Enhancement of bone healing using non-glycosylated rhBMP-2 released from a fibrin matrix in dogs and cats

OBJECTIVES: To test a non-glycosylated recombinant human bone morphogenetic protein-2 (ngly-rhBMP-2)/fibrin composite, which has been shown experimentally to enhance healing of bone defects in rodents, in a clinical case series of dogs and cats undergoing treatment for fracture non-unions and arthrodesis. METHODS: A ngly-rhBMP-2/fibrin composite was applied in 41 sites in 38 dogs and cats for which a cancellous bone autograft was indicated, replacing the graft. RESULTS: Bridging of the bone defect with functional bone healing was achieved in 90 per cent of the arthrodesis and fracture nonunions treated in this manner. CLINICAL SIGNIFICANCE: This prospective clinical study demonstrates the beneficial effects of ngly-rhBMP-2 in a specially designed fibrin matrix on the treatment of bone defects, and validates the use of this composite as an alternative to bone autografts in dogs and cats.     

Treatment of severely comminuted diaphyseal fractures in the dog, using standard bone plates and autogenous cancellous bone graft to span fracture gaps: 11 cases (1979-1983)

Severely comminuted diaphyseal fractures in 11 dogs were repaired with standard bone plates that spanned a fracture gap filled with autogenous cancellous bone graft. Five dogs had closed injuries, 4 dogs had open fractures, and 2 dogs had infected nonunion fractures for which previous attempts at internal pin fixation had failed. A second autogenous cancellous bone graft was performed in 3 of the dogs during the healing period. The technique was successful in all dogs. The technique was considered a versatile and relatively simple alternative, compared with meticulous small fragment reconstruction and cortical bone allografts.     

Evaluation of serum biochemical markers of bone metabolism for early diagnosis of nonunion and infected nonunion fractures in rabbits

OBJECTIVE: To evaluate the use of serum concentrations of biochemical markers of bone metabolism (osteocalcin [OC], bone-specific alkaline phosphatase [BS-ALP], and deoxypyridinoline [DPYR]) to compare healing in infected versus noninfected fractures and in fractures with normal repair versus delayed (nonunion) repair in rabbits. ANIMALS: 32 female 9- to 10-month-old New Zealand White rabbits. PROCEDURE: A femoral fracture defect was made in each rabbit. Rabbits were assigned to the following groups: the bone morphogenetic-2 gene treatment group with either noninfected nonunion or infected (ie, inoculation of defects with Staphylococcus aureus) nonunion fractures or the luciferase (control) gene treatment group with either noninfected nonunion or infected nonunion fractures. Serum samples were obtained before surgery (time 0) and 4, 8, 12, and 16 weeks after surgery. Callus formation and lysis grades were evaluated radiographically at 16 weeks. RESULTS: Serum OC and BS-ALP concentrations decreased from time 0 at 4 weeks, peaked at 8 weeks, and then decreased. Serum DPYR concentration peaked at 4 weeks and then decreased, independent of gene treatment group or fracture infection status. Compared with rabbits with noninfected fractures, those with infected fractures had lower serum OC and BS-ALP concentrations at 4 weeks, higher serum OC concentrations at 16 weeks, and higher serum DPYR concentrations at 4, 8, and 16 weeks. Combined serum OC, BS-ALP, and DPYR concentrations provided an accuracy of 96% for prediction of fracture infection status at 4 weeks. CONCLUSIONS AND CLINICAL RELEVANCE: Measurement of multiple serum biochemical markers of bone metabolism could be useful for clinical evaluation of fracture healing and early diagnosis of osteomyelitis.     

Repair of diaphyseal femoral fractures in cats using interlocking intramedullary nails: 12 cases (1996-2000).

OBJECTIVE: To determine the outcome of femoral fractures repaired with 4.0- and 4.7-mm interlocking intramedullary nails in cats. DESIGN: Retrospective study. ANIMALS: 12 cats with diaphyseal femoral fractures. PROCEDURE: Records of all cats in which the 4.0- and 4.7-mm interlocking nail system was used for repair of diaphyseal femoral fractures at the Animal Medical Center and Florida Veterinary Specialists between 1996 and 2000 were reviewed. Information included signalment, type of fracture, size of the implant, details of the surgery, intra- and postoperative complications, fracture healing, and clinical outcome. RESULTS: Femoral fractures in 12 cats were repaired. Eleven of the fractures were comminuted, with 2 of these being open. Clinical outcome was excellent in 7 cats, good in 3, and fair in 1. One resulted in a nonunion. Complications included screw breakage (1 cat) and fracture distal to the nail (1). Fracture distal to the nail occurred from a second trauma. CONCLUSION AND CLINICAL RELEVANCE: Use of the interlocking nail has been limited in cats because of the small diameter of the medullary canal. Use of the 4.0-mm nail will allow for greater application of this implant in small patients. Results of this study indicate that the 4.0- and 4.7-mm interlocking nails can be used to repair simple or comminuted diaphyseal femoral fractures in cats.     

Evaluation of Key's hypothesis in the feline tibia: an experimental model for augmented bone healing studies

Key's hypothesis states that a segmental long bone defect 1.5 times the diaphyseal diameter exceeds the regenerative capacity of bone in skeletally mature dogs and results in nonunion. This hypothesis was evaluated in 5 adult cats with rigidly fixated segmental tibial ostectomies ranging from 1.25 to 1.52 times the diaphyseal diameter. Clinical, radiographic, and histologic data were obtained over a 12-week period. Healing was classified as mature bony union, clinical union, delayed union, or nonunion. Absence of a consolidating callus and instability after removal of fixation devices was found for all cats at 12 weeks. Scant formation of new bone within the gap was histologically evident for only 1 cat. In the remaining 4 cats, fibrous tissue and striated muscle predominated within the gap, and independent healing of the proximal and distal cut ends of the bone were observed. The occurrence of 4 nonunions and 1 equivocally delayed union indicated that Key's hypothesis overestimates the regenerative capacity of bone in the cat. Failure of this experimental model to produce clinical union within 12 weeks demonstrated that this model is a valid method of investigating augmented bone healing techniques that promote union within this period in the cat.     

Correlation of serum alkaline phosphatase activity with the healing process of long bone fractures in dogs

BACKGROUND: Bone healing is monitored mainly by physical and serial radiologic examinations of the fracture site. However, it is sometimes difficult to distinguish a delayed union from a nonunion, and advanced imaging techniques may not be available. Serum biochemical markers of bone formation, such as alkaline phosphatase (ALP) activity, may be clinically useful in evaluating the progress of healing. OBJECTIVE: The purpose of this study was to correlate serial values of serum ALP activity with the process of fracture healing in dogs and to assess its potential as a postsurgical prognostic indicator. METHODS: Changes in serum ALP activity were studied in 83 dogs with closed long bone diaphyseal fractures treated surgically. Physical and radiologic examinations of the fracture site and determination of serum ALP activity and calcium (Ca) and phosphate (P) concentrations were performed on admission (day 0); postoperatively on days 10, 20, and 30; and subsequently on a monthly basis until bone union was completed or signs of nonunion were evident. The dogs were allocated into 3 groups with respect to the fracture healing progress as documented by physical and serial radiologic examination. RESULTS: Group A dogs (n=35) developed a medium-sized callus that led to bone union within 2 months. Group B dogs (n=36) had a hypertrophic callus and delayed union, within 3-5 months. Group C dogs (n=12) had slow progress in fracture healing, with minimal callus formation during a 2-month period. Changes in mean serum ALP activity followed the same pattern in groups A and B, reaching a maximum level on day 10. Group A values returned to normal within 2 months, at which point bone union was complete, whereas group B values remained increased and returned to normal within 3-5 months, thus correlating with delayed union. In Group C, mean serum ALP activities showed no significant changes during the 2-month follow-up period, consistent with failure of bone union (nonunion). Serum P and Ca changes followed a proportional and inverse pattern to ALP changes, respectively. CONCLUSION: Serial determination of serum ALP activity during fracture healing could be an additional tool in predicting fractures at risk of developing a nonunion, helping the clinician to choose the appropriate intervention.     

Treatment of tibial fractures with plates using minimally invasive percutaneous osteosynthesis in dogs and cats

OBJECTIVES: The aim of the here described case series was to develop and evaluate the minimally invasive percutaneous osteosynthesis for the plate fixation of tibial fractures in dogs and cats. METHODS: Six dogs and four cats with shaft fractures of the tibia were treated using minimally invasive percutaneous osteosynthesis. Follow-up radiographs four to six weeks after fracture fixation were evaluated for fracture healing. For the long-term follow-up (minimum 2.4 years), owners were contacted by phone to complete a questionnaire. RESULTS: All fractures healed without the need for a second procedure. Follow-up radiographs obtained after four to six weeks in seven cases showed advanced bony healing with callus formation and filling of the fracture gaps with calcified tissue in all seven. All the patients had a good to excellent long-term result with full limb function. The time needed for regaining full limb use was two to three months. CLINICAL SIGNIFICANCE: Minimally invasive percutaneous osteosynthesis seems to be a useful technique for the treatment of tibial shaft fractures in dogs and cats.     

Radial and Tibial Fracture Repair with External Skeletal Fixation: Effects of Fracture Type, Reduction, and Complications on Healing

Twenty-eight consecutive fractures of the canine radius and tibia were treated with external skeletal fixation as the primary method of stabilization. The time of fixation removal (T1) and the time to unsupported weight-bearing (T2) were correlated with: (1) bone involved; (2) communication of the fracture with the external environment; (3) severity of the fracture; (4) proximity of the fracture to the nutrient artery; (5) method of reduction; (6) diaphyseal displacement after reduction; and (7) gap between cortical fragments after reduction. The Kruskal-Wallis one-way analysis of variance was used to test the correlation with p less than .05 set as the criterion for significance. The median T1 was 10 weeks and the median T2 was 11 weeks. None of the variables correlated significantly with either of the healing times; however, there was a strong trend toward longer healing times associated with open fractures and shorter healing times associated with closed reduction. Periosteal and endosteal callus uniting the fragments were observed radiographically in comminuted fractures, with primary bone union observed in six fractures in which anatomic reduction was achieved. Complications observed in the treatment of these fractures included: bone lysis around pins (27 fractures), pin track drainage (27 fractures), pin track hemorrhage (1 fracture), periosteal reaction around pins (27 fractures), radiographic signs consistent with osteomyelitis (12 fractures), degenerative joint disease (2 dogs), and nonunion (1 fracture). Valgus or rotational malalignment resulted in 16 malunions of fractures. One external fixation device was replaced and four loose pins were removed before the fractures healed. One dog was treated with antibiotics during the postoperative period because clinical signs of osteomyelitis appeared.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrasonographic and radiographic assessment of uncomplicated secondary fracture healing of long bones in dogs and cats

OBJECTIVES: To evaluate the use of ultrasonography (US) to detect bone healing in uncomplicated diaphyseal fractures of dogs and cats, and to compare these observations with detection of healing by radiography (RG). STUDY DESIGN: Clinical study. ANIMALS: Dogs (33) and cats (11). METHODS: RG and brightness mode US were used to follow uncomplicated secondary fracture healing. Fractures were examined at admission and then every 2-4 weeks until healed or implant removal. Temporal differences in definitive detection of healed fracture by imaging technique were examined by species, patient age, bone, and fracture type. RESULTS: US images obtained during uncomplicated secondary fracture healing were consistent with images of fracture healing described in humans. Mean time to US diagnosis of a healed fracture (mean 46 days) was significantly shorter than by RG (mean 66 days). Mean time until diagnosis of a healed fracture (US and RG) did not differ significantly between open and closed treatment. Patients 36 months (n=11), but there was no significant difference between the latter 2 groups. Diagnosis of a healed simple fracture by US was significantly quicker than for a comminuted fracture (P<.05), but no difference was noted when using RG. CONCLUSIONS: US can be used to evaluate secondary fracture healing in biologically treated fractures in dogs and cats. US permits detection of a healed fracture earlier than RG. CLINICAL RELEVANCE: Earlier diagnosis of a healed fracture by US can prevent unnecessarily long limb immobilization and allow earlier dynamization.     

Use of flexible intramedullary rods for fixation of femoral fractures in eight dogs

High-density, polysulfone rods were used to repair 4 comminuted and 4 short-oblique, mid-diaphyseal femoral fractures in 8 dogs. Bony union was achieved in 2 dogs at 10 and 12 weeks after surgery. In one dog, the femoral fracture was healing when amputation of the limb became necessary because of sciatic nerve damage secondary to an ipsilateral pelvic fracture. In a fourth dog, fracture repair resulted in nonunion, despite normal clinical function at 18 months after surgery. In the remaining 4 dogs (50%), the rods failed at 3.5, 4, 6, and 22 weeks after surgery. These fractures were then stabilized by use of other methods. Although several factors may have contributed to failure of the rods, multiple autoclaving of the thermoplastic implants may have caused embrittlement and subsequent breakage.     

Clinical application of recombinant human bone morphogenetic protein-2 in 4 dogs

OBJECTIVE: To describe outcome in dogs with insufficient bone healing treated with recombinant human bone morphogenetic protein-2 (rhBMP-2). STUDY DESIGN: Retrospective study. ANIMALS: Four dogs clinically affected with delayed union or nonunion bone healing. METHODS: Medical records were reviewed for signalment, clinical problem, treatment, and outcome. RESULTS: Four dogs that had delayed- or nonunion of bone fracture, osteotomy, or arthrodesis were treated with either minimally invasive, fluoroscopically guided, percutaneous administration or direct surgical application of rhBMP-2. Doses used ranged from 0.2 to 1.6 mg of rhBMP-2. In 3 dogs, a calcium phosphate matrix (CPM) carrier was used whereas in 1 dog commercially prepared rhBMP-2 impregnated in an absorbable collagen sponge (INFUSE Bone Graft) was used. This latter dog had osteomyelitis associated with implant infection before rhBMP-2 administration. Rapid radiographic union was noted in all dogs with excellent long-term outcome. Adverse effects were minimal and included transient worsening of lameness after percutaneous administration of rhBMP-2 in 2 dogs. CONCLUSIONS: rhBMP-2 stimulated rapid bone formation at delayed- or nonunion sites resulting in radiographic bone union with minimal adverse effects and excellent long-term outcome in 4 dogs. CLINICAL RELEVANCE: Direct intraoperative administration or fluoroscopically guided, minimally invasive delivery of rhBMP-2 may be an effective treatment modality for bone delayed- or nonunions and could potentially be used to stimulate new bone production in a variety of orthopedic surgical conditions in dogs.     

Comminuted long bone fractures in cats caused by pneumatic gun shot and repaired using the external fixator "tie-in" technique

Five cats with femoral fractures caused by pneumatic gun shot wounds were treated using intramedullary pin/external skeletal fixation "tie-in" (IM/ESF tie-in) technique between 1997 and 2005. Clinical and radiographical examinations were used to assess bone healing, limb function recovery and complications. Clinical results as well as fracture healing were excellent in all five cats. The study showed that the IM/ESF tie-in technique can be used in cats for the treatment of comminuted femoral fractures caused by pneumatic bullets.     

Incidence of and predisposing factors for nonunion of fractures involving the appendicular skeleton in cats: 18 cases (1998-2002)

OBJECTIVE: To identify the most common sites of and possible predisposing factors for nonunions in cats with fractures of the appendicular skeleton. DESIGN: Retrospective study. ANIMALS: 344 cats treated for fractures between 1998 and 2002, 18 of which developed nonunions. PROCEDURES: Information collected from the medical records included signalment; type of trauma; fracture location, orientation, and type; degrees of displacement and comminution; treatment; and outcome. RESULTS: The tibia and proximal portion of the ulna were identified as the most common sites for nonunions. Factors significantly associated with development of a nonunion included age, body weight, affected bone, fracture type, degree of comminution, and fixation type, with older cats, heavier cats, cats with fractures of the tibia or proximal portion of the ulna, cats with open fractures, cats with comminuted fractures, and cats with fractures stabilized with a type II external skeletal fixator being significantly more likely to develop a nonunion. Eleven of the 18 cats with nonunions had a successful outcome following treatment of the nonunion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in cats, fractures involving the tibia and proximal portion of the ulna are more likely to develop nonunions than are fractures involving other sites but that many factors may increase the risk of nonunion. Use of excessively large and rigid type II external skeletal fixators may be associated with development of nonunions; however, type II external skeletal fixators were commonly used to stabilize fractures in sites predisposed to nonunion.     

Early Experience With the Use of an Interlocking Nail for the Repair of Canine Femoral Shaft Fractures

Static locked nailing was used to repair fractures of the femoral diaphysis in 15 dogs. The implant consists of a 5, 6, or 7 mm diameter stainless steel rod made up of two parts: the body of the nail, in which there are 13 threaded holes, and a piece without holes that contains a slot for anchoring the jig. Good limb function was obtained after less than 3 weeks in 12 dogs and these dogs remained sound throughout the study. Radiographic examination revealed fracture healing in 11 of the dogs, between 8 and 16 weeks after surgery. One dog was not returned for follow-up evaluation until 22 weeks after surgery; complete healing was apparent from radiographic examination. The remaining three dogs had to have additional operations, one because of lameness caused by excessive length of the distal screws, one because of a nonunion, and the third because of a sequestrum. Fracture healing in these dogs was observed at 18, 21, and 24 weeks respectively. Loosening of one screw and angulation of the bone occurred in one dog. These complications had no adverse effects on clinical outcome.     

Radiologic and gross anatomic evaluation of bone healing in the dog.

Bone healing associated with 3 techniques of midshaft femoral fracture fixation in 36 young adult Beagle-type dogs was evaluated in radiographic and gross pathoanatomic studies. A serrated transverse fracture was surgically and aseptically created on the midshaft of either the left or the right femur of each dog. The fixation devices used were intramedullary (IM) pin, IM pin and 1/2 Kirschner device, and tension bone plates. The radiographic evaluation was done in series. The first radiographs were taken during surgery. Radiographs were then taken immediately after surgery, to record the status of reduction, alignment, and fixation. Radiographs were taken at the 4th and 10th postoperative weeks, to monitor healing. All dogs were euthanatized at the 10th week. Both the normal femur and the healing femur were removed from all dogs, all soft tissue was removed from the bone, and each femur was examined grossly. Each type of fixation was associated with a distinct mode of osteogenesis. Bony union and clinical union (that stage in the healing process when fixation can be removed) were defined as a successful conclusion to each case. Malunion and nonunion were defined as unsuccessful conclusions. Delayed union was defined as neither successful nor unsuccessful. The IM pin cases had a 64.2% success rate and a 14.2% failure rate. The IM pin and 1/2 Kirschner cases had a 100% success rate. The bone plate cases were 91% successful, with 0% failure. A problem identified with IM pinning was axial rotation (6 of 14 or 42% of the cases). It was concluded that IM pins should not be used alone for the fixation of femoral fractures in adult dogs.     

Comparison of bone healing by demineralized bone matrix and autogenous cancellous bone in horses

OBJECTIVE: The purpose of this study was to compare bone healing induced by equine demineralized bone matrix (DBM) to autogenous cancellous bone graft (ACB) or no graft (control) in a rib-defect model in horses. STUDY DESIGN: The osteogenic properties of ACB and DBM were evaluated in bilateral 19-mm circular defects created in the outer cortex of the 6th and 8th ribs of each horse. ANIMALS OR SAMPLE POPULATION: Eight mature horses. METHODS: Three rib defects in each horse were randomly treated with each of the 3 treatment groups, and the fourth rib defect received a random treatment. Rib sections, including the defects, were harvested 56 days after implantation and examined for bone mineral density, percent ash and calcium and graded for signs of radiographic and histological healing. RESULTS: All ribs were fractured at the defect site and were classified as nonunion fractures 56 days after implantation. There were no significant differences among groups in bone mineral density and signs of radiographic or histological healing. There was an increased volume of bone in control and ACB-treated sites compared with DBM-treated sites. Rib defects treated with ACB were significantly higher in percent ash and calcium than those treated with DBM. DBM elicited no inflammatory reaction, and remodeling occurred around the periphery and within vascular channels of the decalcified particles. CONCLUSION: DBM particles remodel from the periphery, which may explain the significantly lower percent ash, calcium, and bone when compared with ACB, because 2- to 4-microL pieces of DBM may act as space-occupying masses until completely mineralized. There was no evidence of enhanced healing associated with the use of DBM in this model. CLINICAL RELEVANCE: Particles of 2 to 4 mm DBM should not be used as an aid to fracture repair because particles of this size interfere with normal mineralization. However, our model of nonunion fracture healing may be useful in future studies.     

Use of intramedullary fully-threaded pins in the fixation of feline and canine humeral, femoral and tibial fractures

Intramedullary fully-threaded pins were manufactured from an alloy of titanium, aluminium and vanadium in a fully-threaded style. Pins were produced in various diameters, ranging from 4 mm to 11 mm. Pin lengths varied from 5 cm to 22 cm. The proximal end of the pins was designed to fit into a hexagonal screwdriver, while the distal end was slightly tapered to allow for ease of entry into cancellous bone. Treatment using the fully-threaded intra- medullary pin was carried out in a total of 175 fractures of the humerus, femur, and tibia in 95 cats (bilateral femur in 1 case) and 77 dogs (bilateral femur in 2 cases). Radiographic follow-up for the cases was performed at monthly intervals. Non-union developed in one dog with a femoral fracture in which cerclage wire had also been used. Delayed healing and lameness were observed in two other dogs. Healing with excessive callus formation was observed in 16 dogs. However, there were not any problems noted in these dogs in regards to limb usage. Clinical and radiological results obtained for the remaining cases were found to be very good. Normal, complete fracture healing occurred between four to 14 weeks in dogs, and between four to 12 weeks in cats. Pins were removed upon observation of satisfactory functional and radiographic recovery. Pins could not be removed from 26 cats and 21 dogs as the owners had declined pin removal, or because the owners were lost to follow-up.     

Treatment of biologically inactive nonunions by a limited en bloc ostectomy and compression plate fixation: a review of 17 cases

OBJECTIVE: To describe a surgical technique for treatment of biologically inactive nonunions using en bloc ostectomy and compression plate fixation and clinical outcome in 17 dogs. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Seventeen dogs. METHODS: A transverse ostectomy was performed adjacent and parallel to the nonunion to eliminate nonviable tissue and provide a new, viable fracture surface with a minimum circumferential contact area of 315 degrees. With most of the bony column anatomically reconstructed, compression plate fixation was used to stabilize the fracture. Autogenous cancellous bone grafting was used if a fracture gap was present (<45 degrees of missing circumferential bone contact). Resection of bone was limited so that bone shortening was less than 20% of the overall bone length. Clinical and radiographic follow-up evaluations were obtained whenever possible. RESULTS: Complete circumferential bone contact and compression plate fixation was achieved after ostectomy in 12 dogs; cancellous bone graft was used in 5 dogs. En bloc ostectomy sites were radiographically healed in a median time of 2.5 months after surgery in 11 dogs that returned for complete in-hospital follow-up, and progressive healing was observed in 3 other dogs, where in-hospital follow-up was obtained up to 2 months after surgery. These dogs had a median follow-up time of 2 months, at which time 6 dogs had no lameness, 4 had minimal lameness, and one had moderate lameness. No complications occurred, and no implants were removed. CONCLUSIONS: En bloc ostectomy with compression plate fixation was considered successful for the treatment of biologically inactive nonunions. A good to excellent prognosis can be expected with minimal complications. CLINICAL RELEVANCE: Use of an en bloc ostectomy technique for the treatment of biologically inactive nonunions permits easy resection of nonviable tissue. Subsequent fracture stabilization with compression plate fixation resulted in rapid bone healing without complications.     

Deep-Frozen Allogeneic Cancellous Bone Grafts in 10 Dogs: A Case Series

Deep-frozen, aseptically collected and processed allogeneic cancellous bone was implanted in eight dogs during the surgical repair of diaphyseal long bone fractures and in two dogs during arthrodeses. A combined allogeneic and autogeneic cancellous bone graft was used in two fractures with a segmental bone loss of more than 5 cm. Bone union occurred in five fractures and in both arthrodeses. Failure of fixation occurred in two dogs with nonunion fractures and in a third dog with an open, infected fracture. Biopsies from the fracture sites were obtained from these dogs following failure of their fracture fixation. The cancellous bone graft appeared to be in the process of normal incorporation in each case. Failure of fixation was attributed to technical or case management errors or both, in each of the three fractures that failed to achieve bony union. Frozen allogeneic cancellous bone grafts were effectively incorporated when used in the primary repair of fractures and arthrodeses. Combined autogenous and allogeneic cancellous bone grafts may be particularly useful in the repair of fractures with large segmental diaphyseal bone defects. The use of allogeneic cancellous bone grafts in nonunion fractures requires further investigation before it can be recommended.     

Distal tibial fractures in dogs and cats

A total of 43 fractures of the distal tibia in dogs and cats were evaluated for fracture patterns, methods of stabilization, and time to bone union. Fractures of the metaphysis (9.3%), physis (30.9%), epiphysis (2.3%), and malleoli (58.2%) were classified. Open reduction and internal fixation, with combinations of Kirschner wire, orthopedic wire, and bone screws, were the methods of fixation used in the majority of fractures. These relatively simple methods of fixation were applied to all sizes of dogs and cats and resulted in an average bone healing time of 6 weeks.