3. TIBIAL STRESS FRACTURE (TSF) There is considerable knowledge of the nature of tibial stress injuries and most recent studies suggest they are a result of the repetitive tibial strain imposed by loading during monotonous weight bear- ing activity.
The aetiology of TSF is based on the evi- dence that micro-stress fractures occur at the site of maximum shear strain as a result of repeated tibial bending. There is further evidence to suggest that micro- fractures are likely to occur as a conse- quence of reduced tissue resistance to strain following the development of re- modelling related bone porosity.
Clinical symptoms: Pain in the leg occurs during and after exercise. The pain will persist even at rest and often the patient will limp with pain persisting for days and weeks after cessation of physical activity. The onset of pain is often acute with recall of a specific event that led to the pain. Sometimes when questioned they will report training or playing on a hard surface. In some cases they may experi- ence ‘crescendo’ pain especially at night.
Examination : There is point specific ten- derness over the site of fracture.
Investigations ● Plain radiographs - will reveal the site of fracture by indicating the presence of callus.
This may be absent if x-rays are
taken too early ● Isotope bone scan - will show focal uptake at the site of fracture (Fig.4)
Treatment ● Rest - 6-9 weeks until the pain has totally subsided ● In florid cases where the patient is in considerable pain and demonstrates crescendo pain at the site of fracture with nocturnal symptoms, immobilise in walk- ing plaster of paris/Scotch cast
4. NERVE ENTRAPMENT The superficial peroneal nerve as it exits through the fascia at the junction of the lower and middle third of the lateral leg is the nerve that is most commonly affected (Fig.5).
Occasionally the posterior tibial
nerve may be trapped in the tarsal tunnel inferior to the medial malleolus.
Clinical symptoms: Pain and paraesthe- sia, sometimes distal numbness are the pivotal symptoms.
Superficial peroneal nerve
Often worse during
exercise but can also be present at rest and at night. A trapped superficial per- oneal nerve exhibits paraesthesia on the dorsal aspect of the foot while the poste- rior tibial nerve exhibits paraesthesia on the heel and plantar aspect of the foot.
Examination: The nerve will be irritable at the site of entrapment and if tapped, will give a positive Tinel’s sign (repro- duced paraesthesia). This can be further confirmed by either injecting the site with a local anaesthetic or performing nerve conduction/EMG studies.
Investigations ● Nerve conduction / EMG studies
Treatment ● Local anaesthetic injection mixed with steroid ● Surgical release of the nerve
5. POPLITEAL ARTERY ENTRAPMENT SYNDROME This condition is extremely rare with vary- ing underlying pathology.
Pathogenesis: The popliteal artery becomes occluded during exercise either by the abnormal anatomy of the gastroc- nemius muscle or a thick fibrous band.
Figure 4: Focal uptake at fracture site (isotope bone scan)
Clinical symptoms: The symptoms are identical to CCS with the pain occurring during exercise and relieved by variable periods of rest.
Examination: Examination is most often normal but should be suspected if the peripheral pulse (tibialis posterior found behind the medial malleolus) disappears when the ankle joint is acutely plan- tarflexed.
Investigations ● Doppler ultrasound ● Arteriogram
Treatment: Surgery to stop occlusion of the artery.
6. SPINAL COMPONENTS The spine can cause exercise-related leg pain or be a component of its presenta- tion. This may be direct somatic referral from lumbar joint, disc, or ligamentous structures, typically in a dermatomal pat- tern. It may alternatively be caused by spinal or intervertebral foramen stenosis. Restriction of nerve movement due to irri- tation by, or adhesion to, any of the closely related structures along its length can cause peripheral or central symptoms typically within the area supplied by a particular cutaneous nerve.