Heterotopic ossification as rare complication of hemiplegia following stroke: two cases

Abstract

Background: Heterotopic ossification (HO), characterized by new bone formation in the periarticular regions of large joints, is frequently seen after spinal cord injury, traumatic brain injury, burn and trauma. It is a rare complication of hemiplegia following stroke, with a reported incidence of 1% or less.

Case reports: This study reports two unusual presentations of HO: (1) A 56-year-old male with a history of atrial fibrillation on warfarin developed sudden-onset left hemiplegia. Eight months after the event, he was diagnosed with HO of the hip joint including both the affected and unaffected sides. (2) A 55-year-old female with left hemiplegia due to subarachnoid bleeding developed HO on the left hip joint 7 months later. In both cases, spasticity around the hip muscle groups, especially hip flexors, adductors and knee extensors, and limited range of motion accompanied by pain were present. X-ray and pelvic computed tomography revealed HO around the hip joints. After 4 weeks of inpatient rehabilitation, the ranges of hip joint motion improved, without exceeding 10° in the direction of flexion and rotations, and ambulation levels were wheelchair-bound for the first case and dependent on a cane for the second case.

Conclusions: Considering the presented cases, it is suggested that HO should be kept in mind in the differential diagnosis in stroke patients presenting with spontaneous joint pain or limitation. The clinical importance of HO development on both the affected and unaffected sides in post-stroke hemiplegia is emphasized, since it may worsen the patient's functional status.