Analysis of Varus Collapse in Obese Patients With Stem and Non-Stem Tibial Components Following Primary Total Knee Arthroplasty (SvNS)

May 26, 2026 updated by: Jacob M. Elkins
The purpose of this study is to compare rates of varus collapse, aseptic loosening, and implant failure in female obese patients undergoing total knee arthroplasty (TKA) and will review the degree of influence of stemmed tibial components versus non-stemmed tibial components on varus collapse and aseptic loosening, a consequence of implant micromotion.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to identify varus collapse, aseptic loosening, and implant failure in female obese patients undergoing total knee arthroplasty (TKA). In addition, this study will review the degree of influence of stemmed tibial components versus non-stemmed tibial components on varus collapse and aseptic loosening, a consequence of implant micromotion.

Female patients age 40 and older with BMI of 35 kg/m2 and above will be randomized into two groups: the non-stem tibial component (control group) and the stem tibial component (treatment group). Previous studies done in the past in normal weight patients showed that there is little or no advantage in using the stem tibial implants over the non-stem ones. Theoretically, biomechanical studies have suggested that there may be improved fixation and load distribution with the use of stem tibial implants. Thus, it is necessary to see if there is any difference between both implant options among female patients who have the highest incidence of varus collapse. In terms of design, the stem tibial implants are slightly longer than the non-stem ones. They are designed to extends deeper into the tibia to enhance fixation and improve load distribution. The use of either stem tibial implants is usually based on patients' characteristics and surgeons' preference.

Following informed consent, standard perioperative patient-reported metrics will be collected (Knee Injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS-JR], American Knee Society score, and Patient-Reported Outcome Measurement Information System 10 [PROMIS-10]) before surgery and after surgery (2-3 weeks, 8-10 weeks, 1 year, 3 years, and 5 years). After surgery, study participants will receive routine surgical care which includes two knee radiographs at 8-10 weeks and one year. In addition to this, the study participants will be evaluated at 3 years, and 5 years postoperative periods where they will complete routine PROMs as listed above and have knee radiographs during each visit.

Study Type

Interventional

Enrollment (Actual)

54

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Iowa
      • North Liberty, Iowa, United States, 52317
        • Iowa Health Care Medical Center North Liberty

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Female adult patients with severe osteoarthritis scheduled to have primary total knee arthroplasty
  • Age 40 or older
  • 35 kg/m2 and above
  • Only patients from the PI's clinic will be included.
  • Women who are still menstruating and are currently on contraceptives and women who are in menopause.

Exclusion Criteria:

  • Patients who have some active local or widespread infection (including secondary or inflammatory osteoarthritis)
  • medical conditions that put them at risk of complications or death during and after the study would not be eligible for surgery
  • Patients with previous knee surgery on arthroplasty site will be excluded
  • Pregnant patients and women who are capable of getting pregnant

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Group A: Stemmed Tibial Implant
This study group will receive a stemmed tibial implant as part of their TKA.
Procedure: Total Knee Arthroplasty (TKA)
Both study arms will undergo TKA
Device: Stemmed Tibial Implant
A stemmed tibial implant.
Active Comparator: Group B: Non-Stemmed Tibial implant
This study group will receive a non-stemmed tibial implant as part of their TKA.
Procedure: Total Knee Arthroplasty (TKA)
Both study arms will undergo TKA
Device: Non-stemmed tibial implant
A non-stemmed tibial implant.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Varus Collapse
Time Frame: up to 5 years post surgery
The investigators will track rate of varus collapse.
up to 5 years post surgery
Aseptic loosening
Time Frame: up to 5 years post surgery
The investigators will track rates of aseptic loosening.
up to 5 years post surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Jacob M. Elkins

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 14, 2023

Primary Completion (Estimated)

December 31, 2032

Study Completion (Estimated)

December 31, 2032

Study Registration Dates

First Submitted

August 24, 2023

First Submitted That Met QC Criteria

August 30, 2023

First Posted (Actual)

August 31, 2023

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 26, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 202303366

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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