Use of a Custom-Made Patellar Groove Replacement in an American Staffordshire Terrier Puppy with a Severe Bone Defect in the Femoral Trochlea Caused by Hematogenous Osteomyelitis.

An 8-month-old male American Staffordshire terrier was referred for a no-weightbearing lameness of the right pelvic limb, hyperthermia, lethargy and inappetence. Two months before, endocarditis was diagnosed and treated in another veterinary hospital. Orthopedic, radiographic and tomographic examinations revealed a bone sequestrum of 4 × 1.4 cm and active periosteal reaction of the caudo-lateral cortical in the metaphysis and the distal third of the right femoral diaphysis, medullary osteolysis and interruption of the cranio-medial cortical profile, with involvement of the femoral trochlea leading to a secondary medial patella luxation. Hematogenous osteomyelitis was the suspected diagnosis. Once skeletally mature, after 4 months from surgical debridement and aggressive antibiotic therapy against Klebsiella oxytoca revealed by a bacteriological exam, the patient underwent prosthetic surgery for the application of a custom-made patellar groove replacement (PGR) to fill the bone defect and restore the femoral trochlea surface. Despite the serious injury that afflicted the right pelvic limb, the surgery had satisfactory outcomes until the last 18-month postoperative follow up.

Biomechanical effects of cranial closing wedge osteotomy on joint stability in normal canine stifles: an ex vivo study.

BACKGROUND: Cranial closing wedge osteotomy (CCWO) is a functional stabilisation technique for cranial cruciate ligament (CrCL) ruptures. This biomechanical study aimed to evaluate the influence of CCWO on the stability of the stifle joint. Eighteen Beagle stifle joints were divided into two groups: control and CCWO. The stifle joints were analyzed using a six-degree-of-freedom robotic joint biomechanical testing system. The joints were subjected to 30 N in the craniocaudal (CrCd) drawer and proximal compression tests and 1 Nm in the internal-external (IE) rotation test. Each test was performed with an extension position, 135°, and 120° of joint angle. RESULTS: The stifle joints were tested while the CrCLs were intact and then transected. In the drawer test, the CCWO procedure, CrCL transection, and stifle joint flexion increased CrCd displacement. The CCWO procedure and CrCL transection showed an interaction effect. In the compression test, the CCWO procedure decreased and CrCL transection and stifle joint flexion increased displacement. In the IE rotation test, CCWO, CrCL transection, and stifle joint flexion increased the range of motion. CONCLUSIONS: CCWO was expected to provide stability against compressive force but does not contribute to stability in the drawer or rotational tests. In the CCWO-treated stifle joint, instability during the drawer test worsened with CrCL transection. In other words, performing the CCWO procedure when the CrCL function is present is desirable for stabilizing the stifle joint.

Effect of center of rotation of angulation-based levelling osteotomy on instantaneous center of rotation ex vivo.

Cranial cruciate ligament rupture is a common cause of femorotibial instability in dogs. Despite numerous techniques being described for achieving joint stabilization, no consensus exists on the optimal management strategy. This ex vivo study utilized the path of the instantaneous center of rotation (ICR) to compare normal, pathological and treated joints. Fluoroscopic recordings of seven limbs from a previous study of canine stifle joint stability following center of rotation of angulation-based levelling osteotomy (CBLO) with and without hamstring loading were analyzed using least-squares approximation of the ICR and estimation of percentage gliding (vs. rolling) to determine if alterations in ICR path and gliding caused by CCL transection and following meniscal release could be normalized by CBLO. In intact joints, the ICR path was located mid-condyle, but this shifted significantly proximally and caudally following CCL transection and medial meniscal release (p < 0.007, p < 0.04). Hamstring loading resulted in qualitative and some quantitative improvements in joint movement based on percentage gliding movement analysis. The ICR path after CBLO remained significantly different to the intact location with or without a hamstring load (p < 0.02, p < 0.04), potentially consistent with CBLO aims of mild residual instability. CBLO resulted in percentage gliding characteristics not significantly different to intact joints (p > 0.08). Qualitative improvements in ICR path and percentage gliding quantities and variability suggest that hamstring loading positively influences joint biomechanics and that further investigation of this role ex vivo and clinically is warranted.

Muscle function assessment of the hindlimbs in healthy dogs using acoustic myography.

INTRODUCTION: Impaired muscle function is a frequent consequence of musculoskeletal disorders in dogs. Musculoskeletal disorders, especially stifle joint diseases, are common in dogs and assessment of muscle function in dogs is clinically relevant. Acoustic myography (AMG) is a non-invasive method to assess muscle activity. Quantifying muscle function in normal dogs could help identify clinically relevant changes in dogs with orthopaedic disease and allow targeted interventions to improve recovery in these. The objectives of the study were to characterize hindlimb muscle function in healthy dogs using AMG and to investigate the repeatability and reproducibility of AMG in dogs. METHODS: Healthy dogs (15-40 kg) without musculoskeletal disorders were recruited and screened for eligibility to participate in the study. The muscle activity in four hindlimb muscles related to the stifle was assessed using AMG. The degree of symmetry between the hindlimbs in these dogs was investigated and the reliability of AMG was evaluated. RESULTS AND CONCLUSIONS: The study population comprised 21 dogs. Reference intervals and symmetry indices for AMG scores of the hindlimb muscles were identified, with highest variability for the E-scores. For all AMG-scores, same-day variation was lower than between days variation, and both were lowest for S- and T-scores. Further investigation is needed to establish if AMG can enable discrimination between dogs with altered muscle function and healthy dogs.

Three-dimensional modelling and morphological investigation of the bones of the Articulatio genus using computed tomography images in Van cats.

In this study, it was aimed to make three-dimensional reconstruction of the stifle joint computed tomography (CT) images of the Van cats, to obtain their osteometric measurements, and to determine the statistical biometric differences of these measurement values in terms of both sexual dimorphism and homotypic variations. A total of 16 healthy adult Van cats of both sexes were used. The stifle joints of the cats were scanned with a CT device and images were obtained. Three-dimensional reconstructions of the bony structures of the stifle joint were performed using CT images using the MIMICS 20.1 modelling program. Then, osteometric measurements were calculated, and statistical analysis was performed. When the morphometric measurement values were examined in terms of gender, it was observed that almost all of the osteometric measurement values of the stifle joint in Van cats (except SPW measurement) were higher in male cats. According to homotypic variations, right side TPW (p = 0.009), TPCMA (p = 0.003) and TPMCA (p = 0.032) measurement values in female cats and right side TPLCA (p = 0.002) measurement values in male cats were found to be statistically significantly higher than the left side from the measurements of only the proximal tibia (p < 0.05). In general, although there were negative correlations between morphometric measurement values with age and body weight, mostly strong positive correlations were seen. As a result, statistical differences of the biometric values and anatomical features of the stifle joint between the sexes in Van cats between the sexes were examined using CT and a three-dimensional modelling program.

Establishment of an image evaluation grading criteria for experimental stifle joint osteoarthritis in dogs: an X-ray and CT imaging study.

BACKGROUND: This study aimed to establish an image evaluation grading criteria for experimental stifle joint osteoarthritis (OA) in anterior cruciate ligament transection induced OA beagle dog models. The severity of OA was assessed using X-ray and computed tomography (CT) imaging. RESULTS: A total of 32 dogs (8 controls and 24 OA-induced dogs) were included in the study. The OA-induced group showed significantly higher manual joint palpation, gait analysis, and OA severity scores than the control group. Based on these two results, we calculated correlation coefficients. There was a strong positive correlation between manual joint palpation scores and OA severity on diagnostic imaging and between gait analysis scores and OA severity. CONCLUSIONS: The developed grading criteria based on radiographic evaluation correlated with clinical assessments. The study also employed CT imaging to enhance the accuracy and sensitivity of early-stage OA change detection in the stifle joint. However, further studies with larger sample sizes and multiple evaluators are recommended for the validation and generalizability of this grading system. These established image evaluation grading criteria can help evaluate and monitor the efficacy of interventions and changes in OA lesions in canine models.

Dome trochleoplasty for correction of patella alta and patella luxation in dogs > 20 kg.

OBJECTIVE: To describe the dome trochleoplasty procedure and report the short-term outcomes and complications associated with a novel technique to correct patellar luxation and patella alta. ANIMALS: 13 dogs (16 stifle joints) diagnosed with medial patellar luxation with concurrent patella alta in dogs > 20 kg. CLINICAL PRESENTATION: Medical records of dogs weighing > 20 kg that underwent a dome trochleoplasty for correction of a medial luxating patella were prospectively evaluated. The procedure described involves an osteotomy of the femoral trochlea, which is then translated and/or rotated to correct patellar luxation. Clinical results were assessed using subjective lameness scoring, radiographic evaluation, and the Canine Brief Pain Inventory (CBPI) tool. RESULTS: 16 stifle joints were included in this study. The overall complication rate was 50%. Major complications occurred in 43.8% of stifle joints due to pin migration and recurrent luxation of the patella. One dog experienced a catastrophic complication 4 months postoperatively. Uncomplicated osteotomy healing was present in 94% of dogs. The median initial lameness score was 2 (mean, 1.81; range, 0 to 4) and at the final recheck was 0 (mean, 0.31; range, 0 to 2). The CBPI scores were available for 50% of stifle joints. The median initial CBPI score was 45.5 (mean, 48.8; range, 32 to 74) and at the final recheck was 17.5 (mean, 20.5; range, 0 to 43). CLINICAL RELEVANCE: The dome trochleoplasty procedure offers an alternative technique for surgical correction of patellar luxation secondary to patella alta in large-breed dogs, but due to its higher complication and reluxation rates, it should be used cautiously and probably in combination with other corrective procedures, such as tibial tuberosity transposition, soft tissue imbrication, and/or soft tissue release rather than as a stand-alone procedure.

Diagnostic Performance of Multi-Detector Computed Tomography Arthrography and 3-Tesla Magnetic Resonance Imaging to Diagnose Experimentally Created Articular Cartilage Lesions in Equine Cadaver Stifles.

BACKGROUND: The purpose of the study was to determine the diagnostic performance of computed tomographic arthrography (CTA) and 3-Tesla magnetic resonance imaging (MRI) for detecting artificial cartilage lesions in equine femorotibial and femoropatellar joints. METHODS: A total of 79 cartilage defects were created arthroscopically in 15 cadaver stifles from adult horses in eight different locations. In addition, 68 sites served as negative controls. MRI and CTA (80-160 mL iodinated contrast media at 87.5 mg/mL per joint) studies were obtained and evaluated by a radiologist unaware of the lesion distribution. The stifles were macroscopically evaluated, and lesion surface area, depth, and volume were determined. The sensitivity and specificity of MRI and CTA were calculated and compared between modalities. RESULTS: The sensitivity values of CTA (53%) and MRI (66%) were not significantly different (p = 0.09). However, the specificity of CTA (66%) was significantly greater compared to MRI (52%) (p = 0.04). The mean lesion surface area was 11 mm2 (range: 2-54 mm2). Greater lesion surface area resulted in greater odds of lesion detection with CTA but not with MRI. CONCLUSIONS: CTA achieved a similar diagnostic performance compared to high-field MRI in detecting small experimental cartilage lesions. Despite this, CTA showed a higher specificity than MRI, thus making CTA more accurate in diagnosing normal cartilage. Small lesion size was a discriminating factor for lesion detection. In a clinical setting, CTA may be preferred over MRI due to higher availability and easier image acquisition.

Stifle Joint Arthrodesis for Treating Chronic-Osteoarthritis-Affected Dogs.

A two-year-old male Pomeranian dog was presented to a veterinary hospital due to the side effects of a surgical correction for patellar luxation. Stifle joint arthrodesis (SJA) was performed on the patient's right leg using autologous bone-grafting techniques. The right femur and tibial joint were angled 120-130°, and an SJA plate was fixed on the front of the two bones. After performing joint fusion of the right limb, medial-patellar-luxation-(MPL)-corrective surgery was performed to cut the tibial tuberosity on the left leg, and the fixing force was increased using the figure-of-eight-tension-band-wiring technique. Results were recorded regarding the dog's ability to walk and trot in the right hind limb; these results were evaluated for 27 days after surgery. It was difficult for the patient to walk because weight-bearing had not been carried out for 3 days after the surgery; short strides and partial weight bearing were possible 5 to 7 days after surgery. After 10 days, the patient was able to move while bearing weight with a slight disruption. With regard to trotting, the patient showed intermittent normal steps 5 to 7 days after surgery, but the disruption continued. After 14 days, trotting was possible, and it was observed that movement could be maintained during everyday activities.

Morphological study of the arterial supply to the menisci in pigs with special reference to creating meniscus injury model.

BACKGROUND: Some reports have used pigs to establish models of meniscus injury. However, accurate information on the origin, course, and access of the arteries supplying the menisci remains unclear. This information is important to avoid damaging vital arteries when creating the meniscus injury model. MATERIALS AND METHODS: In this study, fetal and adult pigs were employed to investigate the arterial supply of the menisci in pigs using gross anatomical and histological methods. RESULTS: Macro-anatomically, the anterior horn, body, and posterior horn of the medial meniscus were found to be supplied by the medial superior genicular artery, medial inferior genicular artery, and posterior middle genicular artery. The anterior and posterior horns of the lateral meniscus were supplied by the cranial tibial recurrent artery and the middle genicular artery, respectively. Anastomosis was observed in some cases, but appeared to be infrequent and too thin to expect the anastomotic branches to provide adequate blood flow. The histological examination showed that the arteries entered the meniscus along the tie-fiber. The access process of the artery was the same irrespective of whether it was in fetal or mature pigs, the medial or lateral meniscus, or the anterior horn or body or posterior horn. The medial inferior genicular artery ran along the medial meniscus in the circumferential direction. Therefore, the clinical longitudinal incision should take into account the characteristics of the vessel course in order to protect the blood vessels from damage. CONCLUSIONS: Based on the results of this study, the protocol for creating a pig meniscus injury model should be reconsidered.

Postoperative efficacy of chondroprotectors and diacerein in dogs with osteoarthritis secondary to cranial cruciate ligament disease.

Background: Cranial cruciate ligament disease is one of the leading causes of pelvic limb claudication in canines and osteoarthritis in the stifle joint. Historically, studies have focused on surgical options to improve the stability of the stifle joint, although none of the techniques described in the literature prevents the development of osteoarthritis. Aim: This study aimed at proving the presence of osteoarthritis at the time of diagnosis of cranial cruciate ligament rupture, as well as evaluating the benefits of administering diacerein (DAR) or chondroprotective coadjuvants to the extracapsular fabelo-tibial technique. Methods: Seventeen dogs aged between 2 and 8, weighing more than 25 kg, with no predilection for breed or sex, were operated on using this technique. These were divided into three groups: DAR, Chondroprotector (CP), and Control. The animals were treated for 90 days and controlled clinically, radiologically, and using multidimensional scales for pain and quality of life. The statistical analysis used was descriptive and through non-parametric tests. Results: All patients had some degree of osteoarthritis at the beginning of the study associated with the presence of pain. The treated groups improved the claudication scores; however, the changes were significant for the DAR group. The pain score improved in all animals, including those in the Control group; however, the differences were significant only in the treated groups. On the other hand, no significant differences were detected in the radiological studies, so it would be convenient to perform this study over more than 90 days. Conclusion: The surgical treatment accompanied by drugs that act on the degradation of articular cartilage has better clinical results.

Comparison of Digital Radiography, Computed Tomography, and Magnetic Resonance Imaging Features in Canine Spontaneous Degenerative Stifle Joint Osteoarthritis.

Canine stifle joint osteoarthritis (OA) is characterized by damage and degeneration of the articular cartilage and subchondral bone, bony hypertrophy at the margins, and synovial joint membrane changes. Non-invasive imaging modalities, such as digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI), can be used to describe these changes. However, the value of MRI in diagnosing spontaneous canine OA and the comparison of different imaging modalities have seldom been addressed. This study compared multiple noninvasive imaging modalities in canine spontaneous stifle OA cases. Four client-owned dogs with five spontaneously affected OA stifle joints were recruited and underwent DR, CT, and MRI. Information on osteophytes/enthesophytes, ligament/tendon lesions, synovial effusion and membrane thickening, subchondral bone lesions, and meniscal and cartilage lesions were scored and compared. The results showed that MRI provides the most comprehensive and superior lesion detection sensitivity for ligament, meniscus, cartilage, and synovial effusions. DR provides adequate bony structure information, while CT provides the most delicate images of bony structure lesions. These imaging findings may provide further understanding of the disease and help clinicians draft a more precise treatment plan.

Deep learning-based diagnosis of stifle joint diseases in dogs.

In this retrospective, analytical study, we developed a deep learning-based diagnostic model that can be applied to canine stifle joint diseases and compared its accuracy with that achieved by veterinarians to verify its potential as a reliable diagnostic method. A total of 2382 radiographs of the canine stifle joint from cooperative animal hospitals were included in a dataset. Stifle joint regions were extracted from the original images using the faster region-based convolutional neural network (R-CNN) model, and the object detection accuracy was evaluated. Four radiographic findings: patellar deviation, drawer sign, osteophyte formation, and joint effusion, were observed in the stifle joint and used to train a residual network (ResNet) classification model. Implant and growth plate groups were analyzed to compare the classification accuracy against the total dataset. All deep learning-based classification models achieved target accuracies exceeding 80%, which is comparable to or slightly less than those achieved by veterinarians. However, in the case of drawer signs, further research is necessary to improve the low sensitivity of the model. When the implant group was excluded, the classification accuracy significantly improved, indicating that the implant acted as a distraction. These results indicate that deep learning-based diagnoses can be expected to become useful diagnostic models in veterinary medicine.

Ex Vivo Comparison of the Diagnostic Performance of Two-Dimensional and Three-Dimensional Three-Tesla Magnetic Resonance Imaging Sequences in Depicting Normal Articular Cartilage in Equine Stifle Cadavers.

The objective of this study was to compare articular cartilage thickness observed in the different 2D and 3D sequences to the cartilage thickness of the equine stifle in cadavers to determine the accuracy of each sequence. The study was conducted as a blinded laboratory study using seven equine stifle specimens. The 2D (T2W TSE) and 3D (3D VIEW T2W HR, T2 3D mFFE, T1W VISTA SPAIR, 3D PDW SPAIR) 3-tesla MRI sequences of each stifle were obtained. Cartilage thickness was measured at 30 locations on MRI and on gross pathology. Thickness measurements were compared using a Bland-Altman plot and post hoc analysis tests. The 3D sequences were found to be generally more accurate than the 2D sequence (p < 0.001). The smallest difference to macroscopic measurements was observed in the 3D VIEW T2W HR and T1W VISTA SPAIR sequences with no statistical difference between each other. Knowing the accuracy of different sequences will improve the evaluation of equine cartilage and the early detection of cartilage pathologies. This would promote MRI as a noninvasive imaging modality for horses suffering from stifle lameness with no findings in conventional imaging methods. Furthermore, since 3D sequences seem to have better accuracy in depicting cartilage, they may replace 2D sequences, thereby shortening scanning times.

Intra-articular osteoma in the stifle joint of a cat.

Case summary: A 13-year-old male castrated cat was referred to our clinic for a 2-month history of right hindlimb lameness. Radiographs and CT showed a solid bony mass within the stifle joint. The mass was resected by arthrotomy and osteotomy of the tibial tuberosity. Histopathological examination revealed the diagnosis of osteoma. Recovery from surgery was uneventful. At the 8-week follow-up examination, the cat was free of clinical signs. Relevance and novel information: Feline osteomas are rare; only few cases have been reported. To the best of our knowledge, this is the first report of an intra-articular osteoma in the stifle joint of a cat and description of its surgical resection.

Modified Tibial Tuberosity Advancement Rapid in a Dog with One Contralateral Amputated Limb.

Cranial cruciate ligament disease (CCLD) is one of the most frequent causes of hindlimb lameness in dogs. Tibial tuberosity advancement (TTA) is a common surgery performed for CCLD. A modified, simplified technique (TTA Rapid) is also reported to have very good clinical outcomes. In this paper, we report a modified TTA Rapid technique to treat a CCLD in a dog with an amputated contralateral hindlimb. A 5-year-old mixed breed dog presented with amputated right hindlimb and difficulty walking. Pain and positive drawer sign were present at manipulation of left stifle joint. Radiographic findings of the stifle joint confirmed the presence of moderate osteoarthritis associated with CCLD, and modified TTA Rapid procedure was performed. Recovery from surgery was uneventful, and the dog was able to stand by his own by the second day postoperative. At three months follow-up evaluation, the dog was free of lameness and the osteotomy site was completely healed. This paper describes the first modified TTA rapid osteotomy technique performed in a dog with a contralateral amputated hindlimb.

Morphometric assessment of the medial collateral ligament of the canine stifle joint.

OBJECTIVE: The study provides a morphometric assessment of the medial collateral ligament (MCL) of the canine stifle joint. STUDY DESIGN: Eighty-six stifle joints were collected from 43 canine cadavers and dissected to free them of soft tissue and expose the collateral ligaments. The MCL insertion sites were identified with Chinese ink on intact stifle joints and also marked with radiopaque paste after removal of the MCL. Mediolateral photographs and radiographs of each stifle joint were taken after MCL was removed for morphometric assessment. Measurements were taken in two groups: a group of Beagles (group 1), and a group composed of different breeds (group 2). RESULTS: In all stifle joints, the MCL had an hourglass shape. It inserted in the distal femur and the proximal tibia, and was also intimately attached to the medial meniscus and more loosely to the proximal tibial epiphysis in its central portion. The MCL tibial insertion (TI) site had the largest surface area. Its proximal and distal position relative to the tibial plateau was located at 8.24 ± 1.17% and 15.54 ± 1.50% respectively of the total tibial length in group 1, and at 8.86 ± 1.93% and 15.53 ± 2.11% respectively, of the total tibial length in group 2. These values were not statistically different. CONCLUSION: The MCL of the canine stifle joint has an insertion site on the femur and on the tibia and is also attached on the medial meniscus. The location of the MCL TI site seems to be relatively homogeneous in dogs.

Effects of Internal Fluid Pressure on Stresses in Subchondral Bone Cysts of the Medial Femoral Condyle.

The etiology of subchondral bone cysts (SBCs) is not fully understood. Mechanical trauma and fluid pressure are two mechanisms believed to cause their formation and growth. The equine stifle joint provides a natural animal model for studying SBCs. Computed tomography images of an extended yearling cadaveric stifle joint were segmented using ScanIP to isolate bones and relevant soft tissues. Three model geometries were created to simulate cyst sizes of approximately 0.03 cm3 (C1), 0.5 cm3 (C2), and 1 cm3 (C3). A uniform pressure resulting in 3000 N force was applied at the proximal end of the femur. Two types of simulations, filled-cyst and empty-cysts with uniform pressure loads, were used to simulate fluid pressurization. Our models suggest that shear stresses are likely the cause of failure for the subchondral bone and not pressurized fluid from the joint. Bone stresses did not begin to increase until cyst pressures were greater than 3 MPa. For all cyst sizes, fluid pressure must rise above what is likely to occur in vivo in order to increase bone shear stress, shown to be most critical. Synovial fluid pressure acts upon a porous trabecular bone network, soft tissue, and marrow, so the continuum nature of our model likely overestimates the predicted effects of fluid pressures.

Assessment of the Usefulness of Image Reconstruction in the Oblique and Double-oblique Sagittal Planes for Magnetic Resonance Imaging of the Canine Cranial Cruciate Ligament.

INTRODUCTION: The aim of the study was to determine the quality and significance of the magnetic resonance image of the canine knee after reconstruction in the oblique and double-oblique sagittal plane. This reconstruction and 3D images are rarely used in common protocols due to the longer study time they require. The study aimed to demonstrate significance for such diagnostic images in specific sequences in order to stimulate consideration of their more frequent use in diagnosis of diseases of the cruciate ligament in dogs. MATERIAL AND METHODS: All tests were carried out using an open magnetic resonance tomography scanner with magnetic field induction. The images obtained from the 30 canine patients examined were reconstructed and evaluated by independent appraisers. Statistical analysis was performed. RESULTS: The study showed that MRI of the stifle joint using 3D sequences provides higher quality images of the cranial cruciate ligament in dogs. The results of the statistical analysis showed that multi-faceted reconstruction allows the secondary determination of the oblique imaging planes and obtains images of adequate quality. CONCLUSION: It can be concluded that multi-faceted reconstruction facilitates the secondary determination of oblique imaging planes. This reconstruction additionally makes images available of better quality compared to the 2D sequence.

Treatment of cranial cruciate ligament injuries in dogs using a combination of tibial tuberosity advancement procedure and autologous mesenchymal stem cells/multipotent mesenchymal stromal cells - A pilot study.

In the present pilot study, we evaluated different supplemental therapies using autologous multipotent mesenchymal stromal cells (MMSCs) for the treatment of cranial cruciate ligament defects in dogs. We used tibial tuberosity advancement (TTA) and augmented it by supportive therapy with MMSCs in three patient groups. In the first patient group, the dogs were injected with MMSCs directly into the treated stifle one month after surgery. In the second group, MMSCs were delivered in a silk fibroin scaffold which was placed in the osteotomy gap during surgery. In the third group, MMSCs were first mixed with bone tissue and blood from the patient and delivered into the osteotomy gap during surgery. In the control group, patients underwent the TTA procedure but did not receive MMSC treatment. In the group of patients who received cells in the silk fibroin scaffold during surgery, the osteotomy gap did not heal, presumably due to the low absorption of silk fibroin. Patients who received MMSCs mixed with bone tissue and blood during surgery into the osteotomy gap recovered clinically faster and had better healing of the osteotomy gap than dogs from the other two treated groups and from the control group, as assessed by clinical examination and quantification of radiographs. In conclusion, dogs that received stem cells directly into the osteotomy gap (Group 3) recovered faster compared to dogs from Groups 1 (MMSCs injected into the joint one month after surgery), 2 (cells implanted into the osteotomy gap in a silk fibroin scaffold), and the control group that did not receive additional MMSCs treatment.