Similar long-term clinical and radiological outcomes with mobile- or fixed-bearings in TKA .
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)?
Sim = 1
Incerto = 0,5
Não relevante = 0
Não = 0
A Avaliação dos Critérios de Relato avalia a transparência com que os autores relatam as caraterísticas metodológicas e do ensaio na publicação. A avaliação está dividida em cinco categorias que são apresentadas de seguida.
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
O Índice de Fragilidade é uma ferramenta que auxilia na interpretação de achados significativos, fornecendo uma medida de força para um resultado. O Índice de Fragilidade representa o número de eventos consecutivos que precisam de ser adicionados a um resultado dicotómico para que o resultado deixe de ser significativo. Um número pequeno representa um resultado mais fraco e um número grande representa um resultado mais forte.
Porque é que este estudo era necessário agora?
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.
Qual era a principal questão de investigação?
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?
- 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.
De que é que me devo lembrar mais?
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.
Como é que isto afectará o tratamento dos meus doentes?
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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