Femoral torsion after interlocked nailing of unstable femoral fractures

Prevention of inaccurate targeting of proximal screws during reconstruction femoral nailing

PURPOSE

The purpose of this study was to identify the underlying cause by simulating the forces involved in a controlled laboratory setting, and then to illustrate some intraoperative tips on how to detect this malalignment and suggest solutions prevent this intraoperative complication.

METHODS

The Expert Asian Femoral Nail (A2FN) and Proximal Femoral Nail Antirotation (PFNA) reconstruction nail systems were evaluated to compare the characteristics of each nailing system and their reactions to soft tissue tension at the time of proximal reconstruction screw placement. Soft tissue tension was simulated by placing a fulcrum under the distal drill sleeve and exerting a load on the targeting device via the addition of weights. The occurrence and degree of guide malalignment were determined while gradually increasing the weight.

RESULTS

When soft tissue tension was simulated on the drill/guide sleeve of the A2FN, the drill sleeve deviated from the proximal screw hole proportionally to the weight applied and the K-wire guide passed outside of the nail at a weight of 7 kg. However, the drill sleeve of the PFNA was aligned exactly to the center of nail axis and the K-wire passed cleanly through the proximal locking hole regardless of weight applied.

CONCLUSIONS

Inaccurate guidance of the screw-targeting device can be caused by soft tissue tension. Thus, the authors recommend that careful attention be placed on minimizing soft tissue tension during proximal screw placement while using the targeting device of the A2FN system.

[Antegrade femoral intramedullary nailing in a lateral position]

BACKGROUND

Intramedullary nailing is the gold standard for the treatment of femoral shaft fractures; however, rotational malalignment remains a common complication. The patient can be positioned on the fracture table in a supine position or alternatively in the lateral decubitus position without any traction.

OBJECTIVE

The aim of this article is to describe an effective method to control intraoperative torsion of the femur.

METHOD

The surgical technique described in this article is the standard procedure for femoral shaft fractures and subtrochanteric fractures in this level 1 trauma center. The patient is positioned in a lateral position on a radiolucent table with free draping of the injured leg. Using the C-arm, reduction can be performed with this technique with precise placing of the nails and torsion can be exactly adjusted and controlled with the aid of the femoral neck axis, the distal locking holes and both parallel femoral condyles.

RESULTS

The described technique represents an effective method for the intraoperative control of femoral torsion. With an acceptable and most probably clinically irrelevant bias, this technique is able to avoid significant rotational malalignment. It does not prolong the operative procedure and does not require additional navigation settings. It has also been shown to be helpful in the treatment of subtrochanteric fractures.

CONCLUSION

The surgical technique of anterograde intramedullary nailing using the lateral decubitus position without any traction device and free draping of the injured leg represents a safe and reliable treatment concept and offers logistical advantages compared to the supine position of the patient on a fracture table. Together with other described methods of intraoperative torsional control of femoral fractures, the radiological technique described in this study is an easily applicable and safe method, which needs to be confirmed in clinical studies.

Does MIPO of fractures of the distal femur result in more rotational malalignment than ORIF? A retrospective study

PURPOSE

Intraoperative control of rotational malalignment poses a big challenge for surgeons when using modern MIPO (minimally invasive plate osteosynthesis) techniques. We hypothesized that distal femoral fractures treated with MIPO technique are more often fixed in malrotation than those treated with open reduction internal fixation (ORIF).

METHODS

In this retrospective study, we identified 20 patients who met the inclusion criteria and agreed to take part in the study. In ten patients MIPO was applied, in the other ten ORIF was used. Mean age was 44.8 (19-71 years). Functional status was assessed using clinical scores (Harris Hip Score, WOMAC Hip, KS Score, WOMAC Knee, Kujala Score). Rotational alignment was assessed with magnetic resonance imaging and compared to the opposite leg.

RESULTS

We discovered a significant difference in the mean rotational difference between the MIPO group (14.3°) and the ORIF group (5.2°). Functionally, patients in the ORIF group outperformed patients in the MIPO group in all clinical scoring systems although no one proved to be statistically significant. MIPO technique was associated with significantly more rotational malalignment compared to ORIF in distal femur fracture fixation. However, implant failure and nonunion was more common in the ORIF group, with a revision rate of 3 versus 1 in the ORIF group. Clinical scoring did not significantly different between both groups.

CONCLUSION

Taking into account the undisputable advantages of minimally invasive surgery, improved teaching of methods to avoid malrotation as well as regular postoperative investigations to detect any malrotation should be advocated.

Torsional malalignment, how much significant in the trochanteric fractures?

OBJECTIVES

The rotational alignment is definitely important in the long bones such as tibias and femurs. We also predict the importance of rotational alignment in the trochanteric fractures. So we measured torsional malalignment in trochanteric fracture and anlaysed their risk factors and their clinical significance.

METHODS

A total of 109 inpatients who had undergone internal fixation following trochanteric fracture and a postoperative pelvic CT scan between 2008 and 2013, with at least one year follow-up, were selected. Factors that affect torsional malalignment, such as age, gender, fracture stability, injured area, operative time, time of surgery after admission, and ASA status, were investigated. Factors that affect the patients' clinical results in malrotation, including ambulation time after surgery, postoperative complication rates, pain assessment of VAS one year postoperatively and Koval score, were also investigated.

RESULTS

Of the 109 subjects, torsional malalignment was observed in 28 (25.7%) subjects with a mean torsional malalignment angle of 20.7° (range: -31.2° to 27.1°). Torsional malalignment risk factors were fracture stability (p=0.021) and operative time (p=0.043). In terms of the time to ambulation after surgery, the postoperative complication rates, and the VAS and Koval scores at one year postoperatively, no statistically significant difference was observed between the torsional malalignment patients and the non-deformity patients.

CONCLUSIONS

In this study, 25.7% of the patients who had undergone internal fixation following trochanteric fracture experienced torsional malalignment. Major factors of the torsional malalignment were an unstable fracture and the consequent delay in the operative time. But the torsional malalignment was deemed to have no effect on clinical results.

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.

Important tips and numbers on using the cortical step and diameter difference sign in assessing femoral rotation--should we abandon the technique?

Rotational malalignment during femoral nailing is common despite having various intraoperative assessment methods. The cortical step sign and diameter difference sign (CSSDDS) is commonly used because of convenience, yet it lack proper scientific scrutiny and is thought to be error prone. Using a software algorithm, cross-sectional dimensions were obtained from CT scans of 22 intact adult femurs at the proximal, mid and distal diaphysis. With multiple simulated scenarios the sensitivity of CSSDDS was comprehensively determined at all possible C-arm positions. At rotation, cortical width changed most significantly around the thick linea aspera and femoral diameter changed most significantly at the sagittal plane. At 15 degrees of rotation and with the linea aspera in view, CSSDDS thresholds of 0.3mm, 0.6mm and 1mm had sensitivities of 98.8%, 93.1% and 73.8%. With the linea aspera masked behind the femur and out of view, the sensitivities significantly deteriorated to 96.4%, 77.1% and 44.1% respectively. CSSDDS is sufficiently sensitive only when strict rules are followed. It is imperative that the operator position the image intensifier in lateral view under proper magnification so that steps of less than 0.6mm around the linea aspera may be appreciated.

Patient positioning on the operative table for more accurate reduction during elastic stable intramedullary nailing of the femur: a technical note

Elastic stable intramedullary nailing is currently considered a clinical practice standard for the treatment of femoral fractures in children in the age-appropriate group. Malreduction, particularly in rotation, due to the closed reduction technique has been reported. We describe a new technique of positioning on a standard operating table that permits better control of rotational alignment during femoral elastic stable intramedullary nailing.

Intramedullary nailing of diaphyseal femur fractures secondary to gunshot wounds: predictors of postoperative malrotation

OBJECTIVES

The purpose of this study was to determine significant factors that may impact the postoperative differences in femoral version (DFV) and differences in femoral length (DFL) between the fixed and uninjured sides after intramedullary nailing (IMN) secondary to gunshot wounds.

DESIGN

Retrospective data registry study.

SETTING

Academic level I trauma center.

PATIENTS

Over a 10-year period, 417 patients underwent IMN of a diaphyseal femur fracture (OTA/AO 32A-C). Of these, 57 patients sustained fractures caused by gunshots and had a postoperative computed tomographic scanogram.

MAIN OUTCOME MEASURES

DFV and DFL. The effect of the following variables on DFV and DFL were determined through univariate and stepwise multivariate regression analyses: age, sex, body mass index, trauma fellowship-trained versus nontrauma surgeon, daytime versus nighttime surgery, antegrade versus retrograde nail insertion, use of traction, type of operating table, and AO and Winquist classifications.

RESULTS

The mean postoperative DFV for all patients was 8.62 degrees (±6.67 degrees). Postoperative DFV greater than 15 degrees was found in 12.3% of all patients. After IMN, no significant differences in DFV were found with increasing complexity of AO/OTA or Winquist fracture classification. None of the aforementioned independent variables were significantly predictive of postoperative DFV in univariate or multivariate analyses. The mean postoperative DFL for all patients was 5.25 mm (±4.36 mm). In a multivariate model, classification as Winquist type 3 or 4 was weakly (adjusted R = 0.075) but significantly predictive of less DFL than categorization as type 1 or 2 (P = 0.027).

CONCLUSIONS

Although gunshot-associated femur fractures may present surgical challenges for treatment through IMN, acceptable femoral rotation and length are obtainable regardless of the fracture complexity or a variety of demographic and surgically-related variables.

LEVEL OF EVIDENCE

Prognostic level II.

Rigid Intramedullary Nailing of Femoral Shaft Fractures in Skeletally Immature Patients Using a Lateral Trochanteric Entry Portal

Introduction

We describe rigid intramedullary nailing using a trochanteric entry for internal fixation of femoral shaft fractures in older children and adolescents.

Step 1 Preparation Prior to Incision

Appropriate preparation prior to the operation is key to minimizing intraoperative and postoperative complications.

Step 2 Perform Incision and Exposure

A well-positioned incision will facilitate and reduce difficulty with ideal guidewire placement.

Step 3 Place and Overream the Guide Pin

Ensure that the guide pin is properly positioned on the greater trochanter, while avoiding the piriformis fossa.

Step 4 Place the Guidewire and Reduce the Fracture

Prepare the definitive guidewire. Insert the guidewire into the proximal fragment via the trochanteric portal. While maintaining the fracture reduction, advance the guidewire into the distal fragment.

Step 5 Measure Nail Length and Begin Overreaming

Pay careful attention to the amount of reaming as well as distraction across the fracture site to provide the best fit for the nail.

Step 6 Insert the Nail

Be sure to maintain the reduction while advancing the nail across the fracture site. Reconfirm that traction has been reduced to avoid distraction at the fracture site.

Step 7 Insert Proximal and Distal Interlocks

Use the interlocking screws to secure the proper rotational alignment.

Step 8 Make Final Images and Close the Wound

Confirm the reduction and adequate fixation before closure.

Results

In our original study, a cohort of 246 femoral shaft fractures among 241 skeletally immature patients treated with trochanteric entry rigid intramedullary nailing was retrospectively reviewed.IndicationsContraindicationsPitfalls & Challenges.

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.

Femoral bow predicts postoperative malalignment in revision total knee arthroplasty

Diaphyseal bowing may compromise axial alignment in revision total knee arthroplasty (TKA). 277 patients undergoing revision TKA were evaluated for coronal bowing and hip-knee-ankle (HKA) axis. The mean femoral bow was 1.52° ± 0.18° varus (-10.1° to +8.4°). The mean tibial bow was 1.25° ± 0.13° valgus (-5.9° to +10°). HKA axis averaged 3.08° ± 0.35° varus preoperatively compared to 0.86° ± 0.25° varus postoperatively. Inter-rater and intra-rater reliability was high. Femoral bow greater than 4° significantly correlated with postoperative HKA axis malalignment (r = 0.402, P = 0.008). 39.7% of patients deviated 3° or greater from a neutral mechanical axis with a significant difference in femoral bow (0.94° ± 0.31°, P = 0.003). Diaphyseal bowing clearly has an important effect on postoperative limb alignment in revision TKA.

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.

Femoral malrotation after intramedullary nailing in obese versus non-obese patients

OBJECTIVE

Intramedullary nailing (IMN) of obese patients with femoral fractures can be difficult due to soft tissue considerations and overall body habitus. Complications including malrotation can occur and have significant impact on postoperative function. The purpose of this study was to evaluate femoral rotation after intramedullary nailing of obese and non-obese patients to see if there was a difference in rotation, complications and any risk factors for malrotation.

MATERIALS AND METHODS

Between 2000 and 2009, 417 consecutive patients with femur fractures treated with IM nail at Level I trauma and tertiary referral center. Of these, 335 with postoperative computed tomography (CT) scanogram of the bilateral lower extremities were included in this study. Baseline demographic, perioperative and postoperative femoral version calculations were included in the dataset. Statistical analysis included chi-squared test for categorical data, t-test for continuous data, and univariate and multivariate regression analysis. Significance was set at p<0.05.

RESULTS

Of the 417 patients with femur fractures between 2000 and 2009, 335 met criteria for this study. There were 111 patients with a BMI <25, 129 with BMI 25-29.9, and 95 patients with a BMI >30. When BMI was categorised into 3 groups (<25, 25-29.9, or 30+), none of these groups were predictive of version in univariate or multivariate regressions. Among only obese patients (BMI 30+), BMI of 35+ was not a significant predictor of version when compared to BMI 30-34.9. There were no significant differences in femoral version based on entry point (antegrade vs. retrograde) in any BMI category. There were also no significant difference between groups of patients with a DFV of >15̊ (p=0.212).

CONCLUSIONS

Based on this study, BMI did not have an effect on postoperative difference in femoral version. In fact, in our multivariate regression analysis, BMI of over 30 was actually predictive of significantly lower difference in femoral version. While other studies have documented the intraoperative difficulties encountered with obese patients with femur fractures, the outcome of femoral rotation is not affected by an increasing BMI.

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.

Use of inherent anteversion of an intramedullary nail to avoid malrotation in femur fractures

Rotational malalignment after intramedullary (IM) nailing of femoral fractures remains a significant problem. A technique using intraoperative fluoroscopy and the anteversion inherent to the IM nail for obtaining appropriate femoral rotational alignment is presented. The technique is advocated as a simple alternative to more complex methods for estimation of femoral anteversion during placement of femoral IM nails. This method is simple and requires intraoperative fluoroscopy on the injured extremity alone. It reliably sets the femoral anteversion within a normal physiologic range with minimal additional intraoperative steps and without preoperative measurements.

The cortical step sign fails to prevent malrotation of a nailed femoral shaft fracture: a case report

Intramedullary nailing has become the treatment of choice for diaphyseal femur fractures. Malrotation is a well-recognized complication of femoral nailing. Various techniques including the cortical step sign (CSS) have been described to minimize iatrogenic rotational deformity during femoral nailing. We present a case in which the use of the CSS resulted in a clinically significant malrotation requiring revision.

Impact of specialty and level of training on CT measurement of femoral version: an interobserver agreement analysis

BACKGROUND

To determine the interobserver agreement on femoral version measurements between an orthopedic attending, orthopedic senior and junior residents, and an attending radiologist.

MATERIALS AND METHODS

Postoperative computed tomography (CT) scanograms of 267 patients who underwent femoral intramedullary (IM) nailing with corresponding radiology attending reads for femoral version were collected and de-identified. Femoral version measurements performed by a trauma fellowship-trained attending orthopedic surgeon (ORTHO), a senior orthopedic resident (PGY4), a junior orthopedic resident (PGY1), and a musculoskeletal fellowship-trained attending radiologist (RADS) were compared via Pearson's interclass correlation coefficient to assess interobserver level of agreement.

RESULTS

Version measurements provided by the two attending physicians exhibited the highest level of agreement (r = 0.661, p < 0.01). The orthopedic attending and the senior resident had the next highest level of agreement (r = 0.543, p < 0.01). The first-year orthopedic resident had the weakest agreement across the board: with the orthopedic attending, the radiology attending, and the senior resident.

CONCLUSION

Regardless of specialty, experience and higher levels of training produce stronger agreement when measuring femoral version. Residents in training, especially those who are junior, produce weak agreement when compared to their senior colleagues.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Rotational malalignment after closed intramedullary nailing of femoral shaft fractures and its influence on daily life

BACKGROUND

Any intraoperative rotational malalignment during intramedullary nailing (IMN) of femoral shaft fractures will become permanent. We hypothesized that rotational malalignment of the femur and its compensatory biomechanics may induce problems in the hip, knee, patellofemoral and ankle joints. We purposed to clarify the influence of a femoral rotational malalignment of ≥10° on daily activities.

METHODS

Twenty-four femoral shaft fracture patients treated with closed antegrade IMN were included. At last follow-up, to reveal any rotational malalignment, computerized tomography (CT) scans of both femurs (injured and uninjured sides) were examined. The patient groups with or without CT-detected true rotational malalignment ≥10° were compared with respect to the activity scores.

RESULTS

Ten of the 24 patients (41.7%) had a CT-detected true rotational malalignment of ≥10° compared with the unaffected side. The AOFAS scores were 100.00 for all of the patients. LKS, WOMAC knee, and WOMAC hip scores were significantly decreased in the patients with rotational malalignment compared to those without. Patients without rotational malalignment tolerated climbing stairs significantly better than those with rotational malalignment. Patients who could not tolerate climbing stairs were consistently complaining of anterior knee pain.

CONCLUSIONS

A femoral rotational malalignment of ≥10° is symptomatic for the patients, and the hip, knee, and patellofemoral joints were affected. Because of the possibly altered joint loadings and biomechanics, these could render patients prone to degenerative joint disease. In addition, due to the high rates of rotational malalignment after femoral shaft fracture and consequent malpractice claims, it is important for surgeons to be more aware of rotational alignment during surgery.

Surgical technique: supine patient position with the contralateral leg elevated for femoral intramedullary nailing

BACKGROUND

Intramedullary nailing can be performed with a fracture table or manual traction. Manual traction can be applied with the patient in either the supine or lateral decubitus (LD) position. However, in either of these positions, the reduction can be difficult because the fractured extremity is not positioned parallel to the floor and the contralateral leg on the operating room table overlaps the fractured limb while the fractured extremity is in full adduction. Therefore fluoroscopy time may be increased. Accordingly, we developed a technique with the patient supine and the contralateral leg elevated (SCLE).

DESCRIPTION OF TECHNIQUE

We performed anterograde femoral intramedullary nailing with the patient in the supine position with the contralateral leg elevated to allow easy nail entry, reduction, and locking. In this position, the uninjured leg was placed on the leg holder in a semilithotomy position to allow full hip adduction.

METHODS

We retrospectively reviewed 63 patients treated with intramedullary nailing: 30 with the SCLE position (mean age, 38 years; 30% female) and 33 with the LD position (mean age, 37 years; 36% female). From the medical records we extracted demographic information, fracture pattern, intramedullary nail diameter, duration of fluoroscopy and operation, and complications. At the last visit, extremity lengths, rotation, and alignment were determined. Minimum followup was 46 months (mean, 46 months; range, 20-72 months).

RESULTS

The mean durations of surgery and fluoroscopy were shorter for the SCLE group than the LD group: 98 versus 108 minutes and 3.4 versus 3.8 minutes, respectively. The open reduction rate was less in the SCLE group when compared with the LD group: 10% versus 36%.

CONCLUSIONS

We believe the SCLE technique is a reasonable treatment choice for femoral intramedullary nailing as it facilitates obtaining orthogonal views of the femur while possibly shortening surgery and fluoroscopy times.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Predicting proximal femur rotation by morphological analyses using translucent 3-dimensional computed tomography

BACKGROUND

Predicting rotation of proximal femur in femur fracture surgeries is important to prevent malrotation.

OBJECTIVE

We aimed to prevent malrotation by developing a simple guideline that enables the prediction of proximal femur rotation using translucent 3-dimensional computed tomography (3D CT).

DESIGN

Retrospective.

SETTING

One tertiary general hospital in the Republic of Korea.

PATIENTS

Thirty-six subjects who underwent CT angiographies for vascular evaluation.

INTERVENTION

Translucent 3D CT images were created from the CT data.

MAIN OUTCOME MEASURE

Morphologic ratios of the great trochanter (GT) and lesser trochanter (LT) with the hip center as a basic point were measured at neutral position and at 5°, 10°, 15°, 20°, 25°, and 30° of internal rotation (IR) and external rotation (ER). The rotation angles at which the GT ratio becomes 0.5 and 0.33 and the rotation angles at which the LT ratio becomes 0.0 and 1.0 were determined to serve as guide angles.

RESULTS

Both the proportion of GT and LT compared with proximal femur with hip center as a reference (GT and LT ratio) gradually increased in the shift from IR to ER. At a neutral position, the GT and LT ratios were approximately 0.4 and 0.5, respectively. At 10°-15° of ER, the approximate GT and LT ratios were 0.5 and 1.0, respectively. At 30° of ER, the GT ratio exceeded 0.6, and the LT ratio exceeded 1.0. Between 10° and 15° of IR, the GT ratio decreased to approximately 0.33 and the LT ratio decreased to 0.0, which indicated that the LT was invisible.

CONCLUSIONS

We suggested practical values which might be useful as a reference in the operating room practically and hope that our findings would be helpful to prevent malrotation while performing proximal femur or femur shaft surgeries.

A preliminary clinical evaluation of the "greater trochanter-head contact point" method for the intraoperative torsional control of femoral fractures

PURPOSE

In a previous study, our group introduced a simple non-invasive method for the intraoperative control of femoral torsion during closed nailing of femoral fractures using the shape of the greater trochanter and its relation to the femoral head. The aim of this study was to verify the results of our cadaveric study and transfer them into a clinical setup. We answered the questions: How much time is needed to perform the greater trochanter-head contact point method (GT-HCP)? How long is the radiation time?

METHODS

We examined 15 patients with femoral shaft fractures, to evaluate the GT-HCP method in a clinical setup. Using a standard fluoroscopic image intensifier (Ziehm, Erlangen, Germany), the greater trochanter-head contact angle was measured for both sides. All patients received a postoperative computer tomography (CT) to check the rotational malalignment. The mean of the CT results was then compared to the measurements of the GT-HCP method. The examiners performing the CT measurements were not aware of the GT-HCP results and vice versa.

RESULTS

No statistical significance could be detected between the CT and the GT-HCP method (p = 0.853). Eleven patients had very good results (≤5°), three had good results (6-10°) and one had poor results (>10°). The mean difference between CT and GT-HCP method was 3.7 ± 3.3°, which is acceptable. The radiation dose needed for the method was not large (0.2 ± 0.1 min), and could be lowered with the gaining experience of the examiners. Similarly, the overall time needed (12.1 ± 4.9 min) for the GT-HCP method could be reduced with the experience of the team.

CONCLUSION

Our study showed that the GT-HCP method is a precise and not particularly time consuming method for controlling anteversion during closed femoral nailing. Further clinical trials including a larger number of patients are required to establish this method in clinical practice.

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.

Accuracy of measurement of femoral anteversion in femoral shaft fractures using a computer imaging software: a cadaveric study

INTRODUCTION

Rotational malalignment after intramedullary nailing of femoral fractures remains an unresolved problem. Various techniques have been described to address this problem, with limited success. In this cadaveric study, we describe the determination of the femoral anteversion (FAV) angle utilizing a new imaging software program which allows us to generate and manipulate reformatted virtual images from standard DICOM (Digital Imaging and Communications in Medicine) images.

MATERIALS AND METHODS

Eleven intact femoral specimens were scanned by CT before and after fracture induction in standardized fashion. The obtained DICOM image datasets were uploaded to the new software tool. From this, we obtained reformatted virtual fracture fragment images, which enabled us to reconstruct the femoral anatomy and determine FAV measurements. We then compared FAV measurements before and after fracture induction to determine if there were any statistically significant differences.

RESULTS

Fracture induction generated 5 AO type A and 6 AO type B fractures. In the specimens prior to fracture induction, we were able to determine the mean FAV to be 17.94° ± 4.48°. Additionally, analysis of the fractured femoral specimens revealed the new mean FAV to be 16.26° ± 4.83°. Statistical analysis of these two measurement groups did not demonstrate statistical significance. When a sub-analysis was performed of the FAV measurements between the two different AO fracture types, there also were no statistically significant differences.

DISCUSSION

Through new imaging software that allows us to reformat standard DICOM images and generate virtual fracture fragments, we were able to determine the appropriate FAV. We feel that this technique can potentially be integrated into the imaging algorithm for femoral shaft fractures in the future, and can potentially optimize clinical outcomes by allowing the orthopaedic surgeon to determine precisely the appropriate native FAV.

Comparison of two techniques in achieving planned correction angles in femoral subtrochanteric derotation osteotomy

Increased femoral anteversion in cerebral palsy alters biomechanics of gait. Femoral subtrochanteric derotational osteotomies are increasingly performed to improve gait in cerebral palsy. The amount of angular correction can be determined and planned preoperatively but, accuracy in achieving planned angular correction has not been tested experimentally before. The aim of this study was to evaluate the accuracy of the two techniques in achieving planned angular correction. Sixteen dry femora were used in this study. Specimens in both groups were derotated to achieve a desired amount of correction with two different techniques, consecutively. In technique one, the cross section of the femur was assumed to be circular and the desired amount of angular correction was calculated and expressed in terms of surface distance by a geometric formula (surface distance=2×π×radius of femur). In both groups, derotations were made based on this surface distance calculation. Consecutively the same specimens were derotated by pins and guide technique. Femoral anteversion of specimens were measured before and after derotation by computerized tomography. There was a statistically significant differance in planned and achieved correction angles (P=0.038) in both subgroups derotated by the surface distance technique. When the two techniques were compared, there was significant difference (P=0.050) between high magnitude correction subgroups (subgroups 2 vs. 4). In conclusion, the results of this study highlighted the difficulty in achieving accurate derotation angles. Derotations based on guide-pins technique yielded more accurate results than derotations based on surface distance technique. In addition, surface diameter technique was not suitable when higher degrees of derotations are needed. In achieving a planned derotation angle two techniques are described for accuracy. Both the techniques have potential pitfalls resulting in malrotations. Surgeons must be aware of these obstacles and try to avoid them.

Reliability of the assessment of lower limb torsion using computed tomography: analysis of five different techniques

OBJECTIVE

Various methods have been described to define the femoral neck and distal tibial axes based on a single CT image. The most popular are the Hernandez and Weiner methods for defining the femoral neck axis and the Jend, Ulm, and bimalleolar methods for defining the distal tibial axis. The purpose of this study was to calculate the intra- and interobserver reliability of the above methods and to determine intermethod differences.

METHODS

Three physicians separately measured the rotational profile of 44 patients using CT examinations on two different occasions. The average age of patients was 36.3 ± 14.4 years, and there were 25 male and 19 female patients. After completing the first two sessions of measurements, one observer chose certain cuts at the levels of the femoral neck, femoral condylar area, tibial plateau, and distal tibia. The three physicians then repeated all measurements using these CT cuts.

RESULTS

The greatest interclass correlation coefficients were achieved with the Hernandez (0.99 intra- and 0.93 interobserver correlations) and bimalleolar methods (0.99 intra- and 0.92 interobserver correlations) for measuring the femoral neck and distal tibia axes, respectively. A statistically significant decrease in the interobserver median absolute differences could be achieved through the use of predefined CT scans only for measurements of the femoral condylar axis and the distal tibial axis using the Ulm method. The bimalleolar axis method underestimated the tibial torsion angle by an average of 4.8° and 13° compared to the Ulm and Jend techniques, respectively.

CONCLUSIONS

The methods with the greatest inter- and intraobserver reliabilities were the Hernandez and bimalleolar methods for measuring femoral anteversion and tibial torsion, respectively. The high intermethod differences make it difficult to compare measurements made with different methods.

Factors influencing neck anteversion during femoral nailing: a retrospective analysis of 220 torsion-difference CTs

BACKGROUND

Rotational malalignment is a well-known complication following intramedullary nailing of femoral shaft fractures. The hypothesis of this study is that various modifiable factors, such as position on the surgical table or nailing technique, influence the incidence of torsional abnormalities.

METHODS

For this retrospective study, we analysed the data of 220 consecutive patients with femoral shaft fractures and postoperative torsion-difference computed tomographies (CTs), performed from 2001 to 2009 in our institution. Mean age of the patients was 33±15 years. Average delay to surgery was 8±11 days. The average postoperative neck anteversion difference between both sides was 11±8°. A p value <0.05 was considered to be statistically significant.

RESULTS

The average postoperative neck anteversion difference between both sides was not significantly affected from the position of the patient on the surgical table (supine or lateral, p=0.698), the delay till surgery (p=0.989), the nailing technique (antegrade or retrograde, p=0.793; reamed or unreamed, p=0.930), the type of the implant (p=0.885) and the experience of the surgeon (p=0.055). Furthermore, the learning curve regarding this complication was long and not predictable.

CONCLUSIONS

We could not identify any risk factors that are associated with an increased incidence of torsional deformities, and thus our hypothesis could not be confirmed. The inability to identify such risk factors renders the prevention of this complication particularly problematic. The invention of new techniques for better intra-operative control of the torsion is probably the only solution to further reduce the incidence of postoperative malrotational deformities.

Pitfalls in the application of distal femur plates for fractures

Despite design features intended to aid the surgeon in restoring proper alignment, malunion and implant-related problems are relatively common after a distal femur fracture treated with plate fixation. This article presents case examples of these problems followed by a discussion of the relevant distal femoral anatomy, design features of modern locked distal femur plating systems, and technical points necessary to avoid malunion and implant-related problems when using these devices.

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.

The greater trochanter-head contact method: a cadaveric study with a new technique for the intraoperative control of rotation of femoral fractures

OBJECTIVE

To describe a new method for femoral rotational alignment during intramedullary nail insertion using the profile of the greater trochanter and its relation to the femoral head.

METHODS

Radiologically, the line that represents the posterior border of the greater trochanter comes in contact with the femoral head contour during external rotation. The degree of rotation to achieve this contact was measured on both lower extremities of 15 whole fresh-frozen cadavers and seven dried human femora using a standard image intensifier. Computed tomography was used in the dried femora to assess the femoral anteversion angle, the length of the femoral neck, and the neck-shaft angle.

RESULTS

The side difference of the greater trochanter-head contact angle was 6° or less in 14 of 15 whole fresh-frozen cadavers. Regarding the dried human femora, this angle had a strong positive correlation with femoral neck anteversion angle (r = 0.9), whereas no statistically significant correlation could be detected with the neck length or the neck-shaft angle.

CONCLUSION

Our described method is simple to execute because it depends on a definite point of measurement. Furthermore, an angle is recorded for each extremity, which enables us to estimate the amount of the rotational difference. This method does not depend on special views, especially at the hip, but only a direct anteroposterior view with gradual internal rotation of the image intensifier.

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.

Long-term functional implications of the iatrogenic rotational malalignment of healed diaphyseal femur fractures following intramedullary nailing

BACKGROUND

The long-term functional implications for patients with iatrogenic femoral malrotation following femoral intramedullary nail fixation remain unclear. This study examined the extent and direction of rotational alignment of the femur treated with intramedullary nail fixation and its long-term functional effects on patients' standing, walking, and subjective outcome.

METHODS

Rotational alignment was measured using a CT-based protocol. Foot alignment while standing or walking was determined bilaterally using a pressure mat. Subjective functional outcome was assessed using a questionnaire.

FINDINGS

Sixteen patients (5F, 11 M; age: mean 44.3 years, range 24-75 years) with a healed femur fracture were included. Femur alignment demonstrated internal rotation in five patients (mean 6°; range 2-13°), and external rotation in 11 (mean 18°; range 3-32°). Static foot rotation demonstrated neutral rotation in two patients, internal rotation in four (mean 13°; range 5-22°), and external rotation in 10 (mean 15°; range 5-24°). Dynamic foot rotation demonstrated neutral rotation in two patients, internal rotation in two (mean 11°; range 4-26°), and external rotation in 12 (mean 11°; range 3-22°). There was a trend for increasing dynamic malrotation with femoral rotation (r(2)=0.27; p=0.055). In half the patients, dynamic foot rotation correlated with the extent of femoral malrotation. There was no association (p=0.6) between overall patient satisfaction (10 fully satisfied; 5 partially satisfied; and 1 dissatisfied) and foot alignment.

INTERPRETATION

Patients can compensate for even significant femoral malrotation and tolerate it well. External femoral malrotation appears to be better compensated/tolerated than internal malrotation.

Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures

OBJECTIVE

To determine the incidence of rotational malalignment in distal femoral and proximal tibial fractures using computed tomography (CT) scanograms following indirect reduction and internal fixation with the minimally invasive percutaneous osteosynthesis (MIPO) technique.

DESIGN

Prospective Cohort.

SETTING

Level I Trauma Centre.

PATIENTS/PARTICIPANTS

A total of 27 consecutive subjects, and 14 proximal tibia and distal femur fractures.

INTERVENTION

All patients underwent indirect reduction and internal fixation with a MIPO plating system. A CT scanogram to measure rotational malalignment between the injured and non-injured extremity was then undertaken.

MAIN OUTCOME MEASURE(S)

Femoral anteversion angles and tibial rotation angles between the injured and non-injured extremities were compared. Malrotation was defined as a side-to-side difference of >108.

RESULTS

A total of 14 postoperative tibias and 13 femurs underwent CT scanograms. Three females and 11 males with an average age of 38.1 years sustained proximal tibia fractures and six females and seven males with an average age of 55.8 years sustained distal femur fractures. The difference between tibial rotation in the injured and the non-injured limbs ranged from 2.7 to 40.08 with a mean difference of 16.28(p = 0.656, paired T-test). Fifty percent of the tibias fixed with MIPO plates were malrotated >108 from the uninjured limbs. The difference between femoral anteversion in the injured and non-injured limbs ranged from 2.0 to 31.38 with a mean difference of 11.58 (p = 0.005, paired T-test). A total of 38.5% of the distal femurs fixed with MIPO plates were malrotated >108 from the uninjured limb.

CONCLUSIONS

Following fixation of distal femoral and proximal tibial fractures, the incidence of malrotation was 38.5% and 50%, respectively. The difference of the mean measures was significant for femoral malrotation; however, statistical significance could not be demonstrated for tibial malrotation.The incidence of malrotation following MIPO plating in this study is much higher than that quoted in previous studies.

Femoral malrotation following intramedullary nail fixation

Intramedullary nailing of femoral shaft fracture can result in inadvertent malalignment. Malrotation is the most common cause of deformity, but it is underrecognized, in part because of the difficulty in accurately assessing rotation as well as the variation that exists in normal anatomy. The consequences of femoral malrotation are not completely understood. However, initial biomechanical studies suggest that it causes a substantial change in load bearing in the affected extremity. Clinical examination, fluoroscopy, and ultrasonography are useful in measuring femoral rotational alignment intraoperatively and postoperatively. CT is useful in the identification of the degree of malrotation and in surgical planning.

CT evaluation of torsional malalignment after intertrochanteric fracture fixation

INTRODUCTION

Trochanteric fractures are commonly stabilized either by intramedullary nailing or plate and screw fixation after reduction on the orthopaedic surgical table under radiological guidance.

HYPOTHESIS

Closed trochanteric fracture anatomic reduction is difficult in the transversal plane.

OBJECTIVES

The objective of this prospective study was to assess the rotational malalignment induced after reduction and osteosynthesis of trochanteric fractures.

PATIENTS AND METHODS

Prospective study including 40 patients (mean age, 78 years; range, 51-90 years) operated for a trochanteric fracture between January 2007 and September 2008. Fourteen fractures were treated using DHS™ (Synthes™) plate and screw fixation and 26 with intramedullary nailing (trochanteric nail™, Stryker™). All these patients underwent postoperative CT of the pelvis during their hospitalization with measurement of anteversion of the operated and healthy femoral necks at the posterior condyles. The evaluation criterion was whether or not there was malalignment greater than 15° on the operated side compared to the healthy side.

RESULTS

The mean anteversion was 14.2° for the healthy side and 23° for the operated side. The mean rotational malalignment was 15.3°. Forty percent of the rotational malalignments were greater than 15°, with a majority of cases showing excess internal rotation (35%) of the distal fragment.

CONCLUSION AND DISCUSSION

The rate of internal rotational malalignment of the distal fragment greater than 15° was high (40% of this series). This should encourage surgeons to reduce the excess internal rotation that tends to be attributed to the distal fragment during preoperative reduction of these fractures.

LEVEL OF EVIDENCE

Level III. Prospective diagnostic study with no control group.

Correction of malalignment in proximal femoral nailing--Reduction technique of displaced proximal fragment

INTRODUCTION

External rotation, abduction, and flexion of the proximal fragment in proximal femoral fracture are one of the main obstacles in nailing. We introduced simple surgical technique using a long hemostatic forceps to achieve fracture reduction and to facilitate preparation of the nail entry site.

METHOD

Using this reduction method, 16 patients with displaced subtrochanteric or proximal femoral shaft fracture were treated through cephalomedullary or femoral nailing between January 2005 and May 2007.

RESULTS

The difference of the neck-shaft angle in the AP view compared to the normal side was 2.2 degrees (range, 0-5 degrees). Anterior angulation in the lateral view was 1.6 degrees (range, 0-15 degrees). One case of malunion was caused by too anterior nail insertion in the lateral view. Bone union was achieved in all cases with an average consolidation time of 5.1 months (range, 3-9 months).

CONCLUSION

A simple reduction technique using readily available instruments in the operating room (hemostatic forceps) is quite useful in reducing proximal femoral fragments in cephalomedullary or femoral nailing.

The cortical step sign as a tool for assessing and correcting rotational deformity in femoral shaft fractures

OBJECTIVES

Rotational malalignment during femoral nailing is common. The difference in cortical width of the proximal and distal fracture fragments, the cortical step sign, is a commonly used yet poorly studied method of evaluating rotational alignment. This study aims to critically analyze the cortical step sign in cadaveric specimens using radiographic and direct measurements.

METHODS

One-centimeter segments from 20 cadaveric femora were harvested from the proximal, middle, and distal diaphyses. The medial and lateral cortical widths were measured in neutral and at 10 degrees , 20 degrees , and 30 degrees of internal rotation and external rotation directly from the gross specimens and indirectly using radiographs and cross-sectional imaging.

RESULTS

Anatomic, radiographic, and cross-sectional imaging measurements all demonstrated that cortical width changes with femoral rotation. Rotation (both internal rotation and external rotation) of the proximal and middle segments led to a decrease in medial cortical width and lateral cortical width in 70% to 100% of samples (up to 2.2 mm, or 20% of cortical width) indicating that the cortices are thickest directly medially and laterally in neutral rotation. In the distal femur, however, internal rotation and external rotation led to an increase in medial cortical width and lateral cortical width in 80% to 95% of cases (up to 1.75 mm), except in the case of the medial cortical width in internal rotation, which decreased in 80% of the specimens (up to 1.3 mm).

CONCLUSIONS

The cortical step sign, or incongruity of cortical widths on either side of a femur fracture, is indicative of rotational malreduction. Whether such malreduction is the result of internal rotation or external rotation, however, cannot be easily determined from this radiographic sign.

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.

Intramedullary nailing of femoral shaft fractures: current concepts

Intramedullary nailing is the preferred method for treating fractures of the femoral shaft. The piriformis fossa and greater trochanter are viable starting points for antegrade nailing. Alternatively, retrograde nailing may be performed. Each option has relative advantages, disadvantages, and indications. Patient positioning can affect the relative ease of intramedullary nailing and the incidence of malalignment. The timing of femoral intramedullary nailing as well as the use of reaming must be tailored to each patient to avoid systemic complications. Associated comorbidities, the body habitus, and associated injuries should be considered when determining the starting point, optimal patient positioning for nailing, whether to use reduction aids as well as which to use, and any modifications of standard technique. Intramedullary nailing of diaphyseal femur fractures provides a stable fixation construct that can be applied using indirect reduction techniques. This method yields high union rates and low complication rates when vigilance is maintained during preoperative planning, the surgical procedure, and the postoperative period.

Femoral fracture malrotation caused by freehand versus navigated distal interlocking

OBJECTIVES

Rotational deformity following intramedullary nailing of femoral shaft fractures is a clinically significant and underdiagnosed problem. Intraoperative determination of rotation is difficult and may be caused by several factors. The insertion of interlocking screws at a slightly oblique angle may cause a substantial degree of rotational deformity, and this factor has not been evaluated as a cause of malrotation.

METHODS

In eight paired cadaveric femurs, a midshaft transverse fracture was created and an antegrade nail was placed. The specimens were placed in a custom jig which allowed free rotation of the distal segment. Distal interlocking was performed using either a freehand technique or with navigation, and femoral anteversion was measured before and after interlocking to determine the change caused by the interlocking screw.

RESULTS

Freehand placement led to rotational shift up to 7 degrees (mean, 5.8 degrees ; range, 4-7 degrees ), and navigated insertion led to a change of 2.0 degrees (range, 1-3 degrees ; p<0.05). In addition, drill-nail contact and a visible shift of the fracture site occurred in all freehand trials, whereas in the navigation group, contact occurred in only one trial without fracture movement.

CONCLUSIONS

Freehand distal interlocking may be a substantial cause of rotational deformity, and the assistance of computer navigation systems may improve this malrotation.

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.

Computer navigation allows for accurate reduction of femoral fractures

Femoral nailing for reduction and stabilization of femoral fractures is a common orthopaedic procedure. However, angular and rotational malalignment is not an infrequent result, and extensive use of fluoroscopy is commonly involved. We tested the accuracy of a computerized navigation system to enhance multiplanar fracture reduction and to decrease the requirement for fluoroscopy. We used a cadaveric femur fixed in a simulator and optically tracked. After obtaining five fluoroscopic images for each reduction attempt, accuracy measurements were taken. We first measured alignment of the intact bone using the navigation system, followed by open and blind reduction of simple and segmental fractures. For the blind, closed reduction trials, the accuracy of restoration of femoral length was 1.2 +/- 0.4 mm (mean +/- standard deviation) for a simple fracture and 1.9 +/- 1.8 mm for a segmental fracture. Rotational accuracy was 1.7 degrees +/- 1.9 degrees and 2.5 degrees +/- 1.8 degrees, respectively. Open reduction using this model yielded no difference between the reduced fracture and the intact bone in coronal and rotational alignment. Computerized navigation has the potential for increasing precision in fracture reduction while minimizing fluoroscopic requirements.

Intraoperative cone-beam CT for correction of periaxial malrotation of the femoral shaft: a surface-matching approach

Limb length, alignment and rotation can be difficult to determine in femoral shaft fractures. Shaft axis rotation is particularly difficult to assess intraoperatively. Femoral malpositioning can cause deformity, pain and secondary degenerative joint damage. The aim of this study is to develop an intraoperative method based on cone-beam computed tomography (CBCT) to guide alignment of femoral shaft fractures. We hypothesize that bone surface matching can predict malrotation even with severe comminution. A cadaveric femur was imaged at 16 femoral periaxial malrotations (-51.2 degrees to 60.1 degrees). The images were processed resulting in an unwrapped bone surface plot consisting of a pattern of ridges and valleys. Fracture gaps were simulated by removing midline CT slices. The gaps were reconstituted by extrapolating the existing proximal and distal fragments to the midline of the fracture. The two bone surfaces were then shifted to align bony features. Periaxial malrotation was accurately assessed using surface matching (r2 = 0.99, slope 1.0). The largest mean error was 2.20 degrees and the average difference between repeated measurements was 0.49 degrees. CBCT can provide intraoperative high-resolution images with a large field of view. This quality of imaging enables surface matching algorithms to be utilized even with large areas of comminution.

Detection of fibular torsional deformities after surgery for ankle fractures with a novel CT method

BACKGROUND

Substantial fibular torsional deformities were detected after surgery for ankle fractures combined with a lesion of the syndesmotic complex using a novel CT analyzing method.

METHODS

In a prospective study, 61 patients with ankle fracture dislocations were treated with trans-syndesmotic screw fixation of the distal tibiofibular joint. Postoperative axial CT scans of both lower legs under standardized leg positioning conditions were made and analyzed with three different methods. Method 1 (M1) used proximal and distal CT planes of the lower leg for detection of the fibular torsional angle, method 2 (M2) considered only the angle at the distal tibiofibular joint, and method 3 (M3) measured the angles between the fibular and tibial tangents at the distal tibiofibular joint. Twenty patients with fibular torsional asymmetries of more than 10 degrees were evaluated clinically 6 to 34 months postoperatively with the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score.

RESULTS

Thirty-five of the 61 patients had torsional side-to-side differences of more than 10 degrees. M1 and M2 showed statistically significant differences compared to M3 (p = 0.001). Validity was controlled by interobserver data, variation coefficients were low for M1 and M2. Clinically, six of 20 patients with torsional differences of more than 10 degrees had excellent results, while seven had good results and seven had moderately functional results. Six of the seven with moderate results had fibular torsional differences of more than 15 degrees, two of the seven patients with good outcomes. Torsional results of M1 and M2 correlated with the AOFAS score (r = -0.506).

CONCLUSIONS

Of the 61 ankle fractures with ruptures of the syndesmotic complex, 25% showed torsional side-to-side differences of more than 10 degrees on proximal and distal CT planes. This CT technique correlated with the AOFAS score and could help determine when early operative revision is indicated.

Derotation of post-traumatic femoral deformities by closed intramedullary sawing

Different techniques and devices have been used for correction osteotomies of bones in patients with malalignments. The most frequently used technique for rotational deformities of the femur and tibia is open osteotomy with an oscillating saw and pre-drilled holes with all well-known drawbacks of open surgery. An intramedullary device with an adapted minimal-invasive surgical technique allows intramedullary osteotomy of the bone preserving the surrounding soft tissue. We performed femoral osteotomies with an intramedullary saw followed by static interlocking nailing in 14 patients with post-traumatic rotational deformity in the femur. Twelve patients had an external rotational deformity of the femur ranging between 26 and 63 degrees , one had an additional leg-shortening of about 4 cm. Two patients had internal rotational deformities. In two patients with delayed fracture healing union was achieved within one year without secondary surgery. Post-operative clinical assessment and CT-scans revealed good derotation results with deformities of less than 4 degrees in all cases. No device-related complications were observed. Therefore, we conclude that "closed" osteotomy with an intramedullary saw is a minimal-invasive, safe and reliable option for derotation procedures in the femur.

Avoiding rotational malalignment after fractures of the femur by using the profile of the lesser trochanter: an in vitro study

INTRODUCTION

Intramedullary (IM) nailing has become the preferred method of treatment for femoral shaft fractures in adults. Rotational malalignment is an important complication, established during operation. The incidence of rotational malalignment (> or = 15 degrees) has been reported to be between 20% and 30%. It might be avoided intra-operatively by using quantitative imaging techniques, with the profile of the contralateral lesser trochanter serving as a reference.

MATERIALS AND METHODS

With the help of a C-arm image intensifier, five surgeons tried to determine the neutral state of ten prepared cadaver femora. They could only look at the C-arm screen and were blinded to the actual femur. Per observer three measurements were done per femur. The first measurement (method I) was done without a reference, while the second (method II) used a reference image of the femur in a neutral state. The third method (method III) added a lesser trochanter quantifying computer program. After positioning of the femur, the difference in rotational state compared with the neutral state was measured with an inclinometer.

RESULTS

Without reference, malrotations up to 27 degrees were found. Methods II and III proved to be significantly better (p < 0.0001). These two methods showed malrotation of 2.2 degrees (+/-1.5 degrees) and 2.3 degrees (+/-1.7 degrees), respectively. External or internal malrotation occurred with all three methods equally frequently. No difference was found between observers.

CONCLUSIONS

Using the contralateral lesser trochanter as a reference is an accurate method to minimize malrotation of a femur. Quantifying the profile of the lesser trochanter with computer assistance did not improve these results. Clinical results in the future still have to support these in vitro findings.

Compensation for rotational malalignment after intramedullary nailing for femoral shaft fractures. An analysis by plantar pressure measurements during gait

INTRODUCTION

Even though rotational malalignment due to a femoral shaft fracture leads to clinical complaints, a large number of patients may have none of significance. The ability to compensate may play a role. The purpose of this study is to give insight into aspects of compensatory gait of patients with a femoral malrotation and the relation with clinical complaints.

METHODS

In a cross-sectional laboratory setting, foot-progression angles (FPA) during gait were measured using a foot scan device. Results were related to CT determined femoral torsion and clinical complaints.

RESULTS

Patients with external (EMR) or internal malrotation (IMR) showed differences in foot-progression angles (DeltaFPA) in the same direction of their malrotation. Compared to IMR patients, EMR patients appeared to compensate less for their malrotation. No statistically significant differences were detected between these groups for absolute and relative compensation. EMR patients scored worse at the Oxford 12-item and WOMAC score and experienced more problems executing demanding activities than do patients without malrotation. Correlations were found between Oxford 12-item and WOMAC score and relative compensation.

CONCLUSIONS

Femoral torsion and the FPA are strongly related. All patients compensate towards normal values of FPA at their fractured side. Patients who are less able to compensate have more physical complaints. EMR patients tend to have more complaints and difficulty compensating.