Introduction

Femoral shaft fractures account for 4.6 % of all adult fractures [1] and the majority require surgical treatment. Traction table-based intrameduallary (IM) nail fixation is often employed as an established and accepted treatment method for adult femoral shaft fractures [2]. A key factor for successful treatment of femoral shaft fracture is to achieve anatomical or nearly anatomical reduction. However, difficulty exists in the reduction of femoral shaft fractures [3]. Additionally, various complications associated with traction tables have also been reported, such as pudendal nerve injury and foot traction injury [4–10]. To improve the reduction quality and lessen the risk of traction table-associated complications, a novel instrument, the rapid reductor for lower limb fractures and its technique of obtaining and maintaining reduction, has been invented and employed herein to facilitate skeletal-traction-based closed reduction and IM nail fixation for femoral shaft fractures. The purpose of this study was to assess the outcomes of displaced femoral shaft fractures treated by closed reduction and IM nail fixation with the assistance of the rapid reductor.

Patients and methods

Patients with displaced femoral shaft fractures treated in our department between November 2012 and March 2013 were recruited into this study. The inclusion criteria were age >18 years old and unilateral displaced femoral shaft fracture without other fractures in the lower extremities. The exclusion criteria were as follows: open fractures, pathological fractures, patients who did not consent to the use of the rapid reductor or were unable to apply the device due to poor local skin conditions, severe medical complications, and other associated severe injuries such as traumatic brain injury.

Twenty-two patients (22 fractures) met the inclusion criteria, including 13 males and nine females with an average age of 31.3 years (range, 21–42 years). According to AO/OTA classification, fracture patterns included type 32-A in four cases (Fig. 1), type 32-B in 13 cases, and type 32-C in five cases. After hospitalization, the patients underwent a preoperative examination and preparation. Operations were performed two to five days after initial injury.

Fig. 1
figure 1

A 50-year-old patient sustained a left displaced femoral shaft fractures. a Antero-posterior view. b Lateral view

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The Institutional Review Board of the local hospital approved this study after a thorough examination. Signed informed consents were obtained from all the patients. The study was performed in accordance with the ethical standards of the Declaration of Helsinki from 1964.

Surgical technique

The rapid reductor is primarily composed of a reduction scaffold, traction bow, traction pin, connecting rod, auxiliary reduction pin (Schantz pin or Kirschner wire) and proximal connecting device (Fig. 2). The patient was placed in a supine position with a soft padded cushion under his/her buttock. Disinfectant preparation covered the anterior superior iliac spine (ASIS) until to the proximal 1/3 of the tibia. A 0.5-cm incision was made over the ipsilateral ASIS, and a Schantz pin 5-mm in diameter was screwed into the superior cortex at a 30–45 degrees angle to the horizontal plane and was connected to the proximal end of the connecting rod via a cardan shaft. The connecting rod with proper length was selected to accommodate different patients. The distal end of the rod was connected to the reduction scaffold, which straddled the lower leg. The scaffold maintained a traction position during the operation, and its four legs were adjustable to optimize the support height. Traction via femoral condyle or tibial tubercle was then performed. The traction bow was connected to the rotary screw of the scaffold (Fig. 3). After confirming that all parts of the redactor were securely joined, a closed-loop mechanical traction system was formed by connecting the ilium, hip joint and distal femur to the reductor. Under fluoroscopic guidance using the C-arm on anteroposterior (AP) and lateral views, the fracture can be reduced using the rapid redactor. The reductor screw was rotated to pull the femur distally, thereby correcting the overlapping displacement of fracture (Fig. 4a). The crossbeam that the screw was attached to could rotate around its long axis to ensure precise traction direction control. The connecting rod had vertically-drilled holes to assist in the reduction of anterior-posterior displacement by accommodating a lag screw or Kirschner wire. The bilateral frame could slide on the connecting rod. For lateral displacements, a Schantz pin or Kirschner wire was inserted through a tapped hole on the lateral frame into the femur to reduce fracture with a “joy stick” technique. For fractures with rotational deformity, the traction bow could be rotated accordingly to facilitate reduction. The cable method [11] and the linear relationship between the morphological alteration of the lesser trochanter and femoral rotation [12] were used for intra-operative evaluation of rotational alignment. After achieving satisfactory reduction, as revealed by C-arm examination, the reductor remained in the reduction position. A suitable IM nail was implanted via a minimally invasive approach to fix the fracture (Fig. 4b). The operative time, reduction time, fluoroscopy time, and intra-operative blood loss were recorded.

Fig. 2
figure 2

The photos of a rapid reductor. a Overlooking view. b Lateral view

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Fig. 3
figure 3

The rapid reductor is connected to the ASIS via its proximal end and to the proximal tibia via its traction bow at the distal end, and a mechanical closed-loop traction system is formed

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Fig. 4
figure 4

The reductor screw was rotated to pull the femur toward its distal end, thereby reducing the overlapping fracture (a). The intramedullary nail was inserted to fix the fracture (b)

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Postoperative management

After the operation, radiographs of the affected femur were taken to assess the reduction and fixation quality of the fractures. Patients were encouraged to perform isometric quadriceps exercises on the first day postoperatively and crutch-assisted walking on the second day. Partial weight-bearing began six weeks postoperatively. According to the radiographic assessment of fracture healing, full weight-bearing was allowed, usually at three months postoperatively. Follow-up was conducted at one, three and six months after the operation and every half year thereafter. Radiological and clinical evaluation was performed at each follow up. The alignment of the lower extremity was assessed using a cord which was stretched straight from the ASIS to second metatarsal to observe whether the cord passed through the midpoint of the patella [13].

Results

Using the rapid reductor, all 22 cases of displaced femoral shaft fractures were reduced in a closed fashion, and none converted to open reduction. The rapid reductor can maintain fracture reduction during the IM nailing procedure. After IM nailing, the patients exhibited excellent alignment in the injured limb and no residual malreduction or angular malalignment was shown on the fluoroscopic images. All operations were performed without complications. Neither reductor-induced neurovascular injury nor Schantz pin-induced ilium splitting occurred. The average operative time, fracture reduction time, fluoroscopy time and blood loss were 58 minutes (range, 43–95 minutes), 9.1 minutes (range, 6–15 minutes), 13.2 seconds (range, 4.5–41.0 seconds) and 87 mL (range, 60–150 mL), respectively. Postoperative AP and lateral radiographs of the injured femur revealed that satisfactory fracture reduction and fixation had been obtained.

Twenty-two patients were followed up for an average of 20.3 months (range, 18–22 months). One patient developed a superficial incision infection, which was successfully treated with dressing changes. One patient suffered deep vein thrombosis of the lower limb. Nonetheless, all the patients displayed postoperative fracture healing; the healing time ranged from four to nine months (median six months). No cases of malunion or non-union occurred. At the latest follow-up, the muscle strength of the affected limbs was similar to the contralateral ones. There was neither limb length discrepancy nor observable ASIS-patellar midpoint–2nd metatarsal malalignment in any patient. Two patients reported pain in the area above the knee with a visual analog scale score of 1. None requested further treatment.

Discussion

In the present study, we treated displaced femoral shaft fractures with the rapid reductor-assisted closed reduction and IM nail fixation. The rapid reductor can not only reduce fracture but also maintain it in an anatomical position. The rapid reductor-related complications did not occur during the operation. All fractures healed well and satisfactory functional recovery was achieved in each patient.

IM nail fixation assisted by a traction table has become a standard procedure for treating femoral shaft fractures in adults [2, 14]. However, there are some weaknesses of the traction table-based reduction technique. During the operation, persistent pulling through a boot and resistance from the perineum post generate a force for lower limb fracture reduction. In case of young adult patients or old femoral fracture, a larger force is needed to reduce fracture; however, prolonged traction with a large force may lead to stretch injury of the foot, pudendal nerve trauma, perineal ulcers, peroneal nerve palsy and compartment syndrome [4–10]. Some surgeons may prefer to not use a fracture table even if not contraindicated for other reasons [15]. Several tools and techniques have been employed to achieve fracture reduction for IM nailing of femur fractures [3], including reduction finger [16], femoral distractor [17, 18], a “F-tool” [19] and a fracture reducer [20, 21]. However, no single technique can work in every situation. Our team invented the rapid reductor for lower limb fracture reduction, by taking the above-mentioned reduction tools as references and with the aim to avoid complications associated with the traction table-based reduction technique.

Different from skin traction with the use of a traction table, skeletal traction is applied using a rapid reductor. The rapid reductor is connected to the ASIS via a Schantz pin and to the distal femur via its traction bow. Correspondingly, a mechanical closed-loop system is formed. Skeletal traction can generate enormous force to reduce displaced fractures more effectively. The traction force is resisted by the force pulled on the ASIS via the connecting rod. Hence, there is no need to employ a perineum post to counteract the pulling force of skeletal traction, which can avoid the complications associated with the traction table. In the present study, no case of peroneal nerve palsy, perineal ulcers or nerve damage was reported. These complications did not occur in the series of patients treated with the rapid reductor.

The rapid reductor can correct overlapping, anterior-posterior and lateral displacement of femoral fractures via traction and via inserting a Schantz pin into the femur used in a joystick technique. Rotational deformities can be reduced by rotating the traction bow inward or outward. Ciftdemir et al. applied the electromagnetic-manual guided distal locking technique to prevent malrotation in femoral shaft fractures treated using IM nails [13]. Using the rapid reductor, all 22 displaced femoral shaft fractures exhibited anatomical or nearly anatomical reduction. The rapid reductor can also maintain femoral fracture in an anatomical position for IM nail fixation. During the operation, residual malreduction, angular malalignment, or malrotational deformity were not noted after IM nail fixation. At follow ups, no case of malunion, non-union or limb length discrepancy was observed. The rapid reductor is solidly connected to the injured limb but does not hinder ipsilateral adduction or abduction as needed for operative procedures such as reduction, fluoroscopic examination and IM nailing. In addition, a leg with the reductor in place can be lifted and greatly facilitate IM nailing with different body positions, which is also a major advantage of this device. In contrast, using a traction table demands a relative fixed body position. This limitation of the traction table may impair reduction quality in certain cases of inwardly angled fractures as well as IM nailing in overweight patients.

Compared with the traction table-based reduction and IM nailing technique, the rapid reductor is easy to perform and effective to reduce fracture and maintain its realignment, which results in shorter operative time and fluoroscopy time with less blood loss. In the present study, the average operative time, fluoroscopy time and blood loss were 58 minutes, 3.2 seconds and 87 mL, respectively. In a previous study also conducted by our team [22], 74 adult patients with femoral shaft fractures were treated by traction table-assisted reduction and IM nail fixation, including 63 fractures reduced in a closed fashion and 11 treated by open reduction. The average operative time, fluoroscopy time and blood loss were 66 minutes (range, 45–118 minutes), 18.7 seconds (range, 5.0–47.0 seconds) and 216 mL (range, 120–580 mL), respectively, which were more than the corresponding data in this study. The rapid reductor is cheap to purchase. Each set costs 3500–5000 RMB, making it a convenient alternative in primary hospitals which lack a traction table due to the relatively expensive price, especially in the developing countries.

This study has several limitations. This study is limited by its retrospective nature. The study has a small sample size that did not enroll cases who sustained other fractures of the ipsilateral lower extremities in addition to femoral shaft fractures. We did not include cases treated by traction table-based reduction and IM nailing as a control group. Another limitation is that the rotational deformity of the femur was not measured quantitatively at follow ups. In a future study, we will recruit more patients with a control group undergoing conventional treatment and do more quantitative measurements to thereby further investigate the efficacy of the rapid reductor in treating displaced femoral fractures.

Conclusion

Displaced femoral shaft fractures in adults can be treated by the rapid reductor-assisted closed reduction and IM nail fixation. The rapid reductor can both reduce displaced femoral shaft fracture and maintain it in an anatomical position, which is conducive for successful IM nailing fixation. This technique is easy to perform with excellent functional recovery and rare reductor-related complications.