Answers
1) This is AP view of femur. The whole femur bone is not visualized.
- Present of implants with characteristic of implant failure (area of hypodensity around the femoral head, formation of new bone around the prosthetic joint)
- Periosteal reaction (sunray)
- Sinus formation surrounded with calcification of the soft tissue
- Mixture of sclerotic and lytic area over the whole femur bone.
- Sequestreum
2) The provisional diagnosis based on short history and radiological findings is Chronic osteomyelitis of the left femur with implant failure.
3) Investigation
Blood investigation (FBC, Blood C&S, ESR)
Sinogram (can lozalized focus of infection)
Bone scan can reveals hidden foci of inflammatory foci but rarely needed.
4) Component of Implant failure
Infection (Early vs. late)
Loosening
Fractured of prosthesis or bending
Dislocation of prosthesis
New bone formation around the prosthesis.
**Mechanical failure
Plastic failure (devised failed to maintain original shape)
Fatigue failure (due to repetitive loading on a devise)
Brittle failure (caused by defect in design or metallurgy)
4) Management for this patient
- Treat the infection with prolong course of antibiotic
- Dressing over the sinus to provide comfort to patient as the discharge could be very irritated.
- The dead bone could be excised and external fixator can be put. However, decision should be made for the beneficial of the patient. Old age, chronic infection, and the extension of the lesion make this choice a very bad decision for this patient. Therefore, conservative management is the best for this patient.
- Bed ridden patient may cause formation of sacral sore and deep vein thrombosis. Therefore, patient should be encourage to sit, frequent turning of the position or the usage of specialized air bed (ripple mattress) and limb exercise and physiotherapy
- Elderly patient who presented with fracture should also be started on osteoporosis treatment.
- Eye assesment is crucial as impaired sight could be the reason the patient having trauma in the first place.
- Metastatic bone disease should also be excluded.
- Since bacteria from chronic OM can be dormant and occasionally release into the blood stream, therefore it should be treated. (the most common bacteria associated with implant is staphylococcus epidermidis)