Heterotopic Ossification: Difference between revisions

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'''Original Editors '''- Bruce Tan as part of the [[Pathophysiology of Complex Patient Problems|from Bellarmine University's Pathophysiology of Complex Patient Problems project.]]  
'''Original Editors '''- Bruce Tan as part of the [[Pathophysiology of Complex Patient Problems|from Bellarmine University's Pathophysiology of Complex Patient Problems project.]]  
'''Top Contributors''' - {{Special:Contributors/{{FULLPAGENAME}}}}</div>  
'''Top Contributors''' - {{Special:Contributors/{{FULLPAGENAME}}}}</div>  
== Definition/Description  ==


Heterotopic Ossification (HO) refers to the formation of lamellar bone inside soft tissue structures where bone should not exist. The development of HO is extra-articular and occurs outside the joint capsule. The new bone generally does not involve the periosteum. The HO may also attach to the cortex of adjacent bone, with possible cortical disruption.<ref name="p1">Mavrogenis AF, Soucacos PN, Papagelopoulos PJ. Heterotopic Ossification Revisited. Orthopedics. 2011Jan;34(3):177.</ref> This process can occur in structures such as the skin, subcutaneous tissue, skeletal muscle, and fibrous tissue adjacent to bone. In more rare forms, HO has been described in the walls of blood vessels and intra-abdominal sites such as the mesentery.<ref name="p2">McCarthy EF, Sundaram M. Heterotopic ossification: a review. Skeletal Radiol 2005; 34: 609-619.</ref> The primary risk factor for HO is inciting trauma.<ref name="p1" /> Additionally, inflammation has been shown to play a role in the formation of HO due to osteoprogenitor cells being stimulated to proliferate in that environment.<ref name="p3"/> Additional factors are described in further detail in the Etiology section. Although HO can be found at any site, it is most prevalent in the major joints such as the hip, elbow, shoulder and knee.<br>
== Introduction ==
 
Heterotopic ossification is seen often in [[Rehabilitation Contexts|rehabilitation]] population. It refers to the formation of mature, lamellar [[bone]] in extraskeletal soft tissue where bone should not be. Patients at risk of developing heterotopic ossification include patients with [[Burns Overview|burns]], [[Stroke|strokes]], [[Spinal Cord Injury|spinal cord injuries (SCI)]], [[amputations]], joint replacements, and [[Overview of Traumatic Brain Injury|traumatic brain injuries (TBI)]].<ref name=":0">Sun E, Hanyu-Deutmeyer AA. [https://www.ncbi.nlm.nih.gov/books/NBK519029/ Heterotopic Ossification].Available: https://www.ncbi.nlm.nih.gov/books/NBK519029/<nowiki/>(accessed 24.10.2021)</ref>
&nbsp;[[Image:Ho1.jpg|frame|right|Radiograph showing heterotopic ossification of the hip with thanks from LearningRadiology.com]]HO was first described by Patin in 1692 while working with children diagnosed with myositis ossificans progressiva.<ref name="p4">Bossche LV, Vanderstraeten G. Heterotopic ossification: a review. J Rehabil Med 2005; 37: 129-136.5. Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.</ref> In 1918, Dejerine &amp; Ceillier detailed the anatomical, clinical, and histological features of ectopic bone formation in soldiers who sustained spinal injuries during World War I.<ref name="p5">Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.</ref>
 
Following the work of Dejerine &amp; Ceillier, Marshall Urist described the osteoinducive properties of bone morphogenic protein in ectopic areas such as muscle. This was, and still is, considered a "landmark discovery" in orthopedic research.<ref name="p6">Hsu JE, Keenan MA. Current review of heterotopic ossification. UPOJ 2010; 20: 126-130.</ref> Two of the original research articles by Urist can be found below: <br>
 
*[http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=MR&aulast=Urist&atitle=Bone:+formation+by+autoinduction&id=doi:10.1126/science.150.3698.893&title=Science+(New+York,+N.Y.)&volume=150&issue=3698&date=1965&spage=893&issn=0036-8075 Bone: Formation by Autoinduction]
*[http://jdr.sagepub.com/content/50/6/1392.full.pdf Bone Morphogenic Protein]<br>


* Lesions range from small, clinically insignificant foci of ossification to large deposits of bone that cause pain and restriction.
* The most common presentation is with pain around the ossification site<ref>Radiopedia [https://radiopaedia.org/articles/heterotopic-ossification HO] Available: https://radiopaedia.org/articles/heterotopic-ossification<nowiki/>(accessed 24.10.2021)</ref>
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<div class="row">
  <div class="col-md-6">[[Image:HO CT scan.jpg|center|alt=|thumb|'''Figure.1''' CT Scan showing Heterotopic Ossification of Proximal Femur|285x285px]]</div>
  <div class="col-md-6">[[Image:Ho1.jpg|center|alt=|thumb|'''Figure.2''' Radiograph showing Heterotopic Ossification of the Hip|213x213px]]</div>
</div>


== Etiology/Causes <br>  ==
== Etiology ==
The exact mechanism of heterotopic ossification (HO)  in traumatic and neurogenic heterotopic ossification  is unknown, but two common factors precede the formation of heterotopic ossification , the first being trauma or an inciting neurological event.
# Traumatic (fracture, arthroplasty, muscular trauma, joint dislocation, burns). In total joint arthroplasty, heterotopic ossification most commonly occurs for the [[Total Hip Replacement|rep]]<nowiki/>[[Total Hip Replacement|lacement of hips]], [[Total Knee Arthroplasty|knees]], elbow, and [[Total Shoulder Arthroplasty|shoulder]]. Chronic muscular trauma leads to what is traditionally known specifically as traumatic [[Myositis Ossificans|myositis ossificans]]. The most common sites for traumatic [[Myositis Ossificans|myositis ossificans]] are the [[Quadriceps Muscle|quadriceps femoris]] muscle and the [[brachialis]] muscle.
# Neurogenic (Stroke, SCI, TBI, Brain Tumors). The most common sites for neurogenic heterotopic ossification are the hips, elbows (extensor side), shoulders, and knees. Uncommon sites of heterotopic ossification  that may be encountered in a rehabilitation setting are incisions, [[Kidney|kidneys]], uterus, corpora cavernosum, and the gastrointestinal tract. The exact cause and mechanism of neurogenic heterotopic ossification  are unknown.


The exact pathophysiology of HO is unknown. The transformation of primitive mesenchymal cells in connective tissue into osteoblastic tissue and osteoid involve diverse and poorly understood triggers.<ref name="p1" /> These triggers include genetic, post-traumatic, neurogenic, post-surgical, and reactive lesions of hands and feet. [[Image:HO.png|border|right]]  
=== Risk Factors ===
*[[Spasticity]], [[Older People - An Introduction|older age]], [[Pressure Ulcers|pressure ulcer]], the presence of [[Deep Vein Thrombosis|deep vein thrombosis,]] having a tracheostomy, long bone [[Fracture|fractures]], prior injury to the same area, [[Oedema Assessment|edema]], immobility, long-term [[Coma Recovery Scale (Revised)|coma]], and severity of injury (Trauma, TBI, SCI, Stroke).
* High/Moderate risk factors in the THA population include men with bilateral THA, prior history of heterotopic ossification, [[Ankylosing Spondylitis (Axial Spondyloarthritis)|ankylosing spondylitis]], diffuse idiopathic hyperostosis, or [[Paget's Disease]].<ref name=":0" />


Genetic forms include two types: Fibrodysplasia Ossificans Progressiva (FOP) and Progressive Osseous Heteroplasia(POH). These types are described as massive deposits of heterotopic bone around multiple joints in the absence of an inciting event (i.e. trauma). This is the most severe type of HO, progressively forming throughout the life and severely effecting health, life expectancy, and quality of life.<sup><ref name="p2" /></sup>  
== Epidemiology ==
* Heterotopic Ossification is twice as common in males versus females, but it is noted that females older than 65 years old have an increased risk of developing heterotopic ossification.
* The incidence of neurogenic heterotopic ossification is 10% to 20%.<ref name=":0" />
* Following lower extremity amputation: 7%<sup><ref name="p6">Hsu JE, Keenan MA. Current review of heterotopic ossification. UPOJ 2010; 20: 126-130.</ref></sup>
* Following SCI: 20% (ranges reported from 20-40%)<sup><ref name="p6" /></sup>
* Following [[Total Hip Replacement|THA (total hip arthroplasty)]]: 55%<sup><ref name="p1">Mavrogenis AF, Soucacos PN, Papagelopoulos PJ. Heterotopic Ossification Revisited. Orthopedics. 2011Jan;34(3):177.</ref></sup>
* Following Elbow Fracture and/or Dislocation: 90%<ref name="p8">Dalury DF, Jiranek WA. The incidence of heterotopic ossification after total knee arthroplasty. Journal of Arthroplasty 2004; 19: 447-457.</ref><br>


Post-traumatic HO begins with spindle cell proliferation within the first week of the traumatic event. Within 1-2 weeks, primitive osteoid develops. After the second week, primitive cartilage and woven bone can be seen. Trabecular bone forms 2-5 weeks after the trauma. Amorphous calcium phosphate is gradually replaced by hydroxyapatite crystals as the mineralization progresses. After about 6 months, there is an appearance of true bone in the connective tissue between the muscle planes.<sup><ref name="p1" /></sup>  
== Signs and Symptoms ==
[[Image:Heterotopic.jpg|frame|right|'''Figure.3''' Heterotopic Ossification Progression of the Hip]]Clinical signs and symptoms of heterotopic ossification  may appear as soon as 3 weeks or up to 12 weeks after initial musculoskeletal trauma, spinal cord injury, or other precipitating events.<sup><ref name="p9">Shehab D, Elgazzar AH, Collier BD. Heterotopic ossification. Jour of Nuclear Medicine 2002; 43: 346-353.</ref></sup> The first sign of heterotopic ossification is generally loss of joint mobility and subsequently loss of function. Other findings that may suggest the presence of heterotopic ossification include swelling, erythema, heat, pain depending on sensory deficit, hard, palpable mass, pressure area, contracture formation and spasticity and autonomic dysreflexia in individuals with spinal cord injury. In some cases, a fever may be present.<sup><ref name="p1" />&nbsp;</sup>


Neurogenic heterotopic ossification occurs after sickle cell anemia, hemophilia, tetanus, poliomyelitis, multiple sclerosis, and toxic epidermal necrolysis. Neurogenic HO develops only in sites distal to the level of the spinal cord injury. The areas affected by HO are almost always on the affected side of brain injury or stroke.<sup><ref name="p1" /></sup>  
#'''Symptoms:''' Painless Loss of ROM, Interferes with activities of daily living) ADL, [[Complex Regional Pain Syndrome (CRPS)|Complex regional pain syndrome) CRPS]], [[Fever]]
#'''Inspection:''' Warm, Painful, Swollen Joint; may have effusion; Skin Problems (pressure ulcers from contractures around skin, muscles, ligaments, skin maceration and hygiene problems)
#'''Movement:''' Decreased Joint ROM; Joint Ankylosis; with heterotopic ossification after [[Total Knee Arthroplasty|total knee arthroplasty]] (TKA), might develop quadricep muscle snapping or patella instability
#'''Neurovascular:''' Peripheral Neuropathy; heterotopic ossification often impinges on adjacent neurovascular structures<ref name=":1">Orthobullets [https://www.orthobullets.com/pathology/8044/heterotopic-ossification HO] Available: https://www.orthobullets.com/pathology/8044/heterotopic-ossification<nowiki/>(accessed 24.10.2021)</ref>


Post-surgical HO most commonly develops after procedures which require open reduction, internal fixation and joint replacement surgeries, with THA being the most common.<sup><ref name="p2" /></sup>  
=='''Differential Diagnoses'''==
The initial inflammatory phase of heterotopic ossification may mimic other pathologies such as cellulitis, thrombophlebitis, osteomyelitis, or a tumorous process.<sup><ref name="p3">Firoozabadi R, Alton T, Sagi HC. Heterotopic Ossification in Acetabular Fracture Surgery. Journal of the American Academy of Orthopaedic Surgeons. 2017;25(2):117–24.</ref></sup><ref name="p4">Bossche LV, Vanderstraeten G. Heterotopic ossification: a review. J Rehabil Med 2005; 37: 129-136.5. Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.</ref> 


Reactive lesions of the hands and feet are usually associated with the periosteum or periarticular fibrous tissue, which differentiates the category from myositis ossificans. These lesions occur in three clinico-radiologic settings: bizzare parosteal osteochondroma[[Image:HO.jpg|thumb|right]]tous, florid reactive periositis, and subungual exostoses.<sup><ref name="p2" /></sup>
Other differential diagnoses include [[Deep Vein Thrombosis|deep veinous thrombosis (DVT]]), [[Septic (Infectious) Arthritis|Septic Arthritis]], Haematoma, or [[Fracture]]. DVT and heterotopic ossification have been positively associated. This is thought to be due to the mass effect and local inflammation of the HO, encouraging thrombus formation. The thrombus formation is caused by venous compression and phlebitis.<sup><ref name="p1" /></sup>


== Prevalence  ==
== Diagnosis ==
Diagnosis is made when soft tissue ossification with sharp demarcation from surrounding soft tissues is seen on radiograph.<ref name=":1" /> However, plain radiographs may not be able to detect early lesions, so ultrasonography is more commonly used as an early screening modality, despite magnetic resonance imaging remaining the gold standard for imaging of soft tissue masses.<ref name=":2">Devilbiss Z, Hess M, Ho GWK. [https://pubmed.ncbi.nlm.nih.gov/30204632/ Myositis Ossificans in Sport: A Review]. Curr Sports Med Rep. 2018 Sep;17(9):290-295. doi: 10.1249/JSR.0000000000000515. PMID: 30204632. Available:https://pubmed.ncbi.nlm.nih.gov/30204632/ (accessed 25.10.2021)</ref><div class="row">
 
<div class="col-md-6">[[Image:Shoulder HO CT 2.JPG|center|'''Figure.4''' CT Scan showing Heterotopic Ossification of the Shoulder|alt=|thumb|300x300px]]</div>
  <div class="col-md-6">[[Image:Shoulder HO Xray 2.JPG|center|'''Figure.5''' AP X-ray Showing Heterotopic Ossification of Shoulder|alt=|thumb|300x300px]]</div>
</div>


• Following lower extremity amputation: 7%<sup><ref name="p6" /></sup><br>• Following TBI: 11% (ranges reported from 10-20%)<sup><ref name="p6" /></sup><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Hip most common, followed by elbow<sup><ref name="p1" /><ref name="p7">Foruria AM, Augustin S, Morrey BF, Sanchez-Sotelo Joaquin. Heterotopic Ossification After Surgery for Fractures and Fractures-Dislocations Involving the Proximal Aspect of the Radius or Ulna. The Journal of Bone and Joint Surgery, Incorporated. 2015May15;95-A(10):e66(1)-e66(7).</ref></sup><br>• Following SCI: 20% (ranges reported from 20-40%)<sup><ref name="p6" /></sup><br>• Following THA: 55%<sup><ref name="p1" /></sup><br>• Following elbow fracture and/or dislocation: 90%<ref name="p8">Dalury DF, Jiranek WA. The incidence of heterotopic ossification after total knee arthroplasty. Journal of Arthroplasty 2004; 19: 447-457.</ref><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Following forearm fracture: 20% <br>  
== Associated Co-Morbidities ==
The most common conditions found in conjunction with heterotopic ossification:<sup><ref name="p4" /> <ref name="p2">McCarthy EF, Sundaram M. Heterotopic ossification: a review. Skeletal Radiol 2005; 34: 609-619.</ref></sup>  


In a recent study, Foruria et al. looked at the prevalence of heterotopic ossification in all elbow pathologies entering an emergency room over a 5 year period. They found the highest prevalence of HO occurred in terrible triad injuries, transolecranon fracture-dislocations, and an associated distal humeral fracture. The location of the ossification was most commonly found on the posterior aspect of the ulna. Risk factors for HO include dislocation or subluxation at the time of injury, open injury, and severe chest injury. When a pathology was treated surgically, 37% of participants developed an ossification.<sup><ref name="p7" /></sup><br>
*[[Ankylosing Spondylitis]]
*[[Rheumatoid Arthritis|Rhuematoid Arthritis]]<sup><ref name="p7">Foruria AM, Augustin S, Morrey BF, Sanchez-Sotelo Joaquin. Heterotopic Ossification After Surgery for Fractures and Fractures-Dislocations Involving the Proximal Aspect of the Radius or Ulna. The Journal of Bone and Joint Surgery, Incorporated. 2015May15;95-A(10):e66(1)-e66(7).</ref></sup>
*Hypertrophic Osteoarthritis
*[[Diffuse Idiopathic Skeletal Hyperostosis]]
*[[Paget's Disease]]
*[[Spinal Cord Injury]] <br>


== Clinical Diagnosis<br> ==
== Treatment ==
Heterotopic Ossification is best managed by an interprofessional team. The condition is not only difficult to diagnose because of lack of specific markers but its treatment is not satisfactory. Current treatment recommendations consist of mobilisations with gentle ROM exercises, indomethacin, etidronate, and surgical resection.
* Early treatment with a passive range of motion exercises should be implemented once the presence of HO is confirmed to prevent ankylosing of joints.
* Absolute treatment consists of surgical resection of mature bone once the HO has fully matured. This can be 12 to 18 months after the initial presentation.
* Surgical consultation with an orthopaedic surgeon is warranted only if there will be an improvement in function as demonstrated by mobility, transfers, hygiene, and ADLs.
* Indomethacin and etidronate are also used to help arrest bone formation in HO, but efficacy in the traumatic brain injury population has not been clearly proven (see below).
* The most effective treatment option in the TBI population is surgical resection. In the SCI population, the most effective [[NSAIDs|Non-Steroidal Anti-Inflammatory Drugs (NSAID)]] treatment regiments are either Rofecoxib 25 mg per day for 4 weeks or indomethacin 75 mg daily for 3 weeks.<ref name=":0" />


Clinical signs and symptoms of HO may appear as soon as 3 weeks or up to 12 weeks after initial musculoskeletal trauma, spinal cord injury, or other precipitating events.<sup><ref name="p9">Shehab D, Elgazzar AH, Collier BD. Heterotopic ossification. Jour of Nuclear Medicine 2002; 43: 346-353.</ref></sup> The first sign of HO is generally loss of joint mobility and subsequently loss of function. Other findings that may suggest the presence of HO include swelling, erythema, heat, local pain, palpable mass, and contracture formation. In some cases, a fever may be present.<sup><ref name="p1" />&nbsp;</sup>[[Image:Heterotopic.jpg|frame|right|Heterotopic ossification progression of the hip]]
== Medications ==
The two types of medications shown to have both prophylactic and treatment benefits are as follows:  
# Non-Steroidal Anti-Inflammatory Drugs (NSAIDS)<br>Indomethacin (two-fold action)
#* Inhibition of the differentiation of mesenchymal cells into osteogenic cells (direct)
#* Inhibition of post-traumatic bone remodelling by suppression of prostaglandin-mediated response (indirect) and anti-inflammatory properties
# Biphosphonates: Three-fold action
#* Inhibition of calcium phosphate precipitation
#* Slowing of hydroxyapatite crystal aggregation
#* Inhibition of the transformation of calcium phosphate to hydroxyapatite.


'''Differential Diagnoses:''' The initial inflammatory phase of HO may mimic other pathologies such as cellulitis, thrombophlebitis, osteomyelitis, or a tumorous process.<sup><ref name="p3" /></sup><ref name="p4" /> Other differential diagnoses include DVT, septic arthritis, hematoma, or fracture. DVT and HO have been positively associated. This is thought to be due to the mass effect and local inflammation of the HO, encouraging thrombus formation. The thrombus formation is caused by venous compression and phlebitis.<sup><ref name="p1" /></sup>
== '''Surgical Interventions''' ==
 
The two main goals of surgical intervention are to
<sup></sup><br>
# Alter the position of the affected joint  
 
# Improve its range of motion (ROM).<ref name="p5">Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.</ref>  
== Classification Systems <sup></sup><br> ==
<br>
 
Rehabilitation Post-Operatively: It is recommended that a rehabilitation program should start within the first 24 hours after surgery. The program should last for 3 weeks to prevent adhesion.<sup><ref name="p7" /></sup>  
'''Brooker Classification of Heterotopic Ossification (Following THA)'''<sup><ref name="p0">Hug KT, Alton TB, Gee AO. In Brief: Classifications in Brief: Brooker Classification of Heterotopic Ossification After Total Hip Arthroplasty. Clinical Orthopaedics and Related Research®. 2014;473(6):2154–7.</ref></sup>
 
Class 1: Island of bone within a soft tissue about the hip <br>Class 2: Bone spurs originating from the pelvis of proximal end of femur leaving at least 1 cm between opposing bone surfaces <br>Class 3: Bone spurs originating from pelvis or proximal femur leaving &lt;1 cm between opposing bone surfaces <br>Class 4: Ankyloses of the hip
 
Brooker did not describe a class 0 but subsequent studies using the Brooker classification have defined Class 0 as the absence of radiographic HO.  
 
'''Schmidt and Hackenbrock Classification of Heterotopic Ossification (Following THA)'''<sup><ref name="p1" /></sup>
 
Region 1: Heterotopic ossification strictly below the tip of the greater trochanter <br>Region 2: Heterotopic ossification below and above the tip of the greater trochanter <br>Region 3: Heterotopic ossification strictly above the tip of the greater trochanter
 
Grade A: Single or multiple heterotopic ossification &lt;10 mm in maximal extent without contact with pelvis or femur <br>Grade B: Heterotopic ossification &gt;10 mm without contact with the pelvis but with possible contact with the femur; no bridging from the femur to&nbsp; the proximal part of the greater trochanter; no evidence of ankyloses <br>Grade C: Ankylosis by means of firm bridging from femur to pelvis
 
'''McAfee’s Classification of Heterotopic Ossification (Following Total Disc Arthroplasty)'''<sup><ref name="p1"/></sup>  
 
0: No HO <br>1: Islands of bone not within the margins of the disc and not interfering with motion <br>2: Bone within the margins of the disc but not blocking motion <br>3: Bone within the margins of the disc and interfering with motion of the prosthesis <br>4: Bone ankylosis
 
== Stages of Development <br>  ==
 
'''Chronology of Development of Heterotopic Ossification'''<sup><ref name="p2"/></sup>
 
*0 days: +/- erythema, swelling, tenderness
*7 days: clinically palpable mass
*7-14 days: poorly defined shadow on radiograph
*14-21 days: osteoid deposition, radiographic shadows
*21-35 days: fluffy radiodensities; the “dotted veil” effect
*24 days: definite radiographic evidence
*30 days: mineralization shows a zonal pattern (best seen on CT scan)
*45 days: histologic “zonal” pattern evident, reflecting well-formed mineralization at the periphery
*180-365 days: development of mature bone


== Prognosis ==
Complications of  heterotopic ossification present itself through decreased function and mobility, peripheral nerve entrapment, and pressure ulcers.
# Up to 70% of cases involving HA are asymptomatic.
# Ankylosis, vascular compression, and lymphedema can also be complications manifested in HO.
# Prognosis is generally good after surgery. Mean time from injury to surgery is 3.6 years. Once the surgery is performed, studies have shown that average ROM in the hip can improve from 24.3 to. After surgery, improvement was maintained in follow up 6 months after surgery. Complications from surgical resection of HO, such as infection, severe hematoma, and DVT<ref name=":0" />
<br>
<br>
In the case of sporting myositis ossificans, usually athletes are able to progress to light activity at 2 to 3 months, full activity by 6 months, and back to their pre-injury level by 1 year.<ref name=":2" />


== Diagnostic Tests and Lab Tests ==
== Physical Therapy Management ==
 
Physical therapy has been shown to benefit patients suffering from heterotopic ossification. Pre-operative PT can be used to help preserve the structures around the lesion. ROM exercises (PROM, AAROM, AROM) and strengthening will help prevent muscle atrophy and preserve joint motion. <blockquote>'''''Clinical Note''''': Caution must be taken when working with patients with known heterotopic lesions. Therapy which is too aggressive can aggravate the condition and lead to inflammation, erythema, haemorrhage, and increased pain. </blockquote>Post-operative rehabilitation has also shown to benefit patients with recent surgical resection of heterotopic&nbsp;ossification. The post-op management of HO is similar to pre-op treatment but much more&nbsp;emphasis is placed on [[Edema Assessment|edema]] control, [[Scar Management|scar management]], and [[Infection Prevention and Control|infection prevention]].&nbsp;Calandruccio et al. outlined a rehabilitation protocol for patients who underwent surgical excision of heterotopic ossification of the elbow. The phases of rehab and goals for each phase are as follows:<sup><ref name="p6"/></sup>
'''Ultrasonography'''<sup><ref name="p3">Firoozabadi R, Alton T, Sagi HC. Heterotopic Ossification in Acetabular Fracture Surgery. Journal of the American Academy of Orthopaedic Surgeons. 2017;25(2):117–24.</ref></sup>[[Image:HO bone scan.jpg|frame|right|Bone Scan showing HO of Hip]]<br>• Detection of HO 2 weeks earlier than by x-ray <br>• More accurate than any laboratory tests<br>• Help clinicians advocate for prompt/aggressive physical therapy <br>• Eliminates high false-positive rate of physical exam alone <br> <br> '''Three-phase bone scintigraphy'''<sup><ref name="p4" /></sup><br> • Diagnostic and therapeutic follow-up purposes<br>• Phases 1 and 2 are indicative of hyperemia and blood pooling (precursors to process of HO)<br>• Usually positive after 2-4 weeks<br>• Serial bone scans used to monitor metabolic activity of HO to determine optimal timing for surgical resection and to predict postoperative occurrence <br><br> '''Radiography'''<sup><ref name="p1" /></sup><br>• Soft tissue mass is the earliest radiographic finding<br>• HO seen on radiographs 4-6 weeks post-injury has a typical appearance of circumferential ossification with a lucent center<br>• Cannot detect the mineralization of HO during first weeks after trauma/onset<br>• Frequently used to classify HO following THA <br>• Differential diagnosis: avulsion fracture fragments, osteochondral bodies, nonosseous soft tissue calcification and osteosarcoma<br> <br> '''MRI and CT Scan'''<sup><ref name="p1" /></sup><br> [[Image:HO CT scan.jpg|frame|right|CT scan showing heterotopic ossification of proximal femur]] • MRI not routinely used for evaluation of HO<br> • CT may detect soft tissue ossification at earlier stages than standard radiograph<br> <br> '''Three-phase technetium-99m (99mTc) methylene diphosphonate bone scan'''<sup><ref name="p1" /></sup>
 
• Most sensitive imaging modality for early detection and assessing the maturity of HO<br>• Can use to monitor the metabolic activity of HO and determine appropriate time for surgery and predict postoperative recurrence<br>• Usually positive &gt;2 weeks before radiographic evidence of HO<br>
 
<br>
 
'''Prostaglandin E2: (PGE2)'''<ref name="p4"/><br>• Monitior PGE2 excretion in 24-hour urinalysis<br>• PGE2 felt to be reliable bone marker for early detection and determining treatment efficacy <br>• A sudden increase is an indication for bone scintigraphy<br><br>
 
'''Alkaline Phosphatase: (ALP)'''<ref name="p5"/><br>• Frequently used in early detection of HO<br>&nbsp; &nbsp; &nbsp;&nbsp; ALP values are increased in early HO and plateau at ~4 weeks<sup><ref name="p3" /></sup><br>• Cannot be used to draw clinical conclusions about maturity or recurrence of HO<br>• Acute fractures often have similar ALP values, limiting the usefulness of ALP values in diagnosis of HO<sup><ref name="p3" /></sup><br> <br>
 
'''Elevated Creatine Kinase Levels'''<sup><ref name="p1" /></sup><br>• Correlate with histologic involvement of muscle and severity of disease<br>• Not specific to HO<br>• May predict a higher risk for HO development and severity <br>• May be helpful in planning and evaluation of response to treatment <br><br>
 
'''Matrix Metalloproteinase-9'''<sup><ref name="p3" /></sup><br>• Marine animal models suggest this could be an early biomarker for HO formation


<br> ''Clinical Note'': the lack of simple objective measures in detecting heterotopic bone formation causes HO to be misdiagnosed in the early stages, leading to delayed treatment.<sup><ref name="p6" /></sup><br><br>
=== Phase I'''&nbsp;'''(Week 1) ===
[[Image:Elbow HO.png|frame|right|Elbow Heterotopic Ossification]]


== Systemic Involvement  ==
'''Goals:'''
 
Evidence shows that there are no systemic effects secondary to the formation of heterotopic ossification. The most common sites where this condition presents are&nbsp;the hips, knees, spine, elbow, wrists, hands, and any site&nbsp;which is involved in a traumatic event. &nbsp;
 
== Associated Co-Morbidities <br>  ==
 
The most common conditions found in conjunction with heterotopic ossification:<sup><ref name="p4" /> <ref name="p2" /></sup>
 
*Ankylosing spondylitis
*Rhuematoid arthritis<sup><ref name="p7" /></sup>
*Hypertrophic osteoarthritis
*Diffuse idiopathic skeletal hyperostosis
*Paget's disease
*Quadriplegia and paraplegia <br>
 
== Medical Management (Current Best Evidence)  ==
 
[[Image:Shoulder HO CT 2.JPG|frame|right|CT Scan showing heterotopic ossification of the shoulder (Chao et al.)]]
 
The treatment of heterotopic ossification is largely dependent on the amount of ectopic bone formation, the location and the associated functional limitations of the patient.
 
The first goal of medical management is to identify those patients at risk for developing HO and treating them prophylactically. Research supports two other approaches for the medical management of HO: 1)surgical excision and 2) radiation therapy.<br>
 
<u>'''Prophylactic Treatment:'''</u>
 
Further research needs to be done in this area, however there are currently experimental options. These include:
 
'''Local radiation therapy'''
 
*Decreased incidence of all Brooker classes of HO following THA, but has greater effect on preventing Brooker classification 3 and 4 compared to NSAIDS
*Post-operative better than pre-operative<sup><ref name="p3" /></sup><br>
*The use of radiotherapy as a prophylactic treatment comes mainly from the literature concerning total hip arthroplasty.<sup><ref name="p6" /></sup>
*Radiating pluripotential mesenchymal cells may effectively prevent the development of HO.<sup> <ref name="p5" /></sup>
*A dose of 700-800 cGy of local radiation in the first four post-operative days has shown to prevent HO formation in patients who are at high risk.<sup><ref name="p6" /> </sup><br>
 
'''Oral indomenthacin '''<br>
 
<br>
 
<u>'''Medications:'''</u>
 
Medications are prescribed to patients who are at risk for developing heterotopic ossification for preventative measures and to aid in the treatment after formation of heterotopic lesions. The two types of medications shown to have both prophylactic and treatment benefits are as follows:
 
'''Non-steroidal anti-inflammatory drugs: NSAIDS'''<br>Indomethacin (two-fold action)<br>1. Inhibition of the differentiation of mesenchymal cells into osteogenic cells (direct)<br>2. Inhibition of post-traumatic bone remodeling by suppression of prostaglandin-mediated response (indirect) and anti-inflammatory properties[[Image:Shoulder HO Xray 2.JPG|frame|right|AP x-ray of same shoulder as above (Chao et al.)]]
 
'''Biphosphonates''':<br>Three-fold action<br>1. Inhibition of calcium phosphate precipitation<br>2. Slowing of hydroxyapatite crystal aggregation<br>3. Inhibition of the transformation of calcium phosphate to hydroxyapatite<br>&nbsp;<br>
 
'''''Clinical Note'''''<b>: </b>Clinicians must be aware of potential complications (mainly GI related) with patients taking NSAIDS on a routine basis.<br>
 
<br>
 
<u>'''Sugical intervention:'''</u><br>
 
The two main goals of surgical intervention are to alter the position of the affected joint or improve its range of motion (ROM).<ref name="p5" /> Through his work, Garland has created a recommended timetable for surgical intervention:<sup><ref name="p4" /></sup>
 
*6 months following traumatic development of HO
*1-year following development of HO secondary to a spinal cord injury<br>
*18 months following development of HO secondary to head injury<br>
 
The above timetables were established to determine the most optimal timing of surgical intervention. Clinicians must determine if the lesion has reached maturation before surgical excision to decrease the risk of intraoperative complications such as hemorrhage, and the reoccurrence of the ectopic lesion.<sup><ref name="p9" /></sup> The use of bone scans to determine metabolic activity of the lesion and serum ALP levels are common aids in this decision making process. [[Image:Shoulder HO CT3D 2.JPG|frame|right|3D CT reconstruction of same shoulder (Chao et al.)]]
 
Shehab et al. describes criteria for recommending surgical removal of heterotopic ossification. The criteria are as follows:<sup><ref name="p9" /></sup>
 
#Significantly limited ROM of involved joint (e.g., hip should have &lt; 50 deg ROM) for most patients, progression to joint ankylosis is the most serious complication of heterotopic ossification.
#Absence of local fever, swelling, erythema, or other clinical findings of acute heterotopic ossification.
#Normal serum alkaline phosphate levels.
#Return of bone scan findings to normal or near normal; if serial quantitative bone scans are obtained, there should be a sharply decreasing trend followed by a steady state for 2-3 months.<br>
 
{{#ev:youtube|AGewib-kl1A}}
 
'''Rehabilitation Post-Operatively'''
 
It is recommended that a rehabilitation program should start within the first 24 hours after surgery. The program should last for 3 weeks to prevent adhesion.<sup><ref name="p7" /></sup>
 
== Physical Therapy Management <br>  ==
 
Physical therapy has been shown to benefit patients suffering from heterotopic ossification. Pre-operative PT can be used to help preseve the structures around the lesion. ROM exercises (PROM, AAROM, AROM) and strengthening will help prevent muscle atrophy and preserve joint motion.
 
'''<u>''Clinical note''</u>''': caution must be taken when working with patients with known heterotopic lesions. Therapy which is too aggressive can aggravate the condition and lead to inflammation, erythema, hemorrhage, and increased pain.
 
Post-operative rehabilitation has also shown to benefit patients with recent surgical resection of heterotopic&nbsp;ossification. The post-op management of HO is similar to pre-op treatment but much more&nbsp;emphasis is placed on edema control, scar management, and infection prevention.&nbsp;Calandruccio et al. outlined a rehabilitation protocol for patients who underwent surgical excision of heterotopic ossification of the elbow. The phases of rehab and goals for each phase are as follows:<sup><ref name="p6"/></sup>
 
<u>'''Phase I'''</u>'''&nbsp;'''(Week 1) [[Image:Elbow HO.png|frame|right|Heterotopic ossification of the elbow]]
 
<u></u>Goals:


#Prevent infection  
#Prevent infection  
Line 188: Line 109:
#Maintain ROM of joint proximal and distal to surgical site
#Maintain ROM of joint proximal and distal to surgical site


<u>'''Phase II'''</u>'''&nbsp;'''(2-8 weeks)  
=== Phase II&nbsp;(2-8 Weeks) ===
'''Goals:'''


<u></u>Goals:<u></u>
#Reduce ain
 
#Manage [[Oedema Assessment|Edema]]
#Reduce pain
#Encourage limited ADL performances
#Manage edema
#Promote Scar Mobility and proper remodeling
#Encourage limited ADL performances  
#Promote full ROM of affected joint
#Promote scar mobility and proper remodeling  
#Promote full ROM of affected joint  
#Encourage quality muscle contractions [[Image:Hand-elbow-horiz01.jpg|frame|right|Photo courtesy of prosportscare.com]]
#Encourage quality muscle contractions [[Image:Hand-elbow-horiz01.jpg|frame|right|Photo courtesy of prosportscare.com]]


<u>'''Phase III''' </u>(9-24 weeks)  
=== Phase III (9-24 Weeks) ===
'''Goals:'''


Goals:
#Self-manage Pain
 
#Prevent flare-up with functional activities
#Self-manage pain
#Improve Strength
#Prevent flare-up with functional activities  
#Improve ROM (if still limited)
#Improve strength
#Improve ROM (if still limited)  
#Return to previous levels of&nbsp;activity&nbsp;
#Return to previous levels of&nbsp;activity&nbsp;
Casavant and Hastings also provide great insight into the evaluation and management of heterotopic ossification in their article titled&nbsp;[http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=AM&aulast=Casavant&atitle=Heterotopic+ossification+about+the+elbow:+a+therapist%27s+guide+to+evaluation+and+management&title=Journal+of+hand+therapy&volume=19&issue=2&date=2006&spage=255&issn=0894-1130 Heterotopic Ossification about the Elbow: A Therapist’s Guide to Evaluation and Management].<sup><ref name="p7"/></sup>
'''''<u>Clinical Note</u>'': '''The two studies used above were primarily focused on rehabiliatation of the elbow secondary to heterotopic ossification. However, the goals and stages of the rehabilitation process can be used as a guide when treating at other sites.
<br>
== Case Report<br>  ==
'''Title:''' Heterotopic Ossification Causing Radiculopathy after Lumbar Total Disc Arthroplasty
'''Key Words:''' Heterotopic Ossification, physical therapy, total disc arthroplasty, radiculopathy
'''Word Count:''' 520
'''Authors: '''Keith L. Jackson, Justin M. Hire, Jeremy M. Jacobs, Charles C. Key and John G. DeVine (modified by Morgan Blake and Hannah McCabe) 
'''Abstract: '''
This case details the complications one man experienced due to the development of post-operative Heterotopic Ossification in his lumbar spine.   
'''Introduction: '''
A total disc arthroplasty is a relatively new treatment strategy for lumbar discogenic back pain that has shown promising short- and intermediate-term results. Specific complications that can accompany total disc arthroplasty include vertebral body fracture, heterotopic ossification (HO), implant malposition, and early or late component extrusion. This case details a posterior component placement contributed to heterotopic bone growth within the spinal canal, causing neural impingement and radiculopathy and ultimately requiring component extraction, decompression, and lumbar arthrodesis.
'''Case Presentation:''' 
*<u>Subjective:</u> 45 y/o male presents to the clinic with new onset R leg pain. He denies paresthesias or the loss of motor function, and he also denied a prior history of HO formation, trauma, or inflammatory arthritis. His PMH includes L5/S1 lumbar total disc arthroplasty 2 years ago for discogenic back pain. He reports that following surgery he had a significant reduction in his symptoms but developed this new pain about 6 months ago. 
*<u>Demographic Information:</u> 45 years old, Male, works for UPS as a mail carrier
*<u>Medical diagnosis:</u> suspicion of HO
*<u>Co-morbidities:</u> HTN, DM
*<u>Previous care/treatment:</u> physical therapy (minimal improvements were noted)
*<u>Self-report outcomes:</u> Oswestry: 46% (Severe Disability) 
*<u>Objective:</u> Physical examination revealed limited lumbar ROM in forward flexion due to R leg pain, positive single leg raise test, strength was 5/5 for all major muscle groups, intact sensation, and normal (2+) reflexes.
Patient was referred to his primary care provider who performed additional testing. Results of additional testing were:
*Radiographs demonstrated implant encroachment into the spinal canal with heterotopic bone formation outside the margins of the disc.
*Computed Tomography Myelogram revealed compression of the traversing nerve root secondary to the inferior endplate of the implant that resided posterior to the margin of the vertebral endplate as well as an associated posterior bone growth further into the canal.
'''Clinical Impression:'''
Patient demonstrates decreased lumbar ROM, with a history of trauma to the lumbar spine due to the lumbar disc arthroplasty. These factors and the positive imaging resulted in the patient being diagnosed with HO. 
'''Intervention:'''
Patient elected to undergo surgical removal of his lumbar arthroplasty with fusion of L5/S1 and HO decompression. Patient returned to physical therapy post operatively for recovery.
'''Outcomes:'''<br>
6 weeks post operatively patient reports complete relief of his radicular leg pain. Radiographs demonstrate a solid fusion without recurrence of HO formation.
'''Discussion:'''
As a physical therapist it is important to consider HO in your differential diagnosis when treating patients with a history of trauma or surgery. It is especially important to remember the signs and symptoms of HO when treating patients with limited ROM. We may be the first health professional to recognize the development of HO.
'''Acknowledgements:'''
Case adapted from “Heterotopic Ossification Causing Radiculopathy after Lumbar Total Disc Arthroplasty”<sup><ref name="p8"/></sup><br><br>
== Case Studies  ==
Tibiofibular Syndesmosis and Ossification. Case Report: Sequelae of Ankle Sprains in an Adolescent Football Player.
*[http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=MA&aulast=Kennedy&atitle=Tibiofibular+syndesmosis+and+ossification.+Case+report:+Sequelae+of+ankle+sprain+in+an+adolescent+football+player1&title=Journal+of+emergency+medicine&volume=18&issue=2&date=2000&spage=233&issn=0736-4679 Kennedy MA, Sama AE, Sigman M.&nbsp;Tibiofibular syndesmosis and ossification. case report: sequelae of ankle sprain in an adolescent football player. Journ of Emer Med 2000; 18: 233-240.]
Heterotopic Mesenteric Ossification ("intraabdominal myositis ossificans): A Case Report.
*[http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=G&aulast=Bovo&atitle=Heterotopic+mesenteric+ossification+(%E2%80%9Cintraabdominal+myositis+ossificans%E2%80%9D):+a+case+report&id=doi:10.1177/106689690401200416&title=International+journal+of+surgical+pathology&volume=12&issue=4&date=2004&spage=407&issn=1066-8969 Bovo G, Romano F, Perego E, Franciosi C et al.&nbsp;Heterotopic mesenteric ossification ("intraabdominal myositis ossificans"): a case report. International Journal of&nbsp;Surgical Pathology 2004; 12: 407-409.]
A Case of Psoas Ossification from the use of BMP-2 for Posterolateral Fusion at L4-L5.
*[http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=RS&aulast=Brower&atitle=A+case+of+psoas+ossification+from+the+use+of+BMP-2+for+posterolateral+fusion+at+L4-L5&id=doi:10.1097/BRS.0b013e31817c4f1c&title=Spine+(Philadelphia,+Pa.+1976)&volume=33&issue=18&date=2008&spage=E653 Brower RS, Vickroy NM.&nbsp;A case of psoas ossification from the use of BMP-2][http://ck8zf4yc8t.scholar.serialssolutions.com/?sid=google&auinit=RS&aulast=Brower&atitle=A+case+of+psoas+ossification+from+the+use+of+BMP-2+for+posterolateral+fusion+at+L4-L5&id=doi:10.1097/BRS.0b013e31817c4f1c&title=Spine+(Philadelphia,+Pa.+1976)&volume=33&issue=18&date=2008&spage=E653 <br>for posterolateral fusion at L4–L5.Spine 2008; 18: 653-655.]&lt;span id="fck_dom_range_temp_1299789628126_629" /&gt;
Infrapatellar Heterotopic Ossification after Anterior Cruciate Ligament Reconstruction.
*[http://web.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=871dbea2-5362-4d15-b847-4613cbaa959f%40sessionmgr114&vid=5&hid=127 Valencia H, Gavín C. Infrapatellar heterotopic ossification after anterior cruciate ligament reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal Of The ESSKA [serial on the Internet]. (2007, Jan), [cited March 31, 2011]; 15(1): 39-42. Available from: MEDLINE.]
Heterotopic Ossification of the Ulnar Collateral Ligament: A Description of a Case in a Top Level Weightlifting Athlete.
*[http://proquest.umi.com/pqdweb?index=65&did=942792311&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1301603092&clientId=1870 A Giombini, L Innocenzi, G Massazza, F Fagnani, et al. Heterotopic ossification of the ulnar collateral ligament: a description of a case in a top level weightlifting athlete. Journal of Sports Medicine and Physical Fitness. 2005 Sep 1;45(3): 370-80. In: ProQuest Medical Library [database on the Internet] [cited 2011 Mar 31]. Available from: ProQuest; Document ID: 942792311]
== Resources <br>  ==
[http://www.unitedspinal.org/publications/action/2007/09/05/the-mystery-of-heterotopic-ossification-and-how-it-affected-my-life/ The Mystery of Heterotopic Ossification and How it Affected My Life]
== References  ==
== References  ==


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[[Category:Bellarmine_Student_Project]]
[[Category:Bellarmine_Student_Project]]
[[Category:Bone - Conditions]]
[[Category:Neurological - Conditions]]

Latest revision as of 02:02, 9 March 2023

Original Editors - Bruce Tan as part of the from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Bruce Tan, Morgan Yoder, Hannah McCabe, Naomi O'Reilly, Lucinda hampton, Admin, Elaine Lonnemann, 127.0.0.1, Wendy Walker, WikiSysop and Kim Jackson

Introduction[edit | edit source]

Heterotopic ossification is seen often in rehabilitation population. It refers to the formation of mature, lamellar bone in extraskeletal soft tissue where bone should not be. Patients at risk of developing heterotopic ossification include patients with burns, strokes, spinal cord injuries (SCI), amputations, joint replacements, and traumatic brain injuries (TBI).[1]

  • Lesions range from small, clinically insignificant foci of ossification to large deposits of bone that cause pain and restriction.
  • The most common presentation is with pain around the ossification site[2]


Figure.1 CT Scan showing Heterotopic Ossification of Proximal Femur
Figure.2 Radiograph showing Heterotopic Ossification of the Hip

Etiology[edit | edit source]

The exact mechanism of heterotopic ossification (HO) in traumatic and neurogenic heterotopic ossification is unknown, but two common factors precede the formation of heterotopic ossification , the first being trauma or an inciting neurological event.

  1. Traumatic (fracture, arthroplasty, muscular trauma, joint dislocation, burns). In total joint arthroplasty, heterotopic ossification most commonly occurs for the replacement of hips, knees, elbow, and shoulder. Chronic muscular trauma leads to what is traditionally known specifically as traumatic myositis ossificans. The most common sites for traumatic myositis ossificans are the quadriceps femoris muscle and the brachialis muscle.
  2. Neurogenic (Stroke, SCI, TBI, Brain Tumors). The most common sites for neurogenic heterotopic ossification are the hips, elbows (extensor side), shoulders, and knees. Uncommon sites of heterotopic ossification that may be encountered in a rehabilitation setting are incisions, kidneys, uterus, corpora cavernosum, and the gastrointestinal tract. The exact cause and mechanism of neurogenic heterotopic ossification are unknown.

Risk Factors[edit | edit source]

Epidemiology[edit | edit source]

  • Heterotopic Ossification is twice as common in males versus females, but it is noted that females older than 65 years old have an increased risk of developing heterotopic ossification.
  • The incidence of neurogenic heterotopic ossification is 10% to 20%.[1]
  • Following lower extremity amputation: 7%[3]
  • Following SCI: 20% (ranges reported from 20-40%)[3]
  • Following THA (total hip arthroplasty): 55%[4]
  • Following Elbow Fracture and/or Dislocation: 90%[5]

Signs and Symptoms[edit | edit source]

Figure.3 Heterotopic Ossification Progression of the Hip

Clinical signs and symptoms of heterotopic ossification may appear as soon as 3 weeks or up to 12 weeks after initial musculoskeletal trauma, spinal cord injury, or other precipitating events.[6] The first sign of heterotopic ossification is generally loss of joint mobility and subsequently loss of function. Other findings that may suggest the presence of heterotopic ossification include swelling, erythema, heat, pain depending on sensory deficit, hard, palpable mass, pressure area, contracture formation and spasticity and autonomic dysreflexia in individuals with spinal cord injury. In some cases, a fever may be present.[4] 

  1. Symptoms: Painless Loss of ROM, Interferes with activities of daily living) ADL, Complex regional pain syndrome) CRPS, Fever
  2. Inspection: Warm, Painful, Swollen Joint; may have effusion; Skin Problems (pressure ulcers from contractures around skin, muscles, ligaments, skin maceration and hygiene problems)
  3. Movement: Decreased Joint ROM; Joint Ankylosis; with heterotopic ossification after total knee arthroplasty (TKA), might develop quadricep muscle snapping or patella instability
  4. Neurovascular: Peripheral Neuropathy; heterotopic ossification often impinges on adjacent neurovascular structures[7]

Differential Diagnoses[edit | edit source]

The initial inflammatory phase of heterotopic ossification may mimic other pathologies such as cellulitis, thrombophlebitis, osteomyelitis, or a tumorous process.[8][9]

Other differential diagnoses include deep veinous thrombosis (DVT), Septic Arthritis, Haematoma, or Fracture. DVT and heterotopic ossification have been positively associated. This is thought to be due to the mass effect and local inflammation of the HO, encouraging thrombus formation. The thrombus formation is caused by venous compression and phlebitis.[4]

Diagnosis[edit | edit source]

Diagnosis is made when soft tissue ossification with sharp demarcation from surrounding soft tissues is seen on radiograph.[7] However, plain radiographs may not be able to detect early lesions, so ultrasonography is more commonly used as an early screening modality, despite magnetic resonance imaging remaining the gold standard for imaging of soft tissue masses.[10]

Figure.4 CT Scan showing Heterotopic Ossification of the Shoulder
Figure.5 AP X-ray Showing Heterotopic Ossification of Shoulder

Associated Co-Morbidities[edit | edit source]

The most common conditions found in conjunction with heterotopic ossification:[9] [11]

Treatment[edit | edit source]

Heterotopic Ossification is best managed by an interprofessional team. The condition is not only difficult to diagnose because of lack of specific markers but its treatment is not satisfactory. Current treatment recommendations consist of mobilisations with gentle ROM exercises, indomethacin, etidronate, and surgical resection.

  • Early treatment with a passive range of motion exercises should be implemented once the presence of HO is confirmed to prevent ankylosing of joints.
  • Absolute treatment consists of surgical resection of mature bone once the HO has fully matured. This can be 12 to 18 months after the initial presentation.
  • Surgical consultation with an orthopaedic surgeon is warranted only if there will be an improvement in function as demonstrated by mobility, transfers, hygiene, and ADLs.
  • Indomethacin and etidronate are also used to help arrest bone formation in HO, but efficacy in the traumatic brain injury population has not been clearly proven (see below).
  • The most effective treatment option in the TBI population is surgical resection. In the SCI population, the most effective Non-Steroidal Anti-Inflammatory Drugs (NSAID) treatment regiments are either Rofecoxib 25 mg per day for 4 weeks or indomethacin 75 mg daily for 3 weeks.[1]

Medications[edit | edit source]

The two types of medications shown to have both prophylactic and treatment benefits are as follows:

  1. Non-Steroidal Anti-Inflammatory Drugs (NSAIDS)
    Indomethacin (two-fold action)
    • Inhibition of the differentiation of mesenchymal cells into osteogenic cells (direct)
    • Inhibition of post-traumatic bone remodelling by suppression of prostaglandin-mediated response (indirect) and anti-inflammatory properties
  2. Biphosphonates: Three-fold action
    • Inhibition of calcium phosphate precipitation
    • Slowing of hydroxyapatite crystal aggregation
    • Inhibition of the transformation of calcium phosphate to hydroxyapatite.

Surgical Interventions[edit | edit source]

The two main goals of surgical intervention are to

  1. Alter the position of the affected joint
  2. Improve its range of motion (ROM).[13]


Rehabilitation Post-Operatively: It is recommended that a rehabilitation program should start within the first 24 hours after surgery. The program should last for 3 weeks to prevent adhesion.[12]

Prognosis[edit | edit source]

Complications of heterotopic ossification present itself through decreased function and mobility, peripheral nerve entrapment, and pressure ulcers.

  1. Up to 70% of cases involving HA are asymptomatic.
  2. Ankylosis, vascular compression, and lymphedema can also be complications manifested in HO.
  3. Prognosis is generally good after surgery. Mean time from injury to surgery is 3.6 years. Once the surgery is performed, studies have shown that average ROM in the hip can improve from 24.3 to. After surgery, improvement was maintained in follow up 6 months after surgery. Complications from surgical resection of HO, such as infection, severe hematoma, and DVT[1]


In the case of sporting myositis ossificans, usually athletes are able to progress to light activity at 2 to 3 months, full activity by 6 months, and back to their pre-injury level by 1 year.[10]

Physical Therapy Management[edit | edit source]

Physical therapy has been shown to benefit patients suffering from heterotopic ossification. Pre-operative PT can be used to help preserve the structures around the lesion. ROM exercises (PROM, AAROM, AROM) and strengthening will help prevent muscle atrophy and preserve joint motion.

Clinical Note: Caution must be taken when working with patients with known heterotopic lesions. Therapy which is too aggressive can aggravate the condition and lead to inflammation, erythema, haemorrhage, and increased pain.

Post-operative rehabilitation has also shown to benefit patients with recent surgical resection of heterotopic ossification. The post-op management of HO is similar to pre-op treatment but much more emphasis is placed on edema control, scar management, and infection prevention. Calandruccio et al. outlined a rehabilitation protocol for patients who underwent surgical excision of heterotopic ossification of the elbow. The phases of rehab and goals for each phase are as follows:[3]

Phase I (Week 1)[edit | edit source]

Elbow Heterotopic Ossification

Goals:

  1. Prevent infection
  2. Protect and decrease stress on surgical site
  3. Decrease pain
  4. Control and decrease edema
  5. ROM to 80% of affected joint
  6. Maintain ROM of joint proximal and distal to surgical site

Phase II (2-8 Weeks)[edit | edit source]

Goals:

  1. Reduce ain
  2. Manage Edema
  3. Encourage limited ADL performances
  4. Promote Scar Mobility and proper remodeling
  5. Promote full ROM of affected joint
  6. Encourage quality muscle contractions
    Photo courtesy of prosportscare.com

Phase III (9-24 Weeks)[edit | edit source]

Goals:

  1. Self-manage Pain
  2. Prevent flare-up with functional activities
  3. Improve Strength
  4. Improve ROM (if still limited)
  5. Return to previous levels of activity 

References[edit | edit source]

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Sun E, Hanyu-Deutmeyer AA. Heterotopic Ossification.Available: https://www.ncbi.nlm.nih.gov/books/NBK519029/(accessed 24.10.2021)
  2. ↑ Radiopedia HO Available: https://radiopaedia.org/articles/heterotopic-ossification(accessed 24.10.2021)
  3. ↑ 3.0 3.1 3.2 Hsu JE, Keenan MA. Current review of heterotopic ossification. UPOJ 2010; 20: 126-130.
  4. ↑ 4.0 4.1 4.2 Mavrogenis AF, Soucacos PN, Papagelopoulos PJ. Heterotopic Ossification Revisited. Orthopedics. 2011Jan;34(3):177.
  5. ↑ Dalury DF, Jiranek WA. The incidence of heterotopic ossification after total knee arthroplasty. Journal of Arthroplasty 2004; 19: 447-457.
  6. ↑ Shehab D, Elgazzar AH, Collier BD. Heterotopic ossification. Jour of Nuclear Medicine 2002; 43: 346-353.
  7. ↑ 7.0 7.1 Orthobullets HO Available: https://www.orthobullets.com/pathology/8044/heterotopic-ossification(accessed 24.10.2021)
  8. ↑ Firoozabadi R, Alton T, Sagi HC. Heterotopic Ossification in Acetabular Fracture Surgery. Journal of the American Academy of Orthopaedic Surgeons. 2017;25(2):117–24.
  9. ↑ 9.0 9.1 Bossche LV, Vanderstraeten G. Heterotopic ossification: a review. J Rehabil Med 2005; 37: 129-136.5. Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.
  10. ↑ 10.0 10.1 Devilbiss Z, Hess M, Ho GWK. Myositis Ossificans in Sport: A Review. Curr Sports Med Rep. 2018 Sep;17(9):290-295. doi: 10.1249/JSR.0000000000000515. PMID: 30204632. Available:https://pubmed.ncbi.nlm.nih.gov/30204632/ (accessed 25.10.2021)
  11. ↑ McCarthy EF, Sundaram M. Heterotopic ossification: a review. Skeletal Radiol 2005; 34: 609-619.
  12. ↑ 12.0 12.1 Foruria AM, Augustin S, Morrey BF, Sanchez-Sotelo Joaquin. Heterotopic Ossification After Surgery for Fractures and Fractures-Dislocations Involving the Proximal Aspect of the Radius or Ulna. The Journal of Bone and Joint Surgery, Incorporated. 2015May15;95-A(10):e66(1)-e66(7).
  13. ↑ Pape HC et al. Current concepts in the development of hetetrotopic ossification. Journ Bone and Joint Surg 2004; 86: 783-787.
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