In the history of external bone fixation, complications have not only meant delayed treatment time, increased patient pain, threatened limb function, and even had life threatening effects. In the early stage, the complications of external fixation have been troubling the clinicians, and they were even prohibited because of the seriousness of the complications, which caused extensive controversy. With the popularization of the technique in the 1980s, the complications of external bone fixation were fundamentally solved, life-threatening and limb-functioning complications no longer occurred, and the rate of pinhole infection was reduced to less than 1%. Like other techniques, one or more complications can occur, but the severity is not as serious and “scary” as one might think. With the improvement of external fixators and technical refinement, the complications of today’s external fixation have not only decreased dramatically, but the serious complications have also decreased dramatically. For example, Parkhill, Paley, Zhao Yi d, etc. believe that the complications of modern bone fixation are not related to technology. Complications are much lower and less severe than those of other orthopaedic procedures and are easily managed if they do occur. Almost all complications of external bone fixation can be cured.
The types, incidence and severity of complications of external bone fixation often vary greatly from scholar to scholar and can vary greatly depending on the type and number of conditions treated, the type of external fixator used, the level of skill and clinical experience of the reporter. It is difficult to reach a consensus on a uniform definition of complications and assessment criteria. There is a lack of statistical basis for the complications of overall external bone fixation.
Overview of complications of external bone fixation
Due to the structural defects of early external bone fixators, the poor stability of fixation and the outdated materials used, complications are not only high but also serious, such as seizure-like convulsions, skin necrosis, sepsis, osteomyelitis, severe shock, and death are frequent. Common clinical complications are as follows.
I. Problems of steel needles
1, fixed steel pin loosening pin loosening is a common problem in bone external fixation treatment, affecting the stability of the bone external fixation system, resulting in poor bone healing or secondary infection.
2, pin tract infection tract infection is the most common complication after the application of bone external fixator, ranked first in many complications. The incidence varies widely among groups, ranging from 1% to 80%, which is related to the type of disease applied, the type of external fixator selected, the technique used and the experience. the Ilizarov institute summarized the incidence of pin tract infection complication in 3669 cases of applying circumferential limb external fixator as 8,3%. lewallen and Edwards reported that the complication of femoral and cavernous pin tract infection accounted for about 10%, which affecting 1/3 of the patients. The incidence of femoral and pelvic nail tract infections was approximately 16%, affecting 40% of patients. The incidence of hand and foot infections was lower, at approximately 1%. These data suggest that the incidence of nail tract infections is related to the soft tissue coverage conditions at the location of the nail.
(1) Aseptic inflammatory reaction of the needle tract Most “needle tract infections” are of this type, i.e., swelling of the needle tract opening with exudate and negative bacterial cultures, often not involving deep soft tissue and bone tissue, and not affecting the entire treatment process.
(2) needle tract infection needle tract mouth inflammatory response to the skin and soft tissue defense function is weakened, if improper hygiene care around the needle, cell contamination retrograde infection, growth and reproduction in the needle tract, then cause a real needle tract infection. Further progression to deeper areas results in osteomyelitis, joint or even systemic infection.
Paley classifies needle tract infections into 3 grades, grade I, soft tissue inflammation; grade II, soft tissue infection; and grade III, bone infection. According to CheckettsandOttenburn’s typing, nail tract infections are classified as follows: grade 1, localized oozing and redness of the skin around the nail tract, requiring local care; grade 2, redness of the skin around the nail tract, soft tissue tenderness, and sometimes leakage of fluid, requiring local care and oral antibiotics; grade 3, symptoms similar to grade 2, but failing to improve with careful care and oral antibiotics. Grade 4, serious soft tissue infection, through careful care and oral antibiotics failed to improve the nail tract greater than 1, then to remove the fixed nail, give up the external fixation bracket; Grade 5, the soft tissue situation as grade 4, but involving bone tissue, X-ray shows osteomyelitis, should remove the external fixation bracket; Grade 6, bone and soft tissue to form a sinus tract, need greater surgery to treat.
3, steel needle fatigue fracture is caused by metal fatigue, the most likely site is the joint of needle and connecting rod.
4, steel needle peri-skin compression necrosis limb swelling, tension between the steel needle and the skin, when the connecting rod is too close to the skin, the skin pressure as well as the placement of the limb by its own gravity, producing peri-needle skin compression necrosis.
Second, the complications of bone
1, delayed healing of fracture and bone discontinuity is another major complication of external fixator treatment of fracture, the incidence is high, Dwyer reported 20%-30%, Emerson reported up to 80%.
2, fracture angular deformity or re-displacement when treating fractures, especially femoral stem fractures, are prone to angularity or re-displacement due to the developed thigh muscles and the high strength requirements of fixation. During bone lengthening, the imbalance of muscle force in different parts of the bone marrow causes axial deviation of the bone, which also leads to deformed healing of the fracture.
3, pin tract fracture and re-fracture fracture are mostly seen in patients with bone lengthening, Eldridge reported the incidence of re-fracture in bone demented lengthening is 3%. For cases where the re-fracture occurs at the site of pin insertion, it is related to the use of steel pins that are not proportional to the diameter of the bone. When the bone strength is poorer than normal cortex after fracture healing, it is easy to cause re-fracture once the external fixator is removed.
4, early healing early healing occurs when the bone lengthening is related to incomplete osteotomy or failure of traction technique.
Joint complications
1, joint contracture to be seen in patients with limb lengthening, the incidence of 1% to 7%, Eidridge reported single-plane external fixation bracket bone demented lengthening joint contracture incidence of 3%, while the annular bracket bone lengthening for 1%.
2, joint movement is limited after using bone external fixator, adjacent joint movement is limited, is also one of the complications of application. In particular, after the application of bone external fixator treatment for femoral stem fracture, it often produces limitation of knee flexion.
3. Joint dislocation occurs during bone lengthening, which may also lead to changes in articular cartilage and complications of osteoarthritis.
IV. Nerve and vascular complications
1, nerve injury whether during the installation of the bone external fixator surgery, or in the subsequent treatment process can occur in the peripheral nerve was damaged, resulting in sensory or motor impairment.
Lin has reported a case of single-plane half-pin external fixation stent for cavity row bone fracture causing injury to the anterior cavernous artery; Jakin layer reported a case of Ilizarov stent external fixation causing delayed injury to the femoral artery and forming pseudoaneurysm.
3, limb swelling bone lengthening process limb often swollen, to be alert to the deep vein thrombosis caused by the limb swelling.
4.Osteofascial compartment syndrome can be caused by the insertion of nails transversely through the osteofascial compartment, or the increase of intraosseous pressure within the osteofascial compartment after cortical cutting.
Complications have occurred with the development of this technique since its inception. The prevention and avoidance of complications and the reduction of their incidence are the hallmarks of the maturation of external fixation techniques. Although “complications” are often mentioned in clinical practice, their definition is still unclear. Due to the irregularity and ambiguity of complications, many problems that should not occur or can be avoided will occur, which will have a series of effects on the efficacy, physician’s perception and doctor-patient relationship, and become an obstacle to the advancement of external bone fixation technology.