In Vivo Determination of 3D Patellofemoral Mechanics

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT01290627

Acronym

Patella

Enrollment

Registered

2011-02-07

Start date

2011-02-28

Completion date

2011-09-30

Last updated

2019-10-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Arthroplasty Replacement Knee, Knee Prosthesis

Brief summary

This study will analyze the tibio-femoral and patellofemoral (motion) and mechanics (forces) of participants having a normal knee or a total knee arthroplasty (TKA) using one or two different (TKA) devices Low Contract Stress (LCS) Posterior Stabilizing (PS) Rotating Platform (RP) Total Knee Arthroplasty (TKA). All knees will be analyzed using an image matching technique that will convert a two-dimensional (2D) fluoroscopic image into a three-dimensional (3D) image. In conjunction with the fluoroscopic analysis, electromyography (EMG) data, and ground reaction force (GRF) data will all be allow for a complete analysis of the knee joints. These results will help the orthopaedic community better understand knee motion so they can improve testing on existing implants and develop future implants that will further enhance patients' lives.

Interventions

DEVICESubjects implanted with DePuy LCS PS RP TKA

Subjects implanted with DePuy Low Contact Stress (LCS) Poster Stabilizing (PS) Rotating Platform (RP) Total Knee Arthroplasty (TKA)

DEVICESubjects implanted with DePuy Sigma PS RP TKA

Subjects implanted with a DePuy Sigma Posterior Stabilizing (PS) Rotating Platform (RP) Total Knee Arthroplasty (TKA)

Study design

Observational model

CASE_ONLY

Time perspective

RETROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

20 Years to 85 Years

Healthy volunteers

Yes

Inclusion criteria

1. Patients must be at least six months post-operative. 2. Potential subjects will have a body weight of less than 250 lbs. 3. Candidates must have an AKS score \>70 post-operatively. 4. Patients must have passive flexion of at least 100. 5. Implanted group must have either an LCS PS RP TKA, having an anatomical patella, or Sigma PS RP TKA; or normal knee group must have normal knee. 6. Must be willing to sign both Informed Consent and HIPAA forms.

Exclusion criteria

1. Pregnant females. 2. Subjects not meeting study requirements.

Design outcomes

Primary

Measure	Time frame	Description
Patella Flexion With Respect to Femur	Average post-operative time for LCS-PS group was 56 months. Average post-operative time for PS RP group was 55.7 months.	Full extension to maximum flexion. Degrees of flexion analyzed for participants with and without implants.
Patella Rotation With Respect to Femur	Average post-operative time for LCS-PS group was 56 months. Average post-operative time for PS RP group was 55.7 months.	Patellar rotation from full extension to maximum flexion for subjects with and without implants. A positive measurement of patellar rotation refers to positive flexion of the patella about the medial-lateral axis, where the patella component rotates so that the top of the patella rotates toward the femur and the bottom rotates away. Conversely, a negative measurement refers to negative flexion of the patella about this axis, where the patellar component rotates so that the top of the patella moves away from the femur and the bottom moves towards.
Patella Tilt With Respect to Femur	Average post-operative time for LCS-PS group was 56 months. Average post-operative time for PS RP group was 55.7 months.	full extension to maximum flexion for participants with and without implants.
Normalized Medial Patella Contact Point Translation	Average post-operative time for LCS-PS group was 56 months. Average post-operative time for PS RP group was 55.7 months.	full extension to maximum flexion for participants with and without implants. Position of the patellar contact point was determined by locating the closest point to the femur on the patella throughout flexion. There are 2 patello-femoral contact points: a point on the medial aspect of the patella and a point on the lateral aspect of the patella. Throughout flexion, the medial contact point generally moves closer to the top of the patella (hence the positive value for the results). The translation of this contact point is normalized to report a ratio between -1 and 1. In other words, the distance the point has traveled compared to the total height of the patella. For example, if the patella is 8 cm in height and the point travels approximately 2 cm upwards during flexion, the value would be reported as +2/8 = +0.25. Definition of normalized: multiply (a series, function, or item of data) by a factor that makes the norm or some associated quantity such as an integral equal
Normalized Lateral Patella Contact Point Translation	Average post-operative time for LCS-PS group was 56 months. Average post-operative time for PS RP group was 55.7 months.	full extension to maximum flexion for participants with and without implants. Position of patellar contact point was determined by locating closest point to femur on patella throughout flexion. There are 2 patello-femoral contact points: 1 point on the medial aspect of the patella and 1 point on the lateral aspect of the patella. Throughout flexion, lateral contact point generally moves closer to the top of the patella (hence, the positive value for the results). The translation of this contact point is normalized to report a ratio between -1 and 1. The distance the point has traveled compared to the total height of the patella. For example, if the patella is 8 cm in height and the point travels approximately 2 cm upwards during flexion, the value would be reported as +2/8 = +0.25. Definition of normalized: multiply (a series, function, or item of data) by a factor that makes the norm or some associated quantity such as an integral equal to a desired value (usually 1).

Countries

United States

Participant flow

Recruitment details

Patients were recruited from the Colorado Joint Replacement practice of Drs. Doug Dennis and Brian Haas in Denver, CO after the study was approved by respective IRBs beginning 5/27/11.

Participants by arm

Arm	Count
Knee Prosthesis LCS PS RP TKA Subjects implanted with DePuy Low Contact Stress (LCS) Poster Stabilizing (PS) Rotating Platform (RP) Total Knee Arthroplasty (TKA)	10
Knee Prosthesis Sigma PS RP TKA Subjects implanted with a DePuy Sigma Posterior Stabilizing (PS) Rotating Platform (RP) Total Knee Arthroplasty (TKA)	10
Control Subjects with normal knees	10
Total	30

Baseline characteristics

Characteristic	Knee Prosthesis Sigma PS RP TKA	Control	Knee Prosthesis LCS PS RP TKA	Total
Age, Categorical <=18 years	0 Participants	0 Participants	0 Participants	0 Participants
Age, Categorical >=65 years	5 Participants	0 Participants	5 Participants	10 Participants
Age, Categorical Between 18 and 65 years	5 Participants	10 Participants	5 Participants	20 Participants
Age, Continuous	64.3 years STANDARD_DEVIATION 8.7	34.2 years STANDARD_DEVIATION 8.9	62.5 years STANDARD_DEVIATION 7.8	53.67 years STANDARD_DEVIATION 16.18
Region of Enrollment United States	10 participants	10 participants	10 participants	30 participants
Sex: Female, Male Female	1 Participants	8 Participants	4 Participants	13 Participants
Sex: Female, Male Male	9 Participants	2 Participants	6 Participants	17 Participants

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk	EG002 affected / at risk
deaths Total, all-cause mortality	— / —	— / —	— / —
other Total, other adverse events	0 / 10	0 / 10	0 / 10
serious Total, serious adverse events	0 / 10	0 / 10	0 / 10

Outcome results

Primary

Normalized Lateral Patella Contact Point Translation

full extension to maximum flexion for participants with and without implants. Position of patellar contact point was determined by locating closest point to femur on patella throughout flexion. There are 2 patello-femoral contact points: 1 point on the medial aspect of the patella and 1 point on the lateral aspect of the patella. Throughout flexion, lateral contact point generally moves closer to the top of the patella (hence, the positive value for the results). The translation of this contact point is normalized to report a ratio between -1 and 1. The distance the point has traveled compared to the total height of the patella. For example, if the patella is 8 cm in height and the point travels approximately 2 cm upwards during flexion, the value would be reported as +2/8 = +0.25. Definition of normalized: multiply (a series, function, or item of data) by a factor that makes the norm or some associated quantity such as an integral equal to a desired value (usually 1).