Thigh Compartment Syndrome
Compartment syndrome of the thigh is a rare clinical entity. It occurs less frequently than compartment syndrome of the calf due to the thigh’s ability to accommodate larger volumes of fluid. Of the three compartments within the thigh—anterior, posterior, and medial—the anterior compartment is most commonly affected (Fig. 19–1).26,27
Blunt trauma accounts for approximately 90% of cases of acute thigh compartment syndrome, with motor vehicle collisions being the most common traumatic mechanism.28 However, many causes of thigh compartment syndrome have been identified, including femoral shaft fractures, muscle contusion or rupture, revascularization injury, external limb compression, and even anticoagulant-induced bleeding into the thigh.27–32 In all cases, the underlying pathophysiologic mechanism is similar to that of other compartment syndromes, in which increased pressure within the limited compartmental space exceeds perfusion pressure, leading to circulatory compromise.
Like other compartment syndromes, the patient will present with severe pain that is exacerbated by passive stretch of the muscles within the involved compartment. The compartment is often swollen, tense, and exquisitely tender to palpation. Late findings may include sensorimotor deficits distal to the thigh. Anesthesia or paresthesia may be an early indication of nerve ischemia, whereas muscle paralysis is often a late sign indicating irreversible muscle and nerve damage.30
Similar mechanisms of injury and clinical symptoms make compartment syndrome of the thigh often difficult to distinguish from severe contusion. Therefore, the diagnosis is often made both clinically and with the aid of intracompartmental pressure measurements.28
Although CT, MRI, and ultrasound have been studied for the diagnosis of compartment syndrome, their use is currently limited and may delay definitive management.30
The high-energy trauma often involved in thigh compartment syndrome will result in many soft tissue and musculoskeletal injuries. Femur fractures are associated with up to 44% of cases of thigh compartment syndrome, interestingly with almost one quarter of these being open fractures. Severe complications, including neurologic deficits, infection, and renal failure are very common. Mortality rates as high as 47% have been reported, most often due to polytrauma and infection.28
The definitive treatment for thigh compartment syndrome is emergent surgical fasciotomy. The primary cause of poor outcomes from compartment syndrome is a delay of treatment.30 The generally accepted indication is a difference between diastolic pressure and the measured compartment pressure of less than 30 mm Hg, although this is of continued debate.28,30 Successful outcomes with conservative management involving bed rest, frequent compartment pressure measurements, cooling, and serial clinical examinations have been described in the absence of fracture.30,33 Nevertheless, early fasciotomy is important to prevent complications of delayed diagnosis, and early surgical consult should be obtained in any patient suspected of having thigh compartment syndrome regardless of compartmental pressures.
Quadriceps contusions, after muscle strains, are the second most common type of quadriceps injury in athletics, comprising approximately 14% of all thigh injuries in high school sports and 19% of all muscle injuries in professional soccer.34,35
The usual mechanism of injury is a direct blow to the quadriceps muscles, often from an opponent’s knee or sporting equipment.34 This compresses the underlying muscle and soft tissues against the femur causing myofiber and capillary rupture, forming a hematoma.36
The patient will often report a traumatic mechanism and complain of localized pain. The ability to play following injury, as well as the time interval between injury and presentation, are important indicators of injury severity and prognosis.35 Physical examination will reveal tenderness to palpation, swelling, and often ecchymosis at the site of injury (Fig. 19–7). If signs such as pulselessness, paresthesia, or paralysis suggestive of compartment syndrome are found, early surgical consultation should be considered and intracompartmental pressures obtained.
A clinically and prognostically useful classification system grades quadriceps contusions as mild, moderate, and severe.37 In a mild contusion, the patient has localized tenderness, no alteration of gait, and knee motion without pain up to at least 90 degrees of flexion. In a moderate contusion, the patient displays swelling and a tender muscle mass. Knee motion is restricted to <90 degrees and the patient walks with an antalgic gait. The patient is unable to climb stairs or arise from a chair without considerable discomfort. In patients with severe contusions, the thigh is markedly tender, swollen, and indurated. Knee motion is severely limited (<45 degrees), and there is either a severe limp or the patient is unable to ambulate. Average disability times are progressively longer with increased severity: 13 days for mild, 19 days for moderate, and 21 days for severe.38
The diagnosis of quadriceps contusions is usually a clinical one. However, imaging may be useful in distinguishing contusions from avulsions and strains, especially when the presentation is subacute. Ultrasound and MRI are sensitive indicators of soft-tissue injury; however, the availability of ultrasound in the emergency department makes it particularly useful in this circumstance. Hematoma on ultrasound will appear as interruption in the normal architecture of the muscle with localized hypoechogenicity.36,39
Treatment of thigh contusions is often approached in a staged manner from the time of injury. The immediate goal is to control propagation of the hematoma by immobilizing the knee of the contused thigh in 120 degrees of flexion for 24 hours.34 This can be done either by an elastic wrap or adjustable brace and should be done as soon as possible after the injury occurs. Ice and compression should also be employed during this time and the patient should ambulate with crutches. In one study involving naval athletes who received immobilization within 10 minutes of injury followed by range-of-motion stretching as described below, the average time from injury to return of unrestricted full athletic activity without disability was 3.5 days.40
After the brace is removed, the patient should engage in active pain-free range-of-motion stretching of the involved thigh. Once the patient is able to attain 120 degrees of pain-free motion in the ipsilateral knee, functional rehabilitation should begin and the use of crutches may be discontinued. In athletes, the use of a thigh pad to prevent recurrent injury to the site of the contusion should be encouraged.40
The effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on muscle injuries is thought to be paradoxical, with early use leading to improvement but sustained use leading to impairment in functional capacity and histology.41 NSAID use in the first 3 days appears to have no detrimental effect.42 Corticosteroids are not an effective adjunctive therapy for thigh contusions.34
Myositis ossificans occurs as a complication in up to 17% of muscle contusions.34 It should be suspected if symptoms worsen 2 to 3 weeks after the initial injury. Risk factors for development of myositis ossificans include associated knee effusion, severe injury, and delay in treatment.38 Compartment syndrome is also a potential complication especially in contusions with large hematoma formation.43
Muscle Strains and Rupture
Adductor muscle strains are the most common groin injury in athletes.44 The sports with highest prevalence of this injury include ice hockey and soccer, where strong eccentric contraction of the adductor muscle group is required.45 This injury is usually caused by forced abduction of the thigh. Decreased adductor strength and range of motion are both risk factors for the development of adductor strains.44
The patient complains of pain that is localized to the groin region. With incomplete rupture, the pain is made worse by passive abduction of the thigh and is accentuated by active adduction against resistance. Ecchymosis may be present (Fig. 19–8). If complete rupture has occurred, the examiner will often see bunching of the muscle along the medial aspect of the thigh near the groin.
Pattern and degree of ecchymosis raises concern for adductor muscle strain or rupture.
Imaging is not necessary unless the diagnosis is in question. Ultrasound may be used to diagnose adductor muscle or tendon tears but not strains. MRI can be used to confirm a muscle strain or tear, and has prognostic value but is generally not needed for the diagnosis. Pelvis radiographs should be obtained if there is concern for avulsion injury at the origin of the adductor longus.
Adductor strains should be treated with relative rest, ice, and short-term use of NSAIDs followed by physical therapy. A return to sports is allowed once the patient has regained at least 70% of their former adductor strength and pain-free full range of motion. This process can take approximately 4 to 8 weeks.
Chronic adductor strains may require up to 6 months of physical therapy. Failure to respond to prolonged physical therapy may be an indication for surgical referral for tenotomy.44
Complete rupture of the tendinous insertion of the adductor warrants surgical referral for repair.
Hamstring strains are common in runners, water skiers, hurdlers and in other sports that involve jumping and kicking such as soccer. The mechanism is usually sudden, forceful flexion at the hip with extension at the knee. Prior hamstring injury is a risk factor for hamstring strain. Other potential risk factors include patient age, lack of hamstring flexibility, and increased peak quadriceps torque.46
The patient will present with acute onset of posterior thigh pain. There will be pain with weight bearing and an antalgic, stiff-legged gait that usually inhibits athletic activity.
Examination should be performed with the patient in the prone position with the knee flexed. There is usually swelling in the posterior thigh with tenderness to palpation. Severe injuries may be accompanied by ecchymosis in the posterior thigh. The examination should include thorough palpation of the entire muscle belly searching for a defect that represents a tear. Complete tears of the hamstring musculature are rare.47
Knee flexion should also be tested. If there is less than 30% strength compared to the contralateral uninjured limb and significant posterior thigh or knee ecchymosis, consider an MRI to evaluate for possible proximal hamstring rupture.46
Usually the diagnosis of a mild strain is clinical and no imaging is necessary. Plain films are useful in more severe injuries to identify whether avulsion has occurred, as the avulsed segment of bone may be visible. In the case of suspected rupture or avulsion, MRI is an important tool that may affect surgical decision-making.46 Some studies have shown that the size of the strain’s appearance on MRI may correlate to time lost from sporting activity.47,48
The acute treatment for hamstring strains includes rest and rehabilitation, ice, compression, and elevation usually for 3 to 7 days. The goal of this treatment is to limit the initial inflammatory response, control hemorrhage and edema, and improve pain.46 NSAIDs are also used during this time. Gradual mobilization as tolerated is made over a period of 2 to 6 weeks depending upon injury severity, and crutches may be used initially until pain-free ambulation is possible.
The risk of hamstring strain recurrence is high, with athletes shown to have 20 times the risk of recurrence in the first 3 weeks back in play compared to their noninjured peers. A progressive agility and trunk stabilization program may reduce the reinjury rate. Stretching has not been definitely shown to improve recurrence rates. To avoid reinjury, the patient should be advised to avoid early return to sports until they are appropriately rehabilitated.47
The rectus femoris, adductors, and hamstrings can rupture anywhere from their origin to their insertion. The patient is often misdiagnosed as having a contusion, and often there is a delay in diagnosis. Surgery is more complicated and less effective on chronic ruptures, stressing the importance of timely diagnosis. The telltale signs and symptoms develop with time, and may not be present in the acute setting. This emphasizes the need for appropriate instructions to follow-up if the mechanism suggests tendon rupture. Recommend close follow-up to patients if they develop a large ecchymosis, a muscle bulge, or they have weakness with knee flexion. Rupture can occur when a tendon is suddenly eccentrically loaded. For example, hamstring ruptures usually result from sudden flexion at the hip with knee extension. These injuries are more common in water skiers, and can also occur if a patient slips on an icy surface with their leg outstretched. Educate patients to look for the development of a large ecchymosis, or a mass (suggesting the tendon/muscle is retracted) and weakness.46
The examination should include inspection for ecchymosis or deformity, palpation of bone attachment site, assessment for the presence of an intact tendon bundle, or appreciation of a palpable defect detected during strength testing.
For suspected proximal thigh tendon rupture, consider a plain AP radiograph of the pelvis to evaluate for fracture or avulsion fractures. If normal, patients may still have a partial or complete tendon rupture. Consider using ultrasound in the acute and subacute setting to assess for local hematoma, muscle tear, tendon bundle attachment, or complete rupture (Fig. 19–9).
Hamstring muscle tear and hematoma with intact tendon attachment. A. Short axis view showing inhomogeneity corresponding to partial muscle tear and central hypoechogenicity corresponding to the hematoma. B. Long axis view of same muscle showing intact hamstring tendon attachment at ischial tuberosity. (Used with permission from Ryan Petering, MD.)
A minimum of 6 weeks is needed for healing when partial rupture involving the muscles of the thigh occurs. Activity is permitted to the tolerance of pain; however, no sports or vigorous activity is allowed. Ambulation with crutches and a gradual return to activity is advised. Patients with complete ruptures should be made nonweight bearing, and referred. Surgical treatment is indicated for total or near-total hamstring muscle rupture. It is also considered in cases of bony avulsion of the ischial tuberosity when the avulsed fragment is displaced >2 cm. Surgical outcomes are superior when performed in the acute phase (less than 4 weeks from injury).46,48,49
The muscles of the thigh are invested in fascial sheaths. The fascial sheaths along the anterior and lateral aspect of the thigh are thinner just anterior to the iliotibial band. The patient may present to the ED with a complaint of a small palpable mass that appears when the quadriceps is contracted and disappears when the muscle is relaxed. Treatment is usually not necessary; however, if the symptoms warrant, surgical repair may be indicated.
Myositis Ossificans Traumatica
Myositis ossificans traumatica is a common condition in which a non-neoplastic ectopic calcium deposit is found in soft tissue at a site of prior trauma and hematoma. Myositis ossificans occurs as a complication after muscle contusion injuries in 9% to 17% of cases.35,50 This condition is commonly seen in the anterior thigh muscles after a moderate or severe contusion. The patient is usually a young athlete playing a contact sport.51 In most cases of myositis ossificans, the involvement is limited to the middle third of the thigh; however, in some it extends into the proximal third. Cases of myositis ossificans in the adductor muscles have also been reported. Myositis ossificans can also be congenital, occur after surgery, present as a complication of paraplegia or prolonged immobilization, or can be seen in the setting of serious disease such as clotting factor deficiencies. It can also be mistaken for osteosarcoma.50
Myositis ossificans is usually diagnosed 2 to 4 weeks after injury to the thigh. Palpation may reveal a firm and tender mass in the soft tissue. The patient may have limited range of motion due to pain or mass effect.
The radiograph usually shows evidence of irregularly shaped heterotopic bone within 2 to 4 weeks after an injury (Fig. 19–10). Three forms of myositis ossificans have been described: (1) a type with a stalked connection to the adjacent femur, (2) a periosteal type with continuity between the heterotopic bone and the adjacent femur, and (3) a broadbase type with a portion of the ectopic bone projecting into the quadriceps muscle.37
Myositis ossificans. (Image used with permission from Erik Foss, MD.)
The emergency physician should be aware of the preventive measures to avoid the development of myositis ossificans. The patient with a quadriceps contusion should be cautioned against early active use of the quadriceps and forceful passive flexion of the knee. Once present, myositis ossificans is usually not severely disabling, although some patients may require surgical excision due to pain once the bone has matured. Once the diagnosis is established, appropriate referral and follow-up are indicated.