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Biomedical subjects

Charles Milgrom

Publications and source records attributed to Charles Milgrom.

8 recordsLinked to original sources
PubMed2006

The effect of muscle fatigue on in vivo tibial strains.

Stress fracture is a common musculoskeletal problem affecting athletes and soldiers. Repetitive high bone strains and strain rates are considered to be its etiology. The strain level necessary to cause fatigue failure of bone ex vivo is higher than the strains recorded in humans during vigorous physical activity. We hypothesized that during fatiguing exercises, bone strains may increase and reach levels exceeding those measured in the non-fatigued state. To test this hypothesis, we measured in vivo tibial strains, the maximum gastrocnemius isokinetic torque and ground reaction forces in four subjects before and after two fatiguing levels of exercise: a 2km run and a 30km desert march. Strains were measured using strain-gauged staples inserted percutaneously in the medial aspect of their mid-tibial diaphysis. There was a decrease in the peak gastrocnemius isokinetic torque of all four subjects' post-march as compared to pre-run (p=0.0001), indicating the presence of gastrocnemius muscle fatigue. Tension strains increased 26% post-run (p=0.002, 95 % confidence interval (CI) and 29% post-march (p=0.0002, 95% CI) as compared to the pre-run phase. Tension strain rates increased 13% post-run (p=0.001, 95% CI) and 11% post-march (p=0.009, 95% CI) and the compression strain rates increased 9% post-run (p=0.0004, 95% CI) and 17% post-march (p=0.0001, 95% CI). The fatigue state increases bone strains well above those recorded in rested individuals and may be a major factor in the stress fracture etiology.

Adult↗
PubMed2005

A controlled randomized study of the effect of training with orthoses on the incidence of weight bearing induced back pain among infantry recruits.

STUDY DESIGN: Randomized controlled trial. OBJECTIVES: To determine if the use of custom shoe orthoses can lessen the incidence of weight bearing-induced back pain. SUMMARY OF BACKGROUND DATA: The scientific basis for the use of orthoses to prevent back pain is based principally on studies that show that shoe orthoses can attenuate the shock wave generated at heel strike. The repetitive impulsive loading that occurs because of this shock wave can cause wear of the mechanical structures of the back. Previous randomized studies showed mixed results in preventing back pain, were not blinded, and used orthoses for only short periods of time. METHODS: A total of 404 eligible new infantry recruits without a history of prior back pain were randomly assigned to received either custom soft, semirigid biomechanical, or simple shoe inserts without supportive or shock absorbing qualities. Recruits were reviewed biweekly by an orthopaedist for back signs and symptoms during the course of 14 weeks of basic training RESULTS: The overall incidence of back pain was 14%. By intention-to treat and per-protocol analyses, there was no statistically significant difference between the incidence of either subjective or objective back pain among the 3 treatment groups. Significantly more recruits who received soft custom orthoses finished training in their assigned orthoses (67.5%) than those who received semirigid biomechanical orthoses (45.5%) or simple shoe inserts (48.6%), P = 0.001. CONCLUSIONS: The results of this study do not support the use of orthoses, either custom soft or semirigid biomechanical, as prophylactic treatment for weight bearing-induced back pain. Custom soft orthoses had a higher utilization rate than the semirigid biomechanical or simple shoe inserts. The pretraining physical fitness and sports participation of recruits were not related to the incidence of weight bearing-induced back pain.

Adolescent↗
PubMed2004

The effect of prophylactic treatment with risedronate on stress fracture incidence among infantry recruits.

When subjected to strains or strain rates higher than usual, the bone remodels to repair microdamage and to strengthen itself. During the initial resorption phase of remodeling, the bone is transitorily weakened and microdamage can accumulate leading to stress fracture. To determine whether short-term suppression of bone turnover using bisphosphonates can prevent the initial loss of bone during the remodeling response to high bone strain and strain rates and potentially prevent stress fracture, we conducted a randomized, double-blind, placebo-controlled trial of 324 new infantry recruits known to be at high risk for stress fracture. Recruits were given a loading dose of 30 mg of risedronate or placebo daily for 10 doses during the first 2 weeks of basic training and then a once a week maintenance dose for the following 12 weeks. Recruits were monitored by biweekly orthopedic examinations during 15 weeks of basic training for stress fractures. Bone scans for suspected tibial and femoral stress fractures and radiographs for suspected metatarsal stress fractures were used to verify stress fracture occurrence. By the intention-to-treat analysis and per-protocol analysis, there was no statistically significant difference in the tibial, femoral, metatarsal, or total stress fracture incidence between the treatment group and the placebo. We conclude that prophylactic treatment with risedronate in a training population at high risk for stress fracture using a maintenance dosage for the treatment of osteoporosis does not lower stress fracture risk.

Etidronic Acid↗
PubMed2004

A prospective study of the effect of foot orthoses composition and fabrication on comfort and the incidence of overuse injuries.

BACKGROUND: Foot orthoses are widely prescribed both to treat existing pathological conditions and to prevent overuse injuries, but little is known about the effect of their material composition and fabrication technique on patient comfort and the incidence of overuse injuries. MATERIALS AND METHODS: The acceptance rates and comfort scores of soft custom, soft prefabricated, semirigid biomechanical, and semirigid prefabricated orthoses and their effect on the incidence of stress fractures, ankle sprains, and foot problems were studied in a prospective, randomized, single-blinded clinical trial among 874 infantry recruits during basic training. RESULTS: A statistically significantly lower number of recruits given soft prefabricated orthoses (53%) finished basic training in their assigned devices than in the soft custom group (72%), in the semirigid biomechanical group (75%), and in the semirigid prefabricated group (82%) (p = .003). For recruits who finished training in their assigned orthoses, the soft custom (3.54) and soft prefabricated (3.43) orthoses had significantly higher comfort scores than the semirigid biomechanical (3.23) and prefabricated (3.17) orthoses, (p = .0001). There was no statistically significant difference in the incidence of stress fractures, ankle sprains, or foot problems between recruits using the different types of orthoses. CONCLUSIONS: These findings suggest that if a foot orthosis is being dispensed as prophylaxis for overuse injuries in an active, healthy population, there is little justification for prescribing semirigid biomechanical orthoses. Their cost is high compared to other types of orthoses, without an advantage in comfort or a reduction in stress fractures, ankle sprains, and foot problems.

Adolescent↗
PubMed2003

Do physicians correctly estimate radiation risks from medical imaging?

Proper use of medical imaging tools requires knowledge of their associated radiation risks, as well as their possible benefits. The authors assessed physicians' knowledge of the radiation risks associated with bone scintigraphy (bone scan) during an annual meeting of the Israeli Orthopedic Society. The mortality risk of radiation-induced carcinoma from bone scan was identified correctly by less than 5% of respondents. The most frequent answer (38.4%) was the option that was least correct. Senior orthopedists estimated lower risks than did residents. Overall, respondents grossly underestimated the potential radiation risk from bone scan.

Bone and Bones↗
PubMed2002

Computer-based periaxial rotation measurement for aligning fractured femur fragments from CT: a feasibility study.

A new computer-based method for measuring periaxial rotation of healthy and fractured femurs from preoperative CT during closed femoral fracture reduction surgery is described. The method provides a comparative quantitative measure to align the distal and proximal femur fragments based on periaxial rotation. The periaxial rotation is defined in terms of patient-specific bone features. An algorithm for automatically extracting these features from the CT based on this definition has been developed. The algorithm extracts the condyle landmarks and neck axis of the healthy bone, determines its periaxial rotation, and extrapolates this data, assuming mirror symmetry between the healthy and fractured bones, to measure periaxial rotation between the fractured fragments. Unlike existing techniques, the method requires minimal user intervention. In a feasibility study, the method was applied to five dry femurs and one patient data set, and simulated a reduction based on the periaxial measurements with satisfactory results. The experiments showed the measured angle on the fractured femur to be within 1-4.5 degrees of that of the healthy bone.

Algorithms↗
PubMedDate not supplied

The role of biomechanical shoe orthoses in tibial stress fracture prevention.

BACKGROUND: Biomechanical orthoses have been shown to lower stress fracture incidence in infantry recruits. However, these results may not be applicable to running athletes. HYPOTHESIS: Training in either running shoes or military boots with custom biomechanical shoe orthoses lessens tibial bone strains and strain rates during walking and running. STUDY DESIGN: Randomized controlled laboratory study. METHODS: In vivo strain measurements were made in nine subjects to determine whether the use of biomechanical orthoses lowers tibial strains during both walking and running and whether such lowering depends on the type of shoe worn. Measurements were made during treadmill walking at 5 km/hr and then during serial 2-km treadmill runs at 13 km/hr with running shoes, with and without the orthoses, and during serial 1-km runs with army boots, with and without the orthoses. RESULTS: When soft or semirigid biomechanical orthoses were worn with boots, the tibial peak-to-peak strains were significantly lowered. Soft orthoses also significantly lowered the tension and compression strain rates when worn with boots. During running, semirigid orthoses significantly increased the compression and tension strain rates when worn with boots. CONCLUSIONS: The use of biomechanical orthoses may be warranted for tibial stress fracture prevention during training in which boots are worn and that mostly involves walking, but they are not warranted for activities that primarily involve running or are performed in running shoes.

Adult↗