Search Results (19)

Background: Unstable pelvic ring injuries often require surgical stabilization to restore pelvic ring integrity. The anterior subcutaneous internal fixator, or pelvic INFIX, has emerged as an alternative to external fixation and open anterior fixation. This study evaluated the functional, radiographic, and complication-related outcomes of INFIX fixation for unstable anterior pelvic ring injuries. Methods: We retrospectively reviewed 21 adult patients treated with anterior pelvic INFIX for unstable anterior pelvic ring fractures, with or without posterior fixation, at a Level 1 Trauma Center between 2017 and 2024. Fractures were classified according to the AO/OTA system. Functional outcomes were assessed using the Iowa Pelvic Score and Short Form-12 questionnaire. Radiographic outcomes were evaluated according to Tornetta and Matta criteria. Complications were recorded throughout follow-up. The INFIX device was routinely removed 6 months postoperatively. Results: The cohort included 15 males and six females, with a mean age of 42.5 ± 11.1 years. Mean Injury Severity Score was 25.3 ± 9.6, and mean follow-up after implant removal was 31 (IQR 28–34) months. The mean Iowa Pelvic Score was 80.2 ± 7.4, indicating an overall good functional outcome. Mean SF-12 physical and mental scores were 49.2 ± 3.5 and 48.3 ± 7.9, respectively. Radiographic outcomes were excellent in eight patients, good in 11, and fair in two. Complications included postoperative hemorrhage, implant loosening, heterotopic ossification, and three cases of lateral femoral cutaneous nerve (LFCN) injury. Conclusions: INFIX fixation appears to be a reliable minimally invasive option for unstable anterior pelvic ring injuries, providing satisfactory mid-term functional and radiographic outcomes with an acceptable complication profile. Full article

This research investigated the feasibility of 3D-printed external fixator (EF) rings made from carbon fiber reinforced polyamide 6 (PA6-CF) as an alternative to the conventional metallic counterpart. The study integrated tensile testing with digital image correlation (DIC) in as-printed and cold plasma-sterilized conditions, finite-element analysis (FEA) under wire loading, topology optimization for material and energy reduction, and evaluation of printability limits for large PA6-CF rings. The average Young’s modulus was 4.76 GPa and the maximum tensile strength was 60.5 MPa for as-printed samples, decreasing by 6.4% and 10.4% after sterilization, respectively. Using these properties as model inputs, FEA predicted safety factors larger than 1.42 for all configurations under 1000 N wire pretension, while topology optimization targeted up to 50% mass reduction without compromising ring stiffness. The study also revealed challenges in the printability of PA6-CF for large and thin components, including dimensional contraction, significant warping and moisture-induced defects, requiring an experienced 3D printer operator. Full article

Management of septic arthritis of the pubic symphysis (SAS) presents with substantial clinical challenges. Firstly, the SAS is an extremely rare entity. Surgical resection of the symphysis plus targeted antibiotic therapy is a widely adopted treatment course. Some patients suffering from SAS develop posterior pelvic insufficiency fractures because of the weakened anterior pelvic ring or as a result of radiation therapy received during treatment for a malignant disease in the lesser pelvis. The literature demonstrates a lack of standardized strategies for restoring pelvic ring integrity based on pelvic instability and posterior pelvic insufficiency fractures caused by SAS. Background and Objectives: This study aimed to determine whether early, primary stand-alone dorsal fusion can be a viable treatment option in SAS and whether there is a clinical benefit compared with temporary anterior fixation or secondary posterior stabilization after failed anterior fixation. Materials and Methods: We performed a descriptive, retrospective analysis covering an eight-year period (2018–2025) including 21 patients who underwent symphyseal resection for destructive SAS. We evaluated peri- and postsurgical data to describe the different surgical methods and their respective outcomes. Results: Ten patients (10/21, 48%) received posterior stabilization (sacroiliac-joint fusion or spinopelvic stabilization). Seven patients (7/21, 33%) were anteriorly fixated either temporarily with an external fixator or permanently with ventral plate osteosynthesis. Four patients (4/21, 19%) did not receive any pelvic stabilization following symphyseal resection as pelvic integrity was present. Three of them (3/21, 14%) showed spontaneous sacroiliac-joint fusion, while 6/7 (86%) of anteriorly fixed patients presented with debilitating sacral insufficiency fractures, had longer hospital stays and a higher count of readmissions and re-operations. Primary posterior stabilization led to shorter hospital stays, less readmissions, and good clinical outcome. Conclusions: Primary posterior stabilization can be a viable course of treatment of SAS and should be considered especially when spontaneous sacroiliac-joint fusion is not present. We suggest that early stabilization of the posterior pelvic ring could be a sensible course of treatment and may prevent debilitating insufficient fractures. While there are many different surgical options for posterior stabilization available (spinopelvic/lumbosacral stabilization, sacroiliac-joint fusion and others), our preliminary data suggest that primary sacroiliac-joint fusion is a quick, minimally invasive and effective way to establish posterior pelvic stability. Full article

Background: Flap-based and podoplastic limb salvage in the foot and ankle is difficult due to the presence of biomechanical forces that can impact flap healing and complication rates and, in turn, limb salvage rates. For this reason, external fixation is indicated to neutralize forces across the flap interface and allow for optimal flap take and healing. Although external fixation for flap immobilization is the current standard of care, not much is known about how duration and timing may impact complication and salvage rates. Methods: We retrospectively identified and analyzed complication and limb salvage rates in 18 patients who underwent flap-frame immobilization with a multiplanar external fixator during a 4.75-year period. Results: Patients ranged in age from 40 to 75 years (mean, 55.5 years). Sixteen patients (88.9%) had diabetes mellitus, and all had defects that were a mean of 110.9 cm² (range, 36–500 cm²) and required the use of a local or free flap. Thirteen defects (72.2%) were in the plantar region, with the remaining five (27.8%) in nonplantar regions. Eleven flaps (61.1%) were fasciocutaneous, and the remaining seven (38.9%) were vascularized muscle flaps. All of the flaps were immobilized with either a three- or four-ring circular external fixator. Overall, a 66.7% limb salvage rate (12 of 18) was observed with mean follow-up of 2.4 years, or 892.6 days (range, 222–1,555 days). Seven minor flap complications (38.9%) required a return to the operating room. Conclusions: External fixation is an essential tool in flap-based limb salvage. These findings hint that the “Goldilocks zone” of duration is approximately 28 to 35 days. Furthermore, we believe that risk factors such as open amputation, increased defect size, and presence of Charcot’s neuroarthropathy impact limb salvage rates regardless of duration and timing of flap-frame immobilization. Full article

Background: Circular ring external fixation has been found to be successful in the treatment of a wide range of foot and ankle pathologies, particularly in patients with multiple comorbidities and soft-tissue compromise, but the procedures are technically demanding, and complications are common. The primary goal of this study was to identify complications associated with circular ring external fixation, and the secondary aim was to identify any independent risk factors associated with them. Full article

This study evaluates the feasibility of 3D-printed polymer composite external fixator (EF) rings as a cost-effective alternative to stainless steel fixators, focusing on hybrid fixators for complex tibial fractures. Mechanical performance was assessed in three stages: (1) evaluating the initial EF–tibia configuration under axial loading and wire pre-tension conditions; (2) analyzing the stiffness evolution and weight-bearing capacity during early healing with progressive callus formation; and (3) optimizing ring designs through numerical analysis to improve structural performance under increased pre-tension. The results showed that, for the metallic EF, the axial displacement under one-leg stance reached 8.41 mm without pre-tension, reducing to 6.83 mm at 500 N pre-tension, though transverse displacement remained significant, suggesting the need for higher wire tension. Callus formation enhanced the load-bearing capacity, as expected. However, excessive displacements persisted under the one-leg stance, indicating that full weight-bearing should be delayed beyond two weeks for a fracture gap of 3 mm. A ring design assessment showed that full-ring configurations with two wires per ring improved performance. The 3D-printed full-ring design made of carbon-fiber-reinforced polylactic acid (PLA-CF) reduced stress by 85% at 500 N pre-tension compared to the initial configuration, remaining within allowable limits. While confirming feasibility, the study highlights the need for geometric refinements to accommodate higher preloads and improve transverse stiffness. Full article

Background: Charcot’s neuroarthropathy (CN) is a destructive inflammatory process that affects patients with peripheral neuropathy, most commonly those with uncontrolled diabetes mellitus. The disease progresses through an active hyperemic phase that eventually becomes inactive, and the affected bone consolidates. The period in which the disease progresses from active to inactive is when instability, deformity, dislocation, and ulceration may occur depending on what deforming forces are stressing the affected pathologic area. There is a paucity of literature to support early primary surgical intervention, either single or staged, for active CN. Methods: The purpose of this case series was to retrospectively review 30 reconstructions in 30 patients who underwent primary surgical intervention for active midfoot and ankle CN. All of the 30 patients underwent staged deformity correction with temporary circular ring external fixation followed by definitive internal fixation. Results: Twenty-seven of the staged reconstructions (90%) at final follow-up resulted in limb salvage with no minor amputations after reconstruction. Mean final follow-up was 24.4 months. Nine of the 30 patients (30%) did not remain ulcer-free; however, 50% of the patients had a preexiting ulceration before surgical intervention, and the cohort exhibited a 40% healing rate of ulcers. Conclusions: We achieved a 90% limb salvage rate in patients with active midfoot and ankle CN with a staged surgical intervention protocol. Surgical intervention in the active stage of CN may be beneficial for patients who have gross instability with ulceration, significant midfoot collapse, and frank dislocation. Full article

In preceding research endeavors, the frequency characteristics of a ring resonator on surface acoustic waves made of various materials were studied. Investigations encompassed fixation techniques within the housing, the impact of external variables on these components, and the most efficient configuration of the interdigital transducer within the ring resonator to curtail bandwidth. This current study is dedicated to investigating the correlation between sensitivity and the highest measurable acceleration concerning the dimensions of these sensitive elements. Furthermore, it involves assessing the attributes of produced experimental samples to verify the simulation results. The results obtained represent the possibility of creating a micromechanical accelerometer that can be used in the automotive industry as a g-sensor shock, as well as in industries where the numerical value of high overloads is required. Full article

Background: Congenital pseudoarthrosis of the tibia (CPT) remains a challenge for physicians. Several treatment options have been proposed, but the standard of care remains inconclusive. In this study, we present three patients for whom the failure of prior treatments was managed with a contralateral vascularized fibular bone graft (VFG) and an anatomic distal tibial locking plate. Methods: Between 2017 and 2021, three patients were referred for failed treatment of CPT. All patients had undergone multiple prior surgeries, including tumor excision and fixation with ring external fixators, plates, and screws. We performed radical tumor resection and reconstruction of bone defects with a VFG. The construct was fixed with an anatomic locking plate, and the patients were followed up for a mean of 45.7 months. Results: All three patients were able to obtain graft union at 19.3 weeks. At the final follow-up, all grafts achieved bony hypertrophy without evidence of bone resorption or local tumor recurrence. There was a mean leg length difference of 8.5 cm preoperatively, compared with 6.3 cm postoperatively. The average lower leg angulation was 7.4 degrees and the average ankle range of motion was 58.3 degrees. The mean VAS score was 0 and the mean AOFAS score was 88.3. No significant complications were noted. Conclusions: Implantation of a VFG and an anatomic distal tibia locking plate can be considered an option for treatment-refractory CPT. Patients can expect to achieve bone consolidation, ambulate as tolerated, and have a low complication rate. Full article

Background and Objectives: The stability of the pelvic ring mainly depends on the integrity of its posterior part. Percutaneous sacroiliac (SI) screws are widely implanted as standard of care treatment. The main risk factors for their fixation failure are related to vertical shear or transforaminal sacral fractures. The aim of this study was to compare the biomechanical performance of fixations using one (Group 1) or two (Group 2) standard SI screws versus one SI screw with bone cement augmentation (Group 3). Materials and Methods: Unstable fractures of the pelvic ring (AO/OTA 61-C1.3, FFP IIc) were simulated in 21 artificial pelvises by means of vertical osteotomies in the ipsilateral anterior and posterior pelvic ring. A supra-acetabular external fixator was applied to address the anterior fracture. All specimens were tested under progressively increasing cyclic loading until failure, with monitoring by means of motion tracking. Fracture site displacement and cycles to failure were evaluated. Results: Fracture displacement after 500 cycles was lowest in Group 3 (0.76 cm [0.30] (median [interquartile range, IQR])) followed by Group 1 (1.42 cm, [0.21]) and Group 2 (1.42 cm [1.66]), with significant differences between Groups 1 and 3, p = 0.04. Fracture displacement after 1000 cycles was significantly lower in Group 3 (1.15 cm [0.37]) compared to both Group 1 (2.19 cm [2.39]) and Group 2 (2.23 cm [3.65]), p ≤ 0.04. Cycles to failure (Group 1: 3930 ± 890 (mean ± standard deviation), Group 2: 3676 ± 348, Group 3: 3764 ± 645) did not differ significantly between the groups, p = 0.79. Conclusions: In our biomechanical setup cement augmentation of one SI screw resulted in significantly less displacement compared to the use of one or two SI screws. However, the number of cycles to failure was not significantly different between the groups. Cement augmentation of one SI screw seems to be a useful treatment option for posterior pelvic ring fixation, especially in osteoporotic bone. Full article

The rat model is a common model for intervertebral disc (IVD) and spinal research. However, complications remain challenging. Standard Operating Procedures (SOPs) are validated methods to minimize complications and improve safety and quality of studies. However, a SOP for rat spinal fusion surgery has been missing until now. Therefore, the aim of the study was to develop a SOP for spinal tail disc surgery in elderly Wistar rats (419.04 ± 54.84 g). An initial preoperative, intraoperative, and postoperative surgical setup, including specific anaesthesia and pain management protocols, was developed. Anaesthesia was induced by subcutaneous injection of a pre-mixture of fentanyl, midazolam, and medetomidin with the addition of 0.5% isoflurane in oxygen and caudal epidural analgesia. The surgery itself consisted of the fixation of a customized external ring fixator with ⌀ 0.8 mm Kirschner wires at the proximal rat tail and a discectomy and replacement with bone morphogenetic protein coated beta-tricalcium-phosphate carrier. The postoperative setup included heating, analgesia with buprenorphine, and meloxicam, as well as special supplementary food. Anaesthesia, surgery, and pain management were sufficient. In the presented optimized SOP, no animals developed any complications. A SOP for spinal surgery in elderly rats in an in vivo spinal fusion model was developed successfully. This novel protocol can improve transparency, reproducibility, and external validity in experimental rat spinal surgery experiments. Full article

Ankle joint distraction (AJD) has been described to be a valuable joint-sparing alternative to arthrodesis or arthroplasty; however, clinical endpoints associated to this surgical intervention are lacking. The current case report describes clinical and biomechanical outcome measures of ankle joint distraction in a 14-year-old patient with severe haemophilia A. Because of persistent and incapacitating pain and the poor response to conservative and invasive treatment options, ankle joint distraction was performed in this 14-year-old patient using an external fixator encompassing two Ilizarov full rings in the tibia and a foot ring fixed to the foot by four K-wires. State-of-the-art medical imaging and non-invasive skin marker-based 3D multi-segment foot modelling were performed in a pre- and post-operative stage. From a structural viewpoint, this AJD was a success since it improved and stabilised the osteo-cartilaginous lesions of the ankle. Biomechanical outcome measures associated with the 18-month follow-up were found to be suboptimal, showing an early plantarflexion pattern at the ankle joint during midstance and a tendency towards increased power absorption at the midfoot with peak power absorption being almost two times higher when compared to boys of the same age. From a functional viewpoint, we observed a clear reduction in the patients’ physical activities until one year after AJD. Despite these functional and structural improvements, recurrent painful phenomena, including the development of a complex regional pain syndrome (CRPS) and a stress fracture of the third metatarsal bone, were observed which are probably related with the development of recurrent subchondral oedema. Full article

Computed tomography (CT) is an essential tool in orthopedic surgery but is known to be a method with that entails radiation exposure. CT increases the risk of developing fatal cancer, which should not be underestimated. However, patients with bone defects and/or deformities must frequently undergo numerous investigations during their treatment. CT is used for surgical planning, evaluating callus maturation, alignment measurement, length measurement, torsion measurement, and angiography. This study explores the indications in CT scans for limb lengthening and deformity correction and estimates the effective radiation dose. These results should help avoid unnecessary radiation exposure by narrowing the examination field and by providing explicit scanning indications. For this study, 19 posttraumatic patients were included after the bone reconstruction of 21 lower limbs. All patients underwent CT examinations during or after treatment with an external ring fixator. The mean effective dose was 3.27 mSv, with a mean cancer risk of 1:117,014. The effective dose depended on the location and indication of measurement, with a mean dose of 0.04 mSv at the ankle up to 6.8 mSv (or higher) for vascular depictions. CT evaluation, with or without 3D reconstruction, is a crucial tool in complex bone reconstruction and deformity treatments. Therefore, strict indications are necessary to reduce radiation exposure—especially in young patients—without compromising the management of their patients. Full article

Background: Incidence of pelvic ring fractures has increased over the past four decades, especially after low-impact trauma—classified as fragility fractures of the pelvis (FFP). To date, there is a lack of biomechanical evidence for the superiority of one existing fixation technique over another. An FFP type IIc was simulated in 50 artificial pelvises, assigned to 5 study groups: Sacroiliac (SI) screw, SI screw plus supra-acetabular external fixator, SI screw plus plate, SI screw plus retrograde transpubic screw, or S1/S2 ala–ilium screws. The specimens were tested under progressively increasing cyclic loading. Axial stiffness and cycles to failure were analysed. Displacement at the fracture sites was evaluated, having been continuously captured via motion tracking. Results: Fixation with SI screw plus plate and SI screw plus retrograde transpubic screw led to higher stability than the other tested techniques. The S1/S2 ala–ilium screws were more stable than the SI screw or the SI screw plus external fixator. Conclusions: In cases with displaced fractures, open reduction and plate fixation provides the highest stability, whereas in cases where minimally invasive techniques are applicable, a retrograde transpubic screw or S1/S2 ala–ilium screws can be considered as successful alternative treatment options. Full article

There is currently no accurate data on fracture displacement during the rehabilitation of pelvic ring injuries. This study investigated the use of radiostereometric analysis (RSA) in assessing the stability of C1 pelvic ring injuries stabilised with a posterior plate and an anterior external fixator. Six patients, instructed to weight-bear as tolerated after surgery, were reviewed at 2, 4, 6, 12, 26, 52 and 104 weeks. The external fixators were removed at 6 weeks. Outcomes, including the Iowa Pelvic Score (IPS), and complications were recorded. Fracture stability was assessed using measurements on plain radiographs and RSA. All patients progressed to full weight-bearing without support within 6 weeks. At 104 weeks, the IPS was excellent in four patients, good in one patient and fair in one patient. Plain radiographs showed that all fractures were well reduced, and no loss of reduction occurred over time. By contrast, RSA measurements identified displacement in all cases. The maximum three-dimensional (3D) displacement at any time point in each patient ranged from 2 to 10 mm. Two patients with the largest displacement over time had the lowest IPS. RSA also demonstrated displacements above the currently defined normal threshold through the ‘un-injured’ sacroiliac joint in the same two patients, suggesting a subtle C2 injury, missed at initial assessment. This study demonstrates the limitations of plain radiographs in assessing pelvic fracture stability and displacement during healing, and the potential of RSA to monitor more accurately the effects of stabilisation and weight-bearing on fracture stability. Full article