The Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty

A Randomized, Controlled, Prospective Study Evaluating the Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty.

Short and long term outcomes of total knee arthroplasty patients surgically exposed with patellar eversion are compared to those patients exposed by laterally retracting the patella. It was hypothesized that there would be no difference.

Study Overview

• Status: Completed
• Conditions: Arthroplasty; Total Knee Replacement; Patella
• Intervention / Treatment: Procedure: Primary Total Knee Replacement Surgery

Detailed Description

Background:

Patellar mobilization during total knee arthroplasty (TKA) has been debated, with some proponents of minimally invasive TKA suggesting that laterally retracting, rather than everting the patella may be beneficial. It was our hypothesis that by using randomized, prospective, blinded study methods, there would be no significant difference in clinical outcome measures based solely on eversion of the patella during total knee arthroplasty.

Methods:

After an a priori power analysis was done, 120 primary total knee replacements indicated for degenerative joint disease were included in the study and randomized to one of two patella exposure techniques: lateral retraction or eversion. Collaborating investigators and patients were blinded to randomization.

• Study Type: Interventional
• Enrollment (Actual): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New York
    • New York, New York, United States, 10021
      • Lenox Hill Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Patients eligible for study participation included all comers for primary total knee arthroplasty indicated for degenerative joint disease. All operations were performed by three well-established arthroplasty-fellowship-trained orthopaedic surgeons using surgical techniques based on that of a senior surgeon. All implanted devices were cruciate-substituting tricompartmental total knee replacements placed through a medial parapatellar approach. All patients were anaesthetized with spinal anesthesia, received a peri-operative cocktail injection, and had tourniquet times between 0 and 120 minutes. Multi-modal post-operative pain management and accelerated physical therapy were performed as previously described.

Exclusion Criteria:

• Patients were excluded from the study if on the operative side they had undergone prior total knee replacement, prior knee arthrotomy, prior osteotomy at or about the knee, or had preoperative angular deformity greater than 20 degrees.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Patellar Eversion; Patients randomized to the Patellar Eversion arm of the study were surgically exposed by everting the patella during their Primary Total Knee Replacement Surgery.	Procedure: Primary Total Knee Replacement Surgery; Patients randomized to the eversion group had patellas everted during the flexion portions of the surgery. Patients randomized to the retraction group had patellas everted only for the patellar resurfacing portions of the surgery. Both groups were mobilized with anterior tibial translation. All other aspects of surgery including postoperative care, anticoagulation, pain control, and physical therapy were done as per standard arthroplasty protocols at our institution.
Active Comparator: Patellar Lateral Retraction; Patients randomized to the Patellar Lateral Retraction arm of the study were surgically exposed by laterally retracting the patella during their Primary Total Knee Replacement Surgery.	Procedure: Primary Total Knee Replacement Surgery; Patients randomized to the eversion group had patellas everted during the flexion portions of the surgery. Patients randomized to the retraction group had patellas everted only for the patellar resurfacing portions of the surgery. Both groups were mobilized with anterior tibial translation. All other aspects of surgery including postoperative care, anticoagulation, pain control, and physical therapy were done as per standard arthroplasty protocols at our institution.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in quadriceps strength	Quadriceps strength was measured isometrically using a Biodex dynamometer with the patient's knee in 60 degrees of flexion.	preop, 6 weeks, 3 months, 1 year postop

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in ability to perform straight leg raise	For the purposes of this study, we defined the ability to straight leg raise as a patient independently raising their heel 6 inches off of the bed with foot dorsiflexed and knee fully extended without extension lag.	up to three days postop
change in Visual Analog Scale of Pain	Patient reported pain using standardized VAS diagram	preop, up to 3 days postop, 6 weeks, 3 months, and 1 year postop
change in Ambulation Distance		up to 3 days postop
Length of Hospital Stay		expected average 2 to 3 days
change in SF-36 score		preop, 6 weeks, 3 months, 1 year postop
change in Range of knee motion	goniometer used to standardize measurements	preop, 6 weeks, 3months, 1 year

Collaborators and Investigators

• Sponsor: Northwell Health
• Investigators: Principal Investigator: Jose A Rodriguez, MD, Lenox Hill Hospital; Study Director: Derek R Jenkins, MD, Mayo Clinic

Study record dates

Study Major Dates

• Study Start: March 1, 2009
• Primary Completion (Actual): April 1, 2012
• Study Completion (Actual): April 1, 2012

Study Registration Dates

• First Submitted: January 22, 2013
• First Submitted That Met QC Criteria: January 25, 2013
• First Posted (Estimate): January 28, 2013

Study Record Updates

• Last Update Posted (Estimate): January 28, 2013
• Last Update Submitted That Met QC Criteria: January 25, 2013
• Last Verified: January 1, 2013

More Information

Terms related to this study

• Keywords: Outcomes; SF-36; Total Knee Replacement; Patellar Eversion; Surgical Exposure; Quadriceps Strength; Straight Leg Raise
• Other Study ID Numbers: Patellar Mobilization