Overview of Sprains and Other Soft-Tissue Injuries
In addition to sprains, strains, and tendon injuries, musculoskeletal injuries include
Musculoskeletal injuries are common and vary greatly in mechanism, severity, and treatment. The extremities, spine, and pelvis can all be affected.
Musculoskeletal injuries may occur in isolation or as part of multisystem trauma (see Approach to the Trauma Patient). Most musculoskeletal injuries result from blunt trauma, but penetrating trauma can also damage musculoskeletal structures.
(See also Approach to Sports Injuries.)
Tendon tears can be partial or complete.
With complete tears, the motion produced by the detached muscle is usually lost.
Partial tears can result from a single traumatic event (eg, penetrating trauma) or repeated stress (chronically, causing tendinopathy). Motion is often intact, but partial tears may progress to complete tears, particularly when significant or repetitive force is applied.
Serious complications of sprains, strains, and tendon injuries are unusual but may cause permanent limb dysfunction.
Acute complications (associated injuries) include the following:
Bleeding: Bleeding (eg, bruising, ecchymoses) accompanies all significant soft-tissue injuries.
Vascular injuries: Rarely, what appears to be a severe sprain may be a spontaneously reduced dislocation (eg, of the knee), which may be accompanied by a limb-threatening arterial injury.
Nerve injuries: Nerves may be injured when stretched or damaged by associated injuries such as fractures or dislocations or by blunt blows or crush injuries. When nerves are bruised (called neurapraxia), nerve conduction is blocked, but the nerve is not torn. Neurapraxia causes temporary motor and/or sensory deficits; neurologic function returns completely in about 6 to 8 weeks. When nerves are crushed (called axonotmesis), the axon is injured, but the myelin sheath is not. This injury is more severe than neurapraxia. Depending on the extent of the damage, the nerve can regenerate over weeks to years. Usually, nerves are torn (called neurotmesis) in open injuries. Torn nerves do not heal spontaneously and may have to be repaired surgically.
Compartment syndrome: Rarely, swelling under a cast is severe enough to contribute to compartment syndrome. Tissue pressure increases in a closed fascial space, disrupting the vascular supply and reducing tissue perfusion. Untreated compartment syndrome can lead to rhabdomyolysis, hyperkalemia, and infection. It can also cause contractures, sensory deficits, and paralysis. Compartment syndrome threatens limb viability (possibly requiring amputation) and survival.
Long-term complications include the following:
Instability: Various ligament injuries, particularly 3rd-degree sprains, can lead to joint instability. Instability can be disabling and increases the risk of osteoarthritis.
Stiffness and impaired range of motion: Stiffness is more likely if a joint needs prolonged immobilization. The knee, elbow, and shoulder are particularly prone to posttraumatic stiffness, especially in the elderly.
Osteoarthritis: Injuries that result in joint instability predispose to repeated joint stresses that can damage joint cartilage and result in osteoarthritis.
Diagnosis of sprains, strains, and tendon injuries should include a thorough history and physical examination, which are often sufficient for diagnosis.
In the emergency department, if the mechanism of injury suggests potentially severe or multiple injuries (as in a high-speed motor vehicle crash or fall from a height), patients are first evaluated from head to toe for serious injuries to all organ systems and, if needed, are resuscitated (see Approach to the Trauma Patient).
Patients should be checked for fractures and dislocations as well as ligament, tendon, and muscle injuries; sometimes parts of this evaluation are deferred until fracture is excluded.
The joint above and below the injured joint should also be examined.
History focuses on the
Clinicians should also ask about use of drugs (eg, fluoroquinolones, corticosteroids) that increase the risk of tendon tears.
The mechanism (eg, direction and magnitude of force) may suggest the type of injury. However, many patients do not remember or cannot describe the exact mechanism.
If a patient reports a deformity that has resolved before the patient is medically evaluated, the deformity should be assumed to be a true deformity that spontaneously reduced.
A perceived snap or pop at the time of injury may signal a ligament or tendon injury (or a fracture). Serious ligamentous injuries usually cause immediate pain; pain that begins hours to days after the injury suggests minor injury.
Vascular and neurologic assessment
Inspection for deformity, swelling, ecchymoses, open wounds, and decreased or abnormal motion
Palpation for tenderness, crepitus, and gross defects in bone or tendon
Examination of the joints above and below the injured area
After fracture and dislocation are excluded (clinically or by imaging), stress testing of the affected joints for pain and instability
If muscle spasm and pain limit physical examination (particularly stress testing), examination is sometimes easier after the patient is given a systemic analgesic or local anesthetic. Or the injury can be immobilized until muscle spasm and pain subside, usually for a few days, and then the patient can be reexamined.
Deformity suggests dislocation, subluxation (partial separation of bones in a joint), or fracture.
Swelling commonly indicates a significant musculoskeletal injury but may require several hours to develop. If no swelling occurs within this time, severe ligament disruption is unlikely.
Tenderness accompanies nearly all injuries, and for many patients, palpation anywhere around the injured area causes discomfort. However, a noticeable increase in tenderness in one localized area (point tenderness) suggests a sprain (or fracture). Localized ligamentous tenderness and pain when the joint is stressed are consistent with sprain. With some complete muscle or tendon tears, a defect may be palpable in the affected structure.
Gross joint instability suggests severe ligamentous disruption (or dislocation, which may have spontaneously reduced).
Stress testing is done to evaluate the stability of an injured joint; however, if a fracture is suspected, stress testing is deferred until x-rays exclude fracture. Bedside stress testing involves passively opening the joint in a direction usually perpendicular to the normal range of motion (stressing). Because muscle spasm during acutely painful injuries may mask joint instability, the surrounding muscles are relaxed as much as possible, and examinations are begun gently, then repeated, with slightly more force each time. Findings are compared with those for the opposite, normal side but can be limited by their subjective nature.
Findings can help differentiate between 2nd- and 3rd-degree sprains:
If muscle spasm is severe despite use of analgesia or anesthetic injection, the examination should be repeated a few days later, when the spasm has subsided.
Some partial tendon tears escape initial clinical detection because function appears intact. Any of the following suggests partial tendon tears:
Partial tendon tears may progress to complete tears if patients continue to use the injured part. If the mechanism of injury or examination suggests a partial tendon injury or if the examination is inconclusive, a splint should be applied to limit motion and thus the potential for further injury. Subsequent examination, occasionally supplemented with MRI, may further delineate the extent of injury.
Attention to certain areas during examination can help detect commonly missed injuries (see table Examination for Some Commonly Missed Soft-Tissue Injuries).
Examination for Some Commonly Missed Soft-Tissue Injuries
If physical examination is normal in a joint that patients identify as painful, the cause may be referred pain. For example, patients with a sternoclavicular joint injury may feel pain in their shoulder. Thus, clinicians should always examine the joint above and below the injury.
Not all limb injuries require imaging. Many ankle sprains do not require x-rays during the initial evaluation because the probability of finding a fracture that would require a change in treatment is acceptably low; for ankle sprains, explicit, generally accepted criteria for obtaining x-rays (Ottawa ankle rules) can help limit x-rays to patients that are more likely to have a fracture requiring specific treatment. If imaging is needed, plain x-rays are done first.
Plain x-rays, which show primarily bone (and joint effusion secondary to bleeding or occult fracture), may be done to check for dislocations and fractures; plain x-rays do not show direct evidence of sprains but may show abnormal anatomic relationships that suggest sprains or other soft-tissue injuries. X-rays should include at least 2 views taken in different planes (usually anteroposterior and lateral views).
Additional views (eg, oblique) may be done when
For lateral views of digits, the digit of interest should be separated from the others.
MRI can be done to identify soft-tissue injuries, including ligament, tendon, cartilage, and muscle injuries.
MRI or CT may also be done to check for subtle fractures.
Serious associated problems, if present, are treated first. Hemorrhagic shock is treated immediately. Injuries to arteries are surgically repaired unless they affect only small arteries with good collateral circulation. Severed nerves are surgically repaired; for neuropraxia and axonotmesis, initial treatment is usually observation, supportive measures, and sometimes physical therapy.
Suspected open fractures or dislocations require
Most moderate and severe injuries, particularly grossly unstable ones, are immobilized immediately by splinting (immobilization with a nonrigid or noncircumferential device) to decrease pain and to prevent further injury to soft tissues by unstable injuries.
Pain is treated as soon as possible, typically with opioids.
After initial treatment, soft-tissue injuries are treated symptomatically and are immobilized as indicated.
Many 3rd-degree sprains and tendon tears require surgical repair.
Patients who have soft-tissue injuries, with or without other musculoskeletal injuries, may benefit from PRICE (protection, rest, ice, compression, elevation), although this practice is not supported by strong evidence.
Protection helps prevent further injury. It may involve limiting the use of an injured part, applying a splint or cast, and/or using crutches.
Rest may prevent further injury and speed healing.
Ice and compression may minimize swelling and pain. Ice is enclosed in a plastic bag or towel and applied intermittently during the first 24 to 48 hours (for 15 to 20 minutes, as often as possible). Injuries can be compressed by a splint, an elastic bandage, or, for certain injuries likely to cause severe swelling, a Jones compression dressing. The Jones dressing is 4 layers; layers 1 (the innermost) and 3 are cotton batting, and layers 2 and 4 are elastic bandages.
Elevating the injured limb above the heart for the first 2 days in a position that provides an uninterrupted downward path allows gravity to help drain edema fluid and minimize swelling.
After 48 hours, periodic application of warmth (eg, a heating pad) for 15 to 20 minutes may relieve pain and speed healing.
Immobilization decreases pain and facilitates healing by preventing further injury.
First-degree sprains are immobilized briefly if at all. Early mobilization is best. Mild 2nd-degree sprains are often immobilized with a sling or splint for a few days. Severe 2nd-degree and some 3rd-degree sprains and tendon tears are immobilized for days or weeks, sometimes with a cast. Many 3rd-degree sprains require surgery; usually, immobilization is only adjunctive therapy.
A cast is usually used for injuries that require weeks of immobilization. Rarely, swelling under a cast is severe enough to contribute to compartment syndrome. If clinicians suspect severe swelling under a cast, the cast (and all padding) is cut open from end to end medially and laterally (bivalved).
Patients with casts should be given written instructions, including the following:
Keep the cast dry.
Never put an object inside the cast.
Inspect the cast’s edges and skin around the cast every day, and report any red or sore areas.
Pad any rough edges with soft adhesive tape, cloth, or other soft material to prevent the cast’s edges from injuring the skin.
When resting, position the cast carefully, possibly using a small pillow or pad, to prevent the edge from pinching or digging into the skin.
Elevate the cast whenever possible to control swelling.
Seek medical care immediately if pain persists or the cast feels excessively tight.
Seek medical care immediately if an odor emanates from within the cast or if a fever, which may indicate infection, develops.
Seek care immediately for progressively worsening pain or any new numbness or weakness.
Good hygiene is important.
A splint (see figure Joint immobilization as acute treatment: Some commonly used techniques) can be used to immobilize some stable injuries, including some suspected but unproven fractures, rapidly healing fractures, sprains, and other injuries that require immobilization for several days or less. A splint is noncircumferential; thus, it enables patients to apply ice and to move more than a cast does. Also, it allows for some swelling, so it does not contribute to compartment syndrome. Some injuries that ultimately require casting are immobilized initially with a splint until most of the swelling resolves.
A sling provides some degree of support and limits mobility; it can be useful for injuries that are adversely affected by complete immobilization (eg, for shoulder injuries, which, if completely immobilized, can rapidly lead to adhesive capsulitis [frozen shoulder]).
A swathe (a piece of cloth or a strap) may be used with a sling to prevent the arm from swinging outward, especially at night. The swathe is wrapped around the back and over the injured part.
Prolonged immobilization (> 3 to 4 weeks for young adults) of a joint can cause stiffness, contractures, and muscle atrophy. These complications may develop rapidly and may be permanent, particularly in the elderly. Some rapidly healing injuries are best treated with resumption of active motion within the first few days or weeks; such early mobilization may minimize contractures and muscle atrophy, thus accelerating functional recovery. Physical therapists can advise patients as to what they can do during immobilization to maintain as much function as possible (eg, elbow, wrist, and hand range-of-motion exercises if the shoulder is immobilized).
After immobilization, physical therapists can help patients regain or improve range of motion and muscle strength and can provide exercises to strengthen and stabilize the injured joint and thus help prevent recurrence and long-term impairment.
The elderly are predisposed to musculoskeletal injuries in general because of the following:
For any musculoskeletal injury in the elderly, the goal of treatment is rapid return to activities of daily living.
Immobility (joint immobilization) is more likely to have adverse effects (eg, stiffness, contractures, muscle atrophy) in the elderly.
Early mobilization and physical therapy are essential to recovery of function.
Coexisting disorders (eg, arthritis) can interfere with recovery.
Compartment syndrome and injuries that disrupt arterial supply threaten limb viability and may ultimately threaten life; these problems are very rare with sprains and strains.
Check for fractures and dislocations, and consider spontaneously reduced dislocations, as well as ligament, tendon, and muscle injuries; sometimes part of this evaluation is deferred until fracture is excluded.
Consider referred pain and examine the joints above and below the injured area, particularly if physical findings are normal in a joint that patients identify as painful (eg, shoulder pain in patients with a sternoclavicular joint injury).
X-rays are not necessary for many ankle sprains.
MRI can be used to diagnose soft-tissue injuries.
Immediately treat serious associated injuries and splint unstable injuries, and as soon as possible, treat pain.
Treat most minor injuries with PRICE (protection, rest, ice, compression, elevation).
Provide patients with explicit, written instructions about cast care.
Encourage patients, especially the elderly, to do the recommended exercises to maintain range of motion and muscle strength.