Validity of a Novel Digitally Enhanced Skills Training Station for Freehand Distal Interlocking.

Background and Objectives: Freehand distal interlocking of intramedullary nails is technically demanding and prone to handling issues. It requires precise placement of a screw through the nail under fluoroscopy guidance and can result in a time consuming and radiation expensive procedure. Dedicated training could help overcome these problems. The aim of this study was to assess construct and face validity of new Digitally Enhanced Hands-On Surgical Training (DEHST) concept and device for training of distal interlocking of intramedullary nails. Materials and Methods: Twenty-nine novices and twenty-four expert surgeons performed interlocking on a DEHST device. Construct validity was evaluated by comparing captured performance metrics-number of X-rays, nail hole roundness, drill tip position and drill hole accuracy-between experts and novices. Face validity was evaluated with a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale. Results: Face validity: mean realism of the training device was rated 6.3 (range 4-7). Training potential and need for distal interlocking training were both rated with a mean of 6.5 (range 5-7), with no significant differences between experts and novices, p ≥ 0.234. All participants (100%) stated that the device is useful for procedural training of distal nail interlocking, 96% wanted to have it at their institution and 98% would recommend it to colleagues. Construct validity: total number of X-rays was significantly higher for novices (20.9 ± 6.4 versus 15.5 ± 5.3, p = 0.003). Success rate (ratio of hit and miss attempts) was significantly higher for experts (novices hit: n = 15; 55.6%; experts hit: n = 19; 83%, p = 0.040). Conclusion: The evaluated training device for distal interlocking of intramedullary nails yielded high scores in terms of training capability and realism. Furthermore, construct validity was proven by reliably discriminating between experts and novices. Participants indicate high further training potential as the device may be easily adapted to other surgical tasks

Intraoperative 3D imaging in intraarticular tibial plateau fractures - Does it help to improve the patients' outcomes?: -

In der vorliegenden Arbeit wird eine retrospektive Fall- Kontroll- Studie präsentiert, welche erstmalig das kurz- bis mittelfristige Outcome komplexer gelenkbeteiligender Tibiakopffrakturen unter Hilfestellung eines additiven intraoperativen 3D Scans im Vergleich zur konventionellen Operation mit einem zweidimensionalen Bildverstärker (Fluoroskopie) untersucht. Hintergrund dieser Arbeit ist, dass komplexe Tibiakopffrakturen eine schwerwiegende Knieverletzung darstellen, welche oft in posttraumatischer Gonarthrose münden. Mit den konventionellen OP- Methoden zeigen sich in der Literatur postoperative Arthroseraten von bis zu 44% und Revisionsraten zwischen 25,3 bis 45,0%. Weiterentwickelte intraoperative bildgebende Verfahren könnten hier möglicherweise zu einem verbesserten klinischen Ergebnis führen. Am Beispiel des intraoperativen 3D- Scans (Ziehm Vision RFD 3D, Fa. Ziehm, Nürnberg, Germany) wurde dies bei Patienten mit einer B3, C1, C2 oder C3- proximalen Tibiafraktur entsprechend der AO- Klassifikation untersucht. Im Zeitraum von Dezember 2015 bis Dezember 2018 wurden am Universitätsklinikum Leipzig, in der Abteilung Orthopädie, Unfallchirurgie und Plastische Chirurgie (überregionales Level 1 Traumazentrum), 22 Patienten mit einer entsprechenden Fraktur unter Einsatz eines intraoperativen 3D- Scans operativ versorgt (3D Gruppe). Die Patienten wurden mit einem postoperativ minimalen zeitlichen Abstand von 12 Monaten radiologisch und mit den Lysholm- und KOOS- Scores nachuntersucht. Entsprechend der Einschlusskriterien konnten 18 Patienten vollständig nachuntersucht werden. Das mittlere Alter der Patienten lag zum Traumazeitpunkt bei 51,0 ± 16,4 Jahren (23–85 Jahre). Entsprechend der AO/OTA- Klassifikation zeigten sich 9x B3, 2x C1, 1x C2 und 6x C3- Frakturen. Der mittlere ASA- Score lag bei 1,44± 0,51. Die mittlere Operationszeit wurde mit 128± 46 min erfasst. Der mittlere Nachuntersuchungszeitpunkt lag bei 20,9± 10,7 Monaten mit den detaillierten Outcome-Scores siehe Tabelle 3 des Manuskripts. In einem definierten Matching- Prozess konnten nachuntersuchte Patienten aus einem historischen Patientenkollektiv, welche in den Jahren 2005 bis 2014 operiert wurden, im Verhältnis 1:1 verglichen werden (2D Gruppe). In diesem Zeitraum stand der intraoperative 3D- Scan am Universitätsklinikum Leipzig noch nicht zur Verfügung. Die Patienten der 2D- Gruppe wurden im Rahmen einer multizentrischen Studie zu Tibiakopffrakturen nachuntersucht, sodass die Outcomedaten zur Verfügung standen und in diese Studie aufgearbeitet einflossen. Aufgrund des Matching- Prozesses sind die Patienten beider Gruppen vergleichbar hinsichtlich Alter, Geschlecht, Frakturmorphologie und dem allgemeinem Gesundheitszustand (ASA- Score). Lediglich der Nachuntersuchungszeitpunkt beider Gruppen variiert signifikant zwischen beiden Gruppen (p< 0,001). Jedoch konnten Studien zeigen, dass Patienten nach operativ versorgten Tibiakopffrakturen im mittelfristigen Nachbeobachtungszeitraum hinsichtlich ihres Outcomes stabil bleiben. Aus diesem Grund ist ein Vergleich der Outcomeparameter beider Gruppen zulässig. Die präsentierte Studie zeigt, dass aufgrund des Einsatzes des intraoperativen 3D- Scans eine intraoperative Revision in beachtlicher Zahl (33,3%) durchgeführt wurde, obwohl die Materiallage und Gelenkstufe zuvor fluoroskopisch akzeptiert wurde. Diese intraoperative Revisionsrate deckt sich mit bestehender Literatur (Mittel 17.2± 6.1%; Intervall 11.7- 26.5%). Durch die intraoperative Revision konnten die klinischen Outcome- Ergebnisse möglicherweise verbessert werden. Sowohl der Lysholm-, als auch der KOOS- Score zeigen für die 3D- Gruppe bessere Ergebnisse. Der KOOS Sport/Rec ist dabei trotz einer geringen Stichprobengröße signifikant besser (p= 0.014) und der KOOS QDL zeigt mathematisch eine Tendenz zugunsten des Einsatzes des 3D- Scan (p= 0,059). Die postoperative Revisionsrate konnte durch den 3D-Scan- Einsatz entgegen der sekundären Hypothese nicht gesenkt werden. Je Gruppe zeigte sich eine postoperative Revisionsrate von 27,8%. Eine höhere postoperative Revisionsrate der 2D- Gruppe konnte möglicherweise nicht erkannt werden, da deutlich mehr Materialentfernungen und Arthrolysen durchgeführt wurden, als in der 3D- Gruppe (10:1). Diese Materialentfernungen sind nach 16.9± 2.6 Monaten erfolgt. Da zum Zeitpunkt der Studie einige Patienten der 3D- Gruppe diesen Zeitpunkt der Nachuntersuchung noch nicht überschritten hatten, ist ein abschließender Vergleich nicht zulässig. Entsprechende Kontroll- CT- Bildgebungen, welche die Materiallage vor Entfernung zeigten, wurden aufgrund der zusätzlichen Strahlenbelastung bei nachgewiesener Frakturkonsolidierung im Röntgen unterlassen. Die Operationsdauer der 3D Gruppe zeigte sich im Mittel um ungefähr 12 min im Vergleich zur 2D Gruppe verlängert (p=0,28). Eine erhöhte postoperative Infektionsrate ergab sich aus der verlängerten OP-Dauer nicht. Je Gruppe zeigte sich im Bereich des einliegenden Osteosynthesematerials eine postoperative Infektion. Aufgrund des retrospektiven Studiendesigns bestehen in der präsentierten Arbeit einige Limitationen. Die Informationen bezüglich operativer Revisionen, OP- Dauer, verwendeter Implantate, Bildqualität und besonderer operativer Umstände wurde aus den medizinischen Datenbanken und nicht prospektiv erfasst. Der Nachuntersuchungszeitraum ist zwischen beiden Gruppen signifikant unterschiedlich. Ein Selektionsbias zwischen 3D- und 2D- Gruppe kann trotz gleicher Implantate, Operateure und postoperativer Standards nicht sicher ausgeschlossen werden. Aus diesen Gründen wären weitere prospektive Studien wünschenswert. Zusammenfassend konnte in der vorliegenden Arbeit gezeigt werden, dass der Einsatz eines intraoperativen 3D- Scan bei der operativen Versorgung der komplexen gelenkbeteiligenden Tibiafraktur das mittelfristige Outcome hinsichtlich des KOOS Sport/Rec verbessert (p=0,014). Ebenso konnte gezeigt werden, dass der 3D- Scan zu einer relevanten Anzahl intraoperativer Revisionen (33,3%) führte. Die Rate an postoperativen Revisionen konnte durch Anwenden des intraoperativen 3D- Scan nicht gesenkt werden.  :1. Einführung 1.1 Die proximale Tibiafraktur- Epidemiologie und Klassifikation 1.2 Operatives Vorgehen 1.3 Intraoperative Fraktur darstellende Verfahren 1.4 Nachbehandlung und Outcomemessung 1.5 Ziele der Arbeit 2. Publikationsmanuskript 3. Zusammenfassung und Ausblick 4. Literaturverzeichnis 5. Anlagen 5.1 Verzeichnis der verwendeten Abkürzungen und Symbole 5.2 Abbildungsverzeichnis 5.3 Erklärung über den wissenschaftlichen Beitrag des Promovenden zur Arbeit 5.4 Erklärung über die eigenständige Anfertigung der Arbeit 5.5 Curriculum vitae 5.6 Danksagun

Intraoperative 3D imaging in intraarticular tibial plateau fractures - Does it help to improve the patients’ outcomes?

Background!#!In tibial plateau fractures (TPF) the restoration of an anatomical joint surface as well as an exact subchondral screw position for postoperative stability is crucial for the outcome. The aim of this study was to determine whether the additional use of an intraoperative 3D imaging intensifier (3D) might help to improve the outcome of complex TPF.!##!Methods!#!We performed a retrospective case-control study of a level 1 trauma center. Patients with AO/OTA 41 B3 and C-TPF operated on using a 3D imaging intensifier between November 2015 and December 2018 (3D group) were included. The outcomes of this patients were compared to patients operated without 3D imaging between January 2005 to December 2014 (2D group). The comparison of the groups was performed by matched pair analysis. The functional outcome of both groups was measured by KOOS and Lysholm Score after a follow-up period of at least 12 months. Operation time, infections and postoperative revisions were registered.!##!Results!#!In total, 18 patients were included in the 3D group (mean age: 51.0± 16.4 years; 12 females) and an equal number of matching partners from the 2D group (mean age: 50.3± 15.2 years; 11 females) were found (p=0.82; p=0.79). We found 9x B3, 2x C1, 1x C2, 6x C3 fractures according to AO/OTA for each group (p=1.00) with comparable ASA score (p=0.27). The mean operation time was 127.9± 45.9 min and 116.1± 45.7 min for the 3D and 2D group (p=0.28). The mean follow-up time was 20.9± 10.7 months for the 3D and 55.5± 34.7 months for the 2D group (p&amp;lt; 0.001). For the 3D group a mean Lysholm overall score of 67.4± 26.8 and KOOS overall score of 72.6± 23.5 could be assessed. In contrast, a mean Lysholm overall score of 62.0± 21.4 and KOOS overall score of 65.8± 21.6 could be measured in the 2D group (p=0.39; p=0.31). Thereby, functional outcome of the 3D group showed a significant higher KOOS Sport/Rec sub score of 54.7± 35.0 in comparison to the 2D group with 26.7± 31.6 (p= 0.01). Postoperative revisions had to be performed in 27.8% of cases in both groups (p=1.00). Due to the 3D imaging an intraoperative revision was performed in 33.3% (6/18).!##!Conclusion!#!In our study we could show that re-reduction of the fracture or implant re-positioning were performed in relevant numbers based on the 3D imaging. This was associated with a midterm clinical benefit in regard to better KOOS Sport/Rec scores.!##!Trial registration!#!AZ 488 /20-ek

Combined Humeral Head and Shaft Fractures: Outcome Following Intramedullary Nailing and Plating

Background and Objectives: Combined fractures of the humeral head and shaft (FHS) are rare but frequently involve an intermuscular fracture as its characteristic pattern. The aim of this retrospective study was to investigate intramedullary nailed and plated FHS in terms of outcomes and complications. Materials and Methods: The present study included patients with FHS, treated via either intramedullary nailing or plating within a period of 10 years, with a minimum follow-up of 12 months. Functional outcome was assessed using the age- and sex-adapted Constant–Murley Score (CMS-K). Rates of complications and revision surgeries were registered. Results: Twenty-five patients (18 females, 7 males, age 60.1 ± 14.2 years, range 23–76 years) were included in the study. Nailing was performed in 16 patients (12 females, 4 males, age 62.6 ± 12.4 years), whereas plating was executed in nine patients (6 females, 3 males, age 55.8 ± 17.0 years). Follow-up among all patients was 45.1 ± 26.3 months (range 12–97 months). CMS-K was 70.3 ± 32.3 in the nailing group, with reoperation in four cases, and 76.0 ± 31.0 in the plating group, with one reoperation (p = 0.42). Patients with no metaphyseal fragment displacement (n = 19; CMS-K 76.7 ± 17.3) demonstrated significantly better functional outcomes versus those with secondary displacement of the metaphyseal fragments (n = 6; CMS-K 60.0 ± 17.1), p = 0.046. Conclusions: Comparable acceptable clinical outcome is obtained when comparing nailing with additional open cerclage or lag-screw fixation techniques versus plating with open reduction. However, a higher revision rate was observed after nailing. The correct metaphyseal fragment fixation seems to be crucial to avoid loss of reduction and hence the need for revision surgery, as well as a worse outcome

Validity of a Novel Digitally Enhanced Skills Training Station for Freehand Distal Interlocking

Background and Objectives: Freehand distal interlocking of intramedullary nails is technically demanding and prone to handling issues. It requires precise placement of a screw through the nail under fluoroscopy guidance and can result in a time consuming and radiation expensive procedure. Dedicated training could help overcome these problems. The aim of this study was to assess construct and face validity of new Digitally Enhanced Hands-On Surgical Training (DEHST) concept and device for training of distal interlocking of intramedullary nails. Materials and Methods: Twenty-nine novices and twenty-four expert surgeons performed interlocking on a DEHST device. Construct validity was evaluated by comparing captured performance metrics—number of X-rays, nail hole roundness, drill tip position and drill hole accuracy—between experts and novices. Face validity was evaluated with a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale. Results: Face validity: mean realism of the training device was rated 6.3 (range 4–7). Training potential and need for distal interlocking training were both rated with a mean of 6.5 (range 5–7), with no significant differences between experts and novices, p 0.234. All participants (100%) stated that the device is useful for procedural training of distal nail interlocking, 96% wanted to have it at their institution and 98% would recommend it to colleagues. Construct validity: total number of X-rays was significantly higher for novices (20.9 6.4 versus 15.5 5.3, p = 0.003). Success rate (ratio of hit and miss attempts) was significantly higher for experts (novices hit: n = 15; 55.6%; experts hit: n = 19; 83%, p = 0.040). Conclusion: The evaluated training device for distal interlocking of intramedullary nails yielded high scores in terms of training capability and realism. Furthermore, construct validity was proven by reliably discriminating between experts and novices. Participants indicate high further training potential as the device may be easily adapted to other surgical tasks

Suture button versus syndesmotic screw in ankle fractures - evaluation with 3D imaging-based measurements

Background!#!Inadequate reduction of syndesmotic injuries can result in disabling clinical outcomes. The aim of the study was to compare syndesmosis congruity after fixation by syndesmotic screws (SYS) or a suture button system (SBS) using three-dimensional (3D) computed imaging techniques.!##!Methods!#!In a retrospective single-center study, patients with unilateral stabilization of an ankle fracture with a syndesmotic injury and post-operative bilateral CT scans were analyzed using a recently established 3D method. The side-to-side differences were compared for tibio-fibular clear space (∆CS), translation angle (∆α), and vertical offset (∆z) among patients stabilized with syndesmotic screws or suture button system. Syndesmotic malreduction was defined for ∆CS &amp;gt; 2 mm and for |∆α| &amp;gt; 5°. ∆CS and ∆α were correlated with two-dimensional (2D) measurements.!##!Results!#!Eighteen patients stabilized with a syndesmosis screw and 29 stabilized with a suture button system were analyzed. After stabilization, both groups revealed mild diastasis (SYS: mean ∆CS 0.3 mm, SD 1.1 mm vs SBS: mean ∆CS 0.2 mm, SD 1.2 mm, p = 0.710). In addition, both stabilization methods showed slight dorsalization of the fibula (SYS: mean ∆α 0.5°, SD 4.6° vs SBS: mean ∆α 2.1°, SD 3.7°, p = 0.192). Also, restoration of the fibula-to-tibia length ratio also did not differ between the two groups (SYS: mean Δz of 0.5 mm, SD 2.4 mm vs SBS: mean Δz of 0 mm, SD 1.2 mm; p = 0.477). Malreduction according to high ∆α was most common (26% of cases), with equal distribution between the groups (p = 0.234). ∆CS and ∆α showed good correlation with 2D measurements (ρ = 0.567; ρ = 0.671).!##!Conclusion!#!This in vivo analysis of post-operative 3D models showed no differences in immediate post-operative alignment after syndesmotic screws or suture button system. Special attention should be paid to syndesmotic malreduction in the sagittal orientation of the fibula in relation to the tibia in radiological control of the syndesmotic congruity as well as intra-operatively

Validity of a Novel Digitally Enhanced Skills Training Station for Freehand Distal Interlocking

Background and Objectives: Freehand distal interlocking of intramedullary nails is technically demanding and prone to handling issues. It requires precise placement of a screw through the nail under fluoroscopy guidance and can result in a time consuming and radiation expensive procedure. Dedicated training could help overcome these problems. The aim of this study was to assess construct and face validity of new Digitally Enhanced Hands-On Surgical Training (DEHST) concept and device for training of distal interlocking of intramedullary nails. Materials and Methods: Twenty-nine novices and twenty-four expert surgeons performed interlocking on a DEHST device. Construct validity was evaluated by comparing captured performance metrics—number of X-rays, nail hole roundness, drill tip position and drill hole accuracy—between experts and novices. Face validity was evaluated with a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale. Results: Face validity: mean realism of the training device was rated 6.3 (range 4–7). Training potential and need for distal interlocking training were both rated with a mean of 6.5 (range 5–7), with no significant differences between experts and novices, p 0.234. All participants (100%) stated that the device is useful for procedural training of distal nail interlocking, 96% wanted to have it at their institution and 98% would recommend it to colleagues. Construct validity: total number of X-rays was significantly higher for novices (20.9 6.4 versus 15.5 5.3, p = 0.003). Success rate (ratio of hit and miss attempts) was significantly higher for experts (novices hit: n = 15; 55.6%; experts hit: n = 19; 83%, p = 0.040). Conclusion: The evaluated training device for distal interlocking of intramedullary nails yielded high scores in terms of training capability and realism. Furthermore, construct validity was proven by reliably discriminating between experts and novices. Participants indicate high further training potential as the device may be easily adapted to other surgical tasks

Impact of Anterior Malposition and Bone Cement Augmentation on the Fixation Strength of Cephalic Intramedullary Nail Head Elements

Background and Objectives: Intramedullary nailing of trochanteric fractures can be challenging and sometimes the clinical situation does not allow perfect implant positioning. The aim of this study was (1) to compare in human cadaveric femoral heads the biomechanical competence of two recently launched cephalic implants inserted in either an ideal (centre&ndash;centre) or less-ideal anterior off-centre position, and (2) to investigate the effect of bone cement augmentation on their fixation strength in the less-ideal position. Materials and Methods: Fourty-two paired human cadaveric femoral heads were assigned for pairwise implantation using either a TFNA helical blade or a TFNA screw as head element, implanted in either centre&ndash;centre or 7 mm anterior off-centre position. Next, seven paired specimens implanted in the off-centre position were augmented with bone cement. As a result, six study groups were created as follows: group 1 with a centre&ndash;centre positioned helical blade, paired with group 2 featuring a centre&ndash;centre screw, group 3 with an off-centre positioned helical blade, paired with group 4 featuring an off-centre screw, and group 5 with an off-centre positioned augmented helical blade, paired with group 6 featuring an off-centre augmented screw. All specimens were tested until failure under progressively increasing cyclic loading. Results: Stiffness was not significantly different among the study groups (p = 0.388). Varus deformation was significantly higher in group 4 versus group 6 (p = 0.026). Femoral head rotation was significantly higher in group 4 versus group 3 (p = 0.034), significantly lower in group 2 versus group 4 (p = 0.005), and significantly higher in group 4 versus group 6 (p = 0.007). Cycles to clinically relevant failure were 14,919 &plusmn; 4763 in group 1, 10,824 &plusmn; 5396 in group 2, 10,900 &plusmn; 3285 in group 3, 1382 &plusmn; 2701 in group 4, 25,811 &plusmn; 19,107 in group 5 and 17,817 &plusmn; 11,924 in group 6. Significantly higher number of cycles to failure were indicated for group 1 versus group 2 (p = 0.021), group 3 versus group 4 (p = 0.007), and in group 6 versus group 4 (p = 0.010). Conclusions: From a biomechanical perspective, proper centre&ndash;centre implant positioning in the femoral head is of utmost importance. In cases when this is not achievable in a clinical setting, a helical blade is more forgiving in the less ideal (anterior) malposition when compared to a screw, the latter revealing unacceptable low resistance to femoral head rotation and early failure. Cement augmentation of both off-centre implanted helical blade and screw head elements increases their resistance against failure; however, this effect might be redundant for helical blades and is highly unpredictable for screws

NEW GENERATION OF SUPERIOR SINGLE PLATING VS LOW-PROFILE DUAL MINI-FRAGMENT PLATING IN DIAPHYSEAL CLAVICLE FRACTURES. A BIOMECHANICAL COMPARATIVE STUDY.

BACKGROUND Recently, a new generation of superior clavicle plates was developed featuring the variable angle locking technology for enhanced screw positioning and a less prominent and optimized plate-to-bone fit design. On the other hand, mini-fragment plates in dual plating mode have demonstrated promising clinical results. The aim of the current study was to compare the biomechanical competence of single superior plating using the new generation plate versus dual plating using low-profile mini-fragment plates. \ud METHODS Sixteen paired human cadaveric clavicles were pairwise assigned to two groups for instrumentation with either a superior 2.7 mm Variable Angle Locking Compression Plate (Group 1), or with one 2.5 mm anterior combined with one 2.0 mm superior matrix mandible plate (Group 2). An unstable clavicle shaft fracture (AO/OTA 15.2C) was simulated by means of a 5mm osteotomy gap. Specimens were cyclically tested to failure under craniocaudal cantilever bending, superimposed with bidirectional torsion around the shaft axis and monitored via motion tracking. RESULTS Initial construct stiffness was significantly higher in Group 2 (9.28 ± 4.40 N/mm) compared to Group 1 (3.68 ± 1.08 N/mm), p=0.003. The amplitudes of interfragmentary motions in terms of axial and shear displacement, fracture gap opening and torsion, over the course of 12,500 cycles were significantly higher in Group 1 compared to Group 2, p≤0.038. Cycles to 2mm shear displacement were significantly lower in Group 1 (22792 ± 4346) compared to Group 2 (27437 ± 1877), p=0.047. CONCLUSION From a biomechanical perspective, low-profile 2.5/2.0 dual plates can be considered as a useful alternative for diaphyseal clavicle fracture fixation especially in less common unstable fracture configurations. 2.7 single superior variable angle locking plates and can therefore be considered as a useful alternative for diaphyseal clavicle fracture fixation especially in less common unstable fracture configurations

Medial helical versus straight lateral plating of distal femoral fractures-a biomechanical comparative study

BACKGROUND: Distal femoral fractures are commonly treated with lateral straight plates. However, the lateral approach may not always be desirable, and 180°-helical plates may be an alternative. AIM: To investigate the biomechanical competence of 180°-helical plating versus standard straight lateral plating of unstable fractures at the distal femur. METHODS: Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate-Distal Femur, using either 180°-helical plates (group 1) or conventional straight lateral plates (group 2). An unstable distal femoral fracture AO/OTA 33-A3.3 was simulated. All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading in internal rotation until failure. FINDINGS: Initial axial stiffness (N/mm) was significantly higher in group 1 (185.6 ± 50.1) compared to group 2 (56.0 ± 14.4), p < 0.001. Group 1 demonstrated significantly higher initial interfragmentary flexion (°) and significantly lower initial varus/valgus deformation (°) under 500 N static axial compression versus group 2 (2.76 ± 1.02 versus 0.87 ± 0.77 and 4.08 ± 1.49 versus 6.60 ± 0.47), p ≤ 0.005. Shear displacement (mm) under 6 Nm static torsion was significantly higher in group 1 versus group 2 in both internal (1.23 ± 0.28 versus 0.40 ± 0.42) and external (1.21 ± 0.40 versus 0.57 ± 0.33) rotation, p ≤ 0.013. Cycles to failure and failure load (N) (clinical/catastrophic) were significantly higher in group 1 (12,484 ± 2116/13,752 ± 1518 and 1748.4 ± 211.6/1875.2 ± 151.8) compared to group 2 (7853 ± 1262/9727 ± 836 and 1285.3 ± 126.2/1472.7 ± 83.6), p ≤ 0.001. INTERPRETATION: Although 180°-helical plating using a pre-contoured standard straight lateral plate was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, the helical plates were associated with significantly higher endurance to failure. From a biomechanical perspective, 180°-helical plating may be considered as a valuable alternative to standard straight lateral plating of unstable distal femoral fractures