Page 46 - ISAKOS 2020 Newsletter Volume 2

CURRENT CONCEPTS
Difficult Elbow Problems: Heterotopic Ossification and Calcification
Classification
Pathological bone formation around the elbow may assume different forms:
• Calcification: a deposit of calcium inside the capsule or the ligaments, without trabecular structure.
• Ossification: an osseous metaplasia starting from the bone.
• Myositis ossificans: bone formation inside the muscles.
• Myositis proliferans: fibroblast proliferation inside the muscles, without osseous metaplasia.
• Fibrodysplasia ossificans progressiva: a rare congenital condition.
• Tumors.
The most frequently used classification system is the functional classification proposed by Hastings and Graham1 (Table I).
TABLE I. Classification System of Hastings and Graham
Introduction
Etiopathogenesis and Risk Factors
The literature suggests that heterotopic ossification (HO) lesions tend to grow over a period of up to 3 weeks after onset and mature in about 3 to 6 months. These observations may lead one to think that the absence of HO on radiographs 2 weeks after trauma or surgery could be a good prognostic factor. There is disagreement in the literature with regard to the use of pharmacological prophylaxis after an acute event; if used, such treatment seems to be effective immediately after trauma but may not have a role in limiting HO once it has been noticed.
Although the existing literature provides no definitive answer, the etiopathogenesis of HO is likely multifactorial. The neurogenic mechanism seems to be the most promising explanation. The trigger is an external cause that leads to the release of bone morphogenetic protein (BMP), the activation of afferent sensory neurons for pain, and the recruitment of mast cells to peripheral nerves.
Celli Andrea, MD
Hesperia Hospital Modena, ITALY
Matteo Bartoli, MD
Nuovo Ospedale di Sassuolo Modena, ITALY
Gregory I. Bain, MBBS, FRACS, PhD
Flinders University Adelaide, AUSTRALIA
Felix H. Savoie III, MD
Tulane University School of Medicine New Orleans, Louisiana,
UNITED STATES
Luigi A. Pederzini, MD
Nuovo Ospedale di Sassuolo Modena, ITALY Corresponding Author
CLASS I
CLASS II
CLASS III
Radiographic heterotopic ossification without functional limitations
Radiographic heterotopic ossification with subtotal functional limitations
IIA: Limited flexion-extension
IIB: Limited pronation-supination IIC: Limited function in both planes
Radiographic and functional ankylosis IIIA: Ankylosis in flexion-extension IIIB: Ankylosis in pronation-supination IIIC: Ankylosis in both planes
The first ISAKOS webinar on elbow surgery was broadcast worldwide on June 5, 2020. Chairmen Dr. Pederzini and Dr. Bhatia asked opinion leaders in the elbow field to discuss heterotopic ossification and its possible treatments.
44 ISAKOS NEWSLETTER 2020: VOLUME II