DevelopmentalDysplasiaoftheHip (DDH), formerly known as CongenitalDislocationoftheHip (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 spinal deformities in children, leading to lower back pain and pain caused by degenerative hip joint degeneration in adulthood. The goal of DDH treatment is to achieve a stable concentric reposition and avoid ischemic necrosis (AVN) of the femoral head. Early diagnosis and treatment are the keys to improve the outcome.
I. Birth to 6 months.
This stage is the prime time for DDH treatment, with simple and easy methods, 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, etc. Ortolani/Barlow 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 (AL), central marginal angle (CEA), Shenton line, tear drop (Teradrop) sign.
3, Treatment.
Prefer Pavlik sling to maintain hip flexion 100° to 110° and abduction 20° to 50°. 24 hours maintenance. Prohibit dislocation movements (including examination and dressing change). Regular ultrasound examinations, 1 time/1 to 2 weeks. If ultrasound suggests obtaining concentric repositioning after 3 weeks, continue maintenance for 2 to 4 months. An abduction brace was then used until the acetabular index (AL) was <25° and the central marginal angle (CEA) was >20°. If ultrasound and clinical examination after 3 weeks suggest that no reduction has been achieved, the Pavik sling is discontinued and other treatment is used instead. Otherwise, persistent compression of the acetabular wall by the posteriorly dislocated femoral head can lead to sling disease (dysplasia of the posterior acetabular wall).
Other treatment methods include bracing (fixed position as sling) or direct closed cast fixation. Non-anesthetic repositioning and wearing extreme (frog) abduction brace are contraindicated to avoid damage to the femoral head cartilage and AVN.
Second, 7 months to 18 months.
With the increase of age, weight and activity, the compliance and efficacy of using the sling decreases.
1. Clinical manifestations and signs.
In addition to the above manifestations, physical examination reveals asymmetrical appearance of both hips, wide perineum, high greater trochanter, positive telescope sign (telescope sign) and Allis sign.
2. Treatment.
The preferred treatment is closed repositioning under anesthesia and plaster tube fixation in human position. Before closed repositioning, the internal longus muscle should be cut or percutaneously, and if necessary, the iliopsoas tendon should be cut at the same time, and repositioned by gentle Ortolani technique. The observation index is a safezone >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 reset. Abandon closed reduction and use transmedial approach (Ludolff, Ferguson) or anterolateral approach (Bikini, S-P) for incisional reduction 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 in a plaster cast or brace for 3-6 months.
At the end of the above treatment, the sick child has the following conditions.
(1) Concentric repositioning of the head and socket and observation; films are taken every six months.
(2) The head socket is repositioned, but the residual acetabulum is dysplastic, as shown by steep and straight acetabulum with AI > 24°, but the Shenton line is continuous, and an abduction brace is worn, especially at night; films are taken every 4 months to observe the improvement of acetabular inclusion (AI, CEA) or the presence of subluxation.
(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. If the radiographs show persistent subluxation (discontinuity of Shenton’s line), surgical correction is indicated; if improvement persists, the treatment is the same as (2).
(4) For residual AVN, the affected femoral head should be placed under the inclusion of the acetabulum to allow for repair and contouring. The specific treatment is the same as (2) and (3).
Third, 18 months to 8 years old (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 examination.
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.
Closed repositioning is still possible 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), the femoral head is also incorporated into the true acetabulum to achieve concentric repositioning, and V-shaped capsule tightening and molding.
(2) Choice of pelvic osteotomy.
Any kind of pelvic osteotomy cannot treat DDH, and its 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) Short reduction osteotomy of the proximal femur (inter-rotor and subrotor).
It is to reduce the intercranial 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. Review the development of the hip joint until bone maturity by annual radiographs.
Fourth, over 8 years old (older DDH).
1. Clinical manifestations and signs.
In addition to the above manifestations, attention should be paid to the presence or absence of fatigue pain and (in children with subluxation) end-motion extrusion pain of the joint.
2.Imaging examination.
X-ray orthopantomogram of both hips, the same evaluation index as before, and should pay attention to the presence 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.
Recommendations exist. 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 deformities. 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.
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.
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 fatigue or pain in the hip. Few positive signs are present, 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 postural (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 early osteoarthritic changes are present, external osteotomy 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; if neutral repositioning is not possible, incision and 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.
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 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.