Intramedullary nailing of femoral shaft fractures: current concepts

Radiographic outcomes and non-union factor analysis in fragmentary segmental femoral shaft fractures (AO/OTA 32C3) treated with reamed antegrade nailing

This study retrospectively assessed radiographic outcomes and risk factors associated with non-union in femoral shaft fragmentary segmental fractures (AO/OTA 32C3) treated with reamed antegrade intra-medullary nailing. Radiological outcomes, including union and alignment, were evaluated. The risk factors for non-union were investigated, including demographics and treatment-related characteristics, such as the number of interlocking screws, segmentation length, main third fragment length, distance of the main third fragment, width ratio and exposed nail length in one cortex from immediate post-operative radiographs. Multivariate logistic regression was used for statistical analysis. Among 2295 femoral shaft fracture patients from three level-1 trauma centers, 51 met the inclusion criteria. The radiological union was achieved in 37 patients (73%) with a mean union time of 10.7 ± 4.8 months. The acceptable axial alignment was observed in 30 patients (59%). Multiple logistic regression analysis identified only exposed nail length as a significant risk factor for non-union (odds ratio: 1.599, p = 0.003) and the cut-off value was 19.1 mm (sensitivity, 0.786; specificity, 0.811). The study revealed high rates of non-union (27%) and malalignment (41%). Therefore, patients who underwent intramedullary nailing with an exposed nail length greater than 19.1 mm or about twice the nail diameter should be cautioned of the potential non-union.

Comprehensive Review on Distal Femur Fractures: From Epidemiology to Treatment Strategies

Distal femur fractures present a substantial orthopedic challenge, necessitating a comprehensive exploration spanning epidemiology, anatomy, classification, diagnosis, and treatment strategies. This review thoroughly analyzes the multifaceted aspects surrounding distal femur fractures. It delves into the definition and epidemiology, shedding light on the incidence, age distribution, and associated risk factors. An exhaustive examination of the distal femur's anatomy, encompassing ligaments and tendons, establishes the groundwork for understanding fracture patterns and subsequent classification according to the AO Foundation/Orthopaedic Trauma Association (AO/OTA) system. Diagnostic considerations encompass physical examination and various imaging modalities, emphasizing the critical importance of prompt and accurate assessment. The extensive discussion on treatment options ranges from non-surgical management, including casting and traction, to surgical interventions, such as open reduction and internal fixation, intramedullary nailing, and external fixation. The implications for clinical practice underscore the necessity for tailored approaches based on fracture characteristics to optimize patient outcomes. However, this review also emphasizes areas necessitating further investigation, including exploring predictive biomarkers, advanced surgical techniques, and innovative rehabilitation protocols. Insights from long-term outcomes and quality-of-life assessments in diverse populations offer promising avenues for enhancing the comprehensive management of distal femur fractures. Continuous research in these areas can refine treatment strategies and elevate the standard of care for individuals grappling with this intricate orthopedic condition.

Comparing outcomes of plate augmentation, nail exchange, and nail exchange with plate augmentation in the treatment of atrophic femoral shaft nonunion after intramedullary nailing: a multicenter retrospective study

INTRODUCTION

Intramedullary (IM) nailing is the treatment of choice for femoral shaft fractures, but nonunion rates have been reported to be as high as 12%. Surgical interventions for nonunion involve exchange nailing or plate augmentation. Recently, a combined treatment of exchange nailing and plate augmentation has demonstrated good results, but its comparative effectiveness remains unclear. This study aimed to compare the clinical and radiographic outcomes of three different surgical interventions for atrophic femoral shaft nonunion, and investigate the factors that affect bone healing after reoperation.

MATERIALS AND METHODS

A retrospective study was conducted at five university hospitals involving 149 patients with aseptic atrophic nonunion after IM nailing. These patients underwent reoperation with plate augmentation, exchange nailing, or combined treatment. Clinical and radiographic outcomes were assessed and compared according to reoperation procedure. Logistic regression analysis was performed to identify factors affecting persistent nonunion after reoperation.

RESULTS

Of the cohort, 57 patients underwent plate augmentation, 64 underwent exchange nailing, and 28 received combined treatment. There were no significant differences in patient demographics among the groups. Exchange nailing produced a significantly lower union rate than did the combined treatment (82.8% vs. 100%, p = 0.016), whereas no significant difference was observed in the union rate and time to the union between plate augmentation and the combined treatment. Combined treatment showed the longest operative time and the greatest transfusion requirements. The risk factors for persistent nonunion included age, absence of autogenous bone grafts, and use of an exchange nailing technique.

CONCLUSIONS

Exchange nailing as a treatment for atrophic femoral shaft nonunion after IM nailing resulted in a lower union rate. The efficacy of the combined treatment requires further study, and persistent nonunion may be influenced by age, bone grafting, and surgical techniques. A comprehensive approach targeting both biological environment and mechanical stability is crucial in the treatment of atrophic femoral shaft nonunion.

Effect of postoperative fracture gap on bone union: A retrospective cohort analysis of simple femoral shaft fractures

BACKGROUND

Intramedullary nailing (IMN) is considered the gold-standard treatment for femoral shaft fractures. The post operative fracture gap is commonly recognized as a risk factor for nonunion. However, no evaluation standard for measuring the fracture gap size has yet been established. In addition, the clinical implications of the fracture gap size have also not been determined so far. This study aims to clarify how we should evaluate fracture gaps when assessing simple femoral shaft fractures with radiographs and to determine the acceptable cut-off value of the fracture gap size in simple femoral shaft fractures.

METHOD

A retrospective observational study with a consecutive cohort was conducted at the trauma center of a university hospital. We investigated the fracture gap using postoperative radiography and the postoperative bone union of transverse and short oblique femoral shaft fractures fixed by IMN. The receiver operating characteristic curve analysis was conducted to obtain the fracture gap's mean, minimum, and maximum cut-off values. Fisher's exact test was used at the cut-off value of the most accurate parameter.

RESULTS

In the four nonunions among the 30 cases, the analysis using ROC curves revealed that the maximum value had the highest accuracy among the maximum, minimum, and mean values of fracture-gap size. The cut-off value was determined to be 4.14 mm with high accuracy. Fisher's exact test showed that the incidence of nonunion was higher in the group with a maximum fracture gap of 4.14 mm or greater (risk ratio = not applicable, risk difference = 0.57, P = 0.001).

CONCLUSION

In simple transverse and short oblique femoral shaft fractures fixed with IMN, the fracture gap on radiographs should be evaluated by the maximum gap in the AP and lateral views. The remaining maximum fracture gap of ≥4.14 mm would be a risk factor for nonunion.

In vivo evaluation of a polyester and fiberglass composite intramedullary nail for femoral osteosynthesis in calves

The objective of this study was to test a composite of polyester resin and fiberglass in the form of an intramedullary nail for osteosynthesis of femoral fractures in calves. The methodology was established based on a previous study that used a bovine femur finite element model to simulate fractures, which were then stabilized by the same nails as proposed in this study. General anesthesia was induced in six calves followed by fracture creation via an oblique incision in the middle third of the femoral diaphysis, and osteosynthesis was immediately performed by retrograde insertion of the composite nail. Locking was achieved by drilling the bone and nail without using a jig and introducing two stainless steel screws proximal and two distal to the fracture line. Five of the six calves achieved complete fracture healing after 60 days. No signs of incompatibility or toxicity of the composite were observed. However, limitations were observed during the surgery, such as difficulty in drilling the nail and trimming the remainder portion of the nail that extended beyond the length of the bone. Small fragments produced by these maneuvers were considered irritating to soft tissues during the postoperative period. It was also found that small cracks in the nail tended to propagate in the form of longitudinal fractures. In conclusion, an intramedullary nail made of polyester resin and fiberglass (a low-cost and easy-to-acquire material) was considered biocompatible and capable of allowing bone healing of femoral fractures in young cattle. However, the development of solutions for the reported limitations is crucial prior to recommending the proposed composite for clinical use.

Unplanned reoperation is common following intramedullary nailing of open femoral shaft fractures: A retrospective review

Background

The objective of this study is to investigate the incidence of unplanned reoperation, nonunion and infection following open femoral shaft fractures treated with an intramedullary nail and correlate these occurrences with patient variables and injury characteristics.

Methods

A retrospective review of open femur fractures from a level 1 trauma center between 2012 and 2020 was performed. Ninety-five patients who sustained an open femur fracture, were treated definitively with an intramedullary nail, and had at least 3 months of follow-up were included in the analysis for surgical site infection. Seventy-three of these patients had at least one year of follow-up. After excluding planned bone grafting for segmental defects, 67 patients were included in the analysis of unplanned reoperation.

Results

The rate of unplanned reoperation was 31.3 %, with 57 % of these operations occurring to address nonunion. The overall nonunion rate was 18 %. In patients who did not require reoperation to obtain union, the median time to union for the cohort was 6 months, with an interquartile range of 3-7.5 months. Post-operative surgical site infection occurred in 11.6 % of patients.

Conclusions

In conclusion, unplanned reoperation following intramedullary nailing of open femur fractures occurs in nearly 1/3rd of patients and the rates of nonunion and surgical site infection may be higher than previously reported in the literature. Reoperation most closely correlates with the OTA Open Fracture Classification System. Patients with open femur fractures should be counseled that reoperation is often required to obtain fracture union, with soft tissue and fracture injury severity predicting complications.

Feasibility of a Novel Fluoroscopic Trainer for the Orthopaedic Trainee

OBJECTIVE

We sought to create a novel method of teaching orthopedic trainees to efficiently obtain intraoperative radiographs using nonfluoroscopic digital cameras. Specifically, teaching them to make minor, uniplanar, adjustments while limiting the number of fluoroscopy images obtained during placement of a guidewire "start-point," for intramedullary nailing.

DESIGN

Prospective cohort study including medical students from 2 academic centers. Two nonfluoroscopic digital cameras simulating orthogonal fluoroscopic images were utilized. A sponge was used to simulate soft tissue resistance while navigating a guidewire to the desired starting point. Three cannulated parallel cylinders in a triangular configuration are used to simulate our "start point." Students completed 4 phases; trial and error, teaching, testing and retention.

SETTING

The protocol was completed at a single academic teaching hospital at the primary authors institution.

PARTICIPANTS

We utilized medical students from 2 GME accredited medical schools to complete the protocol. Students were selected from orthopedic surgery interest groups at their respective institutions and participation was voluntary.

RESULTS

Twenty-one medical students completed the protocol. The number of seconds to achieve each target along with the number of pictures to achieve each target were recorded and averaged. The paired t-test was used to compare the difference between phases. There is a statistically significant difference in the mean number of seconds to achieve each target between phase 1 (baseline) and phase 3 (testing) (p < 0.0001). This statistically significant difference was retained in phase 4 (retention) (p < 0.0001).

CONCLUSIONS

We were able to demonstrate a statistically significant decrease in the number of images and time to obtain the correct "start point." This could theoretically decrease operative time and morbidity while teaching students in a low-stress training environment without exposure to radiation.

Nail-extraction device mismatch: an issue in developing countries intramedullary nail removal practice

PURPOSE

Intramedullary nail is the gold standard in the management of long bone diaphyseal fractures of tibia and femur. The jig of these nails has corresponding extraction device whose pitch for nail coupling come in various sizes. This unlike plate and screws may be difficult to predict preoperatively and may pose a problem during removal. Difficulties in removal may arise due to the proliferation of nail brands especially in developing countries. The study aims to identify the incidence of extraction device mismatch among orthopaedic surgeons in Nigeria as well as the indications and complications associated with intramedullary nail removal.

METHODS

A two-page questionnaire was administered to 87 orthopaedic surgeons attending the Annual General Meeting of the Nigerian Medical Association. The attitudes of the participants towards intramedullary nail were assessed.

RESULTS

All participants agree to asymptomatic removal. Patients wish was the leading indication for asymptomatic removal among the participants. Sixty-one percent of the surgeons have had the need to remove a nail different from the brand in the hospital their practice. The commonest indication for symptomatic removal was infections. Forty-seven percent of the participant encountered nail extraction-device mismatch.

CONCLUSIONS

The incidence of extraction device mismatch may portend a public health issue. There may be need for patient who had intra medullary nail insertion to be told their brand. We advocate for standardization of extraction device pitch for intramedullary nail.

Management of Ipsilateral Fractures After Rotationplasty: A Report of 2 Cases and Review of the Literature

CASE

Rotationplasty is a surgical procedure used for restoring functionality after skeletal tumor resection. Multiple complications have been described, including the potential occurrence of fractures. Literature on fracture management after rotationplasty is limited. In this article, we present 2 cases of late ipsilateral fractures in rotated limbs successfully treated with intramedullary nailing.

CONCLUSION

Effective management of fractures after rotationplasty requires thorough understanding of the rotated limb anatomy and careful planning. The clinical considerations presented in this article aim to provide guidance for surgeons to achieve successful outcomes in the management of fractures after rotationplasty.

Retrograde intramedullary nailing of the femur: identifying the true anatomic axis for the ideal start point

PURPOSE

Retrograde femoral intramedullary nailing (IMN) is commonly used to treat distal femur fractures. There is variability in the literature regarding the ideal starting point for retrograde femoral IMN in the coronal plane. The objective of this study was to identify the ideal starting point, based on radiographs, relative to the intercondylar notch in the placement of a retrograde femoral IMN.

METHODS

A consecutive series of 48 patients with anteroposterior long-leg radiographs prior to elective knee arthroplasty from 2017 to 2021 were used to determine the femoral anatomic axis. The anatomic center of the isthmus was identified and marked. Another point 3 cm distal from the isthmus was marked in the center of the femoral canal. A line was drawn connecting the points and extended longitudinally through the distal femur. The distance from the center of the intercondylar notch to the point where the anatomic axis of the femur intersected the distal femur was measured.

RESULTS

On radiographic review, the distance from the intercondylar notch to where the femoral anatomic axis intersects the distal femur was normally distributed with an average distance of 4.1 mm (SD, 1.7 mm) medial to the intercondylar notch.

CONCLUSION

The ideal start point, based on radiographs, for retrograde femoral intramedullary nailing is approximately 4.1 mm medial to the intercondylar notch. Medialization of the starting point for retrograde intramedullary nailing in the coronal plane aligns with the anatomic axis. These results support the integration of templating into preoperative planning prior to retrograde IMN of the femur, with the knowledge that, on average, the ideal start point will be slightly medial. Further investigation via anatomic studies is required to determine whether a medial start point is safe and efficacious in patients with distal femur fractures treated with retrograde IMNs.

Mechanical evaluation of revision surgery for femoral shaft nonunion initially treated with intramedullary nailing: Exchange nailing versus augmentation plating

INTRODUCTION

Exchange nailing (EN) or augmentation plating (AP) has been employed to treat nonunions after intramedullary nailing for femoral shaft fractures. Although instability is a factor in hypertrophic nonunion, mechanical evaluations have been limited because the contribution of the callus to fracture site stability varies with healing. Our previous study illustrated the potential for evaluation using a finite element analysis (FEA) that incorporates callus material properties. This study aimed to mechanically evaluate revision surgery for nonunions using FEA.

MATERIALS AND METHODS

A quantitative computed tomography-based FEA was performed on virtual revision models of a patient with suspected nonunion after intramedullary nailing. In addition to the initial nailing model (IN) with an 11-mm diameter (D) and 360-mm length (L), four EN models with D12mm (EN1), D13mm (EN2), D12mm-L400mm (EN3), and D13mm-L400mm (EN4) nails and three AP models with 5- (AP1), 6- (AP2), and 7-hole (AP3) plates were created. As with bone, callus was assigned inhomogeneous material properties derived from density based on an empirical formula. The hip joint reaction force and muscle forces at maximum load during the gait cycle were applied. The volume ratio of the callus at the fracture site with a tensile failure risk of ≥1 (tensile failure ratio) and bone fragment movement were evaluated.

RESULTS

The tensile failure ratio was 11.6 % (IN), 10.1 % (EN1), 6.3 % (EN2), 10.9 % (EN3), 6.2 % (EN4), 6.4 % (AP1), 7.2 % (AP2), and 7.7 % (AP3), respectively. The bone fragment movement showed an opening on the lateral side with the initial intramedullary nailing. However, both revision surgeries reduced the opening, leading to compression except in the EN1 model. The proximal bone fragments were internally rotated relative to the distal fragments, and the rotational instability was more suppressed in models with lower tensile failure ratio.

CONCLUSIONS

For EN, the increase in diameter, not length, is important to suppress instability. AP reduces instability, comparable to a 2 mm increase in nail diameter, and screw fixation closer to the fracture site reduces instability. This study suggest that AP is mechanically equivalent to EN and could be an option for revision surgery for femoral shaft nonunions.

Open versus closed intramedullary nailing of femur shaft fractures in adults: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to compare the outcomes of open- versus closed-reduction and intramedullary nailing (IMN) of adult femur shaft fractures.

METHODS

Four databases were searched from inception until July 2022 for original studies that compared the outcomes of IMN following open-reduction versus closed-reduction technique. The primary outcome was the union rate; the secondary outcomes were time to union, nonunion, malalignment, revision, and infection. This review was conducted in line with PRISMA guidelines.

RESULTS

A total of 12 studies with 1299 (1346 IMN cases) patients were included, with a mean age of 32.3 ± 3.25. The average follow-up was 2.3 ± 1.45 years. There was a statistically significant difference in union rate (OR, 0.66; 95% CI, 0.45-0.97; p-value, 0.0352), nonunion (OR, 2.06; 95% CI, 1.23-3.44; p-value, 0.0056), and infection rate (OR, 1.94; 95% CI, 1.16-3.25; p-value, 0.0114) between the open-reduction and closed-reduction groups in favour of the latter. However, malalignment was significantly higher in the closed-reduction group (OR, 0.32; 95% CI, 0.16-0.64; p-value, 0.0012), whereas time to union and revision rates were similar (p = NS).

CONCLUSION

This study showed that closed-reduction and IMN had more favourable union rate, nonunion, and infection rates than the open-reduction group, yet malalignment was significantly less in the open-reduction group. Moreover, time to union and revision rates were comparable. However, these results must be interpreted in context due to confounding effects and the lack of high-quality studies.

Optimizing the Entry Point for Reconstruction Nailing of the Femur

INTRODUCTION

Varus after antegrade medullary nailing of the proximal femur is associated with worse outcomes. Anecdotally, a more medialized "trochiformis" entry is beneficial to avoid varus with valgus-bend (greater trochanteric entry) femoral nails. However, the optimal entry point remains unknown. The purpose of this study was to define the optimal entry point for reconstruction nailing.

METHODS

Using standing alignment radiographs from 51 patients, we templated the ideal entry point for straight and valgus-bend nails from three major manufacturers using TraumaCad software. We measured the distance from the tip of the trochanter to the ideal entry site for each nail. We compared piriformis (PF) with trochanteric (GT) entry for each company and across manufacturers.

RESULTS

The mean greater trochanter offset from the femoral axis was 15.2 mm. The mean PF entry was 5.9 to 6.7 mm medial to the mean GT entry for each company's nail and was statistically distinct. No differences were observed in GT and PF entry points across manufacturers. Only 2 of 153 ideal GT entry points were lateral to the tip of the trochanter. An increased neck-shaft angle (NSA) and increased GT offset were correlated with a more medial ideal entry point.

DISCUSSION

The ideal entry point for GT nails is similar across manufacturers and is medial to the tip of the greater trochanter; however, PF and GT entry sites remain distinct. During preoperative planning and when executing femoral nailing intraoperatively, it may also be important to consider the NSA and GT offset of a patient before committing to a certain entry point.

Open and closed reduction methods for intramedullary nailing of femoral shaft fractures: A systematic review and meta-analysis of comparative studies

Introduction

Closed reduction and intramedullary nailing is the preferred surgical intervention for femoral shaft fractures. Open reduction involves opening the fracture site and is performed in various circumstances. Comparative studies of the approaches have conflicting results. We sought to compare the outcomes and complications of open and closed reduction for intramedullary nailing of femoral shaft fractures.

Materials and methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, a systematic review of comparative studies included the databases and registers PubMed (Medline), Embase, Scopus, and Cochrane Central (PROSPERO registration ID: CRD42022325382). Additional studies were identified through hand and citation searching. Two reviewers independently extracted data. The standardized mean difference and 95% confidence intervals were determined for continuous variables, whereas odds ratios and 95% confidence intervals were assessed for dichotomous variables.

Results

Closed reduction had a higher pooled union rate (93.93%, 92.02%), an increased odds ratio for union (OR = 1.624 [95% CI: 1.004, 2.624]; p = .048), and a faster time to union (SMD = -0.292 [95% CI: -0.549, -0.0.035]; p = .026). There were no differences in operative time (SMD = 0.128 [95% CI: -0.700, 0.956] p = .762) or overall complication rate (OR = 1.314 [95% CI: 0.966, 1.787] p = .082).

Conclusions

Closed reduction has the advantage of higher union rates, quicker time to union, and lower overall infection compared to open reduction for intramedullary nailing of femoral shaft fractures. Open reduction remains a reasonable alternative with acceptable union rates when closed reduction is not feasible.

Intramedullary reamer failure in orthopaedic surgery: Two case reports and practical recommendations for prevention

Intramedullary reaming has been proven to be a safe and effective method for enhancing the union rates of long bone fractures. However, there is a risk of equipment failure, which can lead to severe complications. We present two cases of reamer failure during femoral nailing which illustrate the rare occurrence of intraoperative instrument failure. Our report also underscores the importance of routinely inspecting reaming equipment and provides technical insights to reduce the risk of failure.

Application of femoral nail, reconstruction locked plate and bone morphogenic protein - 7 in an osteopetrosis patient with a recurrent femoral shaft fracture: A case report

INTRODUCTION AND IMPORTANCE

Femoral fractures are common in the patients with osteopetrosis and multiple treatment strategies have been described with varying results. However, there is a paucity of literature describing the treatment of recurrent fractures and subsequent deformity.

CASE PRESENTATION

We present detailed revision strategies and long-term follow-up results of a patient with osteopetrosis who suffered unsuccessful operative treatment using the plate-screw system (recurrent femoral shaft fracture and implant failure).

CLINICAL DISCUSSION

The success of revision surgery of osteopetrosis is based on good preoperative planning, appropriate selection of fixation methods, and a meticulous approach during surgery. The combined application of the expert adolescent lateral femoral nail, the reconstruction locked plate, and bone morphogenic protein (BMP)-7 in this patient achieved good clinical results.

CONCLUSION

In the treatment of failed plated and recurrent osteopetrotic femoral shaft fractures, the combination of nails and plating presents an alternative, potentially more successful, revision strategy.

A retrospective review of the rate of septic knee arthritis after retrograde femoral nailing for traumatic femoral fractures at a single academic institution

Background

Retrograde intramedullary nailing of the femur is a popular treatment option for femoral shaft fractures. However, this requires accessing the intramedullary canal through the knee, posing a risk of intra-articular infection. The purpose of this study was to examine the rate of intra-articular infection of the knee after retrograde nailing of femoral shaft fractures.

Methods

All patients who underwent retrograde intramedullary nailing for femoral shaft fractures between June 2004 and December 2017 at a level 1 trauma center were reviewed. Six months of follow-up or documented fracture union was required. Records were reviewed for documentation of septic arthritis of the ipsilateral knee during the follow-up period.

Results

A total of 294 fractures, including 217 closed and 77 open injuries, were included. Eighteen had an associated ipsilateral traumatic arthrotomy; 188 cases had an associated ipsilateral lower extremity fracture. No cases of septic arthritis were identified.

Conclusion

There were no cases of septic arthritis in 294 fractures treated with retrograde intramedullary nailing. Retrograde nailing appears safe for risk of postoperative septic arthritis of the knee even in the face of open fractures and traumatic wounds.

A multicenter study of factors affecting nonunion by radiographic analysis after intramedullary nailing in segmental femoral shaft fractures

The factors affecting the outcomes of segmental femoral shaft fractures are currently unknown. We evaluated the outcomes of intramedullary (IM) nail fixation and investigated factors affecting nonunion of femoral shaft segmental fractures. A total of 38 patients who underwent IM nail fixation for femoral shaft segmental fractures (AO/OTA 32C2) at three university hospitals with a minimum 1-year follow-up period were retrospectively reviewed. The patients were divided into union (n = 32) and nonunion (n = 6) groups. We analyzed smoking status, diabetes mellitus, location of the segmental fragment, segment comminution, filling of the IM nail in the medullary canal, residual gap at the fracture site, use of a cerclage wire or blocking screws as factors that may affect the surgical outcome. In the union group, the average union time was 5.4 months (4-9 months). In the nonunion group, five patients required additional surgery within an average of 7.2 months (5-10 months) postoperatively, whereas one patient remained asymptomatic and did not require further intervention. On comparing the two groups, insufficient canal filling of the IM nail (union, 25.0%; nonunion, 83.3%; p = 0.012) and the presence of a residual gap at the fracture site after reduction (union, 31.3%; nonunion, 83.3%; p = 0.027) were significantly different. In the multivariate analysis, only insufficient canal filling of the IM nail was found to be a factor affecting nonunion, with an odds ratio of 13.3 (p = 0.036). In this study, a relatively high nonunion rate (15.8%) was observed after IM nail fixation. Insufficient IM nail canal filling and a residual gap at the fracture site post reduction were factors affecting segmental femoral shaft fracture nonunion after IM nail fixation.

Small residual fracture gaps delay time to union in length stable femur fractures treated with intrameduallary fixation

OBJECTIVES

The purpose of this study was to investigate whether residual fracture gapping and translation at time of intramedullary nail (IMN) fixation for diaphyseal femur fractures were associated with delayed healing or nonunion.

DESIGN

Retrospective cohort study SETTING: Level 1 trauma hospital, quaternary referral center PATIENTS/PARTICIPANTS/INTERVENTION: Length stable Winquist type 1 and 2 diaphyseal femur fractures treated with IMN at a single Level I trauma center were retrospectively reviewed.

MAIN OUTCOME MEASURE

The largest fracture gap and translation were evaluated on immediate anteroposterior (AP) and lateral postoperative radiographs. Radiographic healing was assessed using Radiographic Union Score in Femur (RUSF) scores at each follow-up. Radiographic union was defined as a RUSF score ≥8 and consolidation of at least 3 cortices. ANOVA and student's t-tests were used to evaluate the influence of fracture gap parameters on time to union (TTU) and nonunion rate. Patients were stratified to measured average gap and translation distances <1mm, 1-3mm and >3mm for portions of the analysis.

RESULTS

Sixty-six patients who underwent IMN with adequate follow-up were identified. A total of 93.9% of patients achieved union at an average of 2.8 months. Fractures with average AP/lateral gaps of <1mm, 1-2.9 mm, and >3mm had an average TTU of 70.1, 91.7, and 111.9 days respectively; fractures with larger residual gap sizes had a significantly longer TTU (p=0.009). Fractures with an average gap of 1-2.9mm and >3 mm had a significantly higher nonunion rate (1.5% and 4.5% respectively) compared to 0% nonunion in the <1 mm group (p=0.003).

CONCLUSION

Residual gapping following intramedullary fixation of length stable diaphyseal femur fractures is associated with a significant increase in likelihood of nonunion.

SUMMARY

Residual displacement of length stable femoral shaft fractures following intramedullary nailing can have a significantly negative impact on fracture healing. An average 3 mm AP/lateral residual fracture gap or a total of 6 mm of the AP + lateral fracture gap appeared to be a critical gap size with increased rates of nonunion and time to union. Therefore, we suggest minimizing the sum of the residual AP and lateral fracture gap to less than a total of 6 mm.

Elbow to digit measurements as a preoperative adjunct tool to aid intramedullary femoral nail selection - the rule of thumb

BACKGROUND

Intramedullary femoral nails are measured intraoperatively using fluoroscopy. This study aims to investigate whether distance from the olecranon to fingertips can be used to estimate nail length preoperatively by evaluating agreement of the two measurements. Such preoperative measurements may provide a likely range of nails needed for theatre and serve as an adjunct to intraoperative measurements.

METHODS

In 70 patients, long leg radiographs were used to make linear measurements from the piriformis fossa and greater trochanter to the distal physeal scar of the femur. These were compared to measurements from the olecranon to the tip of each digit and Bland-Altman agreement analysis was performed. Train and Trial groups were formed to develop models for estimation and to then test their accuracy.

RESULTS

Bland-Altman analysis revealed a fixed bias, indicative of average difference between measurements, of 1.4 cm when comparing the elbow-thumb length to maximum femoral nail length for piriformis fossa entry and 3.5 cm using greater trochanter entry, informing the "rule of thumb". Elbow-thumb length plus 1.4 cm or 3.5 cm predicts nail length to a range of ± one nail increment. The rule can be used to preoperatively predict a range of three nails from which there is a 94-97% likelihood the appropriate intramedullary nail would be selected.

CONCLUSIONS

The "rule of thumb" may serve as a simple to use tool for preoperative planning and a technical check to assess the "reasonableness" of intraoperative measurements before implantation of the device. It has the potential to reduce operating time and nail wastage.

Effect of nailing technique on length of stay in isolated ballistic femoral shaft fractures

PURPOSE

The purpose of this study was to investigate length of stay, postoperative mobilization and discharge disposition following intramedullary nailing of ballistic femoral shaft fractures stratified by nailing technique.

METHODS

All adult patients with isolated ballistic femoral shaft fractures between May 1, 2018, and September 1, 2021, were reviewed. The final cohort included 69 ballistic femur fractures in 69 patients. Of the 69 patients included, 29 were treated with retrograde nailing while 40 were treated with antegrade nailing.

RESULTS

The average length of stay of patients treated with antegrade nailing was 2.55 days (SD 1.3 days) compared with 3.45 days (SD 2.3 days) for patients treated with retrograde nailing; this was statistically significant (P = 0.04). Median steps on POD1 for antegrade nailing were 20 and 8 for retrograde. There was no significant difference in VAS pain scores between the two cohorts. All patients were discharged home.

CONCLUSION

The average length of stay for patients who underwent antegrade nailing was significantly shorter when compared with the retrograde nailing. Patients in the antegrade cohort mobilized further than the retrograde cohort in the immediate postoperative setting. We found no significant difference in VAS pain scores between the two cohorts.

LEVEL OF EVIDENCE: 3

Technique for Extraction and Revision of a Bent Intramedullary Nail for a Subtrochanteric Femur Fracture: A Case Report

CASE

A 17-year-old adolescent boy presented 2 months after initial intramedullary nail (IMN) fixation of a comminuted subtrochanteric fracture with refracture at the previous site and approximately 20° varus angulation of the nail. The bent femoral nail was successfully extracted using an open technique using Lohman bone-holding clamps and a broad plate. At the 1-year follow-up, fracture union was achieved.

CONCLUSIONS

Removal of a deformed IMN is rare. No standardized protocol exists in guiding orthopaedic surgeons. A thorough review of techniques is discussed on this unusual complication.

Optimal concentration of mesenchymal stem cells for fracture healing in a rat model with long bone fracture

BACKGROUND

There is still no consensus on which concentration of mesenchymal stem cells (MSCs) to use for promoting fracture healing in a rat model of long bone fracture.

AIM

To assess the optimal concentration of MSCs for promoting fracture healing in a rat model.

METHODS

Wistar rats were divided into four groups according to MSC concentrations: Normal saline (C), 2.5 × 10⁶ (L), 5.0 × 10⁶ (M), and 10.0 × 10⁶ (H) groups. The MSCs were injected directly into the fracture site. The rats were sacrificed at 2 and 6 wk post-fracture. New bone formation [bone volume (BV) and percentage BV (PBV)] was evaluated using micro-computed tomography (CT). Histological analysis was performed to evaluate fracture healing score. The protein expression of factors related to MSC migration [stromal cell-derived factor 1 (SDF-1), transforming growth factor-beta 1 (TGF-β1)] and angiogenesis [vascular endothelial growth factor (VEGF)] was evaluated using western blot analysis. The expression of cytokines associated with osteogenesis [bone morphogenetic protein-2 (BMP-2), TGF-β1 and VEGF] was evaluated using real-time polymerase chain reaction.

RESULTS

Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture (P = 0.040, P = 0.009; P = 0.004, P = 0.001, respectively). Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture (P = 0.018, P = 0.010; P = 0.032, P = 0.050, respectively). At 2 wk post-fracture, SDF-1, TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L (P = 0.031, P = 0.014; P < 0.001, P < 0.001; P = 0.025, P < 0.001, respectively). BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk post-fracture (P = 0.037, P = 0.038; P = 0.021, P = 0.010). Compared to group L, TGF-β1 expression was significantly higher in groups H (P = 0.016). There were no significant differences in expression levels of chemokines related to MSC migration, angiogenesis and cytokines associated with osteogenesis between M and H groups at 2 and 6 wk post-fracture.

CONCLUSION

The administration of at least 5.0 × 10⁶ MSCs was optimal to promote fracture healing in a rat model of long bone fractures.

Medialized Trochanteric Entry Nailing Is a Safe and Effective Method for High-Energy Subtrochanteric Femur Fracture Treatment

Fixation of subtrochanteric femur fractures using intramedullary nails can provide high rates of osseous union. However, a lateral starting point or a medial trajectory can result in varus alignment, typically seen with trochanteric entry nails. Even with piriformis nails, medial comminution can result in secondary malalignment and varus. Varus can predictably result in nonunion and need for repeat operations. Medialized trochanteric entry nailing has been reported previously as a method to prevent varus alignment in low-energy, atypical subtrochanteric femur fractures in association with bisphosphonate use. We present a surgical technique using a medialized trochanteric nail entry point to provide proper alignment and avoidance of varus malreduction in 24 patients with a subtrochanteric femur fracture after a high-energy traumatic event.

Induced Membrane Technique for the Management of Segmental Femoral Defects: A Systematic Review and Meta-Analysis of Individual Participant Data

Several modifications of the induced membrane technique (IMT) have been reported, but there is no consensus regarding their results and prognosis. Moreover, most studies have focused on tibial defects; no meta-analysis of the treatment of femoral defects using the IMT has been reported. This systematic review and meta-analysis aimed to identify the potential risk factors of post-procedural complications following the treatment of segmental femoral defects using the IMT. A comprehensive search was performed on the Cochrane Library, EBSCO, EMBASE, Ovid, PubMed, Scopus, and Web of Science databases, using the keywords "femur," "Masquelet technique," and "induced membrane technique." Original articles composed in English, having accessible individual patient data, and reporting more than two cases of bony defect or nonunion of femur or more than five cases of any body part were included. Post-procedural bone graft infections, final union status, and union time after second-stage operation were analyzed. Fourteen reports, including 90 patients, were used in this study. External fixation in second-stage surgery had an odds ratio of 9.267 for post-procedural bone graft infection (p = 0.047). The odds ratio of post-procedural bone graft infection and age >65 years for final non-union status was 51.05 (p = 0.003) and 9.18 (p = 0.042). Shorter union time was related to impregnated antibiotics in the spacer (p = 0.005), transplanting all-autologous grafts (p = 0.042), and the application of intramedullary nails as the second-stage fixation method (p = 0.050). The IMT appears to be reasonable and reproducible for femoral segmental bone defects. Several preoperative and surgical factors may affect post-procedural complications and union time.

Antegrade versus retrograde nailing of proximal femur fractures: A cortical diameter based study

Background

Retrograde nailing of proximal femoral shaft fractures is controversial. The purpose of this study was to compare patients with proximal femur fractures undergoing antegrade versus retrograde intramedullary nailing (AIMN vs RIMN) and determine the safety and efficacy of RIMN.

Methods

A retrospective review was performed on 54 patients undergoing femoral IMN for proximal femoral shaft fractures at an urban level one trauma institution between January 2016 and July 2021.Fracture distance from the lesser trochanter (LT) was recorded and used to calculate the number of cortical diameters (NCD) from the LT. Proximal femur fractures were defined as < 3 NCD. AIMN and RIMN fixation was utilized in 31 (57.4%) and 23 (42.6%) patients, respectively. Outcomes measures included pre-/postoperative true translational and angular displacement (TTD and TAD), operative time, estimated blood loss (EBL), union rate, time to union, complications, and reoperations.

Results

AIMN and RIMN groups were similar in terms of age, sex, BMI, tobacco use, diabetes, ASA classification >2, AO/OTA classification, preoperative TTD or TAD, open fractures, or ballistic fractures. The AIMN group, had a shorter measured distance from the LT (47.0 vs. 66.1 mm, p = 0.04) but the difference in NCD was not significant (1.4 vs. 2.0, p = 0.07). Among patients with isolated IMN procedures, the RIMN group had shorter operative times (142.3 vs. 178.5 min, p = 0.01) and less EBL (100 vs. 250 mL, p = 0.008). There was no observed intergroup difference in terms of postoperative TTD/TAD, union rate, time to union, complications, or reoperations.

Conclusion

RIMN is a viable treatment option for proximal femoral shaft fractures that results in less operative time, less blood loss, and no detectable differences in union, reoperations, or complications.

Level of evidence

Level III, Retrospective cohort study.

Interest in curves: when the radius of curvature matters in femur fractures. A CT based morphometric study

PURPOSE

In today's era, fractures of the femur are primarily managed with intramedullary devices. Keeping in mind the anatomical sagittal bow of the femur, intramedullary devices have been devised with an anterior bow, but this varies amongst various manufacturers - leading to complications such as anterior cortex impingement beyond the isthmus and posterior cortical opening at the fracture site. We intend to find the average radius of curvature (ROC) of the anatomical bow of the femur and the variation of the same.

METHODS

Radiographic data of 150 normal femur scans done in 81 patients were loaded in the Mimics 21.0 software (Materialise, Leuven, Belgium). A centerline (of the medullary cavity) was created using the software. A best-fit circle was created in the sagittal plane involving a major part of the centerline, and ROC was calculated.

RESULTS

We found the average ROC of our data was 1027.2, with a standard deviation of 241.55. ROC and length of the femur (an indirect measure of height) had a slight positive correlation (r = 0.36; p < 0.05); and a highly positive correlation in the ROC of the left and right femurs of the same individuals (r = 0.605; p < 0.05).

CONCLUSIONS

The usual ROC of intramedullary nails is commonly > 1300 mm, much higher than the average ROC we identified in our population. Thus, we conclude that implants with smaller ROC in the range of 1100 mm are needed, leading to better implant placement in the canal and avoiding complications of anterior cortex impingement and preventing fracture gap widening in our setting.

Removing a bent femoral nail - man versus metal: A case report

Introduction

Intramedullary nailing is the treatment of choice for femoral shaft fractures in adults with excellent clinical results and low complication rates reported in the literature. However, in situ bending of a femoral nail is a rare complication that merits special attention. While there are several extraction techniques and algorithms the scientific evidence to support these decision-making tools is unconvincing.

Presentation of case

A 26-year old man presented to the Accident and Emergency Department with a deformed thigh following a low-energy injury. Radiographs showed a bent femoral nail in situ and the patient disclosed that he had surgery four weeks earlier for a fractured femur sustained in a motor vehicle accident. A treatment algorithm was followed in planning the surgical strategy, but ultimately a simple hacksaw blade was used to cut and remove the nail. The fracture which was stabilised by exchange nailing went on to uncomplicated union and the patient recovered fully.

Discussion

Non-invasive methods of removing a bent femoral nail are often unsuccessful and may result in iatrogenic injuries. Surgeons should assess the available local resources and first consider using simple open methods when attempting to remove a bent femoral nail.

Conclusion

Open extraction methods often disregard the low-resource environment in which many surgeons work. We describe a simple and economical technique that uses a regular hacksaw blade to cut and remove a bent femoral nail.

•

Using modern implants, insitu bending of a femoral nail is a rare occurrence.

•

Closed extraction methods are often unsuccessful and may lead to iatrogenic injuries.

•

An open technique using a simple hacksaw can be used in low-resource settings without access to sophisticated extraction tools.

Demographic and clinical profile of patients treated with proximal femoral nails - a 10-year analysis of more than 40,000 Cases

Background

Hip fractures are common in elderly populations and can be life threatening. Changes in healthcare delivery and outcomes for patients with hip fracture treated with intramedullary nails are not well characterized. The objectives of our study were: 1) the characterization of patients treated with the Trochanteric Fixation Nail -Advanced™(TFNA) Proximal Femoral Nailing System or comparable nails (index) and estimate 12-month all-cause readmissions (ACR) and reoperations following index; and 2) the evaluation of 10-year healthcare utilization (HCU) trends for treatment of femoral fractures with femoral nails.

Methods

This is a retrospective database analysis using the Premier hospital database. All adults with femoral fracture treated with an intramedullary nail, from 2010 to Q3 2019, in the inpatient setting, were identified. Exclusion criteria included patients with bilateral hip surgery and presence of breakage at time of initial surgery. The primary outcome was ACR and reoperation, the secondary outcomes were healthcare utilization metrics. Variables included demographics, comorbidities (Elixhauser Index (EI)), surgical intervention variables and hospital characteristics.

Results

Forty-one thousand one hundred four patients were included in the study, of which 14,069 TFNA patients, with average age 77.9 (Standard deviation (SD): 12.0), more than 60% with 3 or more comorbidities (more than 64% for TFNA), 40% with severe or extreme disease severity and one third with severe or extreme risk for mortality. ACR reached 60.1% (95% confidence interval (CI): 59.6%-60.5%) – for TFNA: 60.0% (95%CI: 59.2%-60.8%). The reoperation rate was 4.0% (95%CI: 3.8%-4.2%) – for TFNA: 3.8% (95%CI: 3.5%-4.1%). Length of stay (LOS) averaged 5.8 days (SD: 4.8), and 12-month hip reoperation was 4.0% (3.8%-4.2%), in TFNA cohort: 3.8% (3.5%-4.1%). From 2010 to 2019: the percentage patients operated within 48 h of admission significantly increased, from 75.2% (95%CI: 74.3%-76.1%) to 84.3% (95%CI: 83.9%-84.6%); LOS significantly decreased, from 6.2 (95%CI: 6.0–6.4) to 5.6 (95%CI: 5.5–5.7) days; discharge to skilled nursing facilities (SNF) increased from 56.0% (95%CI: 54.8%-57.2%) to 61.5% (95%CI: 60.8%-62.2%); ACR rates decreased but reoperation rates remained constant.

Conclusions

ACR and reoperation rates were similar across device types and averaged 60.1% and 4.0%, respectively. Ten-year analyses showed reductions in hospital HCU and greater reliance on SNF.

Does nail size or difference between canal and nail diameter influence likelihood of union or time to union of femoral shaft fractures treated with intramedullary nailing? A retrospective cohort study

Background

This study aims to determine whether nail size or the difference between canal and nail diameter (CN difference) affects the union rate and time of femoral shaft fracture treated with an interlocking intramedullary nail (IMN).

Methods

This was a retrospective review of 257 patients with femoral shaft fractures treated with IMN at a tertiary trauma medical center. All the IMN inserted were the same (Stryker T2 Femoral Nail). The patients were divided into groups based on nail size (10-, 11-, 12-, or 13-mm) and CN difference (< 1, 1–2, or > 2 mm), and union rate and time to union were compared.

Results

The 10-, 11-, 12-, and 13-mm groups based on nail size had 113, 74, 54, and 16 patients, respectively. The overall union rate was 97% (257/265). No significant differences in union rate or time to union were observed among these 4 groups. The groups based on CN differences of < 1-, 1 to 2, and > 2 mm comprised 143, 79, and 35 patients, respectively. Again, no significant differences were noted in union rate or mean time to union among the groups.

Conclusions

Similar union rate and time to union were observed, regardless of nail size or CN difference. This finding indicates that most simple femoral shaft fractures can be treated with a standard, reamed 10-mm IMN. A larger nail insertion is unnecessary and presents more risks; comparatively, the use of a small nail with less reaming is simpler, requires shorter operative times, results in less blood loss, and is less expensive.

The Butterfly Fragment in Wedge-Shaped Femoral Shaft Fracture: Comparison of Two Different Surgical Methods

Objective

Our study compared the results of wedge‐shaped femoral shaft fracture following intramedullary (IM) nailing with or without fixation of the third fragment.

Methods

We retrospectively reviewed patients presenting with femoral shaft fracture with AO/OTA type 32‐B from 2011 to 2016. Patients were divided into two groups: closed reduction without touching the third fragment and open reduction with fixation of the third fragment. The fragment ratio, fragment length, nail size, dynamization or not, mRUST scores, union rate, and union time were compared between the two groups. Risk factors of non‐union were also investigated, including sex, age, fracture pattern, fracture location, dynamization, nail size, fragment ratio, fragment size, and postoperative fragment displacement.

Results

A total of 80 patients met inclusion criteria, 20 patients with wedge‐shaped shaft femoral fracture were managed with IM nailing and open reduction with fixation of the third fragment. Sixty patients were treated with IM nail without touching the third fragment. The union rate for the fixation and non‐fixation groups were 60.0% and 81.7%, respectively. The mean union time for the fixation group was 19 months vs 14 months for the non‐fixation group. Multi‐regression analysis showed larger nail size (odds ratio: 2.26) and fixation of the third fragment (odds ratio: 0.18) influenced fracture healing.

Conclusions

Fixation of the third fragment in wedge‐shaped shaft femoral fracture results in a longer union time and lower union rate. In the management of femoral fracture with a third fragment, a larger nail size is recommended and fixation should be performed in a closed manner. Fixation of the fragment may achieve better fracture reduction. However, disruption of the vasculature and surrounding structures may further result in nonunion of the fracture site.

The characteristics and influence of iatrogenic fracture comminution following antegrade interlocking nailing for simple femoral shaft fractures, a retrospective cohort study

AIM

The incidence and characteristics of iatrogenic comminution (IC) are unknown, and the influence of IC on fracture union is unclear. This study was aimed to investigate the (1) incidence and characteristics of IC and (2) the outcomes of IC following antegrade interlocking nailing of simple femoral shaft fractures.

METHODS

We retrospectively collected data on patients who experienced simple femoral shaft fractures and underwent antegrade interlocking nailing between February 2009 and December 2016. The incidence and characteristics of IC were examined. According to the presence of IC, patients were divided into two groups: an IC group and a non-IC (NIC) group. Demographic information and nonunion rates were compared between the two groups. Potential risk factors for IC (age, gender, body mass index (BMI), nail fit ratio, reduction technique, and greater trochanter nail entry) were analyzed using univariate and multivariate logistic regression. The aforementioned variables, along with IC occurrence, were also assessed as potential risk factors for nonunion at 12 and 24 months after operation using multivariate logistic regression.

RESULTS

Of the 211 total patients, IC occurred in 20.9% (n = 44) of patients. Most ICs were found at the level of the isthmus, and involved the medial cortex. Compared with the NIC group, higher nonunion rates were observed in the IC group at 12 months (31.8% vs. 12.5%, p = 0.002) and 24 months (18% vs. 6.5%, p = 0.017) after surgery. Age older than 35 years old was related with the occurrence of IC in univariate analysis. Multivariate analysis found no risk factor associated with IC. Open reduction technique, IC occurrence and higher BMI were identified as the risk factors of nonunion at 12 months and 24 months after surgery in multivariate analysis.

CONCLUSION

IC is a non-rare complication in antegrade interlocking nailing of simple femoral shaft fractures and was associated with higher nonunion rate. Age older than 35 years old showed a trend toward increasing risk of iatrogenic fracture comminution. In multivariate analysis, open reduction technique, IC occurrence and higher BMI significantly correlated with fracture nonunion.

LEVEL OF EVIDENCE

Level IV.

Treatment of Recalcitrant Femoral Shaft Nonunion With Medial Femoral Condyle Pedicled Autograft: Technical Trick

SUMMARY

Nonunited fractures of the femoral shaft and distal femur are usually successfully addressed with stabilization with or without autogenous bone grafting. For the small subset of these problems that prove recalcitrant to front-line treatment, a pedicled medial femoral condyle (MFC) bone flap can provide a source of vascularized autograft with minimal donor site morbidity. The MFC has gained recent widespread adoption as a free vascularized bone transfer, and here, we present a surgical technique and retrospective analysis of patients treated with a pedicled MFC technique. This serves as a useful treatment option for these difficult problems and may be especially helpful in low resource environments or where microsurgical anastomosis is not feasible.

One‐Stage Closed Intramedullary Nailing for Delayed Femoral Fracture in Multiple Injured Patients

Objective

To tackle the challengeable dilemma of delayed femoral fracture, a technique of fixator‐assisted closed reduction and intramedullary nailing at one stage was introduced herein and its clinical results were investigated.

Methods

A retrospective study was conducted on delayed femoral shaft fracture between February 2008 and January 2017. The multiple injured patients aged from 18 to 60 years with delayed femoral fracture was included. All patients were treated by one‐stage internal fixation technique and followed up for more than 1 year. Outcome measures including the operation time, intraoperative blood loss and limb alignment, healing time of fracture, visual analog scale (VAS), and range of knee motion were recorded and evaluated.

Results

A total of 13 patients (16 sides) with a mean injury severity score (ISS) of 32.77 ± 9.98 (range, 19 to 52) participated in the investigation. The median length of time‐after‐fracture was 38 days (range, 21 to 110 days). The average shortening distance of the fracture ends was 35.48 ± 19.24 mm (range, 10.00 to 79.00 mm). The average surgery time was 192.19 ± 29.38 min for unilateral femoral fracture, with blood loss of 587.50 ± 232.02 ml. The postoperative discrepancy of lower limb was 3.87 ± 2.52 mm. No patient had vascular and neurologic complications due to the lengthening. All fractures healed successfully with a mean time of 2.98 ± 0.57 months. The mean VAS and maximal knee flexion were 1.63 ± 1.09 and 131.25° ± 5.32° at final follow‐up, respectively.

Conclusions

Our findings indicated that fixator‐assisted closed reduction and intramedullary nailing at one stage is an effective treatment for delayed femoral fracture with satisfactory functional recovery.

Prognostic factors for surgical site infection following intramedullary nailing of diaphyseal fractures of the femur and tibia in adult patients at a tertiary hospital in Lusaka, Zambia

Our study aimed to identify prognostic factors for surgical site infection following long bone fracture intramedullary nailing at a tertiary hospital in a low-resource setting. This was a longitudinal observational study involving 132 participants enrolled over a one-year period with femoral and tibial diaphyseal fractures scheduled for ORIF. Participant median age was 30 years (range: 26 – 42). The prevalence of surgical site infection was 16%. Male sex (AOR=0.26, 95% CI [0.70–0.98]; p = 0.047) was associated with lower odds of surgical site infection while associated non-musculoskeletal injuries were associated with higher odds of developing surgical site infection. Our study confirms a higher surgical site infection rate than normally accepted. However, intramedullary nailing in our setting is justified as it allows an early return to a pre-injury state. These interventions must be carried out in the best possible circumstances. Future studies could explore alternative methods of fracture fixation.

Weight-bearing status may influence rates of radiographic healing following reamed, intramedullary fixation of diaphyseal femur fractures

Objective

To investigate the effect of weight-bearing status on radiographic healing of diaphyseal femur fractures.

Design

Retrospective 1:1 matched cohort study.

Setting

Single-level 1 trauma center.

Participants

One-hundred forty-four (N = 154) patients matched 1:1 in non-weight bearing (NWB) and weight-bearing as tolerated (WBAT) groups.

Intervention

Non-weight bearing following reamed, statically locked intramedullary fixation of diaphyseal femur fracture, generally due to concurrent lower extremity fracture.

Main Outcome Measurement

Postoperative radiographic healing using modified Radiographic Union Scale for Tibia fractures (mRUST) scores.

Results

Groups were well matched on age, sex, race, prevalence of tobacco and alcohol use, diabetes mellitus status, Injury Severity Score, fracture pattern and shaft location, vascular injury, open fracture prevalence, and operative characteristics. Radiographic follow-up was similar between groups (231 vs 228 days, P = .914). At 6 to 8 weeks status post intramedullary fixation, the median mRUST score in the NWB group (9) was lower than that of the WBAT group (10) (mean: 8.4 vs 9.7, P = .004). At 12 to 16 weeks, the median mRUST in the NWB group (10) was again lower than the WBAT group (12) (mean: 9.9 vs 11.7, P = .003). The median number of days to 3 cortices of bridging callous was 85 in the WBAT group, compared with 122 in the NWB group (P = .029). Median time to mRUST scores of 12 (111 vs 162 days, P = .008), 13 (218 vs 278 days, P = .023), and 14 (255 vs 320 days, P = .028) were all longer in the NWB group compared with the WBAT group.

Conclusions

Non-weight bearing after intramedullary fixation of diaphyseal femur fractures delays radiographic healing, with median time to 3 cortices of bridging callous increased from 85 days in WBAT groups to 122 days in NWB groups. These results provide clinicians with an understanding of the expected postoperative course, as well as further support the need to expeditiously advance weight-bearing status.Level of Evidence: IV.

Intramedullary nail holes laser indicator, a non-invasive technique for interlocking of intramedullary nails

Interlocking of intramedullary nails is a challenging procedure in orthopedic trauma surgery. Numerous methods have been described to facilitate this process. But they are exposed patient and surgical team to X-rays or involves trial and error. An accurate and non-invasive method has been provided to easily interlocking intramedullary nails. By transferring a safe visible light inside the nail, a drilling position appears which use to drilling bone toward the nail hole. The wavelength of this light was obtained from ex-vivo spectroscopy on biological tissues which has optimal transmission, reflectance, and absorption properties. Moreover, animal and human experiments were performed to evaluate performance of the proposed system. Ex-vivo performance experiments were performed successfully on two groups of cow and sheep samples. Output parameters were procedure time and drilling quality which there were significant differences between the two groups in procedure time (P < 0.05). But no significant differences were observed in drilling quality (P > 0.05). Moreover, an In-vivo performance experiment was performed successfully on a middle-aged man. To compare the provided method, targeting-arm, and free-hand techniques, two human experiments were performed on a middle-aged and a young man. The results indicate the advantage of the proposed technique in the procedure time (P < 0.05), while the drilling quality is equal to the free-hand technique (P = 0.05). Intramedullary nail holes laser indicator is a safe and accurate method that reduced surgical time and simplifies the process. This new technology makes it easier to interlocking the intramedullary nail which can have good clinical applications.

Antegrade nailing in femoral shaft fracture patients - comparison of outcomes of isolated fractures, multiple fractures and severely injured patients

INTRODUCTION

Femoral shaft fractures in adults are high-energy fractures typically accompanied by additional fractures of the upper and lower extremities and brain, thoracic, or abdominal injuries. Intramedullary nailing enables early ambulation with a few complications, but rates of non-union remain high. Therefore, we aimed to compare bone union after femoral shaft fractures in adults (20-65 years old) depending on the injury severity and presence of multiple fractures.

PATIENTS AND METHODS

This study retrospectively examined 178 patients (145 male and 33 female) who underwent intramedullary nailing for a femoral shaft fracture (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association 32 type) between January 2014 and December 2018 and were followed up for at least 1 year. Patients who underwent intramedullary nailing after the preliminary application of an external fixator were excluded. Patients were divided into groups with isolated femoral shaft fractures (IS group), an injury severity score of ≤14, and multiple fractures of the extremities and the pelvic bone (at least three locations), including a femoral shaft fracture (MU group), and severely injured (injury severity score ≥15) with femoral shaft fractures (SE group). Non-union rate by group and risk factors related to bone union and bone union rate according to time to full weight bearing were analyzed.

RESULTS

In total, 29, 54, and 95 patients were assigned to the IS group, MU group, and SE group, respectively. Non-union was observed in two patients in the IS group (6.9%), six patients in the MU group (11.1%), and 11 patients in the SE group (11.6%). There were no significant differences in the bone union rate, according to multiple fractures (p=0.515) and injury severity score (p=0.561). Additionally, no differences in the bone union rate were observed according to the time to full weight bearing. Depending on open fracture (p=0.004) and fracture severity (p=0.011), the non-union rate showed a difference of up to four times or greater.

CONCLUSIONS

When intramedullary nailing is performed to treat femoral shaft fractures, multiple fractures and severe trauma do not directly affect bone union. However, it should be noted that open fracture and greater fracture severity lead to higher chances of non-union.

Management of Gustilo-Anderson IIIB open tibial fractures in adults-a systematic review

INTRODUCTION

Open tibial fractures are the most common open long bone fracture, despite this, the management of these complex injuries still remains a topic of discussion amongst orthopaedic surgeons.

SOURCES OF DATA

We searched the EMBASE, MEDLINE and Google Scholar and a systematic review of 7500 articles, leaving 23 after exclusion criteria were applied, in order to analyse the management of open tibial fractures.

AREAS OF AGREEMENT AND CONTROVERSY

Infection was noted to be the most significant concern amongst authors, with definitive external fixation having a high rate of superficial pin-site infection and internal fixation having a high deep infection rate.

GROWING POINTS

It is essential to have a combined ortho-plastic approach to the management of these fractures as muscle flaps were the most common form of soft tissue coverage.

AREAS TIMELY FOR DEVELOPING RESEARCH

A national pragmatic trial into the management of open tibial fractures is required looking at fixation methods and soft tissue coverage, with at least a 2-year follow-up in order to ascertain the most appropriate management of these fractures and patient-related outcomes.

Role of open cerclage wiring in patients with comminuted fractures of the femoral shaft treated with intramedullary nails

Introduction

The role of open cerclage wiring in comminuted femoral shaft fracture treatment with intramedullary nails remains unclear. Here, we analyzed the effect of open cerclage wiring and the risk factors for nonunion after interlocking nailing in comminuted femoral shaft fracture treatment. We hypothesized that open cerclage wiring can be applied in patients with severe comminuted femoral shaft fractures without affecting bone healing.

Patients and methods

This retrospective cohort study used data from consecutive patients who underwent interlocking nail fixation of a comminuted femoral shaft fracture between January 1, 2009, and December 31, 2016. First, eligible patients were divided into the wire and no wire groups according to the surgical technique used, and their union rate was recorded. The patients were then divided into the union and nonunion groups, and their perioperative data were analyzed.

Results

In total, 71 comminuted femoral shaft fractures treated with interlocking nail fixation were included: 38 fractures (53.5%) augmented with the open wiring technique and 33 reduced with closed or mini-open techniques without wiring. The wire group demonstrated significant improvements in fracture reduction compared with the no wire group, whereas no significant difference was observed in the union rate between the wire and no wire groups (p = 0.180). Moreover, 46 (65%) of 71 fractures achieved union smoothly, and no significant difference was observed in any perioperative data between the union and nonunion groups.

Discussion

Augmentation with open cerclage wiring is indicated for comminuted femoral shaft fractures treated with intramedullary nails, even when the fragments are large or greatly displaced. Thus, open cerclage wiring can be used for fracture treatment without decreasing the union rate.

Wireless 3D Surgical Navigation and Tracking System With 100μm Accuracy Using Magnetic-Field Gradient-Based Localization

This paper describes a high-resolution 3D navigation and tracking system using magnetic field gradients, that can replace X-Ray fluoroscopy in high-precision surgeries. Monotonically varying magnetic fields in X, Y and Z directions are created in the field-of-view (FOV) to produce magnetic field gradients, which encode each spatial point uniquely. Highly miniaturized, wireless and battery-less devices, capable of measuring their local magnetic field, are designed to sense the gradient field. One such device can be attached to an implant inside the body and another to a surgical tool, such that both can simultaneously measure and communicate the magnetic field at their respective locations to an external receiver. The relative location of the two devices on a real-time display can enable precise surgical navigation without using X-Rays. A prototype device is designed consisting of a micro-chip fabricated in 65nm CMOS technology, a 3D magnetic sensor and an inductor-coil. Planar electromagnetic coils are designed for creating the 3D magnetic field gradients in a 20×20×10 cm³ of scalable FOV. Unambiguous and orientation-independent spatial encoding is achieved by: (i) using the gradient in the total field magnitude instead of only the Z-component; and (ii) using a combination of the gradient fields to correct for the non-linearity and non-monotonicity in X and Y gradients. The resultant X and Y FOV yield ≥90% utilization of their respective coil-span. The system is tested in vitro to demonstrate a localization accuracy of m in 3D, the highest reported to the best of our knowledge.

Biomechanical behavior of retrograde intramedullary nails in distal femoral fractures

Fractures of the distal femur affect three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. Main indications of intramedullary nailing are for supracondylar fractures type A or type C of the AO classification. The main objective of the present work is to analyze, by means of FE simulation, the influence of retrograde nail length, considering different blocking configurations and fracture gaps, on the biomechanical behavior of supracondylar fractures of A type. A three dimensional (3D) finite element model of the femur from 55-year-old male donor was developed, and then a stability analysis was performed for the fixation provided by the retrograde nail at a distal fracture with different fracture gaps: 0.5 mm, 3 mm y 20 mm, respectively. Besides, for each gap, three nail lengths were studied with a general extent (320 mm, 280 mm and 240 mm), considering two transversal screws (M/L) at the distal part and different screw combinations above the fracture. The study was focused on the immediately post-operative stage, without any biological healing process. In view of the obtained results, it has been demonstrated new possibilities of blocking configuration in addition to the usual ones, which allows establishing recommendations for nail design and clinical practice, avoiding excessive stress concentrations both in screws, with the problem of rupture and loss of blocking, and in the contact of nail tip with cortical bone, with the problem of a new stress fracture.

Retrograde entry portal for cephalomedullary nailing in difficult subtrochanteric fractures

An entry point medial to the tip of the greater trochanter is considered optimal for antegrade femur nailing. The deforming forces in a subtrochanteric fracture often make it difficult to establish a perfect entry point during antegrade cephalomedullary nailing. To overcome this problem, we report a simple technique of making a retrograde entry portal for select difficult subtrochanteric fractures. The technique was used in 12 subtrochanteric fractures. Our indications were morbid obesity, revision nailing and atypical fractures. The technique involves creating a nail entry portal through the fracture from distal to proximal taking advantage of the abducted proximal fragment. Fracture reduction and nail insertion then proceeds in a standard manner. Additional reaming of the thick endosteal lateral cortex through the fracture was performed in atypical fractures. Satisfactory fracture reduction was achieved in all patients and 11 out of the 12 fractures united in the series. 1 patient developed an infected nonunion and was considered failure of treatment. The retrograde entry portal is a valuable alternative method that can be considered in nailing of difficult subtrochanteric fractures to establish an ideal entry point and nail trajectory.

Bone Lengthening with a Motorized Intramedullary Nail in 34 Patients with Posttraumatic Limb Length Discrepancies

The Fitbone® motorized nail system has been used to correct limb length discrepancies (LLD) for several years. This study focuses on its application in posttraumatic limb lengthening surgery, its outcome and challenges.

MATERIALS AND METHODS

A prospective, single center study was conducted between 2010 and 2019 in patients treated with motorized lengthening nails. The inclusion criteria were symptomatic LLD of 20 mm or more. An imaging analysis was done using TraumaCad® software (Brainlab AG, Munich, Germany) to compare frontal alignment angles and limb length discrepancy (LLD) on preoperative and latest follow-up radiographs of the lower limbs.

RESULTS

Thirty-four patients were included with a mean age of 28.8 ± 9.7 years, a mean follow-up of 27.8 ± 13 months and a mean hospital stay of 4.4 ± 1.7 days. The mean LLD was 44 ± 18 mm in 29 femoral and 32 ± 8 mm in 4 tibial cases, which was reduced to less than 10 mm in 25/34 (74%) patients. The mean healing index was 84.6 ± 62.5 days/cm for femurs and 92 ± 38.6 days/cm for tibias. The mean time to resume full weight-bearing without walking aids was 226 days ± 133. There was no significant difference between preoperative and final follow-up alignment angles and range of motion. The mechanical lateral distal femoral angle (mLDFA) was corrected in the subgroup of 10 LLD patients with varus deformity of the femur (preoperative 95.7° (±5.0) vs. postoperative 91.5° (±3.4), p = 0.008). According to Paley's classification, there were 14 problems, 10 obstacles and 2 complications.

DISCUSSION

Six instances of locking screw pull out, often requiring reoperation, raise the question of whether a more systematic use of blocking screws that provide greater stability might be indicated. Lack of compliance can lead to poor outcomes, patient selection in posttraumatic LLD patients is therefore important.

CONCLUSION

Limb lengthening with a motorized lengthening nail for posttraumatic LLD is a relatively safe and reliable procedure. Full patient compliance is crucial. In-depth knowledge of lengthening and deformity correction techniques is essential to prevent and manage complications.

Finite element analysis of biomechanical effects of residual varus/valgus malunion after femoral fracture on knee joint

OBJECTIVE

Post-operative femoral shaft fractures are often accompanied by a residual varus/valgus deformity, which can result in osteoarthritis in severe cases. The purpose of this study was to investigate the biomechanical effects of residual varus/valgus deformities after middle and lower femoral fracture on the stress distribution and contact area of knee joint.

METHODS

Thin-slice CT scanning of lower extremities and MRI imaging of knee joints were obtained from a healthy adult male to establish normal lower limb model (neutral position). Then, the models of 3°, 5°, and 10° of varus/valgus were established respectively by modifying middle and lower femur of normal model. To validate the modifying, a patient-specific model, whose BMI was same to former and had 10° of varus deformity of tibia, was built and simulated under the same boundary conditions.

RESULT

The contact area and maximum stress of modified models were similar to those of patient-specific model. The contact area and maximum stress of medial tibial cartilage in normal neutral position were 244.36 mm² and 0.64 MPa, while those of lateral were 196.25 mm² and 0.76 MPa. From 10° of valgus neutral position to 10° of varus, the contact area and maximum stress of medial tibial cartilage increased, and the lateral gradually decreased. The contact area and maximum stress of medial meniscus in normal neutral position were 110.91 mm² and 3.24 MPa, while those of lateral were 135.83 mm² and 3.45 MPa. The maximum stress of medial tibia subchondral bone in normal neutral position was 1.47 MPa, while that of lateral was 0.65 MPa. The variation trend of medial/lateral meniscus and subchondral bone was consistent with that of tibial plateau cartilage in the contact area and maximum stress.

CONCLUSION

This study suggested that varus/valgus deformity of femur had an obvious effect on the contact area and stress distribution of knee joint, providing biomechanical evidence and deepening understanding when performing orthopedic trauma surgery or surgical correction of the already existing varus/valgus deformity.

Application of the multiplanar fracture redactor in the treatment of tibial shaft fractures with intramedullary nails

This prospective study aimed to introduce the application of the multiplanar fracture redactor (MFR) in the treatment of tibial shaft fractures with intramedullary nails (IMNs). From February to June 2018, a total of 18 patients with tibial shaft fractures were recruited. MFR was used to help achieve the reduction of tibial shaft fractures with IMN in all patients. The demographic and fracture characteristics, surgical data, postoperative complications and prognostic indicators of 16 patients were recorded. All operations were performed under closed reduction, excellent radiological and functional outcomes were observed. The average duration of surgery, intraoperative blood loss, intraoperative fluoroscopy times, number of intraoperative assistants, and duration of postoperative hospital stay were 91.2 ± 26.1 min, 95.0 ± 58.3 ml, 19.2 ± 2.3 times, 1 (1-2), and 7.8 ± 2.6 days, respectively. The mean Lysholm Knee Function Score (LKFS), American Orthopaedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS) scores at one year after surgery were 96.8 ± 2.1, 94.8 ± 2.9, and 1 (0-3), respectively. Wound infection, non-union, malunion or complications associated with MFR were not observed in this study. Thus, MFR was a safe and neater method to achieve and maintain the reduction of tibial shaft fractures with IMN.

Pathological fractures of the femur after radiation therapy for soft tissue tumor: a case series of seven patients treated with repeated internal fixation

INTRODUCTION

Pathological femoral fracture (PFF) after radiation therapy (RT) for soft tissue tumor is a debilitating complication with a high rate of nonunion that requires multiple subsequent procedures and hindrance of functional activity. We aimed to evaluate healing rate after repeated internal fixation in a case series of PFF after RT.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients who had PFF after RT and were treated at our center between 2007 and 2018. We analyzed our surgical protocols and fracture healing rate.

INTERPRETATION

We identified and analyzed a total of seven patients (six females and one male) whose mean age at fracture was 58 years. Primary tumors consisted of soft tissue sarcoma (n = 5), melanoma (n = 1), and desmoid tumor (n = 1). All primary tumors were treated with surgical excision and adjuvant RT. The mean follow-up duration after fracture was 33 months (range, 16-58). At the last follow-up, five out of seven fractures had completely healed, and two lesions showed delayed union at 15 and 16 months, respectively. Among the five complete unions, one fracture was healed after the first fixation. The remaining four lesions were treated with second internal fixation due to nonunion/metal failure or delayed union. The mean time to radiologic healing after the last fixation was 6.8 months (range, 5-8).

CONCLUSIONS

Our results suggest that bones within the RT field retain healing capacities, and that repeated internal fixation may be a viable option for the treatment of PFF after RT.

"Ratio of fracture site diameter to isthmus femoral canal diameter" as a predictor of complication following treatment of infra-isthmal femoral shaft fracture with antegrade intramedullary nailing

INTRODUCTION

Fixation of infra-isthmus femoral shaft fracture using antegrade intramedullary (IM) nailing is difficult and is associated with a high complication rate. This study aimed to identify risk factors for complications following this procedure. The ratio of the fracture site diameter to the diameter of the femoral intramedullary canal of the isthmus (FI ratio) was evaluated as a novel parameter to predict complication.

MATERIALS AND METHODS

Patients who underwent antegrade IM nailing for infra-isthmus femoral shaft fracture between January 2008 and December 2018 and had a minimum of 12 months of follow-up were retrospectively reviewed. The primary outcome was occurrence of complication, including non-union, mal-alignment, fixation failure, or progressive loss of reduction. Logistic regression analysis was performed to identify risk factors of complication. The sensitivity and specificity of FI ratio as a predictor of complication was calculated. A receiver operating characteristic (ROC) curve was generated to establish an FI ratio threshold to predict occurrence of complication following antegrade IM nailing.

RESULTS

Sixty-five patients with a mean age of 47.1 years were included. Using univariate logistic regression analysis, comminuted fracture pattern (p=0.026), distance from screws to fracture site (< 3cm) (p=0.002), and higher FI ratio (p=0.001) were associated with complication. Using multivariate logistic regression analysis, FI ratio was identified as an independent risk factor for complication following antegrade IM nailing (p=0.038). ROC curve indicated that FI ratio ≥ 2 had sensitivity and specificity of 0.72 and 0.72, respectively, in predicting complication.

CONCLUSIONS

Our study indicates that wider intramedullary diameter at the fracture site was associated with higher complication rate following antegrade IM nailing in distal infra-isthmal femoral fractures. The FI ratio could be a reliable predictor of complication after antegrade IM nailing for such fracture, and alternative strategies should be considered for patients with higher FI ratio (≥ 2).

Augmented compression in exchange nailing for femoral and tibial non-unions accelerates time to radiographic union

PURPOSE

Exchange nailing is widely used for the management of aseptic femoral and tibial non-union. Compressive forces markedly reduce strain, increasing rate and incidence of union. Additional compressive forces can be applied to the non-union site by using the design features of some modern nailing systems. This study hypothesises that the use of additional compression in exchange nailing results in faster time to union.

METHODS

All femoral and tibial shaft non-unions were identified over a 4-year period between 2014-2018. Intraoperative compression during exchange nailing was either applied or not applied with a dedicated active compression device through the intramedullary nail. An initial 'radiographic union score for tibia' (RUST) score was calculated from preoperative lateral and AP radiographs and compared with the postoperative radiographs at 6-8 weeks. Healing was defined as bridging callus on at least three cortices (RUST > 10).

RESULTS

A total of 119 patients were identified. Following application of exclusion criteria, we analysed data for 19 patients, 10 undergoing exchange nailing with intraoperative compression and 9 without. The pre-exchange RUST score was comparable between the compressed group and standard exchange group with mean of 7.11 versus 7.5 (p = 0.636). At 6-8 weeks post-op, there was a significant difference between the median RUST score in the compressed group vs standard exchange group, 11 compared to 8.39 (p = 0.001).

CONCLUSIONS

Our study shows that time to union was accelerated when additional compression was applied to exchange nailing, resulting in reduced follow-up visits and number of radiographs required.

Does coating an intramedullary nail with polymethylmethacrylate improve mechanical stability at the fracture site?

BACKGROUND

Treatment of tibia diaphyseal fractures with intramedullary nail fixation has proven to be effective. An increasingly popular practice is to coat the nail with bone cement incorporating antibiotics for the purpose of treating and/or preventing infection. To date, the effect of coating on the mechanical performance of the intramedullary nail once implanted is unknown. We hypothesize that cement coating does not change the cross-sectional stiffness of the nail, so that, when fixing tibia diaphyseal fracture with gapping, cement coated intramedullary nail provide stiffness comparable to that of standard conventional uncoated ones.

METHODS

Tests of 4-point bending were conducted to compare the cross-sectional stiffness of uncoated to coated nails. In addition, mechanical tests of compression and torsion on tibia bone phantoms instrumented with coated and uncoated nails were performed, and the proximal-to-distal bone fragment rotations were compared.

FINDINGS

The 4-point bending tests indicated that the cross-sectional stiffness of coated nails was not significantly different from that of the uncoated ones (p-value >0.05). Mechanical tests of compression and torsion corroborated these results by showing no statistical difference in the proximal-to-distal bone rotations attained with uncoated nails when compared to those measured for the coated ones (p-value >0.05).

INTERPRETATION

Cement coating on the nail cannot be relied upon for increased mechanical stiffness of the implant, and should be solely considered as a vehicle for topic delivery of antibiotics.