A retrospective cross-sectional study was conducted at Cho Ray Hospital, Ho Chi Minh City, Vietnam. Medical records and radiographs of all patients who underwent surgical treatment for aseptic nonunion of the femoral shaft from January 2017 to December 2023 were reviewed.

Eligible patients were aged 16 years or older with a diagnosis of aseptic femoral shaft nonunion following previous osteosynthesis of a femoral shaft fracture.

Inclusion criteria were as follows:

Persistent nonunion for ≥6 months after initial fixation.

Radiological features of nonunion located between the subtrochanteric region and 4-6 cm proximal to the distal femoral condyles.

Absence of clinical or laboratory evidence of infection.

Patients were excluded if they had segmental bone loss >3 cm, systemic contraindications to surgery (e.g., severe cardiopulmonary disease, uncontrolled diabetes, chronic renal failure), neurological disorders affecting limb function, or inability to comply with follow-up.

Nonunion was defined as the absence of progressive healing for at least 6 months after initial fixation, accompanied by both clinical signs (persistent pain or instability) and radiographic evidence of non-healing [7,8]. This definition is consistent with widely accepted orthopedic criteria. Although the U.S. FDA defines nonunion at 9 months, earlier diagnosis at 6 months is commonly adopted in clinical practice when there is no evidence of progression toward union.

Aseptic nonunion was defined based on a combination of clinical, laboratory, and intraoperative findings. Patients were required to have no history suggestive of prior infection (e.g., no wound drainage, sinus formation, or previous surgical site infection), no clinical signs of infection, and normal inflammatory markers (WBC 4-12 × 10⁹/L, ESR < 22 mm/h, CRP < 0.7 mg/dL). In cases with any suspicion of infection, intraoperative tissue samples were obtained for microbiological culture under sterile conditions. In patients with late-presenting nonunion but no clinical or laboratory suspicion of infection, intraoperative cultures were not routinely performed and were left to the discretion of the operating surgeon.

Only cases with no clinical, laboratory, or microbiological evidence of infection were classified as aseptic nonunion and included in the study. In accordance with current concepts in nonunion management, treatment strategies should address both biological viability and mechanical stability [9].

All operations were performed by experienced orthopedic surgeons using a multimodal reconstructive approach designed to enhance both biological and mechanical factors of bone healing. Each patient received at least two of the three bioactive enhancement techniques described below (Figure 1).

The procedure consisted of the following steps:

Judet-style cortical decortication (JCD) creates pedicled osteoperiosteal bone flaps to stimulate local vascularity and enhance biological activity at the nonunion site.

Meticulous debridement of fibrous tissue and sclerotic bone ends, followed by grafting with morselized autologous cancellous bone (MACBG) harvested from the iliac crest, tightly packed into the nonunion gap.

Application of onlay cortical strut grafts (OCSG) across the nonunion site, secured with cortical screws to provide additional mechanical reinforcement and restore bone continuity (Figure 1).

Simultaneously, rigid internal fixation was applied, using either an intramedullary nail or a plate-and-screw construct. In selected cases, the existing fixation device was retained, exchanged, or converted to achieve optimal stability. When instability was suspected, a small anti-rotational plate (augmentation plate) was applied to enhance construct rigidity (Figure 1) further.

Radiographic examples of nonunion and postoperative construct are shown in Figure 2.

Demographic data (age, sex, affected side, fracture level), fracture characteristics, prior fixation type, and surgical details were extracted from hospital archives. Initial injury characteristics, including mechanism of injury and fracture classification (e.g., AO classification), were not consistently available due to the referral nature of the cohort. Therefore, they were not included in the analysis. Donor-site complications were systematically assessed based on clinical follow-up records at each postoperative visit, including pain at the iliac crest, infection, hematoma, and other local complications. Only clinically significant complications documented during follow-up were recorded.

Radiographic classification of nonunion followed Weber-Cech (1976) criteria (hypertrophic, oligotrophic, atrophic) [7].

Postoperative radiographic images were collected (Figure 2).

Clinical and radiographic evaluations were performed until bone union was achieved or treatment failed.

Union was defined as pain-free weight-bearing and bridging callus on ≥3 cortices in orthogonal radiographs.

Failure was defined as persistent nonunion or implant breakage after ≥7 months of follow-up.

Descriptive statistics were used to summarize patient characteristics, surgical techniques, and clinical outcomes. Continuous variables are presented as means with ranges, and categorical variables as frequencies and percentages. Due to the relatively small sample size and heterogeneity in treatment strategies, no formal statistical analysis was performed to compare treatment groups.

This retrospective study was approved by the Institutional Review Board of Cho Ray Hospital, Ho Chi Minh City, Vietnam (approval No. 25-25/GCN-HĐĐĐ, April 1, 2025) and was conducted in accordance with the Declaration of Helsinki. Due to the retrospective design and anonymization of patient data, the ethics committee waived the requirement for informed consent.

Between 2017 and 2023, a total of 4,129 patients with femoral shaft fractures were recorded at Cho Ray Hospital. Among these, 216 cases were identified as femoral shaft nonunion. Of these nonunion cases, 54 aseptic nonunion cases met the inclusion criteria. The mean age of the patients was 39.3 years (range: 16-72 years). Most patients were in the working-age group (21-40 years), accounting for 50% of the cohort. Demographic and clinical data are summarized in Table 1. All patients underwent autologous iliac crest bone grafting, including both cancellous bone grafts and cortical strut grafts.

According to the Weber-Cech classification, 48 cases (88.9%) were hypertrophic or oligotrophic, and 6 cases (11.1%) were atrophic. Intramedullary nailing was the most common initial fixation (63%), followed by plating (26%) and other techniques (11%) (Table 2).

The mean interval between the initial fixation and revision surgery was 11.3 months (range, 6-28 months). The mean follow-up period was 25.3 ± 13 months (range, 6-72 months).

The overall bone union rate was 96.3% (52/54). Union was achieved in all hypertrophic and oligotrophic cases (100%) and in four of six atrophic cases (83.3%).

Depending on the previous fixation, the multimodal revision technique involved Judet-style decortication, morselized cancellous bone grafting, and onlay cortical strut grafts. The overall union rates according to the revision method are shown in Table 3.

The detailed outcomes according to the type of previous fixation and the multimodal surgical technique are presented in Table 4, Table 5, and Table 6. Each table shows the distribution of cases according to the applied biological and mechanical enhancement procedures, including morselized cancellous bone graft, Judet-style decortication with pedicled bone flaps, and onlay cortical strut grafts (a cortical strut harvested from the iliac crest fixed across the nonunion gap with two screws).

In patients with retained or dynamically adjusted intramedullary nails, union was achieved in all seven cases. The combination of Judet decortication and onlay grafts demonstrated the most consistent union results in this group.

In the plate fixation group, the best outcomes were achieved with plate augmentation and exchange nailing, both yielding 100% union rate. One case of nonunion was observed in the plate replacement subgroup.

In cases previously treated with other fixation methods, such as Küntscher nails, DHS, and DC, the multimodal approach also achieved high union rates. Exchange nailing and plate augmentation were associated with excellent outcomes, with only one nonunion recorded in the retained subgroup.

Only two cases (3.7%) failed to achieve bone union. Mild, transient donor-site pain at the iliac crest occurred in 5.5% of cases. Postoperative shortening ≤2 cm was observed in the majority of patients and was considered clinically acceptable. Angular or rotational deformity >5° occurred in just one case. Knee flexion ≥120° was preserved in 72.2% of patients, and 96.3% had full extension.

In this series, both augmentative (supplementary) plating and exchange nailing produced excellent and identical healing—100% union in their respective groups—while plate replacement and retain/dynamization trailed modestly. This pattern is consistent with contemporary evidence. Systematic reviews and comparative studies reporting femoral shaft nonunion after failed intramedullary nailing increasingly favor augmentative plating over exchange nailing, with pooled or reported union rates typically in the mid-90s to near-100% for augmentative plating and a wider, often lower range (≈72-100%) for exchange nailing. Notably, a 2013 systematic review recommended plating after failed nailing and exchange nailing after failed plating; later meta-analyses and comparative series have shown that augmentative plating achieves faster healing and fewer complications than exchange nailing [10,11] while maintaining very high union rates [10,12]. Our 100% union rate in both groups likely reflects concurrent biological optimization (routine cancellous autografting, frequent decortication, and selective strut augmentation), which may elevate exchange nailing outcomes to the top of their historical range.

All patients in our cohort received autologous cancellous iliac crest bone graft (ICBG), and many also underwent Judet-style decortication and/or onlay cortical strut augmentation. The near-universal union mirrors the literature, in which ICBG remains the reference standard for long-bone nonunion (union commonly ≈ 90-97%). Decortication with plate fixation is repeatedly associated with union rates >90% in long-bone nonunion, including the femur. In oligotrophic/atrophic patterns or mechanically demanding reconstructions, onlay cortical strut constructs (including the dual-strut “sandwich” technique) have demonstrated union rates approaching 100% in focused series. At the same time, biomechanical and clinical data support their role in increasing construct stiffness and providing additional biology. In our practice, combining ICBG with decortication provided a strong baseline of biology; selective addition of onlay struts was reserved for femora with cortical deficiency, a long nonunion gap, or concern for bending/rotational rigidity—scenarios in which the literature suggests struts can be particularly advantageous.

The single nonunion in our series involved a patient with a retained Küntscher nail, treated only with Judet-style decortication and cancellous iliac crest bone grafting, without mechanical reinforcement. This case highlights that biological stimulation alone cannot compensate for insufficient construct stability. The Küntscher nail, an early unlocked design with limited torsional stiffness, provides inadequate control of rotation and bending under femoral loading, predisposing to persistent micromotion and fibrous tissue formation instead of bone bridging.

Numerous studies have emphasized the need to restore both biological and mechanical integrity in the revision of femoral shaft nonunion. Somford et al. [12] reported higher failure rates when unstable fixation was retained despite grafting. Furlong et al. [13] and Ha et al. [14] demonstrated improved outcomes when the nail was exchanged to a more rigid construct. Similarly, Cho et al. [6] and Guyver et al. [5] found that Judet decortication achieved optimal results only when coupled with stable fixation. More recently, Luo et al. [10] and Mohamed et al. [15] confirmed that augmentative plating or exchange nailing markedly enhances union compared with grafting alone.

Therefore, in revision cases using older-generation unlocked nails, mechanical augmentation—either exchange to an interlocking nail or addition of an augmentation plate—should accompany biological enhancement to achieve predictable healing and prevent recurrent nonunion.

Both nonunion cases in our series shared the common feature of insufficient mechanical reinforcement despite adequate biological stimulation. The first involved a retained Küntscher nail treated with Judet-style decortication and only cancellous iliac crest bone grafting. The second underwent plate replacement, but, similarly, only decortication and cancellous grafting were performed without onlay cortical strut augmentation. In both, the absence of improved fixation stiffness likely accounted for the persistent nonunion.

The Küntscher nail, as an early unlocked, slotted design, provides limited torsional and bending rigidity compared with interlocking systems or augmented constructs. Retaining such a nail may allow excessive micromotion at the nonunion site, inhibiting bone bridging despite biological support. Similarly, simple plate replacement without mechanical augmentation offers little improvement in construct stiffness if bone defects, cortical loss, or stress shielding remain. Studies have repeatedly emphasized that rigid fixation and biological enhancement must coexist for successful healing of femoral nonunion. Somford et al. [12] and Luo et al. [10] demonstrated superior outcomes with augmentative plating compared with exchange nailing when mechanical stability was optimized. Cho et al. [6] and Guyver et al. [5] reported that Judet decortication achieved its full benefit only under stable fixation. More recently, Mohamed et al. [15] confirmed that plate augmentation with retained nail achieved union rates approaching 100%, highlighting the value of mechanical synergy.

The present findings further support the use of cortical onlay strut grafts as a valuable adjunct in complex femoral nonunions. This technique provides a dual benefit—it enhances local osteogenesis through the biological activity of the graft while simultaneously increasing construct stiffness by acting as an external splint along the femoral cortex. Biomechanically, the strut functions as a tension band, improving both bending and rotational resistance. When combined with intramedullary fixation, the screws anchoring the iliac cortical strut often engage the retained nail, thereby creating an integrated bone-implant construct that markedly strengthens stability at the nonunion site.

Several authors have emphasized these advantages. Aslantürk et al. [4] demonstrated near-complete union rates using the dual-strut “sandwich” configuration, while Judas et al. [16] and Wu et al. [17] highlighted the technique’s ability to restore both biological and mechanical integrity in recalcitrant femoral nonunion. Thus, onlay strut grafting should be considered not only a biological procedure but also a mechanical augmentation, particularly beneficial in revision after intramedullary nailing, where additional rigidity is desirable.

This study has several limitations. First, its retrospective design may introduce inherent selection and information bias. Second, the study population consisted of patients referred after prior treatment at different institutions; therefore, detailed information on initial fracture characteristics—such as whether the fracture was open or closed, the degree of soft-tissue injury, and initial management protocols—was not consistently available. Third, the relatively small sample size of patients meeting the inclusion criteria may limit the generalizability of the findings. The absence of comparative statistical analysis between different treatment strategies is another limitation of this study. Smoking status and osteoporosis status were inconsistently recorded in the medical records and, therefore, could not be included in the analysis. The NonUnion Severity Score (NUSS) was not applied due to incomplete data inherent to the retrospective design. Instead, the Weber-Cech classification was used to reflect biological activity at the nonunion site. Additionally, the absence of a control group prevents direct comparison with other treatment strategies. Due to the study's retrospective design and the heterogeneity of prior treatments, a standardized control group could not be established. Therefore, it is not possible to determine whether the observed outcomes are attributable to biological augmentation, mechanical stabilization, or their combination. Despite these limitations, the present study provides valuable clinical insights into the effectiveness of a combined biological and mechanical approach in the management of aseptic femoral shaft nonunion.