Paediatric hip disorders -2

July 18, 2020 0 By FM

Case1:

A 2-year old female child came with unreduced left hip dislocation. The x-ray picture is given. (Fig 1)

We have done open reduction, adductor and psoas tenotomy, femoral varus de-rotation osteotomy after shortening of femur along with capsuloraphy. 

The approach of open reduction was Somerville approach. 

Surgical Indication

 “Surgical option is indicated by pathology rather than by the age.”

Make a straight skin incision beginning anteriorly inferior and medial to the anterior superior spine and coursing obliquely superiorly and posteriorly to the middle of the iliac crest.

What is DDH?

DDH-Developmental Dysplasia of Hip

CDH-Congenital Dislocation of Hip

CDH-Congenital Dysplasia of Hip

DDH comprises a wide spectrum of hip abnormalities ranging from mild acetabular dysplasia to complete dislocation of the hip.

Aetiology:

Aetiology is multi factorial in origin. 

  1. Physiological factors: Ligament laxity, 
  2. Genetic factors: Female children have 4 to 6 times higher risk to develop DDH, monozygotic twins have outnumbered dizygotic twins. If a second degree relative get affected a 1 in 100 risk to this particular child exists and if one parent is affected 1/8 or one sibling affected 1/18 risk exits.
  3. Mechanical Factors: Breech position – A double breech position is associated with a low incidence of DDH. A single footling breech is associated with a 2% risk of DDH. A frank breech, especially with the knee(s) extended, is associated with a 20% risk of DDH. Pregnancies complicated by oligohydramnios is also a risk factor.

Associated findings: Down’s syndrome, torticollis (15%-20%), metatarsus adductus (1.5%-10%). Clubfoot has not been shown to have a significant relationship to DDH.

Who is a child at risk?

First female child with positive family history of DDH in frank or single breech presentation with signs of intra uterine crowding like metatarsus adductus or calcaneo-valgus and having knee hyper extension is a child at risk.

Natural history of untreated DDH

A substantial percent of hip dysplasia exists in population and up to 50% of hip arthritis in ladies have underlying hip dysplasia contributing to adult osteo arthritis. Hip instability at birth accounts to 0.5 to 1 % of infants and classic DDH 0.1%. Left hip is more often involved than the right because of the most common intrauterine position of the left hip adducted against the maternal sacrum. 

Normally a newborn child has coxa valga and increased femoral antevertion. As the child grows and starts weight bearing the antevertion and neck shaft angle decreases. Due to abnormal pattern of weight transmission excessive valgus and antevertion persists in children with DDH. Muscle imbalance can also significantly affect the growth and morphology of the upper femur. Excessive adductor pull or inadequate abductor muscle function results in a valgus deformity to the upper femur.

Centre edge angle of Wiberg (CE angle of Wiberg) provides useful information regarding development of acetabulum and degree of displacement of the femoral head. For CE angle ; AP radiograph should be made at standing in neutral rotation, mark the centre of femoral head, angle formed by a line drawn from the centre of the femoral head to the outer edge of the acetabular roof, and a vertical line drawn through the centre of the femoral head are necessary. Angles greater than 25 degrees are considered normal and less than 20 degrees indicates severe dysplasia.

The muscles around the hip get contracted and become shortened. Iliopsoas tendon becomes interposed between the femoral head and acetabulum blocking reduction. The hip joint becomes more dysplastic and filled with fibro fatty tissue (pulvinar). The capsule becomes redundant and expanded. An arthrogram may show an hourglass constriction of the joint capsule caused by the contracted iliopsoas, which blocks hip reduction. Ligamentum teres becomes lengthened, hypertrophied and redundant. The femoral head and neck remain anteverted and in valgus position. Head becomes misshapen and flattened with delayed ossification of the epiphysis. Acetabular labrum becomes elongated and hypertrophied and may in-fold into the joint (inverted limbus) block reduction of the femoral head. Abnormal femoral head and false acetabulum develop in the ilium wing. Transverse acetabular ligament contracts and is a major block to a deep concentric hip reduction.

Five radiological features of DDH

  1. Break in Shenton’s line
  2. Increased acetabular index (normal is < 25°; > 30° indicates dysplasia, significant if > 40°)
  3. Delay in appearance of the ossific nucleus of the femoral head
  4. Lateral and superior migration of the femoral neck
  5. Delayed ossification: U figure or teardrop of Kohler

Graf’s method of assessing DDH

Graf used ultrasound for assessing DDH. Graf’s Hip angle measurements are based on three lines and two angles 

  1. Baseline is drawn on the ilium to the junction of the cartilaginous roof and bony acetabular roof 
  2. Bony acetabular roofline 
  3. Cartilaginous roofline.

The alpha (a) angle is formed by the bony acetabular roofline and the iliac line.

The beta (b) angle is between the baseline and the cartilaginous roofline.

In the normal hip a angle is more than 60°, and the smaller the angle the greater the dysplasia. When b Normal < 55°more than 77° the hip is subluxed and the labrum is everted. The hip ratio measurement calculates the percentage of femoral head coverage under the bony roof.

Graf ultrasound classification

Four types of hip are described based on the depth and shape of the acetabulum as seen on coronal image. 

Type I: Normal hip.

Type II: Shallow acetabulum with a rounded rim. Immature (physiological) hip spontaneously resolves in infants < 3 months old. Mildly dysplastic in infants > 3 months old persists without treatment.

Type III: Subluxated or low dislocation. Bony roof deficient, labrum everted.

Type IV: High dislocation. Flat bony acetabulum. Labrum interposed between femoral head and lateral wall of the ilium.

CLINICAL FINDINGS

  1. Trendelenburg gait (Waddling gait in B/L)
  2. Increased lumbar lordosis
  3. Higher buttock fold on affected side
  4. Buttocks are broad & flat (B/L)
  5. Perineal space is widened (B/L)
  6. Greater trochanters are elevated & more prominent than normal
  7. Positive vascular sign of Narath
  8. Head of femur palpable in the gluteal region
  9. Adduction contracture
  10. Movements : Restricted abduction & increased internal rotation
  11. Supra-trochanteric shortening
  12. Positive Galeazzi sign
  13. Positive Barlow’s & Ortolani’s sign
  14. Telescopy sign positive

Aim of treatment

The earlier the treatment is started, the more likely is the successful result.

Goals of Treatment

  1. To achieve and maintain early concentric reduction and to prevent future degenerative joint disease. Concave acetabulum cannot develop without concentric force exerted by the reduced femoral head.
  2. During first few months, redevelopment of acetabulum is the normal response of pressure of femoral head within it. The parts are still mainly cartilaginous and plastic and are easily molded by restoring normal anatomical and physiological conditions. 

Up to age 1 yr, concentric reduction generally results in normal hip. 

Up to age 4 yrs, reduction along with operative correction of acetabular dysplasia or correction of femoral ante version can lead to normalization of the hip.

Basic principles

At birth usually the acetabulum is dysplastic which is shallow and more vertical, with the roof deficient anteriorly and laterally. 

Femoral head slips out of its socket when the hip is extended and adducted. Dysplasia becomes worse, the head & neck become progressively misshapen as long as abnormal acetabulo-femoral head relationship is permitted to exist. Restoration of femoral head to its normal position will reverse the process. The earlier this is accomplished the more normal will be the final result. The reduction should be gentle & the joint should not be positioned under strain. Continuous forcible compression of the articular surfaces should be avoided, to prevent ischemic necrosis & irreparable damage of articular cartilage. Tight adductors should release by subcutaneous tenotomy. After reduction maintaining flexed & abducted position of hip is mandatory. Maintaining internal rotation for prolonged periods will increase the degree of antevertion of femoral neck. Closed reduction of high dislocations, especially if delayed, requires preliminary traction and routine sub-cutaneous adductor tenotomy at the time of reduction to reduce the incidence of ischemic necrosis of femoral head. 

Here is an example of closed reduction done in a case of DDH and maintained the position in flexed abducted and internally rotated.

RAMSEY, LASSER & MACEWEN safe zone concept

The hip is reduced by flexion more than 90 degree and gradually abducted with gentle lifting of greater trochanter with minimal force. After reduction, determine the range of motion in which it remains reduced. The hip is adducted to the point of re-dislocation that point noted. Hip again reduced, and extended until dislocates, that point also noted. If hip requires internal rotation to maintain reduction, that point is also noted. The range of motion in which it remains reduced is compared to max range of motion. From this information, safe zone is constructed. Safe zone is used in determining the zone of abduction & adduction in which femoral head remain reduced in the acetabulum. Wide safe zone is desirable. Narrow safe zone is unstable hip. Adductor tenotomy increases safe zone. After confirmation of stable reduction hip spica cast is applied, this can be removed after 6 weeks of immobilisation. Salter advised Human position for plastering. More than 90-degree flexion and 40-45 degree abduction is advantageous in minimising the risk of avascular necrosis. 

Indications of open reduction in DDH 

  1. Femoral head lying persistently above triradiate cartilage
  2. Femoral head lying laterally > 6weeks
  3. Previous failed reduction

Complication of open reduction in DDH 

1. Avascular necrosis. Traction and femoral shortening prevent excessive compression of femoral epiphysis and will prevent AVN.

Treatment Guidelines

Neonate: Place in Pavlik Harness for 6 weeks. The indication is a hip that is dislocated and that can be reduced by the examiner (+ve ORTOLANI TEST). Abducting the hip causes the femoral head to descent towards the center of acetabulum, where pressure forces cause the socket to deepen and a roof to form. In unilateral or bilateral, both hips are maintained in abduction. 

1 to 6 months: Place in Pavlik harness for 6 weeks after hip reduction. Various devices that maintain flexion and abduction of hip are in use in children during the first 6 months of life. First few months there exists a success rate of 85% – 95%. Czechoslovakian orthopedic surgeon Arnold Pavlik devised it. It is the only appliance which will promote the spontaneous reduction of a dislocated hip and maintain that reduction whereas other appliances will only maintain reduction. So, it is called as dynamic flexion abduction orthosis. Pavlik harness promotes spontaneous reduction of dislocated hip by positioning in flexion, while allowing free abduction, thus minimising the risk of avascular necrosis. Another device is Von rosen splint, H shaped splint which keeps hip in flexed position and held loosely in 90 degree, and not more than 45-degree abduction.

The contra-indications of Pavlik Harness

Infants with a “hip click” but a normal physical exam (Barlow’s test and Ortolani’s test), teratologic dislocation, child is in walking age.

6 to 18 months: Traction, closed reduction. If closed reduction is successful, place in cast for 3 months. If closed reduction is unsuccessful, perform open reduction. Open reduction is performed by a medial approach in children younger than 12 months of age and by an anterolateral approach in children older than 12 months of age.

18 to 24 months: Trial of closed reduction, or primary open reduction (anterolateral approach). A Salter osteotomy may or may not be part of the procedure.

6 months – 2 yrs: Treatment in this age group should follow a standard regimen. Pre-operative traction, adductor tenotomy followed by closed reduction. Arthrogram is helpful to find out the completeness of reduction. We routinely don’t do arthrogram. Accept reduction if medial dye pool of 7mm or less in arthogram. We have to maintain reduction in an acceptable safe zone. If closed reduction is not successful open reduction and maintanence of the reduction with Steinman pin or thick K-wire and hip spica become mandatory.

Role of preliminary traction in improving reduction and reducing the incidence of avascular necrosis is controversial. For many years, pre-operative traction was considered essential to reduce the incidence of avascular necrosis of femoral head. Hip held in 20-30-degree flexion by means of frame and traction applied with adhesive tapes. Continued until the
head is below Hilgenreiners line, often requires 3 weeks or more.

The obstacles for reduction of hip in DDH

  1. Femoral head and neck remain anteverted and in the valgus position
  2. Muscles crossing the hip joint (hamstring, hip adductors, and psoas) become shortened and contracted
  3. Psoas crosses acetabulum, blocking reduction
  4. Arthrogram may show hour glass configuration of joint space 
  5. Hip joint filled with fibrofatty tissue known as pulvinar
  6. Acetabular labrum: Becomes enlarged along the superior, posterior, and inferior rim and may in fold into the joint (inverted limbus), limbus blocks reduction of femoral head into the acetabulum, acetabulum becomes flattened (dysplastic) because it is not stimulated to develop around the absent femoral head.
  7. Ligamentum teres becomes lengthened, hypertrophic and redundant.
  8. Transverse acetabular ligament – pulled superiorly with capsule which blocks lower portion of acetabulum. 
  9. Capsule of hip joint – expanded, peri-cephalic insertion and adhesions.

24 months to 6 years: Perform primary open reduction (anterolateral approach) and femoral shortening, with or without a Salter osteotomy. 

Simple pelvic osteotomy that repositions acetabulum – Salter, Pemberton, Dega osteotomy. 

Complex osteotomy that repositions acetabulum – Steel, Ganz, Tonnis osteotomy.

Osteotomy that augment acetabulum – Chiari, Shelf procedures

Case 3:

Salter Innominate osteotomy:

Redirection of acetabulum as a unit by hinging and rotation through the pubic symphysis, which is mobile in children, so that its roof covers the femoral head both anteriorly and laterally.

We have done a Salter Osteotomy in a 2.5 year-old-child. (Fig 10)

Indication:

Acetabular dysplasia persisting after primary treatment.

Acetabular dysplasia discovered in untreated child.

Failure of acetabular angle to improve within 2yrs.

Persistent dysplasia after the age of 5 yrs.

Appropriate for children between 2-9 yrs. children < 18 months do not have iliac wings which is thick enough to support bone graft. Older than 9 years failure of movement of acetabular fragment to adequately cover femoral head. Acetabular angle will be improved by an average 10 degree by Salter.

Contra indications:

Severe dysplasia

Patient with non – concentric hips

Complications:

Sciatic nerve injury.

Femoral nerve injury.

Pin in acetabulum. Pin in femoral head causes hip stiffness.

Kalamchi modification of Salter: Displacement of distal fragment into a posterior notch in the proximal fragment to avoid increasing the pressure on femoral head.

Complications:

Premature closure of tri-radiate cartilage.

Damage to acetabular growth centre.

The aims in doing on osteotomy in osteoarthritis hip:

  1. Relieve pain
  2. Restore motion
  3. Correct deformity
  4. Restoration of stability
  5. Reversal of degenerative process

The indications for valgus osteotomy:

  1. Trendelenberg limp
  2. Adduction deformity
  3. Adduction beyond adduction deformity
  4. Extension may be obtained by taking the wedge posteriorly

Case 4: 

Shelf procedure:

It is performed to enlarge the volume of acetabulum. Slotted acetabular augmentation of Staheli -Wilson shelf procedure.

We have done shelf procedure in a DDH child of 6-year-old. The post-operative X-Ray is shown below.

Case 5

A 15 year old person came to us with pain while walking. It was a neglected case of DDH. The natural history of untreated case follows the path of mechanical pain while walking and shortening of limb. Later secondary osteoarthritis hip can be developed.

The X-Ray of him is shown below. (Fig 12)

Shanz osteotomy:

The pelvic support osteotomies in unstable hip:

  1. Shanz osteotomy
  2. Mitch Batchelor osteotomy – resection arthroplasty with pelvic support

Femur is angled to align the upper fragment with the side wall of the pelvis and the lower fragment parallel with the axis of weight bearing. This is an abduction osteotomy done at the level of the ischial tuberosity to get pelvic support.

Indications:

  • Palliative procedure in irreducible cases.
  • Older children with neurogenic dislocations where  reconstructive surgery is not indicated.

The complications of doing a Shanz osteotomy:

  • Increased valgus -The osteotomy apex may contact the acetabulum and may produce pain
  • Genu valgum and external rotation may develop as compensatory deformities.

Tuberculosis of hip

A male child of 9 years came with severe painful right hip. On examination he had 40 degree fixed deformity of rt. hip and attempted movements were painful. Medial side of thigh there was a soft tissue swelling. It was cold abscess. No fever, no family history of tuberculosis. Child was malnourished.

We took routine blood investigations, the ESR was 20, and we expected a little more ESR value. We took all pre anaesthesia check up and X-ray pelvis with both hips AP and frog leg lateral views, Mantoux test, chest X-ray and sputum examination for AFB. X-ray showed reduced joint space. In advanced cases we can expect destruction of acetabulum or femoral head, proximal migration of head, or even frank dislocation. In active stage of the disease the entire hip will be severely osteoporotic. If a lesion has to be seen in X-ray at least 40% demineralization has to occur. The pre-destructive lesions, abscess and the extend of the lesion particularly are best visualised in MRI. 

Cold abscess is the combined result of tuberculous infection as well as due to reactive exudative process. It usually composed of serum, leucocytes, caseous material, bone debris, tubercle bacilli etc. In hip tuberculosis, usual sites of cold abscess are in the front of hip in the femoral triangle, in the medial side of thigh, posteriorly in the gluteal area, laterally in the trochanteric region, ischio-rectal fossa etc. It may even track down to the knee or even ankle along with neurovascular bundle. From hip joint it may track medially to reach the pelvis. From here it may travel above the levator ani and point above the inguinal ligament or it may track below the levator ani to track into the ischio-rectal fossa. (So, do not forget to do a per- rectal examination of the patient)

A negative Mantoux test practically rules out tuberculosis. A negative Mantoux is also seen in miliary tuberculosis, immuno-compromised state, steroid therapy etc. I would like to confirm the diagnosis. In this case we took biopsy by modified hueter anterior approach and we washed the joint with copious amount of saline. The fluid which we obtained was sent for tuberculosis work up and specimen for histo-pathology examination. One can also aspirate the joint and send the specimen for AFB staining as well as for tuberculous culture and for RT PCR (Reverse transcriptase PCR). Culture can be done either by LJ medium or by Bactec radiometric method. One can also try to get a tissue diagnosis either by a Tru-Cut biopsy. PCR is a polymerase chain reaction. Here DNA of mycobacterium is amplified many fold enzymatically and detected using various methods but it cannot differentiate between live bacteria and dead bacteria. To circumvent this we use bacterial mRNA which has a half life of a few minutes. Using this mRNA we create a complementary DNA strand and amplify this. This is the principle behind reverse transcriptase PCR. So if RT PCR is positive it means the patient is having active tuberculosis. Do not get confused between RT PCR and Real Time PCR. Latter is a faster method of doing PCR where you get result within 30 to 120 minutes. LJ medium culture usually takes an average of 6 weeks to get a positive result. BACTEC radiometric method will usually give a positive result in 3-4 week. But unfortunately culture will be positive only in 30%-60% of the patients. Direct smear examination for AFB will be positive only in less than 10%. 

​Many a times HPE will be reported as granulomatous disease. This can be tuberculosis, mycotic infection, brucellosis, sarcoidosis etc. So it is better to do all these tests to get a better chance of diagnostic yield. BACTEC is a radiometric culture method. Here a culture medium containing palmitic acid labeled with radioactive carbon 14(C14) is used. Mycobacterium will utilize the palmitic acid and in the process radioactive 14CO2 is released which is detected by an ionic chamber.

Usual sequela of osteo articular tuberculosis is fibrous ankylosis. Here there will be a jog of movement at the affected joint and it is extremely painful. Good functional outcome is usually seen in normal type and Perthoid type whereas wandering acetabulum and mortar and pestle type usually gives a poorer outcome.

Treatment:

1. General Nutrition: Improve the nutrition of the patient

2. Specific measures: Revised National Tuberculosis Control Programme of daily regimen. 

ATT: Do a LFT, ophthalmology evaluation and start anti-tuberculous treatment. 

I put the child on traction and started active mobilization of the hip joint as tolerated by him. Usually by 6 months the patient may be able to do a partial weight bearing crutch walking and by 12-18 months the patient may be able to fully weight bear. If patient is not responding for non-operative treatment, do a joint debridement surgery and then continue traction and ATT as usual. In spite of this treatment if it is felt that the joint is going for fibrous ankylosis we may offer either a stable but immobile painless hip or a mobile but unstable painless hip, and treat depending on the patient’s preference. Depending on that do an excision arthroplasty or an arthrodesis of the hip particularly in older age group.

First line drugs: Rifampicin, INH, Pyrazinamide, Ethambutol, Streptomycin.

Second line Drugs: Aminoglycosides (Amikacin, Kanamycin), Quinolones (Ciprofloxacin, Levofloxacin, Moxifloxacin), Ethionamide, Cycloserine, PAS.

Combinations of drugs are given to prevent drug resistance. INH, Rifampicin and ethambutol are bacteriocidal and PZA is weakly bacteriocidal. INH and Rifampicin are very active against rapid growers, where as all the four are active against slow growers. PZA alone can act at acidic media (at the site of abscess and inflammation).

Earlier there was DOTS (Directly Observed Treatment Short course) regime which was a WHO initiative and implemented in India. DOTS uses thrice weekly regimen of R3H3Z3E3 for the initial two months and then R3H3 for next 4 months. In RNTCP, tuberculosis categorized into two categories. CAT 1 is all newly diagnosed cases. CAT 2 is defaulters, relapse and failure cases. Now the programme has changed into a daily basis.

SEQUELAE OF HIP SEPSIS

Sepsis may result in both direct and indirect consequences to one or both sides of the joint. Direct damage to the articular cartilage is common, and if severe, partial or complete joint destruction may culminate in ankylosis. The ankylosis
may be fibrous or bony. If fibrous there may be a jog of movement with pain and if bony there may not be pain or movement or instability from subluxation/dislocation. Indirect consequences result from physeal damage and avascular necrosis. 

In addition to joint destruction, consequences of neglected hip sepsis include joint instability, abductor insufficiency, and leg length discrepancy. Leg length discrepancy results from physeal arrest, joint subluxation/dislocation, and/or mal positioning of the extremity from contracture or ankylosis.

Complications:

  • Destruction of articular cartilage
  • Destruction of the physis
  • AVN
  • Subluxation or dislocation

Long term Sequelae:

  • Deformity
  • Stiffness
  • Instability
  • LLD and Growth disturbances
  • Arthritis
  • Ankylosis
  • Osteomyelitis

2 cases came to our out patient department with long term sequelae of septic arthritis.

1st case: Short limp gait with limb length discrepancy and inability to walk.

(Fig 15)

2nd case: Similar complaint as the previous case, we have given him traction and other supportive medications. Investigations did not reveal any active infection in this case. He doesn’t want any surgical procedure so treated it in conservative methods. The cause of pain in this case was mechanical synovitis. (Fig 16)

CLINICAL POINTS: 

Persons may give history of bad events
in the description of obstetrical and nursing history suggestive of umbilical cord sepsis, intramuscular injections,
and intravenous access for treating any infections, dermatitis and any aspiration or surgical drainage around the hip.

Patients may present with:

  1. Limb length discrepancy (true shortening)
  2. Wasting of muscles
  3. Abductor lurch and movement abnormalities
  4. Pain hip may be due to mechanical or synovitis
  5. Trochanter shifted high up

The poor prognostic factors are:

  1. Infection occurring before 22 weeks of age because the head of femur is mostly cartilaginous and may be completely destroyed by infection
  2. Prematurity
  3. Delay in treatment more than 4 days
  4. Associated osteomyelitis of proximal femur