Fractures After Total Knee Replacement
Fracture occurring around a Knee which has undergone Total Knee Replacement are called Periprosthetic Fractures. Although not very commonly seen, Fractures in a prosthetic Knee have been reported in international literature. Fractures of Femur, Tibia and Patella can all occur following injury to the prosthetically replaced Knee.
Periprosthetic Fractures involving Femur
- Femoral notching done during the Total Knee Replacement
- Osteonecrosis of Femur
Anterior-Posterior views, lateral views and oblique views are all required.
Non-operative treatment is avoided, except in patients with excessive comorbidity. This may include traction or plaster cast.
The Fractures can be fixed by retrograde nailing of the Femur Fracture or by fixation with a plate and screws.
Periprosthetic Fractures involving the Tibia
These Fractures usually involve the Medial or Lateral Condyle of the Tibia.
X-rays: Anterior Posterior Views and Lateral Views
- No role of Conservative Management
- Removal of the original Tibia tray.
- Fixing a Fracture with screws and using bone graft if required.
- If the fragment cannot be fixed then a step cut is done for the Tibia and the step is replaced by metal wedge on the Tibial tray.
Periprosthetic Fracture involving the Patella
- Not leaving adequate Patella after shaving (Patella left behind is less than 12mm)
- Use of central pegged implant
- Devascularization of Patella after a lateral retinacular release
- Excessively thick Patella
- Component malalignment
Fracture may be missed if undisplaced
If strongly suspected Fracture due to anterior Knee Pain and not visible on X-ray.
Conservative Management: Indicated in the following
- Intact extensor mechanism
- Patellar component is in place
- No comminution
- Displacement is < 2 cm
Conservative management involves immobilization in a plaster cast from groin to ankle for a period of 6 weeks, after which Knee is mobilized with the help of continuous passive movement machine.
This involves partial or complete Patellectomy depending upon whether the component is in place.
Partial Patellectomy: If component is in place.
Complete Patellectomy : If component is loose.