AN INSIGHT INTO NON-UNION OF ADULT LONG BONE FRACTURES
Long bone fractures are the commonly encountered cases in orthopaedic practice. The working age groups (25-55 years) are the most affected and unless fracture heals (union) optimally restoring the normal function patients may have significant disability. Fractures when treated either by nonsurgical or surgical methods sometimes end up in non-union (bone does not heal). The cause is multifactorial. Unless surgically intervened, they don’t end up in union and cause a significant disability to the patient. When recognised on time and adequately treated these patients can have a normal union and get back to functional level.
Non-union – The end nobody wants
When a fractured long bone fails to unite in its stipulated time, we call it a non-union. Currently, majority of the fractures are offered surgery in view of the advanced and safe surgical options available and surgery in many case scenarios helps in early rehabilitation and return to function. But not all stories have a happy ending and not all fractures unite.
- Fracture related: (a) Open fractures (b) Fractures with bone loss (c) Fractures in areas with a precarious blood supply
- Surgery related: (a) Unstable fixations (b) Improper bone to bone contact (c) Infections (d) Extensive soft tissue stripping
- Patient related: (a) Smoking (b) Endocrinal problems (c) In select cases non-compliance of instructions
- Infection: Single most important cause. Extremely difficult to treat.
Note: Certain regions may take a longer than usual time to unite in view of anatomical peculiarities and these should be kept in mind before intervening. Fractured Bone unites by callus (new bone at and around fractured ends) formation. The blood supply (biological) and method of fixation (mechanical) plays an important role in this process. The usual time for the union to occur is 3 to 6 months. These slightly vary depending on patient and fracture factors but most fractures tend to unite by 6 months. The proper balance between biology and mechanics is the key for successful outcome of fracture fixation.
Arbeitsgemeinschaft für Osteosynthesefragen (German for “Association for the Study of Internal Fixation”) or AO has defined non-union if fracture doesn’t unite by 6-8 months (in some regions it is even earlier). Unless 6 months have passed, we don’t call a fracture to be in non-union. Exceptions are neck of femur and scaphoid where we diagnose as non-union in 3 months.
There are 2 basic types of non-unions.
- Hypertrophic (vascular) type
- Atrophic (less vascular) type
Hypertrophic: Usually the callus formation is not at fault, but the stability is at fault.
Atrophic: Usually the callus formation is at fault and the bone ends resorb gradually.
How do patients present?
Persistent pain which might vary in severity but is usually persistent and might occur at rest as well. Difficulty in using the extremity. Can present with deformity. Examination in some cases reveals, tenderness at the fracture site and abnormal mobility. Sometimes present with implant breakage. In infected non-union, signs of infection like, fever, discharging sinus etc. can be seen.
How do we evaluate?
Serial X-rays are the cornerstone which give us an idea on the progression of union. A visible gap at the fracture site and signs of implant fatigue or failure can be seen. Sometimes we need CT scans as well. Laboratory tests are ordered to assess on infection.
How do we treat?
Varied options depending on the type and severity of nonunion.
- Bone grafting: In atrophic non-union when small gaps are present with a stable implant. It is rarely done in isolation. Usually done in conjunction with fixation. We most commonly employ autologous (pts own) iliac crest grafts.
- Revision fixation with a stable implant: In hypertrophic non-union this is the commonly employed option. The unstable nail or plate is revised to a much stable construct.
- Revision fixation + Bone grafting: Most common treatment strategy. In most of the non-union especially atrophic type with implant failures and in some hypertrophic types as well.
- Augmentation + grafting: In atrophic variety with a stable implant an additional implant along with bone grafting can be done
- Ilizarov / LRS: These are external fixators. Usually in infected non-union this is employed. An excellent choice. Can be done for aseptic non-unions as well when skin condition doesn’t permit internal fixation or when the anatomical region is favourable for its application.
- Amputation: In non-responsive infected non-union this is an option. In some scenarios where multiple procedures have already been tried without much benefit sometimes we have to consider amputation. To conclude, the ultimate goal in non-union is union. When addressed in time patient can regain his pre-injury function. Normal pre-injury function is sometimes not possible especially so in chronic cases but union definitely helps to improve function and can be a game-changer for the patient.
MS (Ortho), MCh (Ortho), FCJR (Germany) HOD & Chief Orthopaedic and Joints Replacement Surgeon