CPI: Knee Arthroplasty Performed With Conventional and Customized Instrumentation

• Sponsor: Anderson Orthopaedic Research Institute (Other)
• Overall Status: Completed
• CT.gov ID: NCT01124305
• Collaborator: (none)
• Enrollment: 70
• Location: 1
• Arms: 2
• Duration (Months): 30.1
• Patients Per Site Per Month: 2.3

Study Details

Study Description

Brief Summary

The main purpose of this study is to determine whether the surgical time required for primary total knee arthroplasty is significantly less when performed with Customized Patient Instrumentation (CPI) than with conventional instrumentation. Each case will be recorded by video camera, in order to time the length of surgery and each surgical step. The number of surgical trays required for each case will be recorded. As an additional endpoint, the investigators will measure limb and component alignment on x-rays to determine if these two methods achieve equivalent alignment results. The thickness of bone cuts will be compared to the surgical plan and to each other.

The primary hypothesis is that the use of customized patient instrumentation will reduce the operative time required for total knee arthroplasty.

Condition or Disease	Intervention/Treatment	Phase
Knee Arthritis	Device: Customized Patient Instrumentation; Device: Traditional Instrumentation	Phase 4

Detailed Description

Patient-specific instrumentation (PSI) has been developed for total knee arthroplasty (TKA) with several potential advantages over traditional instrumentation (TI). Shortened surgical time, fewer surgical instruments, and improved alignment are some of these proposed advantages. We sought to examine these assertions.

52 patients (26 per group) were enrolled in a prospective, randomized trial comparing CT-based PSI with TI. No difference was seen in average patient age (68 years) or BMI (31) between groups (p=0.84 and p=0.89), although there were more males in the PSI group (14 vs 7, p=0.002). A single surgeon and consistent staff performed the surgeries with the same knee prostheses, and all cases were videotaped to measure the length of surgery and each individual step. Any additional bone cuts, size changes, or ligament releases made to achieve correct alignment and balance were documented. The number of instrument trays opened for each case was recorded. Postoperative long alignment and lateral radiographs were taken to measure the coronal and sagittal plane component alignment and mechanical axis in each patient.

Study Design

• Study Type: Interventional
• Actual Enrollment: 70 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: A Prospective, Randomized Evaluation of Total Knee Arthroplasty Performed With Conventional and Customized Patient Instrumentation
• Study Start Date: May 1, 2010
• Actual Primary Completion Date: Jul 1, 2012
• Actual Study Completion Date: Nov 1, 2012

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Traditional Instrumentation Control group: Cases performed with traditional surgical instruments	Device: Traditional Instrumentation; Traditional surgical instruments will be used to make bone cuts and size the components in this control group.
Experimental: Customized Patient Instrumentation Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.	Device: Customized Patient Instrumentation; Custom cutting guides based on computed tomography (CT) images of the patient's leg are used to make the bone cuts and select the implant size.

Outcome Measures

Primary Outcome Measures

1. Length of Surgery [1 day]

   Time elapsed from skin incision to wound closure (in seconds)

Secondary Outcome Measures

1. Length of Each Surgical Step (in Seconds) [1 day]

   surgical exposure, tibial alignment and resection, femoral distal cut, extension gap balancing, sizing the femur, 4 finishing femoral cuts, posterior releases, patellar resection, trial components, tibial tray preparation, cleanup/ prep for cement, cementing femur, cementing tibia, cementing patella, and closure

2. Number of Instrument Trays Required [1 day]

3. Limb Alignment (Mechanical Axis) [4 months]

   Alignment is measured on 4 month postoperative radiograph in degrees. The goal is a mechanical axis between and femur and tibia of 0 degrees. Varus alignment ("bow-legged") is shown as a negative number in degrees away from 0. Valgus alignment ("Knock-kneed") is expressed as a positive number in degrees away from 0.

Eligibility Criteria

Criteria

• Ages Eligible for Study: N/A and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• Patient requires unilateral primary total knee arthroplasty

Exclusion Criteria:

• Body mass index greater than 41

• Previous ipsilateral hip or ankle replacement

• Knee flexion contracture greater than 20 degrees

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Anderson Orthopaedic Research Institute	Alexandria	Virginia	United States	22306

Sponsors and Collaborators

• Anderson Orthopaedic Research Institute

Investigators

• Principal Investigator: William G Hamilton, MD, Anderson Orthopaedic Research Institute

Study Documents (Full-Text)

None provided.

More Information

Publications

• Bali K, Walker P, Bruce W. Custom-fit total knee arthroplasty: our initial experience in 32 knees. J Arthroplasty. 2012 Jun;27(6):1149-54. doi: 10.1016/j.arth.2011.12.006. Epub 2012 Jan 27.
• Howell SM, Kuznik K, Hull ML, Siston RA. Results of an initial experience with custom-fit positioning total knee arthroplasty in a series of 48 patients. Orthopedics. 2008 Sep;31(9):857-63.
• Lombardi AV Jr, Berend KR, Adams JB. Patient-specific approach in total knee arthroplasty. Orthopedics. 2008 Sep;31(9):927-30.
• Ng VY, DeClaire JH, Berend KR, Gulick BC, Lombardi AV Jr. Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA. Clin Orthop Relat Res. 2012 Jan;470(1):99-107. doi: 10.1007/s11999-011-1996-6.
• Watters TS, Mather RC 3rd, Browne JA, Berend KR, Lombardi AV Jr, Bolognesi MP. Analysis of procedure-related costs and proposed benefits of using patient-specific approach in total knee arthroplasty. J Surg Orthop Adv. 2011 Summer;20(2):112-6.

• Responsible Party: Nancy Parks, Knee Project Director, Anderson Orthopaedic Research Institute
• ClinicalTrials.gov Identifier: NCT01124305
• Other Study ID Numbers: AORI2010-0101
• First Posted: May 17, 2010
• Last Update Posted: Dec 18, 2013
• Last Verified: Nov 1, 2013

• Keywords provided by Nancy Parks, Knee Project Director, Anderson Orthopaedic Research Institute: Total Knee Arthroplasty; Instrumentation
• Additional relevant MeSH terms: Arthritis

Study Results

Participant Flow

Recruitment Details	Patients were recruited at a suburban orthopaedic clinic setting between June 2010 and Sept 2011.
Pre-assignment Detail	Patients were excluded if their medical insurance did not cover a leg CT scan or if there was any metal in their leg.

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
Period Title: Overall Study
STARTED	34	36
COMPLETED	26	26
NOT COMPLETED	8	10

Baseline Characteristics

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation	Total
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.	Total of all reporting groups
Overall Participants	34	36	70
Age (Count of Participants)
<=18 years	0 0%	0 0%	0 0%
Between 18 and 65 years	11 32.4%	11 30.6%	22 31.4%
>=65 years	23 67.6%	25 69.4%	48 68.6%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	71.3 (12.1)	69.2 (8.5)	70.1 (10.0)
Sex: Female, Male (Count of Participants)
Female	23 67.6%	19 52.8%	42 60%
Male	11 32.4%	17 47.2%	28 40%
Region of Enrollment (participants) [Number]
United States	34 100%	36 100%	70 100%

Outcome Measures

1. Primary Outcome

Title	Length of Surgery
Description	Time elapsed from skin incision to wound closure (in seconds)
Time Frame	1 day

Outcome Measure Data

Analysis Population Description

per protocol

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
Measure Participants	26	26
Mean (Standard Deviation) [seconds]	3447.19 (297.68)	3707.19 (348.26)

2. Secondary Outcome

Title	Length of Each Surgical Step (in Seconds)
Description	surgical exposure, tibial alignment and resection, femoral distal cut, extension gap balancing, sizing the femur, 4 finishing femoral cuts, posterior releases, patellar resection, trial components, tibial tray preparation, cleanup/ prep for cement, cementing femur, cementing tibia, cementing patella, and closure
Time Frame	1 day

Outcome Measure Data

Analysis Population Description

per protocol

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
Measure Participants	26	26
Exposure	297.19 (54.87)	318.38 (64.00)
Tibial Alignment and Resection	111.77 (37.67)	129.73 (29.47)
Femoral Distal Cut	95.19 (19.5)	170.46 (86.91)
Extension Gap Balancing	89.77 (73.88)	77.88 (59.35)
Sizing the Femur	41.58 (11.70)	21.46 (42.01)
4 Finishing Femoral Cuts	135.54 (35.67)	186.96 (89.69)
Posterior Releases	225.42 (46.91)	223.81 (51.68)
Patellar Resection	133.04 (27.51)	136.31 (30.41)
Trial Components	247.92 (64.76)	253.42 (78.78)
Tibial Tray Preparation	71.85 (24.20)	67.54 (24.38)
Cleanup/ Prepare for Cement	206.46 (59.32)	196.00 (53.16)
Cementing Femur	127.15 (22.86)	141.65 (22.55)
Cementing Tibia	77.77 (16.99)	83.62 (18.47)
Cementing Patella	102.65 (45.14)	97.77 (22.98)
Closure	1221.62 (140.27)	1246.69 (133.82)

3. Secondary Outcome

Title	Number of Instrument Trays Required
Time Frame	1 day

Outcome Measure Data

Analysis Population Description

per protocol

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
Measure Participants	26	26
Mean (Standard Deviation) [number of trays]	7.3 (0.69)	2.5 (1.14)

4. Secondary Outcome

Title	Limb Alignment (Mechanical Axis)
Description	Alignment is measured on 4 month postoperative radiograph in degrees. The goal is a mechanical axis between and femur and tibia of 0 degrees. Varus alignment ("bow-legged") is shown as a negative number in degrees away from 0. Valgus alignment ("Knock-kneed") is expressed as a positive number in degrees away from 0.
Time Frame	4 months

Outcome Measure Data

Analysis Population Description

All participants were x-rayed postoperatively to measure the mechanical axis of the leg in degrees.

Arm/Group Title	Traditional Instrumentation	Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments	Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
Measure Participants	26	26
Mean (Full Range) [degrees varus(-) or valgus(+)]	0.7	0.3

Adverse Events

Time Frame	4 months
Adverse Event Reporting Description	This is a study of surgical instruments, therefore the focus would be on adverse events occurring during surgery. All patients were followed for 4 months, so we also able to capture adverse events in the short-term postoperative period.
Arm/Group Title	Traditional Instrumentation		Customized Patient Instrumentation
Arm/Group Description	Control group: Cases performed with traditional surgical instruments		Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans.
All Cause Mortality
	Traditional Instrumentation		Customized Patient Instrumentation
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Traditional Instrumentation		Customized Patient Instrumentation
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/26 (0%)		0/26 (0%)
Other (Not Including Serious) Adverse Events
	Traditional Instrumentation		Customized Patient Instrumentation
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	1/26 (3.8%)		0/26 (0%)
Musculoskeletal and connective tissue disorders
Knee stiff	1/26 (3.8%)	1	0/26 (0%)	0

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.