Murine iPSC-Loaded Scaffold Grafts Improve Bone Regeneration in Critical-Size Bone Defects.

In certain situations, bones do not heal completely after fracturing. One of these situations is a critical-size bone defect where the bone cannot heal spontaneously. In such a case, complex fracture treatment over a long period of time is required, which carries a relevant risk of complications. The common methods used, such as autologous and allogeneic grafts, do not always lead to successful treatment results. Current approaches to increasing bone formation to bridge the gap include the application of stem cells on the fracture side. While most studies investigated the use of mesenchymal stromal cells, less evidence exists about induced pluripotent stem cells (iPSC). In this study, we investigated the potential of mouse iPSC-loaded scaffolds and decellularized scaffolds containing extracellular matrix from iPSCs for treating critical-size bone defects in a mouse model. In vitro differentiation followed by Alizarin Red staining and quantitative reverse transcription polymerase chain reaction confirmed the osteogenic differentiation potential of the iPSCs lines. Subsequently, an in vivo trial using a mouse model (n = 12) for critical-size bone defect was conducted, in which a PLGA/aCaP osteoconductive scaffold was transplanted into the bone defect for 9 weeks. Three groups (each n = 4) were defined as (1) osteoconductive scaffold only (control), (2) iPSC-derived extracellular matrix seeded on a scaffold and (3) iPSC seeded on a scaffold. Micro-CT and histological analysis show that iPSCs grafted onto an osteoconductive scaffold followed by induction of osteogenic differentiation resulted in significantly higher bone volume 9 weeks after implantation than an osteoconductive scaffold alone. Transplantation of iPSC-seeded PLGA/aCaP scaffolds may improve bone regeneration in critical-size bone defects in mice.

Parkland Trauma Index of Mortality in Orthopaedic Trauma Patients: An Initial Report.

OBJECTIVES: The extent and timing of surgery in severely injured patients remains an unsolved problem in orthopaedic trauma. Different laboratory values or scores have been used to try to predict mortality and estimate physiological reserve. The Parkland Trauma Index of Mortality (PTIM) has been validated as an electronic medical record-integrated algorithm to help with operative timing in trauma patients. The aim of this study was to report our initial experience with PTIM and how it relates to other scores. METHODS: A retrospective chart review of level 1 and level 2 trauma patients admitted to our institution between December 2020 and November 2022 was conducted. Patients scored with PTIM with orthopaedic injuries were included in this study. Exclusion criteria were patients younger than 18 years. RESULTS: Seven hundred seventy-four patients (246 female patients) with a median age of 40.5 (18-101) were included. Mortality was 3.1%. Patients in the PTIM high-risk category (≥0.5) had a 20% mortality rate. The median PTIM was 0.075 (0-0.89) and the median Injury Severity Score (ISS) was 9.0 (1-59). PTIM (P < 0.001) and ISS (P < 0.001) were significantly lower in surviving patients. PTIM was mentioned in 7.6% of cases, and in 1.7% of cases, providers indicated an action in response to the PTIM. PTIM and ISS were significantly higher in patients with documented PTIM. CONCLUSION: PTIM is better at predicting mortality compared with ISS. Our low rate of PTIM documentation in provider notes highlights the challenges of implementing a new algorithm. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Vitamin C as a Potential Prophylactic Measure Against Frozen Shoulder in an In Vivo Shoulder Contracture Animal Model.

BACKGROUND: Frozen shoulder is a common, painful, and movement-restricting condition. Although primary frozen shoulder is idiopathic, secondary frozen shoulder can occur after trauma or surgery. Prophylactic and therapeutic options are often unsatisfactory. Vitamin C (ascorbic acid) is a potent physiological antioxidant and likely inhibits the activation of nuclear factor κB, which plays a decisive role in inflammatory reactions. HYPOTHESIS: Because of its anti-inflammatory effects, vitamin C may be valuable in the prevention of secondary frozen shoulder. STUDY DESIGN: Controlled laboratory study. METHODS: An in vivo shoulder contracture model was conducted by fixation of the right proximal limb of Sprague-Dawley rats. A treatment group (n = 8) receiving vitamin C orally was compared with a control group (n = 9) without vitamin C. The primary outcome was capsular thickness at the shoulder joint measured on magnetic resonance imaging (MRI) examination. Further histological examination was performed but was not statistically analyzed because of variability of the cutting plane through the glenoid. RESULTS: Vitamin C treatment resulted in less thickening of the axillary fold of the operated shoulder at 2 of the 3 locations measured on MRI compared with untreated controls (insertion to the glenoid, P = .074; insertion to the humerus, P = .006; middle of the axillary recess, P = .008). The observed structural changes in histological examination corroborated the significant changes obtained from the MRI measurements. CONCLUSION: Prophylactic vitamin C seemed to reduce the thickening of the axillary recess in secondary frozen shoulder in this preclinical study. CLINICAL RELEVANCE: Vitamin C may be helpful as a noninvasive therapeutic measure to prevent secondary frozen shoulder (eg, within the context of surgery in the shoulder region or immobilization) or to treat primary frozen shoulder at an early stage. Further studies are required to evaluate the effect of this treatment in humans and the necessary dosage in humans.

SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model.

Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals.

Does the accuracy of prehospital pelvic binder placement affect cardiovascular physiological parameters during rescue? A clinical study in patients with pelvic ring injuries.

Introduction: Pelvic binders (PB) have become an established first-line treatment for on scene use in suspected pelvic ring injuries. A sustained incidence of incorrect placements was reported, usually above the trochanteric region. We examined if malplacement is associated with worse clinical parameters related to resuscitation. Methods: Retrospective chart review, level 1 center over a 3-year period. Inclusion criteria: adult patients (18-69y/o), high-energy injury, presence of a pelvic binder on admission - patients without binders served as controls. Exclusions: geriatric patients (>70y/o), ground level falls. Malplacement of the binder was assessed and graded (grade 1:<5 cm above trochanter, grade 2:5-10 cm, grade 3 > 10 cm) from the initial computed tomography scan (3D reconstruction). Results: Seventy-six patients were included. Males (72%), mean age 47years (range 18-91, SD 19.4). Mean Injury Severity Score was 22.3 points (range 1 -48, SD 10.4) and mean Glasgow Coma Score on arrival was 10.8 points (range 3-15, SD 5.3). Fifty-three percent presented with a pelvic ring injury (74% of them with a type B or C fracture). Mean PB distance from the trochanteric region was 56 mm (range 41-247 mm, SD 54.5). Fifty percent of PBs were moderately displaced, 21% showed severe misplacement (>100 mm). Physiological parameters were unchanged regardless of the accuracy of PB placement. Conclusion: Incorrect placement of pelvic binders persists despite widespread implementation of the device. In our series, displacement was always cranially and had no effect on preclinical fluids received or parameters of resuscitation on arrival. Level of Evidence: III.

Early fixation strategies for high energy pelvic ring injuries - the Zurich algorithm.

In isolated high energy pelvic ring injuries, early surgical and nonsurgical fixation belongs to the rescue tools required for rapid recovery. With the increasing use of pelvic binders on scene, these patients frequently arrive in a better condition at the level I trauma centre than without any measures of immobilisation. We describe our surgical tools to achieve rapid fixation within the first hours after arrival, taking into account if additional injuries or special stations are relevant.

KPC-50 Confers Resistance to Ceftazidime-Avibactam Associated with Reduced Carbapenemase Activity.

KPC-50 is a KPC-3 variant identified from a Klebsiella pneumoniae clinical isolate recovered in Switzerland in 2019. Compared to KPC-3, KPC-50 shows (i) a three-amino-acid insertion (Glu-Ala-Val) between amino acids 276 and 277, (ii) an increased affinity to ceftazidime, (iii) a decreased sensitivity to avibactam, explaining the ceftazidime-avibactam resistance, and (iv) an association with a sharp reduction of its carbapenemase activity.

Psychiatric outcome at least 20 years after trauma: A survey on the status of subjective general health and psychiatric symptoms with a focus on posttraumatic stress disorder.

BACKGROUND: Information on long-term psychiatric sequelae after severe trauma is sparse. We therefore performed a survey addressing several symptoms related to posttraumatic stress disorder (PTSD) in patients who sustained multiple injuries more than 20 years after trauma. METHODS: Patients injured between January 1, 1973, and December 31, 1990, were contacted at least 20 years later. We included multiply injured patients aged between 3 and 60 years from a single level 1 trauma center. A questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnostic criteria for PTSD, including individual symptoms related to intrusion, avoidance, and hyperarousal was sent to all patients. RESULTS: A total of 359 patients (56.35%) received a questionnaire. Of these, 337 patients (93.87%) returned the questionnaire and were included in the study (223 males [66.17%] and 114 females [33.82%]). Mean ± SD follow-up was 29.5 ± 8.5 years. Nearly half the study population (47.18%) experienced lasting psychiatric sequelae, such as intrusive recollection (n = 65, 19.28%), avoidance (n = 92, 27.29%), or hyperarousal (n = 95, 28.18%) at least monthly. Ten patients (2.96%) fulfilled all Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnostic criteria for PTSD. A total of 131 patients (38.87%) reported fair or poor general health status. There was no difference in injury severity in patients with or without PTSD (injury severity score, 8.33 vs. 20.36, respectively; p = 0.52) or PTSD-related symptoms including intrusion (19.88 vs. 20.32, p = 0.74), avoidance (19.99 vs. 20.3, p = 0.79), and hyperarousal (19.36 vs. 20.68, p = 0.26). CONCLUSION: At least 20 years after injury, no correlation was found between the development of psychiatric complications and the severity of injury. While the rate of full-blown PTSD was low, nearly half the study population regularly suffered from at least one psychiatric symptom attributable to the initial trauma. Awareness for the development of psychiatric complications and early initiation of psychiatric counseling are advisable. LEVEL OF EVIDENCE: Prognostic and epidemiologic, level II.

Quality of reduction correlates with clinical outcome in pelvic ring fractures.

INTRODUCTION: Posttraumatic pelvic deformity is associated with pain and loss of function. This study aimed to test the correlation of functional outcome in patients with pelvic fractures with the postoperative radiographic quality of reduction. METHODS: Consecutive patients with an isolated traumatic pelvic fracture that required closed or open reduction between 07/2015 and 07/2017 and had a completed follow-up of at least 6 months were included (N = 31, mean age 50 years, SD 21 years, range, 16 to 88 years). Majeed and Timed Up & Go were obtained from a prospective outcome database at 6 months and last follow-up (mean 10 months, SD 5 months). Quality of pelvic ring reduction was determined on postoperative radiographs as described by Matta, Sagi and Keshishyan/Lefaivre. RESULTS: Clinical outcome at 6 months as measured by the Majeed and the Timed Up & Go correlated moderately with Keshishyan/Lefaivre's pelvic asymmetry value (Pearson R: -0.520 and 0.585, p ≤ 0.003) and the pelvic deformity index (-0.527 and 0.503, p ≤ 0.004). There was a weak correlation between the Timed Up & Go and the radiographic grading system as described by Matta/Tournetta at 6 months (0.408, p = 0.023) and at last follow-up (0.380, p = 0.035). CONCLUSIONS: This study showed a moderate correlation of the clinical outcome at 6 months with postoperative quality of radiographic reduction when measured with the method described by Keshishyan and Lefaivre. Although having only descriptive value due to the small cohort, our findings underline the importance of anatomic reduction and restoration of pelvic symmetry in patients with pelvic trauma. Future studies with more patients and more investigators are required and reliability and validity of functional outcome scores needs to be further assessed to predict outcome in patient with fractures of the pelvic ring. LEVEL OF EVIDENCE: Level IV (case series).

Correlation of radiographic variables to guide safe implant positioning during acetabular surgery and hip replacement: a retrospective observational study.

BACKGROUND: Knowledge of periacetabular anatomy is crucial for prosthetic cup placement in total hip arthroplasty and for screw placement in anterior fixation with acetabular fractures. It is known that degree of hip dysplasia correlates with medial bone stock and that medial bone stock shows a weak correlation to Lequesne's acetabular index (AI). Aim of this study was to investigate a possible correlation between AI and the newly proposed medial safe zone. METHODS: AI and the medial save zone were measured on 419 hips using a computed-tomography scan of the pelvis. AI was assessed on a 2D reconstructed anterior-posterior view of the pelvis using VOXAR™. Correlation was measured using the Pearson correlation coefficient. RESULTS: Mean AI was 4.2 degrees (SD 4.9 degrees). Mean medial safe zone was 8.1 mm (SD 1.9 mm). There was a significant correlation between AI and medial save space with a Pearson correlation coefficient r = 0.33 (p = .001). CONCLUSION: There is a weak correlation between AI and medial safe zone. AI should not be used to predict medial safe zone. Due to the weakness in correlation AI is not suited for predicting medial safe zone. However, a low or negative AI can be a warning sign for less medial safe zone, prompting surgeons to take care when reaming in THA or placing periacetabular screws.

Subcutaneous internal anterior fixation of pelvis fractures-which configuration of the InFix is clinically optimal?-a retrospective study.

INTRODUCTION: Subcutaneous internal fixation (InFix) has become a valid alternative for anterior fixation of pelvic ring injuries. Complications associated with this technique are lateral femoral cutaneous nerve (LFCN) irritation and anterior thigh pain due to prominent implants. The aim of this study was to identify a configuration of the InFix that causes the least adverse side effects. METHODS: Nineteen patients (6 females, mean age 61 years) with 38 hemipelves were included. Rod-to-bone distance and symphysis-rod distance were measured on AP- and outlet- radiographs. These distances were analyzed in relation to the primary outcomes: early removal of the InFix, post-operative complications and damage of the LFCN. RESULTS: Regarding rod-to-bone distance, a distance of 20 to 25 mm causes less complications, LFCN damage and no early removals of the InFix. Symphysis-to-rod distance analysis showed the best results regarding LFCN damage and other complications when the rod had a distance of less than 40 mm to the symphysis. A distance more than 40 mm was associated with fewer early removal of the InFix. CONCLUSIONS: Planned optimized configuration of the InFix with a rod-to-bone distance between 20 and 25 mm may reduce postoperative complications. Regarding LFCN damage, the rod-to-symphysis distance should not be more than 40 mm.

Standards for external fixation application: national survey under the auspices of the German Trauma Society.

INTRODUCTION: External fixation is widely accepted as a provisional or sometimes definitive treatment for long-bone fractures. Indications include but are not limited to damage control surgery in poly-traumatized patients as well as provisional bridging to definite treatment with soft tissue at risk. As little is known about surgeon's habits in applying this treatment strategy, we performed a national survey. METHODS: We utilized the member database of the German Trauma Society (DGU). The questionnaire encompassed 15 questions that addresses topics including participants' position, experience, workplace, and questions regarding specifics of external fixation application in different anatomical regions. Furthermore, we compared differences between trauma centre levels and surgeon-related factors. RESULTS: The participants predominantly worked in level 1 trauma centres (42.7%) and were employed as attendings (54.7%). There was widespread consensus for planning and intra-operative radiographical control of external fixation. Surgeons appointed at a level I trauma centre preferred significantly more often supra-acetabular pin placement in external fixation of the pelvis rather than the utilization of iliac pins (75.8%, p = 0.0001). Moreover, they were more likely to favor a mini-open approach to insert humeral pins (42.4%, p = 0.003). Overall, blunt dissection and mini-open approaches seemed equally popular (38.2 and 34.1%). Department chairmen indicated more often than their colleagues to follow written pin-care protocols for minimization of infection (16.7%, p = 0.003). CONCLUSION: Despite the fact that external fixation usage is widespread and well established among trauma surgeons in Germany, there are substantial differences in the method of application.

Mid-term follow-up after surgical treatment of fragility fractures of the pelvis.

INTRODUCTION: Early operative treatment of fragility fractures of the pelvis (FFP) has been suggested to reduce pain and allow for earlier mobilization. The aim of this study was to determine mortality and functional outcome after operative treatment. PATIENTS AND METHODS: Patients aged ≥60 years (n = 60; mean age 79 years, 53 female) who had operative treatment of a FFP and a follow-up of at least 2 years were identified and mortality was assessed using a national social insurance database. Those who had survived were contacted by phone and a modified Majeed Score was obtained. RESULTS: At final follow up (62 months, range, 29-117), 32 patients (53.3%) had deceased. One-year-mortality rate was 28.3% and 2-year mortality was 36.7%. Mortality was not linked to fracture type (p > .05). Complications during hospitalization occurred in 26/60 patients (43.3%). Patients with a bilateral FFP had a longer hospitalization (18 vs. 11 days; p = .021). The mean modified Majeed score of surviving patients was 65 points (85.5% of achievable maximum). CONCLUSION: Mortality and in-hospital complications remain high among patients with FFP even when treated operatively. A longer hospitalization can be expected in patients with posterior bilateral fractures.

Single-level vertebral kyphoplasty is not associated with an increased risk of symptomatic secondary adjacent osteoporotic vertebral compression fractures: a matched case-control analysis.

This matched case-control study compared the rate of symptomatic adjacent-level vertebral compression fractures (VCF) within 1 year in patients operatively treated with kyphoplasty to a control group of non-operatively treated VCFs. The adjacent-level fracture rate did not show a significant difference between groups. PURPOSE: To compare the rate of new symptomatic adjacent-level fractures within 1 year after an isolated osteoporotic vertebral compression fracture (VCF) treated by either kyphoplasty or non-operative treatment. METHODS: Patients aged ≥ 50 years with an isolated, fresh, and symptomatic osteoporotic VCF who were treated by kyphoplasty were compared to patients of similar age, gender, vertebral segment, and bone mineral density who were treated non-operatively (n = 98). A matched case-control analysis was conducted by retrospective chart review, and the rate of new adjacent-level symptomatic vertebral fractures, defined as occurring within two segments of the index fracture, within the first year was determined. RESULTS: Ninety-eight patients (66 female, aged 73.5, SD 9.7 years) were analyzed in this matched case-control study. The adjacent fracture rate within 1 year was not different between the kyphoplasty group and the non-operative group (20.4 vs 18.4%; McNemar, p = 1.0). The time to a new adjacent fracture after the index fracture was significantly shorter in the kyphoplasty (7, SD 8 weeks) versus non-operative group (22, SD 13 weeks). CONCLUSIONS: Patients with osteoporotic VCFs treated with kyphoplasty did not show an increased rate of additional symptomatic adjacent-level VCFs when compared to a non-operative control group matched for age, gender, fracture level, and bone mineral density. LEVEL OF EVIDENCE: Level III.

Medial acetabular wall breach in total hip arthroplasty - is full-weight-bearing possible?

BACKGROUND: A breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: immediate postoperative full-weight-bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, and increases the risk for migration of the acetabular component? HYPOTHESIS: Immediate full-weight-bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup. PATIENTS AND METHODS: In this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow-up 23±17 months, range 6 to 79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up. RESULTS: Some extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow-up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow-up (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap [distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views]: -0.5±0.9mm [range, -2.9 to 0.8] vs. -0.3±1.7mm [range, -1.9 to 2.2], Δ overlap tangent [defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views]: -2.2±6.1mm [range, -21.4 to 0.0] vs. 0.4±6.9mm [range, -6.2 to 17.6]). Similarly, according to variation in the ilio-ischial overlap distance between postoperative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration ≥ 5mm in the control group versus 1/25 (4%) in the medial breach cohort (p=0.3). DISCUSSION: In this retrospective observation of patients with immediate postoperative full-weight-bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial weight-bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable. LEVEL OF EVIDENCE: IV, Retrospective cohort study.

Correlation of pelvic incidence with radiographical parameters for acetabular retroversion: a retrospective radiological study.

BACKGROUND: Pelvic incidence (PI) has been linked to several degenerative processes within the spinopelvic system. Acetabular retroversion is a recognised risk factor for osteoarthritis of the hip. We therefore hypothesised that these two factors might be part of a specific anatomical variant associated with degenerative changes. This study was performed to clarify this issue. METHODS: The pelvic incidence was measured on 589 computertomographical data sets acquired between 2008 and 2010. For 220 patients a 2D rendering in an antero-posterior view of the CT data set was performed to evaluate the parameters of acetabular retroversion. Those included the prominence of the ischial spine sign (PRISS), the cross-over sign (COS) and the posterior wall sign (PWS). Between 477 and 478 hips were evaluated depending on the parameter of retroversion. RESULTS: The mean pelvic incidence was significantly lower in hips positive for the PRISS and the PWS. However, there were no significant differences between hips positive or negative for the COS. DISCUSSION: As hypothesised, the lower PI values in PWS and PRISS positive hips suggest a link between PI and retroversion of the acetabulum. Whether this is of any clinical relevance remains, however, unknown. CONCLUSION: Acetabular retroversion is linked to PI. In hips where the prominence of the ischial spine sign and/or the posterior wall sign was present, the mean pelvic incidence value was lower.

Mechanical testing of a device for subcutaneous internal anterior pelvic ring fixation versus external pelvic ring fixation.

BACKGROUND: Although useful in the emergency treatment of pelvic ring injuries, external fixation is associated with pin tract infections, the patient's limited mobility and a restricted surgical accessibility to the lower abdomen. In this study, the mechanical stability of a subcutaneous internal anterior fixation (SIAF) system is investigated. METHODS: A standard external fixation and a SIAF system were tested on pairs of Polyoxymethylene testing cylinders using a universal testing machine. Each specimen was subjected to a total of 2000 consecutive cyclic loadings at 1 Hz with sinusoidal lateral compression/distraction (+/-50 N) and torque (+/- 0.5 Nm) loading alternating every 200 cycles. Translational and rotational stiffness were determined at 100, 300, 500, 700 and 900 cycles. RESULTS: There was no significant difference in translational stiffness between the SIAF and the standard external fixation when compared at 500 (p = .089), 700 (p = .081), and 900 (p = .266) cycles. Rotational stiffness observed for the SIAF was about 50 percent higher than the standard external fixation at 300 (p = .005), 500 (p = .020), and 900 (p = .005) cycles. No loosening or failure of the rod-pin/rod-screw interfaces was seen. CONCLUSIONS: In comparison with the standard external fixation system, the tested device for subcutaneous internal anterior fixation (SIAF) in vitro has similar translational and superior rotational stiffness.

Anterior subcutaneous internal fixation for treatment of unstable pelvic fractures.

BACKGROUND: Fractures of the pelvic ring including disruption of the posterior elements in high-energy trauma have both high morbidity and mortality rates. For some injury pattern part of the initial resuscitation includes either external fixation or plate fixation to close the pelvic ring and decrease blood loss. In certain situations--especially when associated with abdominal trauma and the need to perform laparotomies--both techniques may put the patient at risk of either pintract or deep plate infections. We describe an operative approach to percutaneously close and stabilize the pelvic ring using spinal implants as an internal fixator and report the results in a small series of patients treated with this technique during the resuscitation phase. FINDINGS: Four patients were treated by subcutaneous placement of an internal fixator. Screw fixation was carried out by minimally invasive placement of two supra-acetabular iliac screws. Afterwards, a subcutaneous transfixation rod was inserted and attached to the screws after reduction of the pelvic ring. All patients were allowed to fully weight-bear. No losses of reduction or deep infections occurred. Fracture healing was uneventful in all cases. CONCLUSION: Minimally invasive fixation is an alternative technique to stabilize the pelvic ring. The clinical results illustrate that this technique is able to achieve good results in terms of maintenance of reduction the pelvic ring. Also, abdominal surgeries no longer put the patient at risk of infected pins or plates.