Total Knee Arthroplasty With the Medial-Pivot Knee System (MEDIAL-PIVOT)

Total Knee Arthroplasty With the Medial-Pivot Knee System: Clinicaland Radiological Outcomes at 9.5 Years' Mean Follow-up

The "ball-in-socket" design of the Medial-Pivot knee system (MicroPort Orthopedics, Arling-ton, Tennessee, USA) aims to reproduce normal knee kinematics by medializing its rotational axis. Thegoal of this study was to measure knee range of motion (ROM) with this implant after a mean follow-up of 10 years and to report the survivorship and long-term clinical and radiological outcomes. Wehypothesized the prosthetic knee would have at least 120◦flexion at 10 years. This was retrospective, single-centre study of 74 Medial-Pivot knees implanted in71 patients (average age of 69 years) between May 2005 and November 2007. All patients who receiveda Medial-Pivot knee were included consecutively. The mean follow-up was 10 years. Clinical and radio-logical assessments were performed using the Knee Society Score (KSS) and Ewald's score. Kaplan-Meirsurvival analysis was used to calculate survivorship.

Study Overview

• Status: Completed
• Conditions: Arthroplasty Complications

Detailed Description

methodsThis was retrospective, single-centre study of 74 Medial-Pivotknees implanted in 71 patients between May 2005 and Novem-ber 2007. During this period, several types of semi-constrainedprimary TKA implants were used.The "ball-in-socket" design of the Medial-Pivot knee system (MicroPort Orthopedics, Arling-ton, Tennessee, USA) aims to reproduce normal knee kinematics by medializing its rotational axis. Thegoal of this study was to measure knee range of motion (ROM) with this implant after a mean follow-up of 10 years and to report the survivorship and long-term clinical and radiological outcomes. Wehypothesized the prosthetic knee would have at least 120◦flexion at 10 years. This was retrospective, single-centre study of 74 Medial-Pivot knees implanted in71 patients (average age of 69 years) between May 2005 and November 2007. All patients who receiveda Medial-Pivot knee were included consecutively. The mean follow-up was 10 years. Clinical and radio-logical assessments were performed using the Knee Society Score (KSS) and Ewald's score. Kaplan-Meirsurvival analysis was used to calculate survivorship.

• Study Type: Observational
• Enrollment (Actual): 71

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

The patients were operated by four experienced surgeons usingthe same protocol. A mid-line skin incision was made in all patientsexcept one who had previously undergone a lateral osteotomy. The parapatellar arthrotomy was medial in all cases. Independent tibialand femoral cuts were made with an intramedullary femoral aim-ing device targeting 7◦valgus in 48 cases and 5◦in 2 cases. Femoral component external rotation of 3◦relative to the posterior condy-lar plane was applied in all patients. All implants were fixed usingPalacos®bone cement with gentamicin (Haeraus, Warsaw, USA).The patella was resurfaced in 40 knees.

Description

Inclusion Criteria:

• patients > 18 years
• patienst must be operated
• patient with mid-line skin incision

Exclusion Criteria:

• patients < 18 years

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Flexion with an Advance® Medial-Pivot knee	The objective of this study was to evaluate the flexion in patients with an Advance® Medial-Pivot knee after an average follow-upof 10 years. Knee flexion was measured with a goniometer in the office; thegreater trochanter, knee centre and lateral malleolus were used asreference points.	2years

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire, Amiens
• Investigators: Principal Investigator: Fabrice Mertl, MD, PhD, CHU Amiens

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2017
• Primary Completion (Actual): October 2, 2017
• Study Completion (Actual): October 2, 2017

Study Registration Dates

• First Submitted: September 18, 2018
• First Submitted That Met QC Criteria: September 18, 2018
• First Posted (Actual): September 19, 2018

Study Record Updates

• Last Update Posted (Actual): May 17, 2023
• Last Update Submitted That Met QC Criteria: May 16, 2023
• Last Verified: September 1, 2018

More Information

Terms related to this study

• Keywords: total knee arthroplasty; survivorship; kinematics; medial-pivot knee system
• Other Study ID Numbers: PI2017_843_0052

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