eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Knee Injury, Soft Tissue: Treatment & Medication

Author: David B Levy, DO, FACEP, FAAEM, Chairman, Department of Emergency Medicine, St Elizabeth Health Center; Associate Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine
Coauthor(s): Howard I Dickey-White, MD, Teaching Attending Physician, Department of Internal Medicine, St Elizabeth Hospital Medical Center; June E Sanson CNRP, MSN, Nurse Practitioner, Take Care Health Systems
Contributor Information and Disclosures

Updated: Dec 15, 2009

Treatment

Prehospital Care

• Basic responsibilities in the prehospital setting, if knee trauma is the primary injury, include stabilizing the lower extremity and monitoring the neurovascular status of the limb.
• The deformed knee should be realigned only if associated neurovascular structures are compromised.
  • Always recheck and document pulses after splinting or manipulation of the limb.
  • If initial efforts meet with resistance, prehospital personnel should not force realignment.
• Cover open wounds with saline-soaked sterile gauze.
• Frequently, the joint reduces spontaneously or is reduced at the scene by trained emergency medical services (EMS) personnel; in such cases, the ED physician must obtain information about the time and mechanism of injury and the original position of the limb.

Emergency Department Care

Adhere to the conventional dictums of emergency and trauma care by first corroborating the absence of life-threatening (primary survey) or limb-threatening (secondary survey) injuries before focusing on soft-tissue damage sustained by the knee. A cardinal error occurs when earliest attention is diverted to an obvious extremity injury, such as a knee dislocation, while neglecting possibly lethal trauma.

• Always determine the mechanism of injury and verify hemodynamic stability.
• Assess vascular perfusion and control any bleeding.
  • Hard signs of vascular injury include absent or diminished pulses, active hemorrhage, and expanding or pulsatile hematoma.
  • Signs of distal ischemia include pain out of proportion to the injury, pallor, paralysis, and paresthesias.
  • For knee dislocations or grossly malaligned fractures with potential vascular compromise, attempt immediate reduction or realignment of the knee if an orthopedic specialist is not immediately available.
  • Popliteal-artery injuries must be repaired within 6-8 hours to avoid amputation because of limb ischemia.
• Splint all obvious fractures and unstable knee injuries, stabilizing the femur above and the tibia below.
• Damage to essential nerves and vessels may be subtle on presentation.
• Observe for signs and symptoms of compartment syndrome. Measurement of compartment pressures is often needed to exclude the possibility of compartment syndrome.
• Remove any constricting clothes and bandages.
• Make sure patients ingest nothing by mouth (NPO) until the need for emergency or urgent surgery is ascertained.
• General treatment principles include the following:
  • Aside from the particular injury, treatment plans depend on the patient's age and activity level and the presence of additional injuries.
  • Obtain orthopedic consultation when appropriate.
  • Initial nonpharmaceutical treatment includes rest, ice, compression, and elevation (RICE).
  • For the first 1-3 days, use therapeutic measures that minimize incipient damage and reduce pain and inflammation.
  • Consider splinting the injured knee to provide support and to prevent further injury.
  • Serviceable devices include commercially available immobilizers and handcrafted compressive dressings, such as the Robert Jones dressing, which incorporates coaptation plaster.
  • Detrimental effects of immobilization include joint stiffness, degenerative changes in articular cartilage, muscle atrophy and weakness, and decreased vascularity.
• Therapy for specific injuries include the following:
  • For first-degree sprains, provide symptomatic treatment, essentially the RICE regimen. Normal function usually returns quickly.
  • Second-degree sprains require protection by using a cast, cast brace, or a restrictive movement brace. Arrange for timely follow-up care.
  • Treatment of third-degree sprains depends on the severity and type of instability; some third-degree sprains of ligaments necessitate surgical repair. Factoring into the deliberation for surgery is the patient's age, relative health, associated injuries, activity demands, and individual desires.
  • Treatment for anterior cruciate ligament (ACL) injuries is individualized. Various conditions influence decisions on the optimum management of ACL tears, such as the presence or absence of comorbid pathology, age of the patient, baseline activity level, degree of instability, and associated ligamentous injuries miring the knee.
  • Presence of a meniscal tear does not automatically lead to surgical intervention. If the knee is not locked or unstable, conventional treatment (ie, RICE therapy) ordinarily suffices; however, the meniscus cartilage of the knee generally supports a precarious blood supply, and tears are prone to inadequate mending. Therefore, timely follow-up care is critical.
• Emergency consultation with an orthopedic specialist is required for immediate reduction and evaluation of vascular integrity after a knee dislocation. If expedient orthopedic consultation is not obtainable and if signs of vascular compromise are present, the ED physician should undertake maneuvers to restore both integrity of the joint and perfusion. (See Dislocations, Knee for specific reduction techniques.) Angiography is imperative.
• Reduction of knee dislocation includes the following:
  • Most knee dislocations reduce spontaneously before the patient's arrival in the ED. However, when examination findings suggest neurovascular compromise, an attempt to restore circulation with traction and/or reduction and emergency orthopedic consultation are needed.
  • Classify dislocations with respect to the relationship of the tibia on the femur.
  • Anterior dislocations occur most commonly.
  • In the ideal case, perform reductions in the operating room under general anesthesia. However, if circumstances preclude this scenario, an attempt in the ED is warranted.
  • Barring contraindications, administer conscious sedation.
  • With an assistant providing stabilization and countertraction of the thigh, a second person applies longitudinal traction to the leg. This maneuver usually suffices for reduction.
  • Reduction of an anterior knee dislocation may be aided by trying to transpose the femur anteriorly.
  • Avoid affixing pressure over the popliteal space as it may exacerbate arterial damage.
  • For posterior dislocations (where the tibia lies posterior to the femur), attempt to reinstate the tibia anteriorly by gently lifting the tibia forward.
  • After relocation of the knee, confirm neurovascular status and immobilize the knee in 15° of flexion.
  • Order postreduction images and consultation with the orthopedic surgeon, and obtain an emergency arteriogram.
• Reduction of patellar dislocation includes the following:
  • Patellar dislocations typically occur in predisposed individuals and tend to recur.
  • Patellar dislocations are identified with respect to the patella's position on the knee joint, with lateral dislocations being most common.
  • If the joint has not already reduced spontaneously, verify the dislocation radiographically.
  • After administering necessary analgesia, place the hip in a mild amount of flexion, and gently press anteriorly and medially on the patella while extending the knee joint.
  • Postreduction films should include a sunrise view, as osteochondral fractures may result.
  • Other types of patellar dislocations tend to be resistant to closed reduction.
  • Aspiration of a Baker cyst may render temporizing relief. This procedure is best performed electively by a qualified physician.
• Injection therapy
  • Ensure that the joint is not infected.
  • Pain secondary to aseptic inflammation of the prepatellar, suprapatellar, and pes anserine bursae may be relieved by instilling 2-4 mL of lidocaine mixed with 15-20 mg of a prednisolone suspension into the affected bursae.
  • Recent data have suggested that an intra-articular installation of morphine 1-5 mg confirms a local analgesic effect and possibly prolongs pain relief compared with systemic opioids.
• Reducing the locked knee
  • Avoid undue manipulation because it may aggravate internal derangement.
  • A simple measure to reduce the locked knee involves positioning the patient with the knee dangling over the edge of the examination table in 90° of flexion.
  • Gravity usually expedites distraction of the tibia from the femur, thereby promoting unlocking.
  • If this technique fails after a reasonable time period, tempered rotation of the knee along with caution traction on the leg usually frees the knee joint.

Consultations

Depending on the degree of knee instability, affected ligaments, and the patient's age and baseline activity level, early surgical intervention may be the best option.

• Indications for emergency or urgent orthopedic consultation include the following:
  • Gross knee dislocation or unstable knee
  • All knee injuries with associated neurologic or vascular injury
  • Complete quadriceps tendon rupture or a complete patellar tendon rupture
  • First-time patellar dislocations and patellar displacements accompanied by an osteochondral fracture
  • Open joint injuries of the knee

Medication

In addition to resolving the etiology of the knee pain, the ED physician must make every effort to relieve suffering as completely and expeditiously as possible. Distinguish acute injury from chronic distress. Consider the intensity of the pain. The perception of pain is subjective, and therapy should be individualized.

Objective parameters, such as tachycardia, are unreliable. Minor trauma to the knee that involves the ligaments, muscles, and joints usually causes a mild to moderately severe, self-limiting discomfort. An enormous choice of analgesics is available for use by the ED physician, but pharmacologic agents tend to fall into 2 general categories: nonnarcotic and narcotic analgesics. Furthermore, consider the best route for delivering the drug.

Nonnarcotic analgesics

Patients with pain accompanying minor acute soft-tissue injuries of the knee generally benefit from a short course of nonnarcotic analgesics, with acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) being the most frequently prescribed agents. If inflammation is a component of the injury and if no contraindication is present, prescribe NSAIDs, as acetaminophen lacks anti-inflammatory properties. An increasing number of NSAIDs are available for use. NSAIDs share a common mechanism of action, which involves inhibiting the production of pain-mediating prostaglandins. In general, NSAIDs provide a comparable degree of pain and inflammatory relief, but they differ in dosing schedules.

Choosing an NSAID to prescribe can be perplexing; data comparing these agents are meager, and individual responses are inconsistent. Because no individual NSAID is clearly superior, base decisions on personal experience, safety profiles, cost, and convenience.

Acetaminophen (Tylenol, Feverall, Aspirin Free Anacin)

Most commonly ingested pain reliever; marketed in combination with other drugs to provide analgesia. Advantages include availability, cost, and relatively good safety profile. Onset of relief usually in 20-30 min. Extended-release preparations do not appear to offer major benefits (other than dosing convenience) and may increase incidence of toxicity. For children, available as drops (80 mg/0.8 mL), elixir (160 mg/5 mL), tablets (80, 160, or 325 mg), and suppositories (125 or 325 mg).

Acetylsalicylic acid (Bayer Aspirin, Bufferin, Anacin, Ecotrin)

Prototype NSAID; used in combination with many other drugs; available OTC. Offers anti-inflammatory benefits, unlike acetaminophen. Effective in PO, suppository, and topical preparations. Therapeutic anti-inflammatory serum level 15-30 mg/dL.

Ketorolac (Toradol)

Choice of parenteral pain medications dispensed in ED. Frequently overlooked fact is that this medication is an NSAID, with all of the group's attendant risks and that it costs almost 20 times more than morphine (and 140 times more than ibuprofen). Data supporting superiority over other analgesics scarce.

Ibuprofen (Motrin, Advil, Nuprin)

Widely used NSAID, also available OTC, derivative of propionic class of NSAIDs and considered safest of NSAIDs. Available as tablets 200, 400, 600, and 800 mg; pediatric dosage forms available as tab and PO suspension (20 mg/mL). Advise taking with food or milk if possible; caution in children with flulike illnesses.

Narcotic analgesics

Patients reporting inadequate pain relief from NSAIDs may benefit from short-term supplementation with an opioid compound. A wide array of products is available. PO hydrocodone (Lortab, Lorcet, Vicodin, Anexsia), schedule III narcotic, and oxycodone (Roxicet, Percodan, Tylox), schedule II substance, usually provide additional pain relief. Codeine-containing products (schedule III) are not as reliable for alleviating pain. Although relative potencies of oxycodone and hydrocodone are approximately 0.33 of those with parenteral morphine, PO codeine is 0.05. Mixed agonist-antagonist PO agents (eg, butorphanol, nalbuphine, pentazocine), offer no real advantages to opioid agents yet increase incidence of adverse effects. Common adverse effects include constipation, nausea, respiratory depression, sedation, and urinary retention.

General approved dosage of hydrocodone is 5-10 mg combined with acetaminophen 500-750 mg administered PO q6h prn. Oxycodone analgesic preparations typically combine 2.5-5 mg of oxycodone with 325 mg of acetaminophen, dosed as 1-2 tabs PO q4h prn for moderate to severe pain. Acetaminophen with codeine (Tylenol #3) contains 30 mg of codeine with 325 mg of acetaminophen. Usually, 1-2 pills q4h prn is recommended.

Elixirs containing hydrocodone (Hycodan) are convenient for children older than 6 years with moderately severe to severe pain and who are unable to swallow pills. One teaspoon (5 mL) of Hycodan contains 5 mg of hydrocodone, with 1.25-2.5 mg administered q4h, depending on the child's size and severity of pain. The elixir of Tylenol with codeine for children contains 120 mg of acetaminophen and 12 mg/5 mL of codeine in an alcohol base (7%).

Orally administered drugs generally impart a slower onset of action. For patients in severe pain or for those patients who must be kept NPO, parenteral agents may be necessary. Although the IM route may be more convenient for the staff, the IV route offers a number of advantages. Narcotics administered IV provide a rapid and predictable onset of action and are easier to titrate. Morphine and meperidine are the most commonly used parenteral narcotic agents.

Hydrocodone and acetaminophen (Vicodin, Lorcet, Lortab, Anexsia)

Drug combination indicated for relief of moderately severe to severe pain.

Oxycodone and acetaminophen (Percocet, Tylox, Roxicet)

Drug combination indicated for relief of moderately severe to severe pain.

Acetaminophen and codeine (Tylenol #3)

Drug combination indicated for treatment of mild to moderately severe pain.

Morphine sulfate (Oramorph, MS Contin, Duramorph)

Criterion standard for relief of acute severe pain; may be administered in a number of ways; commonly titrated until desired effect obtained. IV morphine demonstrates half-life of 2-3 h; however, half-life may be 50% longer in the elderly.

Meperidine (Demerol)

Narcotic analgesic with multiple actions similar to morphine; however, may cause less constipation, smooth muscle spasm, and depression of cough reflex than similar analgesic doses of morphine. Serum half-life 2 h. Metabolism occurs by hepatic demethylation into normeperidine. Patients with moderately severe to severe liver disease may develop excessive levels of metabolites, precipitating CNS adverse effects, including tremors and seizures.

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