Transarticular elastic external skeletal fixator correction of a stifle rotational deformity and patellar luxation in a dog

OBJECTIVE

To report the preoperative evaluation, treatment with transarticular elastic external skeletal fixation (ESF), and outcome of a dog with bilateral medial patellar luxation (MPL) and stifle rotational deformity.

ANIMAL

One nonambulatory, 2.5-month-old, 7.5-kg mixed-breed intact female dog.

STUDY DESIGN

Case report METHODS: Complex pelvic limb deformities were assessed with physical examination and computed tomography (CT) and characterized as bilateral grade 4 MPL and 90° internal rotation of the tibia in relation to the femur. Three-dimensional imaging and bone models were used to quantify the deformity and rehearse surgical correction. Transarticular elastic chains between ESF pins in the femur and tibia were used to gradually correct stifle rotational malalignment on each pelvic limb. Soft tissue releases, imbrication, and a transphyseal staple were used to correct the patellar luxation (PL) and femoral varus. The dog was reevaluated for 1 year postoperatively.

RESULTS

Short- and long-term management included intensive physical rehabilitation to increase pelvic limb strength and function. Surgical treatment resulted in resolution of the PL and neutral stifle alignment. The dog was able to ambulate with persistent decreased range of motion of the stifle.

CONCLUSION

Transarticular elastic chains and femoral physeal stapling improved the function of a dog with severe bone deformities and PL in a growing dog.

Application of computed tomography and stereolithography to correct a complex angular and torsional limb deformity in a donkey

OBJECTIVE

To report the evaluation, surgical planning, and outcome for correction of a complex limb deformity in the tibia of a donkey using computed tomographic (CT) imaging and a 3D bone model.

STUDY DESIGN

Case report.

ANIMALS

A 1.5-year-old, 110 kg donkey colt with an angular and torsional deformity of the right pelvic limb.

METHODS

Findings on physical examimation included a severe, complex deformity of the right pelvic limb that substantially impeded ambulation. Both hind limbs were imaged via CT, and imaging software was used to characterize the bone deformity. A custom stereolithographic bone model was printed for preoperative planning and rehersal of the surgery. A closing wedge ostectomy with de-rotation of the tibia was stabilized with 2 precontoured 3.5-mm locking compression plates. Clinical follow-up was available for 3.5 years postoperatively.

RESULTS

CT allowed characterization of the angular and torsional bone deformity of the right tibia. A custom bone model facilitated surgical planning and rehearsal of the procedure. Tibial corrective ostectomy was performed without complication. Postoperative management included physical rehabilitation to help restore muscular function and pelvic limb mechanics. Short-term and long-term follow-up confirmed bone healing and excellent clinical function.

CONCLUSION

CT imaging and stereolithography facilitated the evaluation and surgical planning of a complex limb deformity. This combination of techniques may improve the accuracy of the surgeons' evaluation of complex bone deformities in large animals, shorten operating times, and improve outcomes.