Fractures of the femur.

The most common indications for the use of ESF in femoral fractures are closed transverse, short oblique, and minimally comminuted fractures in the central one third of the bone. External skeletal fixation is usually used in combination with IM pins and wiring techniques. During the process of open reduction and internal fixation, the surgeon should strive for accurate anatomic alignment and stability at the fracture site. The fixator is applied after the internal fixation is in place and the surgical wound is closed. The number of fixation pins placed in each fracture fragment depends on the type of fracture and the stability gained by internal fixation. Partially threaded fixation pins are recommended. They are inserted through skin stab incisions with low-speed power equipment. Recent modifications of the Type Ia fixator may increase fixator rigidity. Important postoperative concerns include exercise restriction, pin tract care, and protection of the fixator from the environment. Complications associated with ESF can be minimized by realizing its indications and limitations.     

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.     

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.     

Pinless External Fixation of Mandible Fractures in Cattle

Objective — This report describes our experience with a new technique for stabilization of mandibular fractures in cattle using a pinless external fixator.
Study Design — Mandibular fractures were stabilized with a pinless external fixator, which is a modification of a unilateral AO/ASIF (Association for the Study of Internal Fixation)-fixator in which pins are replaced with bone clamps.
Animals — Seven dairy cattle between 1 and 5 years of age.
Methods — Fracture stabilization was achieved by using the pinless external fixator. Postoperative management included intravenous administration of sodium chloride-glucose and antibiotics. A suspension of ruminal contents from a normal cow together with linseed and grass pellets was administered with a gastric tube.
Results — Three to 10 days after surgery six of seven cows masticated comfortably. The only failure was a yearling with a 10-day-old open infected fracture. This animal was slaughtered 9 days after surgery because of additional problems. In six cases there was enough callus formation 33 to 54 days after surgery to stabilize the fracture. The fixation devices were removed under heavy sedation. The major complication was bone sequestration at the fracture site, which required additional treatment.
Conclusion — The pinless fixator has proven satisfactory for external stabilization of unilateral horizontal ramus fractures of the mandible in cattle.
Clinical Relevance — The technique provides good stability without penetration of the medullary cavity and damage to the tooth roots. Other advantages of the technique include ease of application, minimal surgical trauma, and the short surgical time for application.     

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.     

External skeletal fixation for stabilisation of comminuted humeral fractures in cats

Thirteen feline humeral fractures were stabilised using external skeletal fixation alone or in combination with supplementary devices. Eleven of the 13 fractures healed. Pins placed in the distal humerus should be angled to avoid the supracondylar foramen and radial nerve. An intramedullary pin in combination with external skeletal fixation is indicated for mildly comminuted reconstructable fractures. For severely comminuted humeral fractures, closed application of an external skeletal fixator may be preferable to open reduction and internal fixation to provide healing and is recommended as an alternative to amputation.     

Application and postoperative management of external skeletal fixators.

Application of external skeletal fixation involves preoperative assessment of the fracture with regards to healing potential of the bone and stabilizing requirements of the fixator. The fixator can be used alone or with supplemental (IM pin, cerclage, hemicerclage, Kirschner wires, bone screws) fixation to counteract shear, bending, and torsional forces at the fracture site. In addition, cancellous bone grafting can be used to enhance fracture healing. Rigid frames should be based on predrilling pilot holes followed by slow speed or hand insertion of smooth and threaded pins. Precise knowledge of regional anatomy precludes iatrogenic neurovascular or muscular tissue damage, which, subsequently, improves patient morbidity. Postoperative care of the fixator consists of bulky wraps to control pin-skin motion and cleaning of pin tract drainage sites. "Dynamization" or bone loading can be performed during fracture healing to stimulate osteosynthesis. This involves staged disassembly and reduction of frames by removing pins and connecting rods.     

Use of an aiming device for application of a type-II (bilateral) external fixator to a fractured tibia of a dog

An aiming device was used to guide insertion of fixation pins in a type-II (bilateral) external fixator stabilizing an open canine tibial fracture. This device, designed by the Swiss AO group, has multiple applications in orthopedic surgery, because it accurately locates the exit point of a pin or drill hole on the far side of a bone or fractured bone fragment. When used with the type-II external fixator, it greatly facilitates pin placement by ensuring that, as a pin emerges from the bone, it is in line with the second clamp on the opposite connecting bar.     

Use of external skeletal fixators in the repair of femoral fractures in cats

This paper reports the results of fixation of 35 femoral fractures in cats using an external skeletal fixator alone or in combination with supplementary devices. All the fractures healed. The average time to fixator removal was eight weeks and two days. The external skeletal fixator offers a method of repairing many types of femoral fractures in cats allowing sound orthopaedic principles to be maintained and producing a successful outcome.     

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.     

Treatment of inherently unstable open or infected fractures by open wound management and external skeletal fixation

OBJECTIVES: To assess the use of external skeletal fixation with open wound management for the treatment of inherently unstable open or infected fractures in dogs. METHODS: A retrospective review of 10 cases. RESULTS: Fracture stabilisation and wound management required only a single anaesthetic, and despite the challenging nature of these injuries, the final outcome was acceptable or good in every case. However, minor complications associated with the fixator pins were quite common, and two dogs developed complications which required additional surgery. CLINICAL SIGNIFICANCE: Open management of wounds, even when bone was exposed, proved to be an effective technique, and external skeletal fixators were usually effective at maintaining stability throughout an inevitably extended fracture healing period.     

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.     

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.     

Influence of an interdental full pin on stability of an acrylic external fixator for rostral mandibular fractures in dogs

OBJECTIVE: To determine total stiffness and gap stiffness of an external fixation system in a canine mandibular fracture gap model incorporating a full interdental pin as the only point of rostral fixation in a bilateral type-I external fixator. SAMPLE POPULATION: 10 canine mandibles. PROCEDURE: Bilateral mandibular ostectomies were performed between premolars 3 and 4. A type-I external fixator incorporating a full interdental pin was placed to stabilize a 0.5-cm fracture gap. Four pin configurations (intact mandibular bodies with fixator; ostectomized mandibular bodies and complete fixator; ostectomized mandibular bodies with caudal pins of rostral fragment cut; ostectomized mandibular bodies with all pins of rostral fragment cut) were tested in dorsoventral bending 5 times on each mandible. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were determined for each configuration on a materials testing machine. RESULTS: Total stiffness of intact mandibles was significantly greater than that of ostectomized mandibles, regardless of external fixator configuration. However, total stiffness and gap stiffness were not significantly different among different external fixator configurations applied to ostectomized mandibles. CONCLUSION AND CLINICAL RELEVANCE: External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations that had 2 or 4 additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically, avoiding iatrogenic trauma to teeth and tooth roots.     

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.     

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.     

Clinical Use of Recombinant Human Bone Morphogenic Protein-2 in a Whooping Crane (Grus americana)

Objective— To report use of recombinant human bone morphogenetic protein-2 (rhBMP-2) as adjunctive therapy for treatment of a comminuted, open, proximal humeral fracture in an avian species.
Study Design— Clinical report.
Animals— A 3.5-month-old male whooping crane ( Grus americana ).
Methods— An open, severely comminuted humeral facture was stabilized with an intramuscular (IM) pin/type IA external skeletal fixator with tie-in configuration. rhBMP-2 was applied in a calcium phosphate matrix (CPM) paste directly to the fracture site as a bone graft substitute. Radiographic evidence of bone healing was monitored for 14 weeks.
Results— Substantial bony callus was evident at 4 weeks and at 8 weeks there was bridging callus with obvious bony remodeling. The fixation was destabilized at 9 weeks by IM pin removal, bone healing progressed and the fixator was removed at 11 weeks. By 14 weeks both cortices had been re-established with continued callus remodeling evident.
Conclusion— rhBMP-2, applied in a CPM paste, was used as a bone graft substitute in the treatment of a comminuted, open humeral fracture in a whooping crane.
Clinical Relevance— Use of rhBMP-2/CPM should be considered in treatment of avian fractures.     

Maxillofacial and mandibular fractures.

Any traumatic event that produces maxillofacial and/or mandibular fractures generally results in gross and usually severe patient disfigurement and often results in the patient's inability to eat and drink. These fractures are exceptionally rewarding cases as simple techniques may be performed resulting in a successful functional outcome (ability to eat and drink) within a very short period of time (24 hours) after fracture stabilization. A markedly improved cosmetic appearance follows shortly thereafter once inflammation and edema resolve. The primary principle of fracture treatment, ie, providing stable fixation to the bone fragments, may be successfully used with wiring techniques only through an appreciation and proper application of biomechanical principles. Knowledge that bending forces (divided into their tensile and compressive components) are the primary forces to be neutralized dictates the use of the wiring techniques outlined as the "standard" to which all other methods of fixation for maxillofacial and mandibular fractures are compared. The location of the tension-band surface of the bone, the alveolar (oral) surface, dictates the most appropriate position for wire placement. Successful treatment is predicted on obtaining a cosmetically acceptable and functional result (Fig 29). Anatomic reduction and rigid fixation of fractures that can be reconstructed piece-by-piece creates optimal conditions for uncomplicated healing. Fractures in which bone loss or severe comminution exists, and which cannot be anatomically reconstructed, must be reduced using dental occlusion as the template for fracture fixation, thereby avoiding malocclusion. Excessive leverage on the bone fragments may occur secondary to malocclusion, resulting in an increased risk of complications (fragment motion, loosening of implants, infection). Some fractures with comminution or bone loss may not be suitable for wire fixation and must be treated by alternate methods (eg, external skeletal fixators, plates).     

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.