Differential Diagnosis for Snapping Knee in Infant Child
Single Most Likely Diagnosis
- Nursemaid's knee (Patellar subluxation): This condition is a common cause of a snapping or clicking sound in the knee of an infant child, usually due to a subluxation of the patella. It often occurs when the child is lifted or moved, causing the patella to move out of its normal position.
Other Likely Diagnoses
- Discoid meniscus: A congenital anomaly where the meniscus is thicker and more disc-like, which can cause a snapping sound as it moves.
- Meniscal tear: Although less common in infants, a meniscal tear can cause a snapping or clicking sound in the knee.
- Patellofemoral pain syndrome: This condition can cause a snapping or grinding sensation in the knee, especially when the child moves their knee.
Do Not Miss Diagnoses
- Septic arthritis: Although rare, septic arthritis is a serious condition that requires prompt treatment. It can cause pain, swelling, and limited mobility in the affected joint, and may be accompanied by a snapping sound if the joint is moved.
- Osteomyelitis: An infection of the bone that can cause pain, swelling, and limited mobility, and may be accompanied by a snapping sound if the affected bone is moved.
- Tumor or cyst: A rare but serious condition that can cause a snapping sound if the tumor or cyst is located near a joint or tendon.
Rare Diagnoses
- Chondromalacia patellae: A condition where the cartilage on the underside of the patella becomes soft and fragile, which can cause a snapping or grinding sensation in the knee.
- Synovial chondromatosis: A rare condition where cartilage grows in the synovial membrane of the joint, which can cause a snapping or clicking sound.
- Congenital knee dislocation: A rare congenital condition where the knee is dislocated, which can cause a snapping or clicking sound as the joint moves.