Heterotopic Ossification Circumferentia Articularis (HOCA) of Both Knee Joints After Guillain-Barré Syndrome.

Heterotopic ossification (HO) is the abnormal development of bone within soft tissue. It is a frequent complication after traumatic as well as atraumatic central nervous system (CNS) insult. It has rarely been found to be associated with Guillain-Barré syndrome (GBS). Only a few cases of HO associated with GBS have been reported so far in medical literature. We present a 30-year-old female patient with severe bilateral knee stiffness following axonal polyneuropathy type of GBS that developed 10 months ago in her immediate post-partum period. She was put on mechanical ventilation for two weeks. She was diagnosed as HO based on clinical and radiological studies. This is an extremely unusual presentation of HO encircling both the knees following GBS without any other well-known risk factors. We have coined a new nomenclature-Heterotopic Ossification Circumferentia Articularis (HOCA)-for this type of presentation. In our patient, various factors such as prolonged ICU stay, mechanical ventilation, hypoxia, and long-standing hypomobility could be attributed to the development of this severe form of HO.