42 year old male with 8 month history of vague hip pain bilaterally. Previous severe motor vehicle accident.
42 year old male patient with 8 month history of vague hip pain bilaterally. Previous history of motor vehicle accident.
The plain radiographs and CT images demonstrate extensive new bone formation around both hip joints. The new bone abuts both neurovascular bundles, but does not encase them. The MRI images demonstrate increased signal within the new bone indicating the presence of marrow. Heterotopic ossification occurs in approximately 20% of patients with severe spinal injury. It is more common following injuries of the cervical or upper thoracic cord. The soft tissue calcification occurs within months of the injury with bone maturation taking over a year to develop. The aetiology is unknown but there are recognised associations with thrombosis of Batsons plexus and with pressure sores. Symptoms include decreased range of movement and compression of the neurovascular bundle from the new bone. Treatment is aimed at maintaining movement and in cases of significant neurovascular compromise, surgical resection of the new bone may be required.
Heterotopic Ossification
1. Large areas of newly formed bone tissue are visible around both hip joints. Their density is significantly higher than the surrounding soft tissues, presenting as either regular or irregular patchy calcifications.
2. CT shows that the newly formed bone tissue is extensive, extending from the soft tissues around the pelvis. Part of it is connected to the original bone cortex, and clear bone density can be observed.
3. On MRI, high-signal areas (equivalent to normal bone marrow signal) are visible within the newly formed bone, indicating the presence of a medullary cavity or bone marrow component in this newly formed bone.
4. The newly formed bone tissue is adjacent to, but does not completely encase, the major neurovascular bundles on both sides.
5. The patient has a history of a severe traffic accident and has experienced discomfort in both hips for the past 8 months, consistent with a gradual process of ossification within soft tissues.
1. Heterotopic Ossification (HO)
- Etiology: Commonly seen in patients with a history of severe trauma, spinal cord injury, or burns.
- Imaging characteristics: Bone-like structures appearing within soft tissues around injured muscle groups or joints, in continuity with normal bone or in focal distribution. CT/MRI may reveal mature bone tissue and bone marrow signals.
- Clinical relevance: May lead to decreased joint mobility, pain, or symptoms of neurovascular compression.
2. Tumorous or Tumor-like Lesions (e.g., osteosarcoma, chondrosarcoma, etc.)
- Although newly formed bone or calcification can be observed on imaging, there is usually evident invasive change and cortical bone destruction.
- In this case, the multiple ectopic and symmetrical new bone formations, along with the history of trauma, are more indicative of heterotopic ossification.
3. Chronic Periosteal Proliferation or Cartilage Calcification
- Various degrees of soft tissue calcification may be seen in rheumatic or other joint diseases, but large-scale ossification of this type is relatively rare.
- Based on the MRI findings of bone marrow signal and the patient’s medical history, this type of lesion is less likely.
Considering the history of major trauma, the onset of bilateral hip dysfunction and pain over the past few months, and the imaging findings of mature new bone forming around the joints, the most consistent diagnosis is Heterotopic Ossification (HO). If necessary, additional serological tests (e.g., alkaline phosphatase, inflammatory markers) or a biopsy during surgery can be performed to confirm the diagnosis.
1. Treatment Strategy
- Conservative treatment: In the early stage, consider nonsteroidal anti-inflammatory drugs (NSAIDs) or ossification-inhibiting agents (e.g., bisphosphonates) to slow the progression of heterotopic ossification.
- Physical therapy and rehabilitation: Maintain and improve joint range of motion as much as possible, avoiding exacerbation of pain or risk of fracture.
- Surgical intervention: When newly formed bone significantly limits joint movement or causes neurovascular compression, consider surgical removal. Ideally, surgery should be performed after the ossification has relatively matured (usually one year after injury) to reduce the risk of recurrence.
2. Rehabilitation and Exercise Prescription (FITT-VP Principle)
- Frequency: 3–5 times per week, adjustable based on pain and tolerance of joint mobility.
- Intensity: Low to moderate intensity; subjective perception should remain in the “mild-to-moderate” fatigue range.
- Time: 20–30 minutes each session. Splitting sessions is possible, for example twice a day for 15 minutes each.
- Type: Range of motion exercises, low-load resistance training, lower limb stretching, and mobility training that do not induce severe pain. Hydrotherapy or assistive devices can help reduce joint stress.
- Volume: Aim for a total of 90–150 minutes of exercise per week, increasing gradually based on individual progress.
- Progression: As tolerance and joint mobility improve, gradually increase load or session duration while closely monitoring symptom changes.
3. Precautions
- Avoid excessive stretching or forceful activities to prevent fractures or further soft tissue injury.
- If significant neurological symptoms (e.g., radiating pain, numbness) or vascular compression signs (e.g., cold extremities, color changes) occur, seek medical attention promptly.
- Regularly evaluate imaging and clinical status to dynamically assess the maturity of heterotopic ossification and changes in joint function.
Disclaimer: This report serves as a reference analysis and cannot replace in-person consultation or professional medical advice. Specific diagnoses and treatment plans should be based on the patient’s actual condition and comprehensive evaluation by specialist physicians.
Heterotopic Ossification
