Total knee arthroplasty represents a well-established and successful procedure; however, ligament incompetence is known to negatively affect surgical outcomes. Here we present an unusual case of early total knee arthroplasty failure secondary to femoral posterior cruciate ligament (PCL) avulsion and associated lateral collateral ligament (LCL) tear, treated successfully with primary PCL repair and LCL reconstruction. For LCL reconstruction, a peroneus longus allograft was passed through an anterior to posterior bony tunnel in the fibular head and docked into a horizontal femoral tunnel. Level of evidence Case report, Level IV.