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Vol:5 Issue:8 Number:54 ISSN#:2564-2537
Author Verified
ACE Report #9110

No significant mid-term differences between TKA with & without patella resurfacing

How to Cite

OrthoEvidence. No significant mid-term differences between TKA with & without patella resurfacing. ACE Report. 2016;5(8):54. Available from:

Study Type:Therapy
OE Level Evidence:2
Journal Level of Evidence:N/A

Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing

Acta Orthop. 2016 Jun;87(3):274-9

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74 patients scheduled for total knee arthroplasty were randomized to undergo the procedure with or without patellar resurfacing. The purpose of this study was to compare short-term functional performance measures, and mid-term patient reported outcome measures of pain, satisfaction, and disease-related quality of life between groups. No significant differences between groups in any short- or mid-term outcome were observed.

Publication Funding Details +
Not Reported
None disclosed

Risk of Bias


Reporting Criteria


Fragility Index


Was the allocation sequence adequately generated?

Was allocation adequately concealed?

Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?

Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?

Blinding Patients: Was knowledge of the allocated interventions adequately prevented?

Was loss to follow-up (missing outcome data) infrequent?

Are reports of the study free of suggestion of selective outcome reporting?

Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?

Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?

Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?

Yes = 1

Uncertain = 0.5

Not Relevant = 0

No = 0

The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.




Outcome Measurements


Inclusion / Exclusion


Therapy Description



Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65

The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.

Why was this study needed now?

The issue of whether or not routine patellar resurfacing in total knee arthroplasty is necessary has been a considerable point of debate over the last 10 years. There is a wide variation in opinions from surgeons on the appropriateness of patellar resurfacing in TKA procedures. As such, an evidence base of randomized controlled trials is necessary to make recommendations on the practice.

What was the principal research question?

In total knee arthroplasty, is there any significant difference in short-term functional performance, mid-term pain, patient-reported disease-related quality of life and patient satisfaction between patients who received patellar resurfacing and patients who did not receive patellar resurfacing?

Study Characteristics -
74 patients, 60-75 years of age, scheduled for unilateral total knee arthroplasty due to primary knee osteoarthritis. Procedures were standardized, with all cases performed through a medial parapetallar approach, with tourniquet control and patellar eversion. A cemented cruciate-retaining prosthesis (Triathlon; Stryker) was used in all cases.
Resurfacing group: Patients underwent total knee arthroplasty with patellar resurfacing according the knee system used. (n=35; 33 available at 6 years) (Mean age: 68+/-4)
No resurfacing group: Patients underwent total knee arthroplasty without patellar resurfacing. (n=39; 36 available at 6 years) (Mean age: 69+/-4)
Primary outcome was pain on a visual analog scale. Secondary outcomes were the Knee Injury and Osteoarthritis Outcome Scale (KOOS) functional performance tests - including a chair stand test, a 20-meter walk test, knee bending in 30 seconds test, knee strength in extension and patient satisfaction on a 4-point scale.
Pain, patient satisfaction and the KOOS were assessed at 3 months, 12 months, and 6 years postoperatively. Functional performance and extension strength were assessed at 3 months postoperatively.

What were the important findings?

  • There was no significant difference in VAS pain scores at 6 years between the resurfacing group (11+/-14) and the no resurfacing group (10+/-15) (p=0.7). Results also did not significantly differ between groups at 3 or 12 months (all p>0.05).
  • There was no significant difference in the percentage of patients who reported satisfaction with their outcome at 6 years between the resurfacing group (31/33) and the no resurfacing group (34/36) (p=0.5). Results also did not significantly differ between groups at 3 or 12 months (all p>0.05).
  • No significant differences were observed in any of the KOOS subscales (Pain, Symptoms, ADL, Sport/Rec, QoL) at any follow-up time-point (all p>0.05); both groups demonstrated significant within-group improvement from preoperative scores for the KOOS subscales.
  • Groups did not demonstrate any significant differences in any of the functional performance tests at 3 months: Chair stand test (p=0.9); time taken for 20m walk test (p=0.5); number of steps taken in 20m walk test (p=0.5); number of knee bends performed in 30s (p=0.9).
  • Knee extension strength did not significantly differ between groups at 3 months (p=0.8).
  • None of the patients in the no-resurfacing group underwent a secondary operation for patellar resurfacing within the first 72 months.

What should I remember most?

In total knee arthroplasty, no significant differences between groups who underwent the procedure with and without patellar resurfacing were observed for short-term functional performance measures, or mid-term patient-reported outcomes of pain, satisfaction, and disease-related quality-of-life.

How will this affect the care of my patients?

The results of this study suggest that short- and mid-term results following total knee arthroplasty did not significantly differ based on whether the patella is resurfaced or not. Given the controversy among practitioners, and varying results from previous randomized controlled trials on the topic, subsequent large-scale trials are necessary to ultimately determine if outcomes of routine total knee arthroplasty are affected by different methods of addressing the patella.

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