BACKGROUND/AIM:Anderson-D'Alonzo Type II odontoid fractures are common in the elderly and often treated surgically due to high nonunion rates and increased morbidity and mortality associated with conservative treatment. However, high rates of nonunion still occur with surgical treatment and specific fracture characteristics predicting nonunion remain unclear. This study aimed to identify morphological fracture features associated with nonunion in patients undergoing anterior screw osteosynthesis for Type II odontoid fractures. PATIENTS AND METHODS:In this retrospective study, 60 adult patients treated with two anterior fixations for Anderson-D'Alonzo Type II odontoid fractures at a Level 1 trauma center (2011-2019) were analyzed. Demographic, clinical, and radiographic data (time to surgery, use of 3D imaging, implant loosening, ASA class, age, sex, BMI, smoking status, Grauer classification, fracture angle, fracture dislocation angle, dislocation direction, dislocation distance, comminution, periarticular ossification or ankylosing spondilitis) were collected. Pre- and postoperative computed tomography (CT) scans were evaluated. Bony union status was determined at a minimum of six months follow-up. Statistical significance was set at α=0.05. RESULTS:Of the 60 patients (median age 80 years), 36 (60%) achieved bony union while 24 (40%) developed nonunion. Fracture angle was the only parameter significantly associated with nonunion (union median 27 vs. nonunion 40, p=0.049). No associations were found for age, sex, BMI, ASA class, smoking, surgical delay, Grauer type, displacement, comminution, or use of 3D imaging. CONCLUSION:Fracture angle is a significant predictor of nonunion in Type II odontoid fractures treated with anterior screw fixation. Preoperative assessment of fracture angle may aid in surgical decision-making and to optimize outcomes.

Intramedullary nailing is a common and safe procedure in the treatment of distal tibial shaft fractures. It is often accompanied with maltorsion of the tibia due to insufficient intraoperatively available and objective diagnostic tools. Therefore there´s high need for reliable tools for intraoperative torsional control. Radiographic parameters such as the Cortical Step Sign (CSS) and the Diameter Difference Sign (DSS) may serve for diagnosing relevant maltorsion intraoperatively. The aim of this study was to investigate the effect of maltorsion on CSS and DSS parameters in a distal tibial fracture model and to construct a prognostic model to detect maltorsion. A distal tibial shaft fracture (AO/OTA type “A”) was set on 19 human tibias. Torsion was gradually adjusted from 0° to 30° in external and internal torsion. Images were acquired with a C-arm in two planes and transferred to a PC for measurement of medial cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD) in a.p., and anterior cortical thickness (ACT), posterior cortical thickness (PCT), and transverse diameter (TD lat.) in lateral view of the proximal and distal fragment. For the various levels of torsion significant differences for each of the values of the examined variables could be shown. Highest visibility was found for ACT, TD a.p. and TD lat. Highest correlation of radiographic difference and maltorsion was found in internal torsion (TD lat./ TD a.p.). A threshold of less than 2 mm led to a probability to detect maltorsion of 0.7. ROC for the lateral model was better than for the a.p. model (0.866 vs. 0.829). TD lat. performed best regarding ROC in single parameter evaluation (0.778). Best prediction for relevant maltorsion was obtained with TD a.p. and TD lat. CSS and DSS are useful tools for detection of maltorsion in distal tibial shaft fractures. The parameters can be easily collected and therefore represent promising parameters for intraoperative torsional control.

BACKGROUND/AIM:Pedicle screw fixation is a standard technique for vertebral fractures but shows high loosening and pull-out rates, especially in osteoporotic bone. Cement augmentation can improve the screw-bone interface and construct stability. However, cement leakage rates of up to 94% have been reported, with rare but potentially serious complications such as pulmonary cement embolism. This study aimed to retrospectively evaluate the rate of cement leakage and serious complications after polymethylmethacrylate (PMMA)-augmented pedicle screw fixation. PATIENTS AND METHODS:We retrospectively reviewed 96 patients treated for thoracolumbar fractures with posterior stabilization and cement-augmented pedicle screws at LMU University Hospital Munich between July 2012 and August 2018. Demographic, operative, and imaging data were analyzed. Cement leakage detection rates were compared between intraoperative fluoroscopy, postoperative radiographs, and computed tomography. RESULTS:The cohort included 37 men (39%) and 59 women (61%). Most patients were ASA III (71%). Instrumentation involved two levels in 64% and four levels in 26% of cases. Mean operative time was 118±56 min. Cement leakage was identified in 71/93 patients (76%) on postoperative imaging. Intraoperative fluoroscopy detected leakage in 43% of cases, showing low sensitivity but high specificity. Postoperative radiographs detected leakage in 63%, while computed tomography showed the highest detection rate (91%). Increasing age was significantly associated with higher leakage risk (p=0.0109). CONCLUSION:Cement leakage after PMMA-augmented pedicle screw fixation is common on postoperative imaging but was not associated with serious clinical complications in this cohort. Intraoperative fluoroscopy detects less than half of leakages, indicating limited sensitivity. Advanced intraoperative imaging techniques such as 3D imaging may improve detection.

Abstract Background Patients affected by chronic kidney disease (CKD) are at increased risk of periprosthetic joint infection (PJI) after total hip arthroplasty (THA). This patient population has a higher risk of recurrent infections and hospitalization. The aim of this study is to compare the profile of microorganisms in patients with CKD and PJI of the hip versus controls and to individuate potentially unusual and drug-resistant microorganisms among the causative bacteria. Materials and methods A total of 4261 patients affected by PJI of the hip were retrospectively studied. Patients affected by CKD in this population were identified and compared with a control group of patients with PJI but without CKD. Data on patient characteristics and comorbidities were collected. The microorganisms responsible for PJI were identified and compared between both groups. Results The CKD group included 409 patients, 54.3% male, mean age of 73.8 ± 8.9 years, a higher body mass index (BMI) than the general population (29.88 ± 5.90 kg/m2), and higher age-adjusted CCI of 6.15 ± 2.35. Overall, 70 different isolates of microorganisms were identified, including 52 Gram-positive spp., 28 Gram-negative spp., 3 fungi, and 1 mycobacterium. Polymicrobial infections were more common in CKD group than controls (47.9% versus 30.9%; p < 0.0001). Staphylococcus spp. were the most common bacteria in both groups, followed by Gram-negative Enterobacteriaceae and Streptococcus spp. CKD group showed a higher risk of developing infections caused by Staphylococcus aureus (p = 0.003), Gram-negative bacteria, and Candida (p = 0.035). Conclusions Renal failure exposes patients who undergo THA to PJI caused by microorganisms that are potentially more drug resistant, leading to a higher risk of treatment failure. Knowing in advance the different microorganism profiles could help to plan a different surgical strategy. Level of Evidence III.

BACKGROUND AND OBJECTIVES:Surgical resection with microscopically negative margins constitutes one of the key elements of a curative therapeutic approach for localized sarcomas. However, the prognostic value of quantitative margin width remains controversial. We sought to determine the prognostic significance of margin status and margin width for local recurrence (LR), distant recurrence (DR), and overall survival. METHODS:Retrospective analysis of 210 patients undergoing resection of localized sarcoma between 1997 and 2018 at a national sarcoma reference center. RESULTS:Logistic regression did not reveal an effect of metric margin width as a prognostic factor for LR (odds ratio [OR] = 0.98, p = 0.574), DR (OR = 1, p = 0.908), or overall survival (hazard ratio = 0.98, 95% confidence interval = 0.73-1.20, p = 0.609). Subgroup analysis revealed no differences between complete first resections (R0) and re-resections (re-R0) following unplanned R1-resections for LR (p = 0.727) and overall survival (p = 0.125), but a significantly higher DR-rate in re-R0 cases (p = 0.022). CONCLUSIONS:Achieving a negative margin is essential in sarcoma surgery, however, metric margin width was not associated with disease-specific outcomes. Re-resection of unplanned R1-resections should be performed to control for LR and overall survival rates. As re-R0 cases were at significantly higher risk of DR, these patients should be followed up closely in standardized surveillance protocols.

Risk factors (RF) associated with aseptic loosening (AL) in total knee arthroplasty (TKA) are poorly understood. Therefore, the aim of this study was to investigate the anatomical shape variations in relation to the inner-diameter of the femur and the tibia as prognostic RF for AL of full hinge prosthesis (FHP) in primary and revision TKA. We retrospectively examined all patients, who underwent revision surgery (2003–2018) due to AL of the FHP in primary (n = 38) and revision TKA (n = 46). Diagnosis-appropriate controls without AL at minimum follow-up of 24 months were randomly collected for each group. Besides other risk factors, we also measured the inner diameter of the femur according to the Citak classification and of the tibia on anteroposterior radiographies. RF for AL are younger age in primary and revision as well as > 1 previous surgeries in revision TKA. The femoral index was shown to be a RF for AL in revision TKA (p = 0.001), but not in primary TKA. The novel tibial index was associated with AL in primary with AUC 0.776 (95% CI 0.67, 0.88), 65.8% sensitivity, 86.6% specificity and in revision TKA with AUC 0.817 (95% CI 0.73, 0.91), 82.6% sensitivity and 71.7% specificity. This is the first study to calculate the tibial measurements and the tibial index according to Citak et al. and to identify them as prognostic RF for AL of the full hinge knee prosthesis in TKA and confirm the femoral index as a RF for AL also in revision full hinge knee prosthesis. Therefore, the preoperative radiological evaluation should include the analysis of the anatomical shape variants in order to select the appropriate prosthesis design with a possibly enhanced prognosis.

Purpose This study aimed to investigate whether gait patterns of patients with fragility fractures of the pelvis (FFP) comply with the grade of fracture instability, defined by radiological patterns. Patients and methods This prospective, single-center, observational study included 39 patients with an FFP. Gait analysis was performed with a wearable insole force sensor (Loadsol® by Novel, Munich, Germany) 4–7 days after admission. Patients were divided in two groups: Group A included FFP type 1 fractures, which affect the anterior pelvic ring only, Group B contained FFP type 2–4 fractures with an involvement of the posterior pelvic ring. Primary outcome parameter was the FTI ratio (force–time integral (N*s)). Results The mean age was 85.08 years (SD ± 6.45), 94.9% (37/39) of the patients were female. The most common fracture type was an FFP 2b (64.1%, 25/39). Group A showed a significantly higher FTI ratio (45.12%, SD ± 4.19%) than Group B (38.45%, SD ± 5.97%, p = 0.002). Further, a significant correlation of the FTI ratio and the average ( r = 0.570, p < 0.001) and maximum ( r = 0.394, p = 0.013) peak force was observed. Conclusion The gait pattern of patients with an FFP type 2–4 was more imbalanced than of patients with an FFP type 1 fracture. These findings match with the radiological classification of FFP, which indicates higher instability, when the posterior pelvis is affected. Gait analysis might offer earlier functional diagnostics and may accelerate the treatment decision with shorter periods of immobility in future. Especially in cross-border cases, early gait analysis could be beneficial to clarify the indication for or against surgery.

BACKGROUND:In 2011, the European Foot and Ankle Society developed a Score (EFAS Score) to generate a standardized questionnaire for several European languages. The aim of this study is to analyse how the newly defined score correlates with already established function scores. METHODS:This study is a monocentric prospective study. The questionnaires were completed at least 12 months postoperatively at the same time point. All patients had undergone surgery with the Autologous Matrix-Induced Chondrogenesis® procedure for osteochondral lesions of the talus. RESULTS:A total of 69 patients (33 women, 36 men) participated in the study. The EFAS Score correlates very strongly with the Manchester-Oxford Foot Questionnaire (MOXFQ) and strongly with the Foot Function Index (FFI). CONCLUSION:This study shows that the EFAS Score correlates significantly with the FFI and the MOXFQ. The EFAS seems to be a more patient-friendly alternative due to fewer questions and response choices.

Even though an increased interest in the use of the EFAS Score (European Foot and Ankle Society) has been observed, no data comparing it with radiological findings has been presented in the literature. Accordingly, the aim of this study is to investigate how the post-operative integration of the AMIC® (autologous matrix-induced chondrogenesis)-membrane for osteochondral lesion of the talus using the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) - Score is related to the clinical satisfaction of the patients. A group of 24 patients aged between 17 and 63 (with a mean age of 35.7) were included at least 1 year post-operatively. They had all undergone an AMIC®-procedure of the talus. MRI findings using the MOCART Score were correlated to the EFAS Score at the same time point. Our main results showed no correlation between the MOCART-Score and the EFAS-Score (R = – 0.08). There was also no correlation between the MOCART-Score, the FFI-Score (Foot and Function Index) (R = 0.2) and the MOXFQ-Score (Manchester-Oxford Foot Questionnaire) (R = 0.12). There was no correlation between components of the MOCART-Score with the EFAS-Score (R between – 0.32 and 0.23). Our results question whether the MRI (a standard part of AMIC®-procedure-of-the-ankle post-operative follow-up) is still the most appropriate tool for post-operative control. They also offer a starting point for future discussion regarding the need for post-operative MRI and the use of other radiological diagnostics in relation to clinical satisfaction.

BACKGROUND:Posterior instrumentation using pedicle screws and rods is the most commonly used technique for the treatment of thoracolumbar fractures of the spine. The procedure aims to restore the neurologic and biomechanical functions of the spine and allows for early mobilization and rapid reintegration into society. It is unclear whether the magnitude of correction has an effect on postoperative outcomes.OBJECTIVE:We aimed to determine whether the magnitude of sagittal angular correction during posterior instrumentation of the spine had an effect on postoperative quality of life, pain and function outcomes as measured using the EQ5D-3L and the Core Outcome Measures Index (COMI) instruments. We also aimed to quantify the correlation between EQ5D-3L and COMI scores.METHODS:We analyzed the pre- and postoperative radiographs of 52 patients who underwent percutaneous pedicle screw placement for thoracolumbar fractures, as well as their self-reported EQ5D-3L and COMI quality of life, pain and functional outcome scores. Regression models were constructed to estimate the effect that the magnitude of Cobb angle correction had on postoperative outcomes. We also estimated the correlation between EQ5D-3L and COMI scores.RESULTS:The median EQ5D-3L TTO score was 0.9 (range, -0.1 to 1). The median COMI score was 3.1 (range, 0 to 10). There was no significant effect of the magnitude of correction on EQ5d-3L TTO scores (p= 0.3379; R= 0.36) or on COMI scores (p= 0.3379; R= 0.15). Age and bone mineral density were not found to be significant predictors of outcome (p= 0.05). There was a strong correlation between the EQ5D-3L TTO and COMI scores (r=-0.62).CONCLUSION:The magnitude of Cobb angle correction during pedicle screw instrumentation of thoracolumbar fractures did not influence quality of life, pain or function outcomes. There was good correlation between EQ5D-3L TTO scores and COMI scores.

Background/Aim: Open surgical reduction/fixation of thoracolumbar fractures results in significant soft-tissue trauma and related complications. Minimally-invasive technical developments could deliver similar radiological outcomes, while avoiding the related complications. We evaluated radiological and perioperative outcomes in thoracolumbar fractures by using a novel minimally-invasive device. Patients and Methods: Twenty-six patients with 29 thoracolumbar fractures using the NForce device were analyzed. Postoperative reduction and alignment were assessed by radiographic measurement of the local kyphosis angle (LKA) up until a follow-up period of 9 months. Results: Postoperative imaging revealed an average reduction of traumatic kyphosis of 8.25° (±7.72°) with an average postoperative LKA of 3.24° (±8.97°). The highest degree of reduction was 27.39°. The mean LKA had increased to 5.08° (±5.17°) at 3 months postoperative, 5.43° (±4.32°) at 6 months and 6.21° (±3.82°) at 9 months. Conclusion: The minimally invasive NForce system is effective in performing anatomic percutaneous reduction/fixation.

Elderly patients suffering from hip fractures are usually not able to fulfill postoperative weight-bearing restrictions. Therefore, the operative fixation construct has to be as stable as possible. Aim of the present study was to determine: (1) whether a therapeutic advantage could be achieved when using hip arthroplasty to treat acetabular fractures in geriatric patients; (2) whether an acetabular revision cup would be suitable for achieving fast postoperative mobilization and full weight-bearing; and (3) when a treatment with an uncemented hip revision cup for the primary fixation of osteoporotic acetabular fractures in geriatric patients is indicated. The functional outcome of THA using a reconstruction cup for an acetabular fracture was evaluated in ten patients using standardized scoring instruments. In addition, an analysis of the preexisting literature referring to total hip replacement in geriatric acetabular fractures was conducted and an algorithm for standardizing the treatment approach for geriatric patients with acetabular fractures was developed. The mean EQ-5D-3L quality of life score 0.7. The mean VAS score was 58.2. The average Barthel Index was 80.0 points [range: 0–100]. The mean HHS was 72.0 points, while the MHH Score yielded an average of 63.4 points. The average AP Score was 7.5. The literature analysis showed that total hip arthroplasty could be a feasible option for geriatric acetabular fractures. Primary hip arthroplasty using uncemented revision cup fixed with angular stable screws showed good results and is a feasible treatment option of acetabular fractures in geriatric patients. The approach is especially beneficial in patients with poor bone stock and allows postoperative full weight-bearing. The presented treatment algorithm could be a useful tool for identifying the most appropriate treatment option. IIb.

Periprosthetic joint infection is a serious disease with severe consequences for the patient's life. It is not known whether one-stage or two-stage replacement arthroplasty is superior. So far, there have been no studies on short-term complications between both surgical procedures. Therefore, we performed a retrospective study aiming to determine: 1) Does two-stage septic exchange arthroplasty have a higher short-term complication rate than one-stage? 2) Is there a difference in length of hospital stay and the in-hospital mortality rate between two- and one-stage septic exchange arthroplasty? Two-stage septic exchange arthroplasty has a higher short-term complication rate than one-stage. Retrospectively 429 patients who underwent a one- or two stage revision arthroplasty (288 hips and 141 knees) due to chronic PJI between January 2015 and December 2016 were recruited (one-stage: n = 385, two-stage: n = 44). Differences in postoperative complications, surgical therapy, ASA, Charlson Comorbidity Index (CCI), length of hospital, need for plastic surgery, pathogen, in-hospital morbidity and in-hospital mortality were compared using multiple logistic and Poisson regression. Regarding comorbidities, age, gender and BMI the groups were comparable. It was 3.5 times more likely to suffer from a medical complication if a two stage septic exchange was performed (OR 3.465, (95 % CI: 2.573 – 4.358) (p < 0.01)). In medical complications the two-stage group showed significantly more events (two-stage: 9 of 44= 20.5 %; one-stage: 30 of 385 = 7.8 % (p = 0.013)). The one-stage group showed more (not significant) nerve palsies after hip septic exchange. There was no difference in mortality between the groups (two-stage: 1/44= 2.3 %; one-stage: 3/385 = 0.8 % (p = 0.882)), the overall mortality was 0.93 %. The duration of hospital stay was 23.9 ± 19 days for the one-stage and 42.2 ± 17.7 days for the two-stage group (p < 0.001). We found that it is more likely to develop a medical complication after two-stage septic revision arthroplasty. There was no difference in overall surgical complications between the two surgical approaches. There was no difference in short-term mortality between the two techniques. III, retrospective case control study.

Aim Intramedullar nailing of tibial mid-shaft fractures is a common surgical treatment. Fracture reduction, however, remains challenging and maltorsion is a common discrepancy which aggravates functional impairment of gait and stability. The use of radiographic tools such as the cortical step sign (CSS) and the diameter difference sign (DDS) could improve fracture reduction. Therefore, the validity of the CSS and DDS was analyzed to facilitate detection of maltorsion in tibial mid-shaft fractures. Methods Tibial mid-shaft fractures were induced in human cadaveric tibiae according to the AO classification type A3. Torsional discrepancies from 0° to 30° in-/external direction were enforced after intramedullary nailing. Fluoroscopic-guided fracture reduction was assessed in two planes via analysis of the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD), anterior cortical thickness (ACT), posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and distal fracture fragment. Results The TD, LCT and ACT have shown a highly significant correlation to predict tibial maltorsion. While a model combining ACT, LCT, PCT and TD lateral was most suitable model to identify tibial maltorsion, a torsional discrepancy of 15°was most reliably detected with use of the TD and ACT. Conclusion The present study has shown, that maltorsion can be reliably assessed by the CSS and DDS during fluoroscopy. Thus, torsional discrepancies in tibial mid-shaft fractures can be most reliably assessed in the lateral plane by analysis of the LCT and TD.

BACKGROUND:The use of computer assisted surgery, navigation (NAV) in shoulder arthroplasty is still under discussion, regarding the clinical outcome and prosthesis longevity, especially when combining these factors with cost, time and surgeon's experience. Beside the NAV, there has been in use patient-specific instrumentation (PSI) as an additional tool for more precise glenoid implant position. Surgical NAV and PSI for glenoid implant positioning in anatomic and reverse total shoulder arthroplasty are in last years under observation and discussion.OBJECTIVE:To critically review and evaluate the current literature regarding the use of computer navigation and PSI in shoulder arthroplasty.METHODS:Critical review of the existing literature.RESULTS:Cost-effectiveness, prosthesis longevity and revision arthroplasty rate have not yet been proven clinically. Moreover, heterogeneity is high in studies that include different positioning systems (NAV, PSI and standard instrumentation). Heterogeneity is due to differences in surgical technique, implants, surgeon's expertise, radiographic image analysis technique.CONCLUSION:The use of navigation systems and PSI should be clinically proven in the shoulder arthroplasty. Independent experts' opinion and independent high level studies lack at the moment. There will be still a lot of talk regarding this topic in future.

A correction to this paper has been published: https://doi.org/10.1007/s11548-021-02348-7