Use of Recombinant Human Bone Morphogenetic Protein for Fracture Healing in Dogs
Milovancev M, Muir P, Manley P, et al. Clinical application of recombinant human morphogenetic protein-2 in 4 dogs. Vet Surg 2007;36:132-140.
Abstract: In this series of cases at a veterinary school in the US Midwest, four dogs with bone nonunion or delayed bone healing were treated with recombinant human bone morphogenetic protein-2 (rhBMP-2). The dogs had previously undergone femoral fracture pinning and subsequent revision by plating, corrective radial osteotomy with external ring fixation, pantarsal arthrodesis with plating, and humeral fracture pinning/external fixation. Following clinical and radiographic examinations that confirmed a lack of adequate bone healing, rhBMP-2 in a calcium phosphate matrix was applied in a minimally invasive manner to the fracture site in three dogs. A commercial product impregnated in an absorbable collagen sponge was used in one dog. Transient lameness was described in two dogs following percutaneous placement of rhBMP-2. In all the dogs, rapid radiographic evidence of bone union was noted by 1 to 2 months, and long-term evaluations revealed excellent limb function. The authors concluded that rhBMP-2 applied percutaneously or directly in surgery stimulated bone healing in these various orthopedic conditions, including inadequate bone healing complicated by infection.
Commentary: In orthopedic surgery, bone nonunions and delayed bone unions, along with osteomyelitis, are serious complications, involving not only patient morbidity but also financial issues for clients. The causes invariably relate to poor surgical technique and subsequent implant failure or traumatically induced poor tissue viability. Treatments include fracture restabilization procedures and bone grafting. Autogenous bone grafting is considered the "gold standard" based on biologic and mechanical characteristics in stimulating fracture healing. In this report, the authors describe a commercial human morphogenetic glycoprotein that was simply applied to, and apparently quickly healed, bone nonunions and delayed bone unions in dogs. The interspecies homology for rhBMP-2 is 100% in mammals, which permits its use in small animals. The authors acknowledge, however, the low number of patients in this clinical study and variable nature of the doses used. Furthermore, many practitioners would question the availability and cost of the product. More clinical trials are needed to determine whether this compound is useful in treating the plethora of veterinary orthopedic injuries and whether it should replace or augment the current use of allografts and autografts.
Canine Juvenile Weight Gain Associated with Coxofemoral Joint Laxity
Lopez MJ, Quinn MM, Markel MD. Associations between canine juvenile weight gain and coxofemoral joint laxity at 16 weeks of age. Vet Surg 2006;35:214-218.
Relationships between juvenile weight gain and coxofemoral joint (CFJ) laxity in dogs with canine hip dysplasia (CHD) suggest that early weight gain may affect passive CFJ laxity. This study (which included 56 mixed-breed hounds after weaning, six dams, and one sire, all with CFJ disease) hypothesized greater CFJ laxity in puppies with the highest weight gain rates from 6 to 15 weeks of age. Passive CFJ laxity was quantified via the PennHIP distraction index (DI); dogs ate PMI Nutrition Prime Formula ad libitum. Weekly weights and average daily gain (ADG; actual or normalized; weekly and total) were measured. Analyses involved descriptive statistics, mixed-effects linear models, and Student's paired t-test comparing DIs.
A mean DI of 0.67 indicated that most puppies were prone to CFJ changes consistent with CHD. The highest or mean DI was not significantly correlated with ADGs; within-animal right and left DIs were not significantly different. One model revealed a trend for a negative relationship between normalized 14-week ADG and DI.
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