Home / Treatments / Ankle microinstability
Pain on the outer side, low confidence when you plant the foot, and minor twists that keep happening — with scans that "look fine". It has a name, an anatomical explanation and a solution.
For decades the anterior talofibular ligament (the one injured in most sprains) was described as a single structure. The anatomical studies by Vega and Dalmau-Pastor's group showed something different — and clinically decisive: this ligament has two fascicles, present in 100% of the ankles studied, and they don't behave the same way:
The superior fascicle (red) lives inside the joint; the inferior fascicle and calcaneofibular ligament (blues) form one connected complex.
Isolated tear of the intra-articular superior fascicle.
Injury of the full complex (inferior fascicle + calcaneofibular ligament).
Both can be treated — but the first, precisely because it hides from the scans, is the one that leaves so many people with a "badly healed sprain" for months or years.
The first step is always conservative: physiotherapy with strength and proprioception work. When symptoms persist, ankle arthroscopy does two things at once: it confirms the injury by seeing it directly — often invisible on imaging — and repairs it anatomically with anchors in the same procedure, also treating associated findings (synovitis, impingement, cartilage lesions).
The anatomical work by Vega and colleagues (32 ankles dissected plane by plane) laid the foundations of modern ankle ligament surgery:
Its practical consequence: because the whole complex is connected, isolated arthroscopic repair of the anterior talofibular ligament gives excellent results even when the calcaneofibular ligament is also injured — and the arthroscopic technique is biomechanically equivalent to open surgery, with less tissue damage.
The superior fascicle is a thin intra-articular structure that often goes unnoticed on conventional imaging. Its tear causes pain and low confidence without obvious instability — the typical picture of microinstability.
No: physiotherapy with strength and proprioception comes first. Arthroscopy is considered if symptoms persist despite proper rehabilitation.
Microinstability is the isolated tear of the superior fascicle (subtle symptoms); classic instability is injury of the full complex (frank giving-way). Both can be treated.
Not always: sharing an origin and being joined by arciform fibres, repairing the anterior talofibular ligament tensions the whole complex, with excellent results even with both injured. Each case is decided by seeing the injury at arthroscopy.
A specific examination points to the diagnosis at the first visit — even when your scans "look fine".
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