Management of chronic lateral instability due to lateral collateral ligament deficiency after total knee arthroplasty: a case report.

INTRODUCTION: Lateral instability following total knee arthroplasty (TKA) is a rare condition with limited report of treatment options. The objective of this case presentation is to demonstrate the outcomes of different surgical procedures performed in a single patient with lateral collateral ligament (LCL) deficiency. CASE
PRESENTATION: We present a case of chronic lateral instability due to LCL deficiency after primary TKA in a 47-year-old Caucasian woman with an obesity problem. Multiple treatment options have been performed in order to manage this problem, including the following: ligament reconstruction; combined ligament reconstruction and constrained implant; and rotating-hinge knee prosthesis that was the most recent surgery. All ligament reconstruction procedures failed within one year. The varus-valgus constrained prosthesis provided stability for six years.
CONCLUSIONS: Ligament reconstruction alone cannot provide enough stability for the treatment of chronic lateral instability in patients with obesity problems and LCL deficiency. When the reconstruction fails, a salvage procedure with rotating-hinge knee is still available.