ARTHROPLASTY
Mobile vs fixed-bearing total knee arthroplasty performed by a single surgeon: a 4- to 6.5-year randomized, prospective, controlled, double-blinded study
OrthoEvidence Journal (OE Journal) - ACE Report
OE Journal. 2014;2(6):6 J Arthroplasty. 2013 Dec;28(10):1712-6. doi: 10.1016/j.arth.2013.01.003. Epub 2013 Mar 23.56 patients undergoing unilateral total knee arthroplasty (TKA) were randomized to compare the clinical and radiological outcomes, as well as the safety, of two types of bearing systems. Patients underwent TKA using either a mobile- or fixed-bearing system (Scorpio + Single Axis and Duracon systems, respectively). Results at a final follow-up of 4-6.5 years indicated that most of the clinical outcomes were similar when TKA was performed using either a mobile- or fixed-bearing system, with the exception of range of motion, which favoured the mobile-bearing group. Radiological outcomes, patient satisfaction and the incidence of complications were also statistically similar between groups. Furthermore, the survival rate was 100% using both techniques.
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)?
はい = 1
不確実=0.5
無関係 = 0
いいえ = 0
報告基準評価では、著者が出版物内で試験の方法論的特徴や試験特性を報告する際の透明性を評価します。評価は以下の5つのカテゴリーに分類されます。
2/4
Randomization
3/4
Outcome Measurements
4/4
Inclusion / Exclusion
4/4
Therapy Description
4/4
Statistics
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
Fragility Indexは、重要な所見の解釈を助けるツールで、結果の強さの尺度を提供します。Fragility Indexは、その所見が有意でなくなるために、二項対立の結果に追加する必要がある連続した事象の数を表します。数値が小さいほど弱い所見を表し、数値が大きいほど強い所見を表します。
なぜ今この研究が必要なのですか?
Total knee arthroplasty (TKA) procedures have traditionally used prostheses comprised of fixed bearings. With the hopes of improving knee kinematics post-surgery, researchers have proposed the use of mobile bearings as an alternative in these procedures. Many studies comparing this relationship (i.e. mobile vs. fixed bearings) have found no significant differences in the clinical and radiological outcomes following TKA. Furthermore, there are no follow-up studies comparing the Scorpio + Single Axis system for mobile-bearing knee prostheses to the Duracon system for fixed-bearing knee prostheses (both Stryker Howmedica Osteonics, Allendale, New Jersey). This study compared mid-term clinical and radiological results obtained using the Duracon versus the Scorpio + Single Axis system.
主な研究課題は何ですか?
Does a mobile-bearing system (Scorpio + Single Axis system) yield better clinical and radiological outcomes, when compared to a fixed-bearing system (Duracon system), in patients undergoing total knee arthroplasty, at a 4- to 6.5-year follow-up?
重要な知見は?
- At final follow-up, there were no significant between-group differences in OKS scores (MB group: 16.6 +/- 1.0 points; FB group: 17.9 +/- 1.4 points; p=0.312) or pain scores (MB group: 44.1 +/- 3.4 points; FB group: 46.4 +/- 3.3 points; p=0.296).
- KSS scores were also statistically similar in the mobile-bearing (173.9 +/- 10.5 points) and fixed-bearing (161.2 +/- 8.7 points) groups at final follow-up (p=0.059). Similar results were observed for the KSFS (p=0.060) and KSKS (p=0.365) subsets of the KSS assessment tool.
- Range of motion (ROM) at final follow-up was 125.3 and 110.4 degrees in the mobile- and fixed-bearing group, respectively. This was a statistically significant difference (p=0.016).
- In the mobile-bearing group, 72% of patients could sit cross legged, 48% could sit on the floor, and 17% could squat, while in the fixed-bearing group, these percentages were 19%, 7% and 0%, respectively.
- All radiological outcomes (knee alignment, position of the femoral and tibial components in the sagittal and coronal planes, and the shift in joint line) were similar between groups (p>0.05). There were no radiolucent lines seen in any knee throughout the study.
- All patients who received TKA with the fixed-bearing system were satisfied with the procedure, whereas 2 patients in the mobile-bearing group reported dissatisfaction with the procedure (stating it was due to their inability to squat). The difference in patient satisfaction was not significant (p=0.14).
- 3 patients in the mobile-bearing group and 4 patients in the fixed-bearing group reported anterior knee pain when rising from a chair or climbing stairs (p=0.49). In addition, 5 patients in the mobile-bearing group and 0 patients in the fixed-bearing group reported an asymptomatic clicking sensation in the knees.
- No complications were reported in either group. Furthermore, the Kaplan-Meier survival rate was 100% in both groups at final follow-up.
最も覚えておくべきことは?
Most of the clinical outcomes were similar at final follow-up when total knee arthroplasty (TKA) was performed using either a mobile- or fixed-bearing system, with the exception of range of motion, which was greater in the mobile-bearing group. Radiological outcomes, patient satisfaction and the incidence of complications were also statistically similar between groups. Furthermore, survivorship at a follow-up between 4 and 6.5 years was 100% using both techniques.
それが私の患者ケアにどのように影響するか?
Although the use of a mobile-bearing system in total knee arthroplasty (TKA) provides some clinical benefits over a fixed-bearing system, most clinical outcomes are comparable between the two. The use of mobile- and fixed-bearing systems also yields similar safety and radiological outcomes. Additional long-term studies are needed, however, to compare these two systems in terms of polyethylene wear and periprosthetic osteolysis.
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