A computer-assisted navigation technique for complex primary knee arthroplasty with intra-articular bone defect and instability: A case report and literature review

Abstract

Correction of a combined severe varus, bone defect, and ligamentous instability in a complex primary knee replacement is a technically demanding procedure. In such instances, constrained or rotating-hinge prosthesis is usually considered. Computer-assisted surgery in extra-articular deformity correction is a widely accepted and advantageous approach, but difficult to apply for intra-articular deformity due to difficulties with defining anatomical references. Our case report describes a patient with severe osteoarthritis, with intra-articular bone defects and ligament instability. We performed a computer-assisted navigation technique by combining gap balancing and measured resection techniques, with a metaphyseal sleeve as a new joint-line reference. We used an unconstrained posterior-stabilized (PS) prosthesis, incorporating Knee Society Scores (KSS): KSS-knee and KSS-function improved from 0–91 and 5–85, respectively, at one-month postoperatively. Our technique exhibited good short-term clinical outcomes and may decrease the requirement for constrained or rotating-hinge prostheses in a complex primary case.