Comparison of radiographic appearance and bone scintigraphy in fracture nonunions

Assessment of Bone Healing: Opportunities to Improve the Standard of Care

➤ Bone healing is commonly evaluated by clinical examination and serial radiographic evaluation. Physicians should be mindful that personal and cultural differences in pain perception may affect the clinical examination. Radiographic assessment, even with the Radiographic Union Score, is qualitative, with limited interobserver agreement.➤ Physicians may use serial clinical and radiographical examinations to assess bone healing in most patients, but in ambiguous and complicated cases, they may require other methods to provide assistance in decision-making.➤ In complicated instances, clinically available biomarkers, ultrasound, and magnetic resonance imaging may determine initial callus development. Quantitative computed tomography and finite element analysis can estimate bone strength in later callus consolidation phases.➤ As a future direction, quantitative rigidity assessments for bone healing may help patients to return to function earlier by increasing a clinician's confidence in successful progressive healing.

Influence of Metal Implants on Quantitative Evaluation of Bone Single-Photon Emission Computed Tomography/Computed Tomography

When visualizing biological activity at nonunion sites by the radioisotopes, gamma rays are more attenuated if metal implants are placed in the bone. However, the effects of various implant types and their placement on gamma ray attenuation in quantitative evaluation remain unknown. To elucidate these effects, we created a phantom that simulated the nonunion of the femur in this study. The count of gamma rays was measured by single-photon emission computed tomography/computed tomography (SPECT/CT) while considering CT-based attenuation correction (CTAC), metal implant placement, type (intramedullary nail or plate), and position. The count differed significantly with and without CTAC and with and without implants (both types) under CTAC. Significantly different counts were observed between the intramedullary nail and plate placed contralaterally to the lesion (i.e., non-lesion side). No significant difference was observed between the intramedullary nail and plate on the lesion side or between plates on the non-lesion and lesion sides. The measured standardized uptake value (SUV) was closer to the true SUV with CTAC than without. Moreover, the count was higher with implants than without. However, even with implants, it was lower than the actual count, indicating the absence of overcorrection. Implant type and position do not seem to influence the count.

Wireless Measurements Using Electrical Impedance Spectroscopy to Monitor Fracture Healing

There is an unmet need for improved, clinically relevant methods to longitudinally quantify bone healing during fracture care. Here we develop a smart bone plate to wirelessly monitor healing utilizing electrical impedance spectroscopy (EIS) to provide real-time data on tissue composition within the fracture callus. To validate our technology, we created a 1-mm rabbit tibial defect and fixed the bone with a standard veterinary plate modified with a custom-designed housing that included two impedance sensors capable of wireless transmission. Impedance magnitude and phase measurements were transmitted every 48 h for up to 10 weeks. Bone healing was assessed by X-ray, µCT, and histology. Our results indicated the sensors successfully incorporated into the fracture callus and did not impede repair. Electrical impedance, resistance, and reactance increased steadily from weeks 3 to 7-corresponding to the transition from hematoma to cartilage to bone within the fracture gap-then plateaued as the bone began to consolidate. These three electrical readings significantly correlated with traditional measurements of bone healing and successfully distinguished between union and not-healed fractures, with the strongest relationship found with impedance magnitude. These results suggest that our EIS smart bone plate can provide continuous and highly sensitive quantitative tissue measurements throughout the course of fracture healing to better guide personalized clinical care.

Clinical, Histological, and Scintigraphic Comparative Study of the Use of Mandibular Bone Marrow and Peripheral Blood in Bone Neoformation

Materials and Methods

The study included 16 patients with maxillary atresia. The region was grafted with xenograft blocks associated with the following treatments: G1, the patient's peripheral blood during surgery, and G2, dripping of mandibular bone marrow blood until the xenograft was completely wet. After 7 and 14 days, scintigraphic images of the regions of interest (ROI) were taken to quantify pixels, which indicate osteogenic activity. Additionally, trephined samples obtained at the time of implant placement were stained in H&E, and newly formed bone tissue was quantified. The data were tabulated and statistically analyzed at a significance level of 5%.

Results

Scintigraphic data showed greater osteogenic activity with mandibular bone marrow blood (G2) at all times evaluated (p < 0.05). As for the histomorphometric analysis, a greater amount of bone tissue was observed in samples treated with mandibular bone marrow blood (G2) compared to peripheral blood (G1) (p < 0.05).

Conclusions

The appositional bone reconstruction technique in the block associated with mandibular bone marrow blood increased bone neoformation and osteogenic activity compared to conventional graft treatment with peripheral blood.

Quantitative bone single-photon emission computed tomography imaging for uninfected nonunion: comparison of hypertrophic nonunion and non-hypertrophic nonunion

BACKGROUND

Recently, a standardized uptake value (SUV) has been used to evaluate bone single-photon emission computed tomography (SPECT). The aim of this study was to investigate quantitative SPECT imaging of uninfected nonunion to compare hypertrophic nonunion and non-hypertrophic nonunion using volume-based parameters.

METHODS

We evaluated 23 patients with uninfected nonunion who underwent SPECT acquisition 3 h after an injection of ^99mTc-hydroxymethylene diphosphonate or ^99mTc-methylene diphosphonate from April 2014 to November 2019. We reconstructed the acquired data and performed voxel-based quantitative analysis using the GI-BONE software. Quantitative parameters, maximum SUV (SUV_max), peak SUV (SUV_peak), and mean SUV (SUV_mean) in the high and low uptake areas of nonunion were compared between hypertrophic nonunion and non-hypertrophic nonunion. The contralateral limb was used as a control, and the ratios of the quantitative parameters were calculated.

RESULTS

The values for the quantitative parameters (high uptake area/low uptake area, respectively), SUV_max control ratio (12.13 ± 4.95/6.44 ± 4.71), SUV_peak control ratio (11.65 ± 4.58/6.45 ± 4.64), and SUV_mean control ratio (11.94 ± 5.03/6.28 ± 4.95) for hypertrophic nonunion were higher than those for non-hypertrophic nonunion (7.82 ± 4.76/3.41 ± 2.09 (p = 0.065/0.12), 7.56 ± 4.51/3.61 ± 2.23 (p = 0.065/0.22), and 7.59 ± 5.18/3.05 ± 1.91 (p = 0.076/0.23)).

CONCLUSIONS

SUV_max, SUV_peak, and SUV_mean control ratios obtained from bone SPECT images can quantitatively evaluate the biological activity of nonunions and may be an effective evaluation method for treatment decisions, especially the necessity of autologous bone grafting.

Value of SPECT/CT in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures

OBJECTIVE

To evaluate the value of single-photon emission computed tomography / computed tomography (SPECT/CT) compared with planar bone scintigraphy (BS) in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures.

METHODS

Retrospective evaluation of patients with traumatic fractures and suspected delayed healing or non-union and/or persistent pain or suspected infection who had undergone planar late phase BS and SPECT/CT between 2011 and 2018. On the BS and SPECT/CT images, a necrotic fragment was considered if there was an area of absent radiotracer uptake (photopenia) related to bone at the fracture site. Histology served as a reference standard (presence or absence of necrotic bone fragments). If histology was not available, intraoperative findings and combined clinical and imaging follow-up served as reference standards.

RESULTS

In 37 consecutive patients with traumatic fractures (femur (n = 18), tibia (11), humerus (6), radius (1), jaw (1)), necrotic bone fragments were suspected in 11 fractures (29.7%) on BS and in 16 fractures (43.2%) on SPECT/CT. 35 fractures (94.6%) had metallic implants. Histology showed necrotic fragments in 10/11 (90.9%) patients. For the detection of necrotic bone fragments, SPECT/CT showed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 95%, 94%, 100%, and 97%, respectively, and BS 67%, 95%, 91%, 81%, and 83%, respectively. SPECT/CT significantly outperformed BS with better area under curve (AUC) for SPECT/CT (0.9773) compared to planar imaging (0.8106) (p-value < 0.01).

CONCLUSIONS

SPECT/CT is an accurate tool in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic bone fractures and is superior to conventional planar BS.

ADVANCES IN KNOWLEDGE

SPECT/CT is accurate and superior to planar BS in identification of necrotic bone fragments, responsible for delayed bone healing/non-union after fractures.

Surgically Treated Nonunion following Ischial Tuberosity Avulsion Fracture of a 14-Year-Old Athlete

A 14-year-old girl experienced acute left buttock pain during a sprint. At the local hospital, she was diagnosed with an avulsion fracture of the left ischial tuberosity. She was kept for observation for about 10 months; however, the buttock pain persisted, and the bone fragments did not unite. She was referred to our hospital approximately 11 months after the injury. Plain radiography revealed an increased transposition of the bone fragment, from 12 mm immediately after the injury to 23 mm. Twelve months after the injury, she underwent osteosynthesis using two cannulated cancellous screws and three suture anchors. Following postoperative rehabilitation, the power in her left hamstring recovered, and she was able to run at full speed and returned to athletics 9 months after the surgery. The operative indications for avulsion fractures of the ischial tuberosity are unclear. Careful follow-up is required as the rate of nonunion after conservative treatment tends to be high. This needs to be identified in order to provide timely treatment that allows for early return to sport. Although she had significant chronic pain and muscle weakness, the surgery successfully treated the fracture, and her muscle power recovered, leading to her return to sports.

Minimally invasive plate osteosynthesis for humeral shaft nonunion: A report of two cases

Introduction

We treated two cases of humeral shaft nonunion by minimally invasive plate osteosynthesis (MIPO) without autogenous bone grafting.

Presntation of case

Case 1: An osteosynthesis with intramedullary nailing (IMN) was performed on a 17-year-old female for a humeral shaft fracture at another hospital; however, bony union was not obtained. We removed the nail and screws, then performed MIPO without autogenous bone grafting. At the final follow-up of 4 years after the surgery, she had obtained full range of motion.Case 2: Osteosynthesis with Rush pins had been performed in a 73-year-old female for a humeral shaft fracture at another hospital. Five months later, a revision surgery using IMN was performed at the same hospital; however, this led to nonunion. We removed the IMN and performed MIPO without autogenous bone grafting. At the final follow-up 2 years after surgery, she had obtained full range of motion.

Discussion

The cause of nonunion is the lack of mechanical instability and/or biological activity. In these cases, from the findings of radiography and bone scintigraphy, mechanical instability was thought to be the primary cause; therefore, in order to enhance stability, we used a locking plate. Because we can see that these cases are biologically active, we decided not to use bone grafting. Both our cases successfully achieved bony union and excellent functional recovery using this method.

Conclusion

We performed MIPO without exposure of the nonunion site and autogenous bone grafting in two cases of humeral shaft nonunion, and obtained successful clinical outcomes.

Radiologic evaluation of fracture healing

While assessment of fracture healing is a common task for both orthopedic surgeons and radiologists, it remains challenging due to a lack of consensus on imaging and clinical criteria as well as the lack of a true gold standard. Further complicating this evaluation are the wide variations between patients, specific fracture sites, and fracture patterns. Research into the mechanical properties of bone and the process of bone healing has helped to guide the evaluation of fracture union. Development of standardized scoring systems and identification of specific radiologic signs have further clarified the radiologist's role in this process. This article reviews these scoring systems and signs with regard to the biomechanical basis of fracture healing. We present the utility and limitations of current techniques used to assess fracture union as well as newer methods and potential future directions for this field.

Do Systemic Factors Influence the Fate of Nonunions to Become Atrophic? A Retrospective Analysis of 162 Cases

INTRODUCTION

Nonunions are a challenge for orthopedic surgeons. In hypertrophic nonunions, improvement of mechanical stability usually is the satisfactory treatment, whereas in atrophic nonunions improvement of the biological environment is most important. However, scientific evidence revealed that "avital" nonunions are not avascular and fibrous tissue contains cells with osteogenic potential. To find out if systemic factors suppress this intrinsic potential in atrophic nonunions, this study compares characteristics of hypertrophic with atrophic nonunion patients.

METHODS

We analyzed medical records of 162 surgically treated patients suffering from aseptic long bone nonunions. Atrophic and hypertrophic nonunions were distinguished by absence or presence of callus and calcification in the fracture gap. Mechanical implant loosening and patient characteristics such as age, gender, and body mass index were assessed. Fracture classification according to AO/OTA, open and closed fractures, and osteosynthesis were recorded. In addition, comorbidities and allergies between both groups were compared.

RESULTS

A higher number of hypertrophic nonunion patients were male with often allergies. Hypertrophic nonunion occurred more often after intramedullary nailing compared to atrophic nonunions. Atrophic nonunion patients being nonallergic were significantly older than nonallergic patients suffering from hypertrophic nonunions. In both atrophic and hypertrophic nonunion patients, age was lower in patients with accompanying injuries compared with age of patients with isolated fractures.

CONCLUSION

Systemic factors influence development of nonunion types. In nonallergic patients, atrophic nonunions occur more often in the elderly. This manuscript is a first step to identify different factors which might influence the nature of nonunion. To enable nonunion treatment which is tailored to individual patient characteristics, further prospective studies with more sophisticated research methods are necessary.

Bone Scintigraphy: A Review of Technical Aspects and Applications in Orthopedic Surgery

Due to its high sensitivity, low cost, accessibility, and ease of use, bone scintigraphy is used in orthopedic surgery for the diagnosis and management of varied pathology. It is commonly used for insufficiency fractures, metastatic neoplasia, staging and surveillance of sarcoma, and nonaccidental trauma. It augments diagnoses, including stress or occult fractures, musculoskeletal neoplasia or infection, and chronic regional pain syndrome, in patients presenting with normal results on radiographs. Bone scan images are resistant to metal-based implant artifact, allowing effective evaluation of failed total joint prostheses. Bone scintigraphy remains an underused tool in the evaluation and management of orthopedic patients. [Orthopedics. 2019; 42(1):e14-e24.].

Diagnosis and management of long-bone nonunions: a nationwide survey

Purpose

There is variability among surgeons on definitions regarding the degree of bone healing of long-bone fractures. A lack of consensus may negatively affect communication between surgeons, and lead to unintended and unwanted variability in treatment of patients suffering from abnormal healing of long-bone fractures. We aimed to identify differences between surgeons regarding their views on the degree of union of long-bone fractures.

Methods

We performed a survey among 114 surgeons who worked at 11 level I trauma centers and 68 level II/III hospitals in the Netherlands. We asked them to represent their institutional colleagues and answer questions regarding their views on the definition, factors influencing bone healing, clinical practice, views on scientific evidence, and the use or need of guidelines for non-union of long-bone fractures. A total of 26 trauma surgeons and 37 orthopedic surgeons responded (59%).

Results

Compared to trauma surgeons, more orthopedic surgeons maintain 6 months as the timeframe for classifying a fracture without healing tendencies as a non-union fracture (50 vs 70%; P = 0.019). Compared to orthopedic surgeons, trauma surgeons use the bone scan (46 vs 19%; P = 0.027) and the PET scan (50 vs 5.4%; P < 0.001) more often, and consider medication use to be a factor influencing bone healing more often (92 vs 69%; P = 0.040). Furthermore, they utilize bone marrow aspiration (35 vs 11%; P = 0.029), reaming of long bones (96 vs 70%; P = 0.010), synthetic bone substitutes (31 vs 5.4%; P = 0.012), bone morphogenetic proteins (58 vs 16%; P = 0.001), and the Diamond concept (92 vs 8.1%) more often as treatment modalities for non-union of long-bone fractures. Surgeons agreed on that intramedullary nail osteosynthesis was the treatment option supported by the highest level of evidence. 80% of the respondents feel a need for a clinical guideline on the management of long-bone non-union.

Conclusion

There is no consensus among surgeons on the definition, factors influencing healing, clinical practice, and scientific evidence regarding non-union of long-bone fractures. The vast majority of surgeons believe that their practice would benefit from (inter)national guidelines on this topic, and efforts should be made to reduce surgeon-to-surgeon variability in treatment recommendations and facilitate more homogenous scientific research on non-union of long-bone fractures.

Level of evidence

Level V.

Bone Scan in Detection of Biological Activity in Nonhypertrophic Fracture Nonunion

Biological activity of the fracture site is very important factor in treatment planning of fracture nonunion. If no biological activity is detected, then an autologous bone graft can be supplemented or osteogenic supplementations, such as bone morphogenetic protein is given. If biological activity is present, then secure fixation is sufficient to achieve bony union. Biological activity of nonunions is usually assessed by conventional radiographs. The presence of callus formation is usually assessed as the presence of biological activity. However, high number of radiologically nonhypertrophic nonunion demonstrates intense, uniform tracer uptake on bone scan, a sign of biological activity. Poor or absent callus visualization on radiographs does not always mean a lack of biological activity and it underestimates it. Uptake in bone scintigraphy reflects blood flow and new bone formation and being functional imaging technique, it is more suitable for assessing biological activity.

Treatment of Nonunions After Malleolar Fractures

Ankle fracture nonunion is a rare occurrence following closed or operative intervention. When it does occur, patients can experience debilitating symptoms that limit daily function. Malleolar nonunion can be caused by patient factors, such as smoking, malnutrition, or vascular insufficiency. Surgeon factors, such as insufficient or inappropriate operative fixation, also play a role. Several adjuncts, such as bone grafting, bone morphogenic protein, and bone stimulation, are useful in treating nonunions. Through a multimodal approach, malleolar nonunions are reliably treated with operative fixation leading to good patient outcomes with minimal complications.