Orthopedic Biomechanics - Science topic

Born with club feet which were corrected by means of plastering within the 6 months of age. Current age 67 years. Suffering feet and ankle pain for over 3.5 decades. Habitual of a routine post dinner walk for about 3-4 km everyday. No pain killers used. Pain is normally bearable but sometimes gets severe and is normally relieved to bearable limits by warm water bath / contrast bath. Recent podiatric/orthotic investigation suggesting Charcot Feet.

There are contradictory recommendations in this regard. Any authentic guidelines please?

Does the term "contrast bath" imply any random time-temperature combination of hot and cold water or it is a specific combination of repetitive alternate spells of dipping the affected body part in cold water at a specific temperature for a specified duration followed by dipping in hot water at a specific temperature for a specified duration?

After the ORIF surgery of right hand wrist fracture, the fingers are stiffened - the finger segments getting as hard as stones (hardened edema) - making the bending of fingers to close the palm as fist almost impossible as the stone hard lower segment of the finger doesn't allow the finger to be bent downwards. The physiotherapist tries mobiisation applying his full might to bend the fingers downwards causing extreme pain to the patient, still the fingers do not bend beyond 90 degrees from their fully stretched position. Is this physiontherapy (extreme torture to the patient) - extending to 2 / 3 / 4 weeks or even more - the only way to restore the fingure movement or there are some easier / painless patient-friendly ways (such as some medication etc.) of treating the stiffened fingers without subjecting the patient to ubearable tortures?

Biomechanics face grand challenges due to the intricacy of living things. We need multidiciplinary approach (mechanical, chemical, electrical, and thermal ) to unravel these intricacies. We need to integrate observations from multiple length scales - from organ level to, tissue level, cell level, molecular level, atomic level, and then to energy level) Over these intricacies, their dynamism, the complexity of their response makes it very difficult to correlate empirical data with theoretical models. Among these challenges, which is the most important challenge. If we solve the most important challenge, we could solve most of the other challenges easily.

Thanks for the answers...

Joint pain is a very common problem with many possible causes - but it's usually a result of injury or arthritis.

Due to the fact that anxiety can increase long term stress, the risk of of inflammation is high. I think This inflammation can cause pain and swelling in joints, affecting every day movements.

I am searching about PEEK cage and I need references for all aspects of mechanical design or test about it.I wanna know more about optimization factors for this device.

How can i determine the upper limit of storage temperature for metal implants, UHMWPE implants with or without crosslinked structure? During packaging, storage, transportation etc. the temperature changes in a wide range. When i look at the raw material standards (ISO 5832-1, 5832-3 etc.) or the general specification standards of nonactive surgical implants (ISO 14630, ISO 21534 etc.) and specific standards of surgical implants (ISO 21535, ASTM F1378 etc.), i cannot see any ideal temperature condition statements. How can i verify the upper temperature for at least storage stage?

Bone fracture is the most common effect in osteoporosis. one the reason is the impact of osteoporosis on the density of the cortical bone. So I'm looking for the role of the density disorder which is caused by osteoporosis in bone fracture.

It's clear, osteoporosis has a direct impact on bone density. How can I figure out the manner of this effect in spongy and cortical bone, separately?

On the other hand, I'd check out how this effect of osteoporosis changes the orientation of bone blades?

Most of the amputees are suffering from the secondary disorders which are more common in upper extremity one. There is more pressure on upper limb amputees’ intact hand since they have to do every single task just by one hand and this imbalance causes musculoskeletal problems such as scoliosis. Despite doctors advice, due to the difficulties of prosthetic hands uses especially in above elbow cases, some of the amputees desist from using it, after a while. I want to know if cosmetic prosthetic really prevents spine deformity like scoliosis?

Knee locking refers to when the leg gets stuck in one position, making it impossible to bend or straighten it. It may only last a few seconds, it may last longer. It all depends on what is causing it. Most cases fall into one of two categories.

There is true locking caused by a mechanical block where something gets stuck inside the joint, preventing movement. This type most commonly occurs as you move the knee into full extension, i.e. towards being fully straight.

Secondly, there is pseudo locking, caused by severe pain which temporarily limits movement in any direction.

In simple fractures it's better to put the screws away from the fracture site to have enough elasticity but in crushed fractures or long ones, screws can be placed near the fracture site to reduce implant tension in the area. What causes this tension?

In what situation which one is better and totally can we say which one is better?

A short femoral stem is a desirable hip implant for bone and soft tissue preserving hip replacing surgery in young arthritic patients. Physiological loading of the proximal femur prevents stress shielding and preserves bone stock of the femur in the long run. Since

the life service of hip prosthesis is less than the longevity of young patient and they 'll need to revision total hip replacement , the short stem prosthesis is better for them.

But are there any another advantages for short stem over standard stem?

And whether do they cause the standard stem will be useless?

A short femoral stem is a desirable hip implant for bone and soft tissue preserving hip replacing surgery in young arthritic patients. Physiological loading of the proximal femur prevents stress shielding and preserves bone stock of the femur in the long run.

Since the life service of hip prosthesis is less than the longevity of young patient and they 'll need to revision total hip replacement , the short stem prosthesis is better for them.

But are there any another advantages for short stem over standard stem?

And whether do they cause the standard stem will be useless?

I really need useful sources to differ these things and answer to this question which way is better.

I really need some sources to describe this obviously .

What mechanical stimulation should have biomechanical properties for severe fractures to have a positive effect?

In leg amputation the remained bone is rasped to make the edges smoother to avoid tissue injuries. but still there is an unusual structure underneath the skin. 

Why don’t we use an implantable structure to avoid abnormal structure like sharp edges and damp the undue pressure and shocks underneath bones, the same way heel fat pad*(HFP) protects the underlying structures in the heel?

From my point of view, using such implants might also ease the use of prosthetic legs and decrease the possible pain in leg- prosthetic interfaces.

Are there any specific reasons not to use such implants during the leg amputation?

*The heel fat pad (HFP) is a highly specialized adipose-based structure that protects the rear foot and the lower extremities from the stress generated during the heel-strike and the initial support phase of locomotion. HFP cushioning efficiency is the result of its structure, shape and thickness.

there are mobile bearing vs fixed bearing, cruciate retaing, PCL retaining, posterior stabilized, medial pivot prosthesis and etc. Companies including Zimmer, Stryker, Microport (Wright) and etc. Which one do you think is better and what are the reasons?

Most health disparity and joint replacement (knee, hip) I've seen look mainly at African-American and Non-Hispanic Whites.  Anyone aware of papers or researchers looking at Asian-Americans?

Thank you!

I want to calculate the maximum tendon stiffness. I know that it corresponds to the slope of the force-length curve in the linear region. However, the limits of linear region are a little subjective. So, which method do you suggest me to set objectively this linear region?

I read a method where the authors defined the linear region "...as the one in which the least-squares-fitted line had the correlation coefficient value of 0.98" (Link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2907260/#R5) but in this method there is a lack of objectivity too. I was thinking in define some percentages as 25 - 75% of maximum force and calculate the stiffness there, but i didn't found researches that support this.

Thank you!

Pd: Sorry for my english, i'm trying to improve it!

I thank colleagues for their suggestions. In annex x-ray images, clinical did not seem to be a problem of rotation. Our decision not to operate because of the fear of possible postoperative .. .prolonged the same legs works of accelerated growth, and at the same time we are not sure that our decision is correct

best regards, 

Can you please suggest plan of management for 2 months old polytrauma in 18 year old morbidly obese lady, who sustained a complex pelvic # with bilateral feet drop? Should we try to salvage this hip with an attempt at ORIF or do a primary THR?

We are analyzing the walking behavior and wanted to know the forces required while doing regular jobs. I know that these data is quite complicated and varies from person to person. However, there will be a simpler way to analyze such forces.

It would be of a great help if you can help us out.

What's the name of distal phalanx pseudarthrosis, due to interposition of ungueal matrix?

I am trying to develop a  new test rig to measure mechanical changes in natural cartilage (glenoid) against humeral cup with different material. I have read a a lot of papers but they work on implant on implant or reverse shoulder arthroplasty. Do you know any groups that might do similar work to my project? 

Thank you! 

I',m attending to a study about the effect of the Cunningham technique for shoulder dislocation, but I need more relevant referrences. Please contact me if you have any full texts of them. Thanks a lot!!!

I've been reading through the literature to create a biomechanical model of counterforce brace effects.  Right now I'm working on the Jumper's Knee strap, and I'm not finding a lot of biomechanical evidence for symptom relief, only a lot of anecdotal clinical accounts.  I was wondering if anyone has published a paper or read a study with more concrete evidence.  This is a little different than the load/force redistribution effect of the tennis elbow counterforce strap...

Does vascularised fibula achieve significantly better union rates than non vascularised fibula for segmental bone defect?

Dear Respected Researchers,

Analysis of Structural Interactions between bone and bone screws.

I have generated the screw model and imported it to design modeler where I created the bone model and used boolean subtraction to create the screw imprint/threads inside the bone. On getting to the Set-up, the contact elements or connection is solid-to-solid and which gave me excessive stress Von-Mises stresses after running the simulation. I have tried to  change it surface-to-surface, rigid-to-flexible contact elements on ANSYS Workbench but to no avail. THANK YOU!

Hello

I would like to test the hip flexors and extensors isometric strength in supine position using the Biodex System 4. These are my options:

1. Set the starting position at 45 degrees so I can test both muscle groups simultaneously. This may give me optimal performance of both muscle groups.

2. Test the hip flexors at 0 degrees and the hip extensors at 90 degrees of hip flexion as a starting position. 

Which position is best? If you have other suggestions kindly let me know.

Thank you

Mohamed

Recently, we had a case of 21yo woman with severe hallux valgus and flatfoot. We tried Lapidus procedure (TMT I arthrodesis and lateral release WITHOUT intermetatarsal stabilisation) and subcapital chevron derotational osteotomy for DMAA correction. Due to traction of the EHL effect was stil unsatisfactory. We decided to add the Akin procedure in the proximal phalanx as a "last hope" procedure. Cosmetic effect seems good. Do you have any experience with this method or do you do try anything different in such cases?

Many surgeon recommend single bundle due to the easiness of the tech. and to avoid weakening of the patella, on the other hand double bundle i see it more close to normal bio-mechanics?  

There are still controversial opinions. What is your experience ? What combination wears less and slowly ? 

Does anyone know if there is a difference with elbow extension torque or force production with a pronated vs. supinated forearm?  Does scapular position make a difference?  When trying to isolate triceps folks will often hold the arm in adduction (dips, cable pushdowns, etc.)  Is this just a perceived benefit or is there objective data supporting?

I need to know what is the taper(conical) angle in pedicle screw of vertebra.

Traditionally the patella fracture with intact extensor apparatus has been treated by cylinder cast, long knee immobilizer brace as well as percutaneous lag screw. 

But is there any evidence in the literature as to what is the best mode of treatment?

I am looking into whether a mathematical model of the hip joint exists to determine contact area to allow me to calculate hip joint stress. Models exist for the patellofemoral joint, is anyone aware of models that are available for the hip.

I know that a large proportion of the muscles in the body are active for a person during her/his gait. But I'm not sure exactly (or approximately) the value of the proportion in percentages with a valid reference.

Man of 58 years-old with trauma (D12 vertebral fracture, fractured left shoulder blade, multiple rib fractures on the left). The scapular fracture treated with immobilization for 30 days (orthopedic). The patient has undergone neurosurgery of reduction / stabilization of the fracture with screws transpedicular D12 D11-D12 L1e kyphoplasty (duration surgery - 1 hour and 25 minutes, anesthesia duration - 2 hours and 15 minutes). The patient was placed in the prone position with the head resting on blankets and turned to the left. Immediately after the operation, during arousal, the patient experienced pain in the left eye, edema and amaurosis. He underwent angiography which showed signs of retinopathy in both eyes and a central retinal artery occlusion in the left eye (CRAO).The patient is diabetic with insulin pump therapy, hyperlipidemic (rosuvastatina), hypertension, occasional smoker or former smoker, hyperhomocysteinemia, assumes Cardioaspirin. The doppler has revealed a thickening of the left carotid artery with a fibro-calcific plaque without significant impairment of flow. In addition, both the CT that the brain MRI showed multiple small areas of gliosis of the white matter, as from vascular cerebral disease. According to your experience, could the prone position to have been the only cause of ocular damage? 

There may be altered joint arthrokinematics and other mechanical issue of an adjacent structure, which may contribute to lateral knee pain. So, what will be the best physiotherapy management?

It is known that Hippocrates had developed a "surgical" technique to stabilise the commonly presented anterior dislocation of the shoulder. In the modern medical era we have developed and abandoned many procedures. Which of them do you think imitates the original Hippocratic technique?

I am doing finite element analysis of knee joint.I have considered the contact between meniscus and femoral/tibial  cartilage to be no separation (with finite sliding) in ANSYS workbench .

For what reason and benefit would someone train legs in isolation from one another, what effects & improvements would be seen and what advantages are found?

Suggestions of, Medical journals &/or technical papers on movement/function/mechanics/positions of the body would be welcome.  

I am doing Finite element analysis of knee joint to investigate the effects of meniscectomies on  knee biomechanics

A patient had been subjected for ORIF for  supracondylar  fracture distal femur 5 months earlier, he is presenting with stiff knee to 30 degrees flexion and with no active quadriceps contraction.

A new development in both TSA and RSA have been convertible stems; in both applications, the same humeral stem is used. Newer designs allow the same stem for total, reverse, and fracture cases (previously, a separate stem was needed for total and fracture for conversion to reverse). Since the neck-shaft angle is more varus for primary or fracture applications, this affects the position when converted to reverse.

Boileau et al reported that since convertible systems require an onlay humeral cup as opposed to an inlay humeral cup used in Grammont-style prosthesis, this led to humeral lateralization.

My question then is are there any convertible shoulder designs that avoid humeral lateralization?

Diagnostic criteria for upper cross syndrome?

Does anyone know if there is consensus in this topic?

patients presented with severe pain in their fingers after wearing rings of different metals for along period .the pain increased with movement . no allergy from metals. the joint movement is restricted slightly.

Hi all! as a part of a study about the Ponseti procedure for the treatment of the congenital clubfoot  I’m analyzing the correlation between two different scores (Pirani and Dimeglio) and the number of casts required to achieve the correction. I used Spearman rho (normality could not be assumed as the K-S test indicated the p-value of less than .05 for all the items) and found that  both Pirani and Dimeglio are significantly associated to the number of casts, and almost collinear between them (Spearman’s rho = .875); but how to determine which is better in terms of predictability? May I use linear regression or what else? Thank you all for your suggestion

I am a physical therapist who specializes in the treatment of facial palsy and TMD.  We are finding a very high incident of those patients that are slow to recover have as preexisting condition of TMD.  Looking for collaborators to investigate the mechanism of the link.

- Are there different risk factors for each one?

- Why some people have one or the other lesion?

- What are the main etiological differences?

We know that after hip surgery some parts of the artificial joint is separated because of the load pressure and immune defense cells  secrete toxic substances to destroy foreign bodies .this  material absorbs most of the bones in the place of joint and weakens the connection .it causes the second surgery.so how can we reduce it?

Application: athletic tape

Preferred fabric: cotton or cotton blend

In hip replacement surgery orthopedic surgeon inner surface of the acetabular cavity in the pelvic area that has been corrupted to make a full hemisphere. A hemisphere-shaped metal bowl placed inside the cavity. Inside the metal bowl placed a polyethylene plastic bowl. Sometimes plastic bowl without metal bowl attached into the acetabulum cavity by bone cement .

In some cases it has been observed that after a few months or a few years, polyethylene is causing loosening of the artificial joint and bone fractures.

We want to know how the bone fracture affects polyethylene.

In the study of intervertebral disc degeneration, many animal models are being used to mimic human disc degeneration. However, the degeneration in these models is generally induced by directly damaging the intervertebral disc structure or applying high mechanical forces. These methods can't cause endplate calcification, which paly an important role in human disc degeneration. Is there any aged animal model that could develop endplate calcification in intervertebral disc? (Besides the shot tail rat) Or any technology can induce endplate calcification in commonly aviliable animals?

I am interested in obtaining physiological loading and boundary conditions applied on the femur, especially during walking activity. I read some papers saying that femoral head deflects towards the knee joint center. I need to verify if this information is 100 % correct or if it is just coming from common sense. Appropriate references would be great.

Thanks.

It looks like that this pathology seems misdiagnosed and mistreated in some countries all other the world. Nevertheless, the responsibility of this structure seems well established and, as far as I know, there is no doubt about it's responsibility for severe anterior knee pain, osteomalacy, osteochondritis or severe impingement.

What is your feeling about it and which therapeutic options are yours for these specific pathological situations: fast and easy arthroscopy or conservative treatment?

I am looking for the actual forces required to cause fractures to the various different regions of the facial and skull bones.  If you could share some info/ literature on that would be of great help (either general or specific to motor vehicle accidents).

In a few cases I had to... Mostly for cases with severe PRE-OP lateral tibial plateau instability with relevant positive JERK test, in order to avoid POST-OP PL instability as well as to protect my transplant. Somme of our Colleagues systematically associate this technique to their IA surgery. What is your experience about it and which technique do you use for it?

I would need a good reference form literature, from which to get a clear description and motivation of how to calculate hip range of motion in swing and maximal/minimal hip flexion.

Does anyone have experience in treatment of hip luxation in konradi syndrome?

Hello dear researchers... I need to learn specific values of tendon excursion and resting tonuses of Extensor carpi ulnaris, Extensor carpi radials longus and brevis, extensor digitorum communis, extensor pollicis longus and abductor pollicis longus tendons. proximal to the wrist. It'll be highly appreciated if the data is provided along with their flexor counterparts.

I want to create a finite element model of the thoracic spine. After looking at the literature, I realized that some detailed (in terms of muscle complexity, attachment sites, etc.) lumbar and cervical spine models exist, but thoracic spine is not somehow (although a few studies look at the thoracolumbar spine). I will be thankful if you suggest me where I shall begin, and direct me to studies from where I can get data regarding muscle anatomy acting on the thoracic spine with their attachment locations.

Regards.

I am looking for collecting health survey scores for Orthopaedic patients in UK via SF12. I got both SF12 V1 and SF12 V2. It looks like SF12V2 is better to use.

In some patients we observe an oblique joint line (i.e. in cases of a femoral valgus which is compensated by a tibial varus deformity) even though the overall alignment of the affected leg is straight. Does anybody know papers on the biomechanical influence of an oblique joint line in such patients ?

Assuming the human body to be in static state (Standing), what amount of the body weight is transmitted on to the femoral and tibial bone on both the legs? Will both the legs carry equal weight or is there unequal distribution of weight on the left and right leg? 

Dear colleagues,

I am planning a dissection study to measure attachment sites of back muscles in the spine. For every muscle, I will measure its coordinates of origin and insertion on the vertebrae, pelvis and ribs in space. The problem is that during the measurements vertebrae and ribs may move and that could change the positions of attachments and, in turn, muscle line of action. The first thing I thought was to connect vertebrae together by using metal plates and screws so that they do not move with respect to each other. I am wondering if there is a better way, and would like to kindly ask your advice on that.

Kind regards,

Riza.

i have done study on effects of therapeutic Kineso taping on grade 1 & 2 knee osteoarthritis.

Based on the inclusion and exclusion criteria, i was able to get the sample size of 35 in the given time.

Now i want to publish article in international journal, but someone told me that international journals prefer studies with large sample size.

Can i continue the same study NOW and increase the sample size only and reevaluate the results?

Is it allowed/permitted/legal to continue same study by only increasing sample size?

In the last 10-15 years there is a certain trend to the appliaction of this type of hip replacement. In any case, I do not know if the long-term results are satisfactory. In the past, some 30-40 years age the Wagner cup has been very popular but the long- term results have not been  satisfactory. What is the situation today based on your personal experience with resurfacing hip arthroplasty ?