Ch 46 ALD Flashcards

Question

angulation correction axis

Answer 1

hinge point on which rotation of two segments of bone can be made; it is under the control of the surgeon. is an axis and thus is represented by a line around which the angular correction will be completed. axis always possesses a perpendicular relationship to the plane of the deformity

Answer 2

**Opening wedge** osteotomy - opening CORA (on the convex surface of the bone) is used as hinge point - when the bone segments are reangulated, the osteotomy opens - advantages include their versatility and ease of completion - some bone lengthening will occur - less stable configuration - consider locking plate, bridging required

Answer 3

**Closing wedge osteotomy** - basing the ACA on a closing CORA on the concave surface - requiring the removal of a wedge-shaped piece of bone - Bone shortening occurs - bone plates and screws because load sharing can be achieved.

Answer 4

**Radial (cylindrical) osteotomies** - only rules 2 and 3 truly apply to their execution. - involve basing the ACA-CORA at the center of the proposed cylindrical cut, and the actual osteotomy will be offset from the angulation correction axis-CORA by the radius of the arced saw blade - bone will be realigned via the second rule of osteotomies - versatility without the need for additional cuts to be made - maintenance of bone length, - apposition - excellent resistance to shearing loads. - disadvantage: completed only in a single plane.

Answer 5

**Dome osteotomies** - cut a true spherical dome - correct deformities in three planes. Thus, torsion angulation deformities can potentially be corrected with the completion of a single cut. - Limitations as blade must be size-matched with the bone in the widest dimension, which results in size mismatching in the sagittal plane

Answer 6

Bone Plates and Screws - reserved for skeletally mature animals in order to provide an acute, definitive correction - Good to excellent results with minimal complications have been reported - sufficient bone must be present proximal and distal for adequate number of screws. - closing wedge ostectomy is performed to maximize reduction of the bone segments - return to function faster. - Plate fixation requires less intensive postoperative care - locking screw and plate technology makes exact contouring less critical. - multiapical deformities may possess severe degrees of soft tissue contracture that cannot be stretched acutely and thus may be more amenable to gradual correction - gain more area for screw placement, Paley's second rule of osteotomies may be employed,

Answer 7

- placed farther from the neutral axis of the bone, and thus are at a mechanical disadvantage compared with internal fixation - opening wedge osteotomies can minimize surgical invasiveness, allow correctional versatility, and provide the opportunity for bone lengthening. - circular external skeletal fixators concluded that long-term function and cosmesis were good to excellent despite frequent complications. - small fixation wires, circular external skeletal fixators can be used when only small segments of bone are available proximal or distal to the osteotomy, as seen with juxta-articular deformities - angulation correction axis can be established with the hinge axis of the designed frame. - allow gradual correction with the use of an angular motor, positioned on the side opposite the hinge axis, along the CORA plane - soft tissues are able to stretch, and the regenerative response of the bone occurs via properties of distraction osteogenesis - study: frame construction was completed preoperatively utilizing polymer replicas from CT reconstructions - an be designed to accomplish axial elongation - Substantial wound and apparatus care is required postoperatively

Answer 8

cute medial opening wedge osteotomy, IMEX mini HESF All osteotomies healed and fixators were removed between 6 and 12 weeks. Lameness resolved in 18 dachshunds (90%) Lateral patella luxation (LPL) 39.2% , all of which resolved following correction.

Answer 9

11 dogs Guides were abandoned in 2 deformities due to soft tissue tension over 90% of parameters were within the acceptable range of ≤ 5° angulation and rotation or ≤ 5 mm of translation from the VSP. Lameness scores were improved in 7/8 deformities Complications included reduced range of carpal motion (n = 2), implant sensitivity (n = 2), fracture (n = 1), and tendon laceration (n = 1). facilitated accurate antebrachial limb deformity correction in the majority of deformities in this case series. A systematic review found that AM implants resulted in reduced surgery time, increased accuracy, and improved outcomes in humans

Answer 10

Hemiepiphysiodesis for Femoral Valgus in 11 Growing Dogs The mean correction 11 degrees, which was significant. Undercorrection > 2/17 cases 11% implants removed 12/17 > round growth in 3/12 (25%) Monitoring with serial radiography is important. Implant removal when the desired aLDFA has been achieved Age = influences the success of the procedure. Residual growth can result in undercorrection, overcorrection or rebound growth. The average age 5.3 months. femoral physis closure 8 - 11mths Under corrections may be due to: - dogs older > 6months may not benefit (residual growth not sufficient) - suboptimal implant positioning across the growth plate Compared to Distal femoral corrective osteotomy, hemiepiphysiodesis less invasive nature, low morbidity, less-demanding postoperative care and early return to normal limb function

Answer 11

Retrospective, 4 dog, 3D cutting/reduction guides and AM titanium plate All limbs corrected < 3.5 - 7.5 degrees of the pre-planned correction No complications were encountered. Medial plate added in 2 cases > surgeons perceived construct stiffness. simplifies intraoperative surgical decision-making good outcome in 4/4 with partially compensated biapical deformity by correction of distal CORA only

Answer 12

The trigonometric principles for the execution of neutral, closing and opening spherical osteotomies were explored in silico.

Answer 13

Computer-Assisted Surgery Using 3D Printed Saw Guides for Acute Correction, 5 dogs. 5 limbs > no complications. 1 > re-operated poorly resolved rotational component 1> required additional stabilisation due to screw loosening encouraging results, accurate correction of rotational deformity was problematic 2/5 lameness > preexisting joint deterioration. computer-assisted surgery overcomes inaccuracy translating the rehearsal surgery to the patient

Answer 14

influence of carprofen on bone healing in 18 dogs. Randomized controlled experimental study. Bone healing: rads 4 and 8 weeks + post-mortem biomechanical testing short-term (2wks) did not delay radiographic healing; long-term (8 weeks) affected biomechanical strength and radiographic healing of the tibial osteotomy. RUST > fracture healing assessment and has shown high intraobserver reliability Early elevation in PGE is consistent with a role in bone healing

Answer 15

CT-methodology for correction of femoral and tibial torsional deformities - for correction of patellar luxation - femur: external torsion = FTA <20°, internal torsion = FTA >35° tibia: external torsion = TTA < -10°, internal torsion = TTA >2° - calculation of cortical arc length: 2πr [CTA/360]

Answer 16

Accuracy of aLDFA measurement by caudocranial radiographs does not demonstrate sufficient accuracy when compared to CT There is value in radiographic measurements being used as a screening test to decide that gross deformity is not present or if further testing is indicated

Answer 17

6 dogs Patient-specific 3-D–printed osteotomy, reduction, and compression guides can provide effective assistance allowing accurate correction of tibial deformities. Their use yields good clinical outcomes in small-breed dogs

Answer 18

Three osteotomies tested (n = 8/group) were: (1) uniplanar 30 frontal plane wedge ostectomy, (2) oblique plane (30 frontal, 15 sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30 frontal, 15 sagittal, and 30 external). 84% of 3D PSG osteotomies were within 5 deviance from the target compared to 50% of freehand osteotomies as the complexity of the desired osteotomy increases, the guides become more critical