An international validation of the AO spine subaxial injury classification system

Purpose

To validate the AO Spine Subaxial Injury Classification System with participants of various experience levels, subspecialties, and geographic regions.

Methods

A live webinar was organized in 2020 for validation of the AO Spine Subaxial Injury Classification System. The validation consisted of 41 unique subaxial cervical spine injuries with associated computed tomography scans and key images. Intraobserver reproducibility and interobserver reliability of the AO Spine Subaxial Injury Classification System were calculated for injury morphology, injury subtype, and facet injury. The reliability and reproducibility of the classification system were categorized as slight (ƙ = 0–0.20), fair (ƙ = 0.21–0.40), moderate (ƙ = 0.41–0.60), substantial (ƙ = 0.61–0.80), or excellent (ƙ = > 0.80) as determined by the Landis and Koch classification.

Results

A total of 203 AO Spine members participated in the AO Spine Subaxial Injury Classification System validation. The percent of participants accurately classifying each injury was over 90% for fracture morphology and fracture subtype on both assessments. The interobserver reliability for fracture morphology was excellent (ƙ = 0.87), while fracture subtype (ƙ = 0.80) and facet injury were substantial (ƙ = 0.74). The intraobserver reproducibility for fracture morphology and subtype were excellent (ƙ = 0.85, 0.88, respectively), while reproducibility for facet injuries was substantial (ƙ = 0.76).

Conclusion

The AO Spine Subaxial Injury Classification System demonstrated excellent interobserver reliability and intraobserver reproducibility for fracture morphology, substantial reliability and reproducibility for facet injuries, and excellent reproducibility with substantial reliability for injury subtype.

     

The AO spine upper cervical injury classification system: Do work setting or trauma center affiliation affect classification accuracy or reliability?

PurposeTo assess the accuracy and reliability of the AO Spine Upper Cervical Injury Classification System based on a surgeons’ work setting and trauma center affiliation.MethodsA total of 275 AO Spine members participated in a validation of 25 upper cervical spine injuries, which were evaluated by computed tomography (CT) scans. Each participant was grouped based on their work setting (academic, hospital-employed, or private practice) and their trauma center affiliation (Level I, Level II or III, and Level IV or no trauma center). The classification accuracy was calculated as percent of correct classifications, while interobserver reliability, and intraobserver reproducibility were evaluated based on Fleiss’ Kappa coefficient.ResultsThe overall classification accuracy for surgeons affiliated with a level I trauma center was significantly greater than participants affiliated with a level II/III center or a level IV/no trauma center on assessment one (p₁<0.0001) and two (p₂ = 0.0003). On both assessments, surgeons affiliated with a level I or a level II/III trauma center were significantly more accurate at identifying IIIB injury types (p₁ = 0.0007; p₂ = 0.0064). Academic surgeons and hospital employed surgeons were significantly more likely to correctly classify type IIIB injuries on assessment one (p₁ = 0.0146) and two (p₂ = 0.0015). When evaluating classification reliability, the largest differences between work settings and trauma center affiliations was identified in type IIIB injuries.ConclusionType B injuries are the most difficult injury type to correctly classify. They are classified with greater reliability and classification accuracy when evaluated by academic surgeons, hospital-employed surgeons, and surgeons associated with higher-level trauma centers (I or II/III).     

The reliability of the AOSpine Thoracolumbar Spine Injury Classification System in children: an international validation study

PurposeTo evaluate the AOSpine Thoracolumbar Spine Injury Classification System and if it is reliable and reproducible when applied to the paediatric population globally.MethodsA total of 12 paediatric orthopaedic surgeons were asked to review MRI and CT imaging of 25 paediatric patients with thoracolumbar spine traumatic injuries, in order to determine the classification of the lesions observed. The evaluators classified injuries into primary categories: A, B and C. Interobserver reliability was assessed for the initial reading by Fleiss’s kappa coefficient (k_F) along with 95% confidence intervals (CI). For A and B type injuries, sub-classification was conducted including A0-A4 and B1-B2 subtypes. Interobserver reliability across subclasses was assessed using Krippendorff’s alpha (α_k) along with bootstrapped 95% CIs. A second round of classification was performed one-month later. Intraobserver reproducibility was assessed for the primary classifications using Fleiss’s kappa and sub-classification reproducibility was assessed by Krippendorff’s alpha (α_k) along with 95% CIs.ResultsIn total, 25 cases were read for a total of 300 initial and 300 repeated evaluations. Adjusted interobserver reliability was almost perfect (kF = 0.74; 95% CI 0.71 to 0.78) across all observers. Sub-classification reliability was substantial (α_k= 0.67; 95% CI 0.51 to 0.81), Adjusted intraobserver reproducibility was almost perfect (kF = 0.91; 95% CI 0.83 to 0.99) for both primary classifications and for sub-classifications (α_k = 0.88; 95% CI 0.83 to 0.93).ConclusionThe inter- and intraobserver reliability for the AOSpine Thoracolumbar Spine Injury Classification System was high amongst paediatric orthopaedic surgeons. The AOSpine Thoracolumbar Spine Injury Classification System is a promising option as a uniform fracture classification in children.Level of EvidenceIII     

Reliability and reproducibility analysis of the AOSpine thoracolumbar spine injury classification system by Chinese spinal surgeons

Purpose

The objective of this study was to analyze the interobserver reliability and intraobserver reproducibility of the new AOSpine thoracolumbar spine injury classification system in young Chinese orthopedic surgeons with different levels of experience in spinal trauma. Previous reports suggest that the new AOSpine thoracolumbar spine injury classification system demonstrates acceptable interobserver reliability and intraobserver reproducibility. However, there are few studies in Asia, especially in China.

Methods

The AOSpine thoracolumbar spine injury classification system was applied to 109 patients with acute, traumatic thoracolumbar spinal injuries by two groups of spinal surgeons with different levels of clinical experience. The Kappa coefficient was used to determine interobserver reliability and intraobserver reproducibility.

Results

The overall Kappa coefficient for all cases was 0.362, which represents fair reliability. The Kappa statistic was 0.385 for A-type injuries and 0.292 for B-type injuries, which represents fair reliability, and 0.552 for C-type injuries, which represents moderate reliability. The Kappa coefficient for intraobserver reproducibility was 0.442 for A-type injuries, 0.485 for B-type injuries, and 0.412 for C-type injuries. These values represent moderate reproducibility for all injury types. The raters in Group A provided significantly better interobserver reliability than Group B (P < 0.05). There were no between-group differences in intraobserver reproducibility.

Conclusions

This study suggests that the new AO spine injury classification system may be applied in day-to-day clinical practice in China following extensive training of healthcare providers. Further prospective studies in different healthcare providers and clinical settings are essential for validation of this classification system and to assess its utility.

     

Interobserver and intraobserver variations in tibial pilon fracture classification systems

BackgroundTibial pilon injuries are a complex group of fractures, whose classification and radiological assessment has been under constant reform. Till date, there is no universally accepted classification system.ObjectiveTo determine the interobserver agreement and intraobserver reproducibility of Ruedi and Allgower, AO, and Topliss et al. classification systems for tibial pilon fractures, with CT scans.MethodForty-seven CT scans of tibial pilon fractures were evaluated independently by 5 orthopaedic surgeons. Fractures were classified according to Ruedi and Allgower, AO and Topliss et al. types. Assessment was done on two occasions, eight weeks apart.ResultsThe interobserver reliability and intraobserver reproducibility for Ruedi and Allgower, AO and Topliss et al. classifications showed only moderate agreement. The interobserver agreement was dependent on the familiarity and specificity of the classification system.ConclusionCurrently used classification systems for tibial pilon fracture have moderate interobserver and intraobserver agreements, even with the help of CT scans. Therefore Tibial pilon fracture classification still remains largely undetermined.     

Reliability analysis of the AOSpine thoracolumbar spine injury classification system by a worldwide group of naïve spinal surgeons

Purpose

The aims of this study were (1) to demonstrate the AOSpine thoracolumbar spine injury classification system can be reliably applied by an international group of surgeons and (2) to delineate those injury types which are difficult for spine surgeons to classify reliably.

Methods

A previously described classification system of thoracolumbar injuries which consists of a morphologic classification of the fracture, a grading system for the neurologic status and relevant patient-specific modifiers was applied to 25 cases by 100 spinal surgeons from across the world twice independently, in grading sessions 1 month apart. The results were analyzed for classification reliability using the Kappa coefficient (κ).

Results

The overall Kappa coefficient for all cases was 0.56, which represents moderate reliability. Kappa values describing interobserver agreement were 0.80 for type A injuries, 0.68 for type B injuries and 0.72 for type C injuries, all representing substantial reliability. The lowest level of agreement for specific subtypes was for fracture subtype A4 (Kappa = 0.19). Intraobserver analysis demonstrated overall average Kappa statistic for subtype grading of 0.68 also representing substantial reproducibility.

Conclusion

In a worldwide sample of spinal surgeons without previous exposure to the recently described AOSpine Thoracolumbar Spine Injury Classification System, we demonstrated moderate interobserver and substantial intraobserver reliability. These results suggest that most spine surgeons can reliably apply this system to spine trauma patients as or more reliably than previously described systems.

     

AO spine injury classification system: a revision proposal for the thoracic and lumbar spine

Purpose

The AO Spine Classification Group was established to propose a revised AO spine injury classification system. This paper provides details on the rationale, methodology, and results of the initial stage of the revision process for injuries of the thoracic and lumbar (TL) spine.

Methods

In a structured, iterative process involving five experienced spine trauma surgeons from various parts of the world, consecutive cases with TL injuries were classified independently by members of the classification group, and analyzed for classification reliability using the Kappa coefficient (κ) and for accuracy using latent class analysis. The reasons for disagreements were examined systematically during review meetings. In four successive sessions, the system was revised until consensus and sufficient reproducibility were achieved.

Results

The TL spine injury system is based on three main injury categories adapted from the original Magerl AO concept: A (compression), B (tension band), and C (displacement) type injuries. Type-A injuries include four subtypes (wedge-impaction/split-pincer/incomplete burst/complete burst); B-type injuries are divided between purely osseous and osseo-ligamentous disruptions; and C-type injuries are further categorized into three subtypes (hyperextension/translation/separation). There is no subgroup division. The reliability of injury types (A, B, C) was good (κ = 0.77). The surgeons’ pairwise Kappa ranged from 0.69 to 0.90. Kappa coefficients κ for reliability of injury subtypes ranged from 0.26 to 0.78.

Conclusions

The proposed TL spine injury system is based on clinically relevant parameters. Final evaluation data showed reasonable reliability and accuracy. Further validation of the proposed revised AO Classification requires follow-up evaluation sessions and documentation by more surgeons from different countries and backgrounds and is subject to modification based on clinical parameters during subsequent phases.     

Cervical spine injury severity score. Assessment of reliability

BACKGROUND: Systems for classifying cervical spine injury most commonly use mechanistic or morphologic terms and do not quantify the degree of stability. Along with neurologic function, stability is a major determinant of treatment and prognosis. The goal of our study was to investigate the reliability of a method of quantifying the stability of subaxial (C3-C7) cervical spine injuries. METHODS: A quantitative system was developed in which an analog score of 0 to 5 points is assigned, on the basis of fracture displacement and severity of ligamentous injury, to each of four spinal columns (anterior, posterior, right pillar, and left pillar). The total possible score thus ranges from 0 to 20 points. Fifteen examiners assigned scores after reviewing the plain radiographs and computed tomography images of thirty-four consecutive patients with cervical spine injuries. The scores were then evaluated for interobserver and intraobserver reliability with use of intraclass correlation coefficients. RESULTS: The mean intraobserver and interobserver intraclass correlation coefficients for the fifteen reviewers were 0.977 and 0.883, respectively. Association between the scores and clinical data was also excellent, as all patients who had a score of > or =7 points had surgery. Similarly, eleven of the fourteen patients with a score of > or =7 points had a neurologic deficit compared with only three of the twenty with a score of <7 points. CONCLUSIONS: The Cervical Spine Injury Severity Score had excellent intraobserver and interobserver reliability. We believe that quantifying stability on the basis of fracture morphology will allow surgeons to better characterize these injuries and ultimately lead to the development of treatment algorithms that can be tested in clinical trials.     

Reliability and reproducibility analysis of the AOSpine Sacral Fractures Classification System by spinal and pelvic surgeons

Study DesignRetrospective Cohort StudyObjectivesThe AOSpine Sacral Classification System was proposed as a comprehensive and universally accepted new classification for Sacral Fractures, and was recently internally validated. However, an external, independent and multidisciplinary reports on validation of this classification is lacking. Aim of the present study is to analyze the interobserver reliability and intraobserver reproducibility of the AOSpine Sacral Classification System for Sacral Fractures between orthopedic spinal and pelvic surgeons with different levels of experience.MethodsOur institutional database was searched to retrieve patients with acute, traumatic sacral injury admitted from June 2017 to June 2020. For each patients, X-Rays and CT scans were collected. Three Orthopedic Pelvic Surgeons (Group A) and three Spine Surgeons (Group B), with different level of experience (Junior, 〈 5 years; Middle, 5–10 years; Expert 〉 10 years) independently classified all the sacral fractures included in the dataset, with two separate evaluation three weeks apart. Both intra and interobserver reliability were calculated with k-coefficient.ResultsOverall, 150 patients were included in the final dataset, for a total of 1800 different assessments, with all the subtypes reported. The intraobserver reproducibility for the whole group was substantial (κ=0.72). Overall, the interobserver reliability was moderate, with a κ=0.57. When only fracture type was taken in account, the κ value became substantial (κ=0.62). No significant differences were found comparing group A and group B (0.55 vs κ 0.55, p>0.05). No significant differences according to surgeon's experience were found; however, the κ value was slightly lower among the junior surgeons.ConclusionsOur findings confirmed the reliability and reproducibility of this classification in clinical practice. In the current study the surgeon's expertise (pelvic and spinal trauma) and the level of experience does not influence the reliability of the classification system.     

Comparison between reliability of Schatzker's classification and CT based four quadrant classification for tibial plateau fractures

IntroductionConventionally used Schatzker and AO/OTA classification, do not identify posterior column injuries in tibial plateau fractures. CT based Four quadrant classification, has been proposed to identify fractures of tibial plateau and help in surgical planning of treatment. However, to assess its validity, there is scanty literature about its reliability (inter and intra-observer variation) and comparison of its reliability with that of the more popular Schatzker classification in classifying tibial plateau fracture.Material and methodsX-rays and CT scans of 35 patients (18–65 years) of closed tibial plateau fractures were assessed by 5 Orthopaedic surgeons and classified by both Schatzker's and Four Quadrant Classification. A similar observation was recorded after 2 months. All observers were blinded for the demographic and clinical details of the patients. Their responses were noted and interobserver and Intraobserver variation was calculated. Kappa Test of Cohen was used to determine the level of agreement, as per Landis and Koch's criteria. The reliability of four quadrant classification was also compared with that of Schatzker's classification.ResultsThere was a moderate agreement in interobserver variation in observations for Schatzker's classification (on X-rays) which improved to substantial agreement when the observations were recorded after showing both CT and X-rays. The intraobserver variation had substantial agreement. On the other hand, there was a perfect agreement in both intra- and interobserver variation for Four Quadrant Classification. This difference between the reliability of both classifications was statistically significant (p < 0.001).ConclusionsFour Quadrant classification is a more reliable classification having a better agreement on interobserver and intraobserver variation.     

Assessment of two thoracolumbar fracture classification systems as used by multiple surgeons

BACKGROUND: The reproducibility and repeatability of modern systems for classification of thoracolumbar injuries have not been sufficiently studied. We assessed the interobserver and intraobserver reproducibility of the AO (Arbeitsgemeinschaft für Osteosynthesefragen) classification and compared it with that of the Denis classification. Our purpose was to determine whether the newer, AO system had better reproducibility than the older, Denis classification. METHODS: Anteroposterior and lateral radiographs and computerized tomography scans (axial images and sagittal reconstructions) of thirty-one acute traumatic fractures of the thoracolumbar spine were presented to nineteen observers, all trained spine surgeons, who classified the fractures according to both the AO and the Denis classification systems. Three months later, the images of the thirty-one fractures were scrambled into a different order, and the observers repeated the classification. The Cohen kappa (kappa) test was used to determine interobserver and intraobserver agreement, which was measured with regard to the three basic classifications in the AO system (types A, B, and C) as well as the nine subtypes of that system. We also measured the agreement with regard to the four basic types in the Denis classification (compression, burst, seat-belt, and fracture-dislocation) and with regard to the sixteen subtypes of that system. RESULTS: The AO classification was fairly reproducible, with an average kappa of 0.475 (range, 0.389 to 0.598) for the agreement regarding the assignment of the three types and an average kappa of 0.537 for the agreement regarding the nine subtypes. The average kappa for the agreement regarding the assignment of the four Denis fracture types was 0.606 (range, 0.395 to 0.702), and it was 0.173 for agreement regarding the sixteen subtypes. The intraobserver agreement (repeatability) was 82% and 79% for the AO and Denis types, respectively, and 67% and 56%, for the AO and Denis subtypes, respectively. CONCLUSIONS: Both the Denis and the AO system for the classification of spine fractures had only moderate reliability and repeatability. The tendency for well-trained spine surgeons to classify the same fracture differently on repeat testing is a matter of some concern.     

Gunshot femoral shaft fractures: is the current classification system reliable?

The reliability of the AO/Orthopaedic Trauma Association classification system has not been evaluated for diaphyseal fractures or fractures attributable to gunshot injuries. Therefore, the current authors assessed its reliability for diaphyseal femur fractures and investigated the effect of a gunshot mechanism of injury. Forty-seven diaphyseal femur fractures, 23 caused by gunshots and 24 caused by blunt trauma, were classified by four observers on two occasions. The interobserver and intraobserver reliability of each level of the AO/Orthopaedic Trauma Association classification was assessed with kappa statistics. Determination of fracture type had substantial interobserver and intraobserver reliability for gunshot and blunt injuries. Reliability decreased at the subsequent levels of the classification. Fractures caused by gunshots compared with those caused by blunt trauma were characterized by significantly lower interobserver agreement on fracture group (k = 0.26 versus 0.45) and subgroup (k = 0.21 versus 0.38). The AO/Orthopaedic Trauma Association classification system has substantial interobserver and intraobserver reliability when evaluating the type of diaphyseal femur fractures. Determination of fracture group and subgroup, however, progressively reduces the reliability of the classification, especially for fractures caused by a gunshot. Diaphyseal femur fractures caused by gunshots, by means of their fracture patterns, cannot be classified reliably with the AO/Orthopaedic Trauma Association classification system.     

An independent inter- and intra-observer agreement assessment of the AOSpine upper cervical injury classification system

BACKGROUND CONTEXTThe complex anatomy of the upper cervical spine resulted in numerous separate classification systems of upper cervical spine trauma. The AOSpine upper cervical classification system (UCCS) was recently described; however, an independent agreement assessment has not been performed.PURPOSETo perform an independent evaluation of the AOSpine UCCS.STUDY DESIGNAgreement study.PATIENT SAMPLEEighty-four patients with upper cervical spine injuries.OUTCOME MEASURESInter-observer agreement; intra-observer agreement.METHODSComplete imaging studies of 84 patients with upper cervical spine injuries, including all morphological types of injuries defined by the AOSpine UCCS were selected and classified by six evaluators (from three different countries). The 84 cases were presented to the same raters randomly after a 4-week interval for repeat evaluation. The Kappa coefficient (κ) was used to determine inter- and intra-observer agreement.RESULTSThe interobserver agreement was almost perfect when considering the fracture site (I, II or III), with κ=0.82 (0.78–0.83), but the agreement according to the site and type level was moderate, κ=0.57 (0.55–0.65). The intra-observer agreement was almost perfect considering the injury, with κ=0.83 (0.78–0.86), while according to site and type was substantial, κ=0.69 (0.67–0.71).CONCLUSIONSWe observed only a moderate inter-observer agreement using this classification. We believe our results can be explained because this classification attempted to organize many different injury types into a single scheme.     

The Subaxial Cervical Spine Injury Classification System: an external agreement validation study

Background contextIn 2007, the Subaxial Cervical Spine Injury Classification (SLIC) system was introduced demonstrating moderate reliability in an internal validation study.PurposeTo assess the agreement on the SLIC system using clinical data from a spinal trauma population and whether the SLIC treatment algorithm outcome improved agreement on treatment decisions among surgeons.Study designAn external classification validation study.Patient sampleTwelve spinal surgeons (five consultants and seven fellows) assessed 51 randomly selected cases.Outcome measuresRaw agreement, Fleiss kappa, and intraclass correlation coefficient statistics were used for reliability analysis. Majority rules and latent class modeling were used for accuracy analysis.MethodsFifty-one randomly selected cases with significant injuries of the cervical spine from a prospective consecutive series of trauma patients were assessed using the SLIC system. Neurologic details, plain radiographs, and computed tomography scans were available for all cases as well as magnetic resonance imaging in 21 cases (41%). No funds were received in support of this study. The authors have no conflict of interest in the subject of this article.ResultsThe inter-rater agreement on the most severely affected level of injury was strong (κ=0.76). The agreement on the morphologic injury characteristics was poor (κ=0.29) and agreement on the integrity of the discoligamentous complex was average (κ=0.46). The inter-rater agreement on the treatment verdict after the total SLIC injury severity score was slightly lower than the surgeons' agreement on personal treatment preference (κ=0.55 vs. κ=0.63). Latent class analysis was not converging and did not present accurate estimations of the true classification categories. Based on these findings, no second survey for testing intrarater agreement was performed.ConclusionsWe found poor agreement on the morphologic injury characteristics of the SLIC system, and its treatment algorithm showed no improved agreement on treatment decisions among surgeons. The authors discuss that the reproducibility of the SLIC system is likely to improve when unambiguous true morphologic injury characteristics are being implemented.     

A multilevel noncontiguous spinal fracture with cervical and thoracic spinal cord injury

Introduction and importanceA multi-level non-contiguous spinal fracture (MNSF) caused by a high-energy impact is a type of complex traumatic injury that is been frequently initially missed, and resulting in delayed diagnosis which adversely affects can result in spinal deformity and neurological deficit. This report describes the operative management of a patient with MNSF with spinal cord injury involving the cervical and thoracic vertebrae by cervical orthosis and posterior thoracic decompression and fusion.Case presentationAn 18-year-old male presented with extensive neck pain and paraplegia (ASIA A), following a motor vehicle accident. Radiographic imaging revealed MNSF: a non-displaced spinous process fracture of C5 (AO Spine subaxial cervical injury classification A0) with spinal cord injury combined with fracture-dislocation of T5 to T9 (AO Spine thoracolumbar injury classification C3). Posterior thoracic decompression and fusion was performed at T3 to T8. After the patient underwent the thoracic spine and cervical orthosis treatment, He received rehabilitation program and training transfer with wheelchair without caregiver. His sitting and balance were significantly improved at the 6 months follow-up. Although the lower extremity functions (ASIA A) may not improve due to the severe spinal cord injury.Clinical discussionMNSF with spinal cord injury following a high-velocity accident is an unstable and complex injury. Important of the clinical assessment and according to the injuries the treatment may vary.ConclusionsCervical orthosis was alternative treatment to preserve cervical motion treatment and posterior thoracic decompression with fixation is an effective option for patients in this MNSF with spinal cord injury.     

Interobserver and Intraobserver Reliability Assessment of Calcaneal Fracture Classification Systems

The aim of the present study was to assess the reliability of commonly used intra-articular calcaneal fracture classification systems and to compare them with the newer AO Integral Classification of Injuries (ICI) system. Forty computed tomography and radiographic images of 40 intra-articular calcaneal fractures were reviewed independently by 3 reviewers on 2 separate occasions and classified according to the Essex-Lopresti, Atkins, Zwipp and Tscherne, Sanders, and AO-ICI classification systems. The reviewers were unaware of the patients' identity and all aspects of clinical care. The data were analyzed using kappa (κ) statistics to assess the intra- and interobserver reliability. The κ values were calculated for Essex-Lopresti (κ = 0.85 intraobserver, κ = 0.78 interobserver), Atkins (κ = 0.42 intraobserver, κ = 0.73 interobserver), Zwipp and Tscherne (κ = 0.40 intraobserver, κ = 0.47 interobserver), Sanders (κ = 0.31 intraobserver, κ = 0.35 interobserver), and AO-ICI (κ = 0.41 intraobserver, κ = 0.33 interobserver). The AO-ICI classification system had levels of reproducibility similar to that of the Sanders classification, currently the most widely used system. The Essex-Lopresti classification demonstrated improved reliability compared with that reported in previous studies. This can be attributed to using sagittal computed tomography images, in addition to the originally described plain radiographs, for assessment. This improvement is relevant because of its accepted prognostic predictability.     

Two and three-dimensional computed tomography for the classification and management of distal humeral fractures. Evaluation of reliability and diagnostic accuracy

BACKGROUND: Complex fractures of the distal part of the humerus can be difficult to characterize on plain radiographs and two-dimensional computed tomography scans. We tested the hypothesis that three-dimensional reconstructions of computed tomography scans improve the reliability and accuracy of fracture characterization, classification, and treatment decisions. METHODS: Five independent observers evaluated thirty consecutive intra-articular fractures of the distal part of the humerus for the presence of five fracture characteristics: a fracture line in the coronal plane; articular comminution; metaphyseal comminution; the presence of separate, entirely articular fragments; and impaction of the articular surface. Fractures were also classified according to the AO/ASIF Comprehensive Classification of Fractures and the classification system of Mehne and Matta. Two rounds of evaluation were performed and then compared. Initially, a combination of plain radiographs and two-dimensional computed tomography scans (2D) were evaluated, and then, two weeks later, a combination of radiographs, two-dimensional computed tomography scans, and three-dimensional reconstructions of computed tomography scans (3D) were assessed. RESULTS: Three-dimensional computed tomography improved both the intraobserver and the interobserver reliability of the AO classification system and the Mehne and Matta classification system. Three-dimensional computed tomography reconstructions also improved the intraobserver agreement for all fracture characteristics, from moderate (average kappa [kappa2D] = 0.554) to substantial agreement (kappa3D = 0.793). The addition of three-dimensional images had limited influence on the interobserver reliability and diagnostic characteristics (sensitivity, specificity, and accuracy) for the recognition of specific fracture characteristics. Three-dimensional computed tomography images improved intraobserver agreement (kappa2D = 0.62 compared with kappa3D = 0.75) but not interobserver agreement (kappa2D = 0.24 compared with kappa3D = 0.28) for treatment decisions. CONCLUSIONS: Three-dimensional reconstructions improve the reliability, but not the accuracy, of fracture classification and characterization. The influence of three-dimensional computed tomography was much more notable for intraobserver comparisons than for interobserver comparisons, suggesting that different observers see different things in the scans-most likely a reflection of the training, knowledge, and experience of the observer with regard to these relatively uncommon and complex injuries.     

Interobserver and intraobserver reliability of the classification and diagnosis for ossification of the posterior longitudinal ligament of the cervical spine

Purpose

Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine has been classified into four types by lateral plain radiographs, but the reliability of the classification and of the diagnosis of either cervical OPLL or cervical spondylotic myelopathy (CSM) was unknown. We investigated the interobserver and intraobserver reliability of the classification and diagnosis for OPLL by radiographs and computed tomography (CT) images.

Methods

A total of 16 observers classified each patient’s images into five groups; OPLL continuous, segmental, mixed, circumscribed type, or CSM. To evaluate interobserver reliability, the observers first classified only radiograph images, and next both radiographs and CT images. On another day they followed the same procedure to evaluate intraobserver reliability. We also evaluated interobserver and intraobserver reliability of the diagnosis of either cervical OPLL or CSM.

Results

Interobserver reliability of the classification with radiographs only showed moderate agreement, but interobserver reliability with both radiographs and CT images showed substantial agreement. Intraobserver of reliability the classification was also improved by additional CT images. Interobserver reliability of the diagnosis with both radiographs and CT images was almost similar to with radiographs only. Intraobserver reliability of the diagnosis was improved by additional CT images.

Conclusions

This study suggested that the reliability of the classification and diagnosis for cervical OPLL was improved by additional CT images. We propose that diagnostic criteria for OPLL include both radiographs and CT images.     

Reliability assessment of AOSpine thoracolumbar spine injury classification system and Thoracolumbar Injury Classification and Severity Score (TLICS) for thoracolumbar spine injuries: results of a multicentre study

Purpose

The aim of this multicentre study was to determine whether the recently introduced AOSpine Classification and Injury Severity System has better interrater and intrarater reliability than the already existing Thoracolumbar Injury Classification and Severity Score (TLICS) for thoracolumbar spine injuries.

Methods

Clinical and radiological data of 50 consecutive patients admitted at a single centre with a diagnosis of an acute traumatic thoracolumbar spine injury were distributed to eleven attending spine surgeons from six different institutions in the form of PowerPoint presentation, who classified them according to both classifications. After time span of 6 weeks, cases were randomly rearranged and sent again to same surgeons for re-classification. Interobserver and intraobserver reliability for each component of TLICS and new AOSpine classification were evaluated using Fleiss Kappa coefficient (k value) and Spearman rank order correlation.

Results

Moderate interrater and intrarater reliability was seen for grading fracture type and integrity of posterior ligamentous complex (Fracture type: k = 0.43 ± 0.01 and 0.59 ± 0.16, respectively, PLC: k = 0.47 ± 0.01 and 0.55 ± 0.15, respectively), and fair to moderate reliability (k = 0.29 ± 0.01 interobserver and 0.44+/0.10 intraobserver, respectively) for total score according to TLICS. Moderate interrater (k = 0.59 ± 0.01) and substantial intrarater reliability (k = 0.68 ± 0.13) was seen for grading fracture type regardless of subtype according to AOSpine classification. Near perfect interrater and intrarater agreement was seen concerning neurological status for both the classification systems.

Conclusions

Recently proposed AOSpine classification has better reliability for identifying fracture morphology than the existing TLICS. Additional studies are clearly necessary concerning the application of these classification systems across multiple physicians at different level of training and trauma centers to evaluate not only their reliability and reproducibility, but also the other attributes, especially the clinical significance of a good classification system.