The Influence of Local Bone Density on the Outcome of One Hundred and Fifty Proximal Humeral Fractures Treated with a Locking Plate

How bone quality may influence intraoperative and early postoperative problems after angular stable open reduction-internal fixation of proximal humeral fractures

BACKGROUND

With the introduction of the deltoid tuberosity index (DTI), a simple radiographic tool has become available to measure bone mineral density of the proximal humerus. The aim of this study was to assess the influence of local bone mineral density on the early failure rate after angular stable open reduction-internal fixation of proximal humeral fractures (PHFs).

METHODS

We retrospectively followed up all patients treated with angular stable implants for PHFs from 2007 to 2014. The fractures were classified according to Neer, and the DTI, metaphyseal head extension (MHE), medial hinge displacement, and quality of reduction were assessed. Failures were defined as head screw cutouts.

RESULTS

The study included 146 patients (mean age, 66 years; range, 20-94 years). The mean follow-up period was 11 months (range, 3-94 months). Of the fractures, 91% were classified as 2- or 3-part fractures and 9% as 4-part fractures. The mean DTI was 1.44 (range, 1.19-2.11), and the mean MHE was 12 mm (range, 0-48 mm). The reduction result was at least acceptable in 80% of fractures. Screw cutouts were found in 23%. The DTI and MHE were the most significant preoperative predictors for the reduction result. The DTI (P = .036) and age (P = .02) were independent preoperative factors, and a good reduction (P = .001) was the only intraoperative factor influencing cutout.

DISCUSSION

This study proves that good bone quality and a long MHE are helpful for the reduction. Furthermore, good bone quality, a younger age, and a good reduction prevent later cutout. We conclude that local bone quality is a relevant factor in the treatment plan for PHFs.

Locking intramedullary nails versus locking plates for the treatment of proximal humerus fractures

INTRODUCTION

Proximal humerus fractures (PHF) are common fractures and are the third most common type of fractures among older adults. The most commonly used implants include the locking plate and the locking intramedullary nail. Areas covered: The aim of this study is to perform a literature review of biomechanical and clinical studies that compare the locking plate and intramedullary nail for PHF osteosynthesis. Expert commentary: Twelve clinical studies and seven biomechanical studies were identified that met this criterion. The findings of this review showed that intramedullary nailing and locking plate fixation yielded similar functional results, but with contrasting complication rates. The biomechanical studies showed controversial results, with most of the studies demonstrating better biomechanical properties for the intramedullary nail. Different types of intramedullary nail for PHF have different characteristics, with curvilinear nails presenting a higher risk of complications.

Management of Acute Proximal Humeral Fractures

Proximal humeral fractures, which typically occur in elderly persons, are among the most common fractures. A myriad of nonsurgical and surgical treatment options exist for these injuries, including short-term immobilization and early physical therapy, percutaneous fixation, plate osteosynthesis, intramedullary nailing, hemiarthroplasty, and reverse shoulder arthroplasty. The choice of treatment depends on the fracture type and severity, surgeon expertise, patient age, and patient health status.

Complications of locked plating for proximal humeral fractures-are we getting any better?

BACKGROUND

Complication rates reported after locking plate fixation of proximal humeral fractures still range up to 40%. Whether modifications of surgical techniques, use of primary shoulder arthroplasty, or a fracture-specific management resulted in decreased complication rates during recent years remains unclear. Therefore, the aim of this long-term observation study was to analyze the incidence of complications and revision surgery after locked plating.

METHODS

Between February 2002 and December 2013, 788 patients (aged 67.4 ± 17.3 years) with displaced proximal humeral fractures were treated with locking plate, primary hemiarthroplasty (HA), or reverse shoulder arthroplasty (RSA). Standardized follow-up included radiographs at 1 day, 6 weeks, and 3, 6, and 12 months. Complications and unplanned revision surgery were prospectively recorded over the complete follow-up.

RESULTS

Of 788 patients, 646 (82%) were treated with locking plate, 82 (10.4%) with HA, and 60 (7.6%) with RSA. Mean follow-up was 14.8 ± 3.8 months. The mean complication rate associated with locked plating was 12.8%, and revision surgery was necessary in 11.6%. Within the last 5 years, the loss of fixation rate markedly decreased from 14.3% to 4.8%; simultaneously, an increased use of RSA was observed.

CONCLUSION

The overall complication rate of locking plate osteosynthesis for proximal humeral fractures has been decreasing considerably within the last years. Among others, this might be due to an increased use of primary RSA for complex fracture types. In addition to a precise surgical technique, choosing the adequate treatment for each individual fracture to avoid complications and revision surgery is of utmost importance.

Significant Differences Between Local Reporting and Central Assessment of Radiographic Complications in a Prospective, Multicenter Study About Locking Plate Fixation of Proximal Humerus Fractures

OBJECTIVES

To compare reporting outcomes of radiographic complications conducted by an independent review board and the responsible on-site study personnel in a multicenter study about locking plate fixation of proximal humeral fractures.

DESIGN

Prospective, multicenter study; setting: 9 level I trauma centers.

PATIENTS

One hundred fifty patients (age 50-90) with a radiographically confirmed displaced proximal humeral fracture fixed with a locking plate were included in the study.

INTERVENTION

All radiographic data were reevaluated by an independent review board according to predefined criteria.

MAIN OUTCOME MEASUREMENTS

Differences in outcomes between the review board and the on-site assessment were analyzed with a paired t test. Interrater agreements between the central review board and on-site assessments were estimated by means of kappa statistics.

RESULTS

The review board revealed significantly more radiographic complications than the on-site assessment (P = 0.006), except for the complication "head necrosis." The interrater agreement was slight to moderate in all calculated categories.

CONCLUSIONS

Implementation of a complication review board using predefined criteria is recommended for clinical studies to prevent underreporting of radiographic complications by on-site assessment.

When is the stability of a fracture fixation limited by osteoporotic bone?

This article is concerned with the search for threshold values for bone quality beyond which the risk of fixation failure increased. For trochanteric fractures we recognized a BMD lower than 250mg/cm(3) as an additional risk for cut out. For medial femoral neck fractures since joint replacement surgery is available and produces excellent functional results, we see no indication for further differentiation or analysis of bone quality in relation to fracture fixation. In the area of osteoporotic vertebral body fractures, there are many experimental studies that try to identify BMD limits of screw fixation in the cancellous bone on the basis of QCT analysis. However, these values have not yet been introduced for application in clinical practice. In case of indication for surgical fixation, we favor minimally invasive, bisegmental, fourfold dorsal instrumentation with screw-augmentation for a T-value less than -2.0 SD (DXA analysis, total hip or total lumbar spine). For proximal humerus fractures, BMD value of 95mg/cm(3) could be seen as a threshold value below which the risk of failure rises markedly. In relation to osteoporotic distal radius fractures, based on our clinical experience and scientific analyses there are virtually no restrictions as far as bone quality is concerned on the application of palmar locking implants in the surgical management of distal radius fractures. Optimization of preoperative diagnostics might help to revise the treatment algorithm to take bone density into account, thus reducing the risk of failure and, at the same time, acquiring additional data for future reference.

Implicit modeling of screw threads for efficient finite element analysis of complex bone-implant systems

Finite element analysis is commonly used to assist in the development and evaluation of orthopedic devices. The physics of these models are simplified through approximations that enable more efficient simulations, without compromising the accuracy of the relative comparisons between implant designs or configurations. This study developed and evaluated a technique to approximate the behavior of a finely threaded screw using a smooth cylinder with the threads implicitly represented through interfacial contact conditions. This pseudo-threaded model was calibrated by comparing to simulations that explicitly modeled the thread geometry with frictional contact. A parametric analysis was performed with a single screw-in-bone system, five loading directions, and three Young׳s moduli that span the range of cancellous bone (200, 600, and 1,000MPa). Considering that screw cut-out from cancellous bone is a critical clinical issue in the osteoporotic proximal humerus, the pseudo-threaded model was compared with a bonded interface to examine three different screw configurations in a 3-part proximal humerus fracture across 10 patients. In the single screw-in-bone system, the pseudo-threaded model predicted the screw displacement of the explicitly threaded model with 1-5% difference and estimated the strain distributions and magnitudes more accurately than a bonded interface. Yet, the relative comparisons of implant stability across the three different screw configurations in the proximal humerus were not affected by the modeling choice for the bone-screw interface. Therefore, the bonded interface could serve as a more efficient methodology for making relative comparisons between implants that utilize the same thread profile.

The effect of local bone density on mechanical failure after internal fixation of pertrochanteric fractures

INTRODUCTION

The aim of this prospective study was to investigate the effect of local hip bone density on mechanical failure after fixation of pertrochanteric fractures and to establish possible risk factors for the failures.

MATERIALS AND METHODS

A total of 136 consecutive patients presenting a closed unilateral pertrochanteric fracture were enrolled. The patients were treated with a sliding hip screw or an intramedullary nail. Dual energy X-ray absorptiometry measurements for bone density of the contralateral hip were made within 4 weeks postoperatively. Follow-up evaluations on the standard radiographs were documented for any mechanical failure including loss of reduction, screw or blade cut-out, lateral migration of the screw or blade, and implant breakage. Secondary outcomes were also recorded including patient characteristics and fixation construct variables as possible predictors for mechanical failure.

RESULTS

At a minimum of 2 years of follow-up, 38 patients were reported with mechanical failure at an estimated risk of 27.9 %. The local bone density measurements for the study population showed no difference between patients with (0.710 g/cm(2)) and without (0.726 g/cm(2)) mechanical failure (P = 0.180). We also observed no significant correlation between local bone density and failure in patients with good fracture reduction (P = 0.862). The multivariate regression analysis identified fracture type (P < 0.001) and quality of fracture reduction (P < 0.001) as being independent predictors for mechanical failure, whereas local bone density was not (P = 0.658).

CONCLUSIONS

Local hip bone density does not appear to have a significant influence on mechanical failure after internal fixation of pertrochanteric fractures. Stable fractures and fractures with good reduction are expected to obtain satisfactory outcomes.

Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals: Significantly Reduced Bone Stock in the Metaphyseal and Subcapital Regions of Osteoporotic Individuals

Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred.The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals.The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis.At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side.This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus.

Open Reduction and Internal Fixation of Fractures of the Proximal Part of the Humerus

Introduction

We describe the surgical technique for open reduction and internal fixation (ORIF) of proximal humeral fractures with a locking plate.

Step 1 Preoperative Planning

To choose the right candidate, obtain a full understanding of the patient's fracture pattern, activity level and demands, and bone quality; be aware of predictors of complications and poor outcomes.

Step 2 Patient Positioning

Place the patient in the beach-chair position with the arm draped free or in a hydraulic device with good access for the image intensifier.

Step 3 Approach

The deltopectoral approach is generally preferred because of the exposure obtained, the possibility of distal extension, and the minimal risk of nerve injury.

Step 4 Reduction and Fixation of the Tuberosities the Key to Obtaining Marionette-Like Control

The control, reduction, and fixation of the tuberosities are crucial to restore the anterior-posterior force couple of the shoulder and must therefore be done properly no matter what the fracture pattern looks like.

Step 5 Fracture Reduction

After carrying out Steps 1 through 4, perform the reduction techniques for the specific fracture type as described below for types that we think suitable for ORIF with a locking plate.

Step 6 Fixation Implant-Specific Considerations

Plate length and positioning, humeral head screw placement, distal locking, confirming the screw tip position with the image intensifier, and securing the tuberosities.

Step 7 Tenotomy or Tenodesis of the Long Biceps Tendon

Perform a biceps tenotomy if the biceps is displaced out of the groove by the fracture pattern or if you have to open the rotator interval.

Step 8 Wound Closure

Do not close the deltopectoral interval.

Step 9 Rehabilitation

As the failure rate of ORIF of proximal humeral fractures is high, do not force an active rehabilitation protocol.

Results

In our analysis of 269 fractures followed for twelve months, we found that the Constant-Murley score (CMS) and Short Form-36 (SF-36) score improved continuously during the first six months postoperatively.IndicationsContraindicationsPitfalls & Challenges.

Deltoid Tuberosity Index: A Simple Radiographic Tool to Assess Local Bone Quality in Proximal Humerus Fractures

BACKGROUND

Osteoporosis may complicate surgical fixation and healing of proximal humerus fractures and should be assessed preoperatively. Peripheral quantitative CT (pQCT) and the Tingart measurement are helpful methods, but both have limitations in clinical use because of limited availability (pQCT) or fracture lines crossing the area of interest (Tingart measurement). The aim of our study was to introduce and validate a simple cortical index to assess the quality of bone in proximal humerus fractures using AP radiographs.

QUESTIONS/PURPOSES

We asked: (1) How do the deltoid tuberosity index and Tingart measurement correlate with each other, with patient age, and local bone mineral density (BMD) of the humeral head, measured by pQCT? (2) Which threshold values for the deltoid tuberosity index and Tingart measurement optimally discriminate poor local bone quality of the proximal humerus? (3) Are the deltoid tuberosity index and Tingart measurement clinically applicable and reproducible in patients with proximal humerus fractures?

METHODS

The deltoid tuberosity index was measured immediately above the upper end of the deltoid tuberosity. At this position, where the outer cortical borders become parallel, the deltoid tuberosity index equals the ratio between the outer cortical and inner endosteal diameter. In the first part of our study, we retrospectively measured the deltoid tuberosity index on 31 patients (16 women, 15 men; mean age, 65 years; range, 22-83 years) who were scheduled for elective surgery other than fracture repair. Inclusion criteria were available native pQCT scans, AP shoulder radiographs taken in internal rotation, and no previous shoulder surgery. The deltoid tuberosity index and the Tingart measurement were measured on the preoperative internal rotation AP radiograph. The second part of our study was performed by reviewing 40 radiographs of patients with proximal humerus fractures (31 women, nine men; median age, 65 years; range, 22-88 years). Interrater (two surgeons) and intrarater (two readings) reliabilities, applicability, and diagnostic accuracy were assessed.

RESULTS

The correlations between radiograph measurements and local BMD (pQCT) were strong for the deltoid tuberosity index (r = 0.80; 95% CI, 0.63-0.90; p < 0.001) and moderate for the Tingart measurement (r = 0.67; 95% CI, 0.42-0.83; p < 0.001). There was moderate correlation between patient age and the deltoid tuberosity index (r = 0.65; p < 0.001), patient age and the Tingart measurement (r = 0.69; p < 0.001), and patient age and pQCT (r = 0.73; p < 0.001). The correlation between the deltoid tuberosity index and the Tingart measurement was strong (r = 0.84; p < 0.001). We determined the cutoff value for the deltoid tuberosity index to be 1.44, with the area under the curve = 0.87 (95% CI, 0.74-0.99). This provided a sensitivity of 0.88 and specificity of 0.80. For the Tingart measurement, we determined the cutoff value to be 5.3 mm, with the area under the curve = 0.83 (95% CI, 0.67-0.98), which resulted in a sensitivity of 0.81 and specificity of 0.85. The intraobserver reliability was high and not different between the Tingart measurement (intraclass correlation coefficients [ICC] = 0.75 and 0.88) and deltoid tuberosity index (ICC = 0.88 and 0.82). However, interobserver reliability was higher for the deltoid tuberosity index (ICC = 0.96; 95% CI, 0.93-0.98) than for the Tingart measurement (ICC = 0.85; 95% CI, 0.69-0.93).The clinical applicability on AP radiographs of fractures was better for the deltoid tuberosity index (p = 0.025) because it was measureable on more of the radiographs (77/80; 96%) than the Tingart measurement (69/80; 86%).

CONCLUSIONS

The deltoid tuberosity index correlated strongly with local BMD measured on pQCT and our study evidence shows that it is a reliable, simple, and applicable tool to assess local bone quality in the proximal humerus. We found that deltoid tuberosity index values consistently lower than 1.4 indicated low local BMD of the proximal humerus. Furthermore, the use of the deltoid tuberosity index has important advantages over the Tingart measurement regarding clinical applicability in patients with proximal humerus fractures, when fracture lines obscure the Tingart measurement landmarks. However, further studies are needed to assess the effect of the deltoid tuberosity index measurement and osteoporosis on treatment and outcome in patients with proximal humerus fractures.

LEVEL OF EVIDENCE

Level IV, diagnostic study.

Digital Tomosynthesis to Evaluate Fracture Healing: Prospective Comparison With Radiography and CT

OBJECTIVE

Radiography, currently the standard for postoperative fracture imaging, is limited by overlapping bone and hardware. Tomosynthesis has the benefit of level-by-level imaging without the disadvantages of metal artifacts, increased radiation, and higher costs of CT, the current problem-solving tool. The purpose of this study was to compare tomosynthesis with radiography for evaluating fracture healing.

SUBJECTS AND METHODS

In a prospective study, patients within 1 year of wrist hardware fixation underwent radiography, tomosynthesis, and CT, and the images were interpreted by three readers. The diagnostic accuracy of radiology and tomosynthesis was assessed with ROC curves, and interreader agreement was assessed with Cohen kappa. Fracture scores were correlated with Disabilities of the Arm, Shoulder, and Hand (DASH) and pain scores.

RESULTS

The study participants were 49 patients with 51 fractures. The most common fracture sites were distal radius (43%), scaphoid (18%), and metacarpals (18%). Rates of cortex obscuration by hardware were 2% for CT, 8% for tomosynthesis, and 15% for radiography (p < 0.01 between one modality and another). Detection of cortical fracture lines was significantly better with tomosynthesis than with radiography (AUC, 0.84 vs 0.76, p = 0.01). Inter-reader agreement was moderate for both radiography and tomosynthesis (κ = 0.44 vs 0.55, p = 0.051). There was no significant correlation between fracture scores and DASH scores. There was significant correlation between reported pain levels and both tomosynthesis (r = 0.28, p = 0.03) and CT (r = 0.29, p = 0.04) fracture scores.

CONCLUSION

Tomosynthesis provides diagnostic information superior to that of ra diography in postoperative evaluation of wrist fractures with lower cost and radiation than CT and should be considered in fracture follow-up imaging of other bones.

Mid-term results of a less-invasive locking plate fixation method for proximal humeral fractures: a prospective observational study

Background

The optimal treatment for proximal humeral fractures remains under debate. In this article, we report the mid-term results of patients who underwent the less-invasive implantation of a polyaxial locking plate for displaced proximal humeral fractures.

Methods

This study included patients who were treated with a polyaxial locking plate via an anterolateral deltoid split approach from May 2008 to December 2011. We evaluated outcome parameters after a minimum follow-up period of 2.5 years (median 4.5 years, follow-up rate 62 %) including the age- and gender-dependent Constant score, the activities of daily living score, and the visual analog scale for both pain and subjective shoulder function.

Results

Of the 140 patients who underwent surgery, 114 were included in the follow-up and 71 completed the questionnaire. Fifteen patients (21 %) exhibited 2-fragment fractures, and 56 patients (79 %) exhibited 3- and 4-part fractures. The Constant score improved significantly (4.5 years: 70 ± 21, p < 0.001) between the first two follow-ups (6 weeks: 35 ± 14, 6 months: 56 ± 18, p < 0.001), and also between 6 months and 4.5 years post-surgery. At the final follow-up, the activities of daily living score had not reached pre-fracture levels (before trauma: 27 ± 5, 4.5 years: 20 ± 8, p < 0.001). A multivariate analysis showed that age has a more significant influence on the final outcome than fracture morphology or gender.

Conclusion

Although the less-invasive surgical procedure is a feasible treatment option in proximal humeral fractures with acceptable complications and considerable improvement during the first six months, a lengthy recovery time is required. The majority of our patients did not become pain-free or reach pre-fracture activity levels.