Femoral Neuropathy due to Heterotopic Ossification in the Iliopsoas
65-year-old male with anoxic brain injury due to cardiac arrest who presented for acute rehabilitation. On admission, he was found to have left lower extremity pain and weakness with 1/5 strength in hip flexors and knee extensors. An electrodiagnostic study revealed active denervation of left femoral nerve innervated muscles and no voluntary motor unit potentials in the rectus femoris and iliopsoas. Findings were suggestive of localized peripheral neuropathy of left femoral nerve. Imaging revealed potential heterotopic ossification (HO) in the left iliopsoas muscle and was confirmed with a triple phase bone scan. He was treated with IV pamidronate, vitamin D supplementation and calcium level monitoring.
HO is a common complication of trauma, spinal cord injury, or traumatic brain injury. This is an unusual case where HO affected the iliopsoas in the area of the femoral nerve, resulting in a focal neuropathy with active denervation. During inpatient rehabilitation, the patient had prompt diagnostic workup and treatment with intravenous bisphosphonates. His therapy regimen was modified to focus on physiological functional activities along with avoidance of resistance exercises and electrical stimulation, so as not to interfere with axonal regeneration and peripheral sprouting. Outpatient evaluation three months post-radiological diagnosis revealed improvement to 3/5 left hip flexion and 1/5 knee extension strength. The patient was able to ambulate at close supervision level with a dual channel MAFO and an anterior floor reaction component to prevent buckling. Repeat electrodiagnostic studies are pending.
This case highlights an unusual presentation of heterotopic ossification in the region of the iliopsoas as a cause of focal femoral neuropathy in the setting of anoxic brain injury. It is important for providers to recognize the value of prompt diagnostic workup as well as appropriate pharmacologic and therapeutic treatment in an interdisciplinary setting.
David Oh– Resident Physician, Temple University Hospital | MossRehab
Esther Yoon– Resident Physician, Temple University Hospital | MossRehab
Chad Metzger– Resident Physician, Temple University Hospital | MossRehab
Paul Chan– Resident Physician, Temple University Hospital | MossRehab
Miriam Segal– Attending Physician, MossRehab
Channarayapatn Sridhara– Clinical Director, Electrodiagnostic Laboratory, MossRehab