Thomas A. Russell

Avoidance of Malreduction of Proximal Femoral Shaft Fractures With the Use of a Minimally Invasive Nail Insertion Technique (minit)

Objectives: To determine our rate of malalignment in proximal femoral shaft fractures treated with intramedullary (IM) nails, with and without the use of a minimally invasive nail insertion technique (MINIT). Design: Retrospective study. Setting: Level 1 trauma center. Methods: Between July 1, 2003, and June 31, 2005, 100 consecutive proximal femoral shaft fractures (97 patients) were treated with IM nails. The average age of the 56 men and 41 women was 43.5 years (range, 17 to 96 years). There were 92 closed fractures and 8 open fractures. Fractures were classified according to the Russell-Taylor classification (69 type 1A, 11 type 1B, 3 type 2A, 17 type 2B). All patients underwent antegrade IM nailing using a fracture table in the supine (83) or lateral (17) position. A total of 72 entry portals were trochanteric, and 28 were piriformis. Seventy-seven percent of the femurs were opened with MINIT, a technique that uses a percutaneous cannulated channel reamer over a guide pin as opposed to the standard method of Kuntscher, which employs a femoral awl. Nails were locked proximally using standard locking in 37 fractures, and recon mode in 63. Fracture reduction was examined on immediate postoperative films to determine angulation in the coronal and sagittal planes. Criteria for acceptable reduction were less than 5 degrees angulation in any plane. In addition, surgical position, entry portal, mechanism of injury, Russell-Taylor classification, OTA classification, open or closed fracture, open or closed reduction, and type of implant used were analyzed for significance. Results: The frequency of malalignment was 10% for the entire group of patients. Malalignment occurred in 26% of fractures treated without the use of the MINIT and in 5.2% when the MINIT was used (P < 0.01). There was no statistically significant difference between the different Russell-Taylor fracture types, although there was a trend towards more malalignment in type 2A and 2B fractures (P = 0.06). None of the other factors studied had a statistically significant effect on malalignment. A whole-model test of the factors that were surgeon-controlled (use of the MINIT, surgical position, open or closed reduction, type of implant used, and entry portal) found that only use of the MINIT had a statistically significant effect on malalignment (P < 0.01). Conclusions: The results indicate that use of the minimally invasive nail insertion technique (MINIT) significantly decreases the occurrence of malalignment in proximal femoral shaft fractures.

A comparison of optical and electromagnetic computer-assisted navigation systems for fluoroscopic targeting.

Objectives: Freehand targeting using fluoroscopic guidance is routine for placement of interlocking screws associated with intramedullary nailing and for insertion of screws for reconstruction of pelvic and acetabular injuries. New technologies that use fluoroscopy with the assistance of computer guidance have the potential to improve accuracy and reduce radiation exposure to patient and surgeon. We sought to compare 2 fluoroscopic navigation tracking technologies, optical and electromagnetic versus standard freehand fluoroscopic targeting in a standardized model. Intervention: Three experienced orthopaedic trauma surgeons placed 3.2-mm guide pins through test foam blocks that simulate cancellous bone. The entry site for each pin was within a circular (18-mm) entry zone. On the opposite surface of the test block (130-mm across), the target was a 1-mm-diameter radioopaque spherical ball marker. Each surgeon placed 10 pins using freehand targeting (control group) navigation using Medtronic iON StealthStation (Optical A), navigation using BrainLAB VectorVision (Optical B), or navigation using GE Medical Systems InstaTrak 3500 system (EM). Outcome Measurements: Data were collected for accuracy (the distance from the exit site of the guidewire to the target spherical ball marker), fluoroscopy time (seconds), and total number of individual fluoroscopy images taken. Results: The 2 optical systems and the electromagnetic system provided significantly improved accuracy compared to freehand technique. The average distance from the target was significantly (3.5 times) greater for controls (7.1 mm) than for each of the navigated systems (Optical A = 2.1 mm, Optical B = 1.9 mm EM = 2.4 mm; P < .05). Accuracy was similar for the 3 navigated systems, (P > 0.05). The ability to place guidewires in a 5-mm safe zone surrounding the target sphere was also significantly improved with the optical systems and the EM system (99% of wires in the safe zone) compared to controls (47% in the safe zone) (P < 0.002). Safe zone placement was similar among the 3 navigated systems (P > 0.05). Fluoroscopy time (seconds) and number of fluoroscopy images were similar among the three navigated groups (P > 0.05). Each of these parameters was significantly less when using the computer-guided systems than for freehand-unguided insertion (P < 0.01). Conclusions: Both optical and electromagnetic computer-assisted guidance systems have the potential to improve accuracy and reduce radiation use for freehand fluoroscopic targeting in orthopaedic surgery.

The Problem of Fracture Fixation Augmentation and Description of a Novel Technique and Implant for Femoral Neck Stabilization

Fracture augmentation for osteopenic bone is a widely accepted concept but not commonly used due to the difficulty with application of the materials in conjunction with surgical implants in fracture repair. Until recently there was little choice of materials for augmentation, but new formulations of structural orthobiological matrix (SOM) have been developed, which have better flow and setting properties than the original polymethylmethacrylate and calcium phosphate ceramics materials. In addition, a new class of injectable implants with the ability to deliver some of these newer SOMs has been designed and received regulatory clearance as fracture fixation devices. This cadaveric study was undertaken to assess the feasibility of using the N-Force Fixation System in a femoral neck fracture model with 6 different SOMs. A new property of SOM was discovered regarding the flow characteristics of the tested materials within the proximal femur. Intrusion and extrusion characteristics were observed and were SOM specific. C-arm fluoroscopy and CT studies revealed the ability of intrusion-type SOM to intrude into cancellous bone trabeculae and minimize the chance of joint extrusion through fracture lines, whereas extrusion-type SOM would not intrude into trabecular spaces and demonstrated a tendency for fracture site extrusion and fracture contact interposition, risking compromise of fracture healing and angiogenesis. The instrumentation and implants gave reproducible implant placement and SOM delivery with low-pressure application and circumferential augmentation from the near cortex extending into the femoral neck and head in a tapering cone-type pattern.

Hot Topics in Biomechanics: Hip Fracture Fixation.

Summary: Geriatric hip fractures continue to increase in frequency as the population ages, and intertrochanteric femur fractures are a significant part of these injuries. Plate fixation for intertrochanteric fractures of the proximal femur has been in use for many years, and application of the sliding hip screw has also been a mainstay of treatment. Recent data suggest there may be a benefit to using implants that add rotational stability to the proximal intertrochanteric fragment. Although preliminary data are promising, there is need for improved investigation to demonstrate the benefit of these new implant designs. In this era of increasing emphasis on cost, quality, and value, better data are needed to help clinicians determine the best therapy for their patients.

Hip Fractures: Surgical Tactics and New Concepts

Fractures of the hip are the most common surgically treated injuries of the long bones and yet are the most controversial due to their combination of high 1-year mortality and equally high disability after surgical treatment. These injuries require extensive medical resource utilization with the attendant societal and health care cost burden. This issue of Techniques in Orthopaedics is designed to provide current methods to improve the reduction and stabilization of these difficult fractures and to explore previously unrecognized problems and potential solutions. This review is presented in two parts with biomechanics and femoral neck fracture focus for the March issue, and pertrochanteric and subtrochanteric fractures in the following issue. Fractures about the hip are divided somewhat arbitrarily into fractures of the femoral neck, pertrochanteric region, and subtrochanteric region. There is frequent overlap of these regions. There is general agreement as to the idealized fracture patterns for each region (Table 1). However, there are no scientifically validated classification systems that can demonstrate reproducibility from one surgeon to another. Additionally problematic is the realization that these classifications systems are frequently determined by 2-dimensional radiographs, which may underestimate the extent of the injury and compromise the chosen surgical construct with resultant instability and fracture collapse. Biomechanical analysis of hip fracture models has been a key component of understanding failure mechanisms of surgery. This symposium provides an update of the current biomechanical models and potential new models. Reduction has universally been regarded as the key component in successful surgical treatment of internal fixation in hip fractures. This symposium gathers experience from accomplished surgeons specializing in hip fractures in Europe and North America. The techniques of obtaining reduction and maintaining the reduction are based on years of experience and extraordinary case volumes in the author’s respective series. Both plate and nail advocates explain their results and techniques for optimal usage of their respective systems. In a previous issue of Techniques in Orthopaedics, the author introduced a new classification for hip fracture implant options that was designed to give insight into the advantages and potential failure modes for the 4 main classes of plate and nail constructs. They made use of surgical mechanisms to enhance stability of the fracture implant construct and consisted of: (1) Impaction; (2) Compression with single head components; (3) Compression with double screw head components; and (4) Linear compression with at least 2 head components. This classification system requires amendment because of the addition of a new class of implants, which are differentiated by the ability to provide augmentation to the metallic fixation at the trabecular bone-implant interface. These augmentation components integrate with the previous generation of devices such that the exposure and reduction techniques remain universal. The addition of the augmentation material is applied after completion of the reduction and definitive metallic fixation. The orthobiological materials used with the implants are primarily calcium phosphate ceramics with non-newtonian fluidic behavior. Currently, few materials have been cleared by the governmental regulatory agencies, but more can be expected. The scientific literature has been veiled as to the complications of hip fractures with regard to deformity and its effect on functional recovery. Newer studies of femoral neck shortening are increasing our understanding of the unrecognized complications with traditional surgery. I want to thank all of the authors of this symposium for their selfless contribution to this journal and to the patients we treat.

Use of blocking screws in intramedullary nailing of long-bone fractures

Metaphyseal and metadiaphyseal long-bone fractures often can be treated with intramedullary nails; however, these fracture types are considered higher risk for late displacement and malunion. Blocking screws provide a percutaneous technique to improve alignment and strengthen fixation constructs in these challenging fracture patterns. Both translation and angular deformity can be corrected with appropriately placed blocking screws, and acceptable clinical outcomes have been demonstrated in the literature.