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 - osteoarthritis, knee - muscle strength
