TerminatedNCT00966979PKRUpdated Sep 13, 2023Results posted

Triathlon® Partial Knee Replacement (PKR) Outcomes Study

An interventional study of Triathlon PKR in Arthroplasty, Replacement, Knee, sponsored by Stryker Orthopaedics. Terminated at 9 sites in 4 countries. Open to participants aged 21 Years to 75 Years. Per ClinicalTrials.gov, last updated 2023-09-13.

Sponsored by Stryker Orthopaedics · Not applicable, Interventional, and Treatment

Why this study was terminated

Enrollment goals not being met.

Phase: Not applicable
Study type: Interventional
Enrollment: 111
Allocation: Not applicable
Ages: 21 Years to 75 Years
Sex: All

Study summary

The purpose of this study is to compare the 10-year Knee Society Score (KSS) functional results of the Triathlon PKR Unicondylar Knee to the 10-year Knee Society Score (KSS) functional results of the Triathlon Cruciate Retaining (CR) Total Knee.

Conditions studied

Arthroplasty, Replacement, Knee

Keywords

Osteoarthritis, Post-traumatic arthritis

In context

Lead sponsor

Stryker Orthopaedics is the lead sponsor of 44 studies on the registry; 1 is open to participants now.

Of its 5 completed or terminated interventional studies of FDA-regulated products, 5 (100%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 21 Years to 75 Years
Sexes eligible: All
Accepts healthy volunteers: No

Inclusion criteria

The subject is a male or non-pregnant female 21-75 years of age at the time of enrollment.
The subject requires a primary cemented unicompartmental knee replacement.
The subject has a diagnosis of osteoarthritis (OA) or posttraumatic arthritis (TA).
The subject has clinically intact cruciate and collateral ligaments and no ligamentous instability is present.
The subject has less than 10 degrees of flexion contracture and greater than 90 degrees of flexion.
The subject's preoperative mechanical alignment is less than 15 degrees of varus and 15 degrees of valgus.
The subject has signed the Institutional Review Board (IRB) approved study specific Informed Patient Consent Form.
The subject is willing and able to comply with postoperative scheduled clinical and radiographic evaluations and rehabilitation.

Exclusion criteria

Exclusion Criteria:

The subject has inflammatory arthritis or avascular necrosis(AVN).
The subject is obese, BMI > 35.
The subject has a history of total or unicompartmental (contralateral compartment and/or patellofemoral joint) reconstruction of the affected joint.
The subject has a history of anterior cruciate ligament (ACL) reconstruction.
The subject has had a high distal femoral, or proximal tibial osteotomy.
The subject has a mental, neuromuscular or neurosensory disorder, which would create an unacceptable risk of prosthesis instability, prosthesis fixation failure, or complications in post-operative care and/or limit the ability to assess the performance of the device.
The subject has a systemic or metabolic disorder leading to progressive bone deterioration that the surgeon feels would affect the overall outcome of the study.
The subject is immunologically suppressed, or is receiving chronic steroids (>30 days duration).
The subject has a known sensitivity to device materials.
The subject's bone stock is compromised by disease and/or infection which cannot provide adequate support and/or fixation to the prosthesis.
The subject's bone stock is compromised by a prior implantation which cannot provide adequate support and/or fixation to the prosthesis.
The subject has an active or suspected latent infection in or about the knee joint.
The subject is a prisoner.

Study design

Phase: Not applicable
Primary purpose: Treatment
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrollment: 111 participants (actual)

Study arms

Other
Triathlon PKR
All subjects enrolled will receive the Triathlon PKR device.
Device: Triathlon PKR

Interventions

DeviceTriathlon PKR
Triathlon PKR is a unicondylar knee resurfacing system designed to replace a single osteoarthritic compartment of a patient's natural knee.

What researchers measure

Primary outcomes

Investigation of Clinical Performance and Patient Outcome With the Functional Knee Society Score (KSS).
The Knee Society Score (KSS) consists of two distinct sub-scores: one for pain, range of motion, joint stability and alignment (Pain/Motion KSS) and one for distance walked, stair climbing and walking aids (Functional KSS). This outcome measure was only for the KSS Function Score at 10-years. The KSS Function score subscale is 0-100, with 100 representing a better outcome. Although the specific scores are not distinguished as "excellent", "good", "fair", or "poor", a higher value represents a better outcome.
Time frame: 10 years

Secondary outcomes

10-years Kaplan Meier Survival Analysis
For the purpose of this study the Kaplan-Meier survival curves are a statistical method to estimate the survival function from lifetime data of a knee replacement after treatment. Survivorship is defined as a percentage of knees free of any component revision for any reason.
Time frame: 10-years

Results

Posted Sep 13, 2023

Limitations and caveats

After 13-years the enrollment goal was not met. This led to a protocol amendment to include retrospective cases. These cases were combined with the initial prospective cases and followed prospectively for the planned observation time. This study does not compare prospective to retrospective cases. The retrospectively enrolled cases were followed prospectively and there were no retrospective cases that reached the 10-year time point, only 12 prospective cases had 10-year data.

Participant flow

There were 112 knees in 111 patients that were enrolled in the study (one bilateral case).

Participant flow — Overall Study
Milestone	Triathlon PKR Unicompartmental Knee
Started	111
Completed	13
Not completed	98
Withdrew: Death	1
Withdrew: Lost to follow-up	6
Withdrew: Withdrawal by subject	14
Withdrew: Adverse event	5
Withdrew: Sponsor terminated early	49
Withdrew: Censored because surgery not done	2
Withdrew: Censored because study device was not implanted	14
Withdrew: Censored because of inclusion/exclusion violation	7

Outcome measures

PrimaryInvestigation of Clinical Performance and Patient Outcome With the Functional Knee Society Score (KSS).

The Knee Society Score (KSS) consists of two distinct sub-scores: one for pain, range of motion, joint stability and alignment (Pain/Motion KSS) and one for distance walked, stair climbing and walking aids (Functional KSS). This outcome measure was only for the KSS Function Score at 10-years. The KSS Function score subscale is 0-100, with 100 representing a better outcome. Although the specific scores are not distinguished as "excellent", "good", "fair", or "poor", a higher value represents a better outcome.

Time frame:: 10 years
Reported as:: Mean · units on a scale

Investigation of Clinical Performance and Patient Outcome With the Functional Knee Society Score (KSS).
units on a scale	Triathlon PKR Unicompartmental Knee
Investigation of Clinical Performance and Patient Outcome With the Functional Knee Society Score (KSS).	98.33 ± 5.77

Secondary10-years Kaplan Meier Survival Analysis

For the purpose of this study the Kaplan-Meier survival curves are a statistical method to estimate the survival function from lifetime data of a knee replacement after treatment. Survivorship is defined as a percentage of knees free of any component revision for any reason.

Time frame:: 10-years
Reported as:: Number · percentage of knees

10-years Kaplan Meier Survival Analysis
percentage of knees	Triathlon PKR Unicompartmental Knee
10-years Kaplan Meier Survival Analysis	91.35 (80.12 to 96.37)

Adverse events

Collected over This study required that all operative site adverse events, regardless of seriousness, and serious systemic events, be reported from enrollment to the 10-year postoperative time interval.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
Operative Adverse Events	0/89 (0%)	11/89 (12.4%)	26/89 (29.2%)
Non-Operative Adverse Events	1/88 (1.1%)	20/88 (22.7%)	0/88 (0%)

Most frequent serious events

Most frequent serious events
Event	Operative Adverse Events	Non-Operative Adverse Events
Operative siteMusculoskeletal and connective tissue disorders	10/89	—
Non-operativeCardiac disorders	—	6/88
Non-operativeNeoplasms benign, malignant and unspecified (incl cysts and polyps)	—	4/88
Non-operativeGastrointestinal disorders	—	3/88
Non-operativeGeneral disorders	—	2/88
Non-operativeRenal and urinary disorders	—	2/88
Non-operative sitePsychiatric disorders	—	1/88
Non-operativeRespiratory, thoracic and mediastinal disorders	—	1/88
Non-operativeVascular disorders	—	1/88
Operative siteInjury, poisoning and procedural complications	1/89	—

Most frequent other events

Most frequent other events
Event	Operative Adverse Events	Non-Operative Adverse Events
OperativeMusculoskeletal and connective tissue disorders	26/89	0/88

Baseline characteristics

Age, Continuous
Age, Continuous(years)	Triathlon PKR
Mean	61.83 (44 to 76)

Sex: Female, Male
Sex: Female, Male(Participants)	Triathlon PKR
Female	39
Male	49

Race (NIH/OMB)
Race (NIH/OMB)(Participants)	Triathlon PKR
American Indian or Alaska Native	1
Asian	1
Native Hawaiian or Other Pacific Islander	0
Black or African American	0
White	86
More than one race	0
Unknown or Not Reported	0

Study locations

9 sites

Heekin Orthopaedic Institute for Research, Inc.
Jacksonville, Florida 32204, United States
Rothman Institute
Egg Harbor Township, New Jersey 08234, United States
Department of Orthopaedic Surgery, Kaleida Health, Buffalo General Hospital
Buffalo, New York 14203, United States
Syracuse Orthopedic Specialists
Syracuse, New York 13214, United States
Rothman Institute
Media, Pennsylvania 19063, United States
Mansfield Orthopaedics
Morrisville, Vermont 05661, United States
Praxisklinik Stollberg und Arthro. Zentrum GmbH
Stollberg, 09366, Germany
Presidlo Ospedaliero Civile Santi Antonio e Biagio
Alessandria, 15100, Italy
Hassleholm Sygehus Ortopaedkirurgisk afd. Esplanadgatan
Hässleholm, Sweden

References and documents

Study documents

Protocol, analysis plan and consent form · Sep 26, 2019

Documents are hosted by the registry — open the source record to download them.

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Sep 13, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT00966979
Lead sponsor: Stryker Orthopaedics
Responsible party: Sponsor
First posted: Aug 27, 2009
Start date: Jan 2010
Primary completion: Sep 2022
Completion: May 2023
Results posted: Sep 13, 2023
Last update: Sep 13, 2023

Study contacts

R. David Heekin, M.D.

principal investigator · St. Vincent's Medical Center

Marco Tinius, MD

principal investigator · Praxisklinik Stollberg

Marco Schiraldi, MD

principal investigator · Presidlo Ospedaliero Civile Santi Antonio e Biagio

Brian Aros, MD

principal investigator · Mansfield Orthopaedics

Fabio Orozco, MD

principal investigator · Rothman Institute

Matthew Phillips, MD

principal investigator · Department of Orthopaedic Surgery, Kaleida Health, Buffalo General Hospital

Peter Bonutti, MD

principal investigator · Bonutti Clinic

Soren Toksvig-Larsen, MD

principal investigator · Hassleholm Sygehus Ortopaedkirurgisk afd.

Brett Greenky, MD

principal investigator · Syracuse Orthopedic Specialists

Paul Jacob, MD

principal investigator · Oklahoma Sports Science and Orthopaedics

Oversight

Data monitoring committee: No

View the source record on ClinicalTrials.gov ↗

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