Effect of tibial plateau leveling osteotomy on femorotibial subluxation: in vivo analysis during standing

OBJECTIVE

To assess the effect of tibial plateau leveling osteotomy (TPLO) on femorotibial subluxation during standing in dogs with cranial cruciate ligament (CrCL) insufficiency.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Fifteen dogs weighing 20-45 kg with unilateral complete CrCL insufficiency.

METHODS

Force-platform analysis, and lateral weight-bearing radiographs of the affected stifle were acquired preoperatively, 1, 3, and 6 months postoperatively. The distance between the origin and insertion of the CrCL (CrCL(d) ) was measured on each radiograph and compared between time points using ANOVA. Lateral radiographs of the non-weight-bearing affected stifle and weight-bearing contralateral normal stifle were acquired preoperatively, and CrCL(d) was compared with a paired t-test. Dogs were grouped according to medial meniscal status (intact or hemimeniscectomy) and CrCL(d) was compared within each group using ANOVA.

RESULTS

No difference was observed in CrCL(d) between the non-weight-bearing affected stifle and the contralateral stifle (P = .994). That is, femorotibial joint alignment in the affected stifle when non-weight-bearing was considered normal. Preoperatively in the affected stifle, CrCL(d) during weight-bearing was 6.3 ± 2.4 mm longer than normal (P < .001). Postoperative weight-bearing CrCL(d) in dogs with intact menisci at all time points was not statistically different from normal; CrCL(d) at 1 (P = .014) and 6 months (P = .005) postoperatively was longer than normal in dogs with hemimeniscectomy.

CONCLUSIONS

TPLO does not consistently resolve femorotibial subluxation during standing in dogs with CrCL insufficiency. The medial meniscus appears to be an important contributor to stability in stifles treated by TPLO.

Canine hip dysplasia: reviewing the evidence for nonsurgical management

OBJECTIVE

To systematically review the evidence available for nonsurgical management of hip dysplasia (HD).

STUDY DESIGN

Literature review.

METHODS

Databases (Pubmed, Veterinary Information Network) were searched for clinical studies on nonsurgical management of HD in dogs. The evidence in each study was reviewed and assigned a score (I-IV) based on previously reported levels of evidence.

RESULTS

Fourteen articles were identified that met the inclusion criteria, including 3 Level IV, 4 Level III, and 7 Level II studies. Methods of nonsurgical management reviewed included: activity restrictions, weight management, acupuncture, modulation of joint disease by polysulfated glycosaminoglycans, mesenchymal stem cell therapy, and extra corporeal shock wave therapy.

CONCLUSION

Weight management is an effective and important component of managing dogs with HD and associated osteoarthritis. Techniques that modulate the progression of joint disease may also be beneficial for treating dogs with HD. Further studies are needed to investigate other methods of managing HD such as hydrotherapy and physical rehabilitation.

Stabilization of juxta-physeal distal tibial and fibular fractures in a juvenile tiger using a hybrid circular-linear external fixator

OBJECTIVE

To report stabilization of closed, comminuted distal metaphyseal transverse fractures of the left tibia and fibula in a tiger using a hybrid circular-linear external skeletal fixator.

STUDY DESIGN

Clinical report.

ANIMAL

Juvenile tiger (15 months, 90 kg).

METHODS

From imaging studies, the tiger had comminuted distal metaphyseal transverse fractures of the left tibia and fibula, with mild caudolateral displacement and moderate compression. Multiple fissures extended from the fractures through the distal metaphyses, extending toward, but not involving the distal tibial and fibular physes. A hybrid circular-linear external skeletal fixator was applied by closed reduction, to stabilize the fractures.

RESULTS

The fractures healed and the fixator was removed 5 weeks after stabilization. Limb length and alignment were similar to the normal contralateral limb at hospital discharge, 8 weeks after surgery. Two weeks later, the tiger had fractures of the right tibia and fibula and was euthanatized. Necropsy confirmed pathologic fractures ascribed to copper deficiency.

CONCLUSION

Closed application of the hybrid construct provided sufficient stability to allow this 90 kg tiger's juxta-articular fractures to heal with minimal complications and without disrupting growth from the adjacent physes.

Fusion Podoplasty for the Management of Chronic Pedal Conditions in Seven Dogs and One Cat

Eight animals underwent fusion podoplasties for the treatment of chronic interdigital furunculosis (n=3), ectrodactyly (n=1), digit abnormalities associated with tendonectomy (n=1), redundant indertigital skin (n=1), conformational deformity (n=1), and necrotizing fasciitis of the paw (n=1). Median duration of bandaging was 14 days, and median duration of hospitalization was 5 days. Four dogs had dehiscence, which occurred at a mean time of 11 days after surgery. Clinical abnormalities necessitating podoplasty resolved in six animals and improved in two. Six animals had normal ambulation and two dogs had slight weight-bearing lameness after a median follow-up time of 29 mo. Fusion podoplasty may be recommended as a salvage procedure for the treatment of various chronic pedal diseases in dogs and cats.

Radiographic quantitative assessment of cranial tibial subluxation before and after tibial plateau leveling osteotomy in dogs

OBJECTIVE

To determine the influence of stifle joint flexion angle, cranial cruciate ligament (CrCL) integrity, tibial plateau leveling osteotomy (TPLO), and cranial tibial subluxation on the distance between the location of the origin and insertion of the CrCL (CrCL(d)) in dogs.

SAMPLES

4 pairs of pelvic limbs from adult dog cadavers weighing 23 to 34 kg. Procedures-Mediolateral projection radiographs of each stifle joint were obtained with the joint flexed at 90°, 105°, 120°, 135°, and 150°. Radiopaque markers were then placed at the sites of origin and insertion of the CrCL. Afterward, radiography was repeated in the same manner, before and after CrCL transection, with and without TPLO. Following CrCL transection, radiographs were obtained before and after inducing overt cranial tibial subluxation. Interobserver variation in measuring the CrCL(d) without fiduciary markers was assessed. The effect of CrCL integrity, cranial tibial subluxation, flexion angle, and TPLO on CrCL(d) was also determined.

RESULTS

Interobserver agreement was strong, with an intraclass correlation coefficient of 0.859. The CrCL(d) was significantly shorter (< 1 mm) at 90° of flexion; otherwise, flexion angle had no effect on CrCL(d). Cranial tibial subluxation caused a 25% to 40% increase in CrCL(d). No effect of TPLO on CrCL(d) was found, regardless of CrCL integrity, forced stifle joint subluxation, or flexion angle.

CONCLUSIONS AND CLINICAL RELEVANCE

Overt cranial tibial subluxation in CrCL-deficient stifle joints can be detected on mediolateral projection radiographs by comparing CrCL(d) on neutral and stressed joint radiographs at joint angles between 105° and 150°, regardless of whether a TPLO has been performed.

The effects of extra-articular suture tension on contact mechanics of the lateral compartment of cadaveric stifles treated with the TightRope CCL or lateral suture technique

OBJECTIVE

To determine the effect of suture tension on contact pressures in the lateral compartment of the stifle for the TightRope CCL((R)) (TR) and circumfabellar-tibial suture (LS) techniques.

STUDY DESIGN

Ex vivo biomechanical study.

SAMPLE POPULATION

Pelvic limbs (n=12) from dogs weighing 21-24 kg.

METHODS

A pressure sensor was used to record peak contact pressure (PCP) and mean contact pressure (MCP) and contact area (CA) in limbs mounted in a materials testing machine. Stifles were stabilized using either a TR or LS technique and the prosthesis was tensioned increasingly from 25 to 70 N. PCP, MCP, and CA were collected at each applied tension before and after applying an axial load of 150 N.

RESULTS

In the unloaded condition, LS stabilization resulted in a significant increase (P=.034) in PCP at >or=40 N tensions, whereas TR stabilization resulted in a significant increase (P=.047) in PCP at 70 N tension. There was a significant increase in CA at tensions >or=60 N in the LS group. No effect on MCP was noted. No significant differences in contact pressures were observed in the loaded condition. There were no significant differences in normalized PCP and CA between stabilization groups at any of the tension increment.

CONCLUSIONS

The application of high tension to the extra-articular prosthesis alters lateral compartment contact pressures in the unloaded stifle in this ex vivo model.

CLINICAL RELEVANCE

Over tightening of an extra-articular prosthesis may increase lateral compartment pressure at the time of surgery. The clinical implications of this finding are unknown, as weight bearing may negate any detrimental effect of high prosthesis tension.

Surgical views: Vacuum-assisted wound closure: clinical applications

Vacuum-assisted closure (VAC) is a wound management system that exposes a wound bed to local negative pressure to promote healing. Benefits of VAC therapy include removal of fluid from the extravascular space, improved circulation, enhanced granulation tissue formation, and increased bacterial clearance. VAC therapy has been used extensively in human patients to treat a variety of acute and chronic wound conditions. This article reviews the use of VAC therapy in a variety of wound conditions and describes our experiences with using VAC therapy in dogs and cats at the University of Florida.

Descriptive report of antebrachial growth deformity correction in 17 dogs from 1999 to 2007, using hybrid linear-circular external fixator constructs

The radiographic and clinical results from 17 dogs (18 limbs) in which hybrid linear-circular external fixators (HLCEF) were used for the correction of antebrachial growth deformities (AGD) are described, retrospectively. Wedge ostectomy and the application of a type IA or IB HLCEF were performed in all cases. Pre- and postoperative AGD measurements, complications, time to staged destabilization and/or fixator removal, cosmesis, and limb function were evaluated. Complications included wire and/or pin tract inflammation (11 limbs) and radial fracture (2 limbs). All dogs had improved function and appearance after surgery. Limb function was assessed as excellent in 13 cases and good in 4 cases. Limb appearance was assessed as excellent in 12 cases and good in 5 cases. This case series substantiates the utility of HLCEF for the correction of AGD in dogs.

Effect of tibial plateau leveling osteotomy on femorotibial contact mechanics and stifle kinematics

OBJECTIVE

To evaluate the effects of tibial plateau leveling osteotomy (TPLO) on femorotibial contact mechanics and 3-dimensional (3D) kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs.

STUDY DESIGN

In vitro biomechanical study.

ANIMALS

Unpaired pelvic limbs from 8 dogs, weighing 28-35 kg.

METHODS

Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135 degrees. Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TPLO-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test (P<.05) was used for statistical comparison.

RESULTS

Significant disturbances to all measured contact mechanical variables were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and increased internal tibial rotation in the CrCL-deficient stifle. No significant differences in 3D femorotibial alignment were observed between normal and TPLO-treated stifles; however, femorotibial contact area remained significantly smaller and peak contact pressures in both medial and lateral stifle compartments were positioned more caudally on the tibial plateau, when compared with normal.

CONCLUSION

Whereas TPLO eliminates craniocaudal stifle instability during simulated weight bearing, the procedure fails to concurrently restore femorotibial contact mechanics to normal.

CLINICAL RELEVANCE

Progression of stifle osteoarthritis in dogs treated with TPLO may be partly the result of abnormal stifle contact mechanics induced by altering the orientation of the proximal tibial articulating surface.

Management of Humeral and Femoral Fractures in Dogs and Cats With Linear- Circular Hybrid External Skeletal Fixators

Linear-circular hybrid fixators were used to stabilize humeral and femoral fractures in 21 dogs and five cats. Twenty-two of 24 fractures with sufficient follow-up radiographic evaluation obtained union. Time to radiographic union ranged from 25 to 280 days (mean ± standard deviation [SD] 110±69 days; median 98 days). Eleven animals developed minor and two dogs developed major pin and/or wire tract inflammation. Functional outcome was rated as excellent (n=16), good (n=5), and fair (n=3) at the time of final long-term assessment (range 4.5 to 60.0 months; mean ± SD 28.4±15.4 months; median 28.5 months). Follow-up information was unavailable for two animals. Hybrid fixators were useful constructs for stabilization of humeral and femoral fractures, particularly fractures with short, juxta-articular fracture segments.

Dicondylar humeral fracture stabilisation in a dog using a transilial rod and external fixation

Repair of a Salter-Harris type IV dicondylar humeral fracture was performed on a 15-week-old pitbull terrier. Interfragmentary compression of the intracondylar component of the fracture was achieved with a transilial rod and locking nuts (Trans-ilial Rod; IMEX Veterinary, Inc.). The transilial rod was articulated with a modified type I external fixator which functioned as adjunctive stabilisation for the supracondylar component of the fracture. Fracture healing was confirmed radiographically five weeks following surgery. The dog had no appreciable lameness when examined 12 months after fracture repair.

Tibial osteotomies for cranial cruciate ligament insufficiency in dogs

OBJECTIVE

To review the biomechanical considerations, experimental investigations, and clinical data pertaining to tibial osteotomy procedures for treatment of cranial cruciate ligament (CrCL) insufficiency in dogs.

STUDY DESIGN

Literature review.

METHODS

Literature search through Pub Med, Veterinary Information Network, Commonwealth Agricultural Bureau Abstracts, and conference proceedings abstracts (November 1977 to March 2007).

RESULTS

Reported tibial osteotomy procedures attempt to eliminate sagittal instability (cranial tibial thrust) in CrCL-deficient stifles by altering the conformation of the proximal tibia. Functional stability can be achieved by decreasing the tibial plateau slope (cranial tibial closing wedge osteotomy [CTWO], tibial plateau leveling osteotomy [TPLO], combined TPLO and CTWO, proximal intraarticular osteotomy, chevron wedge osteotomy), altering the alignment of the patellar tendon (tibial tuberosity advancement), or both (triple tibial osteotomy). Clinical reports assessing the efficacy of these procedures frequently use subjective outcome measures, and the periods of follow-up evaluation are highly variable. Satisfactory results have been reported in most (>75%) dogs irrespective of the type of tibial osteotomy procedure.

CONCLUSIONS

Currently available data does not allow accurate comparisons between different tibial osteotomy procedures, or with traditional methods of stabilizing the CrCL-deficient stifle. Carefully designed long-term clinical studies and further biomechanical analyses are required to determine the optimal osteotomy technique, and whether these procedures are superior to other stabilization methods.

CLINICAL RELEVANCE

Limb function in dogs with CrCL insufficiency can be improved using the currently described tibial osteotomy techniques.

Limited open reduction and stabilization of sacroiliac fracture-luxations using fluoroscopically assisted placement of a trans-iliosacral rod in five dogs

OBJECTIVE

To describe percutaneous fluoroscopically assisted placement of a trans-iliosacral rod to stabilize sacroiliac fracture-luxations after limited open reduction.

STUDY DESIGN

Retrospective clinical case series.

ANIMALS

Dogs (n=5) with sacroiliac fracture-luxations.

METHODS

Medical records and radiographs were reviewed to evaluate implant placement, fracture reduction, pelvic canal diameter ratio, maintenance of reduction, implant stability, assessment of union, and to identify any complications. Owners were contacted to obtain long-term assessment of limb function.

RESULTS

Dogs weighed between 6 and 31 kg. Trans-iliosacral rods were placed correctly traversing the sacral body. Mean (+/-SD) percent reduction of the sacroiliac joint was 92.9+/-6.6%. Pelvic canal diameter ratio did not differ significantly between time periods. With the exception of 1 dog, which died in the early postoperative period, all sacroiliac fracture-luxations healed without appreciable complications. Three dogs were sound and 1 dog had a subtle lameness at final physical and radiographic examination (mean+/-SD: 217+/-205 days). Owners assessed their dog's limb function (mean+/-SD: 355+/-205 days) as good or excellent.

CONCLUSIONS

Trans-iliosacral rods can be accurately placed using intraoperative fluoroscopy after limited open reduction of sacroiliac fracture-luxations. Trans-iliosacral rods provided bilateral secure fixation, allowed early weight-bearing and dogs consistently had good long-term clinical results.

CLINICAL RELEVANCE

Trans-iliosacral rods are suitable implants for the stabilization of sacroiliac fracture-luxations, particularly in dogs with bilateral fracture-luxations and/or concurrent musculoskeletal injuries.

Bilateral correction of metatarsal rotation in a dog using circular external skeletal fixation

An 8-month-old castrated male Saint Bernard was evaluated for bilateral hind limb lameness. Lameness was ascribed to bilateral metatarsal rotational abnormalities on the basis of the physical examination and radiographic evaluations. Staged, bilateral deformity correction and tarsometatarsal arthrodeses were performed using circular external skeletal fixators. The dog's gait improved following surgery and the fixators were removed 3 (left hind paw) and 4 (right hind paw) months following surgery. Twenty months after the initial surgery, the owner reported that the dog was walking well without apparent lameness. Previous reports suggest that metatarsal rotation is untreatable; however, our results suggest that surgical correction of this deformity can substantially improve limb function in dogs affected with metatarsal rotation.

Transverse ulnar bone transport osteogenesis: a new technique for limb salvage for the treatment of distal radial osteosarcoma in dogs

OBJECTIVE

To develop instrumentation and a technique for transverse ulnar bone transport osteogenesis in dogs.

STUDY DESIGN

Cadaveric study and in vivo validation (1 dog).

SAMPLE POPULATION

Paired cadaveric antebrachii (n=10 dogs) and 1 live dog.

METHODS

Circular fixator constructs were applied and fitted with reeling or linear motors designed to transport an ulnar segment transversely into a defect created by excising the distal 50% of the ipsilateral radius. A longitudinal osteotomy of the adjacent ulna was created and the segment was transported across the radial defect. Pre- and post-distraction CT scans were used to compare the efficacy of each construct. The procedure was performed unilaterally in a live dog using the reeling motor (RM) construct.

RESULTS

Both constructs effectively transported the ulnar segment into the defect. Subjectively, the RMs were easier to apply and operate. No significant differences were observed in the objective measures of efficacy between the 2 construct types. The live dog produced viable regenerate bone after transverse ulnar bone transport.

CONCLUSIONS

Transverse ulnar bone transport should be considered a potential method for limb salvage in dogs with osteosarcoma (OSA) of the distal radius. The RMs were effective and clinically applicable.

CLINICAL RELEVANCE

Transverse ulnar bone transport osteogenesis affords the benefits of longitudinal radial bone transport osteogenesis, allowing resolution of large longitudinal radial defects in a substantially less time as a result of shortening the transport distance. This would be beneficial when treating conditions such as OSA where minimizing convalescence and maximizing quality of life is a priority.

Closed Fluoroscopic-Assisted Spinal Arch External Skeletal Fixation for the Stabilization of Vertebral Column Injuries in Five Dogs

OBJECTIVE

To evaluate outcome after closed fluoroscopic-assisted application of spinal arch external skeletal fixators in dogs with vertebral column injuries.

STUDY DESIGN

Retrospective case series.

ANIMALS

Dogs with traumatic vertebral column injuries (n=5).

METHODS

Medical records of dogs with vertebral column fractures and/or luxations stabilized with spinal arch external skeletal fixator frames applied using a closed fluoroscopic-assisted technique were reviewed. Owners were contacted to obtain long-term clinical outcomes.

RESULTS

Five dogs (age range, 6-72 months; weight, 10-54 kg) had traumatic vertebral column injuries stabilized with spinal arch external skeletal fixators applied in closed fashion. Injuries involved vertebral segments of the thoracolumbar junction, lumbar spine, and lumbosacral junction. Immediately postoperatively, 4 dogs had anatomic alignment of their vertebral fracture/luxation; 1 dog had 1 mm of vertebral canal height compromise. Time to fixator removal ranged from 65 to 282 days (141+/-87 days). All dogs had regained satisfactory neurologic function by 3 months. At long-term follow-up (range, 282-780 days; mean 445+/-190 days) all dogs were judged to have good to excellent return of function by their owners.

CONCLUSION

Successful closed fluoroscopic-assisted application of external skeletal fixators using spinal arches provided satisfactory reduction with few complications in 5 dogs. Return to function was judged to be good to excellent in all dogs at long-term evaluation.

CLINICAL RELEVANCE

Closed fluoroscopic-assisted application of ESF using spinal arches provided satisfactory reduction and effective stabilization of spinal fractures with few complications and should be considered as a treatment approach.

Short-Term Aseptic Loosening of the Femoral Component in Canine Total Hip Replacement: Effects of Cementing Technique on Cement Mantle Grade

OBJECTIVES

To evaluate the effects of different cementing techniques on radiographic cement mantle grade and short-term aseptic loosening of the femoral component in canine total hip replacement (THR).

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Radiographs of 284 dogs that had THR.

METHODS

Immediate postoperative radiographs of 284 dogs that had cemented THR were reviewed by 4 surgeons and 1 radiologist and assigned a cement mantle grade using a 4-grade classification system. Dog age and weight at surgery, cementing technique (1st, 2nd, 3rd generation), complications (type and timing), and follow-up time were retrieved and analyzed.

RESULTS

Mean cement mantle score for 2nd generation technique was significantly higher than 3rd generation technique and both were significantly higher than 1st generation technique (P<.001). Aseptic loosening was the 2nd most common complication observed with an incidence of 2.1%. Mean time from surgery to last follow-up examination was 122 days. No statistically significant difference in incidence of aseptic loosening was identified among different cement mantle grades or cementing techniques.

CONCLUSIONS

Advanced cementing techniques resulted in better cement mantles based on grading of immediate postoperative radiographs, however grading did not predict short-term aseptic loosening. Cementing technique seemingly did not affect the incidence of short-term aseptic loosening of the femoral component for dogs in this study.

CLINICAL RELEVANCE

Our study suggests that advances in cementing technique may result in improvements in the radiographic grade of cement mantles. With respect to aseptic loosening of the femoral component, our data only suggest that short-term (3 months-3 years) loosening cannot be predicted by immediate postoperative radiographic evaluation of cement mantle.

Effect of mild restriction of food intake on the speed of racing Greyhounds

OBJECTIVE

To determine whether mild restriction of food intake affects clinicopathologic variables, body composition, and performance of dogs undertaking intense sprint exercise.

ANIMALS

9 trained healthy adult Greyhounds.

PROCEDURE

Dogs were offered food free choice once daily for 9 weeks until body weight and food intake stabilized. Dogs were then randomly assigned to be fed either 85% or 100% of this quantity of food in a crossover study (duration of each diet treatment period, 9 weeks). Dogs raced a distance of 500 m twice weekly. Clinicopathologic variables were assessed before and 5 minutes after racing; food intake, weight, body composition, body condition score, and race times were compared at the end of each diet period.

RESULTS

Compared with values associated with unrestricted access to food, there were significant decreases in mean body weight (by 6%) and median body condition score (from 3.75 to 3.5 on a 9-point scale) and the mean speed of the dogs was significantly faster (by 0.7 km/h) when food intake was restricted. Body composition and most clinicopathologic variables were unaffected by diet treatment, but dogs given restricted access to food had slightly fewer neutrophils, compared with values determined when food intake was unrestricted.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that the common practice among Greyhound trainers of mildly restricting food intake of racing dogs to reduce body weight does improve sprint performance. A body condition score of approximately 3.5 on a 9-point scale is normal for a trained Greyhound in racing condition.

Treating pedal shortening in a dog by metatarsal distraction osteogenesis

A five-month-old, male German shepherd dog was presented with a left hindlimb deformity. Wearing a cast for a prolonged period to treat left metatarsal fractures at eight weeks of age had resulted in physeal closure of the calcaneus, metatarsals and phalanges. Hyperextension of the phalanges and ulceration of the plantar skin proximal to the main tarsal pad were seen. The left foot was 40 mm shorter than the right. At seven months of age, a modified circular external skeletal fixator (CESF) was used to perform distraction osteogenesis of the metatarsal bones for 28 days. The CESF apparatus was removed after eight weeks when there was radiographic consolidation of regenerate bone. At follow-up evaluations four and 12 months after surgery, the phalangeal hyperextension and plantar skin ulceration had resolved. No lameness was detected.