Use of a dynamic compression plate and a cable cerclage system for repair of a fracture of the radius in a horse

A pregnant 9-year-old Peruvian Paso mare was evaluated because of a fracture involving the left radius. On examination, grade IV/V lameness of the left forelimb was observed; radiography of the limb revealed a longitudinal oblique displaced fracture that extended from the caudal cortex of the radial mid-diaphysis into the humeroradial joint. To minimize the development of degenerative joint disease in the humeroradial joint, repair with internal fixation was recommended. A dynamic compression plate was applied to the cranial aspect of the radius; three 2-mm stainless steel cable cerclages were positioned around the mid- and proximal diaphysis. The horse was maintained in a sling for 8 to 12 hours daily for 3 weeks after surgery. Five months after surgery, the mare had foaled without complications, and grade I/V lameness during trotting only was observed. The combination of 1 dynamic compression plate and cable cerclage may provide satisfactory stabilization of this type of fracture in small to medium-sized horses.     

Fracture healing after stabilization with intramedullary xenograft cortical bone pins: a study in pigeons

OBJECTIVE: To investigate the effectiveness of intramedullary xenograft cortical bone pins compared with stainless steel Kirschner wire for the repair of a standardized avian humeral fracture. STUDY DESIGN: Prospective randomized study. SAMPLE POPULATION: Thirty mature pigeons (Columba livia). METHODS: Birds were randomly assigned to 3 groups. Transverse mid-diaphyseal humeral fractures were created in 1 humerus in each bird. Fractures were stabilized with intramedullary ostrich or canine xenograft cortical bone pins or Kirschner wire. Radiographic, histological, and biomechanical assessments were used to compare fracture healing 6 weeks after fracture stabilization. The contralateral humerus of each bird was used as a control. RESULTS: All fractures healed regardless of intramedullary pin type. There were no statistically significant biomechanical differences among groups or within groups. Xenograft cortical bone pins induced a mononuclear inflammatory reaction that did not impair bone healing. Bones stabilized with intramedullary cortical bone pins had more periosteal callus and inflammation at the fracture site than bones stabilized with stainless steel Kirschner wires. CONCLUSIONS: Intramedullary xenograft cortical bone pins, derived from mammalian or avian sources, appear to represent an alternative for the repair of avian humeral fractures. CLINICAL RELEVANCE: Intramedullary xenograft cortical bone pins are biodegradable and may reduce the need for additional surgery to remove implants after fracture healing.     

Use of a Medial Bone Plate for Repair of Radius and Ulna Fractures in Dogs and Cats: A Report of 22 Cases

Objective —This study evaluates the technique of medial bone plating in the repair of radius fractures in dogs and cats.
Study Design —A retrospective study was made of patients diagnosed with fractures of the radius that were stabilized by application of a bone plate to the medial side of the bone.
Animal Population —Sixteen client-owned dogs and 4 client-owned cats. The animals' ages varied from 5 months to 8 years, and their weight varied from 1.3 to 49 kgs.
Methods —Animals were evaluated using radiography or client assessment, or both.
Results —Medial plate application was technically easier to do than cranial plate application, the technique avoided the extensor tendons, and permitted greater versatility in the selection of smaller plates for the fixation of distal radius fractures. All fractures repaired by this method healed with no postoperative complications.
Conclusions —Medial plate application may be used for osteosynthesis of distal or middiaphy-seal radius fractures. Further studies are needed to evaluate the use of this technique in morphologically complex fractures. In patients with fractures of the proximal radius, cranial plate application is considered more appropriate.
Clinical Relevance —Medial plating of radial fractures has significant advantages compared with conventional plate application; it provides the surgeon with an alternative method of fixation for selected radius fractures in dogs and cats.     

犬污染骨异位寄养再回植的影像学评估

[目的]探讨犬游离长段桡骨通过寄养在血运丰富的隐静脉旁使其血管化来修复开放性骨折造成的骨缺损的可行性。[方法]选取12只成年健康犬随机分为实验组与对照组,2组分别截取右侧前肢桡骨中段约15 mm的桡骨骨段。模拟车祸环境,将截取的长段桡骨放置于外界泥土中1 h,取回的骨块用大量生理盐水冲洗,并放置在10%聚维酮碘中浸泡5 min,之后使用生理盐水冲洗1 min,沥干备用。实验组将其包埋在血管丰富的隐静脉处,对照组放置于-80℃低温无菌保存。8周后取出骨块,植回原位修复犬桡骨骨缺损。回植后第6、12周观察桡骨的大体形态。第4、8、12周通过X射线观察修复效果,使用Lane-Sandhu X线评分标准进行评分。[结果]在同一时间段内,实验组桡骨骨缺损修复的效果均好于对照组。[结论]通过寄养血管化的长段骨和低温保存长段骨均可修复犬桡骨骨缺损,与-80℃保存的骨块相比血管化的长段骨具有愈合时间短、骨吸收少的优点。     

Dual-energy X-ray absorptiometry measurement of bone-mineral density in the distal aspect of the limbs in racing Greyhounds

OBJECTIVE: To determine those bones in the distal aspect of the limbs of Greyhounds with fatigue fractures that have the greatest left-to-right differences in bone-mineral density (BMD). SAMPLE POPULATION: Limbs obtained from 20 Greyhounds. PROCEDURE: Dual-energy x-ray absorptiometry (DXA) of the distal aspect of each limb and isolated bones from 10 dogs with a fracture of the central tarsal bone (CTB) of the right pelvic limb was performed. High-resolution scanning was performed on excised bones, and BMD measurements of CTB also were obtained from limbs of dogs without a CTB fracture. RESULTS: The BMD of the accessory carpal bone and calcaneus was not significantly different from the BMD of those bones in the contralateral limb. Although BMD of the CTB of the entire right pelvic limb and isolated bones from dogs with a CTB fracture was lower, compared with values for the entire left pelvic limb, values for isolated CTB from dogs without a CTB fracture were not significantly different. Metacarpal or metatarsal and thoracic or pelvic limb significantly affected BMD for measurements of the entire limb and isolated bones. Left-to-right differences in BMD were greatest for metacarpal 5. CONCLUSIONS AND CLINICAL RELEVANCE: Asymmetric adaptive remodeling of metacarpal 5 can be detected by DXA. The potentially confounding effects of CTB fracture and unknown racing history made it difficult to interpret BMD changes in the CTB of these specimens. Densitometry could be developed as an in vivo assessment for risk of fractures in racing Greyhounds.     

Dual-Energy X-Ray Absorptiometry and Force-Plate Analysis of Gait in Dogs With Healed Femora After Leg-Lengthening Plate Fixation

Dual-energy x-ray absorptiometry was used to measure bone mineral density of four regions in healed femora of nine dogs after fracture fixation with a leg-lengthening plate. Six to 85 months (mean, 46 months) after surgery, the bone mineral density of healed femora was not significantly different from the contralateral uninjured femora ( P >.05; power = 0.8 at Δ= 15%). Radio-lucencies around the proximal screws, apparently associated with screw loosening, were seen on radiographic views of the healed femora of three dogs. In one of these dogs, one screw in the proximal metaphysis had broken. Force-plate analysis of gait was also performed on dogs at the time of bone mineral density measurement. Peak vertical force was decreased in the pelvic limb with the healed fracture compared with the contralateral unoperated limb ( P < 0.05). Clinically apparent lameness in three dogs did not appear to be associated with altered bone mineral density and may have been caused by hip osteoarthritis, a nondisplaced hairline diaphyseal fracture, and screw loosening in conjunction with extensive post-traumatic soft tissue injury.     

Biomechanical characteristics of allogeneic cortical bone pins designed for fracture fixation.

The biomechanical characteristics of 1.2 mm diameter allogeneic cortical bone pins harvested from the canine tibia were evaluated and compared to 1.1 mm diameter stainless steel pins and 1.3 mm diameter polydioxanone (PDS) pins using impact testing and four-point bending. The biomechanical performance of allogeneic cortical bone pins using impact testing was uniform with no significant differences between sites, side, and gender. In four-point bending, cortical bone pins harvested from the left tibia (204.8 +/- 77.4 N/mm) were significantly stiffer than the right tibia (123.7 +/- 54.4 N/mm, P = 0.0001). The site of bone pin harvest also had a significant effect on stiffness, but this was dependent on interactions with gender and side. Site C in male dogs had the highest mean stiffness in the left tibia (224.4 +/- 40.4 N/mm), but lowest stiffness in the right tibia (84.9 +/- 24.2 N/mm). Site A in female dogs had the highest mean stiffness in the left tibia (344.9 +/- 117.4 N/mm), but lowest stiffness in the right tibia (60.8 +/- 3.7 N/mm). The raw and adjusted bending properties of 1.2 mm cortical bone pins were significantly better than 1.3 mm PDS pins, but significantly worse than 1.1 mm stainless steel pins (P < 0.0001). In conclusion, cortical bone pins may be suitable as an implant for fracture fixation based on initial biomechanical comparison to stainless steel and PDS pins used in clinical practice.     

Pasteurized tumoral autograft and adjuvant chemotherapy for the treatment of canine distal radial osteosarcoma: 13 cases

OBJECTIVE: To report outcome in 13 dogs with distal radial osteosarcoma, without evidence of metastasis, treated by a combination of adjuvant chemotherapy and a pasteurized autograft limb-sparing procedure. STUDY DESIGN: Prospective clinical study. ANIMALS: Thirteen dogs with distal radial osteosarcoma. METHODS: Limb-sparing procedure was performed using an autograft from the excised tumoral segment, pasteurized at 65 degrees C for 40 minutes. Adjuvant chemotherapy (cisplatin or cisplatin and doxorubicin) was administered in all dogs. RESULTS: Mean and median survival times were 531 and 324 days, respectively (range, 180 to 1,868 days). Overall survival was 100% at 6 months, 50% at 12 months, 44% at 18 months, and 22% at 24 months. Lung metastasis occurred in 5 (38%) dogs. Observed complications were local recurrence (2 dogs, 15%), allograft infection (4 dogs, 31%), and implant failure (3 dogs, 23%). Limb function was good in 12 dogs (92%) and fair in 1 dog. CONCLUSIONS: Pasteurized bone autograft derived from the tumoral bone segment was an effective alternative to cortical bone allograft for limb sparing in canine distal radial osteosarcoma, in terms of feasibility, pattern of healing, complications, and survival. CLINICAL RELEVANCE: Use of a pasteurized bone autograft eliminates the need for a canine bone allograft bank and has the added advantage of good fit to the recipient site.     

Principles of uniapical and biapical radial deformity correction using dome osteotomies and the center of rotation of angulation methodology in dogs

OBJECTIVE: To describe the normal anatomic axis of the canine radius in 2 planes (frontal, sagittal), and report the use and efficacy of dome osteotomies for acute correction of canine antebrachial deformities. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Normal antebrachii (n = 20) radiographs were used as a reference, and 7 dogs with 9 radial angular limb deformities that were corrected by use of dome osteotomies. METHODS: Orthogonal radiographs of 20 normal antebrachii were used to determine normal ranges of frontal (FPA) and sagittal plane anatomic axes (SPA). Pre and postoperative radiographs of 7 dogs (9 radii) that had surgical correction of radial angular limb deformities by dome osteotomies were reviewed. Success at deformity correction into established normal ranges and to the normal contralateral side, if present, was determined. RESULTS: Normal ranges were FPA, 0-8 degrees and SPA, 8-35 degrees . There were 4 biapical and 5 uniapical deformities. FPA and SPA were corrected into normal range in 66% and 78% of affected limbs, respectively; however, only 44% of radii were corrected into normal ranges in both planes. CONCLUSIONS: Ranges for normal canine radial axes can be used as goals for angular limb correction when there is bilateral angular deformity. The dome osteotomy technique is advantageous in certain conditions for biplanar deformity correction. CLINICAL RELEVANCE: Dome osteotomies can be used to correct radial deformities in the frontal and sagittal planes, with certain advantages, but are heavily reliant on appropriate preoperative planning.     

Biomechanical comparison of cortical radial graft versus ulnar transposition graft limb-sparing techniques for the distal radial site in dogs

OBJECTIVE: To compare the biomechanical properties of radial graft (RG) versus ulnar transposition graft (UTG) limb-sparing techniques in the dog. STUDY DESIGN: Cadaveric study. ANIMALS: Six pairs of normal canine thoracic limbs. METHODS: In each pair of limbs, 1 limb was subjected to the RG technique and the other to the UTG technique. Limbs were tested in axial loading until failure. Modes of failure and biomechanical properties were compared between the 2 groups. Percent coverage of the metacarpal bone by the plate was retrospectively compared between the limbs that failed by fracture of the metacarpal bones and those that did not. RESULTS: RG limbs had significantly greater stiffness, yield load, maximum load, maximum energy, and post-yield energy. All UTG limbs failed by cranial bending of the plate. Half of the RG limbs failed by caudal bending of the plate and half by fracture of the third metacarpal bone at the distal end of the plate. Limbs with <80% plate coverage of the metacarpal bone were significantly more likely to fail by metacarpal fracture. CONCLUSIONS: The RG technique was biomechanically superior to the UTG technique under the conditions studied. At least 80% plate coverage of the metacarpal bone should be achieved. CLINICAL RELEVANCE: Exercise restriction and coaptation bandages should be considered for patients undergoing the UTG technique to minimize potential biomechanical complications.     

Signalment differences in bone mineral content and bone mineral density in canine appendicular bones. A cadaveric study.

The objective was to determine signalment-related differences in bone mineral content (BMC) and bone mineral density (BMD) in dogs. Unilateral appendicular bones were harvested from 62 canine cadavers. Mid-diaphyseal regions of interest (ROIs) were scanned using a Hologic DXA device Braincon, Vienna, Austria). BMC and BMD were calculated within this region. Middle-aged dogs (3-10 years) revealed the highest BMC and BMD levels. Mean BMC and BMD were higher in males compared to females. Furthermore, body-weight of the male dogs was significantly higher compared to the females (P < 0.0001). Body weight and bone length were significantly associated with BMC and BMD (P < or = 0.023) in all bones but the radius. These data suggest that BMC and BMD appear to be highest in male large-breed dogs with a body weight greater than 30 kg. These results may help determine risk factors in fracture development and healing.     

Pantarsal arthrodesis with a customised medial or lateral bone plate in 13 dogs

Pantarsal arthrodesis was performed in 12 dogs using a customised medial bone plate, and in one using a lateral bone plate. The dogs' ages ranged from 14 months to 144 months (median 30 months) and their bodyweights ranged from 7 to 66 kg (median 32 kg). Before the surgery they had been lame on a pelvic limb for between one and 16 months (median eight months). In eight of the dogs the fixation of the plate was augmented with a calcaneotibial positional screw, and in one of them with a talocrural lag screw. A cranial half cast was applied to 12 of the dogs and an external skeletal fixator to the other for six to eight weeks. Five complications were recorded in four of the dogs. Between 29 and 156 weeks postoperatively the clinical outcome was graded as excellent in six dogs, good in six dogs and fair in the other.     

The Effects of Cerclage Wiring on the Immature Canine Diaphysis A Biomechanical Analysis

When cerclage wiring is used in skeletally immature dogs, the wires become imbedded in the cortical bone due to radial appositional bone growth.
Six groups of five dogs each received one or two extraperiosteal cerclage wires at the mid-diaphysis of the left femur at the age of five months. Ten dogs were killed immediately, ten dogs were killed at eight weeks postoperatively, and ten at twelve weeks. Both femora from each animal were collected and subjected to torsional loading to failure within.5 seconds. The maximum torque, shear stress, energy absorption, angular deformation, and torsional stiffness were determined and subjected to í test analysis.
Application of the wires predictably caused an increase in weight and cortical bone thickening at the implant site, which was primarily due to endosteal bone deposition in the 8-and 12-week groups. The 8-and 12-week wired bones were stiffer and failed at a lower angular deformation than did their corresponding control femurs, but the zero-time bones did not show this tendency. Significantly less shear stress accumulation and energy absorption at failure were present In the 8-and 12-week implants, but no difference was seen in the zero-time femora. The 8-week groups showed a greater difference between the wired and control femurs than did the 12-week groups. No significant difference was found between one-and two-wire implants in the study.
The results indicate that confinement of dogs with clinically wired fractures of immature canine femurs should extend past eight weeks.     

Loss of implant-bone interface following distal radial locking-plate endoprosthesis limb-sparing surgery in a dog

An eight-year-old, neutered female Rottweiler was presented with lameness of seven days duration. Radiographs were consistent with a distal radial bone tumour. Limb-sparing surgery was performed using a commercially available endoprosthesis with a locking bone plate. Histopathological examination of the resected bone revealed an intraosseous fibrosarcoma, and postoperative adjuvant chemotherapy was initiated three weeks after surgery. Despite initial satisfactory limb function, lameness worsened four months after surgery. Radiographs revealed large areas of bone lysis around the proximal and distal screws, leading to significant resorption of the radius and radial carpal bone with subsequent construct failure. Further treatment was declined by the owner and the dog was subsequently euthanased. This case illustrates that implant failure is not necessarily averted by the use of locking (compared with non-locking) implants combined with an endoprosthesis to treat distal radial tumours in dogs.     

APPROACHES FOR ULTRASONOGRAPHIC EVALUATION OF LONG BONES IN THE DOG

The objective of this study was to identify access portals for ultrasonographic evaluation of canine long bones (humerus, radius, ulna, femur, and tibia). A 7.5 MHz linear transducer was used in five medium-sized dogs (range of 25-35 kg body weight). Good approaches could be identified for all long bones. For the proximal humerus, a cranial portal, and the distal humerus, a lateral portal is suggested. For the radius and ulna, a craniolateral approach seemed to be the best. In the hindlimb, a medial approach for the femur and a craniolateral approach for the tibia were the most effective approaches.     

Thoracic wall and pulmonary trauma in dogs sustaining fractures as a result of motor vehicle accidents

The records of 267 dogs seen at the University of Minnesota Veterinary Teaching Hospital for fractures resulting from motor vehicle accidents were examined to determine the prevalence and types of thoracic wall and pulmonary trauma associated with such cases. Results were analyzed for type and prevalence of thoracic wall and pulmonary injury, and for the prevalence of such injury in dogs with and without extrathoracic injury, in dogs with fractures of single vs multiple bones, in dogs with single fractures of specific bones, in dogs with fractures in the cranial vs the caudal one half of the body, and in dogs with fractures ipsilateral vs contralateral to thoracic injury. The overall prevalence of thoracic wall and pulmonary trauma was 38.9%; pulmonary contusions, pneumothorax, and fractured ribs were the most common injuries. More than 1 type of thoracic wall or pulmonary injury was diagnosed in 57.7% of the cases. Of the dogs with thoracic injury, 24% also had extrathoracic injuries; 16.5% of dogs without thoracic injury had extrathoracic injuries, not including fractures. Of the dogs with fractures of 1 bone, 36.3% had thoracic injuries. Of the dogs with fractures of more than 1 bone, 42.3% had thoracic injuries. The prevalence of thoracic wall and pulmonary trauma was significantly associated with the site of the fracture (cranial vs caudal and ipsilateral vs contralateral); significant association with the specific bone fractured was also seen for some fractures.     

Evaluation of plate luting, using an in vivo ovine osteotomy model

Bilateral, midshaft metacarpal osteotomies were performed in 11 sheep and bilateral, midshaft radial osteotomies were performed in 7 sheep. The lesions were repaired with bone plates. One of each pair of plates was luted with polymethylmethacrylate and all screws were tightened uniformly with a torque screwdriver. Sheep were allowed unrestricted exercise after surgery. At 8 weeks, 10 of 11 sheep with metacarpal osteotomies were sound and both osteotomies were healing. Seven were lame on the limb with the unluted plate during the first 3 weeks; 4 were never lame on either limb. The screws of the unluted plates were significantly (P less than 0.01) looser at 8 weeks than those in the luted plates. All of the sheep with radial osteotomies were lame in the limb with the unluted plate. Four of 7 sheep had overt loosening of the unluted plates. One sheep only had mild screw loosening with continued alignment of the osteotomy. Two of 7 sheep fractured the radius with the luted plate; these 2 sheep were lame in the limb with the unluted plate and were using the limb with the luted plate vigorously. Excluding the 2 sheep with fractures, all had substantially more screw loosening in the unluted plate. Histologically, there were no discernible differences in the vascularity or porosity of the bone under the luted vs the unluted plates. The only adverse consequence of the luting technique was introduction of a small amount of polymethylmethacrylate into the osteotomy gap in 5 bones.     

小型犬尺桡骨,股骨远端骨折的钢板植入及取出手术

本文对小型犬尺桡骨和股骨远端骨折实施了钢板植入和愈合后钢板的取出手术。由于小型犬骨骼细,找不到合适的钢板。我们利用现有的材料根据骨折的具体情况,进行了钢板植入手术的尝试均取得了成功。     

LOOSENING OF TRANSOSSEOUSLY PLACED ANTEBRACHIAL SCREWS IN TWO DOGS

Radius and ulna fractures in two dogs were repaired by application of a bone plate to the cranial surface of the radius. In both dogs, two screws were placed through the radius and into the ulna. Return of function and bone healing occurred as expected; however, return of lameness at 5 and 7 months postoperatively was attributed to loosening of the transosseous screws. The lameness resolved following implant removal. Loosening of only the transosseous screws could have resulted from the normal motion between the radius and ulna.