In vitro biomechanical comparison of three methods for internal fixation of femoral neck fractures in dogs.

The in vitro biomechanical properties of three methods for internal fixation of femoral neck fractures were evaluated. Fifty cadaveric femura from Beagle dogs were used. Ten intact femora served as controls. In 40 femura, an osteotomy of the femoral neck was performed to simulate a transverse fracture. With the remaining 30 femura, three repair methods (two medium Orthofix pins, a 2.7 mm cortical bone screw placed in lag fashion and an anti- rotational Kirschner wire, or three divergent 1.1 mm Kirschner wires) were used to stabilize the osteotomies, and 10 osteotomies were stabilised per repair method. These 30 femura where then subject to monotonic loading to failure. Construct stiffness and load to failure were measured. In the remaining 10 femura, pressure sensitive film was placed at the osteotomy site prior to stabilization with either two Orthofix pins (n = 5) or a screw placed in lag fashion (n = 5) to determine the compressive pressure (MPa), compressive force (KN) and area of compression (cm²). There was no significant difference in the stiffness or load to failure for the three repair methods evaluated. There was no significant difference in the compressive pressure, compressive force or area of compression in osteotomies stabilized with Orthofix pins and 2.7 mm bone screws.

Young, male neutered, obese, lame? Non-traumatic fractures of the femoral head and neck.

PATIENT GROUP: Young, male neutered, obese cats are predisposed to sustaining spontaneous capital physeal fractures, as well as fractures of the femoral neck secondary to metaphyseal osteopathy. PRACTICAL RELEVANCE: Although femoral head and neck excision generally leads to adequate limb function, and is appropriate for chronic fractures, it is a salvage procedure and irreversible. Ideally, for acute capital physeal fractures an attempt should be made to stabilise the fracture and save the coxofemoral joint. This requires early detection of the femoral fracture. CLINICAL CHALLENGES: Orthopaedic examination in cats can be challenging. Yet thorough assessment is needed to allow localisation of the pathology to the hip joint, and to rule out other orthopaedic conditions such as cranial cruciate ligament rupture. Stabilisation of these types of fracture may also prove challenging. AUDIENCE: This review is aimed at general practitioners who have some experience in orthopaedic surgical procedures, as well as those simply wishing to expand their knowledge of feline orthopaedic conditions.

Hybrid cemented/cementless total hip replacement in dogs: seventy-eight consecutive joint replacements.

OBJECTIVE: To evaluate the use of hybrid total hip replacement (THR), using a cementless acetabular component and a cemented femoral component. STUDY DESIGN: Prospective case series. SAMPLE POPULATION: Client-owned dogs (n = 71). MATERIALS AND METHODS: Consecutive clinical cases that had hybrid THR were studied. Radiographic features, pain scores, and lameness scores were recorded pre- and postoperatively. Longer term outcome was assessed by owner questionnaire. RESULTS: Hybrid THRs (n = 78) were performed in 71 dogs. Four cases (5%) had major postoperative complications; 3 were resolved after revision surgery, and 1 owner requested an explantation. No other major complications were identified on follow-up radiographs (67 THR) at 12 weeks. On clinical follow up (77 THR) at 4 weeks, lameness had improved in 68, was unchanged in 8, and was worse in 1. Pain had decreased in 72, was unchanged in 4, and was worse in 1. At 12 weeks (69 THR) compared with preoperative status, lameness had improved in 67 and was unchanged in 2. Pain had improved in 68 and was unchanged in 1. Longer term follow-up (mean, 16 months) was available for all hips. No further complications were reported. Owner satisfaction was good for 76 THRs and reasonable for 2. CONCLUSIONS: Hybrid THR can be performed successfully with a low complication rate and represents an alternative to either entirely cemented or cementless implantation.

Successful management of simple fractures of the femoral neck with femoral head and neck excision arthroplasty in two free-living avian species.

A red-tailed hawk (Buteo jamaicensis) and a Canada goose (Branta canadensis) were evaluated for unilateral pelvic limb lameness. Physical examination findings and results of diagnostic imaging revealed femoral neck fractures in both birds. Both birds were treated with a femoral head and neck excision arthroplasty. The affected legs were not immobilized, and the birds were encouraged to use the legs immediately after surgery to encourage formation of a pseudoarthrosis. Within 2 weeks, both birds were using the affected limb well enough to be either successfully released or transferred to a wildlife rehabilitation facility. Femoral head and neck excision arthroplasty without immobilization of the limb is recommended for managing avian femoral neck fractures, especially in free-ranging species in which a rapid and complete or near complete return to function is vital for survival in the wild.

Comparison of the diagnostic value of ultrasonography and standing radiography for pelvic-femoral disorders in horses.

OBJECTIVE: To assess agreement between ultrasonography (transcutaneous and transrectal) and standing radiography in horses with fractures in the pelvic region and disorders of the coxofemoral joint. STUDY DESIGN: Case series. ANIMALS: Warmblood horses (n=23) and 2 ponies. METHODS: Medical records (1999-2008) of equids with pelvic or coxofemoral disorders that had pelvic radiography and ultrasonography were retrieved and results of both techniques compared. RESULTS: Radiography and ultrasonography each identified equal numbers of fractures of the tuber coxa (n=4), ilial shaft (2), ischium (3), femoral neck (2), and osteoarthritis/osis of the coxofemoral joint (6). Fractures of the ilial wing (4) were only identified by ultrasonography not by standing radiography. Of 9 acetabular fractures, 3 were identified on radiographs only, 5 were identified with both modalities. One pubic fracture was identified using ultrasonography and radiography. One acetabular and 1 pubic fracture were only diagnosed on necropsy. CONCLUSIONS: We found reasonable agreement (73%; 24/33) between ultrasonography and standing radiography for diagnosis of pelvic-femoral disorders. Ultrasonography was more useful for ilial wing fractures and radiography for acetabular fractures. CLINICAL RELEVANCE: Ultrasonography is a rapid, safe imaging technique for detecting disorders of the pelvic region with a high diagnostic yield and is a preferred initial approach in horses with severe hindlimb lameness.

Pathological fractures secondary to metaphyseal osteopathy in a dog.

A four-month-old German Shepherd Dog (GSD) was admitted with bilateral non-weight bearing hindlimb lameness and pyrexia. A diagnosis of bilateral distal femoral fractures secondary to metaphyseal osteopathy was made on the basis of clinical signs, radiography and biopsy. The dog returned to normal function following conservative management. As far as the authors are aware there are no previous reports of pathological fractures secondary to this condition.

Surgical treatment of a vertebral fracture associated with a haematogenous osteomyelitis in a dog.

A seven-month-old Rottweiler was referred for a diagnosed femoral neck fracture and a suspected vertebral fracture. The simplified neurological examination revealed an acute paraplegia. A discospondyilitis associated with a pathologic fracture of Th11 and a spinal compression, and a haematogenous epiphysitis of the femoral neck were diagnosed based on radiographic and computed tomographic examinations. The vertebral fracture was stabilised using screws and polymethylmetacrylate with gentamycin by a lateral intercostal approach. The dog was able to walk seven days later. A femoral head and neck ostectomy was performed two weeks later. Staphylococcus intermedius was isolated from both sites, which confirmed the diagnosis. The dog was treated with cephalexin (30 mg/kg/d) for six weeks. A telephone interview with owners indicated that no more clinical signs were present four months after the second surgery. Discospondylitis associated with haematogenous osteomyelitis has only been reported in two cases. Paraplegia is an unusual clinical presentation for discospondylitis. The lateral approach (which allowed a direct access to the infected site) and the technique (screws associated with antibiotic-impregnated cement) are unique for surgical treatment of discospondylitis. Although applying cement to an infected area may pose a risk, antibiotic-loaded cement is successfully used in the treatment of chronic osteomyelitis in humans.

In vitro biomechanical comparison of limited contat dynamic compression plate and locking compression plate.

The locking compression plate (LCP) supports biological osteosynthesis by functioning as an internal fixator, rather than as a full or limited contact bone plate which must be adequately contoured and affixed directly to the bone for stable internal fixation of the fracture. In order to help justify the use of the LCP in our veterinary patients, in vitro biomechanical testing was performed comparing the LCP to the conventional limited contact dynamic compression plate (LC-DCP) in canine femurs. We hypothesized that the LCP construct would be at least as stiff under bending and torsional loads as the LC-DCP. The LCP and LC-DCP were applied over a 20-mm osteotomy gap to contralateroal bones within each pair of 14 femora. Non-destructive four-point bending and torsion, and cyclical testing in torsion were performed. The constructs were then loaded to failure in torsion. In medial-lateral and lateral-medial structural bending, significant differences were not found between the LCP and LC-DCP, however, at the gap, the LCP construct was stiffer than the LC-DCP in lateral-medial bending. Significant differences in behaviour over time were not noted between the plate designs during cyclical testing. When loading the constructs to failure in internal rotation, the LC-DCP failed at a significantly lower twist angle (P = .0024) than the LCP. Based on the similar performance with loading, the locking compression plate is a good alternative implant for unstable diaphyseal femoral fracture repair in dogs.

Surgical reduction and stabilization for repair of femoral capital physeal fractures in cats: 13 cases (1998-2002).

OBJECTIVE: To evaluate anatomic reduction and surgical stabilization of femoral capital physeal fractures in cats. DESIGN: Retrospective study. ANIMALS: 13 cats. PROCEDURE: Medical records of cats with unilateral or bilateral femoral capital physeal fractures evaluated from 1998 to 2002 were reviewed. Age and weight of cats at the time of surgery; breed; sex; concurrent injuries; severity of lameness before and 1, 2, 4, 6, and 8 weeks after surgery; the amount of fracture reduction achieved and number of Kirschner wires (K-wires) used; degree of degenerative joint disease of the hip joint and lysis of the femoral neck and head observed after surgery; whether K-wires were removed after surgery; and complications after surgery were evaluated. RESULTS: Thirteen cats with 16 capital physeal fractures were identified. There was significant improvement in the severity of clinical lameness in all cats from weeks 1 through 4 after surgery. There was no correlation between the scores of the individuals who evaluated radiographs for fracture reduction and placement of K-wires. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that surgical stabilization and repair of femoral capital physeal fractures facilitate a short recovery period and a good prognosis for return to normal function in cats.

Repair of femoral capital physeal fractures in 12 cattle.

OBJECTIVE: To document signalment, clinical signs, and long-term outcome of surgical treatment for femoral capital physeal fractures in cattle. STUDY DESIGN: Retrospective study. Animals-Twelve cattle with femoral capital physeal fractures. METHODS: Cases were identified by a search of radiographic records. Historical, diagnostic, surgical, and outcome data were collected from the medical records. Owners were contacted for follow-up information by telephone. RESULTS: Fractures were repaired by screws inserted in lag fashion in 4 animals and by use of multiple intramedullary pins in 8 animals. Six of 12 animals required repeat surgery to reposition screws or pins. Nine animals were considered successfully treated at discharge. Six months after surgery, 6 of 11 animals for which follow-up was obtained were still sound. At 12 months, 4 of 4 animals alive were still sound. Animals that bore weight earliest postoperatively were more likely to have a successful outcome. Animals <12 months of age had better outcomes than animals >12 months of age. CONCLUSIONS: Prognosis for serviceable soundness is good in cattle <12 months of age and fair in animals >12 months of age after surgical repair of femoral capital physeal fracture by stacking intramedullary pins or by screws inserted in lag fashion. CLINICAL RELEVANCE: Surgical repair of femoral capital physeal fracture is most successful in younger cattle and can result in productive animals.

Femoral neck metaphyseal osteopathy in the cat.

This paper describes 17 cats that developed an idiopathic necrosis of the femoral neck. In four cats the lesions were bilateral when they were first examined and five cats developed lesions in the other limb within five months. They were all male cats, two years old or younger, and 15 had been neutered. The initial sign was a vague lameness which typically progressed, often acutely, to a more severe lameness. Radiography demonstrated radiolucency and loss of definition within the proximal femoral metaphysis, the femoral neck. In 12 cases there was a complete radiolucent line across the femoral neck. An excision arthroplasty was carried out on all the affected hips and the lameness resolved in all cases. The clinical and radiological signs suggest a primary bone resorption with secondary fracture of the femoral neck. The lesions have some similarities with Legg-Calve-Perthes' disease, traumatic fracture of the femoral neck, canine metaphyseal osteopathy, bacterial osteomyelitis and experimental feline herpes virus osteomyelitis.

Determination of safe depth of pin penetration for repair of distal femoral physeal fractures in immature dogs: a comparison of normograde and retrograde pin placement.

OBJECTIVE: The purpose of this study was to determine the depth that implants may be safely placed into the distal femoral epiphysis (DFE) for the repair of distal femoral physeal fractures. STUDY DESIGN: The depth of the DFE was related to the radiographic thickness of the patella in this experimental study. ANIMALS OR SAMPLE POPULATION: Twenty immature canine cadavers. METHODS: Patella thicknesses were measured from lateral radiographs. Actual DFE depths were determined for pins driven in normograde fashion and for pins driven retrograde from the central depression between the metaphyseal pegs and from the cranial pegs. The association of DFE depth and patella thickness was evaluated using linear regression analysis. Using 95% confidence intervals, rules for estimating the safe depth of implant placement into the DFE were determined. RESULTS: DFE depth had significant correlation with patella thickness for pins placed in retrograde fashion from the central depression between the metaphyseal pegs (r2 = .83) and from the cranial pegs (r2 = .82) and for pins placed in normograde fashion (r2 = .65). CONCLUSIONS: Based on 95% confidence intervals, pins placed in retrograde fashion from the central depression between the metaphyseal pegs may be safely driven into the DFE a distance equal to 140% of patella thickness. Pins placed from the cranial metaphyseal pegs may be driven to a depth equal to 80% of patella thickness, and pins placed in normograde fashion may be driven to a depth equal to 30% of patella thickness. CLINICAL RELEVANCE: Measurement of patella thickness assists the surgeon in determining the approximate depth that pins may be driven into the DFE without penetrating the articular surface of the stifle joint.

Femoral capital physeal fractures in 25 foals.

The medical records of 25 horses 1 year of age or younger affected with femoral head and neck fractures during an 18 year period were reviewed. Each fracture involved the capital physis. The foals were 11 days to 12 months of age (mean, 5 months). No femoral capital physeal fractures occurred in horses older than 1 year of age during the same period. The history in each case included acute onset of severe unilateral hindlimb lameness, 3 hours to 2 months (mean, 12 days) before presentation. Injuries observed were violent falls, struggles, and kicks. Crepitation, swelling, pain with manipulation or palpation or both, and apparent fracture fragment displacement were inconsistently noted. Tentative clinical diagnoses were confirmed by radiography in 24 foals and by necropsy alone in one foal. Twenty-one foals were euthanatized due to poor prognosis. One foal sent home for stall rest was lost to follow-up. Surgical repair was attempted in three foals. Two fractures were repaired with multiple intramedullary pins and the foals were euthanatized within 2 weeks due to surgical failure and, in one case, contralateral limb breakdown. The third fracture was repaired with a compressing screw and plate device; the animal was pasture sound at month 20.

[Proximal femoral fractures in cats and dogs]. / Proximale Femurfrakturen bei Katze und Hund.

Fractures of the femoral head, neck and greater trochanter including physeal separations are common in the growing dog and cat. These lesions are discussed and illustrated from the standpoints of the anatomy and pathophysiology, etiology, diagnosis and surgical therapy. The prognosis is favorable under the conditions of early anatomical reduction, gentle tissue handling to preserve the blood supply and stable internal fixation. Persistent avascular necrosis of the femoral head as seen in human patients does not appear as a complication in small animals. This review is based on 235 internal fixations out of which 145 are reevaluated clinically as well as radiographically.