Science, Technology and Medicine open access publisher.Publish, read and share novel research. Full Thickness Skin GraftsSaikat Ray1 and Krishna Rao2[1] Department of Plastic and Reconstructive Surgery, Northampton General Hospital NHS Trust, United Kingdom[2] Department of Plastic and Reconstructive Surgery, Sheffield Teaching Hospitals NHS Trust, United Kingdom1. The Evolution of Modern Total Knee ProsthesesEun-Kyoo Song1, Jong-Keun Seon1, Jae-Young Moon1 and Yim Ji-Hyoun1[1] Department of Orthopedic Surgery, Chonnam National University Hwasun Hospital, Hwasun, Korea1. MacIntosh DLHemiarthroplasty of the knee using a space occupying prosthesis for painful varus and valgus deformities. S Endres, A Wilke, Early experience with the NexGen® CR-Flex Mobile knee arthroplasty system: results of 2year follow-up.
While no one can say with absolute certainty what it would be like, the author does give readers quite a bit to consider if ever such journey was possible. If I ever get stuck in the Jurassic period I would want this book with me to help me survive.
IntroductionSkin is the largest organ of the human body and has a number of essential functions.
Posterior-substitution prosthesis showing that the post-and-cam mechanism offers no restraint to varus or valgus stability (Courtesy of Biomet)3.2.
Mobile bearing knee prosthesis, which reduces contact stress but preserves freedom of movement (Courtesy of Biomet)3.3. IntroductionMany types of prosthesis are used for total knee arthroplasty, and the evolution of knee arthroplasty, which has a history of almost 40 years, involves repetitious cycles of failure and development. S Ranawat, J Insall, J Shine, Duo-condylar knee arthroplasty: hospital for special surgery design.
S Laskin, The effect of a high-flex implant on postoperative flexion after primary total knee arthroplasty. The sections on how to butcher various different dinosaurs were amusing, but it could’ve been even more amusing if taken somewhat further, playing with even wilder speculations. During its early stage (1970-1974), instruments of the unicondylar, duocondylar, or hinged types were used, but these were eventually abandoned due to low success rates.
T Railton, Should the posterior cruciate ligament be retained or resected in condylar nonmeniscal knee arthro-plasty? Clinical results of the Oxford knee: surface arthroplasty of the tibiofemoral joint with a meniscal bearing prosthesis. J Pappas, Long-term survivorship analysis of cruciate-sparing versus cruciate-sacrificing knee prostheses using meniscal bearings. S Kim, Revision total knee arthroplasty with use of a constrained condylar knee prosthesis. P Sculco, History of the development of total knee prosthesis at the hospital for special surgery.
It acts as a water resistant barrier so that essential nutrients are not washed out of the body. A replacement for the total condylar type was successfully developed and became the model for total knee arthroplasty. H Burstein, The posterior stabilized condylar prosthesis: a modification of the total condylar design.
K Muratoglu, Highly cross-linked ultrahigh molecular weight polyethylene with improved fatigue resistance for total joint arthroplasty: recipient of the 2006 Hap Paul Award. J Wang, The early results of high-flex total knee arthroplasty: a minimum of 2 years of follow-up.
S Kim, Range of motion of standard and highflexion posterior stabilized total knee prostheses: a prospective, randomized study. Recently, unicondylar arthroplasty has produced good results in selected patients, and arthroplasty of the constrained or hinged type have been proven useful for revision surgery or combined surgery, respectively. S Thornhill, Press-fit condylar total knee arthroplasty: 5- to 9-year follow-up evaluation.
To solve the problem of the fixed bearing joint, a mobile bearing joint has been developed, and non-cemented fixed knee arthroplasty is receiving renewed attention. J Gregg, A randomised controlled trial of cemented versus cementless press-fit condylar total knee replacement: 15-year survival analysis. The skin plays an important role in sensation and contains a number of nerve endings that respond to heat and cold, vibration, pressure, touch and pain.
Much effort is being expended on the developments of new materials, such as, ceramics and cross-linked polyethylene, on new designs that maximize function and endurance, and on minimally invasive surgery.2. There are some illustrations but they are few and don't show all of the wildlife that is discussed.So what is this book then?
Interposition and resurfacing knee arthroplastyDuring the late 19th and early 20th century, interposition arthroplasty was attempted using soft tissues. It is imperative that skin cover is preserved in humans for all the reasons mentioned above.
In 1860, Verneuil proposed interposition arthroplasty, involving the insertion of soft tissue to reconstruct the joint surface.
Skin grafts are harvested from a donor site and transferred to a distant recipient site (bed) without carrying its own blood supply. Since then, pig bladder, nylon, femoral sheath, anterior bursa of the knee, cellophane, and many other materials have been used, but results have been disappointing.
It is not going to give you detailed information about all of the different species, as if that would be possible, but instead gives you practical on the ground information that you would need to successfully live where no humans have existed before. The graft relies on new blood vessels from the recipient site bed to be generated (angiogenesis).Full thickness skin grafts consist of the entire epidermis and dermis. These grafts are a simple and reliable method of achieving closure of skin defects where primary closure or healing by secondary intention is not possible. Having obtained successful results for mold arthroplasty in the hip joint, Campbell and Smith-Peterson proposed metal femoral mold arthroplasty[2], and McKeever and MacIntosh proposed hemiarthroplasty of the tibia, but all produced unsatisfactory results in terms of minimizing pain, and high rate of failures of the interposition [3], and thus, these procedures were not widely recognized.
The author uses modern day cities as a starting point on your journey to the Morrison Formation. Full-thickness skin grafts are generally used to resurface smaller defects because they are limited in size.
Ferguson [1] attempted resection arthroplasty for ankylosis or severe deformity caused by tuberculosis or infection. Have you ever wondered about what a trip from Tokyo to the US would involve 150 million years ago? They are invaluable for reconstruction of defects where good cosmetic outcome or a durable skin cover is necessary.
This procedure involved resecting cartilage from the knee joint and allowing knee joint movement along the subchondral surface. Common areas include defects on the face, scalp and hand, often following excision of skin lesions. When too little bone was removed, knees spontaneously fused, and when more bone was removed, knee had good motion but poor stability. Never considered mountain ranges, bodies of water or even the position of the continents themselves. The hinged prosthesisIn the 1950s, Walldius [4] developed a hinged prosthesis that replaced the joint surfaces of the femur and tibia, as subsequently, modifications of the basic hinged prosthesis design were made by many surgeons.
The hinged prosthesis allows the intramedullary stem to align with the artificial knee joint by itself, and is technically easy to perform since all ligaments and soft tissues can be removed due to the mechanical and structural stability of the prosthesis. Plasmatic imbibitionInitially, the skin grafts passively absorbs the nutrients in the wound bed by diffusion.
During the 1950s and 1960s, hinged total knee arthroplasty provided satisfactory results for a longer period of time in more patients than any other knee arthroplasty design used.
However, this method could not be widely used since this type of simple hinged prosthesis cannot replace the complex movements of the knee joint and because of a high failure rate due to early loosening caused by overloading the prosthesis and bone contact surface or by infection. The second section, after you have made the journey from your point of origin to the Morrison Formation deals with the landscape once you have arrived.

This enables the graft to survive the immediate post graft ischaemic period, which is for an undetermined period of time that varies according to the wound bed. This may be upto 24 hours for a graft placed on a bed that is already proliferative and 48 hours for a graft covering a fresh wound.A graft can tolerate an ischemic interval when placed on a poorly vascularized bed. The bicompartmental prosthesisIn 1971, Gunston [5] developed polycentric knee arthroplasty. First off there is an inland sea where we would expect Utah, Montana, Colorado, New Mexico and Arizona. Thick full thickness skin grafts appear to tolerate ischemia for up to 3 days while thin full thickness skin grafts survive for up to 5 days. This was done by adopting the concepts of low friction hip arthroplasty espoused by Charnley. The author goes over the basic geography of the area you may venture to into including rivers and floodplains. Gunston’s knee arthroplasty retained the collateral and cruciate ligaments to help absorb stress, and consisted of relatively flat tibial interposition of high-density polyethylene and a round femoral prosthesis, which replaced the posterior portion of femoral condyles. There is a great deal of information on finding minerals that you could use for day to day living including salt and iron.
These components were fixed to bones with bone cement, and replaced the complex movements of ‘femoral roll-back’. A great guide on the best places to look for these and several other basics for living in the area.
Inosculation and capillary ingrowthBy day 3, a fine vascular network is established in the fibrin layer between the graft and its recipient bed capillary buds from the recipient bed line up with graft vessels on the underside of the dermis to form open channels. Polycentric knee arthroplasty was initially successful due to improved mobility and movement range, but the fixation it provided was not sufficient.Geomedic knee arthroplasty was introduced by Coventry et al.
This is a time before grasses and flowers so finding out which plants can be used for food is going to be a primary objective. Proliferation of fibroblasts and deposition of collagen to replace the fibrin maintains skin graft adhesion to its bed.
This design was initially devised to sustain the cruciate ligament, but joint mobility was limited because of pathologic posterior cruciate ligament in some cases. Using modern descendants of ferns, conifers and other plants the author parallels their uses and preparation methods to avoid being poisoned or killed from your dinner salad. While you won't find lettuce, carrots or broccoli there is still quite a bounty of edible plants we have found in the fossil record and the book gives many suggestions on which ones might best suit our digestive systems.The last section discusses what most everyone was looking forward to, dinosaurs. RevascularizationBy day 5, new blood vessels grow into the graft and the graft becomes vascularized.
The anterior and posterior cruciate ligaments were usually removed, and the tibial prosthesis did not have an intramedullary stem to minimize the risk of infection and to maximize knee joint function for salvage procedures.
The connection between graft and host vessels develops further as the graft revascularizes.
However, the loosening of the tibial prosthesis became a major drawback.In the mid 1970s, duocondylar interposition was designed to resemble the anatomic structure of the knee joint [8].
Most of the descriptions are there to give you a basic overview of the most common dinosaurs you would see. Newly formed vascular connections continue to differentiate into afferent and efferent vessels. The femoral prosthesis connected with two unicondylar prostheses via an anterior bridge, and formed a joint, which was considerable wider than previous polycentric knee arthroplasties, with two flat tibial instruments.
Since this is based on the fossil record from the area we really don't know how complete this picture really is. There will undoubtedly be dozens or hundreds of creatures we never even knew existed but we can only really focus on the ones we do know.
The tricompartmental prosthesisIn the early 1970s, three types of condylar prostheses were developed, which opened the era of modern knee arthroplasty. After the first trip returns I'm sure they will make several modifications for the next groups to follow.So what does the book cover about dinosaurs? Harvesting a full thickness skin graftDifferent parts of the body vary greatly in terms of the appearance, colour, texture, thickness and vascularity of skin. All of these factors are taken into account when choosing a donor area appropriate to a certain defect.Full thickness skin grafts can be harvested from a number of areas in the body that have skin redundancy.
When the face is being grafted, the posterior surface of the ear extending onto the neighbouring post auricular hairless mastoid skin provides an excellent donor site in terms of skin colour and texture. However, the geometric and anatomic types were not produced continuously due to early loosening of fixation.
While dinosaurs are certainly the stars of the show the author includes lots of information on small reptiles, pterodons, fish and primative mammals.
The duocondylar type was further developed to produce the first total condylar prosthesis with a tibial stem by Walker et al. Not exhaustive but should be enough information to know what animals to avoid and which ones we may need to make living possible.The last few pages are the author imagining what a typical day living in the Jurassic might be like. The total condylar prosthesis is a design that removes anterior and posterior cruciate ligaments. The femoral prosthesis, which is made of chrome cobalt, has a symmetric femur with a double curve, which has a flat patellar trochlear groove. The tibial prosthesis is completely made of polyethylene, has good conformity in the flexion and extension states, has anterior and posterior lips in the tibial joint surface, and has eminence in the mid joint surface which provides anteroposterior and mediolateral stability. He does a great job of relating that it is more like going on an extended safari than the thrill a minute adventure you often see in movies.To be honest I can't think of any other book that I have read that is similar.
Still I was pleasantly surprised in that it was captivating in the subjects without being a text book.
The patellar prosthesis is of the half-ball type and is completely made of polyethylene, with a fixation lug in the middle, which is fixed with bone cement. It also challenges you to learn about all aspects of what this trip would entail without dumbing down the content. It tells you what you would probably find useful when trying to figure out if a plant is edible or if you need to avoid the large dinosaur you see across the clearing. Along with these total condylar prostheses, the duopatellar prosthesis was developed, which preserves the posterior cruciate ligament. This book is now surely one of my favorites and I know what I will revisit it in the future. This prosthesis is anatomically similar to the normal knee joint with respect to the femoral prosthesis trochlear groove, and forms a joint with a polyethylene patellar prosthesis. The early tibial prosthesis model could be separated into medial and lateral parts, but later a form communicating the bilateral parts was developed. The duopatellar prosthesis was developed into the kinematic condylar prosthesis, which was widely used in the 1980s[11]. Early total condylar prostheses did not allow roll-back in the flexed position and the tibial portion was located posteriorly, which reduced the mobility range when the flexion gap was not balanced. These Insall-Burnstein and kinematic interpositions became the foundation of modern knee arthroplasty. Despite the developments of modern joint replacement designs, complications of the femoro-patellar joint were frequent after knee arthroplasty in the 1980s and 1990s, which led to the development of today’s knee arthroplasty which increases contact surface in the femoro-patellar joint and prevents lateral displacement of patellar bone. Unicompartmental knee arthroplastyAlthough it has been used since its introduction in 1950s, the results of unicompartmental knee arthroplasty (Figure 1) remain controversial. In the early 1970s, several authors reported unsatisfactory results for unicompartmental knee arthroplasties but over the next decade, better surgical techniques and proper patient selection improved results [13]. Unicompartmental knee arthroplasty can be used in cases with up to moderate arthritis and when diseased is confined to one compartment.
Along with Repicci and Eberle’s [14] minimally invasive techniques, unicompartmental knee arthroplasty has aroused much interest.
As compared with total knee arthroplasty, the unicompartmental knee arthroplasty has the advantage of preserving anterior and posterior cruciate ligaments and of recovering almost the full range of motion of the normal knee joint.

It also boasts a small amount of bone loss and theoretically enables easier revision surgery [15].
The recently reported long-term endurance of unicompartmental knee arthroplasty is about 85-95%, which is similar to that of total arthroplasty. The first patellar resurfacing materials were metallic components, but this design was limited because of problems concerning metal to cartilage articulation. Subsequently, the polyethylene patellar prosthesis was developed and satisfactory results were obtained.
Present day knee arthroplasty became total knee replacement when patellar component was added.3.
Spectrum of prosthesis designsNowadays, many types of prostheses are used for total knee arthroplasty. However, controversy exists regarding which prostheses are the most appropriate for individual surgeons and specific patients. Posterior cruciate ligament retention versus substitution All knee arthroplasties require anterior cruciate ligament removal, but retention of the posterior cruciate ligament depends on the type of arthroplasty. The preservation type, in which posterior cruciate ligament is preserved, is considered better than the replacement type for performing functions, such as, climbing stairs, and has the advantage of simplifying revision surgery due to less loss of bone (Figure 2). However, knee joints with degenerative arthritis usually show soft tissue contracture, and when preserving the posterior cruciate ligament, the soft tissue balance is not easy to achieve, which possibly increases the risk of early failure due to polyethylene insert overloading caused by posterior cruciate ligament unbalanced tension [16]. Figure 3.Posterior-substitution prosthesis showing that the post-and-cam mechanism offers no restraint to varus or valgus stability (Courtesy of Biomet)When the posterior cruciate ligament substitution type is used, even degenerative knee joints with relatively severe deformities can achieve ligament balance, and when flexed at 60-70 degrees, the post of the tibial polyethylene contacts the cam of the femoral component and induces posterior placement of femoral bone, which allows relatively satisfactory roll-back and can achieve sufficient knee joint flexion (Figure 3) [17]. However, bone loss at the intercondylar notch makes revision surgery difficult, and fracture may occur intra-operatively or post-operatively in patients with small femurs. From the biomechanical perspective, neither posterior cruciate ligament preservation nor substitution types can totally replace the biomechanics of the normal knee joint. Mobile versus fixed bearing total knee arthroplastyTraditional fixed bearing knee arthroplasties have produced good clinical results at 10-15 years postoperatively. Unfortunately, problems associated with polyethylene wear can occur in the long-term, especially in young patients. This wear can be reduced by reducing contact stress at the joint surface and by improving the wear characteristics of the material used. Contact stress may be reduced by increasing conformity between the femoral component and the polyethylene insert. The development of mobile-bearing articulating polyethylene surfaces in implants for patients undergoing total knee arthroplasty reflects the efforts made by designers to optimize wear while addressing the complexities of function. However, the trade-off for conformity and free mobile range in fixed bearing knee arthroplasty makes marked improvements in contact stress near impossible. To solve this problem, mobile bearing interposition knee arthroplasty was invented to reduce contact stress but to preserve freedom of movement. In 1986, Goodfellow and O’Connor [18] invented Oxford knee arthroplasty, which is a mobile bearing knee arthroplasty of the bicondylar type (Figure 4), and subsequently, Beuchel and Pappas [19] invented the meniscus sustaining bearing, which boasts low contact stress. However, in the case of the mobile bearing insert, the bearing can be dislocated when flexion extension gaps are inadequate.
Non-cemented versus cemented knee prosthesesConcern over the long-term tolerance of bone cement fixation led to the development of a non-cemented fixation design in 1980. Most are coated or textured so that the new bone actually grows into the surface of the implant.
However, because they depend on new bone growth for stability, non-cemented implants require a longer healing time than cemented replacements.Non-cemented implants, unfortunately, showed higher failure rates than cemented knee arthroplasties due to aseptic loosening and bone loss. In all knee replacement implants, metal rubs against the polyethylene insert, and although the metal is polished and the polyethylene is treated to resist wear, the loads and stresses of daily movements generate microscopic particle debris, which in turn, can trigger inflammatory responses that result in osteolysis or loosening.Because non-cemented implants have not been used as long as cemented implants, comparisons after long-term use are not possible.
However, some studies have shown that non-cemented fixation has success rates comparable to those of cemented fixation [21]. Constrained condylar knee prosthesesRevision total knee arthroplasty is often associated with poorer outcomes due to bone loss and ligament damage, which can result in ligamentous laxity and imbalance. A constrained condylar knee design was developed to resist coronal moments in the plane caused by soft-tissue deficiency. Constrained condylar knee designs have the advantage of allowing changes in the center of rotation during flexion, and thereby, theoretically impart less tangential anterior-posterior stress across the prosthetic interface [22].
An early model of constrained condylar knee design was proposed by Insall et al, although similar to posterior cruciate ligament substitution knee arthroplasty, the polyethylene post is thicker and longer, which provides stability for valgus and varus movements as well as not posterior movements [23].
Excessive constraint is a problem when the LCCK is used and this causes failure by loosening the prosthesis. Thus, in difficult knee arthroplasty cases, usage may be determined during surgery by taking into consideration the need for constraint. Cross-linked polyethylene bearing The development of arthroplasty design and materials has led to long-term endurance, but the not infrequent need for revision due to polyethylene wear has been a cause of patient dissatisfaction.
To reduce polyethylene wear, a cross-linked polyethylene bearing was developed and used in hip replacements in 1990s, and thus, its effectiveness has been proven.
Its resistance to wear provides a promising solution for arthroplasty patients, especially today’s more active, physically demanding patients. High flexion type knee prosthesesGenerally, postoperative knee motion range for total knee arthroplasty is less than 120 degrees.
Recently, to obtain motion ranges similar to those of the normal knee joint, high flexion femoral prostheses with a thickened posterior portion of femoral prostheis and a wider contact surface with the bearing are being used to reduce contact pressure and wear (Figure 6). To prevent collision between the patellar ligament and bearing at high degrees of flexion, a high flexion bearing with an oblique cutting of the anterior bearing has been developed. Furthermore, many authors have reported that high flexion knee arthroplasty can result in smaller contact loadings and wider ranges of motion than previous knee arthroplasties. In addition to pain reduction and restoration of function, survivorship is also a decisive contributor to the success of TKA.
Thanks to its extended posterior condyle radius, which has been broadened all round, the NexGen CR-Flex system offer a larger contact surface during deep bending, and therefore, spreads contact stress over a large area. However, some authors [28, 29] have reported no increase of flexion when using high-flexion prostheses.
In particular, in a clinical study that used both knee implants, high flexion knee arthroplasty did not show a significant increase in knee joint flexion range. Ultracongruent polyethylene bearingsThe most important thing to remember when performing posterior cruciate ligament preserving knee arthroplasty is to balance the posterior cruciate ligament and prevent instability by ligament disruption when flexed.
For these reasons, deep-dished polyethylene insert (also called ultracongruent insert) was developed. This bearing insert has moderate conformity in coronal and sagittal planes, which can prevent edge loading caused from paradoxical anterior translation due to elevation of the anterior lip of the prosthesis, prevent elevation in flexion, and prevent posterior subluxation (Figure 7).
Ultracongruent bearings can reduce cam-and-post wear or fracture that may occur after posterior cruciate ligament substitution knee arthroplasties, and can prevent bone loss at the intercondylar cutting site. This bearing represents a new concept in that it can also maintain the posterior cruciate ligament and provide moderate conformity in total knee arthroplasty. ConclusionThe history of prostheses evolution follows a repetitive course of development and failure.
The continuous and rapid developments of biomechanics and of materials in the 20th century hugely expanded the information available.
Most knee replacements are now being performed with PCL-retaining or PCL-substituting prosthesis that have their merits and limitations, as discussed above.
New mobile-bearing devices, which address the issue of functional complexity, have been developed and have the potential to prolong implant durability. Nonetheless, prosthesis materials and the historical and current results of different types of prosthesis remain topics of discussion with respect to their indications and contraindications.

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