[Evaluation of hemodynamic changes by digital subtraction angiography after treatment of avascular osteonecrosis of femoral head with vascularized bone flaps].

Objective: To evaluate the effect of digital subtraction angiography (DSA) in evaluation of the hemodynamic changes after treatment of avascular osteonecrosis of femoral head with vascularized bone flaps.

Methods: Fifty-four patients, 33 males and 21 females, 33 hips being at the stage II and 21 hips being at the stage III, were treated with vascularized bone flaps, including iliac bone flaps pedicled with ascending branch of lateral femoral circumflex artery for 23 hips, greater trochanter bone flaps pedicled with gluteal muscle branch of ascending branch of lateral femoral circumflex artery for 13 hips, greater trochanter bone flaps pedicled with transverse branch of ascending branch of lateral femoral circumflex artery for 9 hips, and greater trochanter bone flaps pedicled with gluteal muscle branch and transverse branch of ascending branch of lateral femoral circumflex artery for 9 hips. Selective DSA was performed on all 54 patients pre-operatively and on 19 patients 6-24 months post-operatively.

Results: DSA before operation demonstrated abnormal vascularization in all 54 patients. Six months after operation reconstruction of blood supply on the femoral head was seen in 48 cases. Six patients showed poor filling or failure of filling of the vessel pedicles in transplanted bone flaps 6 months post-operatively and DSA conducted 8 months postoperatively showed satisfactory filling in one of the 6 cases. The clinical success rate of this group was 91%, and the radiological success rate was 85%.

Conclusion: Selective DSA is effective in evaluation of the postoperative hemodynamic changes in the necrotic femoral head. Significant blood supply in the bone flap is the key point in the success of treatment of ONFH.