Evaluation of intramedullary rib splints for less-invasive stabilisation of rib fractures

Background

Intramedullary fixation of rib fractures with generic Kirschner wires has been practiced for over 50 years. However, this technique has not been advanced to address reported complications of wire migration and cut-out. This biomechanical study evaluated a novel rib splint designed to replicate the less-invasive fixation approach of Kirschner wires while mitigating their associated complications.

Methods

The durability, strength, and failure mode of rib fracture fixation with intramedullary rib splints were evaluated in 27 cadaveric ribs. First, intact ribs were loaded to failure to determine their strength and to induce realistic rib fractures. Subsequently, fractures were stabilised with a novel rib splint made of titanium alloy with a rectangular cross-section that was secured with a locking screw. All fixation constructs were dynamically loaded to 360,000 cycles at five times the respiratory load magnitude to determine their durability. Finally, constructs were loaded to failure to determine their residual strength and failure modes.

Results

Native ribs had a strength of 9.7 ± 5.0 N m, with a range of 3.5-19.6 N m. Fracture fixation with rib splints was uneventful. All 27 splint constructs sustained dynamic loading without fixation failure, implant migration or implant cut-out. Dynamic loading caused no significant decrease in construct stiffness (p = 0.85) and construct subsidence remained on average below 0.5 mm. The residual strength of splint constructs after dynamic loading was 1.1 ± 0.24 N m. Constructs failed by splint bending in 44% of specimens and by developing fracture lines along the superior and inferior cortices in 56% of specimens. Regardless of the failure mode, all rib splint constructs recoiled elastically after failure and retained functional reduction and fixation. No construct exhibited implant cut-out or migration through the lateral cortex.

Conclusions

Rib splints can provide sufficient stability to support respiratory loading throughout the healing phase, but they cannot restore the full strength of native ribs. Most importantly, rib splints mitigated the complications reported for rib fracture fixation with generic Kirschner wires, namely implant cut-out and migration through the lateral cortex. Therefore, rib splints may provide an advanced alternative to the original Kirschner wire technique for less-invasive fixation of rib fractures.     

Rib fracture as a predictor of future fractures in young and older postmenopausal women: National Osteoporosis Risk Assessment (NORA)

Summary  

A rib fracture history after age 45 was associated with a 5.4-fold increase in new rib fracture risk and a 2.4-fold increase in risk of any new clinical fracture in 155,031 postmenopausal women. A rib fracture history suggests osteoporosis and should be considered when evaluating patients for interventions to prevent fractures.     

Stabilization of multiple rib fractures in a canine model

Background

Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF.

Methods

Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures.

Results

No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization.

Conclusions

Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries.     

The virtual isocentric aiming device: a new mechanical targeting concept

Introduction  

Minimally invasive fracture fixation can be technically demanding, especially in body regions characterised by complex bone anatomy and the presence of a significant amount of soft tissue. Hence, this procedure is associated with a high risk of implant malposition. As a consequence, radiation exposure to the patient and the surgeon increases within surgery.     

Comparative study of two materials for dynamic hip screw during fall and gait loading: titanium alloy and stainless steel

Background  

Internal fixation with dynamic hip screw is a choice of treatment for hip fractures to stabilize a femoral fracture. Choosing the proper implant and its material has a great effect on the healing process and failure prevention. The purpose of this analysis was to assess biomechanical behavior of dynamic hip screw with two different materials implanted in the femur during fall and gait.     

Pertrochanteric fractures: tips and tricks in nail osteosynthesis

Introduction

Intramedullary fixation of intertrochanteric fractures has become the standard method of fixation especially in unstable fracture types. Even though there have been developments on implant design and technology, the surgical technique of reduction and implant positioning remains the mandatory factor in treating these fractures successfully. The advantages of nailing in the mainly elderly patients sustaining intertrochanteric femur fractures are a short lever arm and a lateral support in the trochanter supplied by the nail. The disadvantages are that it is often harder to achieve a closed reduction of a displaced fracture and to maintain the reduction with the intramedullary implant.

Tips and tricks

To obtain and maintain anatomic reduction and a secure fracture fixation, the surgical approach and fixation technique is of great importance. It starts with correct patient positioning, fracture reduction (accounting for varus dislocation and dislocation of flexed fragments), choosing the correct nail entry point and perfect lag screw positioning within the head-neck fragment and distal locking. To maintain the reduction achieved intraoperatively, the decision has to be made to use a cerclage wiring or to tolerate fracture gaps in the metaphyseal area. Intraoperative controlled compression of the neck or the subtrochanteric area is of great importance to reduce delayed unions or nonunions.

Summary

Intramedullary fixation of unstable per-, inter- or subtrochanteric fractures shows biomechanical advantages compared to extramedullry fixation techniques. Even though there have been several amendments and developments of implants, a better implant does not compensate for an inadequate surgical approach or deficient surgical techniques which are paramount for successful treatment. When fixing fractures with intramedullary nailing systems, the surgeon should always try to achieve anatomic reduction and a perfect implant positioning to allow immediate full weight bearing without an increased risk of cut-out, non-union and implant failure.     

Initial promising results of the dynamic locking blade plate,a new implant for the fixation of intracapsular hip fractures: results of a pilot study

Introduction  

The osteosynthesis of intracapsular hip fractures results in a 19–48% failure rate. Only when the anatomical reduction is secured by stable fixation, revascularisation of the femoral head can take place and the fracture can heal by primary osteonal reconstruction. The common implants lack rotational and/or angular stability. Also the relative large volume of the implants within the femoral head compromises the (re)vascularisation. The combination of an anatomical reduction and a low volume, dynamic implant, providing angular and rotational stability seem to be crucial factors in the treatment of intracapsular hip fractures. This assumption formed the starting point for the development of the dynamic locking blade plate (DLBP), a new implant for the internal fixation of intracapsular hip fractures. This report describes the first clinical results of the new implant.     

Surgical treatment and management of hip fracture patients

Introduction

Osteoporosis-related hip fractures are associated with high mortality and costs. The optimum type of treatment for such fractures is controversial. To shed some light on this issue, the surgical treatment and management of osteoporotic hip fractures were discussed during a hip fracture surgical working group at the 2009 International Society For Fracture Repair Annual Meeting comprising leading experts in the field.

Materials and methods

The working group consisted of eight orthopaedic surgeons, six industry representatives and one research scientist. Eleven participants were from Europe and four were from the USA and Canada. Two chairmen posed 12 questions relating to the surgical treatment and management of osteoporotic hip fractures. Each question was discussed and key points were noted.

Results

Surgery should commence within 24–48 h but the patient should be optimized if presenting with ≥3 comorbidities. Specialized centres integrating orthopaedics, geriatricians and rheumatologists could be a solution for the lack of specialist care post-surgery. Surgical technique is important in fracture fixation, as is the implant, but there has been no improvement in implant design in the past 50 years. As a consequence, malunion has become unjustifiably accepted. Fracture healing can be accelerated using pharmaceuticals which are also important in secondary prophylaxis. All displaced femoral neck fractures in geriatric patients should be treated with hip replacement, the choice between using cemented or uncemented fixation being at the surgeon’s discretion.

Discussion and conclusion

This working group discussion highlighted several important issues which could be of interest to the orthopaedic community.     

The Otto Aufranc Award: Demineralized Bone Matrix Around Porous Implants Promotes Rapid Gap Healing and Bone Ingrowth

Background  

Noncemented revision arthroplasty is often complicated by the presence of bone implant gaps that reduce initial stability and biologic fixation. Demineralized bone matrix has osteoinductive properties and therefore the potential to enhance gap healing and porous implant fixation.     

Results of the femur fractures treated with the new selfdynamisable internal fixator (SIF)

Purpose  

As axial dynamisation is a recognised method, many authors using interlocking femoral nail perform an additional small operation two months after the primary operation in order to remove one screw so as to provide axial dynamisation. According to the literature, dynamisation happens in about 15–25% of cases, but it cannot be predicted which patient or fracture will need dynamisation. The aim of this study is to present a new selfdynamisable implant and a minimally invasive method for the internal fixation of different femoral fractures.     

Bisphosphonate Remains Highly Localized After Elution From Porous Implants

Background  

Local elution of zoledronic acid from a porous implant reportedly enhances periimplant bone formation and implant fixation. However, there is no information in the literature on the extent to which eluted bisphosphonate remains localized around the implant or becomes systemically distributed.     

THA After Acetabular Fracture Fixation: Is Frozen Section Necessary?

Background  

Infection is uncommon after THA performed for failed acetabular fracture repair, despite a high reported incidence of culture-positive fixation implants. The use of frozen section analysis at the time of THA after acetabular fracture fixation surgery is unknown.     

Implant removal associated complications in children with limb fractures due to trauma

Purpose  

The purpose of this study was to analyze the number and type of complications that occurred after fracture implant removal and to investigate whether implant removal should be performed routinely in children.     

Computed tomographic evaluation of odontoid process: implications for anterior screw fixation of odontoid fractures in an adult population

Introduction  

Odontoid diameter in some individuals may not be large enough to accommodate two 3.5-mm cortical screws for anterior odontoid fracture fixation. The study was performed to evaluate, in a Brazilian population, the diameter of the odontoid process and the feasibility of using two 3.5-mm cortical screws for anterior odontoid fracture fixation.     

Medial scapular winging associated with rib fractures and plating corrected with pectoralis major transfer

INTRODUCTION

Rib plating is becoming increasingly common as a method for stabilizing a flail chest resulting from multiple rib fractures. Recent guidelines recommend surgical stabilization of a flail chest based on consistent evidence of its efficacy and lack of major safety concerns. But complications of this procedure can occur and are wide ranging.

PRESENTATION OF CASE

We report an interesting case of a 58-year-old male patient that worked as a long-distance truck driver and had a flail chest from multiple bilateral rib fractures that occurred when his vehicle was blown over in a wind storm. He underwent open reduction with internal fixation (ORIF) of the bilateral rib fractures and they successfully healed. However, he had permanent long thoracic nerve injury on the side with the most severe trauma. This resulted in symptomatic scapular winging that impeded him from long-distance truck driving. The scapular winging was surgically corrected nearly two years later with a pectoralis major transfer augmented with fascia lata graft. The patient had an excellent final result.

DISCUSSION

We report this case to alert surgeons who perform rib fracture ORIF that long thoracic nerve injury is a potential iatrogenic complication of that procedure or might be a result of the chest wall trauma.

CONCLUSION

Although the specific cause of the long thoracic nerve injury could not be determined in our patient, it was associated with chest wall trauma in the setting of rib fracture ORIF. The scapular winging was surgically corrected with a pectoralis major transfer.     

Minimally Invasive 360° Fusion Using a Combination of INFIX and Minimally Invasive Spinopelvic Fixation by Intraoperative Computed Tomography Navigation for Unstable Pelvic Ring Fracture: A Technical Note

Objective

Fluoroscopy is often used in the surgery of unstable pelvic ring fractures, and improved safety in implant placement is an issue. An anterior subcutaneous pelvic fixator (INFIX) combined with a percutaneous screw has been reported to be a minimally invasive and effective surgical technique for unstable pelvic ring injuries. However, although percutaneous screw fixation is minimally invasive, its indications for fracture fixation and fractures with large fragment displacements in the vertical plane remain controversial. Therefore, this technical note aims to describe a new technique for unstable pelvic ring fractures.

Methods

We describe a 360° fusion of the pelvic ring to treat unstable pelvic ring fractures, including vertical shear pelvic ring fractures, using an intraoperative CT navigation system. Seven patients were treated with 360° fusion for type C pelvic ring fractures. In surgery, after reducing the fracture with external fixation, intraoperative CT navigation is used to perform a 360° fusion with INFIX and minimally invasive surgical spinopelvic fixation (MIS-SPF). We will introduce a typical case and explain the procedure.

Results

A 360° fixation was performed, and no perioperative complications were noted. The mean blood loss was 253.2 ± 141.0 mL, and the mean operative time was 224.3 ± 67.4 min. In a typical case, bone union was obtained 1 year after surgery, and we removed all implants.

Conclusions

MIS-SPF has a strong fixation force and helps reduce fractures' horizontal and vertical planes. In addition, 360° fusion with intraoperative CT navigation may help treat unstable pelvic ring fractures.     

Excessive Complications of Open Intramedullary Nailing of Midshaft Clavicle Fractures With the Rockwood Clavicle Pin

Background  

Intramedullary clavicle fixation is a potential alternative to plate fixation. Previous studies documenting the complication rates of intramedullary clavicle fixation have demonstrated variable rates of soft tissue complications and fracture healing.     

An Innovative Model of ISS-Based Multiple Fractures and Gastrointestinal Dysfunction Related to c-Kit Protein Expression on Interstitial Cells of Cajal

Objective

Gastrointestinal dysfunction seriously affects the prognosis and quality of life of patients with multiple fractures. However, experimental evidence of this relationship is lacking. Here we describe a newly developed mouse model of postoperative gastrointestinal dysfunction after multiple fractures.

Methods

Trauma severity was assessed using the injury severity score (ISS). Based on the ISS, a multiple fracture model was established in mice as follows: limb fractures with pelvic fractures and multiple rib fractures; limb fractures with multiple rib fractures; closed fracture of both forelegs with pelvic fracture and rib fractures; closed limb fractures; limb fracture with pelvic fracture; spinal fractures; hind leg fractures with pelvic fractures; pelvic fracture with multiple rib fractures; closed fracture of both fore legs with pelvic fracture; and closed fracture of both fore legs with multiple rib fractures. In each model group, gastrointestinal motility was assayed and the histopathology of the small intestine was examined. Western blot and immunohistochemical analyses of jejunal tissue were performed to detect c-kit protein expression, the level of which was compared with that of a control group. The results of ANOVA are expressed as mean ± standard deviation.

Results

In mice with multiple fractures, food intake was greatly reduced, consistent with histopathological evidence of an injured intestinal epithelium. The jejunal tissue of mice in groups a, c, f, and h was characterized by extensively necrotic and exfoliated intestinal mucosal epithelium and inflammatory cell infiltration in the lamina propria. In the gastrointestinal function assay, gastrointestinal motility was significantly reduced in groups a, b, c, f, and g; these group also had a higher ISS (p < 0.01). The expression of c-kit protein in groups with gastrointestinal dysfunction was significantly up-regulated (p < 0.001) compared with the control group. The close correlation between c-kit expression and the ISS indicated an influence of trauma severity on gastrointestinal motility.

Conclusion

Gastrointestinal dysfunction after multiple fractures was successfully reproduced in a mouse model. In these mice, c-kit expression correlated with gastrointestinal tissue dysfunction and might serve as a therapeutic target.     

The Humerusblock NG: a new concept for stabilization of proximal humeral fractures and its biomechanical evaluation

Background

The Humerusblock NG represents a new semi-rigid angular stable fixation device for minimally invasive stabilization of proximal humeral fractures. This study evaluates the function and stability of the Humerusblock NG and its biomechanical properties on the basis of two different fracture models under cyclic loading.

Methods

Six fresh frozen human humeri were tested in a dynamic shoulder joint abduction motion test bench, simulating abduction between 15° and 45°. A stable wedge fracture with intact medial hinge and an unstable fracture with 5-mm gap were loaded for 500 cycles. Radiological measurement of implant migration was performed.

Results

The stable fracture model showed a slow constant fracture settling. The unstable fracture model showed initial fracture settling with closure of the medial fracture gap during the first 20 cycles. Thereafter, a slow constant settling of the fracture was measured comparable to the stable fracture model. Maximum varus tilt was 3.17° for the stable and 3.68° for the unstable fracture pattern. Radiological analysis showed no change in the tip apex distance and a significant settling of the implants fixation pins in the unstable fracture model. None of the specimen failed during the testing.

Conclusion

The Humerusblock NG allows for angular stable dynamic fixation of two-part proximal humeral fractures. It enables closure of the fracture gap and maintains fracture compression during loading, a concept already established in the stabilization of femoral neck fractures (dynamic hip screw). Clinical trials will be necessary to evaluate the value of this device in daily practice.

Level of evidence

Basic science study.     

Displaced proximal humeral fractures: an Indian experience with locking plates

Background  

The treatment of displaced proximal humerus fractures, especially in elderly, remains controversial. The objective of this study was to evaluate functional outcome of locking plate used for fixation of these fractures after open reduction. We also attempted to evaluate the complications and predictors of loss of fixation for such an implant.