Randomized controlled trial investigating the benefits of microprocessor controlled knee prostheses (MPK) in patients with a transfemoral or knee disarticulation level amputation categorized by Medicare Functional Classification Level (MFCL) as a Limited Community Ambulator (K-Level 2). There are two aims for the study. Aim 1 is to understand the effect of MPK technology for the K2 ambulator on reducing fear and anxiety of falling, improving health-related quality of life, and participation in society and activities. Aim 2 is to understand the long-term effect of MPK technology the aspects from Aim 1 as well as reducing morbidity. The trial will be conducted in two phases. Phase 1 will cover the initial 12-month period to address Aim 1, and phase 2 will monitor from 12 months to 5 years to address Aim 2.