Lower Leg Pain.
Exertional lower leg pain is a commonly diagnosed overuse injury in recreational runner and in the military with an incidence of 27-33% of all lower leg pain presentations. Typically, runners will present with increasing pain on exercise, which is described as ‘tightness’, or ‘constricting pain’. Symptoms can increase with up-hill running or by increasing running speed with a fixed cadence. Symptoms tend to worsen to a point when you are no longer able to run. The pain and symptoms are eased by rest and occasionally can present with short term numbness or weakness or foot slapping, however these usually settle quickly. Classically you are pain free when not exercising. The underlying pathophysiology was thought to be decreased blood flow to the muscle compartment, and termed chronic exertional compartment syndrome (CECS) due to the covering of the muscle – the fascia being too tight or muscle getting too big but to date no evidence of reduced blood flow, or muscle damage due to this has been seen.
There are many causes of shin pain and calf pain, and making the diagnosis is often a complicated task. In my research work to date I have focussed on debunking many of the myths around the diagnosis of chronic exertional compartment syndrome (CECS). CECS was though to result from elevated pressure in the muscle compartments of the legs , however the diagnosis is in doubt as the pressures reached do not stop blood circulating to the muscle, and so the pain seems to not come from pressure. The most common cause of shin or calf pain I see is related to strength capacity. You are asking the lower leg to do more work than it is conditioned to do from perhaps an increase in miles, a new shoe ( particularly the new carbon midsoles- which allow you to do more ankle work, change of training partners or clubs or you are coming back to running after a break.
Recent work on running technique and kinematic and kinetic changes of gait may provide the underlying mechanism behind the propagation of muscle overload. Reduction in the stride length, ground contact time, vertical oscillation and lower extremity angle all contribute to improved running economy, reduced ground reaction force and movement efficiency
Our research has led us to believe that chronic exertional compartment syndrome is a mechanical muscular overload rather than a pathological process and suggest it be considered Biomechanical Overload Syndrome.
We have recently published on our successful treatment of these patients:
We use our SSCRunLab to test strength, power and the sequence of use in ankle, knee, hip and torso and start a focussed program you do yourself in the gym, on the road or track.
There are other causes, and the importance in making a diagnosis is vital, I broadly group these other diagnoses into the “Power supply”, “Blood supply”, “Muscle enzyme” or “bone stress changes”. The nerve supply from the back can be irritated by facet joint osteoarthritis, or a bulging lumbar disc, and a lumbar MRI scan can help us rule these out. More distally, the power supply as it passes around the proximal tibiofibular joint can cause irritation of the common peroneal nerve, more often this causes some weakness in dorsiflexion, but can be ruled out using nerve conduction studies. case for longer disk or modestly around that figure in the case of common perineal nerve.
With respect to the blood supply, either again this can be proximal at the femoral artery, or distally in popliteal artery entrapment syndrome. Here, duplex arteriogram and measurement of ABPIs can rule out the diagnosis. Muscle causes can include compartment syndrome , either post trauma, or in eosinophilic fasciitis, whereto compartment is thickened, and where intra compartmental pressure measurement can be performed, and rarer metabolic causes where muscle biposy is needed. We cannot rule out bony causes such as periostitis or stress fracture must not be missed