Comparison of the fixation ability of headless compression screws and locking plate for metacarpal shaft transverse fracture.

ABSTRACT: Metacarpal shaft fractures are common hand fractures. Although bone plates possess strong fixation ability, they have several limitations. The use of headless compression screws for fracture repair has been reported, but their fixation ability has not been understood clearly.This study aimed to compare the fixation ability of locked plate with that of headless compression screw for metacarpal fracture repair.A total of 14 artificial metacarpal bones (Sawbones, Vashon, WA, USA) were subjected to transverse metacarpal shaft fractures and divided into 2 groups. The first group of bones was fixed using locked plates (LP group), whereas the second group was fixed using headless compression screws (HC group). A material testing machine was used to perform cantilever bending tests, whereby maximum fracture force and stiffness were measured. The fixation methods were compared by conducting a Mann-Whitney U test.The maximum fracture force of the HC group (285.6 ±â€Š57.3 N, median + interquartile range) was significantly higher than that of the LP group (227.8 ±â€Š37.5 N; P < .05). The median of the HC group was 25.4% greater. However, no significant difference in stiffness (P > .05) was observed between the HC (65.2 ±â€Š24.6 N/mm) and LP (61.7 ±â€Š19.7 N/mm) groups.Headless compression screws exhibited greater fixability than did locked plates, particularly in its resistance to maximum fracture force.

Finite Element Analysis of a Novel Anterior Locking Plate for Thoracolumbar Burst Fracture.

PURPOSE: The finite element analysis method was used to explore the biomechanical stability of a novel locking plate for thoracolumbar burst fracture fusion fixation. METHODS: The thoracolumbar CT imaging data from a normal volunteer was imported into finite software to build a normal model and three different simulated surgical models (the traditional double-segment fixation model A, the novel double-segment fixation model B, and the novel single-segment fixation model C). An axial pressure (500 N) and a torque (10 Nm) were exerted on the end plate of T12 to simulate activity of the spine. We recorded the range of motion (ROM) and the maximum stress value of the simulated cages and internal fixations. RESULTS: Model A has a larger ROM in all directions than model B (flexion 5.63%, extension 38.21%, left rotation 46.51%, right rotation 39.76%, left bending 9.45%, and right bending 11.45%). Model C also has a larger ROM in all directions than model B (flexion 555.63%, extension 51.42%, left rotation 56.98%, right rotation 55.42%, left bending 65.67%, and right bending 59.47%). The maximum stress of the cage in model A is smaller than that in model B except for the extension direction (flexion 96.81%, left rotation 175.96%, right rotation 265.73%, left bending 73.73%, and right bending 171.28%). The maximum stress value of the internal fixation in model A is greater than that in model B when models move in flexion (20.23%), extension (117.43%), and left rotation (21.34%). CONCLUSION: The novel locking plate has a smaller structure and better performance in biomechanical stability, which may be more compatible with minimally invasive spinal tubular technology.

Biomechanical Evaluation of Stand-Alone Oblique Lateral Lumbar Interbody Fusion Under 3 Different Bone Mineral Density Conditions: A Finite Element Analysis.

OBJECTIVE: To evaluate the biomechanical stability of stand-alone (SA) oblique lateral interbody fusion (OLIF) under different bone mineral density conditions. METHODS: The finite element model of L2-L5 was reconstructed and verified via computed tomography scan images (M0). The L4-L5 segment of SA OLIF was created based on the validation model. By changing bone mineral density, SA OLIF was established in the normal bone mineral density group (M1), osteopenia group (M2), and osteoporosis group (M3). A 500 N vertical axial preload was imposed on the superior surface of L2, and a 10 N-m moment was applied on the L2 superior surface along the radial direction to simulate 6 different physiological motions: flexion, extension, left and right lateral bending, left and right rotation. RESULTS: Compared with M0, the range of motion of the fusion segment was significantly reduced, and the maximum stress of the upper and lower end plates was significantly increased in all motion modes. Compared with M1, the maximum relative increases of range of motion, cephalic end-plate stress and tail end-plate stress of M2 in the L4-L5 segment were 39.1%, 9.9%, and 10.7%, and the maximum increases of the above parameters in M3 were 100%, 28.9%, and 31.6%. The maximum stress of the tail end plate of the M3 model during flexion was 54.617 MPa, which was very close to the yield stress of the lamellar bone (60 MPa). CONCLUSIONS: With the increase of the degree of osteoporosis, the maximum stress on the upper and lower end plates of the fusion segment increased significantly, thus increasing the potential risk of implant subsidence. SA OLIF could not provide sufficient stability for patients with osteoporosis.

Lateral migration resistance of screw is essential in evaluating bone screw stability of plate fixation.

Conventional evaluation of the stability of bone screws focuses on pullout strength, while neglecting lateral migration resistance. We measured pullout strength and lateral migration resistance of bone screws and determined how these characteristics relate to screw stability of locking plate (LP) and dynamic compression plate (DCP) fixation. Pullout strength and lateral migration resistance of individual bone screws with buttress, square, and triangular thread designs were evaluated in polyurethane foam blocks. The screw types with superior performance in each of these characteristics were selected. LP and DCP fixations were constructed using the selected screws and tested under cyclic craniocaudal and torsional loadings. Subsequently, the association between individual screws' biomechanical characteristics and fixation stability when applied to plates was established. Screws with triangular threads had superior pullout strength, while screws with square threads demonstrated the highest lateral migration resistance; they were selected for LP and DCP fixations. LPs with square-threaded screws required a larger force and more cycles to trigger the same amount of displacement under both craniocaudal and torsional loadings. Screws with triangular and square threads showed no difference in DCP fixation stability under craniocaudal loading. However, under torsional loading, DCP fixation with triangular-threaded screws demonstrated superior fixation stability. Lateral migration resistance is the primary contributor to locking screw fixation stability when applied to an LP in resisting both craniocaudal and torsional loading. For compression screws applied to a DCP, lateral migration resistance and pullout strength work together to resist craniocaudal loading, while pullout strength is the primary contributor to the ability to resist torsional loading.

Improving mandibular reconstruction by using topology optimization, patient specific design and additive manufacturing?-A biomechanical comparison against miniplates on human specimen.

In this study, topology optimized, patient specific osteosynthesis plates (TOPOS-implants) are evaluated for the mandibular reconstruction using fibula segments. These shape optimized implants are compared to a standard treatment with miniplates (thickness: 1.0 mm, titanium grade 4) in biomechanical testing using human cadaveric specimen. Mandible and fibula of 21 body donors were used. Geometrical models were created based on automated segmentation of CT-scans of all specimens. All reconstructions, including cutting guides for osteotomy as well as TOPOS-implants, were planned using a custom-made software tool. The TOPOS-implants were produced by electron beam melting (thickness: 1.0 mm, titanium grade 5). The fibula-reconstructed mandibles were tested in static and dynamic testing in a multi-axial test system, which can adapt to the donor anatomy and apply side-specific loads. Static testing was used to confirm mechanical similarity between the reconstruction groups. Force-controlled dynamic testing was performed with a sinusoidal loading between 60 and 240 N (reconstructed side: 30% reduction to consider resected muscles) at 5 Hz for up to 5 · 105 cycles. There was a significant difference between the groups for dynamic testing: All TOPOS-implants stayed intact during all cycles, while miniplate failure occurred after 26.4% of the planned loading (1.32 · 105 ± 1.46 · 105 cycles). Bone fracture occurred in both groups (miniplates: n = 3, TOPOS-implants: n = 2). A correlation between bone failure and cortical bone thickness in mandible angle as well as the number of bicortical screws used was demonstrated. For both groups no screw failure was detected. In conclusion, the topology optimized, patient specific implants showed superior fatigue properties compared to miniplates in mandibular reconstruction. Additionally, the patient specific shape comes with intrinsic guiding properties to support the reconstruction process during surgery. This demonstrates that the combination of additive manufacturing and topology optimization can be beneficial for future maxillofacial surgery.

Comparison of the Efficiency of Two Novel Guided Bone Regeneration Devices in the Rabbit Calvarial Model.

BACKGROUND: Creating a secluded large space using guided bone regeneration (GBR) is a novel osteogenesis technique used in the prevention of premature membrane exposure complications. However, this technique is not considered clinically feasible. OBJECTIVES: This study aimed to compare the outcome of the insertion of two novel GBR devices in a rabbit calvarial model in terms of mode of action, simplicity, and amount of new space and bone gained. MATERIALS AND METHODS: The expansible GBR (EGBR) device, composed mainly of a titanium plate, silicone membrane, and activation screw, was inserted beneath the periosteum in the calvarial area of eight rabbits. The smart GBR (SGBR) device, composed of silicone sheets and Nitinol strips, were inserted beneath the periosteum in the calvarial area of another 10 rabbits. Half of each group was sacrificed 2 months after surgery, and the other half was sacrificed after 4 months. RESULTS: Histological and microradiographical analysis showed that, at 2 months, the EGBR device achieved a mean space gain of 207.2 mm3, a mean bone volume of 68.2 mm3, and a mean maximum bone height of 1.9 mm. Values for the same parameters at 4 months were 202.1 mm3, 70.3 mm3, and 1.6 mm, respectively. The SGBR device had significantly higher (P < 0.05) mean space gain (238.2 mm3; 239.5 mm3), bone volume (112.9 mm3, 107.7 mm3), and bone height (2.7 mm; 2.6 mm) than the EGBR device at 2 and 4 months, respectively. CONCLUSION: Both devices proved to be effective in augmenting bone vertically through the application of GBR and soft tissue expansion processes. However, the SGBR device was more efficient in terms of mode of action, simplicity, and amount of bone created in the new space.

Fractured coracoid process with acromioclavicular joint dislocation: A case report.

RATIONALE: Coracoid processes (CPs) fracture with acromioclavicular (AC) joint dislocation are extremely rare. This combined injury has brought many challenges to surgeons, and the mechanism underlying the injury is still not fully understood. There is no clear consensus on its treatment. PATIENT CONCERNS: Here, we describe a CP fracture with AC joint dislocation in a middle-aged manual worker. DIAGNOSIS: Radiographs showed a fracture of the base of the CP and a third-degree AC joint separation. INTERVENTIONS: The patient was treated surgically with open reduction and internal fixation of the AC joint by LCP clavicle hook plate, and the CP was fixed with a 3.5 mm diameter cannulated screw. OUTCOMES: Three months after the operation, shoulder function was completely restored, and the affected shoulder had full mobility with no tenderness. Plain film radiography showed anatomical indications of the healing of these combined injuries. LESSONS: Although AC joint dislocation with CP fractures is extremely rare in adults, it is important to remind and remember that this possibility exists. In unclear cases, special radiographic films and CT are necessary. Surgical treatment of AC joint dislocation with CP fractures can provide solid stability and restore normal shoulder function with an excellent prognosis.

Distal third femoral shaft fractures in school-aged children: A comparative study of elastic stable intramedullary nail and external fixator.

Internal fixation such as elastic stable intramedullary(ESIN) nail and submuscular plate (SMP) is gaining popularity for femoral shaft fractures in school-aged children. However, external fixation (ExFix) might be a valuable option for the distal third femoral shaft fractures, where the fracture heals rapidly, but it is crucial to avoid angular malunion. This study aims to compare the clinical outcomes, postoperative complications of distal third femoral shaft fractures in school-aged children treated by ESIN versus ExFix.Patients aged 5 to 11 years with distal third femoral shaft fractures treated at our institute from January 2014 to January 2016 were included and categorized into ESIN (n = 33) and ExFix (n = 38) group. The preoperative data, including baseline information of the patients, radiographic parameters, and type of surgical procedure, were collected from the hospital database, and postoperative data, including complications, were collected during the follow-up visit.In all, 33 patients (average, 8.0 ±â€Š2.1 years, male 20, female 13) in the ESIN group and 38 patients (average, 8.3 ±â€Š2.3 years, male 23, female 15) in the ExFix group were included in this study. There was significantly less operative time for the ExFix group (45.4 ±â€Š7.8 min) as compared to the ESIN group (57.8 ±â€Š11.3 min) (P < .01), reduced estimated blood loss (EBL) in the ExFix group (9.9 ±â€Š3.5) as compared to the ESIN group (16.4 ±â€Š6.5) (P < .01). As for the frequency of fluoroscopy, there was a significant difference between the ExFix group (13.9 ±â€Š2.4) and the ESIN group (15.5 ±â€Š3.2) (P = .02). The rate of major complications was not significantly different between the 2 groups (P = .19). The rate of implant irritation was significantly higher in the ExFix group (28/38, 73.7%) than the ESIN group (12/33, 36.4%) (P < .01). The rate of surgical site infection (SSI) is significantly higher in the ExFix group (18/38, 47.4%)) than the ESIN group (1/33, 3%) (P < .01). The rate of scar concern was significantly higher in the ExFix (9/38, 23.7%) than the ESIN (2/33, 6.1%), (P = .04). According to the Flynn scoring system, 30(90.9%) patients in the ESIN group and 24(89.5%) patients in the ExFix group were rated as excellent. None of the patients had poor outcomes.Both ESIN and ExFix produced satisfactory outcomes in distal third femoral shaft fractures. ExFix remains a viable choice for selected cases, especially in resource-challenged and austere settings.

[Application of modified anterolateral supra-fibular-head approach in treatment of tibial plateau fractures involving posterolateral column].

OBJECTIVE: To explore effectiveness of reduction and internal fixation via modified anterolateral supra-fibular-head approach in treatment of tibial plateau fractures involving posterolateral column. METHODS: Between January 2016 and September 2018, 19 patients diagnosed as tibial plateau fractures involving posterolateral column were treated with reduction and internal fixation via modified anterolateral supra-fibular-head approach. There were 11 males and 8 females with an average age of 43.2 years (range, 28-65 years). The causes of tibial fracture were traffic accident (12 patients), falling injury (5 patients), and falling from height (2 patients). According to the Schatzker typing, the tibial fractures were rated as type Ⅱ in 9 cases, type Ⅲ in 4 cases, type Ⅴ in 4 cases, and type Ⅵ in 2 cases. The time from injury to operation was 5-13 days (mean, 8.5 days). There were 2 patients with osteoporosis. The operation time, intraoperative blood loss, and postoperative complications were recorded. The knee X-ray film was reviewed regularly to observe the fracture healing. At last follow-up, the fracture reductions were evaluated by Rasmussen radiological score. The knee joint function was evaluated by Hospital for Special Surgery (HSS) score system. RESULTS: The average operation time was 95 minutes (range, 65-130 minutes). The average intraoperative blood loss was 220 mL (range, 150-350 mL). All incisions healed by first intention. No complications such as infection or deep venous thrombosis occurred. All patients were followed up 12-20 months (mean, 15.4 months). X-ray films showed that the fractures healed with the healing time of 12-20 weeks (mean, 14.5 weeks). No complications such as loosening or breakage of internal fixation occurred. At last follow-up, according to the Rasmussen radiological score, the fracture reductions were evaluated as excellent in 13 cases, good in 4 cases, fair in 1 case, and poor in 1 case. HSS scores of knee joint function were excellent in 14 cases, good in 3 cases, fair in 1 case, and poor in 1 case. The knee joint range of motion was 90°-135°, with an average of 113.4°. CONCLUSION: Application of modified anterolateral supra-fibular-head approach in reduction and internal fixation for tibial plateau fractures involving posterolateral column has the advantages of full exposure, less trauma, safety, and reliable reduction and fixation.

Comparison of two reinforcement rings for primary total hip arthroplasty addressing displaced acetabular fractures: a biomechanical analysis.

INTRODUCTION: Aim of this study was to biomechanically compare two different acetabular cup fixation constructs in terms of fracture fixation for displaced acetabular fractures involving the anterior column with hemitransverse fracture under partial and full weight-bearing conditions. METHODS: Two different reinforcement rings designed as cages for primary THA were biomechanically tested in terms of managing a complex acetabular fracture. Single-leg stance cyclic loading was performed to assess fracture gap movement and fragment rotation. Twelve hemi pelvis Sawbones were divided into two groups: primary THA with acetabulum roof reinforcement plate (ARRP) (n = 6) and primary THA with Burch-Schneider reinforcement cage (BSRC) (n = 6). RESULTS: During loading under partial weight-bearing (250 N) fracture gap movement tended to be larger in the BSRC group as compared to the ARRP group. Under full weight-bearing conditions, the ARRP showed 60% significantly less motion (p = 0.035) of the os ilium to os ischii gap compared to BSRC. Fracture gap movements between the os ilium and spina iliaca fragments were significantly reduced by 76% (p = 0.048) for ARRP in contrast to BSRC. The ARRP group also demonstrated significantly less movement in the fracture gaps os ischii to quadrilateral plate (62% reduction, p = 0.009) and quadrilateral plate to spina iliaca (87% reduction, p < 0.001). Significantly less rotational movement of the quadrilateral plate to the os ilium was exhibited by the ARRP group (p = 0.015). CONCLUSIONS: The presented acetabulum roof-reinforcement plate (ARRP) provides stable conditions at the acetabular component with adequate stabilization of a displaced acetabular fracture.

Identification of the lateral femoral safe zone for drilling during LISS plate fixation of distal femur fractures.

BACKGROUND: The incidence of arterial injury associated with femoral fractures is approximately 1%. Lateral sub-muscular plate fixation is gaining popularity for the management of distal femoral fractures. The objective of this study was to assess the iatrogenic risk to the superficial femoral artery (SFA) during Less Invasive Stabilisation System (LISS) plate fixation of distal femoral fractures by analysing the range of distances and angles between LISS plate screws and the drilling line to the SFA. MATERIALS AND METHODS: We identified all patients who underwent LISS plate fixation of distal femoral fractures between 2008 and 2018 in our level-1 trauma centre. Patients who underwent postoperative computed tomography for any reason were eligible for inclusion in the study. Twenty-five patients met the inclusion criteria. The sample comprised 10 male and 15 female patients with a mean age of 55 years. The most common fracture type was a supracondylar femur fracture (56%), followed by an intercondylar fracture (36%). A 13-hole LISS plate was the most common plate length used (44%). A consultant radiologist reviewed all scans to verify the visibility and marking of the SFA. RESULTS: The median distance between the screw tip and the SFA was 21 mm (range, 8-65 mm). There was a negative correlation between the LISS plate hole number and the trajectory of drilling (Pearson coefficient: -0.87, p < 0.001). Using a linear regression model, the SFA was more likely to be in the line of drilling when the 6th to 10th holes in the LISS plate were used. CONCLUSION: Extra care is needed when drilling into the LISS plate holes from the lateral to the medial direction in order to reduce the risk of iatrogenic injury to the SFA, especially in the high-risk plate zone where the artery can be close to the drilling line.

Comparison of the efficacy of a distal clavicular locking plate with and without a suture anchor in the treatment of Neer IIb distal clavicle fractures.

BACKGROUND: To compare the clinical outcomes between the use of a distal clavicular locking plate alone and the combined use of a plate and a coracoclavicular suture anchor in the treatment of Neer IIb distal clavicle fractures and to discuss the application procedure of suture anchors. METHODS: This is a retrospective study. Thirty-four patients with unilateral Neer IIb distal clavicle fractures who underwent open reduction and internal fixation with a distal clavicular locking plate only (16 patients) or with both a plate and a coracoclavicular suture anchor (18 patients) were evaluated. The main observation data included the Constant-Murley Shoulder Function Score (CMS), rate of postoperative complications, and union time. RESULTS: The distal clavicular locking plate and coracoclavicular suture anchor combination group had better outcomes in the Constant-Murley score (94.6 ± 4.5 vs. 90.1 ± 9.5) (P < 0.05) and a shorter union time (13.9 ± 2.3 vs. 16.1 ± 3.0) (P < 0.05) than the locking plate only group did, and the rate of complications showed no significant difference, 16.7% vs. 31.2% (5/16) (P>0.05). CONCLUSIONS: Both methods achieved good results in the treatment of Neer IIb distal clavicle fractures; however, the use of both locking plates and coracoclavicular suture anchors can provide more stability in the early stage after operation than can the use of locking plates alone, which can make the sped of union quicker and result in better clinical outcomes. For elderly patients with comminuted Neer IIb distal clavicle fractures, a locking plate combined with a suture anchor is recommended to provide more stability in the early stage after the operation.

[Early effectiveness of mini-Swashbuckler approach for distal femoral type C fractures].

OBJECTIVE: To explore the early effectiveness and advantages of mini-Swashbuckler approach in treatment of distal femoral type C fractures by comparing with Swashbuckler approach. METHODS: A retrospective analysis was made on 43 patients with distal femoral type C fractures between January 2014 and June 2018. Twenty-two patients were treated with open reduction via mini-Swashbuckler approach and internal fixation with less invasive stabilization system (LISS) plate in modified group; and 21 patients were treated with open reduction via Swashbuckler approach and internal fixation with LISS plate in traditional group. There was no significant difference in age, gender, cause of trauma, fracture classification, fracture side, interval between injury and operation, and complications between the two groups ( P>0.05). The operation time, intraoperative blood loss, intraoperative fluoroscopy times, hospitalization time, fracture healing time, Hospital for Special Surgery (HSS) scores of the knee, and postoperative complications were recorded and compared between the two groups. RESULTS: The operation successfully completed in both groups. The operation time of the modified group was significantly longer than that of the traditional group, the fluoroscopy times was increased and the blood loss was reduced, the differences were significant ( P<0.05). There was no significant difference in hospitalization time between the two groups ( t=0.277, P=0.783). All patients in the two groups were followed up 6-8 months, with an average of 7.2 months. Fractures healed in both groups, there was no significant difference in healing time between the two groups ( t=0.861, P=0.394). The HSS scores of the modified group were 82.91±2.88 and 89.28±3.63 at 3 and 6 months after operation, respectively, which were superior to those of the traditional group (74.62±3.64) and (81.48±4.55) ( t=8.306, P=0.000; t=6.231, P=0.000). There was 1 case of incision infection, 1 case of deep vein thrombosis, and 2 cases of knee flexion and extension dysfunction in traditional group, and 1 case of deep vein thrombosis, 1 case of varus deformity, and 1 case of internal fixation loosening in modified group. There was no significant difference in the incidences of complications between the two groups ( P>0.05). CONCLUSION: Compared with Swashbuckler approach, mini-Swashbuckler approach has limited visual field exposure, which leads to prolonged operation time and increased fluoroscopy times, but the risks of complications do not increase. Because of its small soft tissue injury and less blood loss, it is conducive to the recovery of knee joint function after operation.

Volar locking plate versus external fixation with optional additional K-wire for treatment of AO type C2/C3 fractures: a retrospective comparative study.

PURPOSE: This study aimed to compare the radiographic and functional results of Arbeitsgemeinschaftfür Osteosynthesefragen (AO) type C2/C3 fracture of distal radius between volar locking plate (VLP) and external fixation (EF). METHODS: It was a retrospective comparative study. Between January 2015 and March 2018, a total of 62/117 patients who underwent EF (23) or VLP fixation (39) for AO type C2/C3 distal radius fractures were assessed. The follow-up period was at least 12 months. Gartland-Werley scale and the disabilities of the arm, shoulder, and hand (DASH) scale were used to evaluate the overall functional outcomes; wrist range of motion and grip strength were measured. The radiographic parameters included radial inclination, volar tilt, radial length, ulnar variance, and articular step-off. All of the comparisons were performed using SPSS 21.0. RESULTS: The mean follow-up time was 17.1 months. At final visit, VLP performed better in wrist flexion (69.7° vs 62.3°, p < 0.001), forearm pronation (73.1° vs 64.8°, p = 0.027) and supination (70.6° vs 63.1°, p = 0.033) than EF, but not different with regard to other kinematic parameters. No significant difference was found between two groups, in term of Gartland-Werley or DASH score (p > 0.05). The ulnar variance and articular step-off was significantly more improved in VLP than EF group, being 0.6 vs 1.6 mm (p = 0.002) and 0.5 vs 1.2 mm (p = 0.007). The overall rate of complications did not differ in both groups (28.2% vs 34.5%) (p = 0.587). CONCLUSIONS: Compared to EF, VLP fixation showed better performance in wrist mobility, correction of ulnar variance, and improving articular congruence, but with the comparable overall functional outcomes and complication rate.

Examining implant superiority in the treatment of simple pertrochanteric fractures of the proximal femur in elderly patients.

BACKGROUND: The aim of this study was to compare the clinical and radiological results of the proximal femoral nail antirotation (PFNA) with those of the dynamic hip screw (DHS) and percutaneous compression plate (PCCP) in the treatment of simple pertrochanteric fractures. METHODS: A total of 203 patients were included in the study. PFNA fixations were performed in 73 patients (PFNA group), DHS in 68 patients (DHS group), and PCCP in 62 patients (PCCP group). The main outcome measurements were perioperative properties, the Harris hip score, changes in the neck-shaft angle, and loss of the abductor muscle strength. Data were compared between the groups. RESULTS: The mean estimated total blood loss and the number of patients receiving the blood transfusion rate in the PFNA group were statistically significantly lower. The mean operation and fluoroscopy times in the PCCP group were statistically significantly higher. The mean loss of the abductor muscle strength and changes in the neck-shaft angle in the PFNA group were statistically significantly higher. The mean Harris hip scores were similar. CONCLUSION: Our findings demonstrated that although PFNA was superior with regard to the perioperative data, DHS and PCCP were superior in maintaining the reduction and the abductor muscle strenght. All three implants were similar and had satisfactory functional outcomes.

Preliminary exploration of a quantitative assessment index for the matching performance of anatomical bone plates using computer.

BACKGROUND: To explore a new quantitative index to assess the matching performance of anatomical bone plates using digital technology. METHODS: CT data of normal tibias of 40 adults were collected. Two brands of medial distal tibia plates were digitized. Two trained orthopedists simulated the surgical operation in Rhino 5.1 software by placing the plate curve on the medial distal tibia surface. The volume of the interstice between the plate curve and the bone surface was measured. The inverse value of this average interstice distance was used as the matching performance index (MPI). A wall thickness analysis tool was used to mark various interstice distances with varied colors. RESULTS: The Kangli medial distal tibia plate had a MPI of 0.55 ± 0.08 by operator A and 0.55 ± 0.06 by operator B. The general care medial distal tibia plate had a MPI of 0.32 ± 0.06 by operator A and 0.31 ± 0.05 by operator B. There were significant variations in the MPI between the two types of plates by both operators (p < 0.001). And significant variations were observed in the MPI of general care medial distal tibia plates among various operator groups (p = 0.028). CONCLUSION: This quantitative index of matching performance is straightforward and intuitive. However, we still need a method to improve the experimental repeatability, especially when it comes to a plate with poor matching performance.

Accuracy and precision of measurements performed on three-dimensional printed pelvises when compared to computed tomography measurements.

The preoperative contouring of plates decreases the duration of surgery and improves the quality of the reduction of pelvic fractures. Patient-tailored three-dimensionally printed pelvises might be an interesting tool for achieving that purpose. Currently, no study has evaluated the accuracy of measurements performed on three-dimensional printed models in comparison with computed tomography data for complex bones, such as the pelvis. This study examined whether the measurements obtained on pelvises printed using dual-material fused deposition modeling technology are not significantly different from those obtained on computed tomography images. The computed tomography images of the pelvic region from 10 dogs were used to produce three-dimensionally printed models with a dual-material fused deposition-modeling process. Four segments were measured on both three-dimensionally printed models and computed tomography images. The measurements were performed by three observers and repeated twice. Concordance correlation coefficients were used to assess the precision and accuracy of the measurements as well as evaluate the agreement between the methods. The accuracy of measurements between the methods was > 0.99 for all measurements. The precision was almost perfect for AE (0.996), substantial for BD and BC (0.963 and 0.958, respectively), and moderate for CD (0.912). These results indicate that, despite some minor variations, the measurements performed on printed models reproduced the computed tomography data reliably.

Ex Vivo Biomechanical Comparison of Titanium Locking Plate, Stainless Steel Nonlocking Plate, and Tie-in External Fixator Applied by a Dorsal Approach on Ostectomized Humeri of Pigeons (Columba livia).

To compare the bending strength of a locking plate (LP), nonlocking plate (NLP), and an external skeletal fixator intramedullary pin (ESF-IM) tie-in fixation applied by a dorsal approach in an avian humerus fracture model, 5 left humeri obtained from pigeon (Columba livia) cadavers were randomly assigned to each repair technique (n = 15). The ESF-IM group was repaired with a 0.062-inch intramedullary pin tied-in with two 0.035-inch positive profile transfixation pins using acrylic filled plastic tubing. The LP group was repaired with a dorsally applied titanium 1.6-mm screw 7-hole locking plate (1 bicortical and 2 monocortical screws in each segment). The NLP group was repaired with a dorsally applied 6-hole stainless steel 1.5-mm dynamic compression plate (all bicortical screws). All constructs were applied before complete ostectomy to allow perfect reconstruction. Constructs were cyclically tested nondestructively for 1000 cycles in four-point bending before being tested to failure. Outcome measures included stiffness, strength, and strain energy. All specimens cycled without failure. The ESF-IM specimens were significantly stiffer and stronger than the plated repair groups. Plated constructs had significantly higher strain energies than ESF-IM. LP and NLP were of equal stiffness, strength, and strain energies. This study demonstrated that bending biomechanical properties of the ESF-IM configuration were superior to those of the dorsal plate fixation. Exact properties of fixation required to facilitate avian fracture healing are largely unknown. Further study, including assessments of optimal plate position and configuration, and torsional and in vivo studies in avian species are warranted.

Locked Plating and Advanced Augmentation Techniques in Osteoporotic Fractures.

"The incidence of osteoporotic fracture is increasing with the aging US population. Because osteoporosis leads to a decrease in bone mineral density with a decrease in both trabecular and cortical bones, osteoporotic fracture presents fixation challenges with standard plate and screw constructs. Locked plating has been developed to create a fixed-angle plate-screw construct that is more resistant to failure in osteoporotic bone. Endosteal replacement, additional plates, and cement augmentation have all been demonstrated to further supplement osteoporotic fracture fixation. Technologies on the horizon to treat osteoporotic fracture include SMV screws, hydroxyapatite-coated implants, and far cortical locking screws."

Wrist Fractures and Osteoporosis.

Distal radial fractures account for up to 18% of all fractures in patients over 65 years of age, and osteoporosis is a predominant factor in these fractures. Fracture treatment may include closed reduction and casting/splinting, external fixation, and open reduction and internal fixation.