AbstractBackground: Undisplaced femoral neck fractures are usually treated with internal fixation. Few studies have investigated the postoperative physical function and quality of life of these patients. The objective of this retrospective study was to study hip function and health related quality of life of patients treated with internal fixation for undisplaced femoral neck fractures. Postoperative radiographs of the healthy as well as the affected hip were assessed and healing and femoral neck shortening were noted. Healing in a non-anatomical position was studied in regard to physical function and quality of life.Results: 54 patients with a median age of 80 years operated at Ullevål University hospital in the period 1.1.2009 – 31.12.2010 met the inclusion criteria. 13 patients died during the follow up time of 1-24 months. 35 survivors were contacted by phone and questioned with modified Harris Hip Score and Eq-5d (Euroqol). 58 % stated that they had “moderate pain or discomfort” when answering Eq-5d questionnaire. When affected and healthy hip were compared on radiographs taken in average four months after surgery, average femoral neck shortening was 10 %. Patients with the femoral neck healed in “non-anatomical position” had a tendency to lower scores on modified HHS and EQ5D index score and VAS than patients with the femoral neck healed in “good anatomical position”. Modified HHS was best in discriminating between the two groups.Conclusion: A randomized controlled trial comparing undisplaced fractures treated with internal fixation vs arthoplasty should be the next step to follow up this topic.