Comparative Functional and Isokinetic Analysis between Implants with Posterior Stabilization and Rotating Hinge Total Knee Arthroplasty

Abstract

Objective : To compare the function and muscle strength of the limb between patients undergoing knee arthroplasties using primary implants with posterior stabilization (control group) and patients with rotating hinge implants (Hinge group). Methods : Function assessment was performed using the Knee Society Score (KSS) and muscle strength using an isokinetic dynamometer using a speed of 60°/s. Results : 43 patients were analyzed, who underwent 51 surgeries, with the Hinge group comprising 25 surgeries and the control group comprising 26 primary surgeries. We did not observe significant differences between the Hinge and control groups in the values of functional KSS (p = 0.54), objective KSS (p = 0.91), peak flexor torque (p = 0.25) and peak extensor torque (p = 0.08). Patients in the Hinge group who underwent primary arthroplasties had a higher peak flexor torque (0.76 Nm/kg) than those who used the implant in revision after septic failure (0.33 Nm/kg) (p < 0.05). The constrained implant was indicated in arthroplasty revision surgeries with severe ligament instability and in cases of complex primary arthroplasties with bone destruction or severe coronal deformity in the coronal plane. Conclusion : The use of constrained implants enables joint function and muscle strength comparable to patients who underwent primary arthroplasty using conventional implants with posterior stabilization. Patients undergoing septic revision with a rotating Hinge prosthesis exhibit lower flexor muscle strength compared to those undergoing primary arthroplasty with a constrained implant.

Keywords: arthroplasty, replacement, knee; muscle strength; osteoarthritis, knee.

Fig. 1

Functional and objective clinical scores (KSS) of patients undergoing total knee arthroplasty with Hinge-type prosthesis (Hinge: dark gray) and with prosthesis with posterior stabilization (Control: light gray). KSS represented in dots. SD = Standard deviation. Mann-Whitney test. "x" indicates mean. Lines indicate median and interquartile ranges. ● indicate individual patient values.

Fig. 2

Functional and objective clinical scores (KSS) of patient subgroups who used the constrained Hinge prosthesis. KSS represented in dots, ANOVA test performed. Dark Gray = Primary TKA. Light Gray = Septic Revision. Striped = Aseptic Revision. "x" indicates mean. Lines indicate median and interquartile ranges. ● indicate individual patient values.

Fig. 3

Extensor and flexor torque peak of patients undergoing total knee arthroplasty with Hinge-type prosthesis (Dark Gray) and with prosthesis with posterior stabilization (Control: Light Gray). Peak torque represented in Newton meter / kilo. Mann-Whitney test. "x" indicates mean. Lines indicate median and interquartile ranges. ● indicate individual patient values.

Fig. 4

Peak extensor and flexor torque of patient subgroups who used the Hinge-type prosthesis. Peak torque represented in Newton meter / kilo. ANOVA test. * p < 0,05 Dark Gray = Primary TKA. Light Gray = Septic Revision. Striped = Aseptic Revision. "x" indicates mean. Lines indicate median and interquartile ranges. ● indicate individual patient values.

Fig. 1

Escore clínico funcional e objetivo (KSS) dos pacientes submetidos a artroplastia total do joelho com prótese tipo Hinge (Hinge: cinza escuro) e com prótese com estabilização posterior (Controle: cinza claro) KSS representado em pontos. DP = Desvio padrão. Teste de Mann Whitney “x” indica média. Linhas indicam mediana e intervalos interquartílicos. ● indicam os valores individuais dos pacientes.

Fig. 2

Escore clínico funcional e objetivo (KSS) dos subgrupos de paciente que utilizaram prótese constrita Hinge. KSS representado em pontos, realizado teste ANOVA. Cinza Escuro = ATJ Primária. Cinza Claro = Revisão Séptica. Listrado = Revisão Asséptica. “x” indica média. Linhas indicam mediana e intervalos interquartílicos. ● indicam os valores individuais dos pacientes.

Fig. 3

Pico de torque extensor e flexor dos pacientes submetidos a artroplastia total do joelho com prótese tipo Hinge (Cinza escuro) e com prótese com estabilização posterior (Controle: Cinza claro) Pico de torque representado em Newton metro / quilo. Teste de Mann Whitney “x” indica média. Linhas indicam mediana e intervalos interquartílicos. ● indicam os valores individuais dos pacientes.

Fig. 4

Pico de torque extensor e flexor dos dos subgrupos de paciente que utilizaram prótese tipo Hinge Pico de torque representado em Newton metro / quilo. Teste ANOVA. * p < 0,05 Cinza Escuro = ATJ Primária. Cinza Claro = Revisão Séptica. Listrado = Revisão Asséptica. “x” indica média. Linhas indicam mediana e intervalos interquartílicos. ● indicam os valores individuais dos pacientes.