A Multicenter Study to Evaluate Functional Outcome After Knee Replacement

A Prospective, Multicenter Study to Evaluate Functional Outcome After Knee Replacement

Patients will be consecutively enrolled by implant. Implant groups will be those who have undergone surgery with either a ConforMIS iTotal® CR TKA or an Off-the- Shelf (OTS) system.

The patient will conduct functional testing and answer questionnaires.

The results will compare the ConforMIS iTotal with an Off the Shelf Knee replacement.

Study Overview

• Status: Terminated
• Conditions: Osteoarthritis
• Intervention / Treatment: Device: ConforMIS iTotal Knee Replacement; Device: Off the Shelf Total Knee Replacement

Detailed Description

To compare functional and patient reported outcome data for a consecutively enrolled group of subjects who have undergone surgery with either a ConforMIS iTotal® CR TKA or an Off-the- Shelf (OTS) system.The person conducting the functional testing will be blinded to the device implanted. Sites will perform the off-the-shelf total knees conventional instrumentation.

• Study Type: Interventional
• Enrollment (Actual): 215
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • La Jolla, California, United States, 92037
      • University of California in San Diego
    • San Diego, California, United States, 92123
      • Sharp HealthCare
  • Colorado
    • Parker, Colorado, United States, 80134
      • Denver-Vail Orthopedics
  • Connecticut
    • New Haven, Connecticut, United States, 06520
      • Yale School of Medicine
  • Massachusetts
    • Boston, Massachusetts, United States, 02111
      • Tufts University
  • Missouri
    • Columbia, Missouri, United States, 65212
      • University of Missouri
  • New York
    • Albany, New York, United States, 12205
      • OrthoNY
  • Ohio
    • Cincinnati, Ohio, United States, 45219
      • The Lindner Center for Research and Education

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion:

• Clinical condition included in the approved Indications For Use for the iTotal CR
• Osteoarthritis, as confirmed by the investigator's assessment of disease status at screening visit that warrants a TKR procedure. Disease status is assessed by Clinical and Radiographic assessment
• Willingness to participate in the clinical study, to give informed consent and to attend all follow-up visits
• > 18 years of age

Exclusion:

• Subject will require a simultaneous bilateral procedure
• Other lower extremity surgery within 1 year
• Severe (> 15º) fixed valgus or varus deformity
• Severe (> 15º) extension deficit
• Severe instability due to advanced loss of osteochondral structure
• Loss of bone or musculature, osteoporosis, neuromuscular or vascular compromise in the area of the joint to be operated on to an extent that the procedure is unjustified
• Insufficient bone stock on the femoral or tibial surfaces
• Contralateral knee replacement surgery within the past 6 months
• BMI > 40
• Active malignancy (defined as a history of any invasive malignancy - except non-melanoma skin cancer), unless patient has been treated with curative intent and there have been no clinical signs or symptoms of the malignancy for at least 5 years
• Poorly controlled diabetes (defined as HbA1c >7 or surgeon discretion)
• Immunocompromised
• Other physical disability affecting the hips, spine, or contralateral knee that limits function
• Disabling chronic pain with narcotic dependence
• Compromised PCL or collateral ligament
• Prior history of failed implant surgery of the joint to be treated, including Unicompartmental Knee Arthroplasty (UKA), or Bicompartmental Knee Arthroplasty (BKA)
• Prior history of failed high tibial osteotomy (HTO)
• Participation in another clinical study which would confound results
• Inability to complete the protocol in the opinion of the clinical staff due to safety or other reasons

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: Single

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: ConforMIS iTotal Knee replacement; iTotal patient-specific knee replacement system	Device: ConforMIS iTotal Knee Replacement; A knee replacement performed with patient specific implant and surgical jigs.
Active Comparator: DePuy total knee replacement; Off the shelf knee replacement system	Device: Off the Shelf Total Knee Replacement; A knee replacement system by DePuy, Zimmer, Biomet, Smith & Nephew, or Stryker
Active Comparator: Zimmer total knee replacement; Off the shelf knee replacement system	Device: Off the Shelf Total Knee Replacement; A knee replacement system by DePuy, Zimmer, Biomet, Smith & Nephew, or Stryker
Active Comparator: Biomet total knee replacement; Off the shelf knee replacement system	Device: Off the Shelf Total Knee Replacement; A knee replacement system by DePuy, Zimmer, Biomet, Smith & Nephew, or Stryker
Active Comparator: Smith & Nephew total knee replacement; Off the shelf knee replacement system	Device: Off the Shelf Total Knee Replacement; A knee replacement system by DePuy, Zimmer, Biomet, Smith & Nephew, or Stryker
Active Comparator: Stryker total knee replacement; Off the shelf knee replacement system	Device: Off the Shelf Total Knee Replacement; A knee replacement system by DePuy, Zimmer, Biomet, Smith & Nephew, or Stryker

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional Activities Subscale Score Within the Knee Society Score (KSS) Measure	Comparing the functional testing differences between iTotal and off the shelf. "Total Functional Activities Score" - a subscale within the Knee Society Score (KSS) with its individual subscale score. The Total Functional Activities Score subscale interprets the functional knee health of each patient via a series of tests such as walking/standing (30 points), standard activities (30 points), advanced activities (25 points), and sports/recreational activities (15 points). Deductions to score are made for factors that limit a patient's mobility, such as needing to use an ambulatory device. The subscale scoring system ranges from 0-100, with higher scores indicating better knee function.	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient Satisfaction Subscale Score Within the Knee Society Score (KSS) Measure	Measuring and comparing the differences between iTotal and off the shelf knees with patient reported outcomes. "Patient Satisfaction", a subscale within the Knee Society Score (KSS), was utilized to capture this metric. The Patient Satisfaction subscale combines scores given for certain responses (very satisfied, satisfied, neutral, somewhat dissatisfied, very dissatisfied) across 5 questions. These questions are designed to determine the level of satisfaction a patient has with their implant across both everyday and active activities. This score ranges from 0-40, with higher scores indicating higher levels of patient satisfaction.	1 year
Incidents of Major Procedure-related and Device Related Complications (Including Revision Rates)	All complications were stratified according to clinicaltrials.gov reporting standards and each site labeled each complication as either device-related, non-device-related, procedure-related, and non-procedure-related.	1 year

Collaborators and Investigators

• Sponsor: Restor3D
• Investigators: Principal Investigator: Mary O'Connor, MD, Yale University

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2015
• Primary Completion (Actual): November 16, 2022
• Study Completion (Actual): November 16, 2022

Study Registration Dates

• First Submitted: May 28, 2015
• First Submitted That Met QC Criteria: July 9, 2015
• First Posted (Estimated): July 10, 2015

Study Record Updates

• Last Update Posted (Estimated): November 21, 2025
• Last Update Submitted That Met QC Criteria: November 10, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: total knee replacement; knee replacement; knee implant
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis
• Other Study ID Numbers: 12-005

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes