Proximal limb joint fusion (Shoulder, Stifle, Elbow)

In general, an arthrodesis is a salvage procedure, or an “end-stage” procedure, in order to preserve overall limb function. In humans, it is primarily used as a salvage procedure for failed primary surgical procedures, e.g., severe joint trauma, or failed arthroplasty. In small animals, it is used as a primary surgical procedure for hyperextension injuries of the antebrachial carpal joint; in addition, it is sometimes considered a primary option in OCD of the tarsus, or for severe trauma of the carpus/tarsus. These lower joints are excellent candidates for total joint fusion, as the majority of joint motion for the limb, which preserves the gait, occurs at the more proximal joints.

Arthrodesis of the proximal limbs is generally less well tolerated due to the restriction of total limb range of motion (ROM). Because of the more proximal positioning of joint immobility, advancement of the limb becomes problematic, as the foot (paw) can no longer clear the ground as the pendulum no longer shortens at the vertical position mid-stance of the swing phase of the gait, leading to an awkward gait pattern. In humans, the latter typically leads to the development of arthritis in the back and hip as a result of "double duty" trying to accommodate the lost motion at the knee. Although this may also occur in animals, I am unaware of any reports that document this issue.

An arthrodesis, regardless of the location it is performed, follows the general principles of: removal of articular cartilage; placement of bone graft (either within the previous joint space [or osteotomy] or around it, or both; application of rigid internal fixation (preferably with compression across the bone fragments); fusion at a functional the appropriate standing joint angle; +/- postoperative external coaptation. [...]