Muscle Strain – Torn Muscle – Muscle Tear
What is a muscle strain?
A muscle strain is a torn muscle. This is contrasted with a sprain which refers to an injury to a ligament. Muscle strains can range in severity from very mild (Grade 1) where only a few muscle fibers are torn, to severe (Grade 3) where the entire muscle may be torn (Figure 1).
How does a muscle strain occur?
When the internal forces generated by a muscle contraction are stronger than the muscle can handle, tearing of the muscle fibers will occur. The strongest muscle forces occur when the muscle is both contracting and lengthening at the same time. This is called an eccentric contraction, and it is common in many movements. Muscle that are stiff from a lack of warm-up or aging are more likely to tear. This combine with a maximal athletic effort predisposes to a muscle tear. A muscle strain differs from a contusion in that the injury occurs from internal forces as opposed to external forces from a direct blow which cause contusions. Both injuries can lead to bleeding in the soft tissue, which can appear as bruising.
What are the symptoms of a torn muscle?
Pain and dysfunction of the injured muscle following an acute episode is the main symptom of a muscle strain. The injured muscle will often be painful to touch. Movements that use the affected muscle will be difficult or impossible, depending upon the extent of the injury. In the days after the injury bruising may appear under the skin.
Which muscle groups are commonly strained?
Any muscle group can suffer a tear if the forces are great enough. However, some muscles are more commonly injured. Calf muscle tears, hamstring tears, and quadriceps tears are all relatively common injuries in athletes performing explosive activities.
Imaging Studies
Muscle strains will usually not be diagnosed on plain x-rays. However, some muscle and tendon injuries are associated with a pulling off of a fragment of bone (an avulsion) where the muscle tendon unit attaches. This avulsion of bone may be seen on x-ray.
An MRI or an ultrasound may give a more detailed assessment of the extent of the muscle injury. However, for many mild muscle strains these imaging test will not change the management and therefore may not be necessary. For more severe muscle injuries an MRI can be very helpful with respect to prognosis.
Prognosis Following a Muscle Strain
The expected recovery time and ultimate function following a muscle strain depends upon the severity of the injury –and which muscle was injured. Unlike fractures of bone which heal with bone, muscle strains and ligament sprains heal with scar tissue. There is always some permanent change in the muscle tissue following a muscle strain. For mild strains were only a few of the muscle fibers are torn and local bleeding is minimal the muscle will heal adequately provided that appropriate rehabilitation is performed. The patient should make a complete recovery. For more severe strains the recovery will be longer, and there may be residual weakness in the affected muscle. In some severe muscle strains, the healed scar tissue can create some ongoing discomfort in the injured muscle.
Treatment of Muscle Strains
Most muscle strains can be treated conservatively. An initial period of rest and relative immobilization is necessary to allow the injured muscle to start the healing process. This can range from a few days to a few weeks, depending upon the severity of the muscle injury. As soon as it is feasible, gentle motion of the injured muscle can be started in order to minimize soft-tissue scarring and adhesions. However, more aggressive strengthening of the healing muscle should be delayed until the injury to the muscle has healed with adequate strength. Formal rehabilitation with guidance from a physical therapist is often necessary, particularly for moderate to severe muscle strains. A coordinated rehabilitation program will help to minimize muscle scarring and work to regain full muscle strength in a graduated manner.
Surgical Treatment of Muscle Tears
Most muscle strains will not require surgery. However, if there is a complete disruption of the muscle or the muscle-tendon unit has detached from the bone (ex. a hamstring avulsion) surgery may be needed to repair the disrupted muscle. In addition, some patients will develop chronic painful scarring following a muscle strain. If symptoms are bad enough and have not responded to physical therapy surgery to clean up the scar tissue may need to be considered at a later date.
July 15th, 2024