Non Union

- See: 
         - Humeral Fracture Non Union 
         - Tibial Non Unions 
         - Femoral Shaft Non Union 
 
- Discussion: 
    - see bone healing and bone blood supply
    - definition: fracture that lacks potential to heal without further intervention
           - frx of shaft of long bone should not be considered nonunion until at least 6 months post injury, esp treatment was
                    complicated by infection; 
           - FDA: 9 months elapsed time with no healing progress for 3 months
           - in contrast, a central fracture of the femoral neck can sometimes be defined as a non union after only 3 months; 
    - in established non union, sclerosis develops around the bone ends and medullary canals are sealed off; 
    - bone ends are joined by fibrous tissue;
    - final stage of a nonunited fracture is formation of pseudoarthrosis (see pseudoarthrosis of tibia);
    - Risk Factors:
           - Causative factors of fracture nonunion: the proportions of mechanical, biological, patient-dependent, and patient-independent factors.
           - NSAIDS;
           - smoking
                 - references:
                        - Cigarette smoking increases complications following fracture: a systematic review.
                        - Dioxin Exposure Impairs BMP-2-Mediated Spinal Fusion in a Rat Arthrodesis Model
                        - Harmful lifestyles on orthopedic implantation surgery: a descriptive review on alcohol and tobacco use.
           - alcohol:
                 - Alcohol inhibits osteopontin-dependent transforming growth factor-β1 expression in human mesenchymal stem cells.
                 - Acute alcohol exposure impairs fracture healing and deregulates β-catenin signaling in the fracture callus.
                 - Induced epigenetic perturbations during the inflammatory stage of fracture healing
                 - Antioxidant therapy attenuates deficient bone fracture repair associated with binge alcohol exposure
                 -
Alcohol-induced bone loss and deficient bone repair
           - vitamin d deficiency
                 -
remember that vit D will not work without vitamin K (green salads or multivitamin)
                 - Nonunion of a distal tibial stress fracture associated with vitamin D deficiency: a case report.
           - thyroid imbalance:
                  - Metabolic and Endocrine Abnormalities in Patients With Nonunions.
           - hyperparathyroidism
                  - Primary hyperparathyroidism presenting as delayed fracture union 
           - infection: upto 30% of non union patients will have unexpected positive OR cultures;
                  - references:
                          - A single stage treatment protocol for presumptive aseptic diaphyseal nonunions: A review of outcomes.
                          - Can we trust intraoperative culture results in nonunions?

    - radiographic findings supporting non union:
           - consider 45 deg oblique views and stress views for maximal diagnostic potential
           - absence of bone crossing the fracture site (bridging trabeculae)
           - sclerotic fracture edges
           - persistent fracture lines (true union shows 4 healed cortices on the AP and Lateral views)
           - lack of evidence of progressive change toward union on serial xray
           - failing or broken implants
           - progressive deformity
           - lack of callus (most unreliable finding)
                   - callus formation is expected in IM nail
                   - callus formation is not expected with plate fixation;
           - ref: Classification of non-union.



- Types of Nonunions:

    - Hypervascular or Hypertrophic: (horse hoof)
    - Oligotrophic non unions:

            - these are not hypertrophic, and callus is absent;
            - they typically occur after major displacement of frx, distraction of fragments, or internal fixation w/o accurate apposition of fragments; 
            - has an intact blood supply
            - demonstrates radiotracer uptake on radionuclide scans
            - has inadequate healing response
    - Avascular or Atrophic:
            - ends of the fragments have become osteoporotic and atrophic; 
            - the non union is inert and incapable of biologic reaction; 
            - will have cold bone scan;
            - there is poor blood supply to the ends of the fragments;
            - these are typically seen in tibial frx treated by plate & screws;
            - are usually final result when intermediate fragments are missing & scar tissue that lacks osteogenic potential is left in their place; 
            - radiographs may show eburnated, osteopenic, and/or sclerotic bone ends
            - management:  open decortication must be carried out, and cancellous bone grafts should be added;
            - ref: Human atrophic fracture non-unions are not avascular.
    - Comminuted Nonunions:
            - these are characterized by the presence of one or more intermediate fragments that are necrotic;
            - typically these nonunions result in the breakage of any plate used in stabilizing the acute fracture;
    - Defect non unions;
            - these are characterized by the loss of a fragment of the diaphysis of a bone; 
            - ends of the fragments are viable, but union across the defect is impossible;
            - as time passes the ends of the fragments become atrophic;
            - these non unions occur after open fractures, sequestration in osteomyelitis, and resection of tumors; 
     - Infected tibial nonunion:

- Management with Bone Grafting:
     -
bone graft menu:
             - Judet decortication and compression plate fixation of long bone non-union: Is bone graft necessary?
     - synthes reamer aspirator
             - Reamer-irrigator-aspirator bone graft and bi Masquelet technique for segmental bone defect nonunions: a review of 25 cases.
             - Treatment of large segmental bone defects with reamer-irrigator-aspirator bone graft: technique and case series
             - Treatment of recalcitrant, multiply operated tibial nonunions with the RIA graft and rh-BMP2 using intramedullary nails
     - Masquelet technique
     -
BMPs 
     - references:
              - Application of recombinant BMP-7 on persistent upper and lower limb non-unions. 
              - Application of rhBMP-7 and platelet-rich plasma in the treatment of long bone non-unions: a prospective randomised clinical study on 120 patients.


Treatment of nonunion in neglected long bone shaft fractures by osteoperiosteal decortication.

Vascularized fibular grafts in the treatment of osteomyelitis and infected nonunion

Technique to Prepare the Bed for Autologous Bone Grafting in Nonunion Surgery



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, June 30, 2016 7:25 am