Heterotopic Ossification Treatment & Management

Medical therapy

Palovarotene was the first drug approved for fibrodysplasia ossificans progressiva (FOP). A gain-of-function mutation in the BMP type I receptor activin receptor–like kinase-2 (ALK2 [ACVR1]) drives abnormal bone formation, including HO, in patients with FOP. Palovarotene, an orally bioavailable retinoic acid receptor (RAR) agonist, has particular selectivity at the gamma subtype of RAR. [12]

The basis for the drug’s approval was 18-month data from the phase-3, multicenter, open-label MOVE trial, with palovarotene leading to a 54% reduction in annualized HO volume. [11]

Radiation therapy

Radiation therapy has been studied mostly in connection with the prevention of HO in patients at high risk for recurrence following hip arthroplasty. [19, 46, 47, 48, 49]

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. [50]

Extracorporeal shock wave therapy

Studies by Reznik et al of 11 patients indicated that extracorporeal shock wave therapy can reduce pain and increase ROM in neurogenic HO. The patients, all of whom had chronic HO at the hip or knee as a complication of TBI, had significant pain reduction, as measured by the Wong-Baker FACES Pain Rating Scale. In addition, flexion and functional reach improved for the knee in these patients, although significant ROM improvements were not seen for the hip. [51, 52]