The effect of two different trochanteric nail lag-screw designs on fixation stability of four-part intertrochanteric fractures: a clinical and biomechanical study.

OBJECTIVES: To compare lag-screw sliding characteristics and fixation stability of two cephalomedullary nails (CMN) with different lag-screw designs (solid and telescopic), we conducted a biomechanical study and an analysis of clinical results. METHODS: Six pairs of cadaver femurs with simulated intertrochanteric fractures were randomly assigned to one of two CMN fixations. Femur constructs were statically then cyclically loaded on an MTS machine. Lag-screw sliding and inferior and lateral femoral head displacements were measured, following which failure strength of the construct was determined. Forty-five patients with intertrochanteric fractures treated with these CMN were identified. Medical records and radiographs were reviewed and analyzed using Fisher's exact test and Student's t test to determine lag-screw sliding. RESULTS: No difference was seen with cycling in inferior femoral head displacement between the two screw designs. The solid screw had an average inferior head displacement of 1.75 mm compared with 1.59 mm for the telescoping screw (p = 0.772). The solid lag screws slid an average of 2.79 mm lateral from the nail, whereas the telescoping screws slid an average of 0.27 mm (p = 0.003). In our clinical review, the average lateral sliding of the telescoping screw was 0.5 mm and of the solid screw was 3.7 mm (p < 0.001). Despite differences in lateral sliding, there were no reoperations for prominent or painful hardware in either group. CONCLUSIONS: Both designs are acceptable devices for stabilization of intertrochanteric fractures. Clinical and biomechanical data demonstrate greater lateral sliding in the solid lag-screw group, making for greater potential for lateral-sided hip pain in CMNs with solid lag screws as opposed to telescoping lag screws.

Midfoot fusion: a biomechanical comparison of plantar planting vs intramedullary screws.

BACKGROUND: Numerous reconstructive techniques for midfoot collapse secondary to Charcot neuroarthropathy have been described, but few have been studied biomechanically. The purpose of this study was to biomechanically compare 2 of the most common techniques. METHODS: Seven paired below-knee specimens were amputated through the talonavicular and calcaneocuboid joints. The nonligamentous soft tissue was stripped proximal to the metatarsal heads and disarticulated through the tarsometatarsal (TMT) joints. For each paired specimen, the TMT joints were fused by plantar plating or intramedullary screw fixation for the contralateral side. The specimens were mounted, loaded, and cycled, and fixation stiffness was determined. Load versus displacement graphs were used to calculate overall construct stiffness, and data were analyzed by Student t tests. RESULTS: There was no failure of hardware. All failures were at the bone-implant interface. Failure was either by screw pull-out, bone fracture, or a combination of the two. There were no notable differences between the 2 fixation techniques with respect to stiffness or loads to failure. There was a trend toward a stiffer first TMT construct using the plantar plating method. Five of the 7 screw fixations failed by pullout of the base of the first metatarsal and the other 2 by pullout of screws from all MT bases. Seven of the 7 plantar plate fixations failed by separation of the fifth to third MT bases originating at the fifth, and 3 showed fracture of the fifth metatarsal base. CONCLUSIONS: There was no notable biomechanical difference between the 2 techniques. There was a trend toward a stiffer construct at the first TMT with plantar plating. CLINICAL RELEVANCE: This study biomechanically analyzes two common Charcot midfoot reconstruction techniques and highlights the need for further study of both techniques and combinations of these techniques.

Who is lost to followup?: a study of patients with distal radius fractures.

Distal radius fractures are the most common upper extremity fracture, representing one-sixth of all fractures treated in emergency departments nationwide. Beyond the initial reduction and immobilization of these fractures, providing proper followup to ensure maintenance of the reduction and identify complications is necessary for optimal recovery of forearm and wrist functions. We sought to identify the clinical and demographic factors that characterize patients with distal radius fractures who do not return for followup and to assess the underlying causes for their poor followup rates. Compared with patients who were compliant with followup, those lost to followup had lower Physical and Mental Health scores on the SF-36 forms, more often were treated nonoperatively, and more likely had not surpassed secondary education. However, we found no difference between these two groups based on age, gender, mechanism of injury, marital status, or hand dominance. Early identification of patients who potentially are noncompliant can result in additional measures being taken to ensure the patient's return to the treating hospital and physicians. This in turn will prevent complications attributable to lack of followup and allow more accurate assessment of results, thereby improving patient outcomes.

Analysis of Postoperative Thoracolumbar Spine Infections in a Prospective Randomized Controlled Trial Using the Centers for Disease Control Surgical Site Infection Criteria.

INTRODUCTION: Wound infections following spinal surgery place a high toll on both the patient and the healthcare system. Although several large series studies have examined the incidence and distribution of spinal wound infection, the applicability of these studies varies greatly since nearly every study is either retrospective and/or lacks standard inclusion criteria for defining surgical site infection. To address this void, we present results from prospectively gathered thoracolumbar spine surgery data for which the Centers for Disease Control (CDC) criteria were stringently applied to define a surgical site infection (SSI). METHODS: A prospective randomized trial of 314 patients who underwent multilevel thoracolumbar spinal surgery with instrumentation followed by postoperative drain placement was completed (Takemoto et al., 2015). The trial consisted of two antibiotic arms: one for 24-hours, and the other for the duration of the drain; no differences were found between the arms. All infections meeting CDC criteria for SSI were included. RESULTS: A total of 40 infections met CDC criteria for SSI, for an overall incidence of 12.7%. Of these, 20 (50%) were culture-positive. The most common organism was Staphylococcus aureus (4 total: methicillin-sensitive=2; methicillin-resistant=2), followed by coagulase-negative Staphylococcus (3 cases), Propionibacterium acnes and Escherichia coli (2 cases each). Six infections grew multiple organisms, most commonly involving coagulase-negative staphylococcus and enterococcus. CONCLUSIONS: Our findings indicate that thoracolumbar SSI occurs at the higher end of the range cited in the literature (2-13%), which is largely based on retrospective data not subjected to the inclusivity of SSI as defined by the CDC. The three most common organisms in our analysis (S. aureus, P. acnes, E. coli) are consistent with previous reports. Staphylococcus aureus continues to be the most common causative organism and continued vigilance and searching for preventive measures need to be a high priority. This study provides Level I evidence.

Appropriateness of Twenty-four-Hour Antibiotic Prophylaxis After Spinal Surgery in Which a Drain Is Utilized: A Prospective Randomized Study.

BACKGROUND: Wound drains that are left in place for a prolonged period of time have a higher rate of bacterial contamination. Following spinal surgery, a drain is often left in place for a longer period of time if it maintains a high output. Given the major consequences of an infection following spinal surgery and the lack of data with regard to the use of antibiotics and drains, we performed a study of patients with a drain following spinal surgery to compare infection rates between those who were treated with antibiotics for twenty-four hours and those who received antibiotics for the duration for which the drain was in place. METHODS: We performed a prospective randomized trial of 314 patients who underwent multilevel thoracolumbar spinal surgery followed by use of a postoperative drain. The patients were randomized into two groups, one of which received perioperative antibiotics for twenty-four hours (twenty-four-hour group) and the other of which received antibiotics for the duration that the drain was in place (drain-duration group). Data collected included demographic characteristics, medical comorbidities, type of spinal surgery, and surgical site infection. RESULTS: Twenty-one (12.4%) of the 170 patients in the twenty-four-hour group and nineteen (13.2%) of the 144 in the drain-duration group developed a surgical site infection (p = 0.48). There were no significant differences between the twenty-four-hour and drain-duration groups with respect to demographic characteristics (except for the American Society of Anesthesiologists [ASA] classification), operative time, type of surgery, drain output, or length of hospital stay. CONCLUSIONS: Continuing perioperative administration of antibiotics for the entire duration that a drain is in place after spinal surgery did not decrease the rate of surgical site infections.

Evolution of atypical femur fractures and the association with bisphosphonates.

For almost 15 years bisphosphonates have been the mainstay of prevention and treatment of fragility fractures, particularly in post-menopausal women. As a result, there has been a decrease in fragility fractures, along with the health care costs associated with treating them. However, with all drugs, there are always concerns with side effects and potential complications. Atypical femur fractures have been observed in women taking bisphosphonates, a complication the drug was designed to prevent. There is no definitive link between bisphosphonates and atypical femur fractures and no proto- col to managing these fractures. This review discusses the evolution and development of bisphosphonates and offers the latest information regarding evidence surrounding the link to atypical femur fractures.

The effects of locked and unlocked neutralization plates on load bearing of fractures fixed with a lag screw.

OBJECTIVES: Because locked plates as a neutralization device for lag screw fracture fixation have different biomechanics than that of unlocked plates, we investigated how this would affect lag screw load at the fracture site. The purpose of this study was to assess the load at a fracture site compressed with a lag screw when both locked and unlocked plates are used as neutralization devices. MATERIALS AND METHODS: Nine cadaver femurs had a mid-shaft oblique fracture created and were fixed with a lag screw, incorporating load transducers at the fracture site and lag screw. Three neutralization plate constructs (a standard plate, a locked plate, and an offset locked plate) were sequentially applied and loaded. Loads at the fracture site and the lag screw were measured after sequential application of axial loads. RESULTS: Plate application to the lag screw fixations did not significantly change (P > 0.26) the load at the fracture site or on the lag screw that were approximately 200 N. The unlocked, locked, and offset locked plates behaved similarly. The addition of a load to the specimens did not change the lag screw loads but increased the average fracture loads by approximately 20% of the applied load. CONCLUSIONS: Unlocked and locked neutralization plates do not affect the initial compressive load across a fracture fixed by a lag screw, and both behave similarly in transferring the load when the fracture was loaded. For a well-fixed stable fracture fixed with a lag screw, there is no advantage in using a more expensive locked plate over a standard plate for neutralization purposes if adequate screw purchase can be achieved.

Treatment of two-part proximal humerus fractures: intramedullary nail compared to locked plating.

BACKGROUND: Two-part proximal humerus fractures are common orthopedic injuries for which surgical intervention is often indicated. Choosing a fixation device remains a topic of debate. PURPOSE: The purpose of this study is to compare two methods of fixation for two-part proximal humerus fractures, locking plate (LP) with screws versus intramedullary nailing (IMN), with respect to alignment, healing, patient outcomes, and complications. To our knowledge, a direct comparison of these two devices in treating two-part proximal humerus fractures has never before been studied. We hope that our results will help surgeons assess the utility of LP versus IMN. METHODS: A retrospective chart review was performed on 24 cases of displaced two-part surgical neck fractures of the humerus. Twelve shoulders were treated using IMN fixation and 12 others were fixated with LP. Data collected included sociodemographic, operative details, and postoperative care and function. RESULTS: Radiographic comparison of fixation demonstrated an average neck-shaft angle of 124° and 120° in the IMN group and LP group, respectively. Adjusted postoperative 6-month follow-up range of motion was 134° of forward elevation in the IMN group and 141 in the LP group. The differences in range of motion and in complication rates were not found to be significant. CONCLUSIONS: Our results suggest that either LP fixation or IMN fixation for a two-part proximal humerus fracture provides acceptable fixation and results in a similar range of shoulder motion. Although complication rates were low and insignificant between the two groups, a trend toward increased complications in the IMN group is noted.

Accuracy of detecting screw penetration of the radiocarpal joint following volar plating using plain radiographs versus computed tomography.

We compared standard and specialized plain radiographs with computed tomography (CT) for their ability to detect screw penetration of the articular surface of the distal radius in volar plating. Eight human cadaveric specimens were implanted with a fixed angle volar plate and 5 screws. Two groups were evaluated: (1) no articular screw penetration or (2) intra-articular screw penetration. Radiographs were obtained of each specimen. CT using 0.4 mm thickness slices were obtained and images were reconstructed in the sagittal and coronal planes. The radiographs and CTs were evaluated based on whether or not articular penetration occurred. The sensitivity, specificity, and accuracy of each radiographic modality were evaluated. CT was found to be much more sensitive and specific in detecting screw penetration than plain radiographs. The kappa (κ) statistic demonstrated "almost perfect interobserver agreement" based on CT readings, but only "substantial interobserver agreement based on plain radiographs." CT is more sensitive and specific and achieves a higher κ statistic than plain radiographs in detecting radiocarpal screw penetration after volar plating. CT should be used in detecting screw penetration when there is suspicion for radiocarpal joint penetration.

Intra- and periarticular heterotopic ossification in the knee after a low-velocity gunshot wound treated with retrograde intramedullary nailing of the femur.

This is a case of a 32-year-old man who developed intra- and periarticular heterotopic ossification (HO) after sustaining a low-velocity gunshot wound to the femur treated with intramedullary nailing of the fracture using a retrograde technique. The association between HO after a high-velocity gunshot wounds is well established. In addition, there have been two case reports of intra-articular HO after retrograde intramedullary femoral nailing. However, HO in and around the knee after a low-velocity gunshot wound has not been reported and may be more common than initially thought.

Helical blade vs telescoping lag screw for intertrochanteric fracture fixation.

The purpose of this study was to compare fixation stability and lag screw sliding characteristics between 2 different hip-nail lag screw designs, a telescoping screwbarrel and a solid helical blade. Simulated, unstable, 4-part intertrochanteric hip fractures were created in 6 pairs of cadaveric femurs. Each nail type was randomly assigned within each femur pair. Lag screw sliding and inferior and lateral head displacements were measured following an applied static load of 750 N. Measurements were obtained before, during, and after cyclical loading with 750 N for 105 cycles. Ultimate failure strength was determined. After considering inferior head displacements, no significant differences between the 2 screw designs were found. Mean head displacement for the helical screw was 2.18 mm, compared with 1.87 mm for the telescoping screw (P = .731). A significant difference in the amount of lateral movement of the lag screws was found, however. The helical lag screws had mean lateral sliding of 2.68 mm, compared with 0.25 mm for the telescoping screws (P = .007). Neither of the lag screw constructs failed by screw cutout from the head. Both screw designs provide similar fixation strength for stabilization of 4-part intertrochanteric fractures. Both the telescoping lag screw and the helical blade facilitate fracture collapse, but the telescoping lag screw also minimizes lateral projection of the screw from the nail. This advantage may help minimize postoperative lateral soft-tissue impingement.

Sliding of two lag screw designs in a highly comminuted fracture model.

A fracture construct, representing a worst-case model of a comminuted intertrochanteric fracture, was created in order to compare the fixation stability of two different cephalomedullary nails: one where the lag screw can telescope within itself to achieve displacement of the head-neck fragment, and the other where the solid lag screw slides only. After nail fixation, the models were loaded and then cycled, and positions of the head-neck fragment and lag screw were determined. Both nails similarly acted to limit motion of the head-neck fragment by the sliding of their lag screws, causing impingement of the fragment against the nail. Fragment movement was achieved with significantly less force with the telescoping lag screws, which also showed no final lateral projection from the nail. This was in contrast to the solid lag screws that demonstrated lateral projection in all cases.

Quantitative assessment of the bone morphogenetic protein expression from alternate bone graft harvesting sites.

OBJECTIVE: Bone morphogenetic proteins (BMPs) play important roles in the stimulation of osteogenesis and osteoinduction during bone fracture healing and their expression levels may be important for bone graft efficacy. The objective of this study was to determine if there are variations in the expression of BMPs and their receptors in various bone graft harvesting sites. We analyzed autogenous marrow aspirates obtained from three different graft sites for the mRNA levels of BMPs and their receptors. METHODS: Using real-time polymerase chain reaction, we analyzed the mRNA levels of BMPs and their receptors in autogenous bone marrow aspirates obtained from three different bone graft sites of 10 different human subjects. Collection of autogenous bone marrow from the iliac crest, the proximal humerus, and the proximal tibia was performed using standard sterile techniques in the operating room as part of surgery to treat an established fracture nonunion. RESULTS: The mRNA levels of BMP-2 and BMP-5 were the highest in the bone marrow aspirates from the three different sites, whereas the mRNA levels of the other osteoinductive BMPs (BMP-4, -5, -6, -7, -8, and -9) were lower. The mRNA levels of BMP-3, an inhibitor of osteogenesis, were the lowest in the bone marrow aspirates of all three different sites. There were no statistical significant differences in the mRNA levels of any of the BMPs or their receptors investigated in this study in the bone marrow of the three different sites. CONCLUSION: Because no statistical significant differences in the mRNA levels of the BMPs and their receptors were detected in the bone marrow aspirates from the three different sites, our findings suggest that potential differences of various graft sites in the augmentation of bone healing does not result from different expression levels of BMPs.

Prevalence of Staphylococcus aureus colonization in orthopaedic surgeons and their patients: a prospective cohort controlled study.

BACKGROUND: Methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus surgical site infections are an increasing health problem in the United States. To date, no study, as far as we know, has evaluated the prevalence of Staphylococcus aureus colonization in orthopaedic surgeons. The purpose of our study was to assess the prevalence of methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus colonization in orthopaedic surgery attending surgeons and residents at our institution compared with that in our high-risk patients. METHODS: We performed nasal swab cultures in seventy-four orthopaedic attending surgeons and sixty-one orthopaedic surgery residents at our institution, screening for methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus. We compared these results with a prospective database of nasal cultures of patients undergoing joint replacement and spine surgery. RESULTS: A total of 135 physicians were screened. Of those physicians, 1.5% were positive for methicillin-resistant Staphylococcus aureus and 35.7% were positive for methicillin-sensitive Staphylococcus aureus. None of the sixty-one residents were positive for methicillin-resistant Staphylococcus aureus. However, 59% were positive for methicillin-sensitive Staphylococcus aureus. Of the seventy-four attending surgeons, 2.7% were positive for methicillin-resistant Staphylococcus aureus and 23.3%, for methicillin-sensitive Staphylococcus aureus. Previous studies at our institution have demonstrated a 2.17% prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and an 18% rate of methicillin-sensitive Staphylococcus aureus in high-risk patients. Thus, no difference was found between the prevalence of methicillin-resistant Staphylococcus aureus in residents or attending surgeons and that in the high-risk patients. However, the prevalence of methicillin-sensitive Staphylococcus aureus colonization in the surgeons (35.7%) was significantly higher than that in the high-risk patient group (18%) (p < 0.01). CONCLUSIONS: At a major teaching hospital, a higher prevalence of methicillin-sensitive Staphylococcus aureus colonization was found among attending and resident orthopaedic surgeons compared with a high-risk patient group, but the prevalence of methicillin-resistant Staphylococcus aureus colonization was similar.

Pelvic osteomyelitis mimicking septic hip arthritis: a case report.

Peripelvic infections are rare, compared with the incidence of septic hip arthritis, but are serious, requiring emergent treatment. They often are not included in differential diagnoses for patients presenting with fever, pain, inability to bear weight, elevated white blood cell count, and elevated erythrocyte sedimentation rate. Most patients are treated initially as a septic hip arthritis. Early diagnosis and treatment are crucial to outcome in peripelvic abscess. Use of MRI may help to elucidate the correct diagnosis. Previously reported peripelvic infections included obturator internus and externus, and psoas, but to the best of our knowledge, this is first case report of infection of the ischiopubic ramus synchondrosis presenting as septic arthritis.