Legg-Calvé-Perthes' disease FRCS

Prognosis depends on what factors?

Bone age clinical picture Lateral pillar classification

What are the two classic signs and symptoms?

Hip / knee pain and effusion Decreased hip ABDuction and internal IR rotation Limping child

The relevance of the lateral pillar is in relation to the likelihood of containment of the hip

If it remains intact the lateral pillar acts as a buttress preventing subluxation of the head. Therefore, extensive lateral pillar involvement makes it much more likely that containment procedures will be required

What classification system is based on the fragmentation stage of disease? usually occurs 6 months after the onset of symptoms

Lateral pillar classification (Herring Lateral Pillar Classification)

BOSS trial

The British Orthopaedic Surgery Surveillance (BOSS) Study is a nationwide reporting mechanism to determine the epidemiology and outcomes in rare orthopaedic diseases PERTHES and SCFE

Types of epiphysial dysplasia?

The most likely candidates would be multiple epiphyseal dysplasia (MED) or spondyloepiphyseal dysplasia (SED)

If the hip is unstable in abduction

adductor tendon release Consider proximal femoral VARUS derotation osteotomy UNLESS if it is hinge abduction of the hip which needs a VALGUS producing osteotomy to contain the hip

Non op indications/tx (supervised neglect)

children < 8 years of age (bone age <6 years) young patients typically do not benefit from surgery lateral pillar A involvement containment + ROM NSAIDS, NWB, PT for ROM Bracing/ Casting- studies show does not help

Operative Treatment/indications

children > 8 years of age, especially lateral pillar B and B/C

The lateral pillar classification is assessed on what film?

AP pelvis

What are the two characteristics of the population at greatest risk?

Boys 4 to 8 2-year delay in skeletal maturity

What is the general goal of management?

Establish a: - pain-free - stable - concentrically reduced hip / contained for normal acetabular development and delay the early onset of OA Dynamic containment

If the hip unstable to rotation

Pelvic osteotomy - Age of the child/open triradiate cartilage - intact posterior column - Neuromuscular disorder? ( salvage)

Definition

Perthes' is an idiopathic avascular necrosis of the femoral head in childhood

Pelvic osteotomies basic principles

Reconstruction: volume reducing: if the shape of the acetabulum is shallow, not correct Redirection: if the shape is right and looks in the wrong direction Salvage:

VDRO concerns

Warn the family preoperatively that either real or apparent limb shortening may be seen postoperatively. Be certain the child has full hip motion, and use an arthrogram to check that the hip is congruent. Do the osteotomy fairly early after the diagnosis, not during the remodeling stage. Warn the family that a valgus osteotomy may be needed later to improve hip abduction. Do not create too much varus. Keep theneck shaft angle at 115° (or more) or the child will limp for a longtime (warn the parents!).

if the hip is not containable...

cheilectomy (open or arthroscopically) and proceed

if the hip becomes containable after cheilectomy...

containment procedures: - PFO - pelvic osteotomies - ex-fix

How does bone remodeling occur?

creeping substitution

If both hips are identically involved

epiphyseal dysplasia . do a skeletal survey

Role of EUA and arthrogram?

establish 2 things: - sphericity / shape of the femoral epiphysis - containment of the hip / congruency and STABILITY

operative treatment

femoral and/or pelvic osteotomy proximal femoral varus osteotomy (VDRO) / PFO Salter or triple innominate osteotomy Shelf arthroplasty may be performed to prevent lateral subluxation and resultant lateral epiphyseal overgrowth

if the hip is containable after dynamic arthrogram?

preventive, containment procedures: - PFO /VDRO ( if containabe in abduction) - Shelf pelvic osteotomy ( if c - arthrodiastasis with ex-fix

if the hip remains non-containable..

salvage procedures: - PFO ( abduction + extension) - shelf pelvic osteotomies - osteoplasty

timing of femoral varus osteotomy

studies sugggest earlier surgery before femoral head deformity develops may be best

Summary of management

symptom control/ NWB/ physio / supervised neglect consider assses for red flag signs " head at risk" signs clinical : FOOBS + pain Radiological : investigate with EUA + arthrogram surgery

Hip motion improves during:

the Reossification phase (growing period)

The most important good prognostic indicator

younger age (bone age) < 6 years at presentation other are: - clinical picture ( heaad and risk signs) - lateral pillar classification -Herring

Catterall identified three age groups:

<6 years - Will typically do well unless there is severe involvement of the head 6 - 8 years - Will typically benefit from containment surgery unless very mild head involvement >8 years - Will typically do badly without surgery unless very minimal head involvement. Those with Herring C hips are thought to do so badly that it is questioned whether surgery is of benefit at all in this age group

'Head at risk' signs: Clinical:

- Female - Older age - Obesity - Bilateral disease - Stiffness: Decreased range of motion or recurrent admissions for pain / Adduction contracture in extension/ Flexion with abduction

Prognosis based on Stulberg?

- For types 1 and 2, the prognosis is not that much worse than for the general population. - Type 3 hips may require a total hip replacement approximately 10 years earlier than controls. - type 4 and 5 hips degenerate quickly and will likely need a hip replacement before 50

Stulberg classification

- Gold standard for rating residual femoral head deformity and joint congruence - Recent studies show poor interobserver and intraobserver reliability

Lateral pillar classification (Herring Lateral Pillar Classification)

- Group A • lateral pillar maintains full height with no density changes identified • consistently good outcome - Group B • maintains >50% height • poor outcome in patients with bone age > 6 years - B/C Border• lateral pillar is narrowed (2-3mm) or poorly ossified with approximately 50% height• recently added to increase consistency & prognosis of classification - Group C • less than 50% of lateral pillar height is maintained • poor outcomes in all patient ages

Management - non-op

- NWB , offl-oad the affected extremity , avoid further harm - check ROM and try to preserve it with physio - symptoms control ( supervised neglect) - investigate further ( EUA arthrogram) if at risk sign are present

factors determine the containment

- clinical picture clinical head at risk signs FOOBS at risk sign + pain - Age < 6y : good prognosis > 8y poor outcome - Head involvement ( the more, the worse the prognosis)

Management - surgical

- containment - reconstruction - salvage

Containment options

- proximal femoral osteotomy - acetabular augmentation - arthrodiastasis

important prognostic variables

- younger age (bone age) < 6 years at presentation is most important good prognostic indicator - sphericity of femoral head and congruency at skeletal maturity (Stulberg classification) - lateral pillar classification

'Head at risk' signs: Radiological

1) Calcification lateral to the epiphysis 2) Metaphyseal cysts 3) Increased medial clear space (signalling lateral subluxation) 4) Horizontal physis 5) Gage sign (lucent v-shaped defect in the lateral aspect of the physis) 6) Lateral translation, subluxation of the femoral head

Waldenstrom described the stages of disease as follows

1) Initial 2) Fragmentation 3) Reossification 4) Healed or remodeling

Stulberg classification (risk of developing OA 40s)

1- Normal(0%) 2- spherical head with enlargement, short neck, steep acetabulum(16%) 3- non spherical head (58%) 4- flat head(76%) 5- flat head with in-congruent hip joint(78%)

treatment if clinical or radiological head at risk signs exist?

EUA and arthrogram

Important work-up for treatment plan?

EUA and arthrogram (dynamic arthrogram)

Operative treatment is generally beneficial only in what stage of disease?

Fragmentation

What classifcation system is based on initial stage of disease?

Salter-Thompson classification This system is based on the extent of the subchondral fracture line on the frog-leg lateral film Unfortunately it only applies to the initial stage, and the subchondral fracture line (crescent) is seen in fewer than 50% of cases

How would you assess the hip at maturity?

The Stuhlberg classification gives prognostic information at skeletal maturity. It divides hips into five categories: Types 1 and 2 are largely spherical and congruent Type 3 is aspherical but congruent Types 4 and 5 have misshapen femoral heads and the joint in non-congruent

laterality

The disease is bilateral in 15% of cases; however, it is never completely synchronous or symmetrical.

Hinge abduction of the hip sign in the MUA arthrogram is defined as

The hip joint articular surfaces are not concentric The femoral head hinges at the acetabulum during the ABduction and the medial space is inceased

demographics

The male : female ratio is 6 : 1, and the most common age of presentation is 4-8 years

Aetiology

The prevailing opinion is that Perthes' is a multifactorial disease with genetic and environmental factors playing a role - Genetic inheritance - thrombophilia - vascular deficiency - Environmental factors - Endocrine anomalies

What is the usual gait pattern?

Trendelenburg