Free Vascularized Fibular Graft Research Articles

Vascularized Fibular Grafts for Avascular Necrosis After Slipped Capital Femoral Epiphysis: Is Hip Preservation Possible?

Avascular necrosis (AVN) of the femoral head is a potential complication in patients with slipped capital femoral epiphysis (SCFE), radiographically occurring in 3-60%. This may lead to early hip fusion or hip arthroplasty. Free vascularized fibular grafting (FVFG) may provide a reasonable means to preserve the femoral head. We asked: (1) What percentage of patients with AVN after SCFE treated with FVFG underwent subsequent THA or hip fusion and what was the lifespan of the FVFG? (2) Did the graft survival rate of FVFG for AVN after SCFE coincide with historically reported rates of FVFG for idiopathic AVN? And (3) did hip function improve after FVFG? We retrospectively reviewed 52 patients who underwent FVFG for SCFE. We calculated the longevity of the graft and factors associated with graft survival. Harris hip scores (HHS) were recorded pre- and postoperatively. Minimum followup was 1 month (median, 19 months; range, 1-136 months). Five of the 52 patients (10%) underwent conversion to THA (four) or hip fusion (one). Mean age was greater in these patients than in those not requiring further procedures: 16 versus 13 years. Median graft survival time before arthroplasty/fusion was 12 years (range, 2-16 years) while it is currently 8 years (range, 2-16 years) in patients not undergoing subsequent procedures. HHSs improved 35 points on average (38 points preoperatively to 73 points postoperatively). In patients undergoing FVFG for AVN secondary to SCFE, 90% have maintained their native hips for 8 years with improved hip function, similar to other published reports of FVFG. Further followup is needed of patients currently retaining their FVFGs as to eventual conversion to THA or fusion. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The Effect of Postoperative Corticosteroid Administration on Free Vascularized Fibular Grafting for Treating Osteonecrosis of the Femoral Head

Free vascularized fibular grafting (FVFG) has been reported to be an effective method of treating osteonecrosis of the femoral head (ONFH). This study evaluated whether postoperative maintenance doses of corticosteroids had an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH. We retrospectively reviewed the records of 39 patients (67 hips) who had received maintenance doses of corticosteroids following FVFG. This group was matched to a group of patients who had not received corticosteroids treatment after operation. The mean follow-up duration was 5.4 years for the postoperative corticosteroid administration group (PCA group) and 5.0 years for the control group. At the latest follow-up, the average increase in Harris hip score was 11.1 ± 8.7 points for all hips in the PCA group and 12.6 ± 7.4 points for all hips in the control group (P > 0.05). In the PCA group, through radiographic evaluation, 49 hips were improved, 10 hips appeared unchanged, and 8 hips appeared worse. In the control group, 47 hips were improved, 13 hips appeared unchanged, and 7 hips appeared worse. The results suggested that postoperative maintenance doses of corticosteroids do not have an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH.

Reconstruction Using a Free Vascularized Fibular Graft after Frozen Autograft Reconstruction for Osteosarcoma of the Distal Tibia: A Case Report

Recently we have been performing biological reconstruction for malignant bone tumors of the extremities using frozen autografts. Here we present a case treated with free vascularized fibular graft (FVFG) after this method. A 23-year-old man developed osteosarcoma in his left distal tibia. There was nonunion after frozen autograft reconstruction, which we treated with FVFG. Twenty-four months later, bridging between the host bone and the frozen autograft was achieved. Our department has achieved bone union in almost all cases, but we sometimes encounter cases of nonunion after this method because of delayed blood supply. In these instances, reconstruction using FVFG may represent an attractive choice for salvage treatment.

Primena slobodnog vaskularizovanog fibularnog grafta-reznja u lecenju velikih kostanih defekata posle povrede ekstremiteta

Free vascularized fibular graft is of the greatest importance in the orthopaedics and trauma. Bone, skeletal defects due to the trauma, infections and congenital anomalies could be successfully solved by the free vascularized fibular grafts. In this article the main anatomical data of fibular graft, surgical techniques, indications for the FVFG in the treatment of trauma caused bone defects or its complications -sequels are described.

The Vascularized Fibular Graft in the Pediatric Upper Extremity: A Durable, Biological Solution to Large Oncologic Defects

Skeletal reconstruction after large tumor resection is challenging. The free vascularized fibular graft (FVFG) offers the potential for rapid autograft incorporation as well as growing physeal transfer in pediatric patients. We retrospectively reviewed eleven pediatric patients treated with FVFG reconstructions of the upper extremity after tumor resection. Eight male and three female patients were identified, including four who underwent epiphyseal transfer. All eleven patients retained a functional salvaged limb. Nonunion and graft fracture were the most common complications relating to graft site (27%). Peroneal nerve palsy occurred in 4/11 patients, all of whom received epiphyseal transfer. Patients receiving epiphyseal transplant had a mean annual growth of 1.7 cm/year. Mean graft hypertrophy index increased by more than 10% in all cases. Although a high complication rate may be anticipated, the free vascularized fibula may be used to reconstruct large skeletal defects in the pediatric upper extremity after oncologic resection. Transferring the vascularized physis is a viable option when longitudinal growth is desired.

Reconstruction of Proximal Humeral Defects with Shoulder Arthrodesis Using Free Vascularized Fibular Graft

Treatment of proximal humeral bone loss resulting from tumor resection or from infection following shoulder arthroplasty represents a reconstructive challenge. Shoulder arthrodesis is an appropriate salvage procedure but is associated with a high rate of complications. The purpose of this report is to describe the surgical technique and report the functional outcomes in a series of patients treated with shoulder arthrodesis using free vascularized fibular graft. Nine patients were included in this study. Two-stage reconstruction was performed in three patients with a methicillin-resistant Staphylococcus aureus infection following primary shoulder hemiarthroplasty. The remaining six patients had an aggressive or malignant tumor of the proximal aspect of the humerus, and tumor resection included the rotator cuff in all of these patients and the axillary nerve in three. All nine patients underwent shoulder arthrodesis using free vascularized fibular graft; eight patients had fixation with two plate-screw constructs, and one patient had fixation with only one plate and screws. Clinical and radiographic evaluation of all patients was performed at a mean of sixty months postoperatively. The Musculoskeletal Tumor Society (MSTS) function score and the Toronto Extremity Salvage Score (TESS) were used to assess overall function of the upper limb. Mean active shoulder abduction and flexion were both 80° (range, 60° to 100°). All but one patient could bring the hand to the mouth. The mean MSTS function and TESS values were twenty-four of thirty and 82%, respectively, representing a good functional outcome. Two of nine patients had a major complication. Union and fibular hypertrophy were achieved in seven of the nine patients. Shoulder arthrodesis using free vascularized fibular graft with double plate fixation is a reliable salvage procedure in patients with major proximal humeral bone loss.

The Vascularized Fibular Graft in Precollapse Osteonecrosis: Is Long-term Hip Preservation Possible?

Osteonecrosis of the femoral head (ONFH) is a debilitating condition affecting primarily young patients. Free vascularized fibular grafting (FVFG) may provide a durable means to preserve the femoral head. When used in the precollapse stages of ONFH, this treatment may alter the course of disease. We asked: (1) In what percentage of patients does FVFG preserve the femoral head beyond 10years? (2) When long-term preservation is not achieved, what is the duration of femoral head preservation? (3) Do demographic or etiologic factors predict FVFG survivorship? (4) What long-term improvements in function and activity can be anticipated? We retrospectively reviewed 61 patients (65 hips) who underwent FVFG for precollapse ONFH. We calculated graft survivorship, SF-12 scores, activity levels, and Harris hip scores. Minimum followup was 10.5years (mean, 14.4years; range, 10.5-26years). Results Forty-nine of 65 hips (75%) had surviving FVFG for at least 10years. At last followup, 39 of 65 hips (60%) had surviving FVFG, with a mean graft survival time of 15years (range, 10.5-26.1years). Twenty-six of the 65 hips with FVFG (40%) underwent conversion to THA at a mean of 8years postoperatively. Demographic factors, lesion size, additional procedures, and low preoperative function were not associated with changes in graft survivorship. Pain and function were similar in patients with surviving FVFG and patients who had conversion to THA. Patients with surviving FVFG were more likely to engage in impact sports or active events than were patients who had conversion to THA. When patients with precollapse ONFH undergo FVFG, the majority have preservation of the hip lasting for greater than 10years with low levels of pain and reasonable function. In patients who ultimately undergo conversion surgery to THA, the mean duration of hip preservation before conversion is 8years. We continue to use FVFG for treating patients younger than 50years with symptomatic, precollapse ONFH. Level IV, therapeutic study. See Instructions to Authors for a complete description of levels of evidence.

Functional results of reconstructive hip arthrodesis for periacetabular malignant tumor

Background We followed up four patients receiving reconstructive hip arthrodesis with a free-vascularized fibular graft (FVFG) for malignant bone tumor in order to restore lower limb function after wide resection of the periacetabular bone tumor.

Folded free vascularized fibular grafts for the treatment of subtrochanteric fractures complicated with segmental bone defects

Subtrochanteric fractures of the femur complicated with segmental bone defects are uncommon injuries and challenging to manage. We evaluated the effect of reconstructing extensive bone defect in the subtrochanteric area (mean, 6.9 cm) with folded free vascularized fibular graft (FVFG). Between 2001 and 2007, 14 cases of subtrochanteric fractures complicated with huge bone defects treated by folded FVFG transfer in our hospital were retrospectively reviewed. The defect was reconstructed by folded FVFG transfer and locking plate stabilization in 10 patients with no sign of infection at admission (group 1). In the other four patients presented with infections (group 2), the defect was reconstructed by folded FVFG transfer and external fixator fixation. The average follow-up period was 67.4 months. Bone union was achieved in all of the cases at an average of 5.4 months (range, 4-6 months). Primarily, bone union was achieved in all of the cases in group 1, but one stress fracture occurred in group 2. The full weight bearing time was 5.4 months (range, 5-6 months) in group 1 and 8.5 months (range, 8-9 months) in group 2. Seven patients in group 1 had the locking plate removed in an average of 27 months (range, 18-38 months). In group 2, the external fixator removal time was 13 months (range, 10-18 months). There was no varus deformity at the final follow-up in group 1. The neck-shaft angle measured during the postoperative period and at final follow-up was 129.6 degrees and 129.4 degrees, respectively. In group 2, the neck-shaft angle at the final follow-up was significantly less than the angle measured at the postoperative period (115.5 vs. 129.5 degree, p = 0.021). The range of motion of the hip and knee joint (extend and flex) was 100 degrees or more in all patients at the final follow-up. The results of this study showed that huge subtrochanteric bone defects reconstructed by folded FVFG and locking plate were highly successful in achieving bone union, reducing risks of postoperative stress fracture and preventing malunion. When huge bone defects in the subtrochanteric area complicated with acute or chronic infections, the technique of external fixator offers an alternative to reconstruct the stability of the proximal femur after folded FVFG. However, because of the inadequate stabilization, the risks of varus malunion and postoperative stress fracture could be increased after external fixator fixation. V, therapeutic study.

Massive juxta-articular defects of the distal femur reconstructed by series connected double-strut free-vascularized fibular grafts

We evaluate the clinical results of reconstructing massive juxta-articular defects of the distal femur (mean, 16.4 cm) with series-connected double-strut free-vascularized fibular grafting (FVFG) and external fixator fixation. We retrospectively reviewed a consecutive series of 19 patients, who underwent FVFG transfer because of massive juxta-articular defects of distal femur. Sixteen cases had complete records and included in this study. Five patients underwent double-strut FVFGand 11 patients underwent series-connected double-strut FVFG. FVFG was performed from 2 months to 3 months after the clinica lsigns of the infection had subsided and erythrocyte sedimentation rates had returned to normal. Both fibulas (mean, 18.6 cm) were harvested to reconstruct the femoral defect, half-ring sulcated external fixator (Orthofix Srl, Italy), and K-wires were used to provide stabilization. Five fibular grafts (15.6%) had vascular complications on flap monitoring. Fifteen of the sixteen reconstructed femurs (93.8%)united primarily. Stress fracture occurred in one patient. The mean duration to achieve union was 7.1 month (range, 4–18 months).Full weight-bearing walking was allowed 3 months after the confirmation of bone union (mean, 10 months; range, 7–22 months).The external fixator was removed 12.2 months (range, 10–16 months) postoperatively. The K-wires were removed 26.4 months(range, 23–30 months) postoperatively. There was no statistically significant difference of hypertrophic change between series-connected grafts and conventional double-strut grafts (27.18 vs. 24.43%, p = 0.186) and also between the three levels of the grafted fibula. Within the series-connected group, the difference of hypertrophic change between anterograde fibular grafts and retrograde fibular grafts was also not significant (25.24 vs. 29.12%, p = 0.178). The overall rate of knee stiffness (90 degree)was as high as 68.75% (11 of 16 patients). Massive juxta-articular defects of the distal femur are difficult and uncommon injuries. The results of this study indicate that the huge femoral defect reconstructed by series-connected double-strut FVFG provide good results in achieving bone union, reducing stress fracture rate, and achieving leg length equality.

Free Vascularized Fibula Graft to Treat Chondroblastoma of the Hip

Chondroblastomas are rare tumors that present in the epiphysis of the long bones. Bone grafting following aggressive surgical curettage has yielded the best results. When present in the femoral head, they pose a higher risk of recurrence due to the difficulty of achieving an adequate resection without destroying the structural integrity of the weight-bearing surface. This article describes a case of surgical treatment of a chondroblastoma of the femoral head with the use of a free vascularized fibula graft. A 26-year-old woman had several months of increasing left hip pain and decreased range of motion. Imaging studies confirmed a large bubbly lesion with sclerotic borders in the left femoral head consistent with chondroblastoma. After performing an aggressive and complete excisional biopsy, a large cavitary defect remained in the femoral head. Reconstruction of the defect and structural support was achieved using a free vascularized fibula. Nine years postoperatively, the patient had full hip motion, no pain, and no radiographic evidence of collapse. A free vascularized fibula graft is an excellent option for the reconstruction of a large femoral head defect after chondroblastoma resection.

Free vascularized fibular grafts in Type 3 open tibia fractures

The aim of this study was to evaluate the results and complications of free vascularized fibular grafting (FVFG) for the reconstruction of bone defects in Gustilo Type 3 open tibia fractures. Free vascularized fibular grafting was performed on open tibia fractures with a bone defect of an average of 10 (range: 6 to 18) cm in 21 patients (19 males, 2 females; mean age: 32 years; range: 16 to 47 years). Primary FVFG was performed for 15 patients with open fractures and secondary FVFG in 6 patients with osteomyelitis due to open fractures or defective nonunions. Bony unions were evaluated retrospectively. At a mean follow-up time of 74 (range: 18 to 216) months, 18 patients were examined for malalignment, shortness, and range of motion. Quality of life was evaluated using the Short Form 36 (SF-36). Mean bony union times for the proximal and distal fibula were 19 (range: 16 to 24) weeks and 20 (range: 16 to 28) weeks, respectively. Proximal nonunion was detected in three patients. Mean external fixation removal time was 6.3 (range: 3 to 14) months. Stress fractures occurred in 15 patients following fixator removal. Malalignment of over 5 degrees was detected in 7 patients and shortness over 2 cm was detected in 4 patients. SF-36 scores were significantly lower in the domains of physical functioning, role limitation due to physical problems, bodily pain, general perception of health, social function, and role limitation due to emotional problems. Mental health, energy and vitality were similar to the healthy reference group. Free vascularized fibular grafting appears to be a reliable and effective method for reconstructing bone defects and soft tissue defects in a single session in open tibia fractures.

Osteonecrosis in Systemic Lupus Erythematosus: An Early, Frequent, and Not Always Symptomatic Complication

Osteonecrosis may complicate the course of systemic lupus erythematosus and may contemporaneously affect multiple joints. The major risk factor associated with the development of osteonecrosis is the use of glucocorticoid at high doses. Recent studies using serial MRI, which represents the “gold standard” for the early detection of osteonecrosis, yielded some interesting findings about the natural history of this clinical entity. Osteonecrosis in the majority of the cases is asymptomatic and occurs early in the course of the disease. Its later occurrence is associated with lupus flare that requires the increase of corticosteroid dose. The optimal treatment of osteonecrosis is controversial. In case of silent osteonecrosis involving a small area conservative strategy is usually adequate. When lesions are symptomatic surgical treatment as core decompression or free vascularized fibular grafting is required; extracorporeal shockwave treatment may represent an alternative therapeutic approach. When the lesion has a medium-large dimension or involves a weight-bearing area bone collapse is a common complication requiring total joint replacement. Coadministration of bisphosphonate or warfarin with high doses of corticosteroid might be a promising preventive strategy of osteonecrosis.

Free Vascularized Fibula Grafts after Wide Resection of Sarcoma of Long Bones

Free Vascularized Fibula Grafts after Wide Resection of Sarcoma of Long Bones

Pain relief following osteonecrosis of the femoral head treated by free vascularized fibular grafting.

Pain is the core and basic problem in the treatment of osteonecrosis of the femoral head (ONFH). However, it is unclear about the status of pain relief following ONFH treated by free vascularized fibular grafting (FVFG) and the level of pain relief contributed to clinical results. Therefore, we designed a consecutive and prospective study to investigate post-operative pain relief in the treatment of osteonecrosis of the femoral head by FVFG. One hundred and fifty-one patients with unilateral osteonecrosis of the femoral head were enrolled consecutively for current prospective study from January to August of 2006. Patients were managed by modified technique of free vascularized fibular grafting. Pre-operative, post-operative Harris hip score (HHS) and Harris pain score (HPS) were recorded and compared statistically, meanwhile, correlation between disease severity and Harris hip score, Harris pain score were revealed. All patients had an average follow-up of 54.3months. Post-operative Harris hip score could be improved from 73.7 to 83.5 averagely in stage-II patients, 64.6 to 78.9 in stage-III, and 53.6 to 72.4 in stage-IV. As for Harris pain score, it was elevated from 28.8 to 38.6 in stage-II patients, 25.5 to 36.6 in stage-III, and 21.8 to 34.2 in stage-IV. Taken together, HHS was improved from 67.7 to 80.3 (ΔHHS=12.6), and HPS was improved from 26.6 to 37.3 (ΔHPS=10.7) averagely. Harris pain score could be employed to monitor prognosis of osteonecrosis of the femoral head treated by free vascularized fibular grafting. Improvement of HPS was the heaviest contributor to elevation of HHS, and both of them conceived of a close relationship with disease severity.

Split Tibia Vascularized Fibular Graft for Congenital Pseudarthrosis of the Tibia

Free vascularized fibular graft (FVFG) has been recognized as a curative surgical treatment for congenital pseudarthrosis of the tibia (CPT). However, bone union is not always obtained in some patients, and refracture often occurs in others even after union is achieved. To avoid such complications, we have designed a new split-tibia coaptation technique (STCT) for FVFG. We performed FVFG using STCT in 2 patients with CPT. Both the proximal and distal stumps of the tibia were split longitudinally into 2 with minimum tibial resection, and then a fibular graft was placed into the formed gutters and stabilized by external fixation. Successful bone union was achieved at postoperative weeks 13 and 12, respectively. The diameter of each fibular graft was enlarged to 107% and 83% of the contralateral tibia, and refracture did not occur during the follow-up periods of almost 7 and 4 years. Both the patients could walk without any limitations. This novel coaptation technique for FVFG provides early bone union, enlargement of graft diameter, and prevention against refracture in patients with CPT.

Transfer of Ipsilateral Fibula on Vascular Pedicle for Treatment of Congenital Pseudarthrosis of the Tibia

Although the use of free vascularized fibula grafts has frequently been reported in the treatment of congenital pseudarthrosis of the tibia, the use of ipsilateral fibula graft on a vascular pedicle is uncommon. We reviewed the long-term results of this procedure in 11 patients. The records of 11 patients who underwent transfer of the ipsilateral fibula on a vascular pedicle between 2.1 and 10.8 years of age were retrospectively reviewed. Average follow-up was 11 years after the index procedure. Seven patients had reached skeletal maturity. Clinical records and radiographs were reviewed to determine patient demographics, surgical parameters, union rate, refracture rate, residual deformity, and functional outcome. Eight patients (73%) achieved union at an average of 20.1 months. Additional bone grafting procedures were required in 4 patients with distal nonunions. There were 3 refractures (38%). Four patients eventually underwent amputation, and 1 patient had a persistent nonunion at final follow-up. Residual deformity included tibial valgus and procurvatum deformities, limb length discrepancy, and ankle valgus. Use of the ipsilateral fibula did not seem to increase the risk of ankle valgus. Functional outcomes were good in all but one patient. Use of the ipsilateral fibula as a pedicle graft provides reasonable results in healing congenital pseudarthrosis of the tibia. Patients should be monitored for the sequelae of this condition, including nonunion, refracture, shortening, and angular deformity, and treated accordingly. Therapeutic Level IV.

Femoral head osteonecrosis: Why choose free vascularized fibula grafting

Osteonecrosis of the femoral head is a disease in which bone death occurs and usually progresses to articular incongruity and subsequent osteoarthritis. To delay the process of the disease and the conversion to total hip arthroplasty, many surgical techniques have been described. Core decompression, nonvascularized autologous bone grafts, porous tantalum implant procedure, and various osteotomies have been used for the management of early precollapse stage osteonecrosis of the femoral head. However, none of these procedures is neither entirely effective nor can obtain predictable results. With the progress of microsurgery, the implantation of a free vascularized fibula graft to the necrotic femoral head has provided the most consistently successful results. Although the procedure is technically demanding, there is growing recognition that the use of free vascularized fibula graft may improve patient quality of life by functional improvement and pain alleviation. The success of the procedure is related to decompression of the femoral head, excision of the necrotic bone, and addition of cancellous bone graft with osteoinductive and osteoconductive properties, which augments revascularization and neoosteogenesis of the femoral head. Free vascularized fibula graft, especially in younger patients, is a salvaging procedure of the necrotic femoral head in early precollapse stages. In postcollapse osteonecrosis, the procedure appears to delay the need for total hip arthroplasty in the majority of patients. The purpose of this review article is to update knowledge about treatment strategies in femoral head osteonecrosis and to compare free vascularized fibula grafting to traditional and new treatment modalities.

Fixation and reconstruction of severe tibial shaft fractures with vascularized fibular grafting

Based on the considerable experience for management of combined bone and composite soft-tissue defects in the limbs by free vascularized fibula or osteocutaneous fibular flap grafting, the authors present the effective alternative for management of the severe comminuted tibial shaft fractures in one-stage reconstructive technique. Twenty-six patients were male and 12 were female, and their mean age was 32 years (range 15-57 years). Ten tibial shaft fractures were closed and 28 were open. Based on the AO classification, there were 12 group C1 fractures and 24 group C3 fractures according to the fracture pattern and degree of comminution. With the exception of eight cases that were delayed for 3-5 days for primary treatment in another hospital, 30 cases were treated on an emergency basis within an average of 12 h since the initial injury (range 6-22). Normal healing occurred in 31 fractures with a mean healing time of 21 weeks (range 18-24 weeks). Delayed union in 7 with a mean of 32 weeks (range 28-41 weeks), and there were no nonunion and infections. The vascularized fibula allows for fast bone fusion. In this context, the grafted fibula segment appeared to be a valuable reconstructive tool that offered good fracture stabilization and vascularised bone graft. The attached fibular flap can also provide a large piece of mobile skin to cover the soft-tissue defect in grade III open-tibial fractures. It demonstrates that this early free vascularized fibula graft is a useful and effective option for treating the severe comminuted tibial shaft fractures.

Modified Free Vascularized Fibular Grafting for the Treatment of Femoral Neck Nonunion

To evaluate a modified free vascularized fibular grafting procedure with an anterior approach to the hip as a treatment for femoral neck nonunions. Retrospective radiographic and clinical review. Level I trauma center. Twenty-six femoral neck nonunions treated between November 2000 and December 2005. Harris Hip scoring system and radiographic standard evaluation for bone union. The average follow-up period was 29.3 months (range, 12-63 months). The average duration of the surgery was 2.5 hours (range, 2-4 hours). Average blood loss was 300 mL (range, 200-400 mL). The neck-shaft angle was improved by 2.3 degrees on average. Twenty-four of 26 femoral neck nonunions healed without any severe complications. Average union time was 5.3 months (range, 3-9 months). Twenty-four patients had well-functioning hips with an average Harris hip score of 87.9 as compared with the average preoperative Harris hip score of 57.8. One case developed osteonecrosis of the femoral head requiring total hip arthroplasty 2 years after the index procedure. One case developed an immediate postoperative infection. The clinical result indicates that the anterior approach modification of free vascularized fibular grafting is a valuable procedure in the treatment of femoral neck nonunions.