Abstract
Background
Complex nonunions of the lower limb long bones represent a challenging issue in orthopedics. Although the Ilizarov method is considered a successful treatment modality, its success varies with complications and patient-related factors.
Objective
This study aimed to evaluate the radiological and functional outcomes of the Ilizarov method in the management of complex nonunions of long bones. Specifically, we assessed bone healing, functional restoration, complication rates, and effectiveness of staged management strategies, including infection control and limb reconstruction.
Methods
This retrospective/prospective case series included 30 patients (31 nonunion cases) treated at three tertiary centers in Erbil city between 2020 and 2024. The patients underwent Ilizarov frame application following debridement and staged management for infection and bone transport. Outcomes were assessed using the Association for the Study and Application of the Method of Ilizarov criteria.
Results
The union rate of the study cohort was 90.3%, with a mean treatment duration of 9.26 months. Functional outcomes were rated as excellent, good, and poor in 67.7%, 22.6%, and 6.5% of the cases, respectively. Common problems included pin tract infections (35.5%), limb length discrepancy (32.3%), and malalignment (9.7%).
Conclusion
Although the Ilizarov method yielded high union rates and satisfactory functional outcomes in complex nonunions, limb length discrepancies and pin tract infections remain critical issues. Optimizing rehabilitation, compliance, and surgical planning is crucial for improving long-term functional outcomes.
Keywords
Introduction
Long bone nonunion is a crucial and complex orthopedic issue with considerable functional, psychological, and financial consequences.1,2 Up to 2% of fractures have been reported to result in nonunions. In cases of high-energy trauma and open fractures, the risk of nonunion can reach up to 20%.1,2 Nonunion is accompanied with pain, disability, and reduced quality of life, with most cases requiring long-term surgical and rehabilitative care. 3 The pathophysiology of nonunion involves patient-dependent and injury-specific factors, including smoking, diabetes, soft tissue damage, and infection. These risk factors create a hostile biological environment that compromises bone healing. 4 When compounded by severe complications, such as bone loss, deformities, and infection, these injuries are classified as complex nonunions, which are particularly challenging to manage.4,5 Gavriil Ilizarov developed the Ilizarov method in the 1950s, which is considered the gold standard for treating complex nonunions, with a specific use in cases involving bone defects and infection. It employs the laws of distraction osteogenesis for bone regeneration, with infection eradication and deformity correction in a concurrent manner. One of the crucial biomechanical laws is the “law of tension stress,” which induces regeneration of the vasculature, soft tissue, and bone through mechanically regulated tension.3,5 Although the Ilizarov method is highly effective, it is associated with a demanding treatment course, including prolonged external fixation, burden of pin tract infections, and the need for meticulous postoperative care. 4 Despite these challenges, the method provides unparalleled success rates in achieving union, eradicating infection, and restoring limb function, often serving as a limb salvage option in cases where amputation might otherwise be considered.3,4 Although numerous studies have confirmed the efficacy of the Ilizarov method in healing complex nonunions, variation in documented success rates indicates a necessity for sound clinical information, most particularly in developing nations with limited access to medical technology and care. To evaluate functional and radiological success of the Ilizarov method in complex nonunions of long bones of the lower limb, the union, healing period, and complications have been taken into consideration in this study.
Methodology
This study was conducted following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines to ensure transparency, accuracy, and reproducibility in reporting observational clinical outcomes. 6 This case series employed a mixed retrospective/prospective design, with initial data collected from medical records and subsequent data from prospective follow-up for outcome assessment. This case series analyzes the outcomes of the Ilizarov method in treating complex nonunions of the lower limb long bones. The study was conducted at three different tertiary centers in Erbil city between 2020 and 2024; however, all surgical procedures were performed by the same surgical team to ensure consistency in the operative techniques and postoperative management. Ethical approval was obtained from the institutional Research Ethics Committee of the Hawler Medical University (Approval Code: 3-7, Date: 11-1-2022). The study was conducted in accordance with the Helsinki Declaration.
Patient selection and inclusion criteria
A total of 30 patients with 31 complex nonunions were enrolled in the study. Complex nonunion was defined as cases involving several failed operations, loss of bone segments, loss of soft tissue, resistant infection, significant limb shortening, deformity, or joint stiffness with osteopenia. Patients with active or quiescent infection at the nonunion or an adjacent site and those without infection were included in this study. Patients with severe systemic comorbidities for whom surgical intervention could not be conducted and those with an insistent lack of willingness for Ilizarov therapy were excluded from this study. Two cases were excluded from the analysis due to incomplete follow-up data. History, clinical examination, and radiography (X-rays, with additional use of computed tomography when required) were conducted preoperatively. The presence of infection was examined in terms of symptoms, laboratory tests (erythrocyte sedimentation rate, C-reactive protein, and white blood cell count), and microbiological cultures.
Surgical procedure
All patients underwent surgery by a single experienced orthopedic surgical team using the Ilizarov method. The surgical technique consisted of several key stages. All procedures began with open debridement of the necrotic bone and infected tissue, ensuring that only healthy, bleeding bone remained at the site. The medullary canal was reamed proximally and distally, and bone samples were obtained for microbiological and histopathological analyses to assess the infection status.
For septic nonunion cases, infection management was prioritized. In cases of active infection (e.g. chronic osteomyelitis with discharging sinus, persistent soft tissue infection), the Ilizarov frame was applied, and corticotomy and bone transport were delayed until infection control was achieved through staged debridement and use of targeted antibiotics.
The choice of bone transport strategy was determined by the size of the bone defect after debridement. In cases where the bone gap was <4 cm, an acute docking procedure with compression was performed, whereas defects exceeding 4 cm required gradual bone transport using the Ilizarov external fixator.
When required, corticotomy was performed proximal or distal to the nonunion site to facilitate distraction osteogenesis and new bone formation. For patients with infection, corticotomy was postponed until the infection was under control. Stabilization and compression of the bone segments were achieved with a multi-ring Ilizarov frame, ensuring appropriate docking and secure fixation.
Postoperative management
Following surgery, all patients received a structured postoperative care protocol to enhance healing and reduce complications. For patients with infected nonunions, intravenous antibiotics were administered for 3 weeks based on culture and sensitivity results, followed by 3 additional weeks of oral antibiotics. The antibiotic regimen was tailored to each patient based on their microbiological findings. All patients were encouraged to begin weight-bearing immediately postoperatively with the assistance of an aid, depending on pain tolerance and stability. Formal physiotherapy services were not available, but patients and their families received education on home-based exercises and frame care.
Distraction osteogenesis protocol
For patients undergoing gradual bone transport, distraction was initiated 6–10 days postoperatively, progressing at a rate of 1 mm/day based on the standardized protocol followed by the surgical team.
Follow-up and radiographic evaluation
The patients were examined 1 week after surgery, during which healing and care of the pin site were assessed. Subsequently, follow-up was performed at weekly intervals during the period of distraction. The first radiograph examination was performed 3 weeks postoperatively (2 weeks post-distraction) and then at monthly intervals. After radiographic healing of the bone (i.e. at least three cortices bridging in two views), all connecting rods were removed and patients were instructed to start full weight-bearing walking. If the patient was able to mobilize comfortably without pain and no abnormal movement was observed in the nonunion site upon tension, the Ilizarov frame was removed and a patellar tendon–bearing cast was applied in tibial cases.
Outcome assessment
The success of the procedure was evaluated using radiographic and functional criteria. Healing was defined as the presence of radiological union with three cortices bridging in two views. Clinical function was assessed using the Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria, which assesses results based on bone healing, limb function, and patient mobility. The ASAMI scoring system categorizes outcomes as excellent, good, fair, or poor based on bone union, deformity, infection status, and the ability to bear weight without assistance. 7 Problems, obstacles, and complications encountered during treatment were meticulously documented. In select cases, limb shortening was intentionally accepted to reduce the duration of external fixation, particularly in cases of large bone defects, wherein length restoration would have significantly prolonged treatment. The decision was based on patient-specific factors, including bone defect size, infection control, and functional demand, ensuring that the final limb discrepancy remained within a range manageable with orthotic compensation or minor corrective procedures.
As the majority of cases had active or transient infections, infection eradication was the primary treatment goal. Patients were monitored during follow-up to ensure infection resolution before assessing functional and bone healing outcomes.
Nonunion classification was performed using Paley’s criteria, which categorizes nonunions based on bone loss, stability, and deformity and guides treatment strategy. 8
Statistical analysis
All statistical analyses were performed using Jamovi software version 2.3 (The Jamovi Project, Sydney, NSW, Australia). 9 Descriptive statistics were used to summarize continuous variables, such as patient age, time to union, and bone transport length, which were expressed as mean and standard deviation or median and interquartile range as appropriate. Categorical variables, including infection status and ASAMI bone scores, were presented as frequencies and percentages. Comparisons between uninfected and infected nonunions and between acute docking and bone transport groups were conducted using an independent samples t-test for continuous normally distributed values and the Mann–Whitney U test for nonnormally distributed values. Categorical variables were compared using a chi-squared test, with the Fisher’s exact test used when required. In a secondary analysis, a multiple model was created for predicting prolonged healing duration, and variables such as age, infection, bone defect, and number of previous surgeries were included in the model. p-values of <0.05 were considered to indicate statistical significance.
Results
A total of 31 nonunion cases from 30 patients were included, with a mean age of 31.2 (standard deviation (SD): 15.7, range: 6–67) years and a median age of 26 years (Figures 1 and 2).
Sequential management of an infected tibial nonunion using the Ilizarov method. (a) Preoperative radiographs of a 63-year-old man with left-sided hemiplegia showing a complex tibial nonunion with segmental bone loss following intramedullary nailing. (b) Clinical photograph depicting a chronic infected nonunion with an open wound, purulent discharge, and exposed necrotic bone prior to surgical intervention. (c) Early postoperative radiograph demonstrating Ilizarov external fixation after debridement and acute compression at the nonunion site. The frame configuration was designed for stability and gradual deformity correction. (d, e) Intraoperative images showing the application of a multi-ring Ilizarov fixator following extensive debridement and preparation for distraction osteogenesis and (f) Radiographs obtained 3 months after Ilizarov frame removal, confirming complete bone union with cortical bridging at the previously nonunited site.
Staged Ilizarov management of distal tibial nonunion with implant failure. (a) Preoperative radiographs of a patient with distal tibial nonunion and broken hardware after three failed surgical attempts, including autogenous iliac bone grafting. The image shows a failed plate and screws with persistent nonunion and bone resorption, taken 15 months after the initial injury. (b) Immediate postoperative anteroposterior (AP) and lateral (LAT) radiographs following debridement of the nonunion site and proximal tibial corticotomy. An Ilizarov circular external fixator was applied for stabilization, bone transport, and progressive deformity correction. (c) Radiographs taken 7 months postoperatively, immediately prior to frame removal. The images show regenerate bone formation at the proximal tibial corticotomy site and consolidation at the docking site and (d) Radiographs of the leg (AP and LAT) 3 months after frame removal.
The mean limb length discrepancy (LLD) was 2.10 (SD: 1.83) cm, and the average bone gap size was 3.61 (SD: 3.31) cm. The mean bone deficiency, which is the sum of bone gap size and LLD, was 5.65 (SD: 3.43) cm. Most patients were male (87.1%, n = 27). Nonunion was most commonly observed in the tibia (71.0%), followed by the femur (25.8%) and ankle (3.2%). Among these cases, 11 (33.48%) had active infection with discharge, 13 (41.9%) had quiescent infection without discharge at the time of surgery, and 7 (22.62%) had no history of infection. Traffic accidents (54.8%) were the leading cause of nonunion, followed by blast injuries (16.1%) and falls (12.9%). Smoking was the most common comorbid condition, observed in 36.8% (n = 7) of the cases, followed by compromised soft tissue envelopes (26.3%, n = 5) and diabetes mellitus (15.8%, n = 3). Less frequent comorbidities included obesity, alcoholism, and vascular repair history. The most common treatment goal was to restore limb length and alignment while achieving union (35.5%, n = 11). Other goals included eradicating infections and achieving alignment restoration (16.1%, n = 5) or accepting limited limb shortening to achieve union (6.5%, n = 2) (Tables 1 and 2).
Patient demographics and initial characteristics.
LLD: limb length discrepancy; SD: standard deviation.
Distribution of patient sex, nonunion location, infection status, and etiological factors.
LLD: limb length discrepancy.
Based on Paley’s classification, the most common type of nonunion observed was Type B3, characterized by pseudarthrosis with >1 cm of bone loss, bony defect, and shortening, accounting for 35.5% (n = 11) of the cases. Type B1, defined as pseudarthrosis with >1 cm of bone loss and bony defect without shortening, represented 25.8% (n = 8) of the cases. Other types of nonunion included Type B1 (16.1%, n = 5) and Type A1 (9.7%, n = 3). Overall, the success rate was high, with 90.3% (n = 28) of the cases achieving their predefined treatment goals. The detailed classification of nonunion types is presented in Table 3.
Classification of nonunion based on Paley’s criteria.
Treatment and outcomes
The average time from initial treatment to Ilizarov frame application was 12.7 months. Active infections occurred in 35.5% of the cases, with Staphylococcus aureus being the most common pathogen (Tables 4 and 5). The mean frame application duration was 8.32 months, with the total treatment time averaging 9.26 months. Problems included pin tract infections (35.5%), malalignment (9.7%), and axial deviation (9.7%). External fixation index (which is equal to lengthening (in cm) divided by the number of months spent in external fixation) was applicable for only 19 cases in our case series; in the remaining cases, no corticotomy was performed for lengthening. The mean external fixation index was 0.66. At the time of frame removal, 64.7% of the cases had no LLD. In the remaining cases, LLD was intentionally planned and agreed upon with the patient from the beginning to balance treatment efficiency and avoid the prolonged use of an external fixator. This planned discrepancy was based on factors such as patient adaptation, bone healing potential, and the need to reduce complications associated with extended fixation time.
Treatment characteristics and outcomes.
LLD: limb length discrepancy; ASAMI: Association for the Study and Application of the Method of Ilizarov; IMN: intramedullary nailing.
Categorization of problems, obstacles, and complications in nonunion management.
LLD: limb length discrepancy.
The ASAMI scoring system revealed that functional outcomes were excellent, good, fair, and poor in 67.7%, 22.6%, 3.2%, and 6.5% of the cases, respectively. Furthermore, bony outcomes were excellent, good, fair, and poor in 51.6%, 35.5%, 3.2%, and 9.7% of the cases, respectively.
Functional outcomes and associated factors
Functional outcomes varied significantly across different factors (Table 6). Nonunion in the tibia was associated with the highest percentage of excellent outcomes (58.06). LLD alone demonstrated no significant impact on the outcomes (p = 0.467). However, patients with delayed union and LLD > 4 cm were associated with poorer functional outcomes. Among the mechanisms of injury, traffic accidents were frequently associated with excellent outcomes (41.93, p = 0.020). A higher number of previous surgeries (≥5) was strongly associated with poorer outcomes (p < 0.001). Infection status and duration of frame application showed no significant correlations with functional outcomes (p > 0.05). Smoking and compromised soft tissue envelopes were notable comorbid factors; however, these factors had no statistically significant impact on the functional outcomes (χ2 = 33.6, p = 0.584). Other complications, including regenerating fractures and recurrent infections, demonstrated weaker associations with functional outcomes.
Correlation analysis of functional outcomes based on nonunion location and other clinical variables.
LLD: limb length discrepancy; ASAMI: Association for the Study and Application of the Method of Ilizarov.
Analysis of predictors for total regenerate length
Linear regression analysis identified significant predictors of total regenerate length (Table 7). The nature of the infection (active with sinus vs. compromised soft tissue envelope: β = −4.000, p = 0.028) and LLD (LLD > 4 cm vs. no LLD: β = −4.486, p = 0.086) were associated with reduced regenerate length. The mechanism of injury and site of nonunion showed no statistically significant impact on the outcomes (p > 0.05). Based on one-way analysis of variance, no statistically significant difference was observed in the total regenerate length between sexes (F = 0.648, df1 = 1, df2 = 3.70, p = 0.469). However, descriptively, the mean total regenerate length was higher in females (mean = 5.25 cm, SD =3.77 cm) than in males (mean = 3.65 cm, SD = 3.28 cm).
Linear regression analysis of predictors of total regenerate length.
LLD: limb length discrepancy.
Discussion
This study validated the effectiveness of the Ilizarov method in healing complex long bone nonunions, particularly in cases of infection, bone defects, and LLD, with a union success rate of 90.3% and satisfactory functional success observed in 67.7% of the cases. The current study validates the findings of the study by Bakhsh et al., 10 in which a union was achieved in 98% complex femoral nonunions using the Ilizarov method. They reported the efficacy of the Ilizarov method in healing bone and eradicating infection in 94% of cases. However, complications in the form of pin tract infections (80%) and stiffness of the knee (60%) in cases similar to those in our study were encountered. The union rate observed in the current study (90.3%) was consistent with those reported by Tilkeridis et al., 11 who demonstrated the efficacy of the Ilizarov method in achieving union in complex tibial fractures and nonunions, even in mass casualty settings. Their study highlighted that all but one fractures healed, with successful limb length restoration observed in three of the four patients undergoing corticotomy. The favorable outcomes are likely attributable to the technique’s unique ability to promote distraction osteogenesis while addressing infection and deformity.
Although the majority of cases achieved excellent or good ASAMI outcomes, some patients did not reach an exceptional result due to persistent complications. Bone healing outcomes were affected by factors such as delayed union, incomplete regenerate consolidation, or residual limb shortening. Functional outcomes were influenced by persistent joint stiffness, muscle weakness, and gait abnormalities, requiring prolonged rehabilitation. Additionally, in a subset of cases, recurrent infections contributed to poorer scores, necessitating further surgical interventions or extended antibiotic therapy. These findings highlight the importance of early rehabilitation, infection control, and limb alignment optimization for improving long-term functional outcomes.
Kumar et al. 12 revealed a mean union period of 7 months, with 47.6% and 38.1% of patients having excellent and good function, respectively, as per the ASAMI criteria; however, several complications, including 40.9% pin tract infection and 9.5% refracture, warranted meticulous postoperative care and follow-up for a long duration. The study by Akhtar et al. 13 involving 45 patients with post-traumatic aseptic tibial nonunion treated with the Ilizarov fixator reported a 91.1% bone union rate; however, the functional outcomes varied significantly. Using the Karlstrom–Olerud scoring system, no cases with excellent outcomes were observed, while 13.33% were classified as poor, 28.89% as moderate, and 22.2% as satisfactory. The most common complications included pin tract infections and joint stiffness, underscoring the challenges in achieving optimal functional recovery despite successful bone union. The authors attributed poorer outcomes to patient compliance issues and their early learning curve. Malalignment and LLD were reported in 9.7% and 23.3% of the cases, respectively. Despite planned shortening, to shorten the duration of external fixation, meticulous intraoperative planning and follow-up were warranted in a small number of cases. The findings of this study aligned with those of a systematic review by Yin et al., 14 which reported a high rate of complications associated with the Ilizarov method in infected tibial and femoral nonunions. Their meta-analysis of 590 patients revealed a 56% incidence of pin tract infections, and knee stiffness (12%), malunion (7%), and refracture (4%) were also notable postoperative challenges. Additionally, 13% of cases developed peroneal nerve palsy, highlighting the need for careful perioperative nerve protection. These results underscore the need for meticulous frame management and long-term rehabilitation to mitigate complications and optimize functional outcomes. The analysis revealed various predictors of reduced satisfactory function, such as increased surgical burden and nonunion. Patients with ≥5 surgeries showed poor function, with a significant impact of surgical burden on the overall function. Similarly, LLD >4 cm predicted poor function restoration. Consistent with the finding of Meleppuram et al., 15 poor function was observed in patients with a high surgical burden, with 55% of these patients exhibiting excellent function at 100% union, compared with 100% union in single operations. Similarly, Pawik et al. 16 found that compared with a healthy control group, patients treated with the Ilizarov method for tibial nonunion exhibited persistent gait abnormalities, including reduced step length, slower walking velocity, and asymmetrical weight distribution. These findings suggest that although the Ilizarov method successfully addresses bone healing, functional limitations may persist, particularly in cases involving extensive prior interventions or significant LLDs. The Ilizarov method’s ability to simultaneously address infection, deformity, and bone defects in a single-stage procedure distinguishes it from other techniques, such as the Masquelet method, which requires a two-stage approach. The study by Zhang et al. 17 compared the Ilizarov bone transport technique (IBTT) with the Masquelet combined with free-flap technique in treating severe tibial and soft tissue defects. Although both methods achieved bone union, IBTT had a significantly longer bone union time (11 vs. 6 months, p = 0.001) and a higher overall complication rate (40% vs. 22.9%). Additionally, joint stiffness and docking site nonunion were more frequent in IBTT cases, suggesting that the method requires longer treatment duration and greater patient compliance despite being effective for large bone defects.
Our study confirms the use of the Ilizarov method as a sound alternative for complex nonunions, specifically in settings with limited resources and in cases where limb salvage is a major issue. Study limitations include the relatively small cohort and observational data, which could contribute to selection bias. Long-term studies with larger groups and comparative analysis could yield a complete picture of best practice in optimizing outcomes and minimizing complications in such patients.
Conclusion
This study demonstrated a high union success rate and excellent or good functional outcomes in the majority of cases, supporting the utility of the Ilizarov method as a reliable limb salvage option. However, complications such as pin tract infections, LLDs, and joint stiffness remain significant challenges. A high number of surgeries and high number of LLDs may be associated with a poor prognosis, warranting early intervention, careful surgical planning, and successful postoperative care. In its arduous therapeutic journey, the Ilizarov method remains a part of complex nonunion therapy, particularly in environments with limited resources and in cases where limb salvation is a major issue. Further comparative studies with a larger sample size are warranted to maximize therapeutic protocols and minimize complications.
Footnotes
Acknowledgements
None.
Author contributions
Ahmed Ibrahim Berzenji conceived the study, performed surgeries, and collected clinical data.
Dedawan Namiq Rasul contributed to study design, data analysis, and manuscript drafting.
Abdulkadr Muhammed S Alany supervised the project, revised the manuscript critically for intellectual content, and ensured adherence to ethical standards. All authors have read and approved the final version of the manuscript.
Data availability statement
The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.
Declaration of conflicting interests
The authors declare that there is no conflict of interest.
Ethical considerations and informed consent
This study was conducted in compliance with the Helsinki Declaration of 1975, as revised in 2024, and was approved by the Hawler Medical University, College of Medicine, Research Ethics Committee (Meeting Code: 3, Paper Code: 2, Date: 4-1-2022). A copy of the IRB approval document has been submitted as supplementary material.
As this study included both retrospective and prospective phases, informed consent was obtained for both phases. To ensure patient confidentiality, all identifying information was fully de-identified prior to data analysis. No personal identifiers, including names, birth dates, or hospital identification numbers, were included in the study data.
This study adhered to the STROBE guidelines for the reporting of observational studies, and all relevant EQUATOR Network recommendations were followed.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
