Distraction osteogenesis at the site of neutral wedge ostectomy for angular limb deformity in the hind limb in 2 young dogs.

Our objective was to report the use of distraction osteogenesis at the site of angular limb deformity correction using external skeletal fixation for treatment of 1 femoral and 1 tibial angular limb deformity in 2 large-breed puppies. Medical records were reviewed from 2 dogs (a 7-month-old intact male golden retriever and a 4-month-old intact female German shepherd mixed breed) diagnosed with angular limb deformities and truncation of a pelvic limb. Surgical treatment consisted of neutral wedge ostectomy and distraction osteogenesis at the site of bone deformity with an external skeletal fixator (ESF). The surgical technique and postoperative period of distraction osteogenesis were reviewed along with postoperative complications and clinical outcomes after complete bone healing was evident radiographically. Both dogs had adequate bone formation during distraction osteogenesis and the ESFs remained intact and structurally stable. At ESF removal, femoral length had increased 2.6 cm for Dog 1 and tibial length increased 3.88 cm for Dog 2, distal femoral valgus improved 16.3 degrees for Dog 1, and tibial procurvatum improved 19.5 degrees and distal tibial valgus improved 6.2 degrees for Dog 2. At the last follow-up examinations, 5 mo (Dog 1) and 3 mo (Dog 2) postoperatively, both dogs were ambulating without any visible lameness. Key clinical message: Acute angular correction and subsequent distraction osteogenesis at the site of bone deformity and corrective ostectomy using an ESF enabled successful treatment of femoral (Dog 1) and tibial (Dog 2) truncation and angulation in 2 large-breed puppies. Optimal deformity correction and lengthening were achieved through distraction osteogenesis at the site of neutral wedge ostectomy, minimizing soft tissue dissection and risk for potential complications that can occur with bifocal deformity correction (i.e., correction of the deformity at 1 osteotomy/ostectomy and correction of bone length at another, remote osteotomy).

Ostéogenèse par distraction au site d'ostectomie en coin neutre pour déformation angulaire du membre postérieur chez 2 jeunes chiens. Notre objectif était de rapporter l'utilisation de l'ostéogenèse par distraction au niveau du site de correction de la déformation angulaire du membre par fixation squelettique externe pour le traitement d'une déformation angulaire fémorale et d'une déformation angulaire tibiale chez 2 chiots de grande race. Les dossiers médicaux ont été examinés concernant 2 chiens (un golden retriever mâle intact âgé de 7 mois et une femelle berger allemand intacte de race mixte âgée de 4 mois) diagnostiqués avec des déformations angulaires des membres et une troncature d'un membre pelvien. Le traitement chirurgical consistait en une ostéogenèse en coin neutre et une ostéogenèse par distraction au niveau du site de déformation osseuse avec un fixateur squelettique externe (FSE). La technique chirurgicale et la période postopératoire d'ostéogenèse par distraction ont été examinées ainsi que les complications postopératoires et les résultats cliniques après une guérison osseuse complète évidente radiographiquement.Les deux chiens présentaient une formation osseuse adéquate pendant l'ostéogenèse par distraction et les FSE restaient intacts et structurellement stables. Lors du retrait de le FSE, la longueur fémorale avait augmenté de 2,6 cm pour le chien 1 et la longueur tibiale de 3,88 cm pour le chien 2, le valgus fémoral distal s'était amélioré de 16,3 degrés pour le chien 1, le procurvatum tibial s'était amélioré de 19,5 degrés et le valgus tibial distal s'était amélioré de 6,2 degrés pour le chien 2. Lors des derniers examens de suivi, 5 mois (chien 1) et 3 mois (chien 2) postopératoires, les deux chiens marchaient sans aucune boiterie visible.Message clinique clé :La correction angulaire aiguë et l'ostéogenèse de distraction ultérieure au site de déformation osseuse et l'ostectomie corrective à l'aide d'un FSE ont permis un traitement réussi de la troncature et de l'angulation fémorale (chien 1) et tibiale (chien 2) chez 2 chiots de grande race. La correction et l'allongement optimaux de la déformation ont été obtenus grâce à l'ostéogenèse par distraction au site de l'ostectomie en coin neutre, minimisant la dissection des tissus mous et le risque de complications potentielles pouvant survenir avec la correction de la déformation bifocale (c'est-à-dire la correction de la déformation à 1 ostéotomie/ostectomie et la correction de la longueur de l'os à une autre ostéotomie distante).(Traduit par Dr Serge Messier).

Bifocal femoral deformity correction and lengthening using a circular fixator construct in a dog.

A 7 mo old male rottweiler was evaluated for a right hind limb lameness caused by malunion of a Salter-Harris type II fracture. Radiographs and computed tomography (CT) revealed that the right distal femur had valgus, procurvatum, external rotation, and was 35% (70 mm) shorter than the contralateral femur. Distal femoral wedge ostectomies were performed to acutely correct the angular and rotational deformities. Lengthening of the femur was accomplished by distraction osteogenesis performed over 53 days at a second, proximal diaphyseal osteotomy using a circular fixator construct. This bifocal approach yielded approximately 30 mm of femoral lengthening and a confluent column of regenerate bone that bridged the distraction gap. When evaluated 14 mo after surgery, the dog held the right hip, stifle, and hock in a slightly extended posture when standing and had a subtle asymmetric hind limb gait. The stride of the right hind limb was slightly shortened with compensatory circumduction of the left hind limb during the swing phase of the stride.

Use of hinged circular fixator constructs for the correction of crural deformities in three dogs.

BACKGROUND: Hinged circular external skeletal fixator constructs are used to perform sequential correction of angular limb deformities, often with resultant limb segment lengthening, via distraction osteogenesis. Although there are several reports describing the use of these constructs for correction of antebrachial deformities in dogs, there is little information regarding their use on other limb segments. This report describes the use of hinged circular fixator constructs for the correction of acquired crural deformities in three skeletally immature dogs. CASE REPORTS: Two dogs had purely frontal plane deformities (one valgus, one varus) and the third dog had frontal (valgus) and sagittal (recurvatum) components to its deformity. At the time of long-term evaluation, frontal plane angulation relative to the contralateral limb improved from 40° to 22° of valgus, 30° to 5° of valgus, and 20° to 1° of varus in the three individual dogs. Tibial length discrepancies of 12% and 22% that were initially present in two dogs were improved to 6% and 10%, respectively, of the contralateral tibial length at the time of final evaluation; both dogs had compensatory growth of the ipsilateral femur and all dogs had an excellent functional outcome. CONCLUSION: These cases illustrate the value of using hinged circular fixator constructs for correction of crural angular deformities, particularly when length discrepancies of the tibia are present.

Femoral angular correction and lengthening in a large-breed puppy using a dynamic unilateral external fixator.

OBJECTIVE: To report treatment of a large-breed puppy with combined distal femoral valgus and length deficit caused by partial distal physeal closure. STUDY DESIGN: Clinical report. ANIMALS: Bernese Mountain Dog (4.5-month-old male). METHODS: The puppy was admitted for evaluation of a progressive severe left pelvic limb lameness (grade 3/4) of 6-week duration. Distal femoral valgus and severe length deficit deformity were treated by acute angular correction using a closing wedge ostectomy and progressive rapid-rate callus distraction using a dynamic, telescoping unilateral External Skeletal Fixator (ESF) designed for people. After acute angular correction and a 3-day latency period, a mean linear distraction rate of 3 mm/day was maintained for 3 weeks. The dynamic ESF (dESF) was removed at 4 weeks, after a 1-week consolidation phase. RESULTS: The dESF was stable and functional during distraction and bone healing. Distal femoral valgus conformation improved 50° (from 41° to 91°) and femoral length increased 42 mm at dESF removal (from 158 mm to 200 mm; 27%). After cessation of bone growth, no valgus and minimal (6%) length deficit were detected. At 4, 5, 6, 12, and 24 months after surgery, the dog was walking, trotting, and galloping normally. CONCLUSION: Acute angular correction and progressive rapid-rate callus distraction using a unilateral dESF allowed satisfactory treatment of combined distal femoral valgus and length deficit in a large-breed puppy.

Limb lengthening in three dogs using distraction rates without a latency period. Radius/ulna, tibia, femur.

OBJECTIVE: To report three clinical cases suffering from limb shortening secondary to monostotic physeal closure, in which distraction osteogenesis had been performed without a latency period and with high distraction rates. METHODS: Three dogs had limb lengthening performed, using an Ilizarov ring fixator in two dogs and a linear dynamic fixator in the other dog. Bone lengthening achieved for a radius/ulna was 27 mm at 2 mm per day , a tibia was 78 mm at 3 mm per day, and a femur of 45 mm was 3 mm per day . RESULTS: Complications related to pin loosening occurred in each case, thus requiring surgical corrective procedures, but these did not affect the final outcome. Lateral bowing of the bar and bone and some musculo-cutendinous contracture occurred in the femur. Fixation frames were on for 12 weeks in Case 1, eight weeks in Case 2 and nine weeks in Case 3. All three of the cases had a good functional outcome. DISCUSSION: The faster rates of lengthening were not associated with any long-term deleterious soft tissue complications, but they were associated with pin loosening and bending of the bar. In each case there was excellent osteogenesis. CONCLUSIONS: From the results achieved in these three cases it can be concluded that a latency period prior to distraction osteogenesis may not be necessary. Also, distraction rates up to 3 mm per day can be used to shorten the time needed to achieve lengthening; however further studies are needed to investigate the high level of complications.

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.

Trauma-induced growth abnormalities of the distal radius in three cats.

Three immature cats with growth abnormalities of the distal radius secondary to trauma were presented between July 2001 and July 2003. Initial injuries included a Salter-Harris type II fracture of the distal radial physis in one cat, fractures of the styloid process of the ulna in two cats, and metacarpal fractures in one cat. The cats were between 3.5 and 4.5 months of age at the time of injury. Damage to the distal radial physis resulted in a variable degree of shortening of the radius in all cats. Asymmetrical closure caused widening of the lateral aspect of the radiocarpal joint space in two cats. Elbow incongruity was not observed. One cat was treated with osteotomies of the radius and ulna and realignment of the radius, stabilised with external skeletal fixation. Another was treated by ulnar ostectomy alone. Radius and ulna osteotomies and distraction osteogenesis of the radius were performed in the third cat. Clinical outcome was satisfactory in all three cases.

Complications of middiaphyseal radial ostectomy performed for treatment of premature closure of the distal radial physis in two dogs.

Middiaphyseal radial ostectomy was performed in 2 dogs that had premature closure of their distal radial physes. Complications included disuse osteoporosis, carpal hyperextension of the affected and contralateral limbs, degenerative joint disease involving the cubital and carpal joints, synostosis of the radius to the ulna, premature closure of the distal portion of the ulna, and failure to achieve normal limb length. Both dogs were lame after exercise.

Distraction osteogenesis using modified external fixation devices in five dogs.

Distraction osteogenesis was used to treat five dogs with limb deformities or limb shortening. The affected bones underwent osteotomy, and modified external fixators were attached. Complications included pin loosening, implant breakage, and soft-tissue contracture. Adequate limb length was attained in all cases, but clinical results varied from poor to excellent. Two dogs were not lame after the procedure, two dogs had improved function but were still lame, and one dog had complications necessitating amputation.

[Unequal femurs]. / Femores inaequales.

The femurs of a dog presented for lameness were found to be unequal in length. This was successfully treated by resection of the head of the femur. This patient was affected with rupture of the contralateral anterior cruciate ligament within six months.