Surgical repair of Salter-Harris type II fracture of the distal humerus: short and long-term outcomes in a case series of three dogs and one cat.

CASE HISTORIES: Three dogs and one cat sustained forelimb trauma and were presented to a university veterinary clinic (Liège, Belgium) and a private veterinary hospital (Beacouzé, France). All four animals were referred for surgery. CLINICAL FINDINGS: Two dogs and the cat were ambulatory on admission but unable to bear weight on the affected limb. One dog was non-ambulatory and lacked voluntary movement and sensation in one forelimb. Salter-Harris type II fractures of the distal humerus were diagnosed by radiography in all cases; avulsion of the brachial plexus and pelvic fractures were also present in the non-ambulatory dog. TREATMENT AND OUTCOME: All Salter-Harris type II fractures were stabilised by open reduction and internal fixation with cross pins. One minor complication (seroma) and three major complications (implant migration) developed after surgery. The pins were completely removed in one case and partially removed in two cases to resolve these complications. At the final follow-up examination (12-31 months after surgery), owners reported no lameness in three of the four cases and grade 2/5 left forelimb lameness in one case. CLINICAL RELEVANCE: This type of fracture is rarely described in the literature; however, it should be included in the differential diagnoses of traumatic humeral fractures in growing dogs and cats. In this case series, we achieved fair-to-excellent short-term and long-term outcomes after osteosynthesis of Salter-Harris type II fractures by cross pinning.

Computed tomography assisted determination of optimal insertion points and bone corridors for transverse implant placement in the feline tarsus and metatarsus.

OBJECTIVE: Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus. METHODS: Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA). RESULTS: Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor. CLINICAL SIGNIFICANCE: Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.

BMP-2 delivered from a self-crosslinkable CaP/hydrogel construct promotes bone regeneration in a critical-size segmental defect model of non-union in dogs.

OBJECTIVES: To determine whether the addition of recombinant human bone morphogenetic protein (rhBMP-2) to a self-crosslinkable cellulosic hydrogel/biphasic calcium phosphate (BCP) granules construct promotes bone healing in critical-size ulnar defects in dogs. METHODS: A standardized 2 cm long ulnar ostectomy was performed bilaterally in five dogs to compare bone healing with hydrogel/BCP constructs associated with or without rhBMP-2. Cancellous-bone autografts were used as positive controls in unilateral ulnar defects in five additional dogs. Radiographically, bone healing was evaluated at four, eight, 12, 16 and 20 weeks postoperatively. Histological qualitative analysis with microCT imaging and light and scanning electron microscopy were performed 20 weeks after implantation. RESULTS: All rhBMP-2-loaded constructs induced the formation of well-differentiated mineralized lamellar bone surrounding the BCP granules and bridging bone/implant interfaces as early as eight weeks after surgery. Bone regeneration appeared to develop earlier with the rhBMP-2 constructs than with the cancellous-bone autografts while similar results were obtained at 20 weeks. Constructs without any rhBMP-2 showed osteoconductive properties limited to the bone junctions and a lack of osteoinduction without bone ingrowth within the implantation site. In one dog, the leakage of the hydrogel loaded with rhBMP-2 induced an extensive heterotopic bone formation. CLINICAL SIGNIFICANCE: The addition of rhBMP-2 to a self-crosslinkable hydrogel/BCP construct could promote bone regeneration in a critical-size-defect model with similar performance to autologous bone grafts.

MMP-2 as an early synovial biomarker for cranial cruciate ligament disease in dogs.

OBJECTIVES: To measure the activity of matrix metalloproteinases (MMP)-2 and -9 in synovial fluid from the stifle joints of dogs with cranial cruciate ligament (CrCL) rupture and to compare that to values from contralateral stifle joints and dogs with clinically normal stifle joints. Additionally, the C-reactive protein (CRP) levels were also measured. METHODS: Fourteen large breed dogs with unilateral CrCL rupture and 11 large breed normal dogs were included in this prospective clinical study. Synovial fluid was collected from CrCL-ruptured stifle joints, contralateral clinically normal stifle joints of the same dogs, and stifle joints of normal dogs. Serum was also collected. Synovial fluid activities of MMP-2 and MMP-9 and serum CRP level were measured. RESULTS: The MMP-2 activity in synovial fluid was significantly higher in CrCL-ruptured joints compared to contralateral joints and to stifles from normal dogs. There was no significant difference in activity of MMP-2 in contralateral joints of CrCL-ruptured dogs compared to normal dogs. Both serum CRP level and MMP-9 activity did not differ significantly between the studied conditions. CLINICAL SIGNIFICANCE: It was confirmed that MMP-2 activity is significantly related to CrCL rupture, but there was a failure to demonstrate any significant increase in the contralateral joints compared to the stifle joints of normal dogs. The MMP-2 involvement in progressing CrCL disease still has to be defined.

Comparative use of CO2 laser, diode laser and monopolar electrocautery for resection of the soft palate in dogs with brachycephalic airway obstructive syndrome.

Clinical results, complications and the outcome of using either a carbon dioxide (CO2) laser, diode laser or electrocautery (ELEC) for resection of the soft palate with an extended palatoplasty technique in brachycephalic dogs with upper airway obstructive syndrome were compared. Dogs were randomly allocated into three groups (n=20 in each group): ELEC, diode and CO2 groups. The palatoplasty was made at the rostral aspect of the tonsils. A respiratory clinical score, ranging from 0 (normal) to 4 (cyanosis), was attributed to each dog before surgery and at 0 hours, 24 hours, two weeks and six months after surgery. A favourable outcome was defined as a one point or greater decrease in score 24 hours after surgery. The proportion of dogs with a favourable outcome was significantly higher in the CO2 (n=15) and ELEC groups (n=15) in comparison with the diode group (n=7) (OR=5.6, 95 per cent confidence interval 1.4 to 21.9). Surgical time was significantly shorter (P<0.001; mean [sd] 510 [178] seconds), and bleeding was less common (P<0.001; 30 per cent of cases) in the CO2 group. Complications were most frequent with the diode group (two cases of death and two cases of tracheostomy). The final outcome for all groups (n=57) was considered excellent in 79 per cent of cases and was considered good in 21 per cent.

Two cases of surgically treated feline patellar fractures.

A transverse patellar fracture in a six-month-old cat was successfully treated by figure-of-eight dorsal wiring of the patella. A longitudinal patellar fracture with luxation of a large medial fragment in a 2.5-year-old cat was treated by lateral marginal patellectomy with a positive outcome. While adding material to the few veterinary reports in that species, in this brief communication, the authors discuss the aetiology, diagnosis, and the treatment of the presented cases with regards to findings in previously published feline cases.

Long-term results of upper respiratory syndrome surgery and gastrointestinal tract medical treatment in 51 brachycephalic dogs.

OBJECTIVES: After a first clinical study showing a high prevalence of gastrointestinal tract diseases in brachycephalic dogs presented for upper respiratory syndrome, a prospective study was performed to determine the influence of medical treatment for gastrointestinal tract disorders associated with upper respiratory syndrome surgery. METHODS: The gastrointestinal tract and respiratory disorders of 61 brachycephalic dogs presented for upper respiratory syndrome were evaluated. Together with surgery of the upper respiratory tract, a specific gastrointestinal medical treatment was administered. A minimal follow-up of six months was required for inclusion. RESULTS: Palatoplasty with rhinoplasty was the most common surgical correction (88.5 per cent). The mortality rate in the perioperative period was 3.3 per cent. Minor complications accounted for 26.2 per cent of cases. No aspiration pneumonia was encountered. A sufficient follow-up was obtained in 51 dogs. The improvement was judged by the owners as excellent or good in 88.3 per cent of the respiratory disorders and in 91.4 per cent of the gastrointestinal disorders. Clinically, a statistically significant improvement was obtained for both respiratory and gastrointestinal disorders. CLINICAL SIGNIFICANCE: In comparison with other studies, digestive tract medical treatment combined with upper respiratory surgery seems to decrease the complication rate and improve the prognosis of dogs presented for upper respiratory syndrome.

Prevalence of gastrointestinal tract lesions in 73 brachycephalic dogs with upper respiratory syndrome.

OBJECTIVES: To determine the prevalence of gastrointestinal tract lesions in brachycephalic dogs with upper respiratory tract disease. METHODS: The gastrointestinal tract and respiratory disorders of 73 brachycephalic dogs presented with upper respiratory signs were evaluated. Clinical signs and endoscopic and histological anomalies of the upper digestive tract were analysed. RESULTS: A very high prevalence of gastrointestinal tract problems in brachycephalic dogs presented with upper respiratory problems was observed clinically, endoscopically and histologically. Endoscopic anomalies of the upper digestive tract were present even in dogs without digestive clinical signs. Furthermore, histological evaluation of the digestive tract sometimes showed inflammatory lesions not macroscopically visible at endoscopy. Statistical analysis showed a relationship between the severity of the respiratory and digestive signs. This was significant in French bulldogs, males and heavy brachycephalic dogs. CLINICAL SIGNIFICANCE: These observations show a correlation between upper respiratory and gastrointestinal tract problems in brachycephalic breeds with upper respiratory disease. Surgical treatment of respiratory disease could improve the digestive clinical signs, and/or gastro-oesophageal medical treatment could improve the outcome for surgically treated brachycephalic dogs.

Thoracoscopic pericardectomy performed without pulmonary exclusion in 9 dogs.

OBJECTIVE: To show the feasibility of thoracoscopic pericardectomy without pulmonary exclusion in dogs. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Nine client-owned dogs. METHODS: Dogs referred for the treatment of pericardial effusion by thoracoscopic pericardectomy were intubated with a standard endotracheal tube, mechanically ventilated, and placed in dorsal recumbency. The thoracoscope was introduced into the thorax lateral to the xyphoid process. The operating instruments were inserted at the level of the ventral third of each sixth intercostal space. The pericardium was cut and retrieved through 1 instrument portal. RESULTS: Lung inflation did not interfere with the surgical dissection. A subphrenic pericardectomy was performed in all dogs without iatrogenic trauma. Operative time, from portal placement to skin closure, ranged from 60 to 100 minutes for the first 2 dogs and decreased to 30 to 45 minutes for the latter 7 dogs. CONCLUSIONS: The reported technique avoids the need for selected intubation which requires special tubes, can be technically difficult to perform, and is not recommended in compromised animals in which bilateral lung ventilation is necessary to ensure adequate tissue oxygenation. CLINICAL RELEVANCE: Thoracoscopic pericardectomy offers several advantages over open techniques, including less postoperative pain and morbidity, shorter hospital stay, and improved cosmetic appearance. It can be performed without pulmonary exclusion.

Comparison of allograft/endoprosthetic composites with a step-cut or transverse osteotomy configuration.

This study was designed to compare the biomechanical and functional characteristics of allograft/endoprosthetic composites of the proximal 25% of the femur repaired with either a transverse or a step-cut osteotomy, using a canine model (10 dogs, five with each type of osteotomy). Serial radiography and weight-bearing studies were performed monthly, and mechanical testing was done 6 months after surgery. The femora were tested in torsion and compared with the contralateral control (insertion of a femoral component but no osteotomy). At 6 months, the composites with a step-cut osteotomy had 36% greater structural stiffness than the composites with a transverse osteotomy (p < 0.005) and 121% greater maximum torque at failure than the controls (p < 0.005), without greater structural stiffness. Evaluation of peak vertical ground reaction forces revealed significantly greater weight-bearing on the experimental limb in dogs with a transverse osteotomy. The results of this relatively short-term study were mixed. Despite the increased structural stiffness of the allograft/endoprosthetic composite with a step-cut osteotomy, the dogs with this type of reconstruction had decreased weight-bearing throughout the course of the study. The step-cut osteotomy may augment the stability of the allograft/endoprosthetic composite, allowing faster healing (as demonstrated by the results of mechanical testing), but in some way, not understood, may cause pain in the reconstructed limb. Longer term studies are needed to answer these questions and to determine whether alteration of the traditional transverse osteotomy has any advantage.

Comparison of healing of allograft/endoprosthetic composites with three types of gluteus medius attachment.

This study compared three methods of gluteus medius tendon attachment to an allograft/endoprosthetic composite of the proximal 25% of the femur in a canine model. The three methods were bone to bone, tendon to bone, and tendon to tendon attachment. In an in vivo study, 24 dogs were assigned to three groups of eight dogs each, and serial radiography and weight-bearing analyses were performed throughout the study. The dogs were killed at 6 months, and the specimens were tested in tension to failure and were analyzed histologically. In an in vitro study, each repair was done on six limbs, with a contralateral limb serving as a control for each. In these specimens, the bone to bone attachments were significantly stronger (99.1% of the controls) than the tendon to bone attachments (71.8% of the controls) and the tendon to tendon attachments (40.0% of the controls); there were no differences in tensile stiffness among the three types of attachment. By 6 months, the tensile strength of the tendon to tendon attachments increased significantly and that of the tendon to bone attachments decreased significantly. There were no significant differences in tensile strength among the three types of attachment. The tensile stiffness of the bone to bone attachments (91.0% of the controls) was significantly greater than that of the tendon to bone attachments (40.8% of the controls) but not significantly different from that of the tendon to tendon attachments (63.2% of the controls). The bone to bone attachment was associated with increased bone resorption, bone remodeling, and bone porosity, accompanied by thinner allograft cortices, when compared with the other types of attachment. In dogs with a bone to bone attachment, weight-bearing increased more slowly than in dogs with either of the other two attachments. These changes associated with the bone to bone attachment may merely be secondary to healing of the bone to bone attachment to the greater trochanter; therefore, they may only be temporary phenomena or they may be the portents for long-term complications. Longer term studies of at least 1-2 years must be performed before these questions can be answered.

Ex vivo biomechanics of Kirschner-Ehmer external skeletal fixation applied to canine tibiae.

The purpose of this study was to determine the respective contribution of each of the following parameters to the compressive, bending, and torsional rigidity of the Kirschner-Ehmer (KE) external fixation splint as applied to canine tibiae with an osteotomy gap: bilateral versus unilateral splints; increasing the number of fixation pins; altering the diameter of fixation pins and side bars; decreasing side bar distances from the bone; increasing pin separation distances in each pin group; decreasing distances between pin groups; altering pin clamp orientation; and altering side bar conformation. Bilateral splints were 100% (mean) stiffer than unilateral splints, with stiffness enhanced to the greatest extent in mediolateral bending and torsion. Increasing pin numbers stiffened both bilateral (mean, 41%; 8 versus 4) and unilateral splints (mean, 14%; 8 versus 4). Medium KE splints were 85% (mean) stiffer than small KE splints. Decreasing side bar distances to the bone from 1.5 cm to 1.0 cm to 0.5 cm increased stiffness of both bilateral and unilateral splints by a mean of 13% to 35%. Widening pin spacing from 1.67 cm to 2.5 cm increased stiffness in craniocaudal bending only (56% increase, bilateral splints; 73% increase, unilateral splints). Decreasing the distance between pin groups from 5.84 cm to 2.5 cm increased stiffness in torsion between 23% (unilateral splints) and 45% (bilateral splints) and decreased stiffness of unilateral splints by 29% in craniocaudal bending. Altering pin clamp configuration so that the bolts of the clamp were inside the side bar rather than outside the side bar increased stiffness in axial compression only (73% increase, bilateral splints; 54% increase, unilateral splints). Conforming the lateral side bar to the tibiae increased only axial compressive stiffness by 77% but was no different than placing the clamps inside the side bars of an unconformed bilateral splint. These results quantify the relative importance of specific parameters affecting KE splint rigidity as applied to unstable fractures in the dog.

Evaluation of bovine fibrin sealant in the dog.

Fibrin sealant (human fibrinogen-bovine thrombin) is an effective biodegradable hemostatic agent. However, there is a risk of transmission of infectious viral disease. A new bovine fibrinogen-thrombin sealant (BFTS) was tested for tissue and immune responses in intrathoracic aorta graft in dogs. Intrathoracic aorta replacement was performed in three dogs with a porous Dacron graft presealed with BFTS. Dogs were immunized preoperatively with four dermal applications of BFTS at 9-day intervals. Cellular and humoral immunity to BFTS were determined with lymphocyte blastogenesis test and enzyme-lined immunosorbent assay, respectively. Dogs were necropsied 3 weeks after aortic replacement. Histopathological examination showed that all dogs had a mild inflammatory reaction to the BFTS sealed graft, as expected in response to an inert foreign body. Assay of cellular and humoral immunity to BFTS revealed a low lymphocyte response and a moderate immunoglobulin G (Ig G) response, with no evidence of immediate Ig E (type I) or delayed (type IV) hypersensitivity reaction. We conclude that BFTS causes no adverse tissue response or immunologic reaction when used as a hemostatic agent in the dog even after multiple applications of the material.

Vascular and morphologic changes in canine femora after uncemented hip arthroplasty.

The effects on femoral remodeling of medullary reaming and insertion of a porous endoprosthesis in uncemented hip arthroplasty (UHA) were measured. A unilateral hip hemiarthroplasty (HA) was performed in 12 dogs, with six dogs receiving full-sized and six dogs receiving undersized femoral endoprostheses. A prosthetic head and neck, or acetabular cup, was not implanted. A control group of six dogs underwent femoral head and neck excision (FHNE) only. All dogs were killed 4 weeks after the surgical procedure. Porosity, vascularity, and bone formation were quantified in each femur of the dogs that had been operated on and in each femur of two unoperated dogs. Full-sized did not differ from undersized HA bones in vascularity, porosity, or bone formation. Femurs in which hemiarthroplasties had been performed (full-sized and undersized) had a three-fold increase in porosity, vascularity, and bone formation compared to the contralateral and the FHNE femurs. Changes in porosity and vascularity were greatest (p < .05) at the metaphyseal level and in the medial and caudal quadrants. There was a strong correlation (R2 0.77 to 0.93, and p = .0001) between the increase in porosity and vascularity. These results support the hypothesis that medullary reaming followed by uncemented prosthetic stem implantation contribute to remodeling of the proximal portion of the femur after UHA.