There are four main causes of lower leg pain in runners. This update offers guidance on how to manage each of them.
Therapy Update
Running pains
RUNNING is a popular pastime in Australia that is encouraged by many organisations as being beneficial for one’ s health.
Like all pursuits in life, there is a risk – reward ratio. Injury to the lower limb is the biggest risk, with university athletes having injury rates between 25-65 % and soldiers similarly 20-50 %. 1
As health practitioners, we need to be aware of, and not miss, these common injuries.
Popliteal artery entrapment syndrome( PAES) This is a well-described syndrome that is probably an underdiagnosed cause of exertional leg pain.
There are two types of entrapment: anatomical and functional. Anatomical entrapment involves a clear anatomical lesion causing arterial occlusion, usually in the older population, and requires surgical intervention.
The more common functional syndrome occurs because of overcrowding of the popliteal fossa: the medial head of the gastrocnemius compresses the popliteal artery between it and the lateral condyle, plantaris or lateral head of gastrocnemius.
Patients present with exercise-induced calf pain, bilateral in around onethird of cases. Pulses are usually palpable and ankle
brachial index is normal.
Examination post-exercise may be more rewarding with decreased peripheral pulses and a popliteal bruit.
Investigation is usually by Doppler ultrasound, but is limited due to a high falsepositive rate. MRI angiography in association with provocative manoeuvres( passive dorsiflexion or active plantar flexion of the ankle) may provide extra information.
Management Conservative management involves reviewing training loads, massage and strengthening. Failure rates for conservative treatment are high.
Concerns regarding endothelial damage to the popliteal artery with prolonged entrapment means surgical intervention is often recommended. This usually involves releasing the entrapment of the popliteal artery by the medial head of the gastrocnemius and usually is successful in the short term. Long-term studies have not been performed.
Complications include infection and ongoing
SPORTS MEDICINE
There are four main causes of lower leg pain in runners. This update offers guidance on how to manage each of them.
DR SCOTT MASTERS
symptoms of entrapment.
While functional PAES responds poorly to conservative treatments, surgical management carries risk of complications and poor outcomes.
Botulinum toxin type A( BTX-A) is showing promise, with few side effects and a reasonable chance of a good outcome.
The treatment involves injecting 50 units of BTX-A into two sites under ultrasound guidance. Usually this involves a medial approach to the medial head of the gastrocnemius and lateral approach to the plantaris muscle.
Patients need to rest for the remainder of the day and must not be involved in any high-intensity training for the next four weeks. 2 Top-up injections may be needed every six months.
About 60 % of patients will obtain a substantial improvement in their symptoms, with complication rates being very low and mostly mild( calf ache).
BTX-A works by direct muscle paralysis and eventual atrophy. It is also possible that there may be some effect on relaxing popliteal artery smooth muscle. Cost may be an issue.
Chronic exertional compartment syndrome The exact cause of pain in compartment syndrome has not been conclusively elucidated and the original theory of ischaemia has not been substantiated. Further research is needed, but we do know that it is a relatively common cause of exerciseinduced leg pain.
The anterior and lateral compartments are commonly involved, as is the deep posterior compartment.
The cardinal symptom that differentiates this condition is the predictability pain onset at certain levels of exertion. It usually goes away quickly with rest, but as it progresses, it comes on with less activity.
Examination should aim to rule out medial tibial stress syndrome or stress fractures; search for tenderness and check leg pulses for signs of arterial insufficiency. There may be muscle herniation through the fascia.
Diagnosis is confirmed through intracompartmental pressure-testing. The patient’ s pain must be predictable with exercise for this test to be contemplated. It is usually performed as a prelude to surgical intervention.
Management Management usually starts with a trial of conservative therapy. Biomechanical assessment of running style and load, manual therapies such as deep tissue massage, dry needling, prolotherapy and BTX-A injections have all been used with some success.
If conservative measures fail, which is not uncommon, surgery can be considered if compartment pressure testing is positive. Anterior and lateral compartment procedures can usually be performed with percutaneous endoscopically assisted releases and minimal incisions. Deep posterior compartment surgery may require fairly extensive release, but minimal surgery is usually attempted first to minimise morbidity.
Complications of surgery vary between 11 % and 16 %, and include superficial peroneal nerve damage, haematoma, DVT, infection, complex regional pain syndrome and wound dehiscence.
Recurrence rates may be as high as 40 % with surgery, the deep posterior compartment having the poorer prognosis. Anterior and lateral compartments have a 80-90 % success rate. 3
Medial tibial stress syndrome( MTSS) For people who run, this is one of the most common injuries, with an incidence of 15-20 %. 4 A recent review of the literature revealed the primary risk factors were:
• increased BMI;
• increased navicular drop( measure of arch height and pronation);
• increased plantar flexion range of motion; and
• increased hip external rotation. 1 Interestingly, quadriceps angle and ankle dorsiflexion were clearly not risk factors for MTSS.
The old periostitis pathophysiology causation theory has gone and current evidence supports a bony overload injury theory.
This suggests that microdamage during tibial loading, coupled with inadequate recovery and repair time, leads to local tibia osteopaenia. Palpation of the junction of the soft tissue and posteromedial aspect of the tibia reproduces the pain patients feel while exercising. Focal tenderness should alert the practitioner to the possibility of a stress fracture. cont’ d next page
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