Purpose: To evaluate outcomes in a single-surgeon series of ulnar shortening osteotomy for the treatment of traumatic isolated tears to the lunotriquetral interosseous ligament (LTIL)., Methods: This study includes 53 consecutive cases of posttraumatic isolated LTIL tears treated with ulnar shortening osteotomy with minimum 1-year follow-up (range, 1.0-10.6 y). We confirmed all LTIL tears via arthroscopy before performing a precision 2.5-mm oblique osteotomy using a modified Rayhack technique. We assessed outcomes using grip strength measurements and Chun and Palmer's modified Gartland Werley wrist scoring system, which includes subjective and objective outcome measures., Results: Preoperatively, 45 cases were graded as fair (28%; n = 15) or poor (57%; n = 30) on the modified Gartland Werley score. There were insufficient data to calculate grades in 8 cases (15%). At final follow-up, most patients exhibited excellent (51%; n = 27) or good (32%; n = 17) scores, some scored fair (17%; n = 9), and none scored as poor. All subjective and objective variables significantly improved over a mean follow-up of 36 months (range, 12-127 mo). Mean grip strength increased from a value of 23 kg before surgery to 33 kg over the same period, a 41% increase. All patients achieved clinical and radiographic union by 10 months. Osteotomy plates were removed routinely in most cases (89%; n = 47) at a mean of 17 months., Conclusions: Ulnar shortening osteotomy reduced symptoms of posttraumatic isolated LTIL tears in this single-surgeon series., Type of Study/level of Evidence: Therapeutic IV., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)