Background <p>Melorheostosis is a rare disease with a classical radiological performance appearing as the sign of skeletal hyperostosis like dripping wax flowing down from candle. The pathological bone hyperostosis and soft tissue fibrosis frequently resulted in intolerable pain and functional loss. Due to the low incidence of 0.9 per million, the management for the disease is rarely reported. In this report, we introduce a typical case of melorheostosis affecting both knee and ankle and share the management and outcome for this patient.</p> Case presentation <p>A 52-year-old female patient presented with walking morbidity due to severe restriction of range of motion (ROM) in left knee and ankle. Clinical examination revealed a 40° flexion contracture with fully restricted ROM in left knee and 10°-40° plantar flexion ROM in left ankle. Radiological examination showed sclerotic cortical hyperostosis in her entire left limb. The patient was diagnosed with melorheostosis. The unusual disease affected both her knee and ankle and the patellofemoral joint was filled with great masses at medial and lateral sides of patella, which were rarely seen in reports before. The patient underwent total knee arthroplasty combined with an uncommon V-Y quadricepsplasty due to the failure of the common parapatellar approach for surgical exposure. At the latest 2-year follow-up, the patient obtained a remarkable decrease in preoperative pains, and large functional improvements without permanent extension lag. No event was reported on any recurrence of soft-tissue contractures or severe TKA-related complications during the follow-up.</p> Conclusions <p>In this case with two years of follow-up, we shared the insight into the management of this rare condition affecting both the knee and ankle joints and initially reported the use of V-Y quadricepsplasty and the rehabilitation in knee arthroplasty for melorheostosis.</p>