Medacta GMK Sphere® vs. Medacta GMK PS Post-Market Outcomes Study

NCT03391323 | Completed FDA Device

• 1 other identifier: SJRC-GMK
• Study Type: interventional
• Target: 218
• Locations: 1 country
• Sites: 1

Brief Summary

The study is a prospective, randomized comparison of total knee arthroplasty with the Medacta GMK Sphere® knee compared to the Medacta GMK PS knee, with comparison to data from previous trials of similar study design.

Conditions

Joint Disease; Osteoarthritis; Osteoarthritis, Knee

Outcome Measures

Primary Outcomes (1)

• Forgotten Joint Score (FJS)

  The average Forgotten Joint Score (FJS) of those patients receiving the Medacta GMK Sphere® knee prosthesis will be compared with the average FJS of those receiving the Medacta GMK PS knee prosthesis. The FJS total score range is 0-100, with higher scores indicating a higher degree of "forgetting" the artificial joint, that is, a lower degree of awareness.

  Change from baseline at 2 years and 5 years post-operative

Secondary Outcomes (3)

• Total Knee Society Score (KSS)

  Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative

• Lower Extremity Activity Scale (LEAS)

  Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative

• Radiographic Analysis

  Pre-operative, 6 weeks, 6 months, 1, 2, 3, 4, and 5 years post-operative

Study Arms (2)

Medacta GMK Sphere® Medial-Pivot Knee Prosthesis

OTHER

Research subjects in this arm received GMK Sphere.

Device: Medacta GMK Sphere® Medial-Pivot Knee Prosthesis

Medacta GMK PS Posterior Stabilized Knee Prosthesis

OTHER

Research subjects in this arm received GMK PS.

Device: Medacta GMK PS Posterior Stabilized Knee Prosthesis

Interventions

Medacta GMK Sphere® Medial-Pivot Knee Prosthesis DEVICE

Medacta GMK Sphere® Medial-Pivot Knee Prosthesis

Medacta GMK PS Posterior Stabilized Knee Prosthesis DEVICE

Medacta GMK PS Posterior Stabilized Knee Prosthesis

Eligibility Criteria

• Age: 21 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients willing to sign the Informed Consent.
• Patients able to comply with follow-up requirements including postoperative weight bearing restrictions and self-evaluations.
• Male and non-pregnant female patients ages 21 - 80 years of age at the time of surgery.
• Patients requiring a primary total knee replacement.
• Patients with a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or avascular necrosis (AVN).
• Patients with intact collateral ligaments.

You may not qualify if:

• Patients with inflammatory arthritis.
• Patients that are morbidly obese, body mass index (BMI) \> 40.
• Patients with a history of total or unicompartmental reconstruction of the affected joint.
• Patients with neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device.
• Patients with a systemic or metabolic disorder leading to progressive bone deterioration.
• Patients that are immunologically compromised, or receiving chronic steroids (\>30 days), excluding inhalers.
• Patients bone stock is compromised by disease or infection, which cannot provide adequate support and/or fixation to the prosthesis.
• Patients with knee fusion to the affected joint.
• Patients with an active or suspected latent infection in or about the knee joint.
• Patients whose surgery will utilize computer-assisted surgical navigation (CAOS) techniques.
• Patients whose surgery will utilize minimally invasive surgical techniques.
• Patients that are prisoners.

Sponsors & Collaborators

• David F. Scott, MD: lead
• Medacta USA: collaborator

Study Sites (1)

Spokane Joint Replacement Center

Spokane, Washington, 99218, United States

Location

MeSH Terms

Conditions

Osteoarthritis; Osteoarthritis, Knee; Joint Diseases

Condition Hierarchy (Ancestors)

Arthritis; Musculoskeletal Diseases; Rheumatic Diseases

Study Officials

• David Scott, MD

  Spokane Joint Replacement Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: December 11, 2017
• First Posted: January 5, 2018
• Study Start: April 1, 2015
• Primary Completion: November 27, 2023
• Study Completion: November 27, 2023
• Last Updated: April 29, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)