Orthopaedic tumors: What problems are we solving, and are universities and major medical centers doing enough?

T2-weighted MRI radiomics in high-grade intramedullary osteosarcoma: predictive accuracy in assessing histologic response to chemotherapy, overall survival, and disease-free survival

OBJECTIVE

To analyze radiomic features obtained from pre-treatment T2-weighted MRI acquisitions in patients with histologically proven intramedullary high-grade osteosarcomas and assess the accuracy of radiomic modelling as predictive biomarker of tumor necrosis following neoadjuvant chemotherapy (NAC), overall survival (OS), and disease-free survival (DFS).

MATERIALS AND METHODS

Pre-treatment MRI exams in 105 consecutive patients who underwent NAC and resection of high-grade intramedullary osteosarcoma were evaluated. Histologic necrosis following NAC, and clinical outcome-survival data was collected for each case. Radiomic features were extracted from segmentations performed by two readers, with poorly reproducible features excluded from further analysis. Cox proportional hazard model and Spearman correlation with multivariable modelling were used for assessing relationships of radiomics features with OS, DFS, and histologic tumor necrosis.

RESULTS

Study included 74 males, 31 females (mean 32.5yrs, range 15-77 years). Histologic assessment of tumor necrosis following NAC was available in 104 cases, with good response (≥ 90% necrosis) in 41, and poor response in 63. Fifty-three of 105 patients were alive at follow-up (median 40 months, range: 2-213 months). Median OS was 89 months. Excluding 14 patients with metastases at presentation, median DFS was 19 months. Eleven radiomics features were employed in final radiomics model predicting histologic tumor necrosis (mean AUC 0.708 ± 0.046). Thirteen radiomic features were used in model predicting OS (mean concordance index 0.741 ± 0.011), and 12 features retained in predicting DFS (mean concordance index 0.745 ± 0.010).

CONCLUSIONS

T2-weighted MRI radiomic models demonstrate promising results as potential prognostic biomarkers of prospective tumor response to neoadjuvant chemotherapy and prediction of clinical outcomes in conventional osteosarcoma.

Establishment of a finite element model and stress analysis of intra-articular impacted fragments in posterior malleolar fractures

Background

Intra-articular impacted fragments (IAIFs) are considered articular surface fragments resulting from impact and compressive forces. The malreduction of IAIFs in posterior malleolar fractures has been associated with talar subluxation and long-term post-traumatic arthritis. In this study, we establish IAIF defect finite element models of different sizes in posterior malleolar fractures and explored how IAIF defects predict the onset of post-traumatic arthritis.

Methods

A reliable three-dimensional finite element model of the normal ankle was established. Finite element models with different sizes of IAIF defects were created to calculate ankle joint contact stress. The finite element data were recorded and analyzed.

Results

There was a linear relationship between the size of the IAIF defect and MCS with IAIF defects in the posterolateral region. The result of Pearson linear correlation analysis was r = 0.963, P = 0.009. The regression equation was MCS = 0.087*AI + 2.951 (AI, area of IAIF) by simple linear regression analysis. When the IAIF defect was in the posteromedial region, there was also a linear relationship between the size of the IAIF defect and MCS. The result of Pearson linear correlation analysis was r = 908, P = 0.033. The regression equation was MCS = 0.065*AI + 1.841. The MCS was increased mainly in the border of the IAIF defect.

Conclusions

A small IAIF defect in the posterior malleolus will result in a high MCS, and the MCS in the posterolateral region is larger than the MCS in the posteromedial region when the size of the IAIF defect is the same. We obtain the regression equation of MCS and area of IAIF defect. This indicates that patients are more prone to post-trauma arthritis when the size of IAIF defects is more than 17.8 mm² in the posterolateral region and more than 40.9 mm² in the posteromedial region.

Trial registration Retrospectively registered.

Factors, treatments, and outcomes associated with primary soft tissue malignancies of the forearm: A series of 31 cases

Background

Primary soft tissue malignancies of the forearm constitute up to 24% of soft tissue extremity malignancies and present a difficult problem when attempting to preserve both life and forearm function. As described by Enneking, recurrence and metastasis are the two largest contributors to morbidity and mortality and therefore, the primary consideration must be to excise the entire tumor. However, since limb salvage is the preferred treatment over amputation in 95% of cases, many physicians elect to perform marginal resections over wide resections in the attempt to increase functional outcomes. Our study aimed to compare recurrence rates and forearm functional outcomes between these groups to better guide clinical decision making.

Questions/purposes

(1) What is the difference in recurrence rates between wide resection of the tumor and marginal resection? (2) Between wide and marginal resection groups, what is the functional difference as measured by MSTS functional outcome scores? The purpose of our study was to answer these two questions and better understand if marginal resection yielded better results compared to wide resection.

Patients and methods

Following IRB approval, we conducted a retrospective case series between 1999 and 2019. Included in the study were patients with a primary malignancy in the predetermined borders of the forearm with a minimum of two-year follow up post-operatively. All patients in the study were operated on by physicians in the Southern California Kaiser Permanente system. Thirty-one patients met criteria for the study. Recurrence rates and metastatic disease was determined through serial history and physical examination, with patients undergoing magnetic resonance (MRI) imaging of the affected area and computed tomography (CT) of the chest every 6 months for the first 2 years, and every 12 months for the following 3 years. MSTS scores were obtained in subsequent follow-ups following the guidelines set by the MSTS scoring system.

Results

Of the 31 patients evaluated, 4 (12.9%) had recurrence and 2 (6.5%) had signs of metastasis. Between the marginal excision and wide excision groups, all 4 recurrences happened in the marginal excision group and none occurred in the wide excision group. In addition, in the pathology report, excisions with 0.1 cm margins or less on any side had 3 instances of recurrence (31%) whereas there was only 1 recurrence (4.8%) outside of this group. MSTS scores for both wide excision and marginal excision were within 1 point with average scores being 26 and 26.9, respectively.

Conclusions

Consistent with the literature, our study found that closer surgical margins lead to higher rates of recurrence due to the increased likelihood of aberrant tumor. However, when looking at functional outcome scores, we found minimal benefit in marginal resections compared to wide resections. The lack of MSTS score difference between both groups highlighted that the perceived benefit of choosing a marginal resection over wide excision may be nominal at best. Therefore, we recommend performing an additional intraoperative resection on narrow margins to reduce the chance of recurrence. Of note, clinical discernment in the form of preserving valuable neurovascular structures such as the median nerve should still be an important consideration.

Biomarker potential of lncRNA GNAS-AS1 in osteosarcoma prognosis and effect on cellular function

BACKGROUND

Osteosarcoma (OS) is a type of bone cancer that occurs in children and adolescents at a rate of 5%. The purpose of this study is to explore the lncRNA GNAS-AS1 expression profile, prognosis significance in OS, and biological effect on OS cell function.

METHODS

One hundred eight pairs of tissues were collected, and OS cell lines were purchased. lncRNA GNAS-AS1 expression in these tissues and cells were analyzed by qRT-PCR. Clinical data were analyzed using chi-square tests, Kaplan-Meier curves (log-rank test), and Cox regression. CCK-8 and transwell assay were conducted to analyze the effect of lncRNA GNAS-AS1 on cell proliferation, invasion, and migration. The downstream miRNA was presumed.

RESULTS

The expression of lncRNA GNAS-AS1 was significantly increased in OS cells and tissues, and related to Enneking staging and distant metastasis. Patients with high lncRNA GNAS-AS1 expression represented shorter overall survival and was an independent prognostic predictor of OS. LncRNA GNAS-AS1 knockdown inhibited cell proliferation, migration, and invasion by regulated miR-490-3p partly at least.

CONCLUSIONS

LncRNA GNAS-AS1 can be used as a prognostic indicator and its inhibition suppress the development of OS, suggesting its value as novel therapeutic strategies in OS.

Clinical observation and finite element analysis of cannulated screw internal fixation in the treatment of femoral neck fracture based on different reduction quality

Objective

Femoral neck fracture is one of the most common bone types. The effect of reduction quality on hip joint function and complications after screw internal fixation is not fully understood. To investigate the clinical efficacy and mechanical mechanism of positive buttress, anatomical reduction, and negative buttress in the treatment of femoral neck fracture after cannulated screw fixation.

Methods

Retrospective analysis of patients with femoral neck fracture treated with three cannulated screws internal fixation in our hospital from January 2013 to December 2018. According to the quality of fracture reduction, the patients were divided into positive buttress group, anatomical reduction group, and negative buttress group. Basic information such as injury mechanism, time from injury to surgery, Garden classification and Pauwels classification was collected, Harris scores were performed at 3 months, 6 months, and 12 months after surgery, and postoperative complications (femoral head necrosis, femoral neck shortening, and femoral neck nonunion) were collected. At the same time, three groups of finite element models with different reduction quality were established for stress analysis, their stress clouds were observed and the average displacement and stress of the three groups of models were compared. P < 0.05 was used to represent a statistically significant difference.

Results

A total of 225 cases of unilateral femoral neck fractures were included and followed up for an average of 4.12 ± 0.69 years. There was no significant difference in age, gender, side, injury mechanism, time from injury to surgery, BMI, Garden classification, Pauwels classification, and follow-up time among the three groups (P > 0.05). However, there was significant difference in Harris score at 6 and 12 months after operation among the three groups (P < 0.05), which was higher in the positive buttress group and anatomical reduction group than in the negative buttress group. In addition, the incidence of osteonecrosis of the femoral head in the negative buttress group (32.2%) was greater than that in the anatomical reduction group (13.4%) and the positive buttress group (5.4%) (P < 0.05). In addition, the incidence of femoral neck nonunion and femoral neck shortening in the negative buttress group was also higher than that in the anatomical reduction positive buttress group (P < 0.05). The finite element results showed that the stress and fracture end displacement in the negative buttress group were greater than those in the positive buttress group (P < 0.05).

Conclusion

Both positive buttress and anatomical reduction in the treatment of femoral neck fracture with cannulated screw internal fixation can obtain better clinical effect and lower postoperative complications. Positive brace support and anatomic reduction can limit the restoration of femoral stress conduction. Therefore, it is not necessary to pursue anatomical reduction too deliberately during surgery, while negative buttress reduction should be avoided.

Correction of complex three-dimensional deformities at the proximal femur using indirect reduction with angle blade plate and patient-specific instruments: a technical note

BACKGROUND

Corrective osteotomies for complex proximal femoral deformities can be challenging; wherefore, subsidies in preoperative planning and during surgical procedures are considered helpful. Three-dimensional (3D) planning and patient-specific instruments (PSI) are already established in different orthopedic procedures. This study gives an overview on this technique at the proximal femur and proposes a new indirect reduction technique using an angle blade plate.

METHODS

Using computed tomography (CT) data, 3D models are generated serving for the preoperative 3D planning. Different guides are used for registration of the planning to the intraoperative situation and to perform the desired osteotomies with the following reduction task. A new valuable tool to perform the correction is the use of a combined osteotomy and implant-positioning guide, with indirect deformity reduction over an angle blade plate.

RESULTS

An overview of the advantages of 3D planning and the use of PSI in complex corrective osteotomies at the proximal femur is provided. Furthermore, a new technique with indirect deformity reduction over an angle blade plate is introduced.

CONCLUSION

Using 3D planning and PSI for complex corrective osteotomies at the proximal femur can be a useful tool in understanding the individual deformity and performing the aimed deformity reduction. The indirect reduction over the implant is a simple and valuable tool in achieving the desired correction, and concurrently, surgical exposure can be limited to a subvastus approach.

The study of screw placement parameters for Ogawa type I acromial fractures by 3D simulation

Background

Acromial fractures are rare and there is no consensus on fixation, but an increasing number of studies have reported using two screws to fix Ogawa type I acromial fractures. The objective of this study was to obtain the ideal length, diameter, insertion point, and angle of the screw using a novel 3D simulation.

Methods

The scapular CT data of 100 individuals were obtained to reconstruct 3D models. The transparency of the 3D model was then downgraded along the axial perspective (the view perpendicular to the cross section of the acromion axis) to find the maximum translucent area. Two virtual screws were placed at the anterior edge of the acromion until they penetrated the posterior cortical bon. The largest diameters and lengths of the screw were measured, and the direction and insertion point of the screw were observed.

Results

The mean maximum lengths of the medial and lateral screws were 43.33 ± 6.17 mm and 39.23 ± 6.01 mm, respectively. The mean maximum diameters of the medial and lateral screws were 4.71 ± 1.23 mm and 4.97 ± 1.07 mm, respectively. Differences in screw length, diameter, and insertion point between males and females were found. The differences in screw angle between sexes were not statistically significant.

Conclusions

Based on a 3D model test, we recommend the size, entry points, and angles of screws for Ogawa type I acromial fractures, providing valuable guidance for clinical work. More accurate screw parameters can be obtained preoperatively by establishing an individualized 3D model.

A guideline for screw fixation of coracoid process base fracture by 3D simulation

BACKGROUND

Fractures of the base of the coracoid process are relatively rare, but an increasing number of studies have reported using screws to fix coracoid process base fractures. This study was performed to simulate the surgical procedure and obtain the ideal diameter, length, insertion point and angle of the screw from a 3-D axial perspective in Chinese patients.

METHODS

We randomly collected right scapula computed tomography (CT) scans from 100 adults. DICOM-formatted CT scan images were imported into Mimics software. A 3D digital model of the right scapula was established. Two virtual cylinders representing two screws were placed from the top of the coracoid process to the neck of the scapula and across the base of the coracoid process to fix the base of the coracoid process. The largest secure diameters and lengths of the virtual screws were measured. The positions of the insertion points and the directions of the screws were also examined.

RESULTS

The screw insertion safe zone can exhibit an irregular fusiform shape according to the reconstructed scapula model. The mean maximum diameters of the medial and lateral screws were 7.08 ± 1.19 mm and 7.34 ± 1.11 mm, respectively. The mean maximum lengths of the medial and lateral screws were 43.11 ± 6.31 mm and 48.16 ± 6.94 mm, respectively. A screw insertion corridor with a diameter of at least 4.5 mm was found in all patients. We found sex-dependent differences in the mean maximum diameters and maximum lengths of the two screws. The positions of the two insertion points were statistically different across sexes.

CONCLUSIONS

The study provides a valuable guideline for determining the largest secure corridor for two screws in fixing a fracture at the base of the coracoid process. For ideal screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screws.

Unilateral-dominant reduction in muscle volume in female knee osteoarthritis patients: computed tomography-based analysis of bilateral sides

Background

Muscle weakness is associated with osteoarthritis pathology. A recent study demonstrated that measuring muscle volume using computed tomography (CT)-based analysis and comparing bilateral muscles in the same patient allowed for accurate evaluation of muscle volume in unilateral hip osteoarthritis (OA) patients. Here, we evaluated muscle volume using CT-based analysis and compared bilateral muscles in knee OA (KOA) patients.

Methods

CT images were obtained from 35 female radiographic KOA patients the day prior to total knee replacement surgery. Muscle volume (MV) was semi-automatically analyzed. Knee extension muscle strength (MS) was determined using a hand-held dynamometer. The severity of KOA patients’ clinical symptoms was examined using four domains of the Japanese Orthopedic Association (JOA) score. We compared the difference in MS (ΔMS) and MV (ΔMV) between the operated side (OS), which exhibited severe radiographic OA or severe pain, and the contralateral side (CS).

Results

JOA score was significantly lower in the OS than CS. MV and MS were also significantly lower in the OS than CS. There was no correlation between MV and MS or between MV and MS as a percentage of body weight on either side. However, ΔMV was positively correlated with ΔMS and pain on walking in the JOA.

Conclusions

We evaluated MV and MS using bilateral CT images of the legs of KOA patients. A reduction in MV was observed on the OS, and was correlated with a reduction in MS and pain on walking. Bilateral CT image analysis may be useful for evaluating the relationship between OA pathology and muscle atrophy.

Effect of lesser trochanter posteromedial wall defect on the stability of femoral intertrochanteric fracture using 3D simulation

BACKGROUND

This study investigated the effects of posteromedial fracture fragments on the postoperative stability of intertrochanteric fractures of the femur by analyzing the quantity and range of fragments in CT 3D reconstruction.

MATERIALS AND METHODS

Patients diagnosed with femoral lesser trochanter fractures were collected from September 2015 to February 2018. CT 3D reconstruction was applied to evaluate the quantity and extension of posteromedial fragments and the presence of isolated medial fragments. The stability of postoperative fracture was evaluated by comparing the changes of "neck-shaft angle" and "telescoping" from 1 week to 1 year after operation.

RESULTS

A total of 143 patients were finally confirmed, in which 63 patients contained isolated fragments on the medial side, and the average number of fragments in the posteromedial side was 1.93 ± 0.34, which accounted for an average of about 86.11% ± 8.20% in the whole posteromedial wall. When the number of posteromedial fragments was > 2 and the range of posteromedial fragments was > 75%, then the changes in the neck-shaft angle and "telescoping" showed statistical significance (12.27 ± 4.18 mm and 10.13 ± 6.17°, respectively), and when there were isolated medial isolated fragments, then the change in the neck-shaft angle was 10.66 ± 4.27°, showing statistical significance.

CONCLUSIONS

These findings revealed a certain correlation between the quantity and the range of posteromedial fragments and the postoperative "shortening" and "collapse" of femoral intertrochanteric fractures.

An overview of thermal necrosis: present and future

Introduction: Many orthopaedic procedures require drilling of bone, especially fracture repair cases. Bone drilling results in heat generation due to the friction between the bone and the drill bit. A high-level of heat generation kills bone cells. Bone cell death results in resorption of bone around bone screws.Methods: We searched in the literature for data on parameters that influence drilling bone and could lead to thermal necrosis. The points of view of many orthopaedists and neurosurgeons based upon on previous practices and clinical experience are presented.Results: Several potential complications that lead to thermal necrosis are discussed and highlighted.Discussion: Even in the face of growing evidence as to the negative effects of heat induction during drilling, simple and effective methods for monitoring and cooling in real-time are not in widespread usage today. For that purpose, we propose some suggestions for the future of bone drilling, taking note of recent advances in autonomous robotics, intelligent systems and computer simulation techniques.Conclusions: These advances in prevention of thermal necrosis during bone drilling surgery are expected to reduce the risk of patient injury and costs for the health service.

A review of translational medicine. The future paradigm: how can we connect the orthopedic dots better?

INTRODUCTION

Patients with complex medical and surgical problems often travel great distances to prestigious university medical centers in search of solutions and in some cases for nothing more than a diagnosis of their condition. Translational medicine (TM) is an emerging method and process of facilitating medical advances efficiently from the scientist to the clinician. Most established clinicians and those in training know very little about this new discipline. The purpose of this article is to illustrate TM in varied scientific, medical and surgical fields.

MATERIALS AND METHODS

Anecdotal events in medicine and orthopaedics based upon a practicing orthopaedic surgeon's training and clinical experience are presented.

RESULTS

TM is rapidly assuming a greater presence in the medical community. The National Institute of Health (NIH) recognizes this discipline and has funded TM projects. Numerous institutions in Europe and the USA offer advanced degrees in TM. Finally there is a European Society for Translational Medicine (EUTMS), an International Society for Translational Medicine, and an Academy of Translational Medical Professionals (ATMP).

DISCUSSION

The examples of TM presented in this article support the argument for the formation of more TM networks on the local and regional levels. The need for increased participation of researchers and clinicians requires further study to identify the economic and social impact of TM.

CONCLUSIONS

The examples of TM presented in this article support the argument for the formation of more TM networks on the local and regional levels. Financial constraints for TM can be overcome by pooling government, academic, private, and industry resources in an organized fashion with oversight by a lead TM researcher.