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.     

Coracoid fractures in wild birds: repair and outcomes

OBJECTIVE: To describe the surgical repair of the fractured avian coracoid and compare release rates back to the wild for birds treated surgically with those treated conservatively. DESIGN: Medical records of 17 birds presented to Healesville Sanctuary with fractured coracoids were examined retrospectively. Nine birds were treated conservatively and eight birds were treated surgically. Release rates back to the wild were compared between the two groups. RESULTS: Of the nine birds treated conservatively two were released back to the wild. Of the eight birds treated surgically six were released back to the wild. CONCLUSIONS: In this study greater success at returning birds with fractured coracoids to the wild was achieved with surgical repair than conservative treatment. Surgical repair is recommended for birds intended to be released back into the wild.     

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.     

Comminuted long bone fractures in cats caused by pneumatic gun shot and repaired using the external fixator "tie-in" technique

Five cats with femoral fractures caused by pneumatic gun shot wounds were treated using intramedullary pin/external skeletal fixation "tie-in" (IM/ESF tie-in) technique between 1997 and 2005. Clinical and radiographical examinations were used to assess bone healing, limb function recovery and complications. Clinical results as well as fracture healing were excellent in all five cats. The study showed that the IM/ESF tie-in technique can be used in cats for the treatment of comminuted femoral fractures caused by pneumatic bullets.     

Treatment of radius-ulna and tibia fractures with circular external skeletal fixator in 19 dogs

This study was carried out on 19 dogs of different breed, age and sex. 10 different types of radius-ulna and 9 tibia fractures were treated by circular external skeletal fixator. The cases were followed by clinical and radiological controls in the postoperative period. It was observed that the cases tolerated the apparatus well. There was no looseness of fixator stability and configuration during the 15-day interval examination. Complications like pin track, serous drainage and pin loosening were observed postoperatively. It was concluded that radiographic, clinical and anatomical data together with good preoperative planning, the Ilizarov Method and circular external skeletal fixator was successful for the treatment of open or closed fragmented radius-ulna and tibia fractures in dogs.     

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.     

Comminuted supracondylar humeral fractures repaired with a modified type I external skeletal fixator construct

Highly comminuted supracondylar humeral fractures were stabilised in six large-breed dogs with a modified type I external fixator using a craniomedial acrylic connecting column and an Intramedullary pin which was incorporated into the connecting frame. This construct provided sufficient stability to allow satisfactory bone healing in five of the six dogs, while premature removal of the intramedullary pin and external fixator resulted in subsequent refracture of the humerus in the remaining dog. Limb function at the time of final assessment was considered excellent in two dogs, good in three dogs and poor in one dog. The craniomedial acrylic connecting column simplified application of this modified type 1(a) configuration to the humerus by reducing the number of clamps required; the acrylic column also facilitated contouring of the cranlomedial connecting column to the brachium and was readily extended proxlmally to engage the intramedullary pin. In addition, the acrylic connecting column allowed placement of intramedullary pins of varying diameter.     

Surgical repair of radial carpal bone fractures in two racehorses

A 3-year-old Standardbred gelding (Case 1) and a 2-year-old Thoroughbred gelding (Case 2) were referred for surgical evaluation of a left radial carpal bone (RCB) fracture, sustained during training. Clinical findings at the time of initial examination included a palpable effusion within the left middle carpal joint in both horses and marked signs of pain and reduced range of motion on flexion of the affected carpus. In both horses, the RCB fracture was evident on the following radiographic views of the carpus: dorsolateral–palmaromedial oblique (30° off lateromedial) and flexed lateromedial. An additional loose wedge-shaped osteochondral fragment at the proximal articular surface of the RCB could be seen in Case 2. Both horses underwent surgical reduction and repair of the fracture between 1 and 2 days following the initial injury, which consisted of arthroscopic removal of any intra-articular osteochondral fragments, and arthroscopic assisted-interfragmentary compression via a standard dorsomedial and dorsolateral approach to the antebrachiocarpal joint (ACJ) and middle carpal joints (MCJ). The two horses returned to function as racehorses, 6 months (Case 1) and 16 months (Case 2) after surgery. The RCB is a relatively uncommon site for large carpal fractures in horses. The clinical presentation and findings from this report were similar to that of third carpal bone (C3) slab fractures, confirming that surgical repair is indicated in selected cases of RCB fractures.     

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.     

Use of an external fixator to correct a wry nose in a yearling

Wry nose is a rare condition. The resultant deviation of the nasal septum and maxilla/premaxilla often complicates deglutition and respiration. Traditional treatment consists of internal fixation with pins after an osteotomy and a rib graft. A 17‐month‐old Arab yearling was presented for evaluation of deviation of the maxilla and nasal septum. This deviation was managed using an external fixation device after bilateral osteotomy of the maxilla/premaxilla and reduction of the deviation. Partial resection of the nasal septum by a dorsal approach was also performed. The dental malocclusion and respiratory noise were corrected.     

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.     

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.     

Use of an external ring fixator for correction of an acquired angular limb deformity in a donkey

Numerous techniques for surgical correction of angular limb deformities in horses involving an osteotomy of the affected bone and stabilization with an internal fixation device have been described. However, because the osteotomy typically has to be performed at the level of the physis, leaving little bone between the physis and the nearest joint, stabilizing the osteotomy by use of internal fixation devices may be difficult. In horses with severe chronic angular limb deformities, the amount of soft-tissue contracture may make it impossible to correct the deformity during a single procedure without causing stretch injuries to the adjacent tendons and neurovascular structures. Adjustable external ring fixators incorporating hinged rods on 1 side of the limb and an angular motor assembly on the other may be useful for treatment of severe chronic angular limb deformities in younger equids, because they allow for gradual correction of the deformity.     

Technique for arthroscopic repair of third carpal bone slab fractures in horses

A technique involving internal fixation guided by arthroscopy was used to repair third carpal slab fractures in 23 horses. The technique allowed good reduction and compression of the fractures, with minimal surgical trauma. Ten of 17 horses with a 6-month or longer follow-up have returned to race successfully.     

Healed long-bone fractures in wild birds

AIM: To build a profi le of the oral lesions that occur in sheep in New Zealand that need to be considered within the differential diagnosis of foot-and-mouth disease.

METHODS: Lesions of the anterior lips and gums of sheep were surveyed in two abattoirs, photographed, and described grossly and histopathologically.

RESULTS: A sequence of lesions in order of age and stage of healing are described and illustrated, and their pathogenesis discussed. Lesions of the midline of the lips and gums of traumatic or irritant aetiology were common, and the prevalence was higher in adult sheep than in lambs.

CONCLUSIONS: The majority of lesions observed appeared to be primarily of traumatic aetiology. They probably arose from the fright/flight response behaviour of sheep, resulting in the mouth impacting against wire fences or yard railings while being handled. A smaller percentage of lesions may have been due to abrasive or irritant feed or soil. The presence of plant material and bacteria in lesions delayed healing and contributed to the formation of ulcers.