 The purpose of this study is to prospectively compare the outcomes of patients with severe intrinsic hand muscle dysfunction compressive ulnar neuropathy at the elbow treated with ulnar nerve decompression and subcutaneous transposition alone versus ulnar nerve decompression with subcutaneous transposition and AIN to ulnar nerve reverse end-to-side transfer. The study objectives of this project are the following: 1. To prospectively compare the clinical outcomes of patients with severe ulnar neuropathy at the elbow who receive ulnar nerve decompression with subcutaneous transposition and AIN to ulnar motor reverse end-to-side nerve transfer versus decompression and subcutaneous transposition alone. 2. To prospectively compare the electrophysiologic outcomes nerve conduction studies and EMG of patients with severe ulnar neuropathy at the elbow who receive ulnar nerve decompression with subcutaneous transposition and AIN to ulnar motor reverse end-to-side nerve transfer versus decompression and subcutaneous transposition alone. 