Link Between Clinical Predictors of Heterotopic Ossification and Histological Analysis in Combat-Injured Service Members.
BACKGROUND
Heterotopic ossification (HO) is a debilitating condition that occurs following traumatic injury and may restrict range of motion and delay rehabilitation. The timing and efficacy of surgical resection have varied widely, and there is a gap in knowledge between clinical predictors of HO recurrence and histological analysis.


METHODS
Thirty-three service members seen at Walter Reed National Military Medical Center for symptomatic HO were enrolled in an institutional review board-approved study. Participants took oxytetracycline on four scheduled days prior to HO resection to determine the mineral apposition rate (bone growth rate).


RESULTS
Detailed histological analyses included scanning electron microscopy with backscattered electron imaging and light microscopy. Data indicated that the mineral apposition rate of trauma-induced HO was approximately 1.7 μm/day at the time of operative intervention, which was 1.7 times higher than the rate in non-pathological human bone. The mineral apposition rate and postoperative alkaline phosphatase values were demonstrated to be positively and significantly related (ρ = 0.509, p = 0.026, n = 19). When the analysis was limited to patients with no more than a two-year period from injury to excision (thereby removing outliers who had a longer time period than their counterparts) and traumatic brain injury and nonsteroidal anti-inflammatory drugs (known correlates with HO development) were controlled for in the statistical analysis, the mineral apposition rate and recurrence severity were significantly related (ρ = -0.572, p = 0.041, n = 11).


CONCLUSIONS
Data demonstrated a link between benchtop research and bedside care, with the mineral apposition rate elevated in patients with HO and correlated with recurrence severity; however, a larger sample size and more clinical factors are needed to refine this model.


METHODS
Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland The Center for Rehabilitation Sciences Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, Maryland brad.isaacson.ctr@usuhs.edu.
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Isaacson
Departments of Orthopaedics (B.K.P.) and Rehabilitation (P.F.P.), Walter Reed National Military Medical Center, Bethesda, Maryland Department of Surgery, Uniformed Services University of Health Sciences, Bethesda, Maryland.
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Potter
Bone & Joint Research Laboratory, Department of Veterans Affairs, Salt Lake City, Utah Departments of Bioengineering and Biology, University of Utah, Salt Lake City, Utah.
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Bloebaum
Bone & Joint Research Laboratory, Department of Veterans Affairs, Salt Lake City, Utah.
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Epperson
Bone & Joint Research Laboratory, Department of Veterans Affairs, Salt Lake City, Utah.
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Kawaguchi
The Center for Rehabilitation Sciences Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, Maryland.
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Swanson
The Center for Rehabilitation Sciences Research, Department of Physical Medicine & Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, Maryland Departments of Orthopaedics (B.K.P.) and Rehabilitation (P.F.P.), Walter Reed National Military Medical Center, Bethesda, Maryland.
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Pasquina
D000328:Adult; D016723:Bone Remodeling; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel; D009999:Ossification, Heterotopic / Q000209:etiology / Q000473:pathology* / Q000601:surgery*; D011379:Prognosis; D011446:Prospective Studies; D000067398:War-Related Injuries / Q000150:complications