Effect of varus and valgus alignment on implant loading after proximal femur fracture fixation.

INTRODUCTION: More than 10 % of proximal femur fractures repaired with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN) demonstrate varus malreduction. The purpose of this study was to compare the effect of varus or valgus loading on comminuted intertrochanteric fractures repaired with SHS-P or SHS-IMN constructs. METHODS: Unstable intertrochanteric fractures with segmental comminution were generated in 12 cadaver proximal femurs, six of which were fixed with an SHS-P and six with an SHS-IMN. Both implants had a strain gauge at the lag screw-nail-plate interface to assess implant load bearing. The load on the implants was measured with the specimens in neutral position and at 5°, 10°, and 15° of varus and valgus. RESULTS: Loads on both SHS-IMN and SHS-P constructs were significantly increased when loading the implants in varus and significantly decreased when loading the implants in valgus. Unlike the SHS-IMN, the SHS-P trended toward increased load bearing at 15° varus (159.1 vs. 118.5 %, P = .065) and trended toward less load bearing at 15° valgus (42.3 vs. 59.8 %, P = .06). CONCLUSIONS: Regardless of implant choice, avoiding varus loading on the fixation construct reduces the load on the implant. SHS-P constructs may be more affected by varus or valgus malalignment than SHS-IMN constructs.

Smoking cessation and bone healing: optimal cessation timing.

Smoking is a worldwide epidemic. Complications related to smoking behavior generate an economic loss around $193 billion annually. In addition to impacting chronic health conditions, smoking is linked to increased perioperative complications in those with current or previous smoking history. Numerous studies have demonstrated more frequent surgical complications including higher rates of infection, poor wound healing, heightened pain complaints, and increased pulmonary morbidities in patients with a smoking history. Longer preoperative cessation periods also seem to correlate with reduced rates. At roughly 4 weeks of cessation prior to surgery, complication rates more closely reflect individuals without a smoking history in comparison with those that smoke within 4 weeks of surgery. In the musculoskeletal system, a similar trend has been observed in smokers with higher rates of fractures, nonunions, malunions, infections, osteomyelitis, and lower functional scores compared to non-smoking patients. Unfortunately, the present literature lacks robust data suggesting a temporal relationship between smoking cessation and bone healing. In our review, we analyze pseudoarthrosis rates following spinal fusion to suggest that bone healing in the context of smoking behavior follows a similar time sequence as observed in wound healing. We also discuss the implications for further clarity on bone healing and smoking cessation within orthopedics including improved risk stratification and better identification of circumstances where adjunct therapy is appropriate.

Time intervals in the treatment of fractured femurs as indicators of the quality of trauma systems.

OBJECTIVE: To investigate the use of time intervals in the treatment of fractured femurs as indicators of the quality of trauma systems. METHODS: Time intervals from injury to admission, admission to surgery and surgery to discharge for patients with isolated femur fractures in four low- and middle-income countries were compared with the corresponding values from one German hospital, an Israeli hospital and the National Trauma Data Bank of the United States of America by means of Student's t-tests. The correlations between the time intervals recorded in a country and that country's expenditure on health and gross domestic product (GDP) were also evaluated using Pearson's product moment correlation coefficient. FINDINGS: Relative to patients from high-income countries, those from low- and middle-income countries were significantly more likely to be male and to have been treated by open femoral nailing, and their intervals from injury to admission, admission to surgery and surgery to discharge were significantly longer. Strong negative correlations were detected between the interval from injury to admission and government expenditure on health, and between the interval from admission to surgery and the per capita values for total expenditure on health, government expenditure on health and GDP. Strong positive correlations were detected between the interval from surgery to discharge and general government expenditure on health. CONCLUSION: The time intervals for the treatment of femur fractures are relatively long in low- and middle-income countries, can easily be measured, and are highly correlated with accessible and quantifiable country data on health and economics.

Acute complications of patients with pelvic fractures after pelvic angiographic embolization.

BACKGROUND: Hemodynamically unstable patients with a pelvic fracture and arterial pelvic bleeding frequently are treated with pelvic angiographic embolization (PAE). PAE is reported to be a safe and effective method of controlling hemorrhage. However, the loss of blood supply and subsequent ischemia from embolization may lead to adverse consequences. OBJECTIVES/PURPOSES: We sought to determine (1) the frequency and types of complications observed after PAE; (2) the mortality after PAE; and (3) the clinical factors associated with complications and mortality after PAE. METHODS: We conducted a retrospective case series descriptive study at a Level I trauma center. Using our institution's trauma registry, we isolated patients with pelvic fractures treated with PAE admitted between June 1999 and December 2007. Complications attributed to PAE occurring in the initial hospital stay were recorded. We identified 98 patients with pelvic fractures treated by PAE with an average hospital stay of 25.3 days. RESULTS: The complication rate was 11% and included six patients with gluteal muscle necrosis (6%), five with surgical wound breakdown (5%), four deep infections (4%), one superficial infection, two patients with of impotence (2%), and one with bladder necrosis. The mortality rate in the PAE group reached 20%. Bilateral embolization was performed in 100% of the patients with complications. Nonselective embolization was performed in 81% of patients with complications. All of the patients with gluteal necrosis had bilateral nonselective embolization. CONCLUSIONS: Bilateral or nonselective PAE is associated with significant complications during the initial hospital stay. The value of PAE should be weighed against its possible adverse consequences. Selective unilateral arterial embolization should be considered whenever possible.

Rotational malreduction of the syndesmosis: reliability and accuracy of computed tomography measurement methods.

BACKGROUND: Computed tomography (CT)-based indices may be superior to plain radiographs in determining the adequacy of reduction following operative fixation of the syndesmosis in unstable ankle fractures. This study assessed the reliability and accuracy of four CT-based methods for measurement of rotational malreduction of the fibula. METHODS: A simulated Weber C ankle fracture was created by performing an osteotomy in 9 cadaver ankles. The fibula was rotated and fixed in neutral (0 degrees) and 10 to 30 degrees of internal and external rotation. Fifty-two CT images at the level of the syndesmosis were obtained in neutral and rotated positions and presented in random order to 3 independent observers. Measurements were made using commercial imaging software and 4 methods for interpreting CT scans. Interobserver reliability and accuracy were assessed and compared. RESULTS: Methods 1 and 4 showed high anatomic variability. Methods 1, 2, and 4 had a test-retest repeatability of about 15 degrees. Method 1 varied erratically with direction and degree of malrotation (R (2) = 0.15) and did not permit specification of a neutral range. Method 2 varied consistently and systematically with direction and degree of malrotation (R (2) = 0.88). Receiver operating characteristic curve analysis indicated that method 2 identified malrotation better than did the other methods. Methods 3 and 4 were somewhat more difficult to perform. CONCLUSIONS: Method 2, the angle between the tangent of the anterior tibial surface and the bisection of the vertical midline of the fibula at the level of the incisura, was fairly reliable and accurate and had greater ease of measurement compared with the other methods that were tested. CLINICAL RELEVANCE: This study demonstrated that assessment of malrotation of fibular fractures by CT scan can be difficult. We believe that of the 4 methods tested in this study, method 2, the angle between the tangent of the anterior tibial surface and the bisection of the vertical midline of the fibula at the level of the incisura, was the most useful.

Suprapatellar Tibial Nailing: Future or Fad?

Over the last hundred years, there have been significant advancements in the way the Orthopaedic community treats tibial fractures. More recently, the focus of Orthopaedic trauma surgeons has been comparing the different techniques of insertion for tibial nails, specifically suprapatellar (SPTN) versus infrapatellar. The existing literature is convincing that there does not appear to be any clinically significant differences between suprapatellar and infrapatellar tibial nailing, with some apparent benefits of SPTN. Based on the current body of literature and our personal experience with SPTN, we believe the suprapatellar tibial nail will become the future for most tibial nailing procedures, regardless of fracture pattern. We have seen evidence of improved alignment in both proximal and distal fracture patterns, decreased radiation exposure and operative time, relaxation of the deforming forces, ease of imaging, and static positioning of the leg, which would be helpful for the unassisted surgeon, as well as no difference in anterior knee pain or articular damage within the knee between the two techniques.

Tip apex distance, hip screw placement, and neck shaft angle as potential risk factors for cut-out failure of hip screws after surgical treatment of intertrochanteric fractures.

PURPOSE: To describe the quality of osteosynthesis after intertrochanteric fractures evaluation of tip apex distance (TAD) and position of the hip screw have been established. Furthermore, a slightly valgus fracture reduction has been suggested to reduce the risk of cut-out failure. However, uniform recommendations for optimal screw positioning and fracture reduction are still missing. The purpose of our study was to confirm potential risk factors for cut-out of hip screws of intertrochanteric fractures and to provide recommendations for practical clinical use. METHODS: A retrospective analysis of all patients with intertrochanteric fractures treated with a DHS or a gamma nail between January of 2007 and May of 2010 was performed at a level I trauma center. RESULTS: Two hundred thirty-five patients with intertrochanteric fractures after intra- and extramedullary stabilization were analyzed. A TAD of more than 25 mm was demonstrated to be the most important factor for cut-out in stable and unstable fractures. Fracture reduction with a valgus NSA of 5-10° was associated with a trend towards a lower rate of screw cut-out while an anterior placement of the screw (Parker's ratio index of <40) significantly increased cut-out incidence. CONCLUSIONS: According to our results, the TAD should not exceed 25 mm in stable (AO/OTA A1) as well as unstable (AO/OTA A2) fractures. An increased anterior hip screw placement should be avoided while fracture reduction with a slight valgus Neck Shaft seems favorable.

Limitations of standard fluoroscopy in detecting rotational malreduction of the syndesmosis in an ankle fracture model.

BACKGROUND: When treating ankle fractures with associated syndesmosis injury, failure to anatomically reduce the syndesmosis may lead to poor outcome. While shortening and posterior subluxation of the distal fibula are readily detected by intraoperative fluoroscopy, it is unclear how well malrotation can be assessed. The ability of fluoroscopy to detect rotational malreduction of the fibula was the subject of this study. MATERIALS AND METHODS: Distal fibula fractures with complete syndesmotic injury were produced in ten cadaveric ankles. Two Kirschner wires were used to fix the fibula in neutral (0 degrees), 10 to 30 degrees of external rotation (ER), and 10 degrees to 30 degrees of internal rotation (IR). Using C-arm fluoroscopy tibio-fibular clear space and tibio-fibular overlap in the AP and mortise views, and posterior fibular subluxation in the lateral view were measured to assess reduction of the syndesmosis. RESULTS: The radiographic indices were able to detect as little as 10 degrees of IR but were within their normal range in up to 30 degrees of ER. When assessing for a 2mm difference compared to the intact ankle, sensitivity of all indices were low after more than 15 degrees ER, but high and clinically useful after more than 15 degrees of IR. CONCLUSION: Radiographic indices for syndesmosis disruption could not detect ER malreduction of the syndesmosis of up to 30 degrees. CLINICAL RELEVANCE: In the setting of ankle fractures with syndesmosis disruption, fixing the fibula in as much as 30 degrees of external rotation may go undetected using intraoperative fluoroscopy alone.

Reporting on quality of reduction and fixation of intertrochanteric fractures-A systematic review.

BACKGROUND: Patient outcomes after intertrochanteric fracture fixation is the subject of a large body of published and ongoing clinical research. Fracture reduction and stable fixation are a pre-requisite for achieving optimal results. However, reporting on the quality of postoperative reduction and fixation, has been inconsistent in the literature on intertrochanteric fractures. The purpose of this study was to examine the quality and consistency of reporting of immediate postoperative reduction and fixation in clinical outcome studies of intertrochanteric fracture fixation. METHODS: Outcome studies of intertrochanteric fractures, published between 2001 and 2019, were identified using a PubMed. Six journals were identified as having a high impact on intertrochanteric fracture research by either having an impact factor greater than 3.0 or more than 30 published studies fulfilling inclusion criteria. Two independent reviewers reviewed each article for its reporting on immediate post-operative radiographic findings and whether an attempt was made to correlate these findings to outcomes. Quality and consistency of reduction reporting were assessed by recording the type and number of uniquely reported reduction metrics in all of the included studies. RESULTS: The reviewers identified 134 papers for the study, of which 110 (82%) reported on immediate postoperative radiographic findings. Of the papers reporting these findings, 84 (76%) reported quantitative measurements. Quantitative reporting changed from 79% in papers published between 2001-2014 to 86% in papers published between 2015-2019. Sixty-one (46%) papers reported Tip-Apex Distance, 56 (42%) reported degree of varus (compared to non-injured side), 42 (31%) reported Neck-Shaft Angle restoration, 31(23%) reported leg-length discrepancy, 18 (13%) reported rotation, 15(11%) reported on the status of the lateral wall, and 6 (4%) reported on calcar (medial buttress) reduction. Sixty-eight (51%) papers that measured reduction found an association between better immediate post-operative reduction and improved outcomes. CONCLUSIONS: Despite its recognized influence on outcomes of intertrochanteric fractures, leading peer-reviewed journals do not uniformly report on the immediate postoperative assessment of the quality of reduction and fixation. However, reporting has improved over the past five years. Standardized quantitative metrics will need to be reported in the future to allow meaningful comparisons between studies and accurate assessment of intertrochanteric fracture outcome.

Wire Placement in the Sustentaculum Tali Using a 2D Projection-Based Software Application for Mobile C-Arms: Cadaveric Study.

BACKGROUND: Indirect screw fixation of the sustentaculum tali in the lateral-medial direction can be challenging due to the complex calcaneal anatomy. A novel 2-dimensional (2D) projection-based software application detects Kirschner wires (K-wires) and visualizes their intended direction as a colored trajectory. The aim of this prospectively randomized cadaver study was to investigate whether the software would facilitate the indirect K-wire placement in the sustentaculum tali. METHODS: In 20 cadaver foot specimens, K-wires were placed indirectly in the sustentaculum tali by an experienced and an inexperienced surgeon, with and without using the application. Number of placement attempts, duration of procedure, fluoroscopy time, and number of individual fluoroscopy images were recorded. Each wire's position was analyzed in a 3-dimensional (3D) C-arm scan by an experienced blinded investigator. RESULTS: Use of the software by the inexperienced surgeon significantly reduced the number of placement attempts from 3.2 to 1.2 ( P = .006). The application also reduced operating time, from 273 s to 199 s ( P = .15), and fluoroscopy time, from 41 s to 29 s ( P = .15). Using the software, the experienced surgeon had a longer operating time (139 s to 183 s; P = .30), longer fluoroscopy time (5.6 s to 9.2 s; P = .17), and more individual fluoroscopy images (11.6 to 14.8; P = .30). Wire position did not show significant differences in both cases. CONCLUSION: During indirect K-wire placement in the sustentaculum tali, the software appeared to be a useful tool for the inexperienced surgeon. In our chosen study setting, the experienced surgeon did not benefit from the software. CLINICAL RELEVANCE: Possible indications for the software would be fractures of the proximal femur, sacrum, sacroiliac instabilities, vertebral bodies, scaphoid, Lisfranc joint, talus and calcaneus.

The Great Unknown-A systematic literature review about risk associated with intraoperative imaging during orthopaedic surgeries.

INTRODUCTION: Modern techniques in orthopaedic surgery using minimally invasive procedures, and increased use of fluoroscopic imaging present a potential increased risk to surgeons due to ionizing radiation exposure. This article is a systematic review of recent literature on radiation exposure of orthopaedic surgeons. MATERIALS AND METHODS: Pubmed and Cochrane searches were performed on intraoperative radiation exposure covering English and German articles published between 1.1.2000 and 11.8.2014. Inclusion criteria were clinical studies and systematic literature reviews focusing on radiation exposure of orthopaedic surgeons during surgical procedures of the musculoskeletal system reporting either effective dose (whole body) or equivalent dose at the organ level. All included articles were reviewed with focus on the surgical specialty, the procedure type, the imaging system used, the radiation measurement method, the fluoroscopy time, the radiation exposure, the use of radiation protection, and any references to specific safety guidelines. RESULTS: Thirty-four eligible publications were identified. However, the lack of well-designed studies focusing on radiation exposure of surgeons prevents pooling of data. Highest exposure and subsequent equivalent doses were reported from spinal surgery (up to 4.8mSv of equivalent dose to the hand) and intramedullary nailing (up to 0.142mSV of equivalent dose to the thyroid). Radiation exposure was reduced by 96.9% and 94.2% when wearing a thyroid collar and a lead apron. CONCLUSIONS: With the increasing use of intraoperative imaging, there is a growing need for radiation awareness by the operating surgeon. Strict adherence to radiation protection should be enforced to protect in-training surgeons. Strategies to reduce exposure include C-arm position, distance, protective wear, and new imaging technologies. Radiation exposure is harmful and action should be taken to minimize exposure.

Screw Stripping After Repeated Cortical Screw Insertion-Can We Trust the Cancellous "Bailout" Screw?

BACKGROUND: During osteosynthesis standard nonlocking cortical screws often require reinsertion, raising concern over possible decrease in their effectiveness. This study aims to quantify that potential loss of fixation with reinsertions as well as examine the ability of a cancellous "bailout screw" to regain insertion torque in a previously stripped screw hole. METHODS: Four different types of bone surrogates were chosen to represent normal cortical bone, osteoporotic cortical bone, high-density (normal) cancellous bone, and low-density (osteoporotic) cancellous bone; nonlocked 3.5-mm cortical screws were inserted into the predrilled holes 1, 2, 3, 4, or 5 times before being torqued maximally to the point of stripping. A 4.0-mm cancellous "bailout" screw was then placed into the same hole and torqued until stripping. Torque was measured continuously using a torque-measuring screwdriver and maximal insertion torque (MIT) of 3.5 and 4.0 screws before stripping was recorded. RESULTS: MIT decreased with reinsertion of nonlocked cortical screws. By the third reinsertion in all but the normal bone surrogates, the screws lost approximately one third to one half of their original MIT (50%-71% of original torque). The bailout screw succeeded in restoring the original MIT in the osteoporotic cancellous bone surrogate and the normal cortical bone surrogate. In the normal cancellous and osteoporotic cortical bone surrogates, the bailout screw was only able to restore an average of 50% (range 31%-63%) of the original MIT. CONCLUSIONS: Screw reinsertion may significantly reduce the MIT of 3.5-mm nonlocked cortical screws. Use of the bailout cancellous screw for a stripped cortical screw should be expected to restore MIT only in normal cortical bone and osteoporotic cancellous bone. In other scenarios, the bailout screw should not be expected to uniformly restore full insertion torque.

Short-term pelvic fracture outcomes in adolescents differ from children and adults in the National Trauma Data Bank.

BACKGROUND: Pediatric pelvic fractures are associated with high-energy trauma and injury to other systems, leading to an increased incidence of complication and mortality. Previous studies analyzed the pediatric population as a whole, including both children and adolescents. The purpose of this study was to examine whether adolescents with pelvic fracture have different complication and mortality rates compared to younger children and adults. METHODS: Using the National Trauma Data Bank, 37,784 patients below the age of 55 years with pelvic fractures were identified and divided into children (age <13 years), adolescents (age 13-17 years), and adults (age >17 years). Descriptive statistics and bivariate and multivariate analyses were performed. RESULTS: Children had an increased odds of death [odds ratio (OR) 2.29, 95 % confidence interval (CI) 1.96-2.67] and complications (OR 1.36, 95 % CI 1.20-1.55), whereas adolescents had a decrease in odds of death (OR 0.89, 95 % CI 0.74-1.06) and complications (OR 0.70, 95 % CI 0.61-0.81) compared to the adult population. CONCLUSIONS: Adolescents with pelvic fractures exhibit a different physiologic response to the children and adult populations. This emphasizes the need to distinguish these subpopulations in future epidemiological research and treatment planning.

Three-dimensional navigation is more accurate than two-dimensional navigation or conventional fluoroscopy for percutaneous sacroiliac screw fixation in the dysmorphic sacrum: a randomized multicenter study.

OBJECTIVES: To evaluate the accuracy of computer-assisted sacral screw fixation compared with conventional techniques in the dysmorphic versus normal sacrum. DESIGN: Review of a previous study database. SETTING: Database of a multinational study with 9 participating trauma centers. PATIENTS: The reviewed group included 130 patients, 72 from the navigated group and 58 from the conventional group. Of these, 109 were in the nondysmorphic group and 21 in the dysmorphic group. INTERVENTION: Placement of sacroiliac (SI) screws was performed using standard fluoroscopy for the conventional group and BrainLAB navigation software with either 2-dimensional or 3-dimensional (3D) navigation for the navigated group. MAIN OUTCOME MEASUREMENTS: Accuracy of SI screw placement by 2-dimensional and 3D navigation versus conventional fluoroscopy in dysmorphic and nondysmorphic patients, as evaluated by 6 observers using postoperative computerized tomography imaging at least 1 year after initial surgery. Intraobserver agreement was also evaluated. RESULTS: There were 11.9% (13/109) of patients with misplaced screws in the nondysmorphic group and 28.6% (6/21) of patients with misplaced screws in the dysmorphic group, none of which were in the 3D navigation group. Raw agreement between the 6 observers regarding misplaced screws was 32%. However, the percent overall agreement was 69.0% (kappa = 0.38, P < 0.05). CONCLUSIONS: The use of 3D navigation to improve intraoperative imaging for accurate insertion of SI screws is magnified in the dysmorphic proximal sacral segment. We recommend the use of 3D navigation, where available, for insertion of SI screws in patients with normal and dysmorphic proximal sacral segments. LEVEL OF EVIDENCE: Therapeutic level I.

The effect of fracture pattern stability on implant loading in OTA type 31-A2 proximal femur fractures.

BACKGROUND: Internal fixation of OTA type 31-A2 proximal femoral fractures can be performed with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN). Controversy exists as to which is the best implant for these types of fractures. The primary aim of this study was to investigate the stability of 31-A2 fractures as a function of loss of medial cortical buttress. The secondary aim was to assess the influence of fracture stability on the different internal fixation constructs. METHODS: Simulated simple intertrochanteric fractures were made in 12 cadaver proximal femurs. Six fractures were fixed with an SHS-P and 6 with an SHS-IMN. Both implants were instrumented with a strain gauge at the lag screw-nail/plate interface to allow assessment of implant load bearing (ILB). A primary fracture line, in accordance with the 31-A2 OTA classification, was created after which 3 subsequent horizontal osteotomies in 1-cm increments were made across the medial cortex. Compressive loading up to 1050 N was performed after each osteotomy. RESULTS: ILB was presented as percentage of maximal ILB. SHS-P constructs increased their load bearing gradually. For SHS-P constructs, ILB was 8.1% ± 1.8% in the intact state, increasing to 49.6% ± 14.0% after the initial intertrochanteric osteotomy (P = 0.0002), 68.7% ± 15.9% after the first medial osteotomy (P = 0.028), and 80.0% ± 15.9% after the second medial osteotomy (P = 0.15). After the first-level medial osteotomy, SHS-IMN constructs reached a plateau in which the implant carried the entire load. CONCLUSIONS: Type 31-A2 fractures become increasingly unstable with increased medial comminution (or fragment size). SHS-P constructs were more load sharing than SHS-IMN constructs. These findings may help guide the surgeon in choice of implant for a 31-A2 intertrochanteric fracture, leaning toward SHS-IMN for the more unstable fracture patterns.

Propensity for hip dislocation in normal gait loading versus sit-to-stand maneuvers in posterior wall acetabular fractures.

Treatment of posterior wall (PW) fractures of the acetabulum is guided by the size of the broken wall fragment and by hip instability. Biomechanical testing of hip instability typically is done by simulating the single-leg-stance (SLS) phase of gait, but this does not represent daily activities, such as sit-to-stand (STS) motion. We conducted a study to examine and compare hip instability after PW fractures in SLS and STS loading. We hypothesized that wall fragment size and distance from the dome (DFD) of the acetabulum to the simulated fracture would correlate with hip instability and, in the presence of a PW fracture, the hip would be more unstable during STS loading than during SLS loading. Incremental PW osteotomies were made in 6 cadaveric acetabula. After each osteotomy, a 1200-N load was applied to the acetabulum to simulate SLS and STS loading until dislocation occurred. All hip joints in the cadaveric models were more unstable in STS loading than in SLS loading. PW fragments at time of dislocation were larger (P<.001) in SLS loading (85% ± 13%; range, 81%-100%) than in STS loading (40% ± 7%; range, 33%-52%). Mean (SD) DFD at time of dislocation was 15.0 (3.5) mm (range, 14.4-19.6 mm) in STS loading and 5.3 (4.3) mm (range, 0.1-10.0 mm) in SLS loading (P<.04). There was more hip instability in STS loading than in SLS loading. In STS loading, hips dislocated with a PW fracture size of 33% or more and a DFD of 20 mm or less.

A method for detection of lateral malleolar malrotation using conventional fluoroscopy.

Recent studies on ankle syndesmosis injuries have shown that a significant amount of rotational malediction of the distal fibula are missed and may lead to poor functional outcome. A new set of radiographic criteria were developed to help detect distal fibula internal and external rotation using conventional fluoroscopy. The criteria were tested using a cadaveric model for Weber C ankle fractures fixed with the fibula in various degrees of internal and external rotation. Using the criteria orthopaedic trauma surgeons were able to improve their accuracy and agreement on assessment of degree and direction of fibula rotation.

The variable angle hip fracture nail relative to the gamma 3: a finite element analysis illustrating the same stiffness and fatigue characteristics.

Ten percent of the 250,000 proximal femur fractures that occur in the United States each year are malreduced into a varus position after treatment. Currently, there is no cephalomedullary nail available that allows the physician to dynamically change the lag-screw-to-nail angle. The Variable Angle Nail (VAN) was designed to allow movement of the lag screw relative to the shaft of the nail. This study compared the characteristics of the VAN to the Gamma 3 nail via finite element analysis (FEA) in stiffness and fatigue. The results of the FEA model with the same loading parameters showed the Gamma 3 and the VAN with lag-screw-to-nail angle of 120° to have essentially the same stiffness values ranging from 350 to 382 N/mm. The VAN with lag-screw-to-nail angles of 120°, 130°, and 140° should be able to withstand more than 1,000,000 cycles from 1,400 N to 1,500 N loading of the tip of the lag screw. The Gamma 3 should be able to last more than 1,000,000 cycles at 1,400 N. In summary, the VAN is superior or equivalent in stiffness and fatigue when compared to the Gamma 3 using FEA.

Reduction of pullout strength caused by reinsertion of 3.5-mm cortical screws.

INTRODUCTION: Osteosynthesis of the tibia, tibial plafond, and calcaneus is commonly performed with plates and 3.5-mm self-tapping cortical screws. Screw insertion and reinsertion within the same hole in the bone may occur during surgery. Therefore, the purpose of this study was to evaluate the pullout strength of 3.5-mm self-tapping screws with up to 5 re-insertions in the diaphysis of the tibia, metaphysis of the distal tibia, calcaneus, and a polyurethane synthetic bone model. METHODS: Screws were inserted into a synthetic bone model and 5 pairs of human cadaveric diaphyseal tibiae, distal tibiae, and calcanei. The bone was predrilled, and then 3.5-mm cortical self-tapping 316 L stainless steel screws with a washer were inserted bicortically. Screws were inserted from 1 to 5 times at each location. The screws were grasped and subjected to 5-mm/min tensional force via the biaxial material testing systems machine. Statistical significance was determined using a paired 2-tailed t test. RESULTS: There was a significant difference in the pullout strength of the tibial diaphysis (1710 ± 550 N), tibial metaphysis (471 ± 266 N), and calcaneus (238 ± 90 N; P < 0.01). The tibial diaphysis pullout strength was 1710 ± 550 N for one insertion differing significantly relative to the groups with 4 (average 1030 ± 543 N, P = 0.004) or 5 (average 364 ± 209 N, P < 0.001) insertions. The tibial metaphyseal pullout strength for the single insertion group was 471 ± 266 N and differed significantly relative to the 3 (P = 0.026), 4 (P = 0.044), and 5 (P = 0.042) insertion groups. The calcaneal pullout strength for the single insertion group was 238 ± 90 N with a significant difference of the 1, 3, and 4, versus the 5 insertion group (P = 0.027, 0.040, and 0.033, respectively). The synthetic bone model pullout strength decreased significantly from the one insertion group relative to all other insertion groups (group 1, 1167 ± 263 N; group 2, 768 ± 199 N; group 3, 694 ± 295 N; group 4, 662 ± 356 N; and group 5, 154 ± 183 N; P < 0.02). CONCLUSIONS: There is a significant decrease in relative pullout strength of 3.5-mm self-tapping cortical screws when comparing the tibial diaphysis, tibial metaphysis, and calcaneus. There is also a significant decrease in 3.5-mm self-tapping screw pullout strength after repeated reinsertions in the synthetic bone model, mid-shaft tibia, metaphyseal tibia, and calcaneus. We recommend that during osteosynthesis, careful screw insertion, and minimal reinsertion be performed.

Impact of a three-dimensional "hands-on" anatomic teaching module on acetabular fracture pattern recognition by orthopaedic residents.

BACKGROUND: Much of the difficulty in understanding acetabular fracture patterns is due to the complex three-dimensional relationship of the acetabulum to the greater pelvis. We hypothesized that combining three-dimensional "hands-on" anatomic models with two-dimensional informational teaching sheets would improve the ability of orthopaedic residents to accurately classify acetabular fracture patterns and aid in preoperative surgical approach selection. METHODS: Thirty-five orthopaedic residents from two programs accredited by the Accreditation Council for Graduate Medical Education participated in this prospective study. Twenty-question quizzes based on radiographs and computed tomography images of acetabular fractures tested the ability of the residents to accurately classify these fractures. One-half of the residents had access to informational teaching sheets only, and the other group had access to three-dimensional pelvic models of the fractures in addition to the informational sheets. RESULTS: There was a positive correlation between the postgraduate year in training and the mean pre-intervention quiz score (r2 = 0.89). The mean improvement in the quiz score was 15% ± 15% for first and second-year residents compared with 3% ± 12% for fourth and fifth-year residents (p = 0.04). The resident group that used the three-dimensional "hands-on" models showed greater post-intervention improvement in the quiz score. CONCLUSIONS: In this preliminary study, active learning that incorporated three-dimensional "hands-on" pelvic models improved the ability of orthopaedic residents to accurately classify acetabular fracture patterns compared with use of informational teaching sheets alone.