This site is intended for health professionals only

Sprains and strains: assessing the injury

Penny Keith
BA BSc RGN DN  
Nurse Practitioner Meadowell Centre (PMS for
homeless)
Nurse Practitioner Mentor
London South Bank University

Soft tissue injuries cover a multitude of conditions. For the purpose of this article the focus will be on the immediate management of common acute sprains and strains. A sprain or strain is a soft tissue injury of the ligaments and muscles - a sprain being an injury to a ligament and a strain an injury to a muscle.

Sprain
The degree of sprain is classified according to the extent of damage and the underlying integrity of the ligament (see Table 1).(1)

[[NIP25_table1_58]]

However, in acute presentation it is often difficult to differentiate due to pain, swelling and muscle tension, and often more subjective classification terms are used ranging from "mild" through "moderate" to "severe". The commonly affected joints are listed in Table 2.

[[NIP25_table2_58]]

Ankle sprains are the most common form of soft tissue injury treated in primary care, and of these about 50% occur as a result of participating in sports.(2)
 
Strain
An injury to a muscle where the muscle fibres have been stretched or torn. This is usually due to the muscle being stretched beyond its limits or being forced to contract too strongly. Strains are graded according to the severity of muscle fibre damage (see Table 3).(3)

[[NIP25_table3_59]]

Again these classifications can be hard to differentiate in practice due to pain, swelling and muscle tension, and so "mild", "moderate" and "severe" are subjectively applied.(4)
Muscle strains are the most common sporting injury, accounting for up to 55% of all such injuries.(3) The hamstring, rectus femoris, gastrocnemius and groin or adductor longus are the most commonly strained muscles.

Assessment of soft tissue injuries

Subjective assessment:

  • Mechanism of injury.
  • Timing of injury and presentation to healthcare professional.
  • Pain location, radiation and intensity (if sudden onset, could be calcification).
  • Stiffness.
  • If upper limb injury is dominant or nondominant.
  • Past medical history - checking particularly for anticoagulation treatment, epilepsy, haemophilia, previous episodes, and management and outcome.
  • Occupation and recreational activities - rule out domestic violence.
  • Medication.
  • Tetanus/diphtheria/polio status if skin broken.

Objective assessment

  • Observe injured limb from front, side and back.
  • Examine for possible fractures.
  • Check for pulse - should be palpable and capillary refill within two seconds.
  • Obvious deformity.
  • Bony tenderness.
  • Swelling and bruising - dependent on time since injury as it may take up to 24 hours to become apparent; muscle strain often results in a large haematoma and may be very painful if bleeding is contained within the muscle sheath.
  • Lacerations.
  • Wasting - compare with unaffected limb.
  • Neurological deficit.
  • Temperature of extremity.
  • Range of movement and power when active and passive.

Investigations
X-ray only if indicated or to rule out bony injury. Use Ottawa ankle and knee rules to decide if required (see Table 4).(5) Other differential diagnoses to be excluded.

[[NIP25_table4_59]]

Indications for referral

A&E or orthopaedics

  • Any neurological or vascular deficit, absent or decreased pulse.
  • Shoulder dislocation.
  • Fractured clavicle with skin tenting.
  • Compound fracture.
  • Dislocation requiring reduction.
  • Multiple fractures.
  • Unexplained deformity or swelling.
  • Sudden pain/redness, pyrexia suggestive of osteomyelitis, infective tenosynovitis.
  • Suspicion of deep vein thrombosis.
  • Possibility of domestic violence - needs sensitive approach and refer to local policies and guidance.

Plastics

  • Complex lacerations and ligament or tendon injuries.

Physiotherapy

  • Severe injuries requiring intensive or lengthy rehabilitation.
  • Major soft tissue swelling.
  • Functional deficit. (Use local criteria for any referral.)

Complications

  • Prolonged symptoms delaying the return to normal level of activity.
  • Loss of range of movement of affected joint.
  • Reduced power in surrounding muscles leading to muscle wasting.

Management
For a more comprehensive guide refer to the Prodigy Guidance.(1)

  • Assess the cause, circumstances and extent of injury.
  • Refer if necessary for emergency or specialist treatment.
  • Initiate short-term treatment with RICE - Rest, Ice, Compression, Elevation (see notes overleaf).
  • Treat pain with analgesics.
  • Advise early mobilisation starting usually after two days rest.
  • Prognosis - advice is dependent on site and severity of injury and usual levels of activity.
  • Follow up severe sprain or strain when swelling has subsided, about 7-10 days after injury, and review.

Rest
This reduces pain from movement. The evidence is mixed as to the benefit of rest, but early mobilisation is definitely advised.
Stabilise, protect and rest the affected part for up to 48 hours after injury, depending on levels of pain. Complete immobilisation is not indicated for sprains and strains treated in primary care.

Ice
This reduces pain, but there is only limited evidence that ice reduces swelling or restores function. Ensure that ice does not cause cold injury. Repeat application of ice about every two hours during the day.

Compression
This limits movement so is only applicable for the first 48 hours. The evidence base is very limited as there are no randomised controlled trials and there is no evidence that a double compression bandage is better than single. However, patient comfort may be a guiding factor in this.
Ensure any compression applied does not restrict the blood flow - advising patients to remove it if tissues become more painful or there is any loss of colour.
Do not use in peripheral arterial disease, and be careful with elderly and diabetics.

Elevation 
This may assist the reduction of swelling, although there is no evidence to support this.
Raise the injured part above the level of the heart if practical.

Analgesics

Paracetamol
This is the first choice for minor injuries. Use
regularly rather than "as required". For adults, recommend 0.5-1g every 4-6 hours to a maximum of 4g daily. For child doses see the NPF.(6)

Nonsteroidal anti-inflammatory drugs (NSAIDs)
These provide effective pain relief, but there is a greater risk of adverse effects than with paracetamol. NSAIDs may reduce healing time for sprains and strains and so may be useful to prescribe, where appropriate, for those wishing to return to full function or competitive sport.
Ibuprofen is the recommended first-choice NSAID. Do not prescribe for anyone with a known reaction, those with peptic ulceration or gastrointestinal bleeding, and care must be taken if prescribing for those with asthma.

Topical NSAIDs
Although these have a better gastrointestinal effect profile in comparison with NSAIDs, they may cause rash and have been shown to have a limited efficacy.(1)

Combination treatments
If paracetamol alone does not provide sufficient analgesia, consider prescribing codeine as a separate medication and titrate the two drugs to the patient's needs. Likewise, an NSAID with codeine phosphate may be a further option.
There is no good evidence to support the use of rubefacients or homeopathic arnica.

Compression bandages
Elasticated tubular bandaging may be prescribed following correct measurement for the affected limb or purchased along with many other products not available on FP10.
Patient information leaflets are available from Prodigy.(1)
Healing is usually within 1-6 weeks, but complete healing may take several months.
There is no evidence to support preventative measures such as stretching, although this is general good advice before any sporting activity, and there was a reduction in ankle sprains for those wearing external ankle supports.(4)

References

  1. Prodigy Guidance: Sprains and strains. Available from URL: http://www.prodigy.nhs.uk/guidance.asp?gt=Sprains%20 and%20strains
  2. Dutch College of General Practitioners. NHG practice guideline: ankle sprains 2000. Available from URL: http://nhg.artsennet.nl/upload/104/guidelines2/E04.htm
  3. Jarvinen TA, Kaariainen M, Jarvinen M, Kalimo H. Muscle strain injuries: current opinion. Rheumatol 2000;12(2):155-61.
  4. Garrick JG, Webb DR, editors. Sports injuries. Diagnosis and management. 2nd ed. London: Saunders; 1999.
  5. Bachmann L, Kolb E, Koller M, Steurer J, ter Riet G. Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ 2003;326:417-19.
  6. Nurse Prescribers' Formulary incorporating BNF 46. London: British Medical Association; 2003.