After an uneventful departure, climb, and cruise, the pilot performed a standard 45-degree entry into the traffic pattern at the high elevation airport. The airplane descended low during the final approach, and the pilot applied full forward throttle control. The engine responded; however, the descent was not arrested as he expected. The nose wheel then struck the airport perimeter fence, and the airplane came to rest against the side of the runway. The airplane sustained substantial damage to the firewall, lower fuselage, and right wing during the accident sequence. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation. The calculated density altitude for the runway elevation at the time of the accident was about 8,000 feet.