Paediatric Knee

Original Editors - Daphne Jackson

Top Contributors - Admin, Sheik Abdul Khadir, Kim Jackson, Jerome Ng, Daphne Jackson, Michelle Lee, Jess Bell, WikiSysop, Vidya Acharya and Rucha Gadgil  

Introduction

Knee pain is a common problem in children and adolescents  Knee pain in the paediatric population arises from different underlying pathologies than adults. In adults, the majority of the pain attributes to the degenerative changes and its associated complications, whereas in the paediatric age group, the underlying pathology may be congenital or growth-related pathology. It is also useful to note that children have various anatomical and biomechanical changes to their lower limbs as they mature.

Common Knee Disorders in Children

• Anatomic
  • Discoid Menisci
  • Popliteal Cysts
  • Osteochondritis Dissecans
• Patellofemoral Conditions
  • Patellofemoral Instability 
  • Patellofemoral Pain Syndrome
  • Osgood-Schlatter
  • Sinding-Larsen-Johannson
• Idiopathic
  • Blount's Disease

Special Considerations

Referred Pain from the Hip

The hip joint should always be examined first before the clinician assesses the knee. Pain from the hip, like in the adult, is referred usually to the medial joint line of the knee.

Restricted abduction in flexion indicates hip pathology until proven otherwise.

Two common hip pathologies to consider are:

1. Perthes disease (age 6-10) 
2. Slipped femoral epiphysis (age 10-14)

Suspected Growth Plate Fractures

It should always be remembered trauma resulting in ligament injuries in adults might in children result in bone or growth plate fractures. Isolated knee ligament injury is rare in children younger than 14 years as the ligaments are stronger than the physes.

Also remember even if the initial X ray is normal and the child either limps or is unable to weight bear and the physis is tender a fracture should be suspected and the child treated as such.

Tumour

Benign and malignant (primary and metastatic) tumours do occur about the knee. Local trauma often focuses attention on an area in which a tumour is subsequently diagnosed.

Tumours can present with pain, swelling or pathological fracture and one should always like in the adult bear this diagnosis in mind when assessing knee pain especially if the symptoms and signs are atypical.

Infection

The most common organisms responsible for osteomyelitis are Staphylococcus aureus, Streptococci, E Coli, Proteus and Pseudomonas. Often no primary infective site is found. The most common presentation is pain, warmth and tenderness over the affected part and an unwillingness to move the adjacent joint. It is possible to get an effusion in the neighbouring knee joint however the growth plate usually prevents infective spread into the joint.

All patients should be checked for diabetes or impaired immune function.

Inflammatory Arthritis

Juvenile Idiopathic Arthritis (JIA) should also be ruled out.