A 27 year old recreational runner training for the Paris marathon presents a 4 month history of exercise induced lower leg pain exacerbated by running for 45 minutes and eased with 5/10 minutes of rest.  His running style is characterized by heavy impact, overpronation, strike on midfoot, and poor pelvic control during swing.  No localized tenderness on palpation.  Walking and climbing do not reproduce pain.  The patient presents tightness at the quadriceps, ITB and iliopsoas muscles.  All other objective findings are unremarkable.
Risk Factors and sports specific aspects
Pain in the lower leg caused by exercise is a common presentation amongst athletes involved in weight-bearing activities, and specifically running.  Exercise induced leg pain (EILP) has many aetiologies and the health professional must strive to clearly assess the clinical presentation in order to administer an effective treatment.  According to Padhiar (1), EILP can be categorized as follows:
  • Pain of bony origin: focal stress fracture and diffuse micro-fracture of stress reaction;
  • Pain of osseofascial origin usually along the medial border of the tibia (Medial tibial stress syndrome, MTSS);
  • Pain of muscular origin: exertional compartment syndrome (acute and chronic ECS);
  • Pain due to a nerve compression (superficial peroneal and tibialis posterior);
  • Pain of ridiculer origin due to the compression of a nerve at the spine or pelvis;
  • Pain due to the temporary compromise to the vascular supply to the region (Popteal artery entrapment syndrome)
MTSS and ECS are the most common entities with studies reporting incidences from 13% to 42% and 27% to 33% respectively (2).  Both conditions are exercise related and are exacerbated by activity and often deteriorate with sudden changes in training regime.
Examination Findings
  •  Absence of swelling or localized fascial hernia
  • Hypertrophy of tibialis anterior, right more than left
  • Pes Planus with both medial arches fully collapsed
ROM/resisted tests
  • Full ankle and knee ROM
  • Resisted tests for ankle dorsi/plantar flexion, inversion/eversion, supination/pronation were all unremarkable
  • Knee resisted flexion/extension were negative
  • No localized specific tenderness over the tibial border
  • Peripheral pulses are unremarkable
  • Tinsel sign is negative
Analysis of running style
This test was performed on a treadmill.  A warm-up period of 3 minutes was initially performed at a velocity of 6km/hr which was gradually increased every 2 minutes to a max speed of 13.5 km/hr.  This was the patient’s velocity during her weekly training at the gym.  The patient was wearing her usual running trainers.  Her running style was characterized by:
  • Heavy impact on contact with the ground
  • Striking phase on the mid-foot with immediate over-pronation
  • Reduced swing phase with limited hip flexion and knee flexion/extension
  • Pelvic movement was characterized by an immediate shift on impact with poor gluteal activation
  • Limited arm swing and trunk in a very upright position
  • In the last 10 minutes of running, the patient’s performance started deteriorating and              was characterized by:
  • Swing phase was further reduced and presented increase hip internal rotation with poor pelvic control
  • Trunk flexion and arm swing increased
  • Strike during the stance phase moved to mid/forefoot with reduction in power during the take-off phase.
Other tests
Thomas’s test reproduced increased tightness at the level of the quadriceps and ITB.  The modified version reproduced tightness at the iliopsoas level.
SLR was 50° on the right side and 45° on the left.
Chronic exertional compartment syndrome        70%
Stress Fracture                                                    25%
Medial tibial stress syndrome                                 5%
Hypotheses justification
Chronic exertional compartment syndrome
The patient’s presentation of exercise induced bilateral leg pain which is relieved by few minutes of rest and no localized tenderness on palpation is a strong indication of exercise related compartment syndrome.  Exertional compartment syndrome (ECS) is a condition of pain in the leg when the normal expansion of the muscle from exercise demands results in increased pressure in an unyielding osseofascial compartment (2).  Acute ECS is typically due to a trauma or ischemic event and is generally more severe in nature and require emergency surgical decompression.  Since it was described in 1942, acute ECS is now a widely documented condition (1).  Chronic ECS (CECS) of the lower leg is instead induced by exercise that impairs neuromuscular function within the involved compartment and is characterized by an onset of pain after a specific amount of exercise (3).   In CECS, a reversible rise in tissue pressure to abnormal levels brought on by exertion and relieved by rest has the potential to compromise circulation and the tissues within the compartmental space (4).  In the presence of appropriate clinical findings, Paedowitz et al. (5) consider one or more of the following intramuscular pressure criteria to be diagnostic of chronic compartment syndrome of the leg:
  • a pre-exercise pressure greater than or equal to 15 mm Hg;
  • a 1 minute post-exercise pressure of greater than or equal to 30 mm Hg;
  • a 5 minute post-exercise pressure greater than or equal to 20 mm Hg.
CECS typically occurs amongst young active individuals and is reported to be bilateral with incidences between 60% (6) and 82% (7).  Patients will often complain of an aching pain during a specific phase of their training regime which worsens as the exercise continues and will consequently prevent continuation of the activity and is relieved by rest.
Figure: Tibial compartment fasciotomy: Previous compartment  (tibialis anterior, extensordigitorum longus hallucis longus Extensior) Lateral compartment (peroneus longus,peroneus brevis) Posterior compartment (Tibialis posterior, flexor digitorum, Flexorhallucis, Plantaris, Soleus, Gastrocnemius).
Stress fractures
Stress fractures are a common type of overuse injury within the athletic population.  The tibia is the most frequent site to suffer a stress fracture with an incidence between 25% and 46% (2).  Most stress fractures of the tibia occur in the proximal metaphysics, with a smaller amount on the lower third.  However, the site of the fracture is closely related to the type of sport performed: in running, for example, injuries are largely localized in the midshaft or distal mid third of the tibia (8).  Running is the type of activity more often associated with tibial stress fractures due to the variation in loading applied, possibly causing up to a 6-fold in tibial strain when compared to walking.   According to Beck (11), subtle alterations in tibial loading may lead to bone pathology if skeletal adaptations fail to keep pace with loading demands.
Typically, patients will present with a history of exertional pain of insidious onset localized to the area affected which is usually worse after exercise often following a change in training regime.  Clinical examination often present limited signs: localized point tenderness and swelling may be present.  In the case of this patient, symptoms follow the clinical history of increased training routine, exercise induced and poor gait biomechanics associated with the development of stress fracture.  However, bilateral symptoms are not frequent and palpable tenderness was absent.
Medial tibial stress syndrome 
MTSS is a common injury in runners and typically occur after a period of prolonged activity or during the start of a training season after a period of relative rest (8).  The patient presenting MTSS will complain of lower limb pain either during or after exercise, with pain persisting for a prolonged period (hours to days) after cessation of the activity (9).  Detmer (7) considered MTSS as a continuum from stress reaction to stress fracture.  The classification of MTSS was made into 3 subdivisions according to existing symptomatology and imaging results:
  • Type I (tibial micro fracture, bone stress reaction or cortical fracture);
  • Type II (periostalgia from chronic avulsion of the periosteum at the periosteal-fascial junction);
  • Type III (chronic compartment syndrome).
The most relevant feature during examination in MTSS is the inner tibial border tenderness.    Classically, the pain is always located in the lower 1/3 leg and swelling may also be present.  Considering the patient does not present localized tenderness on examination and pain eases after few minutes of rest, the diagnosis of MTSS appears to have a poor confidence level.
Further investigations
In order to confirm the diagnosis of CECS and differentiate it from other lower leg pathologies, the author would recommend a series of medical tests, which include:
  • Plain radiographs are relatively inexpensive and accessible.  They are likely to produce negative findings in CECS and MTSS, but can rule out late stage stress fracture.
  • Triple phase bone scan is the preferred investigation type to determine MTSS and stress fracture.  In stress fractures, the typical appearance is of a focal area of increased signal.  This must be differentiated from the findings with MTSS which are characterised by a diffuse area of positive uptake along the posteromedial border of the tibia (2)
  • Proton-density MRI scans have shown specific changes after exercise in CECS and these are believed to be due to increased extracellular water content (13).  The use of this investigation is currently still limited mainly to research protocols.
  • The hallmark diagnostic tool for CECS is compartment pressure testing, which can be performed using four different techniques: injection, infusion, non infusion and micro-tip transducer techniques (14).  This investigation is highly invasive, requires specific equipment and trained staff.  However, it offers valid and reliable measurements of compartmental pressure during active exercise.
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