Three-dimensional-printed custom-made patellar endoprosthesis for recurrent giant cell tumor of the patella:A case report and review of the literature

BACKGROUND Giant cell tumor(GCT)is a benign lesion and rarely involves the patella.This disease is characterized by a relatively high recurrence rate after primary treatment.En bloc resection has been a predominant option for recurrent GCT.However,total patellectomy can lead to disruption of the knee.Therefore,exploration of functional reconstruction of the extensor mechanism is worthwhile.CASE SUMMARY A 54-year-old woman presented with right knee pain and swelling,and was diagnosed as having a GCT in the patella following curettage and autograft.Medical imaging revealed a lytic and expanded lesion involving the whole patella with focal cortical breaches and pathological fracture.Based on the combination of histological,radiological,and clinical features,a diagnosis of recurrent GCT in the patella was made(Campanacci grade III).After a multidisciplinary team discussion,three-dimensional(3D)-printed custom-made patellar endoprosthesis was performed following en bloc resection for reconstructing the extensor mechanism.The patient was followed for 35 mo postoperatively.No evidence of local recurrence,pulmonary metastasis,or osteoarthritis of the right knee was observed.The active flexion arc was 0°-120°,and no extension lag was detected.A favorable patellar tracking and height(Insall-Salvati ratio 0.93)were detected by radiography.CONCLUSION We depict a case of a GCT at the right patella,which was successfully treated by patellectomy and 3D-printed custom-made endoprosthetic replacement.The patella normal reconstruction,the precise-fit articular design,and gastrocnemius flap augmentation could lead to satisfactory knee function and a low rate of complications in the short-term follow-up.

Long-term survival in a patient with Hutchinson-Gilford progeria syndrome and osteosarcoma:A case report

BACKGROUND Hutchinson-Gilford progeria syndrome(HGPS)is an extremely rare disease characterized by the rapid appearance of aging with an onset in childhood.Serious cardiovascular complications can be life-threatening events for affected patients and the cause of early death.Herein we report a HGPS patient with osteosarcoma hat was successfully managed and is alive 13 years after the diagnosis.This is the first report describing the detailed surgical procedure and long-term follow-up of osteosarcoma in a patient with HGPS.CASE SUMMARY The patient was diagnosed with HGPS at 5 years of age with typical features and was referred to our department with a suspected bone tumor of the left proximal tibia at the age of 18.Open biopsy of the tibial bone tumor revealed a conventional fibroblastic osteosarcoma.We have developed and performed a freezing technique using liquid nitrogen for tumor reconstruction.This technique overcame the small size of the tibia for megaprosthesis and avoided amputation and limb salvage was achieved 13 years post-operatively.Although the patient had a number of surgical site complications,such as wound dehiscence,and superficial and deep infections due to vulnerable skin in HGPS,no recurrence or metastases were detected for 13 years,and she walks assisted by crutches.Her general health was good at the latest follow-up at 31 years of age.CONCLUSION A HGPS patient with osteosarcoma was successfully managed and she was alive 13 years after the diagnosis.