Management of a bent tibial intramedullary nail following refracture: a case report and literature review

Introduction

Intramedullary nail (IMN) fixation has become one of the gold standards for the treatment of long bone fractures due to its advantages of central fixation and compliance with biomechanical principles, and is widely used in the clinical management of tibial fractures (1). However, secondary high-energy trauma may lead to the rare complication of refracture accompanied by IMN plastic deformation. According to the literature, the incidence of tibial refracture with IMN bending after initial surgery is low, and there remains controversy regarding the treatment of this complication. Common treatment options include closed reduction with in-situ retention of the implant (2,3), direct removal after closed reduction (4), direct removal of the bent IMN (5), and IMN extraction after truncation (6,7). Consensus on the indications and safety of different treatment methods has not yet been reached. Kose et al. proposed a critical angle of 20° for closed removal of bent IMNs through case studies, providing important clinical reference (5). A 2025 systematic review by Arif et al. indicated that various techniques are used for removing bent IMNs, and preoperative planning and instrument preparation are crucial for surgical success (8).

In clinical practice, such cases present a dilemma: attempting closed removal of the bent IMN may result in implant impaction or iatrogenic fracture, while osteotomy for IMN extraction increases patient trauma and the risk of postoperative complications (6,7). This article reports a case of a 28-year-old male with tibial refracture and IMN plastic deformation caused by high-energy trauma. The treatment strategy of “prioritizing fibular fixation, direct removal of the bent IMN, replacement with a new IMN” was adopted, and the patient achieved good functional recovery. This study aims to provide clinical reference for the diagnosis and treatment of this rare complication and further verify the safety and effectiveness of direct removal technology for IMNs with angulation <20°. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-282/rc).

Case presentation

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent for publication of this case report and accompanying images was not obtained from the patient or the relatives after all possible attempts were made.

A 28-year-old male patient sustained a right midshaft tibial fracture due to a soccer-related sprain 2 years prior. X-ray examination confirmed the fracture, and he underwent tibial IMN internal fixation at Foshan Hospital of Traditional Chinese Medicine (the original implant was a 9 mm × 330 mm titanium alloy IMN). On July 6, 2025, the patient was admitted to the Orthopedics Department of Foshan Hospital of Traditional Chinese Medicine as an emergency due to right leg swelling, pain, and limited mobility for 5 hours after a collision between his bicycle and a car.

Physical examination: there was swelling and deformity in the middle segment of the right lower leg, with muscle tension. Scattered skin abrasions were present on the right lower leg without exudation of blood or fluid. Old surgical scars were visible on the right knee and right ankle. Tenderness and longitudinal percussion pain were noted in the middle segment of the right lower leg, and bone crepitus could be felt on the lateral side of the middle lower leg. The range of motion of the knee and ankle joints was limited. The dorsal pedis and posterior tibial arteries were palpable, and the movement, blood supply, and sensation of the distal toes were normal.

Emergency X-ray examination was completed (see Figure 1): right midshaft to distal tibial refracture after internal fixation, slight separation of fracture ends with varus angulation, and the internal fixation IMN exhibited 13° lateral curvature in the coronal plane and 19° anterior angulation in the sagittal plane.

Figure 1 Preoperative anteroposterior (A,B) and lateral (C,D) views on July 6, 2025: refracture of the right distal middle tibia after internal fixation, with slight separation of the fracture ends and varus angulation; the internal fixation showed inward bending deformation. Fracture of the right distal middle fibula, with anterior-lateral displacement of the fracture ends and posteromedial angulation. (A,C) Knee joint; (B,D) ankle joint.

Diagnosis: refracture of the right midshaft tibia after internal fixation, and fracture of the right distal fibula.

Emergency physicians encountered difficulties in closed manual reduction, so the patient was admitted to the hospital for surgical treatment.

Relevant examinations were completed after admission, and a comprehensive assessment was conducted. Relevant preoperative examinations were completed, and surgical risks and difficulties were fully evaluated: first, the proximal locking screw of the IMN from the initial surgery penetrated the cortical bone, making nail removal difficult; second, after plastic deformation of the IMN, the contact between the IMN and the intramedullary canal changed from uniform linear contact to fulcrum contact at the bending apex, making retrograde extraction and extraction prone to secondary iatrogenic fracture; third, emergency tools such as metal cutting equipment needed to be prepared intraoperatively to address potential complications such as IMN breakage and impaction during removal.

After excluding surgical contraindications, the patient underwent open reduction and internal fixation of the right fibular fracture, removal of the right tibial internal fixation device, and closed reduction and internal fixation of the right tibial fracture on July 11, 2025. The preoperative appearance of the affected limb is shown in Figure 2. Intraoperative procedures: first, all screws and the IMN cap were completely removed through the original incision, and the bent IMN was extracted (see Figure 3, specification: 9 mm × 330 mm). Subsequently, an incision was made centered on the lateral fracture end of the right midshaft to distal fibula; after debriding the fracture end, open reduction and plate internal fixation of the fibular fracture were performed first to ensure the restoration and maintenance of leg length. Then, through a midline incision of the right knee, the intramedullary canal was gradually enlarged with reamers, and a 9 mm × 345 mm locked titanium alloy IMN was selected for closed reduction and internal fixation of the right tibial fracture. Flexion and extension of the knee and ankle joints were smooth. Postoperative X-ray re-examination (see Figure 4) showed satisfactory alignment of the fracture ends. At the 1-month follow-up in the outpatient clinic, X-ray showed callus formation. At the 2-month follow-up, the patient was able to walk normally on the ground. No complications such as infection, loosening of internal fixation, or joint pain occurred.

Figure 2 appearance photos on July 11, 2025.

Figure 3 The bent intramedullary nail removed during the operation on July 11, 2025.

Figure 4 Postoperative anteroposterior (A) and lateral (B) views on July 11, 2025: after revision internal fixation for the refracture of the right distal middle tibia, the fracture ends were well aligned. After internal fixation for the fracture of the right distal middle fibula, the fracture ends were well aligned.

Discussion

Mechanical mechanism of IMN plastic deformation

The biomechanical properties of IMNs are closely related to their material. Literature studies have shown that titanium alloy IMNs have better resistance to axial compression and axial rotation than stainless steel IMNs. However, under the action of secondary high-energy impact loads, titanium alloy IMNs are more prone to plastic deformation, while stainless steel IMNs tend to undergo brittle fracture (9). In this case, the original implant was a titanium alloy IMN, which underwent 13° curvature in the coronal plane and 19° angulation in the sagittal plane after high-energy impact. This is consistent with the failure mode characteristics of titanium alloy IMNs and aligns with the results of the aforementioned biomechanical studies.

Extraction strategy for bent IMNs and verification of the critical angle

Currently, there is no unified standard for the extraction of bent IMNs, and individualized decisions must be made based on factors such as IMN bending angle, material, diameter, fracture site, and healing status (10). The 20° critical angle proposed by Kose et al. (5) is a commonly used clinical reference: when the bending angle is <20°, the IMN can be directly removed using an impactor by leveraging its inherent elastic properties, avoiding additional bone damage; when the bending angle is >20°, closed reduction should be attempted first. If the residual angle after reduction is <20°, direct removal can be continued; if reduction fails, IMN truncation or longitudinal bone osteotomy is required.

In this case, the maximum angulation of the IMN was 19° (sagittal plane), which did not exceed the 20° critical value. The IMN was successfully removed directly using an impactor without implant impaction or iatrogenic fracture, further verifying the rationality of this critical angle. It should be noted that although closed reduction is an optional approach [e.g., Mousley et al. (2) reported a 2025 case of an IMN with 17° valgus and 5° retroversion deformity, where closed reduction avoided secondary revision], it carries certain risks: the elastic deformation of the IMN is limited after plastic deformation, and forced reduction may lead to IMN breakage; additionally, the application of external stress may cause traction injury to surrounding soft tissues, resulting in edema, bleeding, or even necrosis (9). The failure of emergency closed manual reduction in this case also confirms the operational difficulty and poor patient tolerance of closed reduction. Therefore, for cases with angulation close to 20°, direct extraction and nail exchange fixation may be a safer option.

Decision-making basis and comparative analysis of the treatment plan

The strategy of “prioritizing fibular fixation” was adopted in the treatment of this case: reduction and fixation of the fibular fracture can effectively restore leg length and alignment, providing a stable anatomical foundation for tibial fracture reduction and internal fixation, and avoiding postoperative functional disorders caused by abnormal limb length. In addition, a lengthened IMN was used postoperatively; the extended nail body increases the contact length with the intramedullary canal, enhancing fixation grip and stability, and reducing the risk of refracture.

Compared with alternative schemes reported in recent literature (2), the “closed reduction + in-situ retention of the IMN” was not selected in this case, mainly because the patient had tibial refracture with unstable fracture ends. Retaining the deformed IMN in situ could not provide sufficient fixation strength, failing to meet the biomechanical requirements for fracture healing; in contrast, IMN replacement optimizes the IMN specifications, achieving more reliable fixation and promoting fracture healing. A systematic review by Arif et al. (8) showed that “hook extractors”, “standard extraction techniques”, and “bone-holding forceps grasping” are common methods for removing bent IMNs. The standard impactor direct extraction technique used in this case is a clinically common and safe method. Its successful implementation relies on accurate preoperative assessment of the bending angle and IMN material, as well as precise control of operational force intraoperatively.

Study limitations and clinical recommendations

This case has the following limitations: first, the follow-up period is short (2 months). Although the patient achieved good short-term functional recovery, long-term outcomes such as solid fracture healing, knee joint function, and long-term stability of the internal fixation require further follow-up observation; second, the complete mechanical parameters of the original IMN were not recorded in detail, which may affect the analysis of extraction thresholds for IMNs of different materials and diameters.

Based on the experience of this case and literature review, the following clinical recommendations are proposed: (I) preoperative imaging examinations should be completed to accurately measure the IMN bending angle, assess fracture healing status, clarify the IMN material and specifications, and formulate an individualized extraction plan; (II) emergency tools such as metal cutting equipment should be prepared intraoperatively to address potential complications such as IMN breakage and impaction during removal; (III) for cases of tibial refracture with IMN plastic deformation and angulation <20°, direct extraction + IMN replacement fixation should be prioritized, with simultaneous fibular fixation to maintain limb length; (IV) postoperative follow-up should be strengthened to monitor fracture healing and functional recovery, and the rehabilitation plan should be adjusted in a timely manner.

Conclusions

In conclusion, the treatment strategy of “prioritizing fibular fixation + direct extraction of the bent IMN + replacement with a new IMN” is safe and effective for tibial refracture combined with IMN plastic deformation (angulation <20°), which validates the rationality of the 20° critical angle for closed extraction. In the future, more case accumulation is needed to clarify the removal thresholds of IMNs of different materials and at different positions, and to optimize the treatment strategy for IMN complications after high-energy trauma.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-282/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-282/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-282/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent for publication of this case report and accompanying images was not obtained from the patient or the relatives after all possible attempts were made.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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