Femoral Neck Osteotomy

The indication for upper intertrochanteric (ITO) and subtrochanteric (STO) femoral osteotomies is becoming less frequent due to the favourable results of total hip replacements even when implanted in rather young adults. In contrast to total hip arthroplasty (THA), the outcome of hip osteotomies can be unpredictable, especially when performed for established osteoarthritis. In addition to this, classic hip osteotomies are burdened with undesired side effects including limb shortening, abductor weakness, extra-articular impingement, local pain from hardware, and more complicated conversion to THA. Using the rather safe surgical hip dislocation (SHD) and the extended retinacular flap technique, the femoral neck area can be approached without interfering with the femoral head perfusion. The osteotomy level can be moved closer to the joint, avoiding or minimizing most side effects of intertrochanteric or subtrochanteric osteotomies. Current indications to perform a femoral neck osteotomy (FNO) include severe valgus deformities, deformities resulting from slipped capital femur epiphysis (SCFE), irregularities of the head contour and post-traumatic deformities. In some complex morphologies, it can be combined with a periacetabular osteotomy (PAO). True femoral neck osteotomy (FNO) is the surgical technique that enables intra-articular corrections at the level of the femoral neck. It can be performed using the surgical hip dislocation and the extended retinacular techniques (see Chaps. 7 and 8 ). It allows for a larger correction when compared to more distal osteotomies (see Chap. 15 ) as the osteotomy line lies closer to the femoral head. In addition, adverse side correction effects such as limb shortening and secondary deformity affecting total hip arthroplasty are minimal. The extraordinary good results are faced with a demanding technique. The risk of complications such as avascular necrosis or delayed union is linked to inadequate indication, poor detailed knowledge of the vascular anatomy, imprecise surgical technique, and lack of experience.