Degrees Of Internal Rotation Research Articles

Statistical thermodynamics of internal rotation in a hindering potential of mean force obtained from computer simulations.

A method of statistical estimation is applied to the problem of one-dimensional internal rotation in a hindering potential of mean force. The hindering potential, which may have a completely general shape, is expanded in a Fourier series, the coefficients of which are estimated by fitting an appropriate statistical-mechanical distribution to the random variable of internal rotation angle. The function of reduced moment of inertia of an internal rotation is averaged over the thermodynamic ensemble of atomic configurations of the molecule obtained in stochastic simulations. When quantum effects are not important, an accurate estimate of the absolute internal rotation entropy of a molecule with a single rotatable bond is obtained. When there is more than one rotatable bond, the "marginal" statistical-mechanical properties corresponding to a given internal rotational degree of freedom are reduced. The method is illustrated using Monte Carlo simulations of two public health relevant halocarbon molecules, each having a single internal-rotation degree of freedom, and a molecular dynamics simulation of an immunologically relevant polypeptide, in which several dihedral angles are analyzed.

Rotational constraint in posterior-stabilized total knee prostheses.

Rotational stresses from box-post impingement have been implicated in the loosening of posterior-stabilized total knee prostheses. A bench model was constructed to assess the forces generated by tibiofemoral rotation. Rotational torque under load was measured in two different posteriorstabilized total knee prostheses using an axial-torsion load cell at 0 degrees, 20 degrees, and 40 degrees flexion over 20 degrees internal and external rotation. The Sigma posterior-stabilized prosthesis generated little torque through 5 degrees internal and external rotation. An increase in torque then occurred because of box-post impingement, generating peak torques of 17 to 18 N-m at 12 degrees to 14 degrees rotation. The bench model produced the same deformation of the polyethylene post as seen on retrieved specimens. The Scorpio posterior-stabilized prosthesis had a relatively continuous rise in generated torque from tibiofemoral conformity. Box-post impingement did not occur resulting in 32% lower torque between 12 degrees and 14 degrees rotation. Peak rotational torques of 15 to 16 N-m were reached at 19 degrees to 20 degrees rotation. Tibiofemoral conformity is the primary source of rotational constraint. Box-post impingement can be a source of additional rotational constraint. Depending on specific design features, small changes in relative tibiofemoral component rotation can more than double the generated torque. Axial rotation of the knee in vivo can generate substantial torque. Relative tibiofemoral rotational position is an important factor influencing component function and fixation.

Is there evidence that performing joint manipulation under local anesthetic block might be more effective than continuing a program of joint mobilization, stretching, and mobility exercises in a woman with recalcitrant adhesive capsulitis of the shoulder?

The purpose of “Evidence in Practice” is to illustrate the literature search process to obtain evidence that can guide clinical decision making. This article is not a case report. The examination, evaluation, and intervention sections are purposely abbreviated. A 45-year-old woman was referred by her health care provider to our outpatient physical therapy department with a 6-month history of pain and stiffness in her left shoulder and inability to perform her normal daily activities (eg, bathing, grooming, cleaning the house, and cooking). She particularly reported difficulty with overhead tasks such as washing her hair. She reported a gradual onset of left shoulder pain and stiffness without any known precipitating incident. Previous physical therapy intervention over a period of 6 weeks—consisting of passive joint mobilization, range-of-motion (ROM) exercises, and muscle stretching—had not been effective in improving her function or diminishing her pain. In addition, this patient had received local anti-inflammatory steroid injections with no reported improvements in mobility, function, or pain. Because the injections did not produce improvements in these areas, she declined a referral for another trial of injections. The initial examination of the patient revealed generally decreased ROM in the left shoulder. Range of motion was assessed with the patient in the supine position using procedures described by Norkin and White.1 We found that both passive and active ROM were limited to 115 degrees of flexion, 50 degrees of abduction, 25 degrees of internal rotation, and 5 degrees of external rotation. Previous studies have found the reliability of measuring ROM with a standard goniometer in this fashion to range from moderate to high, particularly for intrarater reliability.2–5 Based on the work of Cyriax,6 we measured end feels for all shoulder motions and found them to be capsular. The inter-rater reliability of end-feel measurements has …

The relationship between the strength of supination of the forearm and rotation of the shoulder.

In children with obstetric brachial plexus palsy (OBPP) who develop an internal rotation deformity of the shoulder, release of subscapularis improves the range of external rotation of the shoulder and the strength of supination of the forearm. We studied the strength of supination in 35 healthy adult volunteers at 45 degrees of both internal and external rotation. The mean and maximum torques were greater in external than internal rotation by 8.7% and 7.5%, respectively. This was highly significant (p < 0.0001). The increased strength of supination in external rotation is probably because the maximum power of biceps, particularly the long head, may be exerted in this position. In children the difference may be even greater due to anatomical differences causing the dramatic increases in the strength of supination after surgery for OBPP. In adults our findings suggest that the supination exercises which are undertaken after injury or surgery to the forearm or wrist should be performed in external rotation.

Distal Tibia Metaphyseal Fractures Treated by Percutaneous Plate Osteosynthesis

Twenty-one patients with fractures of the distal tibial metaphysis, some with minimal displacement in the ankle, were treated by percutaneous plate osteosynthesis with a narrow limited contact-dynamic compression plate. Using the classification by the Arbeitsgemeinschaft für Osteosynthesefragen and Orthopaedic Trauma Association, 17 fractures had no articular involvement, whereas four included intraarticular extension. At final followup (mean, 20 months), all the fractures healed without second procedures and the mean union time was 15.2 weeks. One patient had malalignment of the limb with 10 degrees internal rotation, but there were no angular deformities greater than 5 degrees or any shortening greater than 1 cm. All patients had excellent or satisfactory ankle function. There were no infections or any soft tissue compromise. Percutaneous plate osteosynthesis is a safe and worthwhile method of managing such fractures, which avoids some of the complications associated with conventional open plating methods.

Application of the stochastic tunneling method to high throughput database screening

The stochastic tunneling technique is applied to screen a database of chemical compounds to the active site of dihydrofolate reductase for lead candidates in the receptor–ligand docking problem. Using an atomistic force field we consider the ligand’s internal rotational degrees of freedom. It is shown that the natural ligand (methotrexate) scores best among 10 000 randomly chosen compounds. We analyze the top scoring compounds to identify hot-spots of the receptor. We mutate the amino acids that are responsible for the hot-spots of the receptor and verify that its specificity is lost upon modification.

Does acetic acid iontophoresis accelerate the resorption of calcium deposits in calcific tendinitis of the shoulder?

The purpose of “Evidence in Practice” is to illustrate the literature search process to obtain evidence to guide clinical decision making. This article is not a case report. The examination, evaluation, and intervention sections are purposely abbreviated. A 48-year-old man, who was otherwise in good health, developed pain and a “clicking” sensation in his right shoulder during movement. The patient, who was referred to me by his physician, stated that this problem began approximately 2 months ago and has been getting steadily worse ever since. The patient is an avid skier and tennis player; however, he did not recall any serious direct trauma to the shoulder. Shoulder passive range of motion (ROM), measured using standard goniometric techniques as discussed by Riddle et al,1 was 0 to 170 degrees for flexion, 0 to 165 degrees for abduction, 0 to 70 degrees for internal rotation, and 0 to 75 degrees for external rotation. Manual muscle testing did not reveal any major strength deficits in the shoulder musculature, with the primary muscle groups graded between 4+ and 5 on scale of 0 to 5. Active humeral abduction, however, resulted in pain, especially near the midpoint of shoulder abduction. Radiographs that had been ordered by the physician showed a calcium deposit in the tendon of the right supraspinatus muscle. This deposit was approximately 175 mm2 in area, had well-defined borders, and was uniformly dense throughout the lesion. This patient, therefore, appeared to have calcific tendinitis of the right supraspinatus muscle. Based on my evaluation of these and other examination data, my diagnosis for this patient was “Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Localized Inflammation” (Practice Pattern 4E, Guide to Physical Therapist Practice [Guide]2). Consistent with the Guide, I decided to implement an intervention program …

Inversion injury biomechanics in functional ankle instability: a cadaver study of simulated gait.

The purpose of this study was to test pathogenetic models for the "unprovoked" ankle inversion injuries seen in functional ankle unstable subjects. The consequence of spatial mal-alignment of the ankle/foot complex on the risk of producing an ankle inversion torque at heel-strike and during swing-phase follow through was analyzed in cadaver simulations. Heel-strike was simulated using a 5 degrees of freedom rig in a material testing machine. A set-up capable of accelerating lower limb specimens towards a support surface simulated swing-phase follow through. Joint excursions were monitored with flexible wire goniometers. The unloaded ankle/foot complex was placed in increasing positions of talar and subtalar joint excursions. The consequences of these settings on the behavior of the ankle/foot complex at heel-strike and when the lateral part of the foot "caught" the ground during swing-phase follow through were monitored. An inversion torque at heel-strike was first seen when the unloaded foot was set in positions exceeding 30 degrees of inversion combined with full plantar flexion and 10 degrees of internal tibial rotation. A collision between the lateral border of a 20 degrees inverted, but otherwise neutral ankle/foot complex and the ground surface during swing-phase follow through forced the foot into the full limit of inversion, plantar flexion and internal tibial rotation measurable in this set-up. Clinical consequence: The study showed that the foot/ankle complex exhibits a high degree of intrinsic stability at heel-strike. The foot will thus stabilize itself and move into normal eversion at the beginning of the stance-phase even though it is set to the ground in a substantial degree of mal-alignment. In contrast, the swing-phase collision model provides a link that can connect the small deficits in inversion angle awareness measured in chronic functional ankle unstable subjects with an increased risk in this group of sustaining ankle inversion injuries.

A combined nuclear dynamics and electronic study of the coupling between the internal rotation of the methyl group and the intramolecular proton transfer in 5-methyltropolone

In this work we have theoretically studied the splittings experimentally observed in 5-methyl tropolone in the first excited singlet state, S1. Tropolone shows a vibrational level splitting due to delocalization of the wave function over the symmetric potential energy double well in the proton-transfer coordinate. This splitting dramatically decreases when asymmetry is introduced. However, a noticeable splitting is observed in 5-methyltropolone internal rotational levels indicating a coupling between methyl internal rotational and proton-transfer degrees of freedom. We have developed a reduced-dimensionality model for the potential energy surface (PES), which maintains the main characteristics of the molecule and that can be fitted to electronic structure calculations. For this PES we have calculated stationary wave functions using a full quantum method. We have performed test calculations using different energy barrier heights in order to observe the splitting behavior for this kind of molecules. In order to fit our PES to the real system surface we have also performed an extensive set of ab initio calculations in the S1 state using different methods. Finally we present a discussion about such electronic calculations, showing the present difficulties to obtain excited state potential energy surfaces with great accuracy beyond the Franck–Condon vertical excitation region.

Total knee arthroplasty for arthritis of the knee with extra-articular deformity.

Simultaneous corrective osteotomy of angular deformity and total knee arthroplasty has been considered the treatment of choice for patients with arthritis of the knee associated with ipsilateral extra-articular deformity. However, this procedure is technically demanding, and the functional outcome of the total knee arthroplasty may be jeopardized if the osteotomy fails. This retrospective study was performed to evaluate the clinical results of total knee arthroplasty combined with intra-articular bone resection, without osteotomy, in patients with extra-articular deformity and arthritis of the knee. Fifteen patients with arthritis of the knee and extra-articular deformity underwent total knee arthroplasty with bone resection and soft-tissue balancing. All deformities had resulted from fracture malunion. There were ten uniplanar, three biplanar, and two triplanar deformities. The deformity was in the tibia in eight patients and in the femur in seven. The average angle of the femoral deformities was 15.1 degrees in the coronal plane and 8.1 degrees in the sagittal plane. Two femora had a rotational deformity, consisting of 20 degrees of internal rotation in one and 10 degrees of external rotation in the other. The average angle of the tibial deformities was 19 degrees in the coronal plane. The duration of follow-up averaged thirty-eight months. The average Knee Society knee score improved from 22.3 points preoperatively to 91.7 points at the time of the last follow-up, and the average Knee Society function score improved from 28.0 points preoperatively to 87.3 points at the time of the last follow-up. The average arc of knee motion improved from 77.7 degrees preoperatively to 103.7 degrees postoperatively. The average mechanical axis of the knee improved from 22.7 degrees of varus preoperatively to 0.3 degrees of varus at the time of the last follow-up. Two patients had an unsatisfactory clinical result, which was not related to the total knee arthroplasty. There were no complications such as infection, ligament instability, or component loosening. Total knee arthroplasty in conjunction with intra-articular bone resection is an effective procedure for patients with arthritis of the knee and extra-articular varus deformity of <20 degrees in the femur or 30 degrees in the tibia in the coronal plane.

Gender Differences in Patellofemoral Joint Biomechanics

Patellofemoral pain is associated with patellar malalignment and quadriceps weakness which are seen more commonly in women. The objective of the current study was to determine the effects of gender, vastus medialis strength, and tibial rotation on patellofemoral joint biomechanics. Twelve fresh-frozen knees from cadavers were tested using a custom knee jig. Anatomic multiplane loading of the extensor mechanism was used with varying vastus medialis loads. Patellofemoral contact area and pressure were measured using pressure sensitive film at knee flexion angles of 0 degrees, 30 degrees, 60 degrees, and 90 degrees with the tibia in neutral and 15 degrees internal and external tibial rotation. Patellofemoral joint contact areas in specimens from men were larger at knee flexion angles greater than 30 degrees. A significant increase in mean patellofemoral contact pressures was seen for specimens from women when compared with specimens from men at 0 degrees and 30 degrees knee flexion. The knees from women also showed a greater change in contact pressures to varying vastus medialis load at knee flexion angles of 0 degrees, 30 degrees, and 60 degrees. The results of the current study indicate that there are gender differences in patellofemoral contact areas and pressures. These differences may help explain the increased incidence of patellofemoral disorders in women.

Varus and Valgus Flexion Laxity of Total Knee Alignment Methods in Loaded Cadaveric Knees

Both total knee alignment methods, the anatomic and classic, seek to achieve stability in flexion and extension. However, posterior femoral condyle referencing (anatomic alignment) combined with perpendicular tibial resection (classic alignment) results in a 3 degree relative internal rotation of the femoral component with lateral joint opening. The current cadaver study investigated the influence of total knee alignment methods and femoral component malrotation (3 degrees and 6 degrees internal and external malrotation) on femorotibial laxity. Varus and valgus excursion tests were done at 0 degrees, 30 degrees, 60 degrees, and 90 degrees knee flexion under vertical loading conditions of 150 N. None of the alignments produced increased laxity in extension. The largest laxity was found on the varus test at 60 degrees flexion with the femoral component at 6 degrees internal rotation. A 3 degree internal rotation of the femoral component showed increased varus laxity only for the combined alignment method. This finding shows that the femoral component position of the combined alignment method is a 3 degree relative internal malrotation and that an additional internal malrotation may compromise varus stability. Posterior femoral condyle referencing did not provide proper femoral component rotation. A ligament tensor may be helpful in determining femoral component rotation after soft tissue release in extension is performed.

肩外旋動作に伴う表層筋群とけん板の筋活動様相

The goal of our studies is to examine the mechanism of the muscle output of the shoulder joint. In this paper we compared and quantified electromyographic muscle activities and the onset order of the rotator cuff and shoulder superficial muscles in relation to the change in concentric torque generated by performing shoulder external rotation.Twenty-four healthy male subjects (mean age 23.3) without any history of shoulder injury participated in the experiments. A Cybex 770 dynamometer was used to control the load and the angle of motion; the range of loads was 0-18 Nm, the range of motion was 75-0 degrees of internal rotation, and the angular velocity of the movements was fixed at 15 deg/sec. Electromyographs (EMGs) were recorded using surface electrodes placed on the shoulder superficial muscles and intramuscular wire electrodes from the rotator cuff. The raw EMG signals for each load were separated into five equal parts (each covering 15 degrees), which were then separately rectified and integrated. The integrated EMG data, which was normalized against data for maximum voluntary contraction, was compared for each load and each angle condition.The results of this experiment clearly showed that the supraspinatus (SSP), middle deltoid (MD), and middle trapezius (MT), as well as infraspinatus (ISP), teres minor (TM), and posterior deltoid (PD) muscles took part in external rotational movements. The EMG-onsets of the rotator cuff were generally faster, and their muscle activities were greater, than in the superficial muscles. For each muscle, however, the degree of participation was markedly dependent on the load and angle of motion.The EMG-onset of the ISP was the fastest, and the muscle activity of the ISP was the highest of all muscles, irrespective of load or angle of motion. It is thus certain that the ISP plays an important role as both a stabilizer and a mover during external rotational movement. At low loads, the TM demonstrated a pattern of muscle activity similar to that of the ISP, but it was notable that muscle activity did not increase for loads greater than 30-40% MVC. On the other hand, the muscle activity of the SSP was lower than that of the TM in the area approaching full internal rotation and at low loads. As the load increased, however, muscle activity of the SSP became higher than that of the TM. The TM and the SSP, therefore, may have different functional roles depending on the situation; both muscles may contribute to external rotational movements as the supporting mover.The muscle activity of the MD was higher than that of the PD in the area approaching full internal rotation. Clearly, not only the PD but the MD also takes part in external rotational movements, depending on the angle of motion. The EMG-on-set of the MT was faster, and the muscle activity of the MT at low loads was higher, than seen in other superficial muscles. Moreover, the activity of the MT increased with increasing load and degree of external rotation. These results suggest that the MT assists the mover muscles by anchoring the scapula at low loads but adducting it at high loads and in the area of external rotation.

Effect of arm elevation and rotation on the strain in the repaired rotator cuff tendon. A cadaveric study.

In 14 cadaveric shoulders, a rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force with the arm in adduction. Strain on the repaired tendon was measured at 0 degrees, 15 degrees, 30 degrees, and 45 degrees of elevation in the sagittal, scapular, and coronal planes and from 60 degrees of internal rotation to 60 degrees of external rotation. The strain in all of the planes decreased significantly with the arm elevated more than 30 degrees. With 30 degrees of elevation in the scapular and coronal planes, the strain increased in internal rotation and decreased in external rotation. In all of the positions measured, the strain in the sagittal plane was significantly greater than in the other planes. We concluded that more than 30 degrees of elevation in the coronal or scapular plane and rotation ranging from 0 degrees to 60 degrees of external rotation compose the safe range of motion after repair of the rotator cuff.

Component rotation and anterior knee pain after total knee arthroplasty.

All patients undergoing cruciate-retaining primary total knee arthroplasty for degenerative osteoarthritis at one center were studied prospectively. Clinical and radiographic followup was obtained at a minimum 5 years in 102 knees in 73 patients. Patients were asked specifically about the presence of the pain in the anterior aspect of the knee in the vicinity of the patella and rated the severity of the pain on a visual analog scale. Significant anterior knee pain rating at least 3 of 10 on the visual analog scale was present in 16 knees (13 patients). Eleven patients with 14 symptomatic knees agreed to undergo computed tomography scanning to accurately determine the rotation of the tibial and femoral components. The epicondylar axis and tibial tubercle were used as references using a previously validated technique. A control group of 11 asymptomatic patients (14 knees), matched for age, gender, and length of followup also underwent computed tomography scanning. All patients in both groups had normal axial alignment. There was a highly significant difference in tibial component rotation between the two groups with the patients with anterior knee pain averaging 6.2 degrees internal rotation compared with 0.4 degrees external rotation in the control group. There also was a significant difference in combined component rotation with the patients with anterior knee pain averaging 4.7 degrees internal rotation compared with 2.6 degrees external rotation in the control group. There was no significant difference in the degree of radiographic patellar tilt or patellar subluxation between the two groups. Patients with combined component internal rotation were more than five times as likely to experience anterior knee pain after total knee arthroplasty compared with those with combined component external rotation. Component malrotation is a significant factor in the development of anterior knee pain after total knee arthroplasty.

Optimizing femoral component rotation in total knee arthroplasty.

Femoral component rotation is important in total knee arthroplasty to optimize patellofemoral and tibiofemoral kinematics. More recently, the epicondylar axis has been cited as the definitive landmark for femoral component rotation. However, there are few studies to support the validity of this rotational landmark and its effect on the patellofemoral and tibiofemoral articulations. In the current study, a total knee arthroplasty was done in 11 knees from cadavers. The knees were tested with various femoral component rotations from 5 degrees internal rotation to 5 degrees external rotation referenced to the epicondylar axis and to the posterior femoral condyles. Each knee acted as its own internal control. The knees were actively ranged from 0 degrees to 100 degrees by a force on the quadriceps tendon in an Oxford knee simulator. Three-dimensional kinematics of all three components were measured whereas a multiaxial transducer imbedded in the patella measured patellofemoral forces. Femoral component rotation parallel to the epicondylar axis resulted in the most normal patellar tracking and minimized patellofemoral shear forces early in flexion. This optimal rotation also minimized tibiofemoral wear motions. These beneficial effects of femoral rotation were less reproducibly related to the posterior condyles. Rotating the femoral component either internal or external to the epicondylar axis worsened knee function by increasing tibiofemoral wear motion and significantly worsening patellar tracking with increased shear forces early in flexion. Based on the current study, the femoral component should be rotationally aligned parallel to the epicondylar axis to avoid patellofemoral and tibiofemoral complications.

Modular component exchange for treatment of recurrent dislocation of a total hip replacement in selected patients.

Exchange of modular components is a treatment option for the correction of recurrent dislocation of a total hip replacement. In this study, we reviewed our experience with this technique in order to define patient selection criteria and to report the outcome of treatment. Of 2935 hips treated with primary porous-coated total hip arthroplasty, fourteen (in fourteen patients) that met certain preoperative and intraoperative criteria were treated with modular component exchange because of recurrent hip instability. The primary arthroplasties in these fourteen patients had been performed through a posterior approach. At the revisions, we removed any sources of osseous or soft-tissue impingement that contributed to dislocation. Acceptable stability at the completion of component exchange was defined as stability in maximum flexion, in full extension with external rotation, and in at least 45 degrees of internal rotation with the hip in 90 degrees of flexion and maximum adduction. One patient was lost to follow-up. At a mean of 5.8 years (range, 2.8 to 11.8 years) after the revision, ten of the remaining thirteen patients had not had a dislocation. Of the three patients in whom the hip dislocated after the modular component exchange, only one had recurrent dislocation; thus, recurrent dislocation was eliminated in twelve of thirteen patients. In selected cases, modular component exchange for the treatment of recurrent hip dislocation has a success rate comparable with that of more extensive operations. This method should be considered because it avoids the morbidity associated with revision of well-fixed components. However, to ensure the appropriateness of this surgical option, each patient must be thoroughly evaluated to identify all factors that contribute to instability and adequate intraoperative stability must be achieved.

Comparison of Shoulder Positions at MR Arthrography: Change of Labroligamentous Complex Shape and Diagnosis of Labral Tears

purpose: To compare the neutral, internal, and external rotation positions of the glenohumeral joint during magnetic resonance (MR) arthrography performed to assess changes in the shape of the labroligamentous complex (LLC) and in the labral tear. Materials and Methods: MR arthrography of the shoulder was retrospectively evaluated in 36 patients aged 14-66 (mean, 40) years. Fourteen cases were confirmed by arthroscopic surgery (7 SLAP lesions, 2 Bankart lesions, 1 both SLAP and Bankart lesions). Axial fat-suppressed T1-weighted spin-echo images were acquired with each shoulder in the neutral position, and with internal and external rotations. In each position, we measured the angle of rotation between the perpendicular line on the glenoid fossa and the long axis of the humeral head, analyzing the relationship between the rotational angle and changes in the shape of the LLC at each internal and external rotation, relative to the neutral position. In addition, labral tears in 14 arthroscopically confirmed joints were evaluated in each position. Results: Mean angles of rotation relative to the neutral position were 44.1 and 45.3 degrees in internal and external rotation, respectively. Changes in the anterior LLC occurred in 25 and 24 cases of internal and external rotation, respectively. There was a significantly meaningful relationship between rotational angle and change in the shape of the anterior LLC during external rotation, and when this change was noticed, the rotational angle was wider (p

Thumb reconstruction with a wraparound free flap according to the level of amputation.

We surgically treated 37 thumbs amputated distal or proximal to the metacarpophalangeal (MCP) joint using a wraparound free flap from the great toe for the reconstruction. We studied the functional results of the procedure according to the level of amputation and the fixation angle of the iliac bone block. The cases were divided into 2 groups: group 1, which comprised 25 cases with the level of amputation distal to the MCP joint, and group 2, which comprised 12 cases with the level of amputation at or proximal to the MCP joint. Opposition of the reconstructed thumb to the other fingers was completely possible in all cases in group 1. In group 2 opposition was completely possible in 6 cases in which the iliac bone block was fixated into the position of 30 degrees flexion and 45 degrees internal rotation; in the remaining 6 cases, in which the graft was fixated into the position of 30 degrees flexion and 30 degrees internal rotation, complete opposition of the reconstructed thumb to the ring and little fingers was not possible. We found that amputation of the thumb proximal to the MCP joint is not an absolute contraindication for the wraparound free flap reconstruction. We recommend fixating the iliac bone block into 30 degrees flexion and 45 degrees internal rotation to obtain better functional outcome in cases with amputation at or proximal to the MCP joint.

Constraint dynamics for quantum Monte Carlo calculations

We describe how to apply classical constraint dynamics to problems in diffusion Monte Carlo. We apply the method to rigid and nonrigid water molecules with an internal rotational degree of freedom. The method is applicable to a wide variety of problems.