Optimal entry point for retrograde femoral nailing

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Optimal entry point for antegrade and retrograde femoral intramedullary nails

Surgical management of femoral shaft fractures with intramedullary nails has become the standard of care, with multiple options for entry point described, including piriformis entry, trochanter entry and retrograde femoral nails. Our present review describes the surgical anatomy of the proximal and distal femur and its relation to different entry points for intramedullary femoral nails. In addition, we reviewed relative indications for each technique, difficulties associated and possible complications.

Imaging Evaluation of Insertion Point Accuracy in Retrograde Intramedullary Femoral Nailing

Objective

When compared with visual retrograde intramedullary nail placement in the femur, fluoroscopic retrograde intramedullary nail placement in the femur improved the accuracy of insertion.

Methods

Ninety-six patients treated with retrograde intramedullary nailing of the femur for femoral fracture were included in this retrospective case-control study, including 48 patients treated with nailing under direct vision and 48 patients treated with nailing under fluoroscopy. Influencing factors potentially associated with the deviation of the needle insertion point on the coronal and sagittal planes (including the needle insertion method, use of limited open reduction, side, intramedullary nail diameter, mechanism of injury, and fracture classification) were analyzed univariately; then, the variables with a p value < 0.20 on univariate analysis were included in the linear regression equation to assess the independent factors associated with needle insertion point deviation.

Results

On the coronal plane, the insertion point deviation in the visual nail placement group (1.11 ± 4.08 mm) was not significantly different (p = 0.13) from that in the fluoroscopic nail placement group (−0.44 ± 3.48 mm); on the sagittal plane, the insertion point deviation in the visual nail placement group (4.91 ± 4.67 mm) was significantly greater than that in the fluoroscopic nail placement group (2.08 ± 2.97 mm) (p < 0.01). Visual nail placement was a risk factor for insertion point deviation on the sagittal plane compared with fluoroscopic nail placement (β = −0.84, p < 0.01).

Conclusion

Compared with visual nail placement, fluoroscopic nail placement improves the accuracy of insertion on the sagittal plane, with no difference between the two methods on the coronal plane. These findings indicate that surgeons should exercise more caution when placing nails under direct vision.

Femoral Shaft Fracture in Post-polio Syndrome Patients: Case Series from a Level-I Trauma Center and Review of Literature

BACKGROUND

Femoral shaft fracture in patients of post-polio syndrome (PPS) represents an uncommon yet complex injury pattern. Poorly developed soft-tissue envelope, decreased muscle bulk, reduced vascularity, regional osteopenia, joint contractures, and altered bony anatomy impose significant surgical challenges. Thorough pre-operative planning is imperative as each case requires individualized approach and method of fixation. The aim of the study was to analyze the clinical outcomes in such patients following fracture fixation and to assess the surgical challenges encountered and provide solutions.

MATERIALS AND METHODS

A retrospective case series of 33 patients with femoral shaft fracture in PPS limbs was undertaken. Mode of injury, method of fixation, surgical time, intra-operative blood loss, union time, and complications were recorded.

RESULTS

Low-energy fall was the most common mechanism of injury (73%). Thirty-three patients underwent fixation with intramedullary nailing being the most common mode (79%). Femoral canal diameter, femoral bow, fracture location and morphology and clinical deformities of the patients are key governing factors that determine the choice of implant. Locking plates, pre-contoured anatomical plates, and titanium elastic nailing system offer an alternative in patients unsuitable for nailing. With no difference between various implants, average time for bone healing was 13.8 ± 4.4 weeks. All patients resumed full weight-bearing mobilization and returned to pre-injury activity status at the end of 6 months post-surgery.

CONCLUSION

With detailed pre-operative work-up, contemplating intra-operative difficulties, individualized surgical plan, careful handling of soft tissues, and availability of back-up implants, good clinical outcomes can be achieved in femur fractures in PPS patients.

Evaluation of anatomical axis-joint center distance and anatomical axis-joint center ratio in distal femur and proximal tibia in coronal plane of Indian population

BACKGROUND

Radiographic evaluation of the anatomical geometry of the bone is important for executing reconstructive surgeries like deformity correction, limb lengthening and joint replacements. Various studies have been done in the past to define the anatomic placement of implant inside the bone. The aim of this study is to evaluate the distance between the anatomical axis and joint center of the distal femur (aJCD-f) and proximal tibia (aJCD-t) along with the ratio of anatomical axis-joint center distance of distal femur (aJCR-f) and proximal tibia (aJCR-t) of the skeletally mature individual of Indian population along with its application in day to day practice.

METHODS

Data is procured from the standard radiographs of the knee on large films. The anatomical axis is drawn on both sides of tibia and femur in a standard fashion. These lines intersect the horizontal drawn line at the intercondylar notch of femur and joint orientation line of the tibia. The aJCD-f, aJCD-t, aJCR-f, aJCR-t are then measured. Also the center of the inter-spinous distance of the tibia is measured from the anatomical axis (aSCD-t).

RESULTS

A total of 182 x-rays of skeletally mature individual were included with mean age of 46.35 ± 13.93 years. Of them 81 were males and 101 were females. There were 89 x-ray of left side and 93 x-ray of right side. The mean width of the femur at the intercondylar notch is found to be 76.78 mm (±7.40). The mean aJCD-f is found to be 3.87 mm (±2.44), aJCR-f to be 0.50 (±0.06). The mean width of the tibia is found to be 76.80 mm (±6.48). The aJCD-t is found to be 2.20 mm (±1.41), aJCR-t to be 0.50 (±0.03). The aSCD-t at the level of tibial spine is found to be -0.23 mm (±2.84). There was significant difference in the width of the femoral condyle of males 82.13 mm (±0.65) and females 72.48 mm (±0.55). Males showed mean aJCD-f of 3.59 mm (±2.42) and females showed 4.10 mm (±2.46). The aJCR-f is found to be significantly different between males 0.49 (±0.05) and females 0.51 (±0.07). There is significant difference between the width of the proximal tibia between males 80.83 mm (±0.68) and females 73.56 mm (±0.46). The aJCD-t of males and females is found to be 2.28 mm (±1.25) and 2.16 mm (±1.54) respectively. The aJCR-t is found to be significantly different between males 0.49 (±0.03) and females 0.50 (±0.04). While the mean distance of the anatomical axis from the lateral tibial spine is 0.23 mm lateral to the center of the inter-spinous distance and is found to be same in both males and females -0.23 mm (±2.84).

CONCLUSION

The coronal plane parameter like aJCD, aJCR of femur and tibia and aSCD-t of tibia can be a useful parameter to calculate in the 'real world' settings for reconstructive surgeries like deformity correction, nailing through the knee for femur and tibia as well as replacement surgeries around knee.

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Impacted Steel Sleeves for a minimally invasive approach in intramedullary nailing

A custom-made instrument set of Steel Sleeves was developed to assist the insertion of reamers and intramedullary devices for fixation of long bone fractures or lengthening procedures with intramedullary nails. By use of the Steel Sleeves, migration of the entry point is prevented and protection of the bone and soft tissue at the entry point is guaranteed. In addition, the principle of a closed working channel for trans-articular approaches can be provided. In this article, a description of properties and clinical application of custom-made steel sleeve instrument set is provided.

Accidental external rotation of distal interlock jig in retrograde femoral nailing can lead to more prominent screws

OBJECTIVE

Symptomatic distal interlocking screws in retrograde femoral nailing are common due the difficulties of imaging the trapezoidal femur. Screws appearing to have appropriate length on imaging may possibly be prominent, creating symptoms. Screw trajectory may influence the degree of this radiographic error. We hypothesize that external rotation of screw trajectory will increase measurement error of screw length.

DESIGN

Retrospective.

SETTING

Urban Level I Tertiary Trauma Center.

PARTICIPANTS

283 patients with Computer Tomography (CT) scans of the native knee were retrospectively identified. Simulation was done of the trajectory of an interlock at 20 mm and 40 mm proximal to the nail entry point, which represent common screw positions associated/not associated respectively, with removal. The distance between the radiographic medial cortex and the tip of the transverse screw was calculated (D). The angle (Ψ) between the transverse trajectory and a modified trajectory aimed at the most medial cortex to avoid radiographic measurement error was calculated. Geometric modeling was utilized to calculate the measurement error (D) in the event of accidental external rotation. The angle of the medial slope was also measured (Θ).

INTERVENTION

Review of CT imaging of normal distal femora.

MAIN OUTCOME MEASUREMENTS

CT measurements of distal femora.

RESULTS

The mean distance (D) at 20/40 mm was 4.21 [95%CI 4.02-4.402] and 2.03 mm [95%CI 1.78-2.83], respectively (p < 0.0001). The mean angle (Ψ) between the transverse and modified trajectory at 20/40 mm was 12° [95%CI 11.5-12.5] and 9.60° [95%CI 9-10.2], respectively (p < 0.0001). External rotation by a similar amount nearly triples the measured difference (D). The measured medial slope was significantly increased as screws were placed more proximal (Θ_{20 mm} 46.5 vs Θ_{40 mm}: 48.7 °, p < 0.00001).

CONCLUSION

The distance between the perceived medial cortex and the tip of the most transverse screw is 4.21 mm and could account for painfully prominent screws. In more proximal screws this distance is decreased. Internal rotation of the screw trajectory 12° can reduce this distance (D), which has implications in nail design. External rotation, amplifies this difference nearly three-fold. Surgeons should avoid external rotation of the aiming arm to prevent prominent screws.

Iatrogenic Trochlear Chondral Defects After Anterolateral Placement of Retrograde Femoral Nails

Femoral shaft fractures are common injuries with an incidence of 37.1 per 100,000 person-years in the United States. Retrograde femoral nailing is an increasingly used treatment strategy to manage these injuries, particularly in fractures below stemmed hip prostheses, in supracondylar or distal femur fractures, in fractures in pregnant or obese patients, and when concomitant ipsilateral acetabular/pelvic ring fractures are present. Retrograde fixation has been shown to be a viable option with union rates comparable to antegrade intramedullary nailing. Despite having excellent results in the treatment of femoral fractures, retrograde femoral nails have been associated with iatrogenic patellofemoral chondral damage that may occur because of malpositioning of the intramedullary nail at the entry point. The objective of this case report is to describe 2 patients who suffered iatrogenic trochlear chondral defects after retrograde femoral nailing and subsequently underwent osteoarticular allograft transplantation surgery.

Editorial Commentary: Retrograde Femoral Nail Malpositioning Can Destroy Knee Cartilage

Retrograde femoral nail malpositioning can obviously destroy knee trochlear cartilage. A solution is osteochondral allograft transplantation surgery. Although case reports are rarely published in Arthroscopy, we make an exception and publish a report of 2 cases of this complication (and how to treat it) because exposure of complications that have not been previously well-reported could allow future surgeons, and their patients, to solve-and, preferably, proactively avoid-similar problems.

Insertion-related pain with intramedullary nailing

The use of intramedullary nails for the treatment of long bone fractures has become increasingly frequent over the last decade with gradually expanding indications and technological advances. Improved biomechanics relative to plates and less direct fracture exposure are some of the potential benefits of intramedullary nails. However, persistent insertion-related pain is common and may limit satisfactory long term outcomes. The etiologies of this phenomenon remain unclear. Proposed theories for which there is a growing body of supporting evidence include hardware prominence, suboptimal nail entry points leading to soft tissue irritation and structural compromise, local heterotrophic ossification, implant instability with persistent fracture micromotion, and poorly defined insertional strain. Many factors that lead to insertion-related pain are iatrogenic, and careful attention to detail and refined surgical techniques will optimize outcomes.

Influence of Femoral Component Design on Retrograde Femoral Nail Starting Point

PURPOSE

Our experience with retrograde femoral nailing after periprosthetic distal femur fractures was that femoral components with deep trochlear grooves posteriorly displace the nail entry point resulting in recurvatum deformity. This study evaluated the influence of distal femoral prosthetic design on the starting point.

METHODS

One hundred lateral knee images were examined. The distal edge of Blumensaat's line was used to create a ratio of its location compared with the maximum anteroposterior condylar width called the starting point ratio (SPR). Femoral trials from 6 manufacturers were analyzed to determine the location of simulated nail position in the sagittal plane compared with the maximum anteroposterior prosthetic width. These measurements were used to create a ratio, the femoral component ratio (FCR). The FCR was compared with the SPR to determine if a femoral component would be at risk for retrograde nail starting point posterior to the Blumensaat's line.

RESULTS

The mean SPR was 0.392 ± 0.03, and the mean FCR was 0.416 ± 0.05, which was significantly greater (P = 0.003). The mean FCR was 0.444 ± 0.06 for the cruciate retaining (CR) trials and was 0.393 ± 0.04 for the posterior stabilized trials; this difference was significant (P < 0.001).

CONCLUSIONS

The FCR for the femoral trials studied was significantly greater than the SPR for native knees and was significantly greater for CR femoral components compared with posterior stabilized components. These findings demonstrate that many total knee prostheses, particularly CR designs, are at risk for a starting point posterior to Blumensaat's line.

[Nailing of metaphyseal fractures]

Nailing of metaphyseal fractures demands thorough preoperative planning. The trauma surgeon has to take the specific morphology of the fracture, the individual anatomy of the broken bone, and the design and characteristics of the selected implant into consideration. The fracture has to be precisely reduced and the reduction controlled during nail insertion. The reduction technique and reduction aids must be chosen preoperatively. The nail has to be introduced with care and brought to its correct and ideal position. Only after successful proximal and distal interlocking can the nail become the central weight bearing implant, which holds the fracture stable and reduced. In the following contribution, the specific problems of reduction and nail fixation of metaphyseal fractures of the proximal humerus, proximal and distal femur, and proximal and distal tibia together with the needed reduction and fixation aids are presented.

Blocking screws: an adjunct to retrograde nailing for distal femoral shaft fractures

PURPOSE. To review records of 11 patients who underwent retrograde nailing in conjunction with blocking screws to aid fracture reduction for distal femoral shaft fractures. METHODS. Records of 8 men and 3 women aged 27 to 60 (mean, 41) years who underwent retrograde nailing with the use of blocking screws for distal femoral shaft fractures were reviewed. Two of the fractures were open and graded as Gustilo-Anderson grade II. The mean surgical delay was 2 (range, 1-5) days. RESULTS. All fractures united after a mean of 14 (range, 11-16) weeks without malalignment. There was no screw breakage, screw bending, or wound infection. CONCLUSION. Blocking screws increase the stability of the construct and thereby minimise macro-motion at the fracture site.

Analysis of postoperative knee sepsis after retrograde nail insertion of open femoral shaft fractures

OBJECTIVES

Retrograde nailing of open femoral fractures has presumed increased risk of knee sepsis. Our hypothesis was that the incidence of secondary knee infection after retrograde nailing of open femoral fractures is low.

DESIGN

Retrospective, multicenter.

SETTING

Four Level I trauma centers.

PATIENTS AND METHODS

A retrospective review of prospective trauma registries and fracture databases identified all open femoral fractures treated with retrograde intramedullary nailing from January 1, 2003, through February 15, 2007. Patients with ballistic injuries and those with less than 1 month follow up were excluded. Ninety-three open femoral fractures were identified in 90 patients. We defined a septic knee as a knee with infection that required reoperation with arthrotomy or arthroscopy. Infections at an open fracture site were defined as those treated with local irrigation and débridement and intravenously and/or orally administered antibiotics.

INTERVENTION

Open femoral shaft fractures treated with a retrograde approach.

MAIN OUTCOME MEASUREMENTS

Occurrence of an ipsilateral postoperative septic knee.

RESULTS

One acute septic knee was identified (1.1%; 95% confidence interval, 0.0%-3.2%) noted at time of repeat irrigation and débridement of a massive degloving wound that left no skin coverage over the knee. We also observed one late knee sepsis 2.5 years after the index procedure occurring after quadricepsplasty. The nail had been removed 1.5 years before surgery, so we did not include that case in our knee sepsis rate. Two additional infections at the open wound site did not involve the knee.

CONCLUSIONS

Previous publications have argued that retrograde nailing of open femoral fractures provides a potential conduit for knee infection. Our data show that risk of a septic knee as a direct result of retrograde nailing of an open femoral fracture is relatively low (1.1%; 95% confidence interval, 0.0%-3.2%). To our knowledge, this is the first case series to document the relative safety associated with retrograde nailing of open femoral fractures.

Percutaneous/minimally invasive techniques in treatment of femoral shaft fractures with an intramedullary nail

Intramedullary nailing of the femur is often the treatment of choice in isolated fractures of the femoral shaft. Some surgeons are reticent to use intramedullary nailing for proximal and distal femoral fractures. However, indications for femoral nailing can be appropriately extended to highly comminuted fractures as well as distal and proximal fractures when the correct technique and reduction maneuvers are utilized. Implementation of these techniques will also respect the critical soft tissue envelope that is so important in fracture healing. Deforming forces of the muscles of the hip, knee and thigh are neutralized with reduction tools applied percutaneously, blocking screws and Schanz pins. Mastery of these techniques and appropriate reduction are incumbent on the orthopaedic surgeon treating femoral shaft fractures.

Case report: Patella baja after retrograde femoral nail insertion

Patella baja is a rare condition that can result from conditions involving trauma around the knee. Risk factors are believed to include scar tissue formation in the retropatellar fat pad, extensor mechanism dysfunction, and immobilization in extension. Early recognition and aggressive treatment are critical components in minimizing long-term disability. We present a case report of a woman with a fracture of the femoral diaphysis who underwent retrograde placement of an intramedullary nail. Subsequent followup revealed development of patella baja with resultant disability. The diagnosis was made late and the treatment was ineffective. Although patella baja has been reported in trauma around the knee, causative factors include retrograde femoral nailing. We believe early recognition and institution of treatment are important.

ENTRY POINT FOR THE ANTEGRADE FEMORAL INTRAMEDULLARY NAIL: A CADAVER STUDY

Objective: To analyze the natural exit of the wire guides in major trochanter through retrograde femoral approach, in cadaver specimens. Material and Method: 100 femurs had been perforated between the femoral condyles, at 1.2 cm of the intercondylar region. A 3-mm straight wire guide was introduced, through retrograde approach, until the proximal extremity of femur was reached. Femurs were assessed for posterosuperior and anterosuperior portions of major trochanter, pear-shaped cavity, and upper median line between the head-neck and the major trochanter. Results: in 62%, the straight wire guides exited at the anterior surface of major trochanter. In the pear-shaped cavity, the median distance found was 1.0 cm and the interquartile range was 0.5 cm, initially expressing, in relation to pear-shaped cavity, better accuracy. Conclusion: the central axis of the medullar canal, at coronal plane, projected better accuracy in the region of the pear-shaped cavity.

Retrograde femoral nailing: an understanding of the intercondylar insertion site

BACKGROUND

: The intercondylar starting site for retrograde femoral nailing has been selected to avoid damage to the articular weight-bearing surface. This starting point assumes that implants will adapt to the femoral radius of curvature. Implant-femur radius mismatch may result in postoperative fracture angulations, translation, or increase in hoop stress.

METHODS

: Twenty cadaveric femurs were analyzed. The posterior cruciate ligament (PCL) was preserved. Two different femoral nails were analyzed. After creating an osteotomy at the superior level of the lesser trochanter, a cannulated nail was inserted to the level of the articular surface of the distal femur. A pointed guide wire was advanced through the nail and driven through the articular surface of the distal femur. The exact location of the guide wire exiting the articular surface was anatomically and radiographically determined.

RESULTS

: The mean anterior distance of the wire to the PCL was 20.4 mm for the ACE nail and 13.9 mm for the Synthes Femoral Nail (SFN). A Student's t test showed a significant difference between the two implants (p = 0.0002). The mean medial distance of the guide wire exit compared with the PCL was 4.2 mm for the ACE and 4.1 mm for the SFN nail and showed no significant difference.

CONCLUSIONS

: The tested nails require a more anterior insertion site than what has been described to match the femur curvature. Of the two nail designs evaluated, the SFN was more compatible with the currently recommended starting point.

Retrograde cement removal in periprosthetic fractures following hip arthroplasty

INTRODUCTION

Revision of cemented hip arthroplasty after periprosthetic fractures of the femur is a demanding procedure. Many different technical devices have been developed for this purpose. This paper presents a new surgical technique of cement removal avoiding excessive exposure of the fracture site.

MATERIALS AND METHODS

In six patients with periprosthetic fractures of the femur following hip arthroplasty (Johansson Type II and III) cement removal was performed by means of advancing a retrograde nail through the intercondylar notch of the knee.

RESULTS

In all cases the cement was removed completely. Intraoperative complications or significant knee problems were not observed.

CONCLUSION

The intracondylar approach provides a simple, rapid and less invasive technique for cement removal in revision hip arthroplasty.