Bone Material Strength Index as Measured by Impact Microindentation is Low in Patients with Primary Hyperparathyroidism.

CONTEXT: In primary hyperparathyroidism (PHPT) bone mineral density (BMD) is typically decreased in cortical bone and relatively preserved in trabecular bone. An increased fracture rate is observed however not only at peripheral sites but also at the spine, and fractures occur at higher BMD values than expected. We hypothesized that components of bone quality other than BMD are affected in PHPT as well. OBJECTIVE: To evaluate bone material properties using impact microindentation (IMI) in PHPT patients. METHODS: In this cross-sectional study, the Bone Material Strength index (BMSi) was measured by IMI at the midshaft of the tibia in 37 patients with PHPT (28 women), 11 of whom had prevalent fragility fractures, and 37 euparathyroid controls (28 women) matched for age, gender, and fragility fracture status. RESULTS: Mean age of PHPT patients and controls was 61.8 ±â€…13.3 and 61.0 ±â€…11.8 years, respectively, P = .77. Calcium and PTH levels were significantly higher in PHPT patients but BMD at the lumbar spine (0.92 ±â€…0.15 vs 0.89 ±â€…0.11, P = .37) and the femoral neck (0.70 ±â€…0.11 vs 0.67 ±â€…0.07, P = .15) were comparable between groups. BMSi however was significantly lower in PHPT patients than in controls (78.2 ±â€…5.7 vs 82.8 ±â€…4.5, P < .001). In addition, BMSi was significantly lower in 11 PHPT patients with fragility fractures than in the 26 PHPT patients without fragility fractures (74.7 ±â€…6.0 vs 79.6 ±â€…5.0, P = .015). CONCLUSION: Our data indicate that bone material properties are altered in PHPT patients and most affected in those with prevalent fractures. IMI might be a valuable additional tool in the evaluation of bone fragility in patients with PHPT.

Virtual mechanical tests out-perform morphometric measures for assessment of mechanical stability of fracture healing in vivo.

Finite element analysis with models derived from computed tomography (CT) scans is potentially powerful as a translational research tool because it can achieve what animal studies and cadaver biomechanics cannot-low-risk, noninvasive, objective assessment of outcomes in living humans who have actually experienced the injury, or treatment being studied. The purpose of this study was to assess the validity of CT-based virtual mechanical testing with respect to physical biomechanical tests in a large animal model. Three different tibial osteotomy models were performed on 44 sheep. Data from 33 operated limbs and 20 intact limbs was retrospectively analyzed. Radiographic union scoring was performed on the operated limbs and physical torsional tests were performed on all limbs. Morphometric measures and finite element models were developed from CT scans and virtual torsional tests were performed to assess healing with four material assignment techniques. In correlation analysis, morphometric measures and radiographic scores were unreliable predictors of biomechanical rigidity, while the virtual torsion test results were strongly and significantly correlated with measured biomechanical test data, with high absolute agreement. Overall, the results validated the use of virtual mechanical testing as a reliable in vivo assessment of structural bone healing. This method is readily translatable to clinical evaluation for noninvasive assessment of the healing progress of fractures with minimal risk. Clinical significance: virtual mechanical testing can be used to reliably and noninvasively assess the rigidity of a healing fracture using clinical-resolution CT scans and that this measure is superior to morphometric and radiographic measures.

Smoking, Obesity, and Disability Benefits or Litigation Are Not Associated with Clinically Important Reductions in Physical Functioning After Intramedullary Nailing of Tibial Shaft Fractures: A Retrospective Cohort Study.

BACKGROUND: Forty percent of long bone fractures involve the tibia. These fractures are associated with prolonged recovery and may adversely affect patients' long-term physical functioning; however, there is limited evidence to inform what factors influence functional recovery in this patient population. QUESTION/PURPOSE: In a secondary analysis of a previous randomized trial, we asked: What fracture-related, demographic, social, or rehabilitative factors were associated with physical function 1 year after reamed intramedullary nailing of open or closed tibial shaft fractures? METHODS: This is a secondary (retrospective) analysis of a prior randomized trial (Trial to Re-evaluate Ultrasound in the Treatment of Tibial Fractures; TRUST trial). In the TRUST trial, 501 patients with unilateral open or closed tibial shaft fractures were randomized to self-administer daily low-intensity pulsed ultrasound or use a sham device, of which 15% (73 of 501) were not followed for 1 year due to early study termination as a result of futility (no difference between active and sham interventions). Of the remaining patients, 70% (299 of 428) provided full data. All fractures were fixed using reamed (298 of 299) or unreamed (1 of 299) intramedullary nailing. Thus, we excluded the sole fracture fixed using unreamed intramedullary nailing. The co-primary study outcomes of the TRUST trial were time to radiographic healing and SF-36 physical component summary (SF-36 PCS) scores at 1-year. SF-36 PCS scores range from 0 to 100, with higher scores being better, and the minimum clinically important difference (MCID) is 5 points. In this secondary analysis, based on clinical and biological rationale, we selected factors that may be associated with physical functioning as measured by SF-36 PCS scores. All selected factors were inserted simultaneously into a multivariate linear regression analysis. RESULTS: After adjusting for potentially confounding factors, such as age, gender, and injury severity, we found that no factor showed an association that exceeded the MCID for physical functioning 1 year after intramedullary nailing for tibial shaft fractures. The independent variables associated with lower physical functioning were current smoking status (mean difference -3.0 [95% confidence interval -5 to -0.5]; p = 0.02), BMI > 30 kg/m2 (mean difference -3.0 [95% CI -5.0 to -0.3]; p = 0.03), and receipt of disability benefits or involvement in litigation, or plans to be (mean difference -3.0 [95% CI -5.0 to -1]; p = 0.007). Patients who were employed (mean difference 4.6 [95% CI 2.0 to 7]; p < 0.001) and those who were advised by their surgeon to partially or fully bear weight postoperatively (mean difference 2.0 [95% CI 0.1 to 4.0]; p = 0.04) were associated with higher physical functioning. Age, gender, fracture severity, and receipt of early physical therapy were not associated with physical functioning at 1-year following surgical fixation. CONCLUSION: Among patients with tibial fractures, none of the factors we analyzed, including smoking status, receipt of disability benefits or involvement in litigation, or BMI, showed an association with physical functioning that exceeded the MCID. LEVEL OF EVIDENCE: Level III, therapeutic study.

Assessment of body balance of patients treated with the Ilizarov method for tibial nonunion.

PURPOSE: The biomechanics of the musculoskeletal system in patients after tibial nonunion treatment using the Ilizarov method have not yet been fully explored. From the orthopaedic and patient point of view, after the treatment, an assessment should be carried out of the biomechanics of the musculoskeletal system. The aim of this study was to assess the body balance of patients treated with the Ilizarov method for tibial nonunion. METHODS: The research group included 24 individuals with a mean age of 55 years, who were treated for aseptic tibial nonunion with the Ilizarov method. The control group was matched to the study group in terms of gender and age, and consisted of 32 subjects with a mean age of 50.5 years and no significant medical history. This study evaluated the balance of patients with the use of pedobarography. RESULTS: In the control group, a statistically significantly shorter path of centre of gravity was observed. There were no statistical differences between the study and control groups for the field area of the centre of gravity. There were no statistical differences between the study and control groups for the minor axis length or major axis length of the centre of gravity. There was a relationship between the centre of pressure path length and the age of the participants in both the control group and the study group. CONCLUSIONS: Treatment of patients with tibial nonunion with the Ilizarov fixator achieves similar balance to healthy volunteers. In the pedobarographic evaluation, patients treated for tibial nonunion using the Ilizarov method had similar statics of the musculoskeletal system to healthy volunteers.

Routine postoperative radiographs after tibia plateau fixation have minimal impact on patient care.

INTRODUCTION: Common practice in orthopedic surgery is to obtain postoperative radiographs to evaluate for healing or complications. Images obtained in the post-anesthesia care unit (PACU) have not been shown to positively impact patient care. This study plans to evaluate the clinical utility and cost-effectiveness of PACU postoperative radiographs following tibial plateau open reduction and internal fixation (ORIF). METHODS: Data from 211 patients who underwent a tibial plateau ORIF over a 5-year period at a single institution were retrospectively reviewed to determine if a patient received a postoperative radiograph in the PACU. Radiograph and clinical notes were reviewed to determine if postoperative radiograph resulted in management changes. Radiograph charges were calculated using CPT codes. RESULTS: A total of 142 of 211 patients (67.3%) who underwent tibial plateau ORIF received a postoperative radiograph while in the PACU. The majority of the radiographs had normal findings (88.7%). Of the 142 patients with postoperative imaging, subsequent management changes occurred for only one patient (0.7%). In this case, an incidental foot fracture was found which resulted in further CT imaging to assess the fracture. Other abnormal radiograph readings (11.3%) were generally due to incidental, chronic findings that did not require management changes. The average postoperative radiograph cost was $433.55 per patient, totaling $91,480 for 142 patients over a 5-year period. CONCLUSIONS: Routine postoperative radiographs following tibial plateau ORIF resulted in minimal management change patients in this series. The substantial cost of postoperative radiographs yielding little clinical utility suggests the use of routine PACU imaging following tibial plateau ORIF should be discontinued. Imaging would only be indicated in situations where intraoperative complications are suspected, thus reducing unnecessary imaging and patient cost.

A practical, quantitative, fracture healing endpoint assessment criterion for tibial fractures treated with external fixation.

There is a need for a quick, simple, repeatable, but quantifiable assessment tool to determine the fracture healing endpoint of tibial fractures that does not rely on the use of X-rays or on un-measured manipulation. This article presents an argument to support a 'maximum of 1° bending' criterion. The criterion was established from an examination of patient fracture stiffness profiles and following observations of stiffness measurements made in clinics. A proprietary mono-lateral external fixator was used to test the criterion. Sixty subjects had their fracture healing endpoint assessed using this criterion compared with the 15 N m/deg in two planes criterion, and it was deemed to be successful. The method of assessment for both mono-lateral and frame fixation (Ilizarov) is demonstrated.

Bilateral Low-Dose Computed Tomography Assessment for Post-Operative Rotational Malalignment After Intramedullary Nailing for Tibial Shaft Fractures: Reliability of a Practical Imaging Technique.

INTRODUCTION: The purpose of this study is to evaluate the intra- and inter-observer reliability of low-dose protocolled bilateral postoperative Computed Tomography (CT)-assessment of rotational malalignment after intramedullary nailing (IMN) of tibial shaft fractures. MATERIALS AND METHODS: 156 patients were prospectively included with tibial shaft fractures that were treated with IMN in a Level-I Trauma Centre. All patients underwent post-operative bilateral low-dose CT-assessment (effective dose of 0.03784 - 0.05768 mGy) as per hospital protocol. Four observers performed the validated reproducible measurements of tibial torsion in degrees, based on standardized techniques. The Intra-Class Coefficient (ICC) was calculated to evaluate intra- and inter-observer reliability. The intra- and inter-observer reliability was categorized according to Landis and Koch. RESULTS: Intra-observer reliability for quantification of rotational malalignment on post-operative CT after IMN of tibial shaft fractures was excellent with 0.95 (95% CI = 0.92-0.97). The overall inter-observer reliability was 0.90 (95% CI = 0.87-0.92), also excellent according Landis and Koch. CONCLUSION: Firstly, bilateral post-operative low-dose -similar radiation exposure as plain chest radiographs- CT assessment of tibial rotational alignment is a reliable diagnostic imaging modality to assess rotational malalignment in patients following IMN of tibial shaft fractures and it allows for early revision surgery. Secondly, it may contribute to our understanding of the incidence-, predictors- and clinical relevance of post-operative tibial rotational malalignment in patients treated with IMN for a tibial shaft fracture, and facilitates future studies on this topic.

Functional assessment of transplantar nailing for ankle fracture in the elderly: 48 weeks' prospective follow-up of 14 patients.

INTRODUCTION: Retrograde transplantar intramedullary nailing (TIMN) is a recently described option for ankle fracture in elderly patients with multiple comorbidity contraindicating classical internal fixation. The main objective of the present study was to assess mobility after TIMN for ankle fracture in the elderly. The secondary objective was to assess complications. HYPOTHESIS: Retrograde TIMN provides reliable fixation of ankle fracture in the elderly, enabling early resumption of walking. MATERIAL AND METHODS: Fourteen patients, with a mean age of 79.6years (range: 65-99years), with fracture of the ankle or tibial pilon treated by retrograde TIMN, were prospectively included over a 1-year period (2014-2016). Full weight-bearing with walking cast boot was authorized as of day 1. Mobility was assessed on Parker score in consultation at 6, 12, 24 and 48 weeks. RESULTS: Ten patients were followed up. Mean Parker score was 3.6 (range: 1-5) preoperatively, and 2.4 (range: 1-5) and 2.7 (range: 1-5) at 24 and 48 weeks, respectively: i.e., not significantly different from preoperative values (p=0.057 and p=0.054, respectively). There were no decubitus-related complications. Two patients (20%) showed other complications, including 1 deep infection requiring material ablation. Consolidation was systematic, without hindfoot malunion. DISCUSSION: Retrograde TIMN appeared to be a useful option for ankle fracture in elderly patients for whom classical internal fixation was contraindicated. It allowed immediate resumption of weight-bearing and early rehabilitation, with no increased morbidity or mortality. LEVEL OF EVIDENCE: IV.

Metaphyseal locking plate as an external fixator for open tibial fracture: Clinical outcomes and biomechanical assessment.

OBJECTIVE: This study aimed to evaluate the outcome of using a metaphyseal locking plate as a definitive external fixator for treating open tibial fractures based on biomechanical experiments and analysis of clinical results. METHODS: A metaphyseal locking plate was used as an external fixator in 54 open tibial fractures in 52 patients. The mean follow-up was 38 months (range, 20-52 months). Moreover, static axial compression and torsional tests were performed to evaluate the strength of the fixation techniques. RESULTS: The average fracture healing time was 34.5 weeks (range, 12-78 weeks). At 4 weeks postoperatively and at the final follow-up, the average Hospital for Special Surgery knee score was 85 (range, 81-100) and 94 (range, 88-100), respectively, and the American Orthopaedic Foot and Ankle Society score was 88 (range, 80-100) and 96 (range, 90-100), respectively. Based on the static test result, the axial stiffness was significantly different among groups (p=0.002), whereas the torsional stiffness showed no significant difference (p=0.068). CONCLUSIONS: Clinical outcomes show that the use of locking plate as a definitive external fixator is an alternative choice for tibial fractures after obtaining appropriate fracture reduction. However, external locked plating constructs were not as strong as standard locked plating constructs. Therefore, the use of external locked plating constructs as a definitive treatment warrants further biomechanical study for construct strength improvement.

Objective Metric of Energy Absorbed in Tibial Plateau Fractures Corresponds Well to Clinician Assessment of Fracture Severity.

OBJECTIVES: Determine the agreement between subjective assessments of fracture severity and an objective computed tomography (CT)-based metric of fracture energy in tibial plateau fractures. METHODS: Six fellowship-trained orthopaedic trauma surgeons independently rank-ordered 20 tibial plateau fractures in terms of severity based on anteroposterior and lateral knee radiographs. A CT-based image analysis methodology was used to quantify the fracture energy, and agreement between the surgeons' severity rankings and the fracture energy metric was tested by computing their concordance, a statistical measure that estimates the probability that any 2 cases would be ranked with the same ordering by 2 different raters or methods. RESULTS: Concordance between the 6 orthopaedic surgeons ranged from 82% to 93%, and concordance between surgeon severity rankings and the computed fracture energy ranged from 73% to 78%. CONCLUSIONS: There is a high level of agreement between experienced surgeons in their assessments of tibial plateau fracture severity, and a slightly lower agreement between the surgeon assessments and an objective CT-based metric of fracture energy. Taken together, these results suggest that experienced surgeons share a similar understanding of what makes a tibial plateau fracture more or less severe, and an objective CT-based metric of fracture energy captures much but not all of that information. Further research is ongoing to characterize the relationship between surgeon assessments of severity, fracture energy, and the eventual clinical outcomes for patients with fractures of the tibial plateau.

Multi-Level Assessment of Fracture Calluses in Rats Subjected to Low-Magnitude High-Frequency Vibration with Different Rest Periods.

The aim of this study was to investigate the influences of low-magnitude high-frequency vibration (LMHFV) with different rest period regimes (vibrational loading per day [with or without the loading divided into bouts]; or vibrational loading for 7 day followed by 7 day rest [with or without the loading divided into bouts]) on bone healing at multi-levels. Transverse fractures of rat bilateral tibias were established using a Kirschner wire inserted for fixation. The animals were randomly assigned to five groups (n = 7 for each group): four for vibrational groups by LMHFV with different rest period regimes and one for fractured model without mechanical loading. The macromechanical properties of the fractured tibias and the nanomechanical properties of the calluses were investigated through three-point bending and nanoindentation tests, respectively. Atomic force microscopy (AFM) was performed to analyze the nanostructure of the calluses. Micro-computed tomography (micro-CT) scanning was conducted to evaluate the microarchitecture of the calluses. The serum concentration of osteocalcin (OG) and tartrate-resistant acid phosphatase 5b (TRAP5b) were measured to assess the bone formation and resorption rates, respectively. Significantly higher values of failure load and elastic modulus were observed in DL (vibrational loading for 15 min per day) and DLR (vibrational loading per day in which three bouts of 5 min of vibration were separated by 4 h) than FBC (fractured model without mechanical loading) at macro-level (P < 0.05). The results of nanoindentation test showed the highest values of indentation modulus and hardness in DLR (significantly higher than FBC; P < 0.05); besides, higher value of hardness was also observed in DL (significantly higher than FBC; P < 0.05). Though AFM imaging showed no significant differences in grain sizes between the vibrational groups and FBC, roughness of DLR showed the highest value, i.e. it was significantly higher than that in FBC (P < 0.05). For microarchitectural parameters obtained from micro-CT imaging, tissue mineral density (TMD) of DLR and VL7 (vibrational loading for 7 day followed by a 7-day rest, 15 min per day during vibrational periods) were significantly higher than that in FBC (P < 0.05), but no significant differences in other parameters were observed between vibrational groups and FBC. There were no significant differences of OG between vibrational groups and FBC; however, FBC showed significantly higher TRAP5b concentration than all vibrational groups (P < 0.05). The results show that LMHFV with different rest period regimes not only altered the macro- and nano-level bone mechanical properties but also influenced the TMD of calluses and nano-level spatial arrangement (roughness) significantly. The most significant effect of LMHFV with different rest period regimes was observed in DLR, which indicated that both osteogenic accumulation and cellular resensitization can be satisfied under this regimen. Hence, the DLR group demonstrated a great potential in clinical applications.

Biomechanical assessment and clinical analysis of different intramedullary nailing systems for oblique fractures.

The aim of this study is to evaluate the fracture union or non-union for a specific patient that presented oblique fractures in tibia and fibula, using a mechanistic-based bone healing model. Normally, this kind of fractures can be treated through an intramedullary nail using two possible configurations that depends on the mechanical stabilisation: static and dynamic. Both cases are simulated under different fracture geometries in order to understand the effect of the mechanical stabilisation on the fracture healing outcome. The results of both simulations are in good agreement with previous clinical experience. From the results, it is demonstrated that the dynamization of the fracture improves healing in comparison with a static or rigid fixation of the fracture. This work shows the versatility and potential of a mechanistic-based bone healing model to predict the final outcome (union, non-union, delayed union) of realistic 3D fractures where even more than one bone is involved.

Assessment of the efficacy of MRI for detection of changes in bone morphology in a mouse model of bone injury.

PURPOSE: To determine whether magnetic resonance imaging (MRI) could be used to track changes in skeletal morphology during bone healing using high-resolution micro-computed tomography (µCT) as a standard. We used a mouse model of bone injury to compare µCT with MRI. MATERIALS AND METHODS: Surgery was performed to induce a burr hole fracture in the mouse tibia. A selection of biomaterials was immediately implanted into the fractures. First we optimized the imaging sequences by testing different MRI pulse sequences. Then changes in bone morphology over the course of fracture repair were assessed using in vivo MRI and µCT. Histology was performed to validate the imaging outcomes. RESULTS: The rapid acquisition with relaxation enhancement (RARE) sequence provided sufficient contrast between bone and the surrounding tissues to clearly reveal the fracture. It allowed detection of the fracture clearly 1 and 14 days postsurgery and revealed soft tissue changes that were not clear on µCT. In MRI and µCT the fracture was seen at day 1 and partial healing was detected at day 14. CONCLUSION: The RARE sequence was the most suitable for MRI bone imaging. It enabled the detection of hard and even soft tissue changes. These findings suggest that MRI could be an effective imaging modality for assessing changes in bone morphology and pathobiology.

Psychometric analysis of measuring functional outcomes in tibial plateau fractures using the Short Form 36 (SF-36), Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires.

Patients participating in a modern prospective orthopaedic trauma database may be asked to complete many functional outcome measures, adding to the burden of study participation. This prospective study assessed the utility and responsiveness of the generic Short Form 36 (SF-36) and the disease specific Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires in 55 patients treated operatively for tibial plateau fractures with the goal of determining if there was clear benefit of using multiple measures in a lower extremity peri-articular fracture population. There was very good correlation between all three scores at 6 and 12 months, indicating they are measuring similar factors. Responsiveness was assessed using the standard response mean (SRM), proportion of patients attaining the minimal clinically important difference (MCID) between 6 and 12 months, and floor and ceiling effects. The SRM for the SF-36 was statistically higher than the SRM for the SMFA or the WOMAC. Significantly more patients were found to have a MCID between 6 and 12 months post-surgery based on the SF-36 than the other two functional scores. There was no floor effect found on any of the 3 functional scores evaluated; however, a significant ceiling effect was noted with the WOMAC but not with the SF-36 or the SMFA. These results, along with the usefulness of the SF-36 for comparing disease burden across populations, favour the SF-36 as the instrument of choice in assessing functional outcome in patients with tibial plateau fractures.

A comparison of stereology, structural rigidity and a novel 3D failure surface analysis method in the assessment of torsional strength and stiffness in a mouse tibia fracture model.

In attempting to develop non-invasive image based measures for the determination of the biomechanical integrity of healing fractures, traditional µCT based measurements have been limited. This study presents the development and evaluation of a tool for assessment of fracture callus mechanical properties through determination of the geometric characteristics of the fracture callus, specifically along the surface of failure identified during destructive mechanical testing. Fractures were created in tibias of ten male mice and subjected to µCT imaging and biomechanical torsion testing. Failure surface analysis, along with previously described image based measures was calculated using the µCT image data, and correlated with mechanical strength and stiffness. Three-dimensional measures along the surface of failure, specifically the surface area and torsional rigidity of bone, were shown to be significantly correlating with mechanical strength and stiffness. It was also shown that surface area of bone along the failure surface exhibits stronger correlations with both strength and stiffness than measures of average and minimum torsional rigidity of the entire callus. Failure surfaces observed in this study were generally oriented at 45° to the long axis of the bone, and were not contained exclusively within the callus. This work represents a proof of concept study, and shows the potential utility of failure surface analysis in the assessment of fracture callus stability.

Cone beam CT in assessment of tibial bone defect healing: an animal study.

RATIONALE AND OBJECTIVES: To evaluate cone beam computed tomography (CBCT) for monitoring of tibial bone defect healing in comparison to histopathological findings. MATERIALS AND METHODS: Circumscribed tibial bone defects were created in 16 mini-pigs and imaging of the tibia was performed on day 42 using a modern CBCT scanner with flat panel detector (PaX-Duo3D, Vatech, Korea). The extent of osseous consolidation including remaining calcium phosphate granules was measured quantitatively by a CBCT volumetry tool using commercially available software (Osirix Imaging software, Pixmeo, Geneva, Switzerland). Volumes of the entire defect (including all pixels), areas of osseous consolidation (density values >2350) and nonmineralized areas (density values <2350) of the defect were determined. The extent of bone regeneration was determined and correlated with the histomorphometrical reference standard. Independently, a visual semiquantitative CBCT-score was applied (4-point scale) to assess bone defect healing. RESULTS: The extent of osseous consolidation in CBCT volumetry ranged from 14% to 92% (mean, 63.4 ± 17.6%). There was a significant positive correlation between histologically visible newly formed bone and the extent of bone regeneration on CBCT volumetry (r = 0.74-0.79, P < .001). The visual score matched with the volumetric results in 75% of the cases. CONCLUSION: CBCT volumetry allows for reliable, noninvasive quantitative monitoring of bone defect healing and correlates significantly with histological findings. CBCT is a promising technique for imaging of peripheral bones suggesting further evaluation in clinical trials.

Quantitative assessment of bone defect healing by multidetector CT in a pig model.

OBJECTIVE: To evaluate multidetector CT volumetry in the assessment of bone defect healing in comparison to histopathological findings in an animal model. MATERIALS AND METHODS: In 16 mini-pigs, a circumscribed tibial bone defect was created. Multidetector CT (MDCT) of the tibia was performed on a 64-row scanner 42 days after the operation. The extent of bone healing was estimated quantitatively by MDCT volumetry using a commercially available software programme (syngo Volume, Siemens, Germany).The volume of the entire defect (including all pixels from -100 to 3,000 HU), the nonconsolidated areas (-100 to 500 HU), and areas of osseous consolidation (500 to 3,000 HU) were assessed and the extent of consolidation was calculated. Histomorphometry served as the reference standard. RESULTS: The extent of osseous consolidation in MDCT volumetry ranged from 19 to 92% (mean 65.4 ± 18.5%). There was a significant correlation between histologically visible newly formed bone and the extent of osseous consolidation on MDCT volumetry (r = 0.82, P < 0.0001). A significant negative correlation was detected between osseous consolidation on MDCT and histological areas of persisting defect (r = -0.9, P < 0.0001). CONCLUSION: MDCT volumetry is a promising tool for noninvasive monitoring of bone healing, showing excellent correlation with histomorphometry.

Use of both Short Musculoskeletal Function Assessment questionnaire and Short Form-36 among tibial-fracture patients was redundant.

OBJECTIVE: To compare the Short Musculoskeletal Function Assessment Dysfunction Index (SMFA DI) and the Short Form-36 Physical Component Summary (SF-36 PCS) scores among patients undergoing operative management of tibial fractures. STUDY DESIGN AND SETTING: Between July 2000 and September 2005, we enrolled 1,319 skeletally mature patients with open or closed fractures of the tibial shaft that were managed with intramedullary nailing. Patients were asked to complete the SMFA Questionnaire and SF-36 at discharge and 3, 6, and 12 months post-surgical fixation. RESULTS: The SMFA DI and SF-36 PCS scores were highly correlated at 3, 6, and 12 months post-surgical fixation. The difference in the mean standardized change scores for SMFA DI and SF-36 PCS, from 3 to 12 months post-surgical fixation, was not statistically significant. Both the SMFA DI and SF-36 PCS scores were able to discriminate between healed and nonhealed tibial fractures at 3, 6, and 12 months postsurgery. CONCLUSION: In patients with tibial-shaft fractures, the SMFA DI offered no significant advantages over the SF-36 PCS score. These results, along with the usefulness of SF-36 for comparing populations, recommend the SF-36 for assessing physical function in studies of patients with tibial fractures.

A method for the estimation of normative bone surface area to aid in objective CT-based fracture severity assessment.

The reliable assessment of fracture severity plays a critical part in treatment, providing essential information to guide clinical decision-making. However, current classification schemes such as the AO/OTA are constrained by limitations intrinsic to subjective categorical systems. A recently developed objective CT-based assessment methodology quantifies fracture severity by calculating the mechanical energy expended during bony fragmentation. Specifically, fracture energy is determined by comparing the bone free surface area in the fractured limb to that in the intact contralateral limb. Unfortunately, the contralateral limb is not routinely scanned in the course of fracture assessment. Consequently, fracture energy can not be obtained, since there is no datum against which to compare the fractured limb. To facilitate the application of this novel technique to large multi-center and retrospective studies where the intact contralateral CT scan is unavailable, this study aimed to establish a normative, anthropometrically scaled intact bone model to be used as a substitute datum. A mathematical model that estimated free bone surface area along the intact contralateral limb was regressed from a study group of 22 tibial plafond fracture patients. The regressed tibia model provided suitably accurate estimates of the directly measured intact surfaces areas (average error of 15%). The differences between regressed and actual bone surface areas did not ultimately affect the stratification of fracture severity, as fracture energy measures using the regressed model maintained a 0.90 concordance with the original analysis. The results from this study suggest that normative bone surface area can be incorporated into the novel CT-based objective fracture severity assessment technique.

The health economics of the treatment of long-bone non-unions.

A review of the existing evidence on economic costs of treatment of long-bone fracture non-unions has retrieved 9 papers. Mostly the tibial shaft non-unions have been utilised as models for these economic analyses. Novel treatment strategies like BMP-7 grafting, Ilizarov ring external fixation or supplementary use of therapeutic ultrasound devices have been compared with standard methods of treatment focusing on direct and indirect costs and expenses. A cost-identification query was conducted and revealed costs of pound 15,566, pound 17,200 and pound 16,330 for humeral, femoral, and tibial non-unions respectively on a "best-case scenario". The existing scientific evidence can only imply the extent of the economic burden of long-bone non-unions. Further systematic studies are needed to assess the direct medical, direct non-medical, indirect, and monetised quality of life and psychosocial costs of non-unions.