Fusion surgery is frequently used to treat arthritic joints in the foot and ankle. With fusion surgery, the two sides of the joint are roughened with a burr or small chisel. Next, the two bones that make up the arthritic joint are screwed together. The foot and ankle are then immobilized with a cast. In the weeks and months following surgery, the body is “tricked” into thinking that there is a fracture present at the fusion site and heals this with bone. As such, the two bones become one and are considered “fused.” Because there is no longer an arthritic joint present, the pain is relieved.
If you are undergoing fusion surgery, your cooperation is essential in order to obtain a successful fusion. In approximately 10% of patients, the fusion does not “take.” That is, the two bones that were to be fused remain separate and do not unite. This is called a “non-union” and often results in a lack of pain relief from the surgery.
So what can you do? The most important thing is to follow your postoperative weight- bearing instructions. Most patients with fusion surgery are kept “non weight-bearing.” The reason is to prevent motion. Motion prevents the two bones from fusing. If you put weight on your foot after a fusion, this can lead to motion, even with the screws and cast. Also, if significant force is applied even just once, the screws that are used to hold the bones together can loosen. This will also lead to motion, and prevent the fusion from healing. Thus, it is essential to remain completely and strictly non weight-bearing if you are instructed to do so following your fusion surgery.
Along these lines, at some point you will be instructed to begin advancing your weight-bearing. This doesn’t mean that you should go ahead with unlimited walking. When a fusion heals, it initially heals with unorganized, or “woven”, bone. This is weaker bone that eventually becomes organized and structured into what is called “lamellar” bone. Lamellar bone is much stronger and considered to be mature bone. The process by which your fusion progresses from woven to lamellar bone is gradual. Some weight is needed to stimulate this process. However, too much weight can interfere with healing. How much weight is enough? Listen to your body and let your symptoms be your guide. If you have pain when you begin to walk on your fusion, you may be walking for too long or putting too much weight on the fusion. If so, you should walk less and put less weight on the fusion. You can then gradually increase from there. Finally, it is critical to avoid cigarette smoking while your fusion is healing. Cigarette smoke decreases healing. If a family member smokes, they should do so outside to minimize your exposure to second hand smoke.
In our practice, thousands of patients have undergone successful fusions. Patients enjoy pain relief and restored function. You play a critical role in your own healing process. Your cooperation and compliance with postoperative instructions is critical. Please, follow your weight-bearing instructions 100% of the time. Remember, it takes just one step to cause a nonunion. If you need practice with your crutches or walker, contact us and we will get you some extra help.