Size Of Labrum Research Articles

Poster 185: The Effect of Labrum Size on Cartilage Mechanics in a Patient with Cam-Type Femoroacetabular Impingement Syndrome

Poster 185: The Effect of Labrum Size on Cartilage Mechanics in a Patient with Cam-Type Femoroacetabular Impingement Syndrome

The narrow subspine space and relatively large labrum are radiographic features of subspine impingement: a case-control study

BackgroundSubspine impingement is considered a source of residual hip symptoms after primary hip arthroscopy, and the role of the subspine space and soft tissue is not clear. The purpose of this study was to analyze the relationship between the subspine space and labrum size in subspine impingement patients.MethodsWe performed a retrospective study of patients with femoroacetabular impingement between July 2016 and July 2020. Sixteen patients without hip symptom relief after primary hip arthroscopic treatment of femoroacetabular impingement and undergoing revision surgery for anterior inferior iliac spine compression were included as the study group. Forty-eight matched patients who underwent only primary surgery and whose hip discomfort was relieved without a diagnosis of subspine impingement were included as the control group. The patients’ preoperative computerized tomography data were reviewed, and the anterior inferior iliac spine dimensions and the size of the subspine space were measured. The size of the labrum at the 11:30, 1:30, and 3 o’clock positions was measured with the use of magnetic resonance imaging. The ratio of the subspine space to the labrum was also calculated.ResultsThere was no significant difference in anterior inferior iliac spine dimensions between these two groups (p > 0.05). A relatively narrow subspine space was found in the study group, especially in the direction of the anterior inferior iliac spine. Compared with the control group, subspine impingement patients were identified with larger labrums at 11:30 (8.20 ± 1.95 mm vs. 6.81 ± 0.50 mm, p = 0.016), 1:30 (7.83 ± 1.61 mm and 6.25 ± 0.78 mm, p = 0.001) and 3:00 (9.50 ± 1.73 mm vs. 7.48 ± 0.99 mm, p = 0.001). A relative mismatch between the subspine space and the labrum was also identified in the study group. The ratios of the labrum width to the subspine area were significantly larger in the study group than in the control group.ConclusionThis study reported potential additional criteria for subspine impingement—a large labrum and a relatively narrow subspine space—instead of abnormal anterior inferior iliac spine dimensions. For those with a large labrum and narrow subspine space, the diagnosis of subspine impingement should be carefully made, and arthroscopic anterior inferior iliac spine decompression may be important.

The correlation between the labrum size and the labral tear in asymptomatic volunteers and symptomatic patients

BackgroundSome studies have proved that labrum size is associated with symptoms in patients with hip labral tear. The correlation between the labrum size and the labral tear in asymptomatic volunteers and symptomatic patients is still uncertain.MethodsThe volunteers with no history of pain, injury, or surgery were recruited from the community. Patients who were diagnosed with labral tear and underwent hip arthroscopic surgery in this period in our hospital were also included. The length and height of the acetabular hip labrum were measured at three separate anatomic sites through magnetic resonance imaging (MRI) along the acetabular rim: lateral, anterior, and anteroinferior.ResultsA total of 70 volunteers (125 hips) and 70 patients (70 hips) were included in this study. Sixty-six (52.8%) hips had labral tears in all 125 hips of volunteers. The lateral labral length of volunteers with labral tears was significantly larger than those without labral tears (P < .05). In 14 volunteers with unilateral labral tears, length of lateral, anterior, and anteroinferior labrum in the side with tear were significantly larger than normal on the other side. The anterior labral height of volunteers was significantly larger than that of patients (P < .05).ConclusionsIn conclusion, asymptomatic volunteers with larger length of lateral, anterior, and anteroinferior labrum are more prone to present with labral tears. Symptomatic patients with labral tears exhibited thinner anterior labrum. Further studies are warranted to explore the mechanisms of labral tears in asymptomatic people and validate the use of labral size as a guide to differential diagnosis and treatment.

The dimensions of the hip labrum can be reliably measured using magnetic resonance and computed tomography which can be used to develop a standardized definition of the hypoplastic labrum.

The purpose of this study was to examine the existing literature to determine the dimensions of the acetabular labrum, with a focus on hypotrophic labra, including the modalities and accuracy of measurement, factors associated with smaller labra, and any impacts on surgical management. Four databases (PubMed, Ovid [MEDLINE], Cochrane Database, and EMBASE) were searched from database inception to January 2020. Two reviewers screened the literature independently and in duplicate. Methodological quality of included papers was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria.Where possible, data on labral size were combined using a random effects model. Twenty-one studies (5 level II, 9 level III, 7 level IV) were identified. This resulted in 6,159 patients (6,436 hips) with a mean age of 34.3years (range 8.4-85). The patients were 67.3% female with an average follow-up of 57.3months. There was no consistent definition of labral size quoted throughout the literature. The mean width on MRI/MRA was 7.3mm (95% CI 6.9-7.8mm), on computed tomography arthrography was 8.7mm (95% CI 8.0-9.3), and during arthroscopy was 5.0mm (95% CI 4.9-5.2). Inter-observer reliability was good to excellent in all modalities. Labral hypotrophy may be associated with increased acetabular coverage. Hypertrophic labra were highly associated with acetabular dysplasia (r = -0.706, -0.596, -0.504, respectively; P < 0.001). Labral width can reliably be measured utilizing imaging techniques including magnetic resonance and computed tomography. The pooled mean labral width was 6.2mm, and height 4.6mm. The establishment of a gold-standard of measurement on arthroscopy and advanced imaging would aid in clinical decision-making regarding treatment options for patients presenting with a painful hip, particularly those with hypoplastic labra, and provide radiological guidelines for standardized labrum size classifications. Level IV.

Patients with a Hypoplastic Labrum Achieve Similar Outcomes After Primary Labral Repair in the Treatment of Femoracetablular Impingement Syndrome Compared to Patients with a Normal Labrum

Objectives:A preoperative or intraoperative finding of an acetabular labrum width of <4mm is often cited as an indication for performing primary labral reconstruction over repair in the surgical correction of Femoracetablular Impingement Syndrome (FAIS). The purpose of this study is to compare patient reported clinical outcomes and rates of reaching Minimum Clinical Important Differences (MCID) and Patient Acceptable Symptomatic State (PASS) between patients with a hypoplastic labrum compared to those with a normal labrum width at a minimum 1 year from arthroscopic treatment of FAIS.Methods:Data from consecutive patients who underwent primary hip arthroscopy between November 2015 and July 2018 for the treatment of FAIS were analyzed. Baseline demographic data, preoperative, and minimum 1 year post-operative clinical outcomes including Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool 12 questions (iHOT-12), and visual analog scale (VAS) for pain and satisfaction were recorded. The labrum size was documented by the senior surgeon for all patients using the tip of an arthroscopic probe measuring 4mm. Labrum hypoplasia was defined as a labrum width at the 12 o’clock position of <4mm and normal labrum was defined as labrum width between 4 and 7mm. Patients with hypoplastic labrum were matched 1:1 by age and BMI to patients with normal labrum width. All patients underwent arthroscopic labral repair in addition to impingement resection and capsular repair. The groups were further compared after separating by acetabular coverage, in which a Lateral Center Edge Angle of 18-24.9 was considered borderline dysplastic and 25-40 was considered normal. Rates of achieving MCID calculated using a distribution-based method and PASS calculated using an anchor-based method.Results:A total of 360 patients were included in the study with 180 in each of the normal and hypoplastic groups. There was no significant differences seen in 1-year post operative outcome scores or score improvement between the two groups. When examining only borderline dysplastic patients there were no significant differences in outcomes between normal and hypoplastic labrum patients. In the subset with a normal LCEA only post-operative VAS satisfaction (85.5 ± 19.3 vs 78.2 ± 27.4; p=0.050) was significantly higher in the normal labrum patients compared to hypoplastic labrum. Patients with hypoplastic labrum achieved MCID and PASS at the same rate as patients with normal labrum across all outcome measures.Conclusions:Patients with an intraoperative finding of labral hypoplasia achieve 1-year meaningful clinical outcome at the same rate as those with normal labral width following arthroscopic labral repair. These results bring into question the need for primary labral reconstruction in patients with labral hypoplasia with a normal or borderline dysplastic acetabulum.

Patients With a Hypotrophic Labrum Achieve Similar Outcomes After Primary Labral Repair Compared With Patients With a Normal-Sized Labrum: A Matched Cohort Analysis of 346 Patients With Femoroacetabular Impingement Syndrome

To compare patient functional scores and rates of achieving minimum clinically important differences (MCID) and patient acceptable symptomatic state (PASS) between patients with a hypotrophic labrum with those with a normal labrum width at a minimum 1-year follow-up from arthroscopic treatment of femoroacetabular impingement syndrome. Data from consecutive patients who underwent primary hip arthroscopy between November 2015 and July 2018 for the treatment of femoroacetabular impingement syndrome were analyzed. Baseline demographic data, preoperative patient-reported outcome measures (PROMs), and minimum 1-year PROMs, including Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool 12 questions, and visual analog scale for pain and satisfaction were recorded. The labrum size was determined using an arthroscopic probe at the 12- to 2-o'clock position with a hypotrophic labrum being defined as <4 mm and normal labrum defined as having a width between 4 and 7 mm on the articular side. Patients with hypotrophic labrum were matched 1:1 by age and body mass index to patients with normal labrum width. A total of 346 patients were included in the study with an average age of 31.4 ± 11.9 and a majority being female (72.0%). There were 173 in each of the normal and hypotrophic groups. There were no significant differences seen in 1-year PROMs between the 2 groups (P > .05 for all). The normal labrum group achieved MCID at a rate of 75% to 84% and PASS at a rate of 51% to 70%. The hypotrophic labrum group achieved MCID at a rate of 70% to 85% and PASS at a rate of 57% to 71%. There were no significant differences in rates between each group (P > .05 for all). Patients with an intraoperative finding of labral hypotrophy achieve 1-year meaningful clinical outcome at the same rate as those with normal labral width following arthroscopic labral repair. III, Case-control study.

Is labral hypotrophy correlated with increased acetabular depth?

Labral hypertrophy is a distinct feature in hip dysplasia. Occasionally, very small, hypotrophic labra are observed. However, there is no literature concerning this pathology. We investigated if the size of the labrum correlated with any radiologic parameters reflecting the amount of acetabular coverage. It was hypothezised that there is a negative correlation between labrum size and acetabular coverage. Labra were categorized into three groups depending on the relation between length of the articular sided surface and height of bony attachment. Labra with a height:length ratio of 2 were classified as hypotrophic, with a height:length ratio of 1 as normal and with a ratio of 0.5 as hypertrophic. Labral cross-sectional areas (CSA) were measured on radial magnetic resonance imaging-arthrography slices using the measuring tool of the PACS system of 20 hips with hypotrophic labra (group 1), 20 hips with normal labral appearance (group 2) and 10 hips with hypertrophic labra (group 3). These values were then analyzed against following parameters: neck-shaft-angle (NSA), lateral center-edge angle (LCE), acetabular index (AI), femoral extrusion index (FEI) and acetabular retroversion index (ARI). Analyses of variance were used to determine differences in mean values between the three groups. Mean labral CSA differed significantly between all groups (group 1: 12.1 ± 2.9 mm2; group 2: 25.2 ± 6.2 mm2; group 3: 41.1 ± 12.3 mm2; P < 0.001). NSA, LCE, AI and FEI all showed a significant difference between group 3 and 1 or 2. The ARI showed no difference between groups. Stepwise linear regression analyses showed a significant correlation between LCE angle and labral CSA with a corrected R2-value of 0.301. Labral CSA correlates with the LCE. No statistically significant difference between groups 1 and 2 concerning the LCE, AI or FEI could be identified. Nevertheless, group 1 had the highest mean coverage of all groups, hips with hypertrophic labra the lowest.

Dietary diversification and variations in the number of labrum sensilla in grasshoppers: Which came first?

The diversity of the diet of grasshoppers (Acrididae, Orthoptera) is related to multiple factors, including the chemoreceptors on the antennae, palps and on the epipharyngeal face of the labrum. In the present study, we sought to understand the nature of the diet of 12 Moroccan acridian species and to try to relate various aspects of their diet to the number of labrum sensilla. If the effect of the labrum size on the number of sensilla is removed, four groups of species are recorded: (i) polyphagous species with a broad diet and numerous sensilla; (ii) polyphagous species with a graminivorous diet and numerous sensilla; (iii) oligophagous species feeding exclusively on Poaceae and with a medium number of sensilla; and (iv) strictly monophagous species feeding on a single plant species and with the smallest number of sensilla. These observations show the close relationship between the diet and the number of labrum sensilla. However, Sphingonotus rubescens, a polyphagous species, is an exception to this trend as it harbours a medium number of sensilla. We propose that the modification in the number of labrum sensilla is a result of a progressive adaptation to a different diet and does not represent its cause.

Mouthparts of Three Collembolan Species: Comparative Morphology

The mouthparts (labrum, mandibles, and maxillae) of three litter-dwelling collembolan species-Orchesella hexfasciata (Entomobryidae), Isotoma notabilis (Isotomidae), and Sminthurinus henshawi (Sminthuridae)-are described, using both light and scanning electron microscopy. The right molar plate of all three species bears a projection that fits into a corresponding depression on the left molar plate, a previously unnoticed but possibly common and important feature. Based on the free-standing nature of molar plate rods, we suggest a brushing rather than a grinding function. The mouthparts of these species are structurally very similar, but differ in size. Size of labrum and mandibles probably dictates the size of food particles ingested. The rake-like structure of lamella 1 on the maxillar head of L. notabilis may explain why the gut contents of this species consist largely of colloidal material. Additional key words: labrum, mandible, maxilla, Orchesella, Isotoma, Sminthurinus Collembolans are dominant arthropods in terrestrial detritus-based food webs, both in terms of population density and species richness. They have an integral role in maintaining and shaping microbial activity and community structure, and are important mediators of food web stability (Moore et al. 1988). The functional importance of collembolans in decomposition processes is closely associated with their feeding activities (Seastedt 1984). Some significant contributions on the structure and function of collembolan mouthparts include Folsom (1899, 1900), Hoffman (1905, 1908), Borner (1908, 1909), Denis (1928), Wolter (1963), Manton (1964), Goto (1972), and Chaudonneret (1973). Although the link between mouthpart structure and feeding habits has long been recognized (MacNamara 1924; Fjellberg 1985), no attempt has been made to investigate the relationship between detailed mouthpart morphology and food selection. During an investigation of food partitioning in litter-dwelling collembolans (Chen et al. 1996), we studied the morphology of the labrum, mandibles, and maxillae of three collembolan species common in deciduous forest, using both light and scanning electron microscopy. Collembolans possess an entognathous mouth, mandibles and maxillae being enclosed by the head capsule. Two general mouth types are recognized, depending on whether mandibular molar plates are present (chewing type) or absent (sucking type). Collembolans a Author for correspondence. E-mail: 23118MGR@msu.edu with mandibular molar plates use their mouthparts (mainly mandibles and maxillae) to chew, grind, and/or tear food material before ingesting it. The tips of the mandibles can scratch the food surface, and mandibles and maxillae can also reach out, grasp, and carry food back into the mouth. Movement of mandibles and maxillae is restricted by surrounding structures such as labrum, labium, and the lateral margins of the gnathal pouch (Manton 1964). Shape and size of mandibles and labrum may restrict type and particle size of ingested food (Fjellberg 1985). Although constructed according to the same general model, the feeding apparatus varies among species even in closely related groups (Fjellberg 1984).