Anterior Cortical Perforation Research Articles

Influence of greater trochanteric starting point on distal anterior cortical perforation during antegrade femoral nailing

Background: Distal anterior cortical perforation is 1 complication of antegrade femoral nailing. The effect of greater trochanteric (GT) starting points on cortical perforation risk has not been described in human femoral models. This study assessed the influence of sagittal plane starting point on rate of anterior cortical perforation using 3D CT-reconstructions of human femora. Secondarily, patient age and nail radius of curvature (ROC) were assessed as risk factors. Methods: CT scans of 53 patients (18 non-geriatric (<65 yr), 35 geriatric (>65 yr)) with non-fractured femora were converted into dynamic 3D-reconstructed renderings. Medullary nails from two manufacturers that differed in ROC were digitally templated in each femur from an anterior, central, and posterior ⅓ GT starting point. The rate of anterior cortical perforation and distance from the inner anterior cortex to the nail tip were recorded. Results: Perforation rate increased significantly as starting point moved from anterior (6%), to central (43%), to posterior (79%) regardless of patient age or implant manufacturer (P<0.001). On average, an anterior starting point positioned the nail tip furthest from the inner anterior cortex (5. mm), safely within the canal (P<0.001). Perforation rate was significantly increased in the geriatric versus non-geriatric population (47% vs. 34%) (P=0.028), and when using the nail with the larger versus smaller ROC (50% vs. 36%) (P=0.03). Conclusion: Distal nail sagittal alignment is sensitive to both patient and treatment factors. A posterior starting point, increased age (>65 yr), and increased implant ROC significantly increase risk for anterior cortical perforation of the distal femur. Level of Evidence: III

Biomechanical Consequences of Nail Insertion Point and Anterior Cortical Perforation for Antegrade Femoral Nailing.

This biomechanical study assessed the influence of changing antegrade cephalomedullary nail insertion point from anterior to neutral to posterior locations relative to the tip of the greater trochanter with or without anterior cortical perforation in the distal femur. Artificial osteoporotic femurs and cephalomedullary nails were used to create 5 test groups each with 8 specimens: intact femur without a nail or perforation, anterior nail insertion point without perforation, neutral nail insertion point without perforation, posterior nail insertion point without perforation, and posterior nail insertion point with perforation. Nondestructive biomechanical tests were done at 250 N in axial, coronal 3-point bending, sagittal 3-point bending, and torsional loading in order to measure overall stiffness and bone stress. The intact femur group vs. all femur/nail groups had lower stiffness in all loading modes (p ≤ 0.018), as well as higher bone stress in the proximal femur (p ≤ 0.027) but not in the distal femur above the perforation (p = 0.096). Compared to each other, femur/nail groups only showed differences in sagittal 3-point bending stiffness for anterior and neutral vs. posterior nail insertion points without (p ≤ 0.025) and with perforation (p ≤ 0.047). Although it did not achieve statistical significance (p ≥ 0.096), moving the nail insertion point from anterior to neutral to posterior to posterior with perforation did gradually increase bone stress by 45% (proximal femur) and 46% (distal femur). No femur or hardware failures occurred. Moving the nail insertion point and the presence of a perforation had little effect on stiffness, but the increased bone stress may be important as a predictor of fracture. Based on current bone stress results, surgeons should use anterior or neutral nail insertion points to reduce the risk of anterior cortical perforation.

The Feasibility of Assessing the Cortical Bone Trajectory Screw Placement Accuracy Using a Traditional Pedicle Screw Insertion Evaluation System.

This was a retrospective observational study. We aimed to characterize the feasibility of assessing the accuracy of cortical bone trajectory (CBT) screw placement in midline lumbar interbody fusion using a traditional pedicle screw insertion accuracy evaluation system based on computed tomography (CT). Since Santoni and colleagues proposed CBT as an alternative approach for the treatment of lumbar degenerative disease, CBT has been biomechanically and clinically investigated in detail. The reported misplacement rate was 0%-12.5%. Therefore, these cortical screws may result in severe complications, such as nerve root, vascular, and spinal cord injuries. However, to the best of our knowledge, the accuracy of the current assessment system of cortical bone screw placement has not been described clearly. Overall, 342 cortical screws of 69 consecutive patients with lumbar degenerative disease who underwent midline lumbar interbody fusion surgery in one surgeon's initial phase were examined retrospectively. A comprehensive and detailed pedicle screw accuracy classification and grading system was introduced in our study, including 5 types of misplacement: (1) medial and (2) lateral cortical bone perforation (MCP and LCP) of the corresponding pedicle, (3) anterior cortical bone perforation of the vertebral body, (4) endplate perforation, and (5) foraminal perforation (FP). The degree of interobserver and intraobserver agreement with regard to the screw positions based on CT were used as indicators of the reliability of the modified classification system. All patients were retrospectively assessed for screw placement-related complications throughout the entire treatment course to evaluate the relationship between the procedure adequacy and neurological symptoms. The interobserver and intraobserver agreements were substantial-to-almost perfect (κ=0.78 and 0.88, respectively) in distinguishing the acceptable-placed pedicle screws from those with partial or complete cortical perforation. In the MCP and LCP-the most common types of misplacement-the interobserver agreement was substantial (κ=0.70 and 0.76, respectively), and the intraobserver agreement was almost perfect (κ=0.85 and 0.89, respectively). In total, there are 7 (2.05%) MCP and 65 (19.01%) LCP screws. The screw placement-related complication rate is significantly higher in the MCP and FP groups than that in the LCP group. Our study demonstrated that using a pedicle screw classification and grading system based on CT to assess the accuracy of CBT screw placement is feasible and practical. MCP and FP screws are more likely to cause neurological deficits with statistical significance, especially grade 2 MCP. We recommend inexperienced surgeons choose a lateral trajectory rather than a medial one if they cannot ensure accurate screw insertion. Level III.

Early Experience with the Trochanteric Fixation Nail-Advanced (TFN-A): A Descriptive Review of Thirty-Four Cases from a Single Center.

The Trochanteric Fixation Nail-Advanced (TFN-A) is offered as a "next-generation" solution to the ever-increasing incidence of pertrochanteric and intertrochanteric fractures. It aims to build upon the success of earlier-generation proximal femur implants, while at the same time attempting to address complications, like varus collapse, cut-out, implant failure and anterior cortical perforation/impingement. It also aims to provide the surgeon with flexibility by offering varied options under a single implant system. This descriptive study looked at the early outcomes of the TFN-A as used in a single trauma centre. It attempts to shed light on the question of whether the TFN-A is at least equivalent to more established proximal femur implants in terms of fixation while reducing complication rates. Thirty-four patients who underwent fixation using the TFN-A at a single centre from October 2016 to July 2018 were retrospectively reviewed for this study. All surgeries were done by experienced orthopaedic surgeons. The decision for cement augmentation of the femoral head element was made on a case-to-case basis. Radiographs of the hip, pelvis and femora were taken to monitor fracture healing and evaluate post-fixation neck-shaft angle (NSA)/varus collapse, cut-out/cut-through, implant failure and anterior cortical impingement/perforation. All thirty-four patients had neck-shaft angles within 5 degrees of the contralateral hip immediately post-surgery. Two patients had varus collapse > 5 degrees on follow-up but did not progress to cut-out. Two patients had broken distal locking screws, albeit their fractures healed uneventfully. There were four cases of cement augmentation with "retrograde filling", wherein most of the cement went into the femoral neck. No patients experienced distal anterior cortical impingement or perforation. All but one patient subsequently progressed to full weight-bearing. Early experience with the TFN-A appears to suggest that it is at least comparable to preceding proximal femur nail devices in terms of fixation. Absence of anterior cortical impingement or perforation suggests that the TFN-A shows promise in addressing this issue. The incidence of "retrograde cement filling" is a previously unreported point of interest for head-neck element augmentation which requires further study.

Reverse total shoulder arthroplasty using helical blade to optimize glenoid fixation and bone preservation: preliminary results in thirty five patients with minimum twoyear follow-up.

Glenoid loosening is a common cause of reverse total shoulder arthroplasty (RTSA) failure, and grafting of the glenoid is often required for revision due to bone loss due to the central peg in most glenoid baseplates. Helical blades have been used in the hip to optimize bone fixation in proximal femoral fracture. This study presents the initial results of specifically designed helical blade in the shoulder to optimize glenoid bone fixation and preservation as part of RTSA. Thirty-five patients underwent RTSA with glenoid helical blade fixation. An uncemented glenoid baseplate was used with a central helical blade partially coated with hydroxyapatite and two or three screws. Outcome analysis was performed pre-operatively and at twoyears. All patients were satisfied with the results and significant improvement was observed in functional outcome scores between baseline and final follow-up. There was a single intra-operative undisplaced glenoid fracture which did not compromise the baseplate fixation. There was no radiographic evidence of loosening or radiolucencies around the helical blade. The helical blade provides a satisfactory primary fixation. Because of its length (21mm), care should be taken in cases of pre-existing bone loss or sclerotic bone to avoid glenoid fracture or anterior cortical perforation. Helical blade has the potential to facilitate glenoid implant revision by preserving the glenoid bone stock.

Mismatch of long Gamma intramedullary nail with bow of the femur: Does radius of curvature of the nail increase risk of distal femoral complications?

IntroductionAnterior cortical penetration of the distal nail tip is a recognized complication of intra-medullary nailing of the femur particularly in the geriatric population. This has been attributed to a mismatch between the femoral bow and the radius of curvature (ROC) of the femoral nail. We wanted to see if there was a reduction of this risk comparing cephalomedullary nails with ROC of 200 cm and 150 cm. Methods52 patients were split into 2 groups similar with respect to age, sex and comorbidities. Group A with 25 patients used a nail with a ROC of 200 cm and Group B with 27 patients used a 150 cm ROC nail. Lateral radiographs of the distal femur were evaluated to note the position of the nail tip in relation to the femoral canal. The diameter of the femur at the tip of the nail was divided into 3 equal zones. The anterior one-third was designated as Zone1, the middle one-third as Zone 2 and the posterior one-third as Zone 3. Results80% of the cases with a 200 cm ROC nail had the tip of the nail in the anterior one-third of the canal (zone 1). Fracture of the anterior femoral cortex distally by the nail tip was seen in 2 patients.Only 18.5% of cases with a 150 cm ROC nail had the tip of the nail in anterior one-third of the canal (zone 1). There were no incidences of complications such as fractures and anterior cortical perforation. ConclusionsA cephalomedullary nail with a ROC of 150 cm had its distal tip more towards the center of the femoral canal when compared to a nail with ROC of 200 cm. No case of anterior femoral penetration was seen when using a nail with an ROC of 150 cm.

Anthropometric Computed Tomography Reconstruction Identifies Risk Factors for Cortical Perforation in Revision Total Hip Arthroplasty

BackgroundThe incidence of revision hip arthroplasty is increasing with nearly 100,000 annual procedures expected in the near future. Many surgeons use straight modular tapered stems in revisions; however, complications of periprosthetic fracture and cortical perforation occur, resulting in poor outcomes. Our objective was to identify patient demographics and femoral characteristics that predispose patients to cortical perforation when using the straight modular stems. MethodsWe used a computed tomography database and modeling software to identify patient demographics and morphologic femoral characteristics that predispose patients to cortical perforation during revision hip arthroplasty. Overall, 561 femurs from patients of various backgrounds were used, and statistical analysis was performed via the 2-sample t test. ResultsDecreased patient height (mean 163.0 vs 168.8 cm), radius of curvature (818 vs 939 mm), anterior–posterior (8.5 vs 13.8 mm) and medial–lateral (7.9 vs 11.3 mm) width of the isthmus, and distance of the isthmus from the greater trochanter (179 vs 186 mm) were all statistically significant risk factors for cortical perforation (P < .05). ConclusionThis study identifies several patient-specific risk factors for cortical perforation during revision hip arthroplasty using straight modular tapered stems and highlights the importance of preoperative planning especially in patients with shorter stature, proximal location of the femoral isthmus, narrow femoral canal, and smaller radius of curvature. Also, when using a mid-length modular tapered stem without an extended trochanteric osteotomy, consideration should be given to using a kinked stem to avoid anterior cortical perforation.

Pedicle violation and Navigational errors in pedicle screw insertion using the intraoperative O-arm: A preliminary report

BackgroundUse of computer-assisted insertion of pedicle screws has some advantages owing to the reportedly decreased incidence of pedicle breach and clinical events. Registration-based methods based on preoperative computed tomography imaging, 2D fluoroscopy, and 3D fluoroscopy are the most popular, however each has its limitations. O-arm–based navigation, which uses intraoperative acquisition and registration of navigated images, may overcome many of these disadvantages. We set out to study the clinical accuracy and navigational accuracy for pedicle screw insertion using our recently acquired O-arm and present our preliminary findings. MethodsThe first 26 patients operated consecutively for L4-5 fusion were included in the study. O-arm–based navigation was used to insert the pedicle screws. Postoperative computed tomography images were acquired and assessed for pedicle breach and anterior cortical perforation. Planned trajectories of each screw were compared with the actual trajectories in the postoperative images to assess navigational accuracy in both axial and sagittal planes. ResultsA total of 104 screws were inserted. One screw (1%) breached the pedicle laterally. Nonsignificant anterolateral cortical perforations were noted in 7 screws (6.7%), all of which occurred at L5 level. The mean axial and sagittal navigational error was 2.3° (± 1.7) and 3.1° (± 2.3), respectively. There were no significant differences in the errors between L4 or L5 level. The occurrence of anterior perforation correlated with the degree of axial (P = .02) but not sagittal (P = .12) navigational error. There were no clinical events related to the screw insertion. ConclusionUse of O-arm–guided pedicle screw insertion was associated with low incidence of pedicle breach (1%) and a low range of navigational error in both sagittal and axial planes. Anterolateral vertebral body perforation was higher at L5 without any negative clinical events. Despite the high need for technical support, we found that O-arm was a very efficient tool for accurate pedicle screw insertion.

Does Modern Nail Geometry Affect Positioning in the Distal Femur of Elderly Patients With Hip Fractures? A Comparison of Otherwise Identical Intramedullary Nails With a 200 Versus 150 cm Radius of Curvature

To compare implant positioning in the distal femur between 2 cohorts of elderly patients treated for a hip fracture with a long 200- or 150-cm radius of curvature (ROC) cephalomedullary nail. We theorized that the 150-cm ROC nails would more closely approximate the femoral bow and result in fewer implant-related complications. Retrospective Comparative Study. Single Level II Trauma Center. Fifty-eight geriatric patients with a hip fracture (26 in 200-cm nail cohort and 32 in 150-cm nail cohort). Long cephalomedullary nailing using single hip fracture nail and instrumentation system (InterTAN) before and after transition from a 200- to 150-cm ROC long hip nail. Anteroposterior position of distal nail tip on intraoperative lateral radiograph (where 0.50 indicates midaxial, perfectly central placement) and implant-related complications (anterior cortical abutment, perforation, or fracture). The average position of nails with a 150-cm ROC was closer to the midaxial line of the distal femur compared with 200-cm nails (0.63 vs. 0.55, P = 0.02). Only 1 of 26 (3.8%) 200-cm ROC nails was placed at the midaxial line and none were posterior, whereas 9 of 32 (28%) 150-cm ROC nails were positioned at or posterior to this line (P = 0.006). Only 1 nail with a 150-cm ROC abutted the distal femur's anterior cortex compared with 3 in the 200-cm cohort-including one that caused a fracture. Femoral nails with a 150-cm ROC more closely approximate the femoral bow of geriatric hip fracture patients than 200-cm ROC nails, appearing less likely to cause complications such as anterior cortical abutment, perforation, or fracture. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cortical Encroachment After Cephalomedullary Nailing of the Proximal Femur

: A unique complication of using full-length intramedullary nails for pertrochanteric and subtrochanteric femur fractures is nail penetration of the anterior cortex at the distal end of the femur because of a mismatch of the anatomic femoral bow with that of currently available cephalomedullary nails (CMNs). This study was performed to determine the rate of distal femoral cortical penetration after stabilization of the proximal femur in a consecutive series of patients using a long CMN with a curvature of 180 cm and to examine the final location of the nails within the femoral canal. : Retrospective chart review. : Level 1 trauma center with tertiary care. : Between June 2005 and September 2008, 271 consecutive proximal femoral fractures or impending fractures were stabilized using a specially designed CMN [pertrochanteric nail (PTN) system; Biomet, Warsaw, IN]. Fifty-seven fractures were excluded because of inadequate lateral radiographs, leaving 214 nails in 212 patients available for analysis. : The proximal femur fractures or impending fractures were stabilized with a full-length CMN with a shaft diameter of 11 mm and a radius of curvature of 180 cm. : Nail position was determined from the lateral radiograph, which included the minimal distance from the nail to the anterior cortex of the distal femur and the relative position of the nail within the medullary canal, at a level within 2 cm proximal to the superior pole of the patella. Based on the nail position within the distal femoral canal, the following were calculated: (1) the overall rate of distal femoral anterior cortical penetration, (2) the distribution of nail distances to the anterior cortex, and (3) the proportion of nails lying in each quarter of the space available for the nail. : Four surgeries (1.9%) were performed for pathologic fracture and 22 (10.3%) for impending pathologic fracture. The remaining 188 CMNs were used to stabilize OTA Type 31A1 fractures (52 nails, 24.3%), Type 31A2 fractures (62 nails, 29%), Type 31A3 fractures (15 nails, 6.5%), and Type 32 fractures (59 nails, 27.6%). Of the 214 cases available for radiographic analysis, there was 1 case (0.47%) of distal femoral anterior cortical penetration. Of the remaining 213 CMNs, 40% of nails ended up far anterior, 48% anterior, 10% posterior, and 2% far posterior. Sixteen percent (1/6) were within 3 mm of the anterior cortex and half were within 7 mm. The average distance from nail to the anterior cortex was 8.5 mm. : Use of a CMN with a radius of curvature of 180 cm to stabilize the proximal femur resulted in a very low rate of distal femoral anterior cortical penetration. However, most of the intramedullary nails ended up in the anterior half of the space available for the nail with 16% within 3 mm of the anterior cortex. These results highlight the importance of being aware of the complication of anterior cortical impingement and perforation during CMN insertion. : Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Different Proximal Thoracic Curve Patterns Have Different Relative Positions of Esophagus to Spine in Adolescent Idiopathic Scoliosis

A computed tomography (CT) study. To evaluate the changed relative positions of esophagus in proximal thoracic (PT) curves of adolescent idiopathic scoliosis (AIS) patients and analyze the potential risks of esophageal injuries from thoracic pedicle screw (TPS) insertion. Translation and rotation of the vertebrae could lead to altered relative positions of surrounding vital structures in AIS patients. The changed positions of aorta and spinal cord in main thoracic (MT) curve have been comprehensively investigated; however, no studies have analyzed the relative position of esophagus in PT curve. Twenty patients with complete proximal thoracic (CPT group) curve, 22 patients with fractional proximal thoracic (FPT group) curve, and 14 normal patients with a straight spine (normal group) were included. Axial CT images from T2 to T5 at the midvertebral body level were obtained to evaluate esophagus-vertebral angle (EVA, defined as 0° when the esophagus was located directly lateral to the left, 90° when strictly anterior, and 180° when directly lateral to the right). The percentages of esophagus in the direction of screw passage were calculated to analyze potential risks of esophageal injuries during TPS insertion. EVA in the FPT group was significantly smaller than that in the normal group (P < 0.05), whereas EVA in the CPT group was significantly greater than that in the normal group (P < 0.05) at each level. The esophagus was located approximately anterior to the vertebral body in the normal group but shifted anterolaterally to the right in the CPT group and anterolaterally to the left in the FPT group. The esophagus was at a high risk of injury with right anterior penetrated TPS in the CPT group and was at a high risk of injury with left anterior penetrated TPS in the FPT group. Different anatomic patterns of PT curves could cause different altered positions of esophagus relative to spine and result in different potential risks of esophageal injuries during TPS insertion. Spine surgeons should choose appropriate pedicle screw length to avoid anterior cortical perforation in the PT region of AIS patients.

The rate of screw misplacement in segmental pedicle screw fixation in adolescent idiopathic scoliosis

Background and purpose There are no reports in the literature on the influence of learning on the pedicle screw insertion. We studied the effect of learning on the rate of screw misplacement in patients with adolescent idiopathic scoliosis treated with segmental pedicle screw fixation.Method We retrospectively evaluated low-dose spine computed tomography of 116 consecutive patients (aged 16 (12–24) years, 94 females) who were operated during 4 periods over 2005–2009 (group 1: patients operated autumn 2005–2006; group 2: 2007; group 3: 2008; and group 4: 2009). 5 types of misplacement were recorded: medial cortical perforation, lateral cortical perforation, anterior cortical perforation of the vertebral body, endplate perforation, and perforation of the neural foramen.Reslts 2,201 pedicle screws were evaluated, with an average of 19 screws per patient. The rate of screw misplacement for the whole study was 14%. The rate of lateral and medial cortical perforation was 7% and 5%. There was an inverse correlation between the occurrence of misplacement and the patient number, i.e. the date of operation (r = –0.35; p < 0.001). The skillfulness of screw insertion improved with reduction of the rate of screw misplacement from 20% in 2005–2006 to 11% in 2009, with a breakpoint at the end of the first study period (34 patients).Interpretation We found a substantial learning curve; cumulative experience may have contributed to continued reduction of misplacement rate.

Safe zone for anterior cortical perforation of the ulna during tension-band wire fixation: A magnetic resonance imaging analysis

Placing K-wires obliquely through the anterior ulnar cortex is a common modification of traditional olecranon tension-band wiring. Wire tip protrusion, however, risks injury to adjacent neurovascular structures and may impede forearm rotation. This study examines the proximity of neurovascular structures to the anterior proximal ulnar cortex. The anatomy of 47 adult elbows was examined through magnetic resonance imaging. A radiologist measured the spatial relationship of 6 neurovascular structures to a mid-sagittal reference point 1.5 cm distal to the coronoid on the anterior surface of the ulna. Distance and angular measurements were made in the transverse plane of the reference point. Within a reasonable arc of K-wire placement, the ulnar artery and median nerve were at greatest risk yet were still beyond 10 mm from the anterior ulnar cortex. To avoid iatrogenic neurovascular injury during tension-band wiring of the olecranon, protrusion of wire tips beyond the anterior ulnar cortex should be no more than 1 cm at a distance of 1.5 cm distal to the coronoid.