Heterotopic Ossification Treatment & Management

Physical Therapy

The use of physical therapy (PT) in HO has long been controversial. Rossier and co-investigators noted occasional transverse microfractures on sections of HO that they thought might be caused by spasticity or by overly aggressive PROM.^[4] Since then, the debate between resting the joint and aggressive PROM has continued. In the literature, however, the developing consensus appears to be that aggressive PROM and continued mobilization, once acute inflammatory signs have subsided, are indicated, because they help to maintain ROM and (in more extensive HO) they may lead to the formation of a pseudarthrosis. Resting the joint appears more likely to lead to decreased ROM or to ankylosis.

During the acute inflammatory stage, the patient should rest the involved joint in a functional position, and the physical therapist should initiate gentle PROM as soon as possible. The role of continuous PROM machines has not been studied in this situation. For patients with incomplete SCI or head injuries, maintaining ROM may be difficult because of pain from ROM exercises. The use of joint manipulation has been reported in patients with HO who, because of limited joint ROM, have functional limitations. However, such manipulation is controversial owing to the risk of the formation of new hematoma and because of the chance that long-bone fracture will occur in patients with secondary osteoporosis.

Nonarticular complications of HO are rare, but they have been reported. These complications include ulnar nerve compression with HO at the elbow, vascular (predominantly venous) compression with or without associated deep venous thrombosis (DVT), and lymphatic obstruction leading to lymphedema.^{[16, 17]}

• Prophylaxis

  • Although no effective protocol had previously been developed for preventing HO after SCI, the authors' studies, based on the well-documented beneficial effect of NSAIDs in the prevention of HO after total hip arthroplasty, showed that the following drugs can also be helpful in reducing the incidence and severity of HO after SCI^{[9, 18, 19, 20, 21]} :
    • The nonselective NSAID indomethacin SR prescribed for 3 weeks in a dose of 75 mg/d, after SCI, reduced the incidence of HO by 2-3 times.
    • A 25 mg/d prescription of the selective COX-2 inhibitor rofecoxib decreased the risk of HO formation by 2.5 times.
  • These positive results with NSAIDs in the prevention of HO may be an important step forward in the clinical management of this condition.

Once HO has developed to the point that it interferes significantly with the functional capacity of the patient, the only treatment option remaining is surgery, which most commonly is required at the hip.^[3] Ensure that the HO has reached maturity before resection, because resection of immature HO leads to recurrence rates of nearly 100%. Hemorrhage may be a significant problem at the time of surgery, with an average blood loss of 2100 mL reported. Postsurgical infection may lead to amputation; therefore, great care must be taken at the time of surgery. Initiate a presurgery program to eliminate any possible nidus of bacteremia or infections (eg, decubitus ulcers, urinary tract infections).

The usual surgical technique used on HO occurring anteriorly at the hip is anterior wedge resection. Postoperatively, position the joint properly with foam wedges so that the surgical correction can be maintained and any strain on the incision or pressure sores can be prevented. Start gentle PROM about 72 hours postoperation, and increase therapy intensity gradually to incorporate retraining in functional activities. Patient selection and careful identification of functional goals are critical for successful surgical intervention.

Consultation with an orthopedist is necessary for any consideration of surgical management of HO.

• Radiation therapy^{[3, 22, 23]}

  • Radiation therapy has been studied mostly in connection with the prevention of HO in patients at high risk for recurrence following hip arthroplasty.
  • The most common use in the rehabilitation setting is for the prevention of postoperative recurrence, but the optimal dosage, frequency, and timing have not been established.
  • Mesenchymal stem cells that may be in muscle and that transform into bone-forming cells are highly radiosensitive. Little is known of radiation therapy's effect on HO after SCI when it is used as a primary treatment. One reason that radiation therapy has not been established as a treatment for HO is a risk of local induction of malignancy. However, radiation has been used in Europe by Sautter-Bihl and colleagues as a primary treatment for early HO after SCI; no adverse effects were noted.^[24]