MRI Can Detect “Invisible” Femoral Neck Fractures in Patients with Shaft Fractures
For more than 40 years, orthopaedic trauma surgeons have been interested in this fairly common fracture combination, which is often seen in polytrauma patients. We have long hypothesized that much of the energy that fractures the femoral shaft is dissipated, leaving many ipsilateral neck fractures nondisplaced and difficult to recognize on plain radiographs.
But the consequences of missing a femoral neck fracture can be devastating. For example, because the neck fracture pattern is often vertical (Pauwels type III), the risk of displacing the neck fracture during intramedullary nailing is very high. Achieving reduction and fixation of a displaced neck fracture near an intramedullary nail—either intraoperatively or postoperatively—is extremely challenging.
Because of these issues, some authors recommend a thin-cut CT series to identify nondisplaced ipsilateral neck fractures preoperatively, and this protocol has been shown to significantly reduce the delay in identifying such fractures. In the February 19, 2020 issue of The Journal, Rogers et al. from UTHealth in Houston show that even with thin-cut CT, the crack can be missed. These authors added to the protocol limited-sequence MRI that identifies these fractures with very high sensitivity and takes <10 minutes to perform.
In this study, among 39 acute, high-energy femoral shaft fractures, the authors identified 4 ipsilateral neck fractures with MRI that were not seen on CT. Despite exhibiting polytrauma, 89% of all indicated patients in this study were evaluated preoperatively with the limited-sequence MRI protocol, including those in traction and those treated initially with external fixation.
The findings from this study should prompt trauma surgeons practicing in high-volume centers to develop similar MRI protocols. It may also be possible to develop such protocols in lower-volume centers, but in those settings it is especially incumbent on the surgical team to recognize that this fracture combination occurs in a fairly high percentage of cases and to carefully scrutinize plain radiographs and consider thin-cut CT scanning of the ipsilateral hip. In addition, the potential for an ipsilateral nondisplaced femoral neck fracture should trigger increased use of fluoroscopy during intramedullary nailing of shaft fractures, so that concomitant neck fractures can be recognized and stabilized with screws before they become displaced.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
The Evolution of Orthopaedic Surgical Skills Simulation
Surgical skills education in orthopaedics has changed dramatically from the “see one, do one, teach one” process of 30 years ago. These changes have come with a greater degree of supervision and formal skills assessments, and they have been aided by the visionary leadership at the Accreditation Council for Graduate Medical Education (ACGME) and our own orthopaedic Residency Review Committee. These skill-acquisition enhancements have benefited both our trainees and the patients we collectively care for.
A decade ago, we entered a new phase of skill development and enhancement with computer-based surgical simulators. With advances in software and widespread interest across North America in goal-driven learning through simulation, great progress has been made. In the November 20, 2019 issue of JBJS, Weber et al. report on the further validation of a surgical simulator focused specifically on percutaneous, fluoroscopically guided pin placement for femoral neck fractures. The simulator was developed in partnership between the AAOS and OTA.
This study sought to determine whether novice practitioners (medical students, in this case) who completed 9 training modules before using the simulator (the “trained” group) would perform the simulated pinning task better than peers who did not complete the presimulation training (the “untrained” group). It was no surprise to me that the trained group had a significantly higher overall performance score on the simulator. In addition, relative to the untrained group, the trained students also showed improved performance on 4 specific measures—3 of which were related to the angle between the placed pins.
These findings are clearly supportive of continued development of this and additional simulation environments. But at the same time, we need to move forward with improved documentation of surgical skill acquisition among orthopaedic residents and fellows. As simulator technology continues to improve, the next decade should yield even more positive results in skills acquisition than we saw in the last decade. We are clearly on the right path with the use of advanced technology for surgical skill development among orthopaedic trainees.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Hemi vs THA Findings Helpful, But Not Practice-Changing
OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent study in The New England Journal of Medicine, the following commentary comes from Paul E. Matuszewski, MD.
A recent issue of The New England Journal of Medicine published the results from a large, multicenter randomized trial comparing the outcomes of hemiarthroplasty versus total hip arthroplasty (THA) to treat displaced femoral neck fractures in ambulatory adults.
The HEALTH investigators enrolled 1,495 patients in the study, and 85.1% of those patients had complete data for analysis after 2 years. The researchers found no significant differences between the groups with regard to the primary outcome—secondary hip procedures (7.9% in the THA group vs 8.3% in the hemi group). The risk of secondary hip procedures during the first year was higher in the THA group, but the hemiarthroplasty group had a higher risk of secondary procedures in the second year. Open/closed reductions of hip dislocations were the most common secondary procedures among the THA group, and revision to THA was the most common secondary procedure in the hemiarthroplasty group. The THA group had slightly better WOMAC scores, but the difference was not within a clinically significant range. There were no between-group differences noted in other patient-reported outcomes.
The HEALTH investigators followed these patients for only two years, which is notably the standard for many orthopaedic studies, but this short follow-up limits the practical application of these findings. The authors note that after the first year, primary THA was favorable with regard to secondary hip procedures. It is reasonable to think that this difference may become more compelling beyond 2 years, as more patients who received hemiarthroplasty are likely to be converted to THA.
The suggestion that there may not be an early benefit of THA over hemiarthroplasty in the ambulatory adult with a displaced femoral neck fracture contrasts with current recommendations from the American Academy of Orthopaedic Surgeons. However, the 2-year follow-up of this trial represents only a “snapshot” of the continuum of outcomes from these two hip-fracture treatments. The findings may add to our understanding of what our patients can expect during the first 2 years following these procedures, but I would caution surgeons against making any drastic changes to their current practice in response to this data.
Paul E. Matuszewski, MD is the Director of Orthopaedic Trauma Research and Assistant Professor of Orthopaedic Traumatology at the University of Kentucky.
Nondisplaced Femoral Neck Fractures in the Elderly: Minimizing Complications
Trying to educate elderly patients and their family members about how to best treat a femoral neck fracture can be difficult. These patients typically have multiple—and often severe—medical comorbidities that can make even the most “simple” surgery complex and life-threatening. Making such discussions even harder is the lack of Level-I evidence related to treating these common injuries. For severely displaced fractures, the evidence supports performing either a hemi- or total hip arthroplasty on most patients. But the data is much less clear for minimally or nondisplaced fractures.
For these reasons, I was excited to read the study by Dolatowski et al. in the January 16, 2019 issue of JBJS. The authors performed a prospective, randomized controlled trial comparing internal screw fixation to hemiarthroplasty for valgus impacted or nondisplaced femoral neck fractures in >200 patients with a mean age of 83 years. They found that patients who underwent hemiarthroplasty had a significantly faster “up-and-go” test and were significantly less likely to undergo a major reoperation than those who underwent internal fixation. However, patients in the internal-fixation group were less likely to develop pulmonary complications. There were no between-group differences in overall hip function (as evaluated with the Harris hip score) or in the 24-month mortality rate.
This study lends support to what many surgeons tell elderly patients with a nondisplaced femoral neck fracture: a hemi- (or total) arthroplasty will probably provide the lowest risk of needing a repeat operation for the injury, while placing percutaneous screws may decrease the risk of cardiopulmonary complications related to the operation. While these findings may not be surprising, this study provides important Level I data that can help us educate patients and their families so that the best treatment for each individual patient can be determined.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Predicting Failure of Femoral Neck Fixation
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Matthew Herring, MD, in response to a recent study in the Journal of Orthopaedic Trauma.
With many problems in orthopaedics, the best management options are still being debated. The treatment of femoral neck fractures is one such problem. Surgeons have several available options: cancellous screws (CS), a sliding hip screw (SHS), hemiarthroplasty, and total hip arthroplasty. The recently completed Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) randomized trial sought to offer insight on those treatment modalities.1 The study enrolled 1,079 patients with low-energy femoral neck fractures and randomized them into treatment with CS or SHS.
In a follow-up study published in the May 2018 edition of the Journal of Orthopedic Trauma, Sprague et al. analyzed FAITH data to identify predictors of revision surgery during 24 months after surgical fixation of a femoral neck fracture.2 Based on previously published studies, the authors identified 15 factors a priori that may be associated with revision surgery . Among the more than 800 patients in the FAITH cohort who had complete follow-up data, 191 (23%) underwent revision surgery and were included in the analysis. Proportional hazard modeling identified 5 factors associated with revision surgery: female sex (hazard ratio [HR], 1.79), body mass index (HR, 1.19—a 19% increased risk of revision for every 5-point increase in BMI), displaced fracture (HR, 2.16), Pauwels type III configuration (HR, 2.13 relative to type II), and poor implant positioning (HR, 2.70). In addition, prefracture dependence on assistive devices for ambulation was significantly associated with a risk of conversion to arthroplasty (p = 0.04), although a hazard ratio was not reported.
These important findings may help guide our decision making for the treatment of femoral neck fractures. First, male patients may be better candidates for surgical fixation of neck fractures than female patients, which probably relates to sex differences in bone density. Thinner patients also may be better candidates for femoral neck fixation, while arthroplasty may be the more reliable option for high-BMI patients.
Second, we have to pick the right fractures to fix. As is well described elsewhere in the literature, a more vertical fracture line (>50°) is more likely to fail with fixation. Additionally, patients with displaced fractures face a significantly higher risk of revision surgery and may be poor candidates for fixation.
Arguably, the most important modifiable risk factor for revision surgery is surgical technique. Unfortunately (and fortunately), in the FAITH study there were too few malreductions to investigate this variable in detail. However, poor implant positioning—defined as prominent screws at the lateral cortex, screw penetration, and lag screws positioned too high—was strongly associated with an increased risk of revision surgery.
It goes without saying, but well-placed implants perform better.
Matthew Herring, MD is a senior orthopaedic resident at the University of Minnesota and a member of the JBJS Social Media Advisory Board.
References
- Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) Investigators. Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial. Lancet. 2017;389(10078):1519-1527.
- Sprague S, Schemitsch EH, Swiontkowski M, et al. Factors Associated With Revision Surgery After Internal Fixation of Hip Fractures. J Orthop Trauma. 2018;32(5):223-230.
JBJS Editor’s Choice: How Best to Treat Femoral Neck Fractures in Younger Adults
In the January 4, 2017 issue of The Journal, Swart et al. provide a well-done Markov decision analysis on the cost effectiveness of three treatment options for femoral neck fractures in patients between the age of 40 and 65: open reduction and internal fixation (ORIF), total hip arthroplasty (THA), and hemiarthroplasty. Plugging the best data available from the current orthopaedic literature into their model, the authors estimated the threshold age above which THA would be the superior strategy in this relatively young population.
For patients in this age group, traditional thinking has been to perform ORIF in order to “save” the patient’s native hip and avoid the likelihood of later revision arthroplasty. However, in this analysis THA emerges as a cost-effective option in otherwise healthy patients >54 years old, in patients >47 years old with mild comorbidity, and in patients >44 years old with multiple comorbidities.
On average, both THA and ORIF have similar outcomes across the age range analyzed. But ORIF with successful fracture healing yields slightly better outcomes and considerably lower costs than THA, whereas patients whose fracture does not heal with ORIF have notably worse outcomes than THA patients. This finding supports my personal bias that anatomical reduction and biomechanically sound fixation must be achieved in this younger population with displaced femoral neck fractures. The analysis confirmed that, because of poor functional outcomes with hemiarthroplasty in this population, hemiarthroplasty should not be considered. Poor hemiarthroplasty outcomes are likely related to the mismatch between the metal femoral head and the native acetabular cartilage, leading to fairly rapid loss of the articular cartilage and subsequent need for revision.
This analysis by Swart et al. provides very valuable data to discuss with younger patients and families when engaging in shared decision making about treating an acute femoral neck fracture. In my experience, most patients in this age group prefer to “keep” their own hip whenever possible, which puts the onus on the surgeon to gain anatomic reduction and biomechanically sound fixation with ORIF.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
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