Abstract

BACKGROUND:

Many patients report feeling functional ankle instability, despite having no clinically demonstrable lateral instability.

HYPOTHESIS:

Some patients who experience functional instability of the ankle have substantial abnormalities of the anterior talofibular ligament despite having apparently normal lateral laxity in clinical examination.

STUDY DESIGN:

Case series; Level of evidence, 4.

METHODS:

Fourteen patients who had functional ankle instability after sprain, despite having no clinically demonstrable lateral instability, were included in this study. All subjects underwent standard stress radiography, magnetic resonance imaging, and ankle arthroscopy. These patients were treated with anatomical reconstruction of the anterior talofibular ligament.

RESULTS:

Arthroscopic assessment revealed 3 cases with no ligamentous structure with scar tissue, 9 cases with partial ligament tears and scar tissue on the disrupted anterior talofibular ligament fiber, and 2 cases of abnormal course of the ligament at the fibular or talar attachment. Magnetic resonance imaging revealed the following: 5 cases of discontinuity of the anterior talofibular ligament, 2 cases of narrowing of the anterior talofibular ligament, 4 cases of high-intensity lesion in the anterior talofibular ligament, and 3 normal cases. The mean American Orthopaedic Foot and Ankle Society Ankle Hindfoot scale score was 66.2 +/- 3.2 points at preoperation and 92.3 +/- 4.4 points 2 years after surgery.

CONCLUSION:

All patients in this study with functional ankle instability, despite their having no demonstrable abnormal lateral laxity, had morphologic ligamentous abnormality on arthroscopic assessment.