Microstructural analysis and biomechanical impact of myositis ossificans: A cadaveric case report

Abstract

Introduction: Myositis ossificans (MO) is a benign, ossifying, self-limited lesion that most commonly occurs in limb musculature secondary to trauma and may cause pain, stiffness, pressure sores, or decreased range of motion. The purpose of this study is to perform microstructural analysis of myositis ossificans and determine the biomechanical impact on the adductor longus (AL) muscle. Materials and methods: In situ radiographic imaging was performed prior to additional dissection, visualization, measurement, and photography of the AL and MO. Subsequently, the MO was removed for micro-computed tomography and histological analysis. Tissue parameters were used to calculate physiological cross-sectional area (PCSA) and maximal isometric force (Fmax) of the AL and determine the functional impact of the MO on the AL. Results: On in situ imaging, the MO appeared radio-dense along its perimeter and lucent at its core. AL morphology and attachments were typical. MO microarchitecture parameters and histology revealed low bone volume; decreased structural integrity; and lamellar bone formation with mature osteocytes, lacunae, and functional osteons. The MO occupied approximately 25.79% of the AL and decreased AL's Fmax from 112.726 N to 83.654 N and torque on the femur from 972.221 N·cm to 721.486 N ​cm. Conclusions: The combination of gross, radiographic, histomorphometric, histological, and biomechanical findings suggest a mature MO traumatica resulting in a functional deficit of the AL. This report may benefit healthcare providers evaluating soft tissue masses as well as bone and mineral scientists and medical educators when presented with similar research or educational cases.

Keywords

• Myositis ossificans
• Heterotopic ossification
• Micro-CT
• Biomechanics
• Adductor longus
• Bone histopathology