gms | German Medical Science

Objectives: Hip fractures in the elderly population are common and the number of patients is rising. For young patients and geriatric patients with undisplaced fractures osteosynthesis is the primary type of treatment. The dynamic hip screw (DHS) is around for many years and proved its value especially in displaced fractures. Since 2018 the femoral neck system (FNS) is available as an alternative showing promising biomechanical results. Aim of this study to evaluate clinical results of the FNS and compare it to the DHS.

Methods: Patients older than 18 years with Garden I-IV fractures that were treated with osteosynthesis in a level 1 trauma center were included in the study. 113 patients were treated with FNS (1-hole plate, DePuy-Synthes, Zuchwil, Switzerland) and compared with 108 patients treated with DHS(2-hole plate, DePuy-Synthes, Zuchwil, Switzerland). Closed reduction was achieved using a traction table. All operations were carried out or supervised by an experienced orthopedic trauma surgeon. Primary outcome measure were rate of implant failure (cut out) and surgical complications (hematoma, infection). Secondary outcome measures were Hb-difference, length of hospital stay and mortality.

Results and conclusion: Overall mean age was 69+/-14 years and there were 17.2% garden I, 47.5% garden II, 26.7% garden III and 8.6% garden IV fractures.There was no difference between the groups for age, BMI, time to surgery, AO-, Pauwels and Garden classification, rate of optimal blade position or tip apex distance. FNS showed lower pre- to postoperative Hb-difference (1.4+/-1.1g/l vs 2.1+/-1.4g/l; p<0.05), shorter operating time (36.3+/-11.6min vs 54.7+/-17.4min; p<0.05) and hospital stay (8.8+/-4.3d vs 11.2+/-6.8d ;p< 0.05). Surgical complications (FNS 13.3% vs DHS 16.7%, p >0.05), rate of cut out (FNS 12.4% vs DHS 10.2%, p>0.05) and mortality (FNS 3.5%; DHS 0.9%; p>0.05) showed no difference between the groups. Logistic regression showed that poor blade position was the only significant predictor for cut out and increased the risk by factor 7. Implant related infection(n=3) and hematoma/seroma (n=6) was only seen in DHS-group.

FNS proved to be as reliable as DHS in all patients with hip fractures. Not the type of implant but blade positioning is still key to prevent implant failure. Still due to minimal invasive approach implant related infections and postoperative hematomas might have been prevented using the FNS.