Heterotopic Ossification – Bones Gone Awry
One of the dreaded complications of trauma and surgery, heterotopic ossification (HO) can cause significant discomfort for patients. This process creates bone where there should be none – in muscle, soft tissue, tendons, ligaments, skin, muscle, fascia, or virtually in any part of connective tissue. HO is also called ectopic bone.
In the image associated with this blog, the x-ray shows left hip hardware surrounded by excessive bone.
HO develops when a tissue injury sets off a cascade of inflammatory cells that activate a bone creation program. Certain types of injuries carry a higher risk of HO: up to 40% of hip arthroplasties, up to 30% of bone fractures or dislocations, up to 50% of spinal cord injuries, up to 20% of severe burns and up to 90% of severe traumatic amputations. Heterotopic Ossification: A Comprehensive Review (nih.gov). Patients with strokes and traumatic brain injuries are also at risk for HO developing in connective tissue.
The knees, elbows, hips and shoulders are most commonly affected. This syndrome of abnormal bone development may start as soon as 3 weeks or up to 12 weeks after the initial musculoskeletal, spinal cord injury or other event. As first signs, the patient experiences a general loss of joint mobility and function. Other symptoms include swelling, pain, heat, redness, palpable mass, and contracture formation. X-rays and ultrasounds detect the condition. Heterotopic Ossification – Physiopedia (physio-pedia.com)
Healthcare providers manage HO by first trying to prevent it and then trying to treat it to improve symptoms and function. Low dose radiation is used to prevent HO by irradiating the patient 24 hours before surgery or up to 72hours afterwards. Some providers question the efficacy of this treatment.
Nonsteroidal anti-inflammatory drugs are commonly used to prevent HO but carry risks of creating gastrointestinal side effects. Celecoxib (a COX-2selective inhibitor) shows promise for being able to significantly reduce the incidence of HO.
Once the abnormal bone is fully mature, in about 6 months, surgery offers benefits to improve function in patients with significant symptoms such as pain, painful motion, restricted motion, or prominent bone that can lead to pressure sores or impaired hygiene. The surgeon cuts off the excess bone, in a procedure that carries a high degree of risk. The bone may encase major neurovascular structures, which may be injured during surgery. Heterotopic Ossification: A Comprehensive Review (nih.gov)
Surgery is the wrong approach if the patient has a genetic cause of HO; surgery may worsen the condition. Genetic causes include fibrodysplasia ossificans progressive and progressive osseous heteroplasia. Abnormal Excess Bone Growth in Heterotopic Ossification (verywellhealth.com)
HO remains a poorly understood, difficult to prevent and debilitating complication from trauma. Its symptoms add to the misery of the injured patient, and its surgical treatment carries its own risks, adding to the patient’s pain and suffering.
Kimm Ebersole, MHA, RN
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