Traumatic dislocations of the hip in children About 11 cases and literature review

Prior to surgery, information was obtained on the following: (a) patient age and gender; (b) type of dislocation; (c) type of trauma; (d) time from dislocation to reduction; (e) type of treatment; (f) duration of immobilization; (g) associated injuries; and (h) complications. The clinical assessment focused on symptoms and physical examination fi ndings. The clinical data and all radiological examinations were analyzed and the dislocations were divided into two categories: anterior and posterior. The posterior group was subdivided into fi ve groups according to Thompson and Epstein [6] (Table 1). Particular attention was paid to the evaluation of heterotopic ossifi cation, avascular necrosis and epiphysis hypertrophy (coxa magna 2mm to the opposite side). Abstract


Reduction method
For each patient, we used one of the three reduction methods, as detailed below.
Technique 1: Technique 1 (T1): Is applied to any patient who has an interval of 3 weeks or less between trauma and reduction. Urgent closed reduction for trauma Hip dislocation is indicated for dislocation with or without neurological defi cit in the absence of an associated fracture (Figures 1,2). If the hip fails to reduce after two or three attempts at a closed reduction, an open reduction must be performed.      7) is used to avoid further devascularization of the femoral head and special attention is given to visualization and protection of the sciatic nerve. The hip capsule is exposed to identify the articular cartilage of the femoral head, the round ligament and the acetabular cavity. Parts of the very thick antero-inferior capsule are removed and the psoas insertions are detached. If the acetabular cavity appears to be very shallow, the acetabulum is cleaned of all scar tissue with a sharp spoon. The femoral head is reduced in the acetabulum by traction and countertraction. The capsule is joined at the bottom and left open for drainage [8].
A 3 mm Kirschner wire is inserted through the femoral head into the acetabulum. A capsuloraphysis with non-resorbable sutures. Patients are immobilized in a pelvic-pedestrian cast immediately.

Patient follow-up
The pin removal was done at 3-4 weeks. The time of hip cast removal varies: for patients who underwent reduction according to T1, it was done in 3 weeks; for T2 in 6 weeks; and for T3 in 9 weeks. After removal of the cast, X-rays of the hip were taken for all patients. After cast removal, each patient underwent a period of protection (sports abstention and crutching): for patients with T2 reduction, it was 6 months; and for T3, it was 9 months. Patients were independently assessed every 6 months thereafter.
After reduction, each patient's medical records were reviewed, focusing on symptoms, physical fi ndings, and x-rays of the hip. Clinical assessment focused on range of motion, presence of pain and/or lameness, and ability to squat. A Harris hip score [5] was also calculated for each patient at 6 months after dislocation and at fi nal follow-up.

Results
From January 2010 to January 2019, 11 patients (11 hips) were treated for traumatic hip dislocation. Of the 11 in our study, 06 (54.5%) occurred on the right side and 05 (45.5%) on the left side. Eight (72.7%) were male and three (27.3%) were female. Age at diagnosis ranged from 3 years, 2 months to 9 years, 10 months. There were two age groups in which hip dislocation appeared to be more common, with 08 of the 11 patients (72.7%) between 3 and 6 years of age, and 3 of the 11 patients (27.3%) between 7 and 10 years of age. All patients had Thompson and Epstein type I posterior dislocations [6] with no associated fractures. hours-3 weeks in 1 patient)]; 3-6 weeks in 1 patient (4 weeks in 1 patient); and more than 6 weeks in 1 patient (9 weeks in 1 patient).8 patients underwent reduction according to T1; 2 patients underwent reduction according to V2; and 1 patient underwent reduction according to V3 (Table 2).
We had excellent results in four hips (36.4%), good results in three hips (36.4%), satisfactory results in three hips (18.2%), and poor results in one hip (9.1%).

Discussion
Traumatic dislocation of the hip is rare in children and can occur as a result of minor injuries sustained while playing or participating in sports activities. Barquet [9], Hamilton and Broughton [2] and Rieger, et al. [11], also found that the magnitude of the force producing the injury increased with the age of the patients. We believe that low-energy trauma can cause dislocation in younger patients because their periarticular structures are more fl exible. The fl exibility of the periarticular structures may also explain the absence of bone damage to the acetabulum or femoral head, unlike adults, in whom acetabular fracture is a common problem. However, all patients with traumatic hip dislocation and even patients who have been involved in an accident should have a careful examination of the entire body to identify other associated injuries. Several authors [2,11,12] have classifi ed traumatic hip dislocations into two groups according to age and time of injury. The fi rst group included children under 10 years of age, admitted following a relatively minor trauma, such as a simple fall. Barquet [13] and Schlonsky and Miller [14] also found that the magnitude of the forces involved in the injury increased with the age of the patient. As Mehlman,et al. (15) point out, the interval between dislocation and reduction should be as short as possible to limit the risk of necrosis. The risk of necrosis is 3-15% [13,15,16].
Although opinions on treatment differ, it is agreed that rapid reduction of hip dislocation is the most important initial treatment [17]. Full recovery can only be achieved after early reduction; a critical delay has been reported by some authors up to 12 h [17]. More recent articles recommend a reduction within 6 h [10,18], but none of these studies have included a suffi cient number of patients who underwent hip reduction between 7 and 12 h. Yang, et al. [19]. found no statistical difference between one under 12 and one between 12 and 24 hours. Among our patients, two patients (13.6%) had avascular necrosis and in both cases there was a delay in treatment of more than 4 weeks (Figure 8).
Although a number of treatment methods have been reported, the best strategy for this problem is not yet in place.

Conclusion
Children with a traumatic hip dislocation should have their hips reduced as soon as possible. All patients with a traumatic hip dislocation should have a thorough whole-body examination to identify other injuries. The factors that seem to have the greatest infl uence on the fi nal outcome are as follows: 1) The time interval between injury and reduction 2) Beyond 3 weeks, a reductive operation should be performed; we suggest surgical technique 2. This simple and safe method leads to a marked improvement in hip function and prevents the occurrence of complications.
3) Adherence to the principles of immobilization and management after reduction of the dislocation: the shape and duration of the pelvic-pedestrian cast, bonded traction, removal of the pin, protection period, and clinical-radiological control.