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Current strategies for bone regeneration after traumatic injury often fail to provide adequate healing and integration. Here, we combined the poly (ethylene glycol) diacrylate (PEGDA) hydrogel with allogeneic "carrier" cells transduced with an adenovirus expressing BMP2. The system is unique in that the biomaterial encapsulates the cells, shielding them and thus suppressing destructive inflammatory processes. Using this system, complete healing of a 5 mm-long femur defect in a rat model occurs in under 3 weeks, through secretion of 100-fold lower levels of protein as compared to doses of recombinant BMP2 protein used in studies which lead to healing in 2-3 months. New bone formation was evaluated radiographically, histologically, and biomechanically at 2, 3, 6, 9, and 12 weeks after surgery. Rapid bone formation bridged the defect area and reliably integrated into the adjacent skeletal bone as early as 2 weeks. At 3 weeks, biomechanical analysis showed the new bone to possess 79% of torsional strength of the intact contralateral femur. Histological evaluation showed normal bone healing, with no infiltration of inflammatory cells with the bone being stable approximately 1 year later. We propose that these osteoinductive microspheres offer a more efficacious and safer clinical option over the use of rhBMP2., (Copyright © 2013 Orthopaedic Research Society.)

Objective: To evaluate the presence of residual disc material within the vertebral canal following hemilaminectomy in chondrodystrophic dogs with thoracolumbar intervertebral disc disease., Methods: Forty dogs were treated by hemilaminectomy. Computed tomography was performed preoperatively and immediately postoperatively. The vertebral canal height, width, area, and herniated disc material area were measured. Maximum filling percentage (MFP), residual disc percentage (RDP), maximum residual filling percentage (MRFP), and residual filling percentage (RFP) were calculated. Clinical outcome was determined by telephone interviews., Results: Residual disc material was present in 100% of the dogs. Mean MFP = 55.4% (range 25.9-82.3%; median 56.9%). Mean RDP = 50.3% (range 2.6-155.8%; median 47.9%). Mean MRFP = 30.8% (range 4.9-60%; median 30.1%). Mean RFP = 19.8% (range 4.8-45%; median 19.0%). All dogs were ambulatory with voluntary urination at the long-term follow-up (range: 88-735 days)., Clinical Significance: Residual disc was present in all dogs following hemilaminectomy for intervertebral disc disease. Residual disc was not associated with failure to achieve functional recovery in these cases.

Objective: To evaluate inter- and intraobserver variability in the measurement of distal tibial axis/proximal tibial axis angle (DPA) from lateral radiographs of canine tibia in dogs with cranial cruciate ligament rupture (CCLR)., Study Design: Retrospective clinical study., Animals: Dogs (n=100) with cranial cruciate ligament rupture., Methods: Medical records of dogs diagnosed with CCLR were reviewed. In addition to signalment and TPA measurements, measured DPA (mDPA) was calculated for each lateral view of the tibia in each animal, twice, by 3 blinded observers. Subjective scoring of DPA (sDPA) was also recorded, twice, by 3 additional blinded observers from lateral views of the proximal half of the tibia in each dog. Inter- and intraobserver variability was measured by intraclass correlation coefficient (ICC) for each measurement. Correlation between mDPA and sDPA was also determined., Results: Median tibial plateau angle (TPA) of the subject population was 27.9° (range 18.8-41.3°; IQR: 25.5-30.75°). Mean ± SD mDPA was 6.50 ± 2.81° (confidence intervals [CI]: 5.94-7.06°; range 0-13.33°). There was no correlation between age and weight of dogs and the mDPA (P=.58 and .12). There was a moderate correlation between mDPA and TPA (r(2)=0.49, P<.0001). There was a moderate correlation between sDPA and mDPA (r(2)=0.27, P<.0001). Good inter- and intraobserver agreement was found in the measurement of mDPA., Conclusion: mDPA is a reproducible measurement of caudal angulation of proximal tibia. Furthermore, mDPA of dogs with cranial cruciate ligament disease in this report are in concordance with previous reports., (© Copyright 2011 by The American College of Veterinary Surgeons.)

Objectives: To describe the clinical outcome of a 4 pin lumbosacral fixation technique for lumbosacral fracture-luxations, and to refine placement technique for iliac pins based on canine cadaver studies., Study Design: Retrospective and anatomic study., Sample Population: Dogs (n=5) with lumbosacral fracture-luxations and 8 cadaveric canine pelvi., Methods: Lumbosacral fracture-luxations were stabilized with a 4 pin (positive-profile threaded) and bone cement fixation. Caudal pins were inserted in the iliac body and cranial pins were inserted into the L7 or L6 pedicle and body. Follow-up examinations and radiographs were performed to assess patient outcome. Intramedullary pins were inserted into the iliac bodies of 8 cadaver pelvi. Radiographs were taken to measure pin insertion angles and define ideal insertion angles that would maximize pin purchase in the ilium., Results: Follow-up neurologic examination was normal in 4 dogs. Radiographic healing of the fracture was evident in 5 dogs. One implant failure occurred but did not require re-operation. For cadaver iliac pins, mean craniocaudal insertion angle was 29 degrees and mean lateromedial insertion angle was 20 degrees., Conclusions: Four pin and bone cement fixation effectively stabilizes lumbosacral fracture luxations. The iliac body provides ample bone stock, which can be maximized using an average craniocaudal pin trajectory of 29 degrees and an average lateromedial pin trajectory of 20 degrees., Clinical Relevance: Lumbosacral fracture-luxations can be stabilized with 4 pin and bone cement fixation in the lumbar vertebrae and iliac body, using 29 and 20 degrees as guidelines for the craniocaudal and lateromedial pin insertion angles in the ilium.