Trial Outcomes & Findings for Calypso Knee System Clinical Study (NCT NCT03671213)

Last Updated: 2025-04-10

Results Overview

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 neurovascular or ligament structures necessitating reconstruction (Both arms) * Non-union (HTO only) 4. Maintenance of implant integrity as evaluated by radiographic assessment 5. Endpoint Subsequent Surgical Intervention (SSI)

Recruitment status

COMPLETED

Study phase

Target enrollment

81 participants

Primary outcome timeframe

From baseline to 24 months

Results posted on

2025-04-10

Participant Flow

The Calypso Clinical Study enrolled 81 subjects in the investigational (Calypso) arm. This study was compared to a historical control arm (HTO). The results presented include data from the historical control arm.

Participant milestones

Participant milestones
Measure	Calypso Knee System The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
Overall Study STARTED	81	81
Overall Study COMPLETED	73	65
Overall Study NOT COMPLETED	8	16

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Calypso Knee System Clinical Study

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Calypso Knee System n=81 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=81 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).	Total n=162 Participants Total of all reporting groups
Age, Continuous	51.2 years STANDARD_DEVIATION 7.71 • n=5 Participants	52.5 years STANDARD_DEVIATION 7.58 • n=7 Participants	51.8 years STANDARD_DEVIATION 7.65 • n=5 Participants
Sex: Female, Male Female	32 Participants n=5 Participants	28 Participants n=7 Participants	60 Participants n=5 Participants
Sex: Female, Male Male	49 Participants n=5 Participants	53 Participants n=7 Participants	102 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	3 Participants n=5 Participants	1 Participants n=7 Participants	4 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	78 Participants n=5 Participants	50 Participants n=7 Participants	128 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	30 Participants n=7 Participants	30 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race (NIH/OMB) White	80 Participants n=5 Participants	80 Participants n=7 Participants	160 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 Participants
Body Mass Index (BMI)	28.4 kg/m^2 STANDARD_DEVIATION 3.44 • n=5 Participants	29.3 kg/m^2 STANDARD_DEVIATION 4.36 • n=7 Participants	28.8 kg/m^2 STANDARD_DEVIATION 3.94 • n=5 Participants

PRIMARY outcome

Timeframe: From baseline to 24 months

Outcome measures

Outcome measures
Measure	Calypso Knee System n=81 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=81 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
Composite Clinical Success (CCS)	83.5 percentage of subjects	57.2 percentage of subjects

SECONDARY outcome

Timeframe: Through study completion (Number of days to full weight bearing)

Any subject that had evaluable data was deemed eligible for effectiveness evaluation and included in the analysis.

Outcome measures

Outcome measures
Measure	Calypso Knee System n=81 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=77 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
Time to Full Weight Bearing (Days)	13.4 days Standard Deviation 10.12	58 days Standard Deviation 39.91

SECONDARY outcome

Timeframe: From baseline to 3 months

Any subject that had evaluable data, yet had not undergone a conversion to arthroplasty was deemed eligible for effectiveness evaluation and included in the analysis. 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.

Outcome measures

Outcome measures
Measure	Calypso Knee System n=81 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=72 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
WOMAC Pain Percent Change to Month 3	-55.5 percentage of change Standard Deviation 29.3	-33.4 percentage of change Standard Deviation 35.8

SECONDARY outcome

Timeframe: From baseline to 24 months

Outcome measures

Outcome measures
Measure	Calypso Knee System n=72 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=58 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
WOMAC Pain Percent Change to Month 24	-76.0 percentage of change Standard Deviation 28.2	-64.7 percentage of change Standard Deviation 33.0

SECONDARY outcome

Timeframe: From baseline to 3 months

Outcome measures

Outcome measures
Measure	Calypso Knee System n=81 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=75 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
WOMAC Function Percent Change to Month 3	-52.2 percentage of change Standard Deviation 32.0	-25.2 percentage of change Standard Deviation 37.0

SECONDARY outcome

Timeframe: From baseline to 24 months

Outcome measures

Outcome measures
Measure	Calypso Knee System n=72 Participants The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=64 Participants Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
WOMAC Function Percent Change to Month 24	-73.9 percentage of change Standard Deviation 29.6	-58.8 percentage of change Standard Deviation 35.8

Adverse Events

Calypso Knee System

Serious events: 18 serious events

Other events: 20 other events

Deaths: 0 deaths

High Tibial Osteotomy (HTO)

Serious events: 39 serious events

Other events: 14 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Other adverse events
Measure	Calypso Knee System n=81 participants at risk The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=81 participants at risk Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
Musculoskeletal and connective tissue disorders Nerve injury	6.2% 5/81 • Number of events 5 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain: Pain	19.8% 16/81 • Number of events 18 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	17.3% 14/81 • Number of events 14 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).

Additional Information

Rose Weinstein, Director of Clinical Affairs

Moximed, Inc.

Phone: 415-312-0255

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee Institution agrees study is multi-center study conducted by Sponsor and agrees not to publish until study completion and not before publication of multi-center results in peer-reviewed journal. Thereafter, Institution may publish its site experience. Sponsor reserves exclusive right to publish results and establish authorship based on compliance, contribution and acceptance of responsibilities. If no publication submitted by Sponsor within 12 months of study closure, Institution may publish.
Publication restrictions are in place

Restriction type: OTHER

Measure	Calypso Knee System n=81 participants at risk The Calypso Knee System is an extra-capsular knee implant designed to fill the therapeutic gap between conservative care and more invasive surgical interventions for knee osteoarthritis.	High Tibial Osteotomy (HTO) n=81 participants at risk Historical Control: HTO is a surgical treatment intended to reduce or eliminate pain and improve the function of a knee affected by medial compartment OA. All subjects underwent an open wedge osteotomy (OWO).
Infections and infestations Infection: Cellulitis	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Infections and infestations Infection: Deep	4.9% 4/81 • Number of events 4 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	2.5% 2/81 • Number of events 2 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Infections and infestations Infection: Superficial incisional surgical site	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Anesthesia complications: Other	2.5% 2/81 • Number of events 2 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Discomfort: Catching or pulling sensations	2.5% 2/81 • Number of events 2 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Discomfort: Inability to perform certain tasks	2.5% 2/81 • Number of events 2 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Hospital readmission: Removal of implant due to dissatisfaction	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Nerve injury	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Other: Other, bone consolidation	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	3.7% 3/81 • Number of events 3 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Pain: Pain	4.9% 4/81 • Number of events 4 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	35.8% 29/81 • Number of events 30 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Scar formation: Other	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Scar formation: Periprosthetic adhesions/fibrosis	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Swelling: Swelling	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	2.5% 2/81 • Number of events 2 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Wound: Other	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Musculoskeletal and connective tissue disorders Wound: Wound dehiscence (post-explant)	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Vascular disorders Bleeding: Hematoma	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Vascular disorders Thrombophlebitis: Superficial Thrombophlebitis	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).
Psychiatric disorders Psychological event: Other	1.2% 1/81 • Number of events 1 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).	0.00% 0/81 • Index procedure (enrollment) through 24 months (790 days) Serious Adverse Events reported as adjudicated as device and/or procedure related by the Clinical Events Committee (CEC).