AO VET History book sample by AO Foundation

of A OVET irst 4

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Hist ory The F

Jörg A Auer Ortrun Pohler Martina Schlünder Ferenc Kása Gerhilde Kása Marvin Olmstead Björn von Salis Gustave E Fackelman

Since mythological, prehistoric times animals have been a significant part of human culture and civilization. Historically, it was an essential step forward in the development of mankind, when human beings learned how to tame, breed and domesticate animals. A wooden Egyptian cat sculpture (Fig 1) and a depiction of a horse transporting the sun (Fig 2) demonstrate the artistic creation of animal sculptures in ancient times. Throughout history animals have played different roles and have had different functions: they were adored, used for work, food and clothing, and utilized for their specific skills, which were often considered superior to those of human being. However, they have also been misused and neglected. The history of AOVET tells of the unique development of systematic orthopedic operative fracture treatment in the veterinary medical discipline on the basis of—and in analogy to—the methodology developed by AO/ASIF to treat systematic osteosynthesis in human patients. It shows that large and small animal veterinary surgeons and ultimately their patients profited from the clinical experience gained in the treatment of human patients.

Fig 1 Ancient Egyptian cat, 2700 years old (wood) (Museum Rietberg, Zurich, Switzerland).

Fig 2 Trundholm Sun Chariot, Denmark, 3400 years old. The horse and the wheels create the association of the rapid motion of the sun.

Table of contents Timeline of AOVET

1 Setting the field 2

How AOVET started

3 The Waldenburg Circle

4 Osteosynthesis in small animals 5

Maxlie the horse

6 Institutionalizing the Waldenburg Circle: the foundation of AOVET and pioneering work

7 The hop over “the big pond”

8 Spreading the word—AOVET Center Waldenburg 9

Consolidating the achievements of the AOVET founders

10 Special events 11 Epilogue List of AOVET Presidents References

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1 Setting the Field

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1 Setting the Field

Traditionally, in recent centuries in rural settings veterinarians were mainly occupied with the treatment of horses and cattle, which were mostly working and/or food-producing animals. If necessary they also took care of “small animals”, such as cats and dogs, as well as other domesticated animals. Expensive treatments were not afforded to cats and dogs as replacement was so natural and inexpensive. In the midnineteenth century the disappearance of horses as working animals and the advent of industrialization with increasing introduction of machines, such as tractors, had a strong impact on veterinarians not only regarding their professional identity but also economically [1–9]. Since then, horses have been primarily used for pleasure riding or various sports activities, such as racing, dressage, and show jumping, while cattle have been kept as food and fiber-producing animals. At the same time, particularly in the growing cities, small animals increased in large numbers. These animals were kept by their owners as pets, the most popular being cats and dogs [10, 11]. The emotional attachment to these animals resulted in the increasing commercialization of a pet’s life. Pets might have been economically unimportant for their owners but they had an economic value for breeders, the pet food industry, and for veterinarians. While at the beginning of the twentieth century small animal practitioners could be found only in small numbers and only in large cities, their numbers started to increase during the 1950s and 1960s and now dominate veterinary medicine and surgery [1, 2, 12]. Because pet owners have been ready to spend an increasing amount of time and money for their beloved, emotionally highly valued animal companions, veterinarians have been able to apply more demanding treatments.

The drastic modification of their patient population from large animals to small animal pets confronted veterinarians with new treatment regiments. Traditionally veterinarians had been trained on the basis of the functional pragmatism that ruled the lives of working animals [13–16]. In the context of pet ownership, however, the veterinarian’s mission changed. It was no longer about curing inexpensively or otherwise killing the sick animal. The treatment of pets closely followed the model of human medicine instead, something that was increasingly expected by pet owners. Veterinarians thus switched from a functional pragmatism to an “economy of love” as a basis for their work. This change, however, confronted veterinarians with the fact that they often did not know how to treat an animal according to human medical practice.

1 Setting the Field

Insufficiency in operative fracture treatment These problems were of particular relevance for veterinary surgery, especially in the field of trauma and orthopedic surgery. Modernization and industrialization had led to a rapid increase in the numbers of motor vehicles and, consequently, to growing numbers of animals injured in traffic accidents [19]. The injuries they suffered were more complicated than those caused by a simple accident, fall, or kick by another animal. Thus, the veterinarians were challenged quantitatively with more fractured bones and qualitatively with more complicated fractures. Whereas previously the injured animals would have been euthanatized, now their owners expected effort to be made to heal and save the lives of their pets. In the 1950s and 1960s, however, veterinarians’ knowledge and treatment options for dogs, cats, and horses with broken bones were limited, although certain adoptions from human trauma surgery had been made [17–24]. For operative fracture treatment in small animals, the most popular approach in Germany and Switzerland (as well as in other countries) was intramedullary nailing corresponding to the Küntscher technique (Fig 3a–d) [25, 26] and modifications thereof, like the Rush-pin application and the stacked pin nailing. The use of these elegant but somewhat tricky surgical methods was relatively widespread during that era, even though they had their limitations. In dogs intramedullary nailing was more demanding than in humans, since the cortex of the dog bone is thinner and more brittle, the diameter of the medullary space more diverse than in humans. Instability and subsequent complications, such as nonunions, pseudarthroses, and implant failures, were frequently the result. Also, the anatomy of long bones varies considerably among different breeds, making this technique difficult to standardize [27]. One of the German small animal surgeons of the 1950s, Dr Heinrich Müller, who studied intramedullary nailing techniques, blamed a blatant lack of accompanying scientific research and the ensuing lack of knowledge flow between the fields of human and animal fracture treatment for the poor results [28, 29]. Joint and near-joint fractures are difficult to stabilize with nailing techniques or with pins and cerclage techniques, except for some special methods that have been developed over time. Conservative fracture care with plaster of Paris casts and bandages as practiced in human medicine is rarely suitable for small animals, since the

patients usually destroy such applications. Thus, fracture treatment in small animals during the 1950s and 1960s was problematic and had many shortcomings.

Fig 3a–d a Mrs Willenegger’s dog named Kai. b Suffered a mid-shaft femoral fracture. c In the 1940s, Drs Knoll and Willenegger assisted Dr. Jacques Jenny insert a Küntscher nail into the medullary cavity, which led to complete healing of the fracture. d 14-week follow-up x-ray after complete fracture healing with the nail still in place (left) and x-rays 2 weeks later after nail removal (right).

1 Setting the Field

In large animals operative fracture treatment was extremely difficult, although occasionally attempts were undertaken. Dieter Prieur refers to an early case [27] from 1891, in Cairo, Egypt, where a city police horse that had suffered a broken jaw was successfully treated with a drilled wire suture (cerclage). After 10 months the horse was back to work. A publication in 1966 [30] reports on the osteosyntheses of fractures of the lower jaw in cattle by means of compression-plate applications, carried out in collaboration by a veterinary surgeon together with an experienced human surgeon. A brief look at human trauma surgery in the mid-1950s indicates that at this time many unsolved problems existed in the operative treatment of fractures. Many trauma surgeons characterized their field as the “Cinderella of modern surgery” [31, 32]. Trauma surgery and fracture care had not participated in the triumph of modern surgery in the late nineteenth and early twentieth centuries. One reason why fracture treatment was relatively unattractive to most surgeons was its conservative character. Most patients with fractured bones were treated with immobilizing techniques, such as plaster casts and traction. Operative fracture care was extremely demanding in terms of operative techniques, implant design and quality and asepsis. The associated risk of bone infection made it unsuitable for large-scale use. Complications occurred frequently but their reasons were rarely analyzed or understood. Only a few surgeons tried to make operative fracture care a viable option. Even in human fracture surgery not much systematic scientific research was conducted. Knowledge was usually based on personal experience of individual surgeons and not on larger systematic clinical or laboratory research. Aside from Gerhard Küntscher, who improved and expanded the intramedullary nailing technique, there were the esteemed surgeons Albin Lambotte and Robert Danis who applied their novel ideas to stabilize fractures with external transfixation devices and with screws and plates [33].

Systematic approach to osteosynthesis in human surgery developed by the AO group The breakthrough and spread of a systematic operative fracture treatment occurred with the founding of the Arbeits gemeinschaft für Osteosynthesefragen (AO) that took place on November 6, 1958, in Biel, Switzerland [1]. Based on private individual interest and driven by the search for improved and dependable osteosynthesis techniques, the five surgeons of the core group who initiated the formation of the AO (Maurice Müller, Martin Allgöwer, Hans Willenegger, Robert Schneider, and Walter Bandi) (Fig 4a–e) had met numerous times between 1952 and 1956 to exchange their experiences, concerns, and new concepts [33]. They concentrated increasingly on collaboration, systematic work, and the analysis of clinical problems. By 1957 they formulated essential preconditions for successful operative fracture treatment stressing the importance of a functional view of osteosynthesis. In December 1957 they decided on the formation of an “Association pour Osteosynthèse” [33, 34]. At an internal meeting in March 1958 they demonstrated and evaluated all osteosynthesis equipment available at that time. The results were disappointing and the five surgeons decided to develop their own instrument and implant systems and surgical methods for the different fracture types and orthopedic interventions. Professor Maurice Müller, the most highly motivated and most active of the group, presented an overview of the “aims and general principles of modern osteosynthesis in adults” that sounded almost like an AO program [44]. Among other aspects the following characteristic points were included: Aims: • Early postoperative mobilization and activation of near-fracture joints and muscles; this is very effective but must not be forced too much • Reconstruction of the anatomical conditions; this is a precondition for functional results

Basic Principles: • Continuity of asepsis from accident to healing; postoperative wound drainage; careful anatomical operation, reconstruction and reduction • The fractured area should be transformed into a stable block by the osteosynthesis • Where possible fragments should be set under compression for increased stability • Pseudarthroses tend to heal quickly under compression, but the source for the pseudarthroses should be detected and treated if required. The implant materials must be biocompatible

1 Setting the Field

The various aims and concepts were followed up meticulously, with astonishing momentum and personal engagement. To implement the agreed development of instruments and implants, Professor Müller visited Robert Mathys in spring of 1958 in his production company in Bettlach where he was working with stainless steel. Mathys started immediately to design and manufacture prototypes, so that the first samples of the 4.5 mm screws with the corresponding (round-hole) plates and implantation instruments were available already at the founding meeting in November of the same year. Thus, Mathys was the first manufacturer of AO implants and became the first exclusive producer of AO products (later to become Synthes products) and contributed substantially to the development of the equipment. The AO surgeons were highly successful because they approached operative fracture treatment on an unusually broad and systematic basis and, at a point in time, when important new techniques in various fields like metallurgy, physics, aseptic surgical techniques, and perioperative antibiotic management were developed and became available to solve major problems of bone surgery. They developed implants, instruments, surgical techniques, and after-care protocols simultaneously. They studied the biomechanics of the normal skeleton and of the injured and treated bones, and they investigated osteogenesis, and bone healing mechanisms under various conditions histologically and metabolically. In 1959 the AO Research Institute for Experimental Surgery was established in Davos through the particular initiative of

Fig 4a–e The principal founders of AO: (a) Martin Allgöwer, (b) Walter Bandi, (c) Maurice Müller, (d) Hans Willenegger, and (e) Robert Schneider.

Professor Martin Allgöwer and supported by the financial donations of the AO members. The Documentation Center for the clinical cases of the AO members was moved there, and a tissue culture laboratory was soon installed. This laboratory also addressed the question of metal toxicity and led to the early studies of biocompatibility of implant materials and their components by Dr Lotte Hulliger and Ortrun Pohler [35, 36]. Professor Herbert Fleisch led the AO Research Institute during the early years. His special research interests were bone biochemistry and metabolism, as well as bone pathology and the development of medications for bone disorders. From 1967 onwards Professor Stephan Perren led the Research Institute as its director and constantly expanded its facilities in addition to its organization, engagements, and the subjects of research at the highest level. He implemented biomechanical, biological, and mechanical testing and analyses, histological and clinical research, cell and organ culturing, and biocompatibility studies, as well as the development of implants and instruments. The AO Research Institute also provided enormous teaching and operative support for the annual Davos courses. The accumulated knowledge and expertise of the AO Research Institute contributed tremendously to the success of the AO concepts and the AO Foundation. After the Straumann Institute in Waldenburg was contacted by the AO in 1960 (see next chapter), it became instrumental in developing implant materials that possessed the required biocompatibility, corrosion resistance, and variability in mechanical properties [32, 33]. Along with other developments, the Straumann Institute became the second exclusive producer in 1962 [34–36]. The collaboration of the surgeons with the producers, engineers, physicists, metallurgists, biologists, and scientists contributed to development and progress and provided specific research techniques. Also, the availability of antibiotics at that time and improved antiseptic management reduced the risk of infection and supported the surgical success. The AO, together with its producers, pursued a strategy of standardization and quality control of instruments and implants as well as teaching correct equipment handling and corresponding operative techniques. For this purpose, the AO established the Technical Commission (TK) in 1961 for the guidance, testing, and acceptance of new developments in AO surgical equipment and methods.

1 Setting the Field

In so doing, they had organized a system of quality control and assurance, many years before today’s required international quality-management standards (ISO). However, with the propagation of the “compression-osteosynthesis technique” where screws and plates created reduction of the fracture gaps and axial compression at the end of the bone fragments, the AO surgeons met with opposition from their colleagues because the common opinion then was that compression destroyed the bone. Another related controversy arose surrounding the phenomenon of “callus-free healing”, which was detected in connection with the stable osteosynthesis techniques. At that time it was generally accepted that callus formation should be interpreted as a sign of progressive bone healing. Thus, surgeons concluded wrongly that the missing callus with stable internal fixations indicated a lack of bone healing. The experimental clinical and histological research conducted by Professor Hans Willenegger (Hospital Liestal near Basel) and Professor Robert Schenk (University of Basel at that time) demonstrated that with sufficiently stabilized osteotomies primary direct bone healing occurs without callus formation [37, 38]. Stephan Perren showed with his strain gauge measurements on experimental compression osteosynthesis on sheep in combination with related histological investigations that no bone resorption occurred with the exerted compression [39]. These scientific findings, combined with the many documented successful clinical cases, soon convinced the surgical orthopedic community. Meticulous documentation and critical evaluation of the clinical cases, as well as learning from complications, were important milestones of the AO philosophy. The yearly spring and fall closed membership meetings and open scientific sessions provided a forum for information, exchange of experience, and coordinated clinical projects. The AO members obtained more and more requests from their colleagues who wanted the AO equipment for their own surgery. Since the operation techniques were subtle and the risks of probable complications high, the AO decided to sell the equipment only to surgeons who were well trained and attended a special instruction course. At the same time it was agreed with Dr Peter von Rechenberg of Synthes AG, Chur, that earnings from the sale of the surgical equipment would flow back into the research. In December 1960

the first AO course was offered in Davos with lectures and practical exercises using original implants and instruments on anatomical specimens. The Davos courses were then offered on an annual basis and have grown in numbers and diversity of their content. Additional courses expanded internationally. Corresponding teaching material was developed and continually updated including videotapes for practical exercises. The first AO manual with descriptions of the various operation techniques for typical fracture treatments and general introductory information was published in 1963 [40]. This was followed by a series of updated editions of AO manuals [41–44] in different languages (the third edition contains sections on biomechanics, classifications of fractures, soft-tissue injuries, and other interesting topics [43]). The teaching, documentation, classification, interdisciplinary research, specific surgical equipment and methodology, and an international radius of action were the important cornerstones of the AO’s development. However, the essential element was an unusual willingness to cooperate and exchange information and experience, sustained by a sincere and wholehearted human attitude characterized by responsibility, honesty, and tolerance of each other. This specific characteristic of AO membership supported the formation of an AOVET organization, about a decade after its own founding. AO was generous in sharing its surgical methodology and scientific knowledge with the fledgling discipline of veterinary orthopedic surgery. In this way, a group of veterinary surgeons enabled to develop efficient and dependable osteosynthesis methods on a systematic basis for small and large animal fracture treatment. Some of the AO principles and equipment could be transferred directly to veterinary surgery, some of them needed adjustment and modification, and new solutions had to be developed as well. In addition, the veterinarians had to learn many of the general surgical preconditions and skills, which are standard procedures in the treatment of human patients. Moreover, the veterinarians had to undergo numerous experiences similar to those of the AO founders.

2 How AOVET started

How

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2 How AOVET started

Several fortunate coincidences led to the formation of the initial group of veterinarians, human trauma surgeons, and scientists that eventually resulted in the founding of AOVET. A horse shot dead When Dr Björn von Salis (Fig 5) was a teenager he was taken to the local horse races. In the middle of a race one of the horses fell with a broken leg and shot dead on the spot. This was a crucial experience for the young visitor and it led him to become a veterinarian. Von Salis told himself that such things could not be tolerated, and dedicated the rest of his life to finding solutions to this problem. When he worked as a senior veterinarian at the Equine Hospital of the University of Bern in the 1950s, he noticed how underdeveloped the facilities for equine surgery were. Neither adequate instruments nor surgical techniques were available for equine trauma surgery. Also, horses could not be anesthetized for longer than 30 minutes. At that time horses were exclusively anesthetized with intravenous chloral hydrate. Therefore, von Salis decided to first examine the problem of anesthesia. Veterinary anesthesia was more advanced in the UK, where Leslie Hall was starting to use halothane for inhalation anesthesia. Intrigued by this work, von Salis decided to go there and study these new techniques. After returning to Switzerland he introduced these techniques into the standard procedures at the Equine Hospital of the University of Bern and later published an article on equine anesthesia [45]. His second goal for improving equine surgery was the development of new transportation facilities for horses after an accident. Since horses were typically put to death humanely, little experience existed on how to transport an injured animal and what kinds of devices were needed to load an injured horse into a trailer, either in a standing or recumbent position. This challenged him to construct an ambulance vehicle equipped with an x-ray unit and first-aid facilities.

In the mid-1960s von Salis left the University of Bern and moved on to work in a small animal practice in Basel so that he could complete his specialization degree in small animal surgery and medicine. There he became friends with Ferenc (Feri) and Gerhilde (Geri) Kása, small animal veterinarians who practiced and lived in Lörrach near Basel on the German side of the Rhine river. Von Salis never forgot the need to look for adequate implants and instruments for trauma surgery in horses.

Fig 5 Björn and Cathrin von Salis during an AO function in Davos.

2 How AOVET started

Dr Guggenbühl’s huge dogs Before Dr August Urs Guggenbühl became the chief and general surgeon at the Hospital in Grenchen (near Solothurn) in 1957, he worked as chief resident at the Liestal Hospital under Hans Willenegger, one of the AO Founding Fathers, Guggenbühl was the youngest of the 13 AO founding members in 1958. Urs Guggenbühl was the proud owner of seven dogs (Irish Wolfhounds, a Great Dane, a Bordeaux Dane, a Mastiff, as well as a Greyhound) who used to accompany him almost everywhere in his Jaguar convertible (Fig 6). He was renowned for showing up with all of them in tow. Actually, he had never planned to have so many (and such huge) dogs. He had ended up with them by accident but he loved to live with them. Of course, Guggenbühl was in contact with the local veterinarian at that time but he was not impressed by the techniques and equipment used for fracture care in animals. Therefore, he started teaching the veterinarian the AO Principles of osteosynthesis. Occasionally, Guggenbühl himself carried out a surgical intervention with the veterinarian’s assistance.

Fig 6 Urs Guggenbühl in front of his house with four of his prize-winning giant dogs.

Afterward he discussed these animal cases with his AO colleagues. Willenegger, who knew about the veterinary activities in Waldenburg, introduced Guggenbühl to the veterinarians, which led to his engagement as a veterinarian teacher. An animal owner and engineer In 1954, Dr Fritz Straumann (Fig 7) and his father Professor Reinhard Straumann established a private research institute in Waldenburg (near Basel) to facilitate further development, investigation, and testing of watch-spring materials and watch-spring designs that the elder Straumann had invented. The spring metal alloys were sophisticated and their production processes required close attention and metallurgical expertise. Since Fritz Straumann was very interested in all natural sciences and technology, he expanded their research beyond the watch industry into other areas as well. The concept was to invest the earnings from their patents into their research institute. In 1960 Fritz Straumann was contacted by Willenegger, who was seeking assistanceto improve the material quality of AO implants because there were problems with the corrosion and failure of plates and screws. Ortrun Pohler (Fig 8) analyzed the defect implants and found that impurities and an insufficient composition of the stainless steel were the reason for the corrosion. The breaking of the implants was caused by material fatigue where a crack propagates with time through the material under alternating bending stresses (cyclic loading). Such critical local bending stresses can be generated under the load bearing of the patient, in cases where bony defects and instability of the osteosynthesis are present. With time this phenomenon was studied in depth [46]. Straumann developed of a stainless steel with high corrosion resistance and variable mechanical properties that were particularly suited for clinical applications. This material became the model for the internationally standardized implant steel that is currently used. Straumann volunteered to help to the AO surgeons, and was able to assist in the development of various techniques to resolve clinical biomedical problems.

Fig 7 Fritz Straumann giving an address during an AO function.

Fig 8 Ortrun Pohler a scientific member of AO and an AOVET member working on a publication.

2 How AOVET started

For example, he developed the first bone saw that was able to cut thin undecalcified embedded bone sections for histological microscopy. This provided bone histology with a technique to obtain a more detailed and realistic visualization of the microscopic bone structure and further understanding of bone remodeling and healing. Fritz Straumann was also a passionate horseman. He owned a number of horses and kept them at stables and an indoorriding arena close to a nearby castle called Bechburg (Fig 9), a place also used for occasional veterinary activities. Straumann also owned dogs (blood hounds and bassets). In 1967, when one of the dogs became sick, Fritz Straumann took it to Dr Christoph Uehlinger, a small animal practitioner in Basel, and there he met Björn von Salis.

Fig 9 Bechburg, near Waldenburg, the place where AOVET was founded.

2 How AOVET started

Getting together Christoph Uehlinger told von Salis about Straumann’s involvement in the development of instruments and implants for fracture care in humans, and von Salis immediately recognized that Straumann could be instrumental in solving his third problem concerning trauma surgery in horses: the design of appropriate instruments and implants. Von Salis helped treat Straumann’s dog and started visiting the dog and its owner at their home in Waldenburg. He had prepared himself very well for his first visit. He took his publications on horse anesthesia and a Dutch book by Verhaar on operative fracture management in large animals with him to Waldenburg [47]. In those days fracture treatment in horses was in its infancy. The two men got along very well from the start. Indeed, their first conversation lasted until 3:00 am in the morning. When von Salis asked Straumann at the end of their meeting if he could help him with the instrumentation problem, the engineer promised every kind of help and support, including the offer to use his laboratories. As a first step Straumann set his metallurgist, Dr Ortrun Pohler, to work on the “animal-project”. She was already experienced in the research and development of AO implants and was in close collaboration with the AO Research Institute in Davos. They agreed to meet every Wednesday afternoon at the Institute in Waldenburg to explore the conditions under which the AO techniques and equipment could be applied to fracture management in animals. Björn von Salis attempted to involve Christoph Uehlinger in the devlopment of implants for the veterinarians. When he declined, von Salis asked Feri and Geri Kása (Fig 10a–b) who jumped at the chance because they previously had a frustrating experience treating a radioulnar fracture without proper instrumentation and implants. A week later they joined Björn von Salis on his visit to Waldenburg as they were searching for more efficient internal fixation methods to overcome the limitations of the common nailing, pin, and cerclage techniques they were using so far. Although they had developed particular skills in nailing fractures in small birds (Fig 11a–c) [48], this was the start of intense work on veterinary osteosynthesis in large and small animals.

b Fig 10a–b Ferenc (a) and Gerhilde (b) Kása, the first small animal surgeons working with AO techniques.

Fig 11a–c a Preoperative x-rays of a fracture of the distal metaphysis of the tibiatarsus in a canary bird; treated by Feri and Geri Kása. b Intraoperative picture showing the incision. c Postoperative x-rays following intramedullary pinning of the fracture with a straight needle.