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

Northwell Health120 enrolled

Overview

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.

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

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

120

Conditions

Total Knee Replacement Arthroplasty Patella

Interventions

Primary Total Knee Replacement SurgeryPROCEDURE

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.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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.

Locations (1)

Lenox Hill Hospital

New York, New York, United States

Outcomes

Primary Outcomes

change in quadriceps strength

Quadriceps strength was measured isometrically using a Biodex dynamometer with the patient's knee in 60 degrees of flexion.

Time frame: preop, 6 weeks, 3 months, 1 year postop

Secondary Outcomes

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.

Time frame: up to three days postop

change in Visual Analog Scale of Pain

Patient reported pain using standardized VAS diagram

Time frame: preop, up to 3 days postop, 6 weeks, 3 months, and 1 year postop

change in Ambulation Distance

Time frame: up to 3 days postop

Length of Hospital Stay

Time frame: expected average 2 to 3 days

change in SF-36 score

Time frame: preop, 6 weeks, 3 months, 1 year postop

change in Range of knee motion

goniometer used to standardize measurements

Time frame: preop, 6 weeks, 3months, 1 year

Data from ClinicalTrials.gov

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