Developmental Dysplasia of the Hip (DDH), formerly known as Congenital Dislocation of the Hip (CDH), is a general term for a group of pathologies characterized by spatial and temporal instability of the hip joint during development, including hip dislocation, subluxation and acetabular dysplasia. DDH can cause abnormal gait, abnormal development of adjacent joints, and secondary deformities of the spine in children, leading to lower back pain and pain caused by degenerative changes of the hip joint in adulthood. Because the disease is closely related to the developmental process of the hip joint, the presentation and corresponding treatment varies among age groups.
The aim of DDH treatment is to obtain a stable concentric reposition and avoid ischemic necrosis of the femoral head AVN,. Early diagnosis and early treatment are the keys to improve the outcome.
I. Birth ~ 6 months
This stage is the prime time for DDH treatment, with simple and easy method, good compliance, reliable efficacy and few complications.
1. Clinical manifestations and signs: asymmetry of thigh skin pattern and hip pattern, joint popping and unequal length of lower limbs. Positive hip abduction test on the dislocated side. Ortolani/Balow sign is positive. Inequality of limbs, positive Allis (Galleazzi) sign, etc.
2.Imaging: Ultrasound examination of hip joint is preferred for children ≤4 months old, Graf method; X-ray double hip orthopantomographs can be taken for children >4 months old, commonly used indicators are Perkin’s square, acetabular index (AI), central marginal angle (CEA), Shenton’s line, tear drop (Teradrop) sign.
3, Treatment: Pavlik sling is preferred to maintain hip flexion at 100° to 110° and abduction at 20° to 50°. 24 hours maintenance. Prohibit dislocation movements including examination and change of clothing,. Regular ultrasound examination, 1 time / 1 to 2 weeks . If ultrasound suggests obtaining concentric repositioning after 3 weeks, continue to maintain for 2 to 4 months. An abduction brace was then used until the acetabular index (AI) was <25° and the central marginal angle (CEA) was >20°. If ultrasound and clinical examination after 3 weeks suggest that no repositioning has been achieved, the Pavik sling is discontinued and other treatment is used instead. Otherwise, persistent compression of the posterior dislocated femoral head against the acetabular wall may result in sling disease with posterior acetabular wall dysplasia,. Other treatment methods include brace fixation in the same position as the sling, or direct closed cast fixation, avoiding repositioning under non-anesthesia, wearing extreme frog, and abduction brace to avoid damage to the femoral head cartilage and AVN.
II. 7 months to 18 months
With the increase of age, weight and activity increase, the compliance and efficacy of using sling decreases.
1.Clinical manifestations and signs: In addition to the above manifestations, physical examination shows asymmetrical appearance of both hips, wide perineum, high greater trochanter, telescope sign telescope sign,, and positive Allis sign.
2, treatment: the first choice is closed repositioning under anesthesia, human position plaster tube type fixation. Before closed repositioning, the internal longus muscle should be incised or cut percutaneously, and if necessary, the iliopsoas tendon should be cut at the same time, and repositioned by gentle Ortolani technique. The observation index is safe zone, >20°. Arthrography with Onyepek is recommended. If the angiogram shows a gap of >4 mm between the cartilage margin of the femoral head and the inner wall of the acetabulum, it suggests soft tissue impaction between the head and socket, which prevents repositioning. Abandon closed resurfacing and use the medial approach with Ludolff, Ferguson, or anterolateral approach with Bikini, S-P, and incisional resurfacing instead. Preoperative skin traction is possible for 1-2 weeks, or for several weeks to achieve repositioning. After repositioning, the hip is fixed in a human plaster cast in 100° of flexion, 40-50° of abduction, and neutral rotation for 3 months, and then the cast is replaced and continued to be fixed in a plaster cast or brace for 3-6 months.
At the end of the above treatment, the child has the following conditions: 1, concentric cephalic socket repositioning and observation; films are taken every 6 months; 2, cephalic socket repositioning but residual acetabular dysplasia, manifested by steep and straight acetabulum, AI>24°, but continuous Shenton line, wearing an abduction brace, especially at night; films are taken every 4 months to observe acetabular inclusion AI, CEA, improvement, or whether there is semi 3. Residual subluxation, manifested by discontinuity of the Shenton’s line, is usually associated with acetabular dysplasia. An abduction brace may be worn, and the patient should be reviewed every 3 months for a total of 6 to 12 months. The radiographs, especially the orthopantomogram of the pelvis under weight bearing in the standing position, if show persistent discontinuity of Shenton’s line, surgical correction; if it continues to improve, the treatment is the same as 2,; 4, residual AVN, the affected femoral head should be placed under the inclusion of the acetabulum to allow repair and shaping. The specific treatment is the same as 2, 3.
Third, 18 months to 8 years walking age
1, clinical manifestations and signs: limp, duck walk; unequal lower limbs, increased lumbar lordosis, restricted hip abduction, positive Allis sign, positive Trendelenburg sign, etc.
2.Imaging: X-ray double hip orthopantomographs, assessment indexes are the same as before. CT 3D reconstruction is an effective means to observe the anterior femoral tilt angle and posterior dislocation.
3.Treatment: It is still possible to try closed repositioning within 2 years of age, but most children need incisional repositioning and osteotomy. Osteotomy of the pelvis and proximal femur not only corrects the deformity of the acetabulum and proximal femur itself, but also provides stability after reset.
Currently, there is a common international phase I surgical treatment; incisional repositioning, pelvic osteotomy, and proximal femoral osteotomy. Preoperative traction is not required.
1. Incisional repositioning: anterolateral S-P or Bikini approach. The main points are: full exposure, release, T-shaped incision of the joint capsule, removal of the acetabular contents of the round ligament, the transverse menhaden ligament, avoid excision of the menhaden lip, the femoral head is also incorporated into the true acetabulum to achieve a concentric compound
The head of the femur is also incorporated into the true acetabulum to achieve concentric repositioning, and the V-shaped capsule is tightened and shaped.
2, pelvic osteotomy style selection: any kind of pelvic osteotomy can not treat DDH, the basic preoperative requirement is that concentric repositioning has been achieved. Reconstructive pelvic osteotomy should be preferred, mainly: a change the acetabular direction: Salter, Triple Triple, osteotomy; b change the acetabular form: for large acetabulum and relatively small femoral head, steep and straight acetabulum, true and false acetabular continuation.
Commonly used is Pemberton osteotomy, Dega osteotomy.
3, proximal femur inter-rotor, sub-rotor and shortening osteotomy is to reduce the pressure between the head and socket to avoid AVN; rotational inversion osteotomy is to correct excessive anterior tilt angle and neck stem angle.
Postoperatively, the hip was fixed in herringbone plaster for 6 weeks. For children over 5 years old, plaster fixation for 3 weeks followed by bilateral lower extremity abduction skin traction for 3 weeks was feasible to prevent joint stiffness. X-ray examination was performed to confirm the healing of the osteotomy, the absence of AVN, and the resumption of walking. The hip joint development should be reviewed by annual radiographs until bone maturity.
IV. Older DDH over 8 years old
1.Clinical manifestations and signs: In addition to the above manifestations, attention should be paid to the presence of fatigue pain and children with subluxation, joint movement end-extrusion pain, etc.
2.Imaging: X-ray orthopantomogram of both hips, the same evaluation index as before, and should pay attention to the presence or absence of osteoarthritis in the semi-dislocated joint. 3D CT reconstruction can also evaluate the morphological adaptation of the head socket, in addition to the observation of anterior tilt angle and posterior dislocation.
3. Treatment: there is controversy. The aim of treatment for unilateral dislocation is to maximize the restoration of anatomy and function and to create conditions for joint replacement. Equalization of lower limb length prevents secondary spinal deformity. The prognosis of surgical complications in bilateral dislocation without pseudosocket formation is inferior to the natural prognosis, and treatment can be abandoned. Bilateral dislocation with pseudoacetabular formation is prone to early onset arthritis, and palliative treatment is feasible.
Palliative treatment is abandoned for repositioning, commonly used procedures are Chiari surgery, surgery, acetabular expansion slot extension, Staheli, surgery, Shanz osteotomy sub rotor abduction osteotomy, surgery.
Surgical treatment of older DDH. The indications are not clear, the surgical operation is difficult, the surgical complications are many, and the efficacy is uncertain, so it should be used with caution and with the participation of an experienced and dedicated surgeon.
V. Diagnosis and treatment of acetabular dysplasia
It can be seen in all age groups and can be primary or secondary after closed/incisional repositioning,.
1, clinical manifestations and signs: mostly asymptomatic, late stage may have hip fatigue or pain. Few positive signs, but end-of-motion pain should be noted, suggesting Menhaden lip injury.
2.Imaging: X-ray double hip orthopantomograph CEA>20°, cephalic socket coverage <80%. faux postural pseudolateral, film, to understand the development of acetabular anterior margin. ct 3D reconstruction.
3, treatment: acetabular dysplasia has the possibility of improving with development. If there are no imaging changes of early osteoarthritis and/or subluxation, close follow-up observation is possible. Every six months to a year, if there is no improvement and early osteoarthritic changes, external osteotomy of the joint capsule should be performed. If the dislocation is interrupted by the Shenton’s line, both hips should be taken in abduction ≥20° and orthopantomogram. If the hip can be centrally repositioned, external osteotomy should be performed; if it cannot be neutrally repositioned, then an incision and osteotomy should be performed. The choice of osteotomy site and operation style is based on whether the hip is centrally repositioned, the adaptation of the head and socket and the developmental potential.
Significantly maladapted cephalic socket, large socket and small head: acetabuloplasty.
Basic adaptation of the cephalic socket: surgery to change the orientation of the acetabulum; e.g., Salter osteotomy, triple osteotomy, periacetabular osteotomy PAO,Ganz, rotational acetabular osteotomy RAO, etc.
Non-spherical adaptation of the cephalic socket: acetabular enlargement and extension, Staheli surgery, and internal pelvic displacement osteotomy.
Proximal femoral deformity predominant: proximal femoral osteotomy inversion, de-rotation,. or combined surgery.
Postoperative braking or weight-free joint mobility training, as appropriate, until the osteotomy heals and walking resumes. Continue observation until bone maturity.