Bones that do not heal after fracture are called nonunions or pseudarthrosis. Pseudarthrosis means false joint because the unhealed area of the bone has motion like a joint. These usually occur after trauma or surgery and affect mostly adults. A special kind of pseudarthrosis occurs in children without trauma; the bone fractures spontaneously. This is called congenital pseudarthrosis and occurs mostly in the tibia and forearm. The subject of congenital pseudarthrosis of the tibia is addressed separately from the subject of nonunion related to fractures or surgery.
The treatment of a nonunion depends on many factors.
If the nonunion is infected, it usually requires removing the dead infected bone and growing back healthy bone by distraction osteogenesis (the limb lengthening process). This can be accomplished by acutely (all at once) shortening the limb to eliminate the bone defect and then lengthening the bone at an alternative site, as described for limb lengthening. Alternatively, we can use a special technique called bone transport with which the defect is shortened at the same rate as the limb is lengthened, thereby not changing the length of the limb at any time. Both shortening with re-lengthening and bone transport result in a limb that is restored to equal length and normal alignment and that is solidly healed. It is sometimes necessary to insert a bone graft (the patient's own bone harvested from the pelvis) at the old nonunion site as part of these treatments.
If the nonunion is not infected, it can be classified as stiff or mobile and as hypertrophic or atrophic. The mobility of the nonunion is assessed by examination of the bone and observing whether the unhealed area moves much in response to manipulation. This is a simple, nonpainful test. If the unhealed area moves a lot, it is called mobile, whereas if it barely moves, it is called stiff. Based on radiographs, we classify nonunions regarding whether they show evidence of being hypertrophic (trying to heal) by making new bone versus whether they show no evidence of bone healing and even show indications of atrophy (withering away of the bone ends). Usually, hypertrophic nonunions are stiff and atrophic nonunions are mobile. There are three types of treatment to consider: distraction of the nonunion, compression of the nonunion, and bone grafting of the nonunion.
Distraction of the nonunion involves the application of an external fixator and gradual lengthening of the bone through the nonunion. This is a very successful treatment and has the advantage of not requiring any open surgery at the nonunion site (90% achieve union without bone graft).
Compression of the nonunion site (squeezing the bone ends together) is the other way to treat the hypertrophic stiff nonunion. It is also a good method for treatment of the hypertrophic mobile nonunion. Compression of the nonunion is achieved by the application of an external fixator or by means of internal fixation (plates, screws, and rods). Atrophic mobile nonunions usually require open treatment of the nonunion site, with removal of any dead bone and reshaping of the narrowed bone ends so that good bone contact can be achieved by compressing two horizontal surfaces. It is essential to add a bone graft to the nonunion site. The bone is usually obtained by taking small chips from the inside of the pelvic bone, either in the front or back of the pelvis. This does not cause any harm at the donor site.
Bone grafting of the nonunion site can be combined with internal or external fixation. Bone grafting is usually avoided when there is active infection. It can be performed later as a separate procedure after the infection is eliminated.
Nonunions are bones that don't heal. And as one patient at the Rubin Institute
for Advanced Orthopedics found out, it can be a painful, debilitating ordeal.
But through the skills of orthopedic surgeon Janet Conway, M.D., at the Rubin
Institute, his nonunion was successfully treated.