NCT03838978

Calypso Knee System Clinical Study, OUS

Completed NA Results posted Last updated 10 April 2025

What this trial tests

NA trial testing Calypso Knee System (Implantable Shock Absorber) in Osteoarthritis, Knee in 81 participants. Completed in 14 March 2025.

Timeline

8 February 2019

Primary endpoint
17 January 2022

14 March 2025

Quick facts

Lead sponsor	Moximed
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	na
Design	single group
Masking	none
Primary purpose	treatment
Enrollment	81
Start date	8 February 2019
Primary completion	17 January 2022
Estimated completion	14 March 2025
Sites	5 locations across Belgium, Poland

Drugs / interventions tested

• Calypso Knee System (Implantable Shock Absorber)

Conditions studied

• Osteoarthritis, Knee — all drugs for Osteoarthritis, Knee →

Sponsor

Moximed

Who can join

Adults 25 to 65, any sex, with Osteoarthritis, Knee. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Percentage of Participants With Composite Clinical Success (CCS) Primary · From baseline to 24 months

A subject is considered a Composite Clinical Success (CCS), at 24 months, if the subject meets all of the following: 1. Clinically significant improvement of at least 20% from baseline on the WOMAC pain questions in the KOOS Knee questionnaire with a change of ≥10 points 2. Clinically significant improvement of at least 20% from baseline on the WOMAC function questions in the KOOS Knee questionnaire with a change of ≥10 points 3. Freedom from the following device-related serious adverse events: * Deep infection requiring surgical intervention (Both arms) * Damage to adjacent neurovascu

Group	Value	95% CI
Calypso Knee System	83.5
High Tibial Osteotomy (HTO)	57.2

Time to Full Weight Bearing (Days) Secondary · Through study completion (number of days to full weight bearing)

Group	Value	95% CI
Calypso Knee System	13.4	± 10.12
High Tibial Osteotomy (HTO)	58	± 39.91

WOMAC Pain Percent Change to Month 3 Secondary · From baseline to 3 months

The Knee Injury and Osteoarthritis Outcome Score (KOOS) Knee Survey includes the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) in its complete and original format (with permission), and WOMAC scores can be calculated from the KOOS Knee questionnaire. The response to each question is summed and the resultant scores are transformed to a 0-100 scale. A WOMAC score of zero (0) represents no knee problems and one hundred (100) represents extreme knee problems.

Group	Value	95% CI
Calypso Knee System	-55.5	± 29.3
High Tibial Osteotomy (HTO)	-33.4	± 35.8

WOMAC Pain Percent Change to Month 24 Secondary · From baseline to 24 months

The Knee Injury and Osteoarthritis Outcome Score (KOOS) Knee Survey includes the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) in its complete and original format (with permission), and WOMAC scores can be calculated from the KOOS Knee questionnaire. The response to each question is summed and the resultant scores are transformed to a 0-100 scale. A WOMAC score of zero (0) represents no knee problems and one hundred (100) represents extreme knee problems.

Group	Value	95% CI
Calypso Knee System	-76.0	± 28.2
High Tibial Osteotomy (HTO)	-64.7	± 33.0

WOMAC Function Percent Change to Month 3 Secondary · From baseline to 3 months

The Knee Injury and Osteoarthritis Outcome Score (KOOS) Knee Survey includes the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) in its complete and original format (with permission), and WOMAC scores can be calculated from the KOOS Knee questionnaire. The response to each question is summed and the resultant scores are transformed to a 0-100 scale. A WOMAC score of zero (0) represents no knee problems and one hundred (100) represents extreme knee problems.

Group	Value	95% CI
Calypso Knee System	-52.2	± 32.0
High Tibial Osteotomy (HTO)	-25.2	± 37.0

WOMAC Function Percent Change to Month 24 Secondary · From baseline to 24 months

The Knee Injury and Osteoarthritis Outcome Score (KOOS) Knee Survey includes the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) in its complete and original format (with permission), and WOMAC scores can be calculated from the KOOS Knee questionnaire. The response to each question is summed and the resultant scores are transformed to a 0-100 scale. A WOMAC score of zero (0) represents no knee problems and one hundred (100) represents extreme knee problems.

Group	Value	95% CI
Calypso Knee System	-73.9	± 29.6
High Tibial Osteotomy (HTO)	-58.8	± 35.8

Adverse events — posted to ClinicalTrials.gov

Time frame: Index procedure (enrollment) through 24 months (790 days). Reporting threshold: 5%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Calypso Knee System

Serious: 18/81 (22%)

Deaths: 0/81

High Tibial Osteotomy (HTO)

Serious: 39/81 (48%)

Deaths: 0/81

Serious adverse events (18 terms)

Reaction	System	Calypso Knee System	High Tibial Osteotomy (HTO)
Pain: Pain	Musculoskeletal and connective tissue disorders	—	—
Infection: Deep	Infections and infestations	—	—
Other: Other, bone consolidation	Musculoskeletal and connective tissue disorders	—	—
Anesthesia Complications: Other	Musculoskeletal and connective tissue disorders	—	—
Discomfort: Catching or pulling sensations	Musculoskeletal and connective tissue disorders	—	—
Discomfort: Inability to perform certain tasks	Musculoskeletal and connective tissue disorders	—	—
Swelling: Swelling	Musculoskeletal and connective tissue disorders	—	—
Infection: Cellulitis	Infections and infestations	—	—
Infection: Superficial incisional surgical site	Infections and infestations	—	—
Hospital readmission: Removal of implant due to dissatisfaction	Musculoskeletal and connective tissue disorders	—	—
Nerve injury	Musculoskeletal and connective tissue disorders	—	—
Scar formation: Other	Musculoskeletal and connective tissue disorders	—	—
Scar formation: Periprosthetic adhesions/fibrosis	Musculoskeletal and connective tissue disorders	—	—
Wound: Other	Musculoskeletal and connective tissue disorders	—	—
Wound: Wound dehiscence (post-explant)	Musculoskeletal and connective tissue disorders	—	—
Psychological event: Other	Psychiatric disorders	—	—
Bleeding: Hematoma	Vascular disorders	—	—
Thrombophlebitis: Superficial Thrombophlebitis	Vascular disorders	—	—

Other adverse events (2 terms — click to expand)

Reaction	System	Calypso Knee System	High Tibial Osteotomy (HTO)
Pain: Pain	Musculoskeletal and connective tissue disorders	—	—
Nerve injury	Musculoskeletal and connective tissue disorders	—	—

Most-reported serious reactions: Pain: Pain, Infection: Deep, Other: Other, bone consolidation, Anesthesia Complications: Other, Discomfort: Catching or pulling sensations, Discomfort: Inability to perform certain tasks, Swelling: Swelling, Infection: Cellulitis.

Data from ClinicalTrials.gov NCT03838978 adverse events section.

Sponsor's own description

A study to evaluate the safety and effectiveness of the Calypso Knee System when used in subjects with symptomatic osteoarthritis of the medial compartment of the knee.

Publications & conference data

2 peer-reviewed publications reference this trial (live from Europe PMC):

1. Implantable Shock Absorber Provides Superior Pain Relief and Functional Improvement Compared With High Tibial Osteotomy in Patients with Mild-to-Moderate Medial Knee Osteoarthritis: A 2-Year Report.
   Diduch DR, Crawford DC, Ranawat AS, Victor J, et al · · 2023 · cited 9× · PMID 36823955 · DOI 10.1177/19476035231157335
2. Improved 2-Year Freedom from Arthroplasty in Patients with High-Risk SIFK Scores and Medial Knee Osteoarthritis Treated with an Implantable Shock Absorber versus Non-Operative Care.
   Pareek A, Parkes CW, Gomoll AH, Krych AJ. · · 2023 · cited 6× · PMID 37198901 · DOI 10.1177/19476035231154513