Percutaneous Kirschner wires with mutual linking technique in the management of proximal humeral fracture

INTRODUCTION

Proximal humeral fracture (PHF) is a relatively common fracture, accounting for 6% of all fractures. Its incidence is increasing with time due to the population’s increasing longevity.^[1] There are several approaches to treating these fractures, and a debate still exists regarding the best treatment modality.^[1]

Conservative management remains the gold standard for the majority of PHF. However, considering the patients’ functional and physiological status and fracture severity, many cases can be managed operatively.

There are many options for operative treatment of displaced unstable fractures in the elderly, including closed reduction and percutaneous pinning (CRPP), open reduction and internal fixation (ORIF) by plate and screws, intramedullary nails, and arthroplasty.^[2] CRPP is considered a minimally invasive approach, avoiding aggressive surgical dissection as in ORIF and minimizing the risk of humeral head avascular necrosis (AVN). It is preferred when treating elderly patients with multiple comorbidities to minimize the surgical burden and hospital stay. However, it has some complications, such as loss of the fracture reduction during follow-up and pin migration.^[3]

Therefore, in this study, we hypothesized that using a modified technique of percutaneous K-wires with mutual linking would provide a better functional and radiological outcome and avoid the complications associated with the standard CRPP. This study aimed to introduce a novel technique to enhance the stability of CRPP, providing a suitable minimally invasive option for the management of PHF in elderly patients.

MATERIALS AND METHODS

A prospective cohort study was held from March 2024 to March 2025. The authors recruited 30 patients according to the following inclusion criteria: Both sexes, age ranging from 60 to 80 years, with two or three-part fractures according to Neer classification and suffering from acute injury (<3 weeks).^[1] We excluded patients with four-part fractures, as these could translate to the need for anatomical reduction or arthroplasty, which increases the risk for AVN or worse functional outcomes, and those with a history of previous shoulder surgeries or pathologies that affected their shoulder range of motion.

The patients were assessed preoperatively through a detailed medical history, general and local examinations, routine pre-operative laboratory tests, and plain radiographs of the shoulder, showing the humerus in anteroposterior and lateral views.

Surgical technique

All patients were positioned in the beach chair position and underwent closed reduction of the fracture by gentle traction and manipulation. Minimally invasive reduction techniques, such as joystick wires, can be used to reduce difficult fracture patterns. Fixation by four to six K-wires (diameter 2–2.5 mm), two parallel K-wires were inserted from the greater tuberosity and engaged in the medial cortex of the humeral shaft, passing through the fracture site and fixing it. Another two parallel K-wires were inserted from the lateral cortex of the humeral shaft and engaged to the calcar portion of the humeral head to add stability. Additional K-wires can be inserted intramedullary if more stability is needed. Then, the K-wires were bent away from the skin by at least 1 cm to avoid irritation and they were then mutually hooked together with suitable tension to function as a single construct. To add stability to the wire links, rubber cerclage bands can be used [Figure 1].

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Figure 1:

(a) Pre-operative plain radiograph showing a three-part fracture of the humerus, (b) fixation by five K-wires, (c) the mutual linking technique, and (d) plain radiograph showing union after removal of K-wires.

Export to PPT

Patients were reviewed after 2 weeks to ensure the reduction was maintained and to check for any pin tract infection. Follow-up was conducted every month for the first 6 months, then every 3 months until the end of the study (1 year). As the last patient was operated on in May 2024, the follow-up time ranged from 10 to 12 months, with a mean of 11+/−0.83 months. Regarding the rehabilitation protocol, elbow range of motion was encouraged from day 1 postoperatively, and physiotherapy started at 3 weeks postoperatively. Removal of the wires was at 6 weeks, except for two patients with delayed union, who had their wires removed at 8 weeks postoperatively.

The primary outcomes were functional shoulder assessment and radiological assessment of the fracture union. The secondary outcome was to determine the rate of complications, such as nonunion, loss of reduction, humeral head osteonecrosis, and pin migration.

Functional assessment was performed using the American Shoulder and Elbow Score (ASES) and the University of California, Los Angeles (UCLA) Shoulder Rating Score. Assessment of fracture union was done by plain radiographs of the shoulder, AP, and lateral views.

RESULTS

Regarding the demographic data, 30 patients were enrolled in our study, with a mean age of 69.2 years. The study comprised 60% (18) females and 40% (12) males. Regarding the medical comorbidities, 40% were medically free while 60% had different comorbidities such as diabetes mellitus, hypertension, stroke, and cardiac conditions. Sixty percent of the patients had a two-part fracture, according to the Neer classification, while 40% had a three-part fracture, as shown in Table 1.

Regarding the follow-up data: The mean visual analog scale (VAS) score was 1.9 at 6-week follow-up and improved to 0.37 (range from 0 to 3) at 11 months follow-up, which was statistically significant (P < 0.001).

All shoulder functional scores (UCLA and ASES) improved significantly from 6 weeks (mean UCLA shoulder score = 27.67 and mean ASES = 80.93) to 11 months follow-up; the mean ASES was 93.27/100, while the mean UCLA shoulder score was 32.87/35 at 11 months follow-up. The mean abduction angle was 166.7°, while the mean forward flexion angle was 168.7° at 11 months follow-up.

Twenty-eight patients (93.3%) achieved initial radiological signs of union at 6 weeks, while 2 patients (6.7%) achieved initial radiological signs of union at 8 weeks.

Regarding complications, 1 patient (3.3%) had a pin tract infection, while another patient (3.3%) had loss of reduction of the fracture. No pin migration, nonunion, or humeral head AVN was detected [Table 2].

DISCUSSION

Standard CRPP and ORIF using the proximal humerus internal locking osteosynthesis (PHILOS) plate are two reliable methods for fixing PHF. CRPP is an efficient treatment option with the advantages of minimizing soft-tissue dissection. However, fixation with a locked plate is more mechanically sound and offers stable fixation.^[4]

By reviewing the literature regarding the results of the standard CRPP, Keener et al.^[5] reviewed 35 patients. The time to union was 2 to 3 months, with a mean VAS of 1.4, and an ASES score of 83.4. Complications included four cases of malunion, four cases of osteoarthritis, and one case of pin tract infection. Fixation by K-wires with the mutual linking technique yielded superior results, as the time to union was shorter than that of the standard technique (6–8 weeks). Better functional scores were also achieved (ASES 93.27, UCLA 32.87).

Jaberg et al.^[6] reviewed 48 patients, with a time to union of 8 weeks. They reported a functional outcome of 70% satisfaction. Complications included loss of reduction in four cases, two cases of pseudoarthrosis, four cases of pin tract infection, one case of deep infection requiring debridement, and two cases of AVN.

Fenichel et al.^[7] reviewed 50 patients and reported a functional outcome of 70% satisfaction. The complications included five cases of loss of reduction and five cases of pin tract infection.

Herscovici et al.^[8] reviewed 40 patients, with a time to union of 2.6 months; they reported an almost 100% failure rate when using smooth K-wires and recommended the use of threaded wires. In addition, they suggested managing types two and three only with this technique, as the rate of complications increased for type four. In our study, smooth K-wires were used and achieved good results; we recommend using the threaded wires in severely osteoporotic patients.

Therefore, managing the PHF with K-wires using a mutual linking technique yielded superior results compared to the standard CRPP, as evidenced by shorter time to union, better functional outcomes, and a lower rate of complications.

Geiger et al.^[9] reviewed 28 patients using fixation by the PHILOS technique and reported complications of AVN in two cases and impingement in six cases. While Shahid et al.^[10] reviewed 50 patients, the time to union was 8 weeks, and they reported complications, including one case of nonunion, one case of shoulder stiffness, and two cases with a protruded intra-articular screw. Doshi et al.^[11] reviewed 53 patients, with a median time to union of 12 weeks. Forty-four patients had an excellent to good functional outcome. Reported complications included loss of reduction in two cases, three cases with screw back out, and one case of superficial infection managed with antibiotics.

Therefore, managing PHF with ORIF using the PHILOS technique yielded comparable results to the technique of K-wires with mutual linking, while also having the advantage of avoiding potential complications associated with plating and screws, such as marked soft-tissue dissection, humeral head AVN, screws backing out, and shoulder impingement due to superior plate position.

There were several techniques in the literature to improve the stability of the K-wires as the minimally invasive reduction and osteosynthesis system described by Carbone et al.^[12] This device allows for fracture fixation using K-wires secured in a metallic clip. However, this device is limited to the use of only four K-wires and in a fixed direction, as allowed to be locked by the metallic clip, unlike the technique of mutual linking, which allows the use of an infinite number of K-wires and in any needed direction according to the fracture configuration. Another technique was used to improve that the stability of K-wires was the humerus block technique described by Bogner et al.,^[13] two K-wires are crossed to fix the fractured fragment through a metal block fixed to the humeral shaft by a cannulated screw; however, this technique is also limited by the use of only two K-wires and in a fixed direction unlike the technique of mutual linking.

To the best of our knowledge, this study is the second after Chang et al.^[14] to apply this novel technique in the management of PHF. However, this study was prospective and recruited a larger sample size (30 patients) compared to Chang et al. (six patients) to get more reliable results.^[13]

The limitations of this study were a relatively small sample size, the lack of comparison with other methods of fracture fixation, short follow-up period to detect osteonecrosis as it could happen up to 3 years, and the relatively large margin of error (15%); however, it reflects the variability inherent in clinical outcome measures and the early stage nature of this novel technique evaluation.

CONCLUSION

Percutaneous K-wires technique with mutual linking is a reliable method in the management of PHF with good functional and radiological outcomes, keeping the advantages of the standard CRPP as minimal soft-tissue dissection and low cost and with enhanced mechanical stability, offering a stable fracture reduction till union.