E-scooter accidents-epidemiology and injury patterns: 3-year results from a level 1 trauma center in Germany.

INTRODUCTION: Since the introduction of e-scooters in Germany in 2019, they are becoming more and more popular and associated injuries have increased significantly. The aim of this study was to assess the injury patterns after e-scooter accidents. MATERIALS AND METHODS: From May 2019 to October 2022, all consecutive patients who presented at our emergency department (ED) following e-scooter accidents were included in our study and retrospectively analyzed. RESULTS: A total of 271 patients were included in our study. The mean age was 33 years. 38% of the patients were female and 62% were male. Most common injuries were traumatic brain injuries in 38% of the patients together with fractures affecting the upper limb (17%). An operative treatment was necessary in 40 patients. Most of the patients presented at night and about 30% were under the influence of alcohol. CONCLUSIONS: Our study shows one of the largest cohort of patients suffering e-scooter accidents in Europe. Compulsory helmet use, stricter alcohol controls and locking periods could contribute significantly to safety.

Uncemented hip revision cup as an alternative for T-type acetabular fractures: A cadaveric study.

BACKGROUND: The current rise in elderly patients with compromised bone quality complicates the surgical treatment of acetabular T-type fractures (AO type 62B2 fractures). There is on ongoing discussion about the treatment options, mostly consisting of an open reduction and internal fixation (ORIF) with or without primary or secondary total hip arthroplasty (THA). Yet, these patients are oftentimes unable to fulfil weight-bearing restrictions and mostly present with an unavailability of a stable anchor site. Consequently, this study investigates the feasibility of a cementless hip revision cup for acetabular T-type fractures and compares its biomechanical properties to ORIF. HYPOTHESIS: The cementless hip revision cup provides sufficient biomechanical stability under the simulation of full weight-bearing. PATIENTS AND METHODS: The study compared two groups of human cadaveric hip bones with T-type fractures, of whom 6 subjects were treated with ORIF (6 male; mean age: 62±17years; mean body weight: 75±15) versus 6 subjects treated with a cementless hip revision cup (2 male; 69±12 years; 73±15kg). The group-assignment was controlled for comparable BMD results (mean BMD: ORIF 110±37 mg Ca-Ha/mL versus hip revision cup 134±32 mg Ca-Ha/mL). To compare for biomechanical stability cyclic loading was applied measuring the force and dislocation of the fracture gap at standardized bone loci using an all-electric testing machine and a 3D-ultrasound measuring system. RESULTS: Comparing superior pubic ramus versus iliac wing (cementless hip revision cup versus ORIF [mean±standard deviation]: 5.8±2.0 versus 7.0±3.2; p=0.032) as well as sacral ala versus iliac wing (4.6±2.2 versus 6.4±3.7; p=0.002), the cementless revision cup achieved a significantly higher stability than the plate osteosynthesis. CONCLUSION: Revision cup and ORIF withstood biomechanical loading forces exceeding full weight-bearing in this biomechanical study. The results of our study suggest that the cementless hip revision cup might be promising alternative to the current standard care of ORIF with or without primary THA. LEVEL OF EVIDENCE: III; case control experimental study.

Novel Tape Suture Osteosynthesis for Hyperextension Injuries of the Subaxial Cervical Spine: A Biomechanical Study.

BACKGROUND/AIM: Anterior tension band injuries are usually the result of high impact hyperextension trauma. Current surgical treatment includes anterior cervical discectomy and fusion bearing the risk of soft tissue irritation, degeneration of adjacent cervical segments, implant failure or iatrogenic spondylodesis. This study examined the biomechanical properties of tape suture constructs reenforcing ligamental stability for the treatment of Association of Osteosynthesis (AO) type B3 injuries compared to anterior fusion. MATERIALS AND METHODS: After creation of an AO type B3 injury in synthetic cervical segments (C5/6, Sawbone®), seven segments were treated with anterior fusion and seven with a tape suture construct, similar to the SpeedBridge™ (Arthrex®). Biomechanical testing was performed, simulating extension, flexion, lateral bending, and rotation. Dislocation (°) and corresponding force (N) were measured and compared. RESULTS: Anterior fusion displayed a mean range of extension, lateral bending, and rotation of 3.60° (SD 1.87°), 2.28° (SD 1.55°), and 2.81° (SD 0.78°), respectively. The tape suture showed a mean range of extension, lateral bending, and rotation of 4.24° (SD 0.81°) (p=0.146), 5.44° (SD 1.56°) (p=0.013), and 5.29° (SD 1.44°) (p<0.01), respectively. No specimen suffered from implant failure. CONCLUSION: The tape suture construct provides sufficient biomechanical stability for the treatment of AO type B3 injuries compared to anterior fusion. Regarding cervical extension, whose limitation is crucial for ligamental healing, the tape suture shows no significant inferiority. Yet, the tape suture approaches physiological mobility in the planes not affected by the injury. Consequently, the tape suture is a promising alternative preventing an iatrogenic spondylodesis.

A method for finding high accuracy surface zones on 3D printed bone models.

The use of three-dimensional (3D) printing for surgical applications is steadily increasing. Errors in the printed models can lead to complications, especially when the model is used for surgery planning or diagnostics. In patient care, the validation of printed models should therefore be performed routinely. However, there currently is no standard method to determine whether the printed model meets the necessary quality requirements. In this work, we present a method that not only finds surface deviations of a printed model, but also shows high accuracy zones of a potentially corrupted model, that are safe to be used for surgery planning. Our method was tested on printed patient bone models with acetabular fractures and was compared to two common methods in orthopedics, simple landmark registration as well as landmark plus subsequent iterative closest point registration. In order to find suitable parameters and to evaluate the performance of our method, 15 digital acetabular bone models were artificially deformed, imitating four typical 3D printing errors. A sensitivity of over 95% and a specificity of over 99% was observed in finding these surface deformations. Then, the method was applied to 32 printed models that had been re-digitized using a computed tomography scanner. It was found that only 25% of these printed models were free of significant deformations. However, focussing on two common implant locations, our method revealed that 72% of the models were within the acceptable error tolerance. In comparison, simple landmark registration resulted in a 9% acceptance rate and landmark registration followed by iterative closest point registration resulted in a 41% acceptance rate. This outcome shows that our method, named Similarity Subgroups Registration, allows clinicians to safely use partially corrupted 3D printed models for surgery planning. This improves efficiency and reduces time to treatment by avoiding reprints. The similarity subgroups registration is applicable in further clinical domains as well as non-medical applications that share the requirement of local high accuracy zones on the surface of a 3D model.

Tape suture for stabilization of incomplete posterior pelvic ring fractures-biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures.

BACKGROUND: Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury. METHODS: Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring. RESULTS: At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999). Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711). CONCLUSION: The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

Modified less invasive anterior subcutaneous fixator for unstable Tile-C-pelvic ring fractures: a biomechanical study.

BACKGROUND: Operative procedures for unstable pelvic ring fractures remain controversially discussed. Minimally invasive treatment options for pelvic ring fractures have several benefits for the patient. But they can also provide disadvantages. Anterior subcutaneous pelvic fixation (INFIX) has shown promising biomechanical results in pelvic ring fractures, but there is a high complication rate of nerve injuries. An additional screw to the INFIX seems to be more stable. The aim of this study is to compare biomechanical stability of a new modified unilateral INFIX fixing the unilateral injured pelvic ring with the standard INFIX. METHODS: 24 composite synthetic full pelvises were used in this study. 4 groups each with a number of six pelvic specimens were randomly assigned. A C1.3-type pelvic fracture was made with an osteotomy of the sacrum and an osteotomy of the anterior pelvic ring. Fracture fixation was performed within the four groups: (1) unilateral INFIX, (2) "extended" unilateral INFIX + additional pubic ramus pedicle screw, (3) bilateral INFIX, (4) "extended" bilateral INFIX + additional pubic ramus pedicle screw. All specimens were cyclic loaded with 200 N until maximum of 300 N. Distance/dislocation of the fracture fragments were detected with 3D-ultrasound measuring system. Stiffness was calculated. RESULTS: Extended unilateral INFIX showed the lowest mean dislocation. Lowest rotational stability was displayed by the standard bilateral INFIX. A significant difference (P = 0.04) was shown between the extended unilateral INFIX and the "standard" bilateral INFIX in terms of rotational stability. Extended unilateral INFIX showed significantly improved stability of anterior fracture dislocation (P = 0.01) and unilateral INFIX showed the highest rotational stiffness. Anterior fixation stiffness of the unilateral INFIX was significantly improved using an additional symphysis/pubic ramus screw (P = 0.002). CONCLUSION: Extended unilateral INFIX (+ additional pubic ramus pedicle screw) is a feasible minimally invasive treatment for anterior pelvic ring fractures. Higher stability and lower probability of bilateral nerve damage is provided by the extended unilateral INFIX compared to the standard bilateral INFIX.