Trial Outcomes & Findings for Total Knee Arthroplasty: Functional and Clinical Outcomes (NCT NCT01811563)

NCT ID: NCT01811563

Last Updated: 2017-06-02

Results Overview

The lower quarter y-balance test (YBT-LQ) is a test of dynamic balance in unilateral stance that has been deemed to be reliable and valid. The YBT-LQ consists of each patient standing on one leg and reaching as far as they can with their non-stance leg in the anterior, posteromedial and posterolateral direction while standing on the other foot on a centralized stance platform. The composite score is calculated as the sum of the three reach directions divided by 3 time the limb length and will be reported as a percentage of limb length.

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 60 participants
• Primary outcome timeframe: Baseline (Pre-Operative) to 6 weeks following total knee replacement
• Results posted on: 2017-06-02

Participant Flow

60 patients signed consent form but 12 were withdrawn at the time of surgery because they required a different implant not included in the study.

Participant milestones

Measure	Stryker Subjects will be receiving the Stryker Triathlon total knee replacement Stryker	Zimmer Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer
Overall Study STARTED	25	23
Overall Study COMPLETED	20	20
Overall Study NOT COMPLETED	5	3

Reasons for withdrawal

Measure	Stryker Subjects will be receiving the Stryker Triathlon total knee replacement Stryker	Zimmer Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer
Overall Study Lost to Follow-up	5	2
Overall Study Incorrect Randomization procedure	0	1

Baseline Characteristics

Total Knee Arthroplasty: Functional and Clinical Outcomes

Baseline characteristics by cohort

Measure	Stryker n=25 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker	Zimmer n=23 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Total n=48 Participants Total of all reporting groups
Age, Continuous	61.9 years STANDARD_DEVIATION 8.0 • n=5 Participants	63.1 years STANDARD_DEVIATION 7.3 • n=7 Participants	62.5 years STANDARD_DEVIATION 7.6 • n=5 Participants
Sex: Female, Male Female	14 Participants n=5 Participants	10 Participants n=7 Participants	24 Participants n=5 Participants
Sex: Female, Male Male	11 Participants n=5 Participants	13 Participants n=7 Participants	24 Participants n=5 Participants
Region of Enrollment United States	25 participants n=5 Participants	23 participants n=7 Participants	48 participants n=5 Participants

PRIMARY outcome

Timeframe: Baseline (Pre-Operative) to 6 weeks following total knee replacement

Population: Only subjects that were able to complete all of the YBT assessments at 6 weeks post total knee replacement were included in the analyses.

The lower quarter y-balance test (YBT-LQ) is a test of dynamic balance in unilateral stance that has been deemed to be reliable and valid. The YBT-LQ consists of each patient standing on one leg and reaching as far as they can with their non-stance leg in the anterior, posteromedial and posterolateral direction while standing on the other foot on a centralized stance platform. The composite score is calculated as the sum of the three reach directions divided by 3 time the limb length and will be reported as a percentage of limb length.

Outcome measures

Measure	Zimmer n=22 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=21 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in Lower Quarter Y-Balance Test (YBT-LQ) (Dynamic Balance) From Baseline to 6 Weeks Following Total Knee Replacement YBT-LQ Composite 6 weeks	73.32 % of limb length Standard Deviation 9.15	73.25 % of limb length Standard Deviation 7.95
Change in Lower Quarter Y-Balance Test (YBT-LQ) (Dynamic Balance) From Baseline to 6 Weeks Following Total Knee Replacement YBT-LQ Composite Pre-Operative	67.52 % of limb length Standard Deviation 12.22	69.98 % of limb length Standard Deviation 8.18

PRIMARY outcome

Timeframe: Baseline (Pre-Operative) to 52 weeks following total knee replacement

Population: Subjects used in the final analysis were those subjects who completed the assessment at pre-op and 1 year post-op (20 subjects per arm).

The lower quarter y-balance test (YBT-LQ) is a test of dynamic balance in unilateral stance that has been deemed to be reliable and valid. The YBT-LQ consists of each patient standing on one leg and reaching as far as they can with their non-stance leg in the anterior, posteromedial and posterolateral direction while standing on the other foot on a centralized stance platform. The composite score is calculated as the sum of the three reach directions divided by 3 time the limb length and will be reported as a percentage of limb length.

Outcome measures

Measure	Zimmer n=20 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=20 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in Lower Quarter Y-Balance Test (YBT-LQ) (Dynamic Balance) From Baseline to 52 Weeks Following Total Knee Replacement YBT-LQ Composite Pre-Operative	79.24 % of limb length Standard Deviation 7.89	79.45 % of limb length Standard Deviation 10.46
Change in Lower Quarter Y-Balance Test (YBT-LQ) (Dynamic Balance) From Baseline to 52 Weeks Following Total Knee Replacement YBT-LQ Composite Post-Op 52 Weeks	69.42 % of limb length Standard Deviation 13.39	70.44 % of limb length Standard Deviation 9.31

SECONDARY outcome

Timeframe: Baseline and 52 weeks following total knee replacement

Each subject will complete three walking trials at a self-selected comfortable walking speed along a 5 meter walkway in order to record walking speed at each time point.

Outcome measures

Measure	Zimmer n=20 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=20 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in Walking Speed From Baseline to 52 Weeks Following Total Knee Replacement. Walking Speed Post-Op 52 Weeks	1.28 miles per hour Standard Deviation 0.23	1.41 miles per hour Standard Deviation 0.23
Change in Walking Speed From Baseline to 52 Weeks Following Total Knee Replacement. Walking Speed Pre-Operative	1.16 miles per hour Standard Deviation 0.28	1.22 miles per hour Standard Deviation 0.21

SECONDARY outcome

Timeframe: 6 weeks following total knee replacement

Each subject will complete three walking trials at a self-selected comfortable walking speed along a 5 meter walkway in order to record walking speed at each time point.

Outcome measures

Measure	Zimmer n=23 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=25 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Walking Speed at 6 Weeks Following Total Knee Replacement.	1.19 miles per hour Standard Deviation 0.22	1.21 miles per hour Standard Deviation 0.28

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline and 52 weeks following total knee replacement

Population: Subjects used in the final analysis were those subjects who completed the assessment at pre-op and 1 year post-op (20 subjects per arm).

The UCLA activity score is a validated patient reported outcome of overall physical activity. Results on a scale of 1 to 10, 1 is "Wholly Inactive, dependent on others, and can not leave residence" and 10 is "Regularly participates in impact sports".

Outcome measures

Measure	Zimmer n=20 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=20 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in University of California, Los Angeles (UCLA) Activity Score From Baseline to 52 Weeks Following Total Knee Replacement. UCLA Activity Pre-Operative	3.83 units on a scale Standard Deviation 1.38	4.19 units on a scale Standard Deviation 1.33
Change in University of California, Los Angeles (UCLA) Activity Score From Baseline to 52 Weeks Following Total Knee Replacement. UCLA Activity Post-Op 52 Weeks	5.61 units on a scale Standard Deviation 1.91	5.90 units on a scale Standard Deviation 1.55

OTHER_PRE_SPECIFIED outcome

Timeframe: 6 weeks following total knee replacement

Population: Only subjects who were able to complete the UCLA at six weeks were included in the analysis.

The UCLA activity score is a validated patient reported outcome of overall physical activity. Results on a scale of 1 to 10, 1 is "Wholly Inactive, dependent on others, and can not leave residence" and 10 is "Regularly participates in impact sports".

Outcome measures

Measure	Zimmer n=22 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=25 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
University of California, Los Angeles (UCLA) Activity Score at 6 Weeks Following Total Knee Replacement.	4.73 units on a scale Standard Deviation 1.52	4.48 units on a scale Standard Deviation 1.42

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline (Pre-Operative) and 52 weeks following total knee replacement

Population: Subjects used in the final analysis were those subjects who completed the assessment at pre-op and 1 year post-op (20 subjects per arm).

The KOOS is a standardized and validated patient outcome score that assesses functional limitation in patient with knee problems. KOOS consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). The previous week is the time period considered when answering the questions. Standardized answer options are given (5 Likert boxes) and each question is assigned a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale.

Outcome measures

Measure	Zimmer n=20 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=20 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in Knee Injury and Osteoarthritis Outcome Score (KOOS) Total From Baseline to 52 Weeks Following Total Knee Replacement. KOOS Total, Post-Op 52 week	64.24 units on a scale Standard Deviation 38.79	67.32 units on a scale Standard Deviation 35.62
Change in Knee Injury and Osteoarthritis Outcome Score (KOOS) Total From Baseline to 52 Weeks Following Total Knee Replacement. KOOS Total, Baseline Pre-Operative	46.08 units on a scale Standard Deviation 13.50	45.60 units on a scale Standard Deviation 12.32

OTHER_PRE_SPECIFIED outcome

Timeframe: 6 weeks and 52 weeks following total knee replacement

Population: Participants who completed the Forgotten Joint Score (FJS) at week 6 and week 52. Not all subjects completed the FJS.

The FJS is a patient reported measure of how bothersome the total joint replacement is for them, how much it affects daily activity and how much they are aware of the implant. The FJS is a 12-question survey regarding functional outcome, pain, stability, daily living, activity and sport. Scoring is from 0 to 4 with 0 as the best outcome; a low score means high satisfaction. Not all questions must be answered to score, all responses are summed and the total is divided by number of completed items multiplied by 25, with the final result subtracted from 100. The score range is from 0 to 100 with the highest score of 100 indicating the best outcome (the joint is completely "forgotten") and 0 indicating the worst outcome.

Outcome measures

Measure	Zimmer n=20 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=20 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Change in Forgotten Joint Score (FJS) From 6 Weeks to 52 Weeks Following Total Knee Replacement. FJS, at 6 weeks	76.59 units on a scale Standard Deviation 20.39	69.63 units on a scale Standard Deviation 20.9
Change in Forgotten Joint Score (FJS) From 6 Weeks to 52 Weeks Following Total Knee Replacement. FJS, at 52 weeks	30.8 units on a scale Standard Deviation 29.6	37.7 units on a scale Standard Deviation 21.4

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline (Pre-Operative), 6 weeks and 52 weeks following total knee replacement

Population: Only 20 subjects in each arm completed the assessment at 1 year post-op.

The KSS is a patient reported measure of knee function that is specific to patients who are scheduled to receive or have previously had a total knee replacement. This outcome measures both patient reported pain and function changes from prior to surgery through recovery. The score range is from 0 to 100. The highest score of 100 points will be obtained by a well-aligned knee with no pain, 125 degrees of motion, and negligible anteroposterior and mediolateral instability.

Outcome measures

Measure	Zimmer n=23 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=25 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Knee Society Score (KSS) KSS Functional Activity, 52 weeks Post-operative	64.2 units on a scale Standard Deviation 38.8	67.3 units on a scale Standard Deviation 35.6
Knee Society Score (KSS) KSS Satisfaction, Baseline Pre-Operatively	13.6 units on a scale Standard Deviation 8.8	11.1 units on a scale Standard Deviation 5.2
Knee Society Score (KSS) KSS Satsifaction, 6 weeks	29.5 units on a scale Standard Deviation 8.8	28.9 units on a scale Standard Deviation 7.3
Knee Society Score (KSS) KSS Functional Activity, Baseline	47.0 units on a scale Standard Deviation 13.7	44.3 units on a scale Standard Deviation 11.2
Knee Society Score (KSS) KSS Functional Activity, 6 weeks	61.6 units on a scale Standard Deviation 16.7	60.8 units on a scale Standard Deviation 18.1

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline (Pre-Operative), 6 weeks and 52 weeks following total knee replacement

Population: The 6 week time point was not used in the final analysis based on the clinical decision that 6 weeks was too early in recovery to provide accurate information for clinical decision making. Subjects used in the final analysis were those subjects who completed the assessment at pre-op and 1 year post-op (20 subjects per arm).

The sit to stand test requires patients to stand up and sit down as many times as possible in 10 seconds from a standard arm chair.

Outcome measures

Measure	Zimmer n=23 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=25 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Sit to Stand Time Sit to stand Pre-Operative	4.34 Number of times Standard Deviation 1.34	3.90 Number of times Standard Deviation 0.95
Sit to Stand Time Sit to stand Post-Op 6 weeks	4.6 Number of times Standard Deviation 1.1	4.5 Number of times Standard Deviation 1.7
Sit to Stand Time Sit to stand Post-Op 52 weeks	5.47 Number of times Standard Deviation 1.81	5.40 Number of times Standard Deviation 1.45

OTHER_PRE_SPECIFIED outcome

Timeframe: Baseline (Pre-Operative), 6 weeks and 52 weeks following total knee replacement

Population: The 6 week time point was not used in the final analysis based on the clinical decision that 6 weeks was too early in recovery to provide accurate information for clinical decision making. Subjects used in the final analysis were those subjects who completed the assessment at pre-op and 1 year post-op (20 subjects per arm).

The timed up and go requires a patient to rise from a chair walk three meters around a piece of tape and return to the chair again as quickly as possible.

Outcome measures

Measure	Zimmer n=23 Participants Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer	Stryker n=24 Participants Subjects will be receiving the Stryker Triathlon total knee replacement Stryker
Timed Get up and go Timed up and go Pre-Operative	9.07 Seconds Standard Deviation 2.48	9.55 Seconds Standard Deviation 3.86
Timed Get up and go Timed up and go Post-Op 6 weeks	8.89 Seconds Standard Deviation 1.89	9.38 Seconds Standard Deviation 3.58
Timed Get up and go Timed up and go Post-Op 52 weeks	7.17 Seconds Standard Deviation 1.39	6.99 Seconds Standard Deviation 1.8

Adverse Events

Stryker

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

Zimmer

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Stryker n=25 participants at risk Subjects will be receiving the Stryker Triathlon total knee replacement Stryker	Zimmer n=23 participants at risk Subjects will be receiving a Zimmer NexGen total knee replacement Zimmer
Musculoskeletal and connective tissue disorders Patient fell while completeing the 6 weeks testing	4.0% 1/25 • Number of events 1 • 52 weeks	0.00% 0/23 • 52 weeks

Additional Information

Samuel Wellman, MD

Duke University Medical Center

Phone: 919-681-4055

Email: samuel.wellman@duke.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place