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Biomedical subjects

Kevin B Freedman

Publications and source records attributed to Kevin B Freedman.

15 recordsLinked to original sources
PubMed2006

Biomechanics of coracoacromial arch modification.

Although the biomechanics of the coracoacromial arch and coracoacromial ligament (CAL) morphology are well studied, to our knowledge, the biomechanics of the coracoacromial arch after CAL resection and medial reattachment have not yet been studied. The purpose of this report is to examine the biomechanical consequences of coracoacromial arch alteration and subsequent reconstruction in cadaveric specimens. Anterosuperior humeral head translation was measured after the application of an anterosuperior 150-N load under 5 sequential scenarios: (1) intact CAL, (2) subperiosteal CAL release, (3) standard acromioplasty, (4) CAL reconstruction, and (5) modified Neer acromioplasty. A significant decrease in anterosuperior migration was found after CAL reconstruction compared with both anterior acromioplasty (P = .038) and modified Neer acromioplasty (P = .01). Thus, in patients with massive rotator cuff tears, reconstruction of the CAL may provide the necessary stabilizing force to prevent excessive anterosuperior translation and possible humeral head escape from the coracoacromial arch.

Acromion↗
PubMed2006

The effect of corticosteroid on collagen expression in injured rotator cuff tendon.

BACKGROUND: Subacromial corticosteroid injections are commonly used in the nonoperative management of rotator cuff disease. The effects of corticosteroid injection on injured rotator cuff tendons have not been studied. Our aims were to characterize the acute response of rotator cuff tendons to injury through the analysis of the type-III to type-I collagen expression ratio, a tendon injury marker, and to examine the effects of corticosteroid on this response. METHODS: Sixty Sprague-Dawley rats were randomly assigned to four groups: control, tendon injury, steroid treatment, and tendon injury and steroid treatment. Six rats served as sham controls. Unilateral tendon injuries were created with full-thickness defects across 50% of the total width of the infraspinatus tendon, 5 mm from its humeral insertion. Steroid treatment with a single dose of methylprednisolone (0.6 mg/kg), equivalent to that given to humans, was injected into the subacromial space under direct visualization. Steroid treatment followed the creation of an injury in the rats in the injury and steroid treatment group. At one, three, and five weeks after the injury, the total RNA isolated from tendons was quantified with real-time polymerase chain reaction with use of primers for type-I and type-III collagen and ribosomal 18s RNA. RESULTS: The type-III to type-I collagen expression ratio remained at baseline at all time-points in the control and sham groups. At one week, the type-III to type-I collagen expression ratio increased more than fourfold above the control level in the tendon injury group (p = 0.017) and the tendon injury and steroid treatment group (p = 0.003). The ratio remained greater than twofold above the control at three weeks in both groups (p = 0.003 and p = 0.037) and returned to baseline at five weeks. Interestingly, the group that had steroid treatment only showed an increase of >4.5-fold (p = 0.001) in the type-III to type-I collagen expression ratio, without structural injury to the tendon. This ratio returned to baseline levels by three weeks. CONCLUSIONS: A single dose of corticosteroid does not alter the acute phase response of an injured rotator cuff tendon in the rat. However, the same steroid dose in uninjured tendons initiates a short-term response equivalent to that of structural injury.

Animals↗
PubMed2005

Thermal modification of partial tears of the anterior cruciate ligament.

PURPOSE: Partial tears of the anterior cruciate ligament (ACL) are common, representing 10% to 28% of all ACL tears. Untreated partial tears of the ACL may go on to complete rupture in up to 42% of cases, and as few as 30% of patients return to their preinjury activity level. The purpose of this study was to evaluate the effectiveness of thermal modification for the treatment of partial tears of the ACL. TYPE OF STUDY: A prospective, nonrandomized consecutive case series. METHODS: Thirteen patients with a partial tear of a native ACL were treated with thermal modification of the ACL. All patients had a preoperative office examination significant for an end-point to Lachman examination and pivot-glide. All patients had bilateral preoperative KT-1000 measurements. All tears were confirmed by arthroscopy to constitute a 50% or less loss of structural integrity of the ligament. The ACL underwent thermal modification using the Oratec thermal probe (Oratec Interventions, Menlo Park, CA), and was examined by intraoperative KT-1000 testing. Patients were evaluated postoperatively at 6 weeks, and at 3, 6, 12, and 24 months by office examination and functional outcome scoring. RESULTS: KT-1000 arthrometer testing revealed a mean side-to-side difference of 4.35 mm preoperatively (SD = 1.1 mm). At the most recent follow-up, averaging 23 months (range, 18 to 28 months), 10 patients had a negative Lachman examination and no pivot-shift. Two patients had persistent grade II Lachman and complaints of giving way 3 months postoperative. Both patients underwent ACL reconstruction. One patient was lost to follow-up. Of the remaining 10 patients, all patients achieved full extension, and the average flexion range of motion was 131 degrees (SD = 5.6). Compared with the preoperative KT-1000 arthrometer testing, the most recent evaluation revealed a decrease in mean side-to-side difference to 1.9 mm (SD = 1.5 mm). At most recent follow-up, the mean Lysholm score was 96.3 (SD = 4.4), the mean Tegner score was 6.1 (SD = 1.2), and the mean Cincinnati score was 94 (SD = 3.0). CONCLUSIONS: With cautious application, thermal modification may be a viable treatment option for partial tears of the ACL in a select subset of patients. Further investigation is necessary to determine the long-term effectiveness of this procedure. LEVEL OF EVIDENCE: Level IV, Therapeutic Case Series Study (no or historical control group).

Adult↗
PubMed2005

The effect of radiofrequency energy on nonweight-bearing areas of bone following shoulder and knee arthroscopy.

This prospective randomized clinical trial evaluated whether the use of radiofrequency energy (RFE) devices for soft-tissue ablation and coagulation cause thermal injury to bone. Fifty patients underwent one of three treatment modalities: electrocautery, monopolar RFE, or bipolar RFE. Preoperative and postoperative magnetic resonance imaging was compared to evaluate for evidence of osteonecrosis. Postoperative MRI of all patients did not reveal any osteonecrosis or subchondral edema. These findings indicate electrocautery, monopolar RFE, and bipolar RFE devices can be used safely for soft-tissue blation and hemostasis.

Acromion↗
PubMed2005

Revision reconstruction of the anterior cruciate ligament: evaluation and management.

Primary reconstruction of the anterior cruciate ligament (ACL) restores knee stability in up to 95% of patients, but instability can recur. Identifying the cause of primary reconstruction failure is the most important action to be taken when considering revision reconstruction. Preoperative evaluation and planning are essential before revision ACL reconstruction. In this article, we review causes of failure, considerations for preoperative evaluation and planning, and techniques for revision and provide an overview of the results of revision reconstruction.

Anterior Cruciate Ligament↗
PubMed2004

Open Bankart repair versus arthroscopic repair with transglenoid sutures or bioabsorbable tacks for Recurrent Anterior instability of the shoulder: a meta-analysis.

BACKGROUND: In published comparative studies, it remains unknown if arthroscopic techniques for performing Bankart repair for anterior shoulder instability equal the success of open repair. HYPOTHESIS: The current literature supports a lower rate of recurrent instability after open Bankart repair compared to arthroscopic repair with bioabsorbable tacks or transglenoid sutures. STUDY DESIGN: Meta-analysis. METHODS: A Medline search identified all randomized controlled trials or cohort studies that directly compared open repair to arthroscopic techniques of Bankart repair for traumatic, unilateral, recurrent anterior instability. Data collected from each study included patient demographics, surgical technique, rehabilitation, outcome, and complications. RESULTS: Six studies met all inclusion criteria. There were 172 patients in the arthroscopic group (90 patients with transglenoid sutures, 77 patients with arthroscopic tacks, and 5 patients with suture anchors) and 156 patients in the open group. The groups were similar in demographic characteristics. When comparing the arthroscopic to the open group, there was a significantly higher rate of recurrent dislocation (12.6% vs 3.4%; P = .01) and total recurrence (recurrent dislocation or subluxation) (20.3% vs 10.3%; P = .01). In addition, there was a higher proportion of patients with an excellent or good postoperative Rowe score in the open group (88%) than in the arthroscopic group (71%) (P = .01). CONCLUSIONS: Arthroscopic Bankart repair using transglenoid sutures or bioabsorbable tacks results in a higher rate of recurrence of instability compared to open techniques. Studies comparing open repair to newer arthroscopic techniques using suture anchor fixation and capsular plication are necessary.

Absorbable Implants↗
PubMed2004

Knee dislocations: management of the multiligament-injured knee.

Knee dislocations can occur in low-energy athletic injuries and in high-velocity motor vehicle trauma. These injuries require urgent recognition for evaluation for neurovascular injury. Advances in surgical reconstruction of multiligament-injured knees have led to more predictable return of function. This article reviews the diagnosis, initial treatment, and definitive management of multiligament-injured knees.

Anterior Cruciate Ligament Injuries↗
PubMed2003

Marrow stimulating technique to augment meniscus repair.

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.

Arthroscopy↗
PubMed2003

Use of a lateral offset short-leg walking cast before high tibial osteotomy.

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.

Adult↗
PubMed2003

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↗
PubMed2002

Educational deficiencies in musculoskeletal medicine.

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.

Education, Medical, Graduate↗
PubMedDate not supplied

Arthroscopic anterior cruciate ligament reconstruction: a metaanalysis comparing patellar tendon and hamstring tendon autografts.

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.

Adult↗