Nils Dalén

Bone Mineral Content and Physical Activity

(1974). Bone Mineral Content and Physical Activity. Acta Orthopaedica Scandinavica: Vol. 45, No. 1-4, pp. 170-174.

Bone Mineral Content and Mechanical Strength of the Femoral Neck

The bone mineral content of the femoral neck of 61 autopsy specimens was assayed by x-ray spectrophotometry. The mechanical strength of the specimens was also determined experimentally by applying a compressive force perpendicularly to the shaft. The ultimate force at fracture was obtained from force/displacement plots. A coefficient of correlation of 0.89 between bone mineral content of the femoral neck and the ultimate force at fracture was found. Even when limited to a group of women aged 67-80 a fairly close correlation was found. This indicates that the bone mineral level, measured in vivo, can be used as a criterion of the risk of fracture in elderly women.

Muscle strength, gait, and balance in 20 patients with hip osteoarthritis followed for 2 years after THA

Background Patients with hip osteoarthritis (OA) have muscular weakness, impaired balance, and limp. Deficits in the different limb muscles and their recovery courses are largely unknown, however. We hypothesized that there is persisting muscular weakness in lower limb muscles and an impaired balance and gait 2 years after THA. Patients and methods 20 elderly patients with unilateral OA were assessed before, and 6 and 24 months after surgery for maximal voluntary isometric strength of hip and knee muscles and by gait analysis, postural stability, and clinical scores (HHS, SF-36, EuroQoL). Results Hip muscles showed a remaining 6% weakness compared to the contralateral healthy limb 2 years after THA. Preoperatively and 6 months postoperatively, that deficit was 18% and 12%, respectively. Knee extensors fully recovered a preoperative 27% deficit after 2 years. Gait analysis demonstrated a shorter single stance phase for the OA limb compared to healthy limb preoperatively, that had already recovered at the 6-month follow-up. Balance of two-foot standing showed improvement in both sagittal and lateral sway after operation. All clinical scores improved. Interpretation Muscle strength data demonstrated a slow but full recovery of muscles acting about the knee, but there was still a deficit in hip muscle strength 2 years after THA. Gait and balance recovered after the operation. To accelerate improvement in muscular strength after THA, postoperative training should probably be more intense and target hip abductors.

Reduced muscle radiological density, cross-sectional area, and strength of major hip and knee muscles in 22 patients with hip osteoarthritis

Background Patients with hip osteoarthritis (OA) typically suffer joint pain, and often experience muscular weakness. We hypothesized that substantial atrophy would manifest in multiple muscle groups along the affected limb, resulting in severe muscle dysfunction. Patients and methods We assessed 22 elderly patients with unilateral OA for maximal voluntary isometric strength of hip and knee muscles using a dynamometer that was developed for the purpose. Cross-sectional area (CSA) and radiological density (RD; in Hounsfield units: HU) of hip and knee muscles were assessed using CT. We determined SF-36, HHS, and EQ-5D. Results Hip extension, flexion, adduction, abduction, and knee extension strength were reduced (11– 29%; p < 0.01) in the OA limb relative to the healthy limb. Muscle CSA of hip extensors, flexors, adductors, knee extensors and flexors, but not hip abductors, was reduced (11–19%; p < 0.01) in the OA limb, where RD of all muscle groups except hip flexors was reduced (5–15 HU; p < 0.01). The clinical scores confirmed impairment. Interpretation Major muscles functioning around the hip and knee showed substantial loss of strength and mass, which contributes to the reduced ambulatory capacity of OA patients. Reduced muscle CSA could not fully explain the loss in strength. Infiltration with fat or other non-contractile components, as indicated by a reduced RD, in OA limb muscles was substantial.

Effects of ageing and gender on contractile properties in human skeletal muscle and single fibres

Aim:  The objective of this study is to improve our understanding of the mechanisms underlying the ageing‐ and gender‐related muscle weakness.

Prediction of Mortality in Elderly Patients with Hip Fractures: A Two-Year Prospective Study of 1,944 Patients

Background: Hip fracture patients are reported to have an increased mortality rate compared to the general population. In order to be able to reduce the morbidity and mortality after a hip fracture, our efforts to identify the patients at risk already upon admission to the hospital need to be increased. For such a risk assessment, robust, validated, and reproducible criteria are mandatory. Objective: To determine preoperative factors associated with mortality and to evaluate the combined use of the American Society of Anesthesiologists (ASA) and the Short Portable Mental Status Questionnaire (SPMSQ) to identify patients with an increased mortality rate and to create a predictive model to assess the mortality risk after hip fracture surgery. Methods: A total of 1,944 consecutive patients aged 66 years or older admitted for a hip fracture were included in a prospective cohort study with a 24-month follow-up. The patients were assessed with regard to gender, age, type of hip fracture, smoking habits, comorbidities, general physical health according to the ASA classification, and cognitive function according to the SPMSQ. A higher ASA score indicates an increasingly severe systemic disease and a lower SPMSQ score indicates an increasingly severe cognitive dysfunction. We used Cox proportional hazard models and classification trees to identify the factors associated with mortality. The predictive model was created based on factors that were significantly associated with death and all readily accessible upon admission. Results: The mortality rate during the acute hospitalization period was 4%, at 4 months 16%, and at 24 months 38%. The most prominent factors associated with mortality were high ASA scores, low SPMSQ scores, high age and male gender. The SPMSQ score provided additional information about the survival time, compared to when the ASA score was used alone. Conclusion: The combined use of the ASA classification for assessing physical health and the SPMSQ for assessing cognitive function effectively identified hip fracture patients with an increased mortality rate. We present a predictive model including age, gender, ASA, and SPMSQ that can be used to assess the mortality risk after hip fracture surgery.

Quality of life after a subtrochanteric fracture A prospective cohort study on 87 elderly patients

BACKGROUND The subtrochanteric fracture constitutes approximately 5-10% of all hip fractures. This particular fracture type, owing to its configuration and instability, poses significant challenges to the fixation method, especially in elderly patients with varying degrees of osteoporosis. There has been a gradual change in the operative techniques used to stabilise these fractures leading to the current widespread use of cephalomedullary nails. In contrast to the field of research on patients with the more common femoral neck and trochanteric fractures, few studies have evaluated the health-related quality of life (HRQoL) in patients with subtrochanteric fractures. OBJECTIVE To report the long-term outcome for patients with subtrochanteric fractures treated with a cephalomedullary nail with special regard to the HRQoL. SETTING Four university hospitals. DESIGN A prospective cohort study with a 2-year follow-up. PATIENTS AND METHODS Eighty-seven consecutive elderly patients with a subtrochanteric fracture treated with a cephalomedullary nail. Main outcome measurements were mortality rate, reoperation rate, pain at the hip, walking ability, activities of daily living (ADL) function and HRQoL assessed with the EQ-5D (EQ-5D(index) score). RESULTS The EQ-5D(index) score decreased from 0.73 before fracture to 0.53 at 4 and 12 months and to 0.52 at 24 months. At the final follow-up 80% of the patients reported no or only limited pain at the hip, 46% had regained their prefracture walking ability, 48% their prefracture level of ADL function and 71% had living conditions similar to those before the fracture. The reoperation rate was 8%. The mortality rate was 8% at 4 months, 14% at 12 months and 25% at 24 months. CONCLUSIONS A subtrochanteric fracture in elderly patients had a substantial negative effect on both their short and long-term HRQoL. Although pain at the hip was not a major problem there was an obvious deterioration in walking ability and ADL function. However, the rate of revision surgery was comparatively low which confirms that the cephalomedullary nail constitutes a safe treatment for elderly patients with a subtrochanteric fracture. The data on HRQoL obtained in this study can be used in future healthcare evaluations and to calculate quality-adjusted life-years (QALYs).

Persisting muscle atrophy two years after replacement of the hip

Muscle atrophy has been demonstrated in patients suffering from osteoarthritis of the hip, but little is known about muscular recovery after total hip replacement (THR). A total of 20 patients with unilateral osteoarthritis of the hip were assessed before, six months and two years after THR. The cross-sectional area and radiological density of the muscles of the hip, thigh, calf and back were measured using CT. We hypothesised that the muscles would not recover fully after operation. After two years comparison of the limb with the THR with the healthy limb showed that there was such a reduction in the cross-sectional area in iliopsoas (7.0%; p = 0.006) and the hip adductors (8.4%, p = 0.003) and in the radiological density in gluteus maximus (10.1 Hounsfield units; p < 0.001), gluteus medius/minimus (5.6 Hounsfield units; p = 0.011), iliopsoas (3.9 Hounsfield units; p < 0.001) and the adductors (2.4 Hounsfield units; p = 0.022). Thus, there was persistent muscle atrophy in muscles acting about the hip two years after THR. We suggest that an earlier operation or a more intensive rehabilitation may reverse these changes.

Early mobilization of operated on ankle fractures: Prospective, controlled study of 40 bimalleolar cases

40 patients with dislocated bimalleolar and trimalleolar ankle fractures took part in this randomized study. All ankles were operated on using cerclage, staples and pins. Active ankle movement with weight bearing in an orthosis was compared with active ankle movement without weight bearing using a dorsal splint. Stereophotogrammetric analysis showed small movements in the ankle mortise in both groups but conventional radiography revealed no fracture redislocation. The clinical results did not differ. This study was designed as the second part of a consecutive project. In the first part, early and late weight bearing in a cast without ankle movements was compared (Ahl et al. 1987b). In comparing the first and the second parts of the study, a small but significant increase in fracture instability was observed in the early motion group. No lasting superior clinical result was achieved by early ankle movement. After operation on dislocated bimalleolar ankle fractures, early postoperative weight bearing in a walking cast is recommended.

Bone mineral losses in alcoholics.

Bone mineral measurements were performed at five skeletal sites in seven alcoholics. The mean annual loss of bone mineral in alcoholics was about 2 per cent higher than that of controls.