A prolonged recovery or persistent symptoms should alert the treating physician to the possibility of complications, including myositis ossificans.8,20 Myositis ossificans typically results from moderate to severe contusions, which may present initially as a painful, indurated mass that later becomes quite firm. This mass may be seen on plain radiographs as early as 2 to 4 weeks following injury if the athlete complains of persistent pain or a palpable thigh mass (Figure 2).9
The risk of myositis ossificans increases in proportion to the severity of injury.18 Among US military academy members, the incidence of myositis ossificans following quadriceps contusions ranges from 9% to 20%.9,10 These masses often masquerade as a neoplasm that results in an unnecessary biopsy which reveals an “aggressive” lesion leading to an incorrect diagnosis of a soft-tissue sarcoma. MRI and/or computed tomography scanning may confirm the diagnosis of a benign process in these questionable cases as the lesion matures, with ossification demonstrated on both T1- and T2-weight imaging.21 Even in the presence of myositis ossificans, most patients regain full knee and hip motion and return to sports without residual weakness or pain.20 Very rarely, persistent symptoms and limitation of motion may warrant consideration for surgical excision of the symptomatic mass once it is considered mature, which generally occurs within 6 months to 1 year, in order to avoid the risk of recurrence resulting from the surgical trauma.9, 22
Mani-Babu and colleagues23 reported a case of a 14-year-old male football player who sustained a quadriceps contusion after a direct blow from an opponent’s helmet to the lateral thigh. Persistent pain and limitation of motion at 2 months follow-up prompted imaging studies that demonstrated myositis ossificans. The patient was treated with intravenous pamidronate (a bisphosphonate) twice over a 3-month period and demonstrated a full recovery within 5 months.
Acute compartment syndrome of the thigh has also been reported following severe quadriceps contusions, with the majority occurring in the anterior compartment.12,24-28 When injury from blunt trauma extends into and disrupts the muscular layer adjacent to the femur, vascular disruption can cause hematoma formation, muscle edema, and significant swelling, thereby increasing intracompartmental pressure. The relatively large volume of the anterior thigh compartment and lack of a rigid deep fascial envelope may be protective from the development of compartment syndrome compared to other sites.28 It can be difficult to distinguish a severe contusion from a compartment syndrome, as both can occur from the same mechanism and have similar presenting signs and symptoms. Signs of a compartment syndrome include pain out of proportion to the injury that is aggravated by passive stretch of the quadriceps muscles, an increasingly firm muscle compartment to palpation, and neurovascular deficits.29 Both acute compartment syndrome and a severe contusion may present with significant pain, inability to bear weight, tense swelling, tenderness to palpation, and pain with passive knee flexion.24 While the successful conservative treatment of athletes with acute compartment syndrome of the thigh has been reported, it is important to closely monitor the patient’s condition and consider intracompartmental pressure monitoring if the patient’s clinical condition deteriorates.12 An acute fasciotomy should be strongly considered when intracompartmental pressures are within 30 mm Hg of diastolic pressure.24-27 Fortunately, it is highly uncommon for thigh compartment pressure to rise to this level. Percutaneous compartment decompression using liposuction equipment or a large cannula has been described to decrease intracompartmental pressure, potentially expediting recovery and minimizing morbidity.18 Interestingly, reports of fasciotomies for acute thigh compartment syndrome following closed athletic injuries have not described necrotic or non-contractile muscle typical of an acute compartment syndrome, calling into question the need for fasciotomy following closed blunt athletic trauma to the thigh.18
Quadriceps Strain
Pathophysiology
Acute quadriceps strains occur during sudden forceful eccentric contraction of the extensor mechanism. Occasionally, in the absence of a clear mechanism, these injuries mistakenly appear as a contusion resulting from a direct blow to the thigh.30,31 The rectus femoris is the most frequently strained quadriceps muscle due, in part, to its superficial location and predominance of type II muscle fibers, which are more likely to be strained.11,32 Although classically described as occurring along the distal portion of the rectus femoris at the musculotendinous junction, quadriceps strains most commonly occur at the mid to proximal aspect of the rectus femoris.30,33 The quadriceps muscle complex crosses 2 joints and, as a result, is more predisposed to eccentric injury than mono-articular muscles.34 We have had a subset of complete myotendinous tears of the rectus femoris that occur in the plant leg of placekickers that result in significant disability.
