Biomechanical effects of a titanium intervertebral cage as a stand-alone device, and in combination with locking plates in the canine caudal cervical spine.

OBJECTIVE: To evaluate the change in ex vivo biomechanical properties of the canine cervical spine, due to an intervertebral cage, both as a stand-alone device and in combination with plates. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Cervical spinal segments (C5-C7) from eight canine cadavers. METHODS: The range of motion (ROM) and elastic zone stiffness (EZS) of the spines were determined with a four-point bending device in flexion/extension, lateral bending, and axial rotation for four conditions: native, discectomy, cage (at C6-C7), and cage with plates (at C6-C7). The disc height index (DHI) for each condition was determined using radiography. RESULTS: Discectomy resulted in overall increased ROM (p < .01) and EZS (p < .05) and decreased DHI (p < .005) when compared to the native condition. Placement of the cage increased DHI (p < .001) and restored total ROM during flexion/extension, lateral bending and axial rotation, and EZS during flexion/extension to the level of the native spine. Application of the plates further reduced the total ROM during flexion/extension (p < .001) and lateral bending (p < .001), but restored ROM in extension and EZS during lateral bending. No implant failure, subsidence, or significant cage migration occurred during loading. CONCLUSION: An anchorless intervertebral cage used as a stand-alone device was able to restore the disc height and spinal stability to the level of the native cervical spine, whereas the addition of plates further reduced the spinal unit mobility. CLINICAL SIGNIFICANCE: This study implies that the intervertebral cage may be used as a stand-alone device in the spinal unit fixation in the canine cervical spine.

Ex vivo study of minimally invasive procedures for cartilage removal from the metacarpophalangeal or metatarsophalangeal joint and for fetlock tension band application.

OBJECTIVE: To describe reliable minimally invasive procedures for (1) removing cartilage by joint distraction and articular drilling for equine metacarpophalangeal (MCP)/metatarsophalangeal (MTP) arthrodesis; (2) applying a palmar/plantar tension band without MCP/MTP joint luxation. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric equine limbs (n = 12). METHODS: All limbs were used to evaluate the drilling technique. First the MCP/MTP joint was distracted with a 5.5-mm cortical screw. Then, through four stab incisions, articular cartilage was removed with a 4.5-mm drill. Six randomly chosen limbs were then tested for minimally invasive tension band application with a specially designed cannula. Accurate positioning of the tension band was assessed radiographically. All MCP/MTP joints were disarticulated, and the areas of removed cartilage were visually assessed and measured by using planimetry. RESULTS: The mean percentage of removed cartilage was 66.8% ± 7.6% for the metacarpus/metatarsus surface, 67.9% ± 8.6% for the proximal phalanx surface, and 59.5% ± 1% for the two sesamoid bones. The tension band could be accurately placed through four stab incisions with the cannula. CONCLUSION: This minimally invasive technique for cartilage removal was efficient and should be favorable for joint fusion in some clinical situations. The minimally invasive tension band application through stab incisions was feasible and repeatable. CLINICAL SIGNIFICANCE: These procedures should allow total minimally invasive MCP/MTP arthrodesis and be used in selected clinical cases.

Comparação biomecânica de CRIF e placa de reconstrução na estabilização de fraturas distais de fêmur em cães / Biomechanical comparison of CRIF and reconstruction plate for stabilization of distal femur fractures in dogs

O presente estudo objetivou comparar, biomecanicamente, por meio do ensaio de compressão excêntrica, a resistência dos implantes Clamp and Rod Internal Fixation (CRIF) 5,0mm e placa de reconstrução 3,5mm na fixação de fraturas distais de fêmur de cão. Foram utilizados 22 fêmures de 11 cadáveres de cão entre 2 e 7 anos de idade e peso corporal entre 20 e 40kg e subdivididos em dois grupos, denominados grupo CRIF (GC - 11 fêmures) e grupo placa (GP - 11 fêmures). Para realização dos testes, foi simulada falha que mimetizasse uma fratura distal nos corpos de prova, por meio de uma osteotomia de até 0,5cm, realizada com auxílio de serra oscilatória, imediatamente proximal ao início da tróclea. Os implantes foram fixados segundo os padrões AOSIF, lateralmente ao fêmur, sendo utilizados três parafusos distais e cinco proximais ao foco de fratura. Foi empregado o programa de computador PMI para calcular o ponto máximo de resistência antes da falha e avaliaram-se as variáveis força máxima, deformação máxima real, rigidez, força intermediária e deformação intermediária real. Não foram encontradas diferenças estatisticamente significativas entre os GC e GP quanto às variáveis avaliadas, sugerindo que ambos os implantes são boas opções de fixações para tais fraturas.(AU)

This study aims to compare the biomechanical properties, through compression eccentric test, of the resistance of the 5.0mm Clamp and Rod Internal Fixation Implants (CRIF) and 3.5mm reconstruction plate in fixing dog femur distal fracture. It was used 22 femurs from 11 dog cadavers with age between 2 and 7 years old and body weight between 20 and 40kg, subdivided into two groups, called CRIF Group (CG - 11 femurs) and plate group (PG - 11 femurs). A distal fracture in the specimens with a gap of 0.5cm osteotomy, was simulated to perform the test, performed by the oscillating saw, just proximal to the beginning of the trochlea. The implants were fixed by the standards AO / SIF, laterally to the femur, using three distal screws and five proximal to the fracture site. PMI computer program was used to calculate the maximum point of resistance before failure and evaluated the variables maximum strength, real maximum deformation, stiffness, intermediate strength and real intermediate deformation. No statistically significant differences were found between the GC and GP as the variables evaluated, suggesting that both implants are good fixation options for such fractures.(AU)

Canine Vertebral Screw and Rod Fixation System: Design and Mechanical Testing.

OBJECTIVES: To develop the canine vertebral screw and rod fixation system (CVSRF) and to compare the biomechanical properties between CVSRF and the screw and polymethylmethacrylate (Screw-PMMA) technique for internal fixation of the vertebral column in dogs. METHODS: The CVSRF consisted of vertebral screws with monoaxial side-loaded head, rods and specific inner screws connecting rod to the screw head. The CVSRF prototype was made from titanium alloy and manufactured by the rapid prototype machine. Vertebrectomy models were simulated by ultra-high-molecular-weight polyethylene blocks and tested with the CVSRF system (n = 8) and the Screw-PMMA technique (n = 8). The models were developed according to the American Society for Testing and Materials (ASTM F-1717-04). The biomechanical parameters were the compressive bending yield load, the compressive bending stiffness, the compressive ultimate load and the load displacement curve. RESULTS: The mean values of the compressive bending yield load, compressive bending stiffness and compressive ultimate load of the CVSRF were significantly higher than those of the Screw-PMMA technique (p < 0.01). The load displacement curve of the CVSRF showed higher rigidity and durability than that of the Screw-PMMA technique. CLINICAL SIGNIFICANCE: This mechanical study indicated that the CVSRF system can be used for canine vertebral stabilization and the biomechanical properties were better than those for the Screw-PMMA device.

Kinematic behavior of a novel pedicle screw-rod fixation system for the canine lumbosacral joint.

OBJECTIVE: To determine the biomechanical behavior of a novel distraction-stabilization system, consisting of an intervertebral distraction bolt, polyaxial screws, and connecting rods, in the canine lumbosacral spine. STUDY DESIGN: Biomechanical study. SAMPLE POPULATION: Cadaveric canine lumbosacral spines (L4-Cd3) (N = 8). METHODS: Cadaveric lumbosacral spines were harvested, stripped of musculature, mounted on a 4-point bending jig, and tested in extension, flexion, and lateral bending using nondestructive compressive axial loads (0-150 N). Angular displacement was recorded from reflective optical trackers rigidly secured to L6, L7, and S1. Data for primary and coupled motion were collected from intact spines, after destabilization at L7-S1, and following surgical stabilization with the new implant system. RESULTS: As compared with the intact spine, laminectomy resulted in a modest increase in angular displacement at L6-L7 and a marked increase at L7-S1. Instrumentation significantly reduced motion at the operated level (L7-S1) with a concomitant increase at the adjacent level (L6-L7). CONCLUSION: The combination of a polyaxial pedicle screw-rod system and intervertebral spacer provides a versatile solution of surgical stabilization of the lumbosacral joint following surgical decompression in the canine lumbosacral spine. The increase in motion at L6-L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question. CLINICAL RELEVANCE: These results support the feasibility of using this new implant system for the management of degenerative lumbosacral disease in dogs. The increase in motion at L6-L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question.

Accuracy and safety of pin placement during lateral versus dorsal stabilization of lumbar spinal fracture-luxation in dogs.

OBJECTIVE: To determine the accuracy and safety of pin placement for lateral vertebral stabilization to the reference dorsal stabilization. STUDY DESIGN: A randomized noninferiority trial. SAMPLE POPULATION: Twenty Greyhound cadaveric lumbar spines (L1-L6). METHODS: One hundred and fifty-nine lumbar vertebral pins placed in 80 vertebrae were assessed; these pins were distributed approximately equally between the dorsal and lateral approaches, and between 2 surgeons. Pin angle accuracy, bone purchase distance, and distances from pin to the spinal canal and the aorta were measured for each pin. RESULTS: The lateral approach was superior for pin angle accuracy and bone purchase. The mean angle of deviation was 15.3° with the dorsal approach and 7.0° with the lateral approach. The mean bone purchase was 16.7 mm with the dorsal approach and 22.2 mm with the lateral approach. Pins were placed at a mean of 2.3 mm from the spinal canal with the dorsal approach and 1.7 mm with the lateral approach. Pins were placed at a mean of 3.8 mm from the aorta with the dorsal approach and 8.0 mm with the lateral approach. The percentage of pins breaching the spinal canal was 14% with the dorsal approach and 19% with the lateral approach. Fourteen percent of pins placed via the dorsal approach breached the aorta, whereas no pins placed via the lateral approach breached the aorta. CONCLUSION: Relative to the dorsal approach, the lateral approach improves angle accuracy, bone purchase, and distance between pins, and the aorta and is noninferior with regards to the distance between pins and the spinal canal.

Mechanical analysis of transversal iliac fracture stabilization using dynamic compression plate or screws and PMM in polyurethane bone model / Avaliação mecânica de estabilização de fratura ilíaca transversa com placa de compressão dinâmica ou polimetilmecatrilato associado à parafusos utilizando modelo de osso sintético de poliuretano

Pelvic fractures correspond to 20 to 30 % of the fractures observed in dogs. Complete fractures, especially with bone axis deviation should be surgically treated. The mechanical study of surgical techniques is of utmost importance to assess the best way of treating these injuries. This study compared, biomechanically, the use of a dynamic compression plate (DCP) and screws (group 1) or screws and polymethylmethacrylate (PMMA) (group 2) to stabilize an iliac fracture using a static test. Sixteen canine synthetic hemi-pelvises (test specimens) with a transverse iliac osteotomy were used. After fixation with implants, a load was applied to the acetabulum until failure. Group 1 maximal compressive load was 133.9±18.60 N, displacement at yield 21.10±3.59mm and stiffness 125.22±12.25N/mm. Group 2 maximal compressive load was 183.50±27.38N, displacement at yield 16.66±5.42mm and stiffness 215.68±33.34N/mm. The stabilization with polymethylmethacrylate was stronger than dynamic compression plate since it resisted a greater load in all test specimens.(AU)

As fraturas da pelve são frequentes em cães, correspondendo a 20-30% das fraturas encontradas na espécie. A grande maioria delas é tratada cirurgicamente, principalmente aquelas que apresentam desvio ósseo. O estudo mecânico das técnicas cirúrgicas é de extrema importância para avaliação da melhor maneira de tratamento destas lesões. O objetivo deste estudo foi comparar, do ponto de vista biomecânico, a fixação das fraturas do ílio utilizando uma placa de compressão dinâmica ou parafusos associados ao polimetilmetacrilato, por meio de um teste estático. Foram utilizadas 16 hemipelves caninas de origem sintética, nas quais uma osteotomia transversa foi realizada no corpo do ílio. As fixações foram divididas em dois grupos: fixação com placa de compressão dinâmica e parafusos (grupo1) ou parafusos associados ao polimetilmetacrilato (grupo 2). Posteriormente à fixação dos implantes foi aplicada uma carga no acetábulo de cada corpo de prova até a falha. O grupo 2 apresentou força máxima de aplicação de carga a média de 133.9±18.60N, deflexão 21.10±3.59mm e rigidez 125.22±12.25N/mm. O grupo 2 apresentou força máxima de aplicação de carga a média de 183.50±27.38N, deflexão 16.66±5.42mm e rigidez 215.68±33.34N/mm. A estabilização com o polimetilmetacrilato mostrou ser mais resistente, pois resistiu a uma maior quantidade de carga em relação à placa de compressão dinâmica, em todos os corpos de prova.(AU)

Magnetic resonance imaging of an equine fracture model containing stainless steel metal implants.

REASONS FOR PERFORMING STUDY: Post operative imaging in subjects with orthopaedic implants is challenging across all modalities. Magnetic resonance imaging (MRI) is preferred to assess human post operative musculoskeletal complications, as soft tissue and bones are evaluated without using ionising radiation. However, with conventional MRI pulse sequences, metal creates susceptibility artefact that distorts anatomy. Assessment of the post operative equine patient is arguably more challenging due to the volume of metal present, and MRI is often not performed in horses with implants. Novel pulse sequences such as multiacquisition variable resonance image combination (MAVRIC) now provide improved visibility in the vicinity of surgical-grade implants and offer an option for imaging horses with metal implants. OBJECTIVES: To compare conspicuity of regional anatomy in an equine fracture-repair model using MAVRIC, narrow receiver bandwidth (NBW) fast spin echo (FSE), and wide receiver bandwidth (WBW) FSE sequences. STUDY DESIGN: Nonrandomised in vitro experiment. METHODS: MAVRIC, NBW FSE and WBW FSE were performed on 9 cadaveric distal limbs with fractures and stainless steel implants in the third metacarpal bone and proximal phalanx. Objective measures of artefact reduction were performed by calculating the total artefact area in each transverse image as a percentage of the total anatomic area. The number of transverse images in which fracture lines were visible was tabulated for each sequence. Regional soft tissue conspicuity was assessed subjectively. RESULTS: Overall anatomic delineation was improved using MAVRIC compared with NBW FSE; delineation of structures closest to the metal implants was improved using MAVRIC compared with WBW FSE and NBW FSE. Total artefact area was the highest for NBW FSE and lowest for MAVRIC; the total number of transverse slices with a visible fracture line was highest in MAVRIC and lowest in NBW FSE. CONCLUSION: MAVRIC and WBW FSE are feasible additions to minimise artefact around implants.

Influence of a titanium mesh on the management of segmental long bone defects. An experimental study in a canine ulnar model.

OBJECTIVES: To evaluate the influence of titanium mesh on guided bone regeneration when used, either alone or in combination with autogenous bone block graft, in a canine ulnar model. METHODS: Thirty-two, purpose bred, adult, castrated male Beagles were used, divided into four equal-size groups. A unilateral mid-diaphyseal ulnar critical-size defect was created in each dog. The ulnar segments were stabilized with a stainless-steel plate and screws. Each defect was managed by: no further treatment (Group A) or by placement of a bone block graft taken from the ipsilateral iliac crest (Group B), or titanium mesh wrapped around the ulna (Group C), or a bone block graft and titanium mesh (Group D). After six months, bone block biopsies were performed and the samples were scanned using micro-computed tomography. Qualitative histological evaluation was performed on two non-decalcified longitudinal sections from each block. RESULTS: No significant differences in terms of mineralized bone volume were detected between the grafted sites (Groups B and D) or between the non-grafted ones (Groups A and C). The histological evaluation indicated good integration of the bone blocks irrespective of the use of titanium mesh. CLINICAL SIGNIFICANCE: The use of titanium mesh does not influence the amount of bone formation. The canine ulnar critical-size defect model seems to be a reliable model to use in experimental studies.

Bending strength and stiffness of canine cadaver spines after fixation of a lumbar spinal fracture-luxation using a novel unilateral stabilization technique compared to traditional dorsal stabilization.

OBJECTIVE: To 1) assess the bending strength and stiffness of canine cadaver spines after fixation of a lumbar spinal fracture-luxation using a novel unilateral stabilization technique with pins and polymethyl methacrylate (PMMA) and 2) compare the results to a reference standard dorsal pin and PMMA technique. STUDY DESIGN: A randomized non-inferiority trial. SAMPLE POPULATION: Cadaveric lumbar spines (L1-L6) from 20 Greyhounds. METHODS: Specimens were paired to match bodyweight and vertebral size. A standardized fracture/luxation was performed between L3 and L4. One spine within each pair was randomly assigned the unilateral fixation technique and the other received the reference standard dorsal fixation technique. Four-point bending of each specimen in flexion was performed by applying load to pins placed transversely into vertebrae L1, L2, L5, and L6. During testing, angular bending strength and stiffness were measured as a function of flexion angle. Margins for non-inferiority were defined a priori. Strength and stiffness of the specimens for each technique were compared statistically. RESULTS: Lower limits of 95% confidence intervals were above the defined margins for non-inferiority. Thus, based on these margins, for strength and stiffness, unilateral fixation was not inferior to dorsal fixation. CONCLUSIONS: This novel unilateral approach to lumbar spinal fixation yielded comparable strength and stiffness when tested for bending in flexion to that of reference standard dorsal approach. This approach is therefore a suitable alternative to the dorsal approach in appropriate lumbar spinal fracture configurations.

Treatment of a unicameral bone cyst in a dog using a customized titanium device.

A 4-year-old Shih-Tzu, referred for an enlarged left carpus, was diagnosed with a unicameral bone cyst. A customized titanium device was inserted into cystic lesion and fixed by titanium screws. Sufficient strength of the affected bone with the device inserted to maintain limb function was established after resection of contents of cystic lesion. There was no deterioration of the lesion of bone cyst, and acceptable function of the affected limb with no clinical signs of lameness was maintained during 36 months follow-up. The results of this study demonstrated that bone cyst curettage and use of a customized titanium device could provide an effective alternative treatment of huge lesion of unicameral bone cysts with the intent of preventing pathologic fractures.

Bone healing by using Ilizarov external fixation combined with flexible intramedullary nailing versus Ilizarov external fixation alone in the repair of tibial shaft fractures: experimental study.

PURPOSE: Our research was aimed at studying the radiographic and histological outcomes of using flexible intramedullary nailing (FIN) combined with Ilizarov external fixation (IEF) versus Ilizarov external fixation alone on a canine model of an open tibial shaft fracture. MATERIALS AND METHODS: Transverse diaphyseal tibial fractures were modelled in twenty dogs. Fractures in the dogs of group 1 (n = 10) were stabilized with the Ilizarov apparatus while it was combined with FIN in group 2 (n = 10). RESULTS: On day 14, a bone tissue envelope started developing round the FIN wires. Histologically, we revealed only endosteal bone union in group 1 while in group 2 the radiographs revealed complete bone union on day 28. At the same time-point, the areas of cancellous and mature lamellar bone tissues were observed in the intermediary area in group 2. The periosteal layers were formed of the trabeculae net of lamellar structure and united the bone fragments. The frame was removed at 30 days after the fracture in group 2 and after 45 days in group 1 according to bone regeneration. CONCLUSION: The combination of the Ilizarov apparatus and FIN accelerates bone repair and augments stabilization of tibial shaft fractures as compared with the use of the Ilizarov fixation alone.

Decision analysis for fracture management in cattle.

Bovine fractures are common and each bovine patient is unique, presents innumerable challenges, and requires careful judgment. In cattle the fracture repair usually should be of acceptable quality to not cause a decrease in milk or meat production or interfere with natural breeding. The decision to treat a fracture in cattle is made by evaluating the cost and success rates of the treatment, the value of the animal, and the location and type of fracture.

Rapid prototyping to design a customized locking plate for pancarpal arthrodesis in a giant breed dog.

This report describes the treatment of traumatic carpal hyperextension in a giant breed dog by pancarpal arthrodesis using a custom-made Fixin locking plate, created with the aid of a three-dimensional plastic model of the bones of the antebrachium produced by rapid prototyping technology. A three-year-old 104 kg male Mastiff dog was admitted for treatment of carpal hyperextension injury. After diagnosis of carpal instability, surgery was recommended. Computed tomography images were used to create a life-size three-dimensional plastic model of the forelimb. The model was used as the basis for constructing a customized 12-hole Fixin locking plate. The plate was used to attain successful pancarpal arthrodesis in the animal. Radiographic examination after 74 and 140 days revealed signs of osseous union of the arthrodesis. Further clinical and radiographic follow-up examination three years later did not reveal any changes in implant position or complications.

Surgical treatment of distal tarsal joint luxations in three horses.

The clinical signs, radiographic findings, surgical treatment, and outcome of three horses with luxation of the distal tarsal joints are reported. Two patients showed luxations of the tarsometatarsal joint whereas luxation of the proximal intertarsal joint was found in one case. Open reduction, followed by internal fixation was performed in two horses and closed reduction with a transfixation pin cast was performed in the third. The treatment in all three cases resulted in a satisfactory clinical outcome.

Bilateral calcaneal epiphysiolysis in a dog.

A case of bilateral calcaneal epiphysiolysis in a six-month-old female Dobermann Pinscher is described in this report. The absence of a traumatic event and the clinical, radiographic and histopathological abnormalities led us to the diagnosis of simultaneous bilateral epiphysiolysis of the calcaneus. A tension band and a type II transarticular external fixator were placed. The clinical signs were resolved only temporarily because of the gravity of the bone changes.

A novel combined method of osteosynthesis in treatment of tibial fractures: a comparative study on sheep with application of rod-through-plate fixator and bone plating.

The study compares the efficiency of a new bone fixator combining periostal and intramedullary osteosynthesis to bone plating in treatment of tibial fractures in sheep. Experimental osteotomies were performed in the middle third of the left tibia. Animals were divided into two groups: in one group (four animals) combined osteosynthesis (rod-through-plate fixator, RTP fixator) was applied, and in the other group (three animals) bone plating was used. The experiments lasted for 10 weeks during which fracture union was followed by radiography, and the healing process was studied by blood serum markers reflecting bone turnover and by histological and immunohistochemical investigations. In the RTP fixator group, animals started to load body weight on the operated limbs the next day after the surgery, while in the bone plating group, this happened only on the seventh day. In the RTP fixator group, consolidation of fractures was also faster, as demonstrated by radiographical, histological, and immunohistochemical investigations and in part by blood serum markers for bone formation. It can be concluded that application of RTP fixation is more efficient than plate fixation in the treatment of experimental osteotomies of long bones in sheep.

Treatment of pes varus using locking plate fixation in seven Dachshund dogs.

OBJECTIVES: To describe the surgical treatment of pes varus in Dachshund dogs by medial opening wedge osteotomy of the distal tibia stabilized with a locking plate system and to retrospectively report the clinical and radiographic outcomes. MATERIALS AND METHODS: Lameness in nine limbs of seven Dachshund dogs with pes varus deformity was treated with corrective osteotomy at or near the centre of rotation of angulation as defined by the intersection of the proximal and distal mechanical axes determined on caudo-cranial radiographs. Outcomes evaluated included comparison of pre- and postoperative radiographic measurements of frontal angulation and lameness assessment. RESULTS: Lameness resolved in eight limbs and improved in one limb. All osteotomies healed and no implant complications were detected. Mean preoperative radiographic measurements were: mechanical medial proximal tibial angle (mMPTA) = 91.1° (range 87.6°-95°), mechanical medial distal tibial angle (mMDTA) = 62.1° (range 51.9°-69.6°). Mean postoperative measurements were: mMPTA 92.4° (range 78°-97.5°), mMDTA 81.8° (range 76°-87°). Measurable under- correction was common, though seldom visually or functionally evident. CLINICAL SIGNIFICANCE: Pes varus deformity in Dachshunds can be treated by medial opening wedge osteotomy of the distal tibia stabilized with a locking plate system. Care to preserve the lateral cortex of the osteotomy may help avoid under-correction.

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.