The interactions of bisphosphonates in solution and as coatings on hydroxyapatite with osteoblasts.

Aseptic loosening is one of the major causes of failure of artificial hip joints, and it can occur for several reasons, including osteolysis of the bone tissue in response to stress shielding or cellular reactions to wear debris. Any treatment of the prosthesis which could minimize the osteolytic response of bone tissue may be able to extend the life-time of the implant. Bisphosphonates are potent inhibitors of osteoclastic bone resorption, and they bind avidly to hydroxyapatite (HA). Coating the prostheses with bisphosphonates may therefore inhibit osteolysis. We have investigated the potential for this approach by determining whether bisphosphonates interact with osteoblasts in vitro. The effects of pamidronate (P), clodronate (C), and etidronate (E) in solution and when coated onto HA were investigated. P inhibited protein and collagen syntheses potently when in solution, but not after being bound to HA. When bound to HA, both P and C increased DNA, protein and collagen syntheses of osteoblasts and may encourage the osseointegration of implants. The pharmacological effects of the bisphosphonates studied altered dramatically after binding to HA. This must be fully investigated before this approach to prolonging prostheses stability can be evaluated.

The response of primary rat and human osteoblasts and an immortalized rat osteoblast cell line to orthopaedic materials: comparative sensitivity of several toxicity indices.

When studying the biocompatibility of orthopaedic biomaterials it is often necessary to discriminate between responses which show mild cytotoxicity. It is therefore essential to use a very sensitive index of toxicity. We have compared the sensitivity of four well-established indices of toxicity: total cell protein content, leakage of lactate dehydrogenase (LDH), reduced glutathione content and the MTT assay, with that of a novel index, alkaline phosphatase (ALP) activity. Comparisons were made by detecting nickel chloride toxicity in osteoblasts. ALP activity, the novel method, proved the most sensitive index of toxicity and it provides a convenient automated assay for assessing the interactions of materials with osteoblasts. The responses to nickel chloride and to aqueous extracts prepared from carbon fibre reinforced epoxy and polyetheretherketone (peek), two candidate materials for orthopaedic implants, were compared in primary and immortalized rat osteoblasts, and in primary human osteoblasts. Although the immortalized rat osteoblast cell line, FFC, was consistently the most sensitive cell type, the responses of the human cells and the FFC cell line were similar in terms of ALP activity throughout the range of nickel concentrations studied. Neither peek nor epoxy material extracts showed a significant decrease in the MTT or ALP responses in any of the three cell types. Our data suggest that immortalized rat osteoblasts may provide an in vitro model system for screening the biocompatibility of orthopaedic polymers.

In vitro biocompatibility testing of polymers for orthopaedic implants using cultured fibroblasts and osteoblasts.

The biocompatibility of two polymers for potential use as orthopaedic implant materials in an isoelastic hip prosthesis was investigated. The interactions of polyetheretherketone (PEEK) and epoxy resin polymers (with and without carbon fibre reinforcement) with both fibroblasts and osteoblasts were tested using cell protein, intracellular reduced glutathione (GSH), leakage of lactate dehydrogenase and the MTT assay as indices of cellular cytotoxicity. The epoxy resin polymer was slightly cytotoxic to and inhibited the growth rate of fibroblasts (as assessed by total cell protein), and depleted GSH in both cell types. In contrast, the PEEK material did not display overt signs of cytotoxicity and, in fact, increased osteoblast cell protein content. This suggests that, of these two materials, PEEK would be the one of choice for development of an isoelastic implant and, in view of its stimulatory effect on osteoblast protein content, it may encourage ingrowth of bone around the prosthesis and thus minimize joint loosening.

The role of the psychologist in multidisciplinary treatments for chronic neck and shoulder pain: a controlled cost-effectiveness study.

This study was designed to determine a cost-effective use of psychologist resources in multimodal cognitive-behavioural treatments (MMCBT) for chronic neck/shoulder pain. A randomised controlled trial was conducted with 66 patients divided in two groups. The first group (A) was treated following the approach of MMCBT with the clinical psychologist only functioning as a "coach" to the other health professionals. In this group, the psychologist had on average 5 hours of input per patients. The second group (B) was treated with the same inpatient MMCBT but with the behavioural component administered by the clinical psychologist directly to the patients. In this second group the psychologist had on average 17 hours of input per patient in the entire intervention. The outcome variables included physical, emotional and social factors, and sick-leave. Both groups showed significant improvements over time. The improvements were evident only in sub-groups, specifically in women. The only significant difference between the groups was in "perceived helplessness" favouring the "psychologist contact" setting. It is concluded that in terms of input of clinical psychology, the treatment setting with the "coaching" technique proved to be the most cost-effective use of the psychologist in the two treatment settings investigated.

Coping with long-term musculoskeletal pain and its consequences: is gender a factor?

We did a descriptive study of 121 patients (71 women and 50 men) to explore the role of gender in coping with long-term intractable pain of the neck, shoulder and back and to determine the consequences of pain. Questionnaires used to assess the dependent variables were the Coping Strategy Questionnaire (CSQ) and the Multidimensional Pain Inventory (MPI). Distinctions were found between men and women. In particular, the coping strategies used by women were those which in previous research had been found to be associated with dysfunction and poor outcome in terms of rehabilitation. Moreover, considering the consequences of pain on daily living, a more complex pattern of related factors was found in women rather than men. Given the high proportion of working women in Sweden with long-term musculoskeletal pain and considering recent observations in controlled studies showing that the benefits of cognitive behaviourally based treatments are confined to women, our findings suggest the need to tailor rehabilitative strategies differently for men and women and point to a research agenda which pays more attention to the distinctive challenges of women in the workplace when they are affected by chronic ailments.

Sports and osteoarthrosis of the hip. An epidemiologic study.

To investigate if participation in sports increases the risk of developing osteoarthrosis of the hip, we did a case-control study on the sports activities of 233 men (up to age 49) who were recent recipients of a prosthesis because of severe idiopathic osteoarthrosis of the hip and 302 men randomly selected from the general population. Assessments of sports, job history, and health status were made by an interview. Men with high exposure to sports of all kinds combined (in hours) had a relative risk to develop osteoarthrosis of the hip of 4.5 compared to those with low exposure. Track and field sports and racket sports seemed to be the most hazardous to the hip joint. Men who had been exposed to high physical loads both from their occupation and sports had a relative risk of 8.5 to develop osteoarthrosis of the hip compared to those with low physical load in both activities. Potential confounding factors, such as age, body mass index, and smoking, were considered. Long-term exposure to sports among men seems to be a risk factor for developing severe osteoarthrosis of the hip; this is increased when combined with heavy load from occupation.

Shoulder tendinitis and its relation to heavy manual work and exposure to vibration.

Three categories of construction industry workers (54 bricklayers, 55 rockblasters, and 98 foremen) were compared in a cross-sectional study. In a structured interview they reported exposure to loads lifted, vibration, and years of manual work. They were also subjected to a clinical investigation including medical history and a detailed shoulder examination. Among the rockblasters 33% had signs of tendinitis in the left and 40% in the right shoulder. Among the bricklayers and foremen 8-17% had signs of shoulder tendinitis. In a multiple logistic regression being a rockblaster compared with being a foreman showed an odds ratio (OR) of 3.33 for left-sided and 1.71 for right-sided shoulder tendinitis. Vibration exposure yielded an OR of 1.84 and 1.66 for the left and right sides, respectively. Vibration exposure or work as a rockblaster seemed to be risk indicators for tendinitis of the shoulders.

Radiographic osteoarthrosis in the acromioclavicular joint resulting from manual work or exposure to vibration.

The hypothesis that manual work and exposure to vibration are antecedents to the development of osteoarthrosis was assessed employing a cross sectional study design. The frequency of osteoarthrosis in the acromioclavicular joint was studied in three groups of workers in the construction industry. Two groups were manual workers (54 bricklayers and 55 rock blasters); the third group consisted of 98 foremen. The radiographic appearance of the right and left acromioclavicular joints was classified into one of five grades of osteoarthrosis. A protocol was developed to assess exposure on the basis of job title, years of manual work, total weight lifted during working life, and total hours of exposure to vibrating tools. Odds ratios for job titles (manual worker v foreman) and for years of manual work as indicators of exposure were of similar magnitude of around 2.5. Construction workers who had lifted more than 709 tonnes had an increased risk of developing severe osteoarthrosis of the right acromioclavicular joint, odds ratio: 2.62 (95% confidence interval (95% CI), 1.13-6.06). The odds ratio for the left side was 7.67 (95% CI, 2.76-21.34). In the analysis of vibration exposure, workers who had been highly exposed to vibration had an odds ratio of 1.99 (95% CI, 1.00-3.92) on the right side and 2.20 (95% CI, 1.07-4.56) on the left. This effect almost disappeared after simultaneous adjustment for manual work. Occupational and ergonomic factors, such as the sum of lifted tonnes during working life, job title, and the sum of years of manual work seem to be risk factors for osteoarthrosis of the acromioclavicular joint, whereas vibration alone was a weaker risk factor.

Diminished space in the acromioclavicular joint in forced arm adduction as a radiographic sign of degeneration and osteoarthrosis.

The purpose of this study was to examine the acromioclavicular joint by radiography under forced arm adduction to demonstrate diminished joint space as a sign of cartilage degeneration and osteoarthrosis. A total of 192 right and left joints were investigated in 96 healthy working men. There were three main results from the manoeuvre: in 135 of the 192 joints the space was reduced, in 33 joints it was unchanged, and in 24 joints the joint space was increased. In 43 joints (22% of the total) a marked reduction of the joint space to 1 mm or less occurred during the manoeuvre; in the remaining 92 joints with space reduction the reduction was less pronounced. A narrow acromioclavicular joint space during forced adduction of the arm indicates cartilage thinning and may be interpreted as a sign of osteoarthrosis.

Hospital care versus home care for rehabilitation after hip replacement.

A pilot study was done to assess the feasibility of reducing the hospital stays of patients with total hip replacement (THR). The length of hospital stay for these patients depends largely on how rehabilitation, mostly physical therapy, is organized. This study shows that not more than a half hour per postoperative day was devoted to care services and rehabilitation activities. It is feasible and less expensive to reduce substantially hospital stay by planned physical therapy in the patient's home. These results have prompted a randomized controlled clinical trial to assess hospital versus home rehabilitation.

Injury surveillance at emergency departments in an urban area. Methodology and quality control.

An injury surveillance system has been developed and tested in a pilot study at two emergency departments in the Stockholm area. The object was to develop an all-age, all-injury registration at all hospital emergency departments and primary care units treating injured patients. The information will be used at the local level for preventive measures, and on a national level for comparison with other areas. All injured patients were given a record-sheet that served both as a registration form and a medical record. The NOMESKO-code was used as a basis for classifying intent, activity, type of location, and injury mechanism. Altogether, 11,327 injured patients were registered. One day each month was randomly selected from the registration for control of registry completeness. The drop-out rate was on average 13%. The reasons were that patients had not been provided with the injury form, or that the copy of the form had not been sent to, or had not reached the Epidemiological Unit where data entry was performed. 6% of the injuries occurred in patients living outside the Stockholm area. The average shortfall-rate in filling in the NOMESKO-code on the registration form was 10%. The rate of registry drop-outs and incomplete forms should decrease when registration has become a routine procedure, provided that the staff can be engaged in the preventive work and the registration procedure can be adjusted to the routines of trauma management in each emergency department.

Occupation and osteoarthrosis of the hip and knee: a register-based cohort study.

A register-based cohort study was performed to investigate if men and women in certain occupations with high physical workload had increased risks of developing severe symptomatic osteoarthrosis of the hip and knee, resulting in hospital care. The study population consisted of 250,217 people from the 1980 census, in blue-collar occupations, who had reported the same occupation in the 1960 and 1970 censuses. The study population was followed for hospital care for osteoarthrosis of the hip and knee during 1981-1983 by linkage to the Swedish Hospital Discharge Register. Different blue-collar occupations were classified as high or low with regard to exposure to forces acting on the hip and knee and the frequencies of the outcomes were compared. Male farmers, construction workers, firefighters and some food processing workers had an excess risk of hospitalization due to osteoarthrosis of the hip. Male farmers, construction workers and firefighters also had increased risks of osteoarthrosis of the knee. Female mail carriers had an excess risk of osteoarthrosis of the hip, and female cleaners, of osteoarthrosis of the knee. The findings support the hypothesis that heavy physical work load contributes to osteoarthrosis of the hip and knee.

Coxarthrosis and physical work load.

A case-referent study was performed on the possible relationship between physical work loads and an increased risk of developing coxarthrosis. The cases were 239 male recipients of a hip prosthesis as a result of severe idiopathic coxarthrosis; the referents were 302 men randomly selected from the general population. The work load was assessed through an interview and a self-administered questionnaire on the men's specific work periods. Men highly exposed to dynamic or static work loads had an increased relative risk of 2.42 (95% confidence interval 1.45-4.04) for developing coxarthrosis when compared with men with low exposure. Men with high exposure to heavy lifting between the ages of 30 and 49 years had the highest relative risk, 3.31 (95% confidence interval 1.97-5.57). Long-time exposure to physical work loads seems to be a risk factor for severe coxarthrosis among men.

Total hip arthroplasty. A comparison between cemented and press-fit noncemented fixation.

This study compares cemented (Charnley) with noncemented (Honart Patel-Garches) total hip arthroplasty. 150 patients with osteoarthritis, rheumatoid arthritis, and miscellaneous conditions were randomized into either group with 75 in each. Patients were evaluated over 5 postoperative years with examinations at 6 months, at 1 year, and then annually. Each examination involved clinical assessment, objective gait analysis, and radiographic examination. The Charnley group improved faster than the HP-Garches group during the first 2 years. At the last evaluation the results were excellent or good in 79% in the Charnley group and 70% in the HP-Garches group. In the HP-Garches group midthigh pain occurred in 64%. Five patients with Charnley prostheses (6.7%) and 14 patients with HP-Garches prostheses (18.7% had revision surgery to correct mechanical loosening. Standard radiography revealed radiolucent zones in both groups, but this could not be related to the clinical outcome despite radiolucency being present in all noncemented replacements on the femoral side. Objective gait analysis confirmed inferior clinical results at 6 months in the HP-Garches group. There was no significant difference between the groups at the most recent evaluation. Our findings are not consistent with earlier optimistic expectations on press-fit noncemented total hip arthroplasties.

Risk exposure and incidence of injuries in school physical education at different activity levels.

Pupils in the age range of 14-19 years in the schools of a municipality in Sweden were observed prospectively for one year for acute injuries during school physical education (n = 2089). Pupils registered in the Injury Surveillance System for an acute injury sustained during physical education classes and treated by a physician were interviewed. The number of observed injuries was 53. The incidence rate as a ratio of injury and estimated time of activity has been calculated. Physical activity during leisure time was investigated by a mailed questionnaire to a random sample of 7% of the population in the same age range. Levels of physical activity during leisure time of the injured pupils were related to activity levels in the whole population. An increased risk of injury (7 times) was found in pupils with a low activity level, compared to those with a medium or high level, and the risk of injury in females with a sedentary life style was 10 times as high as in active females.