Ankle instability

Last evidence check May 2014

Principal authors Jim Barrie, Rebecca Hope and Jo Lishman

Non-surgical management

Most papers on surgery for chronic instability comment that "the patients had full non-surgical treatment before being considered for surgery" and this is considered good practice (Karlsson and Lansinger 1993, Trevino et al 1994).

However only one published series examined the effect of functional rehabilitation on chronic instability. Karlsson (1991a) found that 50% of patients with chronic instability benefited from rehabilitation. Patients with mechanical instability were less likely to benefit than those with purely functional instability.


Functional ankle instability often resolves after arthroscopic debridement of synovitis


The studies of Schafer and Hintermann (1996), Kibler (1996), Ogilvie-Harris et al (1997), Okuda (2005) and Ferkel (2007) found a high incidence of intra-articular pathology:

About a quarter of intra-articular lesions were not identified pre-operatively.

Laing et al (2004) found that arthroscopic treatment of intra-articular lesions avoided the need for surgery in 50% of patients with demonstrated mechanical instability.

It is our practice to offer an examination under anaesthesia, stress radiographs and arthroscopy to all patients with persisting functional instability after a functional rehabilitation programme. This allows us to treat intra-articular pathology and identify those with mechanical instability who can be offered a stabilisation procedure. It also identifies the small group with combined ankle and subtalar instability for whom a Sammarco tenodesis rather than a modified Brostrom procedure is appropriate. Approximately 40% of our patients have had only an arthroscopic procedure. Patients with mechanically stable ankles and other intra-articular problems have generally had good results from arthroscopic surgery. Patients with unstable ankles will be offered a stabilisation procedure. We prefer to perform this about 6 weeks after the arthroscopy rather than at the same sitting because of the amount of swelling that tends to accompany an ankle arthroscopy.


There are two main approaches to surgical stabilisation:

Biomechanical studies (Liu and Baker 1994, Hollis et al 1995, Bahr 1997, Schmidt 2004, Fujii 2006) show that, if anything, the Brostrom-Gould procedure confers more stability and more normal ankle kinematics than any of the non-anatomical tendon grafts. The Bahr anatomical tendon graft also produced kinematics close to normal.

There have been two randomised controlled trials comparing the Brostrom to non-anatomical reconstructions. Both had significant methodological deficiencies. Neither showed any difference in functional outcome between the trial groups.

Longitudinal studies of single procedures report:

Because it is simple, restores near-normal ankle kinematics and has a fuller long-term clinical outcome evidence base than the anatomical tendon grafts, we advise that the Brostrom procedure is to be preferred in the average patient. For the more complex case we offer the Sammarco anatomical tenodesis, accepting that further long-term results may influence this advice. Indications for the Sammarco procedure include:

Post-op management

Standard post-operative regimes after ankle ligament reconstruction involve 4-6 weeks in a below-knee cast, sometimes with a period of non-weightbearing. Karlsson (1995, 1999) reported trials comparing casting with walker boots and ankle braces, finding no deterioration in outcome with these simpler and more comfortable supports. Wearing a plaster cast is not necessary after an ankle ligament reconstruction and delays functional recovery. We manage our patients in functional braces from the beginning, except for an initial 48 hours splintage in a backslab to allow post-op swelling to settle.