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"Pastor, Torsten"
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Anterior variable-angle locked plating versus tension band wiring of simple and complex patella fractures – a biomechanical investigation
by
Saura-Sanchez, Eladio
,
Zderic, Ivan
,
Woodburn, William
in
Analysis
,
Anterior variable-angle locked plating
,
Biomechanical Phenomena
2023
Background
The aim of this study was to investigate the biomechanical performance of novel anterior variable-angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.
Methods
Sixteen pairs of human cadaveric knees were used to simulate two-part simple transverse AO/OTA 34-C1 and five-part complex AO/OTA 34-C3 patella fractures. The complex fracture pattern was characterized with a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral and an inferior fragment mimicking comminution around the distal patella pole. Eight pairs with simple fractures were split for fixation via either tension band wiring (TBW) through two parallel cannulated screws or anterior variable-angle locked plating, whereas other eight pairs with complex fractures were split for either TBW through two parallel cannulated screws plus circumferential cerclage wiring, or anterior variable-angle locked plating using a cortical caudo-cranial polar screw. Each specimen was tested over 5000 cycles with a range of motion from 90° flexion to full extension by pulling on the quadriceps tendon. Interfragmentary movements were captured by motion tracking.
Results
For both fracture types, the longitudinal and shear articular displacements, measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following anterior variable-angle locked plating versus TBW, p ≤ 0.01.
Conclusions
From a biomechanical perspective, anterior locked plating of both simple and complex patella fractures resulted in less interfragmentary displacement under extended cyclic loading.
Journal Article
Three-Dimensional Planning and Patient-Specific Instrumentation for the Fixation of Distal Radius Fractures
2022
Background and Objectives: Three-dimensional planning and guided osteotomy utilizing patient-specific instrumentation (PSI) with the contralateral side used as a reference have been proven as effective in the treatment of malunions following complex fractures of the distal radius. However, this approach has not yet been described in relation to fracture reduction of the distal radius. The aim of this study was to assess the technical and logistical feasibility of computer-assisted surgery in a clinical setting using PSI for fracture reduction and fixation. Materials and Methods: Five patients with varied fracture patterns of the distal radius underwent operative treatment with using PSI. The first applied PSI guide allowed specific and accurate placement of Kirschner wires inside the multiple fragments, with subsequent concurrent reduction using a second guide. Results: Planning, printing of the guides, and operations were performed within 5.6 days on average (range of 1–10 days). All patients could be treated within a reasonable period of time, demonstrating good outcomes, and were able to return to work after a follow-up of three months. Mean wrist movements (°) were 58 (standard deviation (SD) 21) in flexion, 62 (SD 15) in extension, 73 (SD 4) in pronation and 74 (SD 10) in supination at a minimum follow-up of 6 months. Conclusions: Three-dimensional planned osteosynthesis using PSI for treatment of distal radius fractures is feasible and facilitates reduction of multiple fracture fragments. However, higher costs must be taken into consideration for this treatment.
Journal Article
Osteophyte Growth Over 10 Years in the Fingers of High‐Level Climbers and Contributing Factors
2026
Although osteophytes in climbers' fingers are known as part of a mechano‐adaption, the progression of osteophytes and contributing factors during an advanced elite climber's career is still unknown. This study analyzes osteophyte growth over 10 years for each phalangeal head and base of all proximal and distal interphalangeal joints (PIP and DIP) individually as well as the impact of potential climbing related influencing factors. Furthermore, the osteophytes located at the palmar neck of the proximal phalanx (palmar neck osteophytes) were investigated separately and joint space narrowing was evaluated and compared with osteophyte growth. Radiographs of 31 male elite climbers were analyzed in lateral view for osteophytes and in anterior–posterior (a.p.) view for joint space at baseline and 10‐year follow‐up. Even after more than 2 decades of elite climbing, osteophytes grew significantly at most phalangeal heads and bases. Already severely affected joints at baseline, specifically DIP Dig III and IV of both hands, had an especially high effect size (DIP base: Dig III: left; 0.517, right; 0.355, Dig IV: left; 0.519, right; 0.555, DIP head: Dig III: left; 0.348, right; 0.591, Dig IV: left; 0.533, right; 0.408). The extent of osteophytes at baseline is highly predictive for further development (79.3%); however, no climbing‐related factors were determinable for additional explanation. Palmar neck osteophytes are pathognomonic to climbing as they are most likely caused by the phalangeal base hitting this area repeatedly in a hyperflexed position. Furthermore, there is no correlation between osteophyte growth and joint space narrowing during an elite climber's career. Highlights Even after 20 years or more of high‐level climbing, a significant osteophyte growth over the last 10 years can be observed at almost all phalangeal heads and bases. The extent of osteophytes at baseline is highly predictive for further development; however, no climbing related factor could be identified to explain the vast differences between the climbers. Osteophytes located at the palmar neck of the proximal phalanx are pathognomonic to climbing as they are most likely caused by the phalangeal base hitting this area in an hyperflexed position.
Journal Article
Biomechanical analysis of recently released cephalomedullary nails for trochanteric femoral fracture fixation in a human cadaveric model
by
Gehweiler, Dominic
,
Knobe, Matthias
,
Zderic, Ivan
in
Biomechanics
,
Fractures
,
Polymethyl methacrylate
2022
BackgroundRecently, two novel concepts for intramedullary nailing of trochanteric fractures using a helical blade or interlocking dual screws have demonstrated advantages as compared to standard single-screw systems. However, these two concepts have not been subjected to a direct biomechanical comparison so far. The aims of this study were to investigate in a human cadaveric model with low bone quality (1) the biomechanical competence of nailing with the use of a helical blade versus interlocking screws, and (2) the effect of cement augmentation on the fixation strength of the helical blade.MethodsTwelve osteoporotic and osteopenic human cadaveric femoral pairs were assigned for pairwise implantation using either a short TFN-ADVANCED Proximal Femoral Nailing System (TFNA) with a helical blade head element or a short TRIGEN INTERTAN Intertrochanteric Antegrade Nail (InterTAN) with interlocking screws. Six osteoporotic femora, implanted with TFNA, were augmented with bone cement. Four groups were created: group 1 (TFNA) paired with group 2 (InterTAN), both consisting of osteopenic specimens, and group 3 (TFNA augmented) paired with group 4 (InterTAN), both consisting of osteoporotic specimens. An unstable trochanteric AO/OTA 31-A2.2 fracture was simulated and all specimens were tested until failure under progressively increasing cyclic loading.ResultsStiffness in group 3 was significantly higher versus group 4, p = 0.03. Varus (°) and femoral head rotation around the femoral neck axis (°) after 10,000 cycles were 1.9 ± 1.0/0.3 ± 0.2 in group 1, 2.2 ± 0.7/0.7 ± 0.4 in group 2, 1.5 ± 1.3/0.3 ± 0.2 in group 3 and 3.5 ± 2.8/0.9 ± 0.6 in group 4, being significantly different between groups 3 and 4, p = 0.04. Cycles to failure and failure load (N) at 5° varus or 10° femoral head rotation around the neck axis in groups 1–4 were 21,428 ± 6020/1571.4 ± 301.0, 20,611 ± 7453/1530.6 ± 372.7, 21,739 ± 4248/1587.0 ± 212.4 and 18,622 ± 6733/1431.1 ± 336.7, being significantly different between groups 3 and 4, p = 0.04.ConclusionsNailing of trochanteric femoral fractures with use of helical blades is comparable to interlocking dual screws fixation in femoral head fragments with low bone quality. Bone cement augmentation of helical blades provides significantly greater fixation strength compared to interlocking screws constructs.
Journal Article
Antegrade anterior column acetabulum fracture fixation with cannulated compression headless screws—A biomechanical study on standardized osteoporotic artificial bone
by
Hierholzer, Christian
,
Zderic, Ivan
,
Pastor, Torsten
in
Acetabulum
,
Acetabulum - injuries
,
Acetabulum - surgery
2024
Due to the increase in life expectancy and high-energy traumas, anterior column acetabular fractures (ACFs) are also increasing. While open reduction and internal fixation (ORIF) is still the standard surgical procedure, minimally invasive, percutaneous fixation of osteoporotic acetabulum fractures (AF) are growing in popularity. The aim of this biomechanical study was to evaluate the biomechanical competence following antegrade fixation with a standard screw versus a cannulated compression headless screw.
Eight anatomical osteoporotic composite pelvises were given an anterior column fracture. Two groups of eight specimens each (n = 8) for fixation with either a 6.5 mm cannulated compression headless screw in group Anterior Acetabulum Canulated Compression Headless Screw (AACCH), or with a 6.5 mm partially threaded cannulated screw in group Anterior Acetabulum Standard Screw (AASS) where compared. Each specimen was biomechanically loaded cyclically at a rate of 2 Hz with monotonically increasing compressive load until failure. Motions were assessed by means of optical motion tracking.
Initial construct stiffness trended higher in group AACCH at 152.4 ± 23.1 N/mm compared to group AASS at 118.5 ± 34.3 N/mm, p = 0.051. Numbers of cycles and corresponding peak load at failure, were significantly higher in group AACCH at 6734 ± 1669 cycles and 873.4 ± 166.9 N versus group AASS at 4440 ± 2063 cycles and 644.0 ± 206.3 N, p = 0.041. Failure modes were breakout of the screws around the proximal entry point.
From a biomechanical perspective, group AACCH was associated with superior biomechanical competence compared to standard partially threaded cannulated screws and could therefore be considered as valid alternative for fixation of anterior acetabulum fractures.
Journal Article
Selective versus non-selective NSAIDs as prophylaxis for heterotopic ossification following hip arthroplasty: a meta-analysis
by
Maffulli, Nicola
,
Pintore, Andrea
,
Migliorini, Filippo
in
Anti-inflammatory agents
,
Biomedical materials
,
Disease prevention
2022
BackgroundSome patients have demonstrated evidence of heterotopic ossification (HO) following total hip arthroplasty (THA). Selective and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) are used as prophylaxis for HO following THA. This meta-analysis compared selective versus non-selective NSAIDs as prophylaxis for HO following THA.Material and methodsThe present study was conducted according to the PRISMA 2020 guidelines. All the clinical investigations comparing selective versus non-selective NSAIDs as prophylaxis for HO following THA were accessed in February 2022. An assessment of the methodological quality and statistical analyses were performed through the risk of bias summary tool of the Review Manager 5.3 software (Cochrane Collaboration, Copenhagen). The modified Brooker staging system was used to rate the efficacies of the interventions.ResultsData from 8 studies and 1526 patients were collected. 60.8% were female. No difference was found in the sample size, mean age, and percentage of females between the two groups at baseline. No statistically significant difference was found between selective and non-selective NSAIDs in term of efficacy. 72% (1078 of 1502) of the patients were classified as Brooker 0, 21% (322 of 1502) as Brooker I, 5% (80 of 1502) as Brooker II, 1% (16 of 1502) as Brooker III, and 0.1% (2 of 1502) as Brooker IV.ConclusionSelective and non-selective NSAIDs were equally effective when used as prophylaxis for HO following THA.Level of evidenceLevel III, systematic review and meta-analysis.
Journal Article
Lower oxygen saturation with higher rates of norepinephrine in bone fractures of polytrauma patients: a pilot study
by
Knobe, Matthias
,
Koch, Laura
,
Laschke, Matthias W.
in
Blood pressure
,
Care and treatment
,
Catecholamines
2023
In a pilot trial, we used the laser-Doppler device ‘Oxygen to see’ (O2C, LEA Medizintechnik, Winchesterstr. 2, D-35394 Gießen, Germany) to measure SO2, haemoglobin (Hb), and blood flow (BF) in 3, 10, and 14/16 mm depth in four tibial and clavicle fractures of three patients with multiple injuries who received NE. In 3 mm, up to 14.7% of the variability could be explained by MAP alone, and in 14/16 mm, up to 13.5% by NE alone. [...]only NE and not MAP had an effect on SO2 in 14/16 mm depth inside the fractures. Effect of early use of noradrenaline on in-hospital mortality in haemorrhagic shock after major trauma: a propensity-score analysis.
Journal Article
Optimizing Subtalar Arthrodesis: A Human Cadaveric Evaluation of a Novel Partially-Threaded Screw Combination in the Delta Configuration
2024
Background and Objectives: Despite the established role of subtalar joint arthrodesis (SJA) for treatment of subtalar osteoarthritis, achieving bone union remains challenging, with up to 46% non-union rates. Adequate compression and stable fixation are crucial for successful outcomes, with internal screw fixation being the gold standard for SJA. The delta configuration, featuring highly divergent screws, offers stability, however, it can result in hardware irritation in 20–30% of patients. Solutions to solve this complication include cannulated compression screw (CCS) countersinking or cannulated compression headless screw (CCHS) application. The aim of this biomechanical study was to investigate the stability of a delta configuration for SJA utilizing either a combination of a posterior CCHS and an anterior CCS or a standard two-CCS combination. Materials and Methods: Twelve paired human cadaveric lower legs were assigned pairwise to two groups for SJA using either two CCSs (Group 1) or one posterior CCHS and one anterior CCS (Group 2). All specimens were tested under progressively increasing cyclic loading to failure, with monitoring of the talocalcaneal movements via motion tracking. Results: Initial stiffness did not differ significantly between the groups, p = 0.949. Talocalcaneal movements in terms of varus–valgus deformation and internal–external rotation were significantly bigger in Group 1 versus Group 2, p ≤ 0.026. Number of cycles until reaching 5° varus–valgus deformation was significantly higher in Group 2 versus Group 1, p = 0.029. Conclusions: A delta-configuration SJA utilizing a posterior CCHS and an anterior CCS is biomechanically superior versus a standard configuration with two CCSs. Clinically, the use of a posterior CCHS could prevent protrusion of the hardware in the heel, while an anterior CCS could facilitate less surgical time and thus less complication rates.
Journal Article
Quality of Life and Working Conditions of Hand Surgeons—A National Survey
by
Deml, Michael J.
,
Pastor, Tatjana
,
Vögelin, Esther
in
Burn out (Psychology)
,
Burnout
,
Careers
2023
Background and Objectives: Providing high-quality care for patients in hand surgery is an everyday endeavor. However, the quality of life (QoL) and working conditions of hand surgeons ensuring these high-quality services need to be investigated. The aim of this study was to evaluate the QoL and working conditions of Swiss hand surgeons. Materials and Methods: A national survey with Swiss hand surgeons was conducted. Standardized questionnaires were completed anonymously online. Core topics included working conditions, QoL, satisfaction with the profession, and aspects of private life. Results: A total of 250 hand surgeons were invited to participate, of which 110 (44.0%) completed the questionnaire. Among all participants, 43.6% stated that they are on call 4–7 days per month, versus 8.2% never being on call. Overall, 84.0% of the residents, 50.0% of the senior physicians, 27.6% of the physicians in leading positions, and 40.6% of the senior consultants/practice owners, as well as 55.1% of the female and 44.3% of the male respondents, felt stressed by their job, even during holidays and leisure time. Out of all participants, 85.4% felt that work affects private relationships negatively. Despite the reported stress, 89.1% would choose hand surgery as a profession again. Less on-call duty (29.1%) and better pay (26.4%) are the most prioritized factors for attractiveness of a position at a hospital. Conclusions: The QoL of Swiss hand surgeons is negatively affected by their workload and working hours. Residents, senior physicians and female surgeons suffer significantly more often from depression, burnout or chronic fatigue in comparison to leading positions, senior consultants/practice owners and male surgeons. Better pay or less on-call duty would make the work more attractive in acute care hospitals.
Journal Article
Relative lateral wall thickness is an improved predictor for postoperative lateral wall fracture after trochanteric femoral fracture osteosynthesis
2023
Lateral wall thickness is a known predictor for postoperative stability of trochanteric femoral fractures and occurrence of secondary lateral wall fractures. Currently, the AO/OTA classification relies on the absolute lateral wall thickness (aLWT) to distinguish between stable A1.3 and unstable A2.1 fractures that does not take interpersonal patient differences into account. Thus, a more individualized and accurate measure would be favorable. Therefore, we proposed and validated a new patient-specific measure—the relative lateral wall thickness (rLWT)—to consider individualized measures and hypothesized its higher sensitivity and specificity compared with aLWT. First, in 146 pelvic radiographs of patients without a trochanteric femoral fracture, the symmetry of both caput-collum-diaphyseal angle (CCD) and total trochanteric thickness (TTT) was assessed to determine whether the contralateral side can be used for rLWT determination. Then, data of 202 patients were re-evaluated to compare rLWT versus previously published aLWT. Bilateral symmetry was found for both CCD and TTT (p ≥ 0.827), implying that bone morphology and geometry of the contralateral intact side could be used to calculate rLWT. Validation revealed increased accuracy of the rLWT compared with the gold standard aLWT, with increased specificity by 3.5% (Number Needed to Treat = 64 patients) and sensitivity by 1% (Number Needed to Treat = 75 patients). The novel rLWT is a more accurate and individualized predictor of secondary lateral wall fractures compared with the standard aLWT. This study established the threshold of 50.5% rLWT as a reference value for predicting fracture stability in trochanteric femoral fractures.
Journal Article