Proximal tibial resorption in a modern total knee prosthesis

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Radiology

Background:

• Cobalt chromium alloys are increasingly used in total knee arthroplasty to reduce polyethylene wear.
• Thicker cobalt chromium designs may increase stress shielding and bone resorption.
• This study investigates proximal tibial bone resorption with a modern total knee design.

Purpose of the Study:

• To determine the incidence of proximal tibial bone resorption after total knee arthroplasty (TKA).
• To identify patient and implant characteristics associated with bone resorption.
• To evaluate the early clinical and radiographic outcomes of TKA with a specific implant design.

Main Methods:

• A consecutive series of 339 primary TKAs were reviewed over a 24-month period.
• Preoperative and postoperative radiographs were analyzed using a novel classification system for resorption.
• Patient demographics, preoperative alignment, and implant characteristics were correlated with resorption incidence.

Main Results:

• Proximal tibial bone resorption was observed in 35.1% of knees.
• Resorption was significantly associated with male gender and preoperative varus alignment.
• Most resorption was mild (Grade 1) and diagnosed within 7 months postoperatively.

Conclusions:

• Proximal tibial resorption is a frequent finding with this TKA implant, particularly in specific patient groups.
• Early bone resorption typically remodels and stabilizes, but long-term clinical significance is uncertain.
• Further research is needed to understand the impact of resorption on long-term implant survivorship.