Introduction. This paper describes the kinetic and electromyographic contribution of principal muscles around the shoulder of a cohort of patients with reverse total shoulder arthroplasty (RTSA). Surgeries for RTSA significantly increased in the last five years. Initially developed to treat patients with cuff tear arthropathy and pseudoparalysis, wider indications for RTSA were described (massive non repairable rotator cuff tears, complex 4-parts fractures). Since Grammont's theory in 1985, the precise biomechanics of the RTSA has not yet been demonstrated in vivo. Clinical results of patients with RSTA are still unpredictable and vary one from another. Methods. We conducted an observational prospective cohort study comparing 9 patients with RTSA (surgery more than 6 months and rehabilitation process achieved) and 8 controls with normal shoulder function adjusted for age, sex and dominance. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p<0,05). Results. ROM is limited in the RSTA group (flexion 128,5 vs 152,6, p=0,04; abduction 150 vs 166, p=0,02; neutral ext rot 28.3 vs 75.6, p<0,01; 90° ext rot 26,43 vs 70,63, p<0,01, int rot 27.5 vs 49.4, p=0,01). Anterior and middle deltoid shows less muscular activation in RTSA than in controls, sustaining the deltoid potentiation described by Grammont. Posterior deltoid shows decreased activity in external rotation movements in RTSA. Upper trapezius is the main activator in all directions with an early and constant activity in RTSA (p<0,01). Latissimus dorsi demonstrates increased muscular activity in internal rotation with RTSA (p<0,01). Discussion. The sequence of muscular activation in RTSA is different than in normal shoulder. Grammont's theory is confirmed with this study. The significant contribution of both the trapezius and latissimus dorsi has never been described until today. New rehabilitation protocols targeted on those muscle groups could demonstrate better and more homogenous clinical results

An electromyographic investigation of patients with subluxation of the patella has been carried out on the parts of the extensor apparatus which actively contribute to the alignment of the patella, both before and after the operation to correct this disorder. The electromyographic pictures have revealed a sharp fall in the activity of the vastus medialis, with full recovery to normal values after a corrective operation. Even if the aligning function of the patella is altered by a variety of factors, the present study confirms the importance of the vastus medialis in the pathogenesis of malalignment of the extensor mechanism

We compared the quantitative electromyographic activity of the elbow flexors during four exercises (forced inspiration, forced expiration, trunk flexion and attempted elbow flexion), following intercostal nerve transfer to the musculocutaneous nerve in 32 patients who had sustained root avulsion brachial plexus injuries. Quantitative electromyographic evaluation of the mean and maximum amplitude was repeated three times for each exercise. We found that mean and maximum elbow flexor activity was highest during trunk flexion, followed by attempted elbow flexion, forced inspiration and finally forced expiration. The difference between each group was significant (p < 0.001), with the exception of the difference between trunk flexion and attempted elbow flexion. Consequently, we recommend trunk flexion exercises to aid rehabilitation following intercostal nerve transfer

We present the electromyographic (EMG) results ten years after open decompression of the median nerve at the wrist and compare them with the clinical and functional outcomes as judged by Levine’s Questionnaire. This retrospective study evaluated 115 patients who had undergone carpal tunnel decompression at a mean of 10.47 years (9.24 to 11.36) previously. A positive EMG diagnosis was found in 77 patients (67%), including those who were asymptomatic at ten years. It is necessary to include both clinical and functional results as well as electromyographic testing in the long-term evaluation of patients who have undergone carpal tunnel decompression particularly in those in whom revision surgery is being considered. In doubtful cases or when there are differing outcomes, self-administered scales such as Levine’s Questionnaire should prevail over EMG results when deciding on the need for revision surgery

Surgeries for reverse total shoulder arthroplasty (RTSA) significantly increased in the last ten years. Initially developed to treat patients with cuff tear arthropathy (CTA) and pseudoparalysis, wider indications for RTSA were described, especially complex proximal humerus fractures. We previously demonstrated in patients with CTA a different sequence of muscular activation than in normal shoulder, with a decrease in deltoid activation, a significant increase of upper trapezius activation and slight utility of the latissimus dorsi. There is no biomechanical study describing the muscular activity in patients with RTSA for fractures. The aim of this work is to describe the in vivo action of RTSA in patients with complex fractures of the proximal humerus. We conducted an observational prospective cohort study comparing 9 patients with RTSA for complex humerus fracture (surgery more than 6 months, healed tuberosities and rehabilitation process achieved) and 10 controls with normal shoulder function. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p < 0,05). The overall range of motion with RTSA is very good, but lower than the control group: flexion 155.6 ± 10 vs 172.2 ± 13.9, p<0.05, external rotation at 90° 55.6 ± 25 vs 85.6 ± 8.8, p<0,05, internal rotation at 90° 37.8 ± 15.6 vs 52.2 ± 12, p<0,05. The three heads of the deltoid are more stressed during flexion and abduction in the RTSA group (p. The increased use of the 3 deltoid chiefs does not support the hypothesis proposed by Grammont when the RTSA is performed for a complex proximal humerus fracture. This can be explained by the reduced dispalcement of the rotation center of the shoulder in these patients compared to those with CTA. These patients also didn't present shoulder stiffness before the fracture. The maximal muscle activity of the trapezius in flexion and of the latissimus dorsi in flexion and abduction had not been described to date. These new findings will help develop better targeted rehabilitation programs. In addition, the significant role of the latissimus dorsi must question the risks of its transfer (L'Episcopo procedure) to compensate for external rotation deficits

Introduction. Latissimus dorsi transfer is a procedure used in massive irreparable posterosuperior rotator cuff tears, in young patient with severe pain and significant functional impairment. The purpose of this retrospective study was to evaluate its clinical, radiological and electromyographic results. Methods. Forteen massive irreparable posterosuperior rotator cuff tears were performed with latissimus dorsi transfer between 2000 and 2008, and were reviewed at an average follow-up of 56 months and minimum of 19 months. Five transfers were primary reconstructions, and nine were revision surgeries. Patients’ mean age was 52.7 years. Clinical outcomes were measured by the Constant score, pain level, active range of motion, and strength. Osteoarthritis and acromiohumeral distance were measured on standardized radiographs. Ultrasound examination evaluate the integrity of the tendon. Axial images in CT-scan looked for muscle atrophy of latissimus dorsi in comparison with the controlateral. Electromyographic activity was measured during active flexion, abduction, adduction and rotations. Results. Twelve patients were satisfied. At the last follow-up, the average pain level according to a 100 mm visual analog scale was 31. The mean age and gender-matched Constant and Murley score improved from 34 to 60 % (p=0.003), forward elevation from 89° to 132° (p=0.006), abduction from 92° to 104°, external rotation from 12° to 24° (p=0.015). Mean abduction and external rotation strength were measured at 2.5 kg. Osteoarthritis progressed, and mean acromio-humeral distance has a significant decrease from 7.5 mm to 4.4 mm (p=0.003). Ultrasound examination showed twelve transferred tendons healed to the greater tuberosity. CT-scan showed a small atrophy of the transferred muscle, with a measurement of the cross-sectional area of the muscle belly at the inferior angle of the scapula at 1405 mm2, versus 1644 mm2 for the controlateral (p=0.06). Electromyographic analysis demonstrated a significant higher electric activity on the operative side during abduction and external rotation, and significant lower activity during adduction and internal rotation in comparison with the nonoperative side. Conclusions. Latissimus dorsi transfer allows for significant pain relief and function improvement in irreparable posterosuperior rotator cuff tears at young patients. Its electric activity increase in abduction and external rotation shows that the transferred muscle can integrate a new function and act like an active muscle transfer, in addition to an interposition or tenodesis effect. However we didn't find any depression of the humeral head or strength improvement

Aim: To compare the effects of botulinum toxin injection with and without electromyographic (EMG) assistance for the treatment of spastic muscles. Methods: In a prospective comparative study, botulinum toxin was injected intramuscularly into 17 patients with spasticity due to CNS damage (CP, SCI, head injury, stroke). All patients were evaluated using the modified Ashworth scale and the score was 2–4. In 9/17 patients, group A (53%), the injection was given with EMG assistance, while in 8/17 patients, group B (47%), without, always from the same injectionist. The follow-up period ranged from 4 to 24 months. Results: Average spasticity decreased in all injected muscles and new scores were 1–2 grades less according the modified Ashworth scale. No complications or side effects were noted. The average reduction of spasticity reached 1.66 (SD 0.5) in group A and 1.25 (SD 0.46) in group B. The average reduction of spasticity was statistically more pronounced in group A (p< 0.001). Conclusions: The effectiveness of botulinum toxin injection for the treatment of muscle spasticity in patients with CNS damage increases when used with EMG assistance and this is attributed to the appropriateness of points for injection

Electromyographic and clinical studies were performed on patients undergoing total hip replacement by the modified direct lateral (29 hips), the direct lateral (29 hips) and the posterior approaches (21 hips). Assessments were made three months after operation. The Trendelenburg test was positive (Grade II) in eight cases operated upon by the direct lateral route, but in only one of each of the other two groups. Denervation occurred in only five of the 28 hips with abductor weakness without statistical difference between the groups. In the modified direct lateral group, radiological evidence of union of the trochanteric sliver was associated with significantly better abductor function than in those with malunion or non-union

To compare the effects of botulinum toxin injection with and without electromyographic (EMG) assistance for the treatment of spastic muscles. In a prospective comparative study, botulinum toxin was injected intramuscularly into 17 patients with spasticity due to CNS damage (CP, SCI, head injury, stroke). All patients were evaluated using the modified Ashworth scale and the score was 2–4. In 9/17 patients, group A (53%), the injection was given with EMG assistance, while in 8/17 patients, group B (47%), without, always from the same injectionist. The follow-up period ranged from 4 to 24 months. Average spasticity decreased in all injected muscles and new scores were 1–2 grades less according the modified Ashworth scale. No complications or side effects were noted. The average reduction of spasticity reached 1.66 (SD 0.5) in group A and 1.25 (SD 0.46) in group B. The average reduction of spasticity was statistically more pronounced in group A (p< 0.001). The effectiveness of botulinum toxin injection for the treatment of muscle spasticity in patients with CNS damage increases when used with EMG assistance and this is attributed to the appropriateness of points for injection

Purpose: It is known from the literature that gripping, which is commonly used in various work-related, sport-related, and daily activities, activates both wrist extensors and flexors. Pain aggravation occurs during grip due to over-exertion of the extensor muscle group in lateral epicondylitis and grip strength is reduced. Of grip strength studies, few studies have simultaneously investigated muscular response using electromyography as a method of monitoring muscular fatigue or muscular activity of forearm muscles. The fatigability and activity of wrist antagonistic muscles in patients with lateral epicondylitis has not been previously investigated. Methods: 16 tennis elbow patients (Tennis Elbow Group) and 16 healthy volunteers (Control Group) were participated in this study. In both groups, local muscular fatigue and muscular activity were measured for 3 forearm muscles contributing to the wrist extension and 2 muscles contributing to the wrist flexion using EMG and during gripping at 50% maximum voluntary contraction (MVC). Fatigability and activity of muscles then were compared between control and tennis elbow groups. Results: Grip strength was significantly lower in tennis elbow group than that in control group (p < 0.05). Median frequency (MDF) and root mean square (RMS) of electromyographic signals were used as parameters to measure muscular fatigue and muscular activity, respectively. Further analysis showed no significant difference in the fatigability of forearm muscles between two groups. The activity of Extensor Carpi Radialis (ECR) showed statistically significant reduction in tennis elbow group compared to the control group (p < 0.05). Conclusion: This is the first study to simultaneously investigate the fatigability and activity of the forearm antagonistic muscle groups in patients with lateral epi-condylitis. The fact that ECR showed similar level of muscular fatigue to other muscles despite decreased muscular activity may indicate of higher fatigability of this muscle in tennis elbow. Furethermore, decreased muscular activity of ECR may be a part of mechanism to protect the muscle from further injury in tennis elbow patients

Background:. It is not well known how different external loads influence shoulder kinematics and muscle activity in patients with shoulder prostheses. Study objective: define shoulder kinematics and determine the scapulothoracic contribution to total shoulder motion, in combination with shoulder muscle activity and the degree of co-contraction, of patients with total (TSA) and reverse shoulder arthroplasties (RSA) and healthy individuals during rehabilitation exercises using different loading conditions. Methods:. Shoulder motions (anteflexion and elevation in the scapular plane) of 17 patients (20 shoulders) with a TSA, 8 patients (9 shoulders) with a RSA and 15 healthy subjects were measured using anelectromagnetic tracking device. A force transducer recorded force signals during loaded conditions (without external load, 1 kg and elastic resistance). Electromyographic (EMG) activity of the deltoid (anterior, middle, posterior parts), latissimus dorsi, pectoralis major (clavicular and sternal parts), teres major and serratus anterior was recorded and the degree of co-contraction calculated. Results:. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects and during loaded versus unloaded tasks. Glenohumeral elevation angles during anteflexion were significantly higher in the TSA than in the RSA group. Higher activity of the middle and posterior deltoid was found in the TSA group compared to healthy subjects and for the pectoralis major (sternal part) in the RSA group compared to TSA and healthy subjects. For all muscles, except the serratus anterior, activity was lower for unloaded tasks compared to 1 kg dumbbell and elastic band resistance. No main effect of group or load for degree of co-contraction was detected in both exercises. Conclusions:. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant, but differed both compared to healthy subjects. Scapular kinematics of patients with shoulder arthroplasties were influenced by implementation of external loads, however, not by the type of load. There were no differences in muscle activity and degree of co-contraction between patient groups

Background: Progression of fatty infiltration of the suscapularis muscle subsequent to total shoulder arthroplasty is frequent and may be an underestimated problem. The approach with osteotomy of the lesser tuberosity led to consistent bone to bone healing with neither retraction nor overtensioning of the musculotendinous unit. However, in a previous study, fatty infiltration of the subscapular muscle had progressed at least by one stage in 45% of the patients’ shoulders. We hypothesized that anterior approach to the shoulder joint with release of the subscapularis muscle would lead to a direct or indirect subclinical damage of the subscapular nerve and would be an explanation for the progression of fatty infiltration of the muscle. Methods: Nine Shoulders in eight consecutive patients had received a total shoulder arthroplasty using an anterior approach with osteotomy of the lesser tuberosity. The mean age at time of operation was 67 years. Patients were followed clinically including the Constant score and a detailed neurological examination, as well as radiographically with pre–and postoperative MRI’s, CT’s and standard radiographs at 6–and 12 months thereafter. Neurophysiological assessment was performed using a new pre–intra–and postoperative electromyographic technique for the subscapular muscle. Fibrillation and sharp waves as spontaneuous activities of the motor unit potentials (MUP) indicated direct signs of denervation. Incomplete interference patterns (IP’s) indicated an incomplete innervation pattern as an indirect sign of denervation. Results: After a one year follow up, 89% of the patients were very satisfied or satisfied with the result. The relative Constant Score improved from an average of 50 percent preoperatively to an average of 96 percent postoperatively (p=0,008). That corresponds to a postoperative subjective Shoulder value of 89 percent. From preoperative to 6–and 12-months postoperative, the average degree of fatty infiltration of the subscapular muscle progressed in an almost significant extent (0.6, 1.1, and 1.6 respectively; p=0.056). Intra–and postoperatively, there were neither fibrillations and sharp waves of the MUP’s as direct signs, nor incomplete (IP’s) of the motor unit of the subscapular nerve as indirect signs of denervation. Conclusion: Total Shoulder Arthroplasties perfomed by an anterior approach using an osteotomy of the lesser tuberosity yields good results with a high satisfaction rate. Comparable to our previous study, there are signs of progression of fatty infiltration of the subscapularis muscle within the first year subsequent to total shoulder arthroplasty. However, there were no signs of direct or indirect subclinical damage of the subscapular nerve during total shoulder arthroplasty

Recently a great amount of research has been conducted into fatigability of paraspinal muscles in relation to Lower Back Pain (LBP). Additionally relationships have been observed between a general level of “fitness” and LBP. This research project aimed to evaluate the influence of aerobic fitness and health on lower back muscle function as measured by Electromyographic (EMG) spectral parameters. Participants undertake a series of psychometric tests, anthropometric data collection, EMG spectral analysis of the paraspinal muscles at lumbar and thoracic regions, and an aerobic fitness test. The EMG test involves a 30-sec isometric pull against a load normalised for weight. The spectral half-width, initial median frequency and median frequency slope are calculated. Participants are given biofeedback and exercise advice. Participants in this study were of above average fitness level compared to normative data. Other anthropometric data were similar to previous work conducted within this department. Preliminary regression analysis results have revealed no relationships between aerobic fitness level and EMG parameters, a finding that is counter to current beliefs on LBP and fitness, however it was observed that age did significantly influence lumbar spectral variable values (p = .002). A similar psychological profile was observed for all fitness levels

The EMG activities of the gastrocnemius and soleus muscle of five normal subjects were measured during non-weight bearing, heel and normal walking either with or without using a walking boot. The boot was set to plantigrade initially, then equinus by either adding a wedge inside or by adjusting the hinge. Results showed that heel walking has significantly lower EMG activities than normal walking while non-weight-bearing walking has the lowest activity. The wedge has no effect on decreasing the calf muscle EMG activity. Locking the boot into equinus produced a paradoxically higher EMG activity and a rather awkward gait.

We prospectively studied the use of intercostal EMG monitoring as an indicator of the accuracy of the placement of pedicle screws in the thoracic spine.

We investigated 95 thoracic pedicles in 17 patients. Before insertion of the screw, the surgeon recorded his assessment of the integrity of the pedicle track. We then stimulated the track using a K-wire pedicle probe connected to a constant current stimulator. A compound muscle action potential (CMAP) was recorded from the appropriate intercostal or abdominal muscles. Postoperative CT was performed to establish the position of the screw. The stimulus intensity required to evoke a muscle response was correlated with the position of the screw on the CT scan.

There were eight unrecognised breaches of the pedicle. Using 7.0 mA as a threshold, the sensitivity of EMG was 0.50 in detecting a breached pedicle and the specificity was 0.83.

Thoracic pedicle screws were accurately placed in more than 90% of patients. EMG monitoring did not significantly improve the reliability of placement of the screw.

We performed electrophysiological studies on both legs of 52 children, aged from 3 months to 15 years, with idiopathic club foot. In only nine (17%) was no abnormality found. Isolated peroneal nerve damage was seen in 14 (27%). Abnormality of both peroneal and posterior tibial nerves was found in five (10%). Four patients (8%) had evidence of isolated spinal-cord dysfunction, whereas combined spinal-cord and peripheral-nerve lesions were seen in 14 (27%). Six patients (11%) had variable neurogenic electrophysiological patterns. In 13 patients in whom the studies were repeated neither progression nor improvement of the electrophysiological parameters was observed. Pathological electrophysiological findings were found in 66% of conservatively-treated patients. In the 43 patients treated surgically, all 16 with fair and poor results had pathological electrophysiological findings and 12 required further operations. Multiplicity of the pathological findings was related to the severity of the deformity of the foot; normal studies represent a good prognostic sign. Electrophysiological studies are useful in idiopathic club foot with residual deformities after conservative or operative treatment. Our findings support the theory that muscle imbalance is an aetiological factor in idiopathic club foot.

The role of muscle function in the aetiology of recurrent dislocation of the patella has been examined. Eleven of the 12 patients we studied had joint hypermobility. Muscle biopsies from eight of nine patients treated by surgery had a predominance of abnormal Type 2C fibres, and three of six patients whose quadriceps muscles were studied by electromyography also had abnormal results. Our preliminary findings suggest that there may be a primary muscular defect in many cases of recurrent dislocation of the patella.

This pilot study assesses level of agreement between surface and fine wire electromyography (EMG), in order to establish if surface is as reliable as fine wire in the diagnosis and treatment of abnormal muscle patterning in the shoulder. 18 subjects (11 female, mean 36 years) with unstable shoulders were recruited after written consent and ethical approval. Anthropometric information and mean skinfold size for triceps, subscapular, biceps and suprailiac sites were obtained. Triple stud self adhesive surface electrodes (“Triode” – Thermo Scientific) were placed over Pectoralis Major (PM), Latissimus Dorsi (LD), Anterior Deltoid (AD) and Infraspinatus (IS) at standardised locations. A ‘Medi-Link’ dual channel surface EMG (Electro Medical Supplies) displayed a rectified smoothed signal. Patients performed five identical uniplanar standard movements (flexion, abduction, external rotation, extension and cross body adduction). After a rest period, a dual needle technique for fine wire insertion was used displaying a raw EMG signal on a ‘Sapphire II’ four channel EMG unit. An experienced examiner in each technique reported if muscle activation patterns differed from agreed normal during any movement and were blinded to the other test results. Sensitivity, specificity and kappa values for level of agreement between methods were calculated for each muscle according to the method of Altman. 15 patients were successfully tested. Sensitivity, specificity and kappa values between techniques for each muscles were PM (57%, 50%, 0.07), LD (38%, 85%, 0.22), AD (0%, 76%, −0.19) and IS (85%, 75%, 0.6). Only IS demonstrated high sensitivity and specificity and a moderate level of agreement between the two techniques. There was no correlation between skinfold size and agreement levels. Surface did not agree with wire analysis for PM, LD and AD, although IS did show moderate agreement. Subcutaneous fat did not appear to affect correlation.

Introduction

Shoulder motion results from a complex interaction between the interconnected segments of the shoulder girdle. Coordination is necessary for normal shoulder function and is achieved by synchronous and coordinated muscle activity. During rotational movements, the humeral head translates on the glenoid fossa in the anterior-posterior plane. Tension developed by the rotator cuff muscles compresses the humeral head into the glenoid fossa. This acts to limit the degree of humeral head translation and establishes a stable GH fulcrum about which the arm can be moved. Previous studies have been limited by the use of contrived movement protocols and muscular coordination has not been previously considered with regard to shoulder rotation movements. This study reports the activation profile and coordination of 13 muscles and 4 muscle groups during a dynamic rotational movement task based on activities of daily living.

Purpose of this study is to compare the indications and the clinical results of the surgical treatment of CTS in relation to the EMS studies.

Material & Method: From September 1998 until the end of 2002, at Lefkadas hospital, 153 patients [189 hands] were treated with surgical decompression for C.T.S. Ninety operations were executed on the right wrist, fifty-five on the left & twenty-two bilateral. 121 patients were females & 32 males.

The classic microsurgical technique was executed at 149 patients. (A three-centimeter longitudinal incision, which was never extended beyond the distal crease of wrist. At twenty-one patients, the double-incision technique was performed [a small transverse incision at the wrist’s distal crease, & a short longitudinal incision five centimeters away from the distal crease of wrist). While in 20 patients we decompressed the C.T. from just one small transverse incision at the wrist’s distal crease.

It was possible to follow up, with clinical findings and repeated EMS, only sixty of them.

All operations were executed under local anesthesia and loupes were always used.

The cases that we operated on are of medium and of advanced severity of chronic carpal tunnel syndrome, while, according to the neurologist, at least five cases were acute.

The first follow-up was done on the 2nd or 3rd postoperative day. The patients’ positive assertions that numbness – tingling and nocturnal pain that used to jolt them awake at night were cured were of a great importance.

After the sixth postoperative month, a new EMG study was performed, at the patient’s convenience. A questionnaire was given to the patient to answer.

Results: Except for four patients, two of them didn’t improve their symptoms after the operation, while the rest two after the fourth postoperative week relapsed (relapse confirmed via electromyography), all other patients had either full recovery or significant improvement. The above-mentioned results are confirmed by clinical history, physical examination, study of the answers of the questionnaire that have been given to them, and at the end of the EMG study that always have been performed (showing normal or improved status in comparison to the pre-operative state).

Conclusion: Clinical postoperative findings match electromyography studies (at least in the first postoperative year).