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Acetabular fracture surgery follows the primary aim of anatomic reduction and rigid stable fixation of the fracture. Infraacetabular screws (IAS) allow for an increased stability of the acetabular fixation by closing the periacetabular fixation frame without requiring an additional posterior approach. The osseous screw corridor for infraacetabular screws use the transition zone between the acetabular ring and the obturator ring. The infraacetabular screw corridor (IAC) shows a double-cone shape with an isthmus located near the acetabular fovea. The iliopectineal eminence (IE) is mainly used as a clinical landmark for the intraoperative assessment of the entry point of IAS. The inlet view, the combined obturator oblique outlet view and a 1/3 iliac oblique outlet view may be used for the intraoperative radiological assessment for both the entry point and the screw trajectory of IAS. Several biomechanical studies have shown that IAS increase the stiffness of the internal fixation. Scientific proof for an improved clinical outcome is still missing., Competing Interests: Declarations Conflict of interest No author has a conflict of interest that related to the content discussed in this manuscript. All authors have contributed to and read the paper and have given permission for their names to be included as an author. The manuscript has not already been published and will not be submitted or published simultaneously elsewhere., (© 2024. The Author(s).)

Screw fixation of acetabular column fractures is a well-established alternative option to plate fixation providing comparable biomechanical strength and requiring less surgical exposure. For displaced acetabular fractures involving both columns open reduction and plate fixation of one column in combination with a column-crossing screw fixation of the opposite column via a single approach is a viable treatment option. Preoperative planning of posterior column screws (PCS) via an anterior approach is mandatory to assess the eligibility of the fracture for this technique and to plan the entry point and the screw trajectory. The intraoperative application requires fluoroscopic guidance using several views. A single view showing an extraarticular screw position is adequate to rule out hip joint penetration. The fluoroscopic assessment of cortical perforation of the posterior column requires several oblique views such as lateral oblique views, obturator oblique views and axial views of the posterior column or alternatively intraoperative CT scans. The application of PCS via an anterior approach is a technically demanding procedure, that allows for a relevant reduction of approach-related morbidity, surgical time and blood loss by using a single approach., Competing Interests: Declarations Conflict of interest The authors declare that they have no conflict of interest. No funding was received for this work., (© 2024. The Author(s).)

Introduction: The aim of this study was to compare the clinical, radiological and functional outcomes between cannulated compression screw with cable construct (CS) and tension band wiring (TBW) in transverse patella fractures., Materials and Methods: A retrospective study was conducted on patients surgically treated for AO/OTA 34C1 or 34C2 transverse patella fractures with CS or TBW technique between January 2019 and January 2023. Clinical outcomes included complications related to the implant, wound and fracture at 6 months and 1 year, time to achieving full weight bearing status and early perioperative clinical outcomes. Radiological outcomes included the time to fracture heals and delayed union. Functional outcome measures using the Oxford Knee Scale, 36-short form questionnaire and the Bartlett Anterior Knee Score were assessed., Results: 73 patients were treated with CS (n = 33) or TBW (n = 40). TBW had higher complication rates: 25.0% (n = 10) required implant removal, 12.5% (n = 5) had wire breakage, 12.5% (n = 5) experienced fracture displacement while 52.5% (n = 21) experienced implant migration. In contrast, no CS patients had implant removals, wire breakage or fracture displacement and 3.0% (n = 1) experienced implant migration. At 1 day post-operatively, 87.9% (n = 29) CS group patients were able to ambulate as compared to the 55.0% (n = 22) of TBW patients. Furthermore, CS patients ambulated further distances at 11.8 ± 10.6 m than the TBW group (6.4 ± 7.4 m). The CS group (25.9 ± 24.6 days) also achieved full weight bearing status faster than the TBW group (43.6 ± 39.4 days). The time taken for the fracture to heal and functional outcomes were comparable among the two groups., Conclusions: The CS technique demonstrated lower complications, in particular, no CS patient had implant removals, wire migration or fracture displacement. Additionally, CS technique showed a faster return to ambulation and time to achieving full weight bearing status., Competing Interests: Declarations Competing interests The authors have no relevant financial or non-financial interests to disclose., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Acute syndesmosis tears can be treated by static screw or dynamic fixation. Various studies have compared these techniques regarding postoperative outcome. However, to our knowledge, no study has used 3D-instrumented gait analysis (IGA). We hypothesized that a dynamic fixation would perform non-inferior to screw fixation in terms of biomechanical and clinical outcomes., Materials and Methods: Patients were prospectively randomized to both groups. All patients received the same follow-up rehabilitation and consultations (6 and 12 weeks; 6 and 12 months) postoperatively. Standardized questionnaires were used to objectify pain and ankle function. At 6 months follow-up, IGA was conducted additionally to objectify the biomechanical outcome., Results: Twenty-five patients in the dynamic fixation (DF) group using TightRope® and twenty-five in the screw fixation group (SF) completed gait analysis. The DF group showed significantly higher mean values for maximum moment in the affected ankle joint (DF: 1.40 ± 0.21 Nm, SF: 1.23 ± 0.30 Nm; p = 0.023) and the unaffected ankle joint (DF: 1.52 ± 0.20 Nm, SF: 1.37 ± 0.27 Nm; p = 0.035). The difference between the affected and unaffected ankle joint was significantly higher in the SF group for active plantarflexion (DF: 1.52 ± 0.20°, SF: 1.37 ± 0.27°; p = 0.035). Both dynamic and screw fixation groups exhibited significantly reduced plantarflexion during the push-off and early swing phase, with moments and powers in the ankle joint also significantly impaired., Conclusions: Our study demonstrated that dynamic fixation has better or similar biomechanical and clinical outcomes compared to screw fixation. Future research should focus on biomechanical differences during gait as well as clinical outcomes in case of earlier weight-bearing after dynamic fixation., Trial Registration Number (trn): DRKS00013562 Date of Registration: 07/12/2017., Competing Interests: Declarations Conflict of interest The authors have no relevant financial or non-financial interests to disclose. The authors have no competing interests to declare that are relevant to the content of this article. All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. The authors have no financial or proprietary interests in any material discussed in this article. Ethical approval This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the local Ethics Committee of the University/ Institutional Review Board (S-454/2017). Consent to participate Informed consent was obtained from all individual participants included in the study. Institutional review board (IRB) approval S-454/2017 RCT We confirm, that this study was registered as a RCT prospectively. Trial Registration Number (German Clinical Trials Register): DRKS00013562. Date of Trial Registration: 07/12/2017. Date of commencement of the study: 08/15/2017. Date of enrolement/recruitment of study subjects: 01/01/2018., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Acute total hip arthroplasty has gained increasing popularity in the treatment of complex acetabular fractures in elderly patients, but the biomechanical evidence is lacking. Therefore, we measured the primary stability to evaluate whether acute total hip arthroplasty using a multi-hole acetabular cup and posterior column plating through a single K-L approach can safely be used for treating complexed acetabular fractures in the elderly., Methods: In 18 composite osteoporotic hemipelves, T-type acetabular fractures were treated in three ways: CSP (Cup with acetabular screws augmentation combined with posterior plate) group, CP (Cup without acetabular screw combined with posterior plate) group and CSPA (Cup with acetabular screws combined with posterior plate and anterior plate) group. Each specimen was dynamically loaded (300 to 1700 N, 1 Hz). Primary stability of the acetabular cup and fracture gap was evaluated by 3-dimensional (3D) micromotions., Results: No significant differences in the 3D-micromotions were observed among the CSP, CP and CSPA groups except the test point on the anterior column of the acetabulum in the CP scenario (CSP 49.33 ± 21.08 μm vs. CP 224.83 ± 52.29 μm, p < 0.001; CSPA 45.50 ± 12.16 μm vs. CP 224.83 ± 52.29 μm, p < 0.001). No significant differences in the fracture gap displacement on the posterior column of acetabulum were observed among the CSP, CP and CSPA groups., Conclusion: Our results show, that acute total hip arthroplasty using a multi-hole cup with acetabular screws and posterior column plating through single a K-L approach offers good primary stability to allow good osseous integration for treating complex acetabular fractures in the elderly. Furthermore, it also provides good fracture gap displacement on the posterior column., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Clavicular midshaft fractures treated with titanium plates may encounter complications like implant failure. We assess if alternative biocompatible materials suchs as PLA, PLA/HA, PEEK offer comparable stability. Our study evaluates the biomechanical performance of these materials in surgical management of midshaft clavicle fractures., Methods: We simulated a personalized fixation implant with four different materials and conducted finite element analysis in ANSYS to assess maximum von Mises stress (MvMs)., Results: The MvMs occurring on the plates, screws, clavicle, and fracture site were recorded. MvMs on titanium material at the 6th hole level (764.79 MPa) and the 6th screw level (503.38 MPa), with the highest stresses observed at 48.52 MPa on the lateral clavicle at the 1st hole level and 182.27 MPa on the medial clavicle at the 6th hole level. In PLA material analyses, the highest MvMs were observed at the 3rd hole level (340.6 MPa) and the 3rd screw level (157.83 MPa), with peak stresses at 379.63 MPa on the lateral clavicle fracture line and 505.44 MPa on the medial clavicle fracture line. In PLA/HA material analyses, the highest MvMs were at the 3rd hole (295.99 MPa) and 3rd screw (128.27 MPa), with peak stresses at 220.33 MPa on the lateral clavicle and 229.63 MPa on the medial clavicle fracture line. In PEEK material analyses, the highest MvMs were at the 3rd hole (234.74 MPa) and 6th screw (114.48 MPa), with peak stresses at 184.36 MPa on the lateral clavicle and 180.1 MPa on the medial clavicle., Conclusion: Our findings indicate that titanium material shows significantly higher stresses on plates and screws compared to those on the clavicle, suggesting a risk of implant failure. PLA and PLA/HA were inadequate for fixation. Although stress on the plate with PEEK material is higher than on the clavicle, it remains lower than titanium, indicating potential stability at fracture site. Further research is needed to confirm these findings., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: The ideal surgical management for tibial eminence avulsion fractures remains controversial with varying approach, methods of fixation and post-operative regimes reported throughout literature. The current systematic review and meta-analysis aims to compare between the different approaches, methods of fixation and post-operative regimes for tibial eminence fractures., Methods: The systematic review was conducted according to PRISMA guidelines. A search was conducted using PubMed, MEDLINE and CINAHL databases. The keywords used were "anterior cruciate ligament", "tibial spine" or "tibial eminence" and "fracture" or "avulsion". All original human studies that reported the surgical outcomes of tibial eminence fractures were included. Individual patient data meta-analysis was performed., Results: 48 studies with 1367 patients were included. Arthroscopic fixation resulted in significantly greater stability in terms of anterior drawer test (p = 0.018) and Lachman's test (p = 0.042), as compared to open fixation, though there was no significant difference for pivot shift test. There was no significant difference identified in functional scores and activity, including Lysholm score, IKDC subjective score, Tegner score and return to sports. Suture fixation had significantly increased stability compared to screw fixation, in terms of anterior drawer test (p = 0.001) and Lachman's test (p = 0.001), though no significant difference was identified for pivot shift test. Significantly better subjective scores and return to activity were also noted for suture fixation, in terms of Lysholm score (p = 0.008), IKDC subjective score (p = 0.001) and Tegner score (p = 0.001), though no significant difference was identified for return to sports., Conclusion: Arthroscopic and suture fixation had significantly superior outcomes when compared to open and screw fixation. Arthroscopic fixation resulted in significantly improved stability of the knee as compared to open fixation, though no significant difference was identified in terms of functional knee scores and return to activity. Suture fixation resulted in significantly improved stability of the knee and functional knee screws as compared to screw fixation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this technical report study, we describe technique for performing the osteotomy and screw passage in minimally invasive fourth-generation hallux valgus surgery with transverse and akin extra-articular metaphyseal osteotomy (META) using a 3D-printed patient-specific surgical instrumentation guide. In an effort to minimize the learning curve and address the variability associated with technical corrections and screw placement, we have initiated the creation of personalized patient-specific instrumentation guides using 3D printing. Our hypothesis is that this approach will enhance safety, precision, decrease surgical time, and reduce exposure to radiation. Level of Evidence: Level V, expert opinion., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Proximal humerus fractures are usually treated with locking plates, which could present recurrence, screw penetration, joint varization. The push-pull principle was introduced to prevent these risks and showed promising results; a dedicated design was then developed and this feasibility study aims to compare the biomechanical performances of such dedicated push-pull plate with the traditional locking plate using finite elements., Materials and Methods: The humerus geometry was obtained from Sawbone CT-scans; the geometries of a traditional locking plate and of the dedicated push-pull one were used. A fracture was added below the humeral head and the plates were virtually implanted. The wire pulling mechanism was simulated connecting the plate to the humeral head apex, considering two levels of tension. Three testing set-ups (axial, torsion and compression bending) were simulated. Stress distributions on bone, plate and screws were measured., Results: Stress distribution on the distal humerus was similar for both plates. Stress distribution on the proximal humerus was more homogeneous for the push-pull model, showing less unloaded sections (up to 78%). The different levels of tension applied to the wire returned slight differences in terms of stress values, but the comparison with the traditional approach gave similar outcomes., Conclusions: More homogeneous stress distribution is found with the push-pull plate in all three testing set-ups, showing lower unloaded areas (and thus lower stress-shielding) compared to the traditional plate; the screws implemented returned to be all loaded in at least one of the set-ups, thus showing that they all contribute to plate stability., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The present meta-analysis evaluated current level I clinical trials which compared the use of a suture button (SB) versus syndesmotic screw (SS) fixation techniques for syndesmosis injuries of the ankle. The outcomes of interest were to compare patient-reported outcome measures (PROMs) and complications. It was hypothesised that SB might achieve better PROMs along with a lower rate of complications., Methods: This study was conducted according to the 2020 PRISMA statement. In August 2023, PubMed, Web of Science, Google Scholar, and Embase were accessed. All the randomised controlled trials (RCTs) which compared SB versus SS fixation for syndesmosis injuries of the ankle were accessed. Data concerning the American Orthopaedic Foot & Ankle Society (AOFAS), and Olerud-Molander score (OMS) were collected at baseline and at last follow-up. Data on implant failure, implant removal, and joint malreduction were also retrieved., Results: Data from seven RCTs (490 patients) were collected. 33% (161 of 490) were women. The mean length of the follow-up was 30.8 ± 27.4 months. The mean age of the patients was 41.1 ± 4.1 years. Between the two groups (SB and SS), comparability was found in the mean age, and men:women ratio. The SS group evidenced lower OMS (P = 0.0006) and lower AOFAS (P = 0.03). The SS group evidenced a greater rate of implant failure (P = 0.0003), implant removal (P = 0.0005), and malreduction (P = 0.04)., Conclusion: Suture button fixation might perform better than the syndesmotic screw fixation in syndesmotic injuries of the ankle., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Traditionally, plate osteosynthesis of the anterior column combined with an antegrade posterior column screw is used for fixation of anterior column plus posterior hemitransverse (ACPHT) acetabulum fractures. Replacing the posterior column screw with an infraacetabular screw could improve the straightforwardness of acetabulum surgery, as it can be inserted using less invasive approaches, such as the AIP/Stoppa approach, which is a well-established standard approach. However, the biomechanical stability of a plate osteosynthesis combined with an infraacetabular screw instead of an antegrade posterior column screw is unknown., Material and Methods: Two osteosynthesis constructs were compared in a synthetic hemipelvis model with an ACPHT fracture: Suprapectineal plate + antegrade posterior column screw (APCS group) vs. suprapectineal plate + infraacetabular screw (IAS group). A single-leg stance test protocol with an additional passive muscle force and a cyclic loading of 32,000 cycles with a maximum effective load of 2400 N was applied. Interfragmentary motion and rotation of the three main fracture lines were measured., Results: At the posterior hemitransverse fracture line, interfragmentary motion perpendicular to the fracture line (p < 0.001) and shear motion (p < 0.001) and at the high anterior column fracture line, interfragmentary motion longitudinal to the fracture line (p = 0.017) were significantly higher in the IAS group than in the APCS group. On the other hand, interfragmentary motion perpendicular (p = 0.004), longitudinal (p < 0.001) and horizontal to the fracture line (p = 0.004) and shear motion (p < 0.001) were significantly increased at the low anterior column fracture line in the APCS group compared to the IAS group., Conclusions: Replacing the antegrade posterior column screw with an infraacetabular screw is not recommendable as it results in an increased interfragmentary motion, especially at the posterior hemitransverse component of an ACPHT fracture., (© 2024. The Author(s).)

Introduction: The standard surgical procedure for unstable ankle fractures is fixation of the lateral malleolus with a plate and screws. This method has a high risk of complications, especially among patients with fragile skin conditions. The aim of this study was to estimate the re-operation rates and identify complications in patients with an unstable ankle fracture, surgically treated with an intramedullary screw or rush pin., Materials and Methods: We identified all patients who were surgically treated with either a 3.5-mm screw or rush pin at Aarhus University Hospital, Denmark, from 2012 to 2018. Major complications were re-operations within three months. We included 80 patients, of which 55 (69%) were treated with a 3.5-mm intramedullary screw and 25 (31%) with a rush pin. The majority of the study population was female (59) and the mean age was 75 (range 24 to 100) years. Of the 80 patients included, 41 patients had more than 2 comorbidities., Results: Three patients underwent re-operation within three months due to either fracture displacement or hardware cutout. Radiographs obtained after six weeks showed that nine patients had loss of reduction. Additionally, four patients had superficial wound infections and six patients had delayed wound healing., Conclusions: Intramedullary fixation of distal fibula fractures with either a screw or rush pin has low re-operation rates. However, the high proportion of patients with radiological loss of reduction is concerning., (© 2024. The Author(s).)

Introduction: Time-efficiency of individually wrapped screws versus screws in a screw rack is not well established., Materials and Methods: We performed a prospective single-center clinical study timing the interval between the surgeon asking and receiving a screw during plate and screw osteosynthesis of distal radius fractures. Patients were randomized for individually wrapped screws or screws in a screw rack. The study was conducted in a Level 1 Trauma Center and surgeries were performed between March and June 2023., Results: Average handling time for screws from a screw rack was 9 s (SD 5.5; range 3-28) and 22 s for individually wrapped screws (SD 6.1; range 6-38). This average difference of 13 s is significant (p < 0.0001)., Conclusion: There is a significant increase in handling time using individually wrapped screws over using a screw rack., Level of Evidence: Level I (therapeutic, randomized controlled trial)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: To date, the approach that prevails in the open reduction and internal fixation of crescent fracture-dislocations (CFD) remains unknown. This study aimed to compare the outcomes of CFD treated via the anterior or posterior approach., Materials and Methods: Data from 64 cases of CFDs openly reduced through an anterior (group A, n = 31) or a posterior (group B, n = 33) approach were retrospectively analyzed. Functional results, reduction quality, residual displacements in the axial and coronal planes, pelvic asymmetry deformity, and correlations between Day's classification were compared. Complications and fracture union were also recorded. All patients were followed up for at least 12 months., Results: The functional scores were similar between the two groups, and all fractures achieved good or excellent reduction postoperatively. In the coronal plane, the excellent/good ratio in group B was higher than in group A. The mean residual displacement in the coronal plane was significantly higher in group A than in group B, with group A showing greater displacement in both planes for Day I fractures and in the coronal plane for Day II fractures. The residual displacement in both planes for Day III fractures was comparable between the groups. The pelvic asymmetry deformity was equal between the two groups and among the different Day's fracture types., Conclusions: Open reduction and internal fixation of CFDs obtained satisfactory outcomes through an anterior or posterior approach. The posterior approach achieved a better sacroiliac joint reduction. The optimal indication for the posterior approach was a Day I fracture, followed by a Day II fracture. No correlation was found between the surgical approach and reduction quality in Day III fractures., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: After locking plate (LP) fixation, secondary screw perforation (SSP) is the most common complication in proximal humerus fracture (PHF). SSP is the main cause of glenoid destruction and always leads to reoperation. This study aimed to identify independent risk parameters for SSP and establish an individualized risk prognostic model to facilitate its clinical management., Methods: We retrospectively reviewed the medical information of patients with PHF who underwent open reduction and internal LP fixation at one medical center (n = 289) between June 2013 and June 2021. Uni- and multivariate regression analyses identified the independent risk factors. A novel nomogram was formulated based on the final independent risk factors for predicting the risk of SSP. We performed internal validation through concordance indices (C-index) and calibration curves. To implement the clinical use of the model, we performed decision curve analyses (DCA) and risk stratification according to the optimal cutoff value., Results: A total of 232 patients who met the inclusion criteria were enrolled. The incidence of SSP was 21.98% at the last follow-up. We found that fracture type (odds ratio [OR], 3.111; 95% confidence interval [CI], 1.223-7.914; P = 0.017), postoperative neck-shaft angle (OR, 4.270; 95% CI 1.622-11.239; P = 0.003), the absence of calcar screws (OR, 3.962; 95% CI 1.753-8.955; P = 0.003), and non-medial metaphyseal support (OR,7.066; 95% CI 2.747-18.174; P = 0.000) were independent predictors of SSP. Based on these variables, we developed a nomogram that showed good discrimination (C-index = 0.815). The predicted values of the new model were in good agreement with the actual values demonstrated by the calibration curve. Furthermore, the model's DCA and risk stratification (cutoff = 140 points) showed significantly higher clinical benefits., Conclusions: We developed and validated a visual and personalized nomogram that could predict the individual risk of SSP and provide a decision basis for surgeons to create the most optional management plan. However, future prospective and externally validated design studies are warranted to verify our model's efficacy., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To compare union rate, union time, alignment, and complication rate in ipsilateral tibia plateau and shaft fractures treated via suprapatellar intramedullary nailing with screw fixation and minimally invasive locking plate fixation., Materials and Methods: A retrospective study was conducted on 48 patients who underwent minimally invasive plate fixation (n = 35) or suprapatellar intramedullary nailing with screw fixation (n = 13), for the treatment of ipsilateral tibial plateau and shaft fractures with at least 1-year follow-up. Union rate, union time, radiologic alignment, and complication rate such as malalignment, nonunion, and fracture-related infection (FRI) were investigated., Results: Demographic data were not different between the two groups. Coronal plane alignment was 0.17 ± 4.23 in the plate group and -0.48 ± 4.17 in the intramedullary nail group (p = 0.637). Sagittal plane alignment was -0.13 ± 5.20 in the plate group and -1.50 ± 4.01 in the suprapatellar intramedullary nail group (p = 0.313). Coronal and sagittal malalignment recorded equal results: (p > 0.99), FRI (p = 0.602), nonunion and union times recorded (p = 0.656) and (p = 0.683, 0.829), respectively, and showed no significant difference between the two groups., Conclusion: Suprapatellar intramedullary nailing with screw fixation had similar surgical outcomes with minimally invasive locking plate fixation in ipsilateral tibial plateau and shaft fractures in terms of union rate, union time, alignment, and complication rate. Thus, frequent use of intramedullary nailing combined with screw fixation is anticipated in patients with ipsilateral tibial plateau and shaft fractures when the soft tissue condition is not desirable., Level of Evidence: Level III., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Subtrochanteric femur fractures treated with intramedullary nails present biomechanical benefits, early weight-bearing, and reduced soft tissue damage, promoting bone union. However, improper reduction due to muscular forces and fragmented proximal bone increases nonunion risk. This study evaluates the efficacy of the blocking screw technique in preventing malalignment during intramedullary nailing., Material and Methods: In cases of subtrochanteric femoral fractures where malalignment, such as varus and anterior angulation, was anticipated during intramedullary nailing, proper reduction was ensured using blocking screw technique on the proximal bone fragment from the coronal or sagittal plane. A retrospective analysis was conducted on 25 patients (14 males, 11 females; average age 55.12 years) who were followed up for more than 1 year. The postoperative neck-shaft angle, anterior angulation angle, and limb length discrepancy were compared radiologically with those on the healthy side, and the presence and duration of bone union were measured. The Harris hip score was used for functional evaluation, and complications, including infection, were analyzed., Results: At the final follow-up, primary bone union was achieved in 21/25 patients (84%), with an average bone union time of 21.81 weeks (range, 14-42 weeks). Of the four nonunions, bone union was achieved in three cases through bone grafting and supplemental plating and in the other case through intramedullary exchange, supplemental plating, and bone grafting. The femoral neck-shaft angle and anterior angulation showed no statistically significant differences compared with the healthy side, with averages of - 1.15° and - 1.4°, respectively. The limb length discrepancy was an average of - 2.4 mm. Regarding functional outcomes, the Harris hip score averaged 89.52 points (range 82-94 points)., Conclusions: In subtrochanteric femoral fractures, the blocking screw technique effectively prevents malalignment during intramedullary nailing, ensuring not only appropriate reduction but also high bone union rates., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Optimal surgical fixation for displaced intra-articular calcaneal fractures (DIACF) remains a subject of debate, particularly regarding the superiority between screw fixation and plate fixation via the sinus tarsi approach (STA). This review aims to determine the preferred treatment for DIACF and compare the outcomes of minimally invasive surgery options., Methods: Our study involved thorough searches across multiple electronic databases, including PubMed, Cochrane, Embase, and Web of Science, to identify all relevant publications on distal intra-articular fractures of the calcaneus (DIACFs) that were fixed using cannulated screws or plates via STA. Through a comprehensive meta-analysis, we evaluated several outcomes, including post-operative function, radiological measurements, and complications., Result: A total of 728 patients from 7 studies met the inclusion criteria. Among them, 435 patients underwent screw fixation via STA, and 373 patients underwent plate fixation via STA. The study found no statistically significant differences between the screw fixation and the plate fixation via sinus tarsi approach (STA) in terms of AOFAS scores, Bohler's angle, Gissane's angle, sural nerve injury, secondary subtalar arthrodesis and reoperation. Compared with screw fixation, plate fixation via STA can reduce reduction loss of Bohler's angle (WMD = - 1.64, 95% CI = [- 2.96, - 0.31], P = 0.06, I 2  = 59%), lower the incidence of fixation failure (OR = 0.32, 95% CI = [0.13, 0.81], P = 0.78, I 2  = 0%), and decrease intra-articular step-off (WMD = - 0.52, 95% CI = [- 0.87, - 0.17], P = 0.66, I 2  = 0%)., Conclusions: Plate fixation demonstrates superior capability in restoring calcaneal width, maintaining Bohler's angle, and minimizing intra-articular step-off, thereby maintaining better reduction of the subtalar articular surface. In addition, plate fixation exhibits the modest complication rate and a low incidence of fixation failure. Therefore, we recommend the use of plate fixation through the STA, especially for complex and comminuted intra-articular calcaneal fractures., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Distal radius fractures are the most commonly reported fractures in adults. Treatment has changed in recent years to open reduction and palmar plate fixation. Penetration of the dorsal screw, however, is a well-known complication. Intraoperative anteroposterior and lateral radiographs lack the exact assessment of dorsal screw length and intraoperative measurement is therefore very likely to be inaccurate in a comminuted dorsal radial cortex. Secondary extensor tendon ruptures are reported in up to 6% following palmar plate fixation of distal radius fracture., Materials and Methods: A prospective randomized trial was performed to assess the value of the dorsal horizon view. The hypothesis was that the traditional anteroposterior and lateral fluoroscopic views aided by an axial view of the dorsal part of the radius, named dorsal horizon view, could prevent dorsal screw penetration. A total of 40 patients, 6 male and 34 female, were included in the study. Standardized anteroposterior and lateral radiographs were performed intraoperatively in 18 patients (standard group = control group). In 22 patients, intraoperative axial fluoroscopic views (dorsal horizon view) were added to anteroposterior and lateral images (horizon group). Numbers of intraoperative screw changes due to the two different radiological examinations were analyzed as well as exact postoperative CT guided measurement of screw length., Results: The total numbers of intraoperative screw changes were significantly higher in the horizon group. Forty-two screws were changed in 15 patients in the horizon group while only 8 screws were changed in 3 patients in the standard group. Postoperative computed tomography scans showed significantly lower total numbers of perforating screws in the horizon group with 11 screws in 22 patients compared to 20 screws in 18 patients in the standard group (p = 0.02)., Conclusions: Based on the results of this study, the dorsal horizon view improves the assessment of the correct screw length and should routinely be used in palmar plate osteosynthesis of distal radius fractures. Since screw protrusion cannot be absolutely ruled out using the dorsal horizon view, monocortical drilling or screw downsizing is still mandatory., Trial Registration: This clinical trial was not registered because it was a clinical examination without any experimental techniques., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The STRYKER ADAPT computer-assisted navigation system provides intraoperative feedback to the surgeon regarding implant placement of the Gamma3 nail. The usability of the ADAPT system has not been evaluated. The aim of the study was to investigate the perceived usability of the ADAPT system., Materials and Methods: This was a descriptive study with prospectively collected data. ADAPT was introduced at Aarhus University Hospital in February 2021. Prior to introduction, surgeons at the department attended a general introduction to the system. ADAPT was introduced to the surgical nurses and was on display at the surgical ward at more than one occasion, where personal introduction to the system was possible. After introduction, it was mandatory to use ADAPT when using the Gamma3 nail to treat intertrochanteric femur fractures. After each procedure, primary and an eventual supervisor answered a questionnaire, which encompassed the System Usability Scale (SUS) questionnaire. The SUS is a ten-item questionnaire regarding the perceived usability of a system. SUS scores were translated to adjectives, describing user experience on a 7-point adjective scale (worst imaginable, awful, poor, ok, good, excellent, best imaginable). User acceptability, defined as "not acceptable", "marginal" or "acceptable", was also used to interpret the SUS scores., Results: ADAPT was used in 50 procedures by 29 different surgeons, with varying skill-level. Median SUS-score after first-time use of ADAPT for all 29 surgeons was 43 (range: 5-60), which translated to "poor" or "not acceptable". For surgeons who performed ≥ 3 ADAPT-assisted procedures, there were no statistically significant difference in their first to latest SUS-score (median difference: 4.3, p = 0.5). In free text comments ADAPT was positively described as helpful in placement of K-wire and providing educational opportunities for inexperienced surgeons and negatively as inconsistent, slow, time consuming, and causing excessive fluoroscopy., Conclusions: Usability and acceptability of ADAPT was rated as "poor" or "not acceptable" by the majority of operating surgeons. ADAPT has not been used at our institution based on these findings. The System Usability Scale may be used in further research exploring usability and acceptability of novel computer-assisted navigation systems for orthopaedic surgery., (© 2023. The Author(s).)

Failure of osteosynthesis is a common complication of the nailing of trochanteric fractures which typically occurs through form of cut-out. Tip-Apex distance (TAD), Calcar Tip-Apex distance (CalTAD), and Chang criteria are validated variables to predict failure of cephalomedullary nailing. This is a retrospective study which analyzes treatment of trochanteric fractures from 2018 to 2020 (n = 296) evaluating postoperative radiographs and factors of mechanical failure. Our objective was to assess correlation among these variables and their influence on mechanical failure, either individually or creating a new score. Our results support the CalTAD and Chang's criteria as valid predictors of mechanical failure. Furthermore, they empathize the importance of fracture reduction and proper placement of cervical screw. To our knowledge, this is the first study performing multivariate analysis including these 3 variables., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The optimal internal fixation for non-displaced femoral neck fractures remains controversial. This study aimed to compare the clinical results of the percutaneous compression plate (PCCP) with parallel screws (PS) in treating femoral neck fractures in elderly patients., Materials and Methods: A total of 218 patients who underwent internal fixation were randomized to receive either a percutaneous compression plate (PCCP group) or parallel screws (PS group) using a computerized random sequence generator which was used to assign the order of randomization. Patients were assessed by the operating time, intraoperative blood loss, hemoglobin level drop, postoperative hospital stay, the time to full weight-bearing, reduction quality, fracture healing time, Harris hip score, and postoperative complications., Results: There was no significant difference between PCCP and PS groups regarding operative time, intraoperative blood loss, hemoglobin level drop, postoperative hospital stays, reduction quality, and Harris hip score (p > 0.05). The time to full weight-bearing and the fracture healing time in the PCCP group were shorter than those in the PS group (p < 0.05). The overall complication rates were slightly lower in the PCCP compared to the PS patients, but there was no significant difference (p > 0.05). However, the implant failure rate was significantly higher in the PS group compared to the PCCP group (p < 0.05)., Conclusions: The present study suggests that the PCCP is superior to the parallel screws fixation in the treatment of non-displaced elderly femoral neck fractures in terms of earlier full weight-bearing, shorter fracture healing time, and lower implant failure rate. Therefore, it may be a better therapeutic strategy for non-displaced femoral neck fractures in elderly patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The purpose of this study is to (1) describe a pre-operative planning technique using non-reformatted CT images for insertion of multiple transiliac-transsacral (TI-TS) screws at a single sacral level, (2) define the parameters of a sacral osseous fixation pathway (OFP) that will allow for insertion of two TI-TS screws at a single level, and (3) identify the incidence of sacral OFPs large enough for dual-screw insertion in a representative patient population., Methods: Retrospective review at a level-1 academic trauma center of a cohort of patients with unstable pelvic injuries treated with two TI-TS screws in the same sacral OFP, and a control cohort of patients without pelvic injuries who had CT scans for other reasons., Results: Thirty-nine patients had two TI-TS screws at S1. Eleven patients, all with dysmorphic osteology, had two TI-TS screws at S2. The average pathway size in the sagittal plane at the level the screws were placed was 17.2 mm in S1 vs 14.4 mm in S2 (p = 0.02). Twenty-one patients (42%) had screws that were intraosseous and 29 (58%) had part of a screw that was juxtaforaminal. No screws were extraosseous. The average OFP size of intraosseous screws was 18.1 mm vs. 15.5 mm for juxtaforaminal screws (p = 0.02). Fourteen millimeters was used as a guide for the lower limit of the OFP for safe dual-screw fixation. Overall, 30% of S1 or S2 pathways were ≥ 14 mm in the control group, with 58% of control patients having at least one of the S1 or S2 pathways ≥ 14 mm., Conclusions: OFPs ≥ 7.5 mm in the axial plane and 14 mm in the sagittal plane on non-reformatted CT images are large enough for dual-screw fixation at a single sacral level. Overall, 30% of S1 and S2 pathways were ≥ 14 mm and 58% of control patients had an available OFP in at least one sacral level., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Posterior column fractures are common acetabular injuries. Although displaced fractures require open reduction and fixation, undisplaced patterns may benefit from percutaneous screw fixation. The combination of iliac oblique with inlet and outlet views offers an intuitive and panoramic rendering of the bony corridor into the posterior column; lateral cross table view completes the sequence of fluoroscopic projections. Herein we describe the use of outlet/inlet iliac views and a detailed procedure for percutaneous retrograde posterior column screw fixation., (© 2023. The Author(s).)

Introduction: Patella fractures account for approximately 1% of all bone fractures. The tension band wiring technique has been used in surgical treatment. However, there is no clear information about the location of the K-wires in sagittal plane. Thus, a transverse fracture line was created in the patella finite element model and fixed with Kirchner (k) wires and cerclage at different angles and compared with two different standard tension band models., Materials and Methods: A total of 10 finite element models were created to study AO/OTA 34-C1 patella fractures. Two models used the classical tension band method with either circumferential or 8-shaped cerclage wire. The other 8 models used K-wires placed at 45° or 60°, either alone or combination with cerclage wire. A force of 200 N, 400 N, and 800 N were applied at 45° knee angle and the resulting data fracture line opening, surface pressure and stress in the implants were analyzed through finite element analysis., Results: When all the results are considered, it was determined that the K-wires 60° crossing at the fracture line and with cerclage modeling was superior to the other models. The diagonal placement of the K-wires with cerclage (could be 45° or 60° medium) was superior to the reference models., Conclusions: This study has shown that the new fixation method we propose could come to the fore as an alternative method to be used successfully in transverse patella fractures and lower complications. In transverse patellar fractures, the use of K-wires crossed at 60° may be a good alternative to the standard method., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Nailing of the proximal humerus is an established method for the treatment of proximal humerus fractures. Choice of the correct length for potentially four proximal locking screws is essential for postoperative outcome. Due to positioning of the patient, intraoperative determination of the correct length of the anteroposterior (AP) screw with the x-ray beam is particularly challenging even for experienced surgeons. We hypothesized that there would be a correlation between the projected lengths of the different proximal locking screws and therefore the length of the AP-screw could be determined based on the three lateromedial (LM) screws., Materials and Methods: In this retrospective study (level of evidence: III) CT-scans of shoulders of 289 patients were 3D reconstructed with the program Horos. Using the manufacturer Stryker's instructions, the four proximal locking screws of the T2 Humeral Nail system were reproduced in the 3D reconstructed shoulders. The length of the AP-screw was correlated with the lengths of the LM-screws by Linear Regression and Multiple Linear Regression., Results: The results of this study showed that the lengths of proximal locking screws in proximal humeral nailing correlated significantly with each other. Based on the given data, a formula could be established to calculate the length of the AP-screw based on the lengths of the LM-screws with a probability of 76.5%., Conclusions: This study was able to show that the length of the AP-screw could be determined from the intraoperatively measured lengths of the LM-screws. As our findings base on measurements performed in CT scans, clinical studies are needed to support our data., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: This systematic review and meta-analysis compared extramedullary fixation and intramedullary fixation for stable two-part trochanteric femoral fractures (AO type 31-A1) with regards to functional outcomes, complications, and surgical outcomes., Methods: Embase, Medline, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar were searched for randomized controlled trials (RCTs) and observational studies. Effect estimates were pooled across studies using random effects models. Results were presented as weighted risk ratio (RR) or weighted mean difference (MD) with corresponding 95% confidence interval (95% CI)., Results: Five RCTs (397 patients) and 14 observational studies (21,396 patients) were included. No significant differences in functional outcomes, complications, or surgical outcomes were found between extramedullary and intramedullary fixation devices, except for a difference in duration of surgery (MD 14.1 min, CI 5.76-22.33, p < 0.001) and intra-operative blood loss (MD 92.30 mL, CI 13.49-171.12, p = 0.02), favoring intramedullary fixation., Conclusion: Current literature shows no meaningful differences in complications, surgical, or functional outcomes between extramedullary and intramedullary fixation of stable two-part trochanteric femoral fractures. Both treatment options result in good outcomes. This study implicates that, costs should be taken into account when considering implants or comparing fixation methods in future research., (© 2023. The Author(s).)

Introduction: To evaluate the clinical and radiological results after fixation of the first metatarsal head (MTH) with one or two screws as part of the third-generation minimally invasive Chevron-Akin osteotomy (MICA) for hallux valgus deformities., Materials and Methods: Between August 2020 and November 2021, 55 MICA procedures (50 patients, male:female = 7:43), 22 with two (MICA2), 33 with one screw (MICA1) were performed for mild to severe hallux valgus deformities. Exclusion criteria were a concomitant pes adductus (Sgarlato angle > 20°) or hindfoot/midfoot deformities requiring treatment. In 27 cases, additional procedures on the forefoot (small toe corrections or metatarsal osteotomies II-V) were necessary. Pre- and post-operatively, hallux valgus angle (HVA) and intermetatarsal I/II angle (IMA) were measured. Clinically, subjective satisfaction, range of motion (ROM) of the first metatarsophalangeal joint (MTPJ), and pain level (NRS score) were evaluated. The minimum follow-up was 12 months., Results: Displacement of MTH was 70-90% on average, all osteotomies showed full consolidation at latest follow-up. In one case of either group, a slight subsidence of MTH was documented. The radiological and clinical parameters showed no differences between the groups. The pain level improved by an average of three points. The mobility of the MTPJ showed a slight reduction in nine cases after three months (4 MICA2, 5 MICA1) which persisted in three cases. Fifty-two of 55 patients (95%) would opt again for the operation., Conclusions: Fixation of the first MTH with a single bicortical screw in MICA with moderate lateralization of MTH shows stable anchoring and good clinical results. The routine use of a second metatarsal screw can be omitted., (© 2022. The Author(s).)

Introduction: The prime requisites of a good digital arthrodesis are a painless and stable union in a proper position. Arthrodesis of the distal interphalangeal joint of the fingers is not without potential complications including nonunion, malunion, and deep tissue infections. The Shark Screw ® is a human, cortical bone allograft for osteosynthesis and an alternative to metal or bioabsorbable devices in orthopedics and trauma surgery. The primary hypothesis is that the fusion and complication rate, using the Shark Screw ® , is at least similar to those reported in the literature, using metal or bioabsorbable screws., Material and Methods: This retrospective cohort study analyzes the fusion and complication rate and the patient satisfaction of distal interphalangeal joint arthrodesis of 27 fingers with the human allogeneic cortical bone screw. Complications, Disabilities of Arm, Shoulder, and Hand Questionnaire (Quick-DASH) score and Michigan Hand Outcomes Questionnaire (MHQ) score, grip and pinch strength and fusion angle were investigated., Results: The mean follow-up was 23 months. At 6 weeks after surgery, fusion was obtained for all fingers. There was no surgical complication that required revision surgery. An average fusion angle of 13.6° ± 10.7° was measured. VAS pain score decreased significantly from 6.9 before surgery to 0.14 after surgery. The Quick-DASH score decreased from 10.7 to 7.8. The MHQ score improved in all sub-scores., Conclusion: The complication rates, using the Shark Screw ® for DIP joint arthrodesis, are lower compared to the results reported in the literature for other surgical techniques. Complications related to the human allograft cortical bone screw itself were not observed. The bone screw is completely remodeled into the host bone and further hardware removal is not necessary., Level of Evidence: IV., (© 2023. The Author(s).)

Purpose: The optimal screw placement in arthroscopically assisted fixation of radial head fractures is still an issue and no guiding methods have been evaluated in the recent literature. The study hypothesis was that using a "reference k-wire" percutaneously inserted in and parallel to the radiocapitellar joint would enable to achieve a trajectory more parallel to the radial head articular surface as compared to a free-hand k-wire placement., Methods: Arthroscopically assisted placement of a k-wire in the radial head was performed in seven fresh-frozen human cadaver specimens by three surgeons. Three different techniques were evaluated: freehand drilling (technique A), placement using a "reference" k-wire in the radiocapitellar joint as a reference without (technique B), and with the AO parallel k-wire guide (technique C). Radiographs from all procedures were obtained and the inclination angle "α" between the k-wire and the articular surface of the radial head was measured and compared among the techniques., Results: Angles of 84 radiographs were obtained and showed a mean α angle of 30.1° ± 13° for technique A, 5.7° ± 4.5° for technique B, and 5.4° ± 3.7° for technique C. The angle α was significantly higher with technique A as compared to B (p < 0.0001) and C (p < 0.0001). There was no difference between methods B and C (n.s.). No difference was observed among the surgeons for all three methods (p = 0.66)., Conclusion: With the use of an additional "reference" k-wire placed in the radiocapitellar joint, the guiding k-wire for screw drilling can be placed almost parallel to the radial head joint line with limited variability and a good reproducibility during arthroscopically assisted radial head fracture fixation., Clinical Relevance: The here-presented method of an additional, percutaneous introduced "reference" k-wire is easily applicable and helpful to achieve parallel screw placement during arthroscopically assisted radial head fracture fixation., Level of Evidence: IV, biomechanical cadaver study., (© 2022. The Author(s).)

Introduction: Over the past years, different fixation techniques focused on rotational stability in order to increase stability and stimulate union rates. Additionally, extracorporeal shockwave therapy (ESWT) has gained importance in the treatment of delayed and nonunions. Purpose of this study was to compare the radiological and clinical outcome of two headless compression screws (HCS) and plate fixation in scaphoid nonunions, in combination with intraoperative high energy ESWT., Materials and Methods: Thirty-eight patients with scaphoid nonunions were treated by using a nonvascularized bone graft from the iliac crest and stabilization with either two HCS or a volar angular stable scaphoid plate. All patients received one ESWT session with 3000 impulses and energy flux per pulse of 0.41 mJ/mm 2 intraoperatively. Clinical assessment included range of motion (ROM), pain according to the Visual Analog Scale (VAS), grip strength, disability of the Arm Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien (Mayo) Wrist Score. To confirm union, a CT scan of the wrist was performed., Results: Thirty-two patients returned for clinical and radiological examination. Out of these, 29 (91%) showed bony union. All patients treated with two HCS compared to 16 out of 19 (84%) patients treated by plate showed bony union on the CT scans. The difference was not statistically significant. However, at a mean follow-up interval of 34 months, no significant differences could be found in ROM, pain, grip strength and patient-reported outcome measurements between the two HCS and plate group. Height-to-length ratio and capitolunate angle improved significantly in both groups compared to preoperative., Conclusions: Scaphoid nonunion stabilization by using two HCS or angular stable volar plate fixation and intraoperative ESWT results in comparable high union rates and good functional outcome. Due to the higher rate for a secondary intervention (plate removal), HCS might be preferable as first choice, whereas the scaphoid plate fixation should be reserved for recalcitrant (substantial bone loss, humpback deformity or failed prior surgical intervention) scaphoid nonunions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Hip fractures in the elderly population are common and the number of patients is rising. For young and geriatric patients with undisplaced fractures osteosynthesis is the primary type of treatment. The dynamic hip screw (DHS) is around for many years and proved its value especially in displaced fractures. Since 2018 the femoral neck system (FNS) is available as an alternative showing promising biomechanical results. The aim of this study is to evaluate clinical results of the FNS and compare it to the DHS., Materials and Methods: Patients older than 18 years with Garden I-IV fractures that were treated with osteosynthesis in a level 1 trauma center were included in the study. Between January 2015 and March 2021, all patients treated with FNS (1-hole plate, DePuy-Synthes, Zuchwil, Switzerland) or DHS (2-hole plate, DePuy-Synthes, Zuchwil, Switzerland) for proximal femur fractures were included in the study. Closed reduction was achieved using a traction table. All operations were carried out by experienced orthopedic trauma surgeons. Primary outcome measures were rate of implant failure (cut out) and surgical complications (hematoma, infection). Secondary outcome measures were Hb-difference, length of hospital stay and mortality., Results: Overall, 221 patients were included in the study. 113 were treated with FNS, 108 with DHS. Mean age was 69 ± 14 years. There were 17.2% Garden I, 47.5% Garden II, 26.7% Garden III and 8.6% Garden IV fractures. No difference between the groups for age, body mass index (BMI), Charlson comorbidity index (CCI), time to surgery, Pauwels and Garden classification, rate of optimal blade position or tip apex distance was found. FNS showed lower pre- to postoperative Hb-difference (1.4 ± 1.1 g/l vs. 2.1 ± 1.4 g/l; p < 0.05), shorter operating time (36.3 ± 11.6 min vs. 54.7 ± 17.4 min; p < 0.05) and hospital stay (8.8 ± 4.3 d vs. 11.2 ± 6.8 d; p < 0.05). Surgical complications (FNS 13.3% vs. DHS 18.4%, p > 0.05), rate of cut out (FNS 12.4% vs. DHS 10.2%, p > 0.05) and mortality (FNS 3.5%; DHS 0.9%; p > 0.05) showed no difference between the groups. Logistic regression showed that poor blade position was the only significant predictor for cut out and increased the risk by factor 7. Implant related infection (n = 3) and hematoma/seroma (n = 6) that needed revision was only seen in DHS group., Conclusion: FNS proved to be as reliable as DHS in all patients with hip fractures. Not the type of implant but blade positioning is still key to prevent implant failure. Still due to minimal invasive approach implant related infections and postoperative hematomas might have been prevented using the FNS., (© 2022. The Author(s).)

Background: Complex proximal humeral fracture ranks among the most common fracture types, especially in elderly patients. In locked plate fixation of proximal humerus fractures, the calcar is deciding for screws providing further medial column support. To date, the biomechanical effect of the length of these calcar screws is not well known. The purpose of this study was to analyze the effect of long calcar screws on fresh frozen prefractured cadaveric specimens., Methods: In the present biomechanical study, 8 pairs of cadaveric proximal humeri were fractured identically using a custom-made fracture simulator. ORIF was performed using a locking plate (PHILOS; Fa. Synthes). The specimens were tested in a biomechanical setup under increased axial load without any calcar screws installed, with short calcar screws and long calcar screws installed. Strain gages (4-wire-120 Ohm, Fa. Vishay) mounted on the locking plate were used to evaluate the fixation strain and to give an estimate for primary stability.., Results: The measured strain of the locking plate without calcar screws (804,64 µm/m) at maximum load (200 N) was significantly higher than with short (619,07 µm/m; p = 0.02) or long calcar screws (527,31 µm/m; p = 0.007). Additionally, strain with short calcar screws was noticeably higher in comparison to long calcar screws (619,07 µm/m vs. 527,31 µm/m; p = 0.03)., Conclusion: Use of calcar screws improves the stability of realistically impacted 3-part varus humeral fractures. Long calcar screws that are positioned as close as possible to the joint provide further primary stability compared to short calcar screws., Level of Evidence: Basic science study., (© 2022. The Author(s).)