Investigating the incidence and magnitude of heterotopic ossification with and without joints involvement in patients with a limb fracture and mild traumatic brain injury
Article [Version of Record]
Abstract(s)
Objectives: This study seeks to evaluate the incidence rate of heterotopic ossification (HO) formation in patients
afflicted by an isolated limb fracture (ILF) and a concomitant mild traumatic brain injury (mTBI).
Methods: The current study is an observational study including ILF patients with or without a concomitant mTBI
recruited from an orthopedic clinic of a Level 1 Trauma Hospital. Patients were diagnosed with a mTBI according
to the American Congress of Rehabilitation Medicine (ACRM) criteria. Radiographs taken on average 3 months
post-trauma were analyzed separately by two distinct specialists for the presence of HO proximally to the
fracture site (joints or extra joints). Both raters referred to Brooker's and Della's Valle's classification to establish
signs of HO. First, analyses were conducted for the full sample. Secondly, a matched cohort was used in order to
control for specific factors, namely age, sex, type of injury, and time elapsed between the accident and the
analyzed radiograph.
Results: The full sample included a total of 183 patients with an ILF (94 females; 47.5 years old), of which 50 had
a concomitant mTBI and 133 without. Radiographic evidence of HO was significantly higher in patients with an
ILF and a mTBI compared to ILF patients (X2 = 6.50; p = 0.01). The matched cohort consisted of 94 participants
(i.e.; 47 patients from the ILF + mTBI group and 47 patients from the ILF group). Again, ILF + mTBI patients
presented significantly higher rates of HO signs in comparison to ILF patients (X2 = 3.69; p = 0.04). Presence of
HO was associated with prolonged delays to return to work (RTW) only in ILF + mTBI patients (F = 4.055;
p = 0.05) but not in ILF patients (F = 0.823; p = 0.37).
Conclusions: Study findings suggest that rates of HO are significantly higher proximally to fracture sites when ILF
patients sustain a concomitant mTBI, even after controlling for factors known to influence HO. Moreover, results
show that HO is associated with a prolonged RTW only in ILF patients with a concomitant mTBI but not in ILFonly patients. The impact of mTBI on HO formation warrants further attention to detect early signs of HO, to
identify shared physiopathological mechanisms and, ultimately, to design targeted therapies.