You are in: eMedicine Specialties > Orthopedic Surgery > KNEE Tibial NonunionsArticle Last Updated: Apr 9, 2004AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Minoo Patel, MBBS, MD, MS, FRACS, Senior Lecturer, Monash University; Consulting Adult/Pediatric Orthopedic Surgeon, Department of Orthopedic Surgery, Monash Medical Center, Australia Minoo Patel is a member of the following medical societies: American Academy of Orthopaedic Surgeons, AO Foundation, Australian Association of Surgeons, Australian Medical Association, Australian Orthopaedic Association, Orthopaedic Research Society, Orthopaedics Overseas, Pediatric Orthopaedic Society of North America, and Royal Australasian College of Surgeons Coauthor(s): James J McCarthy, MD, FAAOS, FAAP, Associate Professor, Consulting Orthopedic Surgeon, Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine and Public Health;; John Herzenberg, MD, FRCSC, Head of Pediatric Orthopedics, Co-director of International Center for Limb Lengthening, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore Editors: Charles T Mehlman, DO, MPH, Director, Musculoskeletal Outcomes Research, Associate Professor, Division of Pediatric Orthopedic Surgery, Cincinnati Children's Hospital Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Thomas M DeBerardino, MD, Director, John A Feagin, Jr, Sports Medicine Fellowship at West Point, Associate Professor of Orthopedic Surgery, Uniformed Services University of the Health Sciences and Keller Army Community Hospital; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Carlos J Lavernia, MD, FAAOS, Adjunct Clinical Professor, Department of Orthopedic Surgery, University of Miami School of Medicine; Medical Director, Orthopedic Institute at Mercy Hospital Author and Editor Disclosure Synonyms and related keywords: tibial delayed union, aseptic nonunion, infected nonunion, tibial fractures, fractures of the tibia, nonunions of the tibia, broken leg, leg fracture, delayed healing, hypertrophic nonunions, atrophic nonunions, normotrophic nonunions, long bone fractures INTRODUCTIONSection 2 of 12
  Tibial fractures can now be successfully treated in the majority of patients, yet nonunions of the tibia are not uncommon and may result in significant morbidity, require numerous operative procedures to treat, and leave the patient with functional deficits. The subcutaneous position of the tibia results in a greater incidence of open fractures and provides less soft tissue coverage, factors that produce a higher incidence of nonunion and infected nonunion. Although appropriate and prompt treatment is needed to successfully treat tibial injuries, the incidence of a nonunion is more closely related to the fracture characteristics than subsequent treatment. Establish realistic expectations of the outcome with the patient as early in the treatment course as possible, preferably prior to treatment intervention. FrequencyThe incidence of tibial nonunion is estimated to range from 2-10% of all tibial fractures. The incidence is greater with high-energy injuries and open fractures. EtiologyThe development of a nonunion in the tibia is most closely related to the type and degree of injury, but several factors may predispose a patient to a tibial nonunion. Many of these are related to the characteristics of the fracture, such as the degree of fracture comminution and bone loss, whether the fracture is open, and the degree of soft tissue injury. Subsequent complications, such as infection or compartment syndrome may play a roll (McQueen, 1996). The patient profile also contributes to the incidence of nonunion. Cigarette smoking is well documented to place the patient at a higher risk of delayed healing or nonunion (Schmitz, 1999). The use of nonsteroidal anti-inflammatory medications may inhibit bone healing, as can the nutritional status of the patient and compliance with the postoperative regime. Finally, prompt and appropriate treatment is needed because iatrogenic injury to the soft tissue envelope (ie, excessive periosteal stripping), distraction across the fracture site, inadequate immobilization or fixation, and the splinting effect of an intact fibula may contribute to the development of a nonunion. Historically, the definition of delayed union and nonunion have been based on time from the onset of injury. More recently, the exact time frames are considered to be less important. Fracture healing is a dynamic progressive process, and intervention is warranted by 3-5 months following injury if monthly radiographic studies do not show progression of fracture healing (Wiss, 1996). Typically, delayed union is a term used for a fracture that has not united within a period of time that would be considered adequate for bone healing. Delayed union suggests that union is slow but will eventually occur without additional surgical or nonsurgical intervention. The time frame is different for different fractures. Tibial diaphyseal fractures that do not show enough bridging callus to achieve clinical stability by 16 weeks are considered to have delayed union (Wiss, 1996). Nonunion refers to a fracture that will not unite without additional surgical or nonsurgical intervention (usually by 6-9 mo). PathophysiologyThe Weber-Cech classification is the most widely used (Weber, 1976). Fractures are classified according to radiographic appearance, which correlates with the fracture biology, as follows:
Determining if evidence of infection is present at the nonunion site is critical. Paley and Herzenberg classify nonunions according to clinical mobility as (1) stiff ( <5 degrees mobility), (2) partially mobile (5-20 degrees mobility), or (3) flail (>20 degrees mobility). These categories roughly correlate to the 3 Weber-Cech categories. Congenital pseudoarthrosis of the tibia is a unique condition observed in children. Neurofibromatosis and fibrous dysplasia are predisposing factors, although some are idiopathic in nature. The pathology seems to lie in the periosteum. INDICATIONSSection 3 of 12
Treatment principles and rationale The treatment of a tibial nonunion depends of the fracture classification, location of the nonunion, lower extremity alignment, fracture stability, presence of infection, soft tissue injury (including nerve deficits), and patient characteristics and possible concomitant injuries. A forthright discussion with the patient should be initiated, with the patient's wishes and the physician's experience should be taken into account. In general, hypertrophic nonunions are treated with rigid stabilization with or without compression. Additional biologic stimulation in the form of bone grafting is not required. Atrophic nonunions require augmentation to stimulate bone formation. This may require bone grafting, soft tissue coverage, or other forms of biologic stimulation, such as bone morphogenic proteins (BMPs). Infected nonunions should be treated in an attempt to sterilize the nonunion site, but stability of the fracture site should not be sacrificed. A treatment algorithm for tibial nonunions can be seen in Image 1. RELEVANT ANATOMYSection 4 of 12
See Pathophysiology. CONTRAINDICATIONSSection 5 of 12
Contraindications for operative management depend on a number of factors, all of which must be carefully weighed in the decision-making process. The overall health of the patient is critical to the decision-making process. If the patient is critically ill or has undergone multiple previous procedures without success, further treatment may not be possible or may be ill advised. Active infection modifies how and even whether or not the nonunion is treated. An injury to the neurovascular structures such that the foot is insensate may discourage heroic attempts for treatment of the nonunion. Amputation usually results in a quick return to activities, but it may result in overgrowth at the amputation site in children. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
Histologic FindingsA histologic assessment may be helpful and has been shown to have a high sensitivity (87%) and specificity (100%) when assessing nonunion for the possibly of infection, especially when microbiology findings are inconclusive (Simpson, 2002). TREATMENTSection 7 of 12
Medical therapyNonoperative methods Nonoperative methods should always be considered and, although rarely used as the definitive treatment, may be helpful as an adjunct treatment or as a temporizing option.
Surgical therapyTreatment principles and rationale Hypertrophic nonunions show prolific callus formation. These vascular nonunions have excellent healing potential. They are best treated with rigid stabilization with or without compression. Additional biologic stimulation in the form of bone grafting is not required. Atrophic nonunions are characterized by an absence of callus, deficient bone vascularity, and poor healing potential. Debridement of all necrotic tissue is necessary, with opposition of viable and vascular bone fragments. In addition, biologic stimulation is required. Historically, this has taken the form of bone grafting, preferably autograft, which is osteogenic, osteoconductive, and osteoinductive. The posterolateral approach is usually preferred to the anterolateral approach because greater space is available for bone grafting and an additional incision through the previous scar is avoided. The posterolateral approach should not be used in proximal third tibial fractures because of the high risk of injury to the neurovascular structures. Bone marrow injection has been shown to be an easy and effective treatment. This should be accomplished with the aid of fluoroscopy. Marrow is harvested from the iliac crest and injected directly into the posterior fracture site. In one study, 9 of 11 nonunions healed within 4-23 weeks, without further surgery (Sim, 1993). The use of BMP and other osteoinductive agents has gained increased support experimentally and clinically (Vaccaro, 2002; Heckman, 1991). With high costs and limited clinical applications, indications are still being developed. Surgical treatment Principles of surgical treatment include the incorporation of the following:
A fibular osteotomy should be used if the fibula is felt to be inhibiting compression across the tibial nonunion site. This is usually performed in combination with other procedures and is used as an isolated procedure only if a stable noninfected hypertrophic nonunion with little or no deformity is present. Usually a small segment of bone is removed (1-2 cm). Removal of necrotic or infected bone must be performed for a union to occur. This may involve the need for significant bone graft, shortening, or bone transport. Bony alignment and stability is essential for satisfactory treatment of a tibial nonunion. The use of a reamed intramedullary (IM) nail is an excellent method of treatment of noninfected nonunions, especially in the middle three fifths of the tibia (Wu, 1999). Conversion from a nonreamed nail or plate in closed and grade I or II open fractures with no evidence of infection is the primary indication. This technique has the advantage of early rehabilitation and maintenance of the alignment, and the reaming may act as a bone graft at the fracture site. For patients with a history of infection, previous external fixation, very proximal or distal fractures, or significant malalignment, this technique is less effective. This technique can also be difficult, and the surgeon must be experienced with IM nailing techniques. The use of end reaming (cutting) bits, fluoroscopy, and a femoral IM distracter may be helpful. Compression plating has also been shown to be effective for treating tibial nonunions. Wiss treated 49 patients with a tibial nonunion after initial external fixation (Wiss, 1992). The patients demonstrated a 92% healing rate in a mean of 7 months with no further treatment. Compression plating has the advantage of being applied anywhere along the tibia, and casting is usually unnecessary. However, it may contribute to difficulties with wound healing and can potentially devascularize a segment of bone. Handle the soft tissues in an atraumatic manner. Keep dissection and periosteal stripping to a minimum. Additionally, in patients with poor bone quality, the fixation is less secure. Recently, the use of a locking custom blade plate for periarticular nonunions has been described (Harvey, 2003). The use of external fixation, especially small wire and hybrid external fixation, is an excellent option for the treatment of tibial nonunions, especially if the fracture is very proximal or distal (periarticular), if significant bone loss occurred, if deformity (including shortening) is significant, or if ongoing infection is present. The use of external fixation allows for the treatment of multiple issues concurrently. External fixation can provide for stability of the fracture site, even in very proximal or distal fractures, with the use of fine wire fixation. Large infected bone segments can be removed and grafted, or a shortening can be performed. Limb length equalization can be performed with bone transport or as an isolated procedure after union has occurred. Adjunct therapy, such as the use of antibiotic bone cement or bone substitute beads, can easily be incorporated, and stabilization with external fixation usually provides for access if soft tissue grafts are needed. The use of external fixation is probably the best technique for patients with complex and significant angular deformities that require correction and are too great for acute correction. Although highly versatile, pin site infections occur routinely, making subsequent conversion to an IM nail difficult. Specialized training or experience in these techniques is important. COMPLICATIONSSection 8 of 12
Most complications that occur in the treatment of nonunions are an extension of the existing condition, but approach all tibial nonunions with great care to avoid making a bad situation worse. Possibly the greatest concern is creating an infected nonunion from an aseptic nonunion. In a 1994 study by Wu, a 13% rate of infection occurred, regardless of treatment technique (ie, compression plating vs IM nailing). The conversion from external fixation to IM nailing should be avoided if possible (Tornqvist, 1990). Malalignment, shortening, and continued nonunion may also occur, as well as graft site morbidity (if autograft is used). Other complications, such as neurovascular injury, compartment syndrome, persistent nonunion, and ultimately, amputation, may also result. OUTCOME AND PROGNOSISSection 9 of 12
Little documentation exists in the literature regarding the functional outcomes of patients treated for tibial nonunions. Discussing the potential limitations in future functional abilities with the patient is critical. Fracture healing does not mean full function, and residual weakness, pain, and limitations in function are common, even in appropriately treated patients with clinically successful outcomes. FUTURE AND CONTROVERSIESSection 10 of 12
The use of adjunct treatment modalities continues to be the most controversial topic, including the need and indication for electrical stimulation, ultrasonography, various synthetic bone osteoconductive carriers, and osteoinductive bone growth factors (such as BMP). MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
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