Biomechanical comparative analysis of multiple small diameter fan-shaped and parallel core decompression for early osteonecrosis of the femoral head.

BACKGROUND

Multiple small diameter fan-shaped and parallel core decompression are the surgical procedure used to treat the early osteonecrosis of the femoral head. However, It is not known which method is more appropriate from biomechanical perspective. Therefore, we aimed to analyze the mechanical stability of different distribution parameters of the two drilling methods using finite element analysis.

METHODS

Ten finite element models were established, including different drilling number (three-hole, four-hole, five-hole, seven-hole and nine-hole) based on fan-shaped and parallel core decompression. The stress and strain of the proximal femur was calculated to evaluate the biomechanical stability.

RESULTS

Results showed that maximum equivalent stress in the entire structure, greater trochanter's lateral wall, and bone tunnels increased with more drill holes in both groups, following the order: three-hole < four-hole < five-hole < seven-hole < nine-hole. At the same hole count, fan-shaped core decompression had higher maximum equivalent stress in the greater trochanter's lateral wall, cortical bone tunnel, cancellous bone tunnel, and bone tunnel in the osteonecrosis area compared to parallel core decompression, with notable percentage increases in the cancellous bone tunnel (21.18%-585.71%). Additionally, fan-shaped drilling exhibited higher average stress and local strain, especially in the cancellous bone tunnel, whereas parallel drilling maintained lower stress and strain levels across most regions.

CONCLUSION

From a biomechanical perspective, multiple small-diameter parallel core decompression is superior to fan-shaped decompression, offering better stability and reduced stress concentration in the proximal femur for early femoral head osteonecrosis.