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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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Traditional Instrumentation | Active Comparator | Control group: Cases performed with traditional surgical instruments |
|
| Customized Patient Instrumentation | Experimental | Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Customized Patient Instrumentation | Device | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| Length of Surgery | Time elapsed from skin incision to wound closure (in seconds) | 1 day |
| Measure | Description | Time Frame |
|---|---|---|
| Length of Each Surgical Step (in Seconds) | 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 | 1 day |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| William G Hamilton, MD | Anderson Orthopaedic Research Institute | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Anderson Orthopaedic Research Institute | Alexandria | Virginia | 22306 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 18814618 | Background | Lombardi AV Jr, Berend KR, Adams JB. Patient-specific approach in total knee arthroplasty. Orthopedics. 2008 Sep;31(9):927-30. doi: 10.3928/01477447-20080901-21. No abstract available. | |
| 21809150 | Background | 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. |
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Patients were excluded if their medical insurance did not cover a leg CT scan or if there was any metal in their leg.
Patients were recruited at a suburban orthopaedic clinic setting between June 2010 and Sept 2011.
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| ID | Title | Description |
|---|---|---|
| FG000 | Traditional Instrumentation | Control group: Cases performed with traditional surgical instruments |
| FG001 | Customized Patient Instrumentation | Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans. |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Traditional Instrumentation | Control group: Cases performed with traditional surgical instruments |
| BG001 | Customized Patient Instrumentation | Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans. |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Length of Surgery | Time elapsed from skin incision to wound closure (in seconds) | per protocol | Posted | Mean | Standard Deviation | seconds | 1 day |
|
4 months
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.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Traditional Instrumentation | Control group: Cases performed with traditional surgical instruments |
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| Term | Organ System | Source Vocabulary | Assessment Type | Notes | Statistical Information |
|---|---|---|---|---|---|
| Knee stiff | Musculoskeletal and connective tissue disorders | SNOMED CT | Systematic Assessment | Manipulation under anesthesia for limited range of motion |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Knee Project Director | AORI | 7036194423 | nparks@aori.org |
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| Traditional Instrumentation | Device | Traditional surgical instruments will be used to make bone cuts and size the components in this control group. |
|
| Number of Instrument Trays Required | 1 day |
| Limb Alignment (Mechanical Axis) | 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. | 4 months |
| 18814593 | Background | 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. doi: 10.3928/01477447-20080901-15. |
| 22285230 | Background | 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. |
| 21838072 | Background | 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. |
| BG002 | Total | Total of all reporting groups |
| Participants |
|
| Age, Continuous | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Region of Enrollment | Number | participants |
|
| Units | Counts |
|---|
| Participants |
|
|
| Secondary | Length of Each Surgical Step (in Seconds) | 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 | per protocol | Posted | Mean | Standard Deviation | seconds | 1 day |
|
|
|
| Secondary | Number of Instrument Trays Required | per protocol | Posted | Mean | Standard Deviation | number of trays | 1 day |
|
|
|
| Secondary | Limb Alignment (Mechanical Axis) | 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. | All participants were x-rayed postoperatively to measure the mechanical axis of the leg in degrees. | Posted | Mean | Full Range | degrees varus(-) or valgus(+) | 4 months |
|
|
|
| 0 |
| 26 |
| 1 |
| 26 |
| EG001 | Customized Patient Instrumentation | Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans. | 0 | 26 | 0 | 26 |
|
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| Femoral Distal Cut |
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| Extension Gap Balancing |
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| Sizing the Femur |
|
| 4 Finishing Femoral Cuts |
|
| Posterior Releases |
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| Patellar Resection |
|
| Trial Components |
|
| Tibial Tray Preparation |
|
| Cleanup/ Prepare for Cement |
|
| Cementing Femur |
|
| Cementing Tibia |
|
| Cementing Patella |
|
| Closure |
|