Antti Malmivaara

Outcome measures for low back pain research. A proposal for standardized use.

Study Design. An international group of back pain researchers considered recommendations for standardized measures in clinical outcomes research in patients with back pain. Objectives. To promote more standardization of outcome measurement in clinical trials and other types of outcomes research, including meta‐analyses, cost‐effectiveness analyses, and multicenter studies. Summary of Background Data. Better standardization of outcome measurement would facilitate comparison of results among studies, and more complete reporting of relevant outcomes. Because back pain is rarely fatal or completely cured, outcome assessment is complex and involves multiple dimensions. These include symptoms, function, general well‐being, work disability, and satisfaction with care. Methods. The panel considered several factors in recommending a standard battery of outcome measures. These included reliability, validity, responsiveness, and practicality of the measures. In addition, compatibility with widely used and promoted batteries such as the American Academy of Orthopaedic Surgeons Lumbar Cluster were considered to minimize the need for changes when these instruments are used. Results. First, a six‐item set was proposed, which is sufficiently brief that it could be used in routine care settings for quality improvement and for research purposes. An expanded outcome set, which would provide more precise measurement for research purposes, includes measures of severity and frequency of symptoms, either the Roland or the Oswestry Disability Scale, either the SF‐12 or the EuroQol measure of general health status, a question about satisfaction with symptoms, three types of disability days, and an optional single item on overall satisfaction with medical care. Conclusion. Standardized measurement of outcomes would facilitate scientific advances in clinical care. A short, 6‐item questionnaire and a somewhat expanded, more precise battery of questionnaires can be recommended. Although many considerations support such recommendations, more data on responsiveness and the minimally important change in scores are needed for most of the instruments.

Standardized physical examination protocol for low back disorders : Feasibility of use and validity of symptoms and signs

A standardized examination protocol was developed for the assessment of low back disorders in primary care. The protocol was found feasible in the occupational health service setting. The interexaminer repeatability between an occupational physician and an occupational physiotherapist was good for most items. The predictive validity of different symptoms and signs was investigated with regard to future sick leaves due to low back disorders. Relief of pain when lying, severe trouble at work caused by pain, continuous pain, and pain in the leg or numbness or diminished sensitivity in the foot predicted sick leaves. Of physical signs, pain in the low back or buttock during lateral flexion and a side difference > or = 20 degrees in the straight-leg-raising angle were predictors for sick leaves. The predictive validity of the protocol items should be tested in another patient population before conclusions can be drawn concerning the external validity of our results.

Hallux valgus: immediate operation versus 1 year of waiting with or without orthoses: A randomized controlled trial of 209 patients

Hallux valgus operations can not always be done immediately because of long waiting lists. In this study, 209 consecutive patients (mean age 48 years, 93% female) with a painful hallux valgus were randomized into 3 groups: immediate operation or 1 year waiting with or without foot orthoses. The follow-up period was 2 years. The main outcome measurement was the intensity of pain during walking. During the first year, 64/71, 0/69 and 4/69 patients were operated on in the surgery, orthosis and no orthosis groups, respectively, and during the 2-year follow-up, 66, 43 and 48, respectively. At the 1-year follow-up, the pain was least intense in the surgery group. At the 2-year follow-up, the intensity of pain was similar in all groups. The satisfaction with treatment was best in the surgery and orthosis groups. The total costs of care were similar in all groups. We conclude that immediate operation is superior to delayed operation or foot orthoses. However, if this is not possible because of limited possibilities for surgery, waiting for 1 year, with or without an orthosis, does not jeopardize the final outcome.

Learning Curve for New Technology? A Nationwide Register-Based Study of 46,363 Total Knee Arthroplasties

BACKGROUNDnThe risk of early revision is increased for the first patients operatively treated with a newly introduced knee prosthesis. In this study, we explored the learning curves associated with ten knee implant models to determine their effect on early revision risk.nnnMETHODSnWe studied register data from all seventy-five surgical units that performed knee arthroplasty in Finland from 1998 to 2007. Of 54,925 patients (66,098 knees), 39,528 patients (46,363 knees) underwent arthroplasty for osteoarthritis of the knee with the ten most common total knee implants and were followed with complete data until December 31, 2010, or the time of death. We used a Cox proportional-hazards regression model for calculating the hazard ratios for early revision for the first fifteen arthroplasties and subsequent increments of numbers of arthroplasties.nnnRESULTSnWe found large differences among knee implants at the introduction with regard to the risk of early revision, as well as for the overall risk of early revision. A learning curve was found for four implant models, while six models did not show a learning effect on the risk of early revision. The survivorship of the studied prostheses showed substantial differences.nnnCONCLUSIONSnKnee implants have model-specific learning curves and early revision risks. Some models are more difficult to implement than others. The manufacturers should consider the learning effect when designing implants and instrumentation. The surgeons should thoroughly familiarize themselves with the new knee implants before use.

Individual and Regional-level Factors Contributing to Variation in Length of Stay After Cerebral Infarction in Six European Countries

Using patient-level data for cerebral infarction cases in 2007, gathered from Finland, Hungary, Italy, the Netherlands, Scotland and Sweden, we studied the variation in risk-adjusted length of stay (LoS) of acute hospital care and 1-year mortality, both within and between countries. In addition, we analysed the variance of LoS and associations of selected regional-level factors with LoS and 1-year mortality after cerebral infarction. The data show that LoS distributions are surprisingly different across countries and that there is significant deviation in the risk-adjusted regional-level LoS in all of the countries studied. We used negative binomial regression to model the individual-level LoS, and random intercept models and ordinary least squares regression for the regional-level analysis of risk-adjusted LoS, variance of LoS, 1-year risk-adjusted mortality and crude mortality for a period of 31-365 days. The observed variations between regions and countries in both LoS and mortality were not fully explained by either patient-level or regional-level factors. The results indicate that there may exist potential for efficiency gains in acute hospital care of cerebral infarction and that healthcare managers could learn from best practices.

Hip prosthesis introduction and early revision risk A nationwide population-based study covering 39,125 operations

Background and purpose Little is known about the effect of the learning curve for different types of total hip arthroplasties (THAs). We investigated the prostheses survival of THAs just after the implementation of a model new to the hospital, and compared these results with the results of THAs done when more than 100 implantations had been undertaken. In addition, we investigated whether differences exist between different types of femoral stems and acetabular cups at the early implementation phase. Patients and methods We used comprehensive registry data from all units (n = 76) that performed THAs for primary osteoarthritis in Finland between 1998 and 2007. Complete data including follow-up data to December 31, 2010 or until death were available for 33,819 patients (39,125 THAs). The stems and cups used were given order numbers in each hospital and classified into 5 groups: operations with order number (a) 1–15, (b) 16–30, (c) 31–50, (d) 51–100, and (e) > 100. We used Cox’s proportional hazards modeling for calculation of the adjusted hazard ratios for the risk of revision during the 3 years following the implementation of a new THA endoprosthesis type in the groups. Results Introduction of new endoprosthesis types was common, as more than 1 in 7 patients received a type that had been previously used in 15 or less operations. For the first 15 operations after a stem or cup type was introduced, there was an elevated risk of revision (hazard ratio (HR) = 1.3, 95% CI: 1.1–1.5). There were differences in the risk of early revision between stem and cup types at implementation. Interpretation The first 15 operations with a new stem or cup model had an increased risk of early revision surgery. Stems and cups differed in their early revision risk, particularly at the implementation phase. Thus, the risk of early revision at the implementation phase should be considered when a new type of THA is brought into use.