Preliminary results of five feline total hip replacements

Stabilisation of femoral capital physeal fractures using transcervical pinning in cats: 19 cases (2014-2022)

OBJECTIVES

To report the short-term clinical and radiographic outcomes in cats with femoral capital physeal fractures stabilised with transcervical pinning.

MATERIALS AND METHODS

Medical records of cats diagnosed with femoral capital physeal fractures and treated with transcervical pinning were reviewed. The collected data included signalment, weight, time from lameness to surgery, reported trauma, affected side, concomitant orthopaedic injuries, radiographs, osteoarthritis, femoral neck osteolysis, proximal femoral epiphysis to femoral neck ratio, fracture reduction, implants, complications and clinical evaluation results. An owner questionnaire was used for long-term follow-up.

RESULTS

Nineteen cats with a total of 21 fractures met the inclusion criteria. Fifteen of the 19 cats showed no signs of lameness at the 1-month follow-up. Major and catastrophic complications occurred in 9.5% and 23.8% of the fractures, respectively. All catastrophic complications occurred in fractures with a high preoperative osteolysis grade (2 or 3).

CLINICAL SIGNIFICANCE

In our study, transcervical pinning was found to be a reliable fixation method for the treatment of femoral capital physeal fractures in cats with minimal preoperative femoral neck osteolysis. High rates of implant failure with loss of fracture reduction were observed in cats with high-grade preoperative osteolysis.

Short-Term Clinical and Radiographic Outcome after Stabilization of Femoral Capital Physeal Fractures with Cortical Positional Screws in 39 Cats

OBJECTIVE

 The aim of this study was to report the short-term clinical and radiographic outcome for the treatment of femoral capital physeal fractures with cortical positional screws in cats.

STUDY DESIGN

 Medical records and radiographs of cats with femoral capital physeal fractures stabilized with cortical positional screws were retrospectively reviewed. Signalment, bodyweight, femoral head affected, fracture classification, fracture reduction, implants, concurrent orthopaedic injuries, osteoarthritis, femoral neck osteolysis, complications and 6-week follow-up clinical results were recorded. A short- to long-term follow-up was performed by telephone questionnaire with the owners.

RESULTS

 Forty-six fractures in 39 cats met the inclusion criteria. In 45/46 fractures, radiographic signs of bone healing were present and 35/39 cats were assessed as walking normally by a veterinarian at 6-week follow-up. There was a significant increase in radiographic signs of osteoarthritis (p=0.037) and femoral neck osteolysis (p=0.001) on 6-week follow-up radiographs. Pre- and postoperative osteoarthritis and femoral neck osteolysis were not associated with clinical outcome. The mean follow-up period for the telephone questionnaire was 48 months (range, 5-147 months). Seven out of 25 owners reported a gait abnormality in the short- to long-term.

CONCLUSION

 Femoral capital physeal fractures in cats can be treated successfully with the use of cortical positional screws. This technique may be considered as an alternative to other primary fixation techniques and salvage procedures for the treatment of femoral capital physeal injuries in cats. This technique seemed successful in cats with a low-grade preoperative femoral neck osteolysis.

Feline Femoral Fracture Fixation: What are the options?

PRACTICAL RELEVANCE

The femur is the most commonly fractured bone in cats. Femoral fractures usually result from high-velocity trauma such as a road traffic accident or fall from a height and, as such, are associated with a wide variety of concurrent injuries. The initial focus of treatment should always be on assessment and stabilisation of the major body systems. Once any concurrent injuries have been addressed, all femoral fractures need surgical stabilisation, with the notable exception of greenstick fractures in very young cats, which can heal with cage rest alone. A number of different surgical options are available depending on the fracture type, location, equipment, surgeon experience and owner finances.

CLINICAL CHALLENGES

Femoral fractures can vary hugely in complexity and the small size of feline bones can limit the choice of implants. Furthermore, cats can present unique challenges in the postoperative period due to their active nature and the limited means to control their exercise level.

AUDIENCE

This review is aimed at general and feline-specific practitioners who have some experience of feline orthopaedics, as well as those simply wishing to expand their knowledge.

AIMS

The aim of this review is to help clinicians assess, plan and manage feline femoral fractures. It provides an overview of diagnostic imaging and a discussion of a range of suitable surgical options, including the principles of different types of fixation. It also highlights cat-specific issues, approaches and implants pertinent to the management of these cases.

EVIDENCE BASE

A number of original articles and textbook chapters covering many aspects of femoral fractures in cats and dogs have been published. Where possible, this review draws on information from key feline research and, where necessary, extrapolates from relevant canine literature. The authors also offer practical guidance based on their own clinical experience.

Measurement of ground reaction forces in cats 1 year after femoral head and neck ostectomy

OBJECTIVES

The objective of this study was to compare ground reaction forces (GRFs) of a group of cats after femoral head and neck ostectomy (FHO) with those of a historical control group.

METHODS

We searched the database of the Small Animal Clinic of the Veterinary University in Vienna for cats that had undergone unilateral FHO at least 1 year previously. Owners were telephoned and invited to the clinic with their cats for a re-examination. An in-house owner questionnaire-based evaluation, complete orthopaedic examination, hip radiography and gait analysis with a pressure-sensitive plate were performed, and results were compared within and between groups (FHO group and control group [CG]).

RESULTS

Seventeen cats that had undergone FHO (FHO group) at least 1 year previously and 15 healthy cats (CG) from a previous study were included. Measured GRFs (peak vertical force and vertical impulse [IFz] normalised to total force [%TF]) of the FHO legs were lower than those of the other legs of the FHO group and the legs of the CG. Results of the owner questionnaire were generally good and did not match the results of the GRF comparison. Furthermore, the gaits evaluated during the orthopaedic examination did not correlate with the measured GRFs where we identified a certain degree of lameness (reduced IFz, %TF) in all cats. Cats with limb shortening (dorsally displaced major trochanter major) were not revealed to have different GRF measurements.

CONCLUSIONS AND RELEVANCE

This is the first study to assess GRFs in a large group of cats that had undergone FHO, comparing findings with those in healthy cats. Even if the differences are statistically significant, but rather small, our findings point to a long-term residual gait abnormality that could be detected using a pressure-sensitive plate but not always with an orthopaedic examination, in cats 1 year after FHO.

Zürich cementless total hip arthroplasty as a treatment option for capital physeal fractures in dogs: Outcome in 53 cases

OBJECTIVE

To review the outcome of dogs that underwent Zürich cementless total hip arthroplasty (Z-THA) for the repair of acute and chronic capital physeal fractures (CPF) and document the CPF-related hip remodeling.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Fifty-three Z-THA in 53 dogs.

METHODS

Medical records of dogs (2006-2019) that underwent Z-THA for CPF management were reviewed. Dogs were divided into two groups on the basis of the days elapsed between CPF diagnosis and Z-THA, acute (≤30 days) and chronic (>30 days). Hip remodeling variables were determined from preoperative radiographs or intraoperatively. Descriptive statistics were performed, and the complication rates, outcome, and coxofemoral remodeling were recorded. Comparisons of remodeling variables and rates between groups were performed by using Fisher's exact test.

RESULTS

In total, 23 of 53 (43.4%) cases were acute, and 30 of 53 (56.6%) cases were chronic. There was no difference in the femoral remodeling rates between the acute and chronic groups (P = .184), whereas acetabular remodeling was more prevalent in the chronic group (P < .001). Intraoperative complications occurred in four of 53 (7.5% [1/23 acute, 3/30 chronic]) cases, and postoperative complications occurred in six of 53 (11.3% [2/23 acute, 4/30 chronic]) cases. Good clinical outcomes were achieved in 51 of 53 (96.2% [21 acute, 30 chronic]) cases.

CONCLUSION

Complication rates of Z-THA for CPF repair were similar to the complication rates reported for Z-THA of dysplastic hips. Hip remodeling was common regardless of CPF chronicity.

CLINICAL SIGNIFICANCE

Zürich cementless total hip arthroplasty is viable for surgical management of CPF. There is a high likelihood that hip remodeling will be encountered, even in fractures treated within 30 days of presenting for hind limb lameness.

Traumatic joint luxations in cats: Reduce, repair, replace, remove

PRACTICAL RELEVANCE

Traumatic joint luxations are usually associated with significant trauma and there may be concomitant systemic injury. Joints are unstable as a result of injury to one or more supporting structures and the clinician should aim to determine which structures are damaged with physical examination, diagnostic imaging and careful assessment under sedation/anaesthesia. The aim is to reduce the joint back to its anatomical position, and then to maintain this through repair of damaged structures. However, where this is not possible, replacement or removal (arthrodesis/excision arthroplasty) of the joint remain viable options.

CLINICAL CHALLENGES

Owing to the small size of feline joints and the severity of damage often seen, surgical management of these cases can be challenging. The first priority is to ensure the patient is systemically well before embarking on any specific surgical treatment of a luxated joint. Cats also present challenges in the postoperative period and a lack of patient and owner compliance can be detrimental to postoperative outcomes.

AIMS

This article aims to help the reader diagnose joint luxations and to assist decision-making with an overview of the management and treatment options available.

EVIDENCE BASE

There are a number of original articles and textbook chapters in the literature covering aspects of different joint luxations, particularly for the more common luxations. This article draws on information from key feline research and, where necessary, extrapolates from relevant canine research. The authors also offer practical guidance based on their own clinical experience.

Morphometric assessment of hip dysplasia in a cat treated by juvenile pubic symphysiodesis

Objective: To quantitatively evaluate the change of the coxofemoral joints using computed tomography and distraction index in a cat with hip dysplasia treated by juvenile pubic symphysiodesis.

Study Design: Case report.

Animal: Eighteen-week-old female entire Maine Coon cat.

Results: Juvenile pubic symphysiodesis resulted in changes in the distraction index, acetabular angle, dorsal acetabular rim angle, dorsal acetabular sector angle, and clinical improvement at the six month follow-up. No intra-operative or postoperative complications were recorded.

Conclusions: Juvenile pubic symphysiodesis performed at 18 weeks of age resulted in improvement in hip joint conformation and hip laxity in a dysplastic cat.

Clinical relevance: Juvenile pubic symphysiodesis may be a promising treatment for feline hip dysplasia and is a safe and technically simple procedure to perform. Further investigations are warranted.

Slipped capital femoral epiphysis in 17 Maine Coon cats

Objectives

From May 2009 to January 2015, 208 Maine Coon cats presented to the Tierklinik Hollabrunn – a small animal referral and first-opinion centre – and 17 (8.17%) cats were diagnosed with a slipped capital femoral epiphysis (SCFE). Over the same time period, 29 (0.67%) of 4348 cats (all breeds) were diagnosed with SCFE.

Methods

Clinical and orthopaedic examinations and diagnostic imaging were performed on all affected Maine Coons. Age at first presentation, sex, body weight, body condition score (BCS), unilateral or bilateral manifestation of the disease, activity level and duration of lameness, age at neutering and known family history of disease were recorded. Sixteen of 17 Maine Coons were surgically treated. Surgically removed femoral tissue samples were histologically examined in 13 cases.

Results

The mean age at first presentation was 21.47 months; male to female ratio was 16:1; mean body weight was 7.5 kg (range 5.3–9.3 kg); and mean BCS was 5.06/9.0. Seven cats were bilaterally affected; the median duration of decreased activity level and lameness was 2 weeks; mean age at neutering was 7.7 months (range 3.0–12.0 months); and four cats were littermates. Fourteen femoral head and neck ostectomies, eight total hip replacements and one primary fixation were performed. All 13 histologically available samples confirmed the diagnosis of SCFE.

Conclusions and relevance

To date, SCFE has been reported only occasionally in Maine Coon cats. However, the results of this study showed that Maine Coons were approximately 12-fold more likely to develop SCFE than the overall population of cats presenting to the Tierklinik Hollabrunn over the same time period. Male sex, neutering, delayed physeal closure and breed-specific high body weight may play an important role in the pathogenesis of SCFE in Maine Coon cats.

Feline hip dysplasia

Practical relevance:

The reported incidence of hip dysplasia (HD) in cats varies dramatically between studies, but the condition is likely more common than we realise. There is little doubt that cats with HD and associated osteoarthritis (OA) suffer pain, and this warrants appropriate therapy.

Diagnostic challenges:

Clinical signs of HD in cats are often gradual in onset, making them difficult to appreciate, but may include inactivity, pelvic limb lameness, difficulty jumping and climbing stairs, and reluctance to squat to defecate. Often lameness is bilateral, and can be particularly difficult to recognise. The most common radiographic finding is an abnormally shallow acetabulum. Subluxation, however, is not consistently associated with OA in cats and therefore the role that joint laxity plays in disease progression remains uncertain. Degenerative changes of the femoral head and neck seem to develop later than in the dog, and are less marked.

Therapeutic challenges:

The majority of cats respond to non-surgical management with environmental modulation, physical therapy, dietary modulation, weight loss, nutraceuticals and drug therapy. Should non-surgical management not provide sufficient relief, two salvage surgical options are available: femoral head and neck excision (FHNE) and total hip replacement (THR). While there is a risk of complications with micro-THR, the positive outcomes that have been reported indicate that it should be considered in the treatment of coxofemoral pathology in cats in the same way that THR is considered for larger dogs, especially given the inconsistent results associated with FHNE. Monitoring the effect of treatment is challenging as the assessment of pain in cats is complex and there is no validated scoring system or owner-completed questionnaire yet available for cats.

Evidence base:

There is a paucity of clinical reports focusing solely on HD in cats. The author draws on a combination of published studies, in cats, dogs and humans, as well as personal clinical experience.

Femoral head and neck excision in cats: medium- to long-term functional outcome in 18 cats

Objective

To assess the medium- to long-term functional outcome of cats after femoral head and neck excision (FHNE) using an owner-completed questionnaire.

Methods

Cats that had FHNE and were free of other orthopaedic or medical conditions that could affect their mobility, other than the studied coxofemoral joint(s), were included. A specific owner-completed questionnaire was used at a minimum of 4 months postoperatively. The questionnaire assessed the ability of the cats to perform normal feline activities, change of demeanour or behaviour, the necessity for long-term analgesia and the time taken to resume normal activities.

Results

Eighteen cats had undergone uni- or bilateral FHNE and met the inclusion criteria. All but one cat could perform normal feline activities without or with slight difficulty at follow-up. The aforementioned cat had notable, persistent difficulty in climbing. The majority of the cats took between 1 and 2 months to resume normal activity. No change in demeanour or behaviour was noted in any of the cats and none of the cats required long-term analgesia.

Conclusions and relevance

Based on the owner-completed questionnaire, cats have good-to-excellent medium- to long-term functional outcome after adequately performed FHNE.

Advances in total joint replacement in small animals

Total joint replacement is now considered a routine surgical option for small animals with advanced joint disease. This review highlights the current state of the art in total hip, elbow and knee replacement in small animals, as well as the potential for application to other joints such as the intervertebral discs, hock and shoulder. Advances in cementless fixation, the use of less-invasive, bone-sparing procedures, and the development of custom implant options for revision surgery and oncologic reconstruction will be discussed. As growth in this field continues, it is important that future developments in total joint replacement are built on a foundation of detailed laboratory evaluation of new implant designs and surgical techniques, objective assessment of clinical outcomes, and a comprehensive, coordinated retrieval program that evaluates both well-functioning and failed joint replacements.