Evaluating and Managing Muscle Contusions and Myositis Ossificans
Christopher M. Larson, MD; Louis C. Almekinders, MD; Spero G. Karas, MD; William E. Garrett, MD, PhD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 30 - NO.2 - FEBRUARY 2021
In Brief: Muscle contusions almost always completely heal, but sometimes they give rise to hematomas or myositis ossificans. Warning signs of severe quadriceps contusion include marked decreased knee range of motion and a sympathetic knee effusion. Management consists of rest, cooling, compression, and elevation. Corticosteroids should be avoided, but nonsteroidal anti-inflammatory drugs may reduce edema and the risk of myositis ossificans. Rehabilitation protocols that include early flexion exercise can hasten recovery and decrease the likelihood of myositis ossificans. Asymptomatic myositis ossificans needs no treatment, but when it is associated with decreased range of motion, muscle atrophy, and continued pain, lesions may be excised after they mature.
Myositis ossificans traumatica, a benign lesion characterized by heterotopic ossification of muscle, has been recognized since the 18th century and most commonly affects individuals who sustain a severe muscle contusion from contact sports.1-4 It is important for the sports medicine physician to recognize injuries and situations that predispose patients to myositis ossificans, since the condition may cause lengthy disability.1,2,5,6
Although much has been written about myositis ossificans, the exact mechanism of onset remains unknown, and controversy about management and preventive measures persists.5-8 However, current findings are helpful in establishing a generalized treatment protocol.
Muscle contusions are caused by external blows—often during contact sports—that are sufficient to cause tissue damage and vascular disruption that can produce two types of injury.6,9 The first is intermuscular hematoma with septal or fascial sheath hemorrhage that is more likely to disperse and cause distal ecchymosis. The second is intramuscular hematoma, an injury that resolves more slowly and is associated with myositis ossificans and scar contracture.
Contusions and myositis ossificans. A blow to an extremity creates a compression wave that travels through soft tissue and causes damage primarily to the deep portion of muscle by crushing it against the adjacent bone. This phenomenon explains why the location of myositis ossificans is frequently the deep quadriceps (vastus intermedius) and brachialis muscles.4,6 Several authors5,7,8,10-13 have evaluated crush injuries to the quadriceps in humans and animals and found that, within 24 hours, extravasation of blood occurred primarily throughout the deep musculature and areas of acute inflammation. Bleeding was widely dispersed between and within muscle. Acute inflammation resulted in elimination of necrotic debris, and, by 1 week, hematoma and necrotic muscle had been replaced by granulation tissue with a dramatic increase in myoblastic activity.5,7,8,10-13 After 3 weeks, dystrophic calcium appeared and intramembranous bone formed in muscle that developed ossification.5,7,8 Although not yet definitive, one theory proposes that bone forms within repair tissue because of cell metaplasia (eg, fibroblasts) into osteoblasts.8 The trigger and actual existence of the signal for this transition are not known.
Mature myositis ossificans consists of a peripheral zone of lamellar bone, an osteoid middle zone, and a central proliferation of granulation and fibrous tissue.6-8 Often, the ossification formed will coalesce with the adjacent bone and then subsequently shrink, sometimes completely resolving.1,3,5-8 A study8 in sheep indicates that periosteal hyperplasia with appositional bone and ectopic bone formation are two separate entities that may result from contusions.
Mitigating factors. Although contusion alone can lead to ossification, forceful manipulation may also play a role. Michelsson et al7 immobilized rabbit hind legs for up to 5 weeks except for a daily 5-minute session of forceful mobilization. This treatment resulted in myositis ossificans in all 41 rabbits, and the radiographic and histologic findings were identical to those in postcontusion human muscle. Although these experimental injuries may resemble a severe muscle strain more than a contusion, they do show that forceful manipulation can provoke myositis ossificans.
Despite such a model, studies11,12 have also demonstrated that early mobilization accelerates muscle recovery after contusions. In a rat model, moderate muscle contusions can reduce the tetanic tension of muscle, decreasing it to 63% of normal after contusion within the first 24 hours, with a return to near-normal contraction at 24 days.11 When comparing postcontusion mobilization to immobilization in this model, hematoma and inflammatory reactions were more pronounced in the mobilized muscles.12,13 Two days after injury, a decrease in breaking strength and energy absorption was the same whether the muscle was immobilized or not, but, thereafter, mobilized muscle values returned to normal more rapidly than immobilized muscles. Histologic examination revealed that muscle regeneration was also more extensive and occurred more rapidly in the mobilized muscles.
Classifying Contusions and Myositis Ossificans
Contusions may be graded as mild, moderate, or severe. In general, if the range of motion in the adjacent joint is two thirds that of normal, the contusion is considered mild. One third to two thirds of normal is considered moderate, and less than one third is classified as severe.6 Quadriceps contusions have been well described according to the active range of knee motion measured 12 to 24 hours after injury: mild, >90°; moderate, 45° to 90°; and severe, <45°.1,2 Incidences of myositis ossificans vary according to the severity of the precipitating contusion, with severe contusions giving rise to myositis ossificans more often.1,2,5 Severe contusions have also been shown to result in greater disability and a longer time to full activity.1,2,5
Myositis ossificans has been classified according to its radiographic appearance as (1) connected to the adjacent bone by a stalk, (2) periosteal type with total continuity between the heterotopic bone and the adjacent bone, (3) or the broad-based type (intermediate between 1 and 2), with a portion of ectopic bone projecting into the quadriceps.1-3 The heterotopic bone without connection to the adjacent bone has been reported in humans but has not been seen in animal models of contusion and may be secondary to a muscle strain rather than a muscle contusion.14 This classification system, however, does not appear to predict prognosis.
Diagnosing the Condition
Clinical characteristics. The typical patients are athletes in their second or third decades of life who sustain a direct blow to the anterior thigh or upper arm. Swelling, significant pain, and decreased ability to bear weight or use the extremity follow, depending on the severity of the injury. Patients seen soon after injury may have a significantly decreased range of motion, swelling, warmth, and ecchymosis, while knee effusions may be present in more severe quadriceps injuries.1,2
If patients present after several days, they may have a palpable mass, but initial radiographs will be negative. Bone scintigraphy, magnetic resonance imaging (MRI), and ultrasonography have been reported to reveal myositis ossificans before it is visible on conventional plain radiographs, but these techniques' utility for early cases has yet to be confirmed.5,15-17 After 3 to 6 weeks, radiographs will reveal any heterotopic ossification, typically deep within the muscle, adjacent to the bone.1-3,5-7 Usually these patients will recover gradually with decreasing pain, increasing maturity of the ossification, and, finally, varying degrees of resorption of the myositis ossificans.1,2,5,6,18
Differential diagnosis. For a patient whose radiographs reveal heterotopic ossification (figure 1), the differential diagnosis should include benign lesions such as osteochondroma, osteomyelitis, fibrodysplasia (myositis) ossificans progressiva, and malignant lesions such as osteosarcoma, chondrosarcoma, and synovial cell sarcoma.2-4,6,18-22 Symptoms can help differentiate the disorders. Unlike myositis ossificans, osteochondromas have a medullary cavity continuous with the adjacent long bone. Patients with osteomyelitis may have constitutional symptoms (fever, chills, night sweats). Those with fibrodysplasia progressiva, an autosomal dominant disease, are usually diagnosed in childhood and have multiple heterotopic ossification areas associated with hypoplastic first metatarsal and first metacarpal bones.19,20,22,23
A history of trauma does not differentiate myositis ossificans from osteosarcoma, as 40% of patients with osteosarcomas have a history of trauma.3,6 Patients with myositis ossificans typically have decreasing pain and lesion size as the condition matures versus increasing pain and lesion size usually seen with malignant tumors. Radiographically, myositis ossificans has zones of dense mature bone at the periphery with central radiolucency, whereas malignant tumors exhibit the greatest maturity at the center of the lesion and greatest anaplasia at the periphery.4,6,22 Furthermore, myositis ossificans is most often diaphyseal in location compared with the classic metaphyseal location of osteogenic sarcoma. Biopsy may not be helpful, as the immature callus of the benign myositis ossificans lesion can resemble pseudomalignant type cells and lead to equivocal pathologic review.6,18 If any question remains, serial radiographs that reveal no change or resorption of the lesion will usually confirm the diagnosis.
Management for Contusions and Early Myositis Ossificans
Few large studies in humans1,2,5 have evaluated the efficacy of different treatment modalities for contusions and early myositis ossificans; however, some basic approaches are helpful.
Acute injury. Rest, cooling (with a cryocuff or ice bags), compression, and elevation are felt to be beneficial, while early aggressive range of motion and recurrent injury are reported to increase the rate of myositis ossificans.1,2,5,7,19 Studies in animals reveal development of myositis ossificans after forceful manipulation, but they also support the use of early mobilization to accelerate muscle regeneration.
Large human studies1,2,5 have shown that the rates of myositis ossificans increase with injury severity. The incidence of myositis ossificans ranges from 0% to 9% for mild contusions to 17% to 72% for moderate-to-severe contusions.1,2,5 For recurrent contusions, Jackson and Feagin1 reported a 100% rate of myositis ossificans after quadriceps reinjury, and Ryan et al2 noted the condition in 54% to 64% of patients who had a history of contusion.
Postinjury protocols. Jackson and Feagin1 reported a 20% incidence of myositis ossificans among West Point cadets, and Rothwell5 reported a 17% incidence of myositis ossificans when both groups used a specific postinjury protocol. Their protocols consisted of three phases (limiting hemorrhage, restoration of motion, and functional rehabilitation) and focused on achieving extension early on. A subsequent study2 of 115 West Point cadets employed a modified postinjury protocol that focused on early flexion instead of extension. This study revealed a 9% rate of myositis ossificans and decreases in disability time of 66% for moderate contusions and 71% for severe contusions compared with results of earlier studies.1 The protocol did not use hematoma aspiration or anti-inflammatory medications. No patient who developed myositis ossificans had late symptoms or a disorder-related surgical procedure done, and all returned to preinjury levels of sporting activity.
The use of ultrasound after contusion has not been studied. We feel that any modality that produces heat should probably be avoided in the early treatment of muscle contusions.
Drugs and irradiation. The use of nonsteroidal anti-inflammatory drugs (NSAIDs), low-dose irradiation, or steroids has not been extensively studied in myositis ossificans. Both NSAIDs and single-dose irradiation have been shown to be very effective in preventing the formation or recurrence of heterotopic ossification after total hip arthroplasty and excision of heterotopic ossification.24-27
NSAIDs (indomethacin and naproxen sodium; the only drugs well studied) are effective if used for 2 to 6 weeks, but shorter-term usage has not been shown effective in human studies.24-27 Louis Almekinders and Rahusen (oral communications), however, found that NSAIDs given immediately after contusion compared with NSAIDs given 24 hours postinjury were more effective in decreasing edema in a mouse contusion model. They also found that acetaminophen, although not as effective as NSAIDs, was also effective in this model. They hypothesized that the analgesic effect may stimulate faster regaining of motion and prevent and possibly decrease edema. Continuous passive motion has not been shown to reduce disability time or the incidence of myositis ossificans.2
Steroids. Recently, corticosteroids or single-dose anabolic steroids have been reported effective for healing muscle contusions in a rat model.10 Corticosteroids produced healing for several days after injury, but at 1 and 2 weeks postinjury, corticosteroid-treated muscles had degenerated and exhibited disorganized muscle fiber architecture. Anabolic steroid-treated muscles, however, were significantly stronger than control muscles at 2 weeks after injury, and the authors concluded that anabolic steroids may aid healing in severe muscle contusions. Currently, the role of steroids in human muscle repair remains unclear and will require further research.
Late sequelae. Myositis ossificans development does not correlate with late functional disability in most patients.1-3,5,6,18 If myositis ossificans persists with continued muscle atrophy, joint limitations, and pain, excision is recommended only after radiographs show that the lesion is mature,1-3,6,18,28 typically 6 to 12 months after injury.1-3,6,18,28 Early removal has been associated with exacerbation of the condition, prolonged disability, and recurrence.3,6,9,18 Even with late removal of symptomatic myositis ossificans, recurrence rates of up to 67% have been reported.3,28 Bone scans may be helpful in evaluating lesion maturity.3,29 Authors30,31 have recommended that patients who sustain significant contusions, whether or not myositis ossificans develops, should wear padding for 3 to 6 months to avoid reinjury, which increases the risk of developing myositis ossificans.1-3,5,8
Three-Step Management for Myositis Ossificans
Because of the low rates of myositis ossificans and reduced recovery times observed by Ryan et al,2 we prefer to use a similar three-phase protocol.
Phase 1: pain control. For athletes with muscle contusions, we employ the standard rest, compression, cooling, and elevation algorithm for 24 to 48 hours regardless of injury severity. Cooling and compression can be done with ice bags and compressive bandages (figure 2), or with commercially available cryocuff wraps. Healthcare providers should avoid or limit direct application of ice over superficial nerves to avoid potential injury.
We do not routinely perform aspirations, and although we do not routinely prescribe NSAIDs for mild contusions, we do recommend 2 to 6 weeks of naproxen (750 mg qd) or indomethacin (50 mg bid) for moderate and severe contusions. Patients unable to take NSAIDs may benefit from alternative analgesics such as acetaminophen. Occasionally, patients with severe contusions (eg, <45° knee range of motion) may require hospitalization for pain control. We recommend positioning the extremity so that the injured muscle is held out to length without additional pain (eg, hip and knee flexed for a quadriceps contusion, elbow extended to tolerance for a brachialis contusion).
Phase 2: restoring mobility. When swelling has stabilized and patients are pain free at rest, we begin gentle active and passive range-of-motion exercises and focus on regaining flexion for quadriceps and extension for brachialis contusions. For leg contusions, patients can bear weight to tolerance. We continue compression, and, when patients are comfortable enough and have good muscle control, they advance to the functional rehabilitation phase. At this point, we focus on low-intensity exercises (eg, walking, cycling, jogging for quadriceps injury) to restore normal movement patterns and avoid reinjury. If patients experience significant pain or reinjury, they revert to the previous phase.
Phase 3: functional rehabilitation. When patients regain nearly full extremity range of motion and achieve near-normal strength, they return to sport-specific activities and gradually return to full activity. For example, throwing athletes with brachialis contusions return to light throwing after return of full range of motion, strength, and resolution of muscle tenderness. If throwing is not painful, patients can increase velocity to as much as they can tolerate. We also recommend padding the injured extremity for 3 to 6 months postinjury. If a firm mass develops, we recommend plain radiographs after 3 to 6 weeks to confirm myositis ossificans and rule out another diagnosis.
Rehabilitation is not altered if myositis ossificans develops. If the disorder persists but remains asymptomatic, as is most common, no additional treatment is needed. If the mass is symptomatic with continued muscle atrophy, limited joint motion, and pain after conservative treatment, we recommend excision after bone scans confirm that the lesion is mature (usually 6 to 12 months). After excision, we recommend NSAIDs (naproxen or indomethacin as noted in phase 1) for 6 weeks. These patients should follow the three-step recovery protocol described above.
The Road Ahead
Although the athlete who sustains a contusion almost always return to preinjury levels of activity, a well-designed management protocol may significantly hasten recovery and lower the incidence of myositis ossificans. If myositis ossificans develops, it usually follows a severe contusion and has minimal clinical sequelae. If symptoms occur late in the course, myositis ossificans can be challenging, with significant recurrence rates after excision. Well-designed studies are needed to evaluate the effect of different treatment regimens on recovery time and to assess the effectiveness of NSAIDs or other agents in reducing the incidence or recurrence of myositis ossificans.
Dr Larson is a staff physician at the Minneapolis Sports Medicine Center in Edina, Minnesota. Drs Almekinders, Karas, and Garrett are physicians in the department of orthopedics at the University of North Carolina at Chapel Hill. Address correspondence to Christopher M. Larson, MD, 5330 France Ave, Suite 101, Edina, MN 55410; e-mail to [email protected].