Biomedical subjects

Stephen Lyman

Publications and source records attributed to Stephen Lyman.

7 recordsLinked to original sources

PubMed2004

Mini-incision for total hip arthroplasty: a prospective, controlled investigation with 5-year follow-up evaluation.

A group of 42 primary total hip arthroplasties performed through an abridged surgical incision (group 1) was prospectively compared to a cohort of 42 primary total hip arthroplasties performed through a standard surgical incision (group 2). The length of the incision was 8.8 +/- 1.5 cm for group 1 and 23.0 +/- 2.1 cm for group 2. The groups were not significantly different with respect to age, height, preoperative Harris Hip scores (HHS), estimated blood loss, or length of hospital stay (P>.05). Group 1 patients had a lower body mass index than group 2 patients (P<.01). Length of surgery was slightly less for group I (P =.02). A 0% incidence was found of infection, nerve palsy, component malposition, and aseptic loosening in both groups. No dislocations occurred in group 1, and one dislocation occurred in group 2. Patients in group 1 have expressed considerable enthusiasm regarding the cosmetic appearance of the surgical incisions, and their postoperative HHS are slightly higher than those of group 2 (P =.042). Total hip arthroplasty can be performed safely and effectively through an abridged surgical incision, but this investigation confirms no dramatic clinical benefit other than cosmetic appeal.

Aged↗

PubMed2003

Occupant deaths in large truck crashes in the United States: 25 years of experience.

There is public concern about the magnitude of the problem of large truck crashes in the US. Fatalities in large truck crashes have not declined much; however, more large trucks are driving more miles than ever before while fatalities per mile driven have dropped substantially. This study examined how the public health burden of large truck crashes versus the risk per unit of travel has changed over 25 years. The present study focused on the US vehicle occupants in fatal crashes involving a large truck during 1975-1999. Occupant fatalities per 100000 population, per 10000 licensed drivers, per 10000 registered trucks and per 100 million vehicle-miles of travel (VMT) were calculated to determine trends in occupant deaths in large truck crashes. In 1999, large truck crashes resulted in 3916 occupant deaths in passenger vehicles and 747 in large trucks. Passenger vehicle occupant deaths in large truck crashes per 100000 population have increased somewhat since 1975 (1.28 in 1975 and 1.44 in 1999). There have been appreciable declines in occupant deaths per truck VMT since 1975, but the percentage reduction has been greater for occupants of large trucks (67%) than for passenger vehicle occupants (43%). However, truck drivers are at elevated risk of dying relative to their numbers in the workforce. Overall large truck involvements in fatal crashes per truck VMT decreased more than passenger vehicle involvements per passenger VMT (PVMT; 68% versus 33% decreases for single-vehicle crashes and 43% versus 23% for multiple-vehicle crashes). Large truck involvement in fatal crashes has dropped substantially when measured per unit of travel, but the public health burden of large truck crashes, as measured by deaths per 100000 population, has not improved over time because of the large increase in truck mileage. Research is needed on measures to better protect both occupants of large trucks and passenger vehicle occupants colliding with them.

Accidents, Traffic↗

PubMed2003

Research methodology.

Research aims to reach valid conclusions through scientific enquiry. Valid conclusions can only be reached if bias is minimized or eliminated. Bias can potentially take place in the design, implementation, or analysis of a study. Various study designs reduce bias, and this article reviews some of the more common study designs in orthopaedic sports medicine. We also discuss bias and confounding factors as they relate to these studies.

Bias↗

PubMed2003

Accuracy of qualitative analysis for assessment of skilled baseball pitching technique.

Baseball pitching must be performed with correct technique if injuries are to be avoided and performance maximized. High-speed video analysis is accepted as the most accurate and objective method for evaluation of baseball pitching mechanics. The aim of this research was to develop an equivalent qualitative analysis method for use with standard video equipment. A qualitative analysis protocol (QAP) was developed for 24 kinematic variables identified as important to pitching performance. Twenty male baseball pitchers were videotaped using 60 Hz camcorders, and their technique evaluated using the QAP, by two independent raters. Each pitcher was also assessed using a 6-camera 200 Hz Motion Analysis system (MAS). Four QAP variables (22%) showed significant similarity with MAS results. Inter-rater reliability showed agreement on 33% of QAP variables. It was concluded that a complete and accurate profile of an athlete's pitching mechanics cannot be made using the QAP in its current form, but it is possible such simple forms of biomechanical analysis could yield accurate results before 3-D methods become obligatory.

Adolescent↗

PubMed2002

Heel pain triad (HPT): the combination of plantar fasciitis, posterior tibial tendon dysfunction and tarsal tunnel syndrome.

Between 1996 and 1999, we evaluated 286 patients with chronic heel pain. We identified 14 patients who were diagnosed and surgically treated for a unique combination of plantar fasciitis, posterior tibial tendon dysfunction and tarsal tunnel syndrome. We postulate that failure of the static (plantar fascia) and dynamic (posterior tibial tendon) support of the longitudinal arch of the foot has resulted in traction injury to the posterior tibial nerve, i.e., tarsal tunnel syndrome. The combination of plantar fasciitis, posterior tibial tendon dysfunction and tarsal tunnel syndrome was recognized and treated. We have called this combination the "Heel Pain Triad (HPT)." Using the AOFAS hindfoot rating system, retrospective chart review and patient examination revealed marked improvement in 85.7% of patients. Follow-up was done four to 33 months (mean follow-up was 17.1 months). Marked improvement was noted in the categories of pain, activity level, walking distance, walking surface and limp. Improvement was statistically significant for all categories.

Adult↗

PubMedDate not supplied

Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers.

The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint range of motion and laxity along with humeral head and glenoid version of the dominant versus nondominant shoulders were studied in 25 professional pitchers and 25 nonthrowing subjects. Each subject underwent a computed tomography scan to determine bilateral humeral head and glenoid version. The throwing group demonstrated a significant increase in the dominant shoulder versus the nondominant shoulder in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees, and external rotation in the scapular plane. Internal rotation was decreased in the dominant shoulder. Total range of motion, anterior glenohumeral laxity, and posterior glenohumeral laxity were found to be equal bilaterally. The nonthrowing group demonstrated no significant difference in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90 degrees, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90 degrees and humeral head retroversion were significantly greater in the throwing group.

Adaptation, Physiological↗

PubMedDate not supplied

Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers.

BACKGROUND: Joint pain is thought to be an early sign of injury to a pitcher. OBJECTIVE: To evaluate the association between pitch counts, pitch types, and pitching mechanics and shoulder and elbow pain in young pitchers. STUDY DESIGN: Prospective cohort study. METHODS: Four hundred and seventy-six young (ages 9 to 14 years) baseball pitchers were followed for one season. Data were collected from pre- and postseason questionnaires, injury and performance interviews after each game, pitch count logs, and video analysis of pitching mechanics. Generalized estimating equations and logistic regression analysis were used. RESULTS: Half of the subjects experienced elbow or shoulder pain during the season. The curveball was associated with a 52% increased risk of shoulder pain and the slider was associated with an 86% increased risk of elbow pain. There was a significant association between the number of pitches thrown in a game and during the season and the rate of elbow pain and shoulder pain. CONCLUSIONS: Pitchers in this age group should be cautioned about throwing breaking pitches (curveballs and sliders) because of the increased risk of elbow and shoulder pain. Limitations on pitches thrown in a game and in a season can also reduce the risk of pain. Further evaluation of pain and pitching mechanics is necessary.

Adolescent↗