Objective:To evaluate clinical outcomes and complications of minimal invasive surgery for the treatment of elderly patients with fragility fracture of pelvis.Methods:Elderly patients with fragile pelvic fractures undergoing minimally invasive surgery and being followed up were retrospectively analyzed from January 2015 to December 2019.Based on the classification of pelvic fragile fractures(FFP), open reduction and internal fixation with pelvic anterior ring instability internal fixator(INFIX)plus posterior ring sacroiliac screw, or open reduction and internal fixation with iliac fossa approach, were performed for elderly patients with fragile pelvic fractures.The general data of all patients(age, sex, mechanism of injury)were recorded.Time from injury to operation, VAS(visual analogue scale)before and after operation, blood loss during operation, complications during hospitalization, time to ambulation, mortality, and Koval walking index at 2 year follow-up were recorded to evaluate clinical outcomes and complications of minimal invasive surgery for the treatment of fragility fracture of pelvis.Results:Thirty-two patients were followed up, including 11 males and 21 females, aged 65-88 years(76.9±5.5)years.The mechanism of injury was fall on the ground as a percentage of 59.4%(19/32), fall in the sitting position as a percentage of 25.0%(8/32), and 15.63%(5/32)had unknown history of trauma.The time from injury to operation was 3-36 days(9.6±3.3)days.There were 50.0%(16/32)type Ⅱ, 31.3%(10/32)type Ⅲ and 18.8%(6/32)type Ⅳ cases according to FFP classification.The mean blood loss during operation was(65.9±35.2)ml(range, 20-200 ml). The preoperative VAS score was 5-9 scores, with an average of(6.41±1.07)scores.The postoperative VAS score was 1-4(1.71±0.63). Average time from injury to operation was(9.6±3.3)days(range, 3~36). The incidence of complications during operation was 9.4%(3/32), including 1 case of gastrointestinal bleeding, 1 case of lower extremity deep vein thrombosis, and 1 case of superficial wound infection.Ambulation was at 4 weeks post-operation in 56.3%(18/32)cases, at 6 weeks post-operation in 31.3%(10/32)cases and at 8 weeks post-operation in 12.5%(4/32)cases.6.25%(2/32)patients died within 2 year follow-up.Koval walking index of the rest 30 patients included grade 1 in 46.9%(15/32)cases, grade 2 in 18.8%(6/32)cases, grade 3 in 6.3%(2/32)cases, grade 4 in 18.8%(6/32)cases and grade 6 in 3.1%(1/32)case(1 year after surgery, hemiplegia after cerebral infarction).Conclusions:Minimal invasive surgery achieves significant pain relief and early mobilization in patients with fragility fracture of pelvis.