Surgical Technique of the 3-Dimensional-printed Personalized Hip Implant for the Treatment of Canine Hip Dysplasia.

Hip dysplasia causes major disability in dogs. Treatment options are limited to palliative treatment (e.g., pain relief, physical exercise, lifestyle changes, and weight control) or invasive surgeries such as pelvic osteotomies and total hip arthroplasty. Hence, a strong unmet need exists for an effective and dog-friendly solution that enhances the quality of life of man's best friend. We fill this treatment gap by offering a minimally traumatic and extraarticular, dog-specific, 3-dimensional-printed, hip implant (3DHIP) that restores hip joint stability. The surgical treatment using a 3DHIP implant is less invasive than osteotomies and can be performed bilaterally in one surgical session. The 3DHIP implant extends the dorsal acetabular rim of the dysplastic hip joint thereby increasing coverage of the femoral head and inhibiting joint subluxation with fast recovery. Sufficient access to the dorsal acetabular rim and ventral border of the iliac body together with optimal fitting and fixation of the implant are key steps for a successful 3DHIP implantation and imply the need for a specific approach. The present article aims to showcase this innovative surgical technique with tips and tricks as a surgical manual for implantation of the 3DHIP implant in dogs affected by hip dysplasia.

Complications and outcomes of total hip arthroplasty in dogs with luxoid hip dysplasia: 18 cases (2010-2022).

OBJECTIVE: To describe the complications and outcomes in dogs with luxoid hip dysplasia (LH) undergoing total hip arthroplasty (THA) and compare complication rates with THA in non-LH dogs. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Client-owned dogs (n = 217) undergoing primary THA (n = 238). METHODS: Medical records (2010-2022) of dogs undergoing THA were reviewed, and LH was defined as complete dorsal displacement of the femoral head from the acetabulum on lateral projection radiographs. Major or catastrophic complications, revisions, and outcomes were recorded for all dogs and they were compared between LH and non-LH groups. RESULTS: Eighteen cases met the subcriterion for the LH group and 220 cases met the subcriterion for inclusion in the non-LH group. There were 14 complications in 13/18 dogs with LH; seven were intraoperative (femoral fissure/fracture) and seven were postoperative (dorsal luxation, n = 5; femoral fracture, n = 1; acetabular cup septic loosening, n = 1). Revisions were performed for all LH dogs that encountered complications; satisfactory outcomes were achieved in 12/13 dogs. Overall, LH dogs had a higher risk of developing complications (p < .001), including intraoperative fracture (p < .001) and postoperative dorsal luxation (p = .019) when compared with non-LH dogs. CONCLUSION: Luxoid hip dysplasia was associated with a higher risk of major complications following THA in dogs, specifically intraoperative fissure/fracture and postoperative dorsal luxation. Despite the increased risk, revisions typically yielded satisfactory outcomes. CLINICAL SIGNIFICANCE: Luxoid hip dysplasia is an important risk factor for the development of major complications in dogs undergoing THA.

Physical Rehabilitation for the Management of Canine Hip Dysplasia: 2021 Update.

Hip dysplasia is one of the most common orthopedic conditions affecting dogs. Initially, laxity of the femur leads to subluxation, and subluxation can lead to an abnormal development or to progressive degeneration of the femoral head and dorsal acetabular rim. Osteoarthritis and its clinical impact progress over time. Changes to the femoral head and neck and the acetabulum and the impact on joint motion and pain vary widely among dogs. The rehabilitation of dogs with hip dysplasia includes rehabilitation therapy in dogs managed conservatively and the rehabilitation of dogs managed with surgery.

Clinical outcomes of double pelvic osteotomies in eight dogs with hip dysplasia aged 10-28 months.

OBJECTIVE: To report the short-term outcome of double pelvic osteotomy (DPO) in dogs with canine hip dysplasia ≥10 months of age. STUDY DESIGN: Case series. ANIMALS OR SAMPLE POPULATION: Eleven hips in eight dogs aged between 10 to 28 months. METHODS: Dogs clinically affected by hip dysplasia with a hip reduction angle <40°, subluxation angle <25°, dorsal acetabular rim angle between 7.5-25°, and minimal osteoarthritic changes were considered as candidates for DPO. The clinical outcome was subjectively assessed using a lameness score and pain scale upon hip extension. Norberg angle, percentage of the area of the femoral head coverage, percentage of linear femoral head coverage, pelvic width dimensions were measured on pre and postoperative radiographs. RESULTS: At the 8-week follow-up examination, all the dogs had no lameness with no pain upon hip extension. Median Norberg angle increased by 21.8% (p < .01), median percentage of the area of the femoral head coverage increased by 66.7% (p < .01) and percentage of linear femoral head coverage increased by 162.5% (p < .01) 1 year after DPO. No changes to pelvic canal width after DPO were detected. CONCLUSION: Double pelvic osteotomy improved joint congruity and clinical signs in dogs affected by hip dysplasia without osteoarthritis that were ≥10 months of age. CLINICAL SIGNIFICANCE (OR IMPACT): Double pelvic osteotomy may be a treatment option for dogs with hip dysplasia ≥10 months of age. A large study assessing long-term outcomes is indicated.

Triple pelvic osteotomy with a 12.5° and a 20° Slocum-type plate: A short-term prospective clinical pilot study in 38 dogs.

OBJECTIVE: To determine whether using 12.5° Slocum-like triple pelvic osteotomy (TPO) plates would create sufficient femoral head coverage and lower the occurrence of overrotation compared with using 20° TPO plates in dogs with hip dysplasia. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Thirty-five dogs with hip dysplasia (38 hips). METHODS: Nineteen hips were surgically treated with a custom-made Slocum-type 12.5° TPO plate, and these were matched to 19 hips surgically treated with a 20° commercial Slocum TPO plate. Hips were case matched according to size and breed. Ortolani sign, angles of subluxation and reduction, distraction index, and femoral head coverage (FHC) were compared between groups. Excessive coverage was defined as >80%. RESULTS: In the 12.5° group, FHC was ≥50% in all hips, with mean FHC (67%), gain (37%), and excessive coverage (11%) all significantly less than in the 20° group (79%, 54%, and 42%, respectively). CONCLUSION: The 12.5° plate produced sufficient FHC compared with the 20° plate, with fewer hips with excessive coverage. CLINICAL SIGNIFICANCE: The 12.5° TPO plate may result in sufficient FHC with a lower occurrence of excessive coverage compared with 20° plates.

Total hip arthroplasty to address chronic hip luxation with pseudoacetabulum formation in seven dogs.

OBJECTIVE: To compare the outcome of dogs treated with total hip arthroplasty (THA) for chronic hip luxation and pseudoacetabulum formation to that of dogs with simple hip dysplasia and secondary osteoarthritis. STUDY DESIGN: Retrospective, case-controlled study. ANIMALS: Seven dogs with pseudoacetabulum (group 1) and 21 matched control dogs (group 2). METHODS: Each dog in group 1 was matched with three control dogs, primarily according to similarity of THA implant type and size. Patterns of radiographic pathology were characterized in each dog. Outcome measures included operative time, acetabular cup position/orientation (inclination angle, angle of lateral opening, version angle) complications, and long-term outcomes. Outcome measures were compared between groups using linear regression (P = .05). RESULTS: The presence of a pseudoacetabulum was associated with ilial remodeling and heterotopic bone formation concentric to the luxated femoral head. Exposing the native acetabulum and reducing the prosthesis were surgically challenging. The mean (SD) operative time of dogs in group 1 (96 [18] minutes) was longer than that of dogs in group 2 (63 [14] minutes; P = .00002). Cup position/orientation was not different between dogs in group 1 and group 2. One intraoperative complication and two minor postoperative complications occurred in group 1 dogs. All dogs had good long-term outcomes. CONCLUSION: Total hip arthroplasty in dogs with a pseudoacetabulum was more challenging than in control dogs. However, the procedure provided good to excellent long-term clinical outcomes in all dogs. CLINICAL SIGNIFICANCE: Surgeons should be prepared for the specific surgical challenges associated with THA in dogs with pseudoacetabulum formation.

Correlation of distraction index with arthroscopic findings in juvenile dogs with hip dysplasia.

OBJECTIVE: To compare distraction index (DI) with hip arthroscopy findings in juvenile dogs with hip dysplasia undergoing unilateral or bilateral double pelvic osteotomy (DPO). STUDY DESIGN: Retrospective case series. ANIMALS: Twenty dogs (36 hip joints). METHODS: Medical records from dogs undergoing unilateral or bilateral DPO (2011-2016) were reviewed. Distraction index was measured by using distraction view radiographs. Arthroscopic images were analyzed. Cartilage was graded by using the modified Outerbridge scale (0 = arthroscopically normal, 1 = chondromalacia, 2 = surface fibrillation, 3 = deep fissuring, 4 = full-thickness cartilage loss, and 5 = eburnation of exposed subchondral bone). Dorsal acetabular rim, acetabular labrum, the ligament of head of the femur, and synovitis were graded by using a four-point scale (normal, mild, moderate, severe). Spearman and Pearson correlations were used to compare DI between grade groups and age. RESULTS: Distraction index ranged from 0.4 to 1.0 (mean 0.69 ± 0.16). Most of the hips had an arthroscopically normal femoral head and acetabulum in most regions, except for the region at the insertion of the ligament of the head of the femur. There was a low positive correlation between synovitis and DI (Spearman ρ = 0.35, P = .0346). No other differences in DI were identified between grade or age groups. CONCLUSION: There was a low positive correlation between synovitis and DI. No other differences in DI were identified. CLINICAL SIGNIFICANCE: Arthroscopic evaluation of the coxofemoral joint prior to DPO can allow detection of joint pathology that might not be appreciated by using traditional radiographic screening criteria.

Management of total hip replacement luxation with triple pelvic osteotomy.

OBJECTIVE: To report the outcome of dogs treated with triple pelvic osteotomy (TPO) for dorsal luxation after total hip replacement (THR). STUDY DESIGN: Retrospective clinical case series. ANIMALS: Seventeen client-owned animals. METHODS: Medical records were searched at a single institution for dogs that had been treated with TPO for dorsal THR luxation. The angle of lateral opening (ALO), version angle (VA), and inclination angle (IA) were measured from radiographs after THR and TPO and corrected for pelvic rotation. A paired t test was performed to compare cup orientation after THR and TPO. Functional outcome was assessed at follow-up examination and during telephone interviews. RESULTS: Eighteen TPOs were performed in 17 dogs, and radiographs were available for 15 cases. Open and/or closed hip reduction with additional stabilization was attempted unsuccessfully in 6 dogs prior to TPO. Triple pelvic osteotomy reduced the ALO by a mean of 23.0 ° ± 10.9 ° (P ≤ .001), increased VA by 9.0 ° ± 4.9 ° (P < .001), and increased IA by 2.9 ° ± 5.8 ° (P = .126). An excellent or good outcome was achieved in 12 dogs. Ventral luxation occurred in 3 dogs, and dorsal luxation occurred in 1 dog after TPO. Triple pelvic osteotomy excessively reduced ALO in 2 dogs with ventral luxation. CONCLUSION: Triple pelvic osteotomy with cup retention is a viable alternative to cup revision for treatment of dorsal luxation of cemented and cementless THR. Triple pelvic osteotomy significantly reduces ALO and increases VA. Careful patient selection is recommended because excessive ventroversion can lead to ventral luxation. CLINICAL SIGNIFICANCE: Triple pelvic osteotomy offers a revision option that preserves the implant-bone interface and significantly reduces ALO. This technique may be appropriate in dogs with high ALO, luxoid hips, and prior failed revision attempts.

Comparison of Rotation Force to Maintain Acetabular Ventroversion after Double Pelvic Osteotomy and 2.5 Pelvic Osteotomy in a Canine Cadaveric Model.

OBJECTIVE: The aim of this article was to compare the force required to maintain the acetabular ventroversion after double pelvic osteotomy (DPO) and modified triple pelvic osteotomy (2.5PO). METHODS: Unilateral DPO (group A) and unilateral modified DPO (group B = 2.5PO) were performed on cadaveric canine pelves (n = 10/group). The twisting moment required to maintain fragment position for DPO and 2.5DPO was compared. RESULTS: Mean twisting moment for the DPO group [5.92 N/m ± 2.59 (range, 2.61-12.17 N/m)] and the 2.5PO group [2.11 N/m ± 0.93 (range, 0.63 -3.85 N/m)] was significantly different (p < 0.01). CONCLUSION: Dorsal cortex osteotomy of the ischium decreases the acetabular segment rotation force. Decreased force may facilitate acetabular rotation during DPO procedure.

A structural numerical model for the optimization of double pelvic osteotomy in the early treatment of canine hip dysplasia.

BACKGROUND: Double pelvic osteotomy (DPO) planning is usually performed by hip palpation, and on radiographic images which give a poor representation of the complex three-dimensional manoeuvre required during surgery. Furthermore, bone strains which play a crucial role cannot be foreseen. OBJECTIVE: To support surgeons and designers with biomechanical guidelines through a virtual model that would provide bone stress and strain, required moments, and three-dimensional measurements. METHODS: A multibody numerical model for kinematic analyses has been coupled to a finite element model for stress/strain analysis on deformable bodies. The model was parametrized by the fixation plate angle, the iliac osteotomy angle, and the plate offset in ventro-dorsal direction. Model outputs were: acetabular ventro-version (VV) and lateralization (L), Norberg (NA) and dorsal acetabular rim (DAR) angles, the percentage of acetabular coverage (PC), the peak bone stress, and moments required to deform the pelvis. RESULTS: Over 150 combinations of cited parameters and their respective outcome were analysed. Curves reporting NA and PC versus VV were traced for the given patient. The optimal VV range in relation to NA and PC limits was established. The 25° DPO plate results were the most similar to 20° TPO. The output L grew for positive iliac osteotomy inclinations. The 15° DPO plate was critical in relation to DAR, while very large VV could lead to bone failure. CLINICAL SIGNIFICANCE: Structural models can be a support to the study and optimization of DPO as they allow for foreseeing geometrical and structural outcomes of surgical choices.

Conservative Management of Hip Dysplasia.

Hip dysplasia (HD) is a common orthopedic condition seen in small animal patients that leads to osteoarthritis of the coxofemoral joint. The disease can be managed conservatively or surgically. The goals of surgical treatment in the immature patient are to either prevent the clinical signs of HD or to prevent or slow the progression of osteoarthritis. In mature patients surgery is used as a salvage procedure to treat debilitating osteoarthritis. Conservative management can be used in dogs with mild or intermittent clinical signs and includes nutritional management and weight control, exercise modification, physical rehabilitation, pain management and disease-modifying agents.

Physical Rehabilitation for the Management of Canine Hip Dysplasia.

Hip dysplasia is among the most common orthopedic conditions affecting dogs. Joint laxity is responsible for abnormal development of the femoral head and acetabulum, leading to excessive wear of the articular cartilage. Wear leads to secondary osteoarthritis. Rehabilitation is either conservative or after surgical management. Conservative rehabilitation therapies are directed at decreasing pain, improving hip range of motion (ROM), and building or maintaining muscle mass. Postoperatively, rehabilitation focuses on decreasing postoperative pain and inflammation, improving comfort and limb use, and protecting the surgical site. Once the patient has healed, rehabilitation is directed at improving ROM and promoting muscle mass.

Juvenile Pubic Symphysiodesis.

In properly selected dogs, juvenile pubic symphysiodesis improves joint congruity, decreases hip laxity, and can reverse or prevent progression of degenerative joint disease in the hips. To be effective, surgery must be done at a young age and in hips that are only mildly to moderately lax. Juvenile pubic symphysiodesis is best viewed more as a preemptive procedure than as a strictly therapeutic one. Dogs considered to be at risk for hip dysplasia should be screened with Ortolani testing at 12 weeks of age, with further imaging and perhaps surgery to follow for those who have a positive Ortolani sign.

Femoral Head and Neck Excision.

Femoral head and neck excision is a surgical procedure that is commonly performed in small animal patients. It is a salvage procedure that is done to relieve pain in the coxofemoral joint and restore acceptable function of the limb. Femoral head and neck excision is most commonly used to treat severe osteoarthritis in the coxofemoral joint and can be done in dogs and cats of any size or age. The procedure should not be overused and ideally should not be done when the integrity of the coxofemoral joint can be restored.

INNOPLANT Total Hip Replacement System.

Total hip replacement is a salvage procedure that is done to alleviate discomfort secondary to osteoarthritis in the hip, which is most often a result of hip dysplasia. Commercially available total hip replacement implants for small animal patients are classified as cemented or cementless. The INNOPLANT Total Hip Replacement system includes modular, screw-in cementless components that were developed to improve implant stability by maintaining as much normal anatomic structure, and by extension biomechanics of the coxofemoral joint, as possible. As a newer system, there are few data and no long-term studies available in the veterinary literature.

Triple Pelvic Osteotomy and Double Pelvic Osteotomy.

Triple and double pelvic osteotomy (TPO, DPO) are performed with the goal of increasing acetabular ventro-version, increasing femoral head coverage, and decreasing femoral head subluxation. Since the first descriptions of TPO, there have been modifications in technique, most notably omission of the ischial osteotomy for DPO, and improvements in the implants, including availability of locking TPO/DPO bone plates. Associated complication rates seem to have declined accordingly. The most salient questions regarding these procedures remain what selection criteria should be used to identify candidates and whether halting or preventing osteoarthritis is necessary to consider these surgeries clinically beneficial.

Zurich Cementless Total Hip Replacement.

Total hip replacement (THR) is the gold standard treatment of intractable pain from hip dysplasia. THR procedures are divided into 2 main categories: cemented and cementless, with hybrid a combination. The Zurich Cementless THR system uses a combination of press-fit (acetabular component) and locking screw (femoral component) fixation designed to address the main challenge facing cemented systems (aseptic loosening) while providing the benefit of immediate stability with its novel locking screw implantation system for the femoral stem. The Zurich THR system is an effective treatment option for orthopedic conditions of the coxofemoral joint in medium to giant breed dogs.

Avaliação radiográfica e tomográfica de cães submetidos à artroplastia coxofemoral total híbrida / Radiographic and tomographic evaluation of total hybrid hip replacement in dogs

A artroplastia total da articulação coxofemoral é a técnica cirúrgica mais efetiva para o tratamento da displasia coxofemoral canina grave. Na atualidade, o exame radiográfico é o método mais utilizado para se avaliar esse procedimento em cães, porém possui algumas limitações. Já o exame tomográfico por meio de tomografia computadorizada possibilita a aquisição de imagens sem sobreposições e, dessa forma, a determinação do posicionamento dos componentes protéticos com maior precisão. A presente pesquisa teve como objetivo avaliar, por meio de exames radiográficos e tomográficos, a utilização de uma prótese total modular híbrida da articulação coxofemoral desenvolvida e confeccionada no Brasil, aplicada experimentalmente em cães sadios. Foram utilizados seis cães esqueleticamente maduros, previamente submetidos ao procedimento cirúrgico da articulação coxofemoral esquerda. Os cães foram submetidos ao exame tomográfico aos 360 dias e três anos após a cirurgia. Todos os animais apresentaram bom posicionamento dos componentes protéticos e redução articular adequada. Ao exame tomográfico, entretanto, foram detectadas áreas de preenchimento irregular em alguns animais. Adicionalmente, o exame tomográfico permitiu a detecção e monitoração de áreas de reabsorção óssea ao redor do componente acetabular. Assim, o exame tomográfico mostrou-se útil na avaliação das articulações protéticas, com a vantagem de apresentar ótima definição das imagens e permitir quantificar alterações periprotéticas e mensurar relações articulares, fundamentais para o acompanhamento pós-cirúrgico tardio.(AU)

The total hip arthroplasty is the most effective surgical technique for the treatment of severe canine hip dysplasia. Currently, the radiographic examination is the most common method used to assess this procedure in dogs, but has some limitations. CT scan by computed tomography instead enables the acquisition of images without overlap, thereby determining the positioning of prosthetic components with greater accuracy. This research aimed to evaluate by radiography and CT scan examinations the use of a hybrid modular total hip prosthesis developed and made in Brazil, applied experimentally in healthy dogs. Six skeletally mature dogs, which previously underwent surgery on the left hip joint were used. The dogs underwent CT scan at 360 days and three years after surgery. All animals showed good positioning of prosthetic components, and proper joint reduction. In the CT scan, however, it was possible to detect irregular fill areas in some animals. In addition, CT scan allowed the detection and monitoring of areas of bone resorption around the acetabular component. Therefore, the CT scan was useful in the evaluation of prosthetic joints, with the advantage of optimum sharpness of the images and allowing for the possibility of quantifying peri-prosthetic changes and measure joint, fundamental relations for late postoperative follow-up.(AU)

Cementless total hip replacement in 20 juveniles using BFX™ arthroplasty.

OBJECTIVE: To describe outcome after a minimum of 1 year for total hip replacement (THR) using BioMedtrix BFX™ biologic fixation implants in skeletally immature dogs (6-10 months of age). STUDY DESIGN: Case series. ANIMALS: Dogs (n = 20). METHODS: Medical records (November 2007-June 2010) of 20 dogs, 6-10 months old that had cementless THR were reviewed. Preoperative, immediate, 6-week and >1-year postoperative radiographs were compared. Clinical examination was performed at 6 weeks and >1 year postoperatively. Owner questionnaire was obtained at final follow-up. RESULTS: Cementless THR using BFX™ implants was performed because of debilitating coxofemoral pain, resulting from canine hip dysplasia, after unsatisfactory outcome with medical management. Radiographs taken immediately, 6 weeks and at a mean of 29.8 months (range, 12-48 months) postoperatively revealed satisfactory implant positioning and stability. Significant change in measured cranial-caudal femoral stem fill and level (P < .001 and P = .006, respectively) were recorded at 6 weeks postoperatively without clinical significance. No further change in stem positioning occurred. Acetabular cup orientation remained unchanged throughout follow-up. Complications requiring further surgical intervention were not encountered. One minor superficial infection was recorded and treated. Lameness and pain on manipulation of the affected hip had greatly improved in all dogs by 6 weeks postoperatively. CONCLUSION: Cementless THR can safely be performed in skeletally immature dogs, providing satisfactory return to normal joint function and implant survivability for at least a mean of 29.8 months.

Estudio de los efectos de las lesiones del labrum acetabular en la cadera en un modelo experimental lagomorfo adulto / Study of the effects of the hip acetabular labrum damage in a rabbit animal model

Objetivo: El cartílago labral es una estructura cartilaginosa que recubre el acetábulo de la cadera. Su lesión es controvertida en cuanto a sus implicaciones debido a que no se conoce bien si es una causa de degeneración articular o sólo un cambio degenerativo más. Hemos diseñado un modelo animal en conejo para estudiar esta lesión. Material y metodología: Se utilizaron tres grupos de 13 animales a los que se lesionó una cadera dejando la otra como control y se les mantuvo estabulados al primer grupo 12 semanas, al segundo 18 y al tercero 30. Posteriormente se les realizó un estudio radiológico, otro por resonancia magnética y, tras su sacrificio, un estudio histológico. Resultados: No encontramos relación en nuestro modelo entre la lesión labral y los cambios degenerativos posteriores en los plazos citados. Tampoco encontramos daños labrales sin cicatrizar en el momento del sacrificio. Conclusión: En el modelo animal lagomorfo, la lesión labral no produce cambios degenerativos artrósicos y el cartílago labral podría presentar cierta capacidad de regeneración (AU)

Objective: The labrum is a cartilaginous structure that covers the hip acetabulum. The labral lesions are controverted because it is not known if the labral tears are a cause or a consequence of the hip osteoarthrosis. Material and methods: We designed a rabbit animal model to study the labral tears. We used three groups of 13 animals. We injured the labral cartilage of every rabbit in the right hip, and we used the left hip as a control. The animals were kept alive for 12, 18 and 30 weeks. We realized a radiologic, a magnetic resonance and a histological study in every rabbit to see the labral tears consequences. Results: We did not found in our model any significant relationship between the labral tears and the secondary osteoarthrosis in the studied time. We didn't found labral damage without heal when the animals were sacrificed. Conclusion: We can conclude, in the rabbit animal model, the labral tears don't produce degenerative changes in the hip. The labrum have regenerative capacity in the rabbit animal model (AU)