Isolated dislocation of the hip

K. PAPAGEORGIOU, I. GAITATGIS, A. HATZIOANNIDIS, K. VRADELIS
Department of Orthopaedic Surgery, General Hospital of Drama

ABSTRACT
Our study concerns patients with hip dislocation, who were treated conservatively. During the period 1980-2001 we have treated 20 patients with traumatic hip dislocation, aged 17 to 60 (mean age of 33 years), in whom men, with right sided posterior dislocation predominate and main cause was traffic road accident. 11 out of 20 patients had associated injuries and the majority of dislocations were reduced within the first 24 hours. Simple dislocations -according to Stewart-Milford classification- were predominated and 2 patients had paresis of sciatic nerve. After reduction of hip dislocation skeletal traction and thereafter physiotherapy was applied, as well as avoidance of loading, according of the type and concomitant injuries. Al the patients were reexamined 1 to 20 years (mean 8,85), after injury. By using pain, range of motion and return to work as criteria, results were satisfactory in the majority of the patients. A radiologic control (classical x-ray diagnostic picture) revealed heterotopic ossification in 3 out of 20 patients and osteoarthitic changes in 6, sans any clinical symptoms. Our observations and a review of literature show that simple hip dislocations had better functional recovery. Good results are obtained by early, accurate and stable reduction of dislocation. Associated injuries and late complications as avascular necrosis of the femoral head and osteoarthritis are severe with unfavourable prognosis.
Κey words: Hip, Dislocation, Conservative treatment.

INTRODUCTION
The hip is defined as stable joint, thus strong violence is demanded for the dislocation to occur. Associated injuries exist in 35 to 95% and include cranio-cerbral, chest, abdomen and musculo-skeletal injuries. Besides there may also be fractures in femoral head and the acetabular and in the adjacent area, without excluding the possibility that a fracture may exist in the long bone of the co ordinate and corresponding leg[8,24,25].
The Fracture-Dislocation of the hip was described by sir Aslley Cooper in 1791[18].The dislocation is more likely to occur to young motorcyclist and casualties from accidents with private cars (Dashboard injury). The direction of the dislocation depends on the position of the hip, the direction of the forces and also anatomy. The anterior dislocation are caused by forces with the leg in abduction and an lateral rotation and they cover 10-18%, of the total, while the posterior are caused by forces applied with the leg in (Flexion of the Knee-Hip) adduction and internal rotation. A fracture of the femoral head occurs 22-77% of the anterior dislocation and 10% of the posterior[5,10,25]. There are not many studies covering a long period of follow -up after a isolated dislocation of the hip and generally their prognosis is good[6,11,13,18].
Prognosis for these injuries depends on the time intervening between the injury and the dislocation, the accompanying injuries and the treatment after the dislocation[13,25].
Our aim is to present a retrospective study of conservative treatment of isolated (Simple) dislocation of the hip, with a long period of follow -up in relation to prognostic factors.

1.
Picture 1. Anteroposterior radiograph of the pelvis. Posterior dislocation right hip in man of 21 years, after road accident. The patient did not have accompanying injury, neuro-vascular injury and dislocation occurs at the collision in the dashboard of the car.

2.
3.
Pictures 2, 3. Anteroposterior radiograph of the pelvis, in neutral position and abduction, after reduction that became under general anaesthesia, 6 hours from injury. The hip they are clinical and radiological stable. It was applied skeletal traction for 4/52 and won weight-Bearing for one month.

MATERIAL-METHOD
20 patients with this injury were treated during the years 1980-2001, all aged 17-60 years (average 33yrs), predominating males (14/20) and right -side location of the injury (table 1). The main cause of the injury was the toad accident (18/20) and accompanying injuries were found in 11 patients, mostly fractures in the co-ordinate side (5 fractures in short bones and 1 with a fracture in long bone) (table 2). Posterior dislocation predominated (16/20) and patients with simple dislocation were selected: Type I: 16, and Type II: 4 with a fracture posterior wall of the acetabulum san displacement, according to Stewart-Milford[23], Thompson-Epstein[26] classifications (table 3)[25] and with a confirmed clinical and radiological stability. In all the cases reduction was made under general intube anaesthesia through Allis method and was successful at first attempt in 17 cases, at second in 2 and rather laborious in one case. In all the cases the clinical stability was checked (Rotation) with the hip in flexion. Apart from the usual radiological examination in 9/10, there was also an computed tomography, to confirm concentric reduction[4,25]. As regard to time the dislocation was reduction within the first six hours in 16 cases, within 6 to 12 hours in 3 cases and in 1 case it was reduction otherwise. Sceletal traction was applied to all the patients from tibial tubercle for 3/52 with both active and passive motion of the suffering hip.
Mobilization followed with non weight Bearing for a month and partial weight-Bearing for 3/52. Complete loading was permissible 10-12/52 after the injury. Early complications appeared in 2 patients with a posterior dislocations, a male with paralysis of the ischiatic nerve who recovered after 14/52 and a female with an extensive rupture -haematoma in glouteal area that was treated successfully.

4.
5.
Pictures 4, 5. Anteroposterior radiograph of the pelvis, in neutral position and abduction, 19 years after injury. The patient in asymptomatic and radiological does not exist osteoarthric changes. In outside of the neck observed osseous hyperplasia, propably from draw and separation of the articular capsule.

6.
Picture 6. Anteroposterior radiograph of the pelvis. Anterior dislocation right hip of Type I, in man of 35 years, after road accident, without neuro-vascular damage. The patient had pneumonothorax with fractures of the ribs and fracture of the mandible.

7.
Picture 7. Anteroposterior radiograph of the pelvis, that became under general anaesthesia, 6 hours from injury. The right hip they are clinical and radiological stability. It was applied skeletal traction for 4/52, non weigh-Bearing for one month.

8.
9.
Pictures 8, 9. Anteroposterior radiograph of pelvis, in neutral position and in abduction, 3 years after injury. The patient is asymptomatic and radiological is not observed osteoathritic changes.

 

RESULTS
All patients had both a clinical and radiological re-examination 2-20 years (average 8,85), while 8/20 patients had a period follow-up longer than 10 years. For clinical evaluation we used the Epstein clinical criteria7, that classify results as follow:
- Excellent: There is no pain, full range of hip motion. No roentgenographic evidence of progressive changes.
- Good: No pain, free motion 75% of normal hip motion. No more than a slight limp, minimum roentgenographic changes.
- Fair: Any one or more of the following: pain, but no disabling, limited motion of the hip, no adduction deformity. Moderate limp, moderately severe roentgenographic changes.
- Poor: Any one or more of the following: disabling pain, marked limitation of motion or adduction deformity. Redislocation, progressive roentgenographic changes.
Based on these criteria the result was excellent in 12 good in 7 and fair in 1 (table 2) (pictures 1-9). Furthermore, based on subjective criteria (How the patients themselves felt, their efficiency), the result was on the whole satisfactory and most of them returned to their previous occupations.
The pain was mild in 7 cases without need for medicine and in 1 case mild occasional need for analgesic. Stiffness was found I 7 patients without any serious functional implications (over 75% movement). Incipient changes of post traumatic arthritis were found in x-Ray examinations of 5 patients and medium gravity ones were found in 1 patient.
There seems to be lack of correspondence between clinical and radiological finds (Patients with osteoarthritis changes do not have symptoms). The small number of patients does not allow us to conclude whether and to what point this is statistically important. As for late complications, 3 patients had ectopic ossification Type I according to Brooker[2], without any essential functional implications on the hip. Avascular necrosis of the femoral head was not observed to any of the patients.

DISCUSSION
Traumatic dislocation of the hip used to be rare formerly and was mainly caused by fall from a horse. As time has passed its epidemiological and statistical data have changed. In recent decades there has been an increase in the frequency of occurrence due to road accidents (High energy road accident). The most frequent mechanism causing it, is hit of the bent Knee on the dashboard (Dashboard injury), especially when safety belt are not fastened. In a percentage from 62-93% in recent series the cause is high energy road accident[13,25,28]. In our series a road accident was the cause for 18/20 cases (14 in a car and 4 on a motorcycle).
Associated injuries to this grave injury are the rule and range from 40-75%[21]. It appears that associated injuries have an unfavorable influence on the final result, especially these of the lower limbs6.
In our series, despite the small number of patients, from 9 patients without accompanying injuries 7 had an excellent result, while from 11 patients with associated injuries (in 5 of them there were fractures of the lower limbs and 3 an accompanying fracture posterior lip of the acetabulum) only 5 had an excellent result (tables 1,2).
We have to remind here that the main principles in treating dislocation of the hip are the following:
1. Careful, detailed examination of the patient for associated injuries (Multi-Trauma patients, unconscious patients, fractures of the ipsilateral leg).
2. Radiological study with simple x-ray and computer tomography for the control of concentric reduction and MRI if needed.
3. Immediate close reduction with checking of the clinical and radiological stability.
4. A final estimation of the congruity of articular surfaces and examination for associated fracture femoral head-acetabulum[7,10,11,13,15,20,25]. Besides avoidance of violent movement is mentioned and not more than two attempts of reduction there was a risk of causing subcapital fracture and posttraumatic arthritis[3].
Most authors agree that early (immediate) reduction is the most important element of the initial management that prevents late complications caused by insufficient blood flow of the femoral head. The first 12 hours are regarded as a critical time period, while from recent studies it is shown that there is no important statistic difference between 12 and 24 hours[28].
Although in our study with small number of patients no diachronic aggravation of the osteoarthritis was found during a long follow -up (Young patients without particularly serious associated injuries). In other studies it appears that secondary osteoarthritis increase with time and this is related to age and associated injuries[27]. The relatively easy reduction may indicate a wide rupture - detachment of the posterior articular capsule in posterior dislocations and this could lead to redislocation if immobilization is not safe and sufficient in time[17].
For a long period of studies and research prolonged immobilization and discharge was the usual practice, but recent studies have not proved destructive consequences from early mobilization with continuous passive motion and an early weight -Bearing depending on the type of dislocation, associated injuries, age and the quality of the bone[10,14,22]. Simple traumatic dislocation without fracture quickly reset has a good result 85 to 100%[13,16]. Yet there are studies in which, isolated dislocations oh the hip gave a bad result at percentage up to 30%, for posterior dislocations[6].
Avascular necrosis of the femoral head is one of the most serious complications and occurs from 1,7 up to 40%, percentage which increases when reduction is delayed. If reduction is made within the first 6 hours, avascular necrosis ranges from 2-10% (table 4)[25]. Postraumatic arthritis is the next mayor complication that occurs to a percentage 20% and may reach 70%,after an open reduction[23]. It is believed today that apart from other factors, arthritis result from injury of articular cartilage (Destruction of the chodrocytes) at the time of the dislocation[1,19,25].

CONCLUSIONS
Simple (Isolated) dislocations of the hip with clinical and radiological stability, without associated injuries to demand restoration have a good prognosis and usually satisfactory results.
Reduction the soonest possible and absence of associated injuries are regarded as factors of good prognosis.
Besides as results from recent studies, injury of the reticular cartilage at the time of the dislocation, might silently menace of provocation posttraumatic arthritis, so the doctor must keep this in mind and inform the patient property.

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Mailing address:
Dr Kosmas Papageorgiou
Consultant AΥ Department of Orthopaedic
Averof 5, 66100 Drama
Tel: 2521031563, Fax: 2521023382
E-mail: kosmasp@otenet.gr