Indications for computed tomography (CT-) diagnostics in proximal humeral fractures: a comparative study of plain radiography and computed tomography

Fracture line and comminution zone characteristics, and rotator cuff footprint involvement in OTA/AO 11C3-type proximal humeral fractures: complex proximal humerus fracture map

PURPOSE

To identify fracture characteristics and zones of comminution as well as the relationship with anatomic landmarks and rotator cuff footprint involvement in OTA/AO 11C3-type proximal humerus fractures.

METHODS

Computed tomography images of 201 OTA/AO 11C3 fractures were included. Fracture lines were superimposed to a 3D proximal humerus template, created from a healthy right humerus, after fracture fragment reduction on 3D reconstruction images. Rotator cuff tendon footprints were marked on the template. Lateral, anterior, posterior, medial, and superior views were captured for the interpretation of fracture line and comminution zone distribution as well as to define the relationship with anatomic landmarks and rotator cuff tendon footprints.

RESULTS

A total of 106 females and 95 males (mean age = 57.5 ± 17.7 [range 18-101] years) with 103 C3.1-, 45 C3.2-, and 53 C3.3-type fractures were included. On the lateral, medial, and superior humeral surfaces, fracture lines and comminution zones were distributed differently in 3 groups. Tuberculum minus and medial calcar region were significantly less severely affected in C3.1 and C3.2 fractures than C3.3 fractures. The supraspinatus footprint was the most severely affected rotator cuff footprint area.

CONCLUSIONS

Specifically defining the certain differences for repeatable fracture patterns and comminution zones in OTA/AO 11C3-type fractures and the relationship between the rotator cuff footprint and the joint capsule may contribute to the decision-making process of surgeons.

Fracture Dislocations of the Glenohumeral Joint

PURPOSE OF REVIEW

Proximal humerus fracture dislocations typically result from high-energy mechanisms and carry specific risks, technical challenges, and management considerations. It is vital for treating surgeons to understand the various indications, procedures, and complications involved with their treatment.

RECENT FINDINGS

While these injuries are relatively rare in comparison with other categories of proximal humerus fractures, fracture dislocations of the proximal humerus require treating surgeons to consider patient age, activity level, injury pattern, and occasionally intra-operative findings to select the ideal treatment strategy for each injury. Proximal humerus fracture dislocations are complex injuries that require special considerations. This review summarizes recent literature regarding the evaluation and management of these injuries as well as the indications and surgical techniques for each treatment strategy. Thorough pre-operative patient evaluation and shared decision-making should be employed in all cases. While nonoperative management is uncommonly considered, open reduction and internal fixation (ORIF), hemiarthroplasty, and reverse total shoulder replacement are at the surgeon's disposal, each with their own indications and complication profile.

Intraoperative 3D imaging in plate osteosynthesis of proximal humerus fractures

INTRODUCTION

Proximal humerus fractures are common and often associated with osteoporosis in the elderly. Unfortunately, the complication and revision rate for joint-preserving surgical treatment using locking plate osteosynthesis is still high. Problems include insufficient fracture reduction and implant misplacement. Using conventional intraoperative two dimensional (2D) X-ray imaging control in only two planes, a completely error-free assessment is not possible.

MATERIALS AND METHODS

The feasibility of intraoperative three-dimensional (3D) imaging control for locking plate osteosynthesis with screw tip cement augmentation of proximal humerus fractures was retrospectively studied in 14 cases with an isocentric mobile C-arm image intensifier set up parasagittal to the patients.

RESULTS

The intraoperative digital volume tomography (DVT) scans were feasible in all cases and showed excellent image quality. One patient showed inadequate fracture reduction in the imaging control, which then could be corrected. In another patient, a protruding head screw was detected, which could be replaced before augmentation. Cement distribution in the humeral head was consistent around the screw tips with no leakage into the joint.

CONCLUSION

This study shows that insufficient fracture reduction and implant misplacement can be easily and reliably detected by intraoperative DVT scan with an isocentric mobile C-arm set up in the usual parasagittal position to the patient.

Computed Tomography Does Not Improve Intra- and Interobserver Agreement of Hertel Radiographic Prognostic Criteria

Background and Objectives: Proximal humerus fractures are the second most frequent site of avascular necrosis (AVN), occurring in up to 16% of cases. The Hertel criteria have been used as a reference for the prediction of humerus head ischemia. However, these are based solely on the use of radiographs, which can make interpretation extremely difficult due to several reasons, such as the overlapping fragments, severity of the injury, and noncompliant acute pain patients. The objectives of the study were to evaluate the role of computed tomography (CT) in the interpretation of the Hertel criteria and to evaluate the intra- and interobserver agreement of orthopedic surgeons, comparing their area of expertise. Materials and Methods: The radiographs and CT scans of 20 skeletally mature patients who had fractures of the proximal humerus were converted to jpeg and mov, respectively. All images were evaluated by eight orthopedic surgeons (four trauma surgeons and four shoulder surgeons) in two different occasions. The intra- and interobserver agreement was assessed by using the Kappa coefficient. The level of significance was 5%. Results: There was a weak-to-moderate intraobserver agreement (κ < 0.59) for all examiners. Only the medial metaphyseal hinge greater than 2 mm was identified by 87.5% of evaluators both in the radiographic and CT examinations in the two rounds of the study (p < 0.05). There was no significant interobserver agreement (κ < 0.19), as it occurred only in some moments of the second round of evaluation. Conclusions: The prognostic criteria for humeral head ischemia evaluated in this study showed weak intra- and interobserver agreement in both the radiographic and tomographic evaluation. CT did not help surgeons in the primary interpretation of Hertel prognostic criteria used in this study when compared to the radiographic examination.

Imaging of traumatic shoulder injuries – Understanding the surgeon’s perspective

Imaging plays a key role in the assessment and management of traumatic shoulder injuries, and it is important to understand how the imaging details help guide orthopedic surgeons in determining the role for surgical treatment. Imaging is also crucial in preoperative planning, the longitudinal assessment after surgery and the identification of complications after treatment. This review discusses the mechanisms of injury, key imaging findings, therapeutic options and associated complications for the most common shoulder injuries, tailored to the orthopedic surgeon’s perspective.

Proximal Humerus Fractures in the Pediatric Population

PURPOSE OF REVIEW

The purpose of this review is to review recent literature focusing on proximal humerus anatomy, epidemiology of these fractures, diagnosis and treatment options, and clinical outcomes.

RECENT FINDINGS

Non- or minimally displaced proximal humerus fractures treated nonoperatively do not lead to short- or long-term complication and do not cross over to operative treatment. There is a higher rate of operative management with older age, increased injury severity score, treatment at an adult hospital, and private insurance. Operative management is preferred with closed or open reduction and percutaneous pinning, but elastic nailing and plate fixation are other options with good postoperative outcomes. Pediatric proximal humerus fractures occur after fall onto the affected shoulder or arm. Diagnosis is usually made with radiographs. Understanding the proximal humerus anatomy is critical to the proper management of these injuries to aid reduction and predict remodeling potential. There is considerable debate around the management of proximal humerus fractures in the pediatric population. Treatment is based on patient age, fracture displacement, and remodeling capacity. Nonoperative management is successful in younger patients or less displaced fractures, and operative management is usually considered in older patients with more displaced fractures.

Epiphyseal fragment as a predictive factor of failure in fixation of proximal fractures of the humerus

INTRODUCTION

Fractures of the proximal humerus are frequent and are widely studied with regards to their treatment indications. The aim of this article is to establish a correlation between the size of the epiphyseal fragment in fractures of the proximal humerus and the probability of loss of reduction after a surgical procedure.

METHODS

A total of 47 surgically treated proximal humeral fractures were reviewed. Preoperative CT scans were used to evaluate the size of the epiphyseal fragment of the fracture. Postoperative X-rays were analyzed to assess complications, especially loss of reductions. Mean age was 61 years old (29-91 years).

RESULTS

In total, 42 shoulders were evaluated. The average size of the epiphyseal fragment was 38.3 mm (32-50 mm) the largest longitudinal length; and 19.9 mm (12-30 mm) the largest cross-sectional length. The most frequent complication observed was loss of reduction. The statistical analysis showed significance that patients with smaller cross-sectional size of the epiphyseal fragment presented more complications (p = 0.034), and based on the graph and ROC curve, a value of 15.5 mm was considered as the cutoff value for failure.

CONCLUSION

A cross-sectional length of the epiphyseal fragment of less than 15.5 mm indicates a higher probability of loss of reduction in fractures of the proximal end of the humerus after extra-medullary osteosynthesis.

Preoperative measurement of the thickness of the center of the humeral head predicts screw cutout after locked plating of proximal humeral fractures

HYPOTHESIS AND BACKGROUND

Preoperative computed tomography (CT) scans can be used to measure the thickness of the center of the humeral head to identify patients at a higher risk of screw cutout after open reduction-internal fixation.

METHODS

At an academic medical center, we performed a retrospective review of all patients aged ≥ 18 years who had sustained a proximal humeral fracture that was treated with open reduction-internal fixation between January 1, 2005, and December 31, 2014, and who underwent preoperative shoulder CT. Ninety-four patients were included. Patient charts were reviewed to obtain demographic data, and radiographs were reviewed to assess screw cutout. A standardized method was devised to measure the thickness of the center of the humeral head.

RESULTS

Screw cutout developed in 17 patients (17.7%). The mean humeral head thickness was significantly smaller on the axial (18 mm vs. 21 mm, P = .0031), coronal (18 mm vs. 21 mm, P = .0084), and sagittal (18 mm vs. 21 mm, P = .0033) sections in the patients who experienced screw cutout. When the smallest of the 3 measurements for each patient was analyzed, the risk of cutout was markedly greater when the humeral head thickness was <20 mm (25% vs. 6%). In addition, when the humeral head thickness was >25 mm, the risk of cutout was reduced to 0%. A low-energy injury was associated with a lower risk of cutout whereas age, sex, and fracture classification were not independent predictors of cutout on multivariate logistic regression.

CONCLUSIONS

In a patient with a proximal humeral fracture in whom a preoperative CT scan is available, calculating the thickness of the center of the humeral head may provide valuable information to both the surgeon and the patient for preoperative planning and counseling. A smaller thickness of the center of the humeral head on preoperative CT is predictive of screw cutout following locked plating of proximal humeral fractures. A measurement of >25 mm in any one plane is highly protective against cutout; however, extreme caution and consideration of supplemental fixation methods should be taken when the measurements in all planes are <15 mm. This information may be helpful in counseling patients regarding the possibility of postoperative screw cutout.

High-Energy Proximal Humerus Fractures in Geriatric Patients: A Review

High-energy proximal humerus fractures in elderly patients can occur through a variety of mechanisms, with falls and MVCs being common mechanisms of injury in this age group. Even classically low-energy mechanisms can result in elevated ISS scores, which are associated with higher mortality in both falls and MVCs. These injuries result in proximal humerus fractures which are commonly communicated via Neer’s classification scheme. There are many treatment options in the armamentarium of the treating surgeon. Nonoperative management is widely supported by systematic review as compared to almost all other treatment methods. ORIF is particularly useful for complex patterns and fracture dislocations in healthy patients. Hemiarthroplasty can be of utility in patients with fracture patterns with high risk of AVN and poor bone quality risking screw cut-out. Reverse total shoulder arthroplasty is a popular method of treatment for geriatric patients also, with literature now showing that even late conversion from nonoperative management or ORIF to rTSA can lead to good clinical outcomes. Prevention is possible and important for geriatric patients. Optimizing medical care including hearing, vision, strength, and bone quality, in coordination with primary care and geriatricians, is of great importance in preventing fractures and decreasing injury when falls do occur. Involving geriatricians on dedicated trauma teams will also likely be of benefit.

Proximal Humerus Fractures in the Elderly: Concomitant Fractures and Management

INTRODUCTION

The purpose of this study was to identify additional injuries commonly seen with proximal humerus fractures experienced by patients 65 years or older and to evaluate discrepancies in the management of these patients with regard to provider type.

METHODS

A retrospective review was conducted of all patients 65 years or older who sustained a proximal humerus fracture. Patient data collected included demographics, injury details, hospital course, and discharge destination.

RESULTS

Patients with a concomitant fracture (45.5%, n = 65) had a slightly higher Injury Severity Score (ISS; 8.3 ± 3.0 vs. 6.4 ± 3.0, p < 0.001) and experienced one additional death than those with an isolated fracture (54.5%, n = 78). Slightly more patients were managed by a trauma provider (51.7%, n = 74) than by a non-trauma provider (48.3%, n = 69). Those managed by a trauma provider sustained the most pelvic fractures (12.2% vs. 2.9%, p = 0.038), were more likely to be injured in a motor vehicle collision (8.1% vs. 0%, p = 0.005), had a higher ISS (8.0 ± 3.3 vs. 6.4 ± 2.8, p = 0.003), and had more imaging performed than those treated by a non-trauma provider. There was, however, no difference in operative rates, concomitant injuries, length of stay, or discharge disposition regarding provider type.

CONCLUSION

It is important to recognize proximal humerus fractures as a sign of fragility and to optimize hospital management of these patients.

Bursal lipohematoma: a CT sign of full thickness rotator cuff tear in patients with proximal humerus fractures

PURPOSE

The main purpose of the study is to determine if the presence of a particular computed tomography (CT) imaging finding, a bursal lipohematoma, portends the presence of a concomitant rotator cuff tear (RCT) in patients with proximal humerus fractures by reviewing previous CTs.

METHODS

Three hundred eighty-six CT scans were retrospectively reviewed by two board-certified radiologists to determine the presence of a proximal humerus fracture and to assess for the presence of a subacromial/subdeltoid or subcoracoid bursal hematoma. The medical record including operative documentation was then examined in the patients with proximal humerus fractures, with or without a concomitant bursal lipohematoma.

RESULTS

Of the surgically managed patients, four had an intraoperative diagnosis of RCT. The preoperative CT scans of all of these patients demonstrated a bursal lipohematoma. Additionally, a non-surgically managed patient with a subacromial/subdeltoid bursal lipohematoma on CT scan was found to have a RCT on subsequent MRI. Of note, a rotator cuff tear was not documented in operative reports of patients with CT scans that were not found to contain a bursal lipohematoma.

CONCLUSIONS

Bursal lipohematoma is a potentially useful preoperative CT sign of full thickness rotator cuff tear in patients with proximal humerus fractures, providing the clinician with more information in the optimization of the management approach.

Coronal displacement in proximal humeral fractures: correlation between shoulder radiographic and computed tomography scan measurements

BACKGROUND

The purpose of this study was to analyze if there is a correlation in displacement measurements in coronal projections between shoulder radiographs and computed tomography (CT) scans in patients with proximal humeral fractures (PHFs).

METHODS

A comparative, retrospective analysis of images from our database was performed. Ninety-seven cases with PHFs with radiographs and CT scans were included. Four evaluators measured PHF displacement using the following: metaphyseal extension (ME), medial calcar (MC) medialization, apex-tuberosity distance (ATD), and cervicodiaphyseal (CD) angle. Measurement reliability was evaluated with a pilot sample by performing intraclass coefficient correlation analysis. Surgery indication according to displacement (CD angle <105° or >155° and ATD <3 mm) and agreement analysis were assessed by κ tests.

RESULTS

All evaluated parameters presented correlations among methods for intrarater and inter-rater reliability. All measurements showed significant differences (ME of 1.2 ± 6 mm, P = .034; MC of 1 ± 5 mm, P = .041; ATD of 2.6 ± 5 mm, P = .001; and CD angle of 9° ± 16°, P = .001). Regarding indications for treatment type relating to ATD and CD angle, there was agreement between CT scans and radiographs in 66 of 97 cases (κ = 0.351, P < .001). Twelve cases with surgical indications by CT scans had conservative indications by radiographs, whereas in 19 cases with conservative indications by CT scans, radiographic measurements suggested surgical treatment.

CONCLUSION

This study documented regular concordance between radiographs and CT scans for coronal displacement measurements in PHFs. Statistical differences were documented for all measurements. Webelieve that ATD and CD angle differences are clinically relevant (mean, 3 mm and 9°, respectively) because these differences might change the type of treatment.

Surgical Treatment of Displaced Greater Tuberosity Fractures of the Humerus

Greater tuberosity fractures of the humerus can be successfully treated nonsurgically in most patients. However, as little as 3 to 5 mm of superior greater tuberosity displacement may adversely affect rotator cuff biomechanics and lead to subacromial impingement in patients who are active. In these cases, surgical treatment is recommended. Multiple surgical techniques include open and arthroscopic options tailored to fracture morphology, and strategies for repair include the use of suture anchors, transosseous sutures, tension bands, and plates/screws. Three classification systems are commonly used to describe greater tuberosity fractures: the AO, Neer, and morphologic classifications. Several hypotheses have been discussed for the mechanism of greater tuberosity fractures and the deforming forces of the rotator cuff, and the use of advanced imaging is being explored.

The Axillary View Typically Does Not Contribute to Decision Making in Care for Proximal Humeral Fractures

BACKGROUND

Convention dictates that an axillary view be obtained when evaluating proximal humerus fractures (PHF). However, the axillary view is frequently omitted because of pain and technical considerations. Furthermore, its diagnostic utility is unclear in this setting.

QUESTIONS/PURPOSES

The purpose of this study was to (1) determine the rate of obtaining an adequate axillary X-ray and complete shoulder series at a level I trauma center, (2) understand the cost of ordering and attempting an axillary radiograph, and (3) determine if axillary radiographs influence the management of PHF.

PATIENTS AND METHODS

PHF treated between 2009 and 2011 that were ordered for an AP, scapular Y, and axillary view was identified. The types of radiographs actually obtained were recorded. The cost of obtaining three views and a single view of the shoulder with X-ray was determined. Lastly, three surgeons reviewed 42 PHF, both with and without an axillary view (AV), and treatment recommendations were compared.

RESULTS

30% of PHF in this series had an adequate axillary view, and 14% received a complete trauma series. No factors could be identified that were associated with successfully obtaining an axillary view. Reviewers demonstrated substantial intraobserver reliability (κ = 0.759-0.808) regarding treatment recommendations for PHF with and without the axillary view. The addition of the AV had minimal influence on treatment recommendations.

CONCLUSION

Considering that the axillary view for PHF is painful, labor-intensive, costly, and does not appear to provide additional diagnostic value, orthopedic surgeons can consider foregoing the use of the axillary view when evaluating and treating PHF, particularly if other advanced imaging is utilized.

A review of current concepts in the management of proximal humerus fractures

Fracture of the proximal humerus is a common orthopaedic injury and is likely to increase in incidence. This fracture type is associated with a wide variety in fracture morphology and as a direct result there are many treatment options available. It is often not clear what treatment modality should be utilised. This article reviews the current literature on proximal humerus fractures offering evidence for care pathways and management strategies from presentation to rehabilitation.

[Multiplanar reconstruction with mobile 3D image intensifier. Surgical treatment of proximal humerus fractures]

PURPOSE

The aim of this study was to analyze the applicability and advantages of the intraoperative use of a mobile 3D C-arm with multiplanar imaging for surgery of acute proximal humerus fractures.

MATERIALS AND METHODS

In this study 20 patients (11 female, 9 male, median age 70 years, range 35-91 years) with dislocated proximal humerus fractures (6 with 2 segments, 10 with 3 segments and 4 with 4 segments) were included. Preoperatively 3D scanning was performed and a reevaluation of the fracture in comparison to the plain radiographs was performed. After operative treatment another scan was performed to evaluate technical complications.

RESULTS

In comparison to the multiplanar reconstructions fracture morphology could not be correctly detected in 5 out of the 20 cases with plain radiographs. The preoperative image quality of the multiplanar reconstructions showed a significantly better assessment in comparison to the image quality with osteosynthesis (p < 0.05). The screws had to be replaced in 5 of the 20 patients.

CONCLUSION

Intraoperative 3D imaging with mobile image intensifier enables an accurate analysis of fracture morphology. Furthermore a quasi real time preoperative planning, evaluation of reduction and implant position with immediate operative relevance can be realized.

[Treatment of proximal humeral fractures in Germany: Influence of the level of hospital care and the frequency of treatment]

BACKGROUND

Various treatment options exist for displaced proximal humeral fractures. The impact of the level of hospital care and frequency of treatment on current treatment regimens in Germany was analyzed.

MATERIAL AND METHODS

A total of 576 hospitals were included. The survey covered questions on frequency, diagnostics, classification, therapy, complications, and clinical scenarios.

RESULTS

In all, 48% of the hospitals returned the questionnaire: 73% treat more than 60% of the fractures surgically, mainly with angle-stable implants. The angle-stable plate is the treatment of choice for young patients, but older patients are treated using other treatment options. Problems and complications included malreduction, secondary displacement, screw perforation, avascular necrosis, and impingement. According to treatment indication, implant choice, and common complications, no significant differences between the level of hospital care and frequency of treatment were observed.

CONCLUSION

Independent of the level of hospital care and frequency of treatment, there is a trend for head-preserving angular-stable surgery with a homogenous level of treatment in Germany.

Complication rates and outcomes stratified by treatment modalities in proximal humeral fractures: a systematic literature review from 1970-2009

Background

The optimal treatment of complex, displaced proximal humeral fractures is controversial. A systematic literature review of the time period from 1970 to 2009 was conducted. The purpose was to evaluate the clinical success and complications of the available treatment modalities to determine specific treatment recommendations for the different fracture patterns.

Methods

The databases (PubMed/EMBASE) were searched for the time period (01/1970–09/2009). Study quality, treatment modalities, classification, outcome scores and complications of 200 publications including 9377 patients were analyzed. Interventions were compared by analysis of variance with subsequent Tukey’s-test. Complication rates among methods were compared by using Pearson’s-chi-square-test and pairwise comparisons using Fisher’s-two-tailed-exact-test.

Results

Hemiarthroplasty, angle-stable plate and non-operative treatment were used for 63% of the follow-up-patients. For 3- and 4-part fractures, patients with hemiarthroplasty [3-Part: 56.4 (lower/upper 95% confidence interval (CI): 43.3-68.7); 4-Part: 49.4 (CI: 42.2-56.7)] received a lower score than different surgical head-preserving methods such as ORIF [3-Part: 82.4 (CI: 76.6-86.9); 4-Part: 83.0 (CI:78.7-86.6)], intramedullary nailing [3-Part: 79.1 (CI:74.0-83.4)] or angle-stable plates [4-Part: 66.4 (CI: 59.7-72.4)].

The overall complication rate was 56%. The most common complications were fracture-displacement, malunion, humeral head necrosis and malreduction. The highest complication rates were documented for conventional plate and hemiarthroplasty and for AO-C, AO-A, for 3- and 4-part fractures. Only 25% of the data were reported with detailed classification results and the corresponding outcome scores.

Discussion

Despite the large amount of patients included, it is difficult to determine adequate recommendations for the treatment of proximal humeral fractures because a relevant lack of follow-up data impaired subsequent analysis. For displaced 3- and 4-part fractures head-preserving therapy received better outcome scores than hemiarthroplasty. However, a higher number of complications occurred in more complex fractures and when hemiarthroplasty or conventional plate osteosynthesis was performed. Thus, when informing the patient for consent, both the clinical results and the possibly expected complications with a chosen treatment modality should be addressed.

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.

Current strategies for the treatment of proximal humeral fractures: an analysis of a survey carried out at 348 hospitals in Germany, Austria, and Switzerland

BACKGROUND

The therapeutic spectrum for the treatment of displaced proximal humeral fractures ranges from conservative therapy to head-preserving surgical interventions and joint replacement. This study initiated a survey on the current treatment options with regard to diagnostics, choice of therapy, and complications that are encountered at trauma surgeries and orthopedic hospitals in Germany, Austria, and Switzerland.

MATERIALS AND METHODS

The survey included 743 hospitals. The questionnaire covered information on demographics, diagnostics, classification, therapy, and complications of proximal humeral fractures.

RESULTS

The questionnaire was completed by 348 hospitals. Five of 6 hospitals treat more than 40% of the fractures surgically. The percentage distribution of the available implants is at 63.4% for angular stable plates, 30.9% for intramedullary nails, and 10.1% for fracture prostheses. The 5 complications reported most frequently were nonanatomic reduction (83%), implant perforation (73%), secondary displacement of the fracture (71%), avascular necrosis (67%), and implant-related impingement (59%).

CONCLUSIONS

A preference for surgical treatment of proximal humeral fractures was found, with stabilization predominantly being attempted by the use of angle-stable implants. The 2 most common complications were "nonanatomic reduction of fractures" and the more specific problem of "implant perforation" when fixed-angle implants were used for treatment.

The impact of stereo-visualisation of three-dimensional CT datasets on the inter- and intraobserver reliability of the AO/OTA and Neer classifications in the assessment of fractures of the proximal humerus

We evaluated the impact of stereo-visualisation of three-dimensional volume-rendering CT datasets on the inter- and intraobserver reliability assessed by kappa values on the AO/OTA and Neer classifications in the assessment of proximal humeral fractures. Four independent observers classified 40 fractures according to the AO/OTA and Neer classifications using plain radiographs, two-dimensional CT scans and with stereo-visualised three-dimensional volume-rendering reconstructions. Both classification systems showed moderate interobserver reliability with plain radiographs and two-dimensional CT scans. Three-dimensional volume-rendered CT scans improved the interobserver reliability of both systems to good. Intraobserver reliability was moderate for both classifications when assessed by plain radiographs. Stereo visualisation of three-dimensional volume rendering improved intraobserver reliability to good for the AO/OTA method and to excellent for the Neer classification. These data support our opinion that stereo visualisation of three-dimensional volume-rendering datasets is of value when analysing and classifying complex fractures of the proximal humerus.