Computed tomography-based abdominal sarcopenic indices and bio-impedance analysis-based skeletal muscle mass index in hemodialyzed patients.

BACKGROUND AND AIMS: Information about muscle wasting in hemodialyzed patients evaluated using computed tomography (CT) is limited. The present study aimed to examine the relationships between CT-based abdominal sarcopenic indices and bio-impedance analysis (BIA)-based skeletal muscle mass index (SMMI) in these patients. METHODS: A total of 100 consecutive maintenance hemodialyzed patients who underwent CT and BIA were included. The psoas muscle index (PMI), paraspinous muscle index (PSMI), and abdominal skeletal muscle index (ASMI) were calculated by adjusting each muscle area to the height square. The psoas muscle thickness per height (PMTH) was measured using a single cross-sectional CT image obtained at the level of the third lumbar vertebra. The relationships between these CT-based sarcopenic indices and the BIA-based SMMI were examined. Moreover, the diagnostic values of these CT-based indices for BIA-defined muscle wasting (defined by the sex-specific SMMI: males, <7.0 kg/m2; females, <5.7 kg/m2) were investigated. RESULTS: The PMI, PMTH, PSMI, and ASMI were significantly correlated with the SMMI (r = 0.678, 0.760, 0.708, and 0.785, respectively; p < 0.0001 for all). Twenty-eight patients with reduced muscle mass determined by BIA were identified. After age-sex adjustment, a multivariate logistic regression analysis revealed that the C-statistics of the PMI, PMTH, PSMI, and ASMI for the diagnosis of low muscle mass were 0.863 (p = 0.0099), 0.870 (p = 0.013), 0.891 (p = 0.040), and 0.950 (reference), respectively. CONCLUSIONS: CT-based abdominal sarcopenic indices presented here may be useful for evaluating muscle wasting in hemodialyzed patients; the ASMI may be the most recommended sarcopenic index for such evaluations.

Association between lumbar intervertebral vacuum phenomenon severity and posterior paraspinal muscle atrophy in patients undergoing spine surgery.

PURPOSE: Intervertebral vacuum phenomenon (IVP) and paraspinal muscular atrophy are age-related changes in the lumbar spine. The relationship between both parameters has not been investigated. We aimed to analyze the correlation between IVP and paraspinal muscular atrophy in addition to describing the lumbar vacuum severity (LVS) scale, a new parameter to estimate lumbar degeneration. METHODS: We analyzed patients undergoing spine surgery between 2014 and 2016. IVP severity was assessed utilizing CT scans. The combination of vacuum severity on each lumbar level was used to define the LVS scale, which was classified into mild, moderate and severe. MRIs were used to evaluate paraspinal muscular fatty infiltration of the multifidus and erector spinae. The association of fatty infiltration with the severity of IVP at each lumbar level was assessed with a univariable and multivariable ordinal regression model. RESULTS: Two hundred and sixty-seven patients were included in our study (128 females and 139 males) with a mean age of 62.6 years (55.1-71.2). Multivariate analysis adjusted for age, BMI and sex showed positive correlations between LVS-scale severity and fatty infiltration in the multifidus and erector spinae, whereas no correlation was observed in the psoas muscle. CONCLUSION: IVP severity is positively correlated with paraspinal muscular fatty infiltration. This correlation was stronger for the multifidus than the erector spinae. No correlations were observed in the psoas muscle. The lumbar vacuum severity scale was significantly correlated with advanced disc degeneration with vacuum phenomenon.

Acute muscle wasting is associated with poor prognosis in older adults with severe community-acquired pneumonia.

PURPOSE: To investigate the impact of acute muscle wasting on 90-day mortality in older patients with severe pneumonia using ultrasound and chest computed tomography (CT). METHODS: Quadriceps muscle layer thickness was measured via ultrasound on days 1, 7, and 14, and cross-sectional area of the erector spinae muscle was assessed using chest CT on days 1 and 14 in patients aged ≥ 65 years old. The primary outcome was all-cause 90-day mortality. Receiver operating characteristic curves were conducted for muscle loss to predict 90-day mortality. Cox proportional hazard models and Kaplan-Meier survival curves were employed to evaluate the association between muscle loss and 90-day mortality. RESULTS: Sixty-two patients were enrolled with median age of 80.2 years, 29 (46.8%) were men and 28 (45.2%) patients died. Muscle mass measured using ultrasound and CT decreased significantly from baseline to day 14 in the non-survivor group. Muscle loss assessed by ultrasound (with minimum and maximum pressure) and CT independently predicted all-cause 90-day mortality (adjusted hazard ratios = 1.497, 1.400 and 1.082; P < 0.001, P = 0.002, and P = 0.004; respectively), and cutoff values of muscle loss were 0.34 cm, 0.11 cm and 4.92 cm2, correspondingly. A higher muscle loss had an increased risk of 90-day mortality. CONCLUSIONS: Acute muscle wasting assessed by ultrasound and chest CT persisted for 14 days and was an independent predictor of adverse outcomes in older patients with severe pneumonia. A greater decline in muscle mass was associated with a higher 90-day mortality risk.

The validity of ultrasound and shear wave elastography to assess the quality of the rotator cuff.

OBJECTIVES: US with shear wave elastography (SWE) could reduce the burden and costs of the diagnostic process for patients with rotator cuff disorders. The aim of this study is to investigate the validity of US and SWE in preoperative assessment of fatty infiltration (FI) and muscle atrophy of the supraspinatus (SSP) and infraspinatus (ISP) muscles. METHODS: Patients with a rotator cuff disorder and a recent shoulder CT or MRI scan were eligible to participate. Goutallier and Warner stages of the SSP and ISP muscle were measured on the scan, for assessment of FI and muscle atrophy, respectively. These findings were compared with shear wave velocities (SWVs) assessed on US. Visual assessment of FI on US was compared with the Goutallier stage. To quantify the amount of muscle atrophy, the occupation ratio between SSP fossa and muscle was measured on MRI and US. RESULTS: Seventy-eight shoulders were included in the analysis. The correlation found between the occupation ratio on US and Warner and Goutallier stage and ratio on MRI ranged between r = - 0.550 to 0.589. The Goutallier stage of ISP and SSP muscle assessed on US showed a fair correlation with the Goutallier stage on a scan of r = 0.574 and r = 0.582, respectively. There was a poor correlation between the SWVs and scan results (r = - 0.116 to 0.07). CONCLUSION: SWE is not a valid method to measure the amount of FI or muscle atrophy in the SSP muscle. Therefore, SWE is not a suitable alternative for MRI in standard preoperative diagnostics in rotator cuff pathologies. CLINICAL RELEVANCE STATEMENT: Shear wave elastography should not be used in the diagnostics of rotator cuff pathologies. KEY POINTS: • There is a fair correlation between the Goutallier stage of the supraspinatus and infraspinatus muscle assessed on MRI and CT and visual assessment of fatty infiltration achieved on US. • Shear wave elastography is not a valid tool for the determination of the amount of fatty infiltration or muscle atrophy. • Shear wave elastography should not be used as a cheaper and less burdensome alternative for diagnostics in rotator cuff pathologies.

Longitudinal Changes in Quadriceps Morphology over the First 3 Months after Anterior Cruciate Ligament Reconstruction.

PURPOSE: Neuromuscular deficits and atrophy after anterior cruciate ligament reconstruction (ACLR) may be accompanied by changes in muscle composition and poor quadriceps muscle quality (QMQ). Quadriceps atrophy occurs after ACLR but improves within the first three postoperative months, yet this hypertrophy could be attributable to increases in noncontractile tissue (i.e., poor QMQ). The purposes of this study were to evaluate changes in QMQ after ACLR and to determine if changes in QMQ and cross-sectional area (CSA) occur in parallel or independently. METHODS: A longitudinal prospective cohort design was implemented to evaluate QMQ and CSA in 20 individuals with ACLR and 12 healthy controls. Participants completed three testing sessions (baseline/presurgery, 1 month, and 3 months) during which ultrasound images were obtained from the vastus lateralis (VL) and rectus femoris (RF). QMQ was calculated as the echo intensity (EI) of each image, with high EI representing poorer QMQ. Anatomical CSA was also obtained from each image. RESULTS: RF and VL EI were greater at 1 and 3 months in the ACLR limb compared with baseline and the contralateral limb and did not change between 1 and 3 months. VL and RF CSA in the ACLR limb were smaller at 1 and 3 months compared with the contralateral limb and controls (VL only) but increased from 1 to 3 months. Changes in QMQ and CSA were not correlated. CONCLUSIONS: QMQ declines within the first month after ACLR and does not improve by 3 months although hypertrophy occurs, suggesting that these morphological characteristics change independently after ACLR. Poorer QMQ represents greater concentration of noncontractile tissues within the muscle and potentially contributes to chronic quadriceps dysfunction observed after ACLR.

Proposal of a diagnostic algorithm for radiation-induced dropped head syndrome in long-term childhood cancer survivors based on a prospective study in a specialized clinical setting and a review of the literature.

PURPOSE: To prospectively assess the incidence of Dropped Head Syndrome (DHS) in childhood cancer survivors (CCS) and to develop and evaluate a diagnostic algorithm for DHS. METHODS: A systematic literature search for DHS in combination with neck radiotherapy (RT) exposure was performed. Analyses and a combination of the most common examination methods were integrated into a diagnostic algorithm. Almost all CCSs visiting the local late effects clinic between May 2020 and April 2022 were included in the study. CCS exposed to neck RT with doses ≥ 19 Gy received standardized clinical and neurological assessment and, in case of abnormal results, an MRI scan to confirm muscle atrophy. RESULTS: Two hundred and five CCS were included of whom 41 received RT to the neck with ≥ 19 Gy. In the entire cohort and in the subgroup receiving RT, 2.4% and 12% of CCS were affected by DHS, respectively. Results of clinical and neurological assessment correlated well with MRI results. Neck circumference and neck/thigh ratio were lower after neck RT. Over 50% of CCS experienced neck disability and pain. CONCLUSIONS: A relevant proportion of CCS exposed to neck RT is affected by DHS. High concordance of MRI results with the neurological examination supports the clinical value of the diagnostic algorithm. Measurement of neck circumference might be an easy tool for assessment of neck muscle atrophy in survivors at risk. IMPLICATIONS FOR CANCER SURVIVORS: Integration of a diagnostic algorithm for DHS in standard long-term follow-up care facilitates diagnosis as well as initiation of early treatment and obviates the need for invasive examinations.

Ultrasound assessment of muscle mass and correlation with clinical outcomes in critically ill patients: a prospective observational study.

PURPOSE: Muscular atrophy implies structural and functional alterations related to muscular force production and movement. This condition has been reported to be the main reason for generalized muscle weakness; it reflects the severity of the disease and can have a profound impact on short- and long-term clinical outcomes. The purpose of this study was to determine whether muscle atrophy ultrasound parameters early predict muscle weakness, morbidity, or 28-days mortality. METHODS: This was a prospective, observational single center cohort study. Ultrasound was used to determine the cross-sectional area and muscle thickness of the rectus femoris on the first and third day of ICU stay. The main outcome was the incidence of significant muscle atrophy (≥ 10%). RESULTS: Ultrasound measurements were made in 31 patients, 58% (18/31) of which showed significant muscle atrophy. The relative loss of muscle mass per day was 1.78 at 5% per day. The presence of muscle atrophy presents increased risk for limb muscle weakness and handgrip weakness. The 28-days mortality rate was similar in both subgroups. CONCLUSION: The presence of muscle atrophy presents an increased clinical risk for the development of limb ICUAW and handgrip, although these observations were not statistically significant. The results could be used to plan future studies on this topic.

Thigh ultrasound monitoring identifies muscle atrophy in mechanically ventilated pediatric patients.

Over the last decade, ultrasonography has taken on an increasingly important role in the daily management of critically patients and has recently been proposed as a means of measuring muscle volume and architecture. This study had two main aims: to monitor for the onset of muscle atrophy in mechanically ventilated pediatric patients during stays in a pediatric intensive care unit based on quadriceps femoris muscle thickness measurements and to study whether demographic and clinical variables have an impact on muscle loss in critically children. The study followed a prospective, observational, single-center design. The sample included all children admitted to our pediatric intensive care unit (PICU) who required mechanical ventilation for more than 48 h. Two trained clinicians measured the thickness of the quadriceps using a 12-MHz linear ultrasound transducer within 24 h of initiating invasive mechanical ventilation and again at 72 h, 1 week, and weekly thereafter until extubation. For the entire cohort, quadriceps femoris muscle thickness decreased by 4.67% on average (IQR = -13.4 to -0.59) between the first two assessments and 13% by the time of the final measurement (IQR = -24 to -0.5%) or 1.57%/day (p < 0.001). Approximately half of all the children (23/41; 56%) experienced muscle atrophy (defined a priori as a decrease in thickness of 10% or more). Bivariate analyses revealed that increasing age, being a child (vs. infant), cumulative energy and protein deficit, highest C-reactive protein value, exposure to neuromuscular blockers, and a longer stay in the PICU were all predictive of a greater decrease in thickness. In a multivariate model, exposure to neuromuscular blockers was linked with greater muscle loss.       Conclusion: In mechanically ventilated children, point-of-care ultrasonography can identify skeletal muscle atrophy. Muscle atrophy of limbs is strongly associated with the use of neuromuscular blockers. Ultrasound-based monitoring of the quadriceps femoris is a clinically useful tool for assessing muscle mass that can provide information on nutritional status and guide rehabilitation. What is Known: • ICU-acquired muscle atrophy is common and has a deleterious effect on adult outcomes. The prevalence and severity of muscular atrophy in critically ill children, however, are poorly understood. • Point-of-care ultrasonography has been put forward as an accurate, reliable method for monitoring variations in muscle mass.. What is New: • The quadriceps femoris muscle tends to suffer an intense loss of thickness early on in most critically ill children. • Quadriceps femoris ultrasound monitoring is a helpful tool for measuring muscle thickness and could lead to the development of novel therapies for critically ill children.

Characteristics of paraspinal muscle degeneration in patients with adult degenerative scoliosis.

INTRODUCTION: Adult degenerative scoliosis (ADS) is a 3D deformity that greatly affects the quality of life of patients and is closely related to the quality of paraspinal muscles (PSMs), but the specific degenerative characteristics have not been described. METHODS: This study included ADS patients who were first diagnosed in our hospital from 2018 to 2022. Muscle volume (MV) and fat infiltration (FI) of PSM were measured by 3D reconstruction, and spinal parameters were assessed by X-ray. The values of convex side (CV) and concave side (CC) were compared. RESULTS: Fifty patients were enrolled with a mean age of 64.1 ± 5.8 years old. There were significant differences in MV, FI, and Cobb angle between male and female groups. The MV of MF and PS on the CC was significantly larger than that on the CV. In the apex and the segments above the apex, the FI of the MF on the CC is greater than the CV, and in the CV of the segment below the apex, the FI of the MF is greater than the CC. Besides, there was a significant positive correlation between the FI and Cobb angle in the MF of the CC-CV. CONCLUSION: There were significant differences in the MV and FI of PSM on both sides of the spine in ADS patients. It was determined that the PSM of ADS showed different degrees of degeneration in different levels of the lumbar spine and were positively correlated with Cobb angle.

Association Between Supraspinatus Tendon Retraction, Histologic Myofiber Size, and Supraspinatus Muscle Atrophy on MRI.

BACKGROUND: Atrophy of the rotator cuff is a negative prognostic indicator after rotator cuff repair. Although full-thickness rotator cuff tears accompanied by tendon retraction are commonly associated with decreased muscle cross-sectional area (CSA) on magnetic resonance imaging (MRI), it is unclear whether this is accompanied by histologic atrophy of rotator cuff myofibers. PURPOSE: To evaluate the effect of supraspinatus tendon retraction and myofiber size on supraspinatus atrophy on MRI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Supraspinatus muscle biopsy specimens were obtained from consecutive patients undergoing arthroscopic shoulder surgery. Rotator cuff tears were classified according to size. Preoperative MRI was used to measure tendon retraction and CSA of the supraspinatus muscle in the Y-shaped view. The occupation ratio of the supraspinatus was calculated by dividing the supraspinatus CSA by the supraspinatus fossa CSA. Muscle biopsy specimens were examined using laminin to quantify myofiber CSA. The association between supraspinatus tear size and measures of histologic and MRI muscle atrophy were compared using standard statistical tests. Multivariable logistic regression analysis was used to identify independent predictors of muscle atrophy on MRI. RESULTS: A total of 38 patients were included: 8 with no tear, 14 with a partial-thickness tear, and 16 with a full-thickness tear. Increasing tear size was associated with greater distance of tendon retraction (P < .001), smaller mean histologic myofiber size (P = .004), lower mean supraspinatus CSA on MRI (P < .001), and lower occupation ratio: 0.73 (control), 0.66 (partial tear), 0.53 (small to medium full-thickness tear), and 0.38 (large to massive full-thickness) (P < .001). On Pearson correlation analysis, tendon retraction demonstrated strong correlation with occupation ratio (-0.725; P < .001) and weak correlation with myofiber size (-0.437; P = .006), while occupation ratio showed moderate correlation with myofiber size (0.593; P < .001). Multivariable linear regression analysis demonstrated that increasing tendon retraction (P < .001), age (P = .034), and smaller histologic myofiber CSA (P = .047) were independently associated with greater supraspinatus atrophy on MRI. CONCLUSION: Supraspinatus muscle atrophy appreciated on MRI is independently associated with patient age, tendon retraction, and atrophy of the supraspinatus myofibers at the histologic level.

Intact revision rotator cuff repair stabilizes muscle atrophy and fatty infiltration after minimum follow up of two years.

BACKGROUND: The extent of fatty infiltration and rotator cuff (RC) atrophy is crucial for the clinical results after rotator cuff repair (RCR). The purpose of this study was to evaluate changes in fatty infiltration and RC atrophy after revision RCR and to correlate them with functional outcome parameters. METHODS: Patients who underwent arthroscopic revision RCR for symptomatic recurrent full-thickness tear of the supraspinatus tendon between 2008 and 2014 and were retrospectively reviewed with a minimum follow up of 2 years. Magnetic resonance imaging (MRI) was performed pre- and postoperatively to assess 1) tendon integrity after revision RCR according to Sugaya classification, (2) RC atrophy according to Thomazeau classification, and (3) fatty infiltration according to Fuchs MRI classification. Constant score (CS) and the American Shoulder and Elbow Surgeon (ASES) score were used to correlate functional outcome, tendon integrity, and muscle degeneration. RESULTS: 19 patients (17 males and 2 females) with a mean age of 57.5 years (range, 34 to 72) were included into the study at a mean follow-up of 50.3 months (range, 24 - 101). At final evaluation, 9 patients (47%) presented with intact RCR and 10 patients (53%) suffered a re-tear after revision repair. No progress of fatty infiltration was observed postoperatively in the group with intact RC, atrophy progressed in only 1 out of 9 patient (11%). Fatty infiltration progressed in 5/10 patients (50%) and RC atrophy increased in 2/10 patients (20%) within the re-tear group. CS (42.7 ± 17.7 preop, 65.2 ± 20.1 postop) and ASES (47.7 ± 17.2 preop, 75.4 ± 23.7 postop) improved significantly from pre- to postoperatively (p < 0.001). A positive correlation between fatty infiltration and RC integrity was detected (r = 0.77, p < 0.01). No correlation between clinical outcome and tendon integrity or RC atrophy was observed. CONCLUSION: Arthroscopic revision RCR leads to reliable functional outcomes even in case of a recurrent RC retear. An intact RCR maintains the preoperative state of fatty infiltration and muscle atrophy but does not lead to muscle regeneration. LEVEL OF EVIDENCE: Level IV; Therapeutic study.

Diaphragm thickness by ultrasound in pediatric patients with primary malnutrition.

Skeletal muscle atrophy is known to be a marker for nutritional deficiency. The diaphragm is both a skeletal muscle and a respiratory muscle. There is not enough data in the literature about the change in diaphragm thickness (DT) in children with malnutrition. We think that malnutrition may have negative effects on diaphragm thickness. Therefore, in this study, we aimed to compare the diaphragm thicknesses of pediatric patients with primary malnutrition and a healthy control group. The DT of pediatric patients diagnosed with primary malnutrition by a pediatric gastroenterologist was prospectively evaluated by a radiology specialist by ultrasonography (USG). The obtained data were statistically compared with the data of the healthy control group. There was no statistically significant difference between the groups in terms of age and gender (p = 0.244, p = 0.494). We found that right and left diaphragm thicknesses were significantly thinner in the malnourished group than in the healthy control group (p = 0.001, p = 0.009, respectively). We found that right and left diaphragm thicknesses were thinner in those with moderate and severe malnutrition compared to the normal group (p < 0.001, p = 0.003, respectively). We found a significant weak positive correlation between weight and height Z score and right and left diaphragm thickness (respectively, r: 0.297, p < 0.001; r: 0.301, p < 0.001).   Conclusion: Malnutrition is a disease that affects all systems. Our study shows that the DT is thinner in patients with malnutrition. What is Known: •Malnutrition causes skeletal muscle atrophy. What is New: •Diaphragm muscle thickness decreases in malnutrition. •There is a significant positive correlation between diaphragm muscle thickness and height, weight and BMI z scores.

Muscle atrophy in diabetic patients with Charcot foot: a case-control study.

PURPOSE: To evaluate the distribution and severity of muscle atrophy in diabetic patients with active Charcot foot (CF) compared to diabetic patients without CF. Furthermore, to correlate the muscle atrophy with severity of CF disease. MATERIAL/METHODS: In this retrospective study, MR images of 35 diabetic patients (21 male, median:62.1 years ± 9.9SD) with active CF were compared with an age- and gender-matched control group of diabetic patients without CF. Two readers evaluated fatty muscle infiltration (Goutallier-classification) in the mid- and hindfoot. Furthermore, muscle trophic (cross-sectional muscle area (CSA)), intramuscular edema (none/mild versus moderate/severe), and the severity of CF disease (Balgrist Score) were assessed. RESULTS: Interreader correlation for fatty infiltration was substantial to almost perfect (kappa-values:0.73-1.0). Frequency of fatty muscle infiltration was high in both groups (CF:97.1-100%; control:77.1-91.4%), but severe infiltration was significantly more frequent in CF patients (p-values: < 0.001-0.043). Muscle edema was also frequently seen in both groups, but significantly more often in the CF group (p-values: < 0.001-0.003). CSAs of hindfoot muscles were significantly smaller in the CF group. For the flexor digitorum brevis muscle, a cutoff value of 139 mm2 (sensitivity:62.9%; specificity:82.9%) in the hindfoot was found to differentiate between CF disease and the control group. No correlation was seen between fatty muscle infiltration and the Balgrist Score. CONCLUSION: Muscle atrophy and muscle edema are significantly more severe in diabetic patients with CF disease. Muscle atrophy does not correlate with the severity of active CF disease. A CSA < 139 mm2 of the flexor digitorum brevis muscle in the hindfoot may indicate CF disease.

Facet Joint Orientation/Tropism Could Be Associated with Fatty Infiltration in the Lumbar Paraspinal Muscles.

BACKGROUND: Facet joint orientation (FJO) and facet joint tropism (FJT) are associated with intervertebral disc degeneration and paraspinal muscle atrophy. However, none of the previous studies has evaluated the association of FJO/FJT with fatty infiltration in the multifidus, erector spinae, and psoas muscles at all lumbar levels. In the present study, we aimed to analyze whether FJO and FJT were associated with fatty infiltration in the paraspinal muscles at any lumbar level. METHODS: Paraspinal muscles and FJO/FJT were evaluated from L1-L2 to L5-S1 intervertebral disc levels on T2-weighted axial lumbar spine magnetic resonance imaging. RESULTS: Facet joints were more sagittally and coronally oriented at the upper and lower lumbar levels, respectively. FJT was more obvious at lower lumbar levels. The FJT/FJO ratio was higher at upper lumbar levels. Patients with sagittally oriented facet joints at the L3-L4 and L4-L5 levels had fattier erector spinae and psoas muscles at the L4-L5 level. Patients with increased FJT at upper lumbar levels had fattier erector spinae and multifidus at lower lumbar levels. Patients with increased FJT at the L4-L5 level had less fatty infiltration in the erector spinae and psoas at the L2-L3 and L5-S1 levels, respectively. CONCLUSIONS: Sagittally oriented facet joints at lower lumbar levels could be associated with fattier erector spinae and psoas muscles at lower lumbar levels. The erector spinae at upper lumbar levels and psoas at lower lumbar levels might have become more active to compensate the FJT-induced instability at lower lumbar levels.

The anatomical location of cystic pseudotumors and muscle atrophy in metal-on-metal resurfacing hip arthroplasty is related to the surgical approach used for implantation. A subgroup analyses of a randomized controlled trial.

BACKGROUND: Pseudotumors and muscle atrophy have been associated with metal-on-metal (MoM) resurfacing hip arthroplasty (RHA). We aimed to investigate the influence of the anterolateral (AntLat) and the posterior (Post) surgical approach on the location, grade and prevalence of pseudotumors and muscle atrophy in MoM RHA. PATIENTS AND METHODS: Forty-nine patients were randomized to MoM RHA by the AntLat (n = 25) or the Post (n = 24) approach at Aarhus University Hospital. Patients underwent metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) scans for investigation of location, grade and prevalence of pseudotumors and muscle atrophy. Plain radiographs, metal-ions concentrations and clinical outcome scores were evaluated to compare outcomes of the surgical approaches. RESULTS: MRI-detected pseudotumors were seen in 7 of 18 patients (39%) in the AntLat group and in 12 of 22 patients (55%) in the Post group (p = 0.33). Pseudotumors were mainly located anterolaterally to the hip joint in the AntLat group and postero-lateral to the hip joint in the Post group. Higher grades of muscle atrophy of the caudal part of the gluteus medius and minimus (p < 0.004) were seen in the AntLat group, and higher grades of muscle atrophy of the small external rotators were seen in the Post group (p < 0.001). The AntLat group had higher anteversion angles of mean 15.3° (range 6.1-7.5) versus mean 11.5° (range 4.9-22.5) in the Post group (p = 0.02). Metal-ion concentrations and clinical outcome scores were similar between groups (p > 0.08). CONCLUSION: Muscle atrophy and pseudotumor location after MoM RHA follow the surgical approach used for implantation. This knowledge may help differentiate between "normal postoperative appearance" and "MoM disease."

At mid- to long-term follow-up after proximal hamstring tendon avulsion; there was greater fatty infiltration, muscle atrophy and strength deficit in the hamstring muscles of the injured leg than in the uninjured leg.

BACKGROUND: Proximal hamstring tendon avulsions (PHAs) may be treated nonoperatively or operatively. Little is known about the result of the injury, and its treatment, on the quality and function of the hamstring muscle after healing and rehabilitation. We hypothesized that the injured leg would have greater fatty infiltration and atrophy than the uninjured leg at follow-up and that these findings would correlate to muscle weakness. METHODS: In a cross-sectional cohort study, 48 patients treated for PHA, either operatively or nonoperatively, were re-examined 2-11 years post-treatment. We measured muscle strength with isokinetic strength tests, and muscle volume and fatty infiltration with MRI. Primary outcomes were hamstring muscle quality, quantified by outlining the cross-sectional area slice-by-slice, and the degree of fatty infiltration estimated using the Goutallier grading method. Secondary outcome was concentric isokinetic hamstring muscle strength measured using BioDex at 60°/sec and tendon attachment assessed on MRI. Comparisons with the outcomes of the uninjured leg were made. RESULTS: The total hamstring muscle volume was on average reduced by 9% (SD ± 11%, p < 0.001) compared to that of the uninjured leg. Fatty infiltration was significantly more severe in the injured hamstrings than in the uninjured hamstrings (p < 0.001). This was also true when only analyzing operatively treated patients. The reduction in muscle volume and increase in fatty infiltration correlated significantly (r = 0.357, p = 0.013), and there was also a statistically significant correlation with muscle atrophy and reduction in isokinetic strength (r = 494, p < 0.001). CONCLUSION: PHA injuries result in fatty infiltration and muscle atrophy and the muscle quality impairment correlates with residual muscle weakness.

Histological, radiological and clinical analysis of the supraspinatus tendon and muscle in rotator cuff tears.

BACKGROUND: Macroscopic alterations of the affected rotator cuff (RC) are undoubtedly linked to microscopic changes, but they may underestimate the actual degree of the disease. Moreover, it remains unclear whether preoperative structural RC changes may alter clinical outcomes. METHODS: Supraspinatus tendon and muscle samples were collected from 47 patients undergoing RC surgery. Tendons were evaluated histologically according to the Bonar score; fatty infiltration and muscle atrophy were quantified using a software for biomedical image analysis (ImageJ) in percentage of area affected in the observed muscle section. Preoperative shoulder ROM and pain were evaluated. Radiological muscle atrophy was evaluated with the Tangent Sign and Occupation Ratio; fatty infiltration was assessed according to the Goutallier classification. Correlations between histological, radiological and clinical outcomes were assessed. Statistics were performed using the Spearman correlation coefficient. Intraobserver and interobserver agreement was calculated. RESULTS: Histopathologic fatty infiltration (r = 0.007, p = 0.962), muscle atrophy (r = 0.003, p = 0.984) and the total Bonar score (r = 0.157, p = 0.292) were not correlated to preoperative shoulder pain. Muscle atrophy showed a significant but weak negative correlation with the preoperative movement of abduction (r = -0.344, p = 0.018). A significant but weak positive correlation was found between muscle atrophy and the total Bonar score (r = 0.352, p = 0.015). No correlation between histological and radiological evaluation was found for both fatty infiltration (r = 0.099, p = 0.510) and muscle atrophy (Tangent Sign: r = -0.223, p = 0.131; Occupation Ratio: r = -0.148, p = 0.319). Our histological evaluation showed a modal value of 3 (out of 3) for fatty infiltration and an equal modal value of 2 and 3 (out of 3) for muscle atrophy. In contrast, the modal value of the Goutallier score was 1 (out of 4) and 28 patients out of 47 showed a negative Tangent sign. At histology, intraobserver agreement ranged from 0.59 to 0.81 and interobserver agreement from 0.57 to 0.64. On the MRI intraobserver agreement ranged from 0.57 to 0.71 and interobserver agreement ranged from 0.53 to 0.65. CONCLUSIONS: Microscopic muscle atrophy appeared to negatively correlate with the movement of abduction leading to functional impairment. Shoulder pain did not show any relationship with microscopic changes. Radiological evaluation of the supraspinatus muscle alterations seemed to underestimate the degree of the same abnormalities evaluated at histology.

Incidence of muscle wasting in the critically ill: a prospective observational cohort study.

Loss of muscle mass occurs rapidly during critical illness and negatively affects quality of life. The incidence of clinically significant muscle wasting in critically ill patients is unclear. This study aimed to assess the incidence of and identify predictors for clinically significant loss of muscle mass in this patient population. This was a single-center observational study. We used ultrasound to determine the rectus femoris cross-sectional area (RFcsa) on the first and seventh day of ICU stay. The primary outcome was the incidence of significant muscle wasting. We used a logistic regression model to determine significant predictors for muscle wasting. Ultrasound measurements were completed in 104 patients. Sixty-two of these patients (59.6%) showed ≥ 10% decreases in RFcsa. We did not identify any predictor for significant muscle wasting, however, age was of borderline significance (p = 0.0528). The 28-day mortality rate was higher in patients with significant wasting, but this difference was not statistically significant (30.6% versus 16.7%; p = 0.165). Clinically significant muscle wasting was frequent in our cohort of patients. Patient age was identified as a predictor of borderline significance for muscle wasting. The results could be used to plan future studies on this topic.Trial registration: ClinicalTrials.gov NCT03865095, date of registration: 06/03/2019.

Paraspinal muscles atrophy on both sides and at multiple levels after unilateral lumbar partial discectomy.

To identify the changes in cross-sectional areas (CSAs) and fatty infiltration of both sides of the paravertebral muscles and their associations with prognostic factors in patients who underwent unilateral lumbar discectomy. We retrospectively reviewed 27 patients who underwent magnetic resonance imaging before and after 1- or 2-level lumbar discectomy. The CSAs and functional cross-sectional areas of the paraspinal muscles were bilaterally measured from L1 to L2 to L5 to S1 based on T2-weighted axial images. These parameters were compared pre-and postoperatively. CSAs and functional cross-sectional areas decreased also in non-operative, non-surgical levels, not only in operated levels after discectomy. In the correlation analysis, the CSA of psoas major muscle at L1 to L2 was significantly decreased in patients with lower preoperative lordosis (r = 0.598, P = .040). The postoperative CSA of psoas major muscle at L4 to L5 was lower in those with the higher Pfirrmann grade (r = -0.590, P = .002); however, the CSA of quadratus lumborum muscle at L1 to L2 showed the opposite result (r = 0.526, P = .036). Similar results were also observed in the partial correlation adjusted for age and postoperative duration. Patients who underwent discectomy experienced overall paraspinal muscle atrophy in the lumbar region, including surgical and non-surgical sites. Such atrophic changes emphasized the need for core strengthening and lumbar rehabilitation from the early period after partial discectomy.