Expandable nail system for osteoporotic humeral shaft fractures: preliminary results

Mechanical comparison of standard interlocking, clawed, and expandable wedge locked nail fixations: An experimental and numerical study

INTRODUCTION

Intramedullary nailing has been used as a standard in the treatment of the long bone fractures with its clinical and mechanical advantages. However, using distal locking screws has been associated with longer operative times, higher radiation exposure rates, and complications like breakages of distal screw or nail at the screw hole level. Therefore, attempts to eliminate distal locking screws has been always present for intramedullary nail fixation. With a similar purpose, the present study has been carried out to compare mechanical behaviors of intramedullary nail fixations with different distal locking elements.

MATERIALS AND METHODS

In this study, mechanical behaviors of standard interlocking and clawed nail fixations were compared experimentally in the first part. Six fourth generation Sawbones femurs, which have a simulated subtrochanteric fracture, were divided equally and were fixed with standard interlocking and clawed nails. During axial compression tests, experimental strain measurements were taken from all fixations. After validation of numerical models with using experimental strains and stiffnesses, mechanical behaviors of standard interlocking, clawed, and wedge locked nail fixations were compared numerically under axial compression loads. In numerical comparison, the stress-strain distributions were evaluated.

RESULTS

Experimental results showed that although that there was no significant difference in stiffnesses, standard nail fixation bore two times higher loads than clawed nail fixations. Under loading, decrease in the distance between fracture surfaces was approximately seven times higher in the clawed nail fixation when compared to standard nail fixations. Numerical results showed that wedge locked nail fixation provided equivalent mechanical behavior to standard interlocking nail.

DISCUSSION

In experiments of clawed nail fixation, the high decrease in the distance between fracture surfaces was evidence of the slippage of nail in the medullary canal. For a safe fixation, claws should be deployed when they are completely in contact with the cortical bone, they should be stuck into the bone in a fair amount, and the deployment in the distal third of the femur should be avoided. According to experimentally validated numerical analyses, wedge locked nail fixation may be an alternative for standard interlocking nail fixation if experimental studies support the present results.

Development of an additively-manufactured functionally-graded expandable implant via the application of the adaptive response surface method: feasibility study on intramedullary humerus nail

The paper introduces the concept of the rational design of a deployable humeral intramedullary nail plug based on a honeycomb structure used for the surgical treatment of humeral shaft fractures. The concept serves for to restore the axial alignment of bone fragments and to maintain stability via bone-nail friction and locking screws. The design nail plug was gained by optimisation process the Latin Hypercube Sampling Design algorithm and Multi-Objective Genetic Algorithm. It was shown that we can use statistical shape function combined by 3 D printing for designing of a new rationally designed implants.

Comparison of Expandable and Locked Intramedullary Nailing for Humeral Shaft Fractures

Introduction In this study, we clinically and radiologically investigated whether the application of expandable nails for surgical treatment of humeral shaft fractures has an advantage over locked intramedullary nails. Methods Patients treated with intramedullary fixation due to humeral shaft fractures in our clinic were investigated retrospectively. Patients with fractures of type 12A and 12B according to the AO classification in the middle 1/3 shaft region of the humerus were divided into two groups as those receiving fixation with expandable nails and with locked intramedullary nails. The union rate, union time, Q-DASH scores, duration of surgery, and complication rates were statistically compared between the two groups. Results The study included 38 patients with clinical follow-up from among 47 patients; 20 patients received fixation with locked intramedullary nails and 18 with expandable nails. The mean age of the patients was 56.92 (19-91) years and 53% (n=20) were men while 47% (n=18) were women. During statistical evaluation, a statistically significant difference was found between the groups for union (100% and 72.2%) and complication rates (6% and 13%). More union and lower complication rates were found in patients treated with locked intramedullary nails. In comparing the mean of surgical times (71.1 and 30.2 min), expandable nails had a shorter surgical time. However, there was no statistically significant difference between the union time and Q-DASH scores between the two groups. Conclusion Locked intramedullary nails are a better fixation method than expandable nails due to the low complication rate and high rate of union. However, due to shorter surgery time, expandable nailing is an alternative method in limited cases.

Review of expandable dental implants

In the last few years the dental implants market has grown both in developed and developing countries, and is associated with high aesthetic expectations and well-being. Although the success rate of commercial implants is high, some problems associated with a lack of initial stability, marginal bony resorption, and periodontal health, remain, especially with immediate placement and loading. The market offers different designs of dental implants, but cylindrical and tapered devices that are fixed to the bone via an external thread are dominant. One lesser-known but potentially useful design is the expandable dental implant (EDI). This paper presents a review of expandable dental implants that encompasses a survey of the literature, published patents, and available commercial devices. We found 15 articles: prospective human trials (n=4), human case reports (n=3), published independent discussions of other articles (n=2), three big animal trials (n=3), and in silico studies (n=3). A total of 73 published patents were found and two expandable dental implants are commercially available to date. We propose a classification system that differentiates between the expansion mechanism and the origin of the expanding action. Some expandable designs have been shown to provide good primary stability, but evidence to date is limited. We encourage future clinical and biomechanical studies to clarify and optimise the potential benefits of these implants.

Plate fixation versus intramedullary nailing of proximal humerus fractures: an ACS NSQIP-based comparative analysis over 8 years

PURPOSE

The primary goal of this study was to compare the utilization of plate versus intramedullary nail (IMN) in the treatment of humerus fractures. Secondarily, we sought to examine whether any differences in demographics and clinical course of patients who receive a nail versus plate affect the procedure selection process.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was queried for patients surgically treated for a humeral shaft fracture from the years 2007-2015, using current procedural terminology (CPT) code. Patients with overlapping procedures, nonunion, polytrauma, and malignancy were excluded. The Charlson Comorbidity Index (CCI) was calculated to compare preoperative comorbidities. A two-sample Wilcoxon rank-sum (Mann-Whitney U) test was used to compare numerical values, whereas the Fisher exact and Chi-squared analyses were performed to compare categorical variables. A p value < 0.05 was considered significant. Preoperative variables with a p value < 0.05 and a clinical prevalence > 1%, indicating statistical and clinical significance, were included in a logistic regression for multivariate analysis to identify any independent predictors for procedure selection (IMN versus PF) based on preoperative patient characteristics.

RESULTS

During the study period plate fixation increased from 7 cases per year to 272 cases per year, while IMN increased from 8 cases per year to 80 cases per year. IMNs were mostly in older patients (63.85 vs 56.19 years, p < 0.001), and patients with a higher Charlson Comorbidity Index (CCI) (4.64 vs 2.79, p < 0.001). IMN was associated with shorter operation times (104 min vs 128 min, p < 0.001) and longer lengths of hospital stay (3.43d vs 2.78d, p < 0.001). No significant differences in overall complication rates were seen between patients who received IMN versus PF. However, the postoperative mortality rate was higher in patients who received IMN compared to PF (2.19% vs 0.40%, p < 0.01). Based on the regression analysis, patient age was the only independent patient factor demonstrated to predict the utilization of IMN over PF in older patients with humeral shaft fractures p = 0.043).

CONCLUSION

According to this NSQIP-based analysis, the rate of PF and IMN utilization increased in the treatment of humeral shaft fractures over a period of 8 years, but PF was performed at an overall a higher rate than IMN. Intramedullary nailing was preferred over PF in older patients with more comorbidities. The last possibly contributed to the higher 30-day mortality rate observed in patients who received IMN compared to PF.

LEVEL OF EVIDENCE III

Retrospective comparative study.

The inflatable intramedullary nail for humeral shaft fractures

BACKGROUND

We assessed the results of humeral shaft fracture fixation using the inflatable intramedullary nail using radiological and clinical findings.

METHODS

From 2012 to 2015, we treated 14 patients with humeral shaft fractures using inflatable intramedullary nail after closed reduction.

RESULTS

The mean follow-up time was 14.1 months. The mean time to bone union was 4.5 months. None of the patients had major perioperative mechanical complications or postoperative complications, except for the occurrence of fixation loss and non-union in one patient.

CONCLUSION

Inflatable intramedullary nails seem to be applicable, safe and effective for humeral AO/OTA type A midshaft fractures.

Femoral midshaft fractures: expandable versus locked nailing

Femoral midshaft fracture is one of the most common clinical injuries and is often caused by high-energy traffic accidents. Intramedullary nailings, plates, and external fixators are all used as treatment alternatives for a variety of patients depending on fracture location, displacement, comminution, soft tissue condition, and local tradition. Locked intramedullary nailing is currently the preferred treatment method for most diaphyseal fractures and has good clinical results. The goal of this study was to compare expandable and locked intramedullary nailing for the treatment of AO type 32A and 32B1 femoral midshaft fractures. The authors performed a retrospective analysis of 46 patients (33 men and 13 women; mean age, 32.3 years; range, 22-52 years) with femoral midshaft fractures who were divided into 2 groups-one treated with an expandable intramedullary nailing method and the other with a conventional locked intramedullary nailing. The 2 groups were compared with respect to operation time, fluoroscopic time, amount of estimated blood loss, hospitalization time, healing time, and complications. Patients were followed for at least 1 year. The results of this study showed that all of the patients achieved bone union within 12 to 24 months. Expandable nailing performed better than locked nailing in operation time, fluoroscopic time, amount of estimated blood loss, and healing time (P<.001). There was no difference in hospitalization time and no visible shortening or severe complications were observed in either group. Based on the results of this study, the expandable intramedullary nailing is an easy and effective treatment for AO type 32A and 32B1 diaphyseal femoral fractures.

Diaphyseal humeral fractures and intramedullary nailing: Can we improve outcomes?

While intramedullary nailing has been established as the treatment of choice for diaphyseal fractures of the femur and tibia, its role in the management of diaphyseal humeral fractures remains controversial. The reasons include not only the complicated anatomy and unique biomechanical characteristics of the arm but also the fact that surgical technique and nail designs devised for the treatment of femoral and tibial fractures are being transposed to the humerus. As a result there is no consensus on many aspects of the humeral nailing procedure, e.g., the basic nail design, nail selection criteria, timing of the procedure, and the fundamental principles of the surgical technique (e.g., antegrade/retrograde, reamed/unreamed, and static/dynamic). These issues will be analyzed and discussed in the present article. Proposals aiming to improve outcomes include the categorization of humeral nails in two distinct groups: "fixed" and "bio", avoidance of reaming for the antegrade technique and utilization of "semi-reaming" for the retrograde technique, guidelines for reducing complications, setting the best "timing" for nailing and criteria for selecting the most appropriate surgical technique (antegrade or retrograde). Finally, suggestions are made on proper planning and conducting clinical and biomechanical studies regarding the use of intramedullary nailing in the management of humeral shaft fractures.

Clinical and radiological midterm results from using the Fixion expandable intramedullary nail in transverse and short oblique fractures of femur and tibia

Background

A locked nail is the principal method used to eliminate rotatory components in femoral and tibial fractures. Nevertheless, weight bearing is not directed onto the fracture site, slowing down the healing process; another possibility is to use a large-diameter nail and ream the canal to obtain as much adherence as possible and increase the grip, but this can cause a number of complications. The expandable nail is a new option that in theory should remove some problems with previous techniques.

Materials and methods

This was a retrospective nonrandomized study encompassing 21 femoral fractures and 27 tibial fractures in 45 patients. They were classified according to the AO classification. Clinical and radiological checks were done at one, three, and six months and at one year from the surgery in order to check for signs of clinical and radiological healing. A good alignment was considered to be the presence of a deformity of less than 5° in the sagittal and lateral planes and the absence of rotatory clinically evident problems. This protocol was adhered to up to six months after surgery by all of the patients, while only 62.2% performed the last control. The mean follow-up was 15 months. A second group of 48 consecutive fractures (24 femural and 24 tibial) treated with locked nail was created to compare surgical times.

Results

Appropriate alignment was observed in all cases; the healing process appeared slower: radiological healing occurred in most cases at six months. The following complications were reported: a case of intraoperative fracture widening with no effect on the treatment; a case of a lesion of the tip of the nail with pneumatic system rupture that necessitated nail substitution; two cases of retarded consolidation at six months, with both tibial fractures treated successfully by intralesion platelet gel; a case of incarcerated nail on 17 removals, resolved by shearing. We had no cases of clinically evident compartment syndrome or pulmonary embolism.

Conclusions

The expandable Fixion nail presents significant advantages in the treatment of transverse and short oblique fractures of femur and tibia because it is easy to use, involves minimal X-ray exposure and can control rotations. Nevertheless, it high cost limits its use. We consider it as an alternative to locked nail.

Expandable nailing system for tibial shaft fractures

OBJECTIVE

To evaluate and present our current clinical experience in the treatment of closed and open tibial shaft fractures using the expandable intramedullary nailing system.

DESIGN

Prospective study.

SETTING

One level-1 trauma centre.

PARTICIPANTS

Twenty-six patients with acute tibial shaft fractures with at least 10 cm of intact cortex on both sides of the fracture.

INTERVENTION

Internal fixation using the Fixion expandable intramedullary nail (Disc-O-Tech Medical Technologies Ltd., Herzliya, Israel).

MAIN OUTCOME MEASUREMENTS

Operative and fluoroscopy time, healing time and perioperative complications were recorded.

RESULTS

Twenty-six tibial fractures were treated (OTA classification: 3 type A1, 8 A2, 8 A3, 3 B1, 3 B2, and 1 B3), six of which were open. All fractures healed by week 18.5 with an mean of 12.8+/-3.8 weeks. The operating time ranged from 20 to 50 min with an mean of 40+/-12.17 min. The fluoroscopy time ranged from 6 to 22s with a mean of 10+/-5s. In one case the nail failed to expand, as detected by X-ray control, and had to be exchanged intraoperatively. Two patients reported anterior knee pain during the follow up, but did not wish any further treatment. In a low demanding patient rotational malalignment was noted and no further action needed.

CONCLUSION

According to the results of this study, the use of the Fixion nailing system, where indicated, is associated with minimal complications and very good functional outcomes in fractures OTA types A and B. The advantages of the expandable nail include the decrease in the operating and fluoroscopy time and the simplicity of its application.

Biomechanical comparison of expandable and locked intramedullary femoral nails

OBJECTIVES

The expandable intramedullary (IM) nail does not require locking and fluoroscopy use is minimized. However, the lack of cross-locking screws may adversely affect the fixation's rotational stability. The purpose of our study was to compare the rotational stability afforded by an expandable nail with that of a standard locked nail.

METHODS

In a cadaver model of a diaphyseal femoral fracture (OTA type 32-A3), we compared first-generation expandable IM nails with standard locked IM nails in osteoporotic and nonosteoporotic femora (10 pairs each) and second-generation expandable nails with standard locked IM nails only in nonosteoporotic femora (10 pairs). To simulate torsional loads during walking, we applied an external rotation moment of -1 to 10 Nm at 1 Hz to each construct for 5000 cycles. Failure was defined as 15 degrees of rotation at the fracture site. We used McNemar's test to check for significant (P < 0.05) differences in failure between groups.

RESULTS

Of the first-generation expandable nails, 90% failed (9/10 in osteoporotic and 9/10 in nonosteoporotic femora) within the first 1000 cycles. Of the respective locked nails, significantly fewer failed in nonosteoporotic femora than in osteoporotic femora (0/10 and 3/10, respectively). Of the second-generation nails, 8/10 failed within 100 cycles of testing. Of the comparative locked nails, none failed at 5000 cycles.

CONCLUSIONS

We concluded that the expandable IM femoral nail, when tested in purely axial rotation, has poor rotational stability compared with the standard locked IM femoral nail.

Extreme complications of Fixion nail in treatment of long bone fractures

The authors present their experience related to extreme complications in treatment of diaphyseal fractures of the long bones with application of the Fixion expansion intramedullary nail in a total of 48 surgeries. We have encountered six (12.5%) extreme complications in the management of fractures of 3 humeral, 2 tibial, and 1 femoral bones during its application procedure and postoperative follow-up. Of six cases, two with humeral and tibial fractures developed nonunion and rotational instability because of failure of inflation of the Fixion nail. One of the Fixion nail in humerus was broken spontaneously, and one of the Fixion nail deflated at the follow-up and pseudoarthrosis developed in this patient. In a patient with osteogenesis imperfecta, during the inflation of the nail for the treatment of femur fracture, a new longitudinal fracture occurred and conventional non-locking intramedullary nail was inserted. In a patient with a tibia fracture that was treated with the Fixion nail, new fracture occurred due to its bending after weight bearing in the postoperative period. The Fixion nail application is a new technique for the intramedullar fixation of long bones. It is considered as an effective method for the selective fracture types of long bones. Application may need special training. Since the Fixion has not got rotational stability and rigidity as conventional nailing systems, bending and breaking of the nail may occur during postoperative period in patients with over obesity and hyperactivity. In patients with osteogenesis imperfecta, it may not be the first choice as a nailing system.

Humeral fractures in the elderly: treatment with a reamed intramedullary locking nail

In the elderly person, comorbidities combined with lower functional demands tend to indicate non-operative treatment; however, fast functional recovery is mandatory to prevent loss of independency and social ability. This retrospective follow-up study included 40 people with a mean age of 75 (range 60-87) years. They had all received treatment with a reamed intramedullary nail for humeral fracture; 21 were operated after a mean of 6 (range 0-16) days, and 19 after a mean of 28 (range 9-63) days after a primary decision for non-operative treatment. In all, 5 cases (12.5%) were lost to follow-up. The primary healing rate was 94% (33/35) after a mean of 17 (range 6-61) weeks; 14% (5/35) needed re-operation, in 2 cases because of healing problems. Functional results could be assessed in 18 cases: the median Neer score was 90 (range 45-97) points and the median Morrey score 98 (range 74-100) points. The relative functional scores were 94 (range 89-101) and 100 (range 97-100) points, respectively. All functional scores were independent of introduction site and time to treatment. On the basis of these results we conclude that treatment of humeral fractures in the elderly with an intramedullary nail leads to good healing and functional results, and an acceptable re-operation rate.

Biomechanical Evaluation of an Expandable Nail for the Fixation of Midshaft Fractures

BACKGROUND

The objective of this study was to compare the torsional stability of diaphyseal long bone fractures fixed with either a Fixion nail (DiscOTech, Monroe Township, NJ) or a standard locked Zimmer M/DN locked nail (Zimmer, Warsaw, IN).

METHODS

Two fracture models were used to evaluate the bone-implant constructs. A transverse osteotomy was created in all tibiae, and a spiral fracture was created in all humeri. Paired specimens were randomly assigned to receive either a Fixion or Zimmer M/DN locked nail. Each implanted construct was cyclically loaded in torsion, and construct stiffness for each fracture type and each bone computed from the resulting load-displacement curves.

RESULTS

Performance of the Fixon nail in the tibial transverse model was variable: 2 of 10 implanted constructs failed during testing, and average construct stiffness was significantly greater for the Zimmer nail. No significant difference was found between the stiffness of the Zimmer M/DN and Fixion implanted humeral constructs either with or without the interlock.

CONCLUSIONS

Fracture type significantly affected the performance of the Fixion nail. Our results suggest that the Fixion nail is most suitable for use in fractures where torsional loads across the fracture site are shared between the nail and the bony ends of the fracture, as in a spiral fracture.

[Correction of lower limb deformity by using an expandable nail system. Adaption of osteosynthesis to dystrophe soft-tissue situation]

Operative procedures on the lower limb demand crucial handling of the surrounding soft tissues. Otherwise skin necrosis may develop and in cases of overlapping to the bone there is a risk of osteitis. Therefore the operative treatment requires an approach which reduces operative trauma to a minimum. However, in some cases even a minimal incision is too traumatic. The case we present, describes the use of an expandable nail-system to correct a valgus deformity in a lower limb, years after radiation therapy for synovial sarcoma. The distinctiveness in this case is the dystrophic skin after irradiation and the surgical options for correction.

Expandable intramedullary nailing for tibial and femoral fractures: a preliminary analysis of perioperative complications

OBJECTIVE

To report the results of using the expandable nailing system in the treatment of femoral and tibial shaft fractures.

DESIGN

Prospective, cohort series.

SETTING

Two level-1 university trauma centers.

PARTICIPANTS

Forty-eight patients with acute, traumatic diaphyseal fractures of the tibia or femur.

INTERVENTION

Internal fixation of lower extremity long bone fractures using expandable intramedullary nailing.

MAIN OUTCOME MEASUREMENTS

Perioperative complications and time to healing.

RESULTS

Forty-nine long bone fractures were treated: 22 femoral fractures (OTA classification: 4 type A1, 6 A2, 7 A3, 1 B1, and 4 B2) and 27 tibial fractures (OTA classification: 4 type A1, 11 A2, 9 A3, 0 B1, and 3 B2). There were 13 open fractures and 37 closed fractures. Healing occurred in 37 (75%) fractures without additional interventions. There were 2 tibial delayed unions and 1 femoral and 1 tibial nonunion. Five tibial shaft fractures and 6 femoral fractures shortened by 1.0 cm or more postoperatively. In 3 tibias and 4 femurs, shortening occurred after fractures judged to be length-stable became unstable because of fracture propagation during nail expansion. Five tibias and 3 femurs were converted to standard locked nails because of shortening. The average time to healing, excluding nonunion, was 15 weeks in the tibia and 16 weeks in the femur. The expandable nail resulted in an unplanned reoperation in 12 cases (25%).

CONCLUSION

We found a high complication rate because of shortening, which was independent of fracture classification. Consequently, we cannot recommend the use of an unlocked, expandable nail in diaphyseal fractures of the femur or tibia.

Bending and torsional stiffness in cadaver humeri fixed with a self-locking expandable or interlocking nail system: a mechanical study

OBJECTIVES

This study was designed to gain data about a new expandable, noninterlocked intramedullary nail's capacity to stabilize unstable transverse humeral shaft fractures without the need for interlocking, thus making nail implantation simpler and to prove our goal hypothesis: that in a midshaft osteotomy of the humeral shaft the expandable humeral nail will show the same bending and torsional stiffness as an interlocked humeral nail, when implanted correctly according to the manufacturer's instructions.

DESIGN

Pair randomization.

SETTING

Mechanical laboratory testing.

PARTICIPANTS

Eight pairs of freshly harvested cadaveric humeri.

INTERVENTIONS

Fracture model was a midshaft transverse osteotomy, gapped to 3 mm. Each humerus pair received an expandable humeral nail (Fixion) or an interlocked humerus nail (Synthes) through a retrograde approach. The humeri were fixed in polymethylmethacrylate cylinders and tested in a servo-pneumatic material-testing machine.

MAIN OUTCOME MEASUREMENTS

Torsional stiffness and bending stiffness of the nail-bone-construction.

RESULTS

Expandable nails (interlocked nails) showed a lateral bending stiffness of 0.73 +/- 0.14 (0.63 +/- 0.1) KN/mm (P = 0.026) and a frontal bending stiffness of 0.67 +/- 0.18 (0.58 +/- 0.09) KN/mm (P = 0.084). Torsional stiffness values were 0.13 +/- 0.19 (0.43 +/- 0.09 Nm/degrees) (P = 0.012). Lower torsional stiffness in the expandable nail group was observed in humeri with a funnel shaped proximal intramedullary canal.

CONCLUSIONS

The nail systems showed similar characteristics for frontal bending (P = 0.084), but not for lateral bending (P = 0.026). For lateral bending, the Fixion nail showed significantly more stiffness than the UHN nail (P = 0.026). There was significantly lower torsional stiffness with expandable nails compared with interlocked nails. Clinical correlation would suggest that in rotationally unstable fractures (A2 and A3 diaphyseal fractures), interlocked nails would provide increased stability over expandable nails.

Intramedullary nailing of the femur with an inflatable self-locking nail: comparison with locked nailing

We report a comparative study between an inflatable expandable nail and a traditional locked intramedullary implant in closed fractures of the femoral shaft. We matched each of 43 patients who had undergone intramedullary fixation with an inflatable expandable nail with a patient of the same sex, age (within 2 years), and fracture who had undergone statically locked intramedullary fixation with traditional nails. The mean duration of surgery was significantly shorter in the patients who were treated with the inflatable expandable nail. There were no differences in average blood loss, transfusion requirements, or hospitalization. Five of the patients who underwent traditional nailing required dynamization to achieve union. The inflatable expandable nail allows effective management of diaphyseal fractures of the femur. Interlocking is not necessary, operative times are reduced, and exposure to ionizing radiation is minimized. At present, however, the inflatable expandable nail used in the this investigation is markedly more expensive than traditional devices.