Author: By Steve “The Footman” Manning Founder of intraini
Shin splints are a generic term that in most runners’ eyes can cover any cause of pain in the lower leg. Sports medicine practitioners have needed to develop more specific terms to differentiate conditions that exist in the leg. The new terms try to reflect the tissues affected and their different causes. Accurate diagnosis is vital to successful treatment as different treatments will work for different conditions.
Medial tibial stress syndrome
The most common cause of shin pain is Medial Tibial stress syndrome. This pain hurts along the inside of the shin most commonly in the lower half and isolated to the medial border of the shin bone, the tibia. It is an inflammation of the tibial skin, called the periosteum, where the fascia of the leg attaches. The fascia is the stiff layer of tissue that holds all the muscles in place. Little tears occur along this attachment causing inflammation and pain.
The pain can sometimes hurt after waking or rest but most commonly hurts at the beginning of a run before warming up. When bad it can begin to hurt again at the end of a run and will hurt a lot afterwards.
Treatment involves a direct icing technique for a few days with the addition of a gentle distraction massage technique after that time. Screening for any underlying biomechanical causes may be necessary if continued running is to not reaggravate the injury. Extended rest is not recommended as the scar tissue will become more entrenched and harder to resolve in the long run.
Prognosis is generally quite good with a significant (greater than 50%) reduction of pain within a week and complete resolution within a month.
Medial tibial stress syndrome that goes untreated may lead to more severe injuries to the bone like bone stress or stress fractures. Stress fractures are most commonly found on the medial border of the tibia but may also occur on the front (anterior) border. It is often overtraining that occurred more than a month before onset that was the cause of the injury.
Pain usually occurs at the start of a run and gets worse without going away. It can ache afterwards and sometimes the pain will wake you at night. Pain is usually localised to a spot on the bone and may hurt on both borders and the shaft. Normal x-rays may pick up a stress fracture after 3-4 weeks but an MRI or bone scan are the only definitive exams.
Unfortunately, bone injuries are one of the few problems that require complete rest from activity. If it is bone stress than after a week there will be significant improvement in point tenderness while a stress fracture will take at least three weeks. With bone stress you can return to running when the pain is gone but stress fractures need 6 to 8 weeks of no running. Once the stress fracture has healed adequately there is less chance of recurrence in the same location.
A compartment syndrome can be defined as the increase in pressure within the limited anatomical space of a fascial compartment which compromises the circulation and function of the tissues within that space. If compartment volume is limited or decreased due to tight or thickened fascia then compartment pressures can increase upon normal muscle swelling during exercise. The anterior compartment muscles are most commonly affected in running.
Generally, there is no pain at rest or at the start of a run. Pain comes on at a certain distance of each run and is too severe to continue. The muscle feels tight and may be firm to the touch. Within a few minutes of stopping the pain has gone completely. If the anterior compartment is affected, then the foot may slap excessively. This is because the purpose of the anterior compartment muscles is to control ankle plantarflexion as they contract and lengthen to lower the forefoot to the ground.
Non-surgical treatment includes changing biomechanics through form modification, change in footwear or orthotics. Avoiding hills or rough surfaces may help as will a reduction of training below the threshold distance of onset of symptoms. Icing and Myofascial release massage techniques can help to release the adhesions between fascia and muscle that may be causing the compartment syndrome.
While immediate improvement can occur, complete resolution can take a very long time. In some cases, surgical intervention is the only successful treatment.
Nerve and vascular entrapments
Some rarer forms of shin pain may mimic the more common causes. Entrapment of the popliteal artery has the same symptoms as compartment syndromes but the onset seems to be more related to intensity of activity rather than duration. Neural entrapments can feel like stress fractures but have less consistent symptoms.
Arterial entrapment will give a lack of pulses at onset which does not occur with chronic exercise induced compartment syndromes. The symptoms of neural entrapment can be reproduced by palpation or percussion of the affected nerve.
Physiotherapy is the best initial treatment however surgery may be required.
Muscle and tendon strains
The posterial tibialis muscle is the most commonly strained in the shin. This muscle acts to control pronation in a similar way that the anterior compartment muscles control ankle motion. The peroneal muscles on the outside of leg control supination to prevent ankle inversion sprains and may also be strained. Pain is usually related to activity and may last for a long time after a run. Pain may occur during other activities of daily living.
Damage may just be normal delayed onset muscle soreness (DOMS) caused by unaccustomed activity or it may be more severe rupture of muscle or tendon. More commonly there was a traumatic event that occurred to cause the injury.
Treatment requires rest and icing for 72 hours. Massage, stretching or heat during this time will make the injury significantly worse. After the 72 hours then a gradual return to activity with massage, stretching and continued icing should see most strains resolve within a week. If the tendon was damaged, or if it was a chronic strain, then much a longer rehab period will be needed.
From these brief descriptions of some of the more common injuries you can see how incorrect diagnosis or treatment can result in a delayed return to running and even worse problems in some situations.