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Myositis Ossificans
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Contents
Other Names
- Myositis Ossificans Traumatica
- Myositis Ossificans (MO)
- Myositis (fibrous) ossificans progressive
- Traumatic circumscripta
- MO circumscripta
- Fibrodyspolasia ossificans progressive
- Rider’s bone
- Shooter’s bone
Background
- This page refers to Myositis Ossificans (MO)
- This can be defined as a benign, solitary, frequently self-limiting, ossifying soft-tissue mass found in skeletal muscle often encountered in the active sporting population
- Although there are multiple types, this review will primarily focus the traumatic form seen in Athletes
Definition
- WHO subtypes
- Traumatic
- Atraumatic, sometimes termed pseudomalignant
- MO associated with paraplegia
- Progressive MO
History
- In 1905, Jones and Morgan questioned whether MO is a pure inflammatory condition[1]
- In 1913, Coley described the challenges in distinguishing it from malignancy[2]
Epidemiology
- Incidence is somewhat challenging because it may occur with or without trauma
- Traumatic MO represents 60-75% of all cases[3]
- Simon et al estimated that muscle trauma represents 10% - 55% of athletic lesions, but not all muscle trauma leads to MO[4]
- Up to 40% of cases can be insidious without clear history of trauma
- Demographics[5]
- More common in males than females
- Most often in 20s, 30s
- Location
- 9% - 20% of Quadriceps Femoris injuries result in MO[6]
Pathophysiology
- General
- Internal lesions: Strains, pulls and tears
- External lesions: direct trauma or impact
- Inadequate healing of muscle lesions can result in various complications including
- Delayed healing time
- Encysted hematoma
- Fibrosis
- Leads can all lead to myositis ossificans (MO)
- Precise pathophysiology is poorly understood, several proposed etiologies include
- Inappropriate differentiation of fibroblasts into osteoblasts, chondroblasts following trauma
- This is primarily due to bone morphogenic protein (BMP-2, BMP-4) and transforming growth factor (TGF)
- Proinflammatory prostaglandin synthesis occurs following muscle damage can contribute
- In the case of hematoma formation, subsequent necrosis and hemorrhage, followed by reparative fibroblastic and vascular proliferation
- Description
- Liquefaction, formation of nonspecific sheets of cells in damaged muscle following injury
- Cytokines recruit further inflammatory cells, macrophages into necrotic tissue
- Mediators encourage the formation of heterotopic bone
- Bone is laid down from outside to inside pattern (distinguishing it from neoplastic process)
- Natural history
- Early stage: occurs within first 4 weeks of injury, calcifications can be seen on xray
- Intermediate stage: between weeks 4 and 8
- Mature stage: 8 weeks onward, potentially for months, marked calcifications visible on xray
- Location
- Most commonly along diaphysis of long bones with larger muscle groups
- Includes Brachialis, Quadriceps Femoris, Adductor Muscle Group
- Can be challenging to distinguish from other lesions, namely myosarcomas
Other Locations
- "Rider's Bone"
- Occurs in the adductor muscle group among equestrian sports
- "Shooter's Bone"
- Occurs in the deltoid muscle
- Occurs in the soleus muscle among ballet dancers
Associated Conditions
Risk Factors
- For Quad MO
- Quadriceps Contusion with knee flexion < 120°
- Prior history of quadriceps contusion
- Sympathetic knee effusion
- Muscle injury with a delay of treatment of more than 3 days
- Sports
- Football
- Soccer
Differential Diagnosis
Differential Diagnosis Thigh Pain
- Fractures
- Muscle and Tendon
- Neurological
- Other
Clinical Features
- History
- Athletes will typically recall a specific injury or traumatic event
- Often treated for muscle strain or contusion and treated conservatively
- If pain or symptoms persist longer than anticipated, should suspect MO
- Will report localized pain, joint stiffness
- Will have difficult using muscle group, e.g. weight bearing if quad affected
- Physical Exam
- Pain and tenderness at site of injury
- Careful evaluation for any evidence of neurovascular compromise
- Special Tests
Evaluation
Radiographs
- Standard initial imaging modality
- Not ordered in the case of most suspected uncomplicated muscle injuries
- Can rule out fracture
- Findings
- 2-4 weeks: can see faint radiopacities or periosteal reactions
- 4-8 weeks: sharply well-circumscribed mass with a peripheral radiopaque rim, radiolucent center
- 8 weeks and on: becomes more radiopaque, well defined with radiolucent center
- 6-12 months: lesion may spontaneously regress slightly, appear smaller
- Li et al describes 3 separate radiographic appearances[7]
- A) Periosteal, flat MO formation occurs adjacent to the long-bone shaft, damaging the periosteum
- B) Stalk, where MO formation is attached to the long-bone shaft
- C) Intramuscular disseminated, where intramuscular MO formation occurs without periosteal disruption
CT
- May be useful early on
- Can detect calcifications that may not be detectable on radiographs initially
- Greatest utility late-to-early-stage to intermediate-stages
- Where classic zonal arrangement may be detected before the lesions become apparent on plain radiographs
- Findings[8]
- 2-4 weeks: soft tissue edema, mass, with or without calficiations
- 4-8 weeks: mineralization with low attenuation center
- 8 weeks and on: more diffuse ossification pattern
MRI
- General
- Often considered gold standard for soft tissue masses
- May not demonstrate early calcifications well
- Contrast is not typically required
- Findings
- 2-4 weeks: Hematoma which is isodense (T1), hyperintense (T2)
- 4-8 weeks: Isointense/hypointense signal peripherally and centrally compared to surrounding skeletal muscle
- 8 weeks and on: well defined mass, isodense to all fat sequences, resolution of surrounding edema
Ultrasound
- General
- Helpful to distinguish between solid and fluid filled cystic structures
- Abate et al suggests US is most suitable modality for MO due to low cost, ease of performance and favorable safety profile[3]
- Findings
- 2-4 weeks: Increased power Doppler signal with hyperechoic outer layer
- 4-8 weeks: Increased power Doppler signal with increased peripheral hyperechogenicity
- 8 weeks and on: Little to no power Doppler signal with more evident peripheral layer, hyperechogenicity
Laboratory
- No clear diagnostic test
- Acute phase
- CRP, ESR elevated
- Alkaline Phosphatase
- Begins to elevate around 3 weeks following acute injury
- Peak around week 10, return to baseline at week 18
- Can vary from 1.3x to 13.4x normal
- Nonspecific to MO, however trending to ensure they return to baseline may help exclude neuplastic process
- Creatinine Phosphokinase
- Role is not clearly defined in MO
Classification
Radiographic Stages of Myositis Ossificans
- Early (0-4 weeks)
- X-ray: Normal or faint calcification
- CT: Soft tissue edema
- MRI: Isodense on T1; hyperintense on T2
- US: Increased power Doppler signal with hyperechoic outer layer
- Intermediate (4-8 weeks)
- X-ray: Peripheral calcified rim, central lucency
- CT: Peripheral mineralization with low attenuated center
- MRI: Iso/hypodense to adjacent skeletal muscle on all images
- US: Increased power Doppler signal with increased peripheral hyperechogenicity
- Mature (>8 weeks)
- X-ray: Diffuse soft tissue calcification
- CT: Diffuse ossification pattern
- MRI: Well-defined mass, isodense to fat on all images
- US: Little to no power Doppler signal with more evident peripheral layer, hyperechogenicity
Management
Prognosis
- General
- Self limited with most athletes able to return to sport
- Surgical management
- Orava (2017) found 30/32 patients were able to return to preinjury level of competition[9]
Nonoperative
- General
- First line approach in virtually all cases
- Goal is to minimize symptoms, restore function and range of motion
- Initial management
- Relative rest
- Ice Therapy or Cryotherapy can reduce blood flow to injury by up to 50% (need citation)
- Brief period of immobilization, compression may reduce risk or size of hematoma formation
- NSAIDS
- Consider avoiding in first 1-3 days due to antiplatelet effects
- Then use of NSAIDs for 1-2 weeks is recommended
- Acetaminophen
- Recommended by some experts for pain control
- Physical Therapy
- Avoid aggressive rehab early on to prevent exacerbation of symptoms
- Can begin gentle range of motion early
- Role of static stretching in prevention or development of MO is not well defined
- Extracorporeal Shockwave Therapy (ECSWT)
- One case report demonstrated full return to sport at 16 weeks[10]
- Aspiration of hematoma
- Case series among Vanderbilt football players demonstrated benefit of aspiration for recovery, return to sport (need citation)
- No clear guidelines on when to utilize this procedure
- Bisphosphonates
- Suppress bone turnover, slow down minieralize process
- One case report describing an athlete receiving two doses of IV Pamidronate was associated with improvement in radiograph and clinical findings[11]
- Note should not be used in premenopausal women
Operative
- Indications
- Not clearly established
- Most lesions will regress when mature and become asymptomatic
- Failure of conservative therapy by at least 6 months
Rehab and Return to Play
Rehabilitation
- No clear guidelines for rehabilitation
- Should not begin gradual progressive exercise or physical therapy until pain free range of motion
Return to Play
- No clear guidelines for RTP
- General
- Symptoms start to subside between weeks 6-8
- Competitive return to sport typically occurs between 4 and 6 months
- Simon et al[4]
- Found 90% of patients returned to light physical activity at 3 months
- 90% of athletes returned to pre-injury level of sport at 6 months
- 100% returned to sport by 1 year
Complications
- Chronic pain
- Inability to return to sport
See Also
References
- ↑ Jones R, Morgan D. On osseous formations in muscle due to injury (traumatic myositis ossificans). Archive of the Roentgen. 1905; 9:245.
- ↑ Coley WB. I.Myositis ossificans traumatica: a report of three cases illustrating the difficulties of diagnosis from sarcoma. Ann. Surg. 1913; 57:305Y37.
- ↑ 3.0 3.1 Abate M, Salini V, Rimondi E, et al. Post traumatic myositis ossificans: sonographic findings. J. Clin. Ultrasound. 2011; 39:135Y40.
- ↑ 4.0 4.1 Simon T, Guillodo Y, Madouas G, Saraux A. Myositis ossificans traumatica (circumscripta) and return to sport: a retrospective series of 19 cases. Joint Bone Spine. 2016; 83:416Y20.
- ↑ Ackerman LV. Extra-osseous localized non-neoplastic bone and cartilage formation (so-called myositis ossificans): clinical and pathological confusion with malignant neoplasms. J. Bone Joint Surg. Am. 1958; 40:279Y98.
- ↑ Ngai A. Post-traumatic myositis ossificans. In: Roger B, Guermazi A, Skaf A, editors. Muscle Injuries in Sport Athletes. Sports and Traumatology. Springer. New York (NY): 2017.
- ↑ Li W-T, Horng S-Y, Chien H-F. Abdominis rectus intramuscular myositis ossificans. Formosan Journal of Surgery. 2016; 49:20Y6.
- ↑ Kransdorf MJ, Meis JM, Jelinek JS. Myositis ossificans: MR appearance with radiologic-pathologic correlation. AJR Am. J. Roentgenol. 1991; 157:1243Y8.
- ↑ Orava S, Sinikumpu JJ, Sarimo J, et al. Surgical excision of symptomatic mature posttraumatic myositis ossificans: characteristics and outcomes in 32 athletes. Knee Surg. Sports Traumatol. Arthrosc. 2017; 25:3961Y8.
- ↑ Ngai A. Post-traumatic myositis ossificans. In: Roger B, Guermazi A, Skaf A, editors. Muscle Injuries in Sport Athletes. Sports and Traumatology. Springer. New York (NY): 2017
- ↑ Mani-Babu S, Wolman R, Keen R. Quadriceps traumatic myositis ossificans in a football player: management with intravenous pamidronate. Clin. J. Sport Med. 2014; 24:e56Y8.