15. Perthes disease

Essay 15- Perthes disease

Definition

• Legg-Calve-Perthes disease is idiopathic avascular necrosis of the femoral head

Etiology

• Cause is unknown
• May be idiopathic
• RF:
• Microtraumas
• Bleeding disorders
• Genetics (COL2A1 gene mutations)
• Environmental factors (maternal smoking etc)

Pathophysiology

• There are 4 phases:
• Necrosis- disruption of the blood supply leads to infarction of the femoral capital epiphysis, particularly the subchondral cortical bone.
• Fragmentation- the body reabsorbs the infarcted bone.
• Reossification- osteoblastic activity takes over, and the femoral epiphysis reestablishes.
• Remodeling- the new femoral head may be enlarged or flattened. It reshapes during growth

Catterall classification (to determine treatment)

• Group 1- Only the anterior part of the thigh epiphysis is affected, there are no metaphyseal changes
• Group 2- The ischemic segment is consolidated but at the sides there are zones of a healthy bone protecting the head from a collapse, metaphyseal changes are slight
• Group 3- About 3/4 of the epiphysis is affected. There is no preserved lateral column of a healthy bone, marked metaphyseal changes
• Group 4- The epiphysis is totally affected. The collapse is severe and occurs early, the metaphysis is cystic

Lateral pillar classification

Symptoms

• At the onset the disease develops unnoticeably, slowly and insidiously.
• Slight, intermittent pain
• Gradually, pain becomes aggravated upon exertion and children start limping
• When complaining of the pain in the hip, the child often points at the knee (propagation of the pain along n. obturatorius).
• Easy fatigue
• Restricted range of movement
• Positive FABER test (maybe)
• No systemic symptoms should be found
• Antalgic gait (on weight bearing leg)
• Trendelenburg gait (chronic)

Diagnosis

• Physical exam
• X-ray:
• In the initial stage, the distance between the thigh head and the bottom of the acetabulum becomes larger
• In the full swing of the disease, fragmentation of the nucleus is observable together with shortening and widening of the cervix and the appearance of cysts on the epiphyseal gap
• During the recovery stage, the contours of the epiphyseal nucleus are well-delineated but it is wider and lower, the cervix is wide and very shortened
• Complete blood cell count to exclude other pathologies

Treatment

• Aimed at preserving the thigh head from deformities and preserving the normal growth of the epiphiseal cartilage lamella
• Achieved by continuous decompression of the joint by means of extension, special splints, a special Thomas' device!

Non-operative

• Activity restriction and protective weight-bearing
• NSAIDs
• Physical therapy

Operative

• Femoral or Pelvic Osteotomy
• Valgus or Shelf Osteotomies
• Hip Arthroscopy