Impingement Test Research Articles

Functional and Radiological Outcomes of the Surgical Treatment of Acute Acromioclavicular Dislocation with Anchors Associated with Clavicle and Scapula Fixation.

Objective To evaluate the clinical, radiological and functional results of the surgical treatment of acute acromioclavicular dislocation using a coracoclavicular fixation technique (syndesmopexy) with two metallic anchors, temporary clavicle and scapula fixation, and transfer of the coracoacromial ligament. Methods Longitudinal observational study of 30 patients with diagnoses of acute acromioclavicular dislocation, who were submitted to surgical treatment with a minimum follow-up of six months, and who were evaluated clinically, radiologically, and by the University of California at Los Angeles (UCLA), the Disabilities of the Arm, Shoulder and Hand (DASH) and the Constant-Murley functional scores. Results The mean values of the scores were: UCLA = 32; DASH = 11.21; and Constant-Murley = 86.93, with satisfactory results higher than 80%. The unsatisfactory results were associated with acromioclavicular pain on palpation, positive subacromial impingement tests, and older age group, presenting statistical significance ( p < 0.05). Radiologically, higher values on account of the coracoclavicular distance ratio from the operated shoulder compared to the normal shoulder were related to worse outcomes, but with no statistically significant difference. No associations were found between the results of the functional scores and the variables degree of the injury, coracoacromial ligament transfer, clinical impression of loss of reduction and scapulothoracic dyskinesis. Conclusion The technique used provides an efficient fixation, with a high level of satisfaction according to the UCLA, Constant-Murley and DASH scores; moreover, it has a low complication rate, despite the high rate of residual radiological acromioclavicular subluxation.

Femoroacetabular Impingement Patients With Decreased Femoral Version Have Different Impingement Locations and Intra- and Extraarticular Anterior Subspine FAI on 3D-CT–Based Impingement Simulation: Implications for Hip Arthroscopy

Background: It remains unclear whether decreased femoral version (FV) causes anterior intra- or extra-articular femoroacetabular impingement (FAI). Therefore, we evaluated symptomatic hips with decreased FV, with and without cam and pincer FAI, by using computed tomography (CT)–based virtual 3-dimensional (3D) impingement simulation and compared this group with patients with normal FV and with asymptomatic hips. Purpose: To investigate (1) the osseous range of motion, (2) the osseous femoral and acetabular impingement zones, and (3) whether hip impingement is extra- or intra-articular in symptomatic hips with FAI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved, retrospective comparative analysis was performed on a total of 84 hips in 68 participants. Of these, 37 hips in 24 symptomatic patients with FAI had decreased FV. These hips were compared with 21 hips of 18 symptomatic patients with anterior FAI with normal FV (10°-25°) and 26 asymptomatic hips with no FAI and normal FV. All patients with FAI were symptomatic and had anterior hip pain and a positive anterior impingement test. They underwent pelvic CT scans to measure FV. Decreased FV was defined as FV less than 5°. The 37 hips with decreased FV presented both with and without cam and pincer FAI. All 84 hips were evaluated by use of CT-based 3D models and a validated 3D range of motion and impingement simulation. Asymptomatic hips were contralateral normal hips imaged in patients undergoing total hip arthroplasty. Results: Hips with FAI combined with decreased FV had a significantly (P < .001) lower mean flexion (114°± 8° vs 125°± 13°) and internal rotation (IR) at 90° of flexion (18°± 6° vs 32°± 9°, P < .001) compared with the asymptomatic control group. Symptomatic patients with FAI and normal FV had flexion of 120°± 16° and IR at 90° of flexion of 23°± 15°. In a subgroup analysis, we found a significantly (P < .001) lower IR in 90° of flexion in hips with FV less than 5° combined with mixed-type FAI compared with hips with FV less than 5° without a cam- or pincer-type deformity. The maximal acetabular impingement zone for hips with decreased FV was located at the 2-o’clock position and ranged from 1 to 3 o’clock. In hips with decreased FV, most of the impingement locations were intra-articular but 32% of hips had combined intra- and extra-articular FAI in internal rotation in 90° of flexion. During the flexion-adduction-IR test performed in 10° and 20° of adduction, extra-articular subspine FAI had significantly (P < .001) higher prevalence (68% and 84%) in hips with decreased FV compared with normal hips. Conclusion: Hips with FAI and decreased FV had less flexion and internal rotation in 90° of flexion compared with the asymptomatic control group. The majority of hip impingement due to low FV was intra-articular, but one-third of samples had combined intra- and extra-articular subspine FAI. Anterior extra- and intra-articular hip impingement can be present in patients who have FAI with decreased FV. This could be important for patients undergoing hip arthroscopy.

The effect of using different coordinate systems on in-vivo hip angles can be estimated from computed tomography images

Measurements of hip kinematics inherently depend on the coordinate system in which they are derived, yet the effect of the coordinate system definition on calculations of hip angles is not well-understood. Herein, hip angles calculated during dynamic activities were compared using coordinate systems described in the literature. In-vivo kinematic data of 24 participants (13 males) were analyzed during gait and the anterior impingement test using dual fluoroscopy and model-based tracking. Two coordinate systems for the pelvis (anterior pelvic plane, International Society of Biomechanics [ISB]) and three coordinate systems for the femur (table top plane with two definitions of the superior-inferior axis, ISB) were evaluated. Bony landmarks visible on computed tomography (CT) images were identified to establish each coordinate system and used as the basis to calculate differences in hip angles between coordinate system pairs. In the analysis during gait, the maximum differences derived from various coordinate system definitions were 6.7° ± 5.5° for flexion, 7.7° ± 2.1° for rotation, and 5.5° ± 0.7° for adduction. For the anterior impingement test, the differences were 8.1° ± 5.9°, 7.1° ± 1.2°, and 5.3° ± 0.7°, respectively. Landmark-based analysis using CT images could estimate these dynamic differences with errors less than 1.0°. Our results indicate that hip angles can be accurately transformed to angles calculated in different coordinate systems by accounting for the inherent bony anatomy. This information may aid in the interpretation of results across biomechanical studies of the hip.

Multidimensional durability of superhydrophobic self-cleaning surface derived from rice-husk ash

Surface with inherent self-cleaning characteristics is often deemed and desired. However, lack of durability and high cost limits the applicability of such surfaces in a real-life scenario. In present work, we report the development of durable and cost-effective nanocomposite coatings using silica particles (˜ 250 nm) derived from agricultural waste, rice-husk and different fractions of polydimethylsiloxane (PDMS). Developed coatings showed the presence of hierarchical structures with nanoscale protrusions. The surface morphology of the coatings was significantly influenced by the PDMS content with roughness factor following an inverse correlation. Static and dynamic contact angles increased with decreasing PDMS content with maximum values observed to be in excess of 160°. Simultaneously, the contact angle hysteresis (< 5° to 20°) and tilting angle (5° to 60°) were also significantly influenced by the PDMS fraction. The observed results are related with ability to retain stable Cassie state and pinning of the liquid-air interface by nano protrusions. Droplet impingement tests and critical wetting angle calculations showed transition from Cassie to metastable wetting state for coatings with higher PDMS. Durability studies performed under different modes indicated a trade-off with self-cleaning ability, highlighting an optimum composition possessing required characteristics. The selected coating subjected to weathering test showed due resilience under outdoor conditions. The present work showed that the agricultural waste can be effectively used for developing low-cost high-end product possessing exceptional functionalities.

Improvement of erosion resistance of alumina-phosphate ceramic coating on mild steel by SiC addition

This research is focused on the application of the Al2O3-phosphate ceramic coating on mild steel surface to protect mild steel from erosion in coal dust environment. Erosion resistance of mild steel could be improved by overlay it with SiC in the Al2O3-phosphate ceramic coating. As a filler, Al2O3 was mixed with 20%, 40%, and 60% SiC by using aluminium phosphate as a binder and heated at 220 °C for 5 hours. X-ray diffraction testing was conducted to observe the phase of Al2O3-SiC phosphate ceramic coating. Meanwhile, surface morphology and adhesion characteristic of Al2O3-SiC phosphate ceramic coating were analyzed by scanning electron microscope. To analyze the erosion resistance quantitatively solid particle impingement test by applying gas jets at the right angle (90°) against a sample surface has been conducted. The results showed that Al2O3-SiC phosphate ceramic coating is strongly bound to the mild steel surface without the presence of any void. The higher the SiC content can increase the ceramic coating density and its erosion resistance. The SiC 60% produces four times higher erosion resistance than uncoated mild steel. The material characterization of Al2O3-SiC phosphate ceramic coating proves that SiC gives a significant impact on the enhancement of erosion resistance of the Al2O3-SiC phosphate ceramic coating.

Characteristic and Erosion Study of Uncoated Sand Proppant Using Impingement Test

The characterization and properties of sand from beaches in Malaysia that has potential to be used as proppant in hydraulic fracturing was investigated through impingement tests. Eight sand samples were obtained from eight different locations in Malaysia; three samples from West Coastal beaches (Selangor) and five from East Coastal beaches (Kelantan). These impingement tests were conducted by varying several parameters i.e. size ranges of sand, type of targeted metal and distance of nozzle standoff from target. In these tests, air was fed through an acrylic pipe with inner diameter of 8 mm and 4 m length at gas velocity of 100 m/s and flow rate of 200 l/min. 250 g of sand samples were fed in compressed air stream and the samples were projected toward targeted metal i.e. mild steel and aluminium with a 90° of impingement angle. These tests were conducted at different separation distance of 0.5, 2.5 and 5.0 inches of nozzle and target. The results were analysed by measuring the mass loss of the metals after impingement and the images of the impinged metals were captured using camera. The highest metal loss was obtained when the targeted metal was impacted with the largest size range of sand samples. The mass loss of mild steel ranged from 0.03 to 0.16 g and 0.10 to 0.22 g for aluminium, at a variable distance between the nozzle and metal target due to higher hardness of mild steel than aluminium. The mass loss reduced when the distance between nozzle and metal target increased due to energy loss because of the inter particle collision.

Could long-term overhead load in painters be associated with rotator cuff lesions? A pilot study.

BackgroundUse of the arm above shoulder level has been described as a risk factor for developing rotator cuff tears (RCT). There is a lack of information regarding the frequency and distribution of RCT in a population using their arms above shoulder level during daily work. The aim of this study was to analyze clinical and radiographic findings in a population of painters working more than 10 years and to compare the results with a control group (CG)Materials and methods100 individuals working more than 10 years as a painter were compared to 100 matched controls without using their arms above shoulder level. MRI scans were performed in all participants. Clinically, the Constant score, DASH score and range of motion (ROM) of the shoulders were analyzed.ResultsIn the painter group (PG) a tear of the supraspinatus tendon was detected in 45% (10%full-thickness; 35% partial) compared to 8% in the (CG) (3% full-thickness; 5%partial; p<0.001). Impingement test was painful in 52% of PG and 7% of CG (p<0.001). The Constant score in the PG was significantly lower compared to the CG (62 vs. 93 points; p<0.001). PG had significantly worse DASH scores and inferior active and passive ROM of the dominant shoulders. In the multivariable logistic regression analysis, three risk factors (smoking, sports activity, and handedness) showed no effect. However, group membership (PG/CG) and age revealed a significant effect.ConclusionLong-term occupational load on the shoulders in painters seems to be associated with an increased risk for developing RCT. Our findings may provide support for developing preventive strategies for this unique cohort.Level of evidence: III

Effects of the precipitation of secondary phases on the erosion-corrosion of 25% Cr duplex stainless steel

This study examined the effect of aging at 850 °C on the precipitation of secondary phases and the resultant erosion-corrosion behavior of 25% Cr duplex stainless steels (DSS). An aging time of 30 min, which led to a ratio of reactivation current to activation current (ir/ia × 100) of ˜1% in a DL-EPR test and a current density of ˜0.8 mA cm−2 at 9 m s−1 in a jet impingement test, is regarded as a boundary aging condition for erosion-corrosion. Further, the current density response of ˜0.8 mA cm−2 can be considered a criterion for the surface depassivation resulting from erosion-corrosion.

FEMOROACETABULAR IMPINGEMENT INSURANCE COVERAGE TRENDS IN RECENT YEARS: A COHORT BASED ANALYSIS

Background: The diagnostic criteria for surgical indication of femoroacetabular impingement (FAI) remain controversial. With a growing body of literature investigating the quality of these criteria, little is known about the direction that these have had on changes of third-party policies. The purpose of this study was to measure how these changes in policy would affect the exclusion of a cohort of previously identified FAI patients who were treated operatively. Methods: Four insurance companies’ coverage policies with specific criteria for the surgical treatment of FAI were applied to this population at two time points, 2012 and 2018, to determine whether these third-party payer criteria for FAI surgery were met. The insurance criteria were assessed in a prospective multicenter cohort of 712 patients undergoing primary FAI surgery. The policies listed various combinations of age, symptom duration, positive impingement test, radiographic osteoarthritis, radiographic sign of CAM and/or pincer impingement, and physical exam findings. Results: The cohort of 712 hips included 324 men [45.5%] and 388 females [54.5] with a mean age of 28.7 years. Overall, insurance criteria were not met in: Insurance #1 old 30.1%, new 25.7%; Insurance #2 old and new 17.8%, Insurance #3 old 21.9%, new 21.1%; and Insurance #4 old 17.8%, new 14.9%-20.6%. In 2012, the average percent exclusion of the four companies was 21.9%, this number decreased slightly to 20.6% overall in 2018. The most likely reason to be excluded was found to be failure to meet imaging criteria. The second most likely failed characteristic was a negative impingement test (65 patients excluded). Several insurance companies continue to utilize Outerbridge criteria for cartilage lesions which cannot be assessed preoperatively. Discussion and Conclusion: The diagnosis of FAI and its surgical indications have no definitive set criteria. Our study shows that with a six-year span of growing literature and updated policies, nearly 1 in 5 patients deemed to need surgical intervention by experienced hip preservation surgeons would still be denied coverage. There is a need for continued improvement of consensus regarding the diagnosis of FAI and appropriate indications for surgical intervention based on the available literature.

ISCHIOFEMORAL IMPINGEMENT IN ADOLESCENTS: FROM CLINICAL PRESENTATION TO RETURN TO SPORTS

Background: Ischiofemoral impingement is an often unrecognized cause of hip pain in adolescents. It is caused by abnormal contact between the proximal femur and the ischium. The aim of our work is to describe clinical presentation, imaging findings and functional outcomes of ischiofemoral impingement in adolescents. Methods: We performed a retrospective study. Clinical files were reviewed (age, sex, type and duration of symptoms and hip physical examination). Imaging findings were evaluated in pelvis radiographs (presence of coxa profunda, acetabular protrusio, Wiberg angle, femoral neck shaft angle and acetabular retroversion) and in MRI (quadratus femoris edema, measurement of ischiofemoral and quadratus femoris space). Lower extremity functional scale (LEFS) were used to measured response to a physiotherapy protocol. Also relapse and time to sports return were recorded. Results: 24 hips, two bilateral in 20 female patients and 2 male patients, with 13 years-old on average (9-18) were obtained. Main symptom was hip pain with latency to consultant of 9 days on average (2-14). All patients practiced school sports, the most frequent was gymnastics. Positive FADIR test, ischiofemoral impingement test and pain on palpation of the ischium and gluteus medius were found in everyone. The median of Wiberg angle was 37º (25-48), femoral shaft angle 138º (128-144), and coxa profunda was present in 5 hips. MRI showed 13 hips with quadratus femoris edema, one with muscle atrophy, ischiofemoral space was 20 mm on average (16-25) and quadratus femoris space 17 mm on average (13-21). Our physiotherapy protocol was followed for all patients with a median of 18 sessions (10-30). LEFS improved from 56.4% (30-93) to 92% (80-100) (p=0,02). Time to turn asymptomatic was 6 months on average (3-13). With 2 years follow up, 2 hips had recurrence of symptoms. Time to sports return was 5 months on average (3-7). Conclusions: Ischiofemoral impingement is cause of hip pain in active female adolescents. X-rays are inespecific and MRI shows typically quadratus femoris edema. Conservative treatment with physiotherapy is an effective method that allows sports return in few months. This is the first report in the literature regards ischiofemoral impingement in pediatric population including results of treatment and return to sports.

Superhydrophobic surface on aeronautical materials via the deposition of nanoparticles and a PDMS seal

This paper reports a stable superhydrophobic surface on resin composites through the coprecipitation process of hydroxyethyl cellulose and modified Zn-particles, subsequently with the use of PDMS seal. Surface morphologies and chemical compositions are investigated with SEM, EDS, and FT-IR. As expected, the prepared surface has the water repellency with the contact angle of 153° and the sliding angle of 1°, respectively. According to the comparison of different specimens when after the liquid impingement test, it can be reasonably demonstrated that appropriate PDMS seal improves the stability with regard to superhydrophobic surfaces. When superhydrophobic surface is soaked chronically and impinged strongly by water, its water repellency is going to reduce. However, further surface modification introduced by combustion leads to excellent water repellency again. And the sliding angle value of further modified surface is below 1°. The preparation of superhydrophobic surface is also applicable to a paper. This superhydrophobic paper is less flammable than the untreated paper. In addition, the as-prepared superhydrophobic surface exhibits good self-cleaning ability towards avoiding different types of contaminants.

Diagnosis and treatment of labral tear.

Objective:To review the literature regarding diagnosis and treatment of labral tear.Data sources:A systematic search was performed in PubMed using various search terms and their combinations including hip, labrum, acetabular labral tear, arthroscopy, diagnosis, and anatomy.Study selection:For each included study, information regarding anatomy, function, etiology, diagnosis, and management of acetabular labral tear was extracted.Results:Five hundred and sixty abstracts about anatomy, function, etiology, diagnosis, and management of acetabular labral tear were reviewed and 66 selected for full-text review. The mechanism of labral tear has been well explained while the long-term outcomes of various treatment remains unknown.Conclusions:Labral tear is generally secondary to femoroacetabular impingement, trauma, dysplasia, capsular laxity, and degeneration. Patients with labral tear complain about anterior hip or groin pain most commonly with a most consistent physical examination called positive anterior hip impingement test. Magnetic resonance arthrography is a reliable radiographic examination with arthroscopy being the gold standard. Conservative treatment consists of rest, non-steroidal anti-inflammatory medication, pain medications, modification of activities, physical therapy, and intra-articular injection. When fail to respond to conservative treatment, surgical treatment including labral debridement, labral repair, and labral reconstruction is often indicated.

Femoroacetabular impingement after the femoral neck fracture healed in a nonanatomical position

Introduction. Femoroacetabular impingement is the result of the pathological conditions in the osseous acetabulum and/or the proximal femur. One of its causes is a non-anatomically healed femoral neck fracture. Case report. A male, aged 51, with a subcapital left femoral neck fracture was treated conservatively. The fracture healed 9 months later and although the patient was walking on crutches he suffered from pain in the left groin. The X-ray images showed the valgus and the retroposition of the left femoral head. The patient was operated on and intraoperatively the thickness and a bone prominence in the anterosuperior femoral neck area in the line of the previous fracture were found, which was pressing and spreading beneath the acetabular labrum, thus squeezing the acetabular cartilage. The labrum lesion which was found was the result of the mechanical pressure of the existing femoral neck deformity during the hip movements. Irretrievably damaged part of the labrum was resected and the anterosuperior femoral headneck osteochondroplasty was done. One year after the surgery, the patient had no pain, he walked without limping, the impingement test was negative, the radiological parameters were adjusted and there were no signs of the avascular necrosis of the femoral head. Conclusion. The femoral neck fracture should be treated adequately with the full anatomical position and the proper internal fixation. If the deformity occurs as the result of a treatment, it should be removed as soon as possible to prevent the osteoarthritis of the hip.

Accuracy of Magnetic Resonance Imaging and Computed Tomography Arthrography in Diagnosing Acetabular Labral Tears and Chondral Lesions.

BackgroundWe investigated sensitivity, specificity, and accuracy of magnetic resonance imaging (MRI) and computed tomography arthrography (CTA), on the basis of arthroscopic findings, to diagnose acetabular labral tears and chondral lesions.MethodsWe retrospectively reviewed the results of MRI and subsequent CTA in 36 hips that underwent arthroscopic surgery (33 patients; 17 males [17 hips] and 16 females [19 hips]; average age, 35 years). All patients had positive impingement test results and groin pain. We analyzed sensitivity, specificity, and accuracy of MRI and CTA by comparing with the arthroscopic findings. Interobserver agreement and intraobserver reproducibility of the presence of tears and cartilage lesions on MRI and CTA were calculated using Kappa coefficients.ResultsThe sensitivity, specificity, and accuracy of MRI for detection of acetabular labral tears by two observers were 60%, 80%, and 64%, respectively, and 65%, 70%, and 69%, respectively. The sensitivity, specificity, and accuracy of CTA for detection of labral tears by both observers were 85%, 90%, and 86%, respectively, and 92%, 80%, and 89%, respectively. However, the sensitivity and specificity of MRI for detection of acetabular chondral lesions by both observers were 36% and 84%, respectively, and 46% and 88%, respectively. The sensitivity and specificity of CTA for detecting acetabular cartilage lesions by both observers were 46% and 72%, respectively, and 64% and 72%, respectively. Intraobserver reproducibility for detection of labral tears and chondral lesions by using MRI was substantial (κ = 0.756 and κ = 0.693, respectively). Interobserver reliability for detection of labral tears and chondral lesions by using MRI was substantial (κ = 0.700 and κ = 0.875, respectively). Intraobserver reproducibility for detection of labral tears and chondral lesions by using CTA was substantial (κ = 0.832 and κ = 0.774, respectively). Interobserver reliability for detection of labral tears and chondral lesions by using CTA was high (κ = 0.886 and κ = 0.596, respectively).ConclusionsThis study demonstrated that the accuracy of MRI to detect an acetabular labral tear and a chondral lesion of the hip joint was not sufficient. CTA was reliable in the diagnosis of acetabular labral tears. However, both CTA and MRI were also of limited value to detect chondral lesions.

Air flow and chip removal in minimum quantity lubrication drilling

Abstract Chip removal is a significant problem in high throughput minimum quantity lubrication (MQL) drilling, due to increased feed rates and the lack water-based coolant to flush chips. Chip removal difficulties in MQL drilling may drive the use of increased air pressures at a significant cost and energy penalty. This paper summarizes basic studies of air flow and chip removal for MQL drilling, intended to provide a physical basis for process and tooling design with minimal use of high air pressures. Air flow measurements on drill blanks show that the air flow rate depends primarily on the drill coolant hole diameter and input air pressure. Air speed measurements, made using a novel plate impingement test, show that the average air speed increases with increasing coolant hole diameter, but not with increasing pressure. An energy-based analysis of chip removal shows the effects of drill and process design parameters on chip removal. Trends predicted by this analysis are verified through vertical drilling experiments to measure chip removal efficiency. It is shown that the coolant hole diameter has a large influence on air speed and chip removal efficiency, so that drills with the largest practical coolant hole diameter should be tested before increased air pressure is adopted. It is also shown that increasing the spindle speed improves chip evacuation for helical drills. Recommendations for drilling process design and chip removal testing are also discussed.

Nonoperative Management of Femoroacetabular Impingement: A Prospective Study

Background: The literature has given little attention to the nonoperative management of femoroacetabular impingement (FAI) syndrome despite a rapidly expanding body of research on the topic. Purpose: To perform a prospective study utilizing a nonoperative protocol on a consecutive series of patients presenting to our clinic with FAI syndrome. Study Design: Cohort study; Level of evidence, 2. Methods: Between 2013 and 2016, patients meeting the following criteria were prospectively recruited in a nonoperative FAI study: no prior hip surgery, groin-based pain, a positive impingement test, and radiographic FAI syndrome. The protocol consisted of an initial trial of rest, physical therapy, and activity modification. Patients who remained symptomatic were then offered an image-guided intra-articular steroid injection. Patients with recurrent symptoms were then offered arthroscopic treatment. Outcome scores were collected at 12 and 24 months. Statistical analysis was performed to identify risk factors for the need for operative treatment and to determine patient outcomes based on FAI type and treatment. Results: Ninety-three hips (n = 76 patients: mean age, 15.3 years; range, 10.4-21.4 years) were included in this study and followed for a mean ± SD 26.8 ± 8.3 months. Sixty-five hips (70%) were managed with physical therapy, rest, and activity modification alone. Eleven hips (12%) required a steroid injection but did not progress to surgery. Seventeen hips (18%) required arthroscopic management. All 3 groups saw similar improvements in modified Harris Hip Score (P = .961) and nonarthritic hip score (P = .975) with mean improvements of 20.3 ± 16.8 and 13.2 ± 15.5, respectively. Hips with cam impingement and combined cam-pincer impingement were 4.0 times more likely to meet the minimal clinically important difference in modified Harris Hip Score (P = .004) and 4.4 times more likely to receive surgical intervention (P = .05) than patients with pincer deformities alone. Participants in team sports were 3.0 times more likely than individual sport athletes to return to competitive activities (P = .045). Conclusion: A majority (82%) of adolescent patients presenting with FAI syndrome can be managed nonoperatively, with significant improvements in outcome scores at a mean follow-up of 2 years. Clinical Relevance: A nonoperative approach should be the first-line treatment for young active patients with symptomatic FAI syndrome.

Pincer‐type MRI morphology seen in over a third of asymptomatic healthy volunteers without femoroacetabular impingement

In daily routine, pincer femoroacetabular impingement (FAI) findings are often seen without a clinical diagnosis of pincer FAI. To assess the presence of pincer FAI MRI findings in asymptomatic volunteers with negative impingement test versus patients with clinically confirmed FAI. Case-control study. Sixty-three asymptomatic volunteers and 63 matched patients with FAI were included. A coronal T1 -weighted turbo spin-echo sequence as well as a 3D oblique transverse water-excitation true fast imaging sequence at 1.5T. The volunteers underwent standard MRI of the hip, and patients underwent MR arthrography of the symptomatic hip using the same MR sequences. Measurements of cranial acetabular version, acetabular depth, and lateral center-edge angle were performed independently by three fellowship-trained musculoskeletal radiologists. Descriptive statistics, Mann-Whitney U-test, Unpaired t-test, receiver operating characteristics (ROC), Intraclass correlation coefficient (ICC). Forty-one percent (26/63, reader 1), 32% and 37% (20 and 23/63, reader 2/3) of asymptomatic volunteers had at least one positive MR finding for pincer-FAI. Patients with pincer or mixed-type FAI had cranial retroversion of the acetabulum of -0.2° ± 7.1 (mean ± standard deviation) for reader 1 and -0.3° ± 5.5/-0.2° ± 4.8 for reader 2 / reader 3, while asymptomatic volunteers had an anteversion of 6.2° ± 6.4 (reader 1) and 3.2° ± 4.9/3.1° ± 6.5 (readers 2/3): This difference was statistically significant (P ≤ 0.002), but there was a large overlap between the groups. Acetabular depth measurements were very similar for patients with either pincer or mixed-type FAI (5.1-5.3 mm ± 3.1) and volunteers (5.2-6.1 mm ± 2.6), without a statistically significant difference (P ≤ 0.50). Lateral center-edge angle was also similar in patients with either pincer or mixed-type FAI (32.1-35.1° ± 9.1) and volunteers (30.7-33.2° ± 6.5), without a statistically significant difference (P ≤ 0.28). There is a large overlap in pincer-type MRI findings between patients with symptomatic FAI and asymptomatic volunteers. More than a third of volunteers exhibited at least one positive pincer-type MRI finding. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1296-1303.

CLINICAL AND ROENTGENOLOGICAL CRITERIA OF SPINE-PELVIS RATIOS IN CHILDREN WITH DYSPLASTIC FEMUR SUBLUXATION

Aim of the study — to identify clinical and roentgenological criteria of the sagittal profile status of spine-pelvis segment in children with dysplastic femur subluxation.Material and Methods. The present study included 40 female patients (50 hip joints) aged from 12 to 17 years (14.7±1.58) with unilateral and bilateral hip joint instability due to dysplasia. Children were divided into two groups – the first group included 30 patients (30 hip joints) with unilateral femur subluxation, the second group – 10 patients (20 hip joints) with bilateral femur subluxation. All patients underwent a standard orthopaedic clinical examination using a specialized scale to objectify complaints. All patients underwent X-ray examination of hip joints in AP and Lauenstein projections, CT scanning as well as lateral panoramic roentgenography of C1-S1 including femoral bones in standing position of the patient.Results. The authors observed a strong positive correlation between sacrum inclination and lumbar lordosis curvature, antetorsion angle of proximal femur and sacrum inclination angle, severity of pain syndrome during impingement test and sacrum tilt: Pearson correlation coefficient was 0.71, 0.81 and 0.88 respectively. The authors reported in all patients a thoracic normokyphosis and lumbar hyperlordosis with excessive pelvis anteversion. Global sagittal disbalance was observed in all patients.Conclusion. Apart from typical anatomical and roentgenological changes in pelvic and femoral componentsof the joint the children with dysplastic femur subluxation are characterized by excessive pelvic anteversion. Criteria of above parameters are identical and do not depend on the number of joints involved into the pathological process. Cranial dislocation of femoral head results to abnormalities of sagittal spine-pelvis ratios. Pathological process in hip joints and abnormality of spine-pelvis ratios results in negative changes of sagittal spine profile in the form of hyperlordosis, of physiological criteria of thoracic kyphosis and of the global sagittal disbalance. All of the above leads to overload of spinal motion segments and development of spine degenerative and dystrophic changes at early age.

Periacetabular Osteotomy Improves Pain and Function in Patients With Lateral Center-edge Angle Between 18° and 25°, but Are These Hips Really Borderline Dysplastic?

AbstractBackgroundThe treatment of mild or borderline acetabular dysplasia is controversial with surgical options including both arthroscopic labral repair with capsular closure or plication and periacetabular osteotomy (PAO). The degree to which improvements in pain and function might be achieved u

Visualization Investigation of the Influence of Chamber Profile and Injection Parameters on Fuel Spray Spreading in a Double-Layer Diverging Combustion Chamber for a DI Diesel Engine

The double-layer diverging combustion chamber (DLDC chamber) aims to improve the fuel–air mixing formation and promote in-cylinder air utilization by changing fuel spray spreading characteristics. In order to investigate how the DLDC chamber profile and injection parameters affect the fuel spray spreading, visualization of fuel injection and impingement tests were carried out on two different DLDC chambers with different fuel injection parameters. The visualization test results showed that double-layer fuel spray spreading was obtained in the two DLDC chambers and the peripheral top clearance of each chamber was utilized efficiently. The DLDC chamber with a 50% upper layer volume provided a larger fuel spray distribution region after the start of injection. The DLDC chamber with a 70% upper layer volume obtained a larger fuel spray distribution region with better top clearance utilization at the later stage of injection. The injection parameters mentioned in this research showed significant effects on the fuel spray spreading in the DLDC chamber. Increasing the injection pressure provided a larger fuel spray distribution area at the beginning of injection. Decreasing the nozzle hole diameter had a positive influence on obtaining a larger fuel spray distribution. Advancing the injection timing enabled the enlarging of the fuel distribution region.