Modified porous tantalum rod technique for the treatment of femoral head osteonecrosis

AIM: To study a modified porous tantalum technique for the treatment of osteonecrosis of the femoral head.METHODS: The porous tantalum rod was combined with endoscopy,curettage,autologous bone grafting and use of bone marrow aspirates from iliac crest aspiration in 49 patients(58 hips) with a mean age of 38 years.The majority of the patients had idiopathic osteonecrosis,followed by corticosteroid-induced osteonecrosis.Thirtyeight hips were of Steinberg stage Ⅱ disease and 20 hips were of stage Ⅲ disease.Patients were followed for 5 years and were evaluated clinically with the Merle D'Aubigne and Postel score and radiologically.The primary outcome of the study was survival based on the conversion to total hip arthroplasty(THA).Secondary outcomes included deterioration of the osteonecrosis to a higher disease stage at 5 years compared to the preoperative period and identification of factors that were associated with survival.The Kaplan-Meier survival analysis was performed to evaluate the survivorship ofthe prosthesis,and the Fisher exact test was performed to test associations between various parameters with survival.RESULTS: No patient developed any serious intraoperative or postoperative complication including implant loosening or migration and donor site morbidity.During the 5-year follow up,1 patient died,7 patients had disease progression and 4 hips were converted to THA.The 5-year survival based on conversion to THA was 93.1% and the respective rate based on disease progression was 87.9%.Stage Ⅱ disease was associated with statistically significant better survival rates compared to stage Ⅲ disease(P = 0.04).The comparison between idiopathic and non-idiopathic osteonecrosis and between steroid-induced and non-steroid-induced osteonecrosis did not showed any statistically significant difference in survival rates.The clinical evaluation revealed statistically significantly improved Merle d'Aubigne scores at 12 mo postoperatively compared to the preoperative period(P < 0.001).The mean preoperative Merle d'Aubigne score was 13.0(SD: 1.8).The respective score at 12 mo improved to 17.0(SD: 2.0).The 12-mo mean score was retained at 5 years.CONCLUSION: The modified porous tantalum rod technique presented here showed encouraging outcomes.The survival rates based on conversion to THA are the lowest reported in the published literature.

Low-grade central osteosarcoma of distal femur, resembling fibrous dysplasia

We report a case of a 32 year-old male, admitted for a lytic lesion of the distal femur. One month after the first X-ray, clinical and imaging deterioration was evident. Open biopsy revealed fibrous dysplasia. Three months later, the lytic lesion had spread to the whole distal third of the femur reaching the articular cartilage. The malignant clinical and imaging features necessitated excision of the lesion and reconstruction with a custom-made total knee arthroplasty. Intraoperatively, no obvious soft tissue infiltration was evident. Nevertheless, an excision of the distal 15.5 cm of the femur including 3.0 cm of the surrounding muscles was finally performed. The histological examination of the excised specimen revealed central low-grade osteosarcoma. Based on the morphological features of the excised tumor, allied to the clinical findings, the diagnosis of low-grade central osteosarcoma was finally made although characters of a fibrous dysplasia were apparent. Central low-grade osteosarcoma is a rare, well-differentiated sub-type of osteosarcoma, with clinical, imaging, and histological features similar to benign tumours. Thus, initial misdiagnosis is usual with the condition commonly mistaken for fibrous dysplasia. Central low-grade osteosarcoma is usually treated with surgery alone, with rare cases of distal metastases. However, regional recurrence is quite frequent after close margin excision.