Pantarsal Arthrodesis

Pantarsal arthrodesis is surgical fusion of the ankle joint (tarsus). The most common reasons to do this operation are fractures of the tarsus (ankle), instability of the tarsus, pain, inflammation, chronic arthritis of the joint, or osteochondrosis dissecans of the talus bone. In all cases it is done when no better treatment option exists, i.e. rest and pain-killers have been tried and the outcome is not satisfactory. This surgery is the definitive solution for such dogs, is a “salvage” surgery and is not reversible — it is typically performed when all other treatment options have been exhausted or are thought not to be suitable.

Pantarsal arthrodesis is the definitive treatment option when other approaches are not suitable. Other options to consider include:

• Conservative management — exercise restriction and pain-killer anti-inflammatory drugs to control the problem as best as possible. Usually the underlying problem is not going to get better by itself and will likely get worse with time, but if your dog is coping well with this, it is a reasonable option.
• A brace for the tarsal joint — to help support the joint and limit instability and pain. These can work well in some dogs, but not so well in others; owners can find them fiddly, they may not fit well, can slip and cause rub sores, and some dogs do not tolerate them. A good brace is expensive and may not work as well as hoped for.

Outcome after pantarsal arthrodesis is expected to be excellent to extremely good, with normal to near normal limb function expected. A subtle mechanical lameness is permanent as the tarsus joint can no longer flex and extend.

All surgical procedures have the potential for complications. One very serious complication is that the skin on the inner and under-side of the foot can die back, creating an open wound, infection and exposure of the plate; this is called plantar tarsal necrosis. It can take weeks to months of intensive wound treatment to resolve, and in the worst case scenario plate removal (if the bone is sufficiently healed) or amputation may have to be considered. The reported incidence of this complication is 33%, but in our experience it is less than 10% and probably less than 5%.

Another complication is infection. Of those dogs that get infected, 50% respond positively to antibiotics and resolve completely; the other 50% are more problematic and may need long courses of antibiotics or implant removal, which can then expose the arthrodesis site to late failure, although this is very unlikely. The absolute worst case scenario would be uncontrollable infection eventually necessitating amputation, but this would be extremely rare.