(C) 18 months to 8 years old (walking age)
1.Clinical manifestations and signs: limp, duck walk; unequal lower limbs, increased lumbar anterior convexity, 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 (round ligament, transverse menhaden ligament, avoid removing the menhaden lip), return of the femoral head into the true acetabulum to achieve concentric repositioning, and V-shaped capsule tightening and molding.
(2) Pelvic osteotomy selection: any kind of pelvic osteotomy cannot treat DDH, and 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 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 and sub-rotor) shortening osteotomy is to reduce the inter-acetabular pressure and 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. In children over 5 years old, to prevent joint stiffness, plaster fixation was feasible for 3 weeks followed by bilateral lower extremity abduction skin traction for 3 weeks. 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 annually until bone maturity.
(IV) Above 8 years old (older DDH)
1. Clinical manifestations and signs: In addition to the above-mentioned manifestations, attention should be paid to the presence of fatigue pain and (in children with subluxation) joint movement end-extrusion pain.
2. imaging examination: X-ray double hip orthopantomographs, assessment indexes as before, and should pay attention to the presence or absence of osteoarthritic manifestations in the semi-dislocated joints. three-dimensional CT reconstruction can also assess the morphological adaptation of the head socket in addition to observing the anterior tilt angle and posterior dislocation.
3. Treatment: recommendations exist. The aim of treatment for unilateral dislocation is to maximize anatomical and functional restoration and to create conditions for joint replacement. Equalization of lower limb length prevents secondary spinal deformities. The prognosis for surgical complications in bilateral dislocations without pseudosocket formation is inferior to the natural prognosis and treatment may be abandoned. Bilateral dislocation with pseudoacetabular formation is prone to early onset arthritis, and palliative treatment is feasible.
The common procedures for palliative treatment (abandonment of repositioning) are internal pelvic displacement osteotomy (Chiari procedure), acetabular expansion (slot extension, Staheli), and Shanz osteotomy (subrotor abduction osteotomy).
Surgical treatment of older DDH. The indications are not clear, the surgical operation is difficult, there are many surgical complications, and the efficacy is uncertain, so it should be used with caution and with the participation of experienced and dedicated surgeons.
(E) 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, with hip fatigue or pain in the late stage. There are few positive signs, but end-of-motion pain should be noted, suggesting Menhaden’s lip injury.
2. Imaging examination: X-ray double hip orthopantomograph CEA>20°, cephalic socket coverage <80% .Faux posture (pseudo-lateral) film to understand the development of the anterior border of the acetabulum.CT 3D reconstruction.
3. Treatment.
Acetabular dysplasia has the potential to improve with development. If there are no imaging changes of early osteoarthritis and/or subluxation, close follow-up observation is possible. If there is no improvement and there are early osteoarthritic changes, external osteotomy of the joint capsule should be performed. In case of subluxation (interruption of Shenton’s line), additional orthopantomographies of both hips (≥20°) should be taken, and if central repositioning is possible, external osteotomy should be performed.
The choice of osteotomy site and procedure is based on whether the hip is centrally repositioned, the adaptation of the head and socket, and the developmental potential.
Significant cephalo-acetabular maladjustment, large acetabulum 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 head socket: acetabular enlargement (extension) (Staheli procedure), 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.