Patellar impingement following unicompartmental arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Knee Biomechanics

Background:

• Patellofemoral complications are rarely reported after unicompartmental arthroplasty.
• Long-term consequences of these complications remain largely unknown.

Purpose of the Study:

• To analyze the incidence and long-term consequences of patellofemoral complications following unicondylar arthroplasty.
• To investigate the relationship between patellar complications and femoral component positioning.

Main Methods:

• Ninety-nine unicompartmental arthroplasties (74 medial, 25 lateral) in 80 patients were evaluated.
• Radiographic assessment for patellar impingement and osteoarthritis at an average of 14 years post-op.
• Clinical evaluation using Knee Society scores and patellofemoral symptom questionnaires for 77 unrevised knees at an average of 15 years post-op.

Main Results:

• 29 knees showed patellofemoral osteoarthritis, and 28 had patellar impingement.
• Patellar complications were associated with increased pain during stair negotiation and rising from a chair.
• Patellar impingement was more frequent after lateral arthroplasty and with anterior femoral component placement, leading to one revision.

Conclusions:

• Patellofemoral osteoarthritis and impingement are significant long-term complications after unicompartmental arthroplasty.
• These complications negatively impact functional outcomes, with impingement causing more severe symptoms and higher revision rates.
• Careful femoral component placement is crucial to minimize patellar impingement risk.