MRI had a better functional outcome based on the KAFS and Tegner activity scale. The low SNR group also had a higher return to sport. Preoperatively assessing a patient’s SNR may allow for better surgical planning. Other strategies may be considered, such as augmentation, if a patient has high SNR. 

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