Mechanical and histological properties of native medial menisci compared to allograph medial menisci in the osteoarthritic knee.

This study was designed to provide information on how the menisci change over the course of osteoarthritis, particularly with regard to their mechanical properties. The aim was to determine the difference between healthy menisci (fresh frozen meniscal transplants) and menisci harvested during total knee arthroplasty. The latter allows the grading of age-related and osteoarthritic changes in the menisci on macroscopic and microscopic levels. A total of 10 menisci from arthritic knee joints (medial) harvested during total knee arthroplasty were used and compared with 10 medial fresh frozen meniscal transplants. The mechanical measurements were carried out on a Mach-1 testing machine using indentation testing to determine the instantaneous modulus and the thickness of the menisci. The specimens were then embedded in paraffin, sectioned on a microtome, and stained with hematoxylin-eosin and safranin-O. All measurements were divided into the anterior horn, pars intermedia, and posterior horn. There was no significant difference in the instantaneous modulus for the posterior horn in the fresh frozen menisci with 0.27 ± 0.1 MPa compared to the arthritic menisci with 0.18 ± 0.03 MPa. No significant difference could be determined for the meniscus thicknesses. There was a significant difference in the safranin-O staining. There were also significant differences in the Pauli score: the arthrosis menisci showed a sum score that was, on average, four times higher than the sum score of the fresh frozen menisci. In the present study, it could be shown very well that there are significant differences in the mechanical properties as well as in the macroscopic and histopathological scores, such as the Pauli score, between the fresh frozen meniscus allografts considered healthy and osteoarthritic menisci resulting from total knee arthroplasty. With a degradation score of 3 (Pauli), the instantaneous modulus was reduced by more than 50% compared to healthy controls. More importantly, however, the fresh frozen menisci only show a grade 2 when converting the sum values into grades, where a grade 2 indicates slight degeneration. This is interesting because fresh frozen meniscus transplants were always considered healthy in previous publications and should, therefore, actually have a grade 1.

Response of Articular Cartilage to Hyperosmolar Stress: Report of an Ex Vivo Injury Model.

BACKGROUND: Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs. PURPOSE: To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium. RESULTS: The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3. CONCLUSION: This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury. CLINICAL RELEVANCE: Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.

Non-unions and wound infections do not differ following intramedullary nailing and plate osteosynthesis for distal third femur fractures: a meta-analysis.

Purpose: The fixation method of distal, extra-articular femur fractures is a controversially discussed. To ensure better stability itself, earlier mobilization and to prevent blood loss - all these are justifications for addressing the femur via reamed intramedullary nailing (RIMN). Anatomical reposition of multifragmentary fractures followed by increased risks of non-union are compelling reasons against it. The purpose of this study was to systematically review the literature for rates of non-union and wound infection, as well as blood loss and time of surgery. Methods: According to the PRISMA guidelines we conducted this systematic review by searching the Cochrane, PubMed, Ovid, MedLine, and Embase databases. Inclusion criteria were the modified Coleman methodology score (mCMS) >60, age >18 years, and extra-articular fractures of the distal femur. Biomechanical and animal studies were excluded. By referring to title and abstract relevant articles were reviewed independently. In the consecutive meta-analysis, we compared 9 studies and 639 patients. Results: There is no statistically significant difference comparing superficial wound infections when RIMN was performed (OR = 0.50; 95% CI: 0.18 - 1.42; P = 0.19) as well as in deep wound infections (OR = 0.74; 95% CI: 0.19-2.81; P = 0.62). However, these results were not significant. We also calculated for potential differences in the rate of non-unions depending on the surgical treatment applied. Data of 556 patients revealed an overall number of 43 non-unions. There was no significant difference in rate of non-unions between both groups (OR = 0.97; 95% CI: 0.51-1.85; P = 0.92). Conclusion: No statistical difference was found in our study among RIMN and plate fixation in the treatment of distal femoral fractures with regard to the incidence of non-union and wound infections. Therefore, the indication for RIMN or plating should be made individually and based on the surgeon's experience.

Validation of a Finite Element Simulation for Predicting Individual Knee Joint Kinematics.

Goal: We introduce an in-vivo validated finite element (FE) simulation approach for predicting individual knee joint kinematics. Our vision is to improve clinicians' understanding of the complex individual anatomy and potential pathologies to improve treatment and restore physiological joint kinematics. Methods: Our 3D FE modeling approach for individual human knee joints is based on segmentation of anatomical structures extracted from routine static magnetic resonance (MR) images. We validate the predictive abilities of our model using static MR images of the knees of eleven healthy volunteers in dedicated knee poses, which are achieved using a customized MR-compatible pneumatic loading device. Results: Our FE simulations reach an average translational accuracy of 2 mm and an average angular accuracy of 1[Formula: see text] compared to the reference knee pose. Conclusions: Reaching high accuracy, our individual FE model can be used in the decision-making process to restore knee joint stability and functionality after various knee injuries.

Major lower extremity amputations - risk of re-amputation, time to re-amputation, and risk factors: a nationwide cohort study from Denmark.

BACKGROUND AND PURPOSE: Re-amputation after lower extremity amputation is frequent. The primary aim of our study was to investigate cumulative re-amputation risk after transtibial amputation (TTA), knee disarticulation (KD), and transfemoral amputation (TFA) and secondarily to investigate time to re-amputation, and risk factors. METHODS: This observational cohort study was based on data from the Danish Nationwide Health registers. The population included first-time major lower extremity amputations (MLEA) performed in patients ≥ 50 years between 2010 and 2021. Both left and right sided MLEA from the same patient were included as index procedures. RESULTS: 11,743 index MLEAs on 10,052 patients were included. The overall cumulative risks for re-amputation were 29% (95% confidence interval [CI] 27-30), 30% (CI 26-35), and 11% (CI 10-12) for TTA, KD, and TFA, respectively. 58% of re-amputations were performed within 30 days after index MLEA. Risk factors for re-amputation within 30 days were dyslipidemia (hazard ratio [HR] 1.2, CI 1.0-1.3), renal insufficiency (HR 1.2, CI 1.1-1.4), and prior vascular surgery (HR 1.3, CI 1.2-1.5). CONCLUSION: The risk of re-amputation was more than twice as high after TTA (29%) and KD (30%) compared with TFA (11%). Most re-amputations were conducted within 30 days of the index MLEA. Dyslipidemia, renal insufficiency, and prior vascular surgery were associated with higher risk of re-amputation.

Internal Rotation Measurement of the Knee with Polymer-Based Capacitive Strain Gauges versus Mechanical Rotation Measurement Taking Gender Differences into Account: A Comparative Analysis.

With the conventional mechanical rotation measurement of joints, only static measurements are possible with the patient at rest. In the future, it would be interesting to carry out dynamic rotation measurements, for example, when walking or participating in sports. Therefore, a measurement method with an elastic polymer-based capacitive measuring system was developed and validated. In our system, the measurement setup was comprised of a capacitive strain gauge made from a polymer, which was connected to a flexible printed circuit board. The electronics integrated into the printed circuit board allowed data acquisition and transmission. As the sensor strip was elongated, it caused a change in the spacing between the strain gauge's electrodes, leading to a modification in capacitance. Consequently, this alteration in capacitance enabled the measurement of strain. The measurement system was affixed to the knee by adhering the sensor to the skin in alignment with the anterolateral ligament (ALL), allowing the lower part of the sensor (made of silicone) and the circuit board to be in direct contact with the knee's surface. It is important to note that the sensor should be attached without any prior stretching. To validate the system, an in vivo test was conducted on 10 healthy volunteers. The dorsiflexion of the ankle was set at 2 Nm using a torque meter to eliminate any rotational laxity in the ankle. A strain gauge sensor was affixed to the Gerdii's tubercle along the course of the anterolateral ligament, just beneath the lateral epicondyle of the thigh. In three successive measurements, the internal rotation of the foot and, consequently, the lower leg was quantified with a 2 Nm torque. The alteration in the stretch mark's length was then compared to the measured internal rotation angle using the static measuring device. A statistically significant difference between genders emerged in the internal rotation range of the knee (p = 0.003), with female participants displaying a greater range of rotation compared to their male counterparts. The polymer-based capacitive strain gauge exhibited consistent linearity across all measurements, remaining within the sensor's initial 20% strain range. The comparison between length change and the knee's internal rotation angle revealed a positive correlation (r = 1, p < 0.01). The current study shows that elastic polymer-based capacitive strain gauges are a reliable instrument for the internal rotation measurement of the knee. This will allow dynamic measurements in the future under many different settings. In addition, significant gender differences in the internal rotation angle were seen.

Effect of Vancomycin, Gentamicin and Clindamycin on Cartilage Cells In Vitro.

BACKGROUND: The treatment of grafts with vancomycin for ligament reconstruction in knee surgery is the current standard. However, high antibiotic concentrations have chondrotoxic effects. PURPOSE: To test the chondrotoxicity of clindamycin, gentamicin and vancomycin in comparable concentrations. In vitro and in vivo effective concentrations hugely vary from drug to drug. To allow for comparisons between these three commonly used antibiotics, the concentration ranges frequently used in orthopedic surgical settings were tested. STUDY DESIGN: Controlled laboratory study. METHODS: Human cartilage from 10 specimens was used to isolate chondrocytes. The chondrocytes were treated with clindamycin (1 mg/mL and 0.5 mg/mL), gentamicin (10 mg/mL and 5 mg/mL) or vancomycin (10 mg/mL and 5 mg/mL), at concentrations used for preoperative infection prophylaxis in ligament surgery. Observations were taken over a period of 7 days. A control of untreated chondrocytes was included. To test the chondrotoxicity, a lactate dehydrogenase (LDH) test and a water-soluble tetrazolium salt (WST-1) assay were performed on days 1, 3 and 7. In addition, microscopic examinations were performed after fluorescence staining of the cells at the same time intervals. RESULTS: All samples showed a reasonable vitality of the cartilage cells after 72 h. However, clindamycin and gentamicin both showed higher chondrotoxicity in all investigations compared to vancomycin. After a period of 7 days, only chondrocytes treated with vancomycin showed reasonable vitality. CONCLUSIONS: The preoperative treatment of ligament grafts with vancomycin is the most reasonable method for infection prophylaxis, in accordance with the current study results regarding chondrotoxicity; however, clindamycin and gentamicin cover a wider anti-bacterial spectrum. CLINICAL RELEVANCE: The prophylactic antibiotic treatment of ligament grafts at concentrations of 5 mg/mL or 10 mg/mL vancomycin is justifiable and reasonable. In specific cases, even the use of gentamicin and clindamycin is appropriate.

Influence of the COVID-19 Pandemic on Musculoskeletal Complaints and Psychological Well-Being of Employees in Public Services-A Cohort Study.

BACKGROUND: The COVID-19 pandemic resulted in unprecedented restrictions on public and private life. The aim of the study was to investigate the impact of the COVID-19 pandemic on the physical and mental health of employees in the public sector, especially patient-related professions. METHODS: For the data collection in summer 2021, an online questionnaire was used. Compared to a pre-pandemic point of time, the prevalence, frequency, and intensity of musculoskeletal pain, mental well-being, health status, and quality of life were recorded. RESULTS: The questionnaire was completed by 1678 employees (f: 1045, m: 617). A total of 1504 employees (89.6%) were affected by complaints. Compared to before the pandemic, the prevalence and intensity of musculoskeletal complaints and psychological distress increased significantly. Patient-related professions (n = 204) showed significantly higher levels of stress and discomfort in several aspects (p < 0.05). CONCLUSIONS: Due to the COVID-19 pandemic, there was an increase in musculoskeletal complaints and a decrease in psychological well-being. Preventive factors related to mental health were identified as male gender, a middle- to older-age group, employees with children, and working from home. Attention should be drawn to these findings and prevention strategies should be brought into focus to strengthen the employees' health. Special focus should be drawn to patient-related professions who are particularly confronted with pandemic-associated challenges.

[Influence of the quadriceps muscles on the patellofemoral contact in patients with low flexion patellofemoral instability after MPFL reconstruction]. / Einfluss der Quadrizepsmuskulatur auf den patellofemoralen Kontaktmechanismus bei Patienten mit strecknaher patellofemoraler Instabilität nach MPFL-Rekonstruktion.

INTRODUCTION: MPFL reconstruction represents one of the most important surgical treatment options for recurrent patellar dislocations at low flexion angles associated with low flexion patellofemoral instability. Nevertheless, the role of quadriceps muscles in patients with patellofemoral instability before and after patellofemoral stabilization using MPFL reconstruction has not been fully elucidated. The present study investigates the influence of quadriceps muscles on the patellofemoral contact in patients with low flexion patellofemoral instability (PFI) before and after surgical patellofemoral stabilization using MPFL reconstruction using 3 T MRI datasets in early degrees of flexion (0-30°). METHODS: In this prospective cohort study, 15 patients with low flexion PFI before and after MPFL reconstruction and 15 subjects with healthy knee joints were studied using dynamic MRI scans. MRI scans were performed in a custom-made pneumatic knee loading device to determine the patellofemoral cartilage contact area (CCA) with and without quadriceps activation (50 N). Comparative measurements were performed using 3D cartilage and bone meshes in 0-30° knee flexion in the patients with patellofemoral instability preoperatively and postoperatively. RESULTS: The preoperative patellofemoral CCA of patients with low flexion PFI was 67.3 ± 47.3 mm2 in 0° flexion, 118.9 ± 56.6 mm2 in 15° flexion, and 267.6 ± 96.1 mm2 in 30° flexion. With activated quadriceps muscles (50 N), the contact area was 72.4 ± 45.9 mm2 in extension, 112.5 ± 54.9 mm2 in 15° flexion, and 286.1 ± 92.7 mm2 in 30° flexion without statistical significance. Postoperatively determined CCA revealed 159.3 ± 51.4 mm2 , 189.6 ± 62.2 mm2 and 347.3 ± 52.1 mm2 in 0°, 15° and 30° flexion. Quadriceps activation with 50 N showed a contact area in extension of 141.0 ± 63.8 mm2, 206.6 ± 67.7 mm2 in 15° flexion, and 353.5 ± 64.6 mm2 in 30° flexion, also without statistical difference compared with unloaded CCAs. Subjects with healthy knee joints showed an increase of 10.3% in CCA at 30° of flexion (p = 0.003). CONCLUSION: Although patellofemoral CCA increases significantly after isolated MPFL reconstruction in patients with low flexion patellofemoral instability, there is no significant influence of quadriceps muscles either preoperatively or postoperatively.

Digital measurement of anterolateral knee laxity using strain sensors.

PURPOSE: The ambition of the research group was to develop a sensor-based system that allowed the transfer of results with strain sensors applied to the knee joint. This system was to be validated in comparison to the current static mechanical measurement system. For this purpose, the internal rotation laxity of the knee joint was measured, as it is relevant for anterolateral knee laxity and anterior cruciate ligament (ACL) injury. METHODS: This is a noninvasive measurement method using strain sensors which are applied to the skin in the course of the anterolateral ligament. The subjects were placed in supine position. First the left and then the right leg were clinically examined sequentially and documented by means of an examination form. 11 subjects aged 21 to 45 years, 5 women and 6 men were examined. Internal rotation of the lower leg was performed with a torque of 2 Nm at a knee flexion angle of 30°. RESULTS: Comparison of correlation between length change and internal knee rotation angle showed a strong positive correlation (r = 1, p < 0.01). Whereas females showed a significant higher laxity vs. males (p = 0.003). CONCLUSIONS: The present study showed that the capacitive strain sensors can be used for reproducible measurement of anterolateral knee laxity. In contrast to the previous static systems, a dynamic measurement will be possible by this method in the future.

Composite material consisting of microporous beta-TCP ceramic and alginate-dialdehyde-gelatin for controlled dual release of clindamycin and bone morphogenetic protein 2.

The aim of this study was to produce a composite of microporous ß-TCP filled with alginate-gelatin crosslinked hydrogel, clindamycin and bone morphogenetic protein (BMP-2) to prolong the drug-release behaviour for up to 28 days. The most promising alginate-di-aldehyde(ADA)-gelatin gel for drug release from microcapsules was used to fill microporous ß-TCP ceramics under directional flow in a special loading chamber. Dual release of clindamycin and BMP-2 was measured on days 1, 2, 3, 6, 9, 14, 21 and 28 by high performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA). After release, the microbial efficacy of the clindamycin was checked and the biocompatibility of the composite was tested in cell culture. Clindamycin and the model substance FITC-protein A were released from microcapsules over 28 days. The clindamycin burst release was 43 ± 1%. For the loaded ceramics, a clindamycin release above the minimal inhibitory concentration (MIC) until day 9 and a burst release of 90.56 ± 2.96% were detected. BMP-2 was released from the loaded ceramics in low concentrations over 28 days. The release of active substances from ß-TCP and hydrogel have already been extensively studied. Directional flow loading is a special procedure in which the ceramic could act as a stabilizer in the bone and, as a biodegradable system, enables a single-stage surgical procedure. Whether ADA-gelatin gel is suitable for this procedure as a more biodegradable alternative to pure alginate or whether a dual release is possible in this composite has not yet been investigated.

Fractures in Childhood and Young Adulthood According to Maternal Smoking in Late Pregnancy. A Danish Cohort Study.

BACKGROUND: Fractures account for the most frequent cause of hospitalization during childhood and numbers have increased over time. Of all fractures in childhood and young adulthood, 66% are recurrent fractures, suggesting that some people are predestined for fractures. The aim of this study was to investigate the association between maternal smoking during late pregnancy and the risk of fractures in the children. METHODS: The study included 11,082 mothers and their children from the cohort "Healthy Habits for Two" born between 1984 and 1987. Information about maternal smoking during pregnancy came from questionnaires filled out in pregnancy, while information about fractures was derived from the Danish National Patient Registry. Over a follow-up of 24 years (1994-2018), Cox regression with multiple failures was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for fractures in childhood and young adulthood according to maternal smoking in late pregnancy. Information about body mass index (BMI) and smoking status in young adulthood was included as time variant covariates. RESULTS: During an age span of 8-32 years, 6,420 fractures were observed. Of the mothers, 39.1% smoked during late pregnancy. Compared to children of mothers who did not smoke, children of mothers who smoked 1-9 cigarettes per day and 10+ cigarettes per day had an increased risk of fractures (HR 1.14 [CI: 1.06; 1.21] and HR 1.14 [CI: 1.07; 1.22], respectively). After adjusting for BMI and smoking status in young adulthood, the findings were slightly strengthened, showing an increased risk of fractures of 23 and 25% in children of mothers smoking 1-9 cigarettes per day and 10+ cigarettes per day, respectively. CONCLUSION: Maternal smoking during late pregnancy was associated with a higher risk of fractures in the child. This result indicates that exposure to cigarette smoke in utero may play a role in lifelong bone health.

Effect of 20 µm thin ceramic coatings of hydroxyapatite, bioglass, GB14 and Beta-Tricalciumphosphate with copper on the biomechanical stability of femoral implants.

In the present work, we test four thin coatings for titanium implants, namely, bioglass, GB14, Beta-Tricalciumphosphate (ß-TCP) and hydroxyapatite (HA) with and without incorporated copper ions for their osteointegrative capacity. A rabbit drill hole model for time intervals up to 24 weeks was used in this study. Implant fixation was evaluated by measuring shear strength of the implant/bone interface. Quantitative histological analysis was performed for the measurements of bone contact area. Implants with and without copper ions were compared after 24 weeks. Thin coatings of GB14, HA or TCP on titanium implants demonstrated high shear strength during the entire test period of up to 24 weeks. Results confirmed osteointegrative properties of the coatings and did not reveal any negative effect of copper ions on osteointegration. The integration of copper in degradable osteoconductive coatings with a thickness of approx. 20 µm represents a promising method of achieving antibacterial shielding during the entire period of bone healing while at the same time improving osteointegration of the implants.

Development and validation of a questionnaire to measure the severity of pain, functional limitations, and reduction of sports ability for german-speaking patients with osteochondral lesions of the ankle (OCLA-G).

BACKGROUND: There is no patient-reported functional scale specific for osteochondral lesion of the ankle (OCLA). Therefore, the objectives of this study were to develop a questionnaire that measures symptom severity, function, and sports capacity in patients with osteochondral lesions of the ankle and to determine the psychometric properties of the tool in German language (OCLA-G). METHODS: The OCLA-G questionnaire was developed according to the COSMIN guidelines. Scalable items were generated from a literature search, based on an evaluation of 71 own OCLA patients, and from expert opinions. Following a twofold item reduction the questionnaire underwent explorative data analysis and principal component analysis. Validity and reliability were analysed in four groups of participants (40 patients with OCLA, 40 patients with other foot and ankle injuries, 40 asymptomatic athletes serving as a population at risk, and 40 asymptomatic persons playing sports not at risk). The minimum age for participation in the study was set at 18 years. The mean age was 39.3 ± 15.1 years. RESULTS: The final OCLA-G questionnaire consists of eight and five questions to mirror activities of daily life (ADL) and sports, respectively. Excellent internal consistency (Cronbach's α = 0.950 for the ADL subscore and 0.965 for the sport subscale, respectively) was found. Spearman's rank correlation coefficients for test-retest reliability were 0.992 for the ADL subscore and 0.999 for the sport subscale (p < 0.001). The results of the exploratory and confirmatory factor analyses indicated that item difficulty was between 23.4 and 62.8. The Pearson correlation for the OCLA subscales ADL and sport was 0.853 (p < 0.001). Construct validity as tested against the SF-12 questionnaire subscales (Physical and Mental component scale) were r = -0.164 to -0.663 (p < 0.05). Statistically, there was no ADL and sport OCLA mean score difference between OCLA patients and patients with other foot and ankle injuries (p = 0.993 and 0.179, respectively), but both groups differed from the uninjured control groups (p < 0.001). There were no ceiling or floor effects. CONCLUSIONS: The OCLA-G was successfully developed as the first patient reported and injury specific outcome scale to measure the impact of OCLA induced symptoms on activities of daily living and sport. This study provides evidence for the reliability and validity of the OCLA-G assessing patients with OCLA. TRIAL REGISTRATION: The registration trial number is DRKS00009401 on DRKS. 'Retrospectively registered'. Date of registration: 10/12/2015.

Influence of Medial Patellofemoral Ligament Reconstruction on Patellofemoral Contact in Patients With Low-Flexion Patellar Instability: An MRI Study.

Background: Medial patellofemoral ligament (MPFL) reconstruction is a well-established procedure for the treatment of patients with patellofemoral instability (PFI) at low flexion angles (0°-30°). Little is known about the effect of MPFL surgery on patellofemoral cartilage contact area (CCA) during the first 30° of knee flexion. Purpose/Hypothesis: The purpose of this study was to investigate the effect of MPFL reconstruction on CCA using magnetic resonance imaging (MRI). We hypothesized that patients with PFI would have a lower CCA than patients with healthy knees and that CCA would increase after MPFL reconstruction over the course of low knee flexion. Study Design: Cohort study; Level of evidence, 2. Methods: In a prospective matched-paired cohort study, the CCA of 13 patients with low-flexion PFI was determined before and after MPFL reconstruction, and the data were compared with those of 13 healthy volunteers (controls). MRI was performed with the knee at 0°, 15°, and 30° of flexion in a custom-designed knee-positioning device. To suppress motion artifacts, motion correction was performed using a Moiré Phase Tracking system via a tracking marker attached to the patella. The CCA was calculated on the basis of semiautomatic cartilage and bone segmentation and registration. Results: The CCA (mean ± SD) at 0°, 15°, and 30° of flexion for the control participants was 1.38 ± 0.62, 1.91 ± 0.98, and 3.68 ± 0.92 cm2, respectively. In patients with PFI, the CCA at 0°, 15°, and 30° of flexion was 0.77 ± 0.49, 1.26 ± 0.60, and 2.89 ± 0.89 cm2 preoperatively and 1.65 ± 0.55, 1.97 ± 0.68, and 3.52 ± 0.57 cm2 postoperatively. Patients with PFI exhibited a significantly reduced preoperative CCA at all 3 flexion angles when compared with controls (P ≤ .045 for all). Postoperatively, there was a significant increase in CCA at 0° of flexion (P = .001), 15° of flexion (P = .019) and 30° of flexion (P = .026). There were no significant postoperative differences in CCA between patients with PFI and controls at any flexion angle. Conclusion: Patients with low-flexion patellar instability showed a significant reduction in patellofemoral CCA at 0°, 15°, and 30° of flexion. MPFL reconstruction increased the contact area significantly at all angles.

Change in Descriptive Kinematic Parameters of Patients with Patellofemoral Instability When Compared to Individuals with Healthy Knees-A 3D MRI In Vivo Analysis.

BACKGROUND: Patellofemoral instability (PFI) leads to chronic knee pain, reduced performance and chondromalacia patellae with consecutive osteoarthritis. Therefore, determining the exact patellofemoral contact mechanism, as well as the factors leading to PFI, is of great importance. The present study compares in vivo patellofemoral kinematic parameters and the contact mechanism of volunteers with healthy knees and patients with low flexion patellofemoral instability (PFI). The study was performed with a high-resolution dynamic MRI. MATERIAL/METHODS: In a prospective cohort study, the patellar shift, patella rotation and the patellofemoral cartilage contact areas (CCA) of 17 patients with low flexion PFI were analyzed and compared with 17 healthy volunteers, matched via the TEA distance and sex, in unloaded and loaded conditions. MRI scans were carried out for 0°, 15° and 30° knee flexion in a custom-designed knee loading device. To suppress motion artifacts, motion correction was performed using a moiré phase tracking system with a tracking marker attached to the patella. The patellofemoral kinematic parameters and the CCA was calculated on the basis of semi-automated cartilage and bone segmentation and registrations. RESULTS: Patients with low flexion PFI showed a significant reduction in patellofemoral CCA for 0° (unloaded: p = 0.002, loaded: p = 0.004), 15° (unloaded: p = 0.014, loaded: p = 0.001) and 30° (unloaded: p = 0.008; loaded: p = 0.001) flexion compared to healthy subjects. Additionally, patients with PFI revealed a significantly increased patellar shift when compared to volunteers with healthy knees at 0° (unloaded: p = 0.033; loaded: p = 0.031), 15° (unloaded: p = 0.025; loaded: p = 0.014) and 30° flexion (unloaded: p = 0.030; loaded: p = 0.034) There were no significant differences for patella rotation between patients with PFI and the volunteers, except when, under load at 0° flexion, PFI patients showed increased patellar rotation (p = 0.005. The influence of quadriceps activation on the patellofemoral CCA is reduced in patients with low flexion PFI. CONCLUSION: Patients with PFI showed different patellofemoral kinematics at low flexion angles in both unloaded and loaded conditions compared to volunteers with healthy knees. Increased patellar shifts and decreased patellofemoral CCAs were observed in low flexion angles. The influence of the quadriceps muscle is diminished in patients with low flexion PFI. Therefore, the goal of patellofemoral stabilizing therapy should be to restore a physiologic contact mechanism and improve patellofemoral congruity for low flexion angles.

Outcome Evaluation of Distal Femoral Fractures Following Surgical Management: A Retrospective Cohort Study.

BACKGROUND: Distal femur fractures are challenging in surgical management as the outcome is crucial for restoring the biomechanical stability and longitudinal axis of the leg and function of the knee joint. METHODS: A retrospective review of all distal femoral fractures treated in a level I trauma center over a decade was performed. The radiographs were reviewed for fracture entity, osseous healing, implant failure, mechanical axis, and degenerative joint changes. Clinical outcome was reviewed regarding postoperative complications and postoperative range of motion of the knee joint. RESULTS: 130 patients who were managed with screw fixation (n = 35), plating systems (n = 92) or intramedullary nailing systems (n = 3) remained for evaluation. Mean follow up was 26 months. Clinical outcome was significantly better for flexion degrees following screw fixation (p = 0.009). Delayed fracture union (p = 0.002) or non-union (p = 0.006) rates were significantly higher in plate osteosynthesis. Mild pathologic deformity for varus and valgus collapse was found following plate osteosynthesis. CONCLUSIONS: Screw fixation shows fewer postoperative complications than plate fixation and is favored for extra and partial intraarticular distal femur fractures. Plating constructs remain the superior fixation method in complex distal femur fractures but are associated with higher rates of non-union and leg axis deviation.

Does the Pathologic Fracture Predict Severe Paralysis in Patients with Metastatic Epidural Spinal Cord Compression (MESCC)?-A Retrospective, Single-Center Cohort Analysis.

Currently, there is uncertainty about the predictive factors for metastatic epidural spinal cord compression (MESCC) and consecutive symptomatology in tumor patients. Prognostic algorithms for identifying patients at risk for paralysis are missing. The influence of the pathologic fracture on the patient's symptoms is widely discussed in the literature and we hypothesize that pathologic fractures contribute to spinal cord compression and are therefore predictive of severe paralysis. We tested this hypothesis in 136 patients who underwent surgery for spinal metastases. The most common primary cancers were prostate (24.3%, n = 33), breast (11.0%, n = 15), lung (10.3%, n = 14), and cancer of unknown primary (10.3%, n = 14). MESCC primarily affected the thoracic (77.2%, n = 105), followed by the lumbar (13.2%, n = 18) and cervical (9.6%, n = 13) spine. Pathologic fractures occurred in 63.2% (n = 86) of patients, mainly in osteolytic metastases. On the American spinal injury association (ASIA) impairment scale (AIS), 63.2% (n = 86) of patients exhibited AIS grade D and 36.8% (n = 50) AIS grade C-A preoperatively. The presence of a pathologic fracture alone did not predict severe paralysis (AIS C-A, p = 0.583). However, the duration of sensorimotor impairments, patient age, spinal instability neoplastic score (SINS), and the epidural spinal cord compression (ESCC) grade together predicted severe paralysis (p = 0.006) as did the ESCC grade 3 alone (p = 0.028). This is in contrast to previous studies that stated no correlation between the degree of spinal cord compression and the severity of neurologic impairments. Furthermore, the high percentage of pathologic fractures found in this study is above previously reported incidences. The risk factors identified can help to predict the development of paralysis and assist in the improvement of follow-up algorithms and the timing of therapeutic interventions.

Management of juvenile and aneurysmal bone cysts: a systematic literature review with meta-analysis.

PURPOSE: Numerous approaches to the management of juvenile and aneurysmal bone cysts (ABC) are described in the specialist literature together with discussion of the associated healing and recurrence rates. Since there is currently no evidence-based treatment standard for these conditions, the aim of this systematic literature review with meta-analysis was to examine the different management approaches, evaluate the corresponding clinical outcomes and, as appropriate, to formulate a valid treatment recommendation. METHODS: A systematic search on OVID Medline® based on a pre-existing search strategy returned 1333 publications. Having defined inclusion and exclusion criteria and analysis of the relevant full texts, 167 publications were included in the descriptive analysis and 163 in the meta-analysis. For this purpose, different subgroups were created, based on the type of cyst and the therapeutic procedure. Those subgroups were then analysed in relation to their healing rates, the number of recurrences and complication rates. RESULTS: For aneurysmal bone cysts, both surgical removal and Doxycycline injection lead to excellent outcomes (98% healing) and low recurrence rates (6% and 11% resp.). Curettage (91% healing), including its combination with autologous cancellous bone graft (96% healing), showed very good healing rates but higher recurrence rates (22% and 15%, resp.), which were however improved by preoperative selective arterial embolization. A critical view must be taken of radiotherapy (90% healing) and the injection of alcohol (92% healing) because of their high complication rates (0.43/cyst and 0.42/cyst, resp.). In the management of juvenile bone cysts, surgical interventions like curettage and cancellous bone graft (87% healing) are far superior to non-surgical approaches (51% healing), furthermore, the application of autologous cancellous bone graft reduced the recurrence rate (3% recurrence) compared to curettage alone (20% recurrence). In subgroup analysis, treatment by ESIN was found to produce excellent outcomes (100% healing), though the patient collectives were small. CONCLUSION: Surgical procedures to treat aneurysmal bone cysts appear to be the method of choice whereby Doxycycline injection may be an alternative. A surgical approach should be preferred in the treatment of juvenile bone cysts.

Chronic Ankle Instability - Mechanical vs. Functional. / Sprunggelenk-Instabilität: Wie unterscheide ich mechanisch von funktionell?

Chronic ankle instability arises from three interacting contributing factors: mechanical ankle instability, functional ankle instability, and perceived ankle instability. To decide on the most appropriate individual recommendation for therapeutic options, it is necessary to assess which of the two main aetiologies - functional vs. mechanical - is dominant in causing the perceived impairment. It is essential to perform a thorough analysis and diagnosis, even though quantifying mechanical ankle instability is still a challenge in the clinical approach to this common pathology. When diagnosing mechanical instability, the most established procedure is physical examination, although this unfortunately does not allow the deficit to be quantified. Additional options include stress-ultrasound, 3D stress-MRI (3SAM), ankle arthrometry, marker-based 3D motion analysis, and diagnostic ankle arthroscopy. Of these the latter is considered the gold standard, even though it is an invasive procedure, it may not be performed for diagnostic reasons only, and it also does not allow the mechanical instability to be quantified. For diagnosing functional instability there are non-instrumented tests such as the Star Excursion Balance Test or Y-Balance Test, posturography/stabilometry, and gait and running analysis, possibly combined with EMG acquisition and isokinetic strength testing.To date, the standard of care is conservative management of ankle instability, and the therapy should include sensorimotor training, strength training of the periarticular muscles, balance training, and gait and running exercises on different surfaces. However, it is increasingly clear that a certain degree of mechanical instability cannot be compensated for by functional training. Thus, it is the goal of differential diagnostics to identify those patients and guide them to mechanical therapy, including ankle bracing, taping, and surgical ligament reconstruction.