During the period of January 1, 1972 through October 31, 1982 seven knees in seven patients had ligamentous reconstructions for instability following total knee arthroplasty. The type of ligamentous instability included severe medial instability in six and a combined severe medial and mild lateral instability in one patient. The surgical technique utilized to reconstruct the ligaments included proximal and distal advancement of the medial collateral ligament. In five of the seven, additional soft tissue surgery was combined with tightening of the medial collateral ligament. Unfortunately, ligamentous reconstruction failed to restore stability to the knee in any of the seven patients. Four patients required revision total knee arthroplasty. Instability of the knee necessitated full-time support with a brace and the seventh patient manages his instability without a brace. Ligamentous reconstruction without component revision is inappropriate in the treatment of the unstable knee following total knee arthroplasty.