Rare diseases · Sign or symptom
Knee flexion contracture
HP:0006380
What it means
A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively.
Rare diseases that can present with this35
Very common80–99%
4Common30–79%
11- Autosomal recessive spastic paraplegia type 43
- Congenital patella dislocation
- Infantile-onset X-linked spinal muscular atrophy
- Isolated tibial hemimelia
- Multiple epiphyseal dysplasia, Lowry type
- Neurogenic arthrogryposis multiplex congenita
- Recessive intellectual disability-motor dysfunction-multiple joint contractures syndrome
- Say-Barber-Miller syndrome
- Stüve-Wiedemann syndrome
- Ullrich congenital muscular dystrophy
- X-linked microcephaly-growth retardation-prognathism-cryptorchidism syndrome
Sometimes5–29%
19- Autosomal recessive spastic paraplegia type 62
- Congenital fiber-type disproportion myopathy
- Congenital myasthenic syndrome with glycosylation defect
- DPM1-CDG
- Hypotonia-speech impairment-severe cognitive delay syndrome
- Isolated succinate-CoQ reductase deficiency
- Kyphoscoliosis-lateral tongue atrophy-hereditary spastic paraplegia syndrome
- Microcephalic cortical malformations-short stature due to RTTN deficiency
and 11 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Flexion contracture of knees · Flexion contractures at both knees · Flexion contractures of knees · Flexion deformity of the knee · Inability to straighten knee · Knee flexion contractures · Knee flexion deformity
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.