Bengt Nordgren

Isometric Strength and Endurance in Patients with Severe Rheumatoid Arthritis or Osteoarthrosis in the Knee Joints

Maximum isometric muscle strength on extension and flexion of the knee joints and endurance on extension has been studied in patients with rheumatoid arthritis (RA) and osteoarthrosis (OA), with such severe degeneration of the knees that arthroplasty was indicated. This material was compared with a group of healthy volunteers. The reduction in muscle strength was most pronounced in the RA group, which had 30-45% of the strength of the healthy volunteers. In the OA group the strength, similarly compared, was 55-70%. The difference is explained by the effect of the rheumatic disease on the muscles. The results indicate that in therapeutic measures due to trauma or in joint surgery, methods that contribute to a further decrease in muscle strength, e.g. immobilization with casts, bandages, or traction treatment, should be avoided.

ON THE RELIABILITY AND USEFULNESS OF METHODS FOR GRIP STRENGTH MEASUREMENT

The purposes of this investigation were to assess the accuracy of a grip strength measuring instrument, the Grippit, to modify previously developed methods for measuring maximal isometric grip strength (12) and to evaluate the reliability of these methods, with the use of the Grippit. Grip strength during short (maximal voluntary isometric strength, MVC) and sustained (SMVC) contractions was measured. The modifications concerned the definitions of MVC and SMVC, the measuring position, the intervals between trials and sessions, and the recording procedure. The intra-observer reliability study comprised 29 healthy subjects, and the inter-observer study 10 other healthy subjects. The Grippit had very high precision. The intra-observer reliabilities of MVC and SMVC measurements were improved compared to those with the previous methods (12). The inter-observer reliability was very high.

CLINICAL SYMPTOMS RELATED TO MUSCULOSKELETAL NECK-SHOULDER PAIN AND MOBILITY IN THE CERVICO-THORACIC SPINE

In a cross-sectional study 142 male and 139 female workers participated in a self-report questionnaire and a clinical examination. The aim of this study was to use the cervico-thoracic ratio (CTR), a clinical method for measuring segmental mobility between C7 and T5, to evaluate the influence of segmental mobility in neck-shoulder pain and different subjectively experienced symptoms. The study showed that reduced relative mobility at levels C7-T1 and T1-T2 significantly predicted neck-shoulder pain and the symptom weakness in the hands. The strongest relationship between segmental mobility and symptoms was found among subjects classified as having an inverse C7-T1 function, defined as equal or less mobility in motion segment C7-T1 compared to T1-T2. Reduced mobility explained 14% of neck-shoulder pain and 15% of weakness in the hands. It is suggested that deviation from synchronous distribution of mobility between motion segments C7-T1 and T1-T2 might be a factor provoking joint mechano receptors.

Isokinetic knee extension strength and pain before and after advancement osteotomy of the tibial tuberosity

SummaryIn 30 patients with patellofemoral chondromalacia and osteoarthrosis the maximal isokinetic knee extension strength was measured. The pain evoked during the recordings was rated on a nine-grade scale. The peak extension torques were markedly lower than in the non-diseased knee and in a reference group of healthy volunteers. Twenty months after advancement of the tibial tuberosity, the muscle strength was significantly increased and pain significantly alleviated, well parallelling the clinical improvement. Intra-articular anaesthesia almost instantaneously increased the knee extension torque considerably, although knee pain was unchanged.ZusammenfassungBei 30 Patienten mit Chondromalacia patellae oder femoropatellarer Arthrose wurde die maximale isokinetische Kniestreckkraft bestimmt. Nach jeder Messung gab der Patient die Intensität des Knieschmerzes an einer neun-Punkte-Skala an. Verglichen mit dem gesunden Bein und einer normalen Referenzgruppe war die Streckkraft stark erniedrigt. Durchschnittlich 20 Monate nach Ventralisierung der Tuberositas tibiae wurde eine signifikante Erhöhung der isokinetischen Muskelkraft sowie eine signifikante Verminderung des Anstrengungsschmerzes notiert, welche mit der klinischen Verbesserung der Patienten in gutem Einklang standen. Intraartikuläre Anaesthesie führte trotz unveränderten Knieschmerzes fast momentan zu einer Vervielfachung der Streckkraft.

Methods for Measuring Maximal Isometric Grip Strength during Short and Sustained Contractions, Including Intra-rater Reliability

The purposes of this study were to develop methods for measuring maximal isometric grip strength during short and sustained contractions in a laboratory setting, and to evaluate the test-retest reliability of these methods in short- and long-term perspectives. Eleven healthy men and women were assessed on four occasions. Maximal voluntary isometric grip strength (MVC) was measured in standardized and optional positions, and sustained maximal isometric strength (SMVC) in the standardized position. The results indicated that three trials in a session might be insufficient to obtain a true measure of MVC. The within-session and test-retest reliability of the described multi-trial procedure was considered satisfactory. The mean score of the last three trials tended to show the highest short-term and long-term variability. There were no clear differences between scores obtained in standardized and optional positions. The standardized position seemed more consistently to yield higher test-retest reliability and lower variability over time. The described method for measuring SMVC, expressed as area and peak score, had high test-retest reliability and an acceptable degree of short-term and long-term variability. The time taken to reach the peak score was not a reliable measure.

Physical capacity and training in a group of young adult mentally retarded persons.

Through the initiative of the ALA Council, a foundation for the mentally retarded, a group of young retarded persons (age 19-39 years, 39 men and 24 women) selected of those occupied in sheltered workshops for the mentally retarded, was studied. The aim was to investigate their potentialities for adaptation to a normal life (including industrial work and social activities). The mental retardation constituted the domi-

Isometric Muscle Strength and Endurance After Knee Arthroplasty with the Modular Knee in Patients with Osteoarthrosis and Rheumatoid Arthritis

Maximum isometric muscle strength and endurance were used in an investigation of knee extension and knee flexion in patients with rheumatoid arthritis (RA) and osteoarthrosis (OA) with such severe changes of the joint that arthroplasty with the Modular prosthesis was performed. The measurements were done preoperatively and 3, 12, 24 and 36 months postoperatively. Muscle strength preoperatively was very weak compared with that of a group of healthy persons. The muscle strength 3 months postoperatively remained unchanged, which could mean a very slight trauma from the operation, very good pain relief and efficient physiotherapy. During the first 2 years the maximum isometric muscle strength was significantly increased both in patients with RA and in those with OA. Thereafter there was no increase in the RA patients, whereas in women with OA there was an improvement up to 3 years postoperatively. The improvement in the flexion strength was greater than that of the extension strength, thus indicating the importance of postoperative training of extension strength. Isometric muscle strength measurements show that there is an equalization between the non-diseased knee and the one operated with the Modular knee.

Evaluation of a Dynamometer for Measurement of Isometric and Isokinetic Torques

A modified version of the original Cybex II dynamometer with a temperature compensated strain gauge transducer has been evaluated. It was found that the calibration constant was dependent of the vertical load of the device. The ratio (k) between the applied and the recorded torque is angle independent during extension and k is equal to 1.18 and during flexion k is angle dependent and can be expressed as k = -.0008 theta + 1.208, where theta is the angle of flexion.

CORRELATIONS BETWEEN MUSCULAR STRENGTH AND INDUSTRIAL WORK PERFORMANCE IN MENTALLY RETARDED PERSONS

An important task with mentally retarded persons is to place them in an occupation which they can manage without difficulties. With this goal in mind, a group of young adult mentally retarded persons, presented in a previous report (2) underwent evaluation, at the workshops of the ALA centre, Uppsala, of their performance in industrial work. It was considered of interest to determine whether this performance was influenced by muscular strength. In the present study measurements were therefore made of the isometric maximal muscular strength in essentially the same group of persons, and the different components of the test battery used were correlated, by multiple regression analysis, with their performance in industrial work. The studies in this group were made on 42 male and 31 female persons, of ages 19--39 years, with different degrees of mentaI retardation.

Isokinetic knee extension strength and pain before and after correction of recurrent patellar dislocation

SummaryThe maximal isokinetic knee extension strength was measured in 20 patients before and after surgical correction of recurrent dislocations of the patella and the pain evoked during the recordings was rated. The preoperative muscle strength was significantly higher and pain was less severe than in a previously studied group of patients with chondromalacia or patellofemoral osteoarthrosis.Twenty months after patella realignment by a new surgical procedure including an extensive lateral release and anteromedial displacement of the tibial tuberosity by an oblique osteotomy through the anterior crest of the tibia, a significant decrease of patellofemoral pain and a slight increase of muscle strength was noted.ZusammenfassungBei 20 Patienten mit chronisch rezidivierenden Patellarluxationen wurde die maximale isokinetische Kniegelenkstreckkraft und die Schmerzintensität während der Messungen bestimmt. Die präoperative Muskelkraft war signifikant höher als in einer zuvor studierten Patientengruppe mit Chondromalazie oder femoropatellarer Arthrose, und der Anstrengungsschmerz war geringer.Zwanzig Monate nach operativer Korrektur der Patellainstabilität durch extensive laterale Kapselspaltung und anteromediale Transposition der Tuberositas tibiae durch eine neuentwickelte Schrägosteotomie durch die vordere Schienbeinkante wurde eine signifikante Minderung des Schmerzes und eine leichte Verbesserung der Streckkraft im Kniegelenk notiert.