Complex Primary Total Knee Arthroplasty in a Patient with Achondroplasia, Osteoarthritis, and Severe Coronal Instability.

Genu varum in patients with achondroplasia is common and is often exacerbated by the associated generalized ligamentous laxity. Despite this, development of knee osteoarthritis is rare. There are only a few previously published case reports of total knee arthroplasty in this population. We present 2-year follow-up of a patient with achondroplasia who underwent staged bilateral primary total knee arthroplasties using hinged components. Technical considerations and careful preoperative planning are required in patients with achondroplasia given their small skeletal stature, metaphyseal deformities, and ligamentous laxity.