Anterior hip dislocation with ipsilateral displaced fracture neck of femur treated by open reduction and internal fixation: case report and review of the literature

A hip dislocation is an orthopedic emergency that must be reduced as soon as possible and when the patient’s condition allows. The main peculiarity of the presented case is the associated ipsilateral neck femur fracture to the anterior–inferior dislocation of the hip and the successful clinical and radiological outcome 2 years after surgery.

A posterior dislocation of the hip associated with a fracture of the femoral head [11‐13] and neck [14‐16] is unusual, but not rare but that of an anterior dislocation of the hip with associated fracture of the femoral head [6, 17‐20] or neck [7, 14, 18, 21] much rarer still.

These injuries occur in the young active patient with 75% of cases aged <50 years and present a treatment dilemma for the surgeon [5]. A review of the literature does not provide a consensus on whether this specific injury should be treated by primary open reduction and osteosynthesis or primary hip arthroplasty [9]. Proponents of total hip arthroplasty regard it is a definitive procedure. Sadler and DiStefano reported an anterior dislocation of the hip with an ipsilateral basicervical fracture, which was reduced and fixed with a hip screw and plate. Unfortunately, their patient developed avascular necrosis, which was treated with pedicle grafting. McClelland et al. reported another case with dislocation of the obturator type with ipsilateral fractures of the femoral head and neck treated with a collarless press-fit bipolar prosthesis. Dümmer and Sanzana reported a similar case associated with subcapital fracture which was treated by an uncemented total hip arthroplasty [22]. Drummer et al. [14] treated two cases by uncemented total hip replacement, and Meller et al. [16] used an endoprosthesis to treat one case.

In contrast, many authors consider that for the young adult there is really only one treatment option which is an open reduction and internal fixation of the femoral neck fracture. Here the main goals are to preserve the femoral head, avoid osteonecrosis and avoid nonunion. Arthroplasty procedures are not ideal given the younger age and expected higher functional demands [23].

Open reduction and internal fixation are a viable option if performed within a time frame. It restores the natural bone stock, and should an arthroplasty be required subsequently for avascular necrosis or degenerative arthritis, future complications of implant loosening and revision arthroplasty are averted potentially [24].

In many cases, the radiological development of avascular necrosis may be compatible with normal activity. It takes several years before degenerative arthritis and hip pain necessitate a joint replacement. Anatomical reduction and union can help in simplifying any future arthroplasty [24]. Klasen and Binnendijk [15] treated two patients with by open reduction and internal fixation, among whom one patient had no sign of avascular necrosis at a follow-up of 8 years. Maini et al. [25] treated one patient with posterior hip dislocation and fracture of femoral neck by open reduction and internal fixation. Intraoperatively, they found no capsular attachment on the head–neck fragment. At follow-up of 2 years, despite having early changes of avascular necrosis the patient did well functionally. Primary arthroplasty is a good option for patients who are old and there is concern about nonunion; this and that of repeated surgeries potentially favor a definitive procedure at the first attempt.

There was no associated acetabulum fracture in this case. Forces acting on the femoral head of the femur put high pressure on the walls of the acetabulum, exceeding their strength, breaking them; this is a common association with hip dislocations. Finally, the absence of any other associated visceral injuries is also notable. The patient had an ipsilateral fracture clavicle and scapula. Due to high-energy trauma forces involved in producing hip dislocations, abdominal and thoracic visceral injuries, neurological or other musculoskeletal lesions can occur, but can be overshadowed by dominant hip symptoms. This emphasizes a need for a careful general examination of the patient in order accomplish a complete diagnosis.

The main complications after a hip dislocation are avascular necrosis of the femoral head leading in time to osteoarthritis. There can be heterotopic ossification around the joint and an injury of the sciatic nerve. Avascular necrosis of the femoral head is thought to be multifactorial; on the one hand, during dislocation, the vascular network emerging from the trochanteric area is damaged with the joint capsule and is the round ligament artery with this ligament. Radulescu et al. [26] mentioned that Duncan and Shim [27] demonstrated a functional disruption of cephalic circulation by a spasm of the main artery or of the cervical branches, with no organic lesion itself. Thus, early reduction in the dislocated hip decreases the risk of avascular necrosis. A delay of more than 6 h increases the risk of avascular necrosis from 10 to 40% [26].

Sendtner et al. [28] stated that osteosynthesis with preservation of the head of femur is an emergency procedure that needs to be performed within 6 h. The pressure resulting from bleeding within the articular capsule will increase after this point in time. Manninger et al. [29] reviewed 494 cases retrospectively with fracture neck femur who were treated by open reduction and internal fixation and categorized the timing of surgery into three groups: those who were operated on in the first 6 h, between 6 and 24 h and after 24 h. There was a significant difference between the first group and the other groups in the incidence of nonunion and femoral head collapse with better results in the first group and with no difference in the incidence of complications between the second and third groups.

In this patient, although there was no preserved soft tissue attachment to the femoral head, the decision for ORIF rather than primary arthroplasty was taken due to the patient’s age and occupation. Follow-up X-rays did show a narrowing of the joint space suggestive of chondrolysis together with some calcification around the insertion of the gluteal abductors. Despite this, pain was mild on long distance walking and there was no limitation in range of motion. The main postoperative complication was a limp due to abductor action and thigh muscle atrophy because of delayed weight-bearing and missed active range of motion exercises. This was much improved with physiotherapy.