LImb Deformity | DAAvetcare

Angular Limb Deformity

Deformities of the long bone axis (angular, torsional, or combined) are malalignment of the long bone resulting in mechanical lameness, pain, and abnormal posture.

Angular Limb Deformity can be secondary to congenital malformations, the trauma of the growth plates, nutritional imbalance, and fractures healing in malunion.

The pathology is over-represented in chondrodystrophic breed dogs such as Basset Hound, English Bulldog, French Bulldog, Shih Tzu, Beagle, Pembroke, Corgi, Pug, Maltese, and Lhasa Apso.

Diagnosis

Limb deformity is one of the most complex causes of lameness in dogs. The diagnosis is based on clinical examination and radiographic imaging or CT scan.

Radiographic examination is used to measure the centre of rotation called CORA. The CORA method requires orthogonal radiographic views to evaluate joint orientation and bone axes; these are marked by lines passing through predefine landmarks and are used to estimate the degree of deformity. The intersecting angles of these lines are measured in the interesting point (CORA) to pre-plan the surgery (centre of the osteotomy and angulation correction axes).

3D printing models and customized implant based on CT scan studies are becoming more desirable options for the orthopaedic vet because they allow training on plastic models before performing the surgery on the patient.

A

Henry Macdougal Elbow R cra caud0000_edited.jpg

B

C

B

Henry Macdougal Elbow R lat str0000_edited.jpg

D

A and C, Radiographs of a "straight" leg, the carpus and the elbow joint are aligned on both XR.B and D, Radiographs of a limb affected by oblique biapical limb deformity, external deviation of the foot, and pro-curvatum radius.

Treatment

Surgery is the most commonly used treatment to correct the deformity and restore normal function of the leg. The surgery involves one or more osteotomies (cutting the bone in one or multiple places) and realignment of the bone axes. Once the bone is aligned, this is fixed by metallic implants (External Skeletal Fixators (ESF) or Plates and Screws).

ESF are less invasive than plates and can be used to correct CORA very close to the joint line. However, their post-operative care is more demanding due to the presence of the frame. Recurrent rechecks examination are required to assess pin loosening, pin discharge, infections and integrity of the frame. Substantial care of the apparatus on daily basis is required to avoid frame breakage.

Plates and screws are more technically demanding due to appropriate plate contouring during the surgery. However, they have a much easier post-operative care because of the internal position of the implants, and they guarantee an earlier return to function due to the stiffness of the construct.