Comparison of trochlear block recession and trochlear wedge recession for canine patellar luxation using a cadaver model

Outcome of surgical correction of medial patellar luxation in dogs weighing less than 10 kg

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.

Trochlear Ridge Prostheses for Reshaping Femoral Trochlear Ridges in Dogs with Patellar Luxation

OBJECTIVES

 To describe the implant characteristics and surgical application of a custom-made trochlear ridge prosthesis (TRP) and to report clinical outcomes in dogs affected by patellar luxation treated with TRP.

STUDY DESIGN

 Dogs affected by patellar luxation underwent computed tomography. A specific canine bone anatomical replica, a cutting guide, and a TRP were designed and provided for surgery. Surgical records, clinical and radiographic reassessments, complications, pre- and postoperative lameness, type and degree of patellar luxation, and TRP and patellar position after surgery were reviewed. Clinical outcomes were defined as full, acceptable, or unacceptable function.

RESULTS

 The TRP was implanted in 60 femoral trochleae: 48 unilateral and 12 bilateral. Successful correction of patellar luxation was achieved in 59/60 cases. TRP was applied with other surgical techniques in 36/60 of the cases and as the only surgical procedure in 24/60 cases. Overall, three complications were observed: two minor and one major (patellar luxation recurrence). Neither implant loosening nor infection was observed. The mean radiographic follow-up was 3.8 months. At the time of the final follow-up, 57/60 cases were scored as fully functional.

CONCLUSION

 The TRP application either alone or in combination with other surgical techniques allowed for correction of patellar luxation and improvement in preoperative lameness with nominal complications. TRP could represent a potentially reliable alternative to trochleoplasty.

Measurement of Femoral Trochlear Morphology in Dogs Using Ultrasonography

OBJECTIVE

 The aim of this study was to examine a method for measuring femoral trochlear morphology in dogs using ultrasonography, and survey femoral trochlear morphology in skeletally normal dogs.

STUDY DESIGN

 To examine the validity of ultrasonography, three raters measured the sulcus angle (SA; the angle between the medial and lateral facets) five times in five skeletally normal dogs. Intra- and interrater reliabilities were then calculated. We also calculated the correlation coefficient between SAs measured using ultrasonography and computed tomography (CT) or magnetic resonance imaging (MRI). Then, we surveyed the femoral trochlear morphology in skeletally normal dogs using ultrasonography.

RESULTS

 The intra- and interrater reliability for SAs measured using ultrasonography was good, and the correlation coefficient between SAs measured using ultrasonography and CT, or MRI, was strong. In skeletally normal dogs, the SAs for osseous contours decreased until 6 months of age. However, the SAs for cartilaginous contours did not change during the growth period.

CONCLUSION

 The ultrasonographic measurement method is reliable for the evaluation of femoral trochlear morphology in dogs. The contour of the articular cartilage surface of the femoral trochlea is already determined early in life, and ossification of the articular cartilage of the femoral trochlea proceeds until 6 months of age. The results of this study will provide crucial information for the evaluation of femoral trochlear morphology in dogs.

Partial Parasagittal Patellectomy in Dogs: A Retrospective Case Series of 19 Dogs

OBJECTIVE

 The aim of this study was to describe partial parasagittal patellectomy for the surgical management of patellar luxation, including surgical technique, proposed indications, complications, and outcomes in a cohort of dogs.

STUDY DESIGN

 This is a single-center retrospective clinical case series.

METHODS

 Medical records (2019-2020) of dogs presenting for patellar luxation were reviewed. Clinical signs, luxation direction and grade, preoperative imaging and intraoperative findings, and complications were retrospectively retrieved. Owners were contacted via questionnaire for medium- and long-term follow-up.

RESULTS

 A total of 24 stifles in 19 dogs met the inclusion criteria. Intraoperative minor complications occurred in four stifles. A single minor complication occurred postoperatively with no major complications. Increased thickness and radiographic attenuation of the patellar ligament were noted in 14 stifles at radiographic reassessment. Re-luxation was not encountered, with long-term owner-assessed outcome as good to excellent in all cases.

CONCLUSION

 Partial parasagittal patellectomy, used in conjunction with block recession trochleoplasty and tibial tuberosity transposition, provided reliable resolution of patellar luxation in canine stifles with grade 2 or 3 luxation where width mismatch between the patella and the trochlea was noted intraoperatively. Long-term outcome appears to be good to excellent with a low rate of complication.

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.

Comparison of patellofemoral contact pressure after semi-cylindrical recession trochleoplasty and trochlear block recession in feline cadavers

Introduction

The purpose of this study was to compare the changes in the patellofemoral joint (PFJ) contact mechanisms of the normal state, trochlear hypoplasia model and after performing trochleoplasty on the hypoplasia model in feline cadavers.

Methods

Twenty normal pelvic limbs were acquired from the 10 feline cadavers. First, the PFJ contact mechanisms were measured in normal state, then trochlear hypoplasia models were created using customized trochlear ridge cutting guides. After measuring PFJ contact mechanisms in the trochlear hypoplasia models, they were divided into two groups and performed semi-cylindrical recession trochleoplasty (SCRT) and trochlear block recession (TBR) were performed, respectively. After that, the PFJ contact mechanisms were measured and the values of the 4 groups (normal state, trochlear hypoplasia, SCRT, TBR) were compared.

Results

The trochlear hypoplasia group showed increased contact pressure and decreased contact areas compared to the normal state group. In the groups that underwent tracheoplasty (SCRT and TBR), PFJ contact mechanisms were recovered similarly to that of the normal state group. The PFJ of the SCRP group was measured similar to that of the normal group than that of the TBR group.

Discussion

Tracheoplasty can be useful in restoring PFJ contact mechanisms and SCRT can be considered as a good alternative to the conventional methods of trochleoplasty.

Short-term outcomes for surgical correction of feline medial patellar luxations via semi-cylindrical recession trochleoplasty

Case series summary

Three cats (five stifles) were diagnosed with varying degrees of pelvic limb lameness secondary to medial patellar luxations (MPLs). Lameness did not resolve with medical management in any cat before referral for orthopedic evaluation. All cats underwent semi-cylindrical recession trochleoplasty (SCRT), medial fascial release and lateral imbrication for surgical repair of MPLs. All cats were re-evaluated at 3 and 8 weeks postoperatively and two cats were also evaluated at 16 weeks postoperatively. At the final rechecks, all cats had resolution of lameness of the operated limb(s) and no evidence of recurrence of patellar luxation.

Relevance and novel information

This case series demonstrated SCRT with soft tissue reconstruction as an acceptable option for surgical correction in three cats with MPLs. Short-term outcomes revealed minor complications and all patellae remained centralized.

Comparison of Hindlimb Conformation in Cats with and without Medial Patellar Luxation

OBJECTIVES

 Medial patellar luxation (MPL) is the most common developmental cause of hindlimb lameness in cats. The association between femoral and tibial conformation and MPL measured on computed tomography (CT) has not been reported in cats. The aims were to report femoral and tibial conformation in cats with and without MPL and to report normal femoral and tibial angles.

METHODS

 Angle of inclination of femoral neck (AI), anatomical lateral distal femoral angle (aLDFA), femoral trochanteric angle (FCT), angle of anteversion of femoral neck (AA), distal and proximal anteversion angle (DAA/PAA), overall tibial valgus (TV), tibial torsion (TT), tibial tuberosity displacement (TTD) and trochlear depth:patellar thickness ratio (T:P) were measured by three observers on CT of cats with and without MPL. Comparisons were made between groups. Inter-observer intraclass correlation coefficient (ICC) was calculated.

RESULTS

 Sixteen cats were recruited: eight control and eight with MPL. The aLDFA, PAA, TT, TTD and T:P were significantly less in cats with high-grade MPL. The AI, FCT, AA, DAA and TV were not significantly different. A high correlation was shown with inter-observer ICC in 33.33% and good correlation in 26.67% when comparing measurements between observers.

CLINICAL SIGNIFICANCE

 This study suggests that cats with high-grade MPL have decreased TT, TTD and T:P and may require tibial tuberosity transposition and femoral trochleoplasty. The PAA, TT and aLDFA were decreased, although clinical significance may vary and these cats may not require correctional osteotomies. Results should be interpreted with caution as high/good levels of inter-observer ICC occurred in less than two-thirds of cases between observers.

Case report: Block recession calcaneoplasty of the calcaneal tuber for treating lateral superficial digital flexor tendon luxation in a dog

A 4-year-old, intact, female, Collie was presented with 5 month history of right hindlimb lameness. Lateral luxation of the superficial digital flexor tendon (SDFT) was diagnosed on the basis of the clinical, radiographic and ultrasonographic finding. Intraoperatively, shallow right calcaneal tuber was observed. Block recession calcaneoplasty with retinaculum repair using anchor screw were performed to manage SDFT luxation. Additionally, temporary restraining pin was placed on lateral aspect of the calcaneal tuber. The patient demonstrated mild lameness at 2 weeks postoperatively and improved to normal limb function at 12 weeks postoperatively. As the gold standard of surgical techniques for SDFT luxation has not yet been reported, block recession calcaneooplasty may be an alternative surgical option for patients with calcaneal morphologic abnormalities causing SDFT luxation.

Computed Tomographic Measurements of the Sulcus Angle of the Femoral Trochlea in Small-Breed Dogs with and without Medial Patellar Luxation

Trochleoplasty is often performed in dogs with medial patellar luxation (MPL); however, the current guidelines on when to perform a trochleoplasty in dogs are vague. The sulcus angle (SA) is used to assess the femoral trochlear morphology in humans. The aim of this study is to describe a method to measure the SA and other parameters of trochlea morphology in dogs using computed tomography. First, we searched for a suitable measuring location for the SA. Transverse images of the femurs were obtained as perpendicular planes to the tangent of the femoral trochlea which was 0 to 60 degrees (every 5 degrees) to the anatomical axis of the femur. The deepest point of the femoral trochlea was found in the transverse images perpendicular to the tangent of the femoral trochlea which was at 15 degrees to the anatomical axis of the femur. The SA and the other parameters of femoral trochlea morphology were measured at the deepest point of the femoral trochlea. The SA of the stifle joints with grade 3 and 4 MPL was significantly higher than the SA of stifle joints not affected by MPL. There was no significant difference in the SA between dogs affected by grade 1 and 2 MPL and dogs not affected by MPL. Further studies are needed to establish whether the SA can be used as selection criteria for trochleoplasty.

Failure of Passive Transfer in Camel Calves: 4 Cases (2010-2019)

Failure of passive transfer is a management concern for all ruminant species, but is not well described in the literature for camel calves. This case series presents four camel calves (Camelus dromedarius and Camelus bactrianus) referred to a North American veterinary teaching hospital for diagnosis and management of failure of passive transfer. Diagnostics utilized included hematology, serum biochemistry, and immunologic methods as described for crias. Management included antimicrobial, anti-inflammatory, and plasma transfusion therapies. Three of the four calves survived to discharge, and common diagnostic practices such as evaluation of total solids, total protein, immunoglobulin G, and sodium sulfite appear to be correlate to passive transfer status in these four calves. Xenotransfusion with llama plasma was well tolerated by two calves, and xenotransfusion with bovine plasma was well tolerated by an additional calf in this study. An additional work is necessary to develop validated breakpoints for diagnosis of passive transfer status in camel calves.

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.

Tibial tuberosity transposition advancement for treatment of concomitant cranial cruciate ligament rupture and medial patellar luxation in four feline stifles

Case series summary

Three cats (four stifles) were diagnosed with varying grades of medial patellar luxation and stifle instability in cranial tibial thrust. Radiographs showed periarticular osteophytosis, intra-articular mineralization and opacification encroachment of the infrapatellar fat pad. Stifle exploration revealed either partial (n = 2) or complete (n = 2) cranial cruciate ligament tear and medial meniscal injury in all cases. Medial meniscectomy, partial parasagittal patellectomy, femoral trochleoplasty and tibial tuberosity transposition advancement using a 6 mm cage, two-fork plate and 4 mm spacer were performed in four stifles. Screws (2.0 mm) and washers were used in the cranial cage ears rather than conventional 2.4 mm screws. By the 2-week recheck, lameness was minimal and stifles were stable. Radiographic follow-up at 8 weeks showed appropriate progression of osseous union in all cases. One cat experienced a major complication, suffering tibial fracture following a lapse in exercise restriction, and revision surgery was performed successfully with subsequent osseus union of the osteotomy site. At the mid-term follow-up, all cats had a return to previous level of function, as assessed by both owner questionnaire and clinical evaluation.

Relevance and novel information

Tibial tuberosity transposition and advancement has been shown to be successful in dogs for the treatment of concomitant medial patellar luxation and cranial cruciate ligament rupture. To date, there have been no reports of tibial tuberosity transposition and advancement in cats. A benefit of this approach is concomitant alignment of the extensor mechanism and neutralization of the femorotibial shear force. Our case series describes successful use of tibial tuberosity transposition advancement in cats.

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.

Computed Tomographic Measurement of Trochlear Depth in Three Breeds of Brachycephalic Dog

OBJECTIVE

 The aim of this study was to determine the trochlear sulcus depth of three common brachycephalic breeds at risk of medial patellar luxation.

STUDY DESIGN

 Retrospective blinded clinical study using a previously validated ratio (T/P) of maximal trochlear sulcus depth (T) and maximal patellar craniocaudal thickness (P) measured on computed tomography, to assess trochlear sulcus depth in Pugs, French Bulldogs and English Bulldogs without clinical patellar luxation. The effect of breed on T/P was assessed using one-way linear regression models.

RESULTS

 The mean T/P was affected by breed (p < 0.001). There was significant difference between Pugs (0.45) and French Bulldogs (0.38) and between Pugs and English Bulldogs (0.4). There was no significant difference between Pugs and previously published data for non-brachycephalic and mixed breed dogs (0.46) (p = 0.39). Mean T/P was significantly reduced in the brachycephalic dog breeds combined compared with the previously published data (p < 0.001).

CONCLUSION

 The trochlear sulcus varies by breed and was more shallow in French and English Bulldogs than Pugs, hence a shallow sulcus may be a breed-driven characteristic. The three breeds assessed are at risk of patellar luxation but sulcus depth did not directly correlate with previously published risk factors-the contribution of sulcus depth to the aetiopathogenesis of patellar luxation remains unclear. Trochlear recession to achieve patellar coverage of 50% may be excessive considering maximal breed normal depth.

Comparison of Semi-Cylindrical Recession Trochleoplasty and Trochlear Block Recession for the Treatment of Canine Medial Patellar Luxation: A Pilot Study

OBJECTIVE

 The aim of this study was to describe an alternative method for trochleoplasty, semi-cylindrical recession trochleoplasty (SCRT), and compare it to trochlear block recession (TBR) in regard to recessed trochlear depth, patellar depth, patellar articular contact with the trochlea, recessed trochlear surface area, procedure time, complications and functional outcome.

STUDY DESIGN

 Ten dogs with bilateral grade II-III medial patellar luxations underwent bilateral simultaneous correction surgery including tibial tuberosity transposition, lateral imbrication and trochleoplasty with one stifle each undergoing TBR and SCRT. Patients received pre-and postoperative stifle computed tomography scans and pre- and 8-week postoperative pressure platform analysis and physical examinations. Recessed trochlear depth, patellar depth, trochlear surface area, patellar articular contact, procedure time, complications and functional outcomes as measured by gait analysis were compared between the two techniques.

RESULTS

 There was no significant difference in measured outcome variables between techniques at any time point. At the time of the 8-week reassessment, no patella had reluxated.

CONCLUSION

 Short-term follow-up shows similar functional outcomes between both techniques regarding rate of reluxation and limb function. The SCRT was subjectively easier to perform than TBR, particularly in small patients. The SCRT is an acceptable method of trochleoplasty for the treatment of medial patellar luxation in dogs and further studies evaluating long-term outcomes are justified.

Segmental Femoral Ostectomy for the Reconstruction of Femoropatellar Joint in Dogs with Grade IV Medial Patellar Luxation

OBJECTIVE

 The aim of this study was to describe a new surgical method of segmental femoral ostectomy for the reconstruction of the femoropatellar joint (FPJ) in dogs with medial patellar luxation (MPL) grade IV.

STUDY DESIGN

 The medical records of six dogs that underwent segmental femoral ostectomy to reconstruct the FPJ for MPL grade IV were retrospectively reviewed. The data included breed, age, body weight, comorbidities, history of orthopaedic abnormalities, pre- and postoperative radiographic findings, morphological indicators measured on three-dimensional computed tomographic multiplanar reconstruction images, surgical methods and postoperative complications.

OUTCOMES

 Eleven hindlimbs with MPL grade IV in six dogs underwent segmental femoral ostectomy to reconstruct the FPJ with the four basic surgical procedures. Six stifle joints with femoral varus deformity were treated by closing wedge ostectomy and segmental ostectomy, while five stifle joints were treated by segmental ostectomy alone. The mean resected femoral length was 11.7 mm. The mean resected femoral length relative to the preoperative femoral length was 14.3%. The stability and congruity of the FPJ was markedly improved, with an increased range of motion in all dogs compared with their preoperative status.

CONCLUSION

 Segmental femoral ostectomy was a useful treatment method for MPL grade IV with shortened quadriceps muscle length relative to the femoral length. Reconstruction of the FPJ is important for recovery of limb function.

Computed tomographic localization of the deepest portion of the femoral trochlear groove in healthy dogs

OBJECTIVE

To validate a computed tomographic (CT) method to measure the femoral trochlear groove depth (FTGD).

STUDY DESIGN

Cadaveric study.

SAMPLE POPULATION

Fifteen dogs, 26 femoral trochleae.

METHODS

Five points were identified from proximal to distal (proximal point [PP], P25, P50, P75, and distal point [DP]) along the trochlea via three-dimensional volume-rendering function on the sagittal plane and measured on multiplanar reconstruction images. Each rater repeated measurements in duplicate, unaware of the identity of the joint. The FTGD was quantitated on the anatomical specimens and statistically compared with CT measurements. Intrarater and interrater agreements were analyzed by using intraclass coefficients. Accuracy was evaluated by using either adjusted R² coefficients (R²  > 80% was considered acceptable) or Student's t test. The ratio of the patellar and the trochlear width and the ratio of the patellar craniocaudal thickness inside the trochlear groove were calculated at three different patellar locations.

RESULTS

Good to excellent intrarater and interrater agreements were observed in four of five trochlear points (P25, P50, P75, and DP), and accuracy was acceptable for these points (R²  > 80%). Computed tomographic measurements differed from the mean anatomical measurements at three of five points (PP, P50, and P75; P < .01), overestimating the FTGD by an overall mean of 0.18 mm (range, 0.02-0.3). P25 and P50 were the deepest points measured.

CONCLUSION

Computed tomography allowed precise measurements of trochlear groove depth except for the most proximal point. The deepest trochlear points were P25 and P50. P25 was the most precise and accurate point measured, while PP was the least consistent.

CLINICAL SIGNIFICANCE

The deepest portion of the trochlea groove may be located between P25 and P50. Evaluation of this CT method in dogs with patellar luxation is recommended.

Patellar luxation in dogs

Patellar luxation is a common orthopedic problem in dogs. Medial luxation is more common than lateral luxation and is usually diagnosed in dogs of small breed. Diagnosis is based on clinical evidence of patellar instability; however, diagnostic imaging is required to assess the amount of skeletal deformity and then the most appropriate method of treatment. Surgical options include both soft tissue and osseous techniques, however, in most of the cases, a combination of more procedures is used to achieve the correction of the luxation. Complication rate is generally low and the most common complications include reluxation and implant-associated complications. Prognosis is generally favorable, with most of the dogs returning to normal limb function. This article describes patellar luxation features in dogs, including clinical presentation, diagnosis, and treatment options available.

Distal tibial tuberosity translation using TTA implants for the treatment of patella alta in large breed dogs

Introduction: Medial patellar luxation frequently occurs in dogs resulting in lameness with increasing incidence in large breed dogs. Patella alta has been defined as a patellar ligament length to patellar length ratio that is greater than two and may predispose to patellar luxation.

Objective: To describe the surgical technique for stabilization of the distal translation of the tibial tuberosity using tibial tuberosity advancement plates and the clinical outcomes with follow-up for clinical cases of dogs.

Methods: Dogs that were presented with the complaint of patellar luxation and that were concurrently diagnosed with patella alta and were greater than 20 kg in body weight underwent surgery using a tibial tuberosity advancement plate to stabilize the osteotomy. Radiographic assessment of A:PL distance (the ratio of the proximal aspect of the patella to the femoral condyle [A] to the patellar length [PL]), L:P ratio (ratio of the length of the patellar ligament to the diagonal length of the patella), and owner assessment were obtained.

Results: Eleven stifles in nine dogs underwent surgical correction with a mean preoperative L:P ratio of 2.47. There were no complications and the lameness resolved clinically. The mean A:PL ratios preoperatively (2.6 ± 0.22) and postoperatively (2.1 ± 0.25) were significantly different (p = 0.0003). All owners were satisfied with the outcome and all dogs had a resolution of lameness with no recurrence of patellar luxation.

Clinical significance: Stabilization of distal translation of the tibial tuberosity using tibial tuberosity advancement implants to correct patella alta in large breed dogs was feasible and resulted in good clinical outcome.

Latero-distal transposition of the tibial crest in cases of medial patellar luxation with patella alta

Medial patellar luxation is defined as medial displacement of the patella from the trochlear groove. In dogs, medial luxations account for 75% of all patellar luxation cases, and are frequently associated with patella alta. Common surgical treatments for medial luxation are trochleoplasty and lateral transposition of the crest to drive the patella into the correct anatomical alignment. Postoperative complications for this procedure are estimated to be between 18–29% of cases, with up to 48% of complications involving reluxation. It was previously hypothesized that in cases of medial luxation involving patella alta, the addition of a distal component to the lateral tibial crest transposition will result in repositioning of the patella into its proper position in the trochlear groove, thus reducing the recurrence of luxation. We performed this modified procedure on 14 dogs (17 limbs) that were suffering from medial luxation combined with patella alta, and our results led to favourable clinical outcomes. This modified surgical procedure places the patella into a more normal proximodistal anatomical position, is simple to perform, and may become common practice for surgical treatment of medial patellar luxation with an alta component.

Prevalence, treatment and outcome of patellar luxation in dogs in Italy

Objective: To determine the prevalence of patellar luxation in dogs in Italy and its relation to signalment, the frequency and the type of postoperative complications and the outcome of treatment, and to compare the findings with those of other studies.

Materials and methods: The medical records from four referral clinics were searched for dogs with orthopaedic disorders referred from 2009 to 2014. From these data, the records of dogs with patellar luxation were identified, and the signalment, age and body weight, grade, side and direction of patellar luxation, treatment, postoperative complications, and outcome were retrieved. Univariate and multivariate statistical analyses were used to evaluate the data.

Results: Of 8,694 canine orthopaedic cases, fractures not included, patellar luxation was diagnosed in 559 dogs (801 stifles). Mixed breed dogs were most commonly affected (18%), 85% of the luxations were medial, and 52% of the dogs were female. Of the 559 dogs examined, 400 (574 stifles) met the inclusion criteria for treatment evaluation. Minor complications occurred in five percent of the dogs, and major complications in 16%, including recurrence of patellar luxation in seven percent of the dogs. The outcome was good in 88% of stifles, fair in two percent, and poor in 10%.

Clinical significance: Although patellar luxation was more common in small breed dogs, it also was diagnosed in a significant number of large breed dogs, which included medial patellar luxation in 73% and lateral patellar luxation in 27% of stifles. Body weight and grade of luxation were the only variables statistically correlated with surgical complications.

ORCID iD AV: http://orcid.org/0000-0003-2837-7822

Short-term effects of arthrotomy with and without infrapatellar fat pad resection on the normal canine stifle

OBJECTIVE

To investigate the short-term effects of infrapatellar fat pad (IFP) resection in normal dogs.

STUDY DESIGN

Experimental in vivo study.

ANIMALS

Five normal adult female beagle dogs.

METHODS

The IFP was resected via arthrotomy in the left stifle joint (experimental side) while the right stifle underwent arthrotomy alone (sham side). An orthopedic examination was performed every week for 4 weeks and synovial fluid was analyzed before and 4 weeks after the procedure. The ratio of the length of the patellar ligament to the patellar length (L:P) was calculated on a lateral radiograph of the stifle before, 2 and 4 weeks after the procedure. Patellar depth (PD) and the contact area (CA) between the femur and patella were calculated from computed tomographic images taken at 3 different stifle angles (extended, flexed, hyperflexed) before, immediately after, and 4 weeks following the procedure. The dogs were euthanatized 4 weeks after the procedure for macroscopic and microscopic evaluation of the patellofemoral joint.

RESULTS

No difference was found between treatment groups throughout the study. No evidence of postoperative osteoarthritis was detected in any of the dogs. Orthopedic examinations, radiographs, and synovial fluid analyses remained within normal limits. Most PD, but not CA measurements, increased with time in both joints and at all stifle angles.

CONCLUSIONS

Excision of the IFP subsequent to medial arthrotomy did not result in any measurable changes in the canine patellofemoral joint when compared with medial arthrotomy alone after 4 weeks of follow-up.

The epidemiology of patellar luxation in dogs attending primary-care veterinary practices in England

BACKGROUND

Canine patellar luxation is one of the most common orthopaedic disorders of dogs and is a potential welfare concern because it can lead to lameness, osteoarthritis and pain. However, there are limited epidemiological data on the disorder relating to the general population of dogs in England. This study aimed to investigate the VetCompass Programme database of dogs attending primary-care veterinary practices in England to report on the prevalence, risk factors and clinical management of diagnosed patellar luxation cases.

RESULTS

The study included all dogs with at least one electronic patient record in the VetCompass database from September 1(st), 2009 to August 31(st), 2014. Candidate patellar luxation cases were identified using free-text word searching of the clinical notes and VeNom diagnosis term fields. Univariable and multivariable binary logistic regression modelling was used for risk factor analysis. The overall dataset comprised 210,824 dogs attending 119 clinics in England. The prevalence of patellar luxation diagnosis in dogs was 1.30 % (95 % confidence interval (CI) 1.21-1.39). Of the 751 incident cases, 293 (39.0 %) received medical management, 99 (13.2 %) received surgical intervention and 28 (3.7 %) were referred for further management. Multivariable modelling documented 11 breeds with increased odds of patellar luxation compared with crossbred dogs, including the Pomeranian (odds ratio [OR]: 6.5, 95 % CI 4.0-10.7, P < 0.001), Chihuahua (OR: 5.9, 95 % CI 4.4-7.9, P < 0.001), Yorkshire Terrier (OR: 5.5, 95 % CI 4.3-7.1, P < 0.001) and French Bulldog (OR: 5.4, 95 % CI 3.1-9.3, P < 0.001). Dogs with bodyweight below their mean for breed and sex had a 1.4 times odds of diagnosis (95 % CI 1.2-1.6, P < 0.001). Dogs aged ≥ 12.0 years showed 0.4 times the odds (95 % CI 0.3-0.5, P < 0.001) compared with dogs aged < 3.0 years. Females had 1.3 times the odds (95 % CI 1.1-1.5, P < 0.001), neutered dogs had 2.4 times the odds (95 % CI 1.8-3.2, P < 0.001) and insured dogs had 1.9 times the odds (95 % CI 1.6-2.3, P < 0.001).

CONCLUSIONS

Patellar luxation warrants inclusion as a welfare priority in dogs and control strategies that include this disorder should be considered as worthwhile breeding goals, especially in predisposed breeds.

Kite Shield-Shaped Wedge Recession for Treatment of Medial Patellar Luxation in Seven Small-Breed Dogs

OBJECTIVE

To document the trochlear depth (TD) and clinical outcome after kite shield-shaped wedge (K-wedge) recession trochleoplasty in toy-breed dogs with medial patellar luxation (MPL).

STUDY DESIGN

Case series.

ANIMALS

Seven toy-breed dogs (<5 kg) with uni- or bilateral grades II-IV MPL (10 stifles).

METHODS

A K-wedge recession trochleoplasty was performed in all dogs in combination with other surgical procedures as treatment for MPL. The TD, the ratio of the proximal TD to patella thickness, and the presence of osteophytes were determined from computed tomography images taken pre-, and 1 and 12 months postoperative. Lameness scores and MPL grade were also recorded.

RESULTS

The TD and the ratio of proximal TD to patella thickness increased significantly immediately postoperative and remained increased at 1 and 12 months postoperative. The osteophyte score was significantly higher at 12 months postoperative than preoperative. All dogs had a reduction in MPL grade and improvement in lameness postoperative.

CONCLUSION

K-wedge recession trochleoplasty was successful in treating MPL in a series of toy-breed dogs and offers an alternate to other trochlear recession techniques.

Lesions in canine stifle joints due to trochleoplasties as treatment for medial patellar luxation

Lesions in canine stifle joints after previous trochleoplasty surgery were documented. In four clinical cases arthrotomies were performed due to stifle pain after previous trochlear deepening procedures. A small area of hyaline cartilage remained in the groove of the stifles in cases where previous wedge trochleoplasties had been performed. All of the stifles had significant areas of eburnation on the axial aspect of the medial trochlear ridge. The stifle joints of a dog that was euthanased due to severe irreversible osteoarthritis were photographed. The dog had undergone previous surgery for patellar luxation and cranial cruciate ligament ruptures. The trochlear grooves in this dog had almost no visible articular cartilage left.

Complications associated with corrective surgery for patellar luxation in 85 feline surgical cases

The objective was to review surgical techniques and postoperative complications of surgical correction for patellar luxation (PL) in cats. A retrospective study evaluating 85 surgeries in 71 cats was performed. The records from four referral centres were searched for cats with surgical management of PL. Signalment, history, PL grade and direction, corrective surgical techniques and outcome were retrieved. Binary logistic regression analysis was used to interrogate relationships between case features, surgical correction methods and outcomes. The outcomes were classified as minor and major complications (requiring revision surgery), including continued PL (reluxation). Postoperative complications occurred in 26% of cases; 20% had major complications, including 5% patellar reluxation, and 6% had minor complications. Cats with previous ipsilateral femoral fracture were significantly more likely to suffer complications, including minor (P = 0.02, odds ratio = 12.67), major (P = 0.03, OR = 7.2) and patellar reluxation (P = 0.01, OR = 19.25). Minor complications were significantly more likely with grade 4 PL (P = 0.03, OR = 8.5). Major complications were significantly more likely with tibial tuberosity transposition (TTT; P = 0.03, OR = 5.57). Patellar reluxation was significantly more likely if stifle surgery had been performed previously (P = 0.05, OR = 8.00). The presence of bilateral PL, hip dysplasia, grade 1, 2 or 3 PL, corrective surgery using an anti-rotational suture or femoral sulcoplasty did not influence complications. Complications were more likely for grade 4 PL, previous ipsilateral femoral fracture, if TTT was performed and for cases with previous stifle surgery. This information allows consideration of risks and complicating factors.

Partial parasagittal patellectomy: a novel method for augmenting surgical correction of patellar luxation in four cats

We describe a novel surgical technique used to correct feline patellar luxation (PL) where abnormal patellar tracking persists despite conventional corrective surgery. An anatomical difference between feline and canine stifles is that the feline patella is wider relative to the trochlear sulcus. This results in less constrained patellar tracking. Therefore, patellar subluxation is common in normal cats. It was noticed that in some feline cases with clinically significant PL, PL persisted intraoperatively despite performing the standard corrective procedures. We report a novel surgical technique - partial parasagittal patellectomy - to address the wide shape of the feline patella relative to the sulcus. This technique has been successfully performed in four cats with good outcomes. However, the immediate risks and long-term effects of partial parasaggital patellectomy are not known. We reserve this technique for surgical cases where PL cannot be controlled by conventional means.

Medial ridge elevation wedge trochleoplasty for medial patellar luxation: a clinical study in 5 dogs

OBJECTIVE

To develop a surgical technique to elevate the medial trochlear ridge for surgical correction of medial patellar luxation, and to evaluate clinical outcome.

STUDY DESIGN

Case series.

ANIMALS

Dogs (n = 5) with Grade 3 medial patellar luxation.

METHODS

An asymmetrical wedge was removed from the trochlear groove, rotated 180°, and placed in the recess to create an elevated medial trochlear ridge. Postoperative radiography, CT scan, and subjective evaluation of clinical outcomes were performed.

RESULTS

Surgical procedure and postoperative recovery were uncomplicated. There was no recurrence of spontaneous luxation and subjectively, gait improved in all dogs. Postoperative radiographs and CT images confirmed the elevated medial trochlear ridge, a significantly increased groove depth/patellar thickness ratio (P < .01), and seating of the patella in the trochlear groove.

CONCLUSION

Elevating the medial trochlear ridge, instead of deepening the groove, can be considered a viable surgical technique to stabilize luxating patellae.

Management of bilateral patellar luxation in an alpaca

OBJECTIVE

To report surgical management bilateral lateral patellar luxation in a mature alpaca using a combination of trochlear wedge recession (TWR), tibial tuberosity transposition (TTT), and joint capsule imbrication.

STUDY DESIGN

Clinical case report.

ANIMALS

9-year-old castrated male Alpaca.

METHODS

Bilateral, grade III/IV, lateral patellar luxation was identified by palpation, lameness examination and confirmed with radiography and ultrasonography. Surgical procedures were staged, with the left stifle treated first. Bilateral TWR, TTT, and joint capsule imbrication were performed. Outcome was assessed by radiography and follow up lameness examinations.

RESULTS

An immediate improvement in weight bearing occurred after surgery of the left hind limb. Five months after initial surgery, right hind limb patella luxation was corrected. After surgery on the 2nd limb, the alpaca had progressive improvement in weight bearing during hospitalization. At 12 months, there were no signs of lameness and the alpaca had resumed normal activities.

CONCLUSIONS

For bilateral lateral patellar luxation, a combination of TWR, TTT, and joint capsule imbrication resulted in excellent long-term outcome.

Ilial crest bone graft transposition as treatment for fracture of the medial femoral trochlear ridge in a dog

This is a report of a fracture of the medial trochlear ridge of the distal femur occurring as a major complication after surgery for medial patellar luxation. To address the complication, a non-vascularized iliac bone graft was collected and fixated with two positional screws to the trochlea. An external skeletal fixator was placed to prevent motion of the stifle joint during the healing period and to reduce the risk for fragment dislodgment. One year after the graft was placed the dog's function was satisfactory. This case report indicates that a non-vascularized iliac bone graft provides an alternative for management of fractures of the medial ridge of the distal femur.

Hips, elbows and stifles: common joint diseases in the cat

PRACTICAL RELEVANCE

Cats commonly present with joint disease and trauma. A methodical approach to diagnostics and treatment can aid the clinician in the management of these cases.

CLINICAL CHALLENGES

Cats with joint disease may present with a vague history owing to their independent nature, and gait assessment is often challenging when compared with the dog. Knowledge of feline-specific anatomy is important to avoid over- or misinterpretation of physical examination or imaging findings.

AUDIENCE

This review of feline joint disease focuses on the more common, non-traumatic conditions of the hip, stifle and elbow. It aims to provide first opinion clinicians with a guide to decision making that will assist them in achieving a diagnosis and formulating a management strategy.

EVIDENCE BASE

There is an extensive body of original articles and textbooks in the published literature relating to aspects of feline joint disease. This article combines information from key companion animal and feline-specific references together with the author's clinical experience to provide a practical overview of joint disease, and highlight important differences between cats and dogs in terms of presentation and treatment.

Surgical treatment of medial patellar luxation without femoral trochlear groove deepening procedures in dogs: 91 cases (1998-2009)

OBJECTIVE

To assess signalment, outcomes, and complications for dogs surgically treated for medial patellar luxation (MPL) with a combination of lateral retinacular imbrication and tibial crest transposition procedures without femoral trochlear groove deepening techniques, and to determine whether osteoarthritis progressed in these patients during the 8-week period following surgery.

DESIGN

Retrospective case series. Animals-91 dogs.

PROCEDURES

Medical records were reviewed for information on signalment, clinical history, unilateral versus bilateral disease, preoperative and postoperative MPL grades, duration of follow-up, and perioperative and postoperative complications. Radiographs obtained preoperatively and during 8-week follow-up examinations were reviewed and assigned degenerative joint disease (DJD) scores (range, 0 to 3). Data were analyzed to determine factors influencing outcomes. Kaplan-Meier curves were constructed for recurrence of MPL.

RESULTS

Minor postoperative complications were reported for 31 of 91 (34.1%) dogs. Patellar reluxation occurred in 18 of 91 (19.8%) dogs. Reluxation or complications for which additional surgery was recommended developed in 6 of 91 (6.6%) dogs. At last clinical follow-up, 10 of 91 (11.0%) dogs had at least occasional lameness. No difference was revealed between preoperative and postoperative (8-week follow-up) radiographic DJD scores.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of surgical treatment of MPL without femoral trochlear groove deepening procedures were comparable to those in studies of surgical treatment that included groove deepening procedures. Radiographic indices of DJD did not increase during the 8 weeks following surgery. These results suggest that trochlear groove deepening procedures are not always necessary, and patients that undergo these techniques should be carefully selected.

Trochlear block recession in an alpaca with traumatic lateral patellar luxation

OBJECTIVE

To report surgical treatment of traumatic lateral patellar luxation using trochlear block recession in an alpaca.

STUDY DESIGN

Clinical case report.

ANIMALS

Five-year-old female alpaca.

METHODS

Grade IV/IV lateral, left patella luxation and mild femoropatellar joint effusion was identified by palpation and visual assessment, and confirmed by ultrasonography and radiographs. Trochlear block recession combined with lateral retinacular release and medial imbrication to restore patella function.

RESULTS

Progressive improvement in weight bearing occurred during hospitalization (6 days) and at 3.5 weeks, no lameness was observed; radiographically, the patella was in normal anatomic alignment. At 15 months, there were no signs of lameness with unrestricted exercise and the alpaca had given birth to another cria.

CONCLUSIONS

In this alpaca with traumatic origin of the lateral patellar luxation and normal femoro-tibial alignment, a combination of retinacular imbrication, contralateral release, and trochlear block recession were successful for long-term treatment of lateral patellar luxation.

CLINICAL RELEVANCE

Although trochlear block recession is most commonly performed in small animals, this technique may be useful in treatment of traumatic patellar luxations in camelids.

Patellar luxation in 70 large breed dogs

OBJECTIVES

To report the signalment, history, clinical features, and outcome in dogs weighing greater than 15 kg, treated surgically and non-surgically for patellar luxation. Risk factors for the development of patellar luxation, postoperative complications, and outcome were evaluated.

METHODS

Details regarding signalment, bodyweight, breed, aetiology, unilateral or bilateral luxation, duration of lameness, grade of luxation, direction of luxation, grade of lameness at presentation, concomitant cranial cruciate ligament rupture, method of treatment, surgical technique, surgeon, and complications were obtained from the medical records. Outcome was graded as excellent, good, fair, or poor, according to the degree of lameness.

RESULTS

Seventy dogs (45 males and 25 females) were included. Thirty-five had bilateral luxations (105 limbs). Mean age was two years, and mean weight was 30 kg. The relative risk for Labrador retrievers was 3.3 (P<0.001). All luxations were developmental. Luxations were medial in 102 stifles and lateral in three. Fourteen stifles had concomitant cranial cruciate ligament rupture. As the grade of patellar luxation increased, so did the grade of lameness (P<0.001). Surgery was performed in 70 stifles, and outcome was excellent/good in 94 per cent and fair/poor in 6 per cent of stifles. Complications occurred in 29 per cent of stifles, and increasing bodyweight was found to be a risk factor (P=0.03). Thirty-five stifles were managed non-surgically, and outcome was excellent/good in 86 per cent and fair/poor in 14 per cent of stifles.

CLINICAL SIGNIFICANCE

In view of the potential risk of postoperative complications, all surgically treated cases of patellar luxation in large breed dogs should be managed with a femoral trochleoplasty, a tibial tuberosity transposition (stabilised with K-wires and a tension band wire), and soft tissue releasing and tightening procedures.

Complications associated with corrective surgery for patellar luxation in 109 dogs

OBJECTIVE

To review surgical techniques and postoperative complications associated with correction of patellar luxation in dogs.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n = 109) with patellar luxation (n = 131).

METHODS

Medical records of dogs that had corrective surgery for patellar luxation were reviewed. Signalment, history, grade and direction of patellar luxation, operative technique and clinical outcomes were retrieved.

RESULTS

Overall frequency of postoperative complications was 18%. Frequency of major (requiring revision surgery) complications was 13%. Frequency of patellar reluxation was 8%. Frequency of overall, major, and patellar reluxation complications was higher for dogs weighing > or =20 kg compared with those <20 kg. Frequency of overall and major complications was higher for dogs with higher grades of patellar luxation. Femoral trochlear sulcoplasty resulted in lower frequency of patellar reluxation. Tibial tuberosity transposition (TTT) resulted in lower frequency of major complications and patellar reluxation. Retinacular/capsular release resulted in higher frequency of major complications. Patient age, gender, medial versus lateral patellar luxation, left versus right hindlimb, capsular/retinacular imbrication, use of anti-rotational sutures, and whether stifle surgery had been performed previously did not significantly influence frequency of complications.

CONCLUSION

TTT and femoral trochlear sulcoplasty minimize the risk of postoperative patellar reluxation and major complications.

CLINICAL RELEVANCE

Information derived from this study can be used to estimate the likelihood of postoperative complications for canine patients undergoing corrective surgery for patellar luxation.

Pre- and postoperative radiographic and computed tomographic evaluation of dogs with medial patellar luxation

OBJECTIVE

To quantify, using radiographic and computed tomographic (CT) techniques, the effects of surgical procedures most commonly combined to treat dogs with medial patellar luxation (MPL).

STUDY DESIGN

Prospective study.

METHODS

Six dogs with 8 MPL were studied. Radiographs and CT of the pelvic limbs were obtained before and immediately after soft-tissue reconstruction, trochlear wedge recession, and tibial crest transposition. Radiographic measurements included angle of inclination, Norberg angle, quadriceps angle (QA), anteversion angle, ratio of the length of the patellar tendon (PT) to the length of the patella, and change in patella tendon angle. CT measurements included angle of inclination, Norberg angle, QA, anteversion angle, depth of the femoral trochlear groove, ratio of the middle femoral trochlear groove depth to the patella thickness, and tibial crest alignment.

RESULTS

Conformation of the coxofemoral joint was not affected by surgery. Surgical treatment corrected the QA by 33-58%. Trochlear wedge recession was most effective in deepening the proximal trochlea by 103.5%. The ratio of the middle femoral trochlear groove depth to the thickness of the patella postoperatively resulted in 50% coverage of the patella. Tibial crest transposition resulted in caudalization of the PT by 8.5+/-3.0 degrees, with lateralization of the tibial tuberosity of 11.3 degrees.

CONCLUSION

The effects of surgery for MPL can be quantified with radiographic and CT measurements. Surgical correction restored the alignment of the quadriceps and adequately deepened the femoral trochlear groove. Tibial crest transposition resulted in caudalization of the patella tendon and lateralization of the tibial tuberosity.

CLINICAL RELEVANCE

These pilot data quantified the effects of surgical procedures most commonly combined to treat MPL. We hope to use these measurements to correlate surgical treatment with functional outcome and postoperative occurrence of luxation.