Compartment Syndrome of the Thigh in a Patient with Fibrodysplasia Ossificans Progressiva

INTRODUCTION: The severe pain that commonly accompanies appendicular flare-ups of fibrodysplasia ossificans progressiva (FOP) is often ascribed to compartment syndrome, but no documentation exists. CASE REPORT: We revisited the case of an adult with classic FOP who underwent measurement of compartment pressure of the thigh during an acute, severely painful flare-up of the thigh. The intracompartmental pressure of the thigh was measured at 95-–110 mm of mercury (normal compartment pressure is 0-–8 mmHg). A fasciotomy of the thigh was performed. Despite immediate post-operative relief of pain, progressive heterotopic ossification and loss of function of the hip and knee occurred. CONCLUSION: This unique case documents and confirms the suspected presence of compartment syndrome during an acute flare-up of FOP and has vital implications for understanding the pathophysiology and care of patients with acute appendicular flare-ups of FOP and for the design of emerging clinical trials.