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General Principles in the Assessment and Treatment of Nonunions

General Principles in the Assessment and Treatment of Nonunions. Matthew J. Weresh, MD Original Author: Peter Cole, MD; March 2004 New Author: Matthew J. Weresh, MD; Revised August 2006. Definitions. Nonunion: A fracture that has not and is not going to heal

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General Principles in the Assessment and Treatment of Nonunions

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  1. General Principles in the Assessment and Treatment of Nonunions Matthew J. Weresh, MD Original Author: Peter Cole, MD; March 2004 New Author: Matthew J. Weresh, MD; Revised August 2006

  2. Definitions • Nonunion: A fracture that has not and is not going to heal • Delayed union: A fracture that requires more time than is usual and ordinary to heal

  3. Previous Definitions of Nonunion • Nonunion: A fracture that is a minimum of 9 months post occurrence and is not healed and has not shown radiographic progression for 3 months Orthopaedic Advisory Panel: Food & Drug Administration, 1986

  4. Waiting 9 months or more is often inappropriate: • Prolonged morbidity • Inability to return to work • Narcotic dependence • Emotional impairment

  5. Definition of nonunion should not limit or prevent appropriate and timely intervention • “The best treatment for nonunions is prevention” Sir John Charnley

  6. “The designation of a delayed union or nonunion is currently made when the surgeon believes the fracture has little or no potential to heal.” Donald Wiss M.D. & William Stetson M.D. Journal American and Orthopedic Surgery 1996

  7. Classification of Nonunions • Two important factors for consideration • (1) Presence or absence of infection • (2) Vascularity of fracture site

  8. Classification • (1) Hypertrophic • (2) Oligotrophic • (3) Avascular Weber and Cech, 1976

  9. Hypertrophic • Vascularized • Callus formation present on x-ray • Elephant foot - abundant callus • Horse hoof - less abundant callus (see diagram)

  10. Oligotrophic • No callus on x-ray • Vascularity is present on bone scan

  11. Avascular • Atrophic or similar to oligotrophic on x-ray • Ischemic or cold on bone scan

  12. Hypertrophic (elephant foot) Hypertrophic (horse hoof) Oligotrophic or atrophic

  13. Incidence of Nonunion Boyd et.al Connolly No. 842(1965) No.602 (1981) Tibia 35 % 62% Femur 19% 23% Humerus 17.5% 7% Forearm 15.5% 7% Clavicle 2% 1% *Increasing frequency of tibial nonunion over time

  14. Increasing relative incidence of tibial and femoral nonunion most likely secondary to improved limb salvage techniques

  15. Etiology of Nonunion: Systemic • Malnutrition • Diabetes (neurovascular) • Smoking

  16. Malnutrition • Adequate protein and energy is required for wound healing • Screening test: • serum albumin • total lymphocyte count • Albumin less than 3.5 and lymphocytes less than 1,500 cells/ml is significant Seltzer et.al. JPEN 1981

  17. Diabetes(Neuropathic Fractures) • Neuro arthropathy is not entirely the result of unprotected weight bearing on an insensate joint • Inability to control response to trauma can result in hyperemia, osteopenia, and osteoclastic bone resorption

  18. Neuropathic Fracture Nonunions • Treatment, conservative (bracing) and operative, are fought with complications • No currently accepted algorithm • Consider use of biphosphonates to decrease osteolytic response Shelby et.al. Diab. Med. 1994 Connolly J.F. and Csencsitz T.A. CORR #348 1998 Young e.t. al. Diab. Care 1995 McCormack R.G. e.t. al. JBJS 1998

  19. Smoking • Decreases peripheral oxygen tension • Dampens peripheral blood flow • Well documented difficulties in wound healing in patients who smoke Schmite, M.A. e.t. al. Corr 1999 Jensen J.A. e.t. al. Arch Surg 1991

  20. Smoking vs. Fracture Healing • Most information is anecdotal • No prospective randomize studies on humans • Retrospective studies show time to union • 69% delay in radiographic union with smoker (2 of 44 nonunions in smokers vs. 0 of 59 nonunion in nonsmokers) increased incidence of nonunion with smokers Schmitz, M.A. e.t.al. CORR 1999

  21. Etiology of Nonunion(Local Factors) • Infection • Energy of fracture mechanism • Mechanical factors of fracture configuration • Increased motion between fracture fragments • Inadequate fixation • Wolf’s Law - lack of physiologic stresses to bone • Anatomic location

  22. Infection “Of all prognostic factors in tibia fracture care, that implying the worst prognosis was infection” Nicoll E.A. CORR 1974

  23. The inflammatory response to bacteria at the site of the fracture disrupts callus, increases gap between fragments, and increases motion between fragments.

  24. Energy of Fracture Mechanism • Initial fracture displacement • Fracture pattern i.e: • comminution • bone loss • segmental patterns • Soft tissue disruption (vascularity and oxygen delivery)

  25. Initial Fracture Displacement Nicoll E.A., 705 cases, 1964 • Delayed union and nonunion were nearly three times as frequent in tibia fractures with moderate to severe displacement as compared to fractures with slight displacement.

  26. Fracture Pattern • Fracture patterns in higher energy injuries (i.e.: comminution, bone loss, or segmental patterns) have a higher degree of soft tissue and bone ischemia

  27. Soft Tissue Disruption • 1. Introgenic • 2. Traumatic

  28. Traumatic Soft Tissue Disruption • Incidence of nonunion is increased with open fractures • More severe open fracture (i.e. Gustillo III B vs Grade I) have higher incidence of nonunion Gustilo et.al.Jol 1984 Widenfalk et.al.Injury 1979 Edwards et.al. Ortho Trans 1979 Velazco et.al. TBJS 1983

  29. Introgenic • Excessive soft tissue dissection and periosteal stripping at time of previous fixation

  30. Tscherne Soft Tissue Classification • Not all high energy fractures are open fractures. This classification emphasizes the importance of viability of the soft tissue envelope at the zone of injury. Fractures with Soft Tissue Injuries Springer Verlag 1984

  31. Soft Tissue Classification • Grade 0: Soft tissue damage is absent or negligible • Grade I: Superficial abrasion or contusion caused by fragment pressure from within • Grade II: Deep, contaminated abrasion associated with localized skin or muscle contusion from direct trauma • Grade III: Skin extensively contused or crushed, muscle damage may be severe. Subcutaneous avulsion, possible artery injury, compartment syndrome

  32. Revascularization of ischemic bone fragments in fractures is derived from the soft tissue. If the soft tissue (skin, muscle, adipose) is ischemic, it must first recover prior to revascularizing the bone.E.A. Holden, JBJS 1972

  33. Mechanical Factors • Excessive motion at fracture secondary to poor fixation, failed fixation, or inadequate immobilization • Lack of physiologic mechanical stimulation to fracture area (i.e. nonweight bearing, fracture fixed in distraction, adynamic environment with external fixation)

  34. Anatomic Location of Fractures • Some areas of skeleton are at risk for nonunion due to anatomic vascular considerations i.e.: • Proximal 5th metatarsal, femoral neck, carpal scaphoid

  35. Diagnosis of Nonunion- History • Nature of original injury (high or low energy) • Previous open wounds of injury site • Pain present at fracture site • Symptoms of infection i.e. • Antalgic gait or decrease use secondary to pain • History of any drainage or wound healing difficulties

  36. Examination • Alignment • Deformity • Soft tissue integrity • Erythema, warm, drainage • Vascularity of limb • Pulses, transcutaneous oximetry • Stability at fracture site • Pain assessed during this portion of examination

  37. X-rays • AP, lateral, and oblique (45degree internal and 45 degree external) • In majority of cases, this is all that is required to confirm nonunion • Examination under fluoroscopy to check for motion can occasionally be helpful also

  38. Tomography • Linear tomograms • Helpful if metallic hardware present • Helps to identify persistent fracture line in: • Hyptrophic nonunions in which x-rays are not diagnostic and pain persists at fracture site • Computed tomography and MRI are replacing linear tomography if no hardware present

  39. Subclinical Undetected Infection • The main diagnostic dilemma in evaluation of nonunions

  40. Radionuclide Scanning • Technetium - 99 diphosphonate • Detects repairable process in bone ( not specific) • Gallium - 67 citrate • Accumulate at site of inflammation (not specific) • Sequential technetium or gallium scintigraphy • Only 50-60% accuracy in subclinical ostoemyelitis Esterhai et.al. J Ortho Res. 1985 Smith MA et.al. JBJS Br 1987

  41. Indium III - Labeled Leukocyte Scan • Good with acute osteomyelitis, but less effective in diagnosing chronic or subacute bone infections • Sensitivity 83-86%, specificity 84-86% • Technique is superior to technetium and gallium to identify infection Nepola JV e.t. al. JBJS 1993 Merkel KD e.t. al. JBJS 1985

  42. MRI • Abnormal marrow with increased signal on T2 and low signal on T1 • Can identify and follow sinus tacts and sequestrum • Mason study- diagnostic sensitivity of 100%, specificity 63%, accuracy 93% Berquist TH et.al. Magn Res Img Modic MT et.al. Rad. Clin Nur Am 1986 Mason MD et.al. Rad. 1989

  43. Tissue Biopsy • Antibiotic discontinued for 72 hours prior to biopsy • Multiple representative biopsy specimens should be obtained • Cultures sent for gram stain, aerobic, anerobic, fungal, and acid fast studies • Open biopsy techniques can be inconclusive due to problem of detecting bacteria protected by an external glycocalyx Gristina AG el.al Inst Con Lect 1990

  44. Treatment • Nonoperative • Operative

  45. Nonoperative • Ultrasound • Electric stimulator • Bone marrow injection

  46. Ultrasound • Ultrasound fracture stimulation devices have shown ability to increase callus response in fresh fractures (shortens time for visible callus on x-ray) • Prospective randomized trial in nonunion population has not been done • Use in nonunions remains theoretical Goodship & Kenwright JBJS 1985

  47. Electric Stimulation • Piezoelectric nature of bone - stress generated electric potentials exist in bone and are related to callus formation Fukada & Yasuda,J Phys Soc Jpn 1957 Busse H CAL e.t. al. Science 1962 • Electromagnetic fields influence vascularization of fibrocartilage, cell proliferation & matrix production Monograph Series,AAOS

  48. Three Modalities of Electric bone Growth Stimulators • 1. Direct current - percutaneous or implanted electrodes • 2. Electromagnetic stimulation - uses time varying magnetic fields (noninvasive) • 3. Capacitive coupling - uses electrodes placed on skin (noninvasive)

  49. Two Attempts at Well Controlled Double Blind (placebo) Studies on Nonunion Healing with Electric Stimulation • 1. Pulsed electromagnetic fields • Tibial delayed unions 16-32 weeks from injury • 45% united in active device group • 14% united in placebo group (P < 0.02) Sharrard JBJS e.t. al 1990 • 2. Capacitive coupling • 6 of 10 with active device healed • 0 of 11 with placebo device healed (P < 0.004) Scott G and King JBJS 1994

  50. Contraindication to Electric Stimulation • Synovial pseudoarthrosis • Electric stimulation does not address associated problems of angulation, malrotation and shortening

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