1 Introduction

Ankle fractures are among the most common injuries encountered in orthopedics. These fractures are often considered suitable for resident-level procedures, with open reduction and internal fixation (ORIF) remaining the most effective treatment for most cases.¹ Lateral malleolus fractures are classified into Weber types A, B, and C based on the location of the fracture line, with Type A fractures occurring lower on the ankle, making internal fixation more challenging. Clinically, Type A fractures can be treated using screws, Kirschner wire tension bands, or hooked plates, and generally have a favorable prognosis.² Surgical intervention has been shown to be superior to non-surgical treatment for ankle fractures in geriatric patients.³ However, osteoporosis and the presence of diabetes mellitus and other underlying conditions can make internal fixation relatively difficult.

Kirschner wire tension band technique is simple to operate and cost-effective, and it also conforms to the biomechanical principles of the lateral malleolus. However, it has poor resistance to rotation and shear, and the steel wire knot, located under the skin, is easily palpable and can irritate, which poses a high risk of a second surgery to remove the internal fixation. Conventional screw internal fixation can effectively compress and stabilize the fracture ends, with minimal trauma, but there is a risk of internal fixation failure and screw back-out. Plate internal fixation is more suitable for patients with severe osteoporosis, achieving strong internal fixation, but it requires extensive soft tissue stripping, which can disrupt blood supply. The thin soft tissue at the lateral malleolus makes larger internal fixations more likely to cause patient discomfort.⁴ For strong fixation and reduced incision length, the authors used two screws combined with absorbable sutures to construct a self-compression tension band system to treat lateral malleolus fractures in geriatric patients, as reported below.

2 Methods

2.2

2.2 Surgical protocol

Following successful anaesthesia, patients were placed in the lateral decubitus position, routinely disinfected and towelled. A lateral incision was made to expose the fractured end of the distal fibula. The haematoma, granulation tissue hyperplasia and bone scab were cleaned up, followed by repositioning under direct vision. A Kirschner wire was used for temporary fixation. Guide pins were then inserted anteriorly and posteriorly into the distal fibula. After confirming the satisfactory position of the guide pins, two 3.0 mm hollow nails were screwed into the guide pins (Wright, USA), the nail tails were not pressurized at this time. A 2.0 mm pin was used to drill the proximal fibula. A no. 0 double-stranded Vicryl suture (COVIDIEN, USA) was then employed to create a figure-of-8 tension band around the ends of the nails. After tying a “Nice” knot, pressure was applied to the nail ends, resulting in satisfactory compression of the fracture ends (Fig. 1)Any additional fractures encountered will be addressed accordingly.

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Fig. 1 Schematic diagram of the surgical procedure: (a) Exposure of the fracture end; (B) Cleaning of the broken end; (C) Screws and suture placed; (D) Tightening of the screw.

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2.3

2.3 Postoperative treatment

Immediately after the operation, ice compresses were applied to reduce swelling. They were supplemented with anti-swelling and pain relief medication. The sutures were removed after the incision completely healed, typically within 2 weeks post-operation. For complicated ankle fractures, the patient may be immobilized with a plaster cast or inflatable support for 3–6 weeks. Non-weight-bearing rehabilitation started immediately after surgery, and partial weight-bearing training began at 6 weeks based on the X-ray, with full weight-bearing determined at 12 weeks post-surgery (Fig. 2).

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Fig. 2 Radiograph imaging: (a b) Preoperative CT; (C) 6 weeks postoperative.

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3 Results

There were a total of 31 patients with Weber type A lateral malleolus fracture, including 18 males and 13 females, (65.6 ± 7.3) years of age, 14 cases on the left side and 17 cases on the right side. Causes of injury: 17 cases of sprain, 8 cases of traffic accident, 4 cases of sports injury, 2 cases of fall injury. Combined injuries included medial malleolus fracture, fifth metatarsal base fracture, medial ankle fracture and ankle ligament injury, and underlying diseases included hypertension, diabetes, smoking and postoperative malignancy (Table 1).

All 31 patients in our group were completely followed up for 12–36 months (mean 19.5 months). The average operation time was (44.7 ± 13.6) min, slightly longer in patients with other injuries combined, and intraoperative bleeding less than 10 mL was not included in the calculation. Regular postoperative review of X-rays and CT scans showed that the fracture healed within 8–16 weeks, with an average of 12.3 weeks. There were no signs of delayed healing, nonunion, internal fixation loosening, or fixation failure. On postoperative complications, one patient with superficial infection was cured by antibiotics and dressing change. Other complications included one case of numbness, which was treated with methylcobalamin; one case of foreign body sensation, where the screw head could be visibly felt on the body's surface and was subsequently removed; and one case of prolonged pain, which was managed with pain-relieving patches. At the final follow-up, the AOFAS score was (89.8 ± 6.2) points, the VAS score was 0 (18 cases), 1 (11 cases), and 2 (2 cases), and the ankle range of motion (ROM) was 65.4 ± 4.3°, with a clinical satisfaction rate of 87.1 %.

4 Discussion

In this study, the use of screws in combination with absorbable sutures to construct a tension band effectively ensures compression of the fracture ends and eliminates the need for removal of internal fixation. This approach demonstrated a favorable prognosis and is particularly suitable for older patients, who are more prone to infections.⁵

Ankle fractures often result in shortening, which, along with displacement or angulation of the ankle, can significantly alter the stress distribution across the ankle joint.⁶ These changes can contribute to the development of traumatic osteoarthritis.⁷ Conservative treatment often results in a low satisfaction rate; therefore, surgical treatment remains the most effective approach for lateral malleolus fractures.⁸ In a clinical study of patients with ankle fractures, there was no statistically significant difference in clinical and radiographic outcomes between 1/3 tubular plates and anatomical locking plates of the lateral ankle in terms of clinical and radiologic outcomes, complication rates, and time to fracture healing.⁹ In addition, Kirschner wires, tension bands, and screws are commonly used for internal fixation. Screw internal fixation is simple and fast, intraoperative stripping of periosteum and soft tissue is minimal. This can effectively prevent the destruction of soft tissue, reduce intraoperative bleeding, and make it a safer internal fixation method. Considering the increasing activity requirements of older patients and the poor bone quality, the authors combined for the first time two screws and absorbable suture tension band techniques to ensure strong fixation of the fracture block and to increase the pressure between the blocks.

The tension band technique facilitates the healing of fracture ends by converting tension at the fracture site into compression. This method has the advantages of reducing periosteal stripping, being straightforward to apply, and being cost-effective, making it a common choice, particularly for avulsion fractures. Typical applications include the patella, olecranon,¹⁰ base of the 5th metatarsal,¹¹ and the distal tibia's Chaput bone block.¹² When used for lateral ankle fractures, Kirschner wire tension bands can provide satisfactory internal fixation, align with the biomechanics of the lateral ankle, and promote functional recovery and early mobilization.¹³ However, Kirschner wire tension bands have notable drawbacks, such as limited torsional and shear resistance, leading to a higher incidence of internal fixation failures. Consequently, the use of simple Kirschner wire tension bands has decreased in clinical practice. Additionally, conventional Kirschner wires are not demagnetized, which may interfere with subsequent MRI examinations. Nearly all patients required a second surgery to remove the wires, increasing the risk of systemic complications, particularly in older patients. In contrast, the current study employed two screws, which do not require removal unless absolutely necessary. If removal is needed, it involves only a minor skin incision at the entry point, resulting in minimal trauma and reduced patient discomfort.

Regarding the choice of tension band materials, 1 mm steel wire is commonly used, but absorbable sutures are also applied effectively. A cadaveric study by Adjal et al.¹⁴ compared sutures and metallic materials in 19 cases and found no statistically significant difference in biomechanics between the two groups, which aligns with the findings of this study. Absorbable sutures offer advantages over steel wires, such as reducing implant-related complications. Steel wires can cause soft tissue irritation and patient discomfort due to their knotted nature and stronger cutting action. In contrast, sutures are more flexible and less irritating than traditional wires, leading to smoother handling and eliminating the risk of intraoperative suture breakage, which can occur with wires under pressure. Vicryl sutures retain approximately 80 % of their initial strength for up to 2 weeks. By this time, most patients have achieved initial stability, and any decrease in tension band strength has minimal impact on fracture healing. Our clinical observations confirm the efficacy of this approach.

We utilize hollow nails with tail caps for this procedure. During the insertion of the tail cap, the suture is subjected to outward expansion forces, creating a pressurized effect. To optimize this, we first avoid fully tightening the screws, instead securing the suture with a Nice Knot. Subsequently, we alternate tightening the screws and apply final pressure.The screws should be parallel to each other and as perpendicular to the fracture line as possible to ensure effective compression. Using a double-stranded suture threaded through the fibula enhances the tension band's effect and reduces cutting stress. The Nice Knot, known for its effectiveness in reducing comminuted patellar fractures and commonly used in cases requiring indirect suturing, further secures the suture.¹⁵

The tension band technique should be applied based on specific indications. We recommend this method primarily for Weber type A fractures and certain type B fractures of the lateral ankle, especially for transverse fractures. For oblique fractures, it is crucial to orient the screws as perpendicular to the fracture line as possible. This technique is unsuitable if the fracture line is so oblique that the screw tails are not level and the sutures may dislodge from the screw tails. In younger patients with good bone quality, direct screw fixation alone is generally sufficient. However, in older patients, preoperative assessment of osteoporosis through bone densitometry and X-rays is essential. If severe osteoporosis is confirmed, the tension band technique may not be appropriate due to the risk of sutures cutting through the bone. In such cases, using a small plate for fixation is a safer alternative.

5 Limitations

This study has several limitations. Firstly, it consists of a series of case reports and lacks a comparison with other internal fixation methods, which limits the ability to fully assess the effectiveness of this procedure. Secondly, in patients with severe osteoporosis, suture tension bands may experience cutting through the bone, which restricts the procedure's applicability. Lastly, the procedure requires specific fracture orientations, with transverse fractures being the most suitable indication. Future research involving larger multicenter studies is needed to confirm the efficacy of this technique and to better define its scope of application.

6 Conclusion

The screw combined with suture self-compression tension banding technique is simple and reliable in the treatment of Weber A type lateral malleolus fractures in geriatric patients. This technique is worth considering for fractures at other locations as well.

CRediT authorship contribution statement

Zhendong Li: Acquisition of data, Analysis and interpretation of the data, Drafting of the manuscript. Haichao Zhou: Acquisition of data. Youguang Zhao: Analysis and interpretation of the data. Jiang Xia: Study design. Yunfeng Yang: Study design, All authors contributed to the review and revision of the manuscript.

7 Ethical approval

This study was approved by the Institutional Review Ethics Committee of the Shanghai Tongji Hospital (K-W-2021-015). All methods were carried out in accordance with relevant guidelines and regulations of Institutional Review Ethics Committee of the Shanghai Tongji Hospital.

Funding

The study was sponsored by Key Research and Development Program of the National Ministry of Science and Technology (2022YFC2009505); Shanghai Committee of Science and Technology(22S31900300).