BILATERAL PATHOLOGICAL HIP DISLOCATION IN CHILDREN

Введение. Патологический вывих бедра является одним из наиболее тяжелых осложнений острого гематогенного остеомиелита. Программа лечения детей с патологическим вывихом бедра трудна, но достаточно разработана и весьма успешно реализуется. Вместе с тем, в доступной литературе не нашли отражения вопросы лечения детей с двусторонними патологическими вывихами бедер после перенесенного гематогенного остеомиелита, отсутствуют сведения об их частоте и отдаленных функциональных результатах. Материал и методы. Представлены результаты лечения 18 детей с двусторонними патологическими вывихами бедер после перенесенного гематогенного остеомиелита, что составило 23,1 % от общего количества больных (78), оперированных в 2000–2016 годах с диагнозом «патологический вывих бедра». У 12 пациентов оперированы оба тазобедренных сустава и у 6 — один. Для оценки анатомо-функционального состояния тазобедренных суставов использованы клинический и рентгенологический методы исследования. Результаты и обсуждение. С целью стабилизации и восстановления функции тазобедренных суставов 18 детям выполнены 30 оперативных вмешательств: простое открытое вправление бедра (19), а также открытое вправление бедра с артропластикой тазобедренного сустава одним (6) или двумя (5) деминерализованными костно-хрящевыми аллотрансплантатами. Решение о возможности выполнения оперативного вмешательства на втором тазобедренном суставе принимали только после контрольного осмотра ребенка и получения положительной информации об анатомическом и функциональном состоянии оперированного тазобедренного сустава. Поэтому 14 (77,8 %) детям оперативное лечение второго тазобедренного сустава было выполнено через 1–1,5 года после проведения курса консервативных мероприятий по восстановлению амплитуды движений в ранее оперированном тазобедренном суставе. В сроки от 1 года до 12 лет обследованы 17 пациентов, из которых 10 оперированы с обеих сторон (27 суставов). Отмечено сохранение до 80° и более амплитуды движений в 17 (62,9 %) из 27 оперированных тазобедренных суставов. Решая задачу помощи больным с патологическим вывихом бедра, необходимо осознавать, что реконструкция сустава с «доведением» его до анатомического состояния противоположного непораженного сустава практически невозможна. Что касается двустороннего поражения, то это невозможно вдвойне, и развитие артроза неизбежно. Поэтому наиболее важной составляющей, отражающей степень благополучия пораженного сустава, наряду со стабильностью, является амплитуда активных движений. Сохранение ее на фоне бережного и внимательного отношения к пораженным суставам является основополагающей и решаемой задачей.


Introduction
Pathologic dislocation of the hip is one of the most severe complications of acute hematogenous osteomyelitis.It has occurred in children of early age and manifests not only as a disorder of anatomic arrangements in the aff ected hip joint but also as destructive changes in the femoral head and neck of various degrees.Th e disorder of cotyloidcavity growth and scar changes in the soft tissues surrounding the joint contribute to the formation of joint contractures and the development of secondary static deformities.
Treatment of children with pathologic dislocation of the hip is diffi cult, but it has been suffi ciently developed and can be implemented very successfully [1][2][3][4][5][6][7].At the same time, to our knowledge there have been no reports of treating children with bilateral pathologic dislocations of the hips after hematogenous osteomyelitis.Th ere is no information on their frequency and long-term functional results.Only single publications have addressed the issues of diagnosis and treatment of bilateral hip dislocations in children with a history of infl ammatory processes [8,9].In the literature on pathologic dislocation of the hip, data have indicated that two-sided localization is fairly rare [1].

Material and methods
From 2000 to 2016, we supervised 18 patients (11 boys and 7 girls aged 1.5-9 years) with bilateral pathologic dislocations of the hips caused by acute hematogenous osteomyelitis during the neonatal period.Th ese patients constituted 23.1% of the total number of patients (78) who underwent surgery in the department of bone pathology of the Turner Scientific and Research Institute for Children's Orthopedics, the Ministry of Health of Russia, during the specifi ed period with a diagnosis of pathologic dislocation of the hip.Clinical and roentgenologic studies were performed to assess the anatomic and functional state of the hip joints.Standard (prone) and functional (upright) radiographs of the hip joints were performed to assess the degree of stability.
All patients were examined after voluntary consent from their parents or offi cial representatives was obtained.

Results and discussion
According to the x-ray data, most patients had no full femoral head and neck, and their proximal ends were represented by greater trochanters or the latter in combination with the remnants of the heads and necks (23 joints, 63.9%; Fig. 1).In addition to the hip joints, 10 (45.5%) children suff ered from lesions of other joints, including the knee (4), humerus (2), and the maxillomandibular joints (4).Of the 18 children, 12 (9 boys and 3 girls) underwent surgery of both hip joints, whereas one hip joint was operated in 6 patients.Unilateral surgical intervention was performed once in four children, while two required additional surgeries to stabilize (1) or restore the function (1) of the joint.
Th e surgical intervention was performed in 14 (77.8%)children between the ages of 1.5 and 4 years and in 4 (22.2%) at the age of 5 years or older.Th e decision on the possibility of performing surgery on the second hip joint was made only aft er follow-up examination of a child was performed and positive information was obtained about the anatomic and functional state of the operated hip joint.Th erefore, 14 (77.8%)children underwent surgical treatment of the second hip joint 1-1.5 years aft er the course of conservative measures aimed at restoring the amplitude of movements in the previously operated hip joint.A positive surgical result was determined when there was absence of dislocation at a suffi cient degree of osseous covering of the proximal end of the thigh bone by the acetabular roof and when the fl exion amplitude in the operated hip joint exceeded 60º (Fig. 2).
To stabilize and restore the function of the hip joints, 18 children underwent 30 surgeries: simple open hip reduction (19) and also hip reduction with hip joint arthroplasty with one (6) or two (5) demineralized osteochondral allografts (DOCA).These procedures were done for single-step (15) or sequential (3) formation of the acetabular roof (7), modeling resection of the proximal end of the thigh bone (8), or corrective, including shortening, osteotomy of the thigh bone (5).One patient who had pronounced changes in one of the aff ected hip joints underwent the maximum amount of surgical interventions for stabilization, including open hip reduction, hip joint arthroplasty with two DOCAs combined with detorsion and shortening osteotomy of the thigh bone, and a Salter procedure.
Surgery was performed with the patient lying on a healthy side.Aft er the arcuate Watson-Jones incision was made and dissection of the superfi cial and fascia lata of the thigh was performed, the great trochanter was cut off, together with the ventral gluteal muscle and gluteus minimus muscle attached to it.Th e scar cords in these muscles were intersected with a pointed scalpel-tenotome without transsection of the muscle fibers.The proximal end of the thigh bone and the cotyloid cavity were isolated and released from the scar tissue, and the lumboiliac muscle was transsected.Th e proximal end of the thigh bone was assessed visually, and if the head of the femoral bone was preserved, its articular cartilage as well as the cartilage of the cotyloid cavity were assessed.In the absence of destructive changes in the cartilage of the femoral head and the cotyloid cavity, the proximal end of the thigh bone was immersed in the cotyloid cavity at the abduction position (30°-40°) and the internal rotation of the thigh (10°-15°), and the greater trochanter was fixed to the outer surface of the thigh bone with a screw or pins 1-1.5 cm below its previous position.Th e postoperative wound was closed layer-by-layer with drainage tubes placed.Tenotomy was performed for the tension of the adductor muscles of the thigh.At weeks 3-4, a sesquialteral coxofemoral plaster cast-spacer was applied.
In the absence of the femoral head or destruction of the hyaline cartilage of the femoral head, the surface of the proximal end of the thigh bone was formed with the help of ball-shaped mills.In the case of destruction of the hyaline cartilage of the cotyloid cavity, its spherical surface also was formed with the milling cutter.In younger children, sparing treatment of the cotyloid cavity should be performed to avoid its bottom's protrusion.After treatment of the thigh bone and the cotyloid cavity, on the shaped surfaces, for the various indications, one or two whole or perforated DOCAs were fi xed along the periphery with separate or twisted sutures.Th e proximal end of the thigh bone was immersed in the cotyloid cavity in the above position, and the incised great trochanter was fi xed to the outer surface of the thigh bone with a screw or pins 1-1.5 cm below its previous position.The postoperative wound was closed, and at weeks 3-4, a sesquialteral coxofemoral plaster cast-spacer was applied.
An important component of the success of surgical intervention is decompression of the hip joint, which is provided by free insertion of the proximal end of the thigh bone into the prepared cotyloid cavity.Therefore, in children with a preserved femoral head and neck, before their insertion into the cotyloid cavity, according to the indications, a shortening osteotomy of the thigh bone was performed from a separate access in the lower or middle third, which, with the great trochanter incised, preserves the viability of the femoral head and neck.
It should be noted that with the relative stability of the hip joint and the retention of the proximal end of the thigh bone within the cotyloid cavity, surgery may be limited to the aforementioned aids.Additional (if necessary) stabilizing extra-articular intervention in the form of transposition of the cotyloid cavity or acetabuloplasty (pelvic osteotomy) can be performed at the second stage aft er restoring the amplitude of movements in the operated hip joint.
In case of pronounced hip joint instability due to slanting of the arch and fl attening of the bottom of the cotyloid cavity, the extent of surgery can be increased.In this case, open thigh reduction or arthroplasty of the hip joint with DOCA can be supplemented by transposition of the cotyloid cavity (pelvic osteotomy), and the period of immobilization with a plaster cast is increased to 5-6 weeks.
The restorative measures were begun at the moment the plaster cast was transferred to the plaster "bed" and on X-ray examination of the condition of the operated hip joint.Th e plaster "bed" 3 weeks aft er removal of the plaster cast in older children was left only for the night.In younger patients, it is advisable to leave the plaster "bed" for a longer period.During the day, a child would receive exercise therapy (ET) with the help of an instructor or with parents, who had been trained for the elementary skills of the ET.Depending on the age of the child, ET was performed up to three times a day with 40 min between physical therapy sessions.Cuff stretching was prescribed for the child for the thigh or lower leg with loads of 1.5-3 kg, which can be performed directly in the ward.Cuff stretching was not prescribed for children younger than 5 years since, with suffi cient decompression of the hip joint, the restoration of movements was achieved with the help of physical therapy exercises.To prevent formation of rotary contractures, the limb was fixed in the middle position using a removable derotation plaster "boot" with its obligatory retraction in the hip joint.To restore movements in the operated hip joint, the child was allowed to sit down in bed for short periods of time.
Four weeks aft er the removal of the plaster cast, the plaster "bed" was discontinued in the older children.At the same time, the child was advised to continue to observe the regimen of periodic cuff stretching.At this time, active movements were prescribed in the joints of the operated limb with gradually increasing amplitude.
At 3-4 months after surgery, the child was allowed to ride a bicycle and walk with crutches without leaning on the operative lower limb.Th e list of physical therapy exercises to prevent fl exion contracture included a setup for hip extension, the performance of which was obligatory aft er each ET exercise.
At 5-6 postoperative months, the child was allowed graduated weightbearing on the forefoot.The load on the limb was increased gradually by month 8 after the end of the postoperative period, and full weightbearing was allowed 10-12 postoperative months after evaluation of the radiographs of the hip joints.
It should be noted that all children were discharged from the hospital after a control Pediatric Traumatology, Orthopaedics and Reconstructive Surgery.Volume 5. Issue 1. 2017 X-ray examination and a course of conservative therapy, including massage, physiotherapy, and ET, with an amplitude of fl exion in the operated hip joint of at least 80°-90º, if they had retained this amplitude at follow-up aft er 3 to 4 months.Th is time interval seemed to be suffi cient for assessing the functional state of the operated joint and was used for hospitalization of a child in an inpatient department for removal of metal structures.
All patients suff ered from lameness, which is caused not only by the dislocation of the thigh bones but also by the shortening and weakness of the gluteal muscles.Pain syndrome was not noted in any observation.
The marked lordosis of the lumbar spine due to the presence of moderately pronounced adduction-flexion contractures of the hip joints was seen in five patients.In this context, the amplitude of movements in 17 (62.9%) of the 27 operated hip joints exceeded 80° to 90º, and in 9 (33.3%)joints it reached 100º or more (Table 1).These amplitudes of movements in the operated hip joints, depending on the type of surgical intervention performed, among which open hip reduction predominated (66.7%), are of interest.At the same time, the results of the examination indicated preservation of the amplitude of movements in the joints, exceeding 80°-90º and even 100º or more in the long-term follow-up period in the majority (62.9%) of the patients.Attention should be paid again to the functional results of treatment of children who underwent arthroplasty with the use of a DOCA for the purpose of stabilizing the hip joint.In our study, as in a study conducted previously [10], the frequency of positive long-term results is very high.As for ankylosis and expressed extension contractures, their number is insignifi cant and did not exceed 15% (Table 2).Th e attitude toward treatment of bilateral hip dislocations remains ambiguous, and "it is much more diffi cult to decide the reasonability of the surgery" [11], especially since the long-term functional results of treatment are far from perfect [11,12].Th erefore, considering the results of treatment of children with bilateral congenital dislocations of the hips, many investigators reasonably note that it is advisable to operate on the second hip joint only when surgical intervention on the fi rst joint was successful and function was restored [11,13].We fully share this position.
To solve the problem of helping patients with pathologic hip dislocation, it is necessary to realize that remodeling of the joint by "bringing it" to the anatomic state of the opposite unaff ected joint is practically impossible.In the case of bilateral lesions this is especially impossible and the development of arthrosis is inevitable.Th erefore, the most important component, refl ecting the degree of well-being of the aff ected joint along with stability, is the amplitude of active movements.Preserving this amplitude, while keeping a careful and attentive attitude towards the aff ected joints, is a fundamental and solvable task and it is quite realistic.

Information on funding and conflict of interest
Th is work was performed on the basis and with the support of the Turner Scientifi c and Research Institute for Children's Orthopedics, the Ministry of Health of Russia.Th e authors declare the absence of obvious and potential confl icts of interest related to the publication of this article.

Fig. 3 .
Fig. 3. Radiographs of the hip joints and photographs of patient K., 4 years old, with pathologic dislocations of the hips before (a) and 1 year aft er the stabilization of the hip joints (b, c, d)

Table 1
Amplitude of movements in the operated hip joints at long-term follow-up

Table 2
The amplitude of movements in the operated hip joints at long-term follow-up period, depending on the type of surgical intervention performed OR -open hip reduction; MR -modeling resection, including subchondral modeling of the femoral head; CO -corrective shortening osteotomy of the thigh bone; and A -arthroplasty of the hip joint. Note: