While new biomaterials for regenerative therapies are being reported in the literature, clinical translation is slow. Some existing regenerative approaches rely on high doses of growth factors, such as bone morphogenetic protein‐2 (BMP‐2) in bone regeneration, which can cause serious side effects. An ultralow‐dose growth factor technology is described yielding high bioactivity based on a simple polymer, poly(ethyl acrylate) (PEA), and mechanisms to drive stem cell differentiation and bone regeneration in a critical‐sized murine defect model with translation to a clinical veterinary setting are reported. This material‐based technology triggers spontaneous fibronectin organization and stimulates growth factor signalling, enabling synergistic integrin and BMP‐2 receptor activation in mesenchymal stem cells. To translate this technology, plasma‐polymerized PEA is used on 2D and 3D substrates to enhance cell signalling in vitro, showing the complete healing of a critical‐sized bone injury in mice in vivo. Efficacy is demonstrated in a Münsterländer dog with a nonhealing humerus fracture, establishing the clinical translation of advanced ultralow‐dose growth factor treatment.

The aim of this study was to investigate the short- and long-term morbidity and mortality associated with urethral rupture in cats. Medical records were reviewed from four veterinary hospitals. Diagnosis was made from retrograde urethrography or direct visualisation during surgery. Location of rupture was categorised as pre-, intra- or post-pelvic. Follow-up data were collected from referring veterinarians. Sixty-three cats were included in the study of which, males predominated (88.9%). Trauma was the most common cause (n = 35; 55.6%) with the remainder due to iatrogenic injury. Forty-eight cats (88.9%) were treated surgically and six (11.1%) managed conservatively. Significant differences between cats suffering traumatic versus iatrogenic injury included the presence of musculoskeletal injuries (P <0.001); the location of rupture (P <0.001); the degree of rupture (P <0.001); definitive management (P <0.001) and short-term complications (P = 0.026). Short-term complications were significantly associated with the following: musculoskeletal injuries (P = 0.012); uroabdomen/uroretroperitoneum (P = 0.004); azotaemia (P = 0.021); postoperative urinary diversion (P = 0.036) and >1 surgery performed (P = 0.006). Forty-seven cats (74.6%) survived to discharge. Prognostic factors associated with survival to discharge included the presence of musculoskeletal injuries (P = 0.017); cause of rupture (P = 0.017); location of rupture (P = 0.039) and definitive management (P = 0.020). Twenty-four cats (57.1%) suffered short-term complications and 10 (27.0%) suffered long-term complications. Of those cats surviving to discharge 30 (71.4%) had a good outcome. Median follow-up was 16 months. Outcome was significantly associated with cause of rupture (P = 0.04); short-term complications (P = 0.03) and long-term complications (P <0.001). In conclusion, a significantly greater proportion of cats with iatrogenic injuries survived to discharge and had a good outcome compared with those that suffered trauma.

K-wires can be used successfully as alignment aids during CCWO and help to create a significantly more orthogonal osteotomy. This allows a significant reduction in the difference between the preoperative and postoperative angles of valgus or varus, which may reduce the risk of developing a clinically important iatrogenically introduced valgus/varus deformity postoperatively.

ObjectivesThe aim of this study was to evaluate the repeatability of quantitative sensory tests (QSTs) in a group of healthy untrained cats (n = 14) and to compare the results with those from cats with osteoarthritis (n = 7).MethodsPeak vertical force (PVF) and vertical impulse were measured on a pressure plate system. Thermal sensitivity was assessed using a temperature-controlled plate at 7°C and 40°C. Individual paw lifts and overall duration of paw lifts were counted and measured for each limb. Paw withdrawal thresholds were measured using manual and electronic von Frey monofilaments (MVF and EVF, respectively) applied to the metacarpal or metatarsal pads. All measurements were repeated twice to assess repeatability of the tests.ResultsIn healthy cats all tests were moderately repeatable. When compared with cats with osteoarthritis the PVF was significantly higher in healthy hindlimbs in repeat 1 but not in repeat 2. Cats with osteoarthritis of the forelimbs showed a decrease in the frequency of paw lifts on the 7°C plate compared with cats with healthy forelimbs, and the duration of paw lifts was significantly less than healthy forelimbs in the first repeat but not in the second repeat. Osteoarthritic limbs had significantly lower paw withdrawal thresholds with both MVF and EVF than healthy limbs.Conclusions and relevanceQSTs are moderately repeatable in untrained cats. Kinetic gait analysis did not permit differentiation between healthy limbs and those with osteoarthritis, but thermal sensitivity testing (cold) does. Sensory threshold testing can differentiate osteoarthritic and healthy limbs, and may be useful in the diagnosis and monitoring of this condition in cats in the clinical setting.

Practical relevance: Periarticular stifle fractures are uncommon but challenging injuries to treat. There may be concurrent damage to the ligaments and stabilising structures of the stifle joint itself, which should also be evaluated (see Part 1 of this article series). Improved knowledge of the fixation options and biomechanical challenges of these injuries will aid clinical decision-making and effective repair. Clinical challenges: Due to their nature, periarticular fractures may have small juxta-articular fragments, which require additional thought to address during stabilisation. In juvenile animals, these fractures typically involve the physis and often can be managed with cross pin fixation. In adult cats, locking fixation, specialised plates or external skeletal fixators can be utilised to address the juxta-articular fragments. Readers should also be aware of patellar fracture and dental anomaly syndrome (PADS), where cats develop insufficiency fractures affecting the patella and proximal tibia. A careful oral examination should be performed in affected patients, as these cats may have persistent deciduous teeth. Close attention should be paid to preoperative radiographs for evidence of chronicity of the injury including sclerosis of the patella, remodelling and blunting of the fracture lines. Aims: The aims of the article are to review the current literature surrounding periarticular fractures of the stifle joint and to summarise the diagnosis, treatment, outcome and complications of each fracture type. As well as discussing general fracture fixation and biomechanical principles applicable to both dogs and cats, information is provided on specific issues facing cats, such as PADS. Evidence base: Published data is limited, with reports including only a small number of cats. The information and recommendations in this article have therefore been drawn from a combination of the available literature and the authors’ clinical experience.