Quadriceps Injury

Several types of quadriceps injuries can occur, the most common being the quadriceps contusion, which is painful and disabling. The usual cause of the quadriceps contusion is a direct blow to the anterior thigh from an object or another person (eg, helmet, knee). Very rarely, this injury can be severe enough to progress to an acute compartment syndrome.

Because the quadriceps is in contact with the femur throughout its length, it is susceptible to compression forces. The rectus femoris is the most commonly injured portion of the muscle because of its anterior location. Minimally, impact causes cellular edema of the muscle, but complete capillary disruption with localized hemorrhage leading to a tense anterior compartment can occur. The muscle is more resistant to injury if it is struck while in a contracted nonfatigued state. Other quadriceps injuries range from simple strains to more complex and disabling muscle ruptures. See the image below.

Other types of quadriceps injuries include strains of the quadriceps tendon, complete and partial tears of the quadriceps tendon, and fascial rupture of the quadriceps muscle. Specific areas of the quadriceps are affected for each of these diagnoses. The classic quadriceps strain occurs at the conjoined muscle tendon junction (jumper's knee). The partial tear of the quadriceps most commonly affects the indirect (distal) head of the rectus femoris. Fascial rupture usually occurs anteriorly at the mid thigh and causes a muscle hernia.

Causes of quadriceps injury are as follows:

• Quadriceps contusion or compartment syndrome - Direct blow to anterior aspect of thigh

• Quadriceps strain or rupture - Acute stretch or repeated eccentric muscle contractions with immediate or delayed (1-3 d) presentation of pain, stiffness, and decreased function

For patient education resources from eMedicineHealth, see Avoiding Sports Injuries, as well as Muscle Strain.

United States statistics

Although quadriceps strains are common, minimal information about the frequency with respect to specific sports is available. As for quadriceps contusions, the most detailed frequency data came from the US Military Academy at West Point,[1] and the distribution per year was reported as follows: rugby 4.7%, karate and judo 2.3%, football 1.6%, and all other sports fewer than 1%. Quadriceps muscle hernias are believed to be more common in soccer, basketball, and rugby.

A study by Eckard et al that analyzed data from the NCAA Injury Surveillance Program from 2009 to 2015 found that the on quadriceps strain injury rate was 1.07/10 000 athlete-exposures. Almost 78% of quadriceps strains were sustained during practice, however, the rate was higher during competition than during practice (approximately 1.3 versus 1.0/10 000 Athlete-exposures). The sports with the highest injury rates were women's soccer (5.61/10 000 AEs), men's soccer (2.52/10 000 AEs), women's indoor track (2.24/10 000 AEs), and women's softball (2.15/10 000 AEs). Overall, women had a higher rate of quadriceps strains than men.[2]

The incidence of jumper's knee at the quadriceps insertion onto the patella is less common than patellar tendinitis. One study reported that of all tendinopathies affecting the extensor mechanism, the frequency of patellar tendinitis at its insertion was 65%, quadriceps tendinitis was 25%, and patellar tendinitis at its insertion into the tibial tuberosity was 10%.

The estimated incidence of quadriceps tendon rupture is 1.37 cases per 100,000 persons per year.[3] Rupture of the quadriceps tendon is more common in both older patients and younger athletes. Several studies show that the mean age of patients with quadriceps rupture is about 65 years. However, in athletes, the mean age cited ranges from 15 to 30 years. Sports associated with quadriceps rupture are high jump, basketball, and weight lifting. Rupture is also not uncommon in patients with renal failure.

The quadriceps femoris acts as a hip flexor and knee extender. The quadriceps femoris is composed of the following:

• Rectus femoris

• Vastus lateralis

• Vastus medialis

• Vastus interomedialis

Origins/insertions of quadriceps components include the following:

• Rectus femoris - Ilium/tibial tuberosity

• Vastus lateralis - Femur/tibial tuberosity

• Vastus medialis - Femur/tibial tuberosity

• Vastus interomedialis - Femur/tibial tuberosity

The 3 thigh compartments are as follows:

• Anterior - Quadriceps muscles, femoral nerve and artery

• Posterior - Hamstring muscles, sciatic nerve

• Medial - Adductor muscles, cutaneous branch of obturator nerve

The function of the quadriceps is primarily that of tibial (knee) extension. One electromyography (EMG) study showed that the maximum extension moment and maximum quadriceps EMG activity were early in the kicking action, as the initial flexion changes to extension. This moment occurs before the foot makes contact with the ball. The peak activity of the hamstring occurs after the quadriceps peak, shortly before the ball is struck. The largest extension moment in this study was 260 Nm; this corresponds to a calculated tensile force in the patellar tendon of 7 times body weight.

The mechanical properties of the quadriceps have been studied. The central aspect of 10-mm wide sections of the quadriceps was subjected to tensile loading and compared to a similar patellar tendon section. The ultimate load to failure of the unconditioned patellar tendon was higher (53.4 N/mm2) than the unconditioned quadriceps tendon (33.6 N/mm2). Strain at failure was also higher for the preconditioned patellar tendon (14.4%) than for the quadriceps tendon (11.2%).

Microscopic sections of human quadriceps tendon as it inserts into the patella show no crimping and no cement line. This is unlike other tendon insertion sites. The interdigitation between collagen fibers and the distinction between tendon and bone was least distinct along the anterior third of the patella.

A discussion of the biomechanics of specific injuries is as follows:

• Strains, overuse, and rupture: The most common sites of injury correlate to the muscle tendon junctions both proximally and distally and to the muscle belly itself. Muscle strains are usually due to repetitive functional overload. Not surprisingly, quadriceps strains most commonly affect athletes who subject their knees to high levels of repeated loading of the extensor mechanism. The overuse trauma may range from microscopic failure of soft tissue with its associated inflammation or gross rupture. Gross rupture may be partial or complete. A large sudden load may cause the entire insertion to be compromised, leading to complete rupture. Repetitive loading, particularly eccentric loads, causes microfailure, usually at the muscle tendon junction. This microfailure can result in partial tears.

• Contusion: Direct trauma to the quadriceps may cause muscle fiber and connective tissue rupture and formation of a hematoma. Trauma to the quadriceps causes muscle fiber rupture, disruption of connective tissue, and hematoma formation. Inflammatory cells and macrophages enter the site of injury and begin clearing necrotic muscle cells. This process occurs over 2-3 days. Then, muscle cells attempt to regenerate at the same time scar tissue is being formed. A severe thigh contusion can lead to a compartment syndrome.

• Muscle hernia: The cause of this is not clear. It is usually associated with a sudden forceful kick, but it may be associated with a weakened or previously injured quadriceps fascia.

If treated properly, a full recovery is expected, although recovery times vary from days to months.

Complications

Myositis ossificans may occur at 3 or more months postinjury.

Quadriceps contusion

The mechanism is usually a blow to the anterior thigh with an object (eg, bat) or contact with another athlete (eg, knee, head) or gear (eg, helmet).

A severe trauma and large contusion can lead to a compartment syndrome. This diagnosis should be considered in patients with crush injuries, in patients with fractures resulting from high-energy trauma, in patients on anticoagulants, in patients with bleeding disorders, and in patients with multiple traumas.

A compartment syndrome of the thigh is very rare compared to compartment syndromes of the lower leg. The thigh compartments are much larger, allowing for tissue expansion, and the forces are distributed over a greater area. Unless rapid bleeding has occurred, these patients generally present with a gradual increase in their symptoms. The blood vessels injured usually are the deep perforating branches of the vastus intermedius (because of the direct attachment of that muscle to the femur).

Untreated, a compartment syndrome may lead to muscle necrosis, fibrosis, scarring, and limb contractures. Nerve injury may result either from the direct blow or from compression within the compartment.

Symptoms include painful anterior thigh, painful weightbearing, and unwillingness to flex the knee because of thigh pain.

Quadriceps tendon sprain

Blazina first described peripatellar tendinitis affecting the quadriceps tendon or the patellar tendon and termed this jumper's knee in 1973. He noted that it commonly occurred in jumping athletes.

The mechanism is sudden stretching or repeated eccentric contraction of the muscle causing pain and dysfunction immediately or 1-3 days later.

Symptoms include pain with ambulation and knee flexion and inability to extend the knee if the quadriceps is ruptured.

Quadriceps muscle partial tear

The mechanism is kicking or sprinting.

Incomplete intrasubstance tears of the rectus femoris tendon occur at the deep portion of the indirect head and the muscle there. The location, while along the distal part of the rectus femoris, is more proximal than the quadriceps strain at the patellar insertion.

Quadriceps tendon rupture

Many authors have concluded that the tendon usually ruptures in an area of tendinosis. In patients with bilateral injuries or injuries associated with trivial trauma and no history of previous strain, consideration should be given to the associated use of anabolic steroids or the diagnoses of renal disease and metabolic bone disease (hyperparathyroidism).

Special cases

This category includes ruptures after surgery. The surgeries that may be associated with this complication include lateral release, total knee replacement, or anterior cruciate ligament or posterior cruciate ligament reconstruction. Rupture of the quadriceps tendon after surgery may be associated with the procedure to harvest the graft used to reconstruct the cruciate ligaments or aggressive release of soft tissues in the case of lateral release and total knee replacement.

Quadriceps contusion

Features of quadriceps contusion are as follows:

• Normal medial and posterior thigh

• Tensely edematous and tender anterior thigh

• Limited knee flexion

  • Mild - Greater than 90°

  • Moderate - From 45-90°

  • Severe - Less than 45°

• For ruptures (complete and partial): Extensor lag indicates partial and complete tears; no extension indicates complete tear.

• Gait abnormalities

  • Mild - Normal

  • Moderate - Antalgic

  • Severe - Severe limp

• Knee effusion: Effusion may or may not be present.

• Exquisite anterior thigh tenderness with knee flexion

• Increased circumference of affected thigh

• Straight-leg raise: Patients are able to perform this unless the extensor mechanism is disrupted.

• Normal sensation in distal extremity: If sensation is compromised, consider compartment syndrome. The anterior compartment contains the femoral nerve, and testing of the lateral, intermediate, and medial cutaneous nerves should be performed if compartment syndrome is suspected.

• Pain: Disproportionately high level of pain for examination triggers suspicion of compartment syndrome.

Muscle strain

Tenderness is elicited by direct palpation of the quadriceps at the patellar insertion, or the patient reports pain when testing for resisted extension.

Quadriceps muscle hernia

A soft mobile mass, which may be tender, is palpated anteriorly with contraction of the quadriceps. A fascial defect may be appreciated.

Muscle partial tear

Thigh asymmetry with a nontender or mildly tender muscle mass at the distal aspect of the rectus femoris is a common finding.

Quadriceps tendon rupture

Characteristics of quadriceps tendon rupture are as follows:

• Inability to straight-leg raise (extensor mechanism disrupted)

• Muscular defect in distal anterior thigh with mass in proximal thigh

Blood studies are not generally indicated when the patient's history is that of overuse or sudden trauma. However, if the history and physical examination findings are suggestive of renal disease, hyperparathyroidism, soft tissue tumor, or diabetes mellitus, the appropriate studies should be sent.

The following are indicated for severe contusions and ill-appearing patients:

• Creatine kinase

• Hematocrit

• Coagulation studies - If patient develops spontaneous edema or is taking anticoagulants

Initially, imaging studies may not be indicated in patients with partial rectus tears, minimally symptomatic quadriceps contusions, and mild quadriceps tendinitis. These patients have a history of acute or repetitive trauma, and the history and physical examination findings are consistent with these working diagnoses. For patients in whom the history and physical examination findings are not consistent, for patients with night pain, patients with suspected complete quadriceps rupture, those with significant quadriceps contusion, and in patients where fracture (femur or patellar), metabolic disease, or tumor is suspected, radiography is indicated on the first visit.

For patients with mild tendinitis, mild contusions, and partial rectus tears who do not respond to activity modification, rest, and physical therapy, radiography is indicated on follow-up examination.

In patients with quadriceps contusion, plain radiography may show evidence of myositis ossificans at the site of the contusion several weeks to months after injury.

Patients who have quadriceps tendinitis or partial tears of the rectus tendon may have the radiographic findings of the so-called saw tooth patella along the proximal border of the patella.

Patients with complete rupture of the tendon may have an associated patellar fracture, particularly if the patient fell on the flexed knee at the time of the injury. The radiographs in patients with complete rupture show obliteration of the quadriceps tendon shadow, patella baja, and a large effusion. A suprapatellar mass (the retracted quadriceps muscle) or a suprapatellar calcific density may also be present.

If quadriceps tendon rupture is diagnosed clinically, anteroposterior (AP) and lateral views of the knee are the minimum views required. The lateral view shows a low-riding patella, patella baja, due to the unopposed pull of the patellar tendon.

CT scanning is not usually as helpful as MRI.

Ultrasonography is less expensive than the MRI and has a high sensitivity and specificity for complete tears. Its accuracy and predictive value in partial tears is not as good.

MRI has the highest sensitivity and specificity for disorders of the quadriceps. It shows both complete and partial ruptures, soft tissue hematomas, tendinopathies, soft tissue tumors, myositis ossificans, and fascial defects. Incomplete intrasubstance tears of the rectus femoris and complete tears of the rectus femoris and quadriceps tendon are visible as increased signal intensity on the T2 images. Incomplete intrasubstance ruptures of the rectus tendon and the quadriceps tendon image as focal disruptions of the normal laminated appearance of the tendon.

An MRI study by Falkowski et al found that quadriceps femoris tendon tears most often involve the rectus femoris or vastus lateralis/medialis layers, usually in proximity to the patella. Bony avulsion of the patella is correlated with a more extensive tear of the superficial and middle layers of the tendon.[4]

Compartment pressure measurements should be taken if compartment syndrome is suspected in the anterior thigh.

Rehabilitation Program

Physical Therapy

Therapy includes rest, immobilization, ice, and compression.

For a strain, stretching of the hamstrings, quadriceps, Achilles, and iliotibial band should be started gently and then become more aggressive as pain permits.

Medical Issues/Complications

In one study, only one third of patients with acute quadriceps tendon rupture were accurately diagnosed at the first visit. Therefore, if complete rupture is suspected but the diagnosis cannot be confirmed clinically, MRI is the study of choice. Late diagnosis of a complete tear of the quadriceps tendon can lead to retraction of the muscle proximally with scarring. The consequence of this is that the surgical repair is more difficult and the clinical results are not as good.

Surgical Intervention

Surgical intervention is indicated for compartment syndrome (decompressive fasciotomy), hematoma removal, complete quadriceps muscle rupture, and bony avulsion of muscle insertion at the patellar tendon.

Complete quadriceps rupture or bony avulsion

The indications for surgery include complete quadriceps tendon rupture and bony avulsion of the quadriceps in patients who can tolerate surgery. The reason for this is that without an intact extensor mechanism, walking and standing are very difficult to impossible, even with braces. For patients who are nonambulatory and who do not stand, nonoperative management may be considered for the diagnosis of quadriceps rupture or avulsion.

The surgery may be completed under a regional anesthetic. In the setting of acute trauma, within 7-14 days of injury, a primary direct repair using nonabsorbable sutures is the recommended procedure. The sutures are placed through the quadriceps tendon and then threaded through drill holes in the patella. The sutures are tied over the distal pole of the patella. In patients with metabolic or renal disease or in those in whom the repair appears tenuous because of underlying tendinopathy, consideration should be given to augmenting the repair with a cerclage wire or cables.

For patients who present later or for those with chronic ruptures, a Z-lengthening of the tendon may be required. These patients may also need augmentation of the repair.

After surgery, a typical rehabilitation program has the goals of early motion and weightbearing without compromising the repair. These goals can be challenging in the setting of underlying tendinopathy, metabolic disease, or repair of a chronic tear. A trend for more aggressive rehabilitation is quite popular. However, before advancing to the next phase and during each phase of the rehabilitation program, the patient should be reevaluated to ensure that the repair remains intact and that no soft tissue swelling or effusion is present.

For uncomplicated repairs, the patient is placed in a rehabilitation brace, locked from 0-30 º of flexion. Weightbearing as tolerated is allowed. After 4-6 weeks, the range of motion is increased to 60 º. From 6-8 weeks, the range of motion is increased to 90 º. The goal of flexion is 90 º, although most patients obtain more flexion. Weightbearing is gradually increased. Patellar mobilization is started at 6-8 weeks. A brace is prescribed for 3-6 months. Contact sports are restricted for 9-12 months.

Chronic partial rectus femoris tears

These patients are candidates for excision of the partial tear if they do not improve with a rehabilitation program and the diagnosis is confirmed by MRI.

Consultations

An orthopedic surgeon should be consulted for compartment syndrome or quadriceps rupture (complete or partial) at the insertion on the patella.

Other Treatment

For a quadriceps contusion, immediately putting the knee in 120° of flexion (first 10 min) tamponades the hemorrhage and limits muscle spasm. This provides a more rapid return to normal range of motion. This aggressive treatment minimizes the risk of developing myositis ossificans. If the knee is left in extension, the quadriceps starts to heal in a shortened position and the patient experiences a more painful and slower return to full flexion capacity. The same treatment is also recommended for quadriceps strains (see the image below).

Simple contusion care

Immobilize knee in 120° of flexion with elastic bandage or adjustable knee brace for 24 hours. This should be completed by wrapping the knee in a figure-8 fashion with 2- X 6-inch ACE wraps that have been sewn together end-to-end.

Crutches are needed.

Apply ice for 20 minutes every 2-3 hours.

Discontinue 120° of flexion at 24 hours and begin electrical stimulation and/or passive stretching, followed by icing.

Begin active pain-free quadriceps stretching and strengthening several times a day.

Gradual return to weightbearing is indicated.

Avoid applying heat to the area because it may increase swelling.

Modified treatment regimen

This should be used for the quadriceps contusion that is not brought to medical attention until after intramuscular bleeding and spasm have limited knee flexion significantly. (See the following image)

Patient should remain in the prone position.

Bring the knee to maximum amount of pain-free flexion.

From this flexed position, resist the patient's attempt to extend the knee. This isometric contraction should be relaxed when the patient experiences fatigue in the injured muscle. The intent is to relax the spastic muscle by fatiguing it.

As the muscle fatigues, perform passive quadriceps stretching by taking the knee into flexion while in the prone position.

Repeat this combination of extension, relaxation, and flexion 3 times and then immobilize in the maximum amount of pain-free flexion.

Use crutches while immobilized.

Repeat this process twice a day and increase the number of repetitions.

Immobilization/bracing may be discontinued when 120° of flexion is achieved.

Crutches may be discontinued when vastus medialis muscles are equal in size and tone.

Rehabilitation Program

Physical Therapy

Patient should continue to be monitored and work on stretching, range of motion, and quadriceps and hamstring strengthening.

Protected weight-bearing combined with immobilization has been routinely recommended after surgical repair. Early functional rehabilitation can support solid healing and lead to normal function. A clinical trial compared early functional rehabilitation with a prolonged period of immobilization. Early functional postoperative mobilization with full weight-bearing after primary repair of a quadriceps tendon rupture was noted to be safe.[5]

Recreational Therapy

When the player returns to activity, a protective pad larger than the injury site should be worn over the contused area for the duration of the season.

Medical Issues/Complications

Myositis ossificans traumatica occurs in approximately 9% of patients with quadriceps contusions.

• Occurs 3 or more months after initial injury

• Should be differentiated from a soft tissue tumor

Diagnosis requires at least 50% calcification to be observed on radiography.

Treatment may require excision of heterotrophic bone formation, although most people return to full activity without special treatment.

The incidence of myositis ossificans increased with 3 or more of the following risk factors:

• Initial range of motion less than 120°

• Repeat injury to quadriceps

• Knee effusion

• Football injury

• Treatment delayed more than 3 days

Surgical Intervention

If patients have a partial intrasubstance tear of the rectus femoris and do not improve with a rehabilitation program, they may be candidates for surgical removal of the tear.

Patients with quadriceps muscle hernias do not usually meet the criteria for surgery.

Possible heterotropic bone excision may be indicated for symptomatic myositis ossificans.

Return to Play

Return to play may vary from 2 days to 10 weeks, depending upon the severity of the injury and the postinjury care. The player may resume play when 120° of flexion is achieved and no evidence of quadriceps weakness or atrophy is present. If treated properly with the immediate 120° of flexion, the player can return to play in 2-5 days. A protective pad larger than the area of contusion should be worn for the remainder of the season.

Prevention

Remove player from activity at the time of initial injury because the risk of a more severe injury is increased when the player is already in a weakened state. Protective padding should be worn in sports with high risk for quadriceps injury and by players who have already sustained such an injury.

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of muscular injuries is controversial. Inflammatory cells are a necessary and important part of the clearing away of necrotic muscle fiber. This process is followed by the regeneration and scar formation phase. Based on this, interfering with the inflammatory response may, in fact, delay healing.

A compelling reason for using NSAIDs does not appear to exist, and their cost and potential adverse effects should also be taken into consideration.[6] If used at all, it should be early in the inflammatory period (first 2-3 d) and not once the actual regeneration has begun. Corticosteroids are also believed to have a negative effect on healing. Anabolic steroids may prove to be helpful in muscle healing but are not currently part of management.