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Biomedical subjects

R Lorentzon

Publications and source records attributed to R Lorentzon.

143 records · Page 8Linked to original sources
PubMed1975

Primary liposarcoma of bone.

A case is presented of a rare primary liposarcoma of bone localized to the major trochanter of the left femur of a 52-year-old female. Despite combined treatment with curettage and irradiation with a total dose of 4,500 rad the neoplasm showed rapid invasive growth with destruction of the bone, spread to the iliac fossa and outgrowth through the operation wound. Approximately 5 months after admission the patient succumbed due to widespread metastases in the lungs, liver and left kidney. The histopathology, clinical course and treatment of this rare neoplasm of the bone are discussed.

Biopsy↗
PubMed1975

Giant-cell tumor of bone. A demographic, clinical, and histopathological study of all cases recorded in the Swedish Cancer Registry for the years 1958 through 1968.

All seventy-five cases recorded as giant-cell tumor of bone in the Swedish Cancer Registry for the years 1958 through 1968 were analyzed. At reexamination, fifty-three cases constituted genuine giant-cell tumor of bone and twenty cases were so-called "giant-cell variants". The genuine giant-cell tumors showed a significantly higher incidence in the urban than in the rural population. The recurrence rate was 42 per cent. Patients under the age of twenty-five rarely had recurrences. A high recurrence rate was found among patients with tumors located in the distal end of the femur and the proximal end of the tibia. Tumors penetrating through the bone cortex were more aggressive than those located entirely within bone, regardless of tumor size and presence or absence of spontaneous fracture. A malignant course was found in 11.3 per cent of cases, predominantly in patients with tumors in the femur. Histopathological grading was of no prognostic value. Primary en bloc resection with or without prosthetic replacement is recommended in patients over the age of twenty-five.

Adolescent↗
PubMed1975

Malignant hemangioendothelioma of bone.

The clinical and histopathological characteristics are described in seven cases of malignant hemangioendothelioma of bone. This rare neoplasm affects all age groups and almost any bone. Metastases appear in the skeleton even before such lesions are seen on pulmonary roentgenograms. Prognosis is poor, with a five-year survival for only two of the six patients in this series. One patient is still alive and free of symptoms more than twelve years after diagnosis of widespread tumor destruction of the frontal skull bones, which was successfully controlled by radiation therapy. In addition, a recently diagnosed case of this tumor arising in a chronic non-fistulous osteomyelitic bone is described.

Adult↗
PubMedDate not supplied

Injuries in international ice hockey. A prospective, comparative study of injury incidence and injury types in international and Swedish elite ice hockey.

In this prospective study, we have investigated incidence, nature, and mechanisms of injury in the Swedish national hockey team during 40 international games. There were 19 injuries associated with absence from practice or games, and 17 facial lacerations. The incidence of injuries associated with absence was 79.2 per 1,000 player-game hours, compared to the corresponding incidence of 78.4 found for Swedish national hockey. The incidence of facial wounds was 70.8 per 1,000 player-game hours, compared to the incidence of 21.8 for Swedish national hockey. The high incidence of facial injuries in international hockey is due to a high rate of stick contact injuries. Stricter enforcement of rules and more widespread use of visors would reduce the number of facial injuries.

Adult↗
PubMedDate not supplied

Incidence, nature, and causes of ice hockey injuries. A three-year prospective study of a Swedish elite ice hockey team.

In this prospective study, we have investigated incidence of injuries of different severity, types of injury, and mechanisms of injury during ice hockey practice and games. One Swedish elite hockey team was closely observed during three seasons (1982 to 1985). There was a total number of 95 injuries and 29 facial lacerations. The majority of injuries were minor (73%) and only 8% were classified as major. Seventy-six percent of the injuries occurred during games and 24% during practice. The incidence of injury during practice was 1.4 per 1,000 player-practice hours and 78.4 per 1,000 player-game hours. In comparison with other sports, the incidence of injury during hockey practice is very low, while that during games is high. Eighty percent of the injuries were caused by trauma and 20% by overuse. The most common types of injury were contusions, strains, and sprains. Complete tear of the medial collateral ligament of the knee was the most common severe injury. Most injuries resulted from body contact, predominantly tackling (checking), and from puck or stick contact. A reduction of the number of minor and moderate injuries should be possible by stricter enforcement of the hockey rules, especially against stick violations, and more widespread use of visors.

Adult↗
PubMedDate not supplied

Reconstruction of the anterior cruciate ligament. Long-term effects of different knee angles at primary immobilization and different modes of early training.

The clinical results in 29 patients who had undergone ACL reconstruction with quadriceps-patellar tendon graft over-the-top were studied at an average of 28 months postoperatively. Postoperative immobilization was at either 30 degrees (N = 17) or 70 degrees (N = 12) of knee flexion for 6 weeks. All patients then followed a common preparatory training program for 8 weeks. In the 14th postoperative week the patients were put on either progressive resistance training (N = 12) or isokinetic training (N = 17) for 6 weeks, after which all had identical training. Independent of primary knee immobilization angle or training regimens, no differences could be demonstrated with respect to stability, range of motion, function, or isokinetic mechanical output. For all patients, Lysholm knee function score improved from 60.5 to 93.6 (P less than 0.001) and activity level from 3.9 to 6.3 (P less than 0.001). Isokinetic peak torque, contractional work, and mean power of the quadriceps at 30, 90, and 180 deg/sec were lower in the injured compared to the noninjured leg (78% to 90%; P less than 0.01) both preoperatively and at followup, and there were no significant differences between the preoperative and follow-up values. Clinical stability improved (P less than 0.001) in 19 of the 29 patients (66%) and in 11 of those 17 patients with early isokinetic training (65%). Performance tests were normal in 23 of 29 patients (79%), with minor abnormalities in the rest.

Adolescent↗
PubMedDate not supplied

Isokinetic muscular performance of the quadriceps in elite ice hockey players.

On four occasions during a period of 17 months, isokinetic maximum knee extensor output (peak torque and contractional work) and input (integrated electromyographic activity) during single and repetitive contractions were measured in 10 male elite ice hockey players. The tests were performed in the middle and at the end of the competitive season, and after two office training periods involving different types of training. No significant changes in peak torque at single maximum contractions occurred for the whole group of players during the investigation. Nor did the slope of decline in contractional work or the plateau level of the ratio of contractional work:integrated electromyographic activity during repetitive contractions change significantly. The most obvious finding was great interindividual differences in muscular performance. Intraindividually, changes in both peak torque as well as in slope of decline in contractional work and in plateau level of the ratio of contractional work:integrated electromyographic activity occurred during the different training periods. We conclude that local muscle adaptations, measured by isokinetic procedures, occur in the quadriceps as a result of ordinary training and games in elite ice hockey players. Because of the great interindividual differences in muscular performance and the different responses to similar training, we suggest individual programs for leg muscle training in ice hockey players.

Adult↗
PubMedDate not supplied

Thigh musculature in relation to chronic anterior cruciate ligament tear: muscle size, morphology, and mechanical output before reconstruction.

Eighteen male patients who had untreated chronic ACL rupture were studied in order to evaluate thigh muscle size, morphology, and isokinetic performance of the quadriceps muscle. Computed tomography disclosed a 5.1% mean atrophy of the quadriceps (P less than 0.05), 2.1% slight hypertrophy of the hamstrings (P less than 0.05), and also nonsignificant changes of all other muscle areas of the injured thigh. Muscle morphology (m. vastus lateralis) was normal in 11 biopsy specimens, whereas minor abnormalities (irregular shape or hypotrophy) could be seen in the rest. Isokinetic mechanical output of the knee extensors was 71% to 87% of that of the noninjured limb (P less than 0.01), and the mechanical output corrected for differences in quadriceps cross-sectional area was significantly lower in the injured than the uninjured limb. As there were no significant correlations between isokinetic performance and muscle size or qualitative morphology or morphometric data, the strength decrease cannot be explained by muscle atrophy or structural changes per se. We conclude that nonoptimal activation of the muscles during voluntary contractions is probably the most important causative mechanism of the strength decrease found in patients who have chronic symptomatic ACL tear.

Adult↗
PubMedDate not supplied

Chronic Achilles tendinitis and calf muscle strength.

We evaluated 10 men and 3 women (mean age, 44 +/- 8.5 years) with chronic Achilles tendinitis who underwent surgical treatment. Surgery was followed by immobilization in a weightbearing below-the-knee plaster cast for 6 weeks and a stepwise increasing strength training program. We prospectively studied calf muscle strength on the injured and noninjured sides preoperatively and at 16, 26, and 52 weeks postoperatively. Preoperatively, concentric peak torque in dorsiflexion at 90 deg/sec and plantar flexion at 225 deg/sec was significantly lower on the injured side. Postoperatively, concentric plantar flexion peak torque on the injured side increased significantly between Weeks 16 and 26 at 90 deg/sec but was significantly lower than the noninjured side from Weeks 16 to 52 at 90 and 225 deg/sec. Dorsiflexion peak torque at 90 and 225 deg/sec increased between Weeks 0 and 26 and was significantly higher on the injured side at Week 26. Eccentric plantar flexion peak torque was significantly lower on the injured side at Week 26 but not at 1 year. This prospective study demonstrates that 6 months of postoperative rehabilitation for chronic Achilles tendinitis is not enough to recover concentric and eccentric plantar flexion muscle strength compared with the noninjured side.

Achilles Tendon↗
PubMedDate not supplied

Achilles tendinosis and calf muscle strength. The effect of short-term immobilization after surgical treatment.

We prospectively studied calf muscle strength in 7 men and 4 women (mean age, 40.9 +/- 10.1 years) who had surgical treatment for chronic Achilles tendinosis. Surgery was followed by immobilization in a weightbearing below-the-knee plaster cast for 2 weeks followed by a stepwise increasing strength training program. Strength measurements (peak torque and total work) were done preoperatively (Week 0) and at 16, 26, and 52 weeks postoperatively. We measured isokinetic concentric plantar flexion strength at 90 and 225 deg/sec and eccentric flexion strength at 90 deg/sec on both the injured and noninjured sides. Preoperatively, concentric and eccentric strength were significantly lower on the injured side at 90 and 225 deg/sec. Postoperatively, concentric peak torque on the injured side decreased significantly between Weeks 0 and 16 and increased significantly between Weeks 26 and 52 at 90 deg/sec but was significantly lower than that on the noninjured side at all periods and at both velocities. The eccentric strength was significantly lower on the injured side at Week 26 but increased significantly until at Week 52 no significant differences between the sides could be demonstrated. It seems, therefore, that the recovery in concentric and eccentric calf muscle strength after surgery for Achilles tendinosis is slow. We saw no obvious advantages in recovery of muscle strength with a short immobilization time (2 weeks) versus a longer (6 weeks) period used in a previous study.

Achilles Tendon↗
PubMedDate not supplied

Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis.

We prospectively studied the effect of heavy-load eccentric calf muscle training in 15 recreational athletes (12 men and 3 women; mean age, 44.3 +/- 7.0 years) who had the diagnosis of chronic Achilles tendinosis (degenerative changes) with a long duration of symptoms despite conventional nonsurgical treatment. Calf muscle strength and the amount of pain during activity (recorded on a visual analog scale) were measured before onset of training and after 12 weeks of eccentric training. At week 0, all patients had Achilles tendon pain not allowing running activity, and there was significantly lower eccentric and concentric calf muscle strength on the injured compared with the noninjured side. After the 12-week training period, all 15 patients were back at their preinjury levels with full running activity. There was a significant decrease in pain during activity, and the calf muscle strength on the injured side had increased significantly and did not differ significantly from that of the noninjured side. A comparison group of 15 recreational athletes with the same diagnosis and a long duration of symptoms had been treated conventionally, i.e., rest, nonsteroidal antiinflammatory drugs, changes of shoes or orthoses, physical therapy, and in all cases also with ordinary training programs. In no case was the conventional treatment successful, and all patients were ultimately treated surgically. Our treatment model with heavy-load eccentric calf muscle training has a very good short-term effect on athletes in their early forties.

Achilles Tendon↗
PubMedDate not supplied

Acute Achilles tendon rupture in badminton players.

All patients with badminton-related acute Achilles tendon ruptures registered during 1990 to 1994 at the University Hospital of Umeå were retrospectively followed up using a questionnaire. Thirty-one patients (mean age, 36.0 years), 27 men and 4 women, were included. Thirty patients (97%) described themselves as recreational players or beginners. The majority of the injuries (29 of 31, 94%) happened at the middle or end of the planned game. Previous local symptoms had been noticed by five patients (16%). Long-term results showed that patients treated with surgery had a significantly shorter sick leave absence than patients treated without surgery (50 versus 75 days). There was no obvious selection favoring any treatment modality. None of the surgically treated patients had reruptures, but two reruptures occurred in the nonsurgically treated group. There seemed to be fewer remaining symptoms and a higher sports activity level after the injury in the surgically treated group. Our results indicate that local muscle fatigue may interfere with strength and coordination. Preventive measures such as specific treatment of minor injuries and adequate training of strength, endurance, and coordination are important. Our findings also indicate that surgical treatment and careful postoperative rehabilitation is of great importance among badminton players of any age or sports level with Achilles tendon rupture.

Achilles Tendon↗
PubMedDate not supplied

Anatomic variations of the accessory soleus muscle.

Four cases of accessory soleus muscle are presented. By means of soft tissue radiography and computed tomography the course of the accessory muscle as well as its exact site and mode of insertion could be determined. It was found that the accessory muscle in these four cases showed four different varieties of insertion, i.e. along the tendon of Achilles, fleshy to the upper surface of the calcaneus, by a separate tendon to the upper surface of the calcaneus and fleshy to the medial surface of the calcaneus. These variations may be of importance in the planning of operative treatment. Therefore, meticulous radiologic examinations as depicted in this study are recommended before surgery.

Adolescent↗