How reliable are reliability studies of fracture classifications? A systematic review of their methodologies

How reliable is the distinction between thoracolumbar AO type A3 and A4 fractures? A systematic literature review

PURPOSE

The AOSpine classification divides thoracolumbar burst fractures into A3 and A4 fractures; nevertheless, past research has found inconsistent interobserver reliability in detecting those two fracture patterns. This systematic analysis aims to synthesize data on the reliability of discriminating between A3 and A4 fractures.

METHODS

We searched PubMed, Scopus, and the Web of Science for studies reporting the inter- and intra-observer reliability of detecting thoracolumbar AO A3 and A4 fractures using computed tomography (CT). The search spanned 2013 to 2023 and included both primarily reliability and observational comparative studies. We followed the PRISMA guidelines and used the modified COSMIN checklist to assess the studies' quality. Kappa coefficient (k) values were categorized according to Landis and Koch, from slight to excellent.

RESULTS

Of the 396 identified studies, nine met the eligibility criteria; all were primarily reliability studies except one observational study. Interobserver k values for A3/A4 fractures varied widely among studies (0.19-86). The interobserver reliability was poor in two studies, fair in one study, moderate in four studies, and excellent in two studies. Only two studies reported intra-observer reliability, showing fair and excellent agreement. The included studies revealed significant heterogeneity in study design, sample size, and interpretation methods.

CONCLUSION

Considerable variability exists in interobserver reliability for distinguishing A3 and A4 fractures from slight to excellent agreement. This variability might be attributed to methodological heterogeneity among studies, limitations of reliability analysis, or diagnostic pitfalls in differentiating between A3 and A4. Most observational studies comparing the outcome of A3 and A4 fractures do not report interobserver agreement, and this should be considered when interpreting their results.

The ballistic articular structure injury classification (BASIC) system: clarifying ballistic articular injuries

PURPOSE

This study aims to (1) devise a classification system to categorize and manage ballistic fractures of the knee, hip, and shoulder; (2) assess the reliability of this classification compared to current classification schemas; and (3) determine the association of this classification with surgical management.

METHODS

We performed a retrospective review of a prospectively collected trauma database at an urban level 1 trauma centre. The study included 147 patients with 169 articular fractures caused by ballistic trauma to the knee, hip, and shoulder. Injuries were selected based on radiographic criteria from plain radiographs and CT scans. The AO/OTA classification system's reliability was compared to that of the novel ballistic articular injury classification system (BASIC), developed using a nominal group approach. The BASIC system's ability to guide surgical decision-making, aiming to achieve stable fixation and minimize post-traumatic arthritis, was also evaluated.

RESULTS

The BASIC system was created after analysing 73 knee, 62 hip, and 34 shoulder fractures. CT scans were used in 88% of cases, with 44% of patients receiving surgery. The BASIC classification comprises five subgroups, with a plus sign indicating the need for soft tissue intervention. Interrater reliability showed fair agreement for AO/OTA (k = 0.373) and moderate agreement for BASIC (k = 0.444). The BASIC system correlated strongly with surgical decisions, with an 83% concurrence in treatment choices based on chart reviews.

CONCLUSIONS

Conventional classification systems provide limited guidance for ballistic articular injuries. The BASIC system offers a pragmatic and reproducible alternative, with potential to inform treatment decisions for knee, hip, and shoulder ballistic injuries. Further research is needed to validate this system and its correlation with patient outcomes.

LEVEL OF EVIDENCE

Level III, Diagnostic Study.

The 100 most cited articles in artificial intelligence related to orthopedics

Background

This bibliometric study aimed to identify and analyze the top 100 articles related to artificial intelligence in the field of orthopedics.

Methods

The articles were assessed based on their number of citations, publication years, countries, journals, authors, affiliations, and funding agencies. Additionally, they were analyzed in terms of their themes and objectives. Keyword co-occurrence, co-citation of authors, and co-citation of references analyses were conducted using VOSviewer (version 1.6.19).

Results

The number of citations of these articles ranged from 32 to 272, with six papers having more than 200 citations The years of 2019 (n: 37) and 2020 (n: 19) together constituted 56% of the list. The USA was the leading contributor country to this field (n: 61). The most frequently used keywords were "machine learning" (n: 26), "classification" (n: 18), "deep learning" (n: 16), "artificial intelligence" (n: 14), respectively. The most common themes were decision support (n: 25), fracture detection (n: 24), and osteoarthrtitis staging (n: 21). The majority of the studies were diagnostic in nature (n: 85), with only two articles focused on treatment.

Conclusions

This study provides valuable insights and presents the historical perspective of scientific development on artificial intelligence in the field of orthopedics. The literature in this field is expanding rapidly. Currently, research is generally done for diagnostic purposes and predominantly focused on decision support systems, fracture detection, and osteoarthritis classification.

Reliability of the CURL classification for proximal ulna fracture-dislocations of the elbow

Background

Proximal ulna fracture-dislocations are challenging injuries with a myriad of existing classification systems. The Coronoid, proximal Ulna, Radius, and Ligaments classification (CURL) is a simple framework designed to focus attention on the key components affecting outcome and guide surgical management. This study evaluates interobserver and intraobserver reliability of this new classification.

Methods

Four observers independently reviewed plain radiographs and computed tomography (CT) scans of patients with proximal ulna fracture-dislocations. Each observer scored the Coronoid (C), proximal Ulna (U), and Radius (R) components for each fracture on 2 occasions. The osseous components were subclassified as 'intact', 'simple', or 'complex'. The Ligament component (L) was not rated as this requires intraoperative classification. Interobserver and intraobserver reliability was calculated using Cohen's weighted kappa coefficients. X-ray and CT were compared for patients with both imaging modalities. The Landis and Koch criteria were used to interpret the strength of the kappa statistics.

Results

One hundred seventy seven patients had plain X-rays; 58 patients had both X-ray and CT scans. Overall, in the X-ray only cohort, there was 'almost perfect' interobserver reliability for the radial head (k = 0.94) and coronoid (k = 0.83), and 'substantial' reliability (k = 0.68) for the proximal ulna. For the X-ray and CT cohort, interobserver reliability was 'almost perfect' across both modalities for the radial head (k = 0.88 and k = 0.93, respectively) and 'moderate' for the proximal ulna (k = 0.48 and k = 0.52, respectively). For the coronoid, interobserver reliability for X-ray interpretation was 'substantial' (k = 0.74) and for CT was 'almost perfect' (k = 0.89). Intraobserver reliability was 'almost perfect' for all components, other than CT assessment of the proximal ulna which demonstrated 'substantial' reliability (k = 0.74).

Conclusion

The Coronoid, proximal Ulna, Radius, and Ligaments classification demonstrates strong interobserver and intraobserver reliability, supporting use of the classification for proximal ulna fracture-dislocations. CT is recommended for improved characterization of any fracture with a coronoid component.

"How the Wrightington classification of traumatic elbow instability can simplify the algorithm for treatment"

There are numerous injury patterns of elbow-fracture dislocation that can lead to confusion about the best surgical management. The Wrightington classification aims to provide a simple categorization based on the injury to the coronoid process and the three column concept of the elbow osseous stability that describes a medial column consisting of the anteromedial coronoid facet and sublime tubercle, the middlecolumn is the anterolateral coronoid facet, and the lateral column is the radial head and lateral ligament complex with a fulcrum for varus/valgus stability between the two coronoid facets. Injuries are classified as type A (anteromedial facet/medial-column), B (bifacet/ medial and middle-columns), B+ (bifacet with radial head/all three columns), C (combined radial head and anterolateral facet/middle and lateral-columns), D (distal to coronoid where coronoid is in continuity with olecranon process), and D+ (distal to coronoid with radial head fracture). With each bony injury pattern, we can anticipate which soft tissue constraints are likely to be involved and the importance of their repair to restore stability, and thereby develop algorithms for management. The Wrightington classification has been shown to be reliable and valid. A consecutive series of 60 patients with elbow-fracture dislocation managed according to the surgical algorithms of the Wrightington classification have been reported to have excellent outcomes with a median Mayo Elbow Performance Score of 100 (interquartile 85-100) and flexion/extension arc of movement of 123° (interquartile 101°-130°). In conclusion, the Wrightington classification of elbow-fracture dislocation is a comprehensive, reliable, and valid classification with treatment algorithms that are associated with good functional outcomes.

Inter-Observer and Intra-Observer Reliability Assessment of the Established Classification Systems for Periprosthetic Shoulder Fractures

This study evaluated the reliability and comprehensiveness of the Unified classification system (UCPF), Wright & Cofield, Worland and Kirchhoff classifications and related treatment recommendations for periprosthetic shoulder fractures (PPSFx). Two shoulder arthroplasty specialists (experts) and two orthopaedic residents (non-experts) assessed 20 humeral-sided and five scapula-sided cases of PPSFx. We used the unweighted Cohen's Kappa (κ) for measuring the intra-observer reliability and Krippendorff's alpha (α) for measuring the inter-observer reliability. The inter-rater reliabilities for the Wright & Cofield and Worland classifications were substantial for all groups. The expert and non-expert groups for UCPF also showed substantial inter-rater agreement. The all-rater group for the UCPF and the expert and non-expert group for the Kirchhoff classification revealed moderate inter-rater reliability. For the Kirchhoff classification, only fair inter-rater reliability was found for the non-expert group. Almost perfect intra-rater reliability was measured for all groups of the Wright & Cofield classification and the all-rater and expert groups of the UCPF. All groups of the Kirchhoff and Worland classifications and the group of non-experts for the UCPF had substantial intra-rater reliabilities. Regarding treatment recommendations, substantial inter-rater and moderate intra-rater reliabilities were found. Simple classification systems for PPSFx (Wright & Cofield, Worland) show the highest inter- and intra-observer reliability but lack comprehensiveness as they fail to describe scapula-sided fractures. The complex Kirchhoff classification shows limited reliability. The UCPF seems to offer an acceptable combination of comprehensiveness and reliability.

Is the Robinson classification of clavicle fractures accurate enough within the setting of the Swedish Fracture Register?

INTRODUCTION

In the Swedish Fracture Register (SFR) clavicle fractures are classified according to the Robinson classification. This study aimed to evaluate the accuracy of the classification of clavicle fractures in the SFR. A secondary aim was to assess inter- and intraobserver agreement.

MATERIALS AND METHODS

Clavicle fractures (n = 132) were randomly selected from the SFR and radiographs were requested for each patient from their treating departments. Not all radiographs could be acquired, and after exclusion, 115 fractures were independently classified by three expert raters blinded to patient information. The 115 fractures were classified on two occasions, 3 months apart. The raters' consensus classification was used as a gold standard that was compared to the classification registered in the SFR. The accuracy, defined as the degree of agreement between the gold standard and SFR classifications, was reported, as was the inter- and intraobserver agreement for the expert raters.

RESULTS

Agreement between the classification in the SFR and the gold standard classification was fair (kappa = 0.35). Fractures with only partial displacement were often incorrectly classified as fully displaced in the SFR (n = 31 of 78 displaced fractures in the SFR). The inter- and intraobserver agreement among the expert raters was almost perfect (interobserver kappa = 0.81-0.87, intraobserver kappa = 0.84-0.94).

CONCLUSIONS

The accuracy of the classification of clavicle fractures in the SFR was only fair, whereas the inter- and intraobserver agreement among the expert raters was almost perfect. Accuracy in the SFR may be improved if the classification instructions in the SFR are updated by incorporating the original classification displacement criteria, both in text and in illustrated form.

Reliability of the Garden Alignment Index and Valgus Tilt Measurement for Nondisplaced Femoral Neck Fractures

Anteroposterior (AP) alignment assessment for nondisplaced femoral neck fractures is important for determining the treatment strategy and predicting postoperative outcomes. AP alignment is generally measured using the Garden alignment index (GAI). However, its reliability remains unknown. We compared the reliability of GAI and a new AP alignment measurement (valgus tilt measurement [VTM]) using preoperative AP radiographs of nondisplaced femoral neck fractures. The study was designed as an intra- and inter-rater reliability analysis. The raters were four trauma surgeons who assessed 50 images twice. The main outcome was the intraclass correlation coefficient (ICC). To calculate intra- and inter-rater reliability, we used a mixed-effects model considering rater, patient, and time. The overall ICC (95% CI) of GAI and VTM for intra-rater reliability was 0.92 (0.89−0.94) and 0.86 (0.82−0.89), respectively. The overall ICC of GAI and VTM for inter-rater reliability was 0.92 (0.89−0.95), and 0.85 (0.81−0.88), respectively. The intra- and inter-rater reliability of GAI was higher in patients aged <80 years than in patients aged ≥80 years. Our results showed that GAI is a more reliable measurement method than VTM, although both are reliable. Variations in patient age should be considered in GAI measurements.

A new understanding of radiographic landmarks of the greater trochanter that indicate correct femoral rotation for measurement of femoral offset

Objectives

To establish and validate a novel method for aligning femoral rotation to accurately measure femoral offset for preoperative templating and component sizing, and to identify the physical location of two radiographic lines utilized in the described method.

Materials and methods

Cadaveric proximal femurs were skeletonized and mounted to a biaxial load frame. Two radiographic lines along the greater trochanter were identified fluoroscopically. The femurs were rotated, and images were taken when the lines appeared superimposed, then in 2-degree increments to 10° of internal and external rotation, and at 30°. Radiographic femoral offset was calculated at each angle, and the maximum and aligned offsets were compared. Bone was removed until the radiographic lines disappeared, then a metal wire was inserted in place of the bone to confirm that the lines reappeared.

Results

The physical locations of the radiographic landmarks were on the anterior and posterior aspects of the greater trochanter. The mean true femoral offset was 38.2 mm (range, 30.5–46.3 mm). The mean aligned femoral offset was 37.3 mm (range, 29.3–46.3 mm), a 2.4% underestimation. The mean angle between aligned and true offset was 3.6° of external rotation (range, 10°ER-8°IR). Intra-rater intraclass correlation coefficient was 0.991.

Conclusion

Alignment of the radiographic lines created by the anterior and posterior aspects of the greater trochanter is a reliable and accurate rotational positioning method for measuring true femoral offset when using plain films or fluoroscopy, which can aid surgeons with preoperative templating and intraoperative component placement for total hip arthroplasty.

Reliability Evaluation of the New AO Spine-DGOU Classification for Osteoporotic Thoracolumbar Fractures

OBJECTIVES

To perform an interobserver and intraobserver agreement evaluation of the new AO Spine-DGOU classification system for osteoporotic thoracolumbar fractures (OFc).

METHODS

Complete imaging studies of 97 patients (radiographs, computed tomography scans, and magnetic resonance imaging) with osteoporotic thoracolumbar fractures were selected and classified using the OFc by 6 spine surgeons (3 senior surgeons with more than 15 years of experience and 3 surgeons with less than 15 years). After a 4-week interval, the same cases were presented to the same evaluators in a random sequence for a new classification assessment. The weighted kappa coefficient (wκ) was used to determine the interobserver and intraobserver agreement.

RESULTS

The interobserver agreement was moderate, wκ = 0.59 (95% confidence interval 0.54-0.64). The intraobserver agreement was fair, wκ = 0.35 (95% confidence interval 0.29-0.40). Interobserver agreement slightly improved for junior staff between first and second evaluation, suggesting a learning effect. Better agreement was obtained by senior staff at the interobserver and intraobserver agreement.

CONCLUSIONS

This independent assessment demonstrated that new OFc allows moderate interobserver agreement and fair intraobserver agreement. Further studies are necessary prior to its widespread adoption.

Poor reliability and reproducibility of 3 different radiographical classification systems for distal ulna fractures

BACKGROUND AND PURPOSE

Classification of fractures can be valuable for research purposes but also in clinical work. Especially with  are fractures, such as distal ulna fractures, a treatment algorithm based on a classification can be helpful. We compared 3 different  classification systems of distal ulna fractures and investigated their reliability and reproducibility.

PATIENTS AND METHODS

patients with 97 fractures of the distal ulna, excluding the ulnar styloid, were included. All fractures were  independently classified by 3 observers according to the classification by Biyani, AO/OTA 2007, and AO/OTA 2018. The classification process was repeated after a minimum of 3 weeks. We used Kappa value analysis to determine inter- and intra-rater agreement.

RESULTS

The inter-rater agreement of the AO/OTA 2007 classification was judged as fair, ĸ 0.40, whereas the agreement of AO/OTA 2018 and Biyani was moderate at ĸ 0.42 and 0.43 respectively. The intra-rater agreement was judged as moderate for all classifications.

INTERPRETATION

The differences between the classifications were small and the overall impression was that neither of them was good enough to be of substantial clinical value. The Biyani classification, being developed specifically for distal ulna fractures, was the easiest and most fitting for the fracture patterns seen in our material, but lacking options for fractures of the distal diaphysis. Standard radiographs were considered insufficient for an accurate classification. A better radiographic method combined with a revised classification might improve accuracy, reliability, and reproducibility.

Interobserver Reliability of Schatzker, AO Foundation-Orthopaedic Trauma Association, and Luo Classifications for Tibial Plateau Fractures: Does Three-Dimensional CT Improve Outcomes?

Objective

To assess the interobserver agreement of the most widely used classification systems (Schatzker, AO Foundation-Orthopaedic Trauma Association (AO-OTA), and Luo) and investigate the impact of multiplane CT scans on their reliability.

Methods

Twelve raters (seven consultants and five senior trainees) were invited to classify 25 cases of tibial plateau fracture randomly selected out of a large database. Initially, they were asked to classify the fracture according to Schatzker, AO-OTA, and Luo based on plain anteroposterior (AP) X-ray and axial CT images. This procedure was applied for 25 cases consecutively. Next, the raters are given access to the multiplanar CT views of the same cases and were requested to reclassify each case. The interobserver agreement was calculated using the Fleiss kappa coefficient.

Results

An overall fair inter-rater agreement was observed for the Schatzker classification based on the plain AP X-ray (k=0.361) with a slight improvement after three-dimensional (3D) plane CT views (X-ray: k=0.361; 3D CT: k=0.364). For the AO-OTA classification, the relevant values were 0.204 and 0.231 based on plain X-ray and multiplanar CT, respectively. Finally, the Luo classification achieved the highest scores among the three classification systems (k=0.498), but its inter-rater agreement can still be characterized as moderate. No statistically significant improvement in the interobserver agreement was found for any classification even if only the consultants’ subgroup was included in the data analysis.

Conclusion

All three classification systems failed to achieve a substantial agreement among the raters, with only a nonsignificant improvement after providing advanced imaging. This finding reflects the intrinsic weaknesses of the classification systems themselves rather than the disagreement on the fracture pattern due to unsatisfactory imaging.

Machine learning outperforms clinical experts in classification of hip fractures

Hip fractures are a major cause of morbidity and mortality in the elderly, and incur high health and social care costs. Given projected population ageing, the number of incident hip fractures is predicted to increase globally. As fracture classification strongly determines the chosen surgical treatment, differences in fracture classification influence patient outcomes and treatment costs. We aimed to create a machine learning method for identifying and classifying hip fractures, and to compare its performance to experienced human observers. We used 3659 hip radiographs, classified by at least two expert clinicians. The machine learning method was able to classify hip fractures with 19% greater accuracy than humans, achieving overall accuracy of 92%.

An inter- and intra-rater agreement assessment of a novel classification of pyogenic spinal infections

PURPOSE

Pola et al. described a clinical-radiological classification of pyogenic spinal infections (PSI) based on magnetic resonance imaging (MRI) features including vertebral destruction, soft tissue involvement, and epidural abscess, along with the neurological status. We performed an inter- and intra-observer agreement evaluation of this classification.

METHODS

Complete MRI studies of 80 patients with PSI were selected and classified using the scheme described by Pola et al. by seven evaluators. After a four-week interval, all cases were presented to the same assessors in a random sequence for repeat assessment. We used the weighted kappa statistics (wκ) to establish the inter- and intra-observer agreement.

RESULTS

The inter-observer agreement was substantial considering the main categories (wκ = 0.77; 0.71-0.82), but moderate considering the subtypes (wκ = 0.51; 0.45-0.58). The intra-observer agreement was substantial considering the main types (wκ = 0.65; 0.59-0.71), and moderate considering the subtypes (wκ = 0.58; 0.54-0.63).

CONCLUSION

The agreement at the main type level indicates that this classification allows adequate communication and may be used in clinical practice; at the subtypes level, the agreement is only moderate.

Avaliação das concordâncias intra e inter-observadores da nova classificação AO/OTA para fraturas da região trocantérica e do colo do fêmur

Objective  In the present study, we investigated the intra and interobserver agreement of the new Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification for fractures of the proximal extremity of the femur.

Methods  One hundred hip radiographs were selected from patients who suffered fractures of the trochanteric region or femoral neck. Four orthopedists, fellowship trained hip surgeons, and four orthopedic residents evaluated and classified fractures according to the new AO/OTA system on two separate occasions. The kappa (k) coefficient was used to evaluate intra and interobserver agreement in the different steps of the classification, namely: type , group , subgroup , and qualifier.

Results  Hip surgery experts obtained almost perfect intraobserver agreement of type , substantial for group and, only moderate, for subgroup and qualifiers. The residents had lower performance, with substantial agreement for type, moderate for group , and reasonable for subgroup and qualifier. In the specialists' interobserver evaluation, there was also a gradual decrease in the agreement between type (almost perfect) and group (moderate), which was even lower for subgroup and qualifiers. Residents had a substantial interobserver agreement for type , moderate for group , and reasonable in the other branches.

Conclusion  The new AO/OTA classification for fractures of the trochanteric region and femoral neck showed intra and interobserver agreements considered appropriate for type and group , with a drop in the subsequent branches, that is, for subgroup and qualifier. Still, in relation to the old AO/OTA classification, there was an improvement in the agreements for subgroup.

Analysis of the mandibular canal course using unsupervised machine learning algorithm

Objectives

Anatomical structure classification is necessary task in medical field, but the inevitable variability of interpretation among experts makes reliable classification difficult. This study aims to introduce cluster analysis, unsupervised machine learning method, for classification of three-dimensional (3D) mandibular canal (MC) courses, and to visualize standard MC courses derived from cluster analysis in the Korean population.

Materials and methods

A total of 429 cone-beam computed tomography images were used. Four sites in the mandible were selected for the measurement of the MC course and four parameters, two vertical and two horizontal parameters were measured per site. Cluster analysis was carried out as follows: parameter measurement, parameter normalization, cluster tendency evaluation, optimal number of clusters determination, and k-means cluster analysis. The 3D MC courses were classified into three types with statistically significant mean differences by cluster analysis.

Results

Cluster 1 showed a smooth line running towards the lingual side in the axial view and a steep slope in the sagittal view. Cluster 2 ran in an almost straight line closest to the lingual and inferior border of mandible. Cluster 3 showed the pathway with a bent buccally in the axial view and an increasing slope in the sagittal view in the posterior area. Cluster 2 showed the highest distribution (42.1%), and males were more widely distributed (57.1%) than the females (42.9%). Cluster 3 comprised similar ratio of male and female cases and accounted for 31.9% of the total distribution. Cluster 1 had the least distribution (26.0%) Distributions of the right and left sides did not show a statistically significant difference.

Conclusion

The MC courses were automatically classified as three types through cluster analysis. Cluster analysis enables the unbiased classification of the anatomical structures by reducing observer variability and can present representative standard information for each classified group.

Evaluation of the Inter and Intra-Observer Reliability of the AO Classification of Intertrochanteric Fractures and the Device Choice (DHS, PFNA, and DCS) of Fixations

Background

ArbeitsgemeinschaftfürOsteosynthesefragen (AO) classification is the most frequently used tool to classify intertrochanteric fractures. However, there is limited evidence regarding its reliability. Therefore, this study was designed to evaluate inter-observer and intra-observer reliability of the AO-2018 intertrochanteric fracture classification.

Method

A retrospective study was conducted in Imam Khomeini Hospital Complex, on radiography of patients who came with intertrochanteric fractures from March 21, 2018, to March 19, 2019. Four orthopedic trauma surgeons assessed 96 anteroposterior pelvic radiographs of intertrochanteric fractures and classified using an AO intertrochanteric fracture classification of 2018. The reading and review of radiography were performed in 2 separate occasions in a 1-month interval. The inter-observer and intra-observer reliability was assessed using kappa statistics.

Result

The level of both mean inter-observer (K =0.322; 95%CI: 0.321–0.323) and intra-observer agreement (K =0.317; 95%CI: 0.314–0.320) in AO intertrochanteric fracture classification subgrouping were not satisfactory. The inter-observer (K =0.61; 95%CI: 0.608–0.611) and intra-observers' (K=0.560; 95%CI: 0.544–0.566) reliability in AO main groupings showed moderate agreement.

Conclusion

The AO classification does not show adequate and acceptable inter-observer and intra-observer reliability and reproducibility. Therefore, it will be hard to base on the AO classification for treatment protocols.

Evaluation of the Reproducibility of Lauge-Hansen, Danis-Weber, and AO Classifications for Ankle Fractures

Objective  The present study aims to analyze the intra- and interobserver reproducibility of the Lauge-Hansen, Danis-Weber, and Arbeitsgemeinschaft für Osteosynthesefragen (AO) classifications for ankle fractures, and the influence of evaluators training stage in these assessments. Methods  Anteroposterior (AP), lateral and true AP radiographs from 30 patients with ankle fractures were selected. All images were evaluated by 11 evaluators at different stages of professional training (5 residents and 6 orthopedic surgeons), at 2 different times. Intra- and interobserver agreement was analyzed using the weighted Kappa coefficient. Student t-tests for paired samples were applied to detect significant differences in the degree of interobserver agreement between instruments. Results  Intraobserver analysis alone had a significant agreement in all classifications. Moderate to excellent interobserver agreement was highly significant ( p  ≤ 0.0001) for the Danis-Weber classification. The Danis-Weber classification showed, on average, a significantly higher degree of agreement than the remaining classification systems ( p  ≤ 0.0001). Conclusion  The Danis-Weber classification presented the highest reproducibility among instruments and the evaluator's little experience had no negative influence on the reproducibility of ankle fracture classifications. Level of Evidence II, Diagnostic Studies - Investigating a Diagnostic Test .

A pilot agreement study of a new classification system for Peri-implant femoral fractures

BACKGROUND

Peri-implant fractures occur in association with an implant, used to treat a previous injury that is still attached to the bone. We recently published a proposal for a classification system for peri-implant femoral fractures [Videla-Cés, Injury,2019].

AIM

To assess the agreement of our classification system for peri-implant femoral fractures among a group of future users of said classification system.

METHODS

A prospective, multicentre, international agreement pilot study was conducted among a group of independent traumatologists/orthopaedic surgeons (evaluators): senior (a minimum of 10 years' experience) and junior (in fourth or fifth training year). A set of 30 radiographs of peri-implant femoral fractures were selected (stratified into 3 levels of difficulty: low, medium and high). Each evaluator interpreted the radiographs on 2 different occasions separated by a period of one month and in a different order each time. The level of difficulty was masked from the evaluators and they had one week to classify the radiographs each time. Logistic regression and Cohen's kappa coefficient (κ) and its 95% confidence interval (95%CI) were used to assess the accuracy and agreement, both intra- and inter-evaluator. Between senior and junior surgeons was performed an exploratory analysis.

RESULTS

35 traumatologists/orthopaedic surgeons (17 senior and 18 junior) from 16 tertiary hospitals from 4 countries acted as evaluators. The accuracy, percentage of correct classifications (2 digits and 3 letters), in the first and second evaluation was: 56% (95%CI: 53-59%) and 55% (95%CI: 51-57%), respectively. (insert space) Negligible differences were found between junior and senior evaluators (first evaluation, OR: 1.46, 95%CI: 0.82-2.61, p-value: 0.199; second evaluation, OR: 1.06, 95%CI: 0.56-2.00, p-value: 0.860). (insert space) Both medium and low radiograph difficulty were associated with a lower probability of an incorrect classification compared with those of high difficulty (first evaluation, OR: 7.60, 95%CI: 5.24-11.05, p-value: <0.001; OR: 14.15, 95%CI: 9.12-21.96, p-value: <0.001, respectively; second evaluation, OR: 7.11, 95%CI: 4.88-10.38, p-value: <0.001, OR: 15.28, 95%CI: 9.77-23.89, p-value: <0.001). (insert space) The kappa for intra-observer agreement between the first and second evaluation was: 0.66, 95%CI: 0.63, 0.69. The kappa for inter-observer agreement considering all 30 radiographs was: 0.40, 95%CI: 0.40, 0.41 in the first evaluation and 0.39, 95%CI: 0.39, 0.40 in the second evaluation.

CONCLUSION

The proposed classification for peri-implant femoral fractures may be useful and user-friendly. Future studies are needed to assess the how clinically useful this classification system may be (the third phase in the validation process).

Validity of classification of distal radial fractures in the Swedish fracture register

Background

Distal radial fractures (DRF) are one of the most common fractures with a small peak in incidence among young males and an increasing incidence with age among women. The reliable classification of fractures is important, as classification provides a framework for communicating effectively on clinical cases. Fracture classification is also a prerequisite for data collection in national quality registers and for clinical research. Since its inception in 2011, the Swedish Fracture Register (SFR) has collected data on more than 490,000 fractures. The attending physician classifies the fracture according to the AO/OTA classification upon registration in the SFR. Previous studies regarding the classification of distal radial fractures (DRF) have shown difficulties in inter- and intra-observer agreement. This study aims to assess the accuracy of the registration of DRF in adults in the SFR as it is carried out in clinical practice.

Methods

A reference group of three experienced orthopaedic trauma surgeons classified 128 DRFs, randomly retrieved from the SFR, at two classification sessions 6 weeks apart. The classification the reference group agreed on was regarded as the gold standard classification for each fracture. The accuracy of the classification in the SFR was defined as the agreement between the gold standard classification and the classification in the SFR. Inter- and intra-observer agreement was evaluated and the degree of agreement was calculated as Cohen’s kappa.

Results

The accuracy of the classification of DRF in the SFR was kappa = 0.41 (0.31–0.51) for the AO/OTA subgroup/group and kappa = 0.48 (0.36–0.61) for the AO/OTA type. This corresponds to moderate agreement. Inter-observer agreement ranged from kappa 0.22–0.48 for the AO/OTA subgroup/group and kappa 0.48–0.76 for the AO/OTA type. Intra-observer agreement ranged from kappa 0.52–0.70 for the AO/OTA subgroup/group and kappa 0.71–0.76 for the AO/OTA type.

Conclusions

The study shows moderate accuracy in the classification of DRF in the SFR. Although the degree of accuracy for DRF appears to be lower than for other fracture locations, the accuracy shown in the current study is similar to that in previous studies of DRF.

Independent Reliability Analysis of a New Classification for Pyogenic Spondylodiscitis

STUDY DESIGN

Diagnostic study, level of evidence III.

OBJECTIVE

Pyogenic spondylodiscitis can cause deformity, neurological compromise, disability, and death. Recently, a new classification of spondylodiscitis based on magnetic resonance imaging was published. The objective of this study is to perform an independent reliability analysis of this new classification.

METHODS

We selected 35 cases from our database of different spine centers in Latin America and from the literature; 8 observers evaluated the classification and graded the scenarios according to the methodological grading of the classification developed by Pola et al. Cases were sent to the observers in a random sequence after 3 weeks to assess intraobserver reliability. The interobserver and intraobserver reliabilities were performed with Fleiss and Cohen statistics, respectively.

RESULTS

The overall Fleiss κ value for interobserver agreement was substantial, with 0.67 (95% CI = 0.43-0.91) in the first reading and 0.67 (95% CI = 0.45-0.89) in second reading for the main types of classification. The Cohen κ value for intraobserver agreement was also substantial, with 0.68 (95% CI = 0.45-0.92). The interobserver agreement analysis for the subtypes of this classification was overall substantial, with 0.60 (95% CI = 0.37-0.83) in the first reading and 0.61 (95% CI = 0.41-0.81) in the second reading. The overall intraobserver agreement for subtypes of the classification was also substantial, with 0.63 (95% CI = 0.34-0.93).

CONCLUSION

The new classification developed by Pola et al showed substantial interobserver and intraobserver agreements. More studies are required to validate the usefulness of this classification especially in clinical practice.

Sample sizes of prediction model studies in prostate cancer were rarely justified and often insufficient

OBJECTIVE

Developing clinical prediction models (CPMs) on data of sufficient sample size is critical to help minimize overfitting. Using prostate cancer as a clinical exemplar, we aimed to investigate to what extent existing CPMs adhere to recent formal sample size criteria, or historic rules of thumb of events per predictor parameter (EPP)≥10.

STUDY DESIGN AND SETTING

A systematic review to identify CPMs related to prostate cancer, which provided enough information to calculate minimum sample size. We compared the reported sample size of each CPM against the traditional 10 EPP rule of thumb and formal sample size criteria.

RESULTS

About 211 CPMs were included. Three of the studies justified the sample size used, mostly using EPP rules of thumb. Overall, 69% of the CPMs were derived on sample sizes that surpassed the traditional EPP≥10 rule of thumb, but only 48% surpassed recent formal sample size criteria. For most CPMs, the required sample size based on formal criteria was higher than the sample sizes to surpass 10 EPP.

CONCLUSION

Few of the CPMs included in this study justified their sample size, with most justifications being based on EPP. This study shows that, in real-world data sets, adhering to the classic EPP rules of thumb is insufficient to adhere to recent formal sample size criteria.

COSMIN Risk of Bias tool to assess the quality of studies on reliability or measurement error of outcome measurement instruments: a Delphi study

BACKGROUND

Scores on an outcome measurement instrument depend on the type and settings of the instrument used, how instructions are given to patients, how professionals administer and score the instrument, etc. The impact of all these sources of variation on scores can be assessed in studies on reliability and measurement error, if properly designed and analyzed. The aim of this study was to develop standards to assess the quality of studies on reliability and measurement error of clinician-reported outcome measurement instruments, performance-based outcome measurement instrument, and laboratory values.

METHODS

We conducted a 3-round Delphi study involving 52 panelists.

RESULTS

Consensus was reached on how a comprehensive research question can be deduced from the design of a reliability study to determine how the results of a study inform us about the quality of the outcome measurement instrument at issue. Consensus was reached on components of outcome measurement instruments, i.e. the potential sources of variation. Next, we reached consensus on standards on design requirements (n = 5), standards on preferred statistical methods for reliability (n = 3) and measurement error (n = 2), and their ratings on a four-point scale. There was one term for a component and one rating of one standard on which no consensus was reached, and therefore required a decision by the steering committee.

CONCLUSION

We developed a tool that enables researchers with and without thorough knowledge on measurement properties to assess the quality of a study on reliability and measurement error of outcome measurement instruments.

Pediatric Femoral Shaft Fracture: An Age-Based Treatment Algorithm

PURPOSE

Fractures of the femoral shaft in children are common. The rates of bone growth and remodeling in children vary according to their ages, which affect their respective management.

METHODS

This paper evaluates the incidence and patterns of pediatric femoral shaft fracture and the current concepts of treatments available.

RESULTS

The type of fracture-closed or open; stable or unstable-needs to be taken into account. Child abuse should be suspected in fractures sustained by infants. For younger children, non-surgical management is preferred, which include Pavlik harness (< 6 months old) and early spica casting (6 months to 6 years old). Older children (> 6 years old) usually benefit from surgical treatments as outcomes of non-surgical alternatives are worse and are associated with prolonged recovery times. These operative measures for older children that are 6-12 years old include elastic stable intramedullary nailing and submuscular plating. Factors to be considered when devising an appropriate intervention include body mass, location of injury, and nature of fracture. For adolescent and skeletally mature teenagers (> 12 years old), rigid antegrade entry intramedullary fixation is indicated. In the event of open fractures or polytrauma, external fixation should be considered as a temporary treatment method for initial fracture stabilization.

CONCLUSION

An age-based and evidence-based algorithm has been proposed to guide surgeons in the process of evaluating an appropriate treatment.

A new classification of impacted proximal humerus fractures based on the morpho-volumetric evaluation of humeral head bone loss with a 3D model

BACKGROUND

This study aimed to classify the pathomorphology of impacted proximal humeral fractures according to the control volume theory, with the intention to introduce a severity index to support surgeons in decision making.

METHODS

In total, 50 proximal humeral fractures were randomly selected from 200 medical records of adult patients treated from 2009 to 2016. Four nonindependent observers used 2 different imaging modalities (computed tomography scans plus volume rendering; 3D model) to test the classification reliability. A fracture classification system was created according to the control volume theory to provide simple and understandable patterns that would help surgeons make quick assessments. The impacted fractures table was generated based on an evaluation of the calcar condition, determined by the impairment of a defined volumetric area under the cephalic cup and the humeral head malposition. In addition to the main fracture pattern, the comminution degree (low, medium, high), providing important information on fracture severity, could also be evaluated.

RESULTS

From 3D imaging, the inter- and intraobserver reliability revealed a k value (95% confidence interval) of 0.55 (0.50-0.60) and 0.91 (0.79-1.00), respectively, for the pattern code, and 0.52 (0.43-0.76) and 0.91 (0.56-0.96), respectively, for the comminution degree.

CONCLUSIONS

The new classification provides a useful synoptic framework for identifying complex fracture patterns. It can provide the surgeon with useful information for fracture analysis and may represent a good starting point for an automated system.

Reliability and validity of the Wrightington classification of elbow fracture-dislocation

Aims

The Wrightington classification system of fracture-dislocations of the elbow divides these injuries into six subtypes depending on the involvement of the coronoid and the radial head. The aim of this study was to assess the reliability and reproducibility of this classification system.

Methods

This was a blinded study using radiographs and CT scans of 48 consecutive patients managed according to the Wrightington classification system between 2010 and 2018. Four trauma and orthopaedic consultants, two post CCT fellows, and one speciality registrar based in the UK classified the injuries. The seven observers reviewed preoperative radiographs and CT scans twice, with a minimum four-week interval. Radiographs and CT scans were reviewed separately. Inter- and intraobserver reliability were calculated using Fleiss and Cohen kappa coefficients. The Landis and Koch criteria were used to interpret the strength of the kappa values. Validity was assessed by calculating the percentage agreement against intraoperative findings.

Results

Of the 48 patients, three (6%) had type A injury, 11 (23%) type B, 16 (33%) type B+, 16 (33%) Type C, two (4%) type D+, and none had a type D injury. All 48 patients had anteroposterior (AP) and lateral radiographs, 44 had 2D CT scans, and 39 had 3D reconstructions. The interobserver reliability kappa value was 0.52 for radiographs, 0.71 for 2D CT scans, and 0.73 for a combination of 2D and 3D reconstruction CT scans. The median intraobserver reliability was 0.75 (interquartile range (IQR) 0.62 to 0.79) for radiographs, 0.77 (IQR 0.73 to 0.94) for 2D CT scans, and 0.89 (IQR 0.77 to 0.93) for the combination of 2D and 3D reconstruction. Validity analysis showed that accuracy significantly improved when using CT scans (p = 0.018 and p = 0.028 respectively).

Conclusion

The Wrightington classification system is a reliable and valid method of classifying fracture-dislocations of the elbow. CT scans are significantly more accurate than radiographs when identifying the pattern of injury, with good intra- and interobserver reproducibility. Cite this article: Bone Joint J 2020;102-B(8):1041–1047.

Reliability and reproducibility of the new AO/OTA 2018 classification system for proximal humeral fractures: a comparison of three different classification systems

BACKGROUND

The classification systems for proximal humeral fractures routinely used in clinical practice include the Neer and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 2007 systems. Currently used systems have low inter- and intraobserver reliability. In 2018, AO/OTA introduced a new classification system with the aim of simplifying the coding process, in which the Neer four-part classification was integrated into the fracture description. The aim of the present work is to assess the inter- and intraobserver agreement of the new AO/OTA 2018 compared with the Neer and AO/OTA 2007 classifications.

MATERIALS AND METHODS

A total of 116 radiographs of consecutive patients with proximal humeral fracture were selected and classified by three observers with different levels of experience. All three observers independently reviewed and classified the images according to the Neer, AO/OTA 2007, and new AO/OTA 2018 systems. To determine the intraobserver agreement, the observers reviewed the same set of radiographs after an interval of 8 weeks. The inter- and intraobserver agreement were determined through Cohen's kappa coefficient analysis.

RESULTS

The new AO/OTA 2018 classification showed substantial mean inter- (k = 0.67) and intraobserver (k = 0.75) agreement. These results are similar to the reliability observed for the Neer classification (interobserver, k = 0.67; intraobserver, k = 0.85) but better than those found for the AO/OTA 2007 system, which showed only moderate inter- (k = 0.57) and intraobserver (k = 0.58) agreement. The two more experienced observers showed better overall agreement, but no statistically significant difference was found. No differences were found between surgical experience and agreement regarding specific fracture types or groups.

CONCLUSIONS

The results showed that the Neer system still represents the more reliable and reproducible classification. However, the new AO/OTA 2018 classification improved the agreement among observers compared with the AO/OTA 2007 system, while still maintaining substantial descriptive power and simplifying the coding process. The universal modifiers and qualifications, despite their possible complexity, allowed a more comprehensive fracture definition without negatively affecting the reliability or reproducibility of the classification system.

LEVEL OF EVIDENCE

Level III, diagnostic studies.

A New Classification System for Pilon Fractures Based on CT Scan: An Independent Interobserver and Intraobserver Agreement Evaluation

BACKGROUND DATA

A new pilon fracture classification system based on CT scan data was recently published, showing almost perfect interobserver and intraobserver agreement among the authors who developed it. However, an independent assessment has not been done.

OBJECTIVE

To do an independent agreement evaluation of the new pilon fracture classification system with physicians with different levels of expertise in the management of pilon fractures.

METHODS

Seventy-one cases of acute pilon fracture were retrospectively collected. Fractures were classified by six evaluators (three foot and ankle surgeons and three orthopaedic surgery residents) using CT scans according to the morphological grading of the new pilon fracture classification system developed by Leonetti et al. Cases were presented to the same evaluators in a random sequence after a 6-week interval to determine intraobserver agreement. The kappa coefficient (κ) was used to determine agreement among evaluators.

RESULTS

The interobserver agreement was substantial regarding the main fracture type (I, II, III, or IV), with an overall κ value of 0.69 (0.65 to 0.72). When including the II and III subtypes, the overall agreement was still substantial, with a κ value of 0.61 (95% confidence interval: 0.58 to 0.64). The intraobserver agreement was substantial when considering the main fracture categories (I, II, III, or IV), with a κ value of 0.78 (confidence interval: 0.72 to 0.84), and full agreement at the type level was observed in 76% (324/426) of evaluations. There was no notable difference between the foot and ankle surgeons and orthopaedic surgery residents in the interobserver and intraobserver agreement.

CONCLUSION

The new classification system demonstrated substantial interobserver and intraobserver agreement between evaluators with different levels of expertise in the management of pilon fractures. Prospective studies should be done to evaluate its prognostic value and utility in clinical practice.

Multiple rib fractures: A novel and prognostic CT-based classification system

Background

The accepted classification for multiple rib fractures is binary: flail chest or not. There is a wide spectrum of morphology with subsequent variation in the impact on chest wall mechanics and clinical outcomes. As the practice of surgical stabilisation of rib fractures evolves, there is a need for a better taxonomy. The aim of this study was to create a data-driven radiological classification system for multiple rib fractures, prognostic of both complications and surgical stabilisation of rib fracture.

Methods

The radiological pattern of injury was assessed for cases undergoing surgical stabilisation of rib fracture (n = 48) over a five-year period and a consecutive sample of non-operative controls (n = 48). Every rib fracture (n = 1032) was assessed on CT scans for location, displacement and comminution. An iterative classification system was developed and tested for inter-observer agreement and outcome prediction.

Results

The fractures occurred in a ‘series’ (≥3 consecutive ribs at a similar location) in 72% of cases: these were more likely to be displaced (p < 0.001). Variables included in the classification were the anatomical pattern (presence, length and overlap of series) and degree of displacement. The classification was prognostic for complications (p < 0.001), discriminated for fixation (C = 0.907) and had acceptable inter-observer agreement (k = 0.50).

Conclusions

The Sheffield Multiple Rib Fracture Classification derived categories of short/long series, and short/long flail chest, with sub-division according to the presence of displacement. It was prognostic for clinical outcomes and of surgical fixation. It may facilitate communication, comparison of outcomes and selection for management protocols.

The effects of soft tissue lateral release on the stability of the ligament complex of the knee

PURPOSE

Valgus deformity presents a particular challenge in total knee arthroplasty. This condition regularly leads to contractures of the lateral capsular ligament complex and to overstretching of the medial ligamentous complex. Reconstruction of the knee joint kinematics and anatomy often requires lateral release. However, data on how such release weakens the stability of the knee are missing in the literature. This study investigated the effects of sequential lateral release on the collateral stability of the ligament complex of the knee in vitro.

METHODS

Ten knee prostheses were implanted in 10 healthy cadaveric knee joints using a navigation device. Soft tissue lateral release consisted of five release steps, and stiffness and stability were determined at 0, 30, 60 and 90° flexion after each step.

RESULTS

Soft tissue lateral release increasingly weakened the ligament complex of the lateral compartment. Because of the large muscular parts, the release of the iliotibial band and the M. popliteus had little effect on the stability of the lateral and medial compartment, but release of the lateral ligament significantly decreased the stability in the lateral compartment over the entire range of motion. Stability in the medial compartment was hardly affected. Conversely, further release of the posterolateral capsule and the posterior cruciate ligament led to the loss of stability in the lateral compartment only in deep flexion, whereas stability decreased significantly in the medial compartment.

CONCLUSION

Our study shows for the first time the association between sequential lateral release and stability of the ligamentous complex of the knee. To maintain the stability, knee surgeons should avoid releasing the entire lateral collateral ligament, which would significantly decrease stability in the lateral compartment.

Pyogenic spondylodiscitis : The quest towards a clinical-radiological classification

BACKGROUND

Pyogenic spondylodiscitis (PS) is a debilitating condition laden with orthopedic and neurological complications. The choice of the best step in management is often delayed due to the controversy encompassing its multiple facets. Several classification systems were proposed in the literature to define optimal management; however, consensus was not achieved.

OBJECTIVE

The aim of this study was to review the literature and critically appraise the classification systems of PS and the rationale behind the classification criteria.

METHODS

A literature search was conducted in PubMed. Titles and abstracts of articles were searched using different synonyms of spondylodiscitis and its classification. No restrictions regarding language of publication or date of publication were applied.

RESULTS

A total of 43 papers with 5 encompassing 3 main classifications were found in the literature. These classifications were overlapping but different. They encompassed neurologic deficits, abscess formation and segmental instability, laboratory parameters and morphological changes in magnetic resonance imaging (MRI) as the most important factors used to classify PS, assess the severity and guide treatment.

CONCLUSION

The current classification schemes overlap and encompass the most clinically relevant factors; however, some could be too complex for interdisciplinary clinical practice and do not adequately address unique entities, such as PS of the cervical spine, anterolisthesis and retrolisthesis. Most importantly, some criteria must be utilized in concert with recently published guidelines and should be re-assessed for validity and reliability. A uniform orthopedic parlance is required to optimize the management of this debilitating and life-threatening condition.

Interpreting and reporting fracture classification and operation type in hip fracture

Aims

This study explores data quality in operation type and fracture classification recorded as part of a large research study and a national audit with an independent review.

Patients and Methods

At 17 centres, an expert surgeon reviewed a randomly selected subset of cases from their centre with regard to fracture classification using the AO system and type of operation performed. Agreement for these variables was then compared with the data collected during conduct of the World Hip Trauma Evaluation (WHiTE) cohort study. Both types of surgery and fracture classification were collapsed to identify the level of detail of reporting that achieved meaningful agreement. In the National Hip Fracture Database (NHFD), the types of operation and fracture classification were explored to identify the proportion of “highly improbable” combinations.

Results

The records were reviewed for 903 cases. Agreement for the subtypes of extracapsular fracture was poor; most centres achieved no better than “fair” agreement. When the classification was collapsed to a single option for “extracapsular” fracture, only four centres failed to have at least “moderate” agreement. There was only “moderate” agreement for the subtypes of intracapsular fracture, which improved to “substantial” when collapsed to “intracapsular”. Subtrochanteric fracture types were well reported with “substantial” agreement. There was near “perfect” agreement for internal fixation procedures. “Perfect” or “substantial” agreement was achieved when the type of arthroplasty surgery was reported at the level of “hemiarthroplasty” and “total hip replacement”. When reviewing data submitted to the NHFD, a minimum of 5.2% of cases contained “highly improbable” procedures for the stated fracture classification.

Conclusion

The complexity of collecting fracture classification data at a national scale compromises the accuracy with which detailed classification systems can be reported. Data around type of surgery performed show similar tendencies. Data capture, reporting, and interpretation in future studies must take this into account. Cite this article: Bone Joint J 2019;101-B:1292–1299

Weakening of the knee ligament complex due to sequential medial release in total knee arthroplasty

PURPOSE

The purpose of this study was to investigate the effects of sequential medial release on the stiffness and collateral stability of the ligament complex of the knee. Irrespective of the implantation technique used, varus deformity frequently requires release of the capsular ligament complex. Yet, no data are available on how stiffness and stability of the knee ligament complex are weakened by such release.

METHODS

After total knee arthroplasty, ten healthy Thiel-fixed knee joints were subjected to sequential medial release consisting of six release steps. After each step, stiffness and stability were determined at 0°, 30°, 60°, and 90°.

RESULTS

Sequential medial release increasingly weakened the ligament complex. In extension, release of the anteromedial tibial sleeve 4 cm below the joint line already weakened the ligament complex by approximately 13%. Release 6 cm below the joint line reduced stiffness and stability by 15-20% over the entire range of motion. After detachment of the medial collateral ligament, stability was only about 60% of its initial value.

CONCLUSION

Our study showed for the first time the association between medial release and stiffness and stability of the knee ligament complex. To maintain stability, vigorous detachment of the knee ligament complex should be avoided. Release of the anteromedial tibial sleeve already initiates loss of stability. The main stabiliser is the medial ligament, which should never be completely detached.

LEVEL OF EVIDENCE

IV.

Fragility Fractures of the Pelvis Classification: A Multicenter Assessment of the Intra-Rater and Inter-Rater Reliabilities and Percentage of Agreement

BACKGROUND

The fragility fractures of the pelvis (FFP) classification was established to address the specific fracture morphology and dynamic instability in the elderly. Although this system is frequently used, data on the intra-rater and inter-rater reliabilities are lacking.

METHODS

Six experienced and 6 inexperienced surgeons and 1 surgeon trained by the originator of the FFP classification ("gold standard") each used the FFP classification 3 times to grade the computed tomography (CT) scans of 60 patients from 6 hospitals. We assessed intra-rater and inter-rater reliabilities using Fleiss kappa statistics and the percentage of agreement using the "gold standard," the submitting hospital, and the majority vote as references.

RESULTS

The intra-rater reliability for the FFP classification was mainly moderate, with a mean Fleiss kappa coefficient (and 95% confidence interval) of 0.46 (0.40 to 0.50) for the complete classification (i.e., both the main-group FFP ratings [I through III] and the subgroup ratings [a, b, and c]) and 0.60 (0.53 to 0.65) for the main group only. The inter-rater reliability was substantial for the main group classification (0.61 [0.54 to 0.66]) and moderate for the complete classification (0.53 [0.48 to 0.58]). The percentage of agreement was 68% to 80%. The lowest agreement was found for FFP II and III.

CONCLUSIONS

The FFP classification displayed moderate and substantial intra-rater and inter-rater reliabilities.

CLINICAL RELEVANCE

With moderate to substantial intra-rater and inter-rater reliabilities, the FFP classification forms a solid basis for future clinical investigations. The differentiation of FFP II from FFP III should be evaluated thoroughly, as the initial treatment changes from nonoperative for II to operative for III.

Femoral fracture classification in the Swedish Fracture Register - a validity study

Background

A total of more than 270,000 fractures are registered in the Swedish Fracture Register (SFR), a national quality register. Fractures are classified following the AO/OTA classification, commonly by a junior doctor. As a step in the process of validating the data in the SFR, several studies of the accuracy of the fracture classification have already been published. The aim of this study was to evaluate the accuracy of femoral fracture classification in the SFR.

Methods

One hundred and eighteen femur fractures were randomly selected from the SFR. Three experienced orthopaedic surgeons individually classified these fractures on two separate occasions and a gold standard classification was established. This classification was compared with the original classification in the SFR. Inter- and intraobserver agreement was calculated.

Results

The agreement between the classification in the SFR and the gold standard classification was kappa = 0.65 for the AO/OTA group and kappa = 0.83 for the AO/OTA type. This corresponds to substantial and almost perfect agreement, according to Landis and Koch. The kappa values for interobserver agreement ranged from 0.64–0.76 for the AO/OTA group and 0.76–0.85 for the AO/OTA type. The kappa values for intraobserver agreement ranged from 0.79–0.81 for the AO/OTA group and 0.91–0.93 for the AO/OTA type.

Conclusions

The classification of femoral fractures in the Swedish Fracture Register is substantial (AO/OTA group) to almost perfect (AO/OTA type) and as accurate as in previous studies. The present study also shows that the agreement between the SFR classification and a gold standard classification is in the same range of agreement as between experienced raters. In contrast to previous studies, the classifications in the SFR are made by an unselected group of mostly inexperienced classifiers. The results indicate that the fracture classification in a national quality register can be accurate enough to permit the evaluation of fracture treatment in specific groups of fractures.

Reliability and Validity of the AOSpine Thoracolumbar Injury Classification System: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

The AOSpine thoracolumbar injury classification system (ATLICS) is a relatively simple yet comprehensive classification of spine injuries introduced in 2013. This systematic review summarizes the evidence on measurement properties of this new classification, particularly the reliability and validity of the main morphologic injury types with and without inclusion of the subtypes.

METHODS

A literature search was performed using PubMed and Embase in September 2016. A revised version of the COSMIN checklist was used for evaluation of the quality of studies. Two independent reviewers performed all steps of the review.

RESULTS

Nine articles were included in the final review, all of which evaluated the reliability of the ATLICS and had a fair methodological quality. The reliability of the modifiers was unknown. Overall, the quality of evidence for reliability of the morphologic and neurologic classification sections was low. However, there was moderate evidence for poor interobserver reliability of the morphologic classification when all subtypes were included, and moderate evidence for good intraobserver reliability with exclusion of subtypes. The reliability of the morphologic classification was independent of the observer's experience and cultural background.

CONCLUSIONS

ATLICS represents the most current system for evaluation of thoracolumbar injuries. Based on this review, further studies with robust methodological quality are needed to evaluate the measurement properties of ATLICS. Shortcomings of the reliability studies are discussed.

Proposal for the classification of peri-implant femoral fractures: Retrospective cohort study

Background Peri-implant fractures occur in association with an implant used to treat a previous injury and that is still attached to the bone. Peri-implant fractures are considered to be relatively "new" fractures and they lack any classification system that is accepted in practice. Generally, the fracture classification systems currently used in our clinical practice were not developed or validated using rigorous scientific evaluation methods. Aim To provide data for a proposed classification of peri-implant femoral fractures. Methods This is an international and multicentre study (12 centres) based on a cohort of consecutive peri-implant fractures with the criterion being: a fracture in any segment of the femur in association with previously-used osteosynthesis material, whether a nail, plate or screws. A proposed system for the classification was tested, based on a topographical classification using alphanumeric coding, following a similar nomenclature to that explained in the "Vancouver-Classification-for-Total-Hip-Arthroplasty-Periprosthetic-Fractures", and classified according to whether the implant is a nail, a screw or a plate, and the location of the fracture in relation to the original implant and the affected femoral segment. The study coordinator performed the first classification exercise, which was discussed subsequently for the study coordinator group to reach a consensus. A descriptive analysis of the fractures was produced. The proportion of peri-implant femoral fractures was estimated, and 95% confidence interval (95%CI) was calculated. Results Between January 2013 and December 2016, data on a total of 143 peri-implant femoral fractures were collected. Only 5 (3.5%) fractures had to be discussed to reach a consensus. The most common peri-implant femoral fractures were located at the diaphyseal segment (#32) and associated with nails or plates: 51%, 73/143, 95%CI:43-59%; at the proximal segment (#31): 39%, 56/143, 95%CI:32-47%; and at the distal femoral segment (#33): 10%, 14/143, 95%CI:6-16%. The highest proportion of peri-implant femoral fractures corresponded to #31-AN (trochanteric and neck area) and #32-CNP (diaphysis fractures distant from the implant, often distal and spiral). Conclusion The proposed classification for peri-implant femoral fractures appears to be useful and easy to accomplish. Future studies will be necessary to validate it and demonstrate the effectiveness of its application in clinical practice.

Inter- and intra-rater reliability of vertebral fracture classifications in the Swedish fracture register

AIM

To investigate the inter- and intra-rater reliability of the vertebral fracture classifications used in the Swedish fracture register.

METHODS

Radiological images of consecutive patients with cervical spine fractures (n = 50) were classified by 5 raters with different experience levels at two occasions. An identical process was performed with thoracolumbar fractures (n = 50). Cohen’s kappa was used to calculate the inter- and intra-rater reliability.

RESULTS

The mean kappa coefficient for inter-rater reliability ranged between 0.54 and 0.79 for the cervical fracture classifications, between 0.51 and 0.72 for the thoracolumbar classifications (overall and for different sub classifications), and between 0.65 and 0.77 for the presence or absence of signs of ankylosing disorder in the fracture area. The mean kappa coefficient for intra-rater reliability ranged between 0.58 and 0.80 for the cervical fracture classifications, between 0.46 and 0.68 for the thoracolumbar fracture classifications (overall and for different sub classifications) and between 0.79 and 0.81 for the presence or absence of signs of ankylosing disorder in the fracture area.

CONCLUSION

The classifications used in the Swedish fracture register for vertebral fractures have an acceptable inter- and intra-rater reliability with a moderate strength of agreement.

Epidemiology of Adult Ankle Fractures: 1756 cases identified in Norrbotten County during 2009-2013 and classified according to AO/OTA

Background

The ankle fracture is one of the most common fractures, increasing in an ageing population, but not generally seen as an osteoporotic fracture. The aim of this study was to examine the relationship between different AO/OTA classes of ankle fractures, age, sex and type of trauma.

Methods

Ankle fractures, treated at any of the hospitals in Norrbotten County in Sweden between 2009 and 2013, were retrospectively identified and classified according to the AO/OTA-classification system. Information about the trauma mechanism was also obtained.

Results

In Norrbotten County, 1756 ankle fractures in 1735 patients aged 20 years or older were identified. This gave an incidence in the county of 179 per 100,000 person-years. Of these patients, 34.6% were 65 years or older, 58.4% were women and 68.2% of the trauma leading to a fracture was defined as low-energy. In 1.5% of the cases the fractures were open. Incidences of type B fractures increased substantially with age, from 62 (95% CI 50–77) at 30–39 years of age to 158 (95% CI 131–190) in patients older than 80 years of age per 100,000 person-years. Type B fractures showed a slightly higher proportion of low-energy trauma while type C showed a lower mean age and proportion of women.

Conclusions

This study shows an incidence of 179 adult ankle fractures annually per 100,000 persons. More than two thirds of the fractures were caused by a low-energy trauma and ankle fractures are more frequent among females. Females generally have an increased incidence during their life, mainly between the ages of 30 and 60. This is in contrast to men who have more of an even distribution throughout their life. Classification according to AO/OTA reveals some heterogeneity among the classes of ankle fractures in age and gender as well as the energy involved in the trauma.

Development and Validation of the Foot Union Scoring Evaluation Tool for Arthrodesis of Foot Structures

Reliable evaluation of osseous consolidation after pedal arthrodesis can be difficult, and the presence or absence of radiographic healing often dictates care. Plain radiographs remain the mainstay imaging tool owing to their cost, efficiency, and low radiation exposure. Applying radiographic parameters that can reliably determine osseous healing is essential. However, currently, no reliable or validated measures are available to determine osseous union of any joint in the foot or ankle. The purpose of the present study was to develop a radiographic healing scoring system that would enhance the diagnostic healing assessment after joint arthrodesis of the foot or ankle. We adapted several existing scales previously validated for fracture healing in the leg, because no study has attempted to apply this to a joint fusion model. A total of 150 cases were evaluated by 6 blinded assessors to test the interrater reliability of the subjective healing assessment compared with the proposed scoring system. The radiographs were classified by the postoperative period: ≤4 weeks, 5 to 12 weeks, and >12 weeks. The initial proposed scale was found to have high interrater reliability but was burdensome. Using a priori item reduction protocols, a limited 5-item scale further improved the internal consistency and reduced the burden. The result was excellent interrater reliability (α = 0.978, standard deviation 0.02, 95% confidence interval 0.96 to 0.99) among all assessors compared with the reduced reliability (α = 0.752) for subjective arthrodesis healing. Intrarater reliability was also found to be superior using a test-retest method. The reliability of this system appeared superior to the subjective assessment of arthrodesis healing, even in the absence of clinical correlates, after foot arthrodesis.

Customized implants for acetabular Paprosky III defects may be positioned with high accuracy in revision hip arthroplasty

PURPOSE

In revision hip arthroplasty, custom-made implants are one option in patients with acetabular Paprosky III defects.

METHODS

In a retrospective analysis, we identified 11 patients undergoing cup revision using a custom-made implant. The accuracy of the intended position of the implant was assessed on post-operative 3D CT and compared to the pre-operative 3D planning in terms of inclination, anteversion, and centre of rotation. In addition, the accuracy of post-operative plain radiographs for measuring implant position was evaluated in relation to the 3D CT standard.

RESULTS

We found a mean deviation between the planned and the final position of the custom-made acetabular implant on 3D CT of 3.6° ± 2.8° for inclination and of - 1.2° ± 7.0° for anteversion, respectively. Restoration of center of rotation succeeded with an accuracy of 0.3 mm ± 3.9 mm in the mediolateral (x) direction, - 1.1 mm ± 3.8 mm in the anteroposterior (y) direction, and 0.4 mm ± 3.2 mm in the craniocaudal (z) direction. The accuracy of the post-operative plain radiographs in measuring the position of the custom-made implant in relation to 3D CT was 1.1° ± 1.7° for implant inclination, - 2.6° ± 1.3° for anteversion and 1.3 mm ± 3.5 mm in the x-direction, and - 0.9 mm ± 3.8 mm in the z-direction for centre of rotation.

CONCLUSION

Custom-made acetabular implants can be positioned with good accuracy in Paprosky III defects according to the pre-operative planning. Plain radiographs are adequate for assessing implant position in routine follow-up.

Radiographic Union Scoring Scale for Determining Consolidation Rates in the Calcaneus

The reliable evaluation of osseous consolidation after hindfoot osteotomy can be difficult. Concomitant hindfoot osteotomies often dictate the advancement of weightbearing, and radiographs are the mainstay imaging tool owing to cost, efficiency, and radiation exposure. Understanding the radiographic parameters that can be used to reliably determine osseous healing is paramount. However, currently, no reliable or validated method is available to determine osseous healing of hindfoot osteotomies in irregular bones of the foot. The purpose of the present study was to develop a radiographic healing scoring system that would enhance the diagnostic healing assessment after elective calcaneal osteotomy. We adapted existing orthopedic scales validated for healing in the leg for application in the irregular bones of the foot. A total of 168 cases were evaluated by 6 blinded assessors to test the interrater reliability of subjective healing assessment compared with the proposed scoring system. The radiographs were classified by postoperative period: ≤4 weeks, 5 to 12 weeks, and >12 weeks. The proposed scale had high interrater reliability but was burdensome. Using a priori item reduction protocols, a limited 6-item scale further improved internal consistency and reduced the burden. The result was excellent interrater reliability (α = 0.98, standard deviation 0.02, 95% confidence interval 0.91 to 0.96) among all assessors when using the scoring scale compared with unacceptable reliability (α = 0.438) for subjective osteotomy healing. The reliability of our system appeared superior to that of subjective assessment of osseous healing alone, even in the absence of clinical correlates after osteotomy of the calcaneus.

Intraobserver and interobserver reproducibility of the old and new classifications of toracolombar fractures

Objective

To evaluate the inter and intraobserver agreement of the Magerl AO and AOSpine thoracolumbar fracture classification systems.

Methods

The participants were divided into two groups, the first composed of six spinal surgeons and the other composed of 18 medical orthopedic residents. On two different occasions, separated by an interval of one month, the participants analyzed and classified 25 radiographs with thoracolumbar fractures using both thoracolumbar fracture classification systems, Magerl AO and AOSpine. The results were analyzed for classification reliability using the Kappa coefficient (k).

Results

The Magerl AO classification system showed a fair interobserver agreement (k = 0.32), considering the fractures type and subtype, whereas the AOSpine classification system showed a moderate interobserver agreement (k = 0.59). The Magerl AO classification showed a fair intraobserver agreement for both residents and specialists (k = 0.21 and 0.38, respectively), while the AOSpine showed a substantial agreement between residents (k = 0.62) and moderate between specialists (k = 0.53).

Conclusions

When evaluating fracture morphology, the AOSpine thoracolumbar fracture classification system presented a better reliability and reproducibility compared to the Magerl AO classification system.

A systematic literature review of tibial plateau fractures: What classifications are used and how reliable and useful are they?

INTRODUCTION

Classification systems such as the Schatzker and AO/OTA have been proposed for standardised assessment of tibial plateau fractures and to guide clinical decision making. However, there has been no comprehensive literature review of all classification systems for tibial plateau fractures, including assessment of their reliability. The aim of this systematic review was to identify and appraise previously established classification systems for tibial plateau fractures and determine their reliability for fracture classification.

METHODS

Six databases were searched from inception until October 2016. Classification systems for tibial plateau fractures were identified. No restriction was placed on imaging modality (plain film X-ray, CT, MRI). Data synthesis was performed to identify common features of the systems, their prevalence within the literature and studies of intra and inter-rater reliability of fracture classification using Kappa coefficient (κ).

RESULTS

Thirty-eight classification systems were identified, five of which were a sub-classification of a single fracture type from a previous tool. The Schatzker and AO/OTA classification systems were the most commonly reported. Of the tools identified only five have been tested for inter and intra-observer reliability (Schatzker, AO/OTA, Duparc, Hohl and Luo). Reliability of more simplistic classification systems, such as that by Luo et al. (three-column) was typically high (intra-κ = 0.67-0.81, inter-κ = 0.71-0.87), but with the disadvantage of providing less information on fracture patterns and morphology. Intra and inter-observer reliability using plain film X-ray was frequently moderate (κ = 0.40-0.60), with 2D and 3D CT typically improving reliability of classification. Only 11 of the 32 complete classification systems identified association of fracture classification with clinical outcome.

DISCUSSION

Frequently used systems for classification of tibial plateau fractures display moderate intra and inter-observer reliability. More sophisticated imaging modalities such as 2D and 3D CT typically improve reliability estimates. Using fracture classification based on imaging findings to predict clinical outcome was not a commonly reported goal of newly developed systems. More detailed assessment of fracture patterns and morphology, in conjunction with information on surgical fixation, may be desirable for predicting outcomes and to guide clinical decision making.

Evaluation of interobserver agreement in Albertoni's classification for mallet finger

Objective

To measure the reliability of Albertoni's classification for mallet finger.

Methods

Agreement study. Forty-three radiographs of patients with mallet finger were assessed by 19 responders (12 hand surgeons and seven residents). Injuries were classified by Albertoni's classification. For agreement comparison, lesions were grouped as: (A) tendon avulsion; (B) avulsion fracture; (C) fracture of the dorsal lip; and (D) physis injury-and subgroups (each group divided into two subgroups). Agreement was assessed by Fleiss's modification for kappa statistics.

Results

Agreement was excellent for Group A (k = 0.95 (0.93-0.97)) and remained good when separated into A1 and A2. Group B was moderate (k = 0.42 (0.39-0.44)) and poor when separated into B1 and B2. In the Group C, agreement was good (k = 0.72 (0.70-0.74)), but when separated into C1 and C2, it became moderate. Group D was always poor (k = 0.16 (0.14-0.19)). The general agreement was moderate, with (k = 0.57 (0.56-0.58)).

Conclusion

Albertoni's classification evaluated for interobserver agreement is considered a reproducible classification by the method used in the research.