LOWER LIMB INJURIES

interested parties in sports medicine. They defined ‘shin splints’ as ‘pain and discomfort in the leg from repetitive run- ning on hard surfaces or forcible, exces- sive use of foot flexors; diagnosis should be limited to musculotendinous inflamma- tions, excluding fracture or ischaemic dis- order’.

There was mixed response to this

definition but in the main it was widely criticised.

There now exists a broad agreement that most exercise induced leg pain (EILP) will fall into one of the following categories:

(1) Pain of bony origin eg. focal stress fracture and diffuse micro-fracture of stress reaction (2) Pain of osteofascial origin usually along the medial border of the tibia eg. periostitis and commonly referred to as medial tibial stress syndrome (MTSS) (3) Pain of muscular origin eg. delayed muscle soreness after eccentric activity, cramp, and acute and chronic compart- ment syndrome (ACS and CCS) (4) Pain due to compression of a nerve eg. compression of superficial peroneal and tibialis posterior nerve (5) Spinal pain

In addition, there are other conditions which may mimic and present with similar symptomatology and should be included

Diagnosis In subjects presenting with EILP, diag- nosis is pivotal. Blind management under the umbrella term ‘shin splints’ often leads to delay in appropriate management and early return to sport- ing activity.

Diagnosis in the main is

based on history, examination and appropriate investigations.

History A detailed history is of utmost impor- tance as the clinical examination is often normal. ● Sudden onset of pain is suggestive of stress fracture ● Gradual onset is suggestive of CCS or/and MTSS ● Duration of pain after exercise is very important - pain that only lasts a few minutes is indicative of CCS, pain that persists for hour/s is indicative of MTSS

28 SportEX

in the differential diagnosis (see page 32).

Differential diagnosis 1. CHRONIC COMPARTMENT SYN- DROME (CCS) Definition: A condition in which increased pressure within a closed anatomical space compromises circulation and the tissues within that space. Another definition states ‘a reversible rise in tissue pressure to abnormal levels brought on by exertion and relieved by rest.’

Cause: Primarily due to relative inadequa- cy of musculo-fascial compartment size that is further compounded by increase in muscle volume with activity. It is estimat- ed that skeletal muscles increase in vol- ume during exercise by as much as 20%.

Presentation: The patient typically pre- sents with pain on exercise which is relieved by rest. The condition is also known as ‘recurrent compartmental syn- drome’,

‘exercise induced’, ‘exertional’ compartment syndrome.

‘subacute’ or The

term is more commonly referred to as ‘chronic compartment syndrome’.

Anatomy: The leg is essentially divided into four main compartments (Fig.1) which are separated by fascia, bone and interosseous ligaments. They run cylindri-

pain that is associated with numbness and paraesthesia is indicative of nerve entrapment ● History of diabetes mellitus and back problems may be relevant

Examination Examination is often normal but is impor- tant in locating tenderness over the anatomical site.

tibia

extensors and invertors

posterior flexor compartment

superficial flexors

fibular evertors

Figure 1: Cross section of the compartments of the lower leg

cally down the leg and consist of exten- sors and invertors (anterior), evertors (lateral), and flexors (deep and superficial posterior).

Pathophysiology: All theories concerning the pathophysiology of CCS propose an increase in tissue pressure to a critical level which results in a compromise of perfusion. This may be due to either excessive swelling of the muscles or insuf- ficient compliance of the surrounding fas- cia. A compartment syndrome occurs when the pressure in the compartment affected rises during exercise to a level which will interrupt the blood supply to the muscles thus resulting in pain.

The approximate pressure for this to occur is 40mm Hg in

artery entrapment syndrome (PAES) (5) A positive Tinel sign is indicative of either superficial peroneal entrapment or tarsal tunnel (6) Spinal stenosis - a full back exami- nation is a must to exclude this diagno- sis

This may aid in pre-

sumptive diagnosis and direct the clini- cian in requesting specific investigation. (1) Medial tibial tenderness may suggest MTSS (2) Presence of fascial herniae, mostly found in the anterior compartment may suggest CCS (3) Point specific tenderness over the bone, mainly tibia, may suggest stress fracture (4) Checking peripheral pulses for periph- eral ischaemia of diabetes and popliteal

Investigations ● Urine test for diabetes ● Plain radiographs of tibia and fibula ● Triple phase isotope bone scan ● Magnetic resonance imaging (MRI) scan ● Electromyography (EMG) ● Doppler blood flow studies ● Dynamic intra-compartment pressure studies (DICPS) ● Plain radiographs of the spine, and if indicated computerised tomography (CT) scan or MRI scan