Definition

Muscle contusions and strains account for 90% of contact sport–related injuries [1,2]. Quadriceps muscle contusions result from blunt trauma to the anterior thigh and are encountered most commonly in contact sports such as football, soccer, basketball, and wrestling. Injury is caused by a direct hit from a helmet, shoulder pad, elbow, or knee or being struck by a puck while playing hockey [3]. The acute trauma damages muscle tissue, causing hemorrhage and subsequent inflammation. A contracted muscle will absorb more force and this will result in a less severe injury [4]. At 12 to 24 hours after the injury, quadriceps contusions are graded mild, moderate, or severe. A mild contusion has more than 90 degrees of knee flexion with normal gait; moderate, between 45 and 90 degrees of knee flexion with antalgic gait; and severe, less than 45 degrees of knee flexion with severely antalgic gait [4,5].

Symptoms

Quadriceps contusions may not be immediately evident after the contact injury. Pain, swelling, and decreased range of motion of the knee, particularly flexion, are seen within 24 hours. Symptoms may worsen with active muscle contraction and with passive stretch. Loss of knee range of motion can be the result of muscle and articular edema as well as of physiologic inhibition of the quadriceps muscle group and “splinting” due to pain. After injury, the quadriceps muscle group often becomes stiff, and the patient may have difficulty bearing weight on the affected extremity, resulting in an antalgic gait. Hemorrhage and resultant hematoma are described as either intermuscular (between the muscles) or intramuscular (within a muscle).

Physical Examination

Visual inspection of quadriceps contusion shows a variable amount of swelling and discoloration over the anterior thigh due to hematoma formation and intramuscular bleeding. Pain of varying intensity is present on palpation of the quadriceps muscle group. A firm palpable mass may be noted in the anterior thigh and is usually due to hematoma formation; if the hematoma formation is large, a knee effusion may also be present. Bone incongruity and tenderness may indicate fracture of the femur, patella, or tibial plateau. Check for the presence of distal pulses and capillary refill and assess range of motion of adjacent joints to be sure that the injury is localized to the anterior thigh.

Evaluation of range of motion reveals decreased knee flexion, especially past 90 degrees; knee extension will be less painful than flexion [6]. Extension lag or complete lack of extension is noted in partial or complete quadriceps rupture. With quadriceps tendon rupture, a palpable defect may be present. However, quadriceps rupture is a relatively rare injury more common in patients older than 50 years, and it is typically associated with underlying metabolic or inflammatory disease [7]. Muscle stretch reflexes of the patellar tendon may be inhibited, and serial measurements of thigh circumferences should be made during the initial 24- to 72-hour postinjury period to assess for possible compartment syndrome. Paresthesias, loss of pulses, distal pallor, intense pain, and decreased temperature should alert the clinician to consider this diagnosis (see Chapter 67). Sensory testing should include the femoral and saphenous nerve distribution of the distal leg.

An intermuscular hematoma with septal or fascial sheath hemorrhage may be more likely to disperse and to result in distal ecchymosis. If the contusion is in the distal third of the quadriceps, discoloration and swelling will often track into the knee region because of gravity. An intramuscular hematoma may resolve more slowly and may be associated with myositis ossificans and scar contracture.

Functional Limitations

Initially, gait will be antalgic and weight bearing difficult on the involved extremity. Rehabilitation typically occurs in three phases. In the first phase (first 24 hours), pain usually limits activity, and the patient may require crutches [8]. During a period of days to weeks, climbing stairs, running, and “kicking” activities will be limited secondary to knee stiffness and pain associated with terminal knee flexion and extension. Most patients recover uneventfully.

Diagnostic Studies

Plain radiographs are initially obtained in moderate to severe quadriceps contusions to rule out a coexisting fracture. Magnetic resonance imaging is the diagnostic imaging study of choice and allows visualization of the involved quadriceps muscles. Resolution of the injury, as detected by magnetic resonance imaging, lags behind functional recovery [9]. Ultrasonography may be helpful if tendon injury is suspected [10]. Nuclear bone scan may be ordered in the days to weeks after injury to assess for the development of myositis ossificans traumatica, heterotopic bone formation that may develop in up to 20% of injuries. Bone scans are more sensitive than plain films for detection of heterotopic bone formation and can be useful in monitoring its resolution. Suspicion of compartment syndrome warrants consideration of intracompartmental pressure monitoring, although conservative management in cases without concomitant fracture has been reported [9,11]. Compartment syndrome may be more likely in a patient with associated fracture or suspected large-vessel injury. For severe contusions or in a patient who appears ill, laboratory work is indicated, including creatine kinase activity, hematocrit determination, and possibly coagulation studies [12].

Immediately, the patient should cease activity. The knee is gently elevated and flexed to 120 degrees, and ice is applied to the anterior thigh (for 20 minutes at a time every 2 or 3 hours). A brace or elastic bandage should be placed around the injured leg and thigh to maintain 120 degrees of knee flexion as soon as possible after the injury and gentle compression applied to reduce hematoma formation for the initial 24-hour postinjury period [13]. After the initial 24 hours, the brace or bandage should be removed and active, pain-free range of motion of the knee should be initiated with static quadriceps strengthening and stretching [4]. If the injury is mild, icing is repeated for 2 or 3 days; the patient should ambulate with crutches, either non–weight bearing or partial weight bearing. In between icing, a thigh pad is applied. Temporary bed rest may be appropriate if the injury is severe. However, rehabilitation should be aggressive to the limit of pain tolerance. Avoid massage for the first 1 to 2 weeks after injury to lessen the chance of additional hemorrhage. Whirlpool, heat, and ultrasound modalities are avoided for the same reason until the edema stabilizes. If edema persists or becomes severe or warning signs of compartment syndrome develop, surgical referral is made to evaluate the possibility of compartment syndrome or ongoing hemorrhage. Needle aspiration of a formed hematoma may be indicated to relieve pressure and pain [14].

Determination of the appropriate time to progress the amount of activity performed and readiness for return to activity is important for recovery from injury. Animal models of muscle contusion suggest that continued use of the extremity promotes circulation and venous drainage, minimizing postinjury swelling. Because of the risk of hematoma formation, nonsteroidal anti-inflammatory drugs (NSAIDs) are avoided in the first 24 hours after injury. The role of NSAIDs in the treatment of muscle injuries is unclear because inflammatory cells are an important part of clearing away necrotic muscle followed by the regeneration and scar formation phase, leading to the question of whether NSAIDs help or delay the healing process [15]. The inflammatory response may be a necessary phase in soft tissue healing. Clinically, NSAIDs are used, but alternative analgesics like acetaminophen may be considered. However, in the animal model of quadriceps contusion, continued use of the contused muscle was more predictive of recovery than whether the animal received acetaminophen or NSAIDs [15]. Steroids should be avoided [1,4]. Medication use should facilitate continued rehabilitation and tolerance of activity progression.

Rehabilitation

Rehabilitation consists of three phases. The goals of the first phase are to limit bleeding, to immobilize the knee in full flexion, to elevate the leg for 24 hours, and to prescribe relative rest. Excessive activity or alcohol ingestion, which could aggravate the injury, is avoided. Phase two involves restoration of motion, the use of therapeutic modalities, and return to weight bearing. Crutches and partial weight bearing are used during this phase and until the patient has at least 90 degrees of knee flexion, good quadriceps control, and limited limp. After 48 hours from the injury and for the next 2 to 5 days, test range of motion with the patient in the prone position. Perform knee flexion exercises in the “pain-free range” with associated hip flexion. This can be followed with active-assisted range of motion exercises. It is important to avoid forced stretching because this may aggravate the injury and slow healing. Static quadriceps exercises can be instituted. Animal models of muscle contusion demonstrate that early mobilization increases tensile strength of muscle compared with immobilization [16]. Proprioceptive neuromuscular facilitation exercises using reciprocal inhibition of the quadriceps and hamstrings can be done as well [17]. Modalities may include pulsed ultrasound or high-velocity galvanic stimulation, with continuous pulses of 80 to 120 per second, at the patient’s level of sensory perception for 20- to 25-minute periods. Interferential electrical stimulation may assist in further edema resolution, but both ultrasound and electrical stimulation should be used once edema has stabilized. Cautious use of ultrasound can help increase blood resorption [17]. Cold compression may be useful to decrease pain and swelling.

Phase three starts when the patient has 120 degrees of pain-free range of motion and excellent quadriceps control. Noncontact sports and other vigorous physical activities involving the lower limbs may be resumed at this point, along with active knee range of motion, progressive resistive exercises, and cycling. Pain-free knee range of motion within 10 degrees of the unaffected extremity should be the goal before return to activity is considered. Jumping, sprinting, and cutting activities should be incorporated into the rehabilitation program, at which point functional testing to assess safe return to activity can be done. In the case of athletes, a protective pad larger than the original contusion should be worn during play for 3 to 6 months after injury. Most quadriceps contusions resolve within a few weeks, and complications are rare. If the patient does not have painless, full range of motion 3 to 4 weeks after injury, radiographic imaging should be performed to detect whether myositis ossificans is present. Time to return to activity is variable and depends on severity of injury; with severe contusions, full recovery is expected within by 5 to 8 weeks.

Procedures

On occasion, needle aspiration of a formed hematoma is performed to alleviate pressure and pain. This can be done at initial diagnosis or if symptoms are not responding to the measures outlined earlier.

Surgery

Surgery is rarely indicated with these injuries, except in association with a concomitant compartment syndrome or fracture. Untreated compartment syndrome may lead to muscle necrosis, fibrosis, scarring, and contractures. However, even in severe quadriceps muscle contusion, there is some indication that treatment should be conservative with pain management and maintenance of knee range of motion [9].

Potential Disease Complications

If the quadriceps region becomes extremely warm with marked increased edema and the patient complains of paresthesias with abnormal findings on neurovascular examination and significant quadriceps weakness, consideration must be given to the development of a potential compartment syndrome. A case of osteomyelitis has been reported in an otherwise healthy athlete who sustained a quadriceps contusion [18].

Myositis ossificans traumatica usually stabilizes and is resorbed spontaneously by 6 months after injury with conservative care [19]. Plain films may show ectopic bone formation 2 to 4 weeks after injury; the most common location is in the midshaft of the femur. Serial bone scans can be performed to monitor resolution of ectopic bone in a symptomatic athlete. Surgical removal of ectopic bone is rarely indicated and should not be performed for at least 12 months after injury to allow adequate maturation; this is to prevent enlargement of ectopic bone and recurrence. NSAIDs are the treatment of choice for prevention and initial treatment of myositis ossificans based on studies performed in hip replacements and related heterotopic ossification [4].

Potential Treatment Complications

Analgesics and NSAIDs have well-known side effects that most commonly affect the gastric, hepatic, and renal systems. Avoid vigorous soft tissue massage and passive stretch in the acute postinjury period to prevent further bleeding and hematoma formation (this occurs frequently in a field setting after hamstring injury).