Neer's classification system: a critical appraisal

Stiffness changes in internal rotation muscles of the shoulder and its influence on hemiplegic shoulder pain

Background

Hemiplegic shoulder pain (HSP) is a common complication in patients with stroke. The pathogenesis of HSP is complex, and muscle hypertonia, especially the hypertonia of internal rotation muscles of the shoulder, may be one of the important causes of shoulder pain. However, the relationship between muscle stiffness and HSP has not been well studied. The purpose of this study is to explore the correlations between the stiffness of internal rotation muscles and clinical symptoms in patients with HSP.

Methods

A total of 20 HSP patients and 20 healthy controls were recruited for this study. The stiffness of internal rotation muscles was quantified using shear wave elastography, and Young's modulus (YM) of the pectoralis major (PM), anterior deltoid (AD), teres major ™, and latissimus dorsi (LD) were measured. Muscle hypertonia and pain intensity were evaluated using the Modified Ashworth Scale (MAS) and Visual Analog Scale (VAS), respectively. The mobility of the shoulder was evaluated using the Neer score. The correlations between muscle stiffness and the clinical scales were analyzed.

Results

YM of internal rotation muscles on the paretic side was higher than that of the control group in the resting and passive stretching positions (P < 0.05). YM of internal rotation muscles on the paretic side during passive stretching was significantly higher than that at rest (P < 0.05). YM of PM, TM, and LD during passive stretching were correlated with MAS (P < 0.05). In addition, the YM of TM during passive stretching was positively correlated with VAS and negatively correlated with the Neer score (P < 0.05).

Conclusion

Increased stiffness of PM, TM, and LD was observed in patients with HSP. The stiffness of TM was associated with pain intensity of the shoulder and shoulder mobility.

Operative choice for displaced proximal humeral fractures in adolescents with open visible physis: A comparative study of external fixator vs. Kirschner wire

BACKGROUND

For adolescents with severely displaced proximal humeral fracture (PHF), surgery is a good choice yielding excellent outcomes, and Kirchner wire (KW) is a cost-effective choice for fixation. Purpose of this study is to compare the clinical outcomes of external fixator (EF) and KW for the treatment of PHF in adolescents.

METHODS

Patients of PHF operated at our institute, from January 2008 to January 2016, were reviewed retrospectively. Demographic data, including sex, age at the time of surgery, operated side, and hardware choice, were collected from the hospital database. Preoperative radiographs were reviewed and classified according to Neer-Horwitz classification. Shoulder function was evaluated at the last follow-up using the American Shoulder and Elbow Surgeons (ASES) score. Complications, including infection, malunion, nonunion, stiffness of the shoulder joint, and failure of fixation were also recorded.

RESULTS

Thirty-five patients, including 23 males and 12 females, were included in the EF group, whereas 40 patients, including 25 males and 15 females, were included in the KW group (P = 0.867). The average age of patients in the EF group was 13.3 ± 1.7 years, and that of KW was 13.6 ± 1.8 years (P = 0.409). Patients in both groups were followed-up for at least 12 months. The operative time in the EF group (42.4 ± 11.2 min) was significantly shorter than those in the KW group (54 ± 13.6 min) (P < 0.001). The frequency of fluoroscopy in the EF group (12 ± 2.4 times) was significantly less than those in the KW group (17 ± 2.8 times (P < 0.001). The rate of open reduction was significantly higher in KW (35%) group than those in the EF group (0%) (P < 0.001). There was no case of nonunion and malunion in both groups.

CONCLUSION

External fixator is superior to Kirschner wire in the treatment of proximal humeral fractures in adolescents with shorter operative time and lower rate of open reduction with comparable clinical outcomes.

Reproducibility of the modified Neer classification defining displacement with respect to the humeral head fragment for proximal humeral fractures

Background

Although the Neer classification is widely used for the assessment of proximal humeral fractures, its reproducibility has been challenged. The purpose of this study was to evaluate the reproducibility of the conventional Neer classification and a modified classification that defined fracture displacement with respect to the humeral head fragment.

Methods

The fracture patterns in 80 cases of proximal humeral fractures were independently assessed by 6 observers. The cases were grouped according to the conventional Neer classification using radiographs followed by computed tomography (CT) scans by each examiner twice with a 1-month interval. The fractures were then classified with the modified Neer classification, which defined displacement of the fragment as separation of more than 1 cm or angulation of more than 45° from the humeral head fragment, twice with a 1-month interval. Kappa coefficients of the conventional and modified Neer classifications were compared.

Results

The modified classification showed significantly higher intra-observer agreement than the conventional classification, both for radiographs (P = .028) and for CT scans (P = .043). Intra-observer agreement was also significantly higher for the modified classification than for the conventional classification, both for radiographs (P = .001) and for CT scans (P < .001).

Conclusions

The present study showed that agreement for the Neer classification could be improved when fracture displacement was defined as separation or angulation from the humeral head. Considering vascularity to the humeral head, furthermore, the modified method might be more helpful for predicting patients’ prognosis than the conventional Neer classification.

Reliability of the Traditional Classification Systems for Acromioclavicular Joint Injuries by Radiography

Background

The present study aimed to examine the reliability of the radiographic classification systems for acromioclavicular (AC) joint injuries.

Methods

We initially polled 47 orthopaedic surgeons regarding what common technique they used for applying the Rockwood and the Tossy and Allman classification systems. All used a single standard AC joint view (Zanca view). We then presented 24 Zanca view radiographs of patients who had sustained AC joint injuries to 19 specialist shoulder surgeons and asked each of them to classify the injuries using the Rockwood and the Tossy and Allman classification systems. We then altered the order of radiographs and repeated the survey with the same group of surgeons 1 month later.

Results

The mean inter-observer agreement and the corresponding weighted kappa for the Rockwood and the Tossy and Allman classification system were 64.6% and 0.258; and 68.1% and 0.309, respectively. The mean intra-observer agreement and the corresponding weighted kappa for the systems were 59.4% and 0.150; and 67.4% and 0.113, respectively.

Conclusions

We conclude that the classification of AC joint injuries using a radiograph alone has limited reliability and consistency in clinical practice.

The Effect of Two Factors on Interobserver Reliability for Proximal Humeral Fractures

INTRODUCTION

The purpose of this study was to assess whether training observers and simplifying proximal humeral fracture classifications improve interobserver reliability among a large number of orthopaedic surgeons.

METHODS

One hundred eighty-five observers were randomized to receive training or no training in a simple classification for proximal humeral fractures before evaluating preoperative radiographs of a consecutive series of 30 patients who were treated with open reduction and internal fixation.

RESULTS

The overall interobserver reliability of the simple proximal humeral fracture classification system was low and not significantly different between the training and the no training group (κ = 0.20 and κ = 0.18, respectively; P = 0.10). Subgroup analyses showed that training improved the agreement among surgeons who have been in independent practice ≤5 years (κ = 0.23 versus κ = 0.14; P < 0.001), surgeons from the United States (κ = 0.23 versus κ = 0.16; P = 0.002), and general orthopaedic surgeons (κ = 0.42 versus κ = 0.15; P = 0.021).

DISCUSSION

Simplifying classifications and training observers did not improve the interobserver reliability for the diagnosis of proximal humeral fractures. However, training observers improved interobserver reliability of a simple proximal humeral fracture classification system among surgeons from the United States and, in particular, younger and less specialized surgeons. This finding may suggest that our interpretations of radiographic information might become more fixed and immutable with experience.

The Impact of Three-Dimensional CT Imaging on Intraobserver and Interobserver Reliability of Proximal Humeral Fracture Classifications and Treatment Recommendations

BACKGROUND

The classification systems for fractures of the proximal part of the humerus provide low interobserver and intraobserver reliability when radiographs or two-dimensional computed tomography scans are used. The purpose of this investigation was to determine whether the use of three-dimensional computed tomography scans could improve interobserver and intraobserver reliability of AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) and Neer classifications and treatment recommendations.

METHODS

Two trauma surgeons, one shoulder surgeon, two senior orthopaedic residents, and two junior orthopaedic residents reviewed the radiographs and two and three-dimensional computed tomography scans of forty fractures of the proximal part of the humerus. Each imaging modality was reviewed in isolation, and fractures were classified according to the Neer and AO/OTA classifications and treatment recommendations were provided. This process was repeated for intraobserver analysis. Interobserver agreement was calculated within and between levels of training for each classification and treatment recommendation with respect to radiographs and two and three-dimensional computed tomography scans.

RESULTS

Among attending orthopaedic surgeons and senior residents, the use of three-dimensional computed tomography did not improve agreement compared with the use of two-dimensional computed tomography for the Neer classification based on planes, the AO/OTA classification, or the treatment recommendation, but it did improve agreement among junior residents. Comparing between levels of training, three-dimensional computed tomography increased agreement only between junior residents and more experienced reviewers for the Neer classification based on planes and for the AO/OTA classification but not for the treatment recommendation. Intraobserver agreement for each reviewer for classification and treatment ranged from slight to fair and was not improved through the use of three-dimensional computed tomography.

CONCLUSIONS

In this investigation, the use of three-dimensional computed tomography imaging did not offer improved interobserver and intraobserver agreement compared with the use of two-dimensional computed tomography imaging with regard to classification and treatment of fractures of the proximal part of the humerus, except among reviewers with limited clinical experience.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A new morphological classification for greater tuberosity fractures of the proximal humerus: validation and clinical implications

In this study, we describe a morphological classification for greater tuberosity fractures of the proximal humerus. We divided these fractures into three types: avulsion, split and depression. We retrospectively reviewed all shoulder radiographs showing isolated greater tuberosity fractures in a Level I trauma centre between July 2007 and July 2012. We identified 199 cases where records and radiographs were reviewed and included 79 men and 120 women with a mean age of 58 years (23 to 96). The morphological classification was applied to the first 139 cases by three reviewers on two occasions using the Kappa statistic and compared with the AO and Neer classifications. The inter- and intra-observer reliability of the morphological classification was 0.73 to 0.77 and 0.69 to 0.86, respectively. This was superior to the Neer (0.31 to 0.35/0.54 to 0.63) and AO (0.30 to 0.32/0.59 to 0.65) classifications. The distribution of avulsion, split and depression type fractures was 39%, 41%, and 20%, respectively. This classification of greater tuberosity fractures is more reliable than the Neer or AO classifications. These distinct fracture morphologies are likely to have implications in terms of pathophysiology and surgical technique.

Fractures of the proximal humerus

Fractures of the proximal humerus have been diagnosed and managed since the earliest known surgical texts. For more than four millennia the preferred treatment was forceful traction, closed reduction, and immobilization with linen soaked in combinations of oil, honey, alum, wine, or cerate. The bandages were further supported by splints made of wood or coarse grass. Healing was expected in forty days. Different fracture patterns have been discussed and classified since Ancient Greece. Current classification of proximal humeral fractures mainly relies on the classifications proposed by Charles Neer and the AO/OTA classification. Since the late 1980's it has been known that intra- and inter-observer variation was high within the two systems. I conducted a series of observer studies to qualify the disagreement further and to study to what extent improvement of agreement could be obtained. No clinically significant differences in observer agreement were found at different levels of clinical experience, by reducing the number of categories, or by adding high quality radiographs, CT or 3D CT scans. A consistently low agreement on the Neer classification within and between untrained orthopaedic doctors was found. However, we also found that inter-observer agreement on treatment recommendation was higher than the agreement on the Neer classification. In a randomized trial we found that agreement could improve significantly by training of doctors, especially among specialists. However, classification of proximal humeral fractures remains a challenge for the conduct, reporting, and interpretation of clinical trials. The evidence for the benefits of surgery in complex fractures of the proximal humerus is weak. In three systematic reviews I studied the outcome after locking plate osteosynthesis or reverse arthroplasty in complex fractures patterns. No randomized trials or well-conducted comparative studies were identified. High failure rates suggest that the use of these implants for complex fractures of the humerus should not be used outside clinical protocols. I recommend the conduct of randomized trials, and a design of such study is proposed.

AST classification of proximal humeral fractures: introduction and interobserver reliability assessment

BACKGROUND

This article introduces an alphanumeric AST (Articular, Surgical neck, Tuberosities) classification of proximal humeral fractures, based on the number, localization, and displacement of articular and extra-articular fragments. All possible cases of proximal humeral fractures can be assessed from a single figure using this classification. The aim of the study was thus to describe the AST classification and to assess interobserver reliability.

METHODS

This classification is based on a single figure, allowing an easy description of the anatomic variants of different proximal humeral fractures. The severity of the fracture is determined by the fragment displacement in angular degrees and the major linear displacement in millimeters. AST reproducibility was assessed and compared with Neer, AO, and Duparc classifications, commonly used in clinical practice. The interobserver agreement was measured with Cohen's kappa coefficients and their 95% confidence intervals.

RESULTS

Thirteen independent observers analyzed a total of 64 X-rays. Overall kappa coefficients were 0.34, 0.29, 0.24, and 0.25 for AST, Neer, AO, and Duparc classifications, respectively.

CONCLUSION

The AST classification, which is easier to use because it is based on only one figure, is at least as reproducible as other proximal humeral fracture classifications.

Open reduction internal fixation of proximal humerus fractures

The treatment of proximal humerus fractures continues to evolve. While the many of these injuries can be managed nonoperatively, a certain percentage require operative treatment. Open reduction internal fixation can offer excellent outcomes when performed in the appropriate patient and utilizing proper techniques. This article reviews the most up-to-date literature regarding all phases of proximal humerus fracture osteosynthesis, including diagnosis, imaging, anatomic considerations, surgical indications, fixation, and surgical outcomes.

Reproducibility of three classifications of proximal humeral fractures

OBJECTIVE: To propose a new system for classifying proximal humeral neck fractures, and to evaluate intra- and interobserver agreement using the Neer system that is the most commonly used in the area and the Arbeit Gemeinschaft für Osteosynthesefragen system created by an European group, and a new classification system proposed by the authors of this study. METHODS: A total of 56 patients with proximal humeral fractures were selected, and submitted to digitized simple radiography in antero-posterior shoulder and scapular profile. Radiographs were analyzed by three observers at time one, and then three and six weeks later. The kappa coefficient modified by Fleiss was used for the analysis. RESULTS: The mean intra-observer Kappa agreement index (k=0.687) of the new classification, was higher than both the Neer classification (k=0.362) and the Arbeit Gemeinschaft für Osteosynthesefragen (k=0.46). The mean interobserver Kappa agreement index (0.446) of the new classification, also had better results than both the Neer classification (k=0.063) and the Arbeit Gemeinschaft für Osteosynthesefragen (k=0.028). CONCLUSION: the new classification considering bone compression had higher results for intra- and interobserver compared to the Neer system, and the Arbeit Gemeinschaft für Osteosynthesefragen system.

Classification and treatment of proximal humerus fractures: inter-observer reliability and agreement across imaging modalities and experience

SUMMARY

Proximal humerus fractures (PHF) are common injuries, but previous studies have documented poor inter-observer reliability in fracture classification. This disparity has been attributed to multiple variables including poor imaging studies and inadequate surgeon experience. The purpose of this study is to evaluate whether inter-observer agreement can be improved with the application of multiple imaging modalities including X-ray, CT, and 3D CT reconstructions, stratified by physician experience, for both classification and treatment of PHFs.

METHODS

Inter-observer agreement was measured for classification and treatment of PHFs. A total of sixteen fractures were imaged by plain X-ray (scapular AP and lateral), CT scan, and 3D CT reconstruction, yielding 48 randomized image sets. The observers consisted of 16 orthopaedic surgeons (4 upper extremity specialists, 4 general orthopedists, 4 senior residents, 4 junior residents), who were asked to classify each image set using the Neer system, and recommend treatment from four pre-selected choices. The results were evaluated by kappa reliability coefficients for inter-observer agreement between all imaging modalities and sub-divided by: fracture type and observer experience.

RESULTS

All kappa values ranged from "slight" to "moderate" (k = .03 to .57) agreement. For overall classification and treatment, no advanced imaging modality had significantly higher scores than X-ray. However, when sub-divided by experience, 3D reconstruction and CT scan both had significantly higher agreement on classification than X-ray, among upper extremity specialists. Agreement on treatment among upper extremity specialists was best with CT scan. No other experience sub-division had significantly different kappa scores. When sub-divided by fracture type, CT scan and 3D reconstruction had higher scores than X-ray for classification only in 4-part fractures. Agreement on treatment of 4 part fractures was best with CT scan. No other fracture type sub-division had significantly different kappa scores.

CONCLUSIONS

Although 3D reconstruction showed a slight improvement in the inter-observer agreement for fracture classification among specialized upper extremity surgeons compared to all imaging modalities, fracture types, and surgeon experience; overall all imaging modalities continue to yield low inter-observer agreement for both classification and treatment regardless of physician experience.

Classification and treatment of proximal humerus fractures: inter-observer reliability and agreement across imaging modalities and experience

SUMMARY

Proximal humerus fractures (PHF) are common injuries, but previous studies have documented poor inter-observer reliability in fracture classification. This disparity has been attributed to multiple variables including poor imaging studies and inadequate surgeon experience. The purpose of this study is to evaluate whether inter-observer agreement can be improved with the application of multiple imaging modalities including X-ray, CT, and 3D CT reconstructions, stratified by physician experience, for both classification and treatment of PHFs.

METHODS

Inter-observer agreement was measured for classification and treatment of PHFs. A total of sixteen fractures were imaged by plain X-ray (scapular AP and lateral), CT scan, and 3D CT reconstruction, yielding 48 randomized image sets. The observers consisted of 16 orthopaedic surgeons (4 upper extremity specialists, 4 general orthopedists, 4 senior residents, 4 junior residents), who were asked to classify each image set using the Neer system, and recommend treatment from four pre-selected choices. The results were evaluated by kappa reliability coefficients for inter-observer agreement between all imaging modalities and sub-divided by: fracture type and observer experience.

RESULTS

All kappa values ranged from "slight" to "moderate" (k = .03 to .57) agreement. For overall classification and treatment, no advanced imaging modality had significantly higher scores than X-ray. However, when sub-divided by experience, 3D reconstruction and CT scan both had significantly higher agreement on classification than X-ray, among upper extremity specialists. Agreement on treatment among upper extremity specialists was best with CT scan. No other experience sub-division had significantly different kappa scores. When sub-divided by fracture type, CT scan and 3D reconstruction had higher scores than X-ray for classification only in 4-part fractures. Agreement on treatment of 4 part fractures was best with CT scan. No other fracture type sub-division had significantly different kappa scores.

CONCLUSIONS

Although 3D reconstruction showed a slight improvement in the inter-observer agreement for fracture classification among specialized upper extremity surgeons compared to all imaging modalities, fracture types, and surgeon experience; overall all imaging modalities continue to yield low inter-observer agreement for both classification and treatment regardless of physician experience.

The reliability and reproducibility of the Neer classification system--digital radiography (PACS) improves agreement

INTRODUCTION

We investigated if the introduction of digital radiography, with its software permitting enhancement of plain radiographs, improved inter- and intra-observer agreement in the Neer classification.

METHODS

Five observers participated in classifying 50 randomly selected radiographs with a confirmed proximal humeral fracture. The observers included a junior registrar, an upper-limb fellow, a lower-limb orthopaedic consultant and two orthopaedic shoulder consultants. Agreement was quantified via kappa values.

RESULTS

In general, good (0.61-0.80) results were obtained using kappa value for inter-observer reliability throughout all grades. On further analysis, however, discrepancies persist in the classification between Neer type 1/2 and Neer type 5 categories. The latter was not restricted to more inexperienced surgeons. Intra-observer agreement (> 0.81) was excellent throughout all grades.

CONCLUSION

The introduction of digital radiography aids the improvement of Neer classification of proximal humeral fractures across all grades. With superior agreement in displacement and fracture patterns, improved communication and discussion of these injuries and similar treatment plans can be expected. This may help negate one aspect of the variability in outcome of proximal humeral shaft fractures. More complex fracture configurations continue to have difficulty in interpretation and may require further imaging analysis to conclude definitively.

Four-part proximal humeral fractures: diagnosis with the 'sunset' sign on anteroposterior radiograph

INTRODUCTION

Four-part proximal humeral fractures require surgical intervention. However, they can be difficult to diagnose in radiological images. We aim to define a new, easily recognisable, radiological sign as a predictor of four-part fracture of the proximal humerus in a plain anteroposterior radiograph of the shoulder.

PATIENTS AND METHODS

We describe our 'sunset' sign as 'articular surface of humeral head pointing away from the glenoid and tilted upwards, in the presence of a displaced greater tuberosity fracture'. We postulate that a patient with proximal humerus fracture showing this sign has four-part fracture until proven otherwise. Between 2002 and 2006, 80 consecutive patients had surgical treatment of their proximal humeral fractures in our unit. Pre-operative radiographs and operative notes of 79 patients were evaluated independently by three blinded observers. The presence of 'sunset' sign was recorded. Findings were then correlated with the operative diagnoses to confirm whether they were four-part fractures or not. With 95% confidence interval, we calculated the sensitivity, specificity, positive and negative predictive values for our diagnostic sign.

RESULTS

Of 79 patients, 30 displayed 'sunset' sign in their pre-operative radiograph. Of these, 28 had confirmed four-part fractures operatively. The positive predictive value of 'sunset' sign was 93%. The specificity and sensitivity were 95% and 78%, respectively. The sensitivity was affected by eight patients with four-part fractures with displaced articular head fragment which had dropped either medially or posteriorly.

CONCLUSIONS

These results suggest that, in patients with proximal humeral fractures, the presence of 'sunset' sign in the anteroposterior radiograph is a reliable indicator of four-part fracture.

The three-dimensional anatomy of proximal humeral fractures

HYPOTHESIS

Three-dimensional (3D) computed tomography (CT) reconstructions have the potential to convey the anatomy of proximal humeral fractures more realistically than do standard 2D images.

MATERIAL AND METHODS

Proximal humeral fractures in 248 adult patients were examined prospectively using 3D CT reconstructions. To our knowledge, this represents the largest reported series of such fractures examined by this method.

RESULTS

Of 248 fractures examined by a 3D classification system, 14% were of the 2 Part type, 36% were 3 Part, 21% were Shield fractures, 13% were isolated tuberosity injuries, and 16% were fracture dislocations.

CONCLUSIONS

This study led to a modification of the Neer classification system. The frequency of each type of injury in this new classification is presented and a technique for viewing 3D images is suggested which maximizes their usefulness.

LEVEL OF EVIDENCE

Level 2; Clinical, observational, and prospective.

Updated classification system for proximal humeral fractures

Proximal humeral fractures can restrict daily activities and, therefore, deserve efficient diagnoses that minimize complications and sequels. For good diagnosis and treatment, patient characteristics, variability in the forms of the fractures presented, and the technical difficulties in achieving fair results with surgical treatment should all be taken into account. Current classification systems for these fractures are based on anatomical and pathological principles, and not on systematic image reading. These fractures can appear in many different forms, with many characteristics that must be identified. However, many current classification systems lack good reliability, both inter-observer and intra-observer for different image types. A new approach to image reading, following a well-designed set and sequence of variables to check, is needed. We previously reported such an image reading system. In the present study, we report a classification system based on this image reading system. Here we define 21 fracture characteristics and apply them along with classical Codman approaches to classify fractures. We base this novel classification system for classifying proximal humeral fractures on a review of scientific literature and improvements to our image reading protocol. Patient status, fracture characteristics and surgeon circumstances have been important issues in developing this system.

Classification and imaging of proximal humerus fractures

The decision to operate and the selection of the appropriate surgical modality for proximal humerus fractures are largely based on the fracture pattern. Understanding the particular fracture pattern in each case is complicated. Most well-accepted classification systems were developed based on radiographs complemented by intraoperative findings. Three-dimensional reconstructions based on CT currently available in most institutions allow a much better understanding of complex fractures. Modern thinking about fracture classification probably should be revisited in the light of improved imaging techniques.

Open reduction and internal fixation of proximal humerus fractures

Open reduction of proximal humeral fractures has the advantage of providing direct control over each fracture fragment and permitting anatomic reduction and fixation with advanced devices. Modern fixed-angle locking plates designed specifically for proximal humerus fractures have allowed the expansion of surgical indications permitting surgeons to address more complicated fractures. Advanced preoperative imaging and fluoroscopy allow a better understanding of fracture patterns and permit the surgeon to use this knowledge intraoperatively. Research is required to further validate fracture classification systems, to develop surgical guidelines for decision making, and to compare the outcomes of the various treatments options for proximal humerus fractures.

Diagnosing displaced four-part fractures of the proximal humerus: a review of observer studies

Displaced four-part fractures comprise 2-10 % of all proximal humeral fractures. The optimal treatment is unclear and randomised trials are needed. The conduct and interpretation of such trials is facilitated by a reproducible fracture classification. We aimed at quantifying observer agreement on the classification of displaced four-part fractures according to the Neer system. Published and unpublished data from five observer studies were reviewed. Observers agreed less on displaced four-part fractures than on the overall Neer classification. Mean kappa values for interobserver agreement ranged from 0.16 to 0.48. Specialists agreed slightly more than fellows and residents. Advanced imaging modalities (CT and 3D CT) seemed to contribute more to classification of displaced four-part patterns than in less complex fracture patterns. Low observer agreement may challenge the clinical approach to displaced four-part fractures and poses a problem for the interpretation and generalisation of results from future randomised trials.

Natural history of complex fractures of the proximal humerus using a three-dimensional classification system

We studied the nonoperative treatment of proximal humeral fractures in severe injuries usually treated surgically. The natural history of 63 patients was followed prospectively for 2 to 9 years (mean, 42 months) with a nonrandomized protocol. A 3-dimensional classification system based on computed tomography scans was used to categorize the fractures. Assessment was made for range of motion, function via a validated testing instrument (Simple Shoulder Test), analog pain score, avascular necrosis (AVN), and fracture union. Magnetic resonance imaging for early signs of AVN was done in 16 cases. After conservative treatment of complex fractures of the shoulder, motion is considerably compromised but pain is minimal and functional status is acceptable to most individuals in this predominantly older patient population. Status comparable to a successful surgical shoulder fusion is achieved in most cases-Nature's fusion. Contrary to common belief, AVN, even in severely displaced injuries, is rare. Future randomized studies based on a 3-dimensional classification need to be done to compare these natural history results with various types of surgical interventions.

Inter- and intraobserver reliability of the MTM-classification for proximal humeral fractures: a prospective study

BACKGROUND

A precise modular topographic-morphological (MTM) classification for proximal humeral fractures may address current classification problems. The classification was developed to evaluate whether a very detailed classification exceeding the analysis of fractured parts may be a valuable tool.

METHODS

Three observers classified plain radiographs of 22 fractures using both a simple version (fracture displacement, number of parts) and an extensive version (individual topographic fracture type and morphology) of the MTM classification. Kappa-statistics were used to determine reliability.

RESULTS

An acceptable reliability was found for the simple version classifying fracture displacement and fractured main parts. Fair interobserver agreement was found for the extensive version with individual topographic fracture type and morphology.

CONCLUSION

Although the MTM-classification covers a wide spectrum of fracture types, our results indicate that the precise topographic and morphological description is not delivering reproducible results. Therefore, simplicity in fracture classification may be more useful than extensive approaches, which are not adequately reliable to address current classification problems.

Current concepts in the treatment of proximal humeral fractures

Preoperative classification of proximal humeral fractures in addition to thorough knowledge of the specific anatomy and vascular blood supply is more important for successful treatment than the choice of implant. If reduction and fixation is necessary, aggressive reduction maneuvers can compromise humeral head perfusion with subsequent humeral head necrosis regardless of the implant used. Modern implants such as intramedullary proximal humeral nails and anatomically designed proximal humeral angular stable plates offer high primary stability even in osteoporotic bone with preservation of periosteal blood supply to the humeral head. These implants allow early functional exercises and showed good to excellent results in the majority of patients with an acceptable complication rate. Increasing experience with these relatively new implants and further technical development might improve clinical results and reduce complications. Minimally invasive, percutaneous techniques also demonstrate favorable results comparable to those mentioned above, although mean patient age tends to be younger in these studies and complications requiring reoperation tend to be more pronounced in elderly patients due to poor bone quality. Alternatively, nonoperative treatment of displaced two- and three-part fractures in elderly patients with severe morbidity and high perioperative risks should be considered. In elderly patients with selected displaced four-part fractures or fracture dislocations and head-split fractures, hemiarthroplasty offers high subjective patient satisfaction despite moderate function with most of the patients being pain free.

Reverse shoulder arthroplasty for the treatment of proximal humeral fractures

Proximal humeral fractures occurring in elderly patients often lead to significant functional disability. The outcome of nonoperative management is disappointing. Treatment with open reduction and internal fixation may result in osteonecrosis of the humeral head, and pain. Hemiarthroplasty is often associated with tuberosity nonunion and poor function. Reverse shoulder arthroplasty is an attractive alternative because of the ability of the prosthesis to compensate for tuberosity complications. Early studies have shown promise in using the prosthesis to treat these difficult patients. The next step will require prospective, randomized studies to determine which patient groups derive any benefit from reverse shoulder arthroscopy. The technology should be used judiciously.

Reliability of Classification of Fractures of the Tibial Plafond According to a Rank-Order Method

BACKGROUND

Many orthopedic classification systems, including those for tibial plafond fractures, are either unvalidated or have demonstrated problems with interobserver reliability. Classification of tibial plafond fractures according to a rank-order method has shown excellent interobserver reliability with several observers. The purpose of this study is to determine the reliability of a rank order classification of plafond fractures with a large number of observers.

METHODS

A radiographic review study was completed by 69 orthopedists of varying training levels. Observers ranked 10 fractures of the tibial plafond based on anteroposterior and lateral ankle radiographs. Fractures were ranked in increasing severity from 1 to 10. No instructions were given regarding determination of severity. Agreement between rankings was analyzed by the intraclass correlation coefficient (ICC).

RESULTS

Rankings were performed by viewing prints at the annual Orthopaedic Trauma Association meeting and through the Orthopaedic Trauma Association website using digital images. The overall ICC was 0.62. There was no difference in the ICC between traumatologists and general orthopedists (p > 0.5). Eleven observers commented that the radiographs did not represent the full spectrum of injury severity.

CONCLUSIONS

The interobserver reliability of the rank-order classification in this study was fair to good, which is better than previously reported for plafond fracture classification systems. It remains to identify and validate a series of tibial plafond fractures that represent a full spectrum of injury and can be ranked with excellent interobserver reliability. A series of cases such as this may then serve a measurement standard for severity of bony injury against which individual cases may be reliably compared.

[Operative treatment of proximal humeral fractures with helix wire]

BACKGROUND

Between 1 January 2000 and 31 December 2002, a total of 50 patients with a dislocated or unstable fracture of the proximal humerus were treated surgically with a titanium helix wire introduced retrogradely into the medullary cavity.

MATERIAL AND METHODS

Fracture classification showed 8 cases of a two-fragment fracture, 32 cases of a three-fragment fracture, and 10 cases of a so-called four-fragment fracture. A retrospective radiographic and medical review of all 50 patients showed postoperative complications in 24% of the cases; in 8 cases (16%) secondary loss of retention occurred with consecutive projection of the helix wires into the subacromial joint space. There were two cases each (4%) of perforation of the helix wire into the joint space without loss of retention and fracture dehiscence because of a blocking mechanism by the helix wire in the subcapital fracture gap. The postoperative revision rate was 18% (9/50) as a result. Of 50 patients with a titanium helix wire, 38 (76%) were reviewed after an average of 23 months (12-31). Radiologically partial necrosis of the head of the humerus was seen in two patients and there was necrosis of the head of the humerus with pseudarthrosis in one patient, which had a negative effect on the Constant score.

RESULTS

Because of a change of procedure (n=5) and intercurrent deaths (n=5) only 2 of 12 patients, in whom complications had occurred postoperatively, could be followed up clinically; the results of the follow-up are sure to be distorted by this selection effect. Of 38 patients, 32 (84%) showed very good to good results functionally; the average Constant score was 74 points and the average age- and sex-specific corrected score was 92%.

DISCUSSION

Thus, the procedure does not achieve better functional results compared to other rigid and semirigid internal fixation methods while it has a high complication and revision rate compared to other rigid and semirigid internal fixation methods. Moreover, early functional treatment is not possible so that the titanium helix wire represents a retention aid rather than stable internal fixation. Overall we cannot recommend the procedure for the operative management of proximal humerus fractures further and have abandoned it ourselves.

Interobserver reliability of a CT-based fracture classification system

OBJECTIVES

This study was designed to determine whether the interobserver reliability of a fracture classification scheme applied based on a single, carefully defined, computed tomography (CT) cut is greater than those previously reported for systems designed for use with plain radiographs.

DESIGN

Observer review of selected cases.

SETTING

Four, level one, trauma centers.

PATIENTS

Pretreatment CT scans of patients with calcaneus fractures were screened by the authors. Thirty cases were selected that had an appropriate semicoronal CT image. Ten orthopaedic traumatologists who were members of the Orthopaedic Trauma Association and had a minimum of 5 years postresidency experience were selected as reviewers.

INTERVENTION

The reviewers were provided with a digital CT image for each case as well as written and diagrammatic representations of the Sanders classification system. The observers then classified each fracture according to the Sanders classification.

RESULTS

: The mean kappa value for interobserver reliability for fracture types I-IV was 0.41 +/- 0.02 (mean +/- standard error of the mean; range, 0.07-0.64). Observers disagreed by more than 1 fracture type (ie, I vs. III or II vs. IV) in 10% of the cases. Observers agreed on the location of the fracture lines (A, B, C) in 90% of type II fractures and 52% of type III fractures.

CONCLUSIONS

The results indicate that in a carefully controlled paradigm, the interobserver reliability with a classification system based on interpretation of a single, carefully defined CT image was no better than the results reported for the same classification system used with full CT data or for other classification systems used for various fractures in the skeleton. Agreement in identifying the location of the fracture lines was very good for simple fractures but much worse for complex injuries. Additional study may determine whether the use of a full complement of CT images can improve reliability in classification of complex injuries.

Characteristics of an isolated greater tuberosity fracture of the humerus

BACKGROUND

Most classification systems tend to include isolated greater tuberosity fractures in the group of proximal humeral fractures. The purpose of this study was to elucidate demographic differences between isolated greater tuberosity fractures and the other proximal humeral fractures.

METHODS

Altogether, 610 proximal humeral fractures were divided into isolated greater tuberosity fractures of the proximal humerus (group I) and all other proximal humeral fractures (group II). The two groups were analyzed according to their incidence, age and sex distribution, presence of dislocation, and associated chronic medical problems.

RESULTS

Group I comprised 18.9% and group II 81.1% off all fractures. The mean age of group I was 42.8 years, and that of group II was 54.2 years. Of the 115 (67.8%) patients in group I, 78 (67.8%) were male. In contrast, most of the group II patients were female (332/495, 67.1%). A higher incidence of glenohumeral dislocation occurred in group I (6.9%) than in group II (3.4%). Of the 495 group II patients, 175 (35.4%) had medical problems, including endocrine, cardiovascular, pulmonary, hepatic, and renal disease, whereas only 15 of the 115 (13%) patients in group I had such problems.

CONCLUSIONS

Patients with isolated greater tuberosity fractures of the proximal humerus were different demographically, and their treatment and classification should be considered separately from that for other proximal humeral fractures.

A concept for the validation of fracture classifications

The fracture classification systems currently used most frequently were not developed or validated by rigorous scientific evaluation methods. This paper discusses the classification of fractures from an epidemiological and clinical decision-making perspective and proposes a standardized methodological concept for their development and scientific validation. Classification categories are clinically relevant entities that surgeons should be able to use for diagnosis with sufficient confidence to limit misclassification and associated treatment errors. The process of validation should assess the value of specific clinical information (eg, the use of radiographs or computed tomography scans) in increasing the probability of a correct diagnosis. A 3-phase validation concept is proposed where: 1) classification categories are defined and the classification process using specific diagnostic images is evaluated by experts in a series of agreement studies (reliability, accuracy, likelihood ratios); 2) a multicenter agreement study is conducted among a representative group of future users of the classification; and 3) the classification proposal is applied in the context of a prospective clinical study to assess its clinical usefulness.

Multidetector CT in shoulder fractures

The aim of this study was to assess the multi-detector computed tomography (MDCT) findings in acute shoulder traumas compared to radiographic findings in patients referred to a level one trauma center. Two hundred and ten patients (128 male, 82 female, age 16-95 years, mean age 51.7 years) underwent shoulder MDCT due to acute trauma. Three main mechanisms of injury were established: falling (113 patients, 54%), traffic accidents (36 patients, 17%) and falling from a height (12 patients, 6%). Based on MDCT, a total of 311 fractures--152 in the scapula and 159 in the proximal humerus--occurred in 191 (91%) of the 210 patients. The two most common occult fractures were lesser tubercle and coracoid process fractures. In 20 (63%) of the patients with a comminuted fracture of proximal humerus the exact number of fracture fragments was underestimated in radiographs. MDCT with multiplanar reconstructions (MPR) is a recommended complementary examination in patients with complex proximal humerus fractures where the extent of the fractures and the position or origin of dislocated fragments is not clear on radiography. This may increase the accuracy of the fracture classification and reveal occult fractures in other parts of the shoulder.

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

Two independent reviewers performed a search in MEDLINE and EMBASE for fracture classification reliability studies. Data were obtained on classifications, image modalities, fracture selection processes, sample sizes and their justification, type and number of raters, practical issues for the classification sessions, statistical methods, and results. A 10-item checklist was devised for quality assessment of methodologies. 44 studies assessing 32 fracture classification systems were included. We found a wide variation of methodologies. For instance, the median number of raters was 5 (2-36) and the median number of fractures was 50 (10-200). This selection was considered representative in 17/44 of the studies. The true distribution of classification categories was estimated in 9 studies. The kappa coefficient was mostly used (39/44) to quantify the raters' agreement. Methodological issues are discussed. Given limitations in the use and interpretation of kappa coefficients, investigators should consider alternative methods that focus upon the accuracy of the classification systems. The development and adoption of a systematic methodological approach to the development and validation of fracture classification systems is needed.

Accuracy of the axillary projection to determine fracture angulation of the proximal humerus

The accuracy of measuring angulation of stable proximal humerus fractures using the axillary lateral projection was investigated. A closing wedge osteotomy with apex anterior angulation was performed on two cadaveric humeri to simulate a stable surgical neck fracture. One specimen was fixed at 30 degrees angulation and the other at 55 degrees. Axillary radiographs were taken with each specimen articulating with the glenoid of a cadaveric scapula. The humerus was held in neutral rotation. Abduction was set at 30 degrees, 60 degrees, and 90 degrees. In each position of abduction, an axillary lateral radiograph was taken in 30 degrees forward flexion, neutral, and 30 degrees extension to simulate various arm positions. A total of nine radiographs were taken for each specimen. The axillary view is not accurate for measurement of proximal humerus angulation at the arm positions commonly encountered in the trauma setting.

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.

The epidemiology of proximal humeral fractures

We present a 5-year prospective study of the epidemiology of 1,027 proximal humeral fractures. These fractures, which tend to occur in fit elderly persons, have a unipolar age distribution and the highest age-specific incidence occurs in women between 80 and 89 years of age. The commonest was the B1.1 impacted valgus fracture, found in one-fifth of the cases in this series, a type that is not included in the Neer classification. We used both Neer and AO classifications. The AO classification proved to be more comprehensive because in the Neer classification, half of the fractures are minimally displaced and almost nine-tenths fall into only three categories. In the AO classification, the B1.1, A2.2, A3.2 and A1.2 sub-groups comprise over half of all proximal humeral fractures, while the AO type C fractures occur in only 6%. We suggest that the literature does not adequately reflect the spectrum of proximal humeral fractures.

Reliability of Hand Fellows’ Measurements and Classifications from Radiographs of Distal Radius Fractures

The inter-rater reliability of classification systems and the direct measurement of fracture displacement was evaluated for two hand fellows in 128 radiographs of distal radius fractures. The fracture classifications rated were the Older, Mayo, AO, McMurtry, Universal and Frykman systems. Measurements of displacement were radial tilt, radial shortening and dorsal angulation on pre- and postreduction films. Intraclass correlation coefficients (ICCs) and kappas, and their associated 95% confidence intervals were calculated. Inter-rater reliability for classification systems was poor, with the exception of the Older system (kappa = 0.73). Prereduction measurement of radial inclination, dorsal angulation and radial shortening had excellent reliability (ICC 0.77). Postreduction films exhibited lower reliability in the same measurements (ICC 0.76). Hand fellows reported inconsistent use of classification systems or radiographical measurements in clinical practice. Further training and/or an increased emphasis on direct measurements, rather than classifications, may be warranted.

Effect of screw placement on fixation in the humeral head

The objectives of this study were (1) to determine the most advantageous screw locations within the humeral head when plate and screw fixation is to be used and (2) to determine the effect of positioning the screw tip abutting the subchondral bone. Ten paired humeral heads were harvested with a monoplanar cut through the anatomic neck. Through use of a standardized template, 7 holes were drilled and tapped in each specimen for insertion of 6.5-mm fully threaded cancellous screws perpendicular to the plane of the cut. Paired specimens were randomized into 2 groups, one with the screw purchase in central cancellous bone and the other with the screw purchase up to the subchondral bone. Each screw was pulled out axially at a displacement rate of 10 mm/min through use of a servohydraulic testing machine. The length of thread purchase, position within the head, and screw pullout load to failure were recorded. The normalized pullout force to failure was calculated by dividing absolute pullout force to failure by length of screw purchase. Data were analyzed by means of a 2-way repeated measures analysis of variance and post hoc Student-Newman-Keuls test. The central position had a significantly higher absolute pullout force to failure than all other sites (P < .05). By virtue of the humeral head shape, the central position also had a significantly greater length of screw purchase than all other positions (P < .05). The central position had a significantly higher relative pullout force to failure than all other positions (P < .05). Subchondral bone abutment positioning improved both the absolute and the relative pullout forces to failure (P < .05). When screws and plates are used in open reduction and internal fixation of a proximal humerus fracture, a major mode of failure is loss of fixation within the humeral head. On the basis of this study, optimal screw purchase with respect to bone fixation can be achieved by including screws located in the center of the humeral head in the subchondral abutment position. To minimize screw fixation failure, the anterosuperior position should be avoided. The pattern of distribution of the relative pullout force as measured in this study is consistent with previous observational studies of patterns of trabecular density within the humeral head.

Radiographic fracture assessments: which ones can we reliably make?

OBJECTIVE

To identify the fracture characteristics that can be reliably assessed by analysis of plain radiographs of tibial plateau fractures.

DESIGN

Radiographic review study.

PARTICIPANTS

Five orthopaedic traumatologists served as observers.

INTERVENTION

Observers made assessments based on the radiographs of fifty-six tibial plateau fractures. Precise definitions of the assessments to be made were agreed on by all observers. The tested assessments included raters' abilities to identify and locate fracture lines, identify the presence of fracture displacement and comminution, make quantitative measurements of displacement, and characterize qualitative features of fractures. For thirty-eight of the fractures that had a computed tomography (CT) scan available, assessments were repeated using both radiographs and CT scans.

MAIN OUTCOME MEASURES

To characterize interobserver reliability, percentage agreement and kappa statistics were calculated for categorical variables, and intraclass correlation coefficients (ICC) were calculated for noncategorical variables.

RESULTS

Reliability of the assessments varied widely. Determining the location of fracture lines had the greatest reliability, whereas the subjective assessments of fracture stability and energy showed the poorest reliability. Although the ICCs for quantitative measurements approached acceptable levels, the tolerance limits were extremely wide. The addition of a CT scan improved the reliability of most assessments, but not to a statistically significant degree.

CONCLUSIONS

Many basic radiographic interpretations relied on in making treatment decisions are made variably by observers. Using experienced raters and precise definitions of fracture assessments does not guarantee a high level of agreement. Discrete assessments have higher interrater agreements than do more qualitative assessments. Quantitative measures have wide tolerance limits and, therefore, probably cannot be used reproducibly to classify fractures or make treatment decisions. We conclude the reliability of fracture classification is limited by raters' abilities to agree on basic radiographic assessments.

3D-radiographic analysis does not improve the Neer and AO classifications of proximal humeral fractures

The Neer and AO fracture classifications for fractures of the proximal humerus have shown poor reproducibility based on plain radiography. We wanted to investigate whether the addition of 3-dimensional (3D) reconstructions would increase the reproducibility of classification. 7 observers independently classified 24 fractures of the proximal humerus using both plain radiographs, CT and 3D and the classification was repeated 2 months later. There was a moderate interobserver agreement when using the Neer classification, but only a fair agreement with the AO classification. The Neer system had a mean kappa value of 0.44 and the AO had a value of 0.32 for the first assessment. In the second assessment, the mean kappa values were 0.49 and 0.34, respectively. Intraobserver reproducibility was fair to substantial agreement for Neer (kappa range 0.27-0.73) and for AO (kappa range 0.29-0.74). In conclusion, the addition of CT and 3D to plain radiographs did not improve the reproducibility of the classifications of Neer and AO of the proximal humerus.

Effects of binary decision making on the classification of fractures of the ankle

OBJECTIVE

To evaluate the effect of binary decision making on interobserver reliability in the classification of fractures of the ankle.

DESIGN

Radiographic review study.

PATIENTS/PARTICIPANTS

Observers: two PGY-2 orthopaedic residents, two PGY-5 residents, and two orthopaedic attending surgeons.

INTERVENTION

Radiographs of fifty ankle fractures were classified. Each observer classified the radiographs by using the original AO/ASIF system and its recent binary modification.

MAIN OUTCOME MEASUREMENTS

Interobserver reliability was assessed by using a kappa coefficient and compared for the two classification methods.

RESULTS

The mean kappa value for interobserver reliability for type only and for type and group classification when using the original AO/ASIF system was 0.77 and 0.61, respectively. Using binary decision making, the mean kappa values for type only and for type and group were 0.78 and 0.62, respectively. There was no statistically significant difference in reliability between the original and binary classification systems.

CONCLUSION

The interobserver reliability of both the original AO/ASIF classification system and its binary modification is substantial. The results of the present study, however, cast doubt on the effectiveness of binary decision making in improving interobserver reliability in the classification of fractures. To our knowledge, this study is the first to compare the original AO/ASIF classification system with its binary modification. Additional study of other fractures may help elucidate the effectiveness of binary decision making in improving interobserver reliability in the classification of all fractures.

A critical assessment of factors influencing reliability in the classification of fractures, using fractures of the tibial plafond as a model

OBJECTIVE

To investigate three factors that may influence the reliability of a fracture classification system: (a) the quality of the radiographs; (b) the ability of observers to identify the fracture fragments; and (c) the use of binary decision making.

DESIGN

Assessment of interobserver reliability of blinded observers.

SETTING

Medical school department of orthopaedics.

PARTICIPANTS

Two attending orthopaedists, two PGY-5 orthopaedic residents, and two PGY-3 orthopaedic residents served as observers.

INTERVENTION

Observers classified radiographs of twenty-five tibial plafond fractures according to the Rüedi-Allgöwer and binary classification systems, and also rated the quality of each radiograph as adequate or inadequate for accurately classifying the fracture. At a second session, observers classified the same radiographs after marking the fragments of the tibial articular surface, as well as radiographs that had the articular fragments premarked by the senior author.

MAIN OUTCOME MEASURES

Pairwise interobserver reliability was analyzed by kappa statistics, and mean kappa values were compared for each method of fracture classification.

RESULTS

No difference in interobserver reliability was detected between the Rüedi-Allgöwer and binary classification systems. Interobserver agreement on the adequacy of the radiographs was poorer than agreement on the classification of the fractures themselves. Having observers mark the fragments of the tibial articular surface had no effect on interobserver reliability; having the articular fragments premarked, however, significantly improved interobserver reliability in classifying the fractures.

CONCLUSIONS

The results of this study underscore the complexity of tibial plafond fractures and the difficulty observers have in reliably interpreting fracture radiographs. Fracture classification systems, such as the Rüedi-Allgöwer, predicated on identification of the number and displacement of articular fragments, may inherently perform poorly on reliability analyses because of observer difficulty in reliably identifying the fragments. Because binary decision making did not improve the reliability of fracture classification in this study, further investigation of the effectiveness of binary decision making may be advisable before such strategies are put into widespread use.

Poor reproducibility of classification of proximal humeral fractures. Additional CT of minor value

Fractures of the proximal humerus can be described using the Neer and AO fracture classifications. To assess the reproducibility and reliability of these classifications, we investigated 26 proximal humeral fractures with both plain radiographs and CT. 5 specialists in orthopedic surgery and 5 specialists in radiology independently classified all radiographs on 2 occasions. There was a moderate agreement between the observers when using the Neer classification, but only a fair agreement with the AO classification. The Neer system had a kappa value of 0.42 and the AO had a value of 0.31 in the first assessment. In the second assessment the kappa values were 0.45 and 0.30, respectively. Intraobserver reproducibility was slight to almost perfect agreement with Neer (kappa range 0.20-0.85) and slight to moderate agreement with AO (kappa range 0.16-0.60). The observers most familiar with shoulder fracture radiographs and shoulder fracture treatment were more consistent in their classifications. We conclude that even with CT, the fracture classifications of Neer and AO have a low consistency. Neither classification system is reproducible enough to allow comparisons of different studies.