Prevention of motor ascending branch of the rectus femoris injuries in Bernese periacetabular osteotomy: a cadaveric study

The Bernese periacetabular osteotomy (PAO) is a surgical procedure used to treat hip dysplasia in young adults, but it carries the risk of neurological complications, including injury to the motor ascending branch of the rectus femoris (MABRF). This study aimed to describe anatomical considerations to prevent MABRF injuries during PAO. A cadaveric study was conducted on seven specimens. The original and modified PAO approaches were used, with and without disinsertion of the rectus femoris muscle origin. The femoral nerve was dissected in all specimens from the endopelvic position to the MABRF origin (T-point). The average distance from the anterosuperior iliac spine to the T-point was 10.2 ± 0.4 cm. To protect the MABRF, a safety zone was identified for the osteotome placement during the ischial cut. The osteotome was slid over the joint capsule, deflecting the iliocapsularis muscle medially and distally. This manoeuvre shields the MABRF with the iliocapsularis muscle, reducing the risk of neurological injury. Both the original and modified PAO approaches were considered safe techniques with low risk to the rectus femoris innervation. These findings offer valuable insights for surgeons performing PAO, emphasizing the significance of understanding anatomical relationships and implementing protective measures to enhance patient outcomes and minimize complications. In conclusion, implementing these anatomical considerations can help prevent MABRF injuries during PAO, contributing to safer and more successful surgical interventions for hip dysplasia in young adults.