Use of a hybrid external skeletal fixator for repair of a periarticular tibial fracture in a Patagonian cavy

An 8-week-old female Patagonian cavy was examined because of acute right hind limb lameness; radiography revealed a moderately displaced, comminuted fracture of the proximal third of the tibia. The fracture was stabilized with a hybrid external skeletal fixator. Two Kirschner wires were placed in the main proximal fragment, parallel to the tibial plateau and at right angles to each other. These wires were connected to a partial circular external fixator ring. Three half pins were placed in the distal fragment, and a straight connecting rod positioned on the medial side of the limb was connected to these pins and the fixator ring. A second connecting rod was positioned on the craniomedial side of the limb and was connected to the fixator ring and a fourth half pin in the distal fragment. The fracture healed without complications, and the fixator was removed 3 weeks after surgery. Hybrid external skeletal fixators combine the benefits of circular and linear external skeletal fixation methods, enabling rigid fixation of periarticular long bone fractures without adversely affecting mobility of the adjacent joint.     

Comparison of fixation methods for treatment of long bone fractures in llamas and alpacas

Objective: To determine outcome after repair of long bone fractures in llamas and alpacas. Study Design: Case series. Animals: Llamas (n=11) and alpacas (8). Methods: Medical records (1998–2008) of camelids with long bone fractures were reviewed for history, repair method, and complications. Outcome was also assessed by owner telephone questionnaire. Results: Mean age at repair was 39 months. There were 8 males and 11 females. Fracture distribution was tibia (n=6), metatarsus (5), metacarpus (4), radius and ulna (2), humerus (1), and femur (1), with 13 closed and 6 open fractures. Fracture repair was by internal fixation (n=11), external fixation with a transfixation pin cast (5), external coaptation (2), and cross‐pinning (1). In 1 llama, the limb was amputated to revise a failed external fixation repair. Seventeen animals (89%) were discharged, and 2 were euthanatized. Outcome was available for 13 animals: 9 were used for breeding and 4 as pets. Fewer major complications occurred with internal fixation than with external fixation with a transfixation pin cast (P<.005); however, there were no significant differences in minor complications between groups. Conclusions: Internal fixation with bone plates was associated with fewer major complications than external fixation with a transfixation pin cast.     

Unifocal internal and external bone lengthening with circular external skeletal fixator in 5 dogs

The purpose of this study was to investigate the effectiveness of treatment of long bone defects and extremity shortness in 5 dogs using circular external skeletal fixator. In one case a bone necrosis and osteomyelitis shortened radius by 7.0 cm; however in others extremity shortening between 3.0 and 6.0 cm affected radius-ulna or tibia. 2 or 3 rings of 80.0-100.0 mm diameters, and 3 rods were used as a circular external skeletal fixator. The distractions at the rate of 0.5 mm X 2 times/day were performed following a latent period of 3 days after the corticotomy. Unifocal internal lengthening for case 1 and unifocal external lengthening for the others were performed. Distraction was performed between 30 and 70 days (mean 50 days). It was noted that the circular external skeletal fixator was well-tolerated in all cases. The first usages of limbs in all cases were on postoperative day between 8 and 43 (mean 22 days). The radiographic follow-up examinations revealed a complete consolidation on postoperative day between 35 and 75 (mean 55.6 days). The fixators were removed on the postoperative day between 45 and 85 (mean 65 days). The treatment was successful in restoring the appropriate length of the limbs. After removing the fixator, functional and cosmetic results were graded as excellent in 3 cases, good in one case and fair in one case.     

A Novel Combined Method of Osteosynthesis in Treatment of Tibial Fractures: A Comparative Study on Sheep with Application of Rod‐Through‐Plate Fixator and Bone Plating

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod‐through‐plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep.     

Management of limb fractures in wapiti (Cervus elaphus): 22 cases (1993-1997).

OBJECTIVE: To determine treatment and outcome of a series of wapiti (elk) with fractures of the limbs. DESIGN: Retrospective study. ANIMALS: 22 wapiti. PROCEDURE: Medical records were reviewed to determine affected limb and bone, fracture configuration, method of treatment, outcome, and complications. RESULTS: 2 animals had fractures of the humerus; 8 had fractures of the radius, ulna, or both; 5 had fractures of the third metacarpal bone; 3 had fractures of the tibia; 2 had fractures of the femur; and 2 had fractures of the tarsal bones. Most fractures (n = 11) were closed, displaced, nonarticular fractures; 6 fractures were open. Four animals died or were euthanatized prior to fracture treatment, 2 were not treated because fractures had already healed, and 14 underwent fracture repair. In the remaining 2 animals, the affected limb was amputated. Five animals developed nonfatal complications (wound dehiscence, osteomyelitis [2 animals], delayed union, and malunion) and 2 developed fatal complications (gastrocnemius rupture and femoral fracture during recovery). Overall, 16 animals were discharged from the hospital, and all were doing well at follow-up, 2 months to 4 years after discharge. CLINICAL IMPLICATIONS: In wapiti, limb fractures can be successfully treated by means of internal or external fixation. The high rate of fracture healing, even among wapiti with open fractures, should encourage veterinarians to repair limb fractures in wapiti.     

Management of fractures near the carpal joint of two calves by transarticular fixation with a circular external fixator

A four-ring circular external skeletal fixation device was evaluated for transcarpal fixation of compound fractures in two calves. Case 1 was an eight-month-old female Holstein-Friesian x indigenous breed calf weighing 72 kg, which had a Salter-Harris type II fracture at the distal metaphysis of the right radius/ulna with an open contaminated wound on the medial aspect of the carpus. Case 2 was an 18-month-old crossbred Haryana heifer weighing 105 kg, which had a comminuted fracture at the proximal end of its left metacarpus with severe soft tissue trauma and an open wound on the medial aspect. In both cases, the fractures were repaired with four-ring circular fixators by fixing the proximal two rings in the distal radius/ulna and the distal two rings in the metacarpus. Postoperatively, both calves were treated with analgesic and anti-inflammatory drugs and antibiotic, and the pin-bone interfaces and the open wound were cleaned regularly with povidone-iodine solution. In both animals weight bearing was good to excellent in the immediate postoperative period. The fixator was well maintained and tolerated by the animals until the fractures healed after 45 to 60 days. The movement of the carpal joint was slightly affected when the fixator was removed on day 60, but a follow-up examination after one year showed that both calves had normal functional usage of the limbs.     

In vitro biomechanical properties of linear, circular, and hybrid external skeletal fixation devices for use in large ruminants

OBJECTIVE: To report the biomechanical properties of 3 external skeletal fixation (ESF) devices for use in large ruminants. STUDY DESIGN: In vitro biomechanical testing of ESF constructs. SAMPLE POPULATION: Adult buffalo (weighing, 250-350 kg) tibiae (n=27). METHODS: ESF constructs (bilateral linear fixator [BLF], 4-ring circular external fixator [CEF], and hybrid fixator [HF]) were made using mild (low carbon) steel implants plated with nickel and cadaveric buffalo tibiae. After ESF application, a 1 cm mid-diaphyseal gap was created. Constructs were loaded to failure, on a materials testing machine, in axial compression (n=5/ESF type) and craniocaudal bending (n=3/ESF type). In addition, 3 CEF constructs were tested in intact tibiae under craniocaudal bending. RESULT: In compression, HF was the strongest and most rigid construct; yield load was significantly higher for HF than for BLF or CEF. Under bending, both CEF and HF had similar strength and modulus of elasticity. Strength for BLF was higher than CEF and HF, whereas the reverse was true for modulus of elasticity. CONCLUSIONS: ESF made from mild steel for use in large ruminants could withstand相似文献   

Management of Tibial Fractures Using a Circular External Fixator in Two Calves

Objectives: To report the repair of tibial diaphyseal fractures in 2 calves using a circular external skeletal fixator (CEF). Study Design: Clinical report. Animals: Crossbred calves (n=2; age: 6 months; weight: 55 and 60 kg). Methods: Mid‐diaphyseal tibial fractures were repaired by the use of a 4‐ring CEF (made of aluminum rings with 2 mm K‐wires) alone in 1 calf and in combination with hemicerclage wiring in 1 calf. Results: Both calves had good weight bearing with moderate lameness postoperatively. Fracture healing occurred by day 60 in 1 calf and by day 30 in calf 2. The CEF was well maintained and tolerated by both calves through fracture healing. Joint mobility and limb usage improved gradually after CEF removal. Conclusions: CEF provided a stable fixation of tibial fractures and healing within 60 days and functional recovery within 90 days. Clinical Relevance: CEF can be safely and successfully used for the management of selected tibial fractures in calves.     

Instrumentation for external fixation.

External skeletal fixation is a very useful technique for managing many orthopedic problems in veterinary practice. The Kirschner apparatus has been the most widely used fixator for many years in veterinary orthopedics because of its versatility, simplicity, and economy in use. The medium-sized device has the widest indications and is easiest to begin with. The small size can be acquired later for use on cats and small dogs. The new "raised thread" fixation pin designs improve bone-pin integrity and can be used in combination with nonthreaded pins to decrease the incidence of postoperative complications and for economy. Acrylic-pin external fixators are particularly useful for treatment of mandibular fractures and transarticular application since they allow nonlinear placement of fixation pins in highly contoured bones. A commercial system, currently being developed, will have all the equipment and materials necessary for their application in a convenient kit. Circular fixators (Ilizarov design) use thin K wires placed under tension to replace rigid fixation pins. Their unique adjustability characteristics make them useful in the treatment of limb deformity and shortening. Many other human fixators can be used for veterinary application if the basic principles of fixators are followed. Instrumentation required for external fixator application include a pin driver, pin cutter, and wrenches. Although surgical versions of these materials are available, less expensive alternatives are available using gas sterilization instead of autoclaving. The use of selected orthopedic instrumentation such as a periosteal elevator, bone clamps, and curets will facilitate fracture management.     

Distribution of cortical bone in bovine limbs

Xenogenic bone grafts have been widely researched because they are not limited in terms of volume and size like autogenous and allogenic grafts, and the favored bone for xenografts is bovine bone. However, the efficacy of cortical bone from bovine limb for xenografts is not clearly known. In this study, the distribution of cortical bone in bovine humerus, radius, femur, and tibia were investigated. Each experimental bone was split longitudinally with a bone saw and bone marrow and cancellous bone were removed. The thicknesses of cortical layers in sample diaphyses were measured at 1cm intervals using a micrometer. The mean lengths of cortical portions were; humerus 14.7 +/- 2.3 cm, radius 19.0 +/- 2.6 cm, femur 19.0 +/- 3.2 cm, and tibia 23.0 +/- 3.1 cm. Thickest cortical bone was found at the distal caudal metaphysis of the humerus, the proximal caudal metaphysis of the radius, the craniolateral and caudomedial midshaft of the femur and the lateral and medial midshaft of tibia. The mean surface areas of cortical bone were humerus 187.4 +/- 15.44 cm2, radius 229.2 +/- 43.31 cm2, femur 295.8 +/- 8.93 cm2, and tibia 290.0 +/- 30.44 cm2. And, mean volumes of cortical bone were humerus 149.42 +/- 15.35 cm3, radius 166.26 +/- 20.02 cm3, in femur 220.45 +/- 22.73 cm3, and tibia 214.89 +/- 20.05 cm3. The results of this study can be used to produce cortical bone-based plates and screws.     

The external fixator in small animal orthopaedics

The external fixator is an increasingly popular means of fracture fixation in small animals. Pins inserted into the affected bone are clamped to a rigid metal rod adjacent to the limb, thus neutralising forces through the bone. This system of fixation is versatile and inexpensive, and is well suited to treatment of a variety of small animal and exotic injuries including open or comminuted fractures, fractures of the mandible and joint instability.     

Management of femoral fractures in dogs with unilateral semicircular external skeletal fixators

Objective: To report use of semicircular external skeletal fixators (ESF) for management of femoral fractures in dogs. Study Design: Prospective clinical study. Animals: Dogs (n=16) with femoral fractures (n=18). Methods: A semicircular ESF system composed of 6‐hole 45° or 5‐hole 40° carbon‐fiber arches, 6 mm threaded rods, half pin fixation bolts, 6 mm nuts, and negative profile end‐threaded half pins were used for open repair of femoral fractures. ESF configuration, complications, limb use, fixator removal time, and functional outcomes were evaluated. Outcome was graded as excellent, good, fair, or poor. Results: Seventeen fractures with sufficient follow‐up healed. Eight dogs started using the limb immediately after waking up from anesthesia whereas initial limb use was 1–4 days after repair in the other dogs. Time to fixator removal ranged from 28 to 63 days (mean, 38 days). Functional outcome was excellent in 13 cases, good in 4, and poor in 1 nonunion. Conclusion: Semicircular ESF combined with open surgical reduction can be used to successfully repair metaphyseal and diaphyseal femoral fractures in young growing dogs.     

Large segmental radius and ulna defect treated by bone transportation with the Ilizarov technique

An 8-year-old male Boxer with a severely contaminated open fracture of the left radius and ulna fracture, produced by a helicopter propeller, was treated using bone transport by the Ilizarov method. Extensive diaphyseal bone loss and soft-tissue vascular damage were present. The radius and ulna were stabilised with an Ilizarov ring external fixator. The bone defect was partially shortened and restored by gradual transport of a bone segment created from proximal segments of the radius and ulna. The external fixator was removed 4 fi months after the beginning of the latency period, due to instability caused by osteolysis around the wires. A cast was placed for 3 weeks. Although the bone transport had resulted in formation of approximately 4 cm of bone, the antebrachium showed approximately 50% shortening when compared to the contralateral limb. The infection was eradicated, and the dog was able to bear weight on the operated limb when walking.     

Fractures of the radius and ulna.

Fractures of the radius and ulna are common in the dog and cat. If treated inappropriately, complications may result. These include delayed union, nonunion, malunion, and growth deformities. ESF is a versatile method of fixation for fractures of the radius and ulna. Types that are applicable range from the simple type I to the complex type III fixator. In general, the more unstable the fracture, the more rigid the assembly must be to counteract fracture forces. There are three basic phases to consider when using ESF: (1) preoperative planning, (2) application of the ESF, and (3) long-term management. A deficiency in any one of these phases can lead to complications and an unsatisfactory clinical outcome. Although ESF can be used on many types of fractures, the technique is especially well suited for open or highly comminuted fractures when internal fixation is not applicable. In these cases, close attention must be paid to the integrity of the soft tissues. In addition, cancellous bone grafts should be placed either at the time of initial repair or in a delayed fashion after adequate vascularity has been established. Staged or complete removal of the ESF should be individualized to each fracture case. In general, staged disassembly or "dynamization" can begin when the bone and fixator begin to function as a composite as determined by radiographs. Complete fixator removal should be considered when the fracture exhibits clinical and radiographic evidences of union.     

Use of contoured bar transhock external fixators in 17 cats

Seventeen cats with injuries involving the distal tibia, talocrural joints, tarsus and metatarsus were treated with contoured connecting bar transhock external fixators as either primary or secondary fixation. The assemblies stabilised all the injuries successfully. Fracture union was achieved in 11 out of 12 cases. Excellent results were achieved in eight cats and the outcome was satisfactory in a further five. Those cats with injuries involving talocrural joint luxation with displacement and significant periarticular soft tissue disruption had poorer long-term results. Complications occurred in seven cases.     

Internal Skeletal Fixation Using a Kirschner Apparatus for Stabilization of Fracture/Luxations of the Lumbosacral Joint in Six Dogs: A Modification of the Transilial Pin Technique

A technique using a modification of the transilial pin technique for stabilization of fracture/ luxations of the lumbosacral joint was performed in six dogs. This technique used an internal skeletal fixator composed of two transilial pins secured with two double fixator clamps. Collapse (shortening) of the seventh lumbar vertebra (L7) was observed in five dogs without compromise of the vertebral canal. Kirschner wires placed across the articular facets as supplemental fixation devices migrated to the subcutaneous tissues in two dogs and were easily removed. Migration of the internal fixators was not observed during healing; vertebral canal dimensions were maintained in all cases, and the internal fixators were not removed after resolution of fracture healing. All fractures were healed within 6 to 12 weeks of surgery without evidence of pain, neurologic impairment, or long-term complications.     

Treatment of long bone fractures in South American camelids: 5 cases

An adult llama and four alpacas were referred with long bone fractures. The llama presented with a closed, comminuted fracture of the right metatarsal bones. Two of the alpacas presented with comminuted fractures of the proximal radius. One fracture was closed and one was open. One alpaca had a closed, comminuted fracture of the distal radius, and the final alpaca had a closed, oblique fracture of the metatarsus. A diagnosis was made in each animal on the basis of clinical examination and radiographs. All fractures were managed by open reduction and internal fixation using selective placement of lag screws and dynamic compression plates. Four animals made uneventful recoveries and no long-term complications were encountered. One alpaca was re-admitted for plate failure and non-union of the fracture 5 weeks after surgery. The plate and screws were removed and a transfixation cast was applied. The fracture healed, however the alpaca showed signs of radial nerve paralysis after the cast was removed. With confinement in a small yard, full function gradually returned to the leg over the ensuing 4 months. Using techniques recommended in other species, South American camelids are suitable candidates for long bone fracture repair using open reduction and internal fixation.     

Stifle joint luxation in the cat: treatment using transarticular external skeletal fixation

Extra-articular suturing techniques and transarticular external skeletal fixators were used to repair traumatic luxation of the stifle joint in four cats. Rupture of the cranial cruciate, caudal cruciate and medial collateral ligaments, together with injury to one or both menisci, were the most common injuries observed. The method of stifle repair was successful in all cases, but serious complications occurred when cats with transarticular external fixators were not kept confined indoors. Complications consisted of pin loosening and disruption of the fixator, or fractures through proximal or distal pins. Transarticular external skeletal fixation was considered to be a simple and effective method of maintaining short-term joint stability to allow healing of injured soft tissue structures. The apparatus facilitated early weightbearing and, on removal, allowed for the return of near-normal stifle function. Careful pin insertion and owner compliance in enforcing confinement are essential in minimising complications associated with immobilising the stifle joint using transarticular external skeletal fixation.     

History of external skeletal fixation.

The concept of external skeletal fixation was introduced by Malgaigne in 1840, with a spike driven into the human tibia that was held by a strap encircling the limb. The first readily available external fixator, the Parkhill clamp, appeared in 1897. By the 1920s, a number of adaptations of pins or screws inserted into bone fragments for external control of reduction and fixation had been published. Important developments in that era were triangular half-pin units and anchoring bone pins in both cortices. The Stader splint, which was the first half-pin splint to provide reduction as well as fixation, was used by surgeons in the U.S. Navy during World War II. The Kirschner-Ehmer splint, a veterinary modification of the Anderson splint for humans, was introduced in 1947. Popularity of external skeletal fixation declined in the 1950s because of poor results that may have been caused by errors of application. Improvements in fixator configurations and the skill and judgment of surgeons led to the current acceptance of the method.     

Incidence of and predisposing factors for nonunion of fractures involving the appendicular skeleton in cats: 18 cases (1998-2002)

OBJECTIVE: To identify the most common sites of and possible predisposing factors for nonunions in cats with fractures of the appendicular skeleton. DESIGN: Retrospective study. ANIMALS: 344 cats treated for fractures between 1998 and 2002, 18 of which developed nonunions. PROCEDURES: Information collected from the medical records included signalment; type of trauma; fracture location, orientation, and type; degrees of displacement and comminution; treatment; and outcome. RESULTS: The tibia and proximal portion of the ulna were identified as the most common sites for nonunions. Factors significantly associated with development of a nonunion included age, body weight, affected bone, fracture type, degree of comminution, and fixation type, with older cats, heavier cats, cats with fractures of the tibia or proximal portion of the ulna, cats with open fractures, cats with comminuted fractures, and cats with fractures stabilized with a type II external skeletal fixator being significantly more likely to develop a nonunion. Eleven of the 18 cats with nonunions had a successful outcome following treatment of the nonunion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in cats, fractures involving the tibia and proximal portion of the ulna are more likely to develop nonunions than are fractures involving other sites but that many factors may increase the risk of nonunion. Use of excessively large and rigid type II external skeletal fixators may be associated with development of nonunions; however, type II external skeletal fixators were commonly used to stabilize fractures in sites predisposed to nonunion.