Introduction
Acetabular fractures commonly affect young adults after high-energy trauma. An isolated posterior wall fracture is the most common type, accounting for 20–35% of cases, with a reported incidence of intraarticular incarcerated fragments occurring in up to 8% of the cases [
1‐
4]. Obtaining anatomical acetabular fracture reduction is paramount, as imperfect reduction or leaving loose fragments intraarticularly could fasten the development of post-traumatic secondary osteoarthritis [
5‐
9].
These fractures are usually challenging to treat owing to their complex anatomy and associated injury patterns, such as the presence of joint surface impaction injuries and intraarticular incarcerated fragments; even more, the complexity is aggravated when dealing with muscular or obese patients [
6,
7], so a lot of reduction techniques and tools were suggested to facilitate the management [
10].
For intraarticular incarcerated fragments and in cases associated with marginal impaction injuries, it is better to treat these injuries under direct vision, which is usually tricky due to the anatomical nature and concavity of the hip joint [
4,
11,
12]. Various techniques were used to facilitate this process, including hip dislocation, which could further add to the soft tissue envelop injury and cause traction on the sciatic nerve [
12,
13]; some surgeons suggested hip arthroscopy [
14,
15]; however, this needs special equipment, training, and could be associated with specific complications such as neuropraxia, perineal soft tissues injuries, and ankle joint pain [
16,
17].
To avoid the drawbacks and limitations of the previous techniques, joint distraction had been introduced as a practical option; this could be achieved through various techniques, either by operating on a traction table; however, if such a table was not available, surgeons either use manual traction or various tools such as the AO large femoral distractor to assist joint distraction [
18,
19].
The AO large femoral distractor was used to reduce various fractures at different anatomical locations, such as femoral fractures [
13,
20], tibial fractures [
21], and calcaneal fractures [
22]. It was reported as an assisting tool during acetabular fracture surgery [
18,
23].
This study aimed to evaluate and report our experience using the AO large femoral distractor as an assisting tool to obtain anatomical reduction assessed in postoperative plain radiographs, and CT scans in acetabular fractures associated with marginal impaction or intraarticular incarcerated fragments.
Discussion
In most cases, surgical treatment for acetabular fractures is needed to achieve anatomical reduction and restore the congruency and stability of the joint [
2,
11]. One keystone element of the surgical technique is optimum visualization, which is usually tricky due to limited access while the hip joint is in a reduced position; this could be eased through a limited distraction of the hip joint using a large femoral distractor [
18,
23].
In the current series, we obtained anatomical reduction and clearance of intraarticular incarcerated fragments (as confirmed by postoperative CT scans) while treating acetabular fractures through a Kocher Langenbeck approach with the assistance of a large AO femoral distractor without the need for a specialized traction operative table.
The direction of the initial traumatic forces and the presence of an associated hip dislocation determines the acetabular fracture complexity and further affects fractured fragments size, comminution, displacement, and the presence or absence of marginal impaction at the articular surface of the acetabulum or the femoral head [
2,
10]. Furthermore, impaction injuries or incarcerated fragments could occur either during the injury incident or after the relocation of the hip joint [
30,
31].
In a study by Pascarella et al. [
30], the authors reported a retained intraarticular loose fragment in 45 patients out of a total of 127 patients presented with hip dislocation; the majority of the retained fragments occurred after a posterior dislocation reduction (43 out of 45 cases), the authors reported that they used two technique for removing these incarcerated fragments, either by traction through a pin inserted in the greater trochanter or dislocating the hip after manual traction applied by an assistant.
Regarding Impaction injuries associated with acetabular fractures, these could be either a dome impaction or a marginal impaction; if missed, they could lead to hip joint instability (especially if associated with posterior wall injuries) and fasten the development of post-traumatic hip osteoarthritis, so proper detection during preoperative planning and anatomical reduction of these injuries is paramount for obtaining optimum outcomes [
32‐
34]. The incidence of marginal impaction injuries associated with posterior wall fracture could reach up to 30% [
29]; furthermore, detached fragments could be incarcerated inside the hip joint and need retrieval [
32]. Several management options were described to treat such injuries, including surgical hip dislocation, posterior wall osteotomy, and hip arthroscopy; however, the previously mentioned options are considered technically demanding [
35‐
38].
In a study by Shaath et al. [
23], the authors reported their results of managing 172 acetabular fractures treated through a Kocher Langenbeck approach in a prone position over five years without using a specific traction table. They reported using the universal femoral distractor among the tools used to assist fracture manipulation and reduction; they reported no malreduction of more than 2 mm in any of the cases as measured on the postoperative CT scan. The authors reported that the universal femoral distractor was used in some cases; however, they did not report precisely the indications for its use or in how many cases they used it. Furthermore, they reported that in their series, they dealt with posterior wall or posterior wall-associated patterns of fractures; however, they did not report on the presence of impaction injuries or incarcerated fragments [
23]. In the current series, we decided preoperatively to use the femoral distractor after detecting either marginal impaction injuries or intraarticular incarcerated fragments as a part of preoperative planning.
We achieved hip joint clearance in all fractures associated with intraarticular incarcerated fragments, while anatomical fracture reduction was achieved in 77.8% of the cases. In a study by Giannoudis et al. [
29] presented their midterm results after managing marginal impaction injuries associated with acetabular fracture. The authors reported operating while the patient was prone on a radiolucent traction table, and to obtain hip joint traction, they often used skeletal traction by a pin attached to the distal femur [
29,
39]. In their series, they reported an initial anatomical reduction in 44 (73.3%) patients; however, the reduction was lost in 17 patients, leading to a final anatomical reduction of 45% [
29]; indicating the challenges surgeons face when dealing with such injuries, and the need for optimum operating conditions.
Although, in the current series, we reported operating on patients in a prone position, the femoral distractor could easily be applied if the patient was in a lateral decubitus position, as reported by Calafi and Routt [
18], which is attributed to the accessibility of the anatomical landmarks if the patient was in a lateral decubitus position where the two Schanz pins could be applied.
Furthermore, we reported that we used the femoral distractor in a total of 55 (13.1%) patients; in about half of those (25 patients), the indication for its use was either the presence of an intraarticular incarcerated fragment or a marginal impaction injury. However, in the remaining 30 patients, the indications were different, including assisting in the reduction of locked irreducible hip joint, in old cases where adhesions prevent appropriate fracture reduction, and in cases where the patient had a concomitant lower limb soft tissues or bony injuries where manual traction through the whole limb was not possible.
We believe that using the large femoral distractor in selected acetabular fracture cases has some advantages: First, the surgery can be performed on an ordinary fracture operative table (which is available in most institutions) without the need for a special traction table, which, if used could lead to some complications such as pudendal nerve palsy, erectile dysfunction, and perineal soft tissue injury [
40,
41].
Second, some surgeons manually perform hip joint distraction or insert a lateral traction pin through the femoral neck, which is also practiced in our unit [
42]. This could lead to a relatively inconsistent joint distraction and undue traction of the whole patient from the operative Table [
18]. Nevertheless, constant and stable traction is preferred when dealing with complex and unstable fracture patterns, which could be applied, adjusted, and maintained using the femoral distractor.
Third, draping and preparation of the whole limb are unnecessary as the distractor applies the traction through the surgical field; therefore, this technique is helpful if the patient has a concomitant ipsilateral lower extremity soft tissue or bony injury.
Fourth, the distractor gives adequate exposure to the hip joint upon surgical manipulation and will not obstruct the view of the hip during intra-operative imaging [
43]. Furthermore, as the distractor threaded spindle is attached by two arms to the Schanz screws barrels, it actually offsets the surgical field, and the surgeon could move the whole distractor away from the surgical field by applying longer Schanz pins. We did not encounter obscured visualization in the current series while the distractor was in place.
Fifth, in specific injuries such as marginal impaction, enough and maintained distraction enables the surgeon to visualize and reduce the impacted fragment and bone grafting. Furthermore, if an associated column fracture and the distractor caused displacement or obscure the column fracture reduction, the surgeon can undo the distraction until securing the column fracture and then reapply the distraction if needed.
Last, this technique does not need much of a learning curve and is practiced by most orthopedic trauma surgeons, unlike other surgical approaches used for managing impaction injuries, such as surgical hip dislocation, besides the availability of the distractor in most trauma surgery units [
19,
44,
45].
This study has some limitations; first, the small sample size could be attributed to the high selectivity of the included patients and those excluded due to inadequate documents. Second, the retrospective and non-comparative nature of the study could not enable us to compare other techniques used for managing such fractures. Third, we did not report the amount of distraction performed in each case; however, this issue was extensively reported in hip arthroscopy literature. Fourth, although we did not face such issues, using a femoral distractor might be unsuitable in patients with osteoporotic bone or with metal hardware around the hip. Lastly, we should have reported on functional outcomes at each follow up visit for all patients or the long-term sequel of managing these cases.
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