Trial Outcomes & Findings for Comparison of Three Surgical Techniques to Achieve Patella Symmetry During Resection (NCT NCT01822574)

Results Overview

Post-resection symmetry of the patella was independently assessed by a resident or fellow who was not involved in the resection. This was evaluated by dividing the patella into four equal quadrants and measuring the thickness in the center of each quadrant using a ring tipped or "C"-shaped caliper. The difference between the thickest and thinnest measurements of the patella was reported as the value of asymmetry.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

90 participants

Primary outcome timeframe

approximate average surgery time of 3 hours

Results posted on

2016-03-02

Participant Flow

Participants were recruited from the orthopedic department at Mayo Clinic in Rochester, Minnesota.

Participant milestones

Participant milestones
Measure	Cutting Guide Technique The guide is clamped onto the patella and tightened so that it remains stable. The guide has a slot that allows insertion of a standard sagittal saw blade, and this slot guides the blade as it is advanced across the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Haptic Feedback Technique It consists of a free hand cut (no guide used) with a standard sagittal saw that is oriented based on osteo-cartilaginous landmarks and haptic palpation of the patella by the surgeon. The resection thickness/obliquity can be altered based on haptic feedback (use of the sense of touch) of the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Four Quadrant Technique Resection is performed in a free handed fashion, but after resection, the thickness of the patella is measured separately in all four quadrants (superolateral, superomedial, inferomedial, and inferolateral). Additional resection is performed as needed based on the quadrant measurements and the measurements are repeated after each resection until satisfactory resection thickness and symmetry are obtained.
Overall Study STARTED	30	30	30
Overall Study COMPLETED	30	30	30
Overall Study NOT COMPLETED	0	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Comparison of Three Surgical Techniques to Achieve Patella Symmetry During Resection

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Cutting Guide Technique n=30 Participants The guide is clamped onto the patella and tightened so that it remains stable. The guide has a slot that allows insertion of a standard sagittal saw blade, and this slot guides the blade as it is advanced across the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Haptic Feedback Technique n=30 Participants It consists of a free hand cut (no guide used) with a standard sagittal saw that is oriented based on osteo-cartilaginous landmarks and haptic palpation of the patella by the surgeon. The resection thickness/obliquity can be altered based on haptic feedback (use of the sense of touch) of the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Four Quadrant Technique n=30 Participants Resection is performed in a free handed fashion, but after resection, the thickness of the patella is measured separately in all four quadrants (superolateral, superomedial, inferomedial, and inferolateral). Additional resection is performed as needed based on the quadrant measurements and the measurements are repeated after each resection until satisfactory resection thickness and symmetry are obtained.	Total n=90 Participants Total of all reporting groups
Age, Continuous	71.1 years n=5 Participants	64.4 years n=7 Participants	67.3 years n=5 Participants	67.6 years n=4 Participants
Sex: Female, Male Female	16 Participants n=5 Participants	14 Participants n=7 Participants	18 Participants n=5 Participants	48 Participants n=4 Participants
Sex: Female, Male Male	14 Participants n=5 Participants	16 Participants n=7 Participants	12 Participants n=5 Participants	42 Participants n=4 Participants
Region of Enrollment United States	30 participants n=5 Participants	30 participants n=7 Participants	30 participants n=5 Participants	90 participants n=4 Participants

PRIMARY outcome

Timeframe: approximate average surgery time of 3 hours

Post-resection symmetry of the patella was independently assessed by a resident or fellow who was not involved in the resection. This was evaluated by dividing the patella into four equal quadrants and measuring the thickness in the center of each quadrant using a ring tipped or "C"-shaped caliper. The difference between the thickest and thinnest measurements of the patella was reported as the value of asymmetry.

Outcome measures

Outcome measures
Measure	Cutting Guide Technique n=30 Participants The guide is clamped onto the patella and tightened so that it remains stable. The guide has a slot that allows insertion of a standard sagittal saw blade, and this slot guides the blade as it is advanced across the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Haptic Feedback Technique n=30 Participants It consists of a free hand cut (no guide used) with a standard sagittal saw that is oriented based on osteo-cartilaginous landmarks and haptic palpation of the patella by the surgeon. The resection thickness/obliquity can be altered based on haptic feedback (use of the sense of touch) of the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Four Quadrant Technique n=30 Participants Resection is performed in a free handed fashion, but after resection, the thickness of the patella is measured separately in all four quadrants (superolateral, superomedial, inferomedial, and inferolateral). Additional resection is performed as needed based on the quadrant measurements and the measurements are repeated after each resection until satisfactory resection thickness and symmetry are obtained.
Mean Asymmetry of the Patella After Patella Resection	1.73 mm Standard Deviation 1.04	1.40 mm Standard Deviation 0.88	0.85 mm Standard Deviation 0.73

SECONDARY outcome

Timeframe: Time 0 (prior to patella resection), and after surgery (approximately 3 hours)

This outcome measure attempts to capture the most accurate method for obtaining a desired thickness. Each patellar resection procedure began by exposing the articular surface of the patella. Once the patella was fully exposed and the surgeon measured the native patellar thickness, the timer was started. The surgeon then stated their goal for post resection thickness, and these values were recorded. After the final resection, the timer was stopped. The ability to obtain the resection goal was independently assessed by a resident or fellow not involved in the resection. This was calculated by taking the difference between the surgeon's goal and the average thickness of the four quadrants measured by the resident or fellow.

Outcome measures

Outcome measures
Measure	Cutting Guide Technique n=30 Participants The guide is clamped onto the patella and tightened so that it remains stable. The guide has a slot that allows insertion of a standard sagittal saw blade, and this slot guides the blade as it is advanced across the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Haptic Feedback Technique n=30 Participants It consists of a free hand cut (no guide used) with a standard sagittal saw that is oriented based on osteo-cartilaginous landmarks and haptic palpation of the patella by the surgeon. The resection thickness/obliquity can be altered based on haptic feedback (use of the sense of touch) of the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Four Quadrant Technique n=30 Participants Resection is performed in a free handed fashion, but after resection, the thickness of the patella is measured separately in all four quadrants (superolateral, superomedial, inferomedial, and inferolateral). Additional resection is performed as needed based on the quadrant measurements and the measurements are repeated after each resection until satisfactory resection thickness and symmetry are obtained.
The Difference Between Surgeon Goal and Actual Resection Height	1.40 mm Standard Deviation 1.04	0.66 mm Standard Deviation 0.64	0.66 mm Standard Deviation 0.59

SECONDARY outcome

Timeframe: Time 0 (prior to patella resection), and after surgery (approximately 3 hours)

Each patellar resection procedure began by exposing the articular surface of the patella. Once the patella was fully exposed and the surgeon measured the native patellar thickness, the timer was started. After the final resection, the timer was stopped.

Outcome measures

Outcome measures
Measure	Cutting Guide Technique n=30 Participants The guide is clamped onto the patella and tightened so that it remains stable. The guide has a slot that allows insertion of a standard sagittal saw blade, and this slot guides the blade as it is advanced across the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Haptic Feedback Technique n=30 Participants It consists of a free hand cut (no guide used) with a standard sagittal saw that is oriented based on osteo-cartilaginous landmarks and haptic palpation of the patella by the surgeon. The resection thickness/obliquity can be altered based on haptic feedback (use of the sense of touch) of the patella. The thickness is then measured in the center of the patella to ensure that the resection goal is achieved. Additional resection may be performed as needed.	Four Quadrant Technique n=30 Participants Resection is performed in a free handed fashion, but after resection, the thickness of the patella is measured separately in all four quadrants (superolateral, superomedial, inferomedial, and inferolateral). Additional resection is performed as needed based on the quadrant measurements and the measurements are repeated after each resection until satisfactory resection thickness and symmetry are obtained.
Time to Complete Patella Resurfacing	128 seconds Standard Deviation 76.8	102 seconds Standard Deviation 34.7	110 seconds Standard Deviation 62.5

Adverse Events

Cutting Guide Technique

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Haptic Feedback Technique

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Four Quadrant Technique

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Robert T. Trousdale, M.D.

Mayo Clinic

Phone: 507-284-6586

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place