DIFFICULT ANKLE

capsule as is more commonly seen in soc- cer players and runners.

Investigation: There may be palpable thickened synovium and tenderness along the anterior talo-crural joint line. Dorsiflexion may be limited by pain and/or bony impingement. These lesions are best viewed radiographically in a weight bearing lateral ‘lunge’.

Management: They may respond to phys- ical therapy and injection with cortico- steroid but more commonly surgical treat- ment is required.

iii) Posterior impingement Cause: Posterior impingement can occur secondary to ankle plantar flexion/inver- sion injuries particularly with ankle insta- bility. This is most commonly seen in bal- let dancers, gymnasts, cricketers and foot- ballers.

Investigation: A positive anterior drawer allows the talus to move forward and the posterior aspect of the tibia impinges on an enlarged posterior tubercle of the talus (Steida’s process) (Fig.4). In about 10% of the population there will be an os trigonum (ossicle behind the posterior talus) (Fig.4) which usually has a fibrous attachment which can be disrupted by the injury. The diagnosis is suggested by pain on plantar flexion activity, particularly going en-pointe in dancers.

Forcible

plantar flexion will reproduce the discom- fort.

There may be a definite fracture as

outlined previously or simply some increased uptake on bone scan or bone oedema on MRI.

Management: Posterior impingement without fracture can be treated by corti- costeroid injection.

The use of local

anaesthetic will confirm the diagnosis by the abolition of pain on impingement testing.

9. NERVE INJURIES Peroneal nerve injury can occur as a result of an inversion injury and may not be recognised immediately.

This should be

considered particularly when the peroneal muscles are weak and rehabilitation is dif- ficult. Studies have demonstrated elec- tromyographical confirmation of denerva- tion in both the peroneal and tibial nerves following severe ankle sprains.

On rare occasions it has resulted in a permanent 34 SportEX

Investigation: Changes in blood flow may occur resulting in palpable discrepan- cy in skin temperature or sweating but these findings are not essential for diag- nosis nor are the classical appearance of a truly established RSD.

tope bone scan will help to confirm the diagnosis with a marked reduction in blood pool and delayed phase.

Management: If suspected these lesions respond well to Guanethidine nerve block and should be treated early and aggres- sively before longterm pain and dysfunc- tion sets in.

11 ANTERIOR INFERIOR TIBIO-FIBULAR LIGAMENT INJURIES These injuries are less common in the typ- ical inversion injury and tend to occur with more severe injuries and may accom- pany malleolar fractures. The pain may be

Focal area of

markedly increased uptake

Evaluate with CT or MRI

● Osteochondral talar dome

● Avulsion 5th metatarsal

● Lateral talar process

● Anterior calcaneal process

Diagram 2: Interpretation of isotope bone scan adapted from Brukner & Khan (1) Isotope bone scan

Area of moderately increased uptake

No increased uptake on delayed films

Possible increase in soft tissue phase

● Chronic synovitis

● Impingement syndrome

● Late RSD – patchy uptake ● Tarsal coalition

● Acute synovitis

● Impingement syndrome

● Increased RSD – decreased all phases

● Peroneal tendon injury

● Sinus tarsi syndrome

foot drop.

Nerve lesions generally have a

good prognosis but may require some pro- tective splinting or orthoses until recov- ery is complete.

10. REFLEX SYMPATHETIC DYSTROPHY (RSD) (OR COMPLEX REGIONAL PAIN SYNDROME) Presentation: This may occur following injury and there may be pain and tender- ness disproportionate to the apparent injury present.

produced by dorsiflexion and external rotation and tenderness is localised to the ligament area.

These lesions invariably

take longer to rehabilitate and will require a longer period of protection and rehabil- itation.

Injuries to the ankle syndesmosis usually occur with eversion injuries but in delayed recovery they must be suspected because if they go undetected they will progress to early ankle osteoarthritis without surgery.

Changes on iso-

There are many other potential diagnoses to consider and the above list is not exhaustive. However a full history, clini- cal assessment and initiation of appropri- ate investigations should aid the clinician in producing a clear action plan and the successful management of these cases is professionally rewarding.

Dr Nick Webborn is a GP turned full-time sports physician in West Sussex. He is a SportEX advisor and has recently been appointed medical advisor to the National Institute of Sports Medicine.

Recommended reading 1. Brukner & Kahn. ‘Clinical Sports Medicine’ McGraw-Hill 1993 2. Reid D. ‘Sports injury assessment and rehabilitation’ Churchill Livingstone 1992 3. Renstrom P & Konradson L. `Ankle ligament injuries’ Br. J. Sports Med. 1997;31:11-20