1、General Principles in the Assessment and Treatment of Nonunions,Hobie Summers, MD and Daniel S. Chan, MD Revised April 2011Previous Authors: Peter Cole, MD; March 2004Matthew J. Weresh, MD; Revised August 2006,Definitions,Nonunion: (somewhat arbitrary) A fracture that has not and is not going to hea
2、l Delayed union: A fracture that requires more time than usual to heal Shows progression over time,Definitions,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 (FDA 1986)Not pragmatic Prolonged morbidity Narc
3、otic abuse Work-related and/or emotional impairment,Definitions (pragmatic),Nonunion: A fracture that has no potential to heal without further intervention,“The designation of a delayed union or nonunion is currently made when the surgeon believes the fracture has little or no potential to heal.”Don
4、ald Wiss M.D. & William Stetson M.D.Journal American and Orthopedic Surgery 1996,Classification,Hypertrophic Oligotrophic Atrophic = Avascular Pseudarthrosis Weber and Cech, 1976,Hypertrophic,Vascularized Callus formation present on x-ray Elephants foot - abundant callus Horses hoof - less abundant
5、callusTypically only needs stability to consolidate!,Oligotrophic,Some/minimal callus on x-ray Not an aggressive healing response, but not completely void of biologic activity Vascularity is present on bone scan,Atrophic,No evidence of callous formation on x-ray Ischemic or cold on bone scan,Pseudar
6、throsis,Typically has adequate vascularity Excessive motion/instability False joint forms over significant time,Hypertrophic (elephant foot),Hypertrophic (horse hoof),Oligotrophic or atrophic,Classification of Nonunions,Important factors for consideration Biologic and Mechanical environment Presence
7、 or absence of infection Septic vs Aseptic Vascularity of fracture site Stability mechanical environment Deformity Bone involved,Etiology of Nonunion,Host factors Fracture/Injury factors Initial treatment of injury factorsComplicating factor = Infection,Etiology of Nonunion Host Factors,Smoking Diab
8、etes/Endocrinopathy Thyroid/ parathyroid disorders, hypogonadism testosterone deficiency, Vit D deficiency, others Malnutrition Medications Steroids, Chemotherapy, Bispohosphonates Bone quality, vascular status Balance, compliance with weight bearing restrictions Psychiatric conditions, dementia,Smo
9、king,Decreases peripheral oxygen tension Dampens peripheral blood flow Well documented difficulties in wound healing in patients who smokeSchmite, M.A. e.t. al. Corr 1999Jensen J.A. e.t. al. Arch Surg 1991,Smoking vs. Fracture Healing,Most information is anecdotal and retrospective No prospective ra
10、ndomized studies on humans Retrospective studies show time to union Higher infection and nonunion rates More basic science studies concerning nicotine effects are currently underway,Schmitz, M.A. e.t.al. CORR 1999 McKee et al, JOT 2003 Struijs et al, JOT 2007 Chen et al, Int Orthop 2011,Diabetes (Ne
11、uropathic Fractures),Best studied in ankle and pilon fractures: Complicated diabetics those with end organ disease neuropathy, PVD, renal dysfunction Increased rates of infection and soft tissue complications Increased rates of nonunion, time to union significantly longer Prolonged NWB required Inab
12、ility to control response to trauma can result in hyperemia, osteopenia, and osteoclastic bone resorption Charcot arthropathy,Kline et al , Foot Ankle Int. 2009 Wukick et al, JBJS, 2008,Malnutrition,Adequate protein and energy is required for wound healing Screening test: serum albumin total lymphoc
13、yte count Albumin less than 3.5 and lymphocytes less than 1,500 cells/ml is significantSeltzer et.al. JPEN 1981,Etiology of Nonunion Fracture/Injury Factors,High energy injury Fracture mechanism MVC vs fall from standing Open or closed fracture Bone loss Soft tissue injury Bone involved and anatomic
14、 locationOpen tibial shaft fx with bone loss vs closed nondisplaced proximal humerus fx,Think about the personality of the fracture!,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 ischemi
15、a,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 nonunionGustilo et.al.Jol 1984Widenfalk et.al.Injury 1979Edwards et.al. Ortho Trans 1979Velazco et.al. TBJS 1983,Tscherne Soft
16、 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,Tscherne Classification: closed fractures,Grade 0: Soft tiss
17、ue damage is absent or negligibleGrade I: Superficial abrasion or contusion caused by fragment pressure from withinGrade II: Deep, contaminated abrasion associated with localized skin or muscle contusion from direct traumaGrade III: Skin extensively contused or crushed, muscle damage may be severe.
18、Subcutaneous avulsion, possible artery injury, compartment syndrome,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,Etiol
19、ogy: Surgeon,Excessive soft tissue stripping Improper or unstable fixation Absolute stability Gap due to distraction or poor reduction Relative stability Excessive motion,Etiology of Nonunion Initial Treatment Factors,Nonunion may occur after completely appropriate treatment of a fracture, or after
20、less than appropriate treatment Was appropriate management performed initially? Operative vs non-operative? Was the stability achieved initially appropriate? Consider: Bone and anatomic location (shaft vs metaphysis) Patient host status, compliance with care,Etiology of Nonunion Initial Treatment Fa
21、ctors,After operative treatment Was the appropriate implant and technique employed? (Fixation strategy) Relative vs absolute stability? Direct vs indirect reduction? Implant size/length, number of screws, locking vs conventional Location of incisions. Signs of poor dissection? Iatrogenic soft tissue
22、 disruption, devascularization of bone,Etiology of Nonunion Initial Treatment Factors,Is the current construct too flexible or too stiff? Implant too short? Bridge plating of a simple pattern with lack of compression? Why did the current treatment fail? Understanding the mode of failure for the init
23、ial procedure helps with planning the nonunion surgery,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 Open diaphyseal tibia fractures are the classic example with high
24、 rates of nonunion throughout the literature,Infection,“Of all prognostic factors in tibia fracture care, that implying the worst prognosis was infection”Nicoll E.A. CORR 1974,Infection,May be obvious Open draining wounds, erythema, inadequate soft tissue coverage Subclinical is more difficult High
25、index of suspicion ESR, CRP may indicate infection and provide baseline values to follow after debridement and antibiotic therapy,Infection,Must be dealt with Debridement, debridement, debridement Multiple cultures. Identify the bacteria Infectious disease consult is helpful Infected bone requires s
26、tability to resolve infection May achieve union in the presence of infection with appropriate treatment,Patient Evaluation,History of injury and prior treatment Medical history and co-morbidities Physical examination Including deformity! Imaging modalities Patient needs, goals, expectations,Patient
27、Evaluation History of Injury,Date and nature of original injury (high or low energy) Open or closed injury? Number of prior surgical procedures History of drainage or wound healing difficulties? Prior infection? Identify antibiotics used and bacteria cultured (if possible) Written timeline in comple
28、x cases Current symptoms pain, deformity, motion problems, chronic drainage Ability to work and perform ADLs,Patient Evaluation Medical History,Diabetes, endocrinopathies, vit D, etc Physiologic age co-morbidities Heart disease, COPD, kidney/liver disease Nutrition Smoking Medications Ambulatory/fun
29、ctional status now and prior to original injury,Patient Evaluation Physical Exam,Appearance of limb Color, skin quality, prior incisions, skin grafts Erythema or drainage Range of motion of all joints Pain location and contributing factors Strength, ability to bear weight Vascular status and sensati
30、on (complete neurovascular exam) Deformity Clinically = Length, alignment, AND rotation,Patient Evaluation - Imaging,Any injury-related imaging available plain film and CT Serial plain radiographs from injury to present are extremely helpful (hard to get) Most current imaging orthogonal x-rays, typi
31、cally diagnostic for nonunion Healing of 3 out of 4 cortices without pain is typically considered union. Obliques may be helpful for radiographic diagnosis of nonunion CT can be helpful but metal artifact can make it difficult,Patient Evaluation Imaging Tomography,Linear tomograms Helpful if metalli
32、c hardware present Helps to identify persistent fracture line in: Hyptrophic nonunions in which x-rays are not diagnostic and pain persists at fracture site CT and MRI are replacing linear tomography Still a good option if available at your institution,Radionuclide Scanning,Technetium - 99 diphospho
33、nate Detects repairable process in bone ( not specific) Gallium - 67 citrate Accumulates at site of inflammation (not specific) Sequential technetium or gallium scintigraphy Only 50-60% accuracy in subclinical ostoemyelitisEsterhai et.al. J Ortho Res. 1985Smith MA et.al. JBJS Br 1987,Indium III - La
34、beled 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 infectionNepola JV e.t. al. JBJS 1993Merkel KD e.t. al. JBJS 1985,MRI,Abnormal m
35、arrow 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 ImgModic MT et.al. Rad. Clin Nur Am 1986Mason MD et.al. Rad. 1989,Patient Evaluation Goals &
36、 Expectations,What are the patients goals and needs? Household ambulation vs marathon runner Pain relief expectations Range of motion expectations Long standing nonunions may have stiff adjacent joints Risks to neurovascular structures (radial nerve in humerus nonunion),Treatment,Nonoperative Operat
37、ive,Nonoperative,Electrical stimulation Ultrasound Extracorporeal shock wave therapy,Electrical Stimulation,Applied mechanical stress on bone generates electrical potentials Compression = electronegative potentials = bone formation Tension = electropositive potentials = bone resorption Basic science
38、 suggests e-stim upregulates TGF- and BMPs suggesting osteoinduction,Three Modalities of Electric bone Growth Stimulators,1. Direct current - implantation of cathode in bone and anode on skin 2. Inductive coupling pulsed electromagnetic field with device on skin 3. Capacitive coupling - electrodes p
39、laced on skin, alternating current Conflicting and inconclusive evidence,Mollon et al, JBJS 2008,Contraindication to Electric Stimulation,Synovial pseudoarthrosis Electric stimulation does not address associated problems of angulation, malrotation and shortening deformity!,Unanswered Questions,When
40、is electric stimulation indicated? Which fracture types are indicated? What are the efficacy rates? What time after injury is best for application? Ryaby JT Corr 1998,Ultrasound,Piezoelectric transducer generates an acoustic pressure wave Prospective randomized trial in nonunion population has not b
41、een done Some evidence to show faster healing in fresh fractures Evidence is moderate to poor in quality with conflicting results,Busse et al, BMJ 2009,Extracorporeal Shock Wave Therapy,Single impulse acoustic wave with a high amplitude and short wavelength. Microtrauma induced in bone thought to st
42、imulate neovascularization and cell differentiation Clinical studies are of a poor level and no strong evidence for use in nonunions is available,Biedermann et al, J Trauma 2003,Operative Treatment,Debridement and hardware removal Plate osteosynthesis Intramedullary nailing External fixation,Autogen
43、ous bone graft Bone marrow aspirate Allograft bone Demineralized bone matrix BMPs Platelet concentrates,Autogenous Bone Marrow Aspirate,Typically from the iliac crest Transplant osteoprogenitor and mesenchymal stem cells to nonunion site Osteoinductive, not osteoconductive Level III and IV studies a
44、vailable Positive correlation between number of progenitor cells in aspirate and amount of callous,Hernigou et al, JBJS 2005,BMPs,rhBMP-2 and rhBMP-7 have been shown to be equivalent to autologous iliac crest for delayed reconstruction of tibial bone defects May be a good alternative to ICBG for the
45、 management of nonunion Very expensive!,Jones et al, JBJS 2006 Friedlaender et al, JBJS 2001,rhBMP-2,rhBMP-2 inserted at the time of definitive wound closure for high grade (3A or 3B) open tibia fractures- unclear effect on re-operation and infection rates because literature conflicting Aro et al. J
46、BJS 2011 Swiontkowski et al. JBJS 2006 BESTT trial. JBJS 2002,Autogenous Bone Grafting,Considered the “gold standard” Osteoinductive - contain proteins and other factors promoting vascular ingrowth and healing Osteogenic contains viable osteoblasts, progenitor cells, mesenchymal stem cells Osteocond
47、uctive - contains a scaffolding for which new bone growth can occur,Surgical/Fixation Strategy,Define nonunion type Hyper-, oligo-, atrophic, or pseudarthrosis Fracture location diaphysis vs metaphysis Infected vs Aseptic Deformity? Patient/host factors Goals and expectations,Plate Osteosynthesis,Co
48、rrection of malalignment Osteotomy may be required, planning always required Compression in hypertrophic cases Immediate mobilization, likely NWB Requires adequate soft tissue coverage More dissection required for plating and osteotomy in deformity correction Bone graft as needed,Plate Osteosynthesi
49、s,Soft tissue and bony dissection are extremely important! Preserve periosteum and muscular attachment to bone Concept of “working window” Only expose the necessary amount of bone to do the case, maintain vascularity,Plate Osteosynthesis: Osteoperiosteal Decortication,Management of the bone Do not s
50、imply elevate the periosteum off the bone! Use a sharp chisel or osteotome to elevate an osteoperiosteal flap Sharp chisel and a mallet to take some good, vascularized bone with the periosteum Provides excellent environment for bone graft to produce callous as the elevated bone remains vascularized by the periosteum,
