Computer navigation allows for accurate reduction of femoral fractures

Is mini-open intramedullary nailing an effective intervention for adult femoral diaphyseal fractures in odd hours? A prospective case-control functional outcome and radiation safety study

BACKGROUND

Closed intramedullary (IM) nailing among various modalities is one of the commonest sought out procedure in current practice for management of femoral-diaphyseal fractures (FDF) following trauma. However, it has some limitations like prolonged procedural duration, high radiation exposure and a steep learning curve. Therefore, with limited resources in odd hours and at a high patient turnover center where closed reduction can be a challenge, we adopted a modified mini-open technique which can overcome the limitations of closed reduction technique.

PURPOSE

To compare the closed IM nailing and mini-open technique in FDF in terms of radiation exposure, surgical duration, radiological and functional outcome.

PATIENTS AND METHODS

A total of 100 patients (118 femurs) with FDF (AO 32A1-B2) operated in odd-hours (20:00-06:00 hrs. GMT +5.30) with closed (Group I, n=62) or mini-open (Group II, n=56) IM nailing technique between September 2018 to December 2019 with a minimum follow up of 12 months were included in this study. The functional outcomes were measured using Thoresen scoring system and statistical analysis were performed using paired t-test and χ2 -test.

RESULTS

The overall mean patient age was 33.5 years (18-74 years). The mean surgical duration, c-arm shoots for reduction and radiological union time were 71.5 minutes, 21 shoots and 16 weeks, respectively for group I and 47.5 minutes, 9.4 shoots and 18 weeks for group II. There was significant difference between the two groups in mean surgical duration (p<0.05) and c-arm shoots (p<0.05). However, there was no statistical significant difference between time for union, rate of union, functional results and incidence of superficial or deep infection between the two groups.

CONCLUSION

In conclusion, mini-open technique is a safer alternative in patients with FDF at high-volume centers and in odd-hours when the available resources are limited.

Computer-Assisted Orthopedic and Trauma Surgery

BACKGROUND

There are many ways in which computer-assisted orthopedic and trauma surgery (CAOS) procedures can help surgeons to plan and execute an intervention.

METHODS

This study is based on data derived from a selective search of the literature in the PubMed database, supported by a Google Scholar search.

RESULTS

For most applications the evidence is weak. In no sector did the use of computer-assisted surgery yield any relevant clinical or functional improvement. In trauma surgery, 3D-navigated sacroiliac screw fixation has become clinically established for the treatment of pelvic fractures. One randomized controlled trial showed a reduction in the rate of screw misplacement: 0% with 3D navigation versus 20.4% with the conventional procedure und 16.6% with 2D navigation. Moreover, navigation-assisted pedicle screw stabilization lowers the misplacement rate. In joint replacements, the long-term results showed no difference in respect of clinical/functional scores, the time for which the implant remained in place, or aseptic loosening.

CONCLUSION

Computer-assisted procedures can improve the precision of certain surgical interventions. Particularly in joint replacement and spinal surgery, the research is moving away from navigation in the direction of robotic procedures. Future studies should place greater emphasis on clinical and functional results.

Evaluation of the smartphone for measurement of femoral rotational deformity

BACKGROUND

A novel measurement technique has been designed to assess femoral rotation deformation. The purpose of this study was to evaluate smartphone-aided measurement, including measurement software, intra-observer differences and the occurrence frequency of the unacceptable outliers.

METHODS

Five positions (intact bone, external and internal rotations of 20° and 40° of the distal blocks after dividing the femoral shafts using a saw) were used in each of the five artificial femora. Guide wires were separately inserted into the proximal and distal ends of the model femora with a navigation system and the intersection angles between the guide wires were measured with a smartphone. The values obtained by two measurement software packages (Smart Tools and Super Swiss Army Knife) were compared with that measured on the overlapped computed tomography images.

RESULTS

There were no significant differences between the intersection angles measured by smartphone and that measured on the overlapped images (P = 0.24). The mean absolute difference between pairs of measurements of the two software packages for all guide wire angles was 2.33 ± 2.34°, without statistically significant difference (P = 0.33). There was a significant correlation (r = 0.99) between the first and second (1 week apart) measurements with the same measurement tool. The values of offset capability index of the Smart Tools and the Super Swiss Army Knife measurement tools were 1.62 and 1.13, respectively.

CONCLUSION

Smartphone-aided measurement technique could reliably assess femoral rotation deformation with more accurate angle measurement for software with zero calibration function.

Application of fracture-sustaining reduction frame in closed reduction of femoral shaft fracture

Objectives

This study aims to explore the clinical efficacy of applying a new reduction brace in the closed reduction of femoral shaft fracture.

Methods

A total of 18 patients with femoral shaft fracture, who were admitted to the Bone Trauma Surgery, Second Hospital of Shanxi Medical University, from September 2015 to January 2017, were chosen. A novel reduction brace combined with closed reduction intramedullary nail insertion on the traction table adopted for the orthopedic surgery was taken for the fixation. Then, surgical time, bleeding amount, and postoperational fracture healing time were recorded.

Results

All 18 patients with femoral shaft fracture successfully received closed reduction femoral nail with the application of the novel reduction brace. The follow-up period was 3–18 months, with an average of 12 months, and the femoral shaft fracture was well healed with good recovery of function.

Conclusions

The design of the closed reduction brace of the femoral shaft fracture was reasonable, simple, and convenient to use and has a short learning curve. Furthermore, it led to little trauma to these patients and fully played the advantages of minimally invasive therapy for femoral fractures.

Minimizing Leg Length Discrepancy After Intramedullary Nailing of Comminuted Femoral Shaft Fractures: A Quality Improvement Initiative Using the Scout Computed Tomography Scanogram

OBJECTIVES

To prevent leg length discrepancy (LLD) after locked femoral nailing in patients with comminuted femoral shaft fractures.

DESIGN

Prospective consecutive case series aimed at quality improvement.

SETTING

Level 1 Trauma Center PATIENTS:: Ninety-eight consecutive patients with a comminuted femoral shaft fracture underwent statically locked intramedullary nailing, with a focused attempt at minimizing LLD during surgery.

INTERVENTION

A computed tomography scanogram of both legs was performed on postoperative day 1 to assess for residual LLD. Patients were offered the option to have LLD >1.5 cm corrected before discharge.

MAIN OUTCOME MEASURE

LLD >1.5 cm.

RESULTS

Twenty-one patients (21.4%) were found to have an LLD >1.5 cm. An LLD >1.5 cm occurred in 10/55 (18%) antegrade nail patients and 11/43 (26%) retrograde nail patients (P = 0.27). No difference was noted based on the mechanism of injury, surgeon training and OTA/AO type B versus C injury. Ninety of 98 patients left with <1.5 cm LLD, 13/21 had a correction all to ≤0.6 cm, and 8 decided to accept the LLD and declined early correction.

CONCLUSIONS

No patient left the hospital with an LLD >1.5 cm after locked intramedullary nailing for a comminuted femoral shaft fracture without being informed and the option of early correction. We recommend using a full-length computed tomography scanogram after IM nailing of comminuted femur fractures to prevent iatrogenic LLD.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Radiographic markers for measuring tibial rotation based on CT-reconstructed radiographs: an accuracy and feasibility study

OBJECTIVES

Malreduction in the axial plane (malrotation) following tibial fracture surgery is often undiagnosed. A few clinical and radiographic methods have been proposed for measuring tibial rotation intraoperatively, yet have failed to match the accuracy of computed tomography (CT). The aim of this study was to develop radiographic tools for future intraoperative assessment of the tibial shaft rotation profile.

METHODS

The setting was a laboratory computerized analysis. Twenty lower limb CT scans were used to construct a three-dimensional (3D) model using AMIRA© software. A virtual 3D cylinder was implanted in the posterior condylar line and in the transmalleolar axis. The 3D models were used to simulate four standard knee and ankle plain radiographs. On each radiograph, four landmarks were depicted by two observers and their relation with the cylinder was measured and analyzed for accuracy and reproducibility. A cadaveric lower leg was implanted with two Kirschner wires. A CT scan was performed in addition to 2D fluoroscopy. The simulated radiographs and the fluoroscopy were compared for accuracy.

RESULTS

Measurement of the landmarks showed reliability in most of the knee anteroposterior and ankle mortise radiographs (coefficients of variation < 0.01 and = 0.01) respectively. Cadaveric measurement of the landmarks using real fluoroscopy and simulated radiographs were similar.

CONCLUSIONS

To date, no reliable and common methods have been reported for the evaluation of tibial axial rotation. We propose a model in which simple radiographic landmarks can be used to calculate a 3D coordinate system that accurately assesses the axial rotation angle of the tibial shaft.

Intraoperative Correction of Femoral Rotational Deformity Using a Conventional Navigation System and a Smartphone: A Novel Technique

The intraoperatively rotational control of femoral shaft fractures treated with a closed intramedullary interlocking nailing is a challenging problem. A novel surgical technique that includes respective insertions of guidewires into the proximal and distal femur under the guidance of a 2-dimensional fluoroscopy-based navigation system and the measurements of the intersection angle subtended by the proximal and distal guidewires with the smartphone positional software has been designed to provide intraoperatively quantitative parameters of femoral rotation deformation. The comparison of these parameters with preoperative measurement values of the contralateral intact femur on computed tomography images was used to align the proximal and distal femur fragments based on periaxial rotation. The purpose of this study was to evaluate its clinical suitability. Ten adult patients with femoral shaft fractures were attempted to correct intraoperatively femoral rotational deformity using this novel technique. The additional operation time was 20.04 ± 3.27 minutes. The angle of femoral anteversion was 20.85° ± 4.22°, 38.14° ± 19.07°, and 22.77° ± 3.38° in the contralateral intact and preoperatively and postoperatively injured femur, respectively. The mean absolute difference between both limbs was preoperatively 21.55° ± 10.14° with a statistically significant difference ( P = .005) and postoperatively 3.24° ± 1.69° with no statistically significant difference ( P = .092). Our results showed this novel technique could become an effective tool to correct intraoperatively rotational malalignment of femoral fractures.

Computer-assisted surgery: The use of stored intraoperative images for accurate restoration of femoral length and rotational alignment after fracture

Most femoral fractures are now managed with minimally invasive internal fixation. In the absence of formal exposure of the fracture lines, these procedures make heavy use of C-arm fluoroscopy to allow both fracture reduction and placement of implants, at the expense of measurable radiation exposure to both patient and surgeon. Although this technology has been commercially available for over a decade, it has not yet been widely accepted by the Orthopaedic community.

Preoperative virtual reduction reduces femoral malrotation in the treatment of bilateral femoral shaft fractures

INTRODUCTION

In bilateral femoral shaft fractures, significant malrotation (>15°) occurs in about 40 % of cases after intramedullary nailing. Most of the methods that provide rotational control during surgery are based on a comparison to the intact femur and, thus, not applicable for bilateral fractures. In this study, we evaluated if preoperative virtual reduction can help improving rotational alignment in patients with bilateral femoral shaft fractures.

MATERIALS AND METHODS

Seven patients with bilateral femoral shaft fractures were initially treated with external fixation of both femurs. After obtaining a CT scan of both legs, the fractures were reduced virtually using the software program VoXim®, and the amount and direction of rotational correction were calculated. Subsequently, the patients were treated by antegrade femoral nailing and rotation was corrected to the preoperatively calculated amount.

RESULTS

After external fixation, the mean rotational difference between both legs was 15.0° ± 10.2°. Four out of seven patients had a significant malrotation over 15°. Following virtual reduction, the mean rotational difference between both legs was 2.1° ± 1.2°. After intramedullary nailing, no case of malrotation occurred and the mean rotational difference was 6.1° ± 2.8°.

CONCLUSIONS

Preoperative virtual reduction allows determining the pretraumatic femoral antetorsion and provided useful information for the definitive treatment of bilateral femoral shaft fractures. We believe that this procedure is worth being implemented in the clinical workflow to avoid malrotation after intramedullary nailing.

Radiological outcome and intraoperative evaluation of a computer-navigation system for femoral nailing: a retrospective cohort study

AIM

Intraoperative determinations of femoral antetorsion and leg length during fixation of femoral shaft fractures present a challenge. In femoral shaft fracture fixations, a computer-navigation system has shown promise in determining antetorsion and leg length discrepancies. This retrospective cohort study aimed to determine whether the use of computer navigation during femoral nailing procedures reduced postoperative femoral malrotation and leg length discrepancy, as well as the number of revision cases. We also sought to determine whether radiation exposure time was reduced when computer navigation was used.

MATERIALS AND METHODS

Of 246 patients treated for femoral shaft fractures between 2004 and 2012, we selected those that received postoperative computed tomography for rotation and leg length control. We included 24 patients who received navigation-assisted treatments and 48 who received unassisted treatments, matched for age, sex, and fracture type. All patients were treated by femoral nailing.

RESULTS

The groups showed significant differences in the mean (standard deviation (SD) delay before surgery (navigation-assisted vs. unassisted groups: 8.5 ± 3.2 vs. 5.2 ± 5.8 days; P<0.05) and surgery times (163.7 ± 43.94 vs. 98.3 ± 28.13 min; P<0.001). The groups were significantly different in the mean (SD) radiation exposure time (4.43 ± 1.35 vs. 3.73 ± 1.5 min; P=0.042), and were not significantly different in the postoperative femoral antetorsion difference (8.83 ± 5.52° vs. 12.4 ± 9.2°; P=0.056), or in the postoperative length discrepancy (0.92 ± 0.75 vs. 0.95 ± 0.94 cm; P=0.453). Four (16.7%) navigation-assisted and 15 (31.25%) unassisted surgeries got revision for torsion and/or length corrections.

CONCLUSION

Our results showed that, compared to unassisted femoral surgery, the computer-navigation system did not improve postoperative results or reduce radiation exposure. In the future, improvements in handling and application could facilitate the workflow and may provide better postoperative results. Currently, computer navigation may provide advantages for complicated or sophisticated cases, such as complex three-dimensional deformity corrections.

LEVEL OF EVIDENCE

Level III.

Comparing femoral version after intramedullary nailing performed by trauma-trained and non-trauma trained surgeons: is there a difference?

INTRODUCTION

As with some procedures, trauma fellowship training and greater surgeon experience may result in better outcomes following intramedullary nailing (IMN) of diaphyseal femur fractures. However, surgeons with such training and experience may not always be available to all patients. The purpose of this study is to determine whether trauma training affects the post-operative difference in femoral version (DFV) following IMN.

MATERIALS AND METHODS

Between 2000 and 2009, 417 consecutive patients with diaphyseal femur fractures (AO/OTA 32A-C) were treated via IMN. Inclusion criteria for this study included complete baseline and demographic documentation as well as pre-operative films for fracture classification and post-operative CT scanogram (per institutional protocol) for version and length measurement of both the nailed and uninjured femurs. Exclusion criteria included bilateral injuries, multiple ipsilateral lower extremity fractures, previous injury, and previous deformity. Of the initial 417 subjects, 355 patients met our inclusion criteria. Other data included in our analysis were age, sex, injury mechanism, open vs. closed fracture, daytime vs. nighttime surgery, mechanism of injury, and AO and Winquist classifications. Post-operative femoral version of both lower extremities was measured on CT scanogram by an orthopaedic trauma fellowship trained surgeon. Standard univariate and multivariate analyses were performed to determine statistically significant risk factors for malrotation between the two cohorts.

RESULTS

Overall, 80.3% (288/355) of all fractures were fixed by trauma-trained surgeons. The mean post-operative DFV was 8.7° in these patients, compared to 10.7° in those treated by surgeons of other subspecialties. This difference was not statistically significant when accounting for other factors in a multivariate model (p>0.05). The same statistical trend was true when analyzing outcomes of only the more severe Winquist type III and IV fractures. Additionally, surgeon experience was not significantly predictive of post-operative version for either trauma or non-trauma surgeons (p>0.05 for both).

CONCLUSIONS

Post-operative version or percentage of DFV >15° did not significantly differ following IMN of diaphyseal femur fractures between surgeons with and without trauma fellowship training. However, prospective data that removes the inherent bias that the more complex cases are left for the traumatologists are required before a definitive comparison is made.

Intra-operative assessment of femoral antetorsion using ISO-C 3D: a cadaver study

AIM

The aim of this study was to check the feasibility and accuracy of measuring antetorsion during surgery using a mobile image intensifier (IF) with computed tomography (CT) function (ISO-C 3D; Siemens, Erlangen, Germany) in comparison to a conventional multi-slice CT scanner (LightSpeed QX/I CT; GE Healthcare, VA, USA).

MATERIALS AND METHODS

A total of 10 intact femora with intact soft tissue of five fresh frozen cadavers were used. After fixation on a surgical table, IF CT scans of the hip and knee were performed at both 190° and 120° of scanning rotation. Afterwards, a conventional CT scan was performed. Antetorsion was calculated according to the method of Jend et al. Analysis of variance (ANOVA) and Lin's concordance correlation coefficient (LCC) were used to test the agreement between the three measurement techniques.

RESULTS

There was no significant difference in femoral antetorsion angle measurements between the different techniques (P>0.05). The mean time required to perform a scan using the ISO-C 3D was 9±3 min. The mean time required to measure antetorsion was 8±2 min. We found a high positive correlation between CT-based measurements and measurements performed using both the ISO-C 3D at 190° (LCC=0.99; mean difference=0.02°±1.8°) and the ISO-C 3D at 120° (LCC=0.99; mean difference=0.6°±1.5°), and a high positive correlation was also seen between both ISO-C 3D methods (LCC=0.99; mean difference=0.6°±1.7°).

CONCLUSIONS

Measuring femoral antetorsion using an intra-operative IF with CT function is a feasible and accurate method. This technique could be used when there is doubt about the antetorsion angle in the operated femur and it could help decrease the need for a separate revision surgery.

Computerized navigation for length and rotation control in femoral fractures: a preliminary clinical study

OBJECTIVE

Operative treatment of femoral fractures yields a predictably high union rate, but residual malrotation and leg length discrepancy remain a clinically significant problem. The aim of this study was to determine the safety and efficacy of using computerized navigation in controlling the length and rotation in femoral fracture surgery.

DESIGN

Prospective consecutive case series of 16 skeletally mature patients with femoral fractures undergoing surgical fixation; 14 were fixed with intramedullary nails and 2 with plates.

SETTING

An Academic Level I trauma center.

INTERVENTION

Computerized navigation was used to determine the length and rotation of the operated extremity as compared with the intact healthy contralateral side.

MAIN OUTCOME MEASURE

All patients underwent postoperative computed tomography scanogram for determining the length and rotation.

RESULTS

All fractures healed. Mean rotational difference between the treated and nontreated sides was 3.45 degrees (range, 0-7.7 degrees). Mean length difference between the 2 extremities as calculated by the computed tomography scan was 5.83 mm (range, 0-13 mm). Additional operative time required for computerized navigation was measured in 2 of the cases and totaled ∼30-35 min/case.

CONCLUSION

Computerized navigation was accurate and precise at restoring femoral length and rotation during femoral fracture fixation when the intact contralateral femur was used for reference. Further, large-scale randomized studies are required. Additionally, improvements aimed at decreasing operative time and improving user interface of these systems are recommended.

LEVEL OF EVIDENCE

Therapeutic level IV. See instructions for authors for a complete description of the levels of evidence.

3D atlas-based registration can calculate malalignment of femoral shaft fractures in six degrees of freedom

Objective

This study presents and evaluates a semi-automated algorithm for quantifying malalignment in complex femoral shaft fractures from a single intraoperative cone-beam CT (CBCT) image of the fractured limb.

Methods

CBCT images were acquired of complex comminuted diaphyseal fractures created in 9 cadaveric femora (27 cases). Scans were segmented using intensity-based thresholding, yielding image stacks of the proximal, distal and comminuted bone. Semi-deformable and rigid affine registrations to an intact femur atlas (synthetic or cadaveric-based) were performed to transform the distal fragment to its neutral alignment. Leg length was calculated from the volume of bone within the comminution fragment. The transformations were compared to the physical input malalignments.

Results

Using the synthetic atlas, translations were within 1.71 ± 1.08 mm (medial/lateral) and 2.24 ± 2.11 mm (anterior/posterior). The varus/valgus, flexion/extension and periaxial rotation errors were 3.45 ± 2.6°, 1.86 ± 1.5° and 3.4 ± 2.0°, respectively. The cadaveric-based atlas yielded similar results in medial/lateral and anterior/posterior translation (1.73 ± 1.28 mm and 2.15 ± 2.13 mm, respectively). Varus/valgus, flexion/extension and periaxial rotation errors were 2.3 ± 1.3°, 2.0 ± 1.6° and 3.4 ± 2.0°, respectively. Leg length errors were 1.41 ± 1.01 mm (synthetic) and 1.26 ± 0.94 mm (cadaveric). The cadaveric model demonstrated a small improvement in flexion/extension and the synthetic atlas performed slightly faster (6 min 24 s ± 50 s versus 8 min 42 s ± 2 min 25 s).

Conclusions

This atlas-based algorithm quantified malalignment in complex femoral shaft fractures within clinical tolerances from a single CBCT image of the fractured limb.

Can a semi-automated surface matching and principal axis-based algorithm accurately quantify femoral shaft fracture alignment in six degrees of freedom?

Accurate alignment of femoral shaft fractures treated with intramedullary nailing remains a challenge for orthopaedic surgeons. The aim of this study is to develop and validate a cone-beam CT-based, semi-automated algorithm to quantify the malalignment in six degrees of freedom (6DOF) using a surface matching and principal axes-based approach. Complex comminuted diaphyseal fractures were created in nine cadaveric femora and cone-beam CT images were acquired (27 cases total). Scans were cropped and segmented using intensity-based thresholding, producing superior, inferior and comminution volumes. Cylinders were fit to estimate the long axes of the superior and inferior fragments. The angle and distance between the two cylindrical axes were calculated to determine flexion/extension and varus/valgus angulation and medial/lateral and anterior/posterior translations, respectively. Both surfaces were unwrapped about the cylindrical axes. Three methods of matching the unwrapped surface for determination of periaxial rotation were compared based on minimizing the distance between features. The calculated corrections were compared to the input malalignment conditions. All 6DOF were calculated to within current clinical tolerances for all but two cases. This algorithm yielded accurate quantification of malalignment of femoral shaft fractures for fracture gaps up to 60 mm, based on a single CBCT image of the fractured limb.

Accuracy study of new computer-assisted orthopedic surgery software

PURPOSE

The new computerized system is based on image analysis and designed to aid in orthopedic surgeries by virtual trajectory of the guide wire, intra-operative planning and various measurements. Validation of the accuracy and safety of any computer-aided surgery system is essential before implementing it clinically. We examined the accuracy of guide-wire length and angle measurements and fusion of multiple adjacent images (panoramic view image, PVI(®)) of the new software.

METHODS

This is a 2-part study. Part I: twenty guide wires were drilled to various depths in a synthetic femur model and the results obtained by the software measurements were compared with manual measurements by a caliper and a depth gauge. Part II: a sawbone femur shaft was osteotomized and various inclinations of > 10° to the varus or valgus angles were tested. The manually obtained measurements of angles and lengths were compared to the new computerized system software PVI.

RESULTS

There was a significant positive linear correlation between all groups of the computerized length and the control measurements (r>0.983, p<0.01). There was no significant difference among different distances, angles or positions from the image intensifier. There was a significant positive linear correlation between the angle and length measurement on the PVI and the control measurement (r>0.993, p<0.01).

CONCLUSIONS

The new computerized software has high reliability in performing measurements of length using an aiming, positioning and referring device intra-operatively.

Computer navigation in the reduction and fixation of femoral shaft fractures: a randomized control study

OBJECTIVES

We investigated the accuracy of reduction of intramedullary nailed femoral shaft fractures in human cadavers, comparing conventional and computer navigation techniques.

METHODS

Twenty femoral shaft fractures were created in human cadavers, with segmental defects ranging from 9 to 53 mm in length (Winquist 3-4, AO 32C2). All fractures were fixed with antegrade 9 mm diameter femoral nails on a radiolucent operating table. Five fractures ("Fluoro" group) were fixed with conventional techniques and fifteen fractures ("Nav 1" and "Nav 2" groups) with computer navigation, using fluoroscopic images of the normal femur to correct for length and rotation. Postoperative CT scans compared femoral length and rotation with the normal leg.

RESULTS

Mean leg length discrepancy in the computer navigation groups was smaller, namely, 3.6 mm for Nav 1 (95% CI: 1.072 to 6.128) and 4.2 mm for Nav 2 (95% CI: 0.63 to 7.75) vs. 9.8 mm for Fluoro (95% CI: 6.225 to 13.37) (p<0.023). Mean rotational discrepancies were 8.7° for Nav 1 (95% CI: 4.282 to 13.12) and 5.6° for Nav 2 (95% CI: -0.65 to 11.85) vs. 9.0° for Fluoro (95% CI: 2.752 to 15.25) (p=0.650).

CONCLUSIONS

Computer navigation significantly improves the accuracy of femoral shaft fracture fixation with regard to leg length, but not rotational deformity.

Navigation in femoral-shaft fractures--from lab tests to clinical routine

INTRODUCTION

This study evaluates the use of a navigation system (BrainLAB, Feldkirchen, Germany) to intra-operatively check for correct length, axis and rotation in intramedullary nailing of femoral-shaft fractures in an experimental setting and in clinical routine.

MATERIALS AND METHODS

We tested the navigation system in two experimental settings before introducing it into clinical routine. In the first experiment, 10 osteotomised model femora were fixed with intramedullary nails by using a navigation system. The goal was a locking fixation in predefined values for length and rotation. In the second experiment, eight examiners assessed values for rotation and length of one femur 10 times to examine the accuracy and reproducibility of that determination. Following this, we navigated 40 femoral nailing procedures in our department. Preoperatively, we assessed values of femur geometry on the contralateral side in a computed tomography (CT) scan and reproduced these values intra-operatively on the fractured side, guided by the navigation system. During the intervention, we recorded the length of the procedure steps and the fluoroscopy time. We verified the intra-operative values achieved with the navigation system in a postoperative CT scan and documented differences in rotation and length. After the assessment, we analysed the data for different findings on femur geometry, fluoroscopy time and procedure duration.

RESULTS

The experimental evaluation showed a range of ±5° for anteversion differences and ±2.3 mm for length differences. We estimated this accuracy as sufficient to use the system in clinical routine. The navigation system was used for 40 fracture fixations. All our criteria for restoring femoral geometry could be achieved by navigation guidance in these procedures. Setting up the system took on average 33±11.5 min. An additional fluoroscopy time of 36±22 s was needed to acquire the reference X-rays and to verify pin placement. The differences between anteversion values assessed in intra-operative planning steps on the navigation system and values assessed with a postoperative CT were on average 5.4±3.5°, whilst femur length differed on average by 4±4 mm.

DISCUSSION

Many authors judge intra-operative control of anteversion in femoral-shaft fracture fixation as problematic. Neither our experimental navigation assessment nor our clinical navigated evaluation showed relevant anteversion differences to a postoperative CT assessment of femur geometry. After initial training, guidance by a navigation system achieves consistent results in a clinical situation.

CONCLUSIONS

The use of a navigation system to align axis, length and rotation led to a secure way of avoiding any relevant malalignment in complex femur-shaft fractures whilst exposing patients to an acceptable amount of additional procedure sequences. Malalignment can be avoided by using a navigation system in the operative treatment of femoral-shaft fractures and may be integrated into clinical routine in specialised centres.

Locked intramedullary femoral nailing without fracture table or image intensifier

The present retrospective study aims to evaluate the outcome in 41 patients of femoral shaft fractures, who had closed intramedullary nailing in lateral decubitus position without fracture table or image intensifier. Mean age was 33.2 (range, 18-70) years. The cannulated reamer in proximal fragment (as intramedullary joystick) and Schanz screw in the distal fragment (as percutaneous joystick) were simultaneously used to assist closed reduction of the fracture without the use of image intensifier. Closed reduction was successful in 38 patients. Open reduction was required in 3 patients. Schanz screw was used for closed reduction in 12 patients. Average number of intra-operative radiographic exposures was 4.4. Two patients had exchange nailing using large diameter nails. One patient had nonunion. Angular and rotatory malalignments were observed in seven patients. We are of the opinion that the present technique is a safe and reliable alternative to achieve closed locked intramedullary nailing and is best suited to stable, less comminuted (Winquist-Hansen types I and II) diaphyseal fractures of the femur.

Femoral malrotation following intramedullary nailing in bilateral femoral shaft fractures

INTRODUCTION

This study was designed to evaluate the incidence of femoral malrotation in bilateral femoral shaft fractures.

MATERIALS AND METHODS

All closed bilateral femoral shaft fractures in patients aged 18 or over treated between April 2000 and December 2009 were included in the current study. All patients received a postoperative CT-scan to estimate femoral antetorsion and leg length. All bilateral fractures were treated with intramedullary nailing on a radiolucent table. Retrospectively, all patients were analyzed according to the following parameters: (1) femoral antetorsion of both limbs and antetorsion difference in degrees, (2) femoral length discrepancy (cm), (3) incidence of femoral malrotation >15°, (4) revision rate due to femoral malrotation.

RESULTS

A total of 24 patients (11 [45.8%] female; 13 [52.8%] male) with bilateral femoral shaft fractures were included in this study of average age 38 years (median 38 years, range 18-74 years). Clinically relevant malrotation (greater than 15°) was found in 10 cases (41.2%), whereas in 4 cases (40%) a revision surgery was required.

DISCUSSION

Bilateral femoral shaft fractures are associated with a high incidence of clinically relevant femoral malrotation over 15°. Measurement of intraoperative femoral antetorsion in bilateral femoral shaft fractures is quite difficult and currently only feasible postoperatively.

Simultaneous use of cannulated reamer and schanz screw for closed intramedullary femoral nailing

Introduction. Closed reduction is a critical component of the intramedullary nailing and at times can be difficult and technically challenging resulting in increased operative time. Fluoroscopy is used extensively to achieve closed reduction which increases the intra-operative radiation exposure. Materials and Methods. Sixty patients with femoral diaphyseal fractures treated by locked intramedullary nailing were randomized in two groups. In group I, fracture reduction was performed under fluoroscopy with a cannulated reamer in the proximal fragment or with simultaneous use of a cannulated reamer in the proximal fragment and a Schanz screw in the distal fragment. Patients in group II had fracture reduction under fluoroscopy alone. Results. Closed reduction was achieved in 29 patients in group I and 25 patients in group II. The guide wire insertion time, time for nail insertion and its distal locking, total operative time, and total fluoroscopic time were 26.57, 27.93, 68.03, and 0.19 minutes in group I, compared with 30.87, 27.83, 69.93, and 0.24 minutes in group II, respectively. The average number of images taken to achieve guide wire insertion, for nail insertion and its locking and for the complete procedure in group I, respectively, was 12.33, 25.27, and 37.6 compared with 22.1, 26.17, and 48.27, respectively, in group II. Conclusion. The use of cannulated reamer in proximal fragment as intramedullary joystick and Schanz screw and in the distal fragment as percutaneous joystick facilitates closed reduction of the fracture during closed intramedullary femoral nailing with statistically significant reduction in guide wire insertion time and radiation exposure.

Computer assisted LISS plate placement: an in vitro study

A laboratory study was conducted to compare the accuracy with which a LISS plate could be placed on the distal metaphysis of a model femur using both a fluoroscopy-based computer assisted technique and the conventional fluoroscopic technique. A significant difference was found between outcomes with the two approaches with respect to the maximum distance from the plate to the diaphysis of the bone, but there was no significant difference in the maximum distance to the condylar area. There was also no difference with respect to the number of holes that required re-drilling for adjustment of the plate placement or screws with poor purchase in bone. There were, however, significant differences between the two techniques in terms of duration of the procedure and radiation exposure.

Computer-assisted antetorsion control prevents malrotation in femoral nailing: an experimental study and preliminary clinical case series

MATERIALS AND METHODS

The effect of fluoroscopy-based navigation for femoral fracture reduction on the prevention of malrotation was examined in an experimental setting followed by a first case series. Eleven cadaver femurs were used. All femurs were reduced by closed methods. An optoelectronic navigation system was utilized to check for fragment reduction and alignment. Fluoroscopic control without navigation was used as the control group. The Six Sigma Analysis [offset capability index (C (pk)) = 1.3] was used to compare the probability of outliers of more than 15 degrees . In the clinical case series the same navigation tool was used in ten non-consecutive patients with femoral fractures. Torsional differences between both legs were measured postoperatively by CT scan.

RESULTS

The highest malrotation in the navigated group was 7.0 degrees for the cadaver testings, while two femurs in the control group showed a difference of more than 10 degrees (10.3 degrees , 17.4 degrees). Only the navigated group showed a sufficient offset capability index (C (pk-navigated) = 1.83; C (pk-conventional) = 0.59). In the clinical series nine femurs were successfully reduced by navigation control. The average malrotation was 6.6 degrees . No patient had a torsional difference of more than 10 degrees.

CONCLUSION

Navigated femoral nailing reduces the risk for outliers of postoperative torsional differences and might avoid revision surgery for malrotation.

LEVEL OF EVIDENCE

IV.

Indications and limitations of locked plating

The goal of fracture fixation is to achieve bone healing and restore the function of the injured limb in the shortest possible time without compromising safety. Newer technologies such as the locking compression plate (LCP) and its derivatives are valuable additions to the orthopaedic traumatologist's armamentarium. As with any emerging technology, the indications will be extended until a threshold is reached and the limitations of the technology are seen. It is vital that surgeons involved in fracture care are aware of when locked plating is superior to other methods and also when they should use another treatment modality. This paper reviews the use of locked plating as a fixation method. Five topics covered in this review are: a historical perspective on locked plating, general indications, specific modes and techniques, patterns of failure, and an anatomical overview of current indications for locked plating.

Navigated femoral anteversion measurements: general precision and registration options

INTRODUCTION

Intraoperative reduction of femoral fractures can result in rotational malalignment. Navigation modules allow fluoroscopy-based femoral anteversion (AV) measurements; however, their clinical feasibility has not been fully evaluated. An important technical consideration when obtaining navigated femoral rotational alignment is the necessity for orthogonal navigated fluoroscopic images.

METHODS

The current investigators hypothesized that there would be a critical imaging angle between the fluoroscopic images which optimized the acquisition of accurate rotational measurements. Following initial testing in plastic femora, 14 intact human cadaveric femora were subjected to CT and navigated fluoroscopic assessment of AV. The navigated registration process included the following test series: Standard perpendicular AP and lateral imaging at a 90 degrees angle; planar rotation of the lateral fluoroscopy position perpendicular to the axis of femoral neck and angled to the AP position at 75 degrees, 60 degrees, and 50 degrees; inlet and outlet imaging of the axis of the femoral neck at angles of 10 degrees, 20 degrees, and 30 degrees. For all setups, the difference between the AV angle of the navigation system and the CT-measured angle was calculated.

RESULTS

Results revealed no relevant differences between CT and navigated determination of plastic femora (1.5 degrees). No significant deviations of cadaver femora with 90 degrees angle imaging (mean 2.00 degrees, range 0.00 degrees-4.33 degrees), 75 degrees angle imaging (mean 1.95 degrees, range 0.00 degrees-3.33 degrees) and 60 degrees imaging (mean 2.00 degrees, range 0.00 degrees-3.33 degrees) were found. However, significant deviations were found for the navigated 50 degrees angled imaging technique (mean 5.02 degrees, range 2.33 degrees-7.67 degrees).

CONCLUSION

These data demonstrated that the femoral AV angle can be calculated accurately by using two navigated fluoroscopic images when a minimum angle of 60 degrees is utilized between the angled fluoroscopic images for the registration process. A difference of <60 degrees does not allow for accurate navigated measurements.

Navigated long-bone fracture reduction

The first computer-assisted orthopaedic trauma procedures were limited to navigated drill-guide applications, in which the computer was used to predict the trajectory of the drill guide relative to stored radiographic images. By 2003, software for fracture reduction was commercially available. The ability to perform a minimally invasive fracture reduction with the aid of stored images, combined with navigated insertion of internal fixation, has long been considered the highest achievement in image-guided fracture surgery. It is now possible to apply computer-assisted techniques to all fractures that have traditionally been treated with the aid of intraoperative fluoroscopic control. Less-invasive fixation of long-bone fractures is often complicated by malrotation or shortening of the injured extremity, sometimes requiring reoperation. Recent developments in computer-assisted surgery now allow the orthopaedic surgeon to precisely match the anatomy of the injured extremity to that of the uninjured limb with respect to length and rotational alignment. This is particularly important in comminuted fractures, for which there are no anatomic clues to guide accurate reduction, and in the correction of malreduced fractures. Although computer-assisted technology is now readily available, it has not yet found widespread acceptance in the orthopaedic trauma community. New software workflows (i.e., the step-by-step progression through various screens in the software program during a computer-guided procedure) specific to individual procedures and implants may hasten adoption of these techniques.

Navigated femoral nailing using noninvasive registration of the contralateral intact femur to restore anteversion. Technique and clinical use

The difficulty in assessing femoral rotation during intramedullary nailing is well-established. Navigation systems allow the surgeon to detect and set the version of the injured leg at the desired angle. We report the first cases of navigated femoral nailing using noninvasive registration of the contralateral uninjured leg to determine the patient's anatomy. This allows the desired femoral rotation, which is that of the healthy femur, to be statically locked to precisely match the contralateral limb.