Short-term outcomes and complications of 65 cases of porous TTA with flange: a prospective clinical study in dogs.

BACKGROUND: Cranial cruciate ligament rupture (CrCLR) is the most common orthopaedic cause of lameness in the hind limb in dogs. Many surgical treatments have been described, but tibial tuberosity advancement (TTA) is one of the most commonly used today. Since it was first described, TTA has evolved to reduce major complications and to arrest the progression of osteoarthrosis. The aim of this study was to assess a surgical technique called Porous TTA with flange prospectively. This study was performed in 61 dogs that underwent 65 Porous TTA with flange procedures, to validate it as an alternative CrCLR treatment. Complications and clinical outcomes (pain, lameness, weight bearing, flexion, extension, crepitation and atrophy) were reported over 3 months, i.e. at 3, 6 and 12 weeks postoperatively. RESULTS: The results showed a positive clinical outcome, a minor complication rate of 47.69% at the first review 3 weeks postoperatively, 10.77% at the second one (6 weeks after the surgery) and 4% at the third one (at 12 weeks). Major complications were observed only at the last review, with one case that had an infection requiring implant removal; this represented 1.5% of cases. Variables evaluated for a relationship with complication scores and improvement were body condition score, sex, age, breed, body weight, breed size, side of the affected limb, traumatic anamnesis and time of lameness before surgery. No relationship was detected. CONCLUSIONS: Clinical outcomes and complications show that Porous TTA with flange is an efficient alternative for surgical treatment of CrCLR in dogs.

Surgical treatment of disk-associated wobbler syndrome by a distractable vertebral titanium cage in seven dogs.

OBJECTIVE: To evaluate a distractable titanium cage for the treatment of disk-associated wobbler syndrome (DAWS). STUDY DESIGN: Prospective study. ANIMALS: Dogs (n = 7) with DAWS. METHODS: After total discectomy of C5-C6 and C6-C7, the median part of the vertebral body of C6 was removed with preservation of the lateral walls and dorsal cortex. The removed cancellous bone was collected. The implant was placed in the bony defect of C6. After placement, the titanium cage was distracted and affixed by 4 screws. Finally, the implant was filled and covered with cancellous bone. Dogs had follow-up examinations at 1, 3, 6, 12, and 24 months. Six months after surgery, cervical radiographs and computed tomography (CT) were performed. RESULTS: Although no intraoperative complications occurred, correct placement of the cage was technically challenging. Revision surgery was necessary in 2 dogs because of implant loosening and aggravation of vertebral tilting. All dogs improved after discharge from the hospital. In 1 dog, recurrence of clinical signs caused by articular facet proliferation at an adjacent intervertebral disk space occurred. Radiographs at 6 months demonstrated cage subsidence in 4 dogs. In all dogs, CT was suggestive for fusion of the bone graft with the vertebral body. CONCLUSIONS: Although results are promising, technical adaptations will be necessary to make this specific surgical technique, designed for humans, suitable for routine use in dogs.

Theoretical discrepancy between cage size and efficient tibial tuberosity advancement in dogs treated for cranial cruciate ligament rupture.

OBJECTIVES: To calculate the difference between the desired tibial tuberosity advancement (TTA) along the tibial plateau axis and the advancement truly achieved in that direction when cage size has been determined using the method of Montavon and colleagues. To measure the effect of this difference on the final patellar tendon-tibial plateau angle (PTA) in relation to the ideal 90°. METHODS: Trigonometry was used to calculate the theoretical actual advancement of the tibial tuberosity in a direction parallel to the tibial plateau that would be achieved by the placement of a cage at the level of the tibial tuberosity in the osteotomy plane of the tibial crest. The same principle was used to calculate the size of the cage that would have been required to achieve the desired advancement. The effect of the difference between the desired advancement and the actual advancement achieved on the final PTA was calculated. RESULTS: For a given desired advancement, the greater the tibial plateau angle (TPA), the greater the difference between the desired advancement and the actual advancement achieved. The maximum discrepancy calculated was 5.8 mm for a 12 mm advancement in a case of extreme TPA (59°). When the TPA was less than 31°, the PTA was in the range of 90° to 95°. CLINICAL SIGNIFICANCE: A discrepancy does exist between the desired tibial tuberosity advancement and the actual advancement in a direction parallel to the TPA, when the tibial tuberosity is not translated proximally. Although this has an influence on the final PTA, further studies are warranted to evaluate whether this is clinically significant.

Ex vivo comparison of a novel tapered-sleeve and traditional full-limb transfixation pin cast for distal radial fracture stabilization in the horse.

Distal radial fractures in adult horses are examples of long-bone fractures that are not always amenable to internal fixation. These fractures are often open, contaminated, severely comminuted, and located adjacent to the antebrachiocarpal joint. There have been few studies to improve upon the methods of stabilization of this type of fracture. External coaptation incorporating transfixation pins is one method that has been used to stabilize distal radial fractures in horses (1-3). The purpose of this preliminary study was to compare the load to failure in simulated weight-bearing of a novel tapered-sleeve transfixation pin cast (TSTPC) (4) with the traditional transfixation pin cast (TPC) in an ex vivo distal radial fracture model. Ten adult equine cadaveric forelimbs were randomly placed into a TPC group (n = 5) or a TSTPC group (n = 5). An oblique distal radial osteotomy was created prior to application of fibreglass cast material. The limbs were loaded in a single cycle to failure in simulated weight-bearing using an axial load. The mean load to failure for the TSTPC group (35,814 N) was significantly greater than in the TPC group (22,344 N) (p = 0.003). Tapered sleeves in conjunction with TPC warrant further investigation because they may prolong the life of the fixation, prevent or diminish fractures through the pin sites, and increase the load capacity of external coaptation used to stabilize equine fractures.

Mechanical analysis of fixation methods for anterior cruciate ligament reconstruction with hamstring tendon graft. An experimental study in sheep knees.

This study evaluates the structural properties of the femur-anterior cruciate ligament (ACL) graft-tibia complex, comparing different graft fixation techniques in sheep knees. Four fixation devices were tested both for femoral fixation (Transfix, absorbable screw, RCI screw and Linx-HT) and tibial fixation (bone plug with metal screw, absorbable screw with staple, RCI screw and cancellous screw with spiked washer). The graft used for ACL reconstruction was fresh ovine doubled Achilles tendon (DAT). Femurs and tibias were tested separately. Two mechanical test series were performed on the specimens: a load-to-failure test and a cyclic loading test. On the femoral side, transcondylar screw showed the greatest fixation strength and stiffness and the lowest elongation at cyclic loading. Tibial fixation complexes seemed to have poorer structural properties in comparison to femoral fixation. Among the tibial fixation devices, absorbable screw with staple fixation showed the greatest strength and stiffness. Spiked washer fixation showed the greatest elongation under cyclic loading.

In vitro mechanical properties of different equine hoof wall crack fixation techniques.

Hoof wall cracks need mechanical stabilisation to allow healing. Common techniques are fixation with screws, wires and plates or bonding of a patch across the crack. An in vitro system to determine the shear properties of equine hoof crack repairs is described. The force and displacement at yield, stiffness and ultimate force were determined for 4 repair techniques based on an acrylic material, polyurethane patch attached with cyanoacrylate adhesive, steel plate attached with screws and a transverse metal bar cut into the hoof wall. The cyanoacrylate bonded patch repair had lower values for all parameters measured (n = 8, P<0.05) and the other 3 repairs had similar mechanical properties. This study demonstrates that acrylic adhesive repairs can resist similar shear forces to traditional screw plate repairs without risk of penetrating into the sensitive structures of the foot. The transverse bar mounted across the crack had similar resistance to shear as the much larger screw plate and plain bonding repair techniques. This novel technique may be a useful adjunct to other repair methods.

In vitro comparison of the standard short limb cast and three configurations of short limb transfixation casts in equine forelimbs.

Axial stability of equine oblique proximal phalangeal osteotomies with application of the standard short limb cast or 1 of 3 configurations of transfixation casts was determined in vitro. Transfixation cast methods included use of parallel pins, divergent pins, or parallel pins incorporating a metal walking bar. Displacement at the osteotomy was recorded for each limb at 4,448 N. Standard short limb casts provided significantly (P = 0.0002) less axial stability than did any form of transfixation cast. Significant differences were not found between the 3 transfixation casts.

In vitro comparison of transfixation and standard full-limb casts for prevention of displacement of a mid-diaphyseal third metacarpal osteotomy site in horses.

OBJECTIVE: To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses. SAMPLE POPULATION: 6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system. PROCEDURE: A 30 degrees osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that incorporated the pins was applied. An extensometer was positioned in the osteotomy site through a window placed in the dorsal aspect of the cast, and after removal of the screws, displacement was recorded while the limb was axially loaded to 5,340 N (1,200 lb). Pins were removed, and the standard full-limb cast was tested in a similar fashion. RESULTS: The transfixation cast significantly reduced displacement across the osteotomy site at 445 N (100 lb), 1,112 N (250 lb), 2,224 N (500 lb), and 4,448 N (1,000 lb), compared with the standard cast. CONCLUSION AND CLINICAL RELEVANCE: A full-limb transfixation cast provides significantly greater resistance than a standard full-limb cast against axial collapse of a mid-diaphyseal third metacarpal osteotomy site when the bone is placed under axial compression. Placement of full-limb transfixation casts should be considered for the management of unstable fractures of the third metacarpal bone in horses.

Cervical vertebral interbody fusion in the horse: a comparative study of bovine xenografts and autografts supported by stainless steel baskets.

A modified form of the Cloward technique for anterior cervical fusion in human beings was used in the application of different grafts for evaluation of their effectiveness in stabilizing equine cervical vertebrae. Results of bovine xenograft implants in 8 horses were compared with results of stainless steel baskets (SSB) packed with cancellous autogenous bone in 8 horses. Graft material was incorporated in all cases. Evidence of graft rejection was not present. Both forms of implants decreased the mobility of the intervertebral space in which they were implanted. A fibrous connective tissue union was prevalent after xenograft implantation. Osseous union was prevalent after implantation of the SSB. Reduction in range of motion was greatest at those sites with the SSB.

Conservative management of fractures of the mandibular condyloid process in three cats and one dog.

Three cats and 1 dog with fracture of the mandibular condyloid process and concomitant fracture(s) of the rostral portion of the mandible were treated successfully by wire fixation of the rostral mandibular fracture(s) and by conservative management of the mandibular condylar fracture. All animals regained satisfactory dental occlusion and normal, pain-free motion of the jaw. Fracture of the mandibular condyloid process is an infrequently diagnosed injury that usually occurs with other mandibular fractures. If satisfactory dental occlusion can be achieved by surgical stabilization of the noncondylar fractures, surgical repair of the mandibular condyloid fracture may not be necessary.

Tension band stabilization of fractures and luxations of the thoracolumbar vertebrae in dogs and cats: 38 cases (1993-2002).

OBJECTIVE: To determine the outcome of dogs and cats in which a tension band technique was used to stabilize traumatic fractures and luxations of the thoracolumbar vertebrae. DESIGN: Retrospective study. ANIMALS: 38 client-owned animals (22 dogs and 16 cats) weighing between 1.4 and 45 kg (3 and 99 lb). PROCEDURE: Medical records of cats and dogs that underwent tension band stabilization of thoracolumbar fractures and luxations at the University of Zurich between 1993 and 2002 were reviewed. The stabilization technique was a modification of a spinal stapling technique with a figure 8 hemicerclage wire placed in a tension band fashion across the lesion. Neurologic status, lesion location and type, and concomitant traumatic injuries were assessed from the medical records and preoperative radiographs. Clinical outcome and complications were determined through follow-up examinations or telephone conversations with the owners. RESULTS: Complete or satisfactory neurologic recovery was achieved in 30 (79%) patients. Seven patients were euthanatized (6 owing to poor neurologic recovery and 1 owing to implant failure), and 1 dog was managed at home despite paraplegia. Clinically, only 4 patients (11%) had evidence of implant or fixation failure; all were dogs weighing > 16 kg (35 lb). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the tension band technique may be appropriate for stabilization of fractures and luxations of the thoracolumbar vertebrae in cats and small- or medium-sized dogs. In larger dogs, fixation strength may be insufficient to stabilize certain fracture types and ancillary external or internal fixation methods may be needed.

Surgical treatment of grade IV patellar luxation in the neoambulatory dog.

A wire-suture method was used for correcting grade IV medial and lateral luxations of the patella. In seven operated stifles, the method resulted in a normal gait and minimal valgus and varus deformity of the distal femur and proximal tibia.

Treatment of fractures of the tibial tuberosity in the dog.

Of 27 dogs with fractures of the tibial tuberosity, 24 were treated by various methods of open reduction. Follow-up examination was obtained in 21 cases, and it was found that all but one fracture healed in 8 weeks. Tension band wiring and single interfragmentary screws were most commonly used; healing was similar in both groups.

Type I biplanar configuration of external skeletal fixation: application technique in nine dogs and one cat.

Mechanical attributes and techniques of applying the type I biplanar (quadrilateral) configuration of external skeletal fixation are reported. The apparatus was used clinically on 9 dogs and 1 cat with long bone fractures. Bony union occurred in these animals, but was slightly delayed in one. Return to clinical function of the limb generally was good to excellent. The instances of delayed union and poor clinical results are discussed to emphasize the use of good techniques of application and case selection.

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.

Treatment of cervical vertebral instability in the dog.

In a retrospective study, common neurologic signs and results of treatment of cervical vertebral instabilities were reviewed. In 16 large dogs, vertebrae C5 and C6 were most frequently malformed and unstable. Treatment was conservative in 3 dogs, 1 dog was not treated, and 12 dogs were treated surgically (dorsal decompressive laminectomy and wire stabilization of the articular facets in most cases). The 3 conservative treatments and 8 of the 12 surgical treatments were considered beneficial.

Evaluation of four techniques of cervical spinal fixation in dogs.

Four surgical techniques for immobilizing unstable cervical vertebrae were evaluated. These techniques included: (1) placing screws bilaterally through the articular processes, (2) placing wires bilaterally through the articular processes, (3) placing a bone screw through vertebral bodies, and (4) placing a bone plate on the ventral surface of adjacent vertebral bodies. Each technique was found to have certain advantages and disadvantages.

An expansion and compression technique for reducing and stabilizing proximal epiphyseal fractures of the tibia in foals.

Proximal tibial epiphyseal fractures in 2 foals were reduced and stabilized by expansion and compression between 2 transversely placed Steinman pins, one on each side of the fracture. A Charnley apparatus or turnbuckles placed between the pins on each side of the fracture provided the mechanical advantage for repositioning the fracture fragments and achieving rigid fixation during healing. A light cast was applied over the fixation apparatus, keeping the limb in an extended position. The cast and fixation apparatus were removed after 4 weeks. The technique allowed rapid healing and adequate ambulation. The foals had functional, straight hindlimbs 6 months after the fractures occurred.

Growth plate defects in foals.

Local disorders of bone growth form an important group of the orthopaedic problems that occur in foals. The recognition of the condition presented is essential so that the appropriate corrective measures may be instituted, and an accurate prognostication made. A knowledge of the applied anatomy of the growth plate is essential to the understanding of these cases. Consideration is given to epiphyseal separation and to angular deformity, from the point of view of diagnosis, prognosis and treatment.

The use of plastic plates for fixation of spinal fractures in the dog.

Plastic plates are a rapid and easy method to realign and stabilize the spinal column following a traumatic injury and may give greater bone-to-plate contact than metal plates. They distribute the pressure on the spinous processes over a larger surface area although plate slippage and spinous process fractures can occur as with any plate. Laminectomies should not be a routine procedure with plating but each patient should be evaluated individually and autogenous bone grafts may be used to advantage to promote fusion of vertebral bodies. In the two cases presented, the plastic plates achieved their purpose. However, it is essential that fusion of the vertebrae occurs before the plates slip or the spinous processes fracture.