Shyam Roy A Sa, B P Vinod Kumara, Mohammed Sageera, Raffic Ma
a. Department of Orthopaedics, Government Medical College, Thiruvananthapuram

Corresponding Author: Dr. B P Vinod Kumar, Assistant Professor, Department of Orthopaedics, Government Medical College, Thiruvananthapuram. Phone: 9847279516. E-mail: imaksb@yahoo.co.in

ABSTRACT

An eighteen year old male came  to our  out-patient department with contusion right elbow with moderate edema  and tenderness.  X-rays showed  no evidence of fracture. He was treated  with above  elbow  POP slab in 90 degree flexion. He was lost for  follow up and  presented  6 weeks  later  with a swelling in the anterior aspect of arm and inability to flex the elbow to full  range.  He had massage after  removing the plaster. On examination flexion was possible only upto 45 degree  and a bony  hard,  non  tender,  large  non mobile  mass  was  palpated  over  anterior  aspect  of ann. Roentgenographic  examination  showed  an anterior myositis ossificans of  6 x 4 ems in brachialis.  He was treated  conservatively with  indomethacin, isometric muscle  strengthening and  gentle  active assisted  range of muscle  exercises within  the limits of pain. Range  of motion   progressively increased over  a period of 2 months, and he could improve his range  to 110 degree. By another 2 months  he  was able to completely  restore the mobility,  the size of the myositis mass decreased.

Myositis ossificans most commonly occurs following trauma to musculoskeletal system. Patients usually presents with swelling, pain and a decreased range of motion.  But  a myositis mass  of 6 ems is unusual and rare. More than one-half of the patients have a history of injury and with a history of passive movements of involved joints especially elbow  and knee  and   massage. It can  also  occur  without any identifiable fractures.  Von Dusch was first to suggest the  term myositis ossificans in  1868. Myositis ossificans is a  misleading term; lesion is not inflammatory and  an origin  in the muscle  is not a prerequisite for  the diagnosis (Ackennan 1958).1 New bone formed  in myositis lacks periostium and it do not follow anatomical planes. Certain occupations and sports  are reported to have an increased chance of myositis  ossificans in particular areas.  Brachialis in fencers, adductor longus  in horse riders (Prussian disease), deltoid in soldiers, solieus in dancers and quadriceps in foot  ball players  are common due  to repeated  trauma.  In most cases lesion is not attached to the underlying bone, but it can be attached if it lies near the bone and the original injury induced adjacent periosteal reaction. Initially the radiograph shows only faint, irregular, floccular radiodensities  (some times called  dotted-veil pattern; Enzinger et al).3   As the lesion mature, the radiographic appearance changes to that of bone formation, characteristically beginning at the periphery of the lesion. The center of the lesion remains radiolucsent, a characteristic that  can  be demonstrated by CT scan. Serial radiographic studies done over a period of years will show the volume of myositic  mass to decrease gradually. Classically 4 zones  can be demonstrated in mid osseus  phase of the  myositic mass (2-6  wks).1   Inner  most  layer consist  of  highly  active  cells  with  mitotic  figures, adjacent layer  of cellular  osteiod, zone of new bone formation with  trabacular organization and  the peripheral zone of fibrous tissue formation (Ackerman et  al).1  Although the  use  of  aspiration   biopsy  for cytological diagnosis has  been  reported, does  notText Box: • allow to view the cross section of the lesion and there by document the zone phenomenon (Aisner  et al).2 When  a biopsy  of  the  lesion  is warranted, a large sample  of  tissue  that  preserves the  architecture of the mass is essential for the accurate diagnosis (Mina et al).4   Manipulation should be avoided.7  Since the diagnosis could be established with a proper history and imaging studies, an exision is seldom necessary.7 Pharmacological agents used to inhibit heterotopic ossification have disadvantage of causing side effects; both diphosphonates and NSAIDs can interfere with fracture healing, and the former, when  used  for prolonged periods of  as  long   as  six  months as  suggested can  result  in  osteomalacia.8 Radiation therapy  is the only  local measure  available for  the prevention and treatment of myositis.The timing of resection of myositis mass remains controversial because of the risk of recurrent ossification.

Figure-a.-Contusion-Elbow

Figure 1. Contusion® Elbow

Figure-b.-Unusual-large-anterior-myositis-6-weeks.

Figure 2. Unusual large anterior myositis 6 weeks

Figure-c.-Unusual--Large-anterior-myositis-10-weeks

Figure 3 Unusual Large anterior myositis 10 weeks

Failla et al after  a review  of the experience with 20 patients over a 42 year  period,  recommended that operative resection can be delayed for 12 months after the injury but be performed within  3 years.9 Myositis mass i s considered  mature  w h en   serial  radiog raph demonstrate that   the  extent of  the  mass   is  not increasing, that the margin  between  the heterotopic bone and the soft tissue is distinct.

UNUSUALLY LARGE MYOSITIS OSSIFICANS

End Note

Author Information

  1. Dr. Shyam Roy A S, Resident, Department of Orthopaedics, Government Medical College, Thiruvananthapuram
  2. Dr. B P Vinod Kumar, Assistant Professor, Department of Orthopaedics, Government Medical College, Thiruvananthapuram
  3. Dr. Mohammed Sageer, Senior Lecturer, Department of Orthopaedics, Government Medical College, Thiruvananthapuram
  4. Dr. Raffic M, Professor, Department of Orthopaedics, Government Medical College, Thiruvananthapuram

Conflict of Interest: None declared

References

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  2. Aisner SC, Burke KC, Resnik CS. Aspiration cytology of heterotopic ossification. A case report. Acta Cytol. 1992 Apr;36(2):159–62. [Pubmed]
  3. Enzinger F.M. & Weiss .S.W soft tissue tumors; : pp.1.5-7 St. Louis C.V. Mosby  1983
  4. Mirra.J.M; Picci.P & Gold R.H; Bone Tumors; clinical, radiological  and  pathological    correlation. pp: 1550-1575, Philadelphia;  Lea &  Febiger 1989.
  5. Rockwood and Wilkins:.Tames.H.Beaty. M.D & James R Kasser :M.D.  Fractures in children, 5: 724-726,  2001
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  7. Instructional course lectures; The American academy of  orthopaedic surgeons – evaluation diagnosis & classification  of benign soft tissue tumors. Jan 1996, vol 78A. no:1
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