iAssist vs. Conventional Instrumentation in Total Knee Arthroplasty

Evaluation of Zimmer® iASSIST™ vs. Conventional Instrumentation in Total Knee Arthroplasty: Radiographic, Clinical and Economic Outcomes

The purpose of this prospective study is to evaluate Zimmer® iASSIST™ with respect to radiographic, clinical and economic outcomes and compared to conventional instrumentation in primary total knee arthroplasty (NexGen or Persona knee implants).

Study Overview

• Status: Completed
• Conditions: Knee Osteoarthritis; Avascular Necrosis; Post-traumatic; Arthrosis
• Intervention / Treatment: Procedure: total knee arthroplasty

Detailed Description

The study design is a prospective, multicenter, comparative outcome study. The study requires each site to obtain IRB (Institutional Review Board) approval prior to study enrollment. All potential study subjects will be required to participate in the Informed Consent Process.

All study subjects will undergo preoperative clinical evaluations prior to their total knee arthroplasty. Investigators will collect clinical data for 12 months. Follow-up clinical visits include 3 and 12 months post-operatively.

The primary endpoint of this study is defined as component alignment as determined using long leg X-Rays. The secondary endpoint will be to evaluate the Knee Society Score, EQ-5D (EuroQol-5Dimensions) scoring system, operating room time, blood loss and complications

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Malaga, Spain, 29007
    • Hospital El Angel, S.A.
  • Palma de Mallorca, Spain, 07010
    • Hospital Unviersitario Son Espases
• Switzerland
  • Zurich, Switzerland, 8008
    • Universitätsklinik Balgrist

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patient is male or female
• Patient needs a primary total knee replacement using the NexGen LPS Flex or Persona knee implant
• Patient is diagnosed with non-inflammatory degenerative joint disease (e.g., osteoarthritis, post-traumatic arthritis, avascular necrosis, etc.)
• Patient is over 18 years old

• Patient is able to:

  • Understand what participation in the study entails and willing to consent (patient or his/her legal guardian) to participate in the study by signing and dating an IRB/EC (ethics committee) approved inform consent form, and
  • Follow surgeon/staff instructions, and
  • Return for all follow-up evaluations, and
  • Able and willing to undergo a preoperative full-leg, standing radiographs and/or CT-scan
• Patient meets an acceptable preoperative medical clearance and is free of or treated for cardiac, pulmonary, hematological or other conditions that would pose excessive operative risk.
• Patient has a presence of varus or valgus deformity of 15 degrees or less.

Exclusion Criteria:

• Patient is currently enrolled in an investigational new drug or device study.
• Patient has an active infection (including septic knee, distant infection, or osteomyelitis).
• Patient has severe hip arthrosis.
• Patient has neurological disorders (including, but not limited to Parkinson's disease).
• Patient has had a prior ipsilateral unicompartmental knee arthroplasty, TKA, knee fusion or patellectomy.
• Patient has hip or knee ankylosis.
• Patient has inflammatory joint disease.
• Patient has rheumatoid knee arthritis.
• Patient has indications of intra- and/or extra-articular deformations that would eliminate or tend to eliminate adequate implant support or prevent the use of an appropriately sized implant, such as polio, history of tibial plateau fracture, etc.
• Patient has any metal within 150 mm of the joint line for the operative-side knee.
• Patient has knee deformities greater than 15 degrees of fixed varus, valgus, or flexion contracture on initial physical examination.
• Female who is pregnant or lactating.
• Patient currently involved in any personal injury litigation, medical-legal or worker's compensation claims.
• Patient has arterial disease or stents that would exclude the use of a tourniquet.
• Patient has insufficient quality or quantity of bone to support the implant due to prior knee surgery (or surgeries), cancer, metabolic bone disease, osteoporosis/osteopenia (diagnosed or treated with medication), active/old/remote infection, etc.
• Patient has a mental condition that may interfere with his/her ability to give an informed consent or interfere with his/her ability or willingness to fulfill the requirements of the study.
• Patient has a condition that would place excessive demands on the implant (e.g., Charcot's joints, muscle deficiencies, multiple joint disabilities, skeletal immaturity, etc.).
• Patient has collateral ligament insufficiency.
• Patient has an immunosuppressive disorder (e.g., AIDS, etc.) that would require cytotoxic drugs, corticosteroids, large dose of irradiation, or antilymphocytic serum.
• Patient has an existing condition that would, in the opinion of the investigator, compromise participation or follow-up in this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: iAssist group; patients will have primary total knee arthroplasty with the iAssist. The iAssist Knee System is a computer assisted stereotaxic surgical instrument system to assist the surgeon in the positioning of orthopedic implant system components intra-operatively. It involves surgical instruments and position sensors to determine alignment axes in relation to anatomical landmarks and to precisely position alignment instruments and implant components relative to these axes.	Procedure: total knee arthroplasty; surgical procedure in which damaged parts of the knee joint are replaced with an implant.
Other: conventional instrumentation; patients will have primary total knee arthroplasty with the conventional instrumentation.	Procedure: total knee arthroplasty; surgical procedure in which damaged parts of the knee joint are replaced with an implant.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Component Alignment	Assess the differences in component alignment, measured by the mean of radiographs, between iASSIST™ and conventional instrumentation in primary total knee arthroplasty (TKA) procedures.	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knee Society Score Assessment	Assess the differences in Knee Society Score between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor	1 year
Knee Society Score Function	Knee Society Score function asses 12 months postoperatively between iASSIST™ and conventional instrumentation in primary TKA procedures. Higher (and better) score value: 100, lower value: 0. Score 80-100 = Excellent Score 70-79 = Good Score 60-69 = Fair Score below 60 = Poor	1 year
EQ-5D Questionnaire	Assess the differences in EQ-5D between iASSIST™ and conventional instrumentation in primary TKA procedures at 12 months postoperatively. Comparison of the derived EQ-5D scale and health state between the 2 groups. The EQ-5D questionnaire includes five dimensions (5D): mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. EQ-5D values range from -0.2 to 1 where the negative values correspond to bad health states (states worse than death), and 1.0 corresponds to perfect health.	1 year

Collaborators and Investigators

• Sponsor: Zimmer, GmbH
• Investigators: Study Director: Paola Vivoda, Ass.Direct, Zimmer Biomet

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2014
• Primary Completion (Actual): December 1, 2018
• Study Completion (Actual): December 1, 2018

Study Registration Dates

• First Submitted: April 6, 2017
• First Submitted That Met QC Criteria: April 6, 2017
• First Posted (Actual): April 12, 2017

Study Record Updates

• Last Update Posted (Actual): April 13, 2021
• Last Update Submitted That Met QC Criteria: March 18, 2021
• Last Verified: March 1, 2021

More Information

Terms related to this study

• Keywords: primary total knee arthroplasty
• Additional Relevant MeSH Terms: Pathologic Processes; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Arthritis; Osteoarthritis; Osteoarthritis, Knee; Necrosis
• Other Study ID Numbers: CSE2012-05K

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: No