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PubMed2006

[The effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty].

OBJECTIVE: To study the effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty (TKA) demonstrated on autopsy specimens, as the guide for surgeons to choose the correct reference axis for rotational alignment of the femoral components and to reduce the patellofemoral joint complications. METHODS: Select 9 frozen fresh human cadaver knees without gross deformities or instabilities and mount specimens on a patellofemoral joint testing jig connected to a Model 8501 Instron machine (Instron Corporation, Canton, MA). The study simulated the action of squatting from the standing position with the foot firmly planted. Standard TKA was performed in each specimen by the same senior surgeon using Nexgen LPS total knee system (Zimmer Corporation, Warsaw Indiana). Alter rotational alignment of the femoral components referenced to the transepicondylar axis and the Whiteside's line respectively. Measure biomechanics of the patellofemoral joints using Fuji prescale film at 30 degrees , 60 degrees , 90 degrees , 120 degrees of knee flexion respectively. The digital values were obtained by the handheld pressure measurement systems (FPD-305E, FPD-306E) and Autocad software. RESULTS: The rotational alignment of the femoral components paralleled to the transepicondylar axis had the best results of the peak value of the patellofemoral contact pressure (P < 0.05). There were no statistically significant differences in patellofemoral contact area (P > 0.05). But the patellofemoral contact area had the close correlations to the angles of the knee flexion and the specimens. CONCLUSIONS: Rotational alignment of the femoral components has a great influence on the patellofemoral contact pressure in total knee arthroplasty. It is reliable for surgeons to choose the transepicondylar axis as the reference axis to rotate femoral components.

Adult↗

PubMed1990

Correlation methods for the centering, rotation, and alignment of functional brain images.

Simple methods are described using correlation analysis to rotate functional brain images to a standard vertical orientation, identify the antero-posterior centerline, and align multiple images from the same brain level. Image rotation and centering are performed by determining the angle of rotation and centerline coordinate that result in maximal left-right correlation. Testing of this method on sets of multiple images acquired simultaneously through different brain levels suggests that the optimal rotation can be determined within 1 degree and the centerline within 0.3 mm. Spatial alignment of two or more images from the same brain level of a single subject is accomplished by finding the translation and rotation that yield the highest correlation between the images. Testing of the alignment method on sets of simultaneously acquired images at multiple brain levels suggests that the optimal translation can be determined within 0.45-0.69 mm and the optimal rotation within 0.8 degrees. These methods are completely objective and can easily be automated.

Aged↗

PubMed1989

Effect of rotation on the axial alignment of the femur. Pitfalls in the use of femoral intramedullary guides in total knee arthroplasty.

Intramedullary alignment guides for total knee arthroplasty are currently routine instruments. However, in some cases, the intramedullary guide can be misleading because of unusual femoral bowing and the rotational position of the femur. To determine the effect of rotation, an intramedullary guide was inserted into seven normal adult anatomic specimen femurs that were then examined roentgenographically in known positions of internal and external rotation. A variation of 2.5 degrees was found between the positions of 20 degrees of internal rotation and 20 degrees of external rotation of the femur. Intramedullary instrumentation provides sufficient accuracy when the femur has a normal anatomic shape. However, when an excessive degree of femoral bowing is present, rotational attitudes can affect the roentgenographic measurements, and thus it is prudent to use the intramedullary and extramedullary alignment guides whenever the roentgenogram indicates an unusual angle of femoral resection.

Femur↗

PubMed1989

Roentgenographic changes in proximal femoral dimensions due to hip rotation.

Three human adult femurs were examined using anteroposterior (AP) roentgenograms in anatomical position and in 15 degrees, 30 degrees, and 45 degrees of internal and external rotation. Relatively small (15 degrees or less) amounts of femoral rotation can cause significant changes in proximal femoral dimensions on supine AP hip roentgenograms, and the magnitude of these changes increases with rotation. Fifteen degrees of rotation can change it by almost 3 mm. These changes are comparable to the medullary canal expansion of a normal adult femur over a five- to ten-year period. These changes in measured proximal femoral dimensions with rotation necessitate either an improved roentgenographic technique or precise rotational matching of standard supine roentgenograms to obtain accurate measurements of their changes over time.

Femur↗

PubMed1987

Rotational approaches to atherectomy and thrombectomy.

We have developed and tested a rotational, mechanical approach to arterial plaque removal (PTRA or Percutaneous Transluminal Rotational Atherectomy). An elliptical burr is rotated by a helical driveshaft at 150,000 rpm. The tip of the burr is embedded with small diamond chips, 30 micron in diameter. Plaque is thus abraded and particles of 2-5 micron in diameter are released downstream. Preliminary studies in a rabbit model of iliac atherosclerosis showed a reduction in percent diameter stenosis from more than 80% to less than 40%. Perforations are the current principal complication, occurring in 2 of the 13 rabbit arteries. A second rotational catheter system has been developed for removal of fresh thrombus (PRT-Percutaneous Rotational Thrombectomy). Low speed rotation (5000 rpm) of a non-cutting catheter promotes the selective winding of fibrin with subsequent lysis of thrombus. This was effective in 20 out of 21 total thrombotic occlusions in a canine model of fresh clot, with a single perforation early in the experiment.

Animals↗

PubMed1984

Off-vertical rotation produces conditioned taste aversion and suppressed drinking in mice.

The effects of off-vertical rotation upon the intake of tap water immediately after rotation, and upon conditioned taste aversion, were assessed in mice with the tilt of the rotation axis varying from 5 to 20 degrees from the earth-vertical. Conditioned taste aversion occurred in all mice that were rotated, but the intake of tap water was suppressed only in mice that were rotated at 15 or 20 degrees of tilt. The greater suppression of tap water intake and the stronger conditioned aversion in the mouse as the angle of tilt was increased in this experiment are consistent with predictions from similar experiments with human subjects where motion sickness develops more rapidly as the angle of tilt is increased. It was suggested that off-vertical rotation may be a useful procedure for insuring experimental control over vestibular stimulation in animal studies of motion sickness.

Animals↗

PubMed1995

[Comparison between T2*- and T2-weighted images in diagnosing rotator cuff tears].

This study was performed to determine the merits of T2*-weighted images in diagnosing rotator cuff tear, compared with T2-weighted images. T2-and T2*-weighted images were obtained in 10 asymptomatic volunteers and 94 patients with symptoms referable to the rotator cuff. The increased signal with full thickness of the rotator cuff was not shown on either T2- or T2*-weighted images in the volunteers. These findings on T2-weighted images and on T2*-weighted images were observed in 33 and 58 of 94 patients with symptoms, respectively. Every patient who showed these abnormal findings on T2-weighted images had the abnormal findings on T2*-weighted images. These findings on T2*-weighted images were wider than those on T2-weighted images in 20 of 33 patients. Surgical findings were available in 21 of 94 patients. Rotator cuff tears were surgically confirmed in 20 patients whose MR images showed increased signal lesions on both T2- and T2*-weighted images. On the other hand, one patient who did not have rotator cuff tear showed increased signal lesion with full thickness on T2*-weighted images, but not on T2-weighted images. We think increased signal lesions on T2-weighted images may strongly suggest rotator cuff tear, whereas those on T2*-weighted images are not specific.

Adolescent↗

PubMed1995

Effects of continuous lateral rotation therapy on pulmonary complications in liver transplant patients.

BACKGROUND: When liver transplant candidates and recipients suffer from pulmonary complications of immobility, the results can be life-threatening. Continuous lateral rotation therapy has been reported to decrease complications of immobility. OBJECTIVES: To determine whether continuous lateral rotation therapy decreases the duration of mechanical ventilation, intensive care unit length of stay, incidence or resolution of atelectasis, incidence or onset time of lower respiratory tract infection and pneumonia. METHODS: Sixty-nine subjects admitted to a liver transplant intensive care unit at a university teaching hospital were randomly assigned to continuous lateral rotation therapy or a stationary bed. All subjects were mechanically ventilated for 24 hours and had a Glasgow Coma Scale score of 11 or less upon admission to the study. Subjects were followed until out of bed, unable to rotate for 3 consecutive days, or transferred from the intensive care unit. Data and chest roentgenogram results were collected on admission and daily during the study. Sputum culture results were obtained if available as part of normal patient care. RESULTS: Incidence of lower respiratory tract infection was significantly lower and length of time to occurrence of lower respiratory tract infection was significantly longer in the continuous lateral rotation therapy group than in the stationary bed group. CONCLUSIONS: Although continuous lateral rotation therapy did not affect duration of mechanical ventilation, length of stay, or incidence of atelectasis, it was effective in decreasing the incidence of, and increasing onset time to, lower respiratory tract infection in the liver transplantation population.

Adolescent↗

PubMed1994

Rapid plasma reagin card test: evaluation of a hand-rotation procedure and stability of the RPR antigen.

Reported are the results of a comparative study of two procedures for the rapid plasma reagin (RPR) test for syphilis serology: in one approach a mechanical rotator was used and in the other, hand rotation was employed. Both procedures were performed on 327 sera. The agreement between both was 98.8%. Three sera that exhibited minimal reactivity (titre = 1) in the mechanical-rotation RPR were nonreactive in the hand-rotation RPR. RPR antigen was stored for 3 months at room temperature (mean, 21 degrees C) and 30 degrees C. There was no difference in the reactivity of 62 sera (50 positive, 12 negative) that were tested using either adversely stored antigens or antigen stored at 4 degrees C. In poorly equipped settings at the primary health care level, the hand-rotation RPR is a practical alternative to mechanical rotation. Also, the stability of the antigen under adverse storage conditions is an additional advantage of RPR for use in tropical areas.

Antigens, Bacterial↗

PubMed1993

Sensing and controlling rotational orientation in normal subjects and patients with loss of labyrinthine function.

The disability resulting from uni-or bilateral loss of vestibular function was assessed by exposing subjects, in darkness, to random rotational displacements on a motorized chair away from a "center" position and requiring them to rotate themselves back to center using a "joystick" control. Normal subjects were accurate within 10 to 15 percent over 180-degree rotations. Alabyrinthine subjects failed to sense their rotation to any useful extent. Subjects with unilateral loss of function as a result of surgery produced hypometric responses to ipsilateral rotation and large amplitude, but inaccurate responses to contralateral rotation. This pattern became more symmetric and normometric with adaptation to loss of function. The procedure promises to be a more useful measure of adaptation than assessing vestibulo-ocular reflexes.

Adult↗

PubMed1993

Determining the rotational alignment of the femoral component in total knee arthroplasty using the epicondylar axis.

The posterior condylar surfaces of the femur are routinely used as the reference for the rotational orientation of the femoral component during most primary total knee arthroplasties. The purpose of this investigation was to identify a clearly discernible, reproducible secondary anatomic axis useful for determining the rotational orientation of the femoral component when the posterior condylar surfaces cannot be used. Seventy-five embalmed anatomic specimen femurs were studied. A surgical epicondylar axis was defined as the line connecting the lateral epicondylar prominence and the medial sulcus of the medial epicondyle. The posterior condylar angle was measured as the angle between the posterior condylar surfaces and the surgical epicondylar axis. Measurement of the posterior condylar angle referenced from the surgical epicondylar axis yielded a mean posterior condylar angle of 3.5 degrees (+/- 1.2 degrees) of internal rotation for males and a mean posterior condylar angle of 0.3 degree (+/- 1.2 degrees) of internal rotation for females. Thus, rotational alignment of the femoral component can be accurately estimated using the posterior condylar angle. The posterior condylar angle, referenced from the surgical epicondylar axis, provides a visual rotational alignment check during primary arthroplasty and may improve alignment of the femoral component at revision.

Biometry↗

PubMed1996

Increased rotational mobility and extractability of band 3 from protein 4.2-deficient erythrocyte membranes: evidence of a role for protein 4.2 in strengthening the band 3-cytoskeleton linkage.

Band 3 (anion-exchange protein 1-[AE1]) is the major integral membrane protein of human erythrocytes and links the membrane to the underlying cytoskeleton via high-affinity binding to ankyrin. It is unclear whether other cytoskeletal proteins participate in strengthening the ankyrin-band 3 linkage, but a putative role for protein 4.2 (P4.2) has been proposed based on the increased osmotic fragility and spherocytic morphology of P4.2-deficient red blood cells (RBCs). The present study was designed to investigate the hypothesis that P4.2 has a direct role in strengthening the band 3-cytoskeleton linkage in human RBCs, by measuring independent features of this interaction in normal and P4.2-deficient RBCs. The features examined were the rotational mobility of band 3 assayed by time-resolved phosphorescence emission anisotropy (TPA), and the extractability of band 3 by octyl-beta-glucoside, the latter being a nonionic detergent that selectively extracts only band 3 that is not anchored to the cytoskeleton. We find that the amplitude of the most rapidly rotating population of band 3 (correlation time, approximately 30 to 60 microseconds) is increased 81% and 67% in P4.2-deficient ghosts (P4.2NIPPON and band 3MONTEFIORE, respectively) compared with control ghosts. The amplitude of the intermediate speed rotating population of band 3 (correlation time, approximately 200 to 500 microseconds) is increased 23% and 8% in P4.2-deficient ghosts (P4.2NIPPON and band 3MONTEFIORE, respectively) compared with control ghosts, at the expense of the slowly rotating component (correlation time, approximately 2,000 to 3,000 microseconds, amplitude decreased 43% and 39% in P4.2NIPPON and band 3MONTEFIORE, respectively) and immobile component (immobile on this experimental time scale; amplitude decreased 26% and 10% in P4.2NIPPON and band 3MONTEFIORE, respectively) of band 3. These results demonstrate that P4.2 deficiency partially removes band 3 rotational constraints, ie, it increases band 3 rotational mobility. The nonionic detergent octyl-beta-glucoside, which does not disturb band 3-cytoskeleton associations, ie, it extracts only band 3 that is not attached to the cytoskeleton, extracted 30% and 61% more band 3 from P4.2NIPPON and band 3MONTEFIORE ghost membranes, respectively, compared with control ghosts. The octyl-beta-glucoside ghost extracts from both P4.2-deficient phenotypes were enriched in band 3 oligomeric species (tetramers, higher-order oligomers, and aggregates) compared with controls. Since band 3 oligomers selectively associate with the cytoskeleton, these results are consistent with a weakened band 3-cytoskeleton linkage in P4.2-deficient RBC membranes. P4.2 deficiency does not affect band 3 anion transport activity, since uptake of radiolabeled sulfate was similar for control and P4.2-deficient RBCs. Thus, we propose that P4.2 directly participates in strengthening the band 3-cytoskeleton linkage.

Anion Exchange Protein 1, Erythrocyte↗

PubMed1997

Effect of femoral component rotation and patellar design on patellar forces.

A force transducer attached to the patella was used to measure patellar contact forces after total knee arthroplasty for neutral femoral component position and for 10 degrees internal and external femoral component rotations. Knees were cycled continuously under load from 10 degrees to 110 degrees flexion. Two designs of knee replacement with differing degrees of intrinsic tibiofemoral constraint were studied. Additionally, contact forces for a dome shaped patella and a modified dome shaped patella (a patellar component with a central projection surrounded by a peripheral flat region) were compared. When using the design with relatively high intrinsic tibiofemoral constraint, there were no significant changes in patellar contact forces after axial rotation of the femoral component. When using the design with relatively low intrinsic tibiofemoral constraint and averaging over the range of flexion angles tested, the mediolateral component of the patellar contact force increased approximately 17% after 10 degrees internal rotation compared with neutral rotation, and the normal component of the patellar contact force decreased approximately 8% after a 10 degrees external rotation compared with 10 degrees internal rotation of the femoral component. The inferosuperior component of the patellar shear force, when using the modified dome shaped patellar component, was significantly lower than for the dome shaped patella.

Aged↗

PubMed1998

The effect of rotational head and neck movements on the afferent cerebral blood flow.

OBJECTIVE: To determine the effect of lateral rotational head and neck movements on the afferent cerebral blood flow in healthy adult humans so as to increase our knowledge of the relationship between arterial resistance and blood flow in the afferent cerebral arteries and in the arterial segments of the circle of Willis. DESIGN: Prospective, experimental study. SETTING: Department of Radiology and Department of Functional Anatomy, Utrecht University, Utrecht, The Netherlands. SUBJECTS: Nine healthy adult male human volunteers aged between 24 and 52 years participated in this study with informed consent. MAIN OUTCOME MEASURES: The changes in the afferent cerebral blood flow between the neutral (face to the front) and the rotated head positions (turn to the right and turn to the left). The relationship between the changes in the afferent cerebral blood flow and the angle of the head rotation. RESULTS: There were no significant differences between the changes in the afferent cerebral blood flow of the neutral and of the rotated head positions (p = 0.930 and p = 0.508 for the right and left head turns respectively). The correlation coefficients between the changes in the afferent cerebral blood flow and the angle of head rotation which ranged between 44.5 degrees and 72 degrees for the right turn and between 45 degrees and 72 degrees for the left turn were also not statistically significant (p = 0.191 for the right turn and p = 0.570 for the left turn). CONCLUSION: The most likely explanation for these observations was that the changes in resistance in the afferent cerebral arteries of these healthy volunteers were too small to produce significant blood flow changes. Therefore, we conclude that normal physiological lateral rotational head and neck movements do not produce any significant blood flow changes in the afferent cerebral arteries of healthy adults.

Adult↗

PubMed2026

Impact of smoking on structural failure after arthroscopic rotator cuff repair: a systematic review and meta-analysis.

BACKGROUND: Rotator cuff tears cause significant shoulder pain and functional limitation. Arthroscopic rotator cuff repair improves symptoms, yet structural failure rates remain substantial. Smoking may impair tendon-to-bone healing, but clinical studies report mixed findings due to heterogeneous methodology. Therefore, a systematic synthesis of imaging-confirmed outcomes is needed to clarify the association between smoking and structural failure after arthroscopic rotator cuff repair. METHODS: This review followed PRISMA 2020 and was registered in PROSPERO (CRD420251246197). PubMed, Embase, Scopus, Web of Science, and the Cochrane Library were searched from inception to 12 December 2025. Comparative clinical studies of adults undergoing arthroscopic rotator cuff repair that reported imaging-confirmed structural integrity (magnetic resonance imaging or ultrasonography) at ≥6 months were included. Two reviewers independently screened studies, extracted data, and assessed quality using the Newcastle-Ottawa Scale. The primary outcome (structural failure) was pooled as risk ratios using a random-effects model with the restricted maximum likelihood estimator and Hartung-Knapp adjustment. Secondary continuous outcomes were synthesized using Bayesian random-effects models; subgroup, sensitivity, and meta-regression analyses explored heterogeneity. RESULTS: Ten cohort studies (1,683 shoulders) were included. Smoking was associated with a higher risk of imaging-confirmed structural failure (risk ratio 1.53; 95% confidence interval 1.13-2.08; P = .011) with low heterogeneity (I2 = 24.7%). Subgroup and sensitivity analyses supported robustness, with no evidence of effect modification by region, follow-up duration, tear size, or smoking definition. Meta-regression showed no significant influence of age, smoking prevalence, or diabetes prevalence on the pooled effect. Secondary outcomes (3 studies) suggested slightly lower postoperative American Shoulder and Elbow Surgeons scores among smokers, while visual analog scale pain scores and forward flexion showed no clear between-group differences. No publication-bias signals were detected for the primary outcome. CONCLUSION: Smoking is associated with a higher risk of imaging-confirmed structural failure after arthroscopic rotator cuff repair. Functional outcomes were broadly similar between groups, with only a small, likely clinically negligible reduction in American Shoulder and Elbow Surgeons scores among smokers. These findings support careful smoking history assessment and perioperative risk modification, including smoking cessation strategies.

Humans↗

PubMed1998

Glenohumeral joint: internal and external rotation range of motion in javelin throwers.

OBJECTIVE: To assess differences in glenohumeral joint rotatory range of movement in javelin throwers between the throwing and non-throwing arm. METHOD: A universal 360 degrees goniometer was used to assess glenohumeral joint external and internal rotation range in 90 degrees of shoulder abduction in a group of ten senior international javelin throwers. RESULTS: Both arms had significantly greater degrees of external than internal rotation (p < 0.01), and the throwing arm had significantly greater range of external rotation than the non-throwing arm (p < 0.01). CONCLUSIONS: The presence of an excessive range of external rotation in the throwing shoulder has the potential to increase eccentric load on the rotator cuff muscles and strain on the passive restraints of the glenohumeral joint. Both of these factors have been implicated in the pathological processes leading to injury in the overhead throwing athlete.

Analysis of Variance↗

PubMed2025

The effects of N-acetylcysteine and adipose-derived stem cells on tendon healing in chronic rotator cuff tears: a rabbit model study.

BACKGROUND: Rotator cuff tears are associated with significant morbidity, and retear rates after surgical repair remain high, largely due to chronic degenerative changes such as muscle atrophy and fatty infiltration. This study aims to evaluate the effects of locally injected adipose tissue-derived stem cells and orally administered N-acetylcysteine, individually and in combination, on tendon healing in a rabbit model of chronic rotator cuff rupture. METHODS: Thirty-two male New Zealand white rabbits were used as models of chronic rotator cuff tear, surgically established by detaching the supraspinatus tendon and delaying repair to create a chronic defect. The rabbits were divided into four groups: Group A (control, saline-treated), Group B (N-acetylcysteine-treated), Group C (adipose tissue-derived stem cells-treated), and Group D (combined adipose tissue-derived stem cells and N-acetylcysteine-treated). Chronic rotator cuff tear repairs were conducted after six weeks. Histological, immunohistochemical, and biomechanical assessments were performed 12 weeks post-repair. Key outcomes included collagen organization, fatty infiltration, type I collagen expression, and tensile strength. RESULTS: Histopathological analysis revealed significantly improved collagen fiber alignment, reduced fatty infiltration, and decreased inflammation in Groups C and D compared to Groups A and B (p < 0.001). Immunohistochemical analysis revealed higher Type I collagen reactivity in Groups C and D, with Group D exhibiting the highest reactivity (p < 0.001). Biomechanical testing confirmed significantly increased load to failure in Groups C and D, with Group D achieving the highest values (p < 0.001). CONCLUSIONS: Adipose tissue-derived stem cells and N-acetylcysteine independently promote tendon healing, with adipose tissue-derived stem cells showing superior effects on collagen organization and fatty infiltration reduction. Combined treatment with adipose tissue-derived stem cells and N-acetylcysteine demonstrated synergistic effects, resulting in optimal tendon regeneration and strength. These findings support the potential of adipose tissue-derived stem cells and N-acetylcysteine as complementary therapies for chronic rotator cuff injuries. Further research is warranted to explore their mechanisms of action and clinical applications.

Animals↗

PubMed2005

Limitations of isokinetic testing to determine shoulder strength after rotator cuff repair.

Some investigators have reported incomplete data when using isokinetic testing as a means of analyzing shoulder strength after rotator cuff repair. An explanation provided has been that the subjects could not reach the speed at which the machine was set. The purpose of this study was to determine if strength data could be generated for all motions being tested by using not only the one or two speeds employed by others, but three speeds across the spectrum of those available. Inclusion criteria were a minimum of two years since surgery with a normal contralateral shoulder. All eligible subjects had isokinetic testing of the non-operated shoulder followed by the operated shoulder, in flexion, abduction and external rotation, tested at 60 degrees, 120 degrees and 180 degrees per second. Fourteen patients were eligible and tested. Isokinetic data showed deficiencies in strength in the operated shoulder compared to the opposite side for abduction, external rotation and flexion of 14%, 27% and 20% respectively. In 10/123 (8%) of the tests, the patients could not reach the preset velocity to yield valid data. One patient could not place and maintain the operated arm in the test position of 90 degrees of shoulder abduction. There was a significant deficiency in abduction at only one of three speeds. This study confirms that isokinetic testing is a powerful tool that lends itself well to producing objective data on shoulder strength after rotator cuff repair, but it also has the limitation that some patients cannot reach the preset velocity for some motions, or place and maintain the operated arm in the test position for the movements being tested. Therefore, to optimize the chances of obtaining isokinetic data for all movements after rotator cuff repair, we suggest using speeds for all motions and consideration of scapular, frontal and sagittal planes for testing.

Adult↗