Brian Solberg, MD - Non Union

Non union of the forearm (R) and Elbow (L)

Failure of the bone to unite after a fracture is referred to as a non union. This can be a very frustrating problem for patients and doctors. Most patients that I treat also suffer from Depression, understandably, and I usually recommend they have professional treatment of their Depression in addition to treating the non-union. My evaluation of non-unions focuses on the root cause of the problem which is classified in one of three categories: insufficient fixation (stability) which results in a hypertrophic non-union, insufficient biology (severe soft tissue damage) which results in an atrophic non union or infection which results in an infected non union. Determining the root cause is the key to getting the bone to heal. Smoking is much more common in patients with non-unions and a requirement for surgical treatment of the non-union is cessation of tobacco use. If a patient is smoking, their risk of failure to heal is about 2-3 times higher and I consider this a contraindication (reason not to do surgery) to non union repair. I most instances surgery to revise the fixation or to improve the local tissue biology is necessary and healing of non unions, especially in the lower extremity, is a slow process.

Bone Grafts, BMP's and Bone graft substitues

The use of bone grafts, bone graft substitutes and bone morphogenic protiens is a large are of controvery in orthopaedics. Bone graft refers to bone tissue which is transplanted into are area of the non union to stimulate healing. There are two types: Autogenous and Allograft. The purpose of using bone graft in non union repair is to deliver pluri-potential stem cells which can form new bone in the area on non healing. Autogenous bone graft refers to using a patients' own bone. Allograft refers to cadaveric bone which has been processed and freeze dried or frozen. Since the allograft is devoid of any active pluri-potential stem cells, its use in non union repair very limited and it does not stimulate new bone formation. For the purposes of non-union surgery, autogenous bone graft is the only type which can lead to new bone formation as it contains large numbers of stem cells and high concentrations of BMP's (see below). I routinely use autogenous bone graft for oligotrophic or atrophic non unions.

BMP's or bone morphogenic protiens are substances that stimulate pluri-potential stem cells to form bone. They are very powerful tools that can aid reconstruction in some cases. However, in the absence of good biology and stem cells, they are of limited benefit. I use BMP's in non union cases in which autogenous bone grafting has failed to unite the fracture or in cases in which there is segmental bone loss with a gap of missing bone of 1" or more.

Bone graft substitutes are agents which are usually derived from bone and have some BMP activity but no living stem cells. They can be used as graft expanders (a material that combines with autograft to give more volume) but are not particularly useful as stand alone agents.