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PURPOSE: To identify characteristics associated with loss of reduction following open reduction and locked plate fixation (ORIF) of proximal humerus fractures in older adults and determine if loss of reduction affects patient reported outcomes (PROs), range of motion (ROM), and complication rates during the first postoperative year. METHODS: Patients >55 years old who underwent proximal humerus ORIF were reviewed. Patient and fracture characteristics were recorded. Fixation characteristics were measured on the initial postoperative AP radiograph including humeral head height (HHH) relative to the greater tuberosity (GT), head shaft angle (HSA), screw-calcar distance, and screw tip-joint surface distance. Loss of reduction was defined as GT displacement >5 mm or HSA displacement >10° on final follow up radiographs. Patient, fracture, and fixation characteristics were tested for association with loss of reduction. Outcomes including ROM, visual analog scale pain and PROMIS scores, and complication/reoperation rates during the first postoperative year were compared between those with or without loss of reduction. RESULTS: A total of 79 patients were identified, 23 (29.1%) of which had a loss of reduction. Calcar comminution (relative risk [RR]=2.5, 95% Confidence Interval [CI]=1.3-5.0, p<0.01), HHH <5 mm above GT (RR=2.0, CI=1.0-3.9, p = 0.048), and screw-calcar distance ≥12 mm (RR=2.1, CI=1.1-4.1, p = 0.03) were risk factors for loss of reduction. Upon multivariate analysis, calcar comminution was determined to be an independent risk factor for loss of reduction (RR=2.4, CI=1.2-4.7, p = 0.01). Loss of reduction led to higher complication (44% vs 13%, p<0.01) and reoperation rates (30% vs 7%, p<0.01), and decreased achievement of satisfactory ROM (>90° active forward flexion, 57% vs 82%, p = 0.02) compared to maintained reduction, but similar PROs. CONCLUSIONS: Calcar comminution, decreased HHH, and increased screw-calcar distance are risk factors for loss of reduction following ORIF of proximal humerus fractures. These morphologic and technical factors are important considerations for prolonged reduction maintenance.

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Objective:To investigate the effect of the use of medial calcar screws on the treatment of Neer type Ⅲ proximal humeral fracture with Multiloc intramedullary nailing.Methods:A retrospective study was conducted to analyze the data of 36 patients with Near type Ⅲ fracture of the proximal humerus who had received Multiloc intramedullary nailing at Department of Upper Limbs, Sichuan Orthopedic Hospital from January 2016 to December 2021. There were 6 males and 30 females with an age of (63.9±5.3) years. They were divided into 2 groups according to whether medial calcar screws had been used or not. There were 17 cases in the group without medial calcar screws and 19 cases in the group with medial calcar screws. The 2 groups were compared in terms of flexion and lifting, external rotation, internal rotation and back touch, visual analogue scale (VAS), American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score for shoulder function (Constant score), neck shaft angle, and incidence of complications at the last follow-up.Results:There were no statistically significant significances in the preoperative general data between the 2 groups, indicating comparability between the groups ( P>0.05). The 36 patients were followed up for 13.5(12.0,19.8) months after surgery. The flexion and lifting, external rotation, internal rotation and back touch, VAS, ASES score, Constant score, neck shaft angle at the last follow-up in the group without medial calcar screws were, respectively, 134.1°±8.4°, 32.1°±5.3°, 14.0 (13.0, 15.5) , 0.0 (0.0, 1.0), 78.2±5.2, 78.0±5.8, and 137.6°±8.1°, insignificantly different from those in the group with medial calcar screws [134.7°±6.1°, 35.0(30.0, 35.0)°, 14.0(13.0, 15.0), 1.0 (0.0, 1.0), 78.2±5.4, 76.7±4.5, and 136.9°±6.4°] ( P>0.05). Postoperative complications occurred in 6 patients in each group, showing no statistically significant difference between the 2 groups ( P=1.000). Conclusion:The use of medial calcar screws has no significant impact on the postoperative shoulder function and incidence of complications in the treatment of Neer type Ⅲ fractures of the proximal humerus with Multiloc intramedullary nailing.

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BACKGROUND: Endosteal augmentation enhances the stability of osteoporotic proximal humeral fracture fixation, but the optimal configuration is unknown. The purpose of this study was to compare the biomechanical properties of different lengths of fibula with or without calcar screw in osteoporotic proximal humeral fracture. METHODS: Three-part proximal humeral fractures with osteopenia were created on 20 pairs of fresh-frozen humeri specimens and allocated to four groups: (1) locking plate with a 6-cm fibular strut allograft, (2) locking plate with a 6-cm fibular strut allograft and additional calcar screws, (3) locking plate with a 12-cm fibular strut allograft，and (4) locking plate with a 12-cm fibular strut allograft and additional calcar screws. Specimens were loaded to simulate the force at 25° abduction. Thereafter, an axial stiffness test and a compound cyclic load to failure test were applied. Structural stiffness, number of cycles loaded to failure and relative displacement values for 5000 cycles at predetermined measurement points were recorded using a testing machine and a synchronized 3D video tracking system. FINDINGS: In terms of initial stiffness, number of cycles loaded to failure, and relative displacement values, the groups with 12-cm fibular strut showed obvious improvement compared to the groups with 6-cm fibular strut irrespective of the influence of calcar screw implementation. Further, the groups implemented with calcar screws also showed promising biomechanical stability irrespective of fibular length. INTERPRETATION: Lateral locking plate with longer endosteal fibular augmentation and calcar screw can significantly improve biomechanical stability for elderly proximal humeral fractures with posteromedial comminution.

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OBJECTIVE: The purpose of this study was to evaluate the best placement of calcar screws in proximal humerus fracture surgeries. METHODS: This retrospective cohort study included clinical and radiographic outcomes of 98 patients treated with proximal humerus fracture surgeries between January 2017 and June 2020. Demographic data of patients were obtained from medical records. The surgical and radiographic results were also collected: operation time, blood loss, time to surgery, fibular allograft, disruption of medial region hinge, Neer classification, and recovery of medial support. Patients were allocated into two groups: the locking plate group (n = 65) and the intramedullary nail group (n = 33). In this study, we proposed new predictive indicators, named horizontal ratio (HR) and vertical ratio (VR), to quantify the placement of calcar screws in these two groups. A receiver operating characteristic (ROC) analysis was conducted to display the accuracy of these indicators. Shoulder activity, visual scale analog (VAS) score, and Constant score were performed to evaluate postoperative clinical outcomes at 1 year follow-up. RESULTS: In the multivariate logistic regression analysis, only time to surgery and effective medial support were considered statistically significant factors of postoperative complications (p < 0.05). Significant differences were observed between medial support and postoperative complications both in the locking plate group and the intramedullary nail group (p < 0.05). Only the vertical ratio of locking plate (VRLP) was a statistically significant predictor of postoperative complications (p < 0.05). The area under curve was calculated to assess the predictive value of VRLP, which came to 0.84. In addition, a ROC analysis found quantifiable thresholds of the VR was 0.1713 as measures to avoid postoperative complications in the locking plate fixation. CONCLUSION: In locking plate fixation, the incidence of postoperative complications increased significantly when the VR of calcar screws greater than 0.1713, which was beneficial to surgeons to place calcar screws.

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Objective: To explore the biomechanical stability of the medial column reconstructed with the exo-cortical placement of humeral calcar screw by three-dimensional finite element analysis. Methods: A 70-year-old female volunteer was selected for CT scan of the proximal humerus, and a wedge osteotomy was performed 5 mm medially inferior to the humeral head to form a three-dimensional finite element model of a 5 mm defect in the medial cortex. Then, the proximal humeral locking plate (PHILOS) was placed. According to distribution of 2 calcar screws, the study were divided into 3 groups: group A, in which 2 calcar screws were inserted into the lower quadrant of the humeral head in the normal direction for supporting the humeral head; group B, in which 1 calcar screw was inserted outside the cortex below the humeral head, and the other was inserted into the humeral head in the normal direction; group C, in which 2 calcar screws were inserted outside the cortex below the humeral head. The models were loaded with axial, shear, and rotational loadings, and the biomechanical stability of the 3 groups was compared by evaluating the peak von mises stress (PVMS) of the proximal humerus and the internal fixator, proximal humeral displacement, neck-shaft angle changes, and the rotational stability of the proximal humerus. Seven cases of proximal humeral fractures with comminuted medial cortex were retrospectively analyzed between January 2017 and December 2020. Locking proximal humeral plate surgery was performed, and one (5 cases) or two (2 cases) calcar screws were inserted into the inferior cortex of the humeral head during the operation, and the effectiveness was observed. Results: Under axial and shear force, the PVMS of the proximal humerus in group B and group C was greater than that in group A, the PVMS of the internal fixator in group B and group C was less than that in group A, while the PVMS of the proximal humerus and internal fixator between group B and group C were similar. The displacement of the proximal humerus and the neck-shaft angle change among the 3 groups were similar under axial and shear force, respectively. Under the rotational torque, compared with group A, the rotation angle of humerus in group B and group C increased slightly, and the rotation stability decreased slightly. All the 7 patients were followed up 6-12 months. All the fractures healed, and the healing time was 8-14 weeks, with an average of 10.9 weeks; the neck-shaft angle changes (the difference between the last follow-up and the immediate postoperative neck-shaft angle) was (1.30±0.42)°, and the Constant score of shoulder joint function was 87.4±4.2; there was no complication such as humeral head varus collapse and screw penetrating the articular surface. Conclusion: For proximal humeral fractures with comminuted medial cortex, exo-cortical placement of 1 or 2 humeral calcar screw of the locking plate outside the inferior cortex of the humeral head can also effectively reconstruct medial column stability, providing an alternative approach for clinical practice.

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INTRODUCTION: Traditionally, femoral neck fracture fixation has been performed using three partially threaded cancellous screws. However, fracture collapse with femoral neck shortening, and varus deformation frequently occurs due to posterior medial comminution and lack of calcar support. We hypothesize replacing the inferior neck/calcar screw with a fully threaded, length stable, screw will provide improved biomechanical stability, decrease femoral neck shortening and varus collapse. METHODS: Ten matched cadaveric pairs (20 femurs) were randomly assigned to two screw fixation groups. Group 1 (Hybrid) utilized one fully threaded calcar screw & two partially threaded superior screws. Group 2 (PT) utilized all partially threaded screws. Specimens underwent standardized femoral neck osteotomies, 45° from the horizontal, with 5 mm posteromedial wedge removed to simulate posteromedial comminution. Screws were placed using fluoroscopic guidance. Specimens were biomechanically tested using two loading sequences: 1) Axial load applied up to 700 N, followed by cyclic loading at 2 Hz with loads of 700 to 1,400 N for 10,000 cycles. 2) All surviving constructs were cyclically loaded to failure in stepwise incremental manner with max load of 4,000 N. Paired t-tests used to compare stiffness, cycles to failure, and max load to failure (defined as 15 mm load actuator displacement). RESULTS: Construct stiffness was 2848 ± 344 N/mm in PT vs. 2767 ± 665 for Hybrid (P = 0.628). Load to failure demonstrated, hybrid superiority with max cycles to failure (3797 ± 400 cycles) vs. (2981 ± 856 cycles in PT) (p = 0.010), and max load prior to failure (3290 ± 196 N) vs. (2891 ± 421 N in PT) (p = 0.010). No significant difference in bone mineral density was noted in any of the specimens. CONCLUSIONS: Our study is the first to assess the biomechanical effects of hybrid fixation for femoral neck fractures. Hybrid screw configuration resulted in significantly stronger constructs, with higher axial load and increased cycles prior to failure. The advantageous mechanical properties demonstrated using a fully threaded inferior calcar screw provides a length stable construct which may prevent the common complication of excessive femoral neck shortening, varus collapse and poor functional outcome.

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BACKGROUND: Proximal humeral fracture is the third most common of osteoporotic fracture. Most surgical cases were treated by fixation with anatomical locking plate system. The calcar screw plays a role in medial support and improving varus stability. Proximal humerus fracture in elderly patients are commonly seen with greater tuberosity (GT) fracture. The GT fragment is sometimes difficult to use as an anatomic landmark for proper plate and screw position. Therefore, the insertion of pectoralis major tendon (PMT) may be used as an alternative landmark for appropriate plate and calcar screw position. The purpose of study is going to identify the vertical distance from PMT to a definite point on the position of locking plate. METHODS: 30 cadaveric shoulders at the department of clinical anatomy were performed. Shoulders with osteoarthritic change (n = 5) were excluded. Finally, 25 soft cadaveric shoulders were recruited in this study. The PHILOS™ plate was placed 2 mm posterior to the bicipital groove. A humeral head (HH) was cut in the coronal plane at the level of the anterior border of the PHILOS plate with a saw. A calcar screw was inserted close to the inferior cortex of HH. Distance from the upper border of elongated combi-hole (UB-ECH) to the upper border of pectoralis major tendon (UB-PMT) was measured. The plate was then moved superiorly until the calcar screw was 12 mm superior to the inferior border of HH and the distance was repeatedly measured. RESULTS: The range of distance from UB-PMT to the UB-ECH was from - 4.50 ± 7.95 mm to 6.62 ± 7.53 mm, when calcar screw was close to inferior border of HH and when the calcar screw was 12 mm superior to the inferior border of HH, respectively. The highest probability of calcar screw in proper location was 72% when UB-ECH was 3 mm above UB-PMT. DISCUSSION AND CONCLUSION: The GT fragment is sometimes difficult to use as an anatomic landmark for proper plate and screw position. PMT can be used as an alternative anatomic reference. UB-PMT can serve as a guide for proper calcar screw insertion. UB-ECH should be 3 mm above UB-PMT and three-fourths of cases achieved proper calcar screw location.

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BACKGROUND: Achieving medial support for proximal humeral fractures (PHFs) by regular calcar screw positioning is challenging when the humeral head is small or locking plates are placed distally, as there are unable inserted calcar screws into the humeral head. We aimed to investigate the suitability of the 2 strategies, slotting calcar screw (SCS) and off-axis calcar screw (OCS), to achieve medial support for PHFs. METHODS: Regular calcar screw (RCS), SCS, OCS, and noncalcar screw (NCS) were tested via mechanical experiments and finite element analysis (FEA), using synthetic bones for biomechanical comparisons. All PHFs treated in our hospital from March 2017 to March 2019 were reviewed. The patients were divided into 3 groups based on the calcar screw fixation: RCS, SCS, and OCS. The postoperative varus collapse (neck-shaft angle changed to less than 120°) and Disabilities of the Arm, Shoulder and Hand (DASH) scores were recorded. RESULTS: The properties of RCS, SCS, and OCS against the torsion and varus force were superior to those of NCS, whereas the stiffness of SCS, OCS, and RCS were similar. FEA predicted lower peri-screw strains in the OCS and SCS than in the RCS, indicating a lower risk of cut-out. Patients (n = 125; 75 female, 50 male) aged 55.9 ± 13.0 years were evaluated. Compared with the RCS (5/55), varus collapse incidences were not significantly higher following SCS (0/29, P = .094) or OCS (3/41, P = .756), and neither were DASH scores (P = .867 and .736, respectively). CONCLUSIONS: This study is a preliminary study demonstrating that the SCS and OCS fixation strategies could be useful alternatives when regular calcar fixation is not possible using the plate at hand.

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AIMS: The aim of this study was to explore why some calcar screws are malpositioned when a proximal humeral fracture is treated by internal fixation with a locking plate, and to identify risk factors for this phenomenon. Some suggestions can be made of ways to avoid this error. METHODS: We retrospectively identified all proximal humeral fractures treated in our institution between October 2016 and October 2018 using the hospital information system. The patients' medical and radiological data were collected, and we divided potential risk factors into two groups: preoperative factors and intraoperative factors. Preoperative factors included age, sex, height, weight, body mass index, proximal humeral bone mineral density, type of fracture, the condition of the medial hinge, and medial metaphyseal head extension. Intraoperative factors included the grade of surgeon, neck-shaft angle after reduction, humeral head height, restoration of medial support, and quality of reduction. Adjusted binary logistic regression and multivariate logistic regression models were used to identify pre- and intraoperative risk factors. Area under the curve (AUC) analysis was used to evaluate the discriminative ability of the multivariable model. RESULTS: Data from 203 patients (63 males and 140 females) with a mean age of 62 years (22 to 89) were analyzed. In 49 fractures, the calcar screw was considered to be malpositioned; in 154 it was in the optimal position. The rate of malpositioning was therefore 24% (49/203). No preoperative risk factor was found for malpositioning of the calcar screws. Only the neck-shaft angle was found to be related to the risk of screw malpositioning in a multivariate model (with an AUC of 0.72). For the fractures in which the neck-shaft angle was reduced to between 130° and 150°, 91% (133/46) of calcar screws were in the optimal position. CONCLUSION: The neck-shaft angle is the key factor for the appropriate positioning of calcar screws when treating a proximal humeral fracture with a locking plate. We recommend reducing the angle to between 130° and 150°. Cite this article: Bone Joint J 2020;102-B(12):1629-1635.

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OBJECTIVE: The purpose of this study is to analyze the radiological and functional outcome of complex proximal humerus fractures treated by open reduction and plate fixation, and how radiological parameters correlate with functional outcome. DESIGN: Retrospective study. SETTING: Level-1 trauma center. PATIENTS/METHODS: One hundred twenty-seven patients were analyzed, with a mean follow-up of 5 (3-7) years. OUTCOME MEASUREMENTS: Radiological parameters studied were neck-shaft angle (NSA), greater tuberosity (GT) to articular surface (AS) distance, medial hinge reduction, and presence (or absence) of calcar screw. Functional outcome evaluated by DASH and Constant-Murley (C-M) score. RESULTS: The mean age is 53.8 years. All patients had a union in 14 (12-18) weeks. The mean NSA is 135° (112-155°). One hundred and thirteen patients with an NSA of >120° had a good functional outcome. Fourteen patients with NSA ≤120° had shoulder abduction <90°. The mean GT to AS distance is 7.2 mm (-2 to 16). The superior displacement of GT above AS is associated with abduction of <90° (16 patients). The mean medial gap is 3 mm (0-17). In 14 patients with a medial gap of >4 mm and without calcar screw, varus collapse is observed. All patients had a good outcome on DASH score and 122 patients had good to excellent outcome on C-M score. Five patients with poor outcome on C-M score had NSA <120° and displacement of GT above AS. CONCLUSION: Radiographic indicators for poor outcome are varus angulation with NSA <120°, superior displacement of GT above AS, the presence of medial gap >4 mm, and absence of calcar specific screw. This "terrible triad" of proximal humerus fracture should be avoided during operative fixation.

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BACKGROUND: This study aimed to explore the effect of retaining inferomedial cortical bone contact and fixation with calcar screws on the dynamic and static mechanical stability of proximal humerus fractures treated with a locking plate. METHODS: Twelve Synbone prosthetic humeri (SYNBONE-AG, Switzerland) were used for a wedge osteotomy model at the proximal humerus, in four groups. In the cortex contact + screw fixation group and cortex contact group, the inferomedial cortical bone contact was retained. In the screw fixation group and control group, the inferomedial cortical bone contact was not retained. Calcar screw fixation was implemented only in the screw fixation groups. The dynamic and static mechanical stability of the models were tested with dynamic fatigue mechanics testing, quasi-static axial compression, three-point bending, and torsion testing. RESULTS: The cortex contact + screw fixation group showed the longest fatigue life and the best stability. There was 35% difference in fatigue life between the cortex contact + screw fixation group and the cortex contact group, 43%between the cortex contact + screw fixation group and screw fixation group, and 63% between the cortex contact + screw fixation group and screw fixation group (P < 0.01). The cortex contact + screw fixation group showed the best axial compressive stiffness, bending stiffness, and torsion stiffness; these were successively decreased in the other three groups (P < 0.01). CONCLUSION: Retaining inferomedial cortical bone contact and fixation with two calcar screws maintained fracture stability with the highest strength and minimum deformation. Of the two methods, restoration of the inferomedial cortical bone support showed better dynamic and static biomechanical properties than placement of calcar screws alone.

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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 < .001), calcar distance (P < .001), and calcar ratio (P < .001) to be significantly associated with radiographic success. In all patients, receiver operating characteristic analysis found quantifiable thresholds of 12 mm or within the bottom 25% of the humeral head as measures to prevent fixation failure. 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.

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BACKGROUND: The objective of this study was to evaluate the biomechanical effect of an additional unlocked calcar screw compared to a standard setting with three proximal humeral head screws alone for fixation of an unstable 2-part fracture of the surgical neck. HYPOTHESIS: The additional calcar screw improves stiffness and failure load. METHODS: Fourteen fresh frozen humeri were randomized into two equal sized groups. An unstable 2-part fracture of the surgical neck was simulated and all specimens were fixed with the MultiLoc(®)-nail. Group I represented a basic screw setup, with three locked head screws and two unlocked shaft screws. Group II was identical with a supplemental unlocked calcar screw (CS). Stiffness tests were performed in torsional loading, as well as in axial and in 20° abduction/20° adduction modes. Subsequently cyclic loading and load-to-failure tests were performed. Resulting stiffness, displacement under cyclic load and ultimate load were compared between groups using the t-test for independent variables (α=0.05). RESULTS: No significant differences were observed between the groups in any of the biomechanical parameters. Backing out of the CS was observed in three cases. DISCUSSION: The use of an additional unlocked calcar screw does not provide mechanical benefit in locked nailing of an unstable 2-part fracture of the surgical neck.

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BACKGROUND: The objective of this study was to investigate the biomechanical effects of medial fracture gap augmentation in locked plating of an unstable 2-part proximal humeral fracture with calcar screws and insertion of a corticocancellous bone block. Furthermore the mechanical behavior of dynamic locking screws in the non-parallel arrangement of a proximal humeral plate was of interest. METHODS: Thirty-two fresh frozen humeri were randomized in four equal groups. An unstable 2-part fracture was fixed by locked plating in all specimens. The basic screw setup was supplemented by additional calcar screws in one group. Humeral head screws were replaced by dynamic locking screws in a second group. The third group featured an additional corticocancellous femoral head allograft. Assessment of stiffness was followed by cyclic loading and load to failure tests. Resulting stiffness, fracture gap deflection and ultimate load were compared utilizing Bonferroni corrected t-test for independent samples. FINDINGS: The mechanical effect of additional calcar screws was non-significant as compared to the basic screw configuration whereas bone block insertion significantly increased construct stiffness and failure load. The use of dynamic locking screws did not significantly reduce construct stiffness when compared to conventional locking screws. INTERPRETATION: Additional calcar screws alone did not improve the initial biomechanical properties of an unstable 2-part proximal humeral fracture model. However bone block augmentation appeared to be a reliable alternative of additional bony support by raising stiffness and failure load. Dynamic locking screws did not show their expected dynamic component when used in a non-parallel arrangement.

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