Contrast-enhanced ultrasound reveals perfusion differences between benign lipoma and semi-malignant atypical lipomatous tumors: A prospective clinical study.

PURPOSE: Soft tissue tumors (STT) are difficult to diagnose accurately, and distinguishing between benign and malignant tumors is challenging. Lipoma is the most common STT, while atypical lipomatous tumors (ALT) can dedifferentiate into malignant lipomatous tumors like grade 1 liposarcoma and require more radical therapy. This study aims to investigate the potential of contrast-enhanced ultrasound (CEUS) to differentiate between lipoma and ALT based on tumor perfusion. MATERIALS AND METHODS: We prospectively examined 52 patients who were scheduled for biopsy for suspected lipoma or ALT. The CEUS examination was performed using SonoVue as a contrast agent to quantify tumor perfusion using VueBox V7.1 software. Peak enhancement (PE), rise time (RT), wash-in perfusion index (WiPI), and wash-out rate (WoR) were used to assess contrast enhancement inside the STT. RESULTS: Among 50 tumors examined, 30 were lipomas, and 20 were ALTs. We found significant differences in perfusion between lipomas and ALTs (PE: 49.22 ± 45.75 a.u. vs. 165.67 ± 174.80; RT: 23.86 ± 20.47s vs. 10.72 ± 5.34 s; WiPI: 33.06 ± 29.94 dB vs. 107.21 ± 112.43 dB; WoR: 2.44 ± 3.70 dB/s vs. 12.75 ± 15.80 dB/s; p<.001). ROC analysis of PE resulted in a diagnostic accuracy of 74% for the detection of an ALT, and 77% for the detection of a lipoma. CONCLUSION: CEUS may enhance the differential diagnosis of benign lipomas and ALTs, with ALTs showing higher levels of perfusion. If larger prospective studies confirm these findings, CEUS could enhance diagnostic accuracy, guide surgical planning, and potentially reduce unnecessary treatments for patients presenting with ambiguous lipomatous tumors like lipoma or ALT.

Fixed-bearing is superior to mobile-bearing in lateral unicompartmental knee replacement: a retrospective matched-pairs analysis.

PURPOSE: Due to low incidence of isolated lateral osteoarthritis (OA), there are limited data on whether a fixed-bearing (FB) or a mobile-bearing (MB) design is superior for lateral unicompartmental knee replacement (UKR). The aim of this matched-pairs analysis was to compare both designs in terms of implant survival and clinical outcome. METHODS: Patients who received MB-UKR (Group A) and FB-UKR (Group B) at a single centre were matched according to gender, age at time of surgery and body mass index (BMI). Survivorship analysis was performed with the endpoint set as "revision for any reason". Clinical outcome was assessed using the Oxford knee score (OKS), visual analogue scale for pain (VAS), patients' satisfaction, University of California Los Angeles activity scale (UCLA) and the Tegner activity score (TAS). RESULTS: A total of 60 matched pairs were included with a mean follow-up (FU) of 3.4 ± 1.3 (range 1.2-5.0) years in Group A and 2.7 ± 1.2 (range 1.0-5.0) years in Group B. Survivorship between both groups differed significantly (Group A: 78.7%; Group B: 98.3%, p = 0.003) with bearing dislocation being the most common reason for revision in Group A (46.2%). The relative and absolute risk reduction were 92.2% and 20%, respectively, with 5 being the number needed to treat. There were no differences in OKS (Group A: 41.6 ± 6.5; Group B: 40.4 ± 7.7), VAS (Group A: 2.9 ± 3.2; Group B: 1.6 ± 2.2), UCLA (Group A: 5.7 ± 1.3; Group B: 5.9 ± 1.8) and TAS (Group A: 3.0 ± 1.0; Group B: 3.1 ± 1.2) between both groups on follow-up. CONCLUSION: Despite modern prosthesis design and surgical technique, implant survival of lateral MB-UKR is lower than that of FB-UKR on the short- to mid-term due to bearing dislocation as the most common cause of failure. Since clinical results are equivalent in both groups, FB-UKR should be preferred in treatment of isolated lateral OA. LEVEL OF EVIDENCE: Retrospective case-control study, Level III.

Short- to mid-term results of minimally invasive lateral unicompartmental knee replacement: 133 cases in a non-designer series.

INTRODUCTION: The aim of the current study was to demonstrate short- to mid-term survivorship as well as clinical outcome of lateral unicompartmental knee replacement (UKR) with a fixed-bearing (FB) design from a non-designer center using the Oxford Fixed Lateral prosthesis. MATERIALS AND METHODS: This single-center retrospective cohort study reports the results of 133 consecutive lateral FB-UKR. Survivorship analysis was performed with different endpoints and clinical outcome was measured using the Oxford-Knee-Score (OKS), American-Knee-Society-Score (AKSS-O), range-of-motion (ROM) and visual-analog-scale for pain (VAS). RESULTS: There were two revision surgeries with conversion to total knee replacements (TKR) due to persistent pain resulting in a survival rate of 98.5% (95% CI 93.5-99.6) with a mean follow-up (FU) of 3.3 ± 1.8 years (range 1-8.5). All outcome scores, VAS and ROM showed a significant improvement at final FU (p < 0.001). The OKS improved from 26 ± 7.8 (range 11-45) preoperatively to 39 ± 8.3 (range 13-48), the AKSS-O from 49.2 ± 14.6 (range 18-90) to 81.8 ± 15.1 (range 40-100), the AKSS-F from 53 ± 23.7 (range 0-100) to 80.4 ± 21.4 (range 5-100) and the ROM from 118 ± 17 (range 90-160) to 134 ± 9.5 (range 100-155). CONCLUSIONS: The short- to mid-term results following lateral FB-UKR demonstrate a high survivorship and good clinical outcome from an independent series. We, therefore, suggest that FB-UKR is a safe treatment option for isolated lateral OA if sufficient surgical experience is provided. LEVEL OF EVIDENCE: Retrospective cohort study, level IV.

Mobile bearing versus fixed bearing medial unicompartmental knee replacement: an independent two center matched-pairs analysis.

INTRODUCTION: The aim of the present study was to compare clinical outcome between patients following fixed-bearing (FB) or mobile-bearing (MB) unicompartmental knee replacement (UKR) for antero-medial knee osteoarthrosis (OA) at two independent orthopedic centers. MATERIALS AND METHODS: Matched-pairs were built between 35 patients receiving FB-UKR and 52 patients following MB-UKR regarding age at time of surgery, body mass index (BMI) and range of motion (ROM) preoperatively. Clinical and functional outcome was measured postoperatively by the American Knee Society Score (AKSS-O/AKSS-F), ROM, Tegner Activity Scale (TAS) as well as the Short Form 36 Health Survey (SF-36). RESULTS: The average treatment effect of the treated (ATT) after propensity score matching showed a significantly superior ROM in patients following MB-UKR (FB: 118°, MB: 124°). All remaining parameters had no statistically significant differences between both groups involving TAS, AKSS and SF-36. CONCLUSIONS: The present study suggests that MB-UKR can provide a greater ROM compared to FB-UKR on comparable patients. The authors believe that both designs are suitable for adequate improvement of clinical outcome and ROM for patients suffering from antero-medial osteoarthrosis of the knee joint. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

From Benign Lipoma to G3 Liposarcoma: Contrast-Enhanced Ultrasound Reveals Tumor Microperfusion and Indicates Malignancy.

OBJECTIVE: Lipomatous soft tissue tumors (STT), ranging from benign lipomas to malignant liposarcomas, require accurate differentiation for timely treatment. Complementary to MRI, Contrast-enhanced ultrasound (CEUS) is emerging as a promising tool, providing insight into tumor microperfusion in real-time. This study aims to explore the potential of preoperative CEUS in differentiating benign lipomatous tumors from malignant liposarcoma subtypes. METHODS: Eighty-seven patients with lipomatous STT scheduled for surgery were enrolled. Clinical and MRI assessments were conducted to obtain general tumor characteristics. CEUS was used for a standardized tumor perfusion evaluation. Perfusion analysis included peak enhancement, rise time, wash-in perfusion index, and wash-out rate, reflecting the perfusion kinetics. Histopathological results were obtained for every STT and compared to perfusion characteristics. RESULTS: In total, 48 lipoma, 23 ALT and 11 liposarcoma were identified. Significant differences in tumor microperfusion were demonstrated, with higher perfusion levels indicating higher malignancy (Peak enhancement [a.u.] of Lipoma: 145 ± 238; ALT: 268 ± 368; Liposarcoma: 3256 ± 4333; p (ALT vs. Liposarcoma) < 0.001). A perfusion-based identification of a benign lipoma or ALT versus sarcoma resulted in a positive predictive value of 93%. Patient-related factors (age, gender, BMI, ASA score, smoking status) had no significant impact on the CEUS-based perfusion parameters. CONCLUSION: Our study suggests CEUS as a capable non-invasive tool for improving preoperative assessment of lipomatous STT. It can assist in the distinction between benign and malignant STT, accelerating treatment decisions and enhancing patient outcomes. Significant correlations between CEUS-derived parameters and malignancy highlight its risk assessment potential.

Clinical and Functional Results of Cementless Unicompartmental Knee Arthroplasty with a Minimum Follow Up of 5 Years-A Consecutive Cohort of 201 Patients.

The number of unicompartmental knee replacements (UKR) is increasing. Alongside various advantages, the revision rate of cemented UKR is higher compared to total knee arthroplasty (TKR). In contrast, cementless fixation shows reduced revision rates, compared to the cemented UKR. However, most of the recent literature is based on designer-dependent studies. In this retrospective, single-center cohort study, we investigated patients who underwent cementless Oxford UKR (OUKR) between 2012 and 2016 in our hospital with a minimum follow-up of five years. Clinical outcome was evaluated using the OKS, AKSS-O, AKSS-F, FFbH-OA, UCLA, SF-36, EQ-5D-3L, FJS, ROM, pain, and satisfaction measures. Survival analysis was performed with reoperation and revision as endpoints. We included 201 patients (216 knees) for clinical evaluation. All outcome parameters increased significantly from pre- to postoperative stages. The five-year survival rate was 96.1% for revision surgery and 94.9% for reoperation. The main reasons for revision were the progression of osteoarthritis, inlay dislocation, and tibial overstuffing. Two iatrogenic tibial fractures appeared. Cementless OUKR shows excellent clinical outcome and high survival rates after five years. The tibial plateau fracture in cementless UKR represents a serious complication and requires modification of the surgical technique.

Contrast-Enhanced Ultrasound-Assessed Supraspinatus Muscle Perfusion Indicates Better Tissue Vitality and Outcome After Supraspinatus Tendon Repair and Subacromial Decompression.

OBJECTIVE: Supraspinatus tendon (SSP) tears are a frequent indication for shoulder surgery. Therapy options include physiotherapy, tendon repair and less invasive surgical options like subacromial decompression (SAD). The selection of the most appropriate treatment depends on the specific characteristics and needs of each patient subgroup. Typically, physically active patients are candidates for tendon repair, while a conservative approach is preferred for individuals with severe muscle degeneration or low physical demands. The goal of this study was to assess the impact of contrast-enhanced ultrasound (CEUS)-assessed SSP muscle perfusion on post-operative shoulder function and tendon healing in patients undergoing SSP repair or SAD, thereby enhancing personalized therapy for SSP tendon tears. METHODS: Two cohorts of patients with SSP tendon tears were treated either by SAD or tendon repair. Pre-operative and 6-month post-operative SSP muscle perfusion was quantified using CEUS and investigated as a surrogate for tissue vitality. The magnetic resonance imaging-derived parameters fatty infiltration and tendon retraction and established shoulder function scores were assessed pre- and post-operatively. RESULTS: Thirty-five SSP repair patients were compared with 20 SAD patients. Pre-operative perfusion was comparable in the SAD and SSP repair cohorts when a re-tear occurred (wash-in perfusion index = 103.8 ± 124.0 vs. 114.6 ± 155.0, p = 0.83), while being significantly higher among patients with an intact repair (103.8 ± 124 vs. 325.4 ± 388.6, p = 0.006). Below-median pre-operative muscle perfusion was associated with lower post-operative shoulder function (Constant score: 59 ± 28 vs. 78 ± 19, p = 0.012). CONCLUSION: CEUS can visualize SSP muscle perfusion as a surrogate for tissue vitality and tendon healing, which is associated with better post-operative shoulder function.

Physical Activity of Young Patients following Minimally Invasive Lateral Unicompartmental Knee Replacement.

Unicompartmental knee replacement (UKR) has increased in popularity in recent years, especially in young patients with high demands on their athletic ability. To date, there are no data available on the physical activity of young patients following lateral UKR. The aim of this study was to demonstrate return-to-activity rate and sporting activity of patients aged 60 years or younger following lateral UKR with a fixed-bearing (FB) prosthesis. Thirty-seven patients aged 60 years or younger after lateral FB-UKR were included. Sporting activities were assessed using the University of California Los Angeles activity scale (UCLA) and the Tegner activity score (TAS). Clinical outcome was measured using the Oxford Knee Score (OKS), range of motion (ROM) and visual analogue scale (VAS). The mean follow-up (FU) was 3.1 ± 1.5 years and the mean age at surgery was 52.8 ± 3.1 years. The return-to-activity rate was 87.5% and 49% of patients were highly active postoperatively as defined by an UCLA score of 7 or higher. All clinical parameters increased significantly postoperatively. We demonstrated a high return-to-activity rate with nearly half of the patients achieving high activity levels. Longer FU periods are necessary to evaluate the effect of activity on implant survival.

Minimally invasive lateral unicompartmental knee replacement: Early results from an independent center using the Oxford fixed lateral prosthesis.

PURPOSE: The aim of the present study was to assess clinical outcome as well as short-term survivorship of fixed-bearing lateral unicompartmental knee replacement (UKR) from a non-designer centre using the Oxford Fixed Lateral prosthesis. METHODS: This single-centre retrospective cohort study reports the short-term results of 51 consecutive patients (52 knees) after fixed-bearing lateral UKR with a minimum follow-up of one year. Survivorship analysis was performed with different endpoints and clinical outcome was measured using the Oxford Knee Score (OKS), objective American Knee Society Score (AKSS-O), range-of-motion (ROM), visual analog scale for pain (VAS), Tegner activity score and UCLA score. RESULTS: There was no revision surgery, defined as exchange of at least one of the components resulting in a survival rate of 100% at two years. Three patients required further surgical treatment resulting in a survival rate of 94.2% (95% confidence interval (CI): 83.2-98.1%) with the endpoint 'any reoperation'. Outcome scores, VAS and ROM showed a statistically significant improvement at final follow-up (P < .001). The OKS improved from 26.4 ±â€¯6.9 (12-41) preoperatively to 39.7 ±â€¯8.4 (15-48), the AKSS-O from 54.3 ±â€¯15.3 (18-90) to 82.2 ±â€¯15.6 (40-100), the American Knee Society Functional Score from 56.4 ±â€¯21.3 (10-100) to 83.1 ±â€¯20.2 (five to 100) and the ROM from 123.5 ±â€¯13.5 (90-140) to 134 ±â€¯10.3 (95-150). CONCLUSION: Early results of fixed-bearing lateral UKR using the Oxford-Fixed-Lateral prosthesis were encouraging with a significant improvement in pain and knee function as well as an excellent survivorship of 100% at a mean follow-up of two years. Further follow-up is necessary to evaluate the long-term effectiveness of this device and the surgical technique. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Mechanical stretch-induced vascular hypertrophy occurs through modulation of leptin synthesis-mediated ROS formation and GATA-4 nuclear translocation.

BACKGROUND: Obesity and hypertension are associated with increased leptin production contributing to cardiovascular remodeling. Mechanisms involving mechanical stretch-induced leptin production and the cross talk between signaling pathways leading to vascular remodeling have not been fully elucidated. METHODS AND RESULTS: Rat portal vein (RPV) organ culture was used to investigate the effect of mechanical stretch on leptin protein expression in vascular smooth muscle cells (VSMCs). Moreover, the involvement of reactive oxygen species (ROS), the RhoA/ROCK pathway, actin cytoskeleton dynamics and the transcriptional factor GATA-4 activation in mechanical stretch-induced vascular remodeling were investigated. Stretching the RPV for 1 or 24 h significantly increased leptin protein level and ROS formation in VSMCs, which was prevented by 1 h pretreatment with the ROCK inhibitor Y-27632 and the actin cytoskeleton depolymerization agent cytochalasin D. Moreover, Western blotting and immunohistochemistry revealed that mechanical stretch or treatment with 3.1 nmol/L leptin for 24 h significantly increased actin polymerization, as reflected by an increase in the F-actin to G-actin ratio. Increases in blood vessels' wet weight and [(3)H]-leucine incorporation following a 24 h treatment with conditioned media from cultured stretched RPVs indicated RPV hypertrophy. This effect was prevented by 1 h pretreatment with anti-leptin antibody, indicating leptin's crucial role in promoting VSMC hypertrophy. As an index of GATA-4 activation, GATA-4 nuclear translocation was assessed by immunohistochemistry method. Pretreating VSMC with leptin for 1 h significantly activated GATA-4 nuclear translocation, which was potently attenuated by the NADPH oxidase inhibitor apocynin, Y-27632, and cytochalasin D. CONCLUSION: Our results demonstrate that ROS formation, RhoA/ROCK pathway, and GATA-4 activation play a pivotal role in mechanical stretch-induced leptin synthesis leading to VSMC remodeling.