Biomedical subjects

M Kronberg

Publications and source records attributed to M Kronberg.

12 recordsLinked to original sources

PubMed1992

The effect of shoulder muscle training in patients with recurrent shoulder dislocations.

Thirty-three shoulders in 29 patients with recurrent shoulder dislocations, of both traumatic and nontraumatic type, have been studied. The patients suffered from muscle weakness, and had also a hypotrophy of the supra- and infraspinatus muscles. A special training program using an isokinetic pulley-weight apparatus, for muscle strength, coordination and endurance training of the rotator-cuff muscles and the deltoid were given all patients. Shoulder flexors, internal and external rotator muscles were trained three times a week, during a period of 8 weeks. At follow-up one year after completion of the specific training program all shoulders except five were improved. Five shoulders had remaining instability. Four of these patients had generalized joint laxity and a much decreased humeral head retroversion, and were later on stabilized with a rotational osteotomy of the proximal humerus. One of the shoulders with remaining instability was of traumatic type with normal skeletal anatomy. This patient was later on stabilized with a Putti-Platt procedure. We conclude that most of the patients were relieved from pain, and had decrease or cessation of their dislocations. Factors indicating a less good result of training were an abnormal skeletal anatomy, and/or a multidirectional type of instability.

Adult↗

PubMed1992

Should the glenoid be replaced in shoulder arthroplasty with an unconstrained Dana or St. Georg prosthesis?

Twenty-six patients, 11 with rheumatoid arthritis and 15 with osteoarthritis, have been operated on with an unconstrained total shoulder arthroplasty. Mean follow-up was 47 months. Three prostheses have been extracted. All patients stated that they had pain relief after surgery. At three year follow-up all except one had developed radiolucent zones around the glenoid component. No zones were observed around the humeral component. In shoulders with preserved glenoid surface replacement of only the humeral head might provide better long-term results than a total shoulder arthroplasty.

Adult↗

PubMed1992

Clinical features and walking ability in the early postoperative period after treatment of trochanteric hip fractures. Results with special reference to fracture type and surgical treatment.

The purpose of this study was to analyze the functional outcome during the early postoperative period (six weeks) in patients with trochanteric fractures. A consecutive series of 149 patients were randomized to treatment with either the DHS or Ender operative technique. 120 patients were available at review six weeks after surgery. Groups were comparable with respect to age (mean 77 years), sex ratio (73% women), type of fracture (59% and 55% unstable), experience level of the surgeon, prefracture health condition and ambulatory status. During follow-up eight patients died and there were 19 complications of neurologic and cardiovascular types equally spread among the two groups. All four infections were found in the DHS group. Orthopaedic hospital stay averaged 19 days and more patients in the Ender group could return to their previous home at time of discharge. At the six week visit 14% in the Ender group compared to 33% in the DHS group had not recovered functional walking distance (less than 15 m). All patients in the Ender group managed to walk, but 11% of the patients in the DHS group could not walk. Walking ability was most impaired for unstable fractures. It is concluded that the Ender technique will involve less operative trauma (shorter operations with less blood loss) and in the early postoperative period it can provide better conditions for walking and less need for further hospitalization than the DHS technique.

Aged↗

PubMed1991

Proximal humeral osteotomy to correct the anatomy in patients with recurrent shoulder dislocations.

Surgical treatment of patients with traumatic shoulder dislocations is usually successful, but soft-tissue surgery in patients with nontraumatic shoulder dislocation often fails to stabilize the joint. Previous studies have shown that decreased humeral head retroversion might be one cause of anterior shoulder instability. Eleven patients with anterior recurrent dislocations, five traumatic and six nontraumatic, and all with a small humeral head retroversion angle, have been operated on using a proximal humerus osteotomy to correct the abnormal anatomy. After surgery, the humeral head retroversion was normalized to a mean angle of 34 degrees. All shoulders became stable. External rotation increased 7 degrees on the average, and internal rotation decreased 10 degrees on the average. One year after surgery, shoulder function was excellent in all operated shoulders.

Adult↗

PubMed1991

Differences in shoulder muscle activity between patients with generalized joint laxity and normal controls.

The aim of the present study was to analyze shoulder muscle activity in patients with generalized joint laxity and shoulder instability and to compare it with muscle activity recorded in healthy subjects from an earlier study. Electromyographic (EMG) activity was recorded from eight shoulder muscles in six patients using surface and intramuscular fine-wire electrodes. Recordings were made from the subscapularis, supraspinatus, infraspinatus, pectoralis major (sternoclavicular part), the anterior, middle, and posterior parts of the deltoid, and the latissimus dorsi. The EMG signal was low-pass filtered, full-wave rectified, and time-average. Normalization of the EMG allowed interindividual and intraindividual comparisons. During abduction and flexion, muscle activity in the anterior and middle parts of the deltoid was significantly decreased in the patients, and during internal rotation activity in the subscapularis was increased. As in healthy subjects, patients showed simultaneous activity in both those muscles producing the movement and in the antagonistic muscles. The altered muscle activity observed in patients with generalized joint laxity provides (1) a basis for understanding the mechanism of their shoulder instability and (2) the rationale for a physical training program for these patients.

Adult↗

PubMed1990

Electromyogram (EMG) recordings from the subscapularis muscle: description of a technique.

Operative treatments for recurrent dislocation of the shoulder usually focus on the subscapularis muscle because it is supposed to contribute to the joint stability. It is of clinical interest to record the EMG from the subscapularis muscle in order to interpret its function. The purpose of the present study was to describe a safe and reliable route to reach the muscle, deeply located between the scapula and the thoracic cage, with fine-wire EMG electrodes. Twenty-four shoulders were investigated in 12 volunteers. A hypodermic needle containing bipolar fine-wire electrodes was inserted in the posterior axillary line with the subjects in the supine position, and the arm held in an abducted and externally rotated position. Three criteria confirmed the location of the electrodes: experience of periosteal pain when the needle reached the costal surface of the scapula, drawing-in of the wires 3-4 cm when the subject adducted his arm, thereby rotating his scapula downward, and raw EMG recorded during typical movements. Additionally, in four shoulders, the electrode location was checked with computed tomography. There were no complications from this technique, and the subjects felt no pain from the fine-wire electrodes during arm movements. We conclude that the described technique is a safe and reliable method of reaching the subscapularis muscle with EMG electrodes.

Adult↗

PubMed1990

Humeral head retroversion in patients with unstable humeroscapular joints.

Humeral head retroversion and shoulder rotation in both the frontal and scapular plane were studied in 34 patients with anterior glenohumeral instability. Twenty-two patients had traumatic anterior shoulder dislocations and another 12 patients had nontraumatic dislocations with generalized joint laxity. Patients with traumatic recurrent dislocations had a smaller than normal retroversion angle in the unstable shoulder. The angles were 26 degrees on the dominant side and 23 degrees on the nondominant side compared with 33 degrees and 29 degrees, respectively, in normal shoulders. The stable contralateral shoulder joint was clinically and roentgenographically similar to the normal shoulder. The patients with nontraumatic dislocations had increased rotation and smaller retroversion angles, irrespective of stability in the shoulder joint. The retroversion angles were 18 degrees for unstable shoulders on the dominant side and 15 degrees on the nondominant side. The retroversion angle of the stable contralateral joint in these patients was less in five of eight shoulders.

Adult↗

PubMed1990

Retroversion of the humeral head in the normal shoulder and its relationship to the normal range of motion.

Retroversion of the humeral head and the range of motion of the shoulder joint in both the frontal and the scapular plane have been studied in 100 shoulder joints in 50 healthy subjects, 25 men and 25 women. The average angle for humeral head retroversion was 33 degrees on the dominant side and 29 degrees for the nondominant side. There was no difference between genders. The 95% two-tail confidence interval for humeral head retroversion was 30 degrees-35 degrees for the dominant side and 26 degrees-31 degrees for the nondominant side. A larger retroversion angle was consistent with an increased range of external rotation. Mean external rotation in 90 degrees abduction was 105 degrees in the frontal plane and 120 degrees in the scapular plane. External rotation in 90 degrees abduction was greater in women than in men, but there was no difference between dominant and nondominant shoulder joints. The range of motion of rotation was found to be greater than the accepted normal values.

Adult↗

PubMed1990

Muscle activity and coordination in the normal shoulder. An electromyographic study.

Muscle activity and coordination in ten shoulders were studied in five healthy subjects using electromyography (EMG) recorded during standardized loaded movements, i.e., flexion, extension, abduction, external rotation, and internal rotation at 0 degrees, 45 degrees, and 90 degrees of abduction. Bipolar surface and intramuscular fine-wire electrodes were used, and the EMG signal was low-pass filtered, full-wave rectified, and time-averaged. Activity from the subscapularis, supraspinatus, infraspinatus, pectoralis major (sternoclavicular part), the anterior, middle, and posterior parts of the deltoid, and the latissimus dorsi was recorded in parallel. In order to allow a comparison of the activity in a subject's different muscles and the activity in specific muscles between different individuals, the EMG was normalized. Muscle activity occurred simultaneously in muscles producing the movement and in antagonistic muscles. Coordination due to muscle contractions plays a significant role in stabilizing the shoulder joint. The infraspinatus, subscapularis, and latissimus dorsi acted as stabilizers during flexion; the subscapularis acted as a stabilizer during external rotation and with the supraspinatus during extension.

Adult↗

PubMed1989

Muscle activity during shoulder dislocation.

EMG activity from eight shoulder muscles in parallel was recorded from 4 patients with generalized joint laxity. During external rotation of the humerus in 45 degrees abduction, humeroscapular dislocation occurred in 2 patients and subluxation in the 2 others. The activity level in the subscapularis was low, and the activation speed was slow. The low muscle activity and delay in activation of the subscapularis muscle may contribute to the instability.

Adult↗

PubMed1989

Lymphangiosarcoma in chronic hereditary oedema (Milroy's disease).

Lymphangiosarcoma arising in chronic lymphoedema is extremely rare. In a reference population of about four million people, during a thirty year period (1957-1987), only four patients were treated for such a tumour. The neoplasm is almost exclusively seen in elderly patients after mastectomy but in two of our patients, reported in this paper, it arose in chronic hereditary oedema (Milroy's disease). In both these patients there was a considerable treatment delay because of wrong diagnosis. The tumour extent was difficult to assess macroscopically and ablative surgery had to be a disarticulation of the involved extremity. Macular or papular purple lesions in a lymphoedematous extremity should be a manifestation of this aggressive neoplasm.

Adult↗

PubMedDate not supplied

Radiologic assessment of humeral head retroversion. Description of a new method.

A radiologic method for assessment of the humeral head retroversion angle has been developed using one radiograph obtained in the semi-axial view. Validity and reliability of the method has been tested. In five healthy volunteers both shoulders were examined both with CT and with the new radiographic method. The average difference in angle determinations between the methods was 1.5 degrees and the maximum difference was 2 degrees. Angle determination on radiographs from 22 healthy shoulders was performed by two independent radiologists. The coefficient of variation for intraobserver measurements was 2.8 per cent and for interobserver measurements it was 4.6 per cent. Three isolated humerus bones were examined in multiple semi-axial projections and the humeral head retroversion was measured. The effect of humeral position (flexion, extension, abduction) on angle assessments was analyzed. A method error exceeding 2 degrees was only seen when the specimens were in an extended or extremely abducted position. It is concluded that with the arm in the correct position measurements of humeral head retroversion can be performed with this method with high accuracy.

Adult↗