What Is Naviculocuneiform Fusion?
The naviculocuneiform (NC) joint is located in the middle of the foot. It consists of four bones: the tarsal navicular and the medial, middle, and lateral cuneiforms.
The main reason to perform NC joint fusion is to relieve pain related to arthritis. Arthritic joints in the midfoot typically occur after trauma to that area or as part of a collapsing foot arch. When a joint is arthritic, the cartilage has worn away and
the bony surfaces rub together, which causes pain. The goal of the fusion is to get the bones to heal together so the pain goes away. Sometimes patients whose arches have collapsed will have a deformity that requires NC fusion to correct it.
Diagnosis
You may notice pain on top of the foot with tight shoes or weightbearing activities. This pain can prevent you from being able to walk for any length of time. The pain usually is worst after you get up from resting or sitting. It can improve
slightly with walking but then gets worse with continued walking. Your foot and ankle orthopaedic surgeon may recommend weightbearing radiographs and advanced imaging such as a CT or MRI help to make the proper diagnosis.
Surgery should be avoided if you have any signs or symptoms of a bone or skin infection to the same foot or ankle as the planned procedure. An infection can prevent the bones from healing together and lead to more surgery in the future.
Smoking increases the risk of blood clots, wound healing problems, and the possibility the fusion won't heal. You should completely stop nicotine use at least one month before surgery and abstain until the fusion has healed. Surgery is not recommended if you are unable or unwilling to follow your surgeon's treatment plan.
Treatment
Depending on the general health of the patient and if there are other procedures planned to take place with the NC fusion, the procedure often is done on an outpatient basis. Patients are put to sleep with general anesthesia. A nerve block may also be offered.
This will make the operative foot and ankle numb and help with pain control after surgery.
Generally, your surgeon will make a single incision along the inside of the foot to gain access to the joint. After the joint is identified, they will remove the cartilage that remains on the bones, position the bones back in their correct location, and hold them in place with screws or a combination of plates and screws. The surgeon then closes the wounds with stitches or staples and places the patient into a well-padded splint. You will need to stay off the operative foot for 6-8 weeks.
Specific Techniques
During surgery, the surgeon opens the lining of the joint and evaluates the joint surfaces. More often than not, the top of the joint surface has been worn away while the bottom of the joint still has cartilage in place. After all of the cartilage has been
removed, holes are placed in the underlying bone to allow bleeding at the joint, which helps the bones heal together. Bone graft also may be used to help the bones heal together.
Recovery
Normally, patients are placed into a well-padded splint while in the operating room. Patients are asked to keep their dressings clean and dry at all times and to not remove the dressing unless instructed to do so by their foot and ankle orthopaedic surgeon.
The first two weeks after surgery usually are spent with the foot elevated to help decrease swelling. At around two weeks the stitches/staples are removed and X-rays are taken. Patients typically are placed into a cast or boot and remain non-weightbearing for another 4-6 weeks.
About 6-8 weeks after surgery, you will come out of the cast or boot and get X-rays to assess healing. If all looks good you can begin gradually putting weight on your foot. Physical therapy may be recommended to improve strength and range of motion of the foot and ankle. You may have residual swelling and periodic
discomfort in the year following surgery, but the majority of patients are back to normal activities in 4-6 months.
Risks and Complications
All surgeries come with possible complications, including the risks associated with anesthesia, infection, damage to nerves and blood vessels, and bleeding or blood clots.
Complications from this procedure can include delayed wound healing, infection, and delayed bone healing or no bone healing at all. All of these complications generally require further surgery to try and correct the problems. These complications are rare
but happen more frequently in diabetic patients and those who smoke.
After the bones grow together, will I still be able to walk or run?
In a normal foot, there is limited motion at these joints, so removing painful motion generally will not have any negative effect on your ability to walk or run.
A successful naviculocuneiform fusion should allow you to walk or run pain-free once you have recovered fully from the surgery.
Why do I need to be non-weightbearing for so long?
Typically, in a healthy non-smoking patient without diabetes, bones take 6-8 weeks to heal. Patients are asked to remain non-weightbearing for that period to prevent motion
between the bones that are trying to heal together. If there is too much motion between the bones, it can take longer for them to heal or they may not heal at all.
What if my bones do not heal together?
The term for this is nonunion. It is more common in patients who are diabetic or who smoke. Putting weight on the foot prior to the bones healing can cause a nonunion as well. If this
happens the patient will continue to have pain just like before surgery. A nonunion requires another surgery. More or bigger plates and screws can be tried the second time, and usually some form of bone graft is used to try and help the bones heal.
Original article by Nicholas Cheney, DO
Reviewers/Contributors: Jason Tartaglione, MD; Erik Freeland, DO
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