A satisfactory treatment for osteonecrosis of the femoral head in patients with SLE remains elusive.Without operative intervention ONFH could result in collapse and deterioration of the joint. Some scholars reported(17) a 53% rate of progression to collapse of the femoral head articular surface in 79 hips treated nonoperatively.Current treatment options include core decompression, various osteotomy techniques and vascularized bone graft(18-21).
Core decompression provides pain relief,especially for patients with earlier stages of avascular necrosis(22).There is evidence that core decompression is an effective intervention in lupus patients with Ficat stage I and II.Several studies report , failure of core decompression and progression of osteonecrosis in lupus patients, especially in patients with Ficat stage III(23). Maniwa(24) have evaluated the results of core decompression for osteonecrosis of the hip in patients with SLE. The report suggest that patients with avascular necrosis of the femoral head and lupus do not respond as well as nolupus patiens treated with core decompression.
In 1978, Sugioka(25) first introduced rotary osteotomy through greater trochanter of femur to treat ONFH,which was intertrochanteric osteotomy of the femoral head necrosis rotation. The principle is the upper part of the front of the femoral head necrosis is transferred to the non-load-bearing parts, in order to prevent progressive collapse of the articular surface of the femoral head, and correct head and acetabulum mismatch caused by subluxation occured after the collapse of the articular surface of the femoral head. Then a variety of improved surgical procedures used in clinical, there is a big difference in the reported results. Although it is considered this kind of surgical mothod can prevent the collapse of the new weight-bearing area, but increased the incidence of instability and the corresponding joint osteoarthritis. Due to the high incidence of this surgical complication and followed by deformity of the proximal femur, the clinical application is limited. Greater trochanter of femur mainly comprised by spongy bone, have rich blood supply, bone flap have large range blood supply, the blood supply in the affected areas can be improved effectively after transplantation, the rebuilding process of the blood supply can be shortened.
The use of the free fibular flap for the treatment of ONFH was initiated in an effort to enhance revascularization and arrest the progression of the necrosis.Soucacos(26) reported using free vascularized fibular grafting for osteonecrosis of the femoral head in 184 hips, a mean follow-up of 11 years, only 7.6% of patients requiring total hip arthroplasty, and 62% patients without progression.However, the procedure of free fibular flap transfer is technical demanding and time consuming.Moreover, complications associated with the use of fibular flap, such as donor-site pain, peroneal nerve neuropathy and fracture of the femoral neck, have also been reported(27, 28).
The greater trochanter bony structure with cancellous bone, peripheral rich blood supply, transplantation can effectively improve the blood supply, reduce blood supply reconstruction process.The thin cortical bone is very similar to head of femur, is ideal selected area to treat ONFH; and is able to improve the mechanical properties of necrosis of the femoral head effectively. After removing the necrotic bone completely, the transferred greater trochanter and the remaining part of femoral metastases fit closely to promote fracture healing process; greater trochanter and femoral trabecular bone trabecular have same nature, which restored the continuity of cancellous bone trabecular, rebuilding the supporting role of trabecular bone of the femoral head, to recovey femoral neck bearing bracket, can be adapted to load normal joint activities; meanwhile as the cystic degeneration repair and new bone reconstruct, the femoral head restoring the force area, so that the stress beared by unit trabecular bone area reduced, the mechanical properties of the femoral head strengthened, preventing the collapse effectively. In addition, the vascularized bone flap can reconstruct a new blood supply system, accelerate the repair and rebuilding of bone necrosis, thereby restoring the biological characteristics of the femoral head necrosis. And by mechanics, we proved the cut of the greater trochanter does not damage the mechanical properties and structure of the proximal femur trochanter major stress conductive zones, thus from a mechanical point of view, the selection of bone flap from the greater trochanter is safe and feasible. The bone flap transplantation located in front of the femoral neck, this area is a region of low stress distribution, can reduce the impact on the mechanical characteristics of the proximal femur. This provides bone flap entering the channel and select specific operative incision from femur head and neck in greater trochanter vascularized bone grafting a strong theoretical basis, but also proves the safety of this surgical technique, and fewer complications.
On the use of vascularized the greater trochanteric bone flap graft treating 26 hips with secondary ONFH caused by SLE, by an average of 32 months of follow-up,medium-term clinical results were satisfactory,the excellent and good rate was 88.5% , this surgery can slow down or even stop the progress of ONFH. During follow-up, femoral head necrosis increasing with the progression of stage in two patients, DSA angiography showed: blood filling poorly in vascularized bone or no contrast agent filling the femoral head, maybe caused by the twist or spasm of the vascular pedicle, or constriction from surrounding tissue swelling, until to the last follow-up, both patients have no other further treatment requirements in addition to functional rehabilitation treatment.
But we are also aware of some limitations of our study. First, we had no control group treated with alternative joint-preserving procedures. Second, the length of follow-up is only 32 monthes. Longer term outcome analysis will be necessary to prove the longevity of the procedure. Third, the current study has only 26 hips; therefore, significant statistical conclusions are more difficult to make.