Intra-articular tumours of the soft tissue inside the knee joint may typically cause swelling, pain and mechanical symptoms like a "catching" sensation. Dr Marais can remove most of these tumors with an arthroscopic procedure. This is a much less invasive technique and the traditional open surgery and will allow for a quicker recovery time and less pain post surgery. He may make numerous small incisions in the knee through which he will insert surgical tools to remove the intra-articular tumour. Part of this tumour is send for histological analysis by a pathologist.