MYOSITIS OSSIFICANS

Dr.k.prashanth kumarS V S Medical College Hospital

MAHABUBNAGAR

MYOSITIS OSSIFICANS• Acquired development of non neoplastic heterotopic ossification

within soft tissues

• Most often in response to localized trauma

• Although the process most commonly develops within skeletal muscle, the term itself is a misnomer, because nonmuscular tissue may be involved, and inflammation is rare.

• Adolescents & young adults, predominantly men, are affected most frequently, although it has been reported in infancy as well

ECTOPIC OSSIFICATIONEctopic ossification – formation of pathologic bone

• Common term for – Heterotopic Ossification (HO)– Myositis Ossificans (MO) – Periarticular calcification

• HO & MO - deposition of mature lamellar new bone - share radiologic & histologic features

• HO develops in non osseous tissue while MO forms in damaged or inflamed muscle

• Periarticular calci. denotes deposition of Cal. Pyrophos. in collateral lig. & joint capsule - radiologically it does not display trabecular organisation

Anne M Casavant, Hill Hastings II, Indianapolis, Journal of Hand Therapy – 2006; 19:255 -67

Difference between normal bone & ectopic bone

Normal bone : has periosteal covering - outer fibrous layer - inner vascular cambium layer

Ectopic bone: does not have periosteal covering

ETOLIOGY

PRECIPITATING FACTORS - single or repetitive trauma (70%) - severe thermal injury- neurologic conditions - posttraumatic paraplegia - brain injury- orthopaedic operations – THR

GENETIC & DEVELOPMENTAL FORMS - fibrodysplasia ossificans progressiva- progressive osseous heteroplasia- pseudomalignant heterotopic ossification- Albright hereditary osteodystrophy,- parosteal fasciitis

PATHOGENESIS

• Following cellular injury - degeneration and necrosis of the tissue followed by histiocytic invasion during removal of necrotic debris

• Within 3 or 4 days, fibroblasts from the endomysium invade the damaged area and primitive mesenchymal cells proliferate within the injured connective tissue

• The fibroblasts and mesenchymal cells then give rise to osteoid and

chondroid tissue as early as 4 to 5 days after injury.

• As the process of osteoid & mineralisation evolves, it progresses inward towards the centre.

PATHOGENESIS

• The reactive bone is gradually replaced by mature lamellar bone

• This centripetal pattern of ossification and maturation develops during the second week to second month

• With passage of time mass is well demarcated & decreases in volume and in some it may completely resolve

• Reduced collagen degradation in polytraumas with traumatic brain injury causes enhanced osteogenesis

Journal of NeurotraumaVolume 23, No 5, 2006 Jonas Andermehr, Andreas Elsner, Axel Jubel et al.,

HIGH RISK POPULATION• idiopathic skeletal hyperostosis

• ankylosing spondylitis

• preexisting ipsilateral or contralateral heterotopic ossification

• hypertrophic osteoarthrosis

• post-traumatic arthritis

• Postoperative

• closed head injury, stroke, and prolonged immobilization

Common sites of HO in Elbow

Collateral LigMedialLateral

Posterior HOOlecranon ExtensionOlecranon FossaHumeroulnar bridge

anterior

Humeroradial HORadioulnar synostosis

CLINICAL FEATURES

• Typically begin approximately 1 to 3 weeks after an injury

• Localized pain and a palpable mass.

• Increased warmth, swelling

• Progressive loss of ROM - hallmark sign

• A low-grade fever

• mildly elevated ESR

CLINICAL FEATURES

• Limb involvement - quadriceps, hip

- brachialis although virtually any region of the body can be affected

• increase in the firmness of the lesion

• decrease in pain occur over an 8 to 12 wk period

• entrapment of the nerves (ulnar, median, radial)

• development of varying degrees of contracture of the affected part.

RADIOGRAPHIC FEATURESEARLY PLAIN RADIOGRAPHS

- non calcified mass in the soft tissues

Within 2 to 4 weeks after the injury- floccular calcifications begin to appear within the mass- if the cambium layer of the periosteum was involved in the initial injury, a periosteal reaction of the underlying bone

Over a 6 to 8 wk period - serial x rays at 1 to 2 wk intervals - - peripheral osseous maturation of the lesion, with - central lucent zone and a lucent line separating it from the underlying cortex , distinguishing from an extraosseous sarcoma

After 5 to 6 months- mature bone is evident, and the lesion may show a decrease in overall size

RADIOGRAPHIC FEATURES• CT scan

- delineats the zonal maturation and cortical separation when the diagnosis is unclear

• Other imaging modalities - bone scintigraphy - ultrasound - MRI - leukocyte scanning, and angiography, particularly in early lesions or in difficult cases

In patients with a typical history of trauma and localized findings with x ray evidence of progressive peripheral osseous maturation, the use of these other

imaging modalities is infrequently required.

HISTOPATHOLOGY

The hallmark is the zonal phenomenon (Ackerman)

• CENTRAL (inner) ZONE - undifferentiated cells and atypical mytotic figures, which may be impossible to distinguish from a sarcoma

• AN ADJACENT (middle) ZONE - well-oriented osteoid formation in a non-neoplastic stroma

• PERIPHERAL (outer) ZONE - well-oriented lamellar bone, clearly demarcated from the surrounding tissue

Ackerman LV. Extra-osseous localized non-neoplastic bone and cartilage formation. Journal Bone Joint Surg Am 1958;40:279.

• The origin of the bone-forming cells in myositis ossificans remains unknown. Recent investigations into the role of extraskeletal osteogenic precursor cells, and the local factors that induce them, may provide insights into the formation of MO

• Origins of ectopic bone formation in myositis ossificans, and in other disorders characterized by the formation of heterotopic ossification .

Illes T, Dubousset J, Szendroi M, et al. Characterization of bone-forming cells in post-traumatic myositis ossificans by lectins. Pathol Res Pract 1992;188:172

CLASSIFICATION• MO secondary to Trauma

- Blunt- Thermal- Penetrating- Iatrogenic

• MO assoc. with neurological disorders- Traumatic paraplegia- Traumatic quadriplegia- Closed Head injury

• Localised MO of unknown origin

• Myositis Ossificans Progressiva

CLASSIFICATION OF HOClass I - no functional ROM limitation

CLASS II - limitation of functionl ROMsubdivided into 3 categories - which planeflexion/extension pronation/supination

CLASS III - ankylosis of elbow - limiting flexion/extensionpronation/supinationsubdivided in which plane it is ankylosed

Hastings H, Graham TJ, Classification and Treatment of HO about elbow and forearm. Hand clinic. 1994;10:417-37

CLASSIFICATION(size of the mass)

Ilahi, Omer A, MD; Strausser, David W, MD; Gabel, Gerard T, MDDepartment of Orthopedic Surgery, Baylor College of Medicine, Houston, Tex

Angle subtended by the largest area of the ectopic fragment on lateral radiograph measuring from the centre of rotation

GRADE I < 30

GRADE II 30 - 60

GRADE III > 60

GRADE IVUlnohumeral ankylosis on any x ray view

MYOSITIS OSSIFICANS PROGRESSIVA(Fibrodysplasia ossificans progressiva)

“stone man syndrome”

• Autosomal dominant connective tissue disorder

• muscle tissue and connective tissue –tendons & lig.gradually replaced by bone (ossified), extra-skeletal or heterotopic bone that constrains movement

• Malformed big toes - single phalanx

• No cure

• Usually die early - malnutrition & recurrent infections

MANAGEMENT

• PHYSICAL THERAPY

• SURGICAL MANAGEMENT

MANAGEMENTPrevention of heterotopic ossification at the site of initial injury would be ideal.

Variable depending on the stage of development

NSAIDs - diminish symptomatology in the early stages.

• Hughston et al. - strict rest of the affected part - splinting, would allow for more complete resorption of hematoma and discourage formation of heterotopic bone

• Thorndike - advocated a combination of rest, icing, compression bandaging, and avoidance of massage therapy

• Ryan et al. - advocated that the position of splinting of the affected muscle should be in tension (e.g., flexion for quadriceps contusion)

However, there is presently no clear evidence that such measures prevent the development of myositis ossificans, or modify its severity.

• Single low-dose radiation therapy,

• Indomethacin, aspirins

• Low Energy Extracorporeal Shockwave Therapy for the Treatment of Myositis Ossificans in a Case of Cerebro Vascular Accident

• Early passive mobilization are the preventive treatment modalities suggested by various studies

Bibhuti Sarkar1 , S S Rau2 1 Physiotherapist, 2 Asst. Professor (Physiotherapy), National Institute for the Orthopaedically Handicapped (N.I.O.H), B. T. Road, Bonhooghly, Kolkata

Indian Journal of Physiotherapy & Occupational Therapy. April-June 2013, Vol. 7, No. 2

THERAPY PROGRAMME(after injury / surgery)

• Acute & oedematous phase (first 2 wks)

• Inflammatory phase (2 - 6 wks)

• Fibrotic phase (6 - 12 wks)

• Late phase (3 - 6 months)

THERAPY PROGRAMME(after injury / surgery)

• Acute & oedematous phase (first 2 wks)- oedema controlling measures - inflamm.- ice, compressive dressings, pain management- active ROM within the parameters & stability (otherwise muscles quickly lose strength)

• Inflammatory phase (2 - 6 wks)- prolific unorganised scar tissue present(very active but malleable and deformable) & responds to therapy- self passive stretching & serial static /dynamic splinting 4 – 6 times a day for 30 mts- when HO is revealed on x ray - at 4 to 6wks, therapy contd. to maximise ROM -

THERAPY PROGRAMME(after injury / surgery)

• Fibrotic phase (6 - 12 wks)- scar tissur fully formed but is reorganising & responds to motion & stress- fractures if any would have healed by this time- guarded increase in the intensity of exercise- day splinting in the position of max stretching- resistive exercises in the splint will maximise ROM gains

• Late phase (3 - 6 months)- scarring is organised (fibrous tissue)

- splinting to recapture ROM contd. as long as gains- splinting is weaned off & home strengthening prog . to regain muscle strength

INDICATIONS FOR SURGICAL INTERVENTION:

• Mere presence of HO or limitation of elbow motion does not warrant surgical excision

• Indicated only when the limited elbow ROM prevents functional use of the affected extremity

• Performed only when the HO matures after 6 – 12 months

Neglected posterior dislocation of elbow with HO

2 wks after Total Elbow Arthroplasty for post traumatic stiff elbow

Anterior HO 6 months after surgery has not progressed from the initial size

Inverted “V” Osteotomy Excision Arthroplasty for Bony Ankylosis Elbow

28 yr old lady with MO & bony ankylosis80 months P O follow up

,Coimbatore

CONCLUSION

• It is a complex process• Extent of formation directly related to severity

of injury• Neural axis injuries & thermal injuries are

predisposing conditions• Why certain cells differentiate into bone and

not scar remains unclear• Formation HO begins in the first 2 wks of

injury

CONCLUSION

• Ossification progresses over next several months

• HO matures over period of 6 – 12 months• Mild degree cases resolve spontaneously• Comprehensive physical therapy prog. may

restore useful ROM• Surgery is indicated only when useful ROM

could not be achieved by therapy

THANK YOU