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.