Knee Arthroplasty Performed With Conventional and Customized Instrumentation (CPI)

A Prospective, Randomized Evaluation of Total Knee Arthroplasty Performed With Conventional and Customized Patient Instrumentation

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.

Study Overview

• Status: Completed
• Conditions: Knee Arthritis
• Intervention / Treatment: Device: Traditional Instrumentation; Device: Customized Patient Instrumentation

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 Type: Interventional
• Enrollment (Actual): 70
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Virginia
    • Alexandria, Virginia, United States, 22306
      • Anderson Orthopaedic Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / 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.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	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
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

Collaborators and Investigators

• Sponsor: Anderson Orthopaedic Research Institute

Publications and helpful links

General Publications

• 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.
• 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.
• 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.
• 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.
• 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.

Study record dates

Study Major Dates

• Study Start: May 1, 2010
• Primary Completion (Actual): July 1, 2012
• Study Completion (Actual): November 1, 2012

Study Registration Dates

• First Submitted: May 12, 2010
• First Submitted That Met QC Criteria: May 13, 2010
• First Posted (Estimate): May 17, 2010

Study Record Updates

• Last Update Posted (Estimate): December 18, 2013
• Last Update Submitted That Met QC Criteria: November 25, 2013
• Last Verified: November 1, 2013

More Information

Terms related to this study

• Keywords: Total Knee Arthroplasty; Instrumentation
• Additional Relevant MeSH Terms: Joint Diseases; Musculoskeletal Diseases; Arthritis
• Other Study ID Numbers: AORI2010-0101