Femoral head fracture is a rare injury to the hip, accounting for approximately 4%–17% of the cases of traumatic hip dislocation cases (1). Only 1.25% of all hip dislocations are simultaneous bilateral (2, 3). Dislocations and fractures require significant forces, which are typically encountered in high-velocity motor vehicle accidents. The majority of them are either unrestrained drivers or front-seat passengers. Birkett described the first femoral head fracture followed by posterior hip dislocation in 1869 (4), whereas Garrett Pipkin classified the fracture pattern in 1957 based on the location of the head fracture in relation to the fovea and the associated lesion on the femoral head or acetabulum (5). Meislin and Zuckerman were the first to report the symmetrical bilateral Pipkin fracture type IV which was treated with cemented hip arthroplasties (6).

In this paper, we report a rare case of symmetrical bilateral hip dislocation with femoral head fracture (Pipkin II) treated surgically using a direct anterior approach (DAA), with a successful outcome after a 5-year follow-up.

A 46-year-old woman presented with a history of a car accident 1 day ago. She complained of severe hip pain and difficulty in thigh movement. The patient presented to our hospital after the primary treatment of hip joint reduction. Due to bilateral hip pain and limited movement, radiographic examinations were performed in the emergency department of the local hospital. The patient was diagnosed with “hip dislocation and femoral head fracture.” After 1 day of inpatient observation, the patient was transported to our hospital department. The patient had no previous medical history.

One month after the operation, the patient was advised to perform partial weight bearing with the help of a walker to get out of bed. Eight months after the operation, the patient walked normally with full weight bearing without limping and normal return to daily activity. Follow-ups in first and second years showed improved modified hip score 74 (fair) and 83 (good), respectively.

According to the D'Aubigne range of motion scale, the latest hip score in the fifth year was 86 (good). The patient had a full range of movement in both hips: flexion of 120°, internal rotation of 30°, external rotation of 50°, and abduction of extension of 40°. At five-year follow-up X-rays, there was no incidence of osteonecrosis, heterotopic ossification, or signs of post-traumatic arthritis (Figure 4). She resumed daily and normal activities without any disability after a severe tragic incident.

Bilateral posterior dislocation of the hip occurs in approximately 1.25% of all hip dislocations (3, 7). Of posterior dislocations, 5–15% are associated with femoral head fractures (8). High-velocity motor accidents are the main cause of dislocations associated with femoral head fractures. Management of these cases is rare and controversial, and few cases have been reported in the literature. Previous studies have focused on the initial close reduction and conservative treatment. Authors such as Guiral et al. (9), and Treacy and Grigoris (10), advocated conservative treatment with skeletal traction with satisfactory outcomes. Whereas Zuckerman 1989 performed the surgical treatment with bilateral cemented total hip replacement (6). Table 1 consists of a list of English language publications retrieved from PubMed, Embase, and Google Scholar databases for the oldest available case reports and abstracts from 1962 to 2022 for bilateral femoral head fractures (Pipkin fracture). Of these, only 10 were relevant after screening every article and case report, and one case report was excluded due to the unavailability of the abstract or an entire report.

Hip dislocation is an orthopedic emergency, and closed reduction must be performed within 6 h postinjury. The incidence of femoral head necrosis after fracture dislocation of the hip can be high, from 4.8% to 52.9%, depending on the time of reduction (18). Complications such as traumatic injuries to the sciatic nerve (mostly peroneal division), avascular necrosis of the femoral head (AVN), and post-traumatic osteoarthritis (PTOA) can occur after the incidence (19).

Only close reduction of this type of fracture pattern may also lead to AVN up to 5%–15% and may increase to 40%, requiring operative treatments (20). In our case, a closed reduction and conservative method for the larger fractured fragment on the inferior side could adversely influence the joint range of motion and stability. We also know that resection of the fragment in femoral fractures might not significantly affect the loading zone of the femoral head, but long-term consequences such as pain during mobilization and heavyweight bearing leading to arthritis as an outcome should always be considered. Therefore, we took the consideration for open reduction and anatomical internal fixation on bilateral hips.

Previously, it was considered that most internal fixation was performed using the posterior approach. The posterior approach has been associated with a greater rate of AVN than the anterior approach (21–23). Various operative approaches have been opted for Pipkin fractures depending on the femoral head fragment, the direction of the dislocation, and the associated acetabular fractures.

Several types of approaches are described in the literature: posterior (Kocher–Langenbeck), posterolateral (Moor), anterolateral (Watson Jones), trochanteric flip osteotomy, Gibson surgical hip dislocation, and direct anterior approach (Smith–Peterson) (24, 25). Our preference is for DAA, which is also interchangeably called modified Hunter’s anterior surgical approach or Smith–Peterson to treat bilateral Pipkin type II justifying the minimally invasive, adequate exposure for femoral head fixation, surgical positioning in the supine position, short hospital stays and rapid recovery of incision wounds. Our method's major assets are its least invasiveness, adequate femoral head exposure, reduced intraoperative blood loss, quicker surgery time, speedy wound healing, low visual analogue scale (VAS), and practical supine surgical position. The posterior medial femoral circumflex artery, which supplies the majority of the blood to the hip and is susceptible to damage during posterior hip dislocation, is likewise preserved by the direct anterior approach. It is interesting to note that DAA has been analyzed by a multiple researchers; the learning curve is smooth, mastery of the skills can be attained with the proper guidance, and implementation problems are rare (26). The limitation of this approach can be a contradiction in high Body Mass Index (BMI) patients. Intraoperatively, damage to the lateral femoral cutaneous nerve occurs as it passes subcutaneously between the Sartorius and TFL (26, 27).

However, this approach was related to a higher rate of heterotopic ossification (HO) (28–30). According to certain studies, HO is more common in men and elderly patients, as well as those who had primary osteoarthritis, a high body mass index, a low preoperative range of motion, and longer operations (31). We thought that low disruption of the soft tissue due to less invasive surgery, such as DAA, can lead to less local tissue damage and inflammation, especially tenotomy of the gluteus fibers and hip capsule, which may contribute to the low incidence of HO. Furthermore, pharmacological prophylaxis with selective or nonselective Nonsteroidal anti-inflammatory drugs (NSAIDs) can be used to treat HO by preventing bone formation by preventing inflammation and decreasing the osteogenic differentiation of progenitor cells (31).

Pipkin fracture is accompanied by complications such as avascular necrosis, secondary arthritis, peripheral nerve damage, and heterotrophic ossification. Nevertheless, PTOA is a long-term complication and degeneration process of the hip that can manifest as pain, decreased range of motion, and change in gait. The prevalence of PTOA following traumatic hip injury is higher in the elderly, in hip fractures with posterior acetabulum fractures, and in prolonged traumatic dislocations. Femoral head subchondral impaction or chondral injury during traumatic dislocation increases the risk of end-stage osteoarthritis leading to Total Hip Arthroplasty (THA) by 3.68 times (32). PTOA can be caused by femoral head cartilage lesions or osteochondral fragments in the joint, in addition to the quality of anatomical reduction during osteosynthesis. Even if the joint appears severely damaged on radiography, PTOA can remain silent for a long time and not manifest itself. As a result, long-term clinical monitoring and radiography are required. The radiographs of the patient was checked for signs of avascular necrosis, early sclerosis, and arthritic alterations. The clinical evaluation and radiographic assessment were correlated at the 12th week, 1-, 2-, and 5-year follow-ups.

Recently, we found many other materials, such as bioabsorbable screws, biodegradable polylactide pins, and osteochondral autografts, for the treatment of femoral head defects. Regardless, Herbert or cancellous screws are used abundantly (33). Herbert screws have the advantages of a good fixation strength and biocompatibility. It prevents the screw from protruding into the joint and has less rejection reaction that aids the fragment to part together for bone healing (34).

In summary, bilateral Pipkin fractures are rare. The key lesson to be learned from this case report is the need for immediate reduction of a dislocated hip, followed by open reduction and internal fixation using the minimally invasive direct anterior surgical technique for sufficient surgical access with a safe and effective method to treat HO, AVN, and PTOA after surgery.