Thanks for writing in.
Ataxic cerebral palsy is caused by damage to the cerebellum, which is controls balance and coordinates the actions for different groups of muscles. It usually affects all four limbs and also the trunk. The muscle tone is poor, i.e. there is hypotonia. The characteristic symptom of ataxic cerebral palsy is intention tremor, which worsens while trying to attempt any voluntary movements, such as writing or buttoning a shirt.
Patients with ataxic cerebral palsy will usually have a broad-based gait, i.e. they walk with their feet unusually far apart. They usually look very unsteady due to low muscle tone as the body has to constantly try to counter-balance itself. Also they have poor spatial judgement for the distance between their legs and the ground. This leads to thumping.
The postural defects and resulting joint instability may lead to increased wear and tear of the weight bearing joints in the body. Hence, there might be increased risk of development of osteoarthritis. However you should take the opinion of an orthopedic doctor and a neurologist.