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Biomedical subjects

Kevin McGuire

Publications and source records attributed to Kevin McGuire.

3 recordsLinked to original sources

Postthrombotic syndrome after asymptomatic deep vein thrombosis following total knee and hip arthroplasty.

Lower extremity deep vein thrombosis (DVT) is relatively common after total knee arthroplasty (TKA) and total hip arthroplasty (THA). In this study, we sought to identify whether post-thrombotic syndrome is a significant risk in patients with asymptomatic DVT after TKA and THA. Included in the study were 186 patients (203 lower extremities) who had undergone routine lower extremity venography after TKA or THA between 1989 and 1993. Patients were contacted a minimum of 7 years after surgery. Postoperative varicose veins occurred in 8% of limbs without DVT compared with 12% of limbs with DVT. Hyperpigmentation occurred in 13% of limbs without DVT and in 16% and 18% of limbs with proximal and distal DVT, respectively. Swelling occurred in 6% of limbs without DVT, in 8% of limbs with proximal DVT, and in 12% of limbs with distal DVT. None of these differences was statistically significant, and there were no differences for proximal versus distal DVT. There was no significant increase in risk for postthrombotic syndrome after asymptomatic proximal or distal DVT after TKA or THA.

Arthroplasty, Replacement, Hip↗

Statistical sampling and hypothesis testing in orthopaedic research.

The purpose of the current article was to review the process of hypothesis testing and statistical sampling and empower readers to critically appraise the literature. When the p value of a study lies above the alpha threshold, the results are said to be not statistically significant. It is possible, however, that real differences do exist, but the study was insufficiently powerful to detect them. In that case, the conclusion that two groups are equivalent is wrong. The probability of this mistake, the Type II error, is given by the beta statistic. The complement of beta, or 1-beta, representing the chance of avoiding a Type II error, is termed the statistical power of the study. We previously examined the statistical power and sample size in all of the studies published in 1997 in the American and British volumes of the Journal of Bone and Joint Surgery, and in Clinical Orthopaedics and Related Research. In the journals examined, only 3% of studies had adequate statistical power to detect a small effect size in this sample. In addition, a study examining only randomized control trials in these journals showed that none of 25 randomized control trials had adequate statistical power to detect a small effect size. However, beta, or power, is less well understood. Because of this, researchers and readers should be aware of the need to address issues of statistical power before a study begins and be cautious of studies that conclude that no difference exists between groups.

Epidemiologic Research Design↗