Preliminary results of stabilization of far distal tibia fractures with the distal tibial nail: A prospective, multicenter case series study.

INTRODUCTION: The distal tibial nail (DTN) is a novel retrograde intramedullary nail used for distal tibial fracture stabilization. We investigated the clinical results of DTN use for distal tibial fractures and compared them with those reported in the literature on locking plates and antegrade intramedullary nails. MATERIALS AND METHODS: This multicenter, prospective, observational cohort study examined distal tibial fractures with AO/OTA classification 43 types: A1, A2, A3 or C1. The primary outcomes included bone union rate, soft tissue problems, and surgical complications. Secondary outcomes were EuroQol-5 Dimension-5 Level (EQ-5D-5L), Self-Administered Foot Evaluation Questionnaire (SAFE-Q), and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot clinical scores 1 year postoperatively. Incidence of varus or valgus/anterior-posterior flexion deformity with a difference of ≥5° and postoperative reduction loss rate were evaluated. RESULTS: Five men and five women were enrolled (mean age, 69 years [range, 30-77 years]), including one open-fracture-type Gustilo type IIIB case. Bone union was observed in all patients at 6 months postoperatively. Delayed union, leg edema, and guide pin breakage were observed in three, one, and one cases, respectively. No soft tissue or surgical complications were observed. During the final follow-up, the EQ-5D-5L, SAFE-Q, and AOFAS hindfoot scores were 0.876 (0.665-1.0), 83-92, and AOFAS 92.6 (76-100), respectively. Varus and retroflexion deformities were observed in one case each. DISCUSSION: DTN has been reported to have biomechanically equivalent or stronger fixation strength than locking plates or antegrade intramedullary nails. In addition, while DTN was thought to be less invasive for soft tissue and can avoid injury to the knee, it was thought that care should be taken to avoid medial malleolus fractures and posterior tibialis tendon injuries. Comparisons with literature treatment results for locking plates and antegrade intramedullary nails showed comparable to advantageous results. CONCLUSIONS: DTN treatment results for distal tibial fractures were as good as those for locking plates and antegrade intramedullary nails. DTN is useful for stabilization and does not compromise the surrounding soft tissues.

Fragility fractures of the pelvis: First 48 cases of surgical treatment at a level 1 trauma center in France.

INTRODUCTION: Longer life expectancy is accompanied by a higher incidence of fragility fractures of the pelvis (FFP), which has repercussions on mortality and nursing home admissions. Given the paucity of data at French healthcare facilities, we carried out a retrospective study to (1) evaluate how surgical treatment of FFP with posterior displacement (type III and IV according to Rommens and Hofmann) affects a patient's pain, functional status and ability to stay at home and (2) evaluate the postoperative complications and mortality rate. HYPOTHESIS: Surgery for posteriorly displaced FFP will relieve pain and preserve the patient's independence. METHODS: All the patients over 65 years of age who were operated on for a posterior FFP between January 2015 and August 2020 were included in this prospective, single-center study. The demographics, fracture type, details of the surgical treatment, complications and mortality were analyzed. Pain (visual analog scale, VAS), functional status (Activity of Daily Living [ADL] and Instrumental Activity of Daily Living [IADL]), mobility (Parker score) and rates of nursing home admissions were compared before the fracture, after surgery and at a mean follow-up of 28 months (minimum follow-up of 1 year). RESULTS: Forty-eight patients with a mean age of 75 years were included. Twenty-four of these patients (50%) had at least two comorbidities. The FFPs were either type IV (31/48; 65%) or type III (17/48; 35%). The mean VAS for pain was significantly lower on the first day postoperative (3.5 versus 4.8; p=0.02). This significant reduction continued upon discharge from the hospital (1.95; p=0.003) and persisted at the mean follow-up of 28 months (2.2; p=0.64). The complication rate was 15% (7/48) and the mortality rate at the final review was 15% (7/48). Among the surviving patients, 81% (29/36) returned to living at home. The ADL (5.1 versus 5.8; p=0.09), IADL (5.9 versus 6.9; p=0.15) and Parker score (6.8 versus 8.2; p=0.08) at the final review were not significantly different from the values before the fracture. CONCLUSION: This is the first French study of patients operated on for an FPP. Fixation of posteriorly displaced fractures allows surviving patients to retain their mobility. Pain relief is achieved quickly and maintained during the follow-up period. Thus, our initial hypothesis is affirmed. The complication rate is not insignificant; given the complexity of this surgery, percutaneous treatment is preferable. LEVEL OF EVIDENCE: IV; retrospective study.

Do we need to fix the anterior fracture component in insufficiency fractures of the pelvis? A biomechanical comparison on an FFP type IIIc fracture in an osteoporotic pelvic bone model.

There is a growing understanding of the specific characteristics of insufficiency fractures of the pelvis and of general requirements for the treatment of affected patients with focus on early mobilization and effective pain reduction as the main goals of therapy. While there is consensus on the significance of achieving stability of the dorsal pelvic ring structures there is still an open discussion about the potential benefits of additional stabilization of an anterior fracture component. Within a biomechanical test setup, two established methods of dorsal fracture fixation were tested under axial loading (25-1200 N; 1000 test cycles) on an explicit osteoporotic bone model (n = 32) with a standardized FFP type IIIc fracture with and without additional fixation of the anterior fracture component. Dorsal fixation was performed with and long and a short 7.3 mm cannulated screw in S1 in one group (n = 16), and a trans sacral bar with an additional short 7.3 mm cannulated screw in S1 in the other group (n = 16). Half of the samples received a 7.3 mm cannulated retrograde transpubic screw for anterior fixation. The fixation with the trans sacral bar and the additional anterior screw fixation showed the highest rate of stability (p = 0.0014), followed by the double SI-screw fixation with stabilization of the anterior fracture (p = 0.0002). During testing, we observed the occurrence of new sacral fractures contralateral to the initial fracture in 22/32 samples. The results let us assume that stabilization of an additional anterior fracture component relevantly improves the stability of the entire ring construct and might prevent failure of the dorsal stabilization or further fracture progression.

Design and fabrication of intracellular therapeutic cargo delivery systems based on nanomaterials: current status and future perspectives.

Intracellular cargo delivery, the introduction of small molecules, proteins, and nucleic acids into a specific targeted site in a biological system, is an important strategy for deciphering cell function, directing cell fate, and reprogramming cell behavior. With the advancement of nanotechnology, many researchers use nanoparticles (NPs) to break through biological barriers to achieving efficient targeted delivery in biological systems, bringing a new way to realize efficient targeted drug delivery in biological systems. With a similar size to many biomolecules, NPs possess excellent physical and chemical properties and a certain targeting ability after functional modification on the surface of NPs. Currently, intracellular cargo delivery based on NPs has emerged as an important strategy for genome editing regimens and cell therapy. Although researchers can successfully deliver NPs into biological systems, many of them are delivered very inefficiently and are not specifically targeted. Hence, the development of efficient, target-capable, and safe nanoscale drug delivery systems to deliver therapeutic substances to cells or organs is a major challenge today. In this review, on the basis of describing the research overview and classification of NPs, we focused on the current research status of intracellular cargo delivery based on NPs in biological systems, and discuss the current problems and challenges in the delivery process of NPs in biological systems.

The effect of losartan on the development of post-traumatic joint stiffness in a rat model.

Post-traumatic joint stiffness (PTJS) is accompanied by a multidimensional disturbance of joint architecture. Pharmacological approaches represent promising alternatives as the traumatic nature of current therapeutic standards may lead to PTJS' progression. Losartan is an auspicious candidate, as it has demonstrated an antifibrotic effect in other organs. Forty-eight Sprague Dawley rats were randomized into equally sized losartan or control groups. After a standardized knee trauma, the joint was immobilized for either 2 weeks (n = 16), 4 weeks (n = 16) or 4 weeks with re-mobilization for an additional 4 weeks (n = 16). Pharmacotherapy with losartan or placebo (30 mg/kg/day) was initiated on the day of trauma and continued for the entire course. Joint contracture was measured alongside histological and molecular biological assessments. There were no significant biomechanical changes in joint contracture over time, comparing short-term (2 weeks) with long-term losartan therapy (4 weeks). However, comparing the formation of PTJS with that of the control, there was a trend toward improvement of joint mobility of 10.5° (p 0.09) under the influence of losartan. During the re-mobilization phase, no significant effect of losartan on range of motion (ROM) was demonstrated. At a cellular level, losartan significantly reduced myofibroblast counts by up to 72 % (4 weeks, p ≤ 0.001) without effecting the capsular configuration. Differences in expression levels of profibrotic factors (TGF-ß, CTGF, Il-6) were most pronounced at week 4. The antifibrotic properties of losartan are not prominent enough to completely prevent the development of PTJS after severe joint injury.

Integrated osteoimmunomodulatory strategies based on designing scaffold surface properties in bone regeneration.

Those who have used traditional biomaterials as bone substitutes have always regarded the immune response as an obstacle leading to implant failure. However, cumulative evidence revealed that blindly minimizing host immune reactions cannot induce successful bone regeneration. With the emergence of the new concept of osteoimmunology, the intimate mutual effects between the skeletal system and the immune system have been gradually recognized, promoting the innovation of biomaterials with osteoimmunomodulatory properties. By tuning the surface properties, biomaterials can precisely manipulate the osteoimmune environment favoring bone regeneration. In this review, we first reviewed the mutual effects between the skeletal system and the immune system to show the importance of immunomodulation on bone regeneration. Subsequently, we summarize the recent developments in surface modification strategies in terms of the surface physicochemical properties and surface coatings and explain how these modification strategies work.

Bone Sialoprotein Immobilized in Collagen Type I Enhances Angiogenesis In Vitro and In Ovo.

Bone fracture healing is a multistep process, including early immunological reactions, osteogenesis, and as a key factor, angiogenesis. Molecules inducing osteogenesis as well as angiogenesis are rare, but hold promise to be employed in bone tissue engineering. It has been demonstrated that the bone sialoprotein (BSP) can induce bone formation when immobilized in collagen type I, but its effect on angiogenesis still has to be characterized in detail. Therefore, the aim of this study was to analyse the effects of BSP immobilized in a collagen type I gel on angiogenesis. First, in vitro analyses with endothelial cells (HUVECs) were performed detecting enhancing effects of BSP on proliferation and gene expression of endothelial markers. A spheroid model was employed confirming these results. Finally, the inducing impact of BSP-collagen on vascular density was proved in a yolk sac membrane assay. Our results demonstrate that BSP is capable of inducing angiogenesis and confirm that collagen type I is the optimal carrier for this protein. Taking into account former results, and literature showing that BSP also induces osteogenesis, one can hypothesize that BSP couples angiogenesis and osteogenesis, making it a promising molecule to be used in bone tissue regeneration.

The FFP-classification: From eminence to evidence.

Fragility fractures of the pelvis (FFP) are a clinical entity with a rapidly growing incidence among elderly women. The characteristics of these fractures are different from those appearing after high-energy trauma. In 2013, the comprehensive FFP-classification provided a new framework for analysis of these fractures. It is based on the estimation of loss of stability in the pelvic ring. It is connected with recommendations for surgical treatment, justified by the fact that higher instabilities will need surgical stabilization. Since it's appearance, we can observe an increasing clinical-scientific interest in FFP. Multiple publications use the FFP-classification studying the characteristics of fractures, choice of treatment and outcome. Other studies focus on minimal-invasive techniques for stabilization. The actual knowledge describes higher mortality rates as the reference population, lower mortality rates after operative treatment but for the price of surgery-related complications. Mobility, independency and quality of life are worse than before the fracture, independent of the FFP-classification and the type of treatment. The classification triggered a rapid increase of expertise. This publication gives a detailed overview on the evolution from eminence to evidence.

Internal fixation of radiation-induced fragility fractures of the pelvis: a case series.

BACKGROUND: The optimal treatment for radiation-induced fragility fractures of the pelvis (RI-FFP) is not well evaluated due to the rarity of the condition. PURPOSE: The aim of this retrospective study was to assess the prevalence of RI-FFP, the radiological and clinical outcomes as well as the complications of patients treated with internal fixation. METHODS: A retrospective review of our database was performed to identify all surgically treated patients with RI-FFP. Surgical stabilization was recommended for patients with FFP type III and FFP type IV. Surgical stabilization was also recommended after 5-7 days for patients with FFP type II in case of unsuccessful conservative treatment. Demographic data, fracture patterns according to the FFP classification of Rommens and Hofmann, type of treatment and surgery-related complications including nonunion, hardware failure, fracture progression (secondary fracture) or infection were documented. RESULTS: Among 500 patients with FFP, the prevalence of patients with RI-FFP was 1% (5/500): 5 patients with a median age of 79 years (76-79). The median time interval from radiation to fracture was 18 months (18-24). All of them underwent internal fixation. Two patients experienced surgery-related complications, one due to hardware failure and one due to fracture progression. At median follow-up of 27 months, all fractures had healed. Patients reached a good level of mobility with a median Parker Mobility Score of 7 and suffered moderate pain with a median value of 2.5 on the numeric rating scale. CONCLUSION: RI-FFP remains a rare injury (1%). In our experience, patients, who underwent surgical treatment, obtained a high level of mobility and a moderate pain score after 2 years of follow-up. Internal fixation can be recommended in RI-FFP. Because bone healing may be impaired due to previous irradiation, highly stable constructs are required to avoid fracture progression or revision surgery. LEVEL OF EVIDENCE: III, retrospective study.

Bone Sialoprotein Immobilized in Collagen Type I Enhances Bone Regeneration In vitro and In vivo.

The use of bioactive molecules is a promising approach to enhance the bone healing properties of biomaterials. The aim of this study was to define the role of bone sialoprotein (BSP) immobilized in collagen type I in various settings. In vitro studies with human primary osteoblasts in mono- or in co-culture with endothelial cells demonstrated a slightly increased gene expression of osteogenic markers as well as an increased proliferation rate in osteoblasts after application of BSP immobilized in collagen type I. Two critical size bone defect models were used to analyze bone regeneration. BSP incorporated in collagen type I increased bone regeneration only marginally at one concentration in a calvarial defect model. To induce the mechanical stability, three-dimensional printing was used to produce a stable porous cylinder of polylactide. The cylinder was filled with collagen type I and immobilized BSP and implanted into a femoral defect of critical size in rats. This hybrid material was able to significantly induce bone regeneration. Our study clearly shows the osteogenic effect of BSP when combined with collagen type I as carrier and thereby offers various approaches and options for its use as bioactive molecule in bone substitute materials.

Erratum to 'Impingement of the Sciatic Nerve due to a Protruding Acetabular Cage Rim' [Arthroplasty Today 6 (2020) 825-829].

[This corrects the article DOI: 10.1016/j.artd.2020.08.005.].

Is there a correlation between pelvic incidence and orientation of the acetabulum? An analysis based on a three-dimensional statistical model of the pelvic ring.

The pelvic ring is a complex anatomical structure building up the connection between the trunk and the legs. Whilst there is a broad discussion in the literature about the dynamic interaction between spine, pelvis and the hip joints, there is still little information about the relation and interaction of the constant pelvic parameters. Based on a three-dimensional (3D) statistical model consisting of 150 uninjured and bony healthy pelves (100 Europeans, 50 Japanese; 81 males, 69 females; average age 74.3 years ± 17.5 years) an evaluation of pelvic incidence (PI) and acetabular orientation in anteversion and inclination was performed and potential correlations of these intraindividual constant parameters were investigated. Pelvic incidence is defined as the angle between the perpendicular to the sacral plate at its midpoint and the line connecting this point to the middle axis of the femoral heads. Acetabular anteversion is defined as the angle between the perpendicular to the best-fit plane on the acetabular rim and the coronal plane measured in strict lateral view. Acetabular inclination is defined as the angle between the perpendicular to the best-fit plane on the acetabular rim and the sagittal plane in strict frontal view. Data were further analysed with regard to different subgroup's age, sex and ethnicity. A positive correlation between PI and acetabular anteversion could be demonstrated. Further, PI and also the acetabular parameters anteversion and inclination were found to be significantly higher in the European individuals than in the Asian. The results of the present study demonstrate a relation between the anatomical configuration of the constant pelvic parameters building up the connection points to the next proximal respectively caudal skeleton section. The findings might lead to more comprehensive treatment strategies in case of trauma or degenerative pathologies of the pelvis in the future.

Pain Intensity and Degree of Disability after Fragility Fractures of the Pelvis.

Background and objectives: Fragility fractures of the pelvis (FFP) are of increasing interest lately, being associated with a loss of mobility and affecting the quality of life. The aim of our study was to investigate the effect of FFP on disability and pain in patients, after one year since injury. Materials and Methods: In the study, we included 76 patients diagnosed with FFP, who were admitted to our trauma department between January 2016 and January 2019, and were above 65 years of age. The Von Korff pain intensity and disability scores were calculated in the hospital at 6 months and after 1 year. Results: Fifty-four patients were female (71%), with an average age of 75.9 ± 7.19 years. Twenty-two patients were male (29%) and had a mean age of 77.22 ± 7.33 years. We did not record significant differences regarding age between the men and women (p > 0.05). Significant improvements appeared between the baseline and the 6 month follow-up; the average pain intensity score at 6 months was 44.94 (SD 21.20) (p < 0.001), and the disability score was 54.30 (SD 21.62). The following average pain intensity and disability scores after 12 months were similar to the values at6 months: 44.48 (SD 21.74) for pain intensity and 52.36 (SD 24.53) for disability. The Von Korff pain score at 6 months and after 1 year depends on gender and on the initial Von Korff pain score (p = 0.02). The Von Korff disability score at 6 months depends on gender, the baseline pain score and the baseline disability score (p = 0.001). Conclusions: our patients reported long-lasting pain that had a severe effect on their daily routines, and they could not return to their normal status prior to injury.

Pleiotropic Long-Term Effects of Atorvastatin on Posttraumatic Joint Contracture in a Rat Model.

The antifibrotic effect of atorvastatin has already been demonstrated in several organ systems. In the present study, a rat model was used to investigate the effect of atorvastatin on posttraumatic joint contracture. Forty-eight Sprague Dawley rats were equally randomized into an atorvastatin group and a control group. After initial joint trauma, knee joints were immobilized for intervals of 2 weeks (n = 16) or 4 weeks (n = 16) or immobilized for 4 weeks with subsequent remobilization for another 4 weeks (n = 16). Starting from the day of surgery, animals received either atorvastatin or placebo daily. After euthanasia at week 2, 4 or 8, joint contracture was determined, histological examinations were performed, and gene expression was assessed. The results suggest that the joint contracture was primarily arthrogenic. Atorvastatin failed to significantly affect contracture formation and showed a reduction in myofibroblast numbers to 98 ± 58 (control: 319 ± 113, p < 0.01) and a reduction in joint capsule collagen to 60 ± 8% (control: 73 ± 9%, p < 0.05) at week 2. Gene expression of α-smooth muscle actin (α-SMA), collagen type I, transforming growth factor ß1 (TGF-ß1) and interleukin-6 (IL-6) was not significantly affected by atorvastatin. Atorvastatin decreases myofibroblast number and collagen deposition but does not result in an improvement in joint mobility.

[Minimally invasive stabilization of fragility fractures of the pelvis with transsacral bar and retrograde transpubic screw]. / Minimal-invasive Stabilisierung von Fragilitätsfrakturen des Beckens mittels transsakralem Stab und retrograder transpubischer Schraube.

OBJECTIVE: Stabilization of fragility fractures of the pelvis (FFP) using a minimally invasive technique. Insertion of a transsacral rod into the transsacral corridor of S1. Insertion of a retrograde transpubic screw through the superior branch of the pubic bone. INDICATIONS: Uni- or bilateral displaced fragility fractures of the sacrum or sacroiliac joint. Nondisplaced fractures of the sacrum or sacroiliac joint in case of nonsuccessful conservative treatment. Uni- or bilateral fractures of the superior branch of the pubic bone, which are present in combination with a posterior pelvic instability. CONTRAINDICATIONS: Fragility fractures of the pelvis, which can be successfully treated conservatively. Absence of transsacral corridor in sacral body S1. Major displacement, nonreducible fractures of the superior branch of the pubic bone. Soft tissue infection at insertion site of implants. SURGICAL TECHNIQUE: The transsacral bar is inserted under fluoroscopic control from ilium to ilium through the transsacral corridor of the sacral body S1. The retrograde transpubic screw is inserted from the pubic tubercle through the superior branch of the pubic bone past the acetabulum into the body of the ilium. POSTOPERATIVE MANAGEMENT: An early mobilization with weight bearing of both lower extremities as tolerated by the patient is allowed. Conventional radiographs for control of the position of the implants and fractures are taken after mobilization RESULTS: In all, 64 patients with FFP type II, FFP type III or FFP type IV were stabilized with a transacral bar osteosynthesis in the posterior pelvis. In 32 patients (50%), additional sacroiliac screws were inserted. In 29 patients (45.3%) the transsacral bar osteosynthesis was combined with a transpubic retrograde screw. Median length of hospital stay was 17.5 days. In all, 20 patients (31.3%) suffered general, 10 patients (15.6%) suffered surgery-related complications, and 41 patients (64.1%) were mobile in the room or on the ward at discharge. One-year mortality was 10.9%. The values of the SF­8 Physical and Mental Component Scores, Parker Mobility Score and Numeric Rating Scale were moderate, yet comparable with the values of patients of the same age.

Prospective assessment of key factors influencing treatment strategy and outcome of fragility fractures of the pelvis (FFP).

BACKGROUND: Fragility fractures of the pelvis (FFP) are a clinical entity with an increasing significance in clinical practice. Little is known about the conditions, which influence decision making and outcome. SETTING: Level I trauma center. MATERIAL AND METHODS: Prospective assessment of selected parameters of patients, who were admitted with a FFP in a 2-year period. Fractures were classified in accordance with the Rommens and Hofmann classification. Living environment, level of autonomy (independent walking), type of treatment (conservative versus operative), type of surgical technique, European Quality of Life-5 Dimensions-5 Levels (EQ-5D-5L), Short Form-8 Physical Component Score (SF-8 PCS) and Short Form-8 Mental Component Score (SF-8 MCS), Barthel Index, Parker Mobility Score (PMS) and Numeric Rating Scale (NRS) were collected at primary presentation (t1), at discharge (t2) and after 3 (t3) and 12 months (t4). Length of hospital stay, in-hospital complications, surgery-related complications, new osteoporotic fractures and mortality rate within the first year were also registered. The key factors influencing the choice of therapy and outcome were looked for. RESULTS: 110 patients, 99 women (90%) and 11 men (10%), were included in the study. Their mean age was 79.2 years (SD 10 years). Fourteen patients had FFP type I (12.7%), 59 FFP type II (53.6%), 11 FFP type III (10%) and 26 FFP type IV fractures (23.6%). All patients with FFP type I were treated conservatively. 48 patients with FFP types II-IV were treated conservatively and 48 operatively. Patients, who got a conservative outpatient treatment first and were hospitalized later, had higher FFP fracture types at admission. Operatively treated patients were hospitalized at a median of 33.5 days after the beginning of complaints, whereas the median day of admission of the conservative group was the day of trauma (p < 0.001). The operatively treated patients were hospitalized in a worse clinical condition (SF-8 PCS, EQ-5D-5L, autonomy). Length of stay (LoS) of operatively treated patients was significantly longer than of conservatively treated (p < 0.001). There was a tendency to more in-hospital complications in the operative group (p = 0.059). The rate of surgery-related complications (8.3%) was low with only one revision needed. Selected outcome parameters improved during the observation period nearly reaching the level before FFP after 1 year. SF-8 PCS, Barthel index and rate of patients living home were higher in the operative group at t4. The improvement of autonomy (independent walking) between t1 and t4 was significant in the operated group (p = 0.04) but not in the conservative group (p = 0.96). One-year mortality rate was 11.7% with no difference between the fracture types. One-year mortality rate of conservatively treated patients with FFP type II-IV was 13.5% versus 6.9% in the operative group (p = 0.38). CONCLUSION: Conservative treatment is appropriate in patients with FFP type I as well as in patients with FFP type II, provided that the last ones are hospitalized immediately after the traumatic event. Surgical treatment is recommended in patients with higher fracture types, with delayed presentation or after unsuccessful conservative treatment. In the conservative and operative group, all selected parameters considerably improved between t1 and t4 with a steeper increase in the operative group. The rate of postoperative complications is low. The 1-year mortality rate is the lowest in the operative group. Surgical stabilization of FFP is safe and reliable provided it is performed with care and in the appropriate target group.

Retrograde tibial nailing of far distal tibia fractures: a biomechanical evaluation of double- versus triple-distal interlocking.

OBJECTIVES: Retrograde tibial nailing using the Distal Tibia Nail (DTN) is a novel surgical option in the treatment of distal tibial fracture. Its unique retrograde insertion increases the range of surgical options in far distal fractures of the tibia beyond the use of plating. The aim of this study was to assess the feasibility of the DTN for far distal tibia fractures where only double rather than triple-distal locking is possible due to fracture localisation and morphology. METHODS: Six Sawbones® were instrumented with a DTN and an AO/OTA 43-A3 fracture simulated. Samples were tested in two configurations: first with distal triple locking, second with double locking by removing one distal screw. Samples were subjected to compressive (350 N, 600 N) and torsional (± 8 Nm) loads. Stiffness construct and interfragmentary movement were quantified and compared between double and triple-locking configurations. RESULTS: The removal of one distal screw resulted in a 60-70% preservation of compressive stiffness, and 90% preservation of torsional stiffness for double locking compared to triple locking. Interfragmentary movement remained minimal for both compressive and torsional loading. CONCLUSIONS: The DTN with a distal double locking can, therefore, be considered for far distal tibia fractures where nailing would be preferred over plating.

Plate fixation of the anterior pelvic ring in patients with fragility fractures of the pelvis.

INTRODUCTION: In fragility fractures of the pelvis (FFP), fractures of the posterior pelvic ring are nearly always combined with fractures of the anterior pelvic ring. When a surgical stabilization of the posterior pelvis is performed, a stabilization of the anterior pelvis is recommended as well. In this study, we aim at finding out whether conventional plate osteosynthesis is a valid option in patients with osteoporotic bone. MATERIALS AND METHODS: We retrospectively reviewed medical charts and radiographs of all patients with a FFP, who underwent a plate osteosynthesis of the anterior pelvic ring between 2009 and 2019. Patient demographics, fracture characteristics, properties of the osteosynthesis, complications and revision surgeries were documented. Single plate osteosynthesis (SPO) at the pelvic brim was compared with double plate osteosynthesis (DPO) with one plate at the pelvic brim and one plate anteriorly. We hypothesized that the number and severity of screw loosening (SL) or plate breakage in DPO are lower than in SPO. RESULTS: 48 patients with a mean age of 76.8 years were reviewed. In 37 cases, SPO was performed, in 11 cases DPO. Eight out of 11 DPO were performed in patients with FFP type III or FFP type IV. We performed significantly more DPO when the instability was located at the level of the pubic symphysis (p = 0.025). More patients with a chronic FFP (surgery more than one month after diagnosis) were treated with DPO (p = 0.07). Infra-acetabular screws were more often inserted in DPO (p = 0.056). Screw loosening (SL) was seen in the superior plate in 45% of patients. There was no SL in the anterior plate. There was SL in 19 of 37 patients with SPO and in 3 of 11 patients with DPO (p = 0.16). SL was localized near to the pubic symphysis in 19 of 22 patients after SPO and in all three patients after DPO. There was no SL in DPO within the first month postoperatively. We performed revision osteosynthesis in six patients (6/48), all belonged to the SPO group (6/37). The presence of a bone defect, unilateral or bilateral anterior pelvic ring fracture, post-operative weight-bearing restrictions, osteosynthesis of the posterior pelvic ring, and the presence of infra- or supra-acetabular screws did not significantly influence screw loosening in SPO or DPO. CONCLUSION: There is a high rate of SL in plate fixation of the anterior pelvic ring in FFP. In the vast majority, SL is located near to the pubic symphysis. DPO is associated with a lower rate of SL, less severe SL and a later onset of SL. Revision surgery is less likely in DPO. In FFP, we recommend DPO instead of SPO for fixation of fractures of the anterior pelvic ring, which are located in or near to the pubic symphysis.

Operative treatment of fragility fractures of the pelvis: a critical analysis of 140 patients.

BACKGROUND: Fragility fractures of the pelvis (FFP) are a clinical entity with an increasing frequency. Indications for and type of surgical treatment are still a matter of debate. PURPOSE: This retrospective study presents and critically analyses the results of operative treatment of 140 patients with FFP. SETTING: Level-I trauma center. MATERIALS AND METHODS: Demographic data, comorbidities, FFP-classification, type of surgical stabilization (percutaneous (P-group) versus open procedure (O-group)), length of hospital stay (LoS), general in-hospital complications, surgery-related complications, living environment before admission, mobility and destination at discharge were retracted from the medical and radiographic records. Patients were asked participating in a survey by telephone call about their quality of life. SF-8 Physical Component Score (PCS) and SF-8 Mental Component Score (MCS) were calculated as well as the Parker Mobility Score (PMS) and the Numeric Rating Scale (NRS). RESULTS: Mean age was 77.4 years and 89.3% of patients were female. 92.1% presented with one comorbidity, 49.3% with two or more comorbidities. Median length of hospital stay was 18 days, postoperative length of hospital stay was 12 days. 99 patients (70.7%) received a percutaneous operative procedure, 41 (29.3%) an open. Patients of the O-group had a significantly longer LoS than patients of the P-group (p = 0.009). There was no in-hospital mortality. There were significantly more surgery-related complications in the O-group (43.9%) than in the P-group (19.2%) (p = 0.006). Patients of the O-group needed more often surgical revisions (29.3%) than patients of the P-group (13.1%) (p = 0.02). Whereas 85.4% of all patients lived at home before admission, only 28.6% returned home at discharge (p < 0.001). The loss of mobility at discharge was not influenced by the FFP-classes (p = 0.47) or type of treatment (p = 0.13). One-year mortality was 9.7%. Mortality was not influenced by the FFP-classes (p = 0.428) or type of treatment (p = 0.831). Median follow-up was 40 months. SF-8 PCS and SF-8 MCS were moderate (32.43 resp. 54.42). PMS was 5 and NRS 4. Follow-up scores were not influenced by FFP-classes or type of treatment. CONCLUSION: Patients with FFP, who were treated operatively, suffered from a high rate of non-lethal general, in-hospital complications. Open surgical procedures induced more surgery-related complications and surgical revisions. Mental and physical follow-up scores are low to moderate. Condition at follow-up is not influenced by FFP-classes or type of treatment. Indications for operative treatment of FFP must be critically examined. Surgical fixation should obtain adequate stability, yet be as less invasive as possible. The advantages and limitations of different surgical techniques have to be critically evaluated in prospective studies.

Mechanical characterization of rose bengal and green light crosslinked collagen scaffolds for regenerative medicine.

Collagen is one of the most important biomaterials for tissue engineering approaches. Despite its excellent biocompatibility, it shows the non-negligible disadvantage of poor mechanical stability. Photochemical crosslinking with rose bengal and green light (RGX) is an appropriate method to improve this property. The development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated substances. In this study, we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior and mechanical behavior in micro tensile tests to obtain information on its wearing comfort (stiffness, strength and ductility). The mechanical stability of the collagen material after degradation due to cell contact is examined using thickness measurements. There is no linear increase or decrease due to layering homologous laminates. Unexpectedly, a decrease in elongation at break, Young's modulus and ultimate tensile strength are measured when the untreated monolayer is compared to the crosslinked one. Furthermore, we can detect a connection between stability and cell proliferation. The results show that with variation in number and type of layers, collagen scaffolds with tailored mechanical properties can be produced. Such a multi-layered structure enables the release of biomolecules into inner or outer layers for biomedical applications.