Session V - Femur
Operative Treatment of Femoral Neck Fractures in Adults Younger than 50
Purpose: The purpose of this review is to report results of operative fixation of femoral neck fractures in a large series of patients under age 50 years and identify risk factors for nonunion and osteonecrosis.
Methods: 125 patients with 128 femoral neck fractures (AO/OTA 31B) in patients ages 14 to 50 years (average 33.5 years) treated operatively during an 11.75-year period were retrospectively reviewed. 99 fractures (77%) were displaced, while 29 were valgus impacted or nondisplaced. Ipsilateral femoral shaft fractures were present in 47 (37%), the majority (n=32) with displaced femoral neck fractures. Implants included multiple large fragment screws in 105, DHS in 17, reconstruction nail in 4, and blade plate for 2. Patients were followed until healing or nonunion with a minimum of 3 months (median,15 months; range, 3 to 139 months).
Results: Fractures were classified as 31B1 in 9, 31B2 in 79, 31B3 in 36, and 31B in 4. Of the 29 nondisplaced or minimally displaced fractures, 23 were treated with either closed reduction and fixation or in situ fixation, while 6 were treated with open reduction and internal fixation (ORIF). Of the 23 fractures treated with a closed reduction, 6 had a documented percutaneous capsulotomy. None of these 29 fractures were complicated by nonunion or osteonecrosis. Of the 99 displaced fractures, 80 were treated with ORIF while 19 were treated with closed reduction and fixation. Of the 74 displaced fractures with adequate radiographs, the initial reduction was anatomic in 40 (54%), nearly anatomic in 21 (28%), and nonanatomic in 13 (18%). Nonunions were observed in 18 fractures (14%). Nonunion occurred in 0% of the 31B1, 14% of 31B2, and 17% of 31B3 patterns. No association was found between nonunion and AO/OTA classification, implant, or presence of ipsilateral shaft fracture. Nonunion was associated with initial displacement (P<0.01) and reduction (P<0.01). Nonunion was seen in 5 (13%), 5 (24%), and 7 (54%) of the anatomic, near anatomic and nonanatomic reductions (one with unknown reduction). Osteonecrosis occurred in 11 fractures; however, follow-up was short. 68 (53%) fractures were followed for >1 year, while only 39 (30%) for >2 years. Osteonecrosis was identified in 8 (22%) subcapital (31B3) fractures, compared to no 31B1, and 3 (4%) 31B2 fractures. Because most patients had a capsulotomy, no relationship with osteonecrosis or nonunion was seen.
Conclusions/Significance: The treatment of femoral neck fractures in is often driven by injury severity and ability to achieve an anatomic reduction. The only factors associated with the development of a nonunion were initial displacement and reduction. Initial displacement was also correlated with osteonecrosis as was fracture classification. These results suggest that every effort should be made to accurately reduce displaced femoral neck fractures in young adults.