Histomorphometric analysis of the proximal portion of the femur in dogs with osteoarthritis

OBJECTIVE: To describe cancellous architecture of the proximal portion of the femur in dogs with osteoarthritis. ANIMALS: 30 dogs with coxofemoral osteoarthritis. PROCEDURE: All dogs had femoral head and neck excision or total hip arthroplasty. Histomorphometry software was used to analyze computer images of 100-microm-thick coronal and transverse plane sections of the head and neck of the femur. Histologic preparations of coronal and transverse sections of articular cartilage were graded. RESULTS: Bone volume/total volume, trabecular thickness, trabecular number, and bone surface/total volume were significantly higher in the femoral head than femoral neck. Trabecular alignment (anisotropy) and separation were significantly higher in the femoral neck than femoral head. Anisotropy was significantly increased in the medial portion of the femoral head in the coronal plane and in the cranial portion of the femoral neck in the transverse plane, compared with healthy dogs. The medial half of femoral head cartilage that overlies the proximomedial cancellous bone region had significantly more degraded cartilage than the lateral half. Histologic grades for cranial and caudal halves of femoral head articular cartilage were similar. CONCLUSIONS AND CLINICAL RELEVANCE: Most findings were similar to those in healthy dogs. Greater trabecular alignment in the proximomedial region of the femoral head and craniolateral region of the femoral neck in dogs with osteoarthritis suggests an altered transfer of load through the coxofemoral joint. Greater cartilage degradation on the medial half of the femoral head supports an association between increased trabecular alignment and cartilage degradation.     

Long term follow-up of avascular necrosis of the femoral head in the dog

In a clinical study of 35 dogs with avascular necrosis of the femoral head, 60 per cent were Yorkshire terriers; the mean age of 33 of the dogs at onset of clinical signs was seven months. The dogs had the following signs: muscle atrophy (n = 25), shortening of the affected leg (n = 14), pain on passive movement of the hip joint (n = 28), and crepitation of the hip joint (n = 8). Radiographic findings were irregular density and flattening of the femoral head in combination with degenerative joint disease. Conservative treatment consisted of exercise therapy, and surgical treatment of a standard femoral head and neck excision. In 17 of the dogs the results of therapy were evaluated with the help of a questionnaire. It is concluded that femoral head and neck excision is indicated when conservative treatment fails to lead to clinical improvement within four weeks. Femoral head and neck excision has a good long term prognosis; however, slight intermittent lameness may remain.     

Magnetic resonance imaging of the femoral head of normal dogs and dogs with avascular necrosis.

The purpose of this study was to describe the appearance of the femoral head of normal, young, small breed dogs, and dogs with avascular necrosis using low-field (0.3 T) magnetic resonance (MR) imaging. Images of the femoral heads were obtained in the dorsal plane, and included T1-weighted spin-echo, T2-weighted fast spin-echo, fast spin echo-inversion recovery, and fluid attenuated inversion recovery pulse sequences. MR imaging features of the asymptomatic femoral heads and necks included uniform high signal intensity compared with muscle on T1- and T2-weighted images. There was either uniform enhancement or no enhancement on postcontrast T1-weighted images. The MR imaging findings of dogs affected with avascular necrosis differed from those of asymptomatic dogs. Typically, the affected dogs had inhomogeneous intermediate to low-signal intensity within the femoral head and neck compared with muscle on T1-weighted images, inhomogeneous enhancement of the femoral head and/or neck on postcontrast T1-weighted images, and inhomogeneous low- to high- signal intensity within the femoral head and neck on T2-weighted images.     

A Comparison of Standard Femoral Head and Neck Excision and Femoral Head and Neck Excision Using a Biceps Femoris Muscle Flap in the Dog

Sixteen normal 20 to 30 kg dogs had standard femoral head and neck excision (8 dogs) or femoral head and neck excision with interposition of a biceps muscle flap (8 dogs). Lameness lessened at week 6, and did not differ between groups; neither group returned to a completely normal gait. Weightbearing decreased on the operated pelvic limb compared to controls (forceplate analysis). Weightbearing force of the muscle flap dogs was significantly less at weeks 6 and 16 than that of the standard femoral head and neck excision dogs. The operated limb of both groups was shortened; shortening was significantly greater for the muscle flap group. Hip extension was limited in both groups. Both groups had decreased (more acute) hip, stifle, and hock angles measured in standing position. Thigh muscle atrophy was more pronounced in the muscle flap group at week 6. More soft tissue was interposed in the muscle flap group at necropsy compared to the group with standard femoral head and neck excision, but the difference was not statistically significant. Skeletal muscle fibers were present in the interposed fibrous connective tissue of the muscle flap group, and the healed surfaces were smoother than those of the standard femoral head and neck excision group.     

Histomorphometric analysis of the proximal portion of the femur in healthy dogs

OBJECTIVE: To describe the cancellous bone architecture of the head and neck of the femur in healthy dogs by use of automated histomorphometry techniques in conjunction with histologic grading of articular cartilage. ANIMALS: 30 mature male dogs with healthy coxo-femoral joints PROCEDURE: Dogs were 1.5 to 4 years old and weighed 27 to 37 kg. Computer images of fine-detail radiographs of 100-microm-thick coronal and transverse plane sections of the head and neck of the femur (14 dogs) were analyzed by use of histomorphometry software. Statistical comparisons among histomorphometric indices of 4 regions were performed. Histologic preparations of coronal and transverse plane sections of femoral head articular cartilage (16 dogs) were graded. Median grades for lateral, medial, cranial, and caudal halves of the femoral head articular cartilage were determined. RESULTS: Bone volume/total volume, trabecular thickness and number, and bone surface/total volume were significantly higher in the femoral head than in the femoral neck. Anisotropy (trabecular alignment) and trabecular separation were significantly higher in the femoral neck than in the femoral head. Anisotropy was significantly higher in the caudal half of the femoral neck than in the cranial half. Cartilage had histologic grades indicating health without significant differences among lateral, medial, cranial, and caudal halves of femoral head cartilage. CONCLUSIONS AND CLINICAL RELEVANCE: A predictable cancellous architecture in the head and neck of the femur is associated with healthy cartilage.     

Effect of triple pelvic osteotomy on the proximal femoral geometry in dysplastic dogs

Triple pelvic osteotomy (TPO) is one of the surgical procedures for use to try to reduce subsequent degenerative joint disease or modify the progress of hip dysplasia in young dogs. Joint force and pressure distribution were changed by this procedure. Therefore, the aim of this study was to find out whether the remodeling of proximal femur exists or not after TPO in dysplastic dogs. Ten femora from five young dysplastic mongrel dogs, treated unilaterally with TPO using 20° canine pelvic osteotomy plates, were used. One year after TPO, neck-proximal shaft angle, femoral head, neck, diaphyseal and mid-shaft diameters, total femoral, femoral neck axis, and intertrochanteric, femoral head offset lengths as well as the lengths from head center to lateral margin of greater trochanter and to proximal femoral axis were measured from the bone. The significant differences between treatment and control side were determined in Norberg angle, neck-proximal shaft angle, neck diameter, diaphyseal diameter, mid-shaft diameter, length from head center to proximal femoral axis and femoral head offset length. In conclusion, although small number of cases was used, it was determined that the aforementioned variables are affected by TPO. So, these variables may be supply additional information about the changes to the joint following TPO in dysplastic dogs.     

Histomorphometric analysis of the proximal portion of the femur in dogs with moderate osteoarthritis

OBJECTIVE: To describe the histomorphometric properties of epiphyseal and metaphyseal trabecular bone of the proximal portion of the femur of dogs with moderate osteoarthritis. SAMPLE POPULATION: Proximal portions of a femour from 24 dogs. PROCEDURE: The proximal portion of a femur was obtained from each dog. Eleven and thirteen specimens were sectioned in the transverse and coronal planes, respectively. Three evenly spaced sections from each specimen were chosen, surface stained, and digitized, and the stained areas were preferentially selected. Custom software was used for histomorphometric analysis of each section. A mixed-model analysis was used to evaluate the effect of slice location and region on 6 parameters, and a Fisher protected t test was used when differences were detected. RESULTS: There was a significant difference between the femoral head and femoral neck for all parameters tested. In coronal sections, the femoral neck was significantly more anisotropic than the femoral head. In transverse sections, the craniolateral region of the femoral neck was significantly more anisotropic than the caudomedial and craniomedial regions. CONCLUSIONS AND CLINICAL RELEVANCE: There is a predictable cancellous microarchitecture in the proximal portion of femurs from dogs with moderate osteoarthritis. Trabeculae are more numerous, thicker, and closer together but more randomly arranged in the femoral head than in the femoral neck. Dogs with moderate osteoarthritis had an increase in trabecular anisotropy in the craniolateral region of the femoral neck. However, there was no corresponding increase in trabecular alignment of the proximomedial region of the femoral head. Results support an association between trabecular alignment and the progression of osteoarthritis.     

1例猫股骨头颈部骨折的诊断和治疗

犬猫单纯的股骨头颈部骨折临床上较少,其发病原因是骨盆或股骨受到直接或间接的外力导致,也常继发于髋关节发育不良导致的骨质疏松,轻微的外力就可造成动物的股骨头颈部骨折。介绍了猫股骨头颈部骨折的临床症状、诊断及治疗过程,以供参考。     

Internal fixation of femoral head and neck fractures in the cat

A quick surgical approach for internal reduction and fixation of femoral head and neck fractures is described. The results and reasons for preferring this technique to femoral head and neck excision are discussed.     

Femoral capital physeal fractures in dogs: 34 cases (1979-1989)

Complications associated with femoral capital physeal (CP) fractures in 34 dogs were evaluated. Fractures were surgically repaired, using divergent K-wires or lag screws; radiographic follow-up was available for 21 CP fractures. In all cases, radiographic abnormalities such as degenerative joint disease and resorption of the femoral neck and/or head were seen. Changes were more severe when fracture occurred at an early age. For 4 of 21 dogs (20%), femoral head and neck excision was performed because of complications associated with CP fracture repair. Prognosis for femoral CP fractures is guarded, although affected dogs should be able to function as pets.     

A Retrospective Comparison of Three Techniques for Femoral Head and Neck Excision in Dogs

Femoral head and neck excision was performed in 169 dogs over a 7 year period. A written questionnaire completed by 56 owners, evaluating a total of 72 joints, was the basis for retrospective evaluation of the efficacy of the procedures used. There were four surgical groups: femoral head and neck excision (FHNE) in dogs with body weights over 14 kg, the same procedure in dogs with body weights less than 14 kg (SMALL), femoral head and neck excision with muscle interposition (MI), and the wedge resection technique (WRT). Although differences in results were noted, there were no statistically significant differences between any of the groups for the percentage of leg use during normal activity (p greater than 0.05), mean postoperative time until leg use, use of the leg or hopping while running, or lameness with exercise (p greater than 0.10). The results of this study suggest that there is little advantage in performing the more time-consuming and traumatic muscle interposition and wedge resection procedures.     

Femoral Head and Neck Fractures in the Dog and Cat: A Review of 115 Cases

Case histories of 115 dogs and cats with fractures of the femoral head or neck, were reviewed; these animals had been presented to the Ohio State University Veterinary Hospital between 1969 and 1976. Signalment, fracture type by anatomic location, fracture to fixation interval, surgical approaches used, methods of surgical repair, surgical complications, and final results of surgical repair were examined. Avascular necrosis of the femoral head was not a clinically significant problem following internal fixation in this study. Most animals had very good to excellent limb function following fracture repair.     

PUPPY LINE, METAPHYSEAL SCLEROSIS, AND CAUDOLATERAL CURVILINEAR AND CIRCUMFERENTIAL FEMORAL HEAD OSTEOPHYTES IN EARLY DETECTION OF CANINE HIP DYSPLASIA

Ventrodorsal extended hip radiographs were analyzed from Foxhounds, Irish setters, Greyhounds, and Labrador retrievers radiographed four to seven times between 8 and 110 weeks of age. Occurrence in these 91 dogs of a puppy line, an ill-defined zone of proximal femoral metaphyseal sclerosis, a femoral neck linear sclerosis, or circumferential linear femoral head osteophytosis at 15–17 weeks of age were compared with hip joint laxity, as measured by distraction index, and to later findings of caudal curvilinear femoral neck osteophytes, circumferential femoral head osteophytes, hip incongruity consistent with hip dysplasia and degenerative joint disease by 52 weeks of age. A puppy line and/or femoral metaphyseal sclerosis was common at 15–17 weeks of age for dogs at mimimal risk (Greyhounds) and high risk (Foxhounds) of developing early degenerative joint disease associated with canine hip dysplasia. Though 44% of Greyhound hips had puppy lines and 28% had femoral metaphyseal sclerosis at 15–17 weeks of age, no Greyhound had a caudolateral curvilinear osteophyte or circumferential femoral head osteophyte at 24–27 or 52 weeks of age. No significant relationship was found between occurrence of a puppy line, a circumferential femoral head osteophyte or femoral metaphyseal sclerosis at 15–17 weeks and canine hip dysplasia or degenerative joint disease incidence at 42–52 weeks. Presence of a caudolateral curvilinear osteophyte in at least one hip at 24–27 weeks was significantly related to the diagnosis of canine hip dysplasia by 42–52 weeks. When both a caudolateral curvilinear osteophyte and a circumferential femoral head osteophyte were present in a hip at 24–27 weeks, degenerative joint disease was evident in all such hips by 42–52 weeks of age.     

Coxofemoral arthroscopy and total hip arthroplasty for management of intermediate grade fibrosarcoma in a dog

OBJECTIVE: To report the use of arthroscopy and total hip arthroplasty (THA) for management of intermediate grade fibrosarcoma of the femoral head in a dog. STUDY DESIGN: Clinical case report. ANIMAL: A 6-year-old spayed female Rottweiler presented for evaluation of acute-onset of lameness of the right pelvic limb of approximately 10 days duration. METHODS: Coxofemoral arthroscopy was performed to obtain fine needle aspiration and Jamshidi biopsy of a lytic lesion of the femoral head. A cemented THA was performed removing as much of the femoral neck and proximal femur as possible while not compromising implant or joint stability. RESULTS: Histologic evaluation of specimens from the femoral head and neck remnants confirmed an intermediate grade fibrosarcoma. Fifteen months after THA, subjectively there was normal use of the right limb with only limited decrease in range of motion and mild muscular atrophy. Radiographs demonstrated stationary positioning of the THA implants. CONCLUSIONS: Arthroscopy of the coxofemoral joint is an effective diagnostic tool for evaluation of disease of the articular structures and canine total hip replacement may be an appropriate means of limb salvage in rare cases of disease of the femoral head. CLINICAL RELEVANCE: This case provides support for the use of coxofemoral arthroscopy as a diagnostic tool as well as an aid in acquiring representative intraarticular tissue samples. Additionally, the case presented demonstrates the potential use of THA as a limb sparing technique in cases of disease affecting the femoral head of dogs.     

Comparison of femoral inclination angle measurements in dysplastic and nondysplastic dogs of different breeds

In this study, inclination angle of the femoral head and neck was measured on 484 limbs of 242 dogs belonging to 7 breeds, examined for hip dysplasia. These inclination angles were compared according to age, sex and joint laxity, evaluated with Subluxation Index (SI) and Norberg angle (NA) results. The findings indicate that (a) there was a minimal (nonsignificant) difference in femoral inclination angle between the dysplastic and nondysplastic dogs belonging to 7 breeds; (b) although there was no significant difference in femoral inclination angle between the nondysplastic dogs belonging to 4 breeds (Pointer, Irish Setter, Golden Retriever and German Shepherd), a significant difference was observed between Doberman and Labrador, and between Anatolian Karabash and the other six breeds (p < 0.001). Age and sex did not affect the femoral neck angle.     

The effects of femoral stem and neck length on cement strains in a canine total hip replacement model

OBJECTIVE: To determine the effects of femoral prosthesis stem length and head size on cement strains in a canine hip replacement system. STUDY DESIGN: An in vitro experimental model. SAMPLE POPULATION: (1) Three standard and 3 1-cm shortened femoral implants with +3 femoral heads. (2) Two standard implants with +0, +3, and +6 femoral heads. METHODS: Femoral stems were embedded in polymethylmethacrylate cement. A uniaxial proximodistal-oriented strain gauge was applied to the cement on the medial and lateral aspects of the construct 1.5 cm, 6.0 cm and 7.0 cm distal to the collar. Each construct with a +3 femoral head was mounted in a materials testing system. An axial compressive load (0-200 N) was applied to the femoral head and cement strains were recorded. Additionally, 2 standard length constructs were also tested with +0 and +6 femoral heads. The effects of stem length and neck length on cement strains were assessed with analysis of variance. RESULTS: Strains increased at all locations with increasing loads for all constructs. Shorter implants had higher strains by 152% and 171%, lateral (P =.003) and medial (P =.0025) to the stem tip. No significant strain differences were noted, at any strain gauge location, between different neck lengths (P values ranged from.20 to.67). CONCLUSIONS: Although a shorter implant stem has a potential to improve implant fit, it led to significantly higher cement strains that may increase the risk for aseptic loosening. Changes in femoral neck length did not significantly affect cement strains under the conditions tested. CLINICAL RELEVANCE: Shortening of the femoral stem currently cannot be recommended in canine total hip replacement. The existing use of variable neck lengths likely does not increase the risk of failure of the femoral stem.     

Changes in the Proximal Femur and Coxofemoral Joint Following Intramedullary Pinning of Diaphyseal Fractures in Young Dogs

We report radiographic changes and clinical results seen in the proximal femur and coxofemoral joint of 7 young dogs following intramedullary pinning. Changes seen radiographically included coxa valga, a small malformed femoral head, a short thin femoral neck, and coxofemoral subluxation. Epiphyseal trauma, ischemia, and mechanical impairment of normal femoral neck growth due to presence of the intramedullary pin are discussed as possible etiologic factors.     

Hip dysplasia in koalas (Phascolarctos cinereus) at the San Diego Zoo.

A retrospective/prospective radiographic study documented 55 cases of moderate to severe hip dysplasia, with varying degrees of shallowing of the acetabulum, flattening or loss of the femoral head, widening or loss of the femoral neck, and femoral diaphyseal abnormalities in northern koalas (Phascolarctos cinereus) in the San Diego Zoo (San Diego, California, USA) collection. For the retrospective study, historic radiographs were examined when availble. For the prospective study, three standard views (ventrodorsal extended leg, ventrodorsal frog leg, and lateral extended leg) were used. A scoring system was developed using four areas (acetabulum, femoral head, femoral neck, and femur) and ranges of 0 to 5 (0 = not affected to 5 = severely affected) for each area, creating a total score out of 40. Scores were graded as follows: 0-2 = normal dysplasia; 3-6 = mild dysplasia; 10-19 = moderate dysplasia; and 20-40 = severe dysplasia. Thirty koalas were graded as severe, 25 koalas as moderate, and 38 koalas as excellent or mild. Affected koalas may or may not demonstrate gait abnormalities. Mild to severe degenerative joint disease may develop and symptoms may be alleviated with glucosamine/chondroitin sulfate and nonsteroidal anti-inflammatory drugs. The etiology of hip dysplasia in koalas is not currently understood.     

Use of external coaptation for the treatment of avascular necrosis of the femoral head in a dog

Avascular necrosis of the femoral head was diagnosed in a 5-month-old Schipperke, before the development of femoral head and neck collapse and resultant degenerative joint disease. External coaptation, consisting of an Ehmer sling, was used to prevent the bearing of weight during revascularization and reossification of the subchondral bone. Results of pelvic radiography (at 10 and 24 weeks) indicated that the early use of conservative treatment was successful in promoting resolution of the aseptic necrosis and in maintaining normal coxofemoral anatomic features and function.     

Influence of femoral head and neck conformation on hip dysplasia in the German Shepherd dog.

We investigated the prevalence of an anatomic variant of the proximal femur, termed the broomstick-like femoral head and neck formation, and its influence on the Féderation Cynologique Internationale (FCI) hip dysplasia score in 294 German Shepherd dogs. One-hundred and eighty (61%) of the 294 dogs in our study had this anatomic variant. The calculated area of the femoral heads in dogs with a broomstick-like conformation was 4.5 +/- 0.6 cm2 on the hip-extended view. In dogs with a normal femoral head, the calculated area of the femoral head was significantly larger at 4.8 +/- 0.6 cm2 (P < 0.05). In the frog-leg view, there was no significant difference in femoral head area between dogs with the broomstick-like conformation and normal dogs. There was no difference in the antetorsion angle between dogs with broomstick-like conformation and normal dogs. There was also no difference in the distraction ratio between the two phenotypes. The official FCI hip score was similar in dogs with and without the broomstick-like conformation. The average heritability of the broomstick-like conformation was 0.3 +/- 0.1, suggesting heritable influence. We conclude that the broomstick-like conformation is a common finding in the German shepherd dog and has genetic base. The broomstick-like conformation does not appear to be associated with the presence of canine hip dysplasia and it can therefore be assumed to be a normal anatomic variant.