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Objectives: The aim of this study was to evaluate ground reaction forces (GRFs) in cats after unilateral total hip replacement (THR) and compare them with cats after femoral head and neck ostectomy (FHO)., Methods: The databases of the Small Animal Clinic of the Veterinary University in Vienna and three referral clinics were searched for cats that had undergone unilateral THR with the BioMedtrix Micro total hip system or FHO more than 6 months previously. Owners were invited to complete a survey and bring their cats for re-examination, inlcuding clinical and orthopaedic examinations, hip radiography and a gait analysis using a pressure-sensitive plate., Results: Nine cats were included in each group. Cats after THR showed larger GRF values (peak vertical force [PFz] and vertical impulse [IFz] normalised to total force [%TF]) on the operated limb. The resulting symmetry indices (SIs) were lower in terms of vertical force in 7/9 (78%) cats and vertical impulse in 6/9 (67%) cats between the hindlimbs in cats after THR compared with FHO - SI (PFz) = 3.31% ± 2.19% (THR) vs 4.84% ± 2.99% (FHO) and SI (IFz) = 5.17% ± 3.66% (THR) vs 8.27% ± 3.12% (FHO). Cats after FHO showed significantly lower muscle circumference and range of motion (ROM) at the operated hindlimb compared with the contralateral side, whereas cats after THR showed no statistically significant differences between their hindlimbs. Owner surveys revealed significant differences in their subjective assessment of activity and change in gait between the two groups, with better values for cats after THR., Conclusions and Relevance: This was the first study that measured GRFs in cats after THR. PFz (%TF) and IFz (%TF) values were higher in the operated limb of the THR group than in those of the FHO group, resulting in lower symmetry indices (indicating better symmetry) and better loading of the corresponding hindlimb. This finding is clinically relevant and can help in making decisions regarding the treatment of hip joint pathologies in cats., Competing Interests: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: This literature review aims to provide an overview of the existing literature on intraosseous transcutaneous amputation prosthesis (ITAP) and stump socket prosthesis in amputated animals. The goal is to compare the advantages and disadvantages of ITAP with exoprosthesis use, given the importance of limb-sparing procedures in contemporary veterinary medicine., Materials and Methods: A systematic research adhering to the PRISMA protocol was conducted using a time span from 2000 to 2023, focusing on papers detailing the clinical application of ITAP or exoprosthesis in small animals., Results: This review encompasses 8 studies, 5 of them offering insights into the use of exoprosthesis in dogs and cats and 3 into ITAPs. Among the patients receiving an ITAP, 2 out of 6 experienced complications such as implant loosening and breakage. Studies on stump socket prostheses identified 10 different complications, occurring 93 times in 96 canine patients, with some patients showing more than one complication. However, in the studies assessing the quality of life, 31 out of 48 owners reported that their dogs had a good or excellent quality of life post-surgery., Conclusion: Both approaches have their pros and cons. Stump socket prostheses may offer better adaptability and simpler application, but owners must be vigilant about daily maintenance to prevent pressure sores or infections, often necessitating adaptations due to stump changes. In contrast, ITAP avoids these complications but requires assurance of proper skin and bone integration. The positive aspect of both prosthesis types lies in restoring quadrupedal gait, alleviating strain on other limbs and maintaining physiological posture, particularly crucial for animals with preexisting conditions. It is crucial to carefully evaluate the outcomes and potential complications of each prosthesis type, prioritizing the patient's well-being., Clinical Relevance: Limb amputation is an important decision in veterinary medicine, where alternative options beyond total limb amputation should be thoroughly discussed. Partial limb amputation, along with prosthetic devices, can greatly benefit patients, provided careful consideration and planning are undertaken., Competing Interests: The authors affirm that there are no conflicts of interest to declare for this study., (Thieme. All rights reserved.)

Background: Small-bore wire-guided thoracostomy tubes (SBWGTT) are commonly used in cats to manage pleural disease and generally have a low complication rate. Our study aimed to explore the correlation between recumbency of cats, placement method, and the occurrence of insertional complications to identify risk factors during SBWGTT placement. In this experimental cadaveric study, SBWGTT placement using a modified Seldinger technique was conducted in 24 feline cadavers. Cats, euthanized for reasons unrelated to the study, were randomly assigned to pleural effusion (EFF; n = 12) and pneumothorax (PNEU; n = 12) groups. Each cadaver was intubated and ventilated with a peak inspiratory pressure (PIP) of 10 mmHg, and sterile saline or air was instilled into the thorax over a 5 mm thoracoscopic trocar in the fourth intercostal space (ICS). Instillation was stopped when the lateral thoracic wall to lung distance (TWLD) reached 10 to 12 mm, measured with ultrasound in the favorable position. Sternal recumbency was the favorable position for the EFF group, and lateral recumbency for the PNEU group. Following the placement of the first SBWGTT in each group, the cadavers were positioned unfavorably (lateral recumbency for EFF group, sternal recumbency for PNEU group), and a second drain was introduced contralaterally. A bilateral 8th ICS thoracotomy was then performed to visually assess intrathoracic structures and drain integrity. A binary logistic regression mixed model was conducted to determine interaction between the induced condition and body position., Results: A total of 48 SBWGTTs were placed, with complications observed in 33.3% (8/24) of cases. Five of these were major complications consisting of lung lacerations. Complications were more common in the unfavorable position, accounting for 75% of cases, although this result was not statistically significant. The odds of complication rates were > 70% in the unfavorable position and decreased with an increase in TWLD (< 30%)., Conclusion: Complications associated with SBWGTT placement are influenced by recumbency, although the data did not reach statistical significance. Placing cats in lateral recumbency for pneumothorax treatment and sternal recumbency for pleural effusion treatment may reduce insertional complications., (© 2024. The Author(s).)

Background: Various trochleoplasty techniques, including trochlear wedge recession (TWR) and trochlear block recession (TBR), are used to treat dogs with medial patellar luxation (MPL). However, the objective outcomes of these surgical procedures are underreported., Methods: Medical records were obtained for dogs weighing less than 10 kg that underwent either TWR or TBR and tibial tuberosity transposition to address grade I-III MPL. Long-term (at least 1 year after the last procedure) follow-up included orthopaedic and radiographic examinations, such as osteoarthritis score (OAS), ground reaction force (GRF) analysis and canine brief pain inventory (CBPI)., Results: Overall, 20 dogs (26 stifles) were followed up in the long term. Minor postoperative complications, medial patellar reluxation (MPR) and intermittent lameness occurred in 46.15%, 19.23% and 15% of the dogs, respectively. MPR occurred only in TWR-treated stifles, while mean OAS increased in all groups. Using the CBPI, the owners perceived an excellent or very good outcome in 95% of dogs., Limitations: The limitations of the study include its retrospective observational nature, a lack of randomisation and a small sample size., Conclusion: Surgical treatment resulted in a favourable outcome. GRF analysis could detect subtle differences in weight bearing in dogs treated for MPL, which might not be apparent clinically. There might be a higher risk for reluxation for TWR. However, a larger-scale prospective study would be required to find which treatment is superior., (© 2024 The Authors. Veterinary Record published by John Wiley & Sons Ltd on behalf of British Veterinary Association.)

Background: This study evaluated joint stability after surgical repair of cranial cruciate ligament (CrCL)-deficient stifle joints in cats using a novel absorbable polylactide bone anchor in an ex vivo model., Methods: Thirty-six hindlimbs from cats with intact (G i group) and transected CrCLs were treated with fabellotibial suture alone (G FW group), suture combined with an absorbable polylactide bone anchor (G WD group), or suture combined with a nonabsorbable bone anchor (G FT group), positioned in a limb press with predefined joint angles (stifle joint: 120 ± 5°; hock joint: 120 ± 5°) and loaded with 10%, 20%, and 30% of body mass (BM). Predefined points were measured on lateral radiographs and with a coordinate measurement machine. Distances on radiographs (mm) were measured and angles (°) were calculated to represent the craniocaudal movement and the internal rotation of the tibia., Results: There were no differences for craniocaudal movement between G i and G FW or G FT , but for G WD regarding angle measurement at 30% BM. For internal rotation, there was no significant difference between G i and G FW or G WD , but for G FT ., Conclusion: The used absorbable polylactide bone-anchor was able to stabilize the stifle joint regarding internal rotation and craniocaudal movement as calculated from distance measurements.

Objectives: The objective of this study was to compare ground reaction forces (GRFs) of a group of cats after femoral head and neck ostectomy (FHO) with those of a historical control group., Methods: We searched the database of the Small Animal Clinic of the Veterinary University in Vienna for cats that had undergone unilateral FHO at least 1 year previously. Owners were telephoned and invited to the clinic with their cats for a re-examination. An in-house owner questionnaire-based evaluation, complete orthopaedic examination, hip radiography and gait analysis with a pressure-sensitive plate were performed, and results were compared within and between groups (FHO group and control group [CG])., Results: Seventeen cats that had undergone FHO (FHO group) at least 1 year previously and 15 healthy cats (CG) from a previous study were included. Measured GRFs (peak vertical force and vertical impulse [IFz] normalised to total force [%TF]) of the FHO legs were lower than those of the other legs of the FHO group and the legs of the CG. Results of the owner questionnaire were generally good and did not match the results of the GRF comparison. Furthermore, the gaits evaluated during the orthopaedic examination did not correlate with the measured GRFs where we identified a certain degree of lameness (reduced IFz, %TF) in all cats. Cats with limb shortening (dorsally displaced major trochanter major) were not revealed to have different GRF measurements., Conclusions and Relevance: This is the first study to assess GRFs in a large group of cats that had undergone FHO, comparing findings with those in healthy cats. Even if the differences are statistically significant, but rather small, our findings point to a long-term residual gait abnormality that could be detected using a pressure-sensitive plate but not always with an orthopaedic examination, in cats 1 year after FHO.

Objectives: The aim of our study was to compare the standard fabellotibial suture with Mini TightRope fixation for the treatment of a cranial cruciate ligament (CCL) rupture using a feline custom-made limb press., Methods: Cadaveric hindlimbs of 10 cats were inserted in the limb press at predefined joint angles and loads of 10% and 30% body weight (BW) were applied. Mediolateral radiographs were taken and three-dimensional coordinates were recorded using a microscribe digitiser, with intact and transected CCLs and after either fabellotibial suture or Mini TightRope fixation were performed. Different distances and angles from radiographs or microscribe coordinates were analysed., Results: Radiographic distances from the femoral condyle to the cranial edge of the tibia (X1-X2) were higher in CCL-deficient stifles than in intact stifles at 10% and 30% BW loads. All fabellotibial sutures and Mini TightRope fixations neutralised excessive cranial tibial thrust. A significant difference in the distance between the patella and tibial tuberosity (D2) was observed between CCL-deficient limbs and Mini TightRope-fixed limbs at 10% BW load ( P <0.04). A significant difference in the distance between the tibial tuberosity and lateral collateral ligament of the femur (D3) was observed between the intact and transected CCLs on the left legs at 10% BW load ( P <0.003) and on both legs at 30% BW load ( P <0.002). Furthermore, we observed significant differences between CCL-deficient left legs and Mini TightRope-treated legs at 10% BW load ( P <0.003). With regard to fabellotibial suture-treated legs, we observed significant differences between transected limbs and fixed limbs at 30% BW load ( P <0.004). W1 (craniocaudal angle) and W2 (mediolateral angle) showed significant differences between intact and transected CCLs and between transected and fixed limbs at 30% BW load ( P <0.004)., Conclusions and Relevance: Fixation of CCL-deficient stifles with lateral fabellotibial suture, as well as Mini TightRope tightened with a 20 N load, produces good biomechanical stability, as detected via radiographic assessment.

Rapid developments in Regenerative Medicine and Tissue Engineering has witnessed an increasing drive toward clinical translation of breakthrough technologies. However, the progression of promising preclinical data to achieve successful clinical market authorisation remains a bottleneck. One hurdle for progress to the clinic is the transition from small animal research to advanced preclinical studies in large animals to test safety and efficacy of products. Notwithstanding this, to draw meaningful and reliable conclusions from animal experiments it is critical that the species and disease model of choice is relevant to answer the research question as well as the clinical problem. Selecting the most appropriate animal model requires in-depth knowledge of specific species and breeds to ascertain the adequacy of the model and outcome measures that closely mirror the clinical situation. Traditional reductionist approaches in animal experiments, which often do not sufficiently reflect the studied disease, are still the norm and can result in a disconnect in outcomes observed between animal studies and clinical trials. To address these concerns a reconsideration in approach will be required. This should include a stepwise approach using in vitro and ex vivo experiments as well as in silico modeling to minimize the need for in vivo studies for screening and early development studies, followed by large animal models which more closely resemble human disease. Naturally occurring, or spontaneous diseases in large animals remain a largely untapped resource, and given the similarities in pathophysiology to humans they not only allow for studying new treatment strategies but also disease etiology and prevention. Naturally occurring disease models, particularly for longer lived large animal species, allow for studying disorders at an age when the disease is most prevalent. As these diseases are usually also a concern in the chosen veterinary species they would be beneficiaries of newly developed therapies. Improved awareness of the progress in animal models is mutually beneficial for animals, researchers, human and veterinary patients. In this overview we describe advantages and disadvantages of various animal models including domesticated and companion animals used in regenerative medicine and tissue engineering to provide an informed choice of disease-relevant animal models., (Copyright © 2020 Ribitsch, Baptista, Lange-Consiglio, Melotti, Patruno, Jenner, Schnabl-Feichter, Dutton, Connolly, van Steenbeek, Dudhia and Penning.)

Detection of lameness in cats can be very time-consuming and frustrating. Feline studies have shown that the success of treatment can be evaluated by measurement of the ground reaction force (GRF). However, the possibility of multiple limb involvement or the presence of a compensatory mechanism has not been investigated. Furthermore, there has been no research in cats on possible differences in GRFs between those with stifle problems and those with hip problems, as reported in dogs. In this study, we compared temporospatial parameters and GRFs in 20 lame cats after femoral head and neck ostectomy (FHO) or stifle disease to those in 15 healthy cats. An orthopedic examination was performed in all cats and radiographs were obtained to confirm the disease. GRFs, including peak vertical force (PFz), vertical impulse (IFz), time to PFz, and temporospatial parameters, including step length, paw contact area, and stance phase duration, were calculated. We also calculated the symmetry index (SI) in the forelimbs and hind limbs. The GRFs were normalized to total force (% TF). We found that the IFz (% TF) and PFz (% TF) were lower in the affected limb than in the other limbs in the lame cats. When the lame cats were compared with the sound cats, this difference was only significant for IFz (% TF). The SI values for the PFz and IFz were significantly higher in the hind limbs than in the forelimbs in the lame cats group but there was no difference in the SI according to whether the problem was in the hip or stifle. There were also differences in stance phase duration and paw contact area in both the forelimbs and hind limbs between the sound group and the lame group. There was no difference in PFZ (% TF) or IFZ (% TF) in the affected limb between the lame cats with stifle and those after FHO; however, there were changes in time to PFz and step length. In conclusion, mild to moderate lameness can be detected and measured in cats using pressure plates. The compensatory mechanisms in cats at a walk appear to involve shifting the weight to the other three legs without favoring either the contralateral or the diagonal limb., Competing Interests: The authors have declared that no competing interests exist.

Current research on gait analysis mostly involves horses and dogs. Feline kinetics and kinematics are being investigated and receiving more clinical interest at present. Ground reaction forces measured on pressure-sensitive mattresses have been established in healthy Domestic Shorthair cats (DSH). Currently, no further information exists on either breed-specific measured gait reaction forces or comparisons among breeds. Because Maine Coon (MC) cats appear to be over-represented with orthopaedic diseases of the hind limb (hip dysplasia, patellar luxation), we evaluated ground reaction force GRF measurements in MC cats and compared them with those of DSH cats. Pre-evaluation radiological and clinical exams determined that the cats were not lame. The parameters evaluated were peak vertical force (PFz), vertical impulse (IFz), time to PFz (TPFz), step length (SL), paw contact area (PCA), stance phase duration (SPD) and symmetry index (SI) for the fore- and hind limbs. In both breeds, PFz and IFz were greater in forelimbs than in hind limbs. The PFz and IFz in Newtons were higher in the MC cats compared to the DSH cats, but not after normalisation for total force (%TF) and body mass (%BM). Furthermore, due to their body conformation, MC cats have a longer SL, larger PCA, and higher body weight than DSH cats. No other parameters differed significantly, except that the TPFz displayed an earlier value in the MC hind limbs. Measured symmetry indices were similar to those reported in dogs and did not differ between breeds. This is the first study to report GRF values and temporospatial parameters in a healthy MC cat population. However, our results could not confirm differences between normalized PFz and IFz and temporospatial parameters between the breeds. The authors therefore conclude that genetic or other causes may be involved in orthopaedic hind limb pathogenesis seen in MC cats more often than in other breeds., Competing Interests: The authors have declared that no competing interests exist.

Objective: The optimal surgical technique for treatment of cranial cruciate ligament rupture in canine has been scientifically discussed for decades. Despite the continuous debate, proximal tibial osteotomies such as tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA) are increasingly common. The objective of this review was to systematically evaluate the literature reporting outcome and complications associated with TPLO and TTA., Materials and Methods: A systematic search of literature databases identified articles published from August 2004 to February 2016 describing evaluations of short- or longterm outcomes as well as complications following TPLO or TTA., Results: Ninety-one studies were included in this review and assigned to one out of four evidence levels. Of those, 89 studies provided the lowest evidence level and only two were assigned to the third-best evidence level. A comparison of subjective gait analyses could not detect differences in the decrease of lameness between TPLO and TTA, while objective gait analysis supports the superiority of TPLO. Fewer patients treated with TPLO were diagnosed with postoperative joint instability and TPLO had a lower percent increase of osteoarthritis (OA) after surgery. Owner satisfaction was high for both techniques. For TPLO and TTA the average total, minor, major and catastrophic complication rates were 15.9 % and 20.8 %, 7.9 % and 11.6 %, 5.2 % and 13.2 % as well as 0.8 % and 5.6 %, respectively., Conclusion and Clinical Significance: The assessed literature supports the hypothesis that TPLO is associated with lower complication rates, an improved clinical-functional outcome and less increase of OA compared to TTA. The results are indicative for a long-term restoration of normal limb function after TPLO. However, the strength of available evidence and the comparability of each study's results were poor and more comparative studies are needed to draw strong conclusions towards the superiority of the TPLO over the TTA., Competing Interests: The authors declare not to have any conflicts of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

Objectives This study aimed to compare the under-and-over technique, a type of intracapsular treatment, and the standard fabella-tibial suture, a method for extracapsular treatment, in achieving immediate, postoperative stifle stability after cranial cruciate ligament (CrCL) rupture by using a feline, custom-made limb-press model. Methods Cadaveric feline hindlimb specimens (n = 14) were positioned in the limb press at predefined joint angles (stifle joint: 120°; hock joint: 120°), and vertical loads of 5%, 10%, 20% and 30% body weight were applied statically. Mediolateral radiographic views were obtained of the stifles under each load before and after CrCL transection, as well as after treatment with either of the two surgical techniques, and differences in distance between two predefined radiographic points for each radiograph were analysed. Results The general linear model showed a significant effect of load ( P <0.01) and technique ( P = 0.004) and a significant interaction between load and technique ( P = 0.006) regarding craniocaudal stifle stability. Distances between predefined tibial and femoral reference points were consistently higher in transected CrCLs than in intact stifles. All standard fabella-tibial suture-treated stifles (n = 7) were stable at all loads tested. Of the seven under-and-over technique-treated stifles, one was unstable at 20% body weight load and three at 30% body weight load. Conclusions and relevance Our model, which appropriately reproduced certain aspects of domestic shorthair cat stifle mechanics, indicated that a 40 lb monofilament nylon prosthesis, tightened at 20 N, produces more favourable biomechanical stabilisation of craniocaudal cruciate-related stifle instability than a 0.5 cm wide strip of fascia lata applied intracapsularly.

Objectives  To evaluate the intra- and inter-observer measurement variability of an existing osteoarthritis (OA) stifle scoring system. Methods  Paired caudocranial and mediolateral canine stifle radiographs were selected randomly. A total of 15 assessment points were evaluated independently and graded twice (integer numeric scale: 1-4) at an interval of 2 weeks by three observers with different levels of experience. The grades for each of the 15 factors were summed to obtain the OA score for each patient. Results  The 15 independent assessment points measured by the three observers showed high reproducibility and low intra-observer variability. Inter-observer variability was also low (mean: 1.09 ± 4.99, 95% CI [confidence interval]: -0.35 to 2.55). The most discordant ratings among the three observers involved sesamoid bones of gastrocnemius muscle (assessment point 11 of 15) and popliteal surface of femur (assessment point 10 of 15). Clinical Significance  A validated and feasible OA scoring method is prerequisite for reliable radiographic assessment of OA progression. The low overall inter- and intra-observer variabilities among the 15 independent measures of the OA scoring system presented herein support its feasibility for application in clinical practice as an objective tool for radiographic scoring of stifle OA., Competing Interests: Conflict of Interest: The authors do not have any potential conflicts of interest to declare., (Schattauer GmbH Stuttgart.)

Objectives The aim of this study was to examine histologically intact and ruptured cranial cruciate ligaments in cats, in order to evaluate whether degeneration is a prerequisite for rupture. Methods We performed a histological examination of 50 intact and 19 ruptured cranial cruciate ligaments in cadaver or client-owned cats, respectively, using light microscopy. Cats with stifle pathology were further divided into five age groups in order to investigate the relationship of changes in the ligament with lifespan. Cats with ruptured cranial cruciate ligaments were divided into two groups according to medical history (with presumed history of trauma or without any known history of trauma) in order to investigate the relationship of ligament rupture with a traumatic event. Data from 200 healthy cats were selected randomly and reviewed to make a statistical comparison of cats with and without cranial cruciate ligament rupture (reference group). Results On histological examination, the intact cranial cruciate ligaments showed basic parallel arrangement of the collagen fibres, with no relation to age. While cats of a more advanced age showed fibrocartilage in the middle of the cranial cruciate ligament - a likely physiological reaction to compression forces over the lifespan - degenerative changes within the fibrocartilage were absent in all cases, regardless of age or rupture status. Cats suffering from cranial cruciate ligament rupture without history of trauma were significantly older than cats in the reference group. Conclusions and relevance This study showed that differentiation of fibrocartilage in the middle of the cranial cruciate ligament is likely a physiological reaction to compressive forces and not a degenerative change associated with greater risk of rupture in advanced age. This finding in cats is distinct from the known decrease in differentiation of fibrocartilage in dogs with cranial cruciate ligament rupture. Furthermore, the histological examination of cats revealed no other signs of degeneration in the cranial cruciate ligaments. Thus, degeneration is likely not an aetiological factor for cranial cruciate ligament rupture in cats.

Gait analysis has been extensively performed in dogs and horses; however, very little is known about feline biomechanics. It was, therefore, the aim of this study to determine the coefficient of variation (CV) among three ground reaction force (GRF) measurements taken for 15 client-owned European shorthaired cats without a training period and a short acclimatisation time. Gait was measured as each cat walked across a pressure-sensitive walkway, and measurements were made three times over a multi-week period (range: 2 to 17 weeks). The parameters evaluated were peak vertical force (PFz), vertical impulse (IFz), stance phase duration (SPD), step length (SL), paw contact area (PCA) and symmetry index (SI%) of the front and hind limbs. After averaging each of the values from the three measurements, the CV and 95% confidence interval (CI) were calculated for all parameters. PFz showed the lowest CV (~ 3%), while IFz showed the highest CV (~11%) when normalised to body mass. When the GRFs were normalised to total force, the CV of PFz dropped to ~2% and that of IFz dropped to ~3%. The CV of SL and PCA were lower (~6% respectively ~5%) compared to the CV for SPD (~10%). The SI% for both PFz and IFz were comparable to the values reported in the gait analysis literature for dogs. Results of the current study indicate that gait analysis of cats using pressure-sensitive walkways produces reliable data and is a promising approach for evaluation of lameness. The results also suggest that PFz may be a more reliable parameter than IFz and that normalisation to percent of total force may aid in interpretation of the evaluated data.