An interventional study of Calypso Knee System (Implantable Shock Absorber) in Osteoarthritis, Knee, sponsored by Moximed. Completed at 5 sites in United States. Open to participants aged 25 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-07-29.
Sponsored by Moximed · Not applicable, Interventional, and Treatment
A clinical 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.
Prospective, multicenter clinical study of the Calypso Knee System. 81 subjects were enrolled in this study. Male or female subjects age 25 to 65 years, with a diagnosis of medial knee osteoarthritis and study knee pain with an overall WOMAC pain score ≥ 40 (scale 0-100).
The Calypso group was investigated under two clinical protocols, CP0001 in the USA, and CP0002 in Europe. Both clinical protocols followed the same supporting protocols and plans, such as radiographic, statistical, Clinical Events Committee (CEC), etc. The results from the combined analysis have been reported in both NCT03671213 (CP0001) and NCT03838978 (CP0002).
3,302 studies on the registry are indexed under Osteoarthritis, Knee; 608 are open to participants now.
This study's enrollment of 81 is above the median of 70 across 2,731 interventional studies indexed under Osteoarthritis, Knee.
Browse Osteoarthritis, Knee studies →Moximed is the lead sponsor of 8 studies on the registry; 2 are open to participants now.
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Exclusion Criteria:
Calypso Knee System
Device: Calypso Knee System (Implantable Shock Absorber)
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.
Also known as: MISHA® Knee System
Composite Clinical Success (CCS)
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)
Time frame: From baseline to 24 months
Time to Full Weight Bearing (Days)
Any subject that had evaluable data was deemed eligible for effectiveness evaluation and included in the analysis.
Time frame: Through study completion (Number of days to full weight bearing)
WOMAC Pain Percent Change to Month 3
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.
Time frame: From baseline to 3 months
WOMAC Pain Percent Change to Month 24
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.
Time frame: From baseline to 24 months
WOMAC Function Percent Change to Month 3
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.
Time frame: From baseline to 3 months
WOMAC Function Percent Change to Month 24
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.
Time frame: From baseline to 24 months
| Milestone | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| Started | 81 | 81 |
| Completed | 73 | 65 |
| Not completed | 8 | 16 |
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)
| percentage of subjects | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| Composite Clinical Success (CCS) | 83.5 | 57.2 |
Any subject that had evaluable data was deemed eligible for effectiveness evaluation and included in the analysis.
| days | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| Time to Full Weight Bearing (Days) | 13.4 ± 10.12 | 58 ± 39.91 |
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.
| percentage of change | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| WOMAC Pain Percent Change to Month 3 | -55.5 ± 29.3 | -33.4 ± 35.8 |
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.
| percentage of change | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| WOMAC Pain Percent Change to Month 24 | -76.0 ± 28.2 | -64.7 ± 33.0 |
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.
| percentage of change | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| WOMAC Function Percent Change to Month 3 | -52.2 ± 32.0 | -25.2 ± 37.0 |
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.
| percentage of change | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| WOMAC Function Percent Change to Month 24 | -73.9 ± 29.6 | -58.8 ± 35.8 |
Collected over Index procedure (enrollment) through 24 months (790 days). Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Calypso Knee System | 0/81 (0%) | 18/81 (22.2%) | 20/81 (24.7%) |
| High Tibial Osteotomy (HTO) | 0/81 (0%) | 39/81 (48.1%) | 14/81 (17.3%) |
| Event | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| Pain: PainMusculoskeletal and connective tissue disorders | 4/81 | 29/81 |
| Infection: DeepInfections and infestations | 4/81 | 2/81 |
| Other: Other, bone consolidationMusculoskeletal and connective tissue disorders | 0/81 | 3/81 |
| Anesthesia complications: OtherMusculoskeletal and connective tissue disorders | 2/81 | 0/81 |
| Discomfort: Catching or pulling sensationsMusculoskeletal and connective tissue disorders | 2/81 | 0/81 |
| Discomfort: Inability to perform certain tasksMusculoskeletal and connective tissue disorders | 2/81 | 0/81 |
| Swelling: SwellingMusculoskeletal and connective tissue disorders | 0/81 | 2/81 |
| Infection: CellulitisInfections and infestations | 1/81 | 0/81 |
| Infection: Superficial incisional surgical siteInfections and infestations | 0/81 | 1/81 |
| Hospital readmission: Removal of implant due to dissatisfactionMusculoskeletal and connective tissue disorders | 1/81 | 0/81 |
| Event | Calypso Knee System | High Tibial Osteotomy (HTO) |
|---|---|---|
| Pain: PainMusculoskeletal and connective tissue disorders | 16/81 | 14/81 |
| Nerve injuryMusculoskeletal and connective tissue disorders | 5/81 | 0/81 |
| Age, Continuous(years) | Calypso Knee System | High Tibial Osteotomy (HTO) | Total |
|---|---|---|---|
| Mean | 51.2 ± 7.71 | 52.5 ± 7.58 | 51.8 ± 7.65 |
| Sex: Female, Male(Participants) | Calypso Knee System | High Tibial Osteotomy (HTO) | Total |
|---|---|---|---|
| Female | 32 | 28 | 60 |
| Male | 49 | 53 | 102 |
| Ethnicity (NIH/OMB)(Participants) | Calypso Knee System | High Tibial Osteotomy (HTO) | Total |
|---|---|---|---|
| Hispanic or Latino | 3 | 1 | 4 |
| Not Hispanic or Latino | 78 | 50 | 128 |
| Unknown or Not Reported | 0 | 30 | 30 |
| Race (NIH/OMB)(Participants) | Calypso Knee System | High Tibial Osteotomy (HTO) | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 1 | 0 | 1 |
| White | 80 | 80 | 160 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 1 | 1 |
| Body Mass Index (BMI)(kg/m^2) | Calypso Knee System | High Tibial Osteotomy (HTO) | Total |
|---|---|---|---|
| Mean | 28.4 ± 3.44 | 29.3 ± 4.36 | 28.8 ± 3.94 |
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