Peri-implant Fractures

Peri-implant fractures are fractures that occur in the presence of an orthopaedic implant such as plates, screws, intramedullary nails, or joint prostheses. These fractures may occur either adjacent to the implant or through the bone segment containing the implant. They are becoming increasingly common due to the widespread use of orthopaedic implants and the aging population.

Peri-implant fractures pose significant challenges for orthopaedic surgeons because the presence of hardware alters the biomechanics of the bone and complicates fracture fixation. Management requires careful evaluation of implant stability, bone quality, fracture pattern, and patient factors.

The primary goals of treatment are restoration of limb alignment, stable fixation of the fracture, and preservation of the existing implant if it remains functional.

A peri-implant fracture is defined as a fracture that occurs in the vicinity of a previously inserted orthopaedic implant. These fractures may occur at the tip of implants, around screw holes, or through areas weakened by previous surgery.

• Fractures adjacent to plates or screws
• Fractures near intramedullary nails
• Fractures around joint prostheses
• Fractures through stress risers created by implants

Peri-implant fractures occur due to a combination of mechanical and biological factors. Implants can create stress concentrations in the bone, predisposing it to fracture under load.

• Stress concentration at implant ends
• Osteoporosis
• Trauma or fall
• Fatigue failure of bone
• Implant loosening or failure

Orthopaedic implants alter the distribution of mechanical stress within bone. This may create areas of stress shielding and stress concentration.

• Stress shielding leads to bone resorption
• Implant ends create stress risers
• Screw holes weaken cortical bone
• Long plates may produce stress concentration at plate ends

These biomechanical factors increase the risk of fractures around implants, particularly in osteoporotic bone.

• Pain at site of previous implant
• Swelling and deformity
• Loss of limb function
• Difficulty bearing weight

Patients often present after a fall or minor trauma, particularly in elderly individuals with osteoporotic bone.

• Plain radiographs of affected bone
• Full-length radiographs to assess implant
• CT scan for complex fracture patterns

Radiographic evaluation should assess fracture pattern, implant integrity, and bone quality.

Treatment of peri-implant fractures depends on multiple factors including fracture location, implant stability, and bone quality.

• Assess stability of existing implant
• Restore limb alignment
• Provide stable fixation
• Preserve bone stock

• Nonunion
• Implant failure
• Malalignment
• Infection
• Delayed union

• Avoid stress risers
• Use appropriate implant length
• Optimize bone quality
• Careful surgical technique

• Fractures occur around existing implants
• Stress risers at implant ends increase fracture risk
• Management depends on implant stability
• Long plates often used to bridge fracture