View
974
Download
12
Embed Size (px)
DESCRIPTION
Citation preview
Myositis Ossificans
extra-osseous non neoplastic growth of new bone Misnomer
Heterotopic ossification
not always inflammatory
within extra-skeletal soft tissues – mainly in connective tissue than muscle
Ectopic Calcification ?!!Deposition of radio dense
Calcium PhosphateDifference in mineral phaseNo true bone matrix is formed Eg:- Hyper/Hypoparathyroidism,
Renal failure, Following TB, Calcific Supraspinatus Tendinopathy,
Scleroderma, Dermatomyositis
Diffuse cutaneous, subcutaneous and muscular calcification:
Calcinosis universalis in
Dermatomyositis
Types Myositis ossificans
circumscripta /traumatica
fibrodysplasia ossificans progressiva (FOP)
Myositis ossificans circumscripta /traumatica
In response to soft tissue injury:- blunt trauma, stab wound, fracture/dislocation, surgical incision (THR)
Systemic Conditions:- Head injury,Spinal cord injuryTetanus, Burns
Without known injury:-
Nondocumented trauma,
Repeated small mechanical injuries(blunt trauma in horse riders)
Nonmechanical injuries caused by ischemia or inflammation.
Increased risk in patients with Diffuse Idiopathic Skeletal Hyperostosis (DISH) and Paget’s Disease
Pathophysiology
BMP stimulate primitive stem cells in soft tissues to form osteoblasts
Organization of Haematoma
Fibroblastic hypoplasia
Osteoid formation
Radiographic evidence in 6-8 weeks
The lesion begins to calcify at the periphery and works toward the center (Reverse in Osteosarcoma)
Histopath- 4 distinct zones:the central undifferentiated zone- mitotically
active the surrounding zone of immature osteoid
formation – less activezone with new bone – osteoblast & fibrous
tissue with trabecular organizationPeripheral zone of fibrous tissue
At least 10 days are required following onset of symptoms for these zones to become apparent.
drug abusers elbow ?!!
Paraspinal
most commonly in the second and third decade
Areas commonly affected - elbow, thigh, buttocks, shoulder and calf ., erector spinae, pectoralis muscles(Quadriceps and brachialis - most affected.)
Majority –asymptomatic; may cause pain/ loss of ROM
presents as a rapid enlargement and significant pain one to two weeks after injury.
Swelling and warmth at the site
Hypercalcemia- contributing factor
Increased ESR and serum alkaline phosphatase.
TreatmentWatchful inactivityRest and gentle stretching.
Surgery if persistent pain – excised in toto in mature cases
Risk of recurrence +
If left alone, the mass will shrink in size
Treatmentshould not continue to play sports or use the
affected muscle.
Avoid Heat and massage. Reinjury to the same area, returning to activity too
early, or initial passive forceful stretching can lengthen recovery.
Prophylaxis: NSAIDS(Indomethacin), low dose radiation
Heterotopic Ossification Osteosarcoma
Site: Diaphysis MetaphysisPeripheral rimming Ossification center
(can mimic necrotic tr) to periphery Improvement in pain over Pain worsens with time and
rest timeBiopsy:Zone phenomenon Undiff tissue- viable muscle
fibres similar to central intact cortex zone
Myositis Ossificans Progressiva / Fibrodysplasia Ossificans Progressiva
rare autosomal dominant disorder skeletal malformation and progressive, disabling
heterotopic osteogenesis.
fibrosing and ossification of muscle, tendon and ligaments of multiple sites often in the upper extremities and back that is disabling and ultimately fatal
Nine-year-old Mexican girl with Fibrodysplasia Ossificans Progressiva (FOP).
Chromosome 2q23-24 Heterozygous mutation (617G®R206H) in the
glycine-serine (GS) domain of the
Activin A receptor type I (ACVR1) gene, a bone morphogenic protein (BMP) type I receptor
Incidence 1in 2 millionAge: Average 5 yrs (Fetus-25 yrs)Their offspring have a 50% probability of
inheriting the condition.
painful lumps and stiffness in the adjoining joint. Lumps decrease in a few weeks, but joint
mobility reduction persists.
Exacerbating factors for ossifications at new sites
minor trauma, venipuncture,
biopsy of lumps, IM injections,
dental treatments, and excision of masses.
Most common sites:- sternocleidomastoid, paraspinal muscles, the masticatory muscles, shoulder and pelvic girdle muscles.
Spared are the abdominal muscles, extraocular muscles, muscles of facial expression, diaphragm, larynx and tongue muscles.
Ossification progresses from proximal to distal
and cranial to caudal.
C/FDigits: Short hallux in valgus with synostosis
short thumbs , ClinodactylyFibrous Tissues: Swelling in aponeuroses,
fasciae, and tendons- ossification in muscles and fibrous tissues, most prominent in the neck dorsal trunk and
proximal extremities (The sternocleidomastoid muscle is commonly affected.)
Kyphoscoliosis: Restricted shoulder and pelvic girdle movements
LabHemogram, ESR, S.Ca, P:- WNLECG findings may be abnormalspirometry :-restrictive pattern, reflective of chest
wall involvement.
Plain radiography of FOP
Short metacarpals and metatarsals Phalangeal synostosis (eg, monophalangeal great
toe) Vertebral fusions, vertebral anomalies (i.e., small
bodies), pedicle thickening Thick, short femoral neck Variations in bone maturation sequence Increased incidence of enchondromas
TreatmentOnce diagnosis is established, usually clinically,
any surgical biopsy is contraindicated in FOP.
No established medical therapy exists.
Pain medications
supportive measures -gentle occupational and/or physical therapy.
Prevention is better!!
avoid falling or getting bruises
avoid IM injections since these can cause bone to grow.
Never stretch their joints outside of their normal ROM.
Flare-ups can occur spontaneously, even perfect preventive care cannot guarantee the absence of bone growths.
The mainstay of diagnosis is bilateral great toe anomaly present from birth, reported in 79 to 100% of patients
microdactyly of both halluces due to a single phalanx in valgus position
The finding of congenital hallux valgus must raise the possibility of FOP so that management should be early and adequate.