DIFFICULT ANKLE Fibular

Lateral malleolus

Anterior talo- fibular ligament

Calcaneo-fibular ligament

Tibia

Anterior tibio-fibular ligament

Talus Neck of talus Cervical ligament

Subtalar ligaments

Inter-osseous talocalcaneal ligament

For talar tilt it is recognised that there should be greater than 9 degrees of talar tilt or more than 3 degrees side to side difference for mechanical instability. Functional instability relates to recurrent ‘giving way’ of the ankle and is a combi- nation of some mechanical laxity of the ligaments associated with a propriocep- tive deficit and muscular weakness result- ing in recurrent inversion injury.

Mechanical instability does not nec- essarily mean functional instability or that this is the source of pain.

Calcaneus

Figure 1: Antero-lateral view of the ligaments of the ankle (deep) ©1999 Primal Pictures Ltd

Calcaneo-cuboid ligaments

with the peroneal tendon sheath and so due consideration should be given to these structures.

About one-fifth of injuries may also have ligamentous lesions in the cal- caneo-cuboid ligaments (Fig.1) and over 40% of Grade II - III ankle lig- ament injuries will have injuries involving the subtalar ligaments.

Assessment A review of the history and initial man- agement is the first place to start.

This may raise the

Was the initial management of the injury appropriate? Was there any previous his- tory of ankle inversion injuries and were they adequately rehabilitated?

Restoration of strength, range of motion and proprioceptive awareness are impera- tive prior to re-learning of sports specific drills.

Protective taping or bracing may

be required in the early stages. A thor- ough review of the rehabilitation process to date is important.

It is

important to get a full description of the mechanism of the injury as well as dis- cussing the forces involved at the time the injury occurred.

possibility of osteochondral injury (involves the articular cartilage and sub- chondral bone) or other fracture.

The degree of difficulty in weight bearing may raise a suspicion.

Did the patient

seek initial medical advice because of the severity of the injury and if so were the Ottawa Ankle Rules (see Issue 1) followed with regards to radiological investigation?

The most common reason for persistent dysfunction, pain and swelling, post- inversion injury is inadequate rehabilita- tion either by the therapist or due to lack of compliance by the subject.

Check for the site and location of pain, clicking and joint swelling. The ankle will need to be reassessed physically and then a long list of differential diagnoses will need to be considered.

Ankle instability Mechanical instability occurs when there is ligamentous laxity beyond the normal physiological range and this is identified either by clinical examination, eg. anteri- or drawer test, or radiographically.

On

The significance of hearing a snap or the degree of bruising does not seem to be of great diagnostic sig- nificance.

28 SportEX

radiographic testing this is likely to be indicated by greater than 10mm anterior translation or greater than 3mm in side to side difference between anterior draw of the ankles.

If a full and appropriate rehabilitation programme, accompanied by ankle bracing or taping where appropriate, does not resolve the symptoms of functional insta- bility then surgery may be considered in those patients having recurrent episodes and chronic instability.

An anatomical

repair is probably the favoured procedure in most cases.

Other possible injuries Where injuries other than to the ligament complex are suspected it is appropriate to initiate further investigation.

It is impor-

tant to note that plain film radiology, par- ticularly performed in the acute state, might fail to reveal certain fractures partic- ularly if special views are not requested.

A review examination may indicate specif- ic plain film follow up particularly, for example, if the localising tenderness relates to the base of the 5th metatarsal. However, further investigation by triple phase bone scan or magnetic resonance imaging (MRI) would be the next investi- gation of choice depending upon finance and availability of service.

A triple phase bone scan will highlight any areas on the delayed film where bony injury has occurred so that further inves- tigation can be made. There may also be increased activity on the soft-tissue phase but no increased activity on the delayed phase, which would exclude a bony injury. It can also give useful physiological infor- mation that may indicate reflex sympa- thetic dystrophy (or complex regional pain syndrome) which can occur after injury to the ankle. The MRI scan will provide more precise anatomical detail and the STIR sequence will highlight bone bruising, fracture and soft-tissue inflammation.

TIP

TIP

TIP