Revascularization in nontraumatic osteonecrosis of the femoral head

Joint-preserving effect and patient-reported outcomes of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head

BACKGROUND

This study assessed the hip survival rate and patient-reported outcome measures (PROMs) of transtrochanteric curved varus osteotomy (CVO) for osteonecrosis of the femoral head (ONFH) compared with those of conservative management.

METHODS

The CVO group comprised 32 consecutive patients (39 hips) who underwent CVO for ONFH between 2000 and 2011. The conservative group consisted of 36 consecutive patients (37 hips) who were managed conservatively for at least 1 year after collapse and who had ONFH classified by the Japanese Investigation Committee of Health and Welfare as type B or C1, for which CVO is indicated. Kaplan-Meier analysis of hip survival used any ONFH-related therapeutic surgery as the endpoint. PROMs were evaluated for all patients with surviving hips and radiographs available at the latest follow-up.

RESULT

The 10-year hip survival rate in the CVO group was 86.7%, which was significantly higher than the 51.0% 5-year survival rate in the conservative group (p < 0.0001). The Oxford Hip Score and UCLA Activity Score were significantly better in the CVO group without joint space narrowing than in the conservative group, with no significant differences between the CVO group with joint space narrowing and the conservative group.

CONCLUSION

CVO could preserve hip joints more effectively than conservative follow-up after collapse, although the presence of joint space narrowing could reduce satisfaction levels even in patients with long-term hip survival.

High-Degree Valgus Osteotomy for Severe Femoral Head Osteonecrosis After Femoral Neck Fracture with Nonunion: A Case Report

CASE

A 15-year-old adolescent boy had severe groin pain because of extensive osteonecrosis of the femoral head with collapse, joint space narrowing, and nonunion after a failed internal fixation for femoral neck fracture. We performed a 60° valgus osteotomy that moved the posteromedial small viable portion of the femoral head to the weight-bearing acetabular area. The femoral neck nonunion and the necrosis healed completely, and the spherical contour of the femoral head was regained after postoperative hip joint remodeling.

CONCLUSIONS

Good remodeling and congruency were achieved by performing high-degree valgus osteotomy to obtain sufficient viable area below the acetabular roof.

Effects of anterior boundary of the necrotic lesion on the progressive collapse after varus osteotomy for osteonecrosis of the femoral head

BACKGROUND

Anterior localization of the necrotic lesion was recently proposed as an important factor for the occurrence of collapse even in medially located osteonecrosis of the femoral head (ONFH). We examined the effects of the anterior boundary of the necrotic lesion on progressive collapse after varus osteotomy for ONFH.

METHODS

We reviewed the outcomes of 31 hips in 27 patients with ONFH treated by transtrochanteric curved varus osteotomy (CVO) from 2000 to 2012 with a mean follow-up of 10.5 years. The occurrence of progressive collapse of the anterior necrotic lesion was defined as the presence of ≥2 mm collapse using follow-up lateral radiographs. Postoperative osteoarthritic change was defined as ≥1 mm progression of joint space narrowing on follow-up radiographs. The location of the anterior boundary of the necrotic lesion was assessed using the anterior necrotic angle (the angle between the midline of the femoral neck shaft and the line passing from the femoral head center to the anterior boundary of the necrotic lesion on a mid-slice oblique magnetic resonance image).

RESULTS

All hips had a postoperative intact ratio of ≥34% (percentage of the transposed intact articular surface of the femoral head to the weight-bearing area of the acetabulum after femoral osteotomy). Progressive collapse of the anterior necrotic lesion was seen in five hips (16%) during a mean of 2.2 years after CVO. Of these, four hips (80%) proceeded to develop osteoarthritic change at an average of 4.3 years after the collapse. Multivariate analysis revealed that the anterior necrotic angle was independently associated with progressive collapse of the anterior necrotic lesion as well as the postoperative intact ratio.

CONCLUSIONS

This study suggests that hips with anterior localization of the necrotic lesion have a possible risk of progressive collapse of the anterior necrotic lesion after CVO, which can frequently lead to subsequent osteoarthritic change.

Effect of collapse on the deformity of the femoral head-neck junction in osteonecrosis of the femoral head

INTRODUCTION

The purpose of this study was to morphologically assess the effect of collapse on the deformity of the femoral head-neck junction in patients with nontraumatic osteonecrosis of the femoral head (ONFH).

MATERIALS AND METHODS

From January 2005 through March 2016, magnetic resonance (MR) imaging including the oblique view was repeatedly performed before and after collapse in 24 hips of patients with ONFH (16 men, 8 women; mean age 43 years; range 23-68 years), that were the subjects of this study. The interval of MR imaging before and after collapse was 8.0 months (range 1-32 months). In addition, 82 asymptomatic hips in patients without ONFH as identified by MR imaging taken at the same duration were used as controls. The oblique MR image was used to measure the radiological parameters of the femoral head-neck junction, including the α-angle and head-neck offset ratio (HNOR).

RESULTS

The α-angle and HNOR after collapse (58.3° ± 10.0° and 0.138 ± 0.033, respectively) indicated significantly decreased anterior femoral head-neck offset compared with those before collapse (46.2° ± 5.7° and 0.178 ± 0.018, respectively; p < 0.0001). These parameters had a positive association with the depth of femoral head collapse (p < 0.0001 and p < 0.01, respectively). However, there were no significant differences in either the α-angle or HNOR between hips with ONFH before collapse and hips without ONFH.

CONCLUSIONS

This study demonstrated that the decreased femoral head-neck offset observed in patients with ONFH was a consequence of collapse.

Effect of vascular endothelial growth factor 121 adenovirus transduction in rabbit model of femur head necrosis

BACKGROUND

Our objective was to observe the role of vascular endothelial growth factor (VEGF) 121 gene transfer in promoting vascular reconstruction and bone repair in femur head necrosis of rabbits.

METHODS

The femoral head necrosis model was induced by injection with ethanol. The necrotic femoral head was transfected with a human adenoviral vector expressing VEGF (Ad-hVEGF121). Bone formation in the subchondral necrotic region was analyzed using histology, by measuring the bone mineral density value, and by observing bone trabecular morphology using image analysis.

RESULTS

Revascularization level, bone formation rate, bone quality and quantity, and mineralization level in the subchondral necrotic region of the gene transfection group were significantly higher than the control groups. The control groups had more subchondral bone resorption compared with the gene transfection group.

CONCLUSION

VEGF might promote bone formation and revascularization in the subchondral necrotic region of the femoral head, indirectly protecting the necrotic bone trabecula from absorption and avoiding a reduction in the mechanical function of the subchondral region.

Avascular necrosis of the femoral head: vascular hypotheses

Vascular hypotheses provide compelling pathogenic mechanisms for the etiology of avascular necrosis of the femoral head (ANFH). A decrease in local blood flow of the femoral head has been postulated to be the cause of the disease. Several studies in human and animal models of ANFH have shown microvascular thrombosis. Endothelial cell damage could be followed by abnormal blood coagulation and thrombus formation with any resulting degeneration distal to the site of vascular occlusion. Other studies suggest that thrombophilia, particularly impaired fibrinolysis, plays a potential role in thrombus formation in ANFH. Reduction in shear stress due to decreased blood flow could lead to apoptosis of endothelial cells, which can ultimately contribute to plaque erosion and thrombus formation. Dysregulation of endothelial cell activating factors and stimulators of angiogenesis or repair processes could also affect the progression and outcome of ANFH. Likewise, regional endothelium dysfunction (RED), referred to as a potential defect in endothelial cells located in the feeding vessels of the femoral head itself, may also have a crucial role in the pathogenesis of ANFH. Molecular gene analysis of regional endothelial cells could also help to determine potential pathways important in the pathogenesis of ANFH.

Bone marrow edema of the forefoot after chevron osteotomy--a rare cause of metatarsalgia: a case report

Treatment options of bone marrow edema syndrome, which is associated with vascular disturbances, are protracted nonoperative treatment or core decompression which still demands several weeks until complete recovery. We obtained excellent results by the use of the vasoactive drug iloprost, a stable prostacyclin analogue, leading to a complete relief of symptoms in cases of bone marrow edema which had initially suggested early avascular necrosis of the second metatarsal head. The bone marrow edema of the second metatarsal bone was thought to be due to altered biomechanics following a distal first metatarsal chevron osteotomy. During the five days of iloprost infusion, the patient reported relief of rest pain. After therapy, the pedobarogram was normalized. The AOFAS forefoot score improved from 44 to 85 points after one month, and to 95 points after three months. At that time, the marrow showed normal signals. Without additional intervention the patient was able to resume normal activities.