Ankle Instability
Ankle sprains are common injuries and comprise approximately 85% of ankle injuries. It tends to occur in the younger sporty individual, although it can happen to other age groups as well.
Certain factors may predispose an individual to such injuries. A tight gastrocnemius or Achilles tendon, high arch foot, ligamentous laxity, as well as neuromuscular impairment are some of the risk factors which may conspire to bring about this injury.
How does an ankle injury occur?
The Mechanism of Injury is usually that of an ankle inversion type sprain which results in the ankle rolling and injuring the lateral (on the outside) ligaments.
The ATFL or Anterior Talo-Fibular Ligament is injured most of the time. The Calcaneofibular Ligament (CFL) is also often injured in concert.
These are two of the more important ligaments that confer stability and once they’re rendered incompetent, the patient experiences the symptoms of the ankle sprain quite regularly.
Symptoms of an ankle injury
The patient may present with pain on bearing weight, especially if the injury is acute. There’s associated swelling of the ankle which may demonstrate signs of bruising as well.
How is an ankle injury diagnosed and treated?
It may be prudent to obtain an X-ray as a baseline radiological investigation in order to assess if there’s a fracture. Clinical assessment corroborates the suspicion and there is tenderness on palpation of the ATFL or CFL ligaments.
If the ankle is very swollen, however, it may not lend itself to accurate testing of the integrity of the ligaments. Treatment involves conferring stability to the injured ankle while allowing the pain and swelling to subside. This may be achieved with a suitable ankle brace or a Walker-Boot, or even a Bivalved cast.
In the chronic injury, the ankle may not be as exquisitely tender. The patient may not even complain of an obvious recent incident of trauma. However, they may complain of a nagging pain after standing or walking certain distances.
The clinical examination may not show tenderness over the ATFL or CFL per se, however, they may complain of tenderness over palpation of the talar dome. Tests of the integrity of the ligaments will demonstrate impairment.
X-rays and perhaps an MRI/CT may be required to look for possible Osteochondral Lesions (OCL) and other injured structures. Conservative management is prescribed as above.
However, the clinician is cognizant that the ligaments are incompetent and the patient’s symptoms may continue to deteriorate. If the patient does not do well with conservative management and has a high-demand lifestyle, surgery is a consideration. Ankle instability is not entirely innocuous and can sometimes lead to early onset of arthritis, particularly if osteochondral lesions are already present.
The modified Brostrum-Gould procedure we advocate is a percutaneous one. The wounds are considerably smaller and this technique allows us to test the strength of the reconstruction.
Therapeutic ankle arthroscopy is often performed at the same sitting to assess the joint for concurrent damage. If an OCL is present it can be addressed as well. This is a day surgery procedure and the patient is discharged for follow-up in the clinic, with a walker-boot or cast. The usual target is to return to normal walking within the month and sports at 3 months.
Intraoperative testing of strength of reconstruction
Dr Tay’s method of reconstructing the ligaments allows testing of the strength of the reconstruction intra-operatively.
Figure 1. Photos showing incisions from percutaneous Brostrum-Gould technique which was done together with O-arm guided drilling of the Tibial Osteochondral Lesion.
Figure 2a. Retrograde Drilling of OCL with O-arm guidance.
Figure 2b. Retrograde Drilling of OCL with O-arm guidance.
