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BackgroundTreatment for osteonecrosis of the femoral head (ONFH) in young individuals remains controversial. We developed a lantern-shaped screw, which was designed to provide mechanical support for the femoral head to prevent its collapse, for the treatment of ONFH. The purpose of this study was to investigate the efficacy and safety of the lantern-shaped screw loaded with autologous bone for the treatment of pre-collapse stages of ONFH.MethodsThirty-two patients were randomly divided into two groups: the lantern-shaped screw group (core decompression and lantern-shaped screw loaded with autogenous bone) and the control group (core decompression and autogenous bone graft). During 36 months follow-up after surgery, treatment results in patients were assessed by X-ray and computed tomography (CT) scanning as well as functional recovery Harris hip score (HHS).ResultsSuccessful clinical results were achieved in 15 of 16 hips (94%) in the lantern-shaped screw group compared with 10 of 16 hips (63%) in the control group (p = 0.0325). Successful radiological results were achieved in 14 of 16 hips (88%) in the lantern-shaped screw group compared with 8 of 16 hips (50%) in the control group (P = 0.0221).ConclusionThe lantern-shaped screw loaded with autologous bone for the treatment of pre-collapse stages of ONFH is effective and results in preventing progression of ONFH and reducing the risk of femoral head collapse.Trial registrationThe trial registration number: ChiCTR-TRC-13004078 (retrospectively registered at 2013-11-28).

Implants currently used for reconstruction of a burst vertebral body are associated with complications, including subsidence, nonunion, and substantial intraoperative blood loss. A new reconstruction device, the U-Cage (Double Engine Medical Material Ltd, Xiamen, Fujian, China), was designed to minimize complications.Six intact adult cadaver thoracolumbar (T11-L3) spines were collected and scanned by dual-energy X-ray absorptiometry (DEXA). The stiffness of the burst spine was subsequently compared with its previous intact state during flexion/extension, lateral bending, and rotation, and then subjected to a cyclic test to predict cage subsidence and device loosening. Axial load was applied continuously until failure to test the peak load that the specimen could withstand during the cyclic test. The correlation of bone mineral density and peak load was also analyzed. The instrumented specimens were found to be equivalent to intact bone in all directions (P>.05), with the exception of left rotation (P<.05). All specimens could withstand the cyclic test, and no subsidence or loosening of the device was detected. Average peak load for the instrumented specimens was 4137.5 N, which correlated with the average bone mineral density (r=0.915; P=.011).Thoracolumbar burst fractures instrumented with a U-Cage and anterolateral D-rod fixation achieved a stiffness similar to that of intact spines. This procedure may avoid the subsidence of the cage in vivo and serve as a better option for treating thoracolumbar burst fractures.