S3-Guideline non-traumatic adult femoral head necrosis

Implantation of Culture-Expanded Bone Marrow Derived Mesenchymal Stromal Cells for Treatment of Osteonecrosis of the Femoral Head

BACKGROUND

Although core decompression (CD) with stem cell for the treatment of osteonecrosis of the femoral head (ONFH) showed promising results in many reports, the efficacy remains uncertain. We aimed to evaluate the efficacy of CD with culture-expanded autologous bone marrow-derived mesenchymal stem cell (BM-MSC) implantation in early stage ONFH.

METHODS

A total of 18 patients (22 hips) with ONFH who underwent CD with culture-expanded BM-MSC implantation from September 2013 to July 2020 were retrospectively reviewed. The median age was 35.0 years [interquartile range (IQR), 28.5-42.0], and the median follow-up period was 4.0 years (IQR, 2.0-5.3). The median number of MSCs was 1.06 × 108. To evaluate radiographic and clinical outcomes, Association Research Circulation Osseous (ARCO) classifications, Japanese Investigation Committee classification, combined necrotic angle (CNA) visual analogue scale (VAS) and Harris Hip Score (HHS) were checked at each follow-up.

RESULTS

The preoperative stage of ONFH was ARCO 2 in 14 hips and ARCO 3a in 8 hips. The ARCO staging was maintained in 7 hips in ARCO 2 and 4 hips in ARCO 3a. The radiographic failure rate of ARCO 2 and 3a was 14.3 and 50%, respectively. Furthermore, CNA decreased to more than 20° in 6 hips (four were ARCO 2 and two were ARCO 3a).There was no significant difference in the VAS and HHS (P = 0.052 and P = 0.535, respectively). Total hip arthroplasty was performed in 4 hips.

CONCLUSION

CD with culture-expanded autologous BM-MSCs showed promising results for the treatment of early stage ONFH.

Canadian Association of Radiologists Musculoskeletal System Diagnostic Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Musculoskeletal System Expert Panel consists of musculoskeletal radiologists, a family physician, a sports and exercise medicine physician, emergency medicine physicians, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 25 musculoskeletal clinical/diagnostic scenarios, a systematic rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for 1 or more of these clinical/diagnostic scenarios. Recommendations from 41 guidelines (50 publications) and contextualization criteria in the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) for guidelines framework were used to develop 124 recommendation statements across the 25 scenarios related to the evaluation of the musculoskeletal system. This guideline presents the methods of development and the recommendations for imaging in the context of musculoskeletal pain, infection, tumors, arthropathies, metabolic bone disease, stress injuries, orthopedic hardware, avascular necrosis/bone infarction, and complex regional pain syndrome.

Core decompression combined with platelet-rich plasma-augmented bone grafting for femur head necrosis: a systematic review and meta-analysis

BACKGROUND

The clinical potential of biologic augmentation in core decompression and bone grafting for femoral head necrosis is widely acknowledged, with platelet-rich plasma (PRP) being a frequently employed biologic adjunct. However, its clinical application is not standardized, and high-level evidence is lacking. This study aimed to evaluate the efficacy and safety of core decompression and bone grafting combined with PRP for femur head necrosis.

METHODS

Several databases were systematically retrieved for randomized controlled trials comparing core decompression and bone grafting combined with or without PRP. A systematic review and meta-analysis were conducted following the PRISMA 2020 and AMSTAR 2 guidelines. The study is registered with PROSPERO under the code CRD42022361007, and it is also listed in the research registry under the identification number reviewregistry1537.

RESULTS

Eleven studies with 642 participants (742 hips) were included. The pooled estimates revealed that when core decompression and bone grafting were combined with PRP, the Harris hip score (mean difference: 7.98; 95% CI: 5.77-10.20; P <0.001), visual analog scale (SMD: -0.68; 95% CI: -0.96 - -0.40; P <0.001) and the pain component of Harris hip score (SMD: 8.4; 95% CI: 4.12-12.68; P <0.001), and reduction of radiographic progression [risk ratio (RR): 0.40; 95% CI: 0.27-0.59; P <0.001] were superior to core decompression and bone grafting alone. Fewer patients with treatment failure (RR: 0.27; 95% CI: 0.14-0.52; P <0.001) and higher good-to-excellent results (RR: 1.48; 95% CI: 1.17-1.86; P <0.001) were observed in treatment groups than control groups. Meanwhile, the pooled analysis substantiated the superior safety profile of PRP (RR: 0.29; 95% CI: 0.11-0.77; P =0.01).

CONCLUSIONS

The combination of core decompression and bone grafting with PRP is superior to the approach without PRP, demonstrating enhanced effectiveness in terms of function, pain relief, and radiographic progression. Additionally, it results in lower rates of treatment failure and adverse events. However, further high-quality RCTs are needed to evaluate their effectiveness due to methodological and implementation limitations observed in the existing evidence.

Mechanical parameter assessment of fresh human cancellous bone of the femoral head in atraumatic femoral head necrosis and primary coxarthrosis

BACKGROUND

Atraumatic femoral head necrosis is a rare pathological change of the femoral head. It is characterized by local necrosis of the cancellous bone as a result of reduced blood supply to the bone. Even today it remains unclear how to assess the hardness of the necrosis, whether it is soft tissue that is easily removed, or hard tissue that is difficult to resect.

METHODS

Femoral heads with primary coxarthrosis were selected as a comparison group. For this purpose, 49 femoral heads obtained during total hip arthroplasty surgery with either condition (23 femoral head necrosis, 26 coxarthrosis) were transferred to the testing laboratory in fresh condition. Cylindrical specimens were obtained using a tenon cutter along the main trabecular load direction in the subchondral region of the femoral head. Additionally, thin bone slices were extracted proximal and distal to the specimens for density measurements. Brass plates were glued to the circular surfaces of the specimens. After curing of the adhesive, the specimens were mounted in the testing machine and destructive uniaxial compression tests were conducted.

FINDINGS

The recorded mean compressive strengths and elastic moduli were almost identical for both groups, but the necrosis group showed significantly higher data scattering and range regarding the elastic modulus. The mean density of the coxarthrosis specimens was significantly higher than that of the necrotic specimens.

INTERPRETATION

The mechanical properties of cancellous bone vary considerably in the presence of femoral head necrosis. The existence of hard necrosis implies a potential challenge regarding the clinical resection of these tissues.

Comparison of two joint-preserving treatments for osteonecrosis of the femoral head: core decompression and core decompression with additional cancellous bone grafting

OBJECTIVE

Femoral head necrosis (FHN) affects mostly young and active people. The most common operative therapy is core decompression (CD) with optional cancellous bone grafting (CBG). Because little information is available on the long-term results of these procedures, we investigated the effectiveness of CD and CD + CBG in patients with ARCO stage II FHN in terms of postoperative pain, range of motion, patient-reported outcome measures (Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, EuroQol 5D, and Short Form 36 Questionnaire), and disease progression.

METHODS

We retrospectively compared 11 patients treated with CD alone 48.0 months (range, 26.3-68.5 months) postoperatively versus 11 patients treated with CD + CBG 69.2 months (range, 38.0-92.9 months) postoperatively. All patients were assessed according to a routine clinical protocol involving a clinical examination, questionnaires, and radiological imaging (X-ray and magnetic resonance imaging).

RESULTS

The clinical and radiological results showed no significant differences between the two groups. Both interventions demonstrated equal results according to clinical scores.

CONCLUSIONS

Our data may encourage application of the less invasive technique of CD alone without CBG, which is more surgically demanding. Further prospective studies with longer follow-up are necessary to clarify the risk factors for therapy failure.

Identification of hub genes and therapeutic drugs in osteonecrosis of the femoral head through integrated bioinformatics analysis and literature mining

Osteonecrosis of the femoral head (ONFH) is a multifactorial disease leading to severely limited function. By far, the etiology and pathogenesis of ONFH are not fully understood, and surgery is the only effective way to treat ONFH. This study aims to identify hub genes and therapeutic drugs in ONFH. Two gene expression profiles were downloaded from the gene expression omnibus database, and the hub genes and candidate drugs for ONFH were identified through integrated bioinformatics analysis and cross-validated by literature mining. A total of 159 DEGs were identified. PTGS2, LRRK2, ANXA5, IGF1R, MCL1, TIMP2, LYN, CD68, CBL, and RUNX2 were validated as 10 hub genes, which has considerable implications for future genetic research and related research fields of ONFH. Our findings indicate that 85 drugs interact with ONFH, with most drugs exhibiting a positive impact on ONFH by promoting osteogenesis and angiogenesis or inhibiting microcirculation embolism, rather than being anti-inflammatory. Our study provides novel insights into the pathogenesis, prevention, and treatment of ONFH.

Optimal drilling at femoral head-neck junction for treatment of the femoral head necrosis: Experimental and numerical evaluation

BACKGROUND

Advanced core decompression (ACD) is a relative new technique for treatment of early stages of avascular femoral head necrosis. Although it is a promising treatment option, there is a need to modify this technique for achieving higher hip survival rates. An idea was to combine this technique with the lightbulb procedure in order to get a complete removal of the necrosis. This study aimed at evaluating the fracture risk of the femora treated by the combined Lightbulb-ACD technique as the basis for clinical application.

METHODS

Subject-specific models were generated from CT scan data of five intact femora. Several treated models were then created from each intact bone and simulated during normal walking activity. Biomechanical testing was additionally performed on 12 pairs of cadaver femora to confirm the simulation results.

FINDINGS

The finite element results revealed that the risk factor of the treated models with a 8 mm-drill increased, but was not significantly greater than that of their corresponding intact models. However, for the femur treated with a 10 mm-drill, the risk factor increased significantly. Fracture always initiated on the femoral neck, i.e. it was either subcapital or transcervical fracture. Our biomechanical testing results correlated well with the simulation data which confirmed the usefulness and effectiveness of the bone models.

INTERPRETATION

The combined Lightbulb-ACD technique using a 10 mm drill increased the fracture risk of femur postoperatively. A drill of up to 8 mm at the anterior head-neck junction did not however lead to the weakening of the femur so that full load bearing may be possible.

Avascular necrosis of the femoral head: three-dimensional measurement of drilling precision reveals high accuracy and no difference between fluoroscopically controlled core decompression and cancellous bone grafting

INTRODUCTION

Avascular osteonecrosis of the femoral head (AVN) is a widespread disease affecting mostly young and active people, often exacerbating in progressive stages, ending in joint replacement. The most common joint preserving operative therapy for early stages is core decompression (CD), optional with cancellous bone grafting (CBG). For success it is vital that the necrotic area is hit and the sclerotic rim is broken by drilling into the defect zone to relieve intraosseous pressure. The aim of this study was to investigate if both techniques are precise enough to hit the center of the necrosis and if there is a difference in precision between drilling with small pins (CD) and the trephine (CBG).

PATIENTS AND METHODS

10 patients underwent CD, 12 patients CBG with conventional C-arm imaging. Postoperatively 3D MRI reconstructions of the necrotic area and the drilling channels were compared. The deviation of the drilling channel from the center of the necrotic area was measured. PROMs (HHS, HOOS, EQ-5D, SF-36) were evaluated to compare the clinical success of these procedures.

RESULTS

Neither with CD nor with CBG the defect zone was missed. The drilling precision of both procedures did not differ significantly: distance to center 3.58 mm for CD (range 0.0-14.06, SD 4.2) versus 3.91 mm for CBG (range 0.0-15.27, SD 4.7). PROMs showed no significant difference.

CONCLUSION

Concerning the most important difference between the two procedures-the surgical higher demanding technique of CBG-we suggest applying the less invasive technique of CD alone.

Denosumab Can Prevent Collapse in Patients with Early-Stage Steroid-Induced Osteonecrosis of the Femoral Head by Inhibiting Osteoclasts and Autophagy

OBJECTIVE

The osteoclastic bone resorption inhibitors might have positive effect in preventing femoral head collapse in patients with osteonecrosis of the femoral head (ONFH). However, as a novel osteoclastic inhibitor, whether denosumab can prevent collapse in steroid-induced ONFH remains unknown. This study aims to evaluate the treatment effect of denosumab and the potential protective mechanism.

METHODS

This was a retrospective study. A total of 161 patients with steroid-induced ONFH who underwent denosumab treatment were reviewed, and 209 untreated patients were selected as controls. Their clinical characteristics and radiological exam results were obtained. Patients were treated with 60 mg denosumab every 6 months for 2 years. The primary outcome was the incidence of femoral head collapse at 2 years after the initial diagnosis of ONFH. Secondary outcomes included the Harris hip score, progression of osteosclerosis, increase in necrotic area, bone marrow oedema relief, and bone mineral density increase in the femoral head. The Mann-Whitney U test and chi-square tests were performed to identify the differences between the continuous and categorical variables, respectively. A multivariate logistic regression model was built to identify the factors associated with the treatment effect of denosumab.

RESULTS

The incidence of femoral head collapse was 42.24% (68/161) in the denosumab group and 54.07% (113/209) in the control group (χ²  = 5.094, p = 0.024; relative risk = 0.787, 95% CI = 0.627-0.973). The excellent-good rates of the Harris hip score were 63.98% (103/161) in the denosumab group and 44.98% (94/209) in the control group (χ²  = 13.186, p < 0.001). The incidence of osteosclerosis progression in the denosumab group was 55.28% (89/161), which was significantly higher than that in the control group (43.54%, 91/209, χ²  = 5.016, p = 0.025). Meanwhile, a significant increase in bone mineral density was identified in 29.19% (47/161) and 7.18% (15/209) of patients in the denosumab and control groups, respectively (χ²  = 31.600, p < 0.001). The osteoclastic cytoplasm expression of LC3-II was more positive in the control group than in the denosumab group (immunohistochemistry scoring: 3.58 ± 2.27 vs 6.33 ± 2.64, Z = -2.684, p = 0.007). A total of three independent factors were considered to be associated with the positive treatment effect of denosumab, the time of first denosumab administration (OR = 2.010, 95% CI = 1.272-3.177), osteosclerosis (OR = 1.583, 95% CI = 1.024-2.445), and the necrotic area before denosumab administration (medium necrotic area: OR = 2.084, 95% CI = 1.245-3.487; large necrotic area: OR = 2.211, 95% CI = 1.255-3.893).

CONCLUSIONS

The current study demonstrated that denosumab had a positive effect on preventing femoral head collapse in patients with steroid ONFH. This effect might be closely associated with the inhibition of osteoclasts and their autophagy.

[The importance of removing osteonecrosis during treatment of femoral head osteonecrosis]

Atraumatic femoral head necrosis (aFHN) in adults is estimated to be the leading cause of approximately 10% of all hip prosthesis implantations. Due to the relatively frequent occurrence of aFHN at a young age, the possibility of a joint-preserving intervention should be examined. This includes the classic "core decompression" and modifications based on it. There are different data on the success rates of this method. Reasons for treatment failure could include a lack of clearance of the necrosis zone. The clearance of the necrosis zone is taken into account by alternative surgical procedures for the treatment of aFHN. These are the "trap-door procedure", the "light-bulb procedure" and "advanced core decompression". The current state of knowledge on these procedures is reviewed in this keynote article. It is shown that the extensive excision of femoral head necrosis is of particular importance. None of the procedures mentioned can currently be recommended in preference over the others.

Multiple Drilling with Recombinant Human Bone Morphogenetic Protein-2 in Korean Patients with Non-Traumatic Osteonecrosis of the Femoral Head: A Prospective Randomized Pilot Study with a Minimum Two-Year Follow-Up

We sought to determine whether multiple drilling (MD) combined with the injection of recombinant human bone morphogenetic protein-2 (rhBMP-2) and β-tricalcium phosphate (β-TCP) could improve survival of the femoral head in pre-collapse lesions of non-traumatic osteonecrosis of the femoral head (ONFH) as compared with MD alone. We conducted a single-site, off-label, comparative and prospective cohort study between November 2017 and May 2019. We enrolled 25 hips (25 patients) with non-traumatic ONFH (Ficat–Arlet stage 2A or less). We performed a survival analysis, and the primary outcome was the occurrence of femoral head collapse on follow-up radiograph. Our cohort consisted of 11 men and 9 women of age 52.5 ± 8.8 years and a body mass index of 24.3 ± 3.0 kg/m². The femoral heads were preserved in 9 hips (45.0%) and collapsed in 11 hips (55.0%) at the final follow-up; mean survival to collapse was 6.9 (range 2.8–13.5) months. There were no significant differences in the survival of the femoral head between the MD alone group and the MD with rhBMP-2 and β-TCP group (five hips survived, 50% vs. four hips survived, 40%, respectively; p = 0.83). MD combined with the injection of rhBMP-2 and β-TCP did not improve femoral head survival compared to MD alone in the pre-collapse non-traumatic ONFH lesion.

Feasibility of a preoperative strengthening exercise program on postoperative function in patients undergoing hip or knee arthroplasty: a pilot randomized controlled trial

BACKGROUND

There are conflicting results on the effect of preoperative exercise programs on long-term function and little evidence on short-term function. The aim is to assess the feasibility of a preoperative strengthening exercise program in patients undergoing hip or knee joint arthroplasty in terms of trial design, recruitment, and follow-up rates.

METHODS

A randomized controlled feasibility study with patients undergoing hip or knee joint arthroplasty. Patients were randomized to a preoperative strengthening exercise program or standard of care. Feasibility outcome measures were recruitment rate (≥ 50%) and loss to follow-up (≤ 15%).

RESULTS

Of the 129 eligible participants, 63 participants consented to participate in the study (49%), and 27 were successfully randomized prior to surgery (43%). All 27 participants completed the baseline assessment. Of these, 6 (22%) had surgery during the exercise period. Of the remaining 21 participants, 20 (95%) completed the pre-surgery assessment. The study was terminated before five participants could be eligible for the 6-month assessment. Sixteen (76%) participants completed the 6-week post-surgery assessment. Twelve participants completed the 6-month assessment (75%).

CONCLUSION

Given the recruitment rate, randomization barriers, and study participant loss to follow-up, the study was discontinued since it was not considered feasible in this current form at our clinical site despite modifications made to the protocol. Future investigations into a modified intervention via telerehabilitation should be explored.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03483519 . Retrospectively registered in March 2018.

Atraumatic femoral head necrosis: a biomechanical, histological and radiological examination compared to primary hip osteoarthritis

INTRODUCTION

Atraumatic necrosis of the femoral head (AFHN) is a common disease with an incidence of 5000-7000 middle-aged adults in Germany. There is no uniform consensus in the literature regarding the configuration of the bone in AFHN. The clinical picture of our patients varies from very hard bone, especially in idiopathic findings, and rather soft bone in cortisone-induced necrosis. A better understanding of the underlying process could be decisive for establishing a morphology-dependent approach. The aim of this study is the closer examination of the condition of the bone in the AFHN compared to the primary hip osteo arthritis (PHOA).

MATERIALS AND METHODS

The preparations were obtained as part of elective endoprosthetic treatment of the hip joint. Immediately after sample collection, thin-slice CT of the preserved femoral heads was performed to determine the exact density of the bone in the necrosis zone. Reconstruction was done in 0.8-1 mm layers in two directions, coronary and axial, starting from the femoral neck axis. Density of the femoral heads was determined by grey value analysis. The value in Hounsfield units per sample head was averaged from three individual measurements to minimize fluctuations. For biomechanical and histomorphological evaluation, the samples were extracted in the load bearing zone perpendicular to the surface of the femoral head. Group-dependent statistical evaluation was performed using single factor variance analysis (ANOVA).

RESULTS

A total of 41 patients with a mean age of 64.44 years were included. The mean bone density of the AFHN samples, at 1.432 g/cm³, was about 7% higher than in the PHOA group with a mean value of 1.350 g/cm³ (p = 0.040). The biomechanical testing in the AFHN group showed a 22% higher-but not significant-mean compressive strength (20.397 MPa) than in the PHOA group (16.733 MPa). On the basis of histological analysis, no differentiation between AFHN and PHOA samples was possible.

CONCLUSIONS

The present study (NCT, evidence level II) shows that AFHN has a very well detectable higher bone density compared to PHOA. However, neither biomechanical stress tests nor histomorphological evaluation did show any significant difference between the groups. The results allow the conclusion that there is no "soft" necrosis at all in the AFHN group.

Singleton-Merten syndrome: A rare cause of femoral head necrosis

Singleton-Merten syndrome (SMS) is a type I interferonopathy. In this report, we disclose the first-to the best of our knowledge-direct association of SMS with femoral head necrosis (FHN). The following case report presents the condition of a 38-year-old male suffering from SMS with FHN, characterized by acute symptoms and rapid disease progression. As per the recommendations of the Association Research Circulation Osseous (ARCO) and the S3-guidelines, we successfully treated the FHN with core decompression. Our histological results correlate with the changes described in medical literature in patients with SMS and MDA5-knockout in vivo experiments such as osteopenia, widened medullary cavity, and thin cortical bone. Moreover, the conducted immunohistochemistry shows strong CD56 positivity of the osteoblasts and osteocytes, as well as significant CD68 and CD163 positivity of the middle-sized osteoclasts. Collectively, these findings suggest an underlying syndrome in the FHN. A six-month post-operative follow-up revealed complete recovery with the absence of the initial symptoms and ability to resume normal daily activities. Taken together, our findings suggest that SMS is an additional cause of FHN in young adults. Early detection and adequate treatment using well-established joint-preserving techniques demonstrate a favorable improvement of the patient's clinical condition.

Multiple drilling is not effective in reducing the rate of conversion to Total hip Arthroplasty in early-stage nontraumatic osteonecrosis of the femoral head: a case-control comparative study with a natural course

BACKGROUND

To determine whether multiple drilling is effective in postponing the need for total hip arthroplasty (THA) in early-stage nontraumatic osteonecrosis of the femoral head (ONFH).

METHODS

We identified 514 patients who were diagnosed with early-stage ONFH between January 2008 and December 2018. One hundred ninety-six patients underwent multiple drilling, and 318 patients had a natural course of progression. One hundred fifty-nine patients were selected for each group after case-control matching for preoperative demographics and modified Ficat and Arlet stage. The rates of THA conversion were compared. We also performed Cox regression to identify risk factors associated with THA conversion in patients who underwent multiple drilling.

RESULTS

Kaplan-Meier survivorship with an endpoint of THA for nontraumatic reasons were not significantly different between the multiple drilling group (75.6, 95% confidence interval 67.8-83.4%) and the natural course group (72.2, 95% confidence interval 64.8-79.6%) at 5 years (log-rank, P = .191). In the Cox regression model, a larger extent of necrotic lesion, bone marrow edema (BME), and higher postoperative work intensity significantly increased the risk of THA conversion (P < .05). Among patients treated with autogenous bone grafting, there was a lower risk of failure in patients with necrotic lesion less than 15% (P < .05).

CONCLUSIONS

Multiple drilling is not effective in reducing the rate of THA conversion in early-stage nontraumatic ONFH. The risk of conversion to THA after multiple drilling is increased by a larger extent of necrotic lesion, presence of BME, and higher postoperative work intensity in patients with early-stage ONFH.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry ( ChiCTR2000035180 ) dated 2 August 2020.

The efficacy of acupuncture and moxibustion for early and middle-stage osteonecrosis of the femeral head: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Osteonecrosis of the femeral head (ONFH) occurs predominantly in young- and middle-aged people, and the disability rate is high in the late stage of the disease and most patients have to undergo total hip replacement. Clinically, increasing attention is paid to intervening early and middle-stage ONFH so as to delay its progress. Acupuncture and moxibustion (AM) is a unique method for treating ONFH in China. This study aims to summarize the advantages of AM for the treatment of ONFH.

METHODS

A comprehensive literature search was conducted on the database with languages of English and Chinese. The medical subject titles used are "Osteonecrosis of the femoral head" and "acupuncture and moxibustion." Related words in the title or abstract including but were not limited to "necrosis of the femoral head," "avascular necrosis of the femoral head," "ischemic necrosis of the femoral head," "caput femoris necrosis," "bone paralysis," "bone erosion," and "bone atrophy."

RESULTS

Nine randomized controlled trials were identified in this meta-analysis that included 630 subjects. Meta-analysis showed that the trial group that treated with conventional therapy combined with AM had a higher effective rate (Z = 2.27 P = 0.02) and excellent and good rate (Z = 4.85 P < 0.00001) and Harris hip function score (HHS) (Z = 2.31 P = 0.02) and lower incidence of related adverse reactions during treatment (Z = 2.82 P = 0.005) compared with the control group that treated with conventional therapy alone.

CONCLUSIONS

AM for early and middle-stage ONFH is an effective and relatively safe intervention, which can improve the effective rate and excellent and good rate and HHS, and reduce the adverse reaction rate. Clinically, early and middle-stage ONFH can be intervened by combining with AM while taking conventional therapy to improve the efficacy.

Association of ABCB1 and CYP450 Gene Polymorphisms and their DNA Methylation Status with Steroid-Induced Osteonecrosis of the Femoral Head in the Chinese Population

Objective: Osteonecrosis of the femoral head (ONFH) is a severe pathological state with multiple etiologies. Steroid hormone metabolism-related genes play an important role in ONFH. The aim of this study was to investigate the relationships between polymorphisms of the drug-metabolizing enzyme gene, cytochrome P450 (CYP450), and the drug transporter gene, ATP-binding cassette subfamily B member 1 (ABCB1), as well as their DNA methylation status with the pathogenesis of steroid-induced ONFH. Methods: In this case-control study, we evaluated five single nucleotide polymorphisms (SNPs) in two genes in a Han Chinese population, including 79 patients with steroid-induced ONFH and 114 persons who took steroids but did not develop steroid-induced ONFH. SNPs were genotyped by the improved multiplex ligation detection reaction. MethylTarget technology was used to ascertain the methylation status at two CpG islands in the ABCB1 gene for statistical analysis. Finally, interactions between the SNPs and the CpG site's methylation levels were statistically analyzed by methylation quantitative trait locus. Results: We found that the T allele of the CYP450 rs2242480 locus was associated with steroid-induced ONFH risk reduction (odds ratio [OR] = 0.598, 95% confidence interval [CI]: 0.360-0.992, p = 0.046). In the genetic model analysis, the T allele of the rs2032582 locus in the ABCB1 gene was associated with a reduced risk of steroid-induced ONFH under the dominant model (OR = 0.465, 95% CI: 0.223-0.972, p = 0.042). The CpG sites with significant differences (p < 0.05) in methylation levels between the cases and controls were ABCB1_1_192…ABCB1_2_43. A total of 14 pairs of linear regression tests between SNPs and methylation sites demonstrated statistical significance (p < 0.05). Conclusions: This study provides evidence for two steroid-induced ONFH susceptibility genes (ABCB1, CYP450) in the Han Chinese population.

Cone beam-navigated core decompression of bone marrow edema syndrome

INTRODUCTION

The aim of the study was to compare decompression of bone-marrow edema or osteonecrosis of the proximal femur by means of a cone beam-based imaging and navigation system (cone beam-navigated decompression, CBND) with decompression by the conventional technique of drilling using fluoroscopy (FD).

MATERIALS AND METHODS

The data of patients with bone-marrow edema syndrome treated between 2016 and 2018 by drilling of the proximal femur in CBND or FD technique were compared retrospectively.

RESULTS

Each treatment group included 20 patients. The mean operating time for CBND was 16.4 ± 5.8 min, compared with 29.1 ± 20.8 min for FD (p = 0.018). The lesion was definitely reached by CBND in 19/20 patients. Eighteen of the 20 patients in the CBND group reported that their pain decreased after the treatment, compared with 12/20 patients in the FD group (p = 0.065). The radiation dosage was significantly higher (p < 0.001) for CBND than for FD.

CONCLUSION

Decompression by CBND can be carried out safely and without complications. The advantages of CBND over FD are the minimally invasive access and the ability to address the affected area precisely with only one drilling maneuver. The high radiation dose of CBND can be reduced using low-dose protocols.

Effectiveness of Iloprost in the Treatment of Bone Marrow Edema

Background and objective

Bone marrow edema (BME) is a rare condition caused by insufficient osseous blood supply and may result in severe pain that has adverse effects on patients’ life. To date, various conservative treatments have been recommended for the treatment of BME, including analgesics, immobilization of the affected extremity, and iloprost infusion. The aim of this retrospective study was to investigate the effectiveness of parenteral iloprost therapy in the treatment of BME detected in different skeletal locations.

Materials and methods

This retrospective study included 23 patients (17 men and six women) with BME who were classified as stage I-III according to the Association Research Circulation Osseous (ARCO) classification. BME was localized to the proximal femur in 13 (56.5%), the distal femur in four (17.4%), tarsal bone in four (17.4%), and tibial plateau in two (8.7%) patients. The mean age of the patients was 46.7 years and all the patients were evaluated with the Visual Analog scale (VAS), Functional Mobility Scale (FMS), and MRI.

Results

A significant improvement was observed in the post-treatment VAS and FMS scores of all patients compared to their pre-treatment scores. Moreover, the edema regressed completely in 60.9% of the patients at three months of MRI control. No serious side effects were observed during the treatment in any of the patients. However, transient side effects including headache, arrhythmia, and flushing were observed in five patients.

Conclusion

The present study indicated that iloprost therapy is an effective and safe option in the treatment of BME patients, particularly in the reduction of severe pain that has adverse effects on patients’ social life, regardless of ARCO staging. Moreover, this therapy could be particularly useful in reducing pain, improving functional recovery, and achieving complete regression of the edema on MRI in ARCO stage I-II patients.

Calcium dobesilate (Doxium®) in bone marrow edema syndrome and suspected osteonecrosis of the hip joint - A case series

Osteonecrosis of the femoral head is a disease that leads to gradual degeneration of the hip joint causing immobility and a devastating impairment of quality of life. Early stage disease is characterised by a bone marrow edema of the proximal femur, a sight it shares with bone marrow edema syndrome. Although total hip arthroplasty offers quick symptom relief and functionally appealing results the treatment remains challenging, with its particularly young patients and considering limited non-invasive treatment options. We treated 6 patients with bone marrow edema in MRI and suspected osteonecrosis of the hip joint with calcium dobesilate, a vasoactive agent used in the treatment of diabetic retinopathy. We could demonstrate rapid symptom relief and concomitant disease remission on control MRI in early stage disease without any adverse events. Patients at advanced stages benefited in terms of pain reduction, but the treatment failed to halt disease progression. To the best of our knowledge, this is the first report of the therapeutic administration of calcium dobesilate in patients with bone marrow edema syndrome or osteonecrosis of the hip joint.

Whole-joint magnetic resonance imaging to assess osteonecrosis in pediatric patients with acute lymphoblastic lymphoma

BACKGROUND

Osteonecrosis is a debilitating complication in children and adolescents with acute lymphoblastic leukemia or acute lymphoblastic lymphoma (LLy). An objective screening test to identify patients at risk for symptomatic, extensive joint involvement will help manage osteonecrosis.

METHODS

We performed a prospective, longitudinal pilot study with whole-joint magnetic resonance imaging (MRI) of shoulders, elbows, hips, knees, ankles, and hindfeet to evaluate the incidence and timing of osteonecrosis involving multiple joints in 15 patients with LLy aged 9-21 years at diagnosis.

RESULTS

Osteonecrosis affecting ≥30% of the epiphysis occurred in eight of 15 patients, with a high prevalence in hips (12 of 26 examined [46%]) and knees (10 of 26 [38%]) post reinduction I and in shoulders (seven of 20 [35%]) post reinduction II. Most osteonecrotic hips and knees with ≥30% epiphyseal involvement became symptomatic and/or underwent surgery (100% and 82%, respectively). All eight patients with ≥30% epiphyseal involvement had multijoint involvement. Seven of these patients had hip or knee osteonecrosis by the end of remission induction, and only these patients developed osteonecrosis that became symptomatic and/or underwent surgery in their hips, knees, shoulders, ankles, and/or feet; all of these joints were associated with epiphyseal abnormalities on post reinduction I imaging.

CONCLUSIONS

MRI screening in adolescent patients with LLy revealed osteonecrosis in multiple joints. Initial screening with hip and knee MRI at the end of induction may identify susceptible patients who could benefit from referrals to subspecialties, more extensive follow-up imaging of other joints, and early medical and surgical interventions.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today?: A 5-Year Update

➢. Clinicians should exercise a high level of suspicion in at-risk patients (those who use corticosteroids, consume excessive alcohol, have sickle cell disease, etc.) in order to diagnose osteonecrosis of the femoral head in its earliest stage. ➢. Nonoperative treatment modalities have generally been ineffective at halting progression. Thus, nonoperative treatment is not appropriate in early stages when one is attempting to preserve the native joint, except potentially on rare occasions for small-sized, medially located lesions, which may heal without surgery. ➢. Joint-preserving procedures should be attempted in early-stage lesions to save the femoral head. ➢. Cell-based augmentation of joint-preserving procedures continues to show promising results, and thus should be considered as an ancillary treatment method that may improve clinical outcomes. ➢. The outcomes of total hip arthroplasty in the setting of osteonecrosis are excellent, with results similar to those in patients who have an underlying diagnosis of osteoarthritis.

[Modified advanced core decompression (mACD)]

OBJECTIVE

The modified advanced core decompression (mACD) combines the advantages of a low invasive core decompression with maximal removal of osteonecrotic bone and a biologic reconstruction of the resulting bone defect.

INDICATIONS

Avascular (atraumatic) osteonecrosis of the femoral head (ARCO stage II).

CONTRAINDICATIONS

Subchondral fractures (ARCO stage III); advanced osteoarthritis (e.g., ACRO stage IV); persisting risk factors such as high-dose corticoid therapy, chemotherapy, alcohol abuse; open growth plates; history of side effects or intolerance to components of the applied bone substitute; lack of patient compliance; osteomyelitis or other septic conditions.

SURGICAL TECHNIQUE

Supine positioning on the operation table, skin disinfection, and sterile draping. Skin incision and core decompression using a 3.2 mm guide wire. Removal of a bone cylinder from a nonaffected area of the femoral neck using a hollow trephine. Drilling of the osteonecrotic area over the applied wire up to 5 mm to the subchondral bone under fluoroscopy, insertion of an expandable bone knife and removal of the osteonecrotic bone supported by a curette. Bone grafting of the autologous bone into the subchondral defect zone and filling of the drill canal by resorbable bone substitute.

POSTOPERATIVE MANAGEMENT

Bed rest for 24 h, then partial weight bearing (20 kg) on crutches for 2-6 weeks depending on the bone quality in the defect zone and the applied bone substitute.

RESULTS

Midterm superiority (2 years) in hip survival of the mACD over advanced core depression and core depression, especially in ARCO stage II.

Taohong Siwu decoction for femoral head necrosis: A protocol for systematic review

BACKGROUNDS

Femoral head necrosis is one of the most common orthopedic diseases which can be diagnosed in all ages with different reasons. Taohong Siwu decoction (TSD) has been widely used in the treatment of femoral head necrosis. However, as far as we know, there is still a lack of supporting evidence regarding the efficacy of TSD for femoral head necrosis. Therefore, this protocol aims to evaluate the effectiveness and safety of TSD for femoral head necrosis.

METHODS

Eight electronic databases, including PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, Web of Science, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Technology Periodical database, (Chinese Scientific Journal Database) and Wanfang Database will be searched from the time when the respective databases were established to January 2020. Randomized controlled trials of TSD in the treatment of femoral head necrosis will be collected. After evaluating the quality of methodology and extracting valid data, the final meta-analysis will be carried out with software Revman 5.3.

ETHICS AND DISSEMINATION

The results of this systematic review will offer implications of the use of TSD treatment for Femoral Head Necrosis. It uses aggregated published data instead of individual patient data and does not require an ethical board review and approval. The findings will be published in a peer-reviewed journal and disseminated in conference presentations.

RESULTS

The results of this study will offer implications of the use of TSD treatment for FHN with this meta-analysis.

CONCLUSION

The conclusion of this study will provide recent evidence to assess whether TSD is effective and safe in the treatment of FHN.

Nontraumatic avascular necrosis of the femoral head : Arthroscopic and navigation-supported core decompression

OBJECTIVE

The aim is to address core decompression and pathologies of the femoral head, treating them during the same procedure. Furthermore, radiation exposure will be reduced.

INDICATIONS

Femoral head necrosis ARCO (Association Research Circulation Osseous) stages I-III.

CONTRAINDICATIONS

Progressive femoral head necrosis as ARCO stages IIIC-IV.

SURGICAL TECHNIQUE

Arthroscopically navigated core decompression of the femoral head using an established optoelectronic system with fluoro-free software module. First, hip joint arthroscopy was performed and further pathologies were treated. Second, core decompression was navigated by a navigation pointer and drill sleeve to reach the correct target point. After visualization, the procedure is repeated 3-5 times.

POSTOPERATIVE MANAGEMENT

Limited weight bearing of the operated leg (20 kg) for 10-14 days. Active or passive continuous motion machine for 4 weeks. Adjuvant postoperative indomethacin therapy for 10 days to reduce pain and bone marrow edema.

RESULTS

From May 2018 to January 2019, 7 patients (male = 4; 40 ± 9 years) underwent arthroscopically navigated core decompression with 2 (29%) and 5 (71%) patients being classified as ARCO II and III, respectively. Preoperatively, all patients reported load-dependent pain. In all cases, we could identify synovitis, which results in soft tissue release and synovectomy. Furthermore, 4 of 7 patients had an additional labrum lesion, which is addressed by refixation or shrinking.

DISCUSSION

Compared to the conventional technique, this fluoro-free navigation procedure allows more precise drilling. Moreover, additional pathologies, as found in all our cases, could be simultaneously addressed. The intraoperative radiation exposure for the patient and surgical team could also be reduced. Although arthroscopically assisted core decompression requires more preparation time, there are advantages over conventional surgery.

[Total hip replacement in avascular femoral head necrosis]

BACKGROUND

Avascular necrosis of the femoral head is a progressive perfusion disorder of the hip joint. Progress in avascular necrosis causes structural damage to the affected joint, often requiring total hip replacement.

AIM

This article is intended to give the reader an overview of the current literature on total hip replacement of patients with an avascular necrosis of the femoral head.

RESULTS

Before 1990, patients with avascular necrosis of the femoral head had significantly higher revision rates after total hip replacement. Recent studies, however, showed no significant differences in clinical outcomes after total hip replacement in femoral head necrosis and primary osteoarthritis. Despite the young age of the patients, good long-term clinical results can be expected even in patients with an avascular necrosis of the femoral head after total hip replacement.

[Update of the German S3 guideline on atraumatic femoral head necrosis in adults]

The update of the German S3 guideline on atraumatic femoral head necrosis in adults aims to provide an overview of diagnosis and treatment. All clinical studies, systematic reviews, and meta-analyses published in German or English between 01.05.2013 and 30.04.2017 were included. Of 427 studies, 28 were suitable for analysis. Risk factors are corticosteroids, chemotherapy, kidney transplants, hemoglobinopathies, and alcoholism. Differential diagnoses are for example bone marrow edema, insufficiency fracture, and destructive arthropathy. Radiography should be performed upon clinical suspicion. In patients with normal radiography findings but persistent complaints, magnetic resonance imaging (ARCO classification) is the method of choice. Computed tomography (CT) can be used to confirm/exclude articular surface collapse. A subchondral sclerosis zone >30% in CT indicates a better prognosis. Left untreated, a subchondral fracture will develop within 2 years. The risk of disease development in the opposite side is high during the first 2 years, but unlikely thereafter. In conservative therapy, iloprost and alendronate can be used in a curative approach, the latter for small, primarily medial necrosis. Conservative therapy alone as well as other drug-based and physical approaches are not suitable for treatment. No particular joint-preserving surgery can currently be recommended. Core decompression should be performed in early stages with <30% necrosis. From ARCO stage IIIc or in stage IV, the indication for total hip arthroplasty should be checked. Results after total hip arthroplasty are comparable with those after coxarthrosis, although the revision rate is higher due to the relatively young age of patients. Statements on the effectiveness of cell-based therapies such as expanded stem cells or bone marrow aspirates cannot currently be made.

[Atraumatic and aseptic osteonecrosis of large joints]

Subchondral osteonecrosis of large weight-bearing joints (hip and knee joints) represents a severe and joint-threatening disease. Apart from idiopathic forms, glucocorticoid medication and alcohol abuse have been identified as major causative factors for atraumatic osteonecrosis. In addition to direct cytotoxic factors, a critically reduced perfusion of the subchondral osseous space will eventually lead to bone marrow ischemia and osseous necrosis. Magnetic resonance imaging (MRI) is capable of visualizing a reactive border-like zone in this early, already irreversible and often asymptomatic stage I according to the Association of Research Circulation Osseous (ARCO) staging system. Later in the course, osteonecrosis progresses to form serpiginous sclerotic lines, enclosing the necrotic bone area (stage II ARCO). Repair mechanisms of osteonecrosis are mostly unsuccessful and depending on the size of the osteonecrosis result in biomechanical failure and ultimately subchondral insufficiency fractures (crescent sign), thus marking the transition to stage III ARCO (joint surface collapse).

Treatment of Bone Marrow Edema of the Foot and Ankle With the Prostacyclin Analog Iloprost

BACKGROUND

Bone marrow edema (BME) of the foot and ankle is challenging to treat. One approach is intravenous Iloprost treatment, which is a vasoactive prostacyclin analog. The aim of this study was to evaluate the early and intermediate outcome of intravenous Iloprost therapy on BME of the foot and ankle and to analyze the influence of its etiology and Association Research Circulation Osseous (ARCO) stage on the outcome.

METHODS

This was a retrospective study with prospective follow-up. All patients treated by intravenous Iloprost for BME of the foot and ankle (ARCO I-III) at a single orthopedic reference center were included. Demographics, medical history, and MRIs were assessed prior to treatment (t0). MRIs were used to assess the BMEs' etiology (idiopathic/ischemic/metabolic, mechanical/degenerative, traumatic) and severity (ARCO). Complications as well as changes in pain, treatment, and MRI were evaluated after 3 months (t1). The following patient-rated outcome measures (PROMs) were assessed prospectively (t2): 12-Item Short Form Health Survey (SF-12), Visual Analog Scale Foot and Ankle (VAS FA), and the Foot Function Index (FFI) (also at t0). The descriptive outcomes and the influence of the etiology and ARCO on the outcome parameters were evaluated. Out of 70 eligible patients, 42 patients (60%; 47 ± 15 years; 30% female) with a mean follow-up of 28 ± 19 months were included.

RESULTS

Twelve patients reported minor complications during Iloprost therapy. At t1, pain decreased significantly in 56%, and the amount of BME decreased in 83% of patients. Both parameters correlated moderately (r = -0.463, P = .015). The PROMs at t2 revealed moderate results. The overall FFI improved from 59 ± 21 to 30 ± 22 ( P < .001), the overall VAS FA was 68 ± 20, the SF-12 Physical Component Summary 42 ± 12 and Mental Component Summary 50 ± 9. Subgroup analysis revealed no significant influence of the etiology or ARCO stage on any outcome measure.

CONCLUSION

Iloprost therapy for BME of the foot and ankle resulted in a 60% pain and 80% edema decrease after 3 months. After 2 years, patient-rated outcome measures showed residual impairment. Neither the etiology nor ARCO stage significantly influenced the outcome.

LEVEL OF EVIDENCE

Level III, comparative study.

Short stem survival after osteonecrosis of the femoral head

INTRODUCTION

Short stems were developed as a bone-conserving alternative especially for the young hip arthroplasty patient. Patients suffering from osteonecrosis of the femoral head are frequently younger than primary arthritis patients. The outcome of short stems in these patients remains unclear. The aim of our study was to compare mid-term survival of short stems after osteonecrosis of the femoral head (ONFH) and primary arthritis.

MATERIALS AND METHODS

Data on short stem implantations over a 10-year period were collected. Demographic data and X-ray measurements before and after surgery were recorded. Indication for operation was determined from medical records and X-rays. Patients were asked by post about any revision. Reason for revision was identified by analysis of operation protocols. Short stem revision rates were analyzed using Kaplan-Meier charts, comparing 212 ONFH patients (231 operations) and 1284 primary arthritis patients (1455 operations).

RESULTS

Follow-up time averaged 5.3 and 6 years and was complete for 92% (ONFH) and 94% (primary arthritis) of the patients. ONFH patients were significantly younger (53 years vs. 59 years, p < 0.001) and more frequently male (55 vs. 42%, p < 0.001). The total revision rate did not differ between the two groups (8 years: 4.2 vs. 5.6%, p = ns). A trend towards more stem revisions was detected for ONFH patients (3 vs. 1.8%, p = ns). The aseptic stem loosening rate was significantly elevated for osteonecrosis patients (8 years: 2.6 vs. 0.7%, p = 0.013).

CONCLUSIONS

Our study showed elevated short stem loosening rates after ONFH. Similar results are published for classic cementless stems. The question of which stem is best for the young osteonecrosis patient cannot be answered yet. Consecutive studies directly comparing loosening rates of short and classic cementless stems in young osteonecrosis patients are required.

Avascular Necrosis of Bone following Chemotherapy in Cancer Patients with Coagulopathy: Report of Two Cases

We report 2 cases of patients with solid tumors and coagulopathy who experienced avascular necrosis (AVN) of the bone following chemotherapy. Both cases exhibited nontraumatic bilateral AVN of the femoral heads, and one also showed bilateral AVN of the humeral heads. One case had multiple thromboembolic complications, including pulmonary obstructive syndrome and paraneoplastic pain. The other showed multiple paraneoplastic syndromes, with hypercalcemia and thrombocytosis. Groin pain and claudication of the lower extremities developed and persisted. Both patients eventually received bilateral hip arthroplasty due to AVN of both femoral heads.

Cortisol inhibits mTOR signaling in avascular necrosis of the femoral head

BACKGROUND

ANFH is a major health problem, to which long lasting and definitive treatments are lacking. The aim of this study is to study RNA alterations attributed to cortisol-induced ANFH.

METHODS

Rat models were stratified into three groups: in vitro group (n = 20) for molecular biological assays, control group (n = 3), and ANFH group induced using lipopolysaccharide and dexamethasone (n = 3). Bone marrow-derived endothelial progenitor cells (BM-EPCs) were extracted from the rats. An RNA expression array was performed on BM-EPCs, and enriched genes were subject to pathway analysis. In vitro studies following findings of array results were also performed using the isolated BM-EPCs.

RESULTS

Significant alterations in mammalian target of rapamycin (mTOR) and HIF signaling pathways were identified in BM-EPCs of ANFH. By applying cortisol and dexamethasone to BM-EPCs, significant changes in mTOR and HIF elements were identified. The alteration of HIF pathways appeared to be downstream of mTOR signaling. Glucocorticoid receptor (GR) expression was related to glucocorticoid-dependent mRNA expression of mTOR/HIF genes. mTOR-dependent angiogenesis but not anabolism was the target of GR in ANFH. Inhibition of mTOR signaling also induced apoptosis of BM-EPCs via CHOP-dependent DR5 induction in response to GR stimulation.

CONCLUSION

Decreased mTOR signaling in response to GR stimulation leading to downregulated HIF pathway as well as increased apoptosis could be the pathophysiology.

Evaluation of bone viability in patients after girdlestone arthroplasty: comparison of bone SPECT/CT and MRI

PURPOSE

To test the diagnostic performance of bone SPECT/CT and MRI for the evaluation of bone viability in patients after girdlestone-arthroplasty with histopathology used as gold standard.

MATERIALS AND METHODS

In this cross-sectional study, patients after girdlestone-arthroplasty were imaged with single-photon-emission-computed-tomography/computed-tomography (SPECT/CT) bone-scans using 99mTc-DPD. Additionally, 1.5 T MRI was performed with turbo-inversion-recovery-magnitude (TIRM), contrast-enhanced T1-fat sat (FS) and T1-mapping. All imaging was performed within 24 h prior to revision total-hip-arthroplasty in patients with a girdlestone-arthroplasty. In each patient, four standardized bone-tissue-biopsies (14 patients) were taken intraoperatively at the remaining acetabulum superior/inferior and trochanter major/minor. Histopathological evaluation of bone samples regarding bone viability was used as gold standard.

RESULTS

A total of 56 bone-segments were analysed and classified as vital (n = 39) or nonvital (n = 17) by histopathology. Mineral/late-phase SPECT/CT showed a high sensitivity (90%) and specificity (94%) to distinguish viable and nonviable bone tissue. TIRM (sensitivity 87%, specificity 88%) and contrast-enhanced T1-FS (sensitivity 90%, specificity 88%) also achieved a high sensitivity and specificity. T1-mapping achieved the lowest values (sensitivity 82%, specificity 82%). False positive results in SPECT/CT and MRI resulted from small bone fragments close to metal artefacts.

CONCLUSIONS

Both bone SPECT/CT and MRI allow a reliable differentiation between viable and nonviable bone tissue in patients after girdlestone arthroplasty. The findings of this study could also be relevant for the evaluation of bone viability in the context of avascular bone necrosis.

A Simple Procedure for the Evaluation of Bone Vitality by Staining with a Tetrazolium Salt

Presently, no intra-operative method for a direct assessment of bone vitality exists. Therefore, we set out to test the applicability of tetrazolium-based staining on bone samples. The explanted femoral heads of 37 patients were used to obtain either cancellous bone fragments or bone slices. Samples were stained with 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (thiazolyl blue, MTT) at different times (one to twelve hours) after explantation. Staining was quantified either spectrophotometrically after extraction of the dyes or by densitometric image analysis. TTC-staining of cancellous bone fragments and bone slices, respectively, indicated the detectability of vital cells in both types of samples in a window of up to six hours after explantation. Staining intensity at later time-points was indistinguishable from the staining of untreated samples or sodium azide treated samples, which represent dead cells. In contrast, MTT-staining of bone slices revealed intense unspecific staining, which obscured the evaluation of the vitality of the samples. The lack of a detectable increase of colour intensity in TTC-stained bone samples, which were treated more than six hours after explantation, corresponds to reduced fracture healing. The described simple procedure could provide a basis for an intraoperative decision by the orthopaedic surgeon.