Summary Statement.
Collapse of femoral head associated with end-stage arthritis form hallmark of osteonecrosis of femoral head. Purpose was to assess efficacy of platelet rich plasma following core decompression in early stage of osteonecrosis of femoral head. Forty consecutive age, sex and BMI-matched patients of osteonecrosis were enrolled for this prospective randomized comparative double blinded clinical study. 19 patients belonged to intervention group (PRP with Core decompression) and 21 to control (Core decompression) group. 8ml of autologous PRP was injected into channels alongwith Calcium Chloride (4:1) after core decompression. Patients were assessed for outcome measures by pain score, functional and Harris Hip scores, Modified Kerboul angle (combined necrotic angle) in MRI. Patients were followed up after 6, 24 weeks and final follow up (mean 10.33 months).Introduction
Methods
Patients with osteonecrosis of the femoral head are typically younger, more active, and often require high rates of revision following primary total hip arthroplasty. However, outcomes of revision hip arthroplasty in this patient population have been rarely reported in the literature. The purpose of this study was to report the intermediate-term clinical and radiographic outcomes of revision hip arthroplasty in patients with osteonecrosis of the femoral head. Between November 1994 and December 2009, 187 revision hip arthoplasty were performed in 137 patients who had a diagnosis of osteonecrosis of the femoral head. Exclusion criteria included infection, recurrent instability, isolated polyethylene liner exchange, and inadequate follow-up (less than 3 years). The final study cohort of this retrospective review consisted of 72 patients (75 hips) with a mean age of 53.3 years (range, 34 to 76). Components used for the acetabular revision included a cementless porous-coated cup in 58 hips and an acetabular cage in 2 hips. Components used for the femoral revision included a fully grit-blasted tapered stem in 30 hips and a proximally porous-coated modular stem in 9 hips. The mean duration of follow-up was 7 years (range, 3 to 17).Introduction
Materials & Methods
The natural history of osteonecrosis of the femoral head (ONFH) is not cleanly understood, but most of them progresse to the joint destruction and requires total hip replacement arthroplasty. There are several head preserving procedure, but no single therapeutic method proved to be effective in preventing progression of the disease. The possibility has been raised that implantation of bone marrow containing osteogenic precursors may be effective in the treatment of this disease. However, there are no long-term follow-up results of cell therapy for ONFH. AS far as we know, there are no reports about bone graft and cell therapy for ONFH. Therefore, we performed a prospective clinical and radiological evaluation on ONFH treated with core decompression combined with autoiliac bone graft and an implantation of autologous bone marrow cells as a therapeutic method of ONFH. Sixty-one hips in 52 patients with ONFH were included in this study. The average follow-up of the patients was 68 (60∼88) months. The necrotic lesions were classified according to their size and location, and we compared the results.Introduction
Materials and Methods
The pathophysiology of osteonecrosis of femoral head (ONFH) is uncertain for most cases with speculation of vascular impairment and changes in cell biology due to multi-factorial etiologies including corticosteroid, alcohol, smoking, trauma, radiation or caisson disease and genetic. Extracorporeal shockwave therapy (ESWT) began with an incidental observation of osteoblastic response pattern during animal studies in the mid-1980 that generated an interest in the application of ESWT to musculoskeletal disorders. The mechanism of shockwave therapy is not fully understood but several reports showed better clinical outcomes and promoted bone remodelling and regeneration effect of the femoral head after ESWT in ONFH. Therefore, we compared the clinical results of the use of extracorporeal shock wave therapy (ESWT) on the patients with ONFH in radiographic staging. We evaluated 24 patients with 32 hip joints diagnosed ONFH treated with ESWT from 1993 to 2012. Average follow-up period was 27 months, and patients were average 47.8 aged. Association Research Circulation Osseous (ARCO) staging system was used to grade radiographic stage before treatment. All the patients were divided to two groups; group 1 (ARCO stage I,II), group 2 (ARCO stage III). Comparative analysis was done between two groups with visual analogue scale (VAS) score and Harris hip score (HHS) at pre-treatment, 3, 6, 12 and 24 months after treatments. The failure was defined when radiographic stage was progressed or arthroplasty surgery was needed due to clinical exacerbation.Introduction
Methods
Introduction and Objective.
The use of bisphosphonates in the treatment of
We performed 96 Birmingham resurfacing arthroplasties of the hip in 71 consecutive patients with
The purpose of this study was to analyze the long-term effect of arterial perfusion of drugs and bone marrow stromal cells (bMSCs) on osteonecrosis of femoral head (ONFH). From Jan 1997 to Mar 2004, one hundred and seventeen patients with ONFH were consecutively enrolled to receive a digital subtraction angiography (DSA) in arteriae circumflexa femoris medialis and arteriae circumflexa femoris lateralis. In DSA, a dosage of drugs (urokinase, salvia injection, and tetramethylpyrazine) and autologous bMSCs or only the drugs were perfused into the arteries. The morphological changes of the arteries in DSA after perfusion were recorded. Symptoms radiographs, and the Harris hip-rating score were determined preoperatively and at each follow-up examination at one month, six months, one year, 2 years and 5 years after the treatment. 83 patients were followed up for more than five years. The median follow-up period was 7.9 years. After the drugs had been perfuse, the arteries became thicker, and more than 2 branches appeared in DSA. Five years after the operation, the Harris hip score of 32 patients (38 hips) treated by arterial perfusion of simplex drugs (group A) increased from 59.24±5.28 to 71.80±6.37 (p<
0.01), and the excellent and good rate of centesimal evaluation was 57.9%. The Harris hip score of 51 patients (59 hips) treated by arterial perfusion of drugs and autologous bMSCs (group B) increased from 59.52±4.85 to 78.29±6.05 (p<
0.01), and the excellent and good rate was 78.0% which was significantly higher than that of group A (p=0.035). Since two years after operation, the Harris hip score of group A was significantly higher than that of group B (p<
0.01). Among the patients in group B, the rate of excellent and good in early stages (˜,˜ a and ˜ b according to Ficat classifying, 50 hips) was 84.0%, which was better than the rate in the terminal stage (Ficat III, 9 hips, the excellent and good rate was 44.4%)(p = 0.028), and the rate of excellent and good in low age group (<
40 years, 33 hips) was also better than that in high age group (≥ 40 years, 26 hips)(p=0.038). We conclude that arterial perfusion of drugs and autologous bMSCs treating osteonecrosis of femoral head is safe and effective. The long-term therapeutic effect is more satisfactory than that of simplex arterial perfusion of drugs.
Of 24 intertrochanteric osteotomies for
Haemophilia is a rare cause of
The pathophysiological basis of alterations in trabecular bone of patients with osteonecrosis of the femoral head (ONFH) remains unclear. ONFH has classically been considered a vascular disease with secondary changes in the subchondral bone. However, there is increasing evidence suggesting that ONFH could be a bone disease, since alterations in the functionality of bone tissue distant from the necrotic lesion have been observed. We comparatively studied the transcriptomic profile of trabecular bone obtained from the intertrochanteric region of patients with ONFH without an obvious aetiological factor, and patients with osteoarthritis (OA) undergoing total hip replacement in our Institution. To explore the biological processes that could be affected by ONFH, we compared the transcriptomic profile of trabecular bone from the intertrochanteric region and the femoral head of patients affected by this condition. Differential gene expression was studied using an Affymetrix microarray platform. Transcriptome analysis showed a differential signature in trabecular bone from the intertrochanteric region between patients with ONFH and those with OA. The gene ontology analyses of the genes overexpressed in bone tissue of patients with ONFH revealed a range of enriched biological processes related to cell adhesion and migration and angiogenesis. In contrast, most downregulated transcripts were involved in cell division. Trabecular bone in the intertrochanteric region and in the femoral head also exhibited a differential expression profile. Among the genes differentially expressed, we highlighted those related with cytokine production and immune response. This study identified a set of differently expressed genes in trabecular bone of patients with idiopathic ONFH, which might underlie the pathophysiology of this condition.
We studied the natural history of nontraumatic
We reviewed 41 hips in 40 patients at three to 11 years (average 6.3 years) after Sugioka transtrochanteric rotational osteotomy for non-traumatic
Introduction. Although osteonecrosis of the femoral head has been observed in young adult patients with autoimmune diseases such as SLE and MCTD that are treated by corticosteroids, the pathogenesis of the osteonecrosis remains unclear. We established a rat model with osteonecrosis of the femoral head by injecting lipopolysaccharide (LPS) and corticosteroid, and assessed consequences of the histopathological alteration of the femoral head, the systemic immune response, and the lipid synthesis. Methods. Male Wistar rats were given 2 mg/kg LPS intravenously on days 0 and 1 and intramuscularly 20 mg/kg methylprednisolone on days 2, 3, and 4. The animals were sacrificed 1, 2, 3, or 4 weeks after the last injection of the methylprednisolone. Histopathological and biochemical analyses were performed every week. The bone samples were then processed for routine hematoxylin and eosin staining to assess the general architecture and injury of the tissue. The triglyceride and the total cholesterol concentrations in the PRP were measured. The levels of various cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ, TNF-α) in blood samples were measured. Results. The body weight of the rats over time decreased for 2 weeks but had recovered by week 4. The plasma triglyceride concentrations had decreased significantly by weeks 2 and 3. The total plasma cholesterol concentrations had increased significantly by week 1 but then decreased significantly by week 4. The plasma concentrations of IL-1?α, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-γ and TNF-α had increased significantly by week 1. These cytokines can all be induced by toll-like receptor 4 (TLR4) signaling. We defined osteonecrosis as the diffuse presence of empty lacunae or pyknotic nuclei of osteocytes in the bone trabeculae, accompanied by surrounding bone marrow cell necrosis.
Introduction.
Introduction:
The clinical and pathological findings in a case of early
Total hip arthroplasty (THA) outcome in patients with osteonecrosis of the femoral head ONFH) are excellent, however, there is controversy when compared with those in patients with osteoarthritis (OA). Reduced mineralization capacity of osteoblasts of the proximal femur in patients with ONFH could affect implant fixation. We asked if THA fixation in patients with ONFH is worse than in those with OA. We carried out a prospective comparative case (OA)-control (ONFH) study of patients undergoing THA at our hospital between 2017 and 2019. The minimum follow-up was 2 years. Inclusion criteria were patients with uncemented THA, younger than 70 years old, a Dorr femoral type C and idiopathic ONFH. We compared the clinical (Merlé D'Aubigné-Postel score) and radiological results related with implant positioning and fixation. Engh criteria and subsidence were assessed at the immediate postoperative, 12 weeks, 6 months, 12 months and yearly. Osteoblastic activity was determined by mineralization assay on primary cultures of osteoblasts isolated from trabecular bone samples collected from the intertrochanteric area obtained during surgery. Group 1 (ONFH) included 18 patients and group 2 (OA), 22. Average age was 55.9 years old in group 1 and 61.3 in group 2. (p=0.08). There were no differences related with sex, Dorr femoral type or femoral filling. The mean clinical outcome score was 17.1 in group 1 and 16.5 in group 2 (p=0.03). There were no cases of dislocation, infection, or revision surgery in this series. There were 5 cases (28%) of femoral stem subsidence greater than 3mm within 6 first months in group 1 and 1 case (4.5%) in group 2 (p=0.05). Although there were no significant differences related to clinical results, bone fixation was slower, and a greater subsidence was observed in patients with ONFH. Greater femoral stem subsidence was associated with a lower capacity for mineral nodule formation in cultured osteoblasts. The surgical technique could influence THA outcome in patients with reduced mineralization capacity of osteoblasts.
Surgical treatment for osteonecrosis of the femoral head (ONFH) includes both joint-preserving techniques and joint replacement. Joint preservation is more effective in early-stage ONFH; thus, prompt diagnosis when the femoral head is still salvageable is an important clinical goal. We report a 20-year retrospective study that summarizes the proportion of patients diagnosed with early-stage versus late-stage ONFH at initial presentation to our practice. Our institutional database was reviewed to identify patients 18–65 years of age who were diagnosed with atraumatic ONFH in our clinic between 1998–2018. The Association Research Circulation Osseous (ARCO) system was used to stage ONFH, based on available imaging. Patients with prior surgical treatment for ONFH were excluded.Background
Methods
Introduction:
Of 899 patients with sickle-cell disease, aged between 6 and 28 years, who attended clinics in the Guinea Savannah of Nigeria in 1982 and 1983, 29 had symptoms of
Symptomatic hip osteonecrosis is a disabling
condition with a poorly understood aetiology and pathogenesis. Numerous
treatment options for hip osteonecrosis are described, which include
non-operative management and joint preserving procedures, as well
as total hip replacement (THR). Non-operative or joint preserving
treatment may improve outcomes when an early diagnosis is made before
the lesion has become too large or there is radiographic evidence
of femoral head collapse. The presence of a crescent sign, femoral
head flattening, and acetabular involvement indicate a more advanced-stage
disease in which joint preserving options are less effective than
THR. Since many patients present after disease progression, primary
THR is often the only reliable treatment option available. Prior
to the 1990s, outcomes of THR for osteonecrosis were poor. However,
according to recent reports and systemic reviews, it is encouraging
that with the introduction of newer ceramic and/or highly cross-linked
polyethylene bearings as well as highly-porous fixation interfaces,
THR appears to be a reliable option in the management of end-stage
arthritis following hip osteonecrosis in this historically difficult
to treat patient population. Cite this article:
Introduction.
A staging system has been developed to revise the 1994 ARCO classification for ONFH. The final consensus resulted in the following 4-staged system: stage I—X-ray is normal, but either magnetic resonance imaging or bone scan is positive; stage II—X-ray is abnormal (subtle signs of osteosclerosis, focal osteoporosis, or cystic change in the femoral head) but without any evidence of subchondral fracture, fracture in the necrotic portion, or flattening of the femoral head; stage III—fracture in the subchondral or necrotic zone as seen on X-ray or computed tomography scans. This stage is further divided into stage IIIA (early, femoral head depression ≤2 mm) and stage IIIB (late, femoral head depression >2 mm); and stage IV—X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes, and/or joint destruction. Radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans may all be involved in diagnosing ONFH; however, the optimal diagnostic modality remains unclear. The purpose of this study was to identify: 1) how ONFH is diagnosed at a single academic medical center, and 2) if CT is a necessary modality for diagnosing/staging OFNH. The EMR was queried for the diagnosis of ONFH between 1/1/2008–12/31/2018 at a single academic medical center. CT and MRI scans were reviewed by the senior author and other contributors. The timing and staging quality of the diagnosis of ONFH were compared between MRI and CT to determine if CT was a necessary component of the ONFH work-up.Introduction
Methods
We have reviewed 54 hips in 46 patients from 2 to 14 years after a joint-preserving operation for idiopathic
Twenty-nine patients with
Introduction:
We have studied core biopsy specimens from 16 femoral heads affected by idiopathic avascular necrosis at the silent stage, when there were no clinical or radiographic manifestations but scintigraphy was positive. All the specimens showed necrosis of trabeculae and of bone marrow, but the most common and characteristic feature was evidence of old and new haemorrhage in the marrow. In the areas of intramedullary haemorrhages, trabeculae and bone marrow were completely necrotic, with a transitional area of incomplete necrosis between these areas and those without haemorrhagic lesions, where the trabeculae and bone marrow were normal. There was good correlation between necrosis and haemorrhagic episodes, and it was concluded that repeated intramedullary haemorrhage at the silent stage is probably related to the pathogenesis of idiopathic
The purpose of this study was to analyze trends in the surgical management of ON in recent years. Specifically, we evaluated the annual prevalences of: 1) joint preserving procedures (osteotomies and core decompression/grafts) and 2) joint non-preserving procedures (total hip arthroplasties [THAs], revision THAs, partial THAs) for the treatment of osteonecrosis of the femoral head (ONFH) between 2009 and 2016. A total of 406,239 ONFH patients who were treated between 2009 and 2016 were identified from a nationwide database. Treatment procedures were extracted using ICD-9-CM and ICD-10-CM procedure codes. Annual rates of each of the above procedures were calculated and the trends in the procedure types were also evaluated. Chi-square tests were performed to compare the annual prevalence of each procedure. The mean annual prevalence over the 8-year study period was calculated for each procedure.Introduction
Background
The purpose of this study was to compare the clinical and radiological findings in patients with
There is a high risk of the development of avascular
necrosis of the femoral head and nonunion after the treatment of
displaced subcapital fractures of the femoral neck in patients aged
<
50 years. We retrospectively analysed the results following
fixation with two cannulated compression screws and a vascularised
iliac bone graft. We treated 18 women and 16 men with a mean age
of 38.5 years (20 to 50) whose treatment included the use of an
iliac bone graft based on the ascending branch of lateral femoral
circumflex artery. There were 20 Garden grade III and 14 grade IV
fractures. Clinical and radiological outcomes were evaluated. The
mean follow-up was 5.4 years (2 to 10). In 30 hips (88%) union was
achieved at a mean of 4.4 months (4 to 6). Nonunion occurred in
four hips (12%) and these patients had a mean age of 46.5 years
(42 to 50) and underwent revision to a hip replacement six months
after operation. The time to union was dependent on age with younger
patients achieving earlier union (p <
0.001). According to the
Harris hip score which was available for 27 of the 30 hips with
satisfactory union, excellent results were obtained in 15 (score ≥ 90
points), fair in ten (score 80 to 90 points), and poor in two hips
(≤ 80 points). One patient aged 48 years developed avascular necrosis
of femoral head six years after operation and underwent total hip
replacement. The management of displaced subcapital fractures of the femoral
neck, in patients aged <
50 years, with two cannulated compression
screws and an iliac bone graft based on the ascending branch of
lateral femoral circumflex artery, gives satisfactory results with
a low rate of complication including avascular necrosis and nonunion. Cite this article:
Purpose: The purpose of this retrospective study was to assess clinical and radiological outcome at ten years follow-up at least in a continuous series of total hip arthroplasties performed in patients with
Without intervention 80% of hips with osteonecrosis (ON) will progress. Core decompression has shown favorable results (60–80% survivorship) in early stage ON, and recently, bone marrow aspirate concentration (BMAC) injection into the decompressed femoral head has been proposed to stimulate healing of the necrotic lesion and improve outcomes and survivorship. We retrospectively reviewed the clinical and radiographic outcomes of 42 hips in 26 patients who underwent core decompression with BMAC for ON with a minimum of 1 year follow up. We evaluated pre-op visual analog pain scores (VAS), Steinberg class based on radiographs, as well as Kerboul angle as measured on MRI. Clinical outcomes were reported as change in VAS at final follow up, advancement in Steinberg classification based on radiographs at final follow up, or decision to proceed with THA.Introduction
Methods
Introduction:
Post-traumatic osteonecrosis of the femoral head (ONFH) is a major complication of femoral neck fractures that require numerous solutions. The purpose of the current study is to investigate the effects of platelet-rich plasma (PRP) incorporated autologous granular bones graft for the treatment of pre-collapse stages (ARCO stage II-III) of post-traumatic ONFH. A total of 46 patients were eligible and enrolled into the study. 24 patients were treated with core decompression and PRP incorporated autologous granular bones graft (treatment group: 9 females and 15 males, age range, 16–39 years), and 22 patients with core decompression and autologous granular bones graft (control group: 6 females and 16 males, age range, 18–42 years. During a minimum duration of follow-up of 36 months, multiple imaging techniques including X-ray and computed tomography (CT) scanning were used to evaluate the radiological results, and Harris hip score (HHS) and the visual analogue scale (VAS) were chosen to assess the clinical results. Both treatment group and control group had a significant improved HHS (P < 0.001). The minimum clinically important difference (MCID) for HHS was reached in 91.7% of treatment group and 68.2% of control group (P = 0.0449). HHS in treatment group was significantly higher than control group at the last follow-up (P = 0.0254). VAS score was significantly declined in treatment group when compared with control group (P = 0.0125). Successful clinical results were achieved in 21 of 24 patients (87.5%) in treatment group compared with 13 of 22 patients (59.1%) in control group (P = 0.0284). Successful radiological results were achieved in 19 of 24 patients (79.2%) in treatment group compared with 11 of 22 patients (50%) in control group (P = 0.0380). The survival rates using requirement for further hip surgery as an endpoint were higher in treatment group in comparison to control group (P = 0.0260). The PRP incorporated autologous granular bones graft is a safe and effective procedure for the treatment of pre-collapse stages (ARCO stage II-III) of post-traumatic ONFH.
We evaluated the outcome of treatment of nonunion
of an intracapsular fracture of the femoral neck in young patients
using two cannulated screws and a vascularised bone graft. A total
of 32 patients (15 women and 17 men, with a mean age of 36.5 years;
20 to 50) with failed internal fixation of an intracapsular fracture
were included in the study. Following removal of the primary fixation,
two cannulated compression screws were inserted with a vascularised
iliac crest bone graft based on the ascending branch of the lateral
femoral circumflex artery. At a mean follow-up of 6.8 years (4 to 10), union was achieved
in 27 hips (84%). A total of five patients with a mean age of 40.5
years (35 to 50) had a persistent nonunion and underwent total hip
arthroplasty as also did two patients whose fracture united but
who developed osteonecrosis of the femoral head two years post-operatively. Statistical
analysis showed that younger patients achieved earlier and more
reliable union (p <
0.001). The functional outcome, as assessed
by the Harris Hip score, was better in patients aged <
45 years
compared with those aged >
45 years (p <
0.001). These findings suggest that further fixation using two cannulated
compression screws and a vascularised iliac crest bone graft is
an effective salvage treatment in patients aged <
45 years, in
whom osteosynthesis of a displaced intracapsular fractures of the
femoral neck has failed. Cite this article:
We present the long-term results of simple varus intertrochanteric osteotomy for osteonecrosis of the femoral head. We followed 26 hips in 20 patients, with a mean age at the time of surgery of 36 years, for a mean of 12.5 years. The mean varus angulation was 23°. The outcome in 19 of the hips (73%) was good or excellent; seven (27%) had a fair or poor result, with four needing some form of prosthetic arthroplasty. Simple varus intertrochanteric osteotomy is indicated, even if the extent of the capital infarct comprises more than 50% of the diameter of maximum radial distance from the circumference, provided that after operation the medial necrotic lesion measures less than two-thirds of the weight-bearing area, and the superolateral bone is normal.
We performed a prospective study using MRI to evaluate early necrosis of the femoral head in 48 patients receiving high-dose corticosteroids for the treatment of various autoimmune-related disorders. The mean interval from the initiation of corticosteroid therapy to the first MRI examination was 2 months (0.5 to 6). MRI was repeated, and the mean period of follow-up was 31 months (24 to 69). Abnormalities were found on MRI in 31 hips (32%). The initial changes showed well-demarcated, band-like zones which were seen at a mean of 3.6 months after initiation of treatment with steroids. In 14 of these hips (45%) there was a spontaneous reduction in the size of the lesions about one year after treatment had started, but there was no further change in size with a longer follow-up.
In early stage osteonecrosis of the femoral head (ONFH), core decompression (CD) is often performed; however, approximately 30% of CD cases progress to femoral head collapse. Bone healing can be augmented by preconditioning MSCs (pMSCs) with inflammatory cytokines. Another immunomodulatory approach is the timely resolution of inflammation using cytokines such as IL-4. We investigated the efficacy of pMSC and genetically modified MSCs that over-express IL-4 (IL4-MSCs) on steroid-associated ONFH in rabbits. Thirty-six male skeletally mature NZW rabbits received methylprednisolone acetate (20mg/kg) IM once 4 weeks before surgery. There were 6 groups:
CD alone – a 3 mm drill hole
hydrogel (HG) - 200 μl of hydrogel carrier MSCs–1 million rabbit MSCs pMSC - LPS (20 μg/ml) + TNFα (20 ng/ml) preconditioned MSCs IL4-MSCs – rabbit IL-4 over-expressing MSCs IL4-pMSCs – preconditioned IL-4 over-expressing MSCs Eight weeks after surgery, femurs were harvested, and evaluated by microCT, biomechanical, and histological analyses.Introduction
Methods
The purpose of the present study was to describe the long-term results of THA for ONFH in patients with SLE. From 1994–2001, 18 cementless THAs (14 SLE patients) were included in the present study. Four hips (3 patients) were lost to follow-up. The remaining 14 hips (11 patients) were available for evaluation. The mean follow-up period was 13.1(range, 10.0–16.4) years. The follow-up rate was 77.8%. The mean age at the time of surgery was 35.2 (range, 27.4–51.0) years.Objectives
Methods
Introduction:
For many years, minimally invasive joint-preserving regenerative therapy has been desired for the early stages of osteonecrosis of the femoral head (ONFH). In an animal study using adult rabbits, we reported that a single local injection of rhFGF-2-impregnated gelatin hydrogel, which has superior slow-release characteristics, suppresses the progression of femoral head necrosis. The purpose of this study was to evaluate the safety and clinical outcomes of a single local administration of rhFGF-2-impregnated gelatin hydrogel for the precollapse stage of ONFH. Patients and Methods: Ten patients with femoral heads up to precollapse stage 2 underwent a single local administration of 800-µg rhFGF-2-impregnated gelatin hydrogel and were followed up for two years. The eligibility criteria were age between 20 and 80 years and presence of ONFH at precollapse stage 1 or 2 according to the classification system for ONFH developed by the Japanese Investigation Committee of Health and Welfare. Primary outcomes included adverse events and complications. Secondary outcomes included changes in Harris Hip Scores (HHS), visual analog scale pain scores (VAS), the University of California, Los Angeles (UCLA) activity rating scores, radiological changes as determined via radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) of the hip joint. Results: We included five men (five hips) and five women (five hips), with a mean age of 39.8 years (range: 29–53 years) at the time of surgery. Eight patients had bilateral ONFH, three had already undergone THA on the contralateral side. Eight patients were receiving treatment with corticosteroid therapy, and two patients overused alcohol. Stage 1 and 2 disease was present in one and nine patients, respectively. One patient each had type A, type B, and type C1 disease, whereas seven patients had a type C2 lesion. All Adverse events were recovered without problem. The surgery was performed with a minimally invasive technique based core decompression (1 cm of skin incision), and walking was allowed from the day after surgery. Mean clinical scores improved significantly after three year compared with before surgery (before vs. after: VAS for pain, 21.2 vs. 5.3 mm; UCLA activity score 5.5 vs. 6.6; HHS, 81.0 vs. 98.4 points, respectively). There was only one case of femoral head collapse, and it had the greatest necrosis volume fraction and was considered to be in the early collapse stage at the time of operation. The other nine cases did not involve ONFH stage progression, and collapse was prevented. CT images and recent MRI postoperatively confirmed bone regeneration and reduction of the necrotic area. Conclusion: Clinical application of rhFGF-2-impregnated gelatin hydrogel for patients with precollapse stage of ONFH was feasible and safe. Our research is ongoing, further phase II multiple center study has been started in January 2016.Introduction