Surgical Dislocation of the Hip and its Implications in Acetabular Fractures

Abstract

SUMMARY S urgical Hip Dislocation is a powerful technique employed by hip preservation surgeons for treatment of a variety of hip pathologies. The critical element of this approach is a detailed understanding of the blood supply to the femoral head, which takes its most important contribution from the deep branch of medial femoral circumflex artery (MFCA). In its extracapsular segment and as it travels superiorly, it crosses the tendon of obturator externus posteriorly and the conjoint tendon of gemellus inferior, obturator internus and gemellus superior anteriorly. Intact obturator externus is important surgically because it protects this branch from being stretched or disrupted during dislocation of the hip in any direction traumatically or surgically. Then, in intracapsular segment it runs along the posterosuperior aspect of the neck of the femur dividing into two to four superior retinacular vessels. The head can be completely perfused by the superior retinacular vessels alone without any other vascular input. The inferior retinacular, metaphyseal, lateral circumflex femoral and the artery of ligamentum teres contribute very little to the blood supply of head of femur. The hip joint can be surgically dislocated using other approaches. However, Ganz method of SHD has many advantages. It produces an anterior dislocation using low grade controlled trauma. The time of dislocation is much shorter than the six-hour limit which is thought to be critical after traumatic dislocations. All external rotator muscles are left intact and, therefore, protect the MFCA. Intraoperative monitoring of perfusion of the femoral head is possible. The abductor muscles are detached by trochanteric flip osteotomy and rigid fixation of the fragment restores immediate stability and allows for early mobilization of the patient. Surgical hip dislocation is a very versatile approach and can be used for a variety of procedures. It gives full access to the entire femoral head and acetabulum and allows unrestricted inspection of the joint. This technique is reserved for physically young patients with relatively severe deformities (Extensive, non-focal, or circumferential deformities) that are less suitable for arthroscopic treatment. Complex deformities associated with residual Perthes, SCFE, and post-traumatic disorders are also common indications for surgical dislocation. With this approach, surgeons are able to perform labral repair, resection of the acetabular rim, relative femoral neck lengthening, subcapital realignment in SCFE, proximal femoral osteotomies, femoral head reduction osteotomy as well as treatment of relatively uncommon conditions such as pigmented villonodular synovitis, synovial chondromatosis and osteochondromas of the femoral neck. The technique provides the surgeon an outstanding visualization of the entire acetabular and femoral surface therefore it has been employed to aid in anatomic reduction of selected acetabular and femoral head fractures. Also addresses marginal impaction of fractures, intra-articular assessment of fracture fragments, presence of intra-articular fragments, comminution of the posterior and superior wall, reduction of the associated anterior wall or anterior column fractures, extra-articular screws placement. Furthermore, it is possible to evaluate cartilage damage of the acetabulum and the femoral head as well as the perfusion of the femoral head. Surgical hip dislocation is technically demanding invasive procedure with high level of safety for femoral head perfusion. So meticulous execution of the surgical steps is important and it should be performed in tertiary care centers by surgeons with experience in hip preservation and with this technique specifically.