[Navigated or conventional acetabular surgery : Comparison of positional accuracy exemplified by the infra-acetabular screw]. / Navigiert oder konventionell in der Acetabulumchirurgie : Vergleich der Positionsgenauigkeit am Beispiel der infraazetabulären Schraube.

BACKGROUND: The principle of joint-preserving treatment of acetabular fractures is the anatomic reduction of joint-bearing elements and internal osteosynthesis. For stabilization of the anterior and posterior columns against each other, the infra-acetabular screw (IAS) is regularly used in the clinical routine. OBJECTIVE: The aim of this study was to compare the position of the IAS in the infra-acetabular corridor after navigated placement and after freehand placement. MATERIAL AND METHOD: The position of the screw was evaluated in 42 patients using multiplanar reconstructions. The screw was placed freehand in 30 patients and using image-guided navigation in 12 patients. In addition to measurement of the position of the screw, demographic data, operating time, radiation exposure and blood loss were recorded. RESULTS: The vast majority of the patients were male (86%), the median age was 67 years and the median body mass index (BMI) was 25 kg/m2. The median operating time was 166 min and the median blood loss was 900 ml. The adjusted values in the whole sample considering the position of the screw were: distance of screw to cartilage mean value (m) = 3.8 mm, distance of screw to corridor center m = 3.5 mm and angle of screw to corridor m = 1.4°. There were no differences between the groups in the demographic parameters and the accuracy of positioning of the screw (p-value > 0.05). There was a longer irradiation time and a higher radiation dose in the navigated group compared to the group without navigation (p-value < 0.001). CONCLUSION: With appropriate experience both procedures are comparable taking into account the accuracy. Taking into consideration other perioperative parameters, such as radiation exposure and planned operating time, patient-related factors should be taken into consideration.

Treatment of Fracture-Related Infection after Pelvic Fracture.

BACKGROUND: The management of pelvic fractures is a significant challenge. Surgical site infection can result in the need for revision surgery, cause functional impairment, and lead to a prolonged length of stay and increased treatment costs. Although reports on fracture-related infection (FRI) after pelvic fracture fixation are sparsely reported in the literature, it is a serious complication. This study analysed patients with FRIs after pelvic fracture regarding patient characteristics, treatment strategies, and an evaluation of risk factors for FRI. METHODS: In this retrospective single-centre study, FRI was diagnosed based on clinical symptoms of infection and a positive culture of a bacterial infection. Depending on the severity and acuteness of the infection, osseous stabilization was restored either via implant retention (stable implant, no osteolysis), exchange (loose implant or bony defect), or external fixation (recurrence of infection after prior implant retaining revision). Healing of infection was defined as no sign of recurring infection upon clinical, radiological, and laboratory examination in the last follow-up visit. RESULTS: The FRI rate in our patient population was 7.5% (24/316). In 8/24 patients, the FRI occurred within the first three weeks after initial surgery (early) and 16/24 presented with a late onset of symptoms of FRI. A strategy of debridement, antibiotics, and implant retention (DAIR) was successful in 9/24 patients with FRI after pelvic fracture. A total of 10 patients required an exchange of osteo-synthetic implants, whereof three were exchanged to an external fixator. In five patients, we removed the implant because the fracture had already consolidated at the time of revision for infection. A total of 17/24 patients had a poly-microbial infection after a pelvic fracture and 3/24 patients died from post-traumatic multi-organ failure within the first 6 months after trauma. There were no cases of persistent infection within the remaining 21 patients. CONCLUSIONS: Although poly-microbial infection is common in FRI after pelvic fracture, the recurrence rate of infection is relatively low. A complex pelvic trauma with significant soft tissue injury is a risk factor for recurrent infection and multiple revisions. A strategy of DAIR can be successful in patients with a stable implant. In cases with recurrent infection or an unstable fracture site, the exchange of implants should be considered.

Epidemiology and injury morphology of traumatic hip dislocations in children and adolescents in Germany: a multi-centre study.

OBJECTIVE: Traumatic hip dislocations are very rare in childhood and adolescence. The aim of this multi-centre study is to analyse the current epidemiology and injury morphology of a large number of traumatic hip dislocations in children. This can provide a better understanding of childhood hip dislocations and contribute to the development of a therapeutic approach in order to prevent long-term impacts. METHODOLOGY: This retrospective, anonymised multi-centre study included patients, aged up to 17 years, with acute traumatic hip dislocations and open growth plates. The patients came from 16 German hospitals. Exclusion criteria included insufficient data, a positive history of hip dysplasia, or an association with syndromal, neurological or connective tissue diseases predisposing to hip dislocation. An analysis was carried out on the patients' anthropometric data and scans (X-ray, MRI, CT), which were collected between 1979 and 2021. Gender, age at the time of dislocation, associated fractures, mechanism of injury, initial treatment including time between dislocation and reduction, method of reduction, treatment algorithm following reduction and all documented complications and concomitant injuries were evaluated. RESULTS: Seventy-six patients met the inclusion criteria. There were two age peaks at 4-8 years and 11-15 years. There was an increased incidence of girls in the under-eight age group, who had mild trauma, and in the group of over-eights there were more boys, who had moderate and severe trauma. Dorsal dislocation occurred in 89.9% of cases. Mono-injuries dominated across all age groups. Concomitant injuries rarely occurred before the age of eight; however, they increased with increasing ossification of the acetabulum and appeared as avulsion injuries in 32% of 11-15-year-olds. Of the 76 patients, 4 underwent a spontaneous, 67 a closed and 5 a primary open reduction. A reduction was performed within 6 h on 84% of the children; however, in around 10% of cases a reduction was not performed until after 24 h. Concomitant injuries needing intervention were identified in 34 children following reduction. Complications included nerve irritation in the form of sensitivity disorders (n = 6) as well as avascular necrosis (AVN) of the femoral head in 15.8% of the patients (n = 12). CONCLUSIONS: Traumatic hip dislocations are rare in childhood and adolescence and have high complication rates. The most severe complication, femoral head necrosis, occurred in 16% of cases. Minor injuries, especially in younger children, are enough to cause a dislocation. Posterior dislocation was more frequent and primarily occurred as a mono-injury; however, concomitant injuries must be considered with increasing age. Children continue to experience delayed reductions. The length of time until reduction, age and the severity of the concomitant injury play a role in the development of femoral head necrosis; however, this topic requires additional investigation.

Therapy of a Chronically Infected Total Femur Prothesis in a 40-year-old Patient. / Therapie einer chronischen Infektion einer totalen Femurendoprothese bei einem 40-jährigen Patienten.

We report a case of a patient who was treated in 1999 at the age of 19 years with a proximal femur replacement due to Ewing sarcoma. After several infection-associated exchange procedures, the patient presented with a fistula and chronic infection of a total femur prosthesis in August 2019 at the age of 40 years. Interdisciplinary treatment with a 3-stage exchange procedure and implantation of a silver-coated total femur prosthesis was successfully performed and hip disarticulation could be avoided. After a follow-up of 2 years, the patient showed uneventful wound healing and full weight bearing without crutches.

Imaging, post-processing and navigation: Surgical applications in pelvic fracture treatment.

Technical advancements of the past decade have led to massive improvements regarding imaging and visualization in trauma care. Digital imaging technology has fundamentally changed most processes in fracture management. However, the digital revolution in trauma surgery has just begun. Optical tracking navigation is currently the gold standard for positioning of implants for advanced applications in trauma surgery. Digital technology may enable the surgeon to achieve the same level of safety even in non-navigated placement of screws: We developed a new planning tool to transcript a preoperative into a semi-transparent "fluoroscopic like" image that can be identified intraoperatively and used as a map for the safe placement of sacro-iliac screws based on the "vestibule concept". In the future, development of artificial intelligence algorithms may provide features like automated segmentation of bone-fragments and other applications for a systematic fracture analysis to improve the standard of care in trauma surgery. Digital transformation has massive impact on diagnostics and surgical management of pelvic fractures. Improved visualization technology provides a better understanding of the surgical anatomy of the pelvis and may enable the surgeon to achieve greatest safety in percutaneous placement of screws even without using optical tracking navigation tools. The "para-axial fusion technique" is a useful tool to plan fluoroscopic views based on a 3D dataset prior to the surgery.

Metabolic regulation by PD-1 signaling promotes long-lived quiescent CD8 T cell memory in mice.

Inhibitory signaling in dysfunctional CD8 T cells through the programmed cell death 1 (PD-1) axis is well established in chronic viral infections and cancers. PD-1 is also transiently induced to high concentrations during priming of acute infections and immunizations, yet its impact on the development of long-lived antigen-independent T cell memory remains unclear. In addition to its expected role in restraining clonal effector expansion, here, we show that PD-1 expression on antigen-specific CD8 T cells is required for the development of a durable CD8 T cell memory pool after antigen clearance. Loss of T cell­specific PD-1 signaling led to increased contraction and a defect in antigen-independent renewal of memory CD8 T cells in response to homeostatic cytokine signals, thus resulting in attrition of the memory pool over time. Whereas exhausted CD8 T cells regain function after PD-1 checkpoint blockade during chronic viral infection, the preexisting pool of resting functional bystander memory CD8 T cells established in response to a previously administered immunogen decreased. Metabolically, PD-1 signals were necessary for regulating the critical balance of mTOR-dependent anabolic glycolysis and fatty acid oxidation programs to meet the bioenergetic needs of quiescent CD8 T cell memory. These results define PD-1 as a key metabolic regulator of protective T cell immunity. Furthermore, these results have potential clinical implications for preexisting CD8 T cell memory during PD-1 checkpoint blockade therapy.

Surgical Drill Guide for Insertion of an Infra-Acetabular Screw Based on an Anatomically Precontoured Plate System: A Cadaveric Study.

PURPOSE: Due to the anatomic structure of the pelvis, free-hand placement of screws in the acetabular fracture management can be difficult. Infra-acetabular screw fixation increases acetabular stability by distal fixation of the cup. Aim of this cadaveric study is to investigate if a plate-referenced drill guide can provide save placement of an infra-acetabular screw over a precontoured suprapectineal quadrilateral buttress plate (SQBP). METHODS: We constructed a drill guide for an infra-acetabular screw based on the surface of an anatomically precontoured SQBP. A total of 12 adult cadaveric acetabular specimens were used for drill guide-assisted placement of the infra-acetabular screw. The drill guide contains a radiopaque spiral to allow longitudinal fine adjustment of the SQBP along the pelvic brim to assure correct position of the plate-drill-guide construct in relation to the Koehler's teardrop. After screw placement, we conducted a computed tomography (CT) scan of all specimens to assess the actual position of the screw in relation of the infra-acetabular corridor and the acetabular joint surface. RESULTS: The position of the screw was within the infra-acetabular corridor in all cases. We did not see any intra-articular or intrapelvic screw penetration. The mean distance of the centerline of the screw to the medial border of the infra-acetabular corridor was 3.35 mm. The secure distance to the virtual surface of the femoral head to was 7.3 mm. CONCLUSIONS: A plate-referenced drill guide can provide safe placement of an infra-acetabular screw for treatment of acetabular fractures. Radiographic fine adjustment is necessary to access the optimal entry point.

[Comparison of DRG revenues between fast and slow-track procedures for a two-stage replacement of prostheses for periprosthetic hip infections in the aG-DRG system 2020]. / Vergleich der DRG-Erlöse zwischen Fast- und Slow-Track-Verfahren beim zweizeitigen Prothesenwechsel bei periprothetischen Hüftinfektionen im aG-DRG-System 2020.

BACKGROUND: The treatment of periprosthetic hip infections is usually cost intensive, so it is generally not cost effective for hospitals. In chronic infections, a two-stage procedure is often indicated, which can be done as a fast-track procedure with a short prosthetic-free interim interval (2-4 weeks) or as a slow-track procedure with a long prosthetic-free interim interval (over 4 weeks). AIM: The aim of this study was to elucidate the revenue situation of both forms of treatment in the aG-DRG-System 2020, taking into account revenue-relevant influencing factors. METHODS: For fast-track and slow-track procedures with two-stage revision and detection of a staphylococcus aureus (MSSA), treatment cases were simulated using a grouper software (3M KODIP Suite) based on the diagnoses (ICD-10-GM) and procedures (OPS) and then grouped into DRGs. Revenue-relevant parameters, such as length of stay and secondary diagnoses (SD), were taken into account. In addition, two real treatment cases with fast-track and slow-track procedures were compared to each other. RESULTS: The total revenues for the slow-track procedure with a length of stay of 25 days (without SD) were 27,551 € and for a length of stay of 42 days (with SD) even 40,699 €, compared to 23,965 € with the fast-track procedure with a length of stay of 25 days (without SD) and 27,283 € for a length of stay of 42 days (with SD). The real treatment cases also showed a big difference in the total revenues of 12,244 € in favor of the slow-track procedure. DISCUSSION: Even in the aG-DRG-System 2020, the two-stage revision procedure with a long interim interval seems to be more interesting from a financial point of view and the hospital perspective compared to the fast-track procedure, especially with multimorbid patients. This creates a financial barrier to the treatment of such patients with a short interim interval.

Early functional treatment or trivialization? - current treatment strategies in lateral ligament injuries of the ankle.

Introduction: Ankle injuries are common in daily orthopaedic trauma practice, with a high incidence of lateral ligament complex (lat-lig-com) injuries of the ankle joint (AJ). Primarily, these lat-lig-com injuries heal sufficiently, although there is a risk of developing chronic ankle instability. However, there is a lack of knowledge about the clinical application and routine for rehabilitation strategies so as to prevent chronic instability. This study investigates the current rehabilitation concepts in clinical routine after ligament injuries of the AJ. Methods: Rehabilitation protocols, provided by orthopaedic and trauma surgery institutions in German speaking countries, were analysed in terms of weight-bearing, range of motion (ROM), physiotherapy and choice of orthosis. All protocols for operatively and non-operatively (nop) treated ligament ruptures of the AJ were included. Results: 120 of 213 institutions provided protocols of lat-lig-com injuries of the AJ. Regarding the orthosis, the nop-treatment group mainly used ankle braces; in contrast, the operative group preferred the use of an ankle boot. The operative group recommends 6-12 weeks for duration of orthosis in contrast to only 6 weeks in the nop group. Significant differences prevail in ROM, with free ROM in non-operative treatment from the first day after trauma (p<0.001) in contrast to a careful increase in ROM in the first 6 weeks post-operatively. Conclusion: Early functional treatment is clinical standard in rehabilitation after lat-lig-com injuries of the ankle. Regarding current literature the differences of restrictions in ROM and orthosis treatment after lat-lig-com injuries suggest a trivialization of conservative treatment in the first period after trauma compared to post-operative aftercare.

Comprehensive treatment algorithm for atlanto-axial rotatory fixation (AARF) in children.

BACKGROUND: Atlanto-axial rotatory fixation (AARF) is an uncommon condition in children presenting with torticollis. Many studies have elaborated on the diagnostic sequence of AARF. However, there is no consensus for the algorithm of management of AARF. METHODS: This study proposes to provide a comprehensive step-by-step guideline which aims to achieve and retain anatomic reduction of the atlanto-axial joint (AAJ). We recommend a 'therapeutic crescendo': closed reduction and immobilization in a rigid cervical collar (step I). In cases of re-dislocation, a second attempt of closed reduction and immobilization in a Halo-jacket (step II). Cases of recurrent dislocations due to persistent instability require open reduction and internal fixation. We present a new surgical technique of transverse suture transfixation (TSF) of C1/C2 (step III). Alternatively, a dorsal stabilization of C1/C2 is indicated after open reduction (step IV). 13 patients with radiologically confirmed AARF were included in this study. These patients were treated as per the above mentioned algorithm. All these patients were serially evaluated with a minimum follow-up of 1 year. RESULTS: Clinical data of 10/13 patients were available for follow-up evaluation at mean 4.6 years after the onset of symptoms. Two patients were managed surgically. We recorded good clinical results in all patients treated according to the algorithm. CONCLUSIONS: AARF is a subacute pediatric emergency. Reduction and maintenance of joint congruency of the AAJ are the treatment goals. The comprehensive therapeutic algorithm presented in this study is applicable in patients with AARF to achieve excellent long-term results. LEVEL OF EVIDENCE: IV, Retrospective cohort study. TRIAL REGISTRATION NUMBER: Clinical Trial Registry University of RegensburgZ-2014-0453-4. Registered 01 December 2014.

[PJI-TNM as new classification system for periprosthetic joint infections : An evaluation of 20 cases]. / PJI-TNM als neues Klassifikationssystem für Endoprotheseninfektionen : Eine Evaluation von 20 Fällen.

BACKGROUND: Current classifications for periprosthetic joint infections (PJIs) often lack a detailed description of the overall underlying situation of a patient. The PJI-TNM classification uses the principles of the TNM classification from oncology for the description of critical parameters in PJIs: affected joint, type of implant and implant stability, soft tissue conditions, maturity of biofilm formation, causative microorganism, comorbidities of the patient and recurrence of infection. The aim of the current work is to evaluate the feasibility of this new PJI-TNM classification in clinical practice. METHODS: The PJI-TNM classification was used in 20 patients with hip, knee and shoulder PJIs. Based on a retrospective chart review, the respective parameters T (tissue and implants), N (non-eukaryotic cells and fungi), M (morbidity) and r (reinfection) were classified for each case. RESULTS: All 20 cases (12 male, 8 female, average age 72.2 (40-88 years)) with 13 hip, 6 knee and 1 shoulder PJIs were to be classified with the new TNM-PJI classification system. There was a considerable heterogeneity among the cases: 12 protheses were fixed (T0), 6 were loosened (T1) and 2 were associated with a soft tissue defect (T2). Biofilm formation was considered immature in 7 cases (N0). Out of the PJIs, 13 were considered to be associated with mature biofilm formation. Out of the patients, 9 were systemically not or only mildly compromised (M0), 7 patients moderately (M1) and 3 patients (M2) severely compromised. One patient refused surgical treatment (M3a). Recurrent infections (r) were diagnosed in three cases. CONCLUSIONS: The principles of the TNM classification from oncology can also be used for the classification of PJIs. Despite the limited number of cases in this study, a considerable heterogeneity of the evaluated PJIs is shown, which is a phenomenon that is also known from clinical practice. This heterogeneity can be adequately addressed by this new classification, which might be beneficial in decision-making in the future.

Infographic: Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system.

Cite this article: Bone Joint Res. 2020;9(2):77-78.

Can the oncology classification system be used for prosthetic joint infection?: The PJI-TNM system.

Cite this article: Bone Joint Res. 2020;9(2):79-81.

Attenuation of Hypertrophy in Human MSCs via Treatment with a Retinoic Acid Receptor Inverse Agonist.

In vitro chondrogenically differentiated mesenchymal stem cells (MSCs) have a tendency to undergo hypertrophy, mirroring the fate of transient "chondrocytes" in the growth plate. As hypertrophy would result in ossification, this fact limits their use in cartilage tissue engineering applications. During limb development, retinoic acid receptor (RAR) signaling exerts an important influence on cell fate of mesenchymal progenitors. While retinoids foster hypertrophy, suppression of RAR signaling seems to be required for chondrogenic differentiation. Therefore, we hypothesized that treatment of chondrogenically differentiating hMSCs with the RAR inverse agonist, BMS204,493 (further named BMS), would attenuate hypertrophy. We induced hypertrophy in chondrogenic precultured MSC pellets by the addition of bone morphogenetic protein 4. Direct activation of the RAR pathway by application of the physiological RAR agonist retinoic acid (RA) further enhanced the hypertrophic phenotype. However, BMS treatment reduced hypertrophic conversion in hMSCs, shown by decreased cell size, number of hypertrophic cells, and collagen type X deposition in histological analyses. BMS effects were dependent on the time point of application and strongest after early treatment during chondrogenic precultivation. The possibility of modifing hypertrophic cartilage via attenuation of RAR signaling by BMS could be helpful in producing stable engineered tissue for cartilage regeneration.

Risk factor analysis for delayed union after subtrochanteric femur fracture: quality of reduction and valgization are the key to success.

BACKGROUND: Subtrochanteric femur fractures (SFF) are uncommon, but have a high complication rate concerning non-union and mechanical complications. There is ongoing discussion about risk factors for delayed fracture healing after SFF. The purpose of this study was to evaluate potential risk factors for delayed fracture healing after SFF. METHODS: This retrospective radio-morphometric case control study compares 61 patients after SFF in two groups (uncomplicated healing within 6 months postoperatively vs. delayed union) concerning radiographical properties. The patients were analyzed concerning the following parameter: Quality of the reduction according to Baumgaertner, CCD-angle, Tip-Apex Distance, leg-length shortening and fracture healing according to the RUSH Score. RESULTS: The mean RUSH-Score at 6 months postoperatively was 21.32(±4.57). At that point of time, only 29/61 fractures were radiographically fully consolidated (timely fracture healing) and 32 patients were rated as delayed union. The total revision rate was 9/61 (14.7%), whereof four patients required revision for symptomatic non-union of the SFF. The results of the radio-morphometric measurement showed a significant difference between both groups concerning the degree of reduction measured according to Baumgaertner (p = 0.022). The postoperative ipsilateral CCD-angle was different between the two groups (p = 0.019). After 12 months postoperatively, 48/61 (78.6%) of fractures were rated healed without any further intervention. CONCLUSIONS: Delayed union after SFF occurs frequently. In our patient population, the quality of reduction and the postoperative CCD-angle were the key factors to avoid delayed union. LEVEL OF EVIDENCE: Level III, Therapeutic study. TRIAL REGISTRATION: Clinical Trial Registry University of Regensburg Z-2018-1074-1. Registered 04. Aug 2018. https://studienanmeldung.zks-regensburg.de.

Comparative Study for Assessment of Functional Outcome of Intraarticular AO Type C Distal Humerus Fractures Treated by Parallel Plating.

BACKGROUND: Complex distal end of humerus fractures are one of the most challenging cases in orthopedics. There is a paucity of literature on outcomes of parallel reconstruction plates using olecranon osteotomy technique along with large sample size. This study focuses primarily on rate of various complications encountered in intraarticular AO Type C distal humerus fractures. MATERIALS AND METHODS: In this prospective study, we included 94 patients with isolated closed intraarticular AO type C distal and humerus injuries. Exclusion criteria were polytrauma, open injuries, and pathological fractures (except osteoporosis). The followup was done immediate postoperatively, 6 weeks, 6 months, 1 year and at 2 years. Range of motion (ROM), Mayo Elbow Performance Score (MEPS), and Disabilities of the Arm, Shoulder, and Hand (DASH) score was recorded at each visit. Assessment of union was done based on X-ray. Patients were classified into two groups; Group 1 - patients without complications (n = 64) and Group 2 - with one or more complications. RESULTS: The average duration of surgery was 2 h and 15 min. The complication rate was 31.9% (30/94), however, a total of 45 complications were noted. The difference between ROM in the two groups was statistically significant (P < 0.05), however, the difference between MEPS and DASH score was not statistically significant. The most common complication found was ulnar nerve neuropathy. CONCLUSION: Parallel plating using olecranon osteotomy is an acceptable approach for this fracture, but due to inherent nature of this injury, it has its own set of complications which must be counseled before surgery and active participation of patient is required to obtain realistic expectations and goals for the future.

Early functional rehabilitation after patellar dislocation-What procedures are daily routine in orthopedic surgery?

INTRODUCTION: Patellar dislocation and rupture of the medial patellofemoral ligament (MPFL) are frequently seen in daily orthopedic practice. Besides initial non-surgical treatment, surgery and subsequent rehabilitation are crucial for restoring stability in the femoropatellar joint. This study investigated current rehabilitation strategies after patellar dislocation because knowledge on this topic has been severely limited so far. MATERIALS AND METHODS: The current rehabilitation protocols of 42 orthopedic and trauma surgical institutions were analyzed regarding their recommendations on weight bearing, range of motion (ROM), and use of movement devices and orthosis. All protocols for conservative treatment and postoperative rehabilitation after MPFL reconstruction were compared. Descriptive and statistical analyses were carried out when appropriate. RESULTS: The different rehabilitation strategies for conservative and surgical treatment after patellar dislocation showed a tendency towards earlier functional rehabilitation after surgical MPFL reconstruction than after conservative treatment. Both surgical and conservative treatment involved initial restrictions in weight bearing, ROM, and use of movement devices and orthosis at the beginning of rehabilitation. The rehab protocols showed a significant earlier full weight bearing after surgical MPFL reconstruction (p > 0.001). Due to the presence of other parameters for early functional treatment, the absence of an indication for using orthosis (surgical: 44%, conservative: 33%; p = 0.515) or start of unlimited ROM of the knee (surgical: 4.9 weeks, conservative: 5.7 weeks; p = 0.076) showed by trend an earlier functional strategy after MPFL reconstruction than after conservative therapy. CONCLUSIONS: Both conservative and surgical treatment after patellar dislocation showed restrictions in the early phase of the rehabilitation. Earlier functional therapy was more common after MPFL reconstruction than after conservative treatment. Further clinical and biomechanical studies on rehabilitation strategies after patellar dislocation are needed to improve patient care und individualized therapy.

Clinical application of a minimally invasive cement-augmentable Schanz screw rod system to treat pelvic ring fractures.

PURPOSE: The purpose of this study is to analyze the results using the USS fracture MIS system (DePuy Synthes) to treat instable pelvic ring fractures. As its outstanding feature, it is the only Schanz screw and rod system at present that combines angular stability, perforation/fenestration of the screws for cement-augmentation, a variable screw length, and a large screw diameter. MATERIALS AND METHODS: Retrospective investigation of 134 pelvic ring fractures treated in 2012-2013. Twenty-five patients obtained the abovementioned implant. Besides baseline characteristics of the included patients and the surgical procedure, a clinical/radiological follow-up of six months was analyzed. RESULTS: Dividing the collective into two groups, I high-energy trauma and II fragility fracture of the pelvis, the following results were recorded: group I: ten patients, six male, age 48.4 ± 19.7 years. Mean ISS 41 ± 22.5, fracture classification: AO/OTA type 61 B1/C1/C3 = 1/5/4. Operative treatment: three transiliac internal fixator, seven iliolumbar fixation, one implant was cement-augmented. Group II: 15 patients, 14 female, age 77.5 ± 10.1 years. Fracture classification according to Rommens: FFPII/III/IV = 6/1/8. Operative treatment: eight transiliac internal fixator, seven iliolumbar fixation, 14 implants were cement-augmented. Overall surgical side complications: 16%. Radiological examination: correct positioning of all ilium screws. Follow-up after six month (16 patients): all showed fracture consolidation. One ilium screw was broken close to the connecting clamp. CONCLUSION: The investigated Schanz screw rod system is a suitable implant to broaden the established procedures to stabilize dorsal pelvic ring fractures. TRIAL REGISTRATION: The study is registered at the Clinical Trial Registry University of Regensburg (Number Z-2017-0878-3).

Programming of CD8 T Cell Quantity and Polyfunctionality by Direct IL-1 Signals.

IL-1, generally considered an amplifier of adaptive immune responses, has been proposed for use as adjuvant during immunization with weak immunogens. However, its effects on memory T cell function remain largely undefined. Using the murine model of acute viral infection, in this paper, we show that in addition to augmenting the size of the Ag-specific pool, IL-1 signals act directly on CD8 T cells to promote the quality of effector and memory responses. Ablation of IL-1R1 or MyD88 signaling in T cells led to functional impairment; both the ability to produce multiple cytokines on a per cell basis (polyfunctionality) and the potential for recall proliferation in response to antigenic restimulation were compromised. IL-1 supplementation during priming augmented the expansion of Ag-specific CD8 T cells through the MyD88-IRAK1/4 axis, resulting in a larger memory pool capable of robust secondary expansion in response to rechallange. Together, these findings demonstrate a critical role of the IL-1-MyD88 axis in programming the quantity and quality of memory CD8 T cell responses and support the notion that IL-1 supplementation may be exploited to enhance adoptive T cell therapies against cancers and chronic infections.

A guideline for placement of an infra-acetabular screw based on anatomic landmarks via an intra-pelvic approach.

BACKGROUND: Due to demographic changes, more and more fracture patterns involving anterior acetabular structures occur. The infra-acetabular screw is seen a useful tool to increase stability in fixation of the acetabular cup. However, the exact position of this screw in relation to anatomic landmarks which are intra-operatively palpable via an intra-pelvic approach has not yet been determined. METHODS: This biomorphometric experimental study references the ideal screw position of an infra-acetabular screw to anatomic landmarks palpable via an intra-pelvic approach. Therefore, we created a computer tomography-based 3D-model of 40 patients (20 women, 20 men) who received a computer tomography (CT) scan of the pelvis for any other reason than an acetabular fracture. RESULTS: The entry point of an ideal infra-acetabular was of high constancy. At mean, this point was 10.2 mm caudal and 10.4 mm medial of the ilio-pubic/ilio-pectineal eminence. This reference is independent of age, gender, or physical dimensions. However, we found gender-dependent differences for the angulation and the length of the screw. CONCLUSIONS: This study provides a comprehensive guideline to determine the ideal entry point for an infra-acetabular screw via an intra-pelvic approach. The entry point is located 10.2 mm caudal and 10.4 mm medial of the ilio-pubic/ilio-pectineal eminence. TRIAL REGISTRATION: Clinical Trial Registry University of Regensburg Z-2017-0930-1 . Registered 04. Dec 2017.