The Experts below are selected from a list of 11583 Experts worldwide ranked by ideXlab platform
Surena Namdari - One of the best experts on this subject based on the ideXlab platform.
-
failure to restore the calcar and locking screw cross threading predicts varus collapse in proximal Humerus Fracture fixation
Journal of Shoulder and Elbow Surgery, 2020Co-Authors: Eric M Padegimas, Gerard Chang, Kamran Namjouyan, Surena NamdariAbstract:Background Varus collapse is a common failure mode of proximal Humerus Fracture (PHF) fixation. The purpose of this study was to analyze predictors of varus collapse of PHF after open reduction, internal fixation (ORIF). Methods All patients who underwent ORIF of a PHF from January 2008 to July 2018 were identified. Known predictors of fixation failure were assessed, including calcar distance, calcar ratio, and calcar restoration. Additionally, the presence of cross-threaded screws was determined. The primary outcome analyzed was varus collapse of the Fracture defined as a change in neck shaft angulation to less than 120°. Results There were 112 patients identified who underwent ORIF of a PHF that met inclusion criteria. The population was 75.0% female (84/112), average age was 62.5 ± 10.4 years (range 40.0-87.9), and average body mass index was 28.0 ± 5.5 (17.5-46.4). There were 17 with varus collapse. In 11 of the 17 patients (64.7%), there was screw cross-threading (vs. 31/95 [32.6%] in those that did not collapse); P = .012. In addition, 8 of the 17 (47.1%) did not have restoration of the calcar (vs. 16/95 [16.8%]; P = .005). Conclusion This study identifies 2 surgeon-controlled variables that can contribute to varus collapse after ORIF of PHFs. Cross-threading of locking screws and failure to restore the medial calcar can be a function of implant design, surgeon technical skill, and/or bone quality.
-
calcar screw position in proximal Humerus Fracture fixation don t miss high
Injury-international Journal of The Care of The Injured, 2018Co-Authors: Samir Mehta, Jennifer Sanville, Matthew Chin, Surena Namdari, Michael W HastAbstract:Abstract Introduction In locked plate fixation of proximal Humerus Fractures, the calcar is an important anchor point for screws providing much-needed medial column support. Most locking plate implants utilize a fixed-trajectory locking screw to achieve this goal. Consequently, adjustments of plate location to account for patient-specific anatomy may result in a screw position outside of the calcar. To date, little is known about the consequences of “missing” the calcar during plate positioning. This study sought to characterize the biomechanics associated with proximal and distal placement of locking plates in a two-part Fracture model. Materials and methods This experiment was performed twice, first with elderly cadaveric specimens and again with osteoporotic sawbones. Two-part Fractures were simulated and specimens were divided to represent proximal, neutral, and distal plate placements. Non-destructive torsional and axial compression tests were performed prior to an axial fatigue test and a ramp to failure. Torsional stiffness, axial stiffness, humeral head displacement and stiffness during fatigue testing, and ultimate load were compared between groups. Results Cadavers: Proximal implant placement led to trends of decreased mechanical properties, but there were no significant differences found between groups. Sawbones: Distal placement increased torsional stiffness in both directions (p = 0.003, p = 0.034) and axial stiffness (p = 0.018) when compared to proximal placement. Distal placement also increased torsional stiffness in external rotation (p = 0.020), increased axial stiffness (p = 0.024), decreased humeral head displacement during fatigue testing, and increased stiffness during fatigue testing when compared to neutral placement. Discussion The distal and neutral groups had similar mechanical properties in many cadaveric comparisons while the proximal group trended towards decreased construct stiffness. Results from the Sawbones model were more definitive and provided further evidence that proximal calcar screw placements are undesirable and distal implant placement may provide improved construct stability. Conclusion Successful proximal Humerus Fracture reconstruction is inherent upon anatomic Fracture reduction coupled with medial column support. Results from this experiment suggest that missing the calcar proximally is deleterious to fixation strength, while it is safe, and perhaps even desirable, to aim slightly distal to the intended target.
-
defining optimal calcar screw positioning in proximal Humerus Fracture fixation
Journal of Shoulder and Elbow Surgery, 2017Co-Authors: Eric M Padegimas, Cassandra Lawrence, Thema Nicholson, Aaron Palmquist, Benjamin Zmistowski, Surena NamdariAbstract:Background Anatomic reduction and placement of an inferior calcar screw are strategies to prevent fixation failure in proximal Humerus factures. Optimal position of the calcar screw remains unknown. Methods There were 168 shoulders (68.5% female; average age, 63.6 ± 11.5 years) that underwent open reduction and internal fixation of a displaced proximal Humerus Fracture involving the surgical or anatomic neck. Univariate and multivariate analyses were performed on preoperative clinical, preoperative radiographic, and postoperative radiographic variables to determine association with fixation failure. A receiver operating characteristic curve was performed to determine a maximum distance from the inferior screw to the calcar (“calcar distance”) as well as a maximum ratio of this distance and the head diameter (“calcar ratio”). Results There were 26 of 168 (15.5%) patients with radiographic failures (19 related to fixation failure). Univariate analysis and multivariate analyses found quality of reduction (P Conclusions Quality of reduction, calcar distance, and calcar ratio independently correlated with fixation failure. This study provides optimal distances and ratios for calcar screw placement that can be used clinically.
Michael W Hast - One of the best experts on this subject based on the ideXlab platform.
-
mechanical effects of bone substitute and far cortical locking techniques in 2 part proximal Humerus Fracture reconstruction a cadaveric study
Journal of Orthopaedic Trauma, 2020Co-Authors: Michael W Hast, Jennifer Sanville, Matthew Chin, Elaine C Schmidt, George Karl Van Osten, Samir MehtaAbstract:OBJECTIVES To make direct comparisons of the biomechanical properties of a control (CTL) group and implants that were augmented with far cortical locking (FCL), bone substitute material (BSM), and a combination of both (ALL) to determine which fixation is most effective in reducing implant failure. METHODS The constructs were tested with osteopenic cadaveric specimens in a two-part Fracture model. Specimens were subjected to a battery of nondestructive torsion and axial compression tests, followed by a cyclic test. Construct stiffness and cycles to failure were documented, pre- and post-test fluoroscopy was performed, and implant and bone kinematics were quantified. RESULTS During nondestructive testing, the BSM group exhibited significantly increased torsional and axial stiffness compared with the FCL (P = 0.006, P < 0.001) group and ALL group (P < 0.001, P = 0.006). There were no significant differences in resistance to cyclic loading between groups. Fluoroscopic analysis indicated significant differences in the motions of nonlocked cannulated screws (used in BSM and ALL) versus locked screws (used in CTL and FCL). CONCLUSIONS Patients with poor bone quality and proximal Humerus Fracture may necessitate added compliance or rigidity to achieve fixation. Both have exhibited favorable biomechanical characteristics in this cadaveric 2-part proximal Humerus Fracture model.
-
Biomechanical Testing of Additive Manufactured Proximal Humerus Fracture Fixation Plates
Annals of Biomedical Engineering, 2019Co-Authors: Maryam Tilton, April Armstrong, Jennifer Sanville, Matthew Chin, Michael W Hast, Gregory S. Lewis, Guha P. ManogharanAbstract:Achieving satisfactory Fracture fixation in osteoporotic patients with unstable proximal Humerus Fractures remains a major clinical challenge. Varus collapse is one of the more prominent complications that may lead to screw cutout. This aim of this study was to compare the fixation provided by conventional locking plates with novel design concepts that are only feasible through additive manufacturing (AM) techniques. In addition to reversed engineered implants, two novel implant designs with integrated struts were included in the study to provide medial support to humeral head. The medial strut was either solid or included a porous lattice structure intended to promote bone ingrowth. Biomechanical tests were performed using low density synthetic bones with simulated 3-part comminuted Fractures. Nondestructive torsion and compression were performed, followed by increasing cyclic loading. The relative displacements between the bone fragments were determined using a 3D motion capture system. The AM manufactured implants with medial strut showed significant reduction of varus displacement during the increasing cyclic loading when compared to conventional designs. AM reversed-engineered locking plates showed similar mechanical behavior to conventional plates with identical geometry. This study demonstrates the feasibility and potential of employing alternative design via AM for fixation of unstable comminuted proximal Humerus Fractures to reduce fragment displacement.
-
calcar screw position in proximal Humerus Fracture fixation don t miss high
Injury-international Journal of The Care of The Injured, 2018Co-Authors: Samir Mehta, Jennifer Sanville, Matthew Chin, Surena Namdari, Michael W HastAbstract:Abstract Introduction In locked plate fixation of proximal Humerus Fractures, the calcar is an important anchor point for screws providing much-needed medial column support. Most locking plate implants utilize a fixed-trajectory locking screw to achieve this goal. Consequently, adjustments of plate location to account for patient-specific anatomy may result in a screw position outside of the calcar. To date, little is known about the consequences of “missing” the calcar during plate positioning. This study sought to characterize the biomechanics associated with proximal and distal placement of locking plates in a two-part Fracture model. Materials and methods This experiment was performed twice, first with elderly cadaveric specimens and again with osteoporotic sawbones. Two-part Fractures were simulated and specimens were divided to represent proximal, neutral, and distal plate placements. Non-destructive torsional and axial compression tests were performed prior to an axial fatigue test and a ramp to failure. Torsional stiffness, axial stiffness, humeral head displacement and stiffness during fatigue testing, and ultimate load were compared between groups. Results Cadavers: Proximal implant placement led to trends of decreased mechanical properties, but there were no significant differences found between groups. Sawbones: Distal placement increased torsional stiffness in both directions (p = 0.003, p = 0.034) and axial stiffness (p = 0.018) when compared to proximal placement. Distal placement also increased torsional stiffness in external rotation (p = 0.020), increased axial stiffness (p = 0.024), decreased humeral head displacement during fatigue testing, and increased stiffness during fatigue testing when compared to neutral placement. Discussion The distal and neutral groups had similar mechanical properties in many cadaveric comparisons while the proximal group trended towards decreased construct stiffness. Results from the Sawbones model were more definitive and provided further evidence that proximal calcar screw placements are undesirable and distal implant placement may provide improved construct stability. Conclusion Successful proximal Humerus Fracture reconstruction is inherent upon anatomic Fracture reduction coupled with medial column support. Results from this experiment suggest that missing the calcar proximally is deleterious to fixation strength, while it is safe, and perhaps even desirable, to aim slightly distal to the intended target.
Kenneth A Egol - One of the best experts on this subject based on the ideXlab platform.
-
Some outcomes of patients treated operatively for distal Humerus Fractures are affected by hand dominance
European Journal of Orthopaedic Surgery & Traumatology, 2021Co-Authors: Charlotte N. Shields, Sanjit R Konda, Joseph R. Johnson, Jack M. Haglin, Kenneth A EgolAbstract:Purpose This study sought to compare postoperative outcomes and complications between patients with distal Humerus Fractures treated with open reduction and internal fixation (ORIF) of their non-dominant versus dominant arm. Methods A retrospective review of all patients who sustained a distal Humerus Fracture treated operatively with ORIF at one academic institution between 2011 and 2015 was performed. Measured outcomes included complications, time to Fracture union, painful hardware, removal of hardware, Mayo Elbow Performance Index (MEPI), and elbow range of motion. Differences in outcomes between patients who underwent surgery of their dominant upper extremity and those who underwent surgery of their non-dominant extremity were assessed. Results Sixty-nine patients met inclusion criteria. Forty (58.0%) underwent ORIF of a distal Humerus Fracture on their non-dominant arm and 29 (42.0%) on their dominant arm. Groups did not differ with respect to demographics, injury information, or surgical management. Mean overall follow-up was 14.1 ± 10.5 months, with all patients achieving at least 6 months follow-up. The non-dominant cohort experienced a higher proportion of postoperative complications ( P = 0.048), painful hardware ( P = 0.018), and removal of hardware ( P = 0.002). At latest follow-up, the non-dominant cohort had lower MEPI scores ( P = 0.037) but no difference in elbow arc of motion ( P = 0.314). Conclusion Patients who sustained a distal Humerus Fracture of their non-dominant arm treated with ORIF experienced more postoperative complications, reported a greater incidence of painful hardware, underwent removal of hardware more often, and had worse functional recovery in this study. Physicians should emphasize the importance of physical therapy and maintaining arm movement especially when the non-dominant arm is involved following distal Humerus Fracture repair. Level of evidence Level III.
-
Repair of proximal Humerus Fracture nonunions using a standardized treatment algorithm: a case series
European Journal of Orthopaedic Surgery & Traumatology, 2021Co-Authors: Kurtis D. Carlock, Sanjit R Konda, Isabella R. Bianco, Joseph D. Zuckerman, Kenneth A EgolAbstract:Background Nonunion of Fractures about the proximal Humerus represents a rare and complex problem. The purpose of this study was to evaluate the clinical and functional outcomes following proximal Humerus Fracture (PHF) nonunion repair using a plate and screw construct with a direct comparison to those experienced following operative fixation of acute PHF using a plate and screw construct. Methods Two separate patient cohorts were included in this study. The first consisted of 16 patients diagnosed with a non-united PHF who underwent operative nonunion repair treated with a standard algorithmic approach. The comparison group consisted of 173 patients who achieved union following initial open reduction and internal fixation of an acute PHF treated with a proximal Humerus locking plate construct. All patients had at least 12 months of postoperative follow-up. Outcomes were assessed for both groups using American Shoulder and Elbow Surgeons (ASES) scores, visual analog scale (VAS) pain scores, and postoperative shoulder range of motion (ROM). Statistical analyses were used to compare these outcome measures between the two cohorts. Results The nonunion repair cohort consisted of eleven surgical neck nonunions and five nonunions of both the surgical neck and greater tuberosity. Ten patients had undergone surgical treatment for their original Fracture, while six were initially treated non-operatively. All patients had Boileau type 3 sequelae of their proximal Humerus Fracture. Union was achieved in all patients at a mean of 5.4 months following nonunion repair. Complications included hardware failure requiring revision in two patients (12.5%) and avascular necrosis requiring conversion to anatomic total shoulder arthroplasty following union in one patient (6.3%). The nonunion repair and acute Fracture cohorts did not differ with respect to mean ASES scores, VAS pain scores, or active shoulder ROM at any postoperative time point. Conclusion Surgical repair of PHF nonunion is a viable treatment strategy that can lead to consistent bony healing with outcomes comparable to those of patients who achieve Fracture union following initial surgical repair of an acute proximal Humerus Fracture. Surgeons should be cognizant of mechanical considerations that may lead to early failure.
-
total shoulder arthroplasty for proximal Humerus Fracture is associated with increased hospital charges despite a shorter length of stay
Orthopaedics & Traumatology-surgery & Research, 2016Co-Authors: Arthur Manoli, Christina E Capriccioso, Sanjit R Konda, Kenneth A EgolAbstract:Abstract Background Operation choice is a complex decision in the surgical management of proximal Humerus Fractures. Recently, there has been an increase in the use of total shoulder arthroplasty (TSA) for complex Fracture patterns. Hypothesis Patients with proximal Humerus Fractures who receive TSA are more likely to have higher hospital charges and a prolonged length of stay relative to patients receiving hemiarthroplasty (HA), open reduction with internal fixation (ORIF) or closed reduction with internal fixation (CRIF). Materials and methods A statewide electronic database was used to identify 13,316 hospital admissions from 2000–2011 were a proximal Humerus Fracture was surgically managed in an effort to determine the effect of operation choice on cost and length of stay. A univariate analysis was preformed to examine overall trends in surgical management. Additionally, a periodic, multivariate logistic regression analysis was used to determine how operation choice affected the odds of a high cost hospital stay or a prolonged length of stay after controlling for age, comorbidity burden, gender, and insurance type. Results After controlling for confounding factors, patients receiving total shoulder arthroplasty (TSA) were 2.25 times more likely to have high total hospital charges than patients receiving HA and 3.21 times more likely than patients receiving ORIF. Additionally, TSA was found to be a significant negative predictor of prolonged length of stay (pLOS). HA, ORIF and CRIF did not significantly predict pLOS. Discussion The use of TSA for acute proximal Humerus Fractures is associated with increased hospital costs despite a shorter length of stay when compared to other operative choices. As reverse total shoulder arthroplasty becomes more popular for treatment of this injury, it is important that functional outcomes be interpreted in the context of relative cost trade-offs. Level of evidence Level IV.
David L Skaggs - One of the best experts on this subject based on the ideXlab platform.
-
a new surgical technique for the treatment of supracondylar Humerus Fracture malunions in children
Journal of Children's Orthopaedics, 2011Co-Authors: David L Skaggs, David M Glassman, Jennifer M Weiss, Robert M KayAbstract:Purpose To report a new locking lateral closing wedge osteotomy used in repairing pediatric supracondylar Humerus Fracture malunions, which allows for coronal and sagittal plane correction of both cubitus varus and extension.
-
risk factors for vascular repair and compartment syndrome in the pulseless supracondylar Humerus Fracture in children
Journal of Pediatric Orthopaedics, 2010Co-Authors: Paul D Choi, Rojeh Melikian, David L SkaggsAbstract:Background The aims of this study were to determine how often Fracture reduction alone restored pulses and vascular perfusion in displaced supracondylar Humerus Fractures with absent distal pulses on presentation, and whether any preoperative factors were associated with the need for vascular repair and vascular complications. Methods We reviewed 1255 supracondylar Humerus Fractures in children treated operatively over 12 years at one institution. We identified 33 patients who presented with displaced supracondylar Humerus Fractures and absent distal pulses. We reviewed the management and outcome of these injuries. Results Thirty-three (of 1255) patients presented with a pulseless supracondylar Humerus Fracture (2.6%). The patients were divided into 2 groups: those at presentation whose hand was well perfused (n=24) or poorly perfused (9). None (0 of 24) of the well-perfused patients underwent vascular repair; 3 had open reduction. Of the 21 well-perfused patients undergoing closed reduction and pinning, 11 (of 21) had a palpable pulse after surgery and 10 (of 21) remained pulseless but well perfused; all did well clinically. Of the 9 patients in the poorly perfused group, 4 underwent vascular repair, and compartment syndrome developed in 2 during the postoperative period. In just over half of patients with a poorly perfused hand (5 of 9), Fracture reduction alone was the definitive treatment. Conclusions In the largest series of children with pulseless displaced supracondylar Humerus Fractures in the literature, we identify 2 distinct populations, with the perfusion status of the hand at time of presentation correlating significantly with the ultimate need for vascular repair. In patients presenting with a well-perfused hand, Fracture reduction alone was sufficient treatment in all 24 (of 24) cases, and no patients developed compartment syndrome. Nearly half of these patients still had an absent palpable pulse but well-perfused hand after closed reduction, yet did well clinically. Patients presenting with a poorly perfused hand are at high risk for vascular repair and compartment syndrome.
Eric M Padegimas - One of the best experts on this subject based on the ideXlab platform.
-
failure to restore the calcar and locking screw cross threading predicts varus collapse in proximal Humerus Fracture fixation
Journal of Shoulder and Elbow Surgery, 2020Co-Authors: Eric M Padegimas, Gerard Chang, Kamran Namjouyan, Surena NamdariAbstract:Background Varus collapse is a common failure mode of proximal Humerus Fracture (PHF) fixation. The purpose of this study was to analyze predictors of varus collapse of PHF after open reduction, internal fixation (ORIF). Methods All patients who underwent ORIF of a PHF from January 2008 to July 2018 were identified. Known predictors of fixation failure were assessed, including calcar distance, calcar ratio, and calcar restoration. Additionally, the presence of cross-threaded screws was determined. The primary outcome analyzed was varus collapse of the Fracture defined as a change in neck shaft angulation to less than 120°. Results There were 112 patients identified who underwent ORIF of a PHF that met inclusion criteria. The population was 75.0% female (84/112), average age was 62.5 ± 10.4 years (range 40.0-87.9), and average body mass index was 28.0 ± 5.5 (17.5-46.4). There were 17 with varus collapse. In 11 of the 17 patients (64.7%), there was screw cross-threading (vs. 31/95 [32.6%] in those that did not collapse); P = .012. In addition, 8 of the 17 (47.1%) did not have restoration of the calcar (vs. 16/95 [16.8%]; P = .005). Conclusion This study identifies 2 surgeon-controlled variables that can contribute to varus collapse after ORIF of PHFs. Cross-threading of locking screws and failure to restore the medial calcar can be a function of implant design, surgeon technical skill, and/or bone quality.
-
defining optimal calcar screw positioning in proximal Humerus Fracture fixation
Journal of Shoulder and Elbow Surgery, 2017Co-Authors: Eric M Padegimas, Cassandra Lawrence, Thema Nicholson, Aaron Palmquist, Benjamin Zmistowski, Surena NamdariAbstract:Background Anatomic reduction and placement of an inferior calcar screw are strategies to prevent fixation failure in proximal Humerus factures. Optimal position of the calcar screw remains unknown. Methods There were 168 shoulders (68.5% female; average age, 63.6 ± 11.5 years) that underwent open reduction and internal fixation of a displaced proximal Humerus Fracture involving the surgical or anatomic neck. Univariate and multivariate analyses were performed on preoperative clinical, preoperative radiographic, and postoperative radiographic variables to determine association with fixation failure. A receiver operating characteristic curve was performed to determine a maximum distance from the inferior screw to the calcar (“calcar distance”) as well as a maximum ratio of this distance and the head diameter (“calcar ratio”). Results There were 26 of 168 (15.5%) patients with radiographic failures (19 related to fixation failure). Univariate analysis and multivariate analyses found quality of reduction (P Conclusions Quality of reduction, calcar distance, and calcar ratio independently correlated with fixation failure. This study provides optimal distances and ratios for calcar screw placement that can be used clinically.