Low reoperation rate after fixation of displaced femoral neck fractures with the femoral neck system (FNS).

PURPOSE: Operative fixation of femoral neck fractures (FNFs) remains challenging. Complications are not infrequent, especially in displaced patterns. Numerous fixation techniques have been previously described in the literature; however, there remains a paucity of data regarding outcomes of these injuries treated with the femoral neck system (FNS). METHODS: Patients with a displaced FNF (OTA/AO 31B) treated with the FNS at a single level 1 academic trauma center between 1/1/2019 and 1/1/2023 were identified. Radiographs were reviewed to assess fracture displacement, location, and characteristics. Patient records were further reviewed to assess for complications, reoperations, and osseous union. RESULTS: Forty-three patients (65% male) with 44 FNFs were identified with a mean age of 35.0 years (range, 13-61 years). Two patients developed a deep infection requiring surgical debridement, four patients underwent a total hip arthroplasty, and one patient underwent a valgus intertrochanteric osteotomy for nonunion. There were three cases of femoral head AVN. Mean follow-up was 482.5 days among all patients, and 36 fractures had at least 6 months of follow-up or reached bony union. CONCLUSIONS: Here, we present a series of patients treated with the FNS for internal fixation and report a 18% reoperation rate. This is lower than the average rate that has been previously reported in similar patient populations in the literature treated with alternative methods of internal fixation. Thus, the FNS appears to be a safe and effective option for treatment of these injuries.

Does local fat thickness correlate with post-operative infection in open reduction and internal fixation of acetabulum fractures?

PURPOSE: Obesity is an epidemic which increases risk of many surgical procedures. Previous studies in spine and hip arthroplasty have shown that fat thickness measured on preoperative imaging may be as or more reliable in assessment of risk of post-operative infection and/or wound complications than body mass index (BMI). We hypothesized that, similarly, increased local fat thickness at the surgical site is a predictor of wound complication in acetabulum fracture surgery. METHODS: Patients who underwent open reduction and internal fixation (ORIF) of an acetabulum fracture through a Kocher-Langenbeck (K-L) approach at a single institution from 2013 to 2020 were identified. Pre-operative CT scans were used to measure fat thickness from the skin to the greater trochanter in line with the surgical approach. Post-operative infections and wound complications were recorded and associated with fat thickness and BMI. RESULTS: 238 patients met inclusion criteria. 12 patients had either infection or a wound complication (5.0%). There was no significant association with BMI or preoperative fat thickness on post-operative infection or wound complication (p-value 0.73 and 0.86). CONCLUSIONS: There is no statistically significant association of post-operative infection or wound complications in patients with increased soft tissue thickness or increased BMI. ORIF of acetabulum fractures through a K-L approach can be performed safely in patients with large subcutaneous fat thickness and high BMI with low risk of infection or wound complications.

Bladder Repair With Irrigation and Debridement and Open Reduction Internal Fixation of the Anterior Pelvic Ring Is Safe and Decreases Risk of Infection in Pelvic Ring Injuries With Extraperitoneal Bladder Ruptures.

OBJECTIVES: To determine the incidence of infection in nonoperative versus operative management of extraperitoneal bladder ruptures in patients with pelvic ring injuries. DESIGN: A retrospective cohort study of 2 prospectively collected trauma registries. SETTING: Two Level 1 trauma centers. PATIENT SELECTION CRITERIA: Patients with operative pelvic ring injuries, 68 (6%) had extraperitoneal bladder ruptures. OUTCOME MEASURES AND COMPARISONS: The primary outcome was the incidence and associated risk factors of deep pelvic infection requiring return to OR for surgical debridement. Secondary outcomes included quality of reduction, other complications, and radiographic union. Comparisons were made based on the status of any associated bladder injury. RESULTS: Of 1127 patients with operative pelvic ring injuries, 68 patients had extraperitoneal bladder ruptures, 55 had bladder repair and 13 did not. Of those 13 without repair, none had ORIF of the anterior pelvic ring. Patients without bladder repair had an increased odds of infection 17-fold compared to patients who did have a repair performed (OR 16.9, 95% CI 1.75 - 164, P = 0.01). Other associated factors for deep pelvic infection included use of suprapubic catheter ( p < 0.02) and a closed reduction of the anterior ring ( p < 0.01). Patients undergoing anterior ring ORIF and bladder repair had improved reductions and no increased infection risk. CONCLUSIONS: Operative repair of extraperitoneal bladder ruptures decreases risk of infection in patients with pelvic ring injuries. Additionally, ORIF of the anterior pelvic ring does not increase the risk of infection and results in better reductions compared to closed reduction. Treatment algorithms for these combined injuries should consider recommending early bladder repair and anterior pelvic ORIF. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Percutaneous sacral screw fixation alone sufficient for mildly displaced U-type sacral fractures with preserved osseous fixation pathways.

PURPOSE: To describe U-type sacral fracture characteristics amenable to percutaneous sacral screw fixation. METHODS: U-type sacral fractures were identified from a trauma registry at a level 1 trauma center from 2014 to 2020. Patient demographics, injury mechanism, fracture characteristics, and fixation construct were retrospectively retrieved. Associations between fracture pattern and surgical fixation were identified. RESULTS: 82 U-type sacral fractures were reviewed. Six treated with lumbopelvic fixation (LPF) and 76 were treated with percutaneous sacral screws (PSS) alone. Patients receiving LBF had greater sacral fracture displacement in coronal, sagittal, and axial planes compared to patients receiving PSS alone (P < 0.05), negating osseous fixation pathways. All patients went onto sacral union and there were no implant failures or unplanned reoperations for either group. CONCLUSION: If osseous fixation pathways are present, U-type sacral fractures can be successfully treated with percutaneous sacral screws. LPF may be indicated in more displaced fractures with loss of spinopelvic alignment. Both techniques for U-type sacral fractures result in reliable fixation and healing without reoperations.

Use of 3D Fluoroscopy to Assist in the Reduction and Fixation of Pelvic and Acetabular Fractures: A Safety and Quality Case Series.

SUMMARY: Multidimensional fluoroscopy has been increasingly used in orthopaedic trauma to improve the intraoperative assessment of articular reductions and implant placement. Owing to the complex osteology of the pelvis, cross-sectional imaging is imperative for accurate evaluation of pelvic ring and acetabular injuries both preoperatively and intraoperatively. The continued development of fluoroscopic technology over the past decade has resulted in improved ease of intraoperative multidimensional fluoroscopy use in pelvic and acetabular surgery. This has provided orthopaedic trauma surgeons with a valuable tool to better evaluate reduction and fixation at different stages during operative treatment of these injuries. Specifically, intraoperative 3D fluoroscopy during treatment of acetabulum and pelvis injuries assists with guiding intraoperative decisions, assessing reductions, ensuring implant safety, and confirming appropriate fixation. We outline the useful aspects of this technology during pelvic and acetabular surgery and report its utility with a consecutive case series at a single institution. The added benefits of this technology have improved the ability to effectively manage patients with pelvis and acetabulum injuries.

Oblique anterior pelvic external fixator for intraoperative reduction of rotationally unstable pelvic ring injuries.

Incomplete sacroiliac joint injuries are often associated with external rotation and extension deformities on the injured hemipelvis. To appropriately correct this deformity, an oblique reduction force from caudal to cranial and lateral to medial is helpful. These injuries are often associated with traumatic disruption of the pubic symphysis. However, in injuries without traumatic disruption to the pubic symphysis, a two-pin oblique anterior external fixator can be used to obtain and maintain reduction of the sacroiliac joint, while percutaneous fixation is subsequently placed. Through a small case series and three specific patient examples, we demonstrate that the oblique anterior external fixator frame is a simple and effective strategy with the reduction and stabilization process of these multiplanar hemipelvis deformities.

Imaging of Pelvic and Acetabular Trauma: Part 2, Soft-Tissue Findings.

Pelvic ring injuries and acetabular fractures can be complex and challenging to treat. Orthopaedic trauma surgeons scrutinize pelvic radiographs and accompanying CT images for the osseous details that help create a thorough patient-specific preoperative plan. While the osseous details are incredibly important, the surrounding soft-tissue structures are equally as critical and can have a tremendous effect on both the patient and the surgeon. These findings may change surgery timing, dictate the need for additional surgeons or multidisciplinary teams, and determine the treatment sequence. The structures and potential clinical findings reviewed and demonstrated through example images should be sought out during physical examination and correlative preoperative imaging review. Combining all the available osseous and nonosseous information with a detailed approach helps the surgeon predict potential pitfalls and adjust surgical plans before incision. Maximizing the accuracy of the preoperative planning process can streamline treatment algorithm development and ultimately contribute to the best possible clinical patient outcome.

Imaging of Pelvic and Acetabular Trauma: Part 1, Osseous Findings.

Pelvic ring injuries and acetabular fractures are complex injuries and are often challenging to treat for a number of reasons. Orthopaedic trauma surgeons critically evaluate pelvic radiographs and CT images to generate an appropriate detailed injury and patient-specific preoperative plan. There are numerous crucial osseous details that surgeons should be aware of. Often, some of the most important factors that affect patients in treatment timing decisions, assessing reduction strategies, and deciding and inserting fixation constructs may be subtle on preoperative imaging. The radiographic and CT imaging findings covered subsequently should be sought out and appreciated preoperatively. Combining all the available osseous information helps the surgeon predict potential pitfalls and adjust surgical plans before incision. Ensuring a methodical and meticulous imaging review allows for the development of a detailed preoperative plan and helps avoid intraoperative missteps. This process will inherently streamline the surgical procedure and optimize the patient's surgical care. Maximizing the accuracy of the preoperative planning process can streamline the treatment algorithm and ultimately contribute to the best possible clinical outcome.

Assessment of sacral osseous fixation pathways for same-level dual transiliac-transsacral screw insertion.

INTRODUCTION: The purpose of this study is to (1) describe a pre-operative planning technique using non-reformatted CT images for insertion of multiple transiliac-transsacral (TI-TS) screws at a single sacral level, (2) define the parameters of a sacral osseous fixation pathway (OFP) that will allow for insertion of two TI-TS screws at a single level, and (3) identify the incidence of sacral OFPs large enough for dual-screw insertion in a representative patient population. METHODS: Retrospective review at a level-1 academic trauma center of a cohort of patients with unstable pelvic injuries treated with two TI-TS screws in the same sacral OFP, and a control cohort of patients without pelvic injuries who had CT scans for other reasons. RESULTS: Thirty-nine patients had two TI-TS screws at S1. Eleven patients, all with dysmorphic osteology, had two TI-TS screws at S2. The average pathway size in the sagittal plane at the level the screws were placed was 17.2 mm in S1 vs 14.4 mm in S2 (p = 0.02). Twenty-one patients (42%) had screws that were intraosseous and 29 (58%) had part of a screw that was juxtaforaminal. No screws were extraosseous. The average OFP size of intraosseous screws was 18.1 mm vs. 15.5 mm for juxtaforaminal screws (p = 0.02). Fourteen millimeters was used as a guide for the lower limit of the OFP for safe dual-screw fixation. Overall, 30% of S1 or S2 pathways were ≥ 14 mm in the control group, with 58% of control patients having at least one of the S1 or S2 pathways ≥ 14 mm. CONCLUSIONS: OFPs ≥ 7.5 mm in the axial plane and 14 mm in the sagittal plane on non-reformatted CT images are large enough for dual-screw fixation at a single sacral level. Overall, 30% of S1 and S2 pathways were ≥ 14 mm and 58% of control patients had an available OFP in at least one sacral level.

Modified Lumbopelvic Technique Using S1 Pedicle Screws for Spinopelvic Dissociation U-Type and H-Type Sacral Fractures With Kyphotic Deformity.

SUMMARY: Spinopelvic dissociation injuries are complex injuries defined as discontinuity between the appendicular and axial skeleton. Fracture patterns are variable, but U-type and H-type fractures are common and often present with kyphotic deformity along with translational displacement and impaction. The ideal method of fixation has not been established for these injuries. The goals of treatment include restoration of alignment, stability, and neural decompression as needed. Traditional methods of lumbopelvic fixation have spanned the upper sacral fracture site. Our novel modified method of lumbopelvic fixation directly instruments the S1 body. This allows for direct manipulation of the fracture which we theorize improves reduction and increases stability across the fracture. This article characterizes the injury patterns, outlines the modified technique, and reports the clinical and radiographic outcomes of our modified lumbopelvic fixation technique and construct.

Superior gluteal artery injury risk from third sacral segment transsacral screw insertion.

OBJECTIVES: Iliosacral (IS) and transsacral (TS) screws are commonly used to stabilize pelvic ring injuries. The course of the superior gluteal artery (SGA) can be close to implant insertion paths. The third sacral segment (S3) has been described as a viable osseous fixation pathway (OFP) but the proximity of the SGA to the S3 screw path is unknown. METHODS: Fifty uninjured patients with contrasted pelvic computed tomograms (CTA) were identified with an S3 path large enough for a 7.0 mm TS screw. Starting sites for S1 IS or TS, S2 and S3 TS screws were located on the volume rendered lateral CTA image and transferred onto the surface rendered 3D CTA with the SGA clearly visible. The distance from screw start sites to the SGA was measured. A distance less than 3.5 mm was considered likely for injury. RESULTS: The average distances from screw start sites to the SGA were 23.0 ± 7.9 mm for S1 IS screws, 14.3 ± 6.4 mm for S2 TS screws and 25.9 ± 6.5 mm for S3 TS screws. No S1 IS screws, 5 S2 TS screws (10%), and no S3 TS screws were projected to cause injury to the SGA. CONCLUSIONS: The osseous start site and soft tissue path for an S3 TS screw is remote from the SGA. The S1 IS and S3 TS pathways are further away from the SGA while the S2 TS pathway is closer and may theoretically pose a higher injury risk in patients with an available S3 OFP.

Sciatic Nerve Entrapment and Transection in a Combined Pelvic Ring-Acetabular Fracture: A Case Report.

CASE: A traumatic sciatic nerve entrapment and transection because of a combined pelvic ring injury and acetabular fracture has never previously been described. We report such a case of a 32-year-old man who was found intraoperatively to have entrapment and transection of the sciatic nerve within the acetabular fracture. CONCLUSION: Consideration for urgent intervention should be given to patients who present with a sciatic nerve palsy in the setting of certain acetabular fracture patterns with residual posterior column displacement. Early recognition and intervention with neurolysis may help provide the best environment for recovery.

Posterior pelvic ring bone density with implications for percutaneous screw fixation.

BACKGROUND: Although the second (S2) and third (S3) sacral segments have been established as potential osseous fixation pathways for screw fixation, the S2 body has been demonstrated to have inferior bone density when compared to the body of the first (S1) sacral segment. Caution regarding the use of iliosacral screws at this level has been advised as a result. As transiliac-transsacral screws traverse the lateral cortices of the posterior pelvis, they may be relying on bone with superior density for purchase, which could obviate this concern. The objective of this study was to compare the bone density of the posterior ilium and sacroiliac joint to that of the sacral body at the first (S1), second (S2), and third (S3) sacral levels. MATERIALS AND METHODS: A retrospective case series was performed, reviewing the CT scans of 100 patients without prior pelvic trauma. Each CT was confirmed to have available osseous fixation pathways at the first (S1), second (S2), and third (S3) sacral segments. The bone density of the posterior ilium/sacroiliac joint (PISJ) and sacral body (SB) was measured using the embedded standardized Hounsfield units (HU) tool at each sacral level. RESULTS: The average S2 PISJ bone density (320.1) was significantly higher than the S1 (286.5) and S3 (278.9) PISJ (p < 0.0001) and S1 and S3 PISJ was not statistically different. The S1 sacral body bone density (231.1) was significantly higher than the S2 (182.1) and S3 (126.8) bone density (p < 0.0001). The PISJ bone density is greater than the sacral body at every sacral level (p < 0.0001). CONCLUSION: The S2 PISJ bone density is significantly greater than S1. The S1, S2, and S3 PISJ bone density is greater than the sacral body at all sacral levels, and the S1 body has higher bone density than the S2 and S3 bodies. These differences in bone density may have implications for the stability of posterior pelvic ring fixation constructs with regard to screw purchase. LEVEL OF EVIDENCE: Level III-Case cohort series.

Low Superior Pubic Ramus Screw Failure Rate With Combined Anterior and Posterior Pelvic Ring Fixation.

OBJECTIVES: To determine whether fracture pattern, implant size, fixation direction, or the amount of posterior pelvic ring fixation influences superior ramus medullary screw fixation failure. DESIGN: Retrospective cohort review. SETTING: Regional Level 1 trauma center. PATIENTS/PARTICIPANTS: After exclusion criteria, 95 patients with 111 superior ramus fractures with 3 months minimum follow-up were included. INTERVENTION: All patients underwent anterior and posterior pelvic ring fixation. MAIN OUTCOME MEASUREMENTS: Comparison of immediate postoperative radiographs and/or computer tomography scan with the latest postoperative image to calculate interval fracture displacement and implant position. Postoperative fracture displacement or implant position change greater than 1 cm were considered fixation failures. RESULTS: Five screws were defined as failures (4.5%), including 3 retrograde, 3 with bicortical fixation, 4 with a 4.5-mm screw, and 1 with a 7.0-mm screw. Fracture patterns included 2 oblique and 3 comminuted fractures. Based on the Nakatani classification, there were 3 zone II, 1 zone I, and 1 zone III. Failure modes included 3 with cut-out along the screw head and 1 cut-out and 1 cut-through at the screw tip. CONCLUSIONS: Our incidence of superior pubic ramus intramedullary screw fixation failure was 4.5%. Even with anterior and posterior fixation along with precise technique, failures still occur without a common failure predictor. The percutaneous advantages and proven strength provided by an intramedullary implant make it desirable to help reestablish global pelvic ring stability. Biomechanical and clinical studies are needed to further understand intramedullary superior ramus screw fixation. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Biomechanical Analysis of Retrograde Superior Ramus Screw Fixation Constructs.

OBJECTIVE: To investigate the biomechanical performance of different size and length retrograde superior ramus screws. MATERIALS AND METHODS: A vertical superior ramus fracture was created in osteoporotic composite hemipelvis bone models (Sawbones, Vashon Island, WA). After reduction, 4 fixation groups were created by inserting either a solid 4.5 mm (Depuy Synthes, Paoli, PA) or cannulated 7.0 mm screw (Zimmer, Warsaw, IN) of either 80 mm (short) or 140 mm (long) in length. An intact and an unstabilized osteotomy group were also created. Samples underwent cyclic loading for 5000 cycles with data acquisition at regular intervals. At the end of cyclic loading, load to failure was performed. RESULTS: The displacement after 5000 cycles for 4.5 mm short screws was significantly greater than 4.5 mm long and 7.0 mm short screws. At 5000 cycles, the 4.5-mm short screws had a significantly lower stiffness and lower load to failure than all other screws and were not different from the osteotomy model. CONCLUSIONS: Short 4.5-mm screws demonstrated increased displacement, lower stiffness, and decreased load to failure compared with all other screws. The biomechanical performance of 4.5-mm short screws was no different than unstabilized controls. Longer bicortical screw fixation is suggested when possible. Additional biomechanical and clinical studies are needed to fully understand the significance of these findings.

Novel resuscitation strategies in patients with a pelvic fracture.

Patients with a pelvic ring injury and hemodynamic instability can be challenging to manage with high rates of morbidity and mortality rates. Protocol-based resuscitation strategies are critical to successfully manage these potentially severely injured patients in a well-coordinated manner. While some aspects of treatment may vary slightly from institution to institution, it is critical to identify pelvic injuries and their associated injuries expediently. The first step at the scene of injury or in the trauma resuscitation bay should be the immediate application of a circumferential pelvic sheet or binder, initiation of physiologically optimal fluid resuscitation in the form 1:1:1 (pRBC:FFP:platelets) or whole blood, and to consider TXA as a safe adjunct to treat coagulopathy. Providers should have a very low threshold for emergent operative intervention in the form of pelvic external fixation and/or pelvic packing. This occurs in addition to simultaneous interventions addressing the other possible sources of bleeding in patients demonstrating signs of hemorrhagic shock and failure to respond to early resuscitation and external pelvic tamponade. Finally, while arterial injury is only present in a small percentage of patients with a pelvic ring injury, percutaneous vascular intervention with selective angiography and REBOA have been shown to be efficacious for patients with clinical indicators of arterial injury or who remain hemodynamically unstable despite external pelvic tamponade and packing to address venous bleeding. They should be performed when as early as possible for patients in true extremis limit further hemorrhage and allow resuscitation efforts to continue.

A Biomechanical Comparison of Trochanteric Versus Piriformis Reconstruction Nails for Femoral Neck Fracture Prophylaxis.

OBJECTIVES: To compare piriformis fossa to greater trochanteric entry cephalomedullary implants in an evaluation of femoral neck load to failure when the device is used for femoral shaft fractures with prophylaxis of an associated femoral neck fracture. METHODS: Thirty fourth-generation synthetic femur models were separated into 5 groups: intact femora, entry sites alone at the piriformis fossa or greater trochanter, and piriformis fossa and greater trochanteric entry sites after the insertion of a cephalomedullary nail. Each model was mechanically loaded with a flat plate against the superior femoral head along the mechanical axis and load to failure was recorded. RESULTS: Mean load to failure was 5487 ± 376 N in the intact femur, 3126 ± 387 N in the piriformis fossa entry site group, 3772 ± 558 N in the piriformis entry nail, 5332 ± 292 N for the greater trochanteric entry site, and 5406 ± 801 N for the greater trochanteric nail group. Both piriformis groups were significantly lower compared with the intact group. Both greater trochanteric groups were similar to the intact group and were statistically higher than the piriformis groups. CONCLUSIONS: A piriformis fossa entry site with or without an intramedullary implant weakens the femoral neck in load to failure testing. A greater trochanteric entry yields a load to failure equivalent to that of an intact femoral neck. Instrumentation with a greater trochanteric cephalomedullary nail is significantly stronger than a piriformis fossa cephalomedullary nail during axial loading in a composite femur model.

Dose-Area Product-to-Effective Dose Conversion Coefficients for Pelvic Radiography Using a Monte Carlo Program.

OBJECTIVE. The purpose of this study was to determine dose-area product-to-effective dose (DAP/E) conversion coefficients for a five-view pelvic radiograph series. DAP/E conversion coefficients may be used for radiation dose optimization when designing institutional protocols for pelvic trauma evaluation. MATERIALS AND METHODS. We conducted a retrospective record review of 25 patients at a level 1 trauma center who had sustained pelvic fractures and required a five-view pelvic radiograph series during workup. E values given in International Commission on Radiological Protection Publication 103 were simulated with a PC-based Monte Carlo program in conjunction with anthropomorphic phantoms adjusted on the basis of patient height and weight. Inputs included tube voltage (in kV), tube filtration (in millimeters of aluminum), anode angle, x-ray beam collimation, geometric distances, and angle of projection for each radiograph in the series. An incident polychromatic x-ray spectrum was generated and matched to the corresponding DAP values of each radiograph, and regression analysis was performed for the DAP/E conversion coefficients. RESULTS.E was strongly correlated with DAP independent from body mass index, with a mean global DAP/E conversion coefficient of 0.0125 mSv/dGy · cm2 for all radiographs (R2 = 0.95). Mean DAP/E conversion coefficients were 0.0133, 0.0110, 0.0143, 0.0113, and 0.0101 mSv/dGy · cm2 for anteroposterior, inlet, outlet, Judet left, and Judet right views, respectively (all R2 ≥ 0.94). CONCLUSION. DAP/E conversion coefficients are provided for a five-view pelvic radiograph series to allow reliable estimation of E. Measurement of cumulative E may affirm protocol design changes for the management of pelvic trauma.

Cortical Impaction in Posterior Wall Acetabular Fractures.

OBJECTIVES: To report the incidence of patients with extra-articular posterosuperior acetabular cortical impaction associated with a posterior wall acetabular fracture-dislocation. DESIGN: Retrospective case series. SETTING: Regional Level 1 trauma center. PATIENTS/PARTICIPANTS: Ninety-seven patients who sustained an isolated posterior wall acetabular fracture-dislocation from July 2007 until July 2017. INTERVENTION: The medical record and the computed tomography (CT) scan of the abdomen and pelvis were reviewed including axial, coronal, and sagittal reconstruction images and 3D surface renderings. MAIN OUTCOME MEASUREMENTS: Each pelvic CT scan was evaluated for impaction of the extra-articular posterosuperior acetabular cortical surface associated with posterior wall acetabular fracture-dislocations. The reduction accuracy was assessed for each patient with cortical impaction using postoperative CT scans. The final attending radiology report was reviewed to see whether the cortical impaction was noted. RESULTS: Four of the 99 patients (4.12%) had identifiable areas of cortical impaction on preoperative CT imaging. Reduction accuracy demonstrated 1 anatomical reduction, 2 imperfect reductions, and 1 poor reduction. The final attending radiologist report did not comment on any patient with cortical impaction. CONCLUSIONS: Our study demonstrates that a small number of patients sustain cortical impaction of the posterosuperior acetabular cortical surface along with their posterior wall acetabular fracture-dislocation. Although uncommon, preoperative imaging should be scrutinized to identify this clinical entity. As part of the preoperative plan, the surgeon can anticipate the cortex available for reduction verification and whether any additional steps or altered surgical approaches are needed to achieve an anatomical reduction. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Are piriformis reconstruction implants ideal for prophylactic femoral neck fixation?

OBJECTIVES: Prophylactic femoral neck fixation may be performed in the setting of geriatric diaphyseal femur fracture, pathologic or impending atypical femur fractures. Fixation constructs often utilize cephalomedullary implants with one or two proximal interlocking screws into the femoral head/neck. Variations in proximal femoral anatomy and implant design can interfere with the placement of two screws in the femoral head and neck. Our objective was to assess the strength of piriformis entry reconstruction implants with one versus two proximal interlock screws for prophylactic femoral neck fixation. METHODS: Thirty fourth generation synthetic femur models were separated into 5 groups. The control group was an intact femur, and the second group was an intact femur with an entry hole in the piriformis fossa. The remaining groups had an intramedullary nail placed with either 0, 1, or 2 screws placed into the femoral head and neck. Each femur was mechanically loaded along the mechanical axis through the femoral head. Load to failure and failure displacement were recorded. RESULTS: Mean load to failure was 5583 ± 543 N in the intact femur. Constructs with 2 screws had a significantly higher mean load to failure (3223 ± 474 N) compared to one screw constructs (2368 ± 280 N). All of the experimental groups remained significantly lower than the intact femur model (p < 0.05). CONCLUSION: Our results demonstrate that piriformis entry reconstruction implants have a significantly lower load to failure compared to an intact femur irrespective of screw construct. Further studies are needed to investigate this potential iatrogenic weakening.