Antegrade versus retrograde titanium elastic nail fixation of pediatric distal-third femoral-shaft fractures: a mechanical study

External fixator versus elastic stable intramedullary nail for treatment of metaphyseal-diaphyseal junction fractures of the pediatric distal femur: a case-control study

BACKGROUND

Several methods have been used for the treatment of pediatric distal femoral fractures, such as elastic stable intramedullary nail (ESIN), external fixator (EF) and plate osteosynthesis, but there has been no consensus about the optimal method. The purpose of this study was to compare the clinical outcome between EF and ESIN techniques used in metaphyseal-diaphyseal junction (MDJ) fractures of the pediatric distal femur.

METHODS

We retrospectively analyzed operatively treated MDJ fractures of pediatric distal femur between January 2015 and January 2022. Patient charts were reviewed for demographics, injury and data of radiography. All of the patients were divided into EF and ESIN groups according to the operation techniques. Malalignment was defined as more than 5 degrees of angular deformity in either plane. Clinical outcomes were measured by Flynn scoring system.

RESULTS

Thirty-eight patients were included in this study, among which, 23 were treated with EF, and 15 with ESIN. The mean follow-up time was 18 months (12-24 months). At the final follow-up, all of the fractures were healed. Although there were no statistical differences between the two groups in demographic data, length of stay, estimated blood loss (EBL), rate of open reduction, time to fracture healing and Flynn score, the EF was superior to ESIN in operative time, fluoroscopic exposure and time to partial weight-bearing. The EF group had a significantly higher rate of skin irritation, while the ESIN had a significantly higher rate of malalignment.

CONCLUSION

EF and ESIN are both effective methods in the treatment of MDJ fractures of the pediatric distal femur. ESIN is associated with lower rates of skin irritation. However, EF technique has the advantages of shorter operative time, reduced fluoroscopic exposure, and shorter time to partial weight-bearing, as well as lower incidence of malalignment.

LEVEL OF EVIDENCE

Level III.

Diaphyseal Femur Fractures in Children and Adolescents-Opportunities and Limitations of the ESIN Technique

Background: Elastic stable intramedullary nailing (ESIN) is the gold standard for non-overweight children aged 6−12 years. However, the complication rate using elastic stable intramedullary nailing is considerably high. Nevertheless, the question arises of whether the indication for elastic stable intramedullary nailing therapy can be extended and which factors must be taken into account when determining the indication. Methods: A retrospective chart review of patients <18 years admitted with diaphyseal femur fracture at a Level I Trauma Center in Germany between 2005 and 2017 was performed. In total, 118 patients were included. For the classification of femur fractures in children, the AO Pediatric Comprehensive Classification of Long-Bone Fractures (AO-PCCF) was applied. Results: Simple oblique fractures (32-D/5.1) occurred in most of the patients. Patients with simple oblique fractures were significantly younger compared to patients with simple transverse (32-D/4.1) or multifragmentary (32-D/5.2) fracture type according to the AO Pediatric Comprehensive Classification of Long-Bone Fractures. Most patients were treated with elastic stable intramedullary nailing (68 patients, 58%). Although children treated with elastic stable intramedullary nailing were older than those treated conservatively (25%, n = 29, mean age 1.5, median age 1.0), the children in the elastic stable intramedullary nailing group were comparatively young (range 1−12 years, mean age 5.4, median age 5). A total of 32 children below the age of 6 years were treated with elastic stable intramedullary nailing. Complications were more frequent in patients with overhead extension (50%) compared to conservative treatment with a spica cast (17%) or elastic stable intramedullary nailing (15%). Conclusions: Elastic stable intramedullary nailing therapy was associated with a low complication rate and was, therefore, a safe and frequently used treatment strategy in diaphyseal femur fractures with satisfactory results, even though the age groups were expanded in favor of younger patients.

Displaced distal femur metaphyseal fractures: clinical and radiographic outcome in children aged 6-16 years treated by elastic stable intramedullary nailing

Fractures of the distal femur metaphysis (DFM) are rare. The main objective of this study was to retrospectively evaluate the clinical and radiographic outcomes of displaced DFM fractures in children treated by elastic stable intramedullary nailing (ESIN). We retrospectively reviewed 24 DFM fractures, including five pathological fractures secondary to non-ossifying fibroma (mean age, 10.9 years; range, 6-16) who underwent surgical treatment by ESIN. The patients were followed radiographically and clinically on a regular basis. Sixteen boys and eight girls were included in the study. Radiographically, all fractures healed, but five healed with complications. Most of the DFM fractures were transverse (n = 18, 75%), and all patients but two (91.7%) underwent closed reduction and stabilization of the fracture. All the patients were pain-free at their last follow-up. All regained full normal activities, although five patients developed a postoperative complication (20.8%). At the last follow-up visit, all fractures achieved union including the two cases of nonunion; moreover, none of the patients showed any signs of growth arrest or disturbances in radiological and clinical assessment. On the ESIN outcome measure scale, 12/24 patients (50%) had excellent results, 11/24 (45.8%) had good-satisfactory results and 1/24 (4.2%) had poor results. Fracture of the DFM can be challenging due to the relatively short length of the distal fragment, the proximity of the growth plate and the tendency of the distal fragment to displace. Following the surgical principles and understanding the anatomical constraints of the distal femur help to obtain satisfactory clinical and radiological results.

Pediatric Femoral Shaft Fracture: An Age-Based Treatment Algorithm

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Distal third femoral shaft fractures in school-aged children: A comparative study of elastic stable intramedullary nail and external fixator

Internal fixation such as elastic stable intramedullary(ESIN) nail and submuscular plate (SMP) is gaining popularity for femoral shaft fractures in school-aged children. However, external fixation (ExFix) might be a valuable option for the distal third femoral shaft fractures, where the fracture heals rapidly, but it is crucial to avoid angular malunion. This study aims to compare the clinical outcomes, postoperative complications of distal third femoral shaft fractures in school-aged children treated by ESIN versus ExFix.Patients aged 5 to 11 years with distal third femoral shaft fractures treated at our institute from January 2014 to January 2016 were included and categorized into ESIN (n = 33) and ExFix (n = 38) group. The preoperative data, including baseline information of the patients, radiographic parameters, and type of surgical procedure, were collected from the hospital database, and postoperative data, including complications, were collected during the follow-up visit.In all, 33 patients (average, 8.0 ± 2.1 years, male 20, female 13) in the ESIN group and 38 patients (average, 8.3 ± 2.3 years, male 23, female 15) in the ExFix group were included in this study. There was significantly less operative time for the ExFix group (45.4 ± 7.8 min) as compared to the ESIN group (57.8 ± 11.3 min) (P < .01), reduced estimated blood loss (EBL) in the ExFix group (9.9 ± 3.5) as compared to the ESIN group (16.4 ± 6.5) (P < .01). As for the frequency of fluoroscopy, there was a significant difference between the ExFix group (13.9 ± 2.4) and the ESIN group (15.5 ± 3.2) (P = .02). The rate of major complications was not significantly different between the 2 groups (P = .19). The rate of implant irritation was significantly higher in the ExFix group (28/38, 73.7%) than the ESIN group (12/33, 36.4%) (P < .01). The rate of surgical site infection (SSI) is significantly higher in the ExFix group (18/38, 47.4%)) than the ESIN group (1/33, 3%) (P < .01). The rate of scar concern was significantly higher in the ExFix (9/38, 23.7%) than the ESIN (2/33, 6.1%), (P = .04). According to the Flynn scoring system, 30(90.9%) patients in the ESIN group and 24(89.5%) patients in the ExFix group were rated as excellent. None of the patients had poor outcomes.Both ESIN and ExFix produced satisfactory outcomes in distal third femoral shaft fractures. ExFix remains a viable choice for selected cases, especially in resource-challenged and austere settings.

Retrograde Stainless Steel Flexible Nails Have Superior Resistance to Bending in Distal Third Femoral Shaft Fractures

BACKGROUND

It has been shown that retrograde titanium flexible intramedullary nails (Ti FIN) provide superior resistance to bending compared to antegrade Ti FIN in distal femur fractures. The purpose of this study was to compare resistance to torsional and bending forces of stainless steel (SS) FIN, with or without a locking screw, and Ti FIN in distal third femoral shaft fractures. We hypothesize that locked retrograde SS FIN will demonstrate greater resistance to both bending and torsional forces.

METHODS

Thirty adolescent synthetic femur models were used to simulate transverse distal femoral fractures at either 60 mm or 90 mm proximal to the distal femoral physis. The femurs were instrumented with antegrade Ti FIN, antegrade SS FIN, retrograde Ti FIN, retrograde SS FIN, or retrograde locked SS FIN. Three models for each construct at both osteotomy levels were tested. Models were analyzed to determine maximum resistance to bending and torsion.

RESULTS

In fractures 60 mm from the physis, retrograde SS FIN demonstrated statistically superior resistance to bending when compared with both antegrade and retrograde Ti FIN (P=0.001 and 0.008, respectively) and antegrade SS FIN (P=0.0001). Locked SS constructs showed a trend towards greater resistance to bending forces when compared with unlocked constructs (P>0.05). No significant difference was seen in resistance to bending when fractures were 90 mm proximal to the distal femoral physis between the five groups. No significant differences were observed in resistance to torsion in either the proximal or distal fracture models, regardless of construct type.

CONCLUSIONS

Retrograde SS FIN confer significantly greater resistance to bending forces for fractures 60 mm proximal to the distal femoral physis compared with Ti FIN or antegrade entry SS FIN. In fractures 90 mm from the physis, no differences were noted in our model. Our results support the use of retrograde SS nails in the pediatric patient with distal femoral shaft fractures.

LEVEL OF EVIDENCE

Level II-comparative biomechanical study.

Biomechanical Analysis of Retrograde Flexible Intramedullary Nail Constructs in a Simulated Pediatric Femur Fracture Model

BACKGROUND

Various flexible intramedullary nail (FIMN) constructs for pediatric femur fractures are described; however, no biomechanical study has compared stability of medial-lateral entry versus all-lateral entry retrograde nailing. Our purpose is to compare the rotational and bending stiffness of 2 different FIMN constructs and 2 different materials in a simulated pediatric femur fracture model.

METHODS

Eighty adolescent-sized composite femurs were used to simulate transverse (40 femurs) and oblique (40 femurs) mid-diaphyseal fractures. Retrograde FIMN of the femurs was performed using either 3.5 mm titanium (Ti) or 3.5 mm stainless-steel (SS) flexible nails in 2 configurations: 2 "C"-shaped nails (CC) placed through medial and lateral entry sites or 1 "C"-shaped nail and 1 "S"-shaped nail (CS) placed through a single lateral entry site. Models were first tested in 10 cycles of axial rotation to ±1 N m of torque at a rate of 0.5 degrees/s under 36 kg of compression. Axial compression was performed and bending stiffness defined as the force required to achieve 10 degrees varus at the fracture site.

RESULTS

No differences were noted in rotational stiffness comparing Ti and SS nails regardless of nail configuration or fracture pattern. Comparable rotational stability was found for CC and CS configurations with SS implants for both fracture patterns. The CS construct (0.60 N m/degree) was stiffer in rotation than the CC construct (0.41 N m/degree) with Ti implants in the transverse fracture model (P<0.005). SS nails provided greater bending stiffness than Ti nails in both oblique and transverse fracture patterns, regardless of nail construct. The all-lateral entry (CS) construct demonstrated statistically significant greater bending stiffness regardless of implant material or fracture pattern (P<0.03).

CONCLUSIONS

An all-lateral entry (CS) FIMN construct demonstrated greater bending stiffness in both fracture patterns and materials. Ti and SS implants have comparable rotational stiffness in all fracture patterns and materials; however, SS nails were superior at resisting bending forces in both fracture patterns. CS nail configuration and SS implants demonstrated superior bending stiffness and rotational stiffness when compared with the more commonly used CC construct and Ti implants.

LEVEL OF EVIDENCE

NA (biomechanical study).

The effect of canal fill on paediatric femur fractures treated with titanium elastic nails

PURPOSE

Traditional teaching for fixation of paediatric femur fractures recommends 80% nail diameter/medullary canal diameter ratio (ND/MCD) for successful maintenance of reduction. Prior studies have investigated this with stainless steel Enders nails. Our aim was to assess the impact of ND/MCD on maintenance of reduction and malunion rates in paediatric femur fractures treated with flexible intramedullary nails (FINs).

METHODS

Retrospective data was collected on all paediatric patients treated with FINs for diaphyseal femur fractures at a single tertiary care institution over a ten-year period. Patients with co-morbidities affecting bone quality were excluded. Patients were subdivided into groups based on ND/MCD.

RESULTS

A total of 66 patients met inclusion criteria. Mean ND/MCD was 76.3% (32.9% to 98.8%, SD 14.3). In all, 50% (n = 33/66) of patients had > 80% ND/MCD, and only 13.6% (n = 9/66) of patients had less than 60% ND/MCD. When controlling for fracture stability, ND/MCD had no correlation with mean shortening (p = 0.07) There was no correlation between ND/MCD and angulation in the sagittal (p = 0.96) or coronal plane (p = 0.20). Three patients fit malunion criteria. ND/MCD for these patients were 40%, 67% and 79%.

CONCLUSION

There was no correlation between ND/MCD and shortening or malangulation. The majority of patients in this series with less than 80% fill with FIN healed within acceptable parameters.

LEVEL OF EVIDENCE

III.

The Community Orthopaedic Surgeon Taking Trauma Call: Pediatric Femoral Shaft Fracture Pearls and Pitfalls

Pediatric femoral shaft fractures present many challenging patient care decisions. Nonoperative treatment approaches still dominate care of the youngest age groups while surgical intervention is commonplace in virtually all older children. Treatment is determined primarily by patient age as modified by clinical factors including mechanism of injury, weight, and skeletal maturity. Infants can be successfully treated by placement into a Pavlik harness, whereas children younger than 5 years are most commonly treated by early reduction and spica cast immobilization. Children aged up to 11 years are most commonly treated by flexible intramedullary nailing, whereas older children and adolescents, particularly with length unstable fractures should be treated with more rigid fixation such as lateral entry locked nails or submuscular plating.

V, RHH A, Khurana A. Current Concepts in Paediatric Femoral Shaft Fractures

Pediatric femoral shaft fractures account for less than 2% of all fractures in children. However, these are the most common pediatric fractures necessitating hospitalization and are associated with prolonged hospital stay, prolonged immobilization and impose a significant burden on the healthcare system as well as caregivers. In this paper, the authors present a comprehensive review of epidemiology, aetiology, classification and managemement options of pediatric femoral shaft fractures.

Short, double elastic nailing of severely displaced distal pediatric radial fractures: A new method for stable fixation

RATIONALE

Short double elastic nailing is a minimal invasive, modified ESIN (elastic stable intramedullary nailing) technique for severely displaced distal radial fracture in children. The aim of this technical report is to introduce our new method and evaluate the final results of the procedure.

PATIENT CONCERNS

We reviewed retrospectively 24 patients who underwent short double elastic nailing due to distal radial fractures between November 2012 and December 2015. Indications for surgery included closed, severely displaced, unstable metaphyseal or diametaphyseal fractures of the radius.

INTERVENTION

The fractures were stabilized by 2 prebent short elastic titanium nails inserted from the distal side of the fracture. In cases of associated ulnar fracture, a classic anterograd ESIN nailing was also performed. Patients were mobilized immediately in a removable short splint which was removed after 1 to 2 weeks. There has been no additional splinting or casting.

OUTCOMES

There were 17 males and 7 females with an average age of 9.8 years (range, 4-16 years). The right hand was involved in 16 cases and the left hand in 8 cases. The average follow-up was 17.8 months (range, 7-28 months). Of the 24 patients, 3 presented irritation of the skin, which resolved after removal of the radial nail. All the patients regained full range of motion without any complications.

LESSONS

Our technique is an effective, safe, and easily learnable procedure for unstable fractures of the distal third of the radius. It achieves good functional and radiological results, and allows early mobilization without the need of casting. Avoiding the physeal plates, we reduce the risk of iatrogenic postoperative deformity. Further prospective and biomechanical investigations are necessary to verify our experience.

Improve the Efficiency of Surgery for Femoral Shaft Fractures with A Novel Instrument: A Randomized Controlled Trial

Objective

To improve the efficacy of closed reduction and wire guiding during intramedullary nail internal fixation in femoral shaft fractures.

Methods

A novel instrument was designed and manufactured. Sixty-eight patients were enrolled from February 2011 to December 2013. The instrument designed was used during the operation in the experimental group, but not in the control group.

Results

All patients exhibited fracture union, excluding 1 patient in the experimental group and 2 in the control group who had non-union; all of whom achieved fracture union with reoperation. There were no statistically significant differences in operative blood loss or duration of hospital stay between the groups (P > 0.05). The operative time, frequency of wire drilling, and number of open reduction cases, were significantly smaller in the experimental group than in the control group (P < 0.05).

Conclusion

Femoral shaft fractures are difficult to reduce using general methods; the novel instrument showed high clinical value and proved effective and safe in assisting with closed reduction and intramedullary nail fixation for femoral shaft fractures.

Trial Registration

ChiCTR ChiCTR-ICR-15007335

KIRSCHNER WIRE VERSUS TITANIUM ELASTIC NAILS IN PEDIATRIC FEMORAL SHAFT FRACTURES

OBJECTIVE

To evaluate the effectiveness of intramedullary fixation using the Kirschner-wire (K-wire) compared to the titanium elastic nail (TEN) in pediatric femoral shaft fractures.

METHODS

A sample of 42 pediatric patients with a mean age of 6.55±2.42 years (range 4-11 years) presenting femoral shaft fractures underwent intramedullary fixation using the K-wire or TEN.

RESULTS

There was no significant difference found between groups, of which 16 (38.1%) patients were treated with K-wire and 26 (61.9%) patients were treated with TEN in terms of union duration. Moreover, none of the patients showed nonunion or a delayed union.

CONCLUSIONS

The use of adjusted K-wire instead of TEN in the intramedullary fixation of femoral shaft fractures in selected children may be an advantageous surgical option due to the lower cost, easy accessibility and no need for a second surgery for implant removal. Level of Evidence III, Retrospective Study.

Biomechanical comparison of semi-rigid pediatric locking nail versus titanium elastic nails in a femur fracture model

BACKGROUND

The treatment for length-unstable diaphyseal femur fractures among school-age children is commonly intramedullary elastic nails, with or without end caps. Another possible treatment is the semi-rigid pediatric locking nail (PLN). The purpose of this biomechanical study was to assess the stability of a length-unstable oblique midshaft fracture in a synthetic femur model stabilized with different combinations of intramedullary elastic nails and with a PLN.

METHODS

Twenty-four femur models with an intramedullary canal diameter of 10.0 mm were used. Three groups with various combinations of titanium elastic nails (TEN) with end caps and one group with a PLN were tested. An oblique midshaft fracture was created, and the models underwent compression, rotation, flexion/extension, and a varus/valgus test, with 50 and 100 % of the forces generated during walking in corresponding planes.

RESULTS

We present the results [median (range)] from 100 % loading during walking. In axial compression, the PLN was less shortened than the combination with two 4.0-mm TEN [by 4.4 (3.4-5.4) mm vs. 5.2 (4.8-6.6) mm, respectively; p = 0.030]. No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3-8.4) mm; p = 0.065]. The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm. In external rotation, the PLN rotated 12.0° (7.0-16.4°) while the TEN models displaced more than the maximum of 20.0°. No model withstood a maximal rotation of 20.0° internal rotation. In the four-point bending test, in the coronal and the sagittal plane, all combinations except the two 3.0-mm TEN in extension withstood the maximum angulation of 20.0°.

CONCLUSIONS

PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.

Pediatric femoral shaft fractures treated with titanium elastic nailing

The objective of this study was to prospectively compare intraoperative fluoroscopy time and clinical and radiological results in pediatric femoral shaft fractures treated with titanium elastic nailing (TEN) using a small-incision, blind-hand reduction vs closed reduction. From February 2008 to December 2009, sixty-eight children were enrolled in the study. Patients were divided into 2 groups: group A comprised 34 patients treated with a small-incision, blind-hand reduction technique and group B comprised 34 patients treated with a closed reduction technique. Operative time, intraoperative fluoroscopy time, fracture union time, and complications were recorded in both groups. Clinical and radiological results were assessed using the TEN scoring system. Mean operative time was 30.5±8.5 in group A and 53.0±15.0 minutes in group B, and mean fluoroscopy time was 28.4±18.5 seconds in group A and 65.0±28.5 seconds in group B. Operative time and fluoroscopy time were significantly longer in group B (P<.001). According to the TEN scoring system, the results were excellent in 31 patients and good in 3 patients in group A and excellent in 29 patients and good in 5 patients in group B. There was no significant difference between the 2 groups in terms of clinical and radiological results. There was also no significant difference in terms of fracture healing time, weight-bearing time, and complications. The small-incision, blind-hand reduction technique provided similar clinical results as closed reduction. This technique could be an alternative to closed reduction because it significantly reduced intraoperative radiation exposure and operative time.

Elastic nailing for pediatric subtrochanteric and supracondylar femur fractures

BACKGROUND

Subtrochanteric and supracondylar femur fractures are difficult injuries to treat in children. Although elastic stable intramedullary nails are commonly used for pediatric femur shaft fractures, there is little information on their effectiveness for managing pediatric subtrochanteric and supracondylar femur fractures.

QUESTIONS/PURPOSES

We (1) evaluated radiographic union rates and fracture alignment after elastic nailing of pediatric subtrochanteric and supracondylar femur fractures, (2) identified complications, and (3) determined risk factors for complications.

METHODS

Between 2005 and 2011, 36 subtrochanteric fractures and eight supracondylar femur fractures were treated with elastic stable intramedullary nails and had complete followup until clinical and radiographic union. Elastic nailing was used for subtrochanteric fractures in children 5 to 12 years of age or after failed spica cast treatment in younger children and for displaced supracondylar fractures in children older than 5 years. Fracture alignment and union were measured on radiographs, and complications were identified from review of patient charts. Patients with and without complications were compared using nonparametric tests to identify risk factors.

RESULTS

All fractures healed; 23 of 33 (70%) subtrochanteric femur fractures and five of seven (71%) supracondylar femur fractures healed with anterior angulation of about 5°. For subtrochanteric fractures, complications included repositioning/removal of nails before radiographic union (n = 4), malunion (n = 2), fracture (n = 1), irritation (n = 1) at nail insertion site, and limb length discrepancy (n = 1); despite these complications, there were 22 (61%) excellent, 12 (33%) satisfactory, and only two (6%) poor outcomes. For supracondylar fractures, complications included infection after nail removal (n = 1) and nail site irritation (n = 2); there were three (38%) excellent, five (62%) satisfactory, and no poor outcomes. Complications were more likely after subtrochanteric fracture during motor vehicle accident (p = 0.045).

CONCLUSIONS

Although complication rates are high with elastic nailing for pediatric subtrochanteric (22%) and supracondylar (38%) femur fractures, elastic nailing represents an important option for difficult-to-manage femur fractures.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Modification of elastic stable intramedullary nailing with a 3rd nail in a femoral spiral fracture model - results of biomechanical testing and a prospective clinical study

Background

Elastic stable intramedullary nailing (ESIN) is the standard treatment for displaced diaphyseal femoral fractures in children. However, high complication rates (10-50%) are reported in complex fractures. This biomechanical study compares the stiffness with a 3rd nail implanted to that in the classical 2C-shaped configuration and presents the application into clinical practice.

Methods

For each of the 3 configurations of ESIN-osteosynthesis with titanium nails eight composite femoral grafts (Sawbones®) with an identical spiral fracture were used: 2C configuration (2C-shaped nails, 2 × 3.5 mm), 3CM configuration (3rd nail from medial) and 3CL configuration (3rd nail from lateral). Each group underwent biomechanical testing in 4-point bending, internal/external rotation and axial compression.

Results

2C and 3CM configurations showed no significant differences in this spiroid type fracture model. 3CL had a significantly higher stiffness during anterior-posterior bending, internal rotation and 9° compression than 2C, and was stiffer in the lateral-medial direction than 3CM. The 3CL was less stable during p-a bending and external rotation than both the others. As biomechanical testing showed a higher stability for the 3CL configuration in two (a-p corresponding to recurvation and 9° compression to shortening) of three directions associated with the most important clinical problems, we added a 3rd nail in ESIN-osteosynthesis for femoral fractures. 11 boys and 6 girls (2.5-15 years) were treated with modified ESIN of whom 12 were ‘3CL’; due to the individual character of the fractures 4 patients were treated with ‘3CM’ (third nail from medial) and as an exception 1 adolescent with 4 nails and one boy with plate osteosynthesis. No additional stabilizations or re-operations were necessary. All patients achieved full points in the Harris-Score at follow-up; no limb length discrepancy occurred.

Conclusion

The 3CL configuration provided a significantly higher stiffness than 2C and 3CM configurations in this biomechanical model. These results were successfully transmitted into clinical practice. All children, treated by 3CL or 3CM according to the individual character of each fracture, needed no additional stabilization and had no Re-Do operations. As a consequence, at our hospital all children with femoral diaphyseal fractures with open physis are treated with this modified ESIN-technique.

Distal femoral valgus deformity following plate fixation of pediatric femoral shaft fractures

BACKGROUND

This study investigated the frequency and potential risk factors associated with the development of distal femoral valgus deformity following plate fixation of diaphyseal femoral fractures in children.

METHODS

Records of eighty-five skeletally immature patients who underwent plate fixation of a diaphyseal femoral fracture at a tertiary-care pediatric center from January 2003 to December 2010 were reviewed. Demographic data and clinical information were analyzed. Radiographic measurement of the distance from the distal plate edge to the distal femoral physis and of the anatomic lateral distal femoral angle was performed. Development of distal femoral valgus deformity was defined as a change in the anatomic lateral distal femoral angle of ≥5° in the valgus direction. Logistic regression analysis and contingency tables were used to relate the development of distal femoral valgus deformity with retention of hardware, patient age, fracture site, plate-to-physis distance, and the location of a bend in the plate at fixation.

RESULTS

Midshaft fractures (45%) were more common than proximal or distal diaphyseal fractures. Intraoperatively, the plate was bent proximally or distally, or both, in 80% of the patients. Distal femoral valgus deformity of ≥5° was seen in ten patients, eight of whom had distal diaphyseal fractures. Three of the ten patients developed symptoms as a result of the distal femoral valgus deformity that required at least one unplanned additional surgical procedure. On the basis of the statistical analysis, patients with a plate-to-physis distance of ≤20 mm (relative risk= 12.77, p = 0.005) and a distal fracture (relative risk = 11.0, p < 0.001) were at a significantly higher risk of developing distal femoral valgus deformity. Although not clearly an independent factor, a distal bend was also found to be associated with distal femoral valgus deformity (p = 0.004) but was not predictive of the pathology.

CONCLUSIONS

Distal femoral valgus deformity occurred in 30% of patients with distal diaphyseal fractures and in 12% overall. We advocate long-term monitoring of patients with femoral plate fixation, particularly those in whom the plate is placed ≤20 mm from the distal femoral physis.

Biomechanical performance of flexible intramedullary nails with end caps tested in distal segmental defects of pediatric femur models

BACKGROUND

Unstable distal femoral fractures in children are challenging lesions with restricted surgical options for adequate stabilization. Elastic nails have become popular for treating femoral shaft fractures, yet they are still challenging for using in distal fractures. The aim of this study was to test whether end caps (CAP) inserted into the nail extremity improved the mechanical stabilization of a segmental defect at the distal femoral metaphyseal-diaphyseal junction created in an artificial pediatric bone model.

METHODS

Two 3.5-mm titanium elastic nails (TEN) were introduced intramedullary into pediatric femur models, and a 7.0-mm-thick segmental defect was created at the distal diaphyseal-metaphyseal junction. Nondestructive 4-point bending, axial-bending, and torsion tests were conducted. After this, the end caps were inserted into the external tips of the nails and then screwed into the bone cortex. The mechanical tests were repeated. Stiffness, displacement, and torque were analyzed using the Wilcoxon nonparametric test for paired samples.

RESULTS

In the combined axial-bending tests, the TEN+CAP combination was 8.75% stiffer than nails alone (P<0.01); in torsion tests, the TEN+CAP was 14% stiffer than nails alone (P<0.01). In contrast, the 4-point bending test did not show differences between the methods (P=0.91, stiffness; P=0.51, displacement). Thus, the end caps contributed to an increase in the construct stability for torsion and axial-bending forces but not for 4-point bending forces.

CONCLUSIONS

These findings indicate that end caps fitted to elastic nails may contribute to the stabilization of fractures that our model mimics (small distal fragment, bone comminution, and distal bone fragment loss).

CLINICAL RELEVANCE

Type II [therapeutic study: lesser-quality randomized controlled trial (eg, <80% follow-up, no blinding, or improper randomization)].

Biomechanical analysis of pin placement for pediatric supracondylar humerus fractures: does starting point, pin size, and number matter?

BACKGROUND

Several studies have examined the biomechanical stability of smooth wire fixation constructs used to stabilize pediatric supracondylar humerus fractures. An analysis of varying pin size, number, and lateral starting points has not been performed previously.

METHODS

Twenty synthetic humeri were sectioned in the midolecranon fossa to simulate a supracondylar humerus fracture. Specimens were all anatomically reduced and pinned with a lateral-entry configuration. There were 2 main groups based on specific lateral-entry starting point (direct lateral vs. capitellar). Within these groups pin size (1.6 vs. 2.0 mm) and number of pins (2 vs. 3) were varied and the specimens biomechanically tested. Each construct was tested in extension, varus, valgus, internal, and external rotation. Data for fragment stiffness (N/mm or N mm/degree) were analyzed with a multivariate analysis of variance and Bonferroni post hoc analysis (P<0.05).

RESULTS

The capitellar starting point provided for increased stiffness in internal and external rotation compared with a direct lateral starting point (P<0.05). Two 2.0-mm pins were statistically superior to two 1.6-mm pins in internal and external rotation. There was no significant difference found comparing two versus three 1.6-mm pins.

CONCLUSIONS

The best torsional resistances were found in the capitellar starting group along with increased pin diameter. The capitellar starting point enables the surgeon to engage sufficient bone of the distal fragment and maximizes pin separation at the fracture site. In our anatomically reduced fracture model, the addition of a third pin provided no biomechanical advantage.

CLINICAL RELEVANCE

Consider a capitellar starting point for the more distally placed pin in supracondylar humerus fractures, and if the patient's size allows, a larger pin construct will provide improved stiffness with regard to rotational stresses.

Treatment of femoral shaft fracture with an interlocking humeral nail in older children and adolescents

PURPOSE

Rigid interlocking nailing for femoral shaft fracture is ideal for use in adolescents in terms of stability of the fracture and convenience for the patient. However, numerous authors have reported that rigid interlocking nailing has some limitations in this age group due to the risk of complications. We evaluated the results of intramedullary nailing for femoral shaft fractures with an interlocking humeral nail in older children and adolescents.

MATERIALS AND METHODS

We retrospectively reviewed records of patients treated with an interlocking humeral nail. Radiographs were examined for proximal femoral change and evidence of osteonecrosis. Outcomes were assessed by major or minor complications that occurred after operative treatment.

RESULTS

Twenty-four femoral shaft fractures in 23 patients were enrolled. The mean age at the time of operation was 12 years and 8 months and the mean follow- up period was 21 months. Bony union was achieved in all patients without any complications related to the procedure such as infection, nonunion, malalignment and limb length discrepancy. All fractures were clinically and radiographically united within an average eight weeks. No patients developed avascular necrosis of the femoral head and coxa valga.

CONCLUSION

Intramedullary nailing through the greater trochanter using a rigid interlocking humeral nail is effective and safe for the treatment of femoral shaft fractures in older children and adolescents.

Does the extent of prebending affect the stability of femoral shaft fractures stabilized by titanium elastic nails? A biomechanical investigation on an adolescent femur model

BACKGROUND

Elastic stable intramedullary nailing (ESIN) is a common procedure for stabilization of femoral shaft fractures in childhood. Prebending of the nail is generally recommended to achieve optimal nail tension at the fracture site. To our knowledge there are no published data on the effects of prebending on stability. The purpose of this biomechanical study was to compare the effects of different degrees of prebending on the stability of transverse femoral fractures after ESIN using a bone model.

METHODS

Standardized transverse midshaft fractures were created in 20 synthetic, biomechanically validated adolescent bones (4th Generation Composite Femur--Sawbones Europe AB, Sweden) that were stabilized with 2 titanium nails (TEN) each (4 mm diameter, Synthes) and inserted in standardized retrograde technique. The 4 test series addressed nail prebending at 0 degree, 30 degrees, 45 degrees, and 60 degrees. The models were tested biomechanically in 4-point bending in the coronal and sagittal planes, relative stiffness was determined and analyzed statistically. The level of significance was set at P < 0.05.

RESULTS

Comparison of the individual groups showed no significant differences in stiffness for different degrees of prebending in the coronal plane. Significantly reduced stiffness was found in the sagittal plane for the group with 60-degree prebending compared with the 0-degree, 30-degree, and 45-degree prebending groups. Intragroup comparison in the coronal and sagittal planes yielded a significantly reduced stiffness in the sagittal plane compared with the coronal plane in the group with 60-degree prebending. The 45-degree prebending group showed a similar tendency and in the 0-degree and 30-degree prebending groups there were no significant differences.

CONCLUSIONS

On a synthetic bone model, prebending of TEN was found to affect the stability of transverse fractures of the femoral shaft, whereby indiscriminate prebending will reduce stability in the sagittal plane.Despite limited extrapolation of the findings to the in vivo situation, it can be stated that prebending of TEN by 0 to 30 degrees offers the greatest stability in the coronal and sagittal planes for transverse fractures of the femoral shaft.

Intramedullary nailing of pediatric femoral shaft fracture

Intramedullary nail fixation of pediatric long bone fracture, particularly femoral shaft fracture, has revolutionized the care and outcome of these complex injuries. Nailing is associated with a high rate of union and a low rate of complications. Improved understanding of proximal femoral vascularity has led to changes in nail insertion methodology. Multiple fixation devices are available; selection is based on fracture type, patient age, skeletal maturity, and body mass index. A thorough knowledge of anatomy and biomechanics is required to achieve optimal results without negatively affecting skeletal development.

Biomechanical analysis of supracondylar humerus fracture pinning for slightly malreduced fractures

BACKGROUND

The most common position of malreduced type III supracondylar humerus (SCH) fractures is internal rotation and medial collapse of the distal fragment. The purpose of this study was to determine the effect of SCH fracture rotational deformity on stability with various pin configurations. Specifically, is the biomechanical stability lost when an SCH fracture is pinned in slight malreduction (compared with anatomical pinning) improved by adding a third pin?

METHODS

Sixty-four synthetic humeri were sectioned in the mid-olecranon fossa to simulate an SCH fracture. Specimens were randomized to an anatomically reduced group or a group with 20 degrees of distal fragment internal rotation (n = 32 per group). Each was randomized to one of 4 pin configurations: 2 laterally divergent pins, 2 crossed pins, 3 laterally divergent pins, or 2 lateral with 1 medial pin (n = 8 per group). All fractures were stabilized with 1.6 mm (0.062 in) Kirschner wires. Models were tested in extension, varus, and valgus for 10 cycles between 5 N and 50 N. Internal and external rotations were tested between +/-1 Nm. Data for fragment stiffness (newtons per millimeter or newton millimeters per degree) were analyzed with a 2-way analysis of variance (p < 0.05).

RESULTS

Internally rotated fractures were significantly less stable than the anatomically reduced group for external rotation, internal rotation, and varus loading regardless of pin configuration. Within the malreduced group, 3-pin configurations were more stable than 2-pin configurations in internal rotation, varus, and extension loading. Two lateral divergent pins were similar to 2 crossed pins, except in extension, where 2 lateral pins had greater stiffness.

CONCLUSIONS

Construct stiffness for malreduced specimens after pinning was less than those pinned with an anatomical reduction when loaded in varus, internal rotation, and external rotation. For simulated fractures with residual internal rotation, the addition of a third Kirschner wire compared with an anatomically reduced 2-crossed-pin configuration resulted in increased stiffness of the model for all loading directions.

CLINICAL RELEVANCE

Consider a 3-pin pattern, either 3 laterally divergent pins or 2 lateral pins and 1 medial pin, for SCH fractures when a less than complete anatomical reduction is obtained.

Locking plate fixation for pediatric femur fractures

BACKGROUND

The use of locking plates for pediatric femur fractures has not been studied. Locking plate applications for fractures associated with comminution, osteopenia, or minimal bone available for purchase have been well studied in the adult trauma population.

METHODS

We conducted a retrospective review of children at our institution treated with a locking plate for a femur fracture. We identified 32 patients treated at an average age of 11 years (6-15 years of age). Locking plates were chosen for comminution in 13 patients, nonmalignant pathologic fracture in 9 patients, fracture location in 7 patients, and osteopenia in 3 patients. All patients were treated with a locking plate and followed up until definitive radiologic union.

RESULTS

There were no intraoperative complications related to this technology. All patients were healed with near-anatomic alignment with the exception of 1 patient who had valgus malalignment of 12 degrees, which was of no clinical concern and required no intervention. Seven patients had the plates removed with no noted complications.

CONCLUSIONS

Locking plates are a safe and effective treatment for children and adolescents with femur fractures that may not be amenable to other current means of stabilization.

Biomechanical evaluation of retrograde intramedullary stabilization for femoral fractures: the effect of fracture level

BACKGROUND

Retrograde stabilization of mid-diaphysis adolescent femur fractures has shown excellent biomechanical stability. However, it is unclear whether adequate stability is maintained for distal femur fractures using the retrograde approach compared with the clinically recommended antegrade approach. The purpose of this study was to evaluate the biomechanical stability of retrograde and antegrade nailing for mid-diaphyseal and distal diaphysis femoral fractures.

METHODS

Twenty adolescent-sized synthetic femurs were randomly assigned to fracture location and surgical approach groups. Comminuted fractures were simulated at the mid-diaphysial level and 4 cm proximal to the distal physis. The retrograde approach used 2 c-shaped 3.5-mm titanium nails. The antegrade used c and s 3.5-mm nail configurations. Both techniques achieved maximum nail divergence at the level of the fracture. Biomechanical testing was conducted to determine differences in torsional range of motion (degrees)and failure load (N) at 5 mm. These data were analyzed with a 2-way analysis of variance (p < 0.05).

RESULTS

In torsion, there were no differences related to surgical approach or fracture level. For axial compression to 5 mm, the antegrade approach required significantly greater force to achieve 5 mm of compression compared with the retrograde approach. The mid-diaphyseal fracture required significantly greater force to achieve 5 mm of compression compared with the distal diaphysis group.

CONCLUSIONS

For maximum stabilization of a distal femur fracture, c- and s-shaped nails placed in the antegrade position is suggested.

CLINICAL RELEVANCE

Surgical decision making regarding the use of either the antegrade or retrograde approach will be influenced by both the stability provided (antegrade) and the ease of insertion (retrograde).

A computational evaluation of the effect of intramedullary nail material properties on the stabilization of simulated femoral shaft fractures

Titanium flexible intramedullary nails have become far more prevalent for stabilization of pediatric femur fractures in recent years. While steel may be expected to have superior fracture stability due to its higher elastic modulus; titanium alloy has experimentally demonstrated improved biomechanical stability, as measured by gap closure and nail slippage. The purpose of this study was to verify these observations computationally, and thus, explain why titanium alloy may be better suited for surgical fixation of fractured femurs. A finite element model of a femur with complete mid-diaphyseal fracture and having two 3.5 mm nails in a retrograde "C" pattern was created. Static analyses were run in which the nail material properties were titanium alloy or stainless steel, respectively. Gap closure for the stainless steel nails was 1.03 mm; while the titanium alloy nails had 0.69 mm of closure. Titanium alloy nails slipped slightly less at each loading increment than stainless steel nails. The titanium alloy nails distributed stress more evenly along the nail axis, resulting in lower peak magnitudes. These results agree with previously published clinical and biomechanical studies that reported increased gap closure and nail slippage with stainless steel nails. The increased deformation of the titanium alloy nail likely increases the contact area with the intramedullary canal wall, thus, increasing stability. Additionally, stainless steel nails had higher curve apex von Mises stresses, potentially inducing a stress-shielding effect which could hamper remodeling and consequently increase risk of re-fracture.