Patellar luxation in dogs

Biomechanical evaluation of a fixation technique with a modified hemicerclage for tibial tuberosity transposition: an ex vivo cadaveric study

Objectives

(1) To determine stiffness, load at failure, and mode of failure of a novel fixation method with a tension modified-hemicerclage (MH) for tibial tuberosity transposition, and (2) to compare the biomechanical properties of this novel fixation technique to 2 pins (2Pins) and 2 pins and tension band wire fixation (2Pins + TBW).

Study design

Thirty cadaveric stifles from dogs between 5.2 and 13.1 kg were assigned to 3 treatment groups: Group 1: fixation technique with MH; Group 2: 2Pins; Group 3: 2Pins + TBW. Biomechanical testing was performed with the tibia positioned at an angle of 135° relative to vertical position. Tensile force was applied to the patellar ligament until catastrophic failure was observed. The mode of failure, the load at failure, and the stiffness were compared among treatment groups.

Results

The mean stiffness of the novel fixation (38.1 N/mm ± 7.1) and the 2Pins + TBW (40.2 N/mm ± 9.3) were greater than the 2Pins (26.7 N/mm ± 6.7). There was no significant difference between the novel fixation technique and 2Pins + TBW in stiffness and maximum load to failure. The 2Pins (284.3 N ± 70.5) failed at a significantly lower load than the tension modified-hemicerclage (555.7 N ± 225.9 N) and 2Pins + TBW (715.3 N ± 339.8 N).

Conclusion

A fixation technique using a modified hemicerclage had the same strength and stiffness as the 2Pins + TBW and was stronger and stiffer than the 2 Pins technique in a cadaveric model.

3D Slicer open-source software plug-in for vector-based angle calculation of canine hind limb alignment in computed tomographic images

BACKGROUND

Severe and complex angular limb deformities in dogs require accurate morphological assessment using diagnostic imaging to achieve successful orthopedic surgery. Computed tomography (CT) is commonly used to overcome projection errors in two-dimensional angular measurements of dog hindlimb alignment. Three-dimensional volume rendering (VR) techniques permit virtual positioning and variable projection, but the final CT-image that defines the projection plane for angular measurements remains two-dimensional.

OBJECTIVE

We wanted to develop a true three-dimensional open-source technique to measure the alignments of the hind limbs of dogs in CT scanners.

METHODS

We developed an open-source 3D Slicer plug-in, to perform angular measurements using vector calculations in three-dimensional space. In 113 CT-scans of canine pelvic limbs, femoral torsion, femoral varus, femorotibial rotation, tibial torsion, tibial varus and tibiotalar rotation angles were calculated and compared to an already validated technique using VoXim®.

RESULTS

Reference points were identified and measurements were possible in the 113 acquisitions. The greatest difference between the two techniques was 1.4° at only one tibial torsion angle. Mean values for all Bland-Altman plots did not show significant differences and were less than 0.07° for all comparisons.

DISCUSSION

Based on these results we considered angular measurements of canine hind limb alignment in CT scans using the 3D Slicer extension program sufficiently accurate for clinical orthopedic and surgical purposes in veterinary medicine.

CONCLUSION

With our open-source 3D Slicer extension software, we provide a free accessible tool for veterinary orthopedic surgeons and thus we hope to improve angular measurements in CT-scans of canine hind limb deformities through true three-dimensionality.

Comparative analysis of post-operative rehabilitation approaches for medial patellar luxation in small-breed dogs

Background and Aim

Electrical stimulation (ES) and light amplification by stimulated emission of radiation (LASER) therapy are frequently used in post-operative rehabilitation; however, there is currently insufficient research comparing their effectiveness. This study aimed to assess the effectiveness of post-operative rehabilitation following medial patellar luxation (MPL) surgical correction by comparing ES and LASER therapy when combined with exercise. This was compared with a control group that consisted solely of post-operative home exercise implemented by the owner.

Materials and Methods

We conducted a prospective clinical trial on dogs that had undergone surgical treatment for MPL. The dogs were categorized into the following three groups: The control group, which did not participate in any post-operative rehabilitation program; the ES group, which received post-operative rehabilitation involving ES therapy; and the LASER group, which underwent post-operative rehabilitation featuring LASER therapy.

Results

There were no significant differences among the groups regarding the evaluation parameters, including lameness score, pain score, thigh muscle circumference, and range of motion. Although there may have been a difference in pain score in some groups, it could be attributed to the pre-operative condition of patients. These results aligned with the owner questionnaires' canine brief pain inventory assessments, showing no significant differences between treatment groups.

Conclusion

Post-operative rehabilitation for MPL correction may enhance limb usage, joint function, muscle mass, and pain relief. However, the duration and level of post-operative pain may influence the necessity for rehabilitation. In addition, ES and LASER therapy offer similar pain-relieving effects after MPL surgery; therefore, the choice between these methods depends on the availability of equipment and veterinarian preferences.

Detecting medial patellar luxation with ensemble deep convolutional neural network based on a single rear view image of the hindlimb

Medial patellar luxation (MPL) is a common orthopedic disease in dogs, which predisposes elderly and small-breed dogs. Unlike in humans, diagnosis in the early course of the disease is challenging because symptoms and joint-pain expression in canines are vague. Herein, we introduced a deep-learning system to diagnose MPL using a single rear-view hindlimb image. We believe that this is the first attempt to build a deep-learning system to diagnose MPL based on image analysis. Notably, 7689 images were collected from 2653 dogs in 30 private animal clinics between July 2021 and July 2022. Model performance was compared with ResNet50, VGG16, VGG19, Inception-V3, and veterinarian performance. For performance comparison, a professional veterinarian with > 10 years of experience selected images of 25 normal dogs and 25 dogs with MPL. The proposed model showed the highest performance, with 92.5% accuracy, whereas human experts showed an average accuracy of 55.2%. Therefore, our model can diagnose MPL using only a single rear-view hindlimb image. Furthermore, to solve the image uncertainty caused by the input image noise, we used a one-class SVM and ensemble learning methods to ensure model robustness. Our study will help diagnose MPL in clinical settings using a single rear-view hindlimb image.

Bacterial DNA and osteoarthritis in dogs with patellar luxation and cranial cruciate ligament rupture

Background and Aim

The association between bacterial DNA in stifle joints, including those with cranial cruciate ligament rupture (CCLR) and medial patellar luxation (MPL), and osteoarthritis in dogs remains elusive. This study investigated the potential association between the detection of bacterial DNA and osteoarthritis in dogs using a broad-range polymerase chain reaction technique targeting the 16S ribosomal RNA gene.

Materials and Methods

Synovial fluid (35 samples) and knee tissue samples (32 samples) were obtained from 35 dogs diagnosed with CCLR (n = 20; 11 males and nine females) or MPL (n = 15; five males and 10 females) who underwent a surgical operation between October 2014 and April 2015.

Results

Dogs with CCLR had a higher average osteoarthritis score than those with MPL (2.0 ± 0.9 vs. 0.5 ± 0.9; p = 0.005). Bacterial DNA was detected in the stifle joints of 60.71% of dogs with MPL. Pelomonas spp. (25.00%), Halomonas spp. (17.86%), and 5 other species (17.86%) were the most frequently identified bacteria. Bacterial DNA was detected in 41.03% of dogs with CCLR. Pelomonas spp. (15.38%), Sphingomonas spp. (10.26%), Halomonas spp. (5.13%), and 4 other species (10.26%) were the most frequently identified bacteria. No significant difference was observed in the prevalence of bacterial DNA obtained from tissue samples (46.88%) or joint fluid samples (51.43%). The presence of bacterial DNA was not associated with the type of knee injury (MPL or CCLR; p = 1.000). There was a higher prevalence of bacterial DNA in samples from dogs with moderate-to-severe osteoarthritis (94.44%) than in those with minimal osteoarthritis (41.18%), and a significant association between the presence of bacterial DNA and moderate-to-severe osteoarthritis was identified (p < 0.01).

Conclusion

Dogs with moderate-to-severe osteoarthritis were more likely to have bacterial DNA in their stifle joints than those with no or minimal osteoarthritis. These findings provide valuable insight into the potential role of bacterial DNA in joint tissue or joint fluid and the development of osteoarthritis in dogs.

Comparison of CT-measured angles of pelvic limbs without patellar luxation of six canine breeds

Introduction

Dogs with medial patellar luxation can be affected by pelvic limb deformities whose corrective osteotomies and associated biomechanical rebalancing might provide higher success rates than standard surgical procedures limited to the stifle joint. In bilaterally affected canine patients, comparison with the contralateral normal limb is impossible. Reference values are useful for orthopedic decision-making. Inconsistency of published reference values might depend on methodology or canine breed. We hypothesized that canine pelvic limb alignment is breed-specific.

Methods

CT scans of 42 pelvic limbs of dog breeds predisposed for medial patellar luxation, with an orthotopic patellar position and stability were studied. Several angleswere measured with an open-source 3D Slicer plugin using vector calculations. The breeds were compared with a general linear model with a Bonferonni adjustment using SPSS.

Results

Chihuahuas, Pomeranians, Jack Russel Terriers, Pugs, French Bulldogs, Maltese were examined. In the order of the listed breeds, the angles were as follows: 28.3°±10.7°, 20.1°±2.9°, 35.4°±6.9°, 32.8°±3.0°, 19.0°±7.1°, 26.6°±5.3° for the antetorsion, 5.3°±1.8°, 2.8°±2.8°, 8°±4.4°, 3.8 °±3.1°, 4.7°±3.3°, 2.3°±3.3° for the femoral varus, of -5.5°±6.2°, 1.1°±4.1°, -5.2°±9.5°, 6.1°±8.0°, -0.1°±5.9°, -9.2°±4.7° for the tibial torsion, 2.0°±2.9°, 2.1°±2.7°, 6.4°±6.8°, 0.0°±5.7°, 3.0°±5.8°, 8.8°±8.6° for the tibial valgus, 1.2°±10.4°, 1.8°±3.4°, -1.7°±4.9°, -1.7°±9.4°, 5.1°±8.8°, -0.2°±8.6° for the femorotibial rotation and -3.4°±2.2°, 1.1°±4.1°, -2.8°±3.4°, -5.2°±4.0°, -2.1°±4.4°, -5.4°±3.7° for the tibiotalar rotation. There were significant differences between breeds in femoral torsion, femoral varus, and tibial torsion angles, but no significant differences in tibial valgus, femorotibial, and tibiotalar rotation angles.

Discussion

Our hypothesis is therefore partially correct. Our results are limited to small dogs prone to medial patellar luxation and might not be generalized. To establish robust reference values larger case numbers and more breeds should be evaluated. In conclusion, canine pelvic limb alignment reference values for small dogs with a predisposition for medial patellar luxation should be considered breed-specific.

Acetabular rim extension using a personalized titanium implant for treatment of hip dysplasia in dogs: short-term results

Hip dysplasia (HD) is a common orthopedic problem in young dogs. To decrease the laxity of the hip joint related to HD, the surgical treatments are recommended to increase femoral head coverage. ACEtabular rim eXtension (ACE-X) using a personalized 3-dimensional printed titanium shelf implant is a new surgical treatment to increase femoral head coverage and decrease laxity of the dysplastic hip joint, however, the efficacy is less know. Client-owned dogs older than 6 months with clinical signs of coxofemoral joint subluxation and radiographic evidence of HD with no or mild osteoarthritis (OA) were included. The Norberg angle (NA), linear percentage of femoral head overlap (LFO), and percentage of femoral head coverage (PC) were investigated radiographically and with computed tomography (CT) before and after surgery. OA was graded (scores 0-3) according to the maximum osteophyte size measured on CT. In addition, joint laxity (Ortolani) test results, gait analysis, and the Helsinki chronic pain index (HCPI) questionnaire were obtained at preoperative, immediately postoperative and at 1.5- and 3-month evaluations. Acetabular rim extension was performed in 61 hips of 34 dogs; NA, LFO, and PC were significantly higher immediately postoperatively and at the 1.5- and 3-month follow-up examinations compared with preoperative values (p < 0.05). Osteophyte size gradually increased over time (p < 0.05). The OA score significantly increased between preoperatively and directly postoperatively, and between preoperatively and at 3-month follow-up (p < 0.05). The laxity test normalized in 59 out of 61 hips after surgery, and the HCPI questionnaire showed that the pain score decreased significantly at 1.5 and 3 months, postoperatively. The force plate showed no significant improvement during the 3 months follow-up. Although pain reduction by the implant was unclear in short-term results, a personalized shelf implant significantly increased femoral head coverage and eliminated subluxation of the dysplastic hip joint. Further studies are required to study the long-term efficacy of gait, chronic pain, and progression of osteoarthritis.

Prevalence of Dental and Skeletal Malocclusions in Mesaticephalic and Dolichocephalic Dogs—a Retrospective Study (2015–2018)

Medical records of dogs with dolico- or mesaticephalic conformation who were presented to a private veterinary referral dental practice with malocclusion of the deciduous or permanent dentition were retrospectively reviewed from a 3-year period (2015–2018). Records were evaluated to determine the type(s) of malocclusions and 198 dogs were evaluated with permanent malocclusions. Of the dogs with deciduous malocclusions, 45 (60%) had variations of a MAL1, 28 (38%) had a MAL2, 13 (17.6%) had a MAL3, and four (5.4%) had a MAL4, with 19 (26%) having more than one type of malocclusion. Poodles, Labrador Retrievers, and Cavalier King Charles Spaniels consisted of 37 (50%) of the dogs with deciduous malocclusions. Fifty-five (74%) dogs proceeded with interceptive orthodontics. Of the dogs with permanent malocclusions, 128 (65%) had a variant of a MAL1, 60 (30%) had a MAL2, 75 (38%) had a MAL3, and 11 (5.6%) had a MAL4, with a MAL1 occurring concurrently with 49 (82%) MAL2 cases. The most common type of MAL1 was linguoversion of one or both mandibular canine teeth in 92 (72%) dogs. The five most commonly affected breeds with permanent malocclusions were Poodles, Labrador Retrievers, Chihuahuas, Pit Bull Terriers, and Cavalier King Charles Spaniels. Overall, 39 (18%) dogs presented with malocclusions observed in this study were associated with the Poodle breed and 20 (9%) dogs were associated with the Labrador Retriever breed. This trend among Poodle mixes and Labrador Retrievers supports a familial pattern to malocclusions.

Navigating regulatory pathways for translation of biologic cartilage repair products

Long-term clinical repair of articular cartilage remains elusive despite advances in cartilage tissue engineering. Only one cartilage repair therapy classified as a "cellular and gene therapy product" has obtained Food and Drug Administration (FDA) approval within the past decade although more than 200 large animal cartilage repair studies were published. Here, we identify the challenges impeding translation of strategies and technologies for cell-based cartilage repair, such as the disconnect between university funding and regulatory requirements. Understanding the barriers to translation and developing solutions to address them will be critical for advancing cell therapy products for cartilage repair to clinical use.

Patellar luxation and concomitant cranial cruciate ligament rupture in dogs - A review

A patellar luxation and concomitant cranial cruciate ligament rupture is a common pathology in dogs. Diagnosis is based on clinical evidence of a patellar luxation and stifle joint instability. However, diagnostic imaging is required to assess the number of skeletal deformities and signs of instability. Surgical options include both soft tissue and osseous techniques, although, in most cases, a combination of multiple procedures is necessary to correct the patellar luxation and restore the stifle joint stability. Complication rates are generally low, but can include reluxation and implant-associated complications. This article describes the patellar luxation and cranial cruciate ligament rupture signs in dogs, including the clinical presentation and diagnosis, and discusses current treatment options.

Patellar luxation in Hejazi goats

Background

Patellar luxation (PL) is a common orthopedic affection among farm and pet animals with mostly congenital (environmental and/or genetic) background.

Aim

We report here the first observation of lateral PL in Hejazi goats bred in Libya.

Methods

Five Hejazi goats aged between 4 months and 2 years with severe hind limb lameness were admitted to Al-Sorouh veterinary clinic in Tripoli during the period from 2016 to 2018. The goats were thoroughly examined clinically and radiographically. Two goats were surgically treated, and the other three cases were not because of either the cost limitation or expected poor prognosis. The surgical intervention involved femoral trochlear sulcoplasty, medial joint capsule imbrication, and tibial tuberosity transposition.

Results

The clinical examination showed grade III-IV lateral PL. Radiologically, there were unilateral or bilateral, ventrocaudal, and dorsal PLs. Two cases were referred to surgical correction. One case almost restored the normal movement of stifle joint together with a good general status 1 year postsurgery. However, the surgical treatment was not effective in correcting the luxated patella in the second case.

Conclusion

Lateral PL is common among orthopedic affections in Hejazi goats in Libya, and its surgical treatment provided a quite convenient approach. An association between inbreeding and the PL was suggested in those cases.

Case Report: Trochlear Wedge Sulcoplasty, Tibial Tuberosity Transposition, and Lateral Imbrication for Correction of a Traumatic Patellar Luxation in a Miniature Companion Pig: A Case Report and Visual Description

The objective of this case report was to describe successful surgical and post-operative management of a medial patellar luxation in a Vietnamese Potbellied Pig. A two-year old, castrated, Vietnamese Potbellied Pig presented to a veterinary teaching hospital for right pelvic limb lameness of 2 weeks duration. Upon physical examination a grade 3 patellar luxation was diagnosed on the right pelvic limb. Surgical repair included a trochlear wedge sulcoplasty, tibial tuberosity transposition, and lateral imbrication as described for canine patellar luxation. The pig was managed post-operatively with meloxicam and a physical therapy regimen of seven weeks duration. At recheck examination the pig was sound, no complications were observed, and the owners were satisfied with the outcome. As miniature companion pigs, such as Vietnamese Potbellied Pigs are currently increasing in popularity as pets, this case demonstrated that comparative techniques from other veterinary species should be considered when considering a treatment plan for a pig with a medial patellar luxation.

Patellofemoral contact mechanics after transposition of tibial tuberosity in dogs

Background

Tibial tuberosity transposition (TTT) causes caudalization of the patellar ligament insertion in canine medial patellar luxation, which can lead to increases in patellofemoral contact pressure.

Objectives

The purpose of this study is to confirm the effect of patellofemoral contact mechanics after craniolateral and caudolateral transposition of tibial tuberosity in normal canine hindlimbs.

Methods

Craniolateral and caudolateral transposition of tibial tuberosity was performed in 5 specimens, respectively. The pressure was measured in the specimen before TTT, and then in the same specimen after TTT. In this process, data was obtained in 10 specimens. The measurement results were output as visualization data through the manufacturer's software and numerical data through spreadsheet. Based on these 2 data and the anatomical structure of the patellofemoral joint (PFJ) surface, whole measurement area was analysed by dividing into medial, lateral and central area.

Results

In craniolateralization of tibial tuberosity, total, medial, central contact pressure was decreased and lateral contact pressure was not statistically changed lateral contact pressure than normal PFJ. In caudolateralization of tibial tuberosity, total, lateral contact pressure was increased and medial contact pressure was not statistically changed than normal PFJ. Although not statistically significant changed, central contact pressure in caudolateralization of tibial tuberosity was increased in all 5 specimens.

Conclusions

These results imply that traditional TTT, prone to caudal shift of patellar tendon, can increase retropatellar pressure may lead to various complications and diseases of the stifle joint.

Effects of quadriceps angle on patellofemoral contact pressure

BACKGROUND

An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint.

OBJECTIVES

The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs.

METHODS

Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared.

RESULTS

Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P ≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001).

CONCLUSIONS

Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided.

Characterization of C-reactive protein in dogs undergoing medial patellar luxation surgery

C-reactive protein (CRP) is a major acute phase protein used to monitor response to treatment during surgical recovery. Depending on the anatomical problem, surgery type and technique, the level of CRP can change drastically. The aim of this study was to describe the changes in CRP and white blood cell (WBC) levels following surgery for medial patellar luxation in otherwise healthy dogs. Twenty-two dogs completed the study. CRP was measured using a commercially available dry chemistry slide on a commercially available in-clinic analyser. Analyses were performed using the Wilcoxon Rank Sum test and a mixed effects Poisson regression model. A significant change in CRP levels was found between the pre-anesthetic and 24 hr post-surgical timepoint with a median difference of 92.0 mg/dL (P < 0.001). Though a median drop in the CRP value of 13.9 mg/dL was observed between the 24 hr and 48 hr post-surgical time period, the result was not statistically significant (P = 0.456). Similarly, there was a significant increase in WBC between the pre-anesthetic and 24-hr post-surgical time point (P < 0.001) followed by a significant decrease in WBC between the 24 hr and 48-hr post-surgical time points (P = 0.015). In this study population, CRP levels were observed to aid in monitoring of the overall health of the dogs following surgery for medial patellar luxation. The results of this study suggest that both CRP and WBC values significantly increase by 24 hr but where CRP levels remain elevated through 48 hr post-surgery, WBC showed a significant drop between 24 and 48 hr. Further investigation into the length of time for both CRP and WBC to reach basal levels in this particular type of surgery would be of value to monitor recovery from surgery.

Evidence of genetic contribution to patellar luxation in Toy Poodle puppies

Patellar luxation (PL) is one of the most common orthopedic disorders in dogs and a genetic factor is considered to play an important role in the development of PL. Genomic analysis has attempted to identify the genetic markers associated with the development of PL but only suggestive markers have been identified. Carefully selecting breeds with higher incidence rates of congenital PL as well as affected dogs with more severe symptoms are required, but such information remains limited to date. This study aimed to assess the genetic contribution to the development of PL in puppies. Using data on PL from 2,048 puppies of the nine common breeds in Japan, the association of PL grades between the limbs, breed, and sex as well as the concordance of PL between littermates were examined. A significant correlation was found between right and left limbs in PL grades in all the puppies (Spearman rank correlation coefficient (r_s)=0.91, P<0.001) and for each breed (r_s=0.81–0.93, P<0.001). In total, 20.3% of the puppies were affected. The inter-breed difference in PL prevalence was 2.1–38.1%, and Toy Poodles showed the highest prevalence rates. Littermates of the affected puppies with PL grade ≥2 had a 16.2-fold higher risk (P<0.001). Thus, these results suggest that PL in puppies is primarily influenced by genetics, especially in Toy Poodles. These data highlight the necessity of using a breeding scheme to decrease the prevalence of PL.