An Unusual Prepatellar Bursa Swelling: Patellar Button Dissociation and Migration

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Medical device technology

Background:

• Implant loosening and migration are known complications in arthroplasty.
• Patellar button complications, including loosening and fracture, have been documented.
• Extra-articular migration of patellar components is exceptionally rare.

Purpose of the Study:

• To report an extremely rare case of patellar button migration.
• To highlight a delayed complication following total knee arthroplasty.
• To discuss the implications of extra-articular implant migration.

Main Methods:

• Case report of a patient 11 years after total knee arthroplasty.
• Clinical examination and diagnostic imaging.
• Review of literature on patellar component complications.

Main Results:

• The patellar button migrated from its original position.
• The migrated button was located in the prepatellar bursa.
• This migration occurred 11 years after the initial total knee arthroplasty.

Conclusions:

• Extra-articular patellar button migration is a rare but possible complication.
• Delayed migration can occur long after primary total knee arthroplasty.
• Understanding such rare events is crucial for patient management and implant design.