Review

Medial Stabilized Knee Replacement

A brief review of the design principles and performance in joint replacement registries.

Joseph Maratt, MD | August 30, 2020

During a knee replacement, the arthritic and damaged joint is resurfaced with metal and plastic implants.

There are over 150 different knee replacement implants on the market today. Many of their origins can be traced back to innovative designs from the 1970s. Traditional knee replacement designs can be grouped into 2 broad categories - ones that rely on a ligament within the knee and others that substitute for it with features like a cam and post.

The medial stabilized total knee design was introduced in the early 2000s to better reproduce the functional anatomy and more closely replicate the normal movement and stability of the knee.

medial stabilized design

Research shows that the medial side of the knee is more stable than the lateral. The medial stabilized designs attempt to mimic that asymmetric stability with the medial side more stable than the lateral.

These implants have shown good long-term outcomes along with better functional outcomes in several studies.

Registries can report the real world performance of implants across institutions and users in a region. They can provide valuable and actionable data to guide practice.

graph showing good survivorship of medial stabilized designs

A recent report of registry data showed that the medial stabilized knee replacement design has comparable survivorship to traditional designs despite the greater degree of constraint.

References:
  • The Early Innovators of Today‚Äôs Resurfacing Condylar Knees. Robinson et al.; JOA 2005.
  • Posterior Femoral Rollback in the Normal Knee from Full Extension to Full Flexion. Dennis; 2005.
  • The rationale for a total knee implant that confers anteroposterior stability throughout range of motion. Blaha; JOA 2004.
  • An 11- to 15-year clinical outcome study of the Advance Medial Pivot total knee arthroplasty: pivot knee arthroplasty. Karachalios et al.; BJJ 2016.
  • A Randomized Controlled Trial Comparing a Medial Stabilized Total Knee Prosthesis to a Cruciate Retaining and Posterior Stabilized Design: A Report of the Clinical and Functional Outcomes Following Total Knee Replacement. Dowsey et al.; JOA 2019.
  • A Single Surgeon Series Comparing the Outcomes of a Cruciate Retaining and Medially Stabilized Total Knee Arthroplasty Using Kinematic Alignment Principles. French et al.; JOA 2020.
  • Evaluation of the Medial Stabilized Knee Design Using Data From National Joint Registries and Current Literature. Cassar-Gheiti et al.; JOA 2020.

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About Dr. Maratt

Dr. Joseph Maratt is a board certified orthopaedic surgeon specialized in hip and knee replacement.

TKA

During this procedure, the damaged bone and cartilage of the knee is removed, and replaced with prosthetic implants.