Amir Matityahu

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 malre-duction 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.

Prediction of postoperative knee flexion in Insall-Burstein II total knee arthroplasty.

Postoperative knee flexion in patients undergoing Insall-Burstein-II total knee arthroplasty at 2 years was evaluated regarding two basic questions: what groups of patients gain or lose the most flexion and what groups of patients have the best or worst postoperative flexion. Thirteen preoperative variables (maximum flexion, flexion arc, tibiofemoral angle, quadriceps strength, extensor lag, Knee Society score, Knee Society patient assessment, gender, age, height, weight, diagnosis, and surgeon) and four postoperative variables (leg length change, tibiofemoral angle, distance from patella to the joint line, and the tibial prosthesis anteroposterior translation on a lateral radiograph) were used in an attempt to explain postoperative flexion. The analysis was performed on 164 consecutive Insall-Burstein-II total knees in which the data were gathered prospectively on a time oriented medical record database. A regression tree analysis was used to identify several groups of patients, characterized by preoperative factor values, who had markedly above average performance on postoperative flexion. The preoperative factors identified include preoperative flexion, flexion arc, tibiofemoral angle, extensor lag, diagnosis, and age. The only postoperative variable of significance was tibiofemoral angle. Among the potential determinants of postoperative flexion that failed to appear predictive were the Knee Society scores and surgeon. Preoperative flexion is known to be a critical determinant of postoperative flexion in total knee replacement. However, in the current study, preoperative flexion accounted for only half of the difference between the best (122°) and the worst (88°) group, as determined with regression tree analysis.

The distal semimembranosus complex: normal MR anatomy, variants, biomechanics and pathology

ObjectiveTo describe the normal MR anatomy and variations of the distal semimembranosus tendinous arms and the posterior oblique ligament as seen in the three orthogonal planes, to review the biomechanics of this complex and to illustrate pathologic examples.Results and conclusionThe distal semimembranosus tendon divides into five tendinous arms named the anterior, direct, capsular, inferior and the oblique popliteal ligament. These arms intertwine with the branches of the posterior oblique ligament in the posterior medial aspect of the knee, providing stability. This tendon-ligamentous complex also acts synergistically with the popliteus muscle and actively pulls the posterior horn of the medial meniscus during knee flexion. Pathologic conditions involving this complex include complete and partial tears, insertional tendinosis, avulsion fractures and bursitis.

Does a volar locking plate provide equivalent stability as a dorsal nonlocking plate in a dorsally comminuted distal radius fracture?: a biomechanical study.

Objectives: The purpose of this study was to compare the fixation afforded by a dorsal nonlocking plate with a volar locking plate in a fracture model simulating an extra-articular distal radius fracture with dorsal comminution (OTA [Orthopaedic Trauma Association] type 23-A3.2). Methods: In 10 matched pairs of fresh-frozen cadaveric arms, a comminuted extra-articular dorsally unstable distal radius fracture (OTA type 23-A3.2) was created. The fractures were fixed with either dorsally placed nonlocking T-plate or volarly placed locking plate within matched pairs. The precycling stiffness with axial and torsional loading of the specimens was determined. The specimens were then loaded axially for 5000 cycles, and postcycling axial and torsional stiffness and load to failure were determined. Results: The mean axial and torsional stiffness before and after cyclic loading of fractures stabilized with dorsal nonlocking plate was not significantly different than fractures fixed with volar locking plate. Although the mean load to failure was greater for the volar locking plate group than dorsal nonlocking plate group, the difference was not significant. Conclusions: This study suggests that the fixation obtained with volar locking plates is as stable as fixation with a dorsal plate in acute healing period and can withstand the functional demands of the immediate postoperative period in dorsally comminuted unstable extra-articular distal radius fractures. Elimination of dorsal tendinopathy by using volar locking plates may lead to fewer long-term complications. Locking plates provided better stability in specimens with osteoporosis.

Tibial plateau fracture repairs augmented with calcium phosphate cement have higher in situ fatigue strength than those with autograft.

Objectives: This study compared the biomechanical fatigue strength of calcium phosphate augmented repairs versus autogenous bone graft (ABG) repairs in lateral tibia plateau fractures. Methods: Eight matched pairs of tibias (six male, two female; age, 75 ± 14 years) were harvested from fresh-frozen cadavers. Reproducible split-depression fractures were simulated and repaired by an orthopaedic traumatologist using a lateral tibial plateau plate. One tibia from each donor was randomly assigned to either calcium phosphate (Callos; Acumed, Hillsboro, OR) or ABG as augmentation. The femoral component of a hemitotal knee arthroplasty was attached to the actuator of a servohydraulic press and centered above the repair site. Cyclic, physiological compression loads were applied at 4Hz starting with a maximum load of 15% body weight and increasing by 15% body weight every 70,000 cycles. Loading conditions were determined from calculations of weight distribution, joint contact area, and gait characterization from existing literature. Repair site depression and stiffness were measured at regular intervals. Specimens were then loaded to failure at 1 mm/min. Results: Calcium phosphate augmented repairs subsided less and were more stiff during the fatigue loading than were ABG repairs at the 70,000, 140,000, and 210,000 cycle intervals (P < 0.03) All repairs survived to 210,000 cycles. The average ultimate load of the calcium phosphate repairs was 2241 ± 455 N (N = 6) and 1717 ± 508 N (N = 8) for ABG repairs (P = 0.02). Conclusion: Calcium phosphate repairs have significantly higher fatigue strength and ultimate load than ABG repairs and may increase the immediate weightbearing capabilities of the repaired knee.

Acute Complications of Patients With Pelvic Fractures After Pelvic Angiographic Embolization

BackgroundHemodynamically 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/purposesWe 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.MethodsWe 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.ResultsThe 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.ConclusionsBilateral 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.Level of EvidenceLevel IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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 (R2 = 0.15) and did not permit specification of a neutral range. Method 2 varied consistently and systematically with direction and degree of malrotation (R2 = 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.

Superior Gluteal Artery Injury During Iliosacral Screw Placement due to Aberrant Anatomy

Percutaneous iliosacral screws are considered the standard of care for disruptions of the sacroiliac joint. This article describes a case of iatrogenic injury to the superior gluteal artery during iliosacral screw insertion and analyzes the possible reasons for this complication.A 32-year-old man diagnosed with an unstable pelvic ring injury underwent percutaneous fixation of the right sacroiliac joint. A 2-cm skin incision was made, and a straight cannulated awl was placed with the tip directly lateral to the S1 body. A guide wire was inserted and a partially threaded 6.5-mm cannulated screw with a washer was then placed over the guide wire and was found to be in excellent position. At this time, increased bleeding from the incision was observed. The incision was enlarged and dissection was carried down through the muscle. The bleeding vessel could not be visualized. Therefore, the wound was packed with sponges, and coil embolization of the right superficial gluteal artery was successfully performed.Analysis of the angiography reveled that our patients superficial branch of the superior gluteal artery measured more than twice the average length reported in a previous anatomic study. We believe this is the first case of superior gluteal artery bleeding due to aberrant superior gluteal artery anatomy. When planning iliosacral screw insertion, the possibility of anatomical variance of the superior gluteal artery should be acknowledged and sought after in preoperative angiography, when available.

Survivorship and Severe Complications Are Worse for Octogenarians and Elderly Patients with Pelvis Fractures as Compared to Adults: Data from the National Trauma Data Bank

Purpose. This study examined whether octogenarians and elderly patients with pelvic fractures have a different risk of complication and mortality as compared to adults. Methods. Data was gathered from the National Trauma Data Bank from 2002 to 2006. There were 32,660 patients 18–65, 6,408 patients 65–79, and 5,647 patients ≥ 80 years old with pelvic fractures. Descriptive statistics and bivariate and multivariate analyses were performed with the adult population as a referent. Results. Multivariate analysis showed 4.7-fold higher odds of death and 4.57 odds of complications in the octogenarian group after a pelvic fracture compared to adults. The elderly had 1.81-fold higher odds of death and 2.18-fold higher odds of severe complications after sustaining a severe pelvic fracture relative to adults. An ISS ≥ 16 yielded 15.1-fold increased odds of mortality and 18.3-fold higher odds of severe complications. Hypovolemic shock had 7.65-fold increased odds of death and 6.31-fold higher odds of severe complications. Between the ages of 18 and 89 years, there is approximately a 1% decrease in survivorship every 10 years. Conclusions. This study illustrates that patients older than 80 years old with pelvis fractures have a higher mortality and complications rate than elderly or adult patients.

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. See Instructions for Authors for a complete description of levels of evidence.