Young patients undergoing THA or hip used. HOS and iHOT33 have demonstrated to be useful in hip preservation surgery but never used in THA. The aim of the study was to evaluate long-term clinical outcomes with HOS and iHOT33 in hip arthroscopy and THA We conducted a retrospective study with prospective data collection of 118 consecutive young patients (<65 y.o.) between 2008 to 2012 who underwent hip arthroscopy or THA. The mean follow-up was 12.05 years. All surgeries were done by the same senior surgeon. PROMs used were iHOT-33 and HOS preoperatively, at one year and 10 years. SPSS Statistics Grad Pack 28.0 software was used for statistical analysis Arthroscopy Group (57 patients): Mean age 35.36 years. 55.93% were male. iHOT33 mean differential improvement was 24.43 at 1 year, 70,17% exceed MCID and 49,1% SCB. HOS mean differential improvement was 16.26 at one year. 54,38 % patients exceed MCID and 49,36% SCB. At 10 years, iHOT33 mean differential improvement was 14,36 and 12.56 for HOS. Regarding complications, 3 patients underwent THA (5.26%) and 10 (17.54%) continued with groin pain. THA Group (61 patients): Mean age 52,54 years. 55.73% were male. Cementless THA was used in all patients with ceramic on ceramic used in 77%. iHOT33 mean differential improvement was 41,57 at 1 year. 95,08% patients exceed MCID and 85,25% SCB. HOS mean differential improvement was 16.57 points at one year. 85,25% patients exceed MCID and 81,97% SCB. At 10 years, iHOT33 mean differential improvement was 20,15 and 14.12 for HOS. Regarding complications, 1 patient underwent DAIR for infection (1.64%) and 1 dislocation with close reduction (1.64%). iHOT33 or HOS scores should be considered to be used in young active patients after hip preserving surgery or THA, with more predictable results at long-term in THA group.