Biomedical subjects
Publications and source records attributed to Kevin B Freedman.
Several techniques exist to increase the rate of healing of meniscal tears after repair. We describe a simple arthroscopic technique of microfracture to the intercondylar notch. This technique can provide marrow elements to the site of meniscus repair to aid in meniscal healing at the time of repair.
The clinical results after high tibial osteotomy for the treatment of symptomatic varus gonarthrosis are unpredictable. Although preoperative gait analysis has been shown to be useful in predicting successful outcome after high tibial osteotomy, there are no readily available preoperative clinical tests for predicting success. The authors did a study to determine the effects of an offset short-leg walking cast as a potential predictor of clinical success after high tibial osteotomy. Specifically, the authors evaluated the effect of an offset short-leg walking cast on pain relief and changes in the peak external adduction moments in patients with symptomatic varus gonarthrosis indicated for high tibial osteotomy. Nineteen consecutive patients indicated for high tibial osteotomy were enrolled and completed the study. All patients had precast gait analysis to determine baseline parameters. Immediately after gait analysis, a short-leg lateral offset walking cast was applied and worn for 3 days to allow time for adaptation. Gait analysis then was repeated. Western Ontario and McMaster Universities Osteoarthritis Index pain scores were obtained before and after the cast was applied. The cast resulted in a mean reduction in pain of 53%, and a mean reduction in the peak external adduction moment of 36% in the 17 of 19 patients who tolerated the cast. The reduction in pain was correlated with the reduction in the peak adduction moment (r = 0.63). The authors conclude that an offset short-leg walking cast results in pain reduction that correlates with changes in external adduction moments about the knee. Therefore, an offset short-leg walking cast may prove to be an effective tool for predicting patients who ultimately will benefit from valgus high tibial osteotomy.
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.
BACKGROUND: We previously reported the results of a study in which a basic competency examination in musculoskeletal medicine was administered to a group of recent medical school graduates. This examination was validated by 124 orthopaedic program directors, and a passing grade of 73.1% was established. According to that criterion, 82% of the examinees failed to demonstrate basic competency in musculoskeletal medicine. It was suggested that perhaps a different passing grade would have been set by program directors of internal medicine departments. To test that hypothesis, and to determine whether the importance of the individual questions would be rated similarly, the validation process was repeated with program directors of internal medicine residency departments as subjects. METHODS: Our basic competency examination was sent to all 417 program directors of internal medicine departments in the United States. Each recipient was mailed a letter of introduction explaining the purpose of the study, a copy of the examination, and our answer key and scoring guide. There was no mention of the results of the first study. The subjects were requested to rate the importance of each question on the same visual analog scale, ranging from "not important" to "very important," as had been used by the orthopaedic program directors. These ratings were converted into numerical scores. The program directors were also asked to suggest a passing score for the examination, and this score was used to assess the examinees' performance on the examination. The results on the basis of the internal medicine program directors' responses and those according to the orthopaedic program directors' responses were compared. RESULTS: Two hundred and forty (58%) of the 417 program directors of internal medicine residency departments responded. They suggested a mean passing score (and standard deviation) of 70.0% +/- 9.9%. As reported previously, the mean test score of the eighty-five examinees was 59.6%. Sixty-six (78%) of them failed to demonstrate basic competency on the examination according to the criterion set by the internal medicine program directors. The internal medicine program directors assigned a mean importance score of 7.4 (of 10) to the questions on the examination compared with a mean score of 7.0 assigned by the orthopaedic program directors. The internal medicine program directors gave twenty-four of the twenty-five questions an importance score of at least 5 and seventeen of the twenty-five questions an importance score of at least 6.6. CONCLUSIONS: According to the standard suggested by the program directors of internal medicine residency departments, a large majority of the examinees once again failed to demonstrate basic competency in musculoskeletal medicine on the examination. It is therefore reasonable to conclude that medical school preparation in musculoskeletal medicine is inadequate.
BACKGROUND: The best choice of graft tissue for use in anterior cruciate ligament reconstruction has been the subject of debate. HYPOTHESIS: Anterior cruciate ligament reconstruction with patellar tendon autograft leads to greater knee stability than reconstruction with hamstring tendon autograft. STUDY DESIGN: Metaanalysis. METHODS: A Medline search identified articles published from January 1966 to May 2000 describing arthroscopic anterior cruciate ligament reconstruction with either patellar tendon or hamstring tendon autograft and with a minimum patient follow-up of 24 months. RESULTS: There were 1348 patients in the patellar tendon group (21 studies) and 628 patients in the hamstring tendon group (13 studies). The rate of graft failure in the patellar tendon group was significantly lower (1.9% versus 4.9%) and a significantly higher proportion of patients in the patellar tendon group had a side-to-side difference of less than 3 mm on KT-1000 arthrometer testing than in the hamstring tendon group (79% versus 73.8%). There was a higher rate of manipulation under anesthesia or lysis of adhesions (6.3% versus 3.3%) and of anterior knee pain in the patellar tendon group (17.4% versus 11.5%) and a higher incidence of hardware removal in the hamstring tendon group (5.5% versus 3.1%). CONCLUSIONS: Patellar tendon autografts had a significantly lower rate of graft failure and resulted in better static knee stability and increased patient satisfaction compared with hamstring tendon autografts. However, patellar tendon autograft reconstructions resulted in an increased rate of anterior knee pain.
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