Identification of the Optimal Intercondylar Starting Point for Retrograde Femoral Nailing: An Anatomic Study

Posterior Cruciate Ligament Injury After Retrograde Nailing of Periprosthetic Distal Femur Fractures: A Report of 2 Cases

CASE

A 51-year-old man and 64-year-old woman with bilateral cruciate-retaining total knee arthroplasties (CR-TKAs) who sustained unilateral periprosthetic distal femur fractures above their CR-TKA and experienced knee instability secondary to an iatrogenic posterior-cruciate-ligament (posterior cruciate ligament [PCL]) injury from retrograde intramedullary nailing. Both patients recovered knee stability after undergoing revision surgery.

CONCLUSION

Many CR-TKA designs have sufficient medial-lateral intercondylar distance to place a retrograde nail, femoral components with a relatively posterior transition from the trochlear groove to the intercondylar box will necessitate a nail starting point closer to the PCL origin. This may contribute to iatrogenic postoperative knee instability for patients with CR-TKA designs.

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.

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.

The geriatric distal femur fracture: nail, plate or both?

Surgical fixation of distal femur fractures in geriatric patients is an evolving topic. Unlike hip fractures, treatment strategies for distal femur fractures are ill-defined and lack substantive high-quality evidence. With an increasing incidence and an association with significant morbidity and mortality, it is essential to understand existing treatment options and their supporting evidence. Current fixation methods include the use of either retrograde intramedullary nails, or plate and screw constructs. Due to the variability in fracture patterns, the unique anatomy of the distal femur, and the presence or absence or pre-existing implants, decision-making as to which method to use can be challenging. Recent literature has sought to describe the advantages and disadvantages of each, however, there is currently no consensus on a standard of care, and little randomized evidence is available that directly compares intramedullary nails with plating. Future randomized studies comparing intramedullary nails with plating constructs are necessary in order to develop a standard of care based on injury characteristics.

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.

The use of 'blocking' screws for the 'closed' reduction of difficult proximal and distal femoral fractures

Most meta-diaphyseal femoral fractures that are treated with intramedullary nailing can be reduced satisfactorily by skeletal traction without ‘opening’ the fracture site and therefore, complications such as nonunion, infection and wound healing problems are reduced.

In cases where adequate fracture reduction cannot be achieved by skeletal traction, ‘reduction aids’ have been used during the operative procedure in order to avoid the exposure of the fracture site.

The ‘blocking’ screw, as a reduction tool, was proposed initially for the ‘difficult’ metaphyseal fractures of the tibia. Subsequently, surgeons have tried to implement the ‘blocking’ screw technique in ‘difficult’ distal femoral fractures.

This article presents the ‘blocking’ screw technique as an adjunctive process in the management of fractures of the proximal and distal femur which are found to be non-reducible by skeletal traction alone. The minimal invasiveness of the technique contributes greatly to the preservation of both the soft tissue integrity and the fracture haematoma and thus reduces the major complications that can occur by exposing the fracture site.

Cite this article: EFORT Open Rev 2021;6:451-458. DOI: 10.1302/2058-5241.6.210024

Osteoporotic distal femur fractures in the elderly: peculiarities and treatment strategies

Distal femur fractures account for 4-6% of osteoporosis related fractures of the femur in the elderly population. They represent a relevant cause of morbidity and mortality in the geriatric population with a reported 1-year mortality reaching 30%. Non-displaced fractures or even displaced fractures in patients with high operative risk can be treated conservatively. However, operative treatment is the most widely accepted management option for displaced fractures. The advantage resides in early mobilization and weight-bearing, reducing risks related with a prolonged immobilization when compared with conservative treatment. On the other hand, the intrinsic difficulty of fixing an osteoporotic bone is a major concern. The presence of osteosynthesis devices or prosthetic implants in the femur can make the surgical treatment more challenging, sometimes limiting therapeutic options. Aim of the present paper is to review the most recent literature about osteoporotic distal femur fractures in the elderly, including periprosthetic and other hardware related fractures, to highlight current evidence on management options and related results as a guide for the daily clinical practice.

Optimal Starting Point for Fifth Metatarsal Zone II Fractures: A Cadaveric Study

BACKGROUND

Identifying the optimal starting point for intramedullary fixation of tibia and femur fractures is well described in the literature using a retrograde or anterograde technique. This technique has not been applied to the fifth metatarsal, where screw trajectory can cause iatrogenic malreduction. The generally accepted starting point for the fifth metatarsal is "high and inside" to accommodate the fifth metatarsal's dorsal apex and medial curvature. We used a retrograde technique to identify the optimal starting position for intramedullary fixation of fifth metatarsal fractures.

METHODS

Five matched cadaveric lower extremity pairs were dissected to the fifth metatarsal neck. An osteotomy was made to access the intramedullary canal. A retrograde reamer was passed to the base of the fifth metatarsal to ascertain the ideal entry point. Distances from each major structure on the lateral aspect of the foot were measured. Computed tomography scans helped assess base edge measurements.

RESULTS

In 6 of 10 specimens, the retrograde reamer hit the cuboid with a cuboid invasion averaging 0.7 mm. The peroneus brevis and longus were closest to the starting position with an average distance of 5.1 mm and 5.7 mm, respectively. Distances from the entry point to the dorsal, plantar, medial, and lateral edges of the metatarsal base were 8.3 mm, 6.9 mm, 9.7 mm, and 9.7 mm, respectively.

CONCLUSION

Optimal starting position was found to be essentially at the center of the base of the fifth metatarsal at the lateral margin of the cartilage. Osteoplasty of the cuboid or forefoot adduction may be required to gain access to this site.

CLINICAL RELEVANCE

This study evaluated the ideal starting position for screw placement of zone II base of the fifth metatarsal fractures, which should be considered when performing internal fixation for these fractures.

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.

[Distal femoral fractures]

Fractures of the distal femur still represent injuries that are difficult to treat as they either affect younger patients after a high-energy trauma with soft tissue damage and osseous comminution or elderly people with impaired local vascularity and a poor bone stock. However, exactly these fractures profit from new, biological principles of treatment, which help to diminish additional surgical trauma by indirect fracture reduction and insertion of stabilizing implants via mini-incisions. Basically, these techniques are represented by retrograde intramedullary nails and submuscularilly inserted plates/internal fixateurs. While intramedullary nails are well suited to fix extramedullary and simple articular fractures (C1), plates can also be used to treat complex articular fractures. Nevertheless, any displaced articular fracture component must still be anatomically reduced by an open approach and fixed with absolute stability. Technical advances as well as demographic changes will continue to represent challenges in the treatment of these fractures.

Outcome analysis of retrograde nailing and less invasive stabilization system in distal femoral fractures: A retrospective analysis

BACKGROUND

TWO MAJOR THERAPEUTIC PRINCIPLES CAN BE EMPLOYED FOR THE TREATMENT OF DISTAL FEMORAL FRACTURES: retrograde intramedullary (IM) nailing (RN) or less invasive stabilization on system (LISS). Both operative stabilizing systems follow the principle of biological osteosynthesis. IM nailing protects the soft-tissue envelope due to its minimally invasive approach and closed reduction techniques better than distal femoral locked plating. The purpose of this study was to evaluate and compare outcome of distal femur fracture stabilization using RN or LISS techniques.

MATERIALS AND METHODS

In a retrospective study from 2003 to 2008, we analyzed 115 patients with distal femur fracture who had been treated by retrograde IM nailing (59 patients) or LISS plating (56 patients). In the two cohort groups, mean age was 54 years (17-89 years). Mechanism of injury was high energy impact in 57% (53% RN, 67% LISS) and low-energy injury in 43% (47% RN, 33% LISS), respectively. Fractures were classified according to AO classification: there were 52 type A fractures (RN 31, LISS 21) and 63 type C fractures (RN 28, LISS 35); 32% (RN) and 56% (LISS) were open and 68% (RN) and 44% (LISS) were closed fractures, respectively. Functional and radiological outcome was assessed.

RESULTS

Clinical and radiographic evaluation demonstrated osseous healing within 6 months following RN and following LISS plating in over 90% of patients. However, no statistically significant differences were found for the parameters time to osseous healing, rate of nonunion, and postoperative complications. The following complications were treated: hematoma formation (one patient RN and three patients LISS), superficial infection (one patient RN and three patients LISS), deep infection (2 patients LISS). Additional secondary bone grafting for successful healing 3 months after the primary operation was required in four patients in the RN (7% of patients) and six in the LISS group (10% of patients). Accumulative result of functional outcome using the Knee and Osteoarthritis Outcome (KOOS) score demonstrated in type A fractures a score of 263 (RN) and 260 (LISS), and in type C fractures 257 (RN) and 218 (LISS). Differences between groups for type A were statistically insignificant, statistical analysis for type C fractures between the two groups are not possible, since in type C2 and C3 fractures only LISS plating was performed.

CONCLUSION

Both retrograde IM nailing and angular stable plating are adequate treatment options for distal femur fractures. Locked plating can be used for all distal femur fractures including complex type C fractures, periprosthetic fractures, as well as osteoporotic fractures. IM nailing provides favorable stability and can be successfully implanted in bilateral or multisegmental fractures of the lower extremity as well as in extra-articular fractures. However, both systems require precise preoperative planning and advanced surgical experience to reduce the risk of revision surgery. Clinical outcome largely depends on surgical technique rather than on the choice of implant.

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.

Distal third femur fractures treated with retrograde femoral nailing and blocking screws

Retrograde femoral nailing is a widely used treatment for fractures involving the distal third of the femur. Angular malunion of these fractures after retrograde intramedullary nailing is a known complication. We report our surgical technique and experience using blocking screws to aid in reduction and augment the stability of the fixation when using a retrograde intramedullary nail for distal femoral 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.

Femoral supracondylar malunions with varus medial condyle and shortening

Femoral supracondylar malunions associated with varus deformity of the medial femoral condyle and shortening are rare, and all techniques for treatment of this complication reported to date have limitations. A one-stage antegrade locked intramedullary nailing technique to concomitantly treat these combined disorders was performed in 19 consecutive patients. The following procedures were performed: removal of previous implants, supracondylar corrective osteotomy, one-stage lengthening on a fracture table, antegrade static locked intramedullary nail stabilization, and corticocancellous bone grafting. Seventeen patients with malunions received regular followup for a median of 2.4 years (range, 1.1-5.2 years). Sixteen malunions healed with a union rate of 94.1% (16 patients) and a median union period of 4.5 months (range, 3-7 months). Only one nonunion associated with nail breakage occurred (5.9%; one patient) and one deep infection recurred (5.9%; one patient). Both patients recovered after appropriate treatment. All patients had improved knee alignment and function. Antegrade locked intramedullary nailing is an effective technique for one-stage treatment of combined disorders in patients with femoral supracondylar malunions. Complications can be avoided if patients and surgeons are careful during the treatment course. Protected weightbearing until fracture healing is crucial to successful treatment.