Surgical therapy of benign and low-grade malignant intramedullary chondroid lesions of the distal femur: intralesional resection and bone cement filling with or without osteosynthesis.

Surgical treatment of benign and low-grade malignant intramedullary chondroid lesions at the distal femur is not well analyzed compared to higher-grade chondrosarcomas. Localization at the distal femur offers high biomechanical risks requiring sophisticated treatment strategy, but scientific guidelines are missing. We therefore wanted to analyze a series of equally treated patients with intralesional resection and bone cement filling with and without additional osteosynthesis. Twenty-two consecutive patients could be included with intralesional excision and filling with polymethylmethacrylate bone cement alone (n = 10) or with compound bone cement osteosynthesis using a locking compression plate (n = 12). Clinical and radiological outcome was retrospectively evaluated including tumor recurrences, complications, satisfaction, pain, and function. Mean follow-up was 55 months (range 7-159 months). Complication rate was generally high with lesion-associated fractures both in the osteosynthesis group (n = 2) and in the non-osteosynthesis group (n = 2). All fractures occurred in lesions that reached the diaphysis. No fractures were found in meta-epiphyseal lesions. No tumor recurrence was found until final follow-up. Clinical outcome was good to excellent for both groups, but patients with additional osteosynthesis had significantly longer surgery time, more blood loss, longer postoperative stay in the hospital, more complications, more pain, less satisfaction, and worse functional outcome. Intralesional resection strategy was oncologically safe without local recurrences but revealed high risk of biomechanical complications if the lesion reached the diaphysis with an equal fracture rate no matter whether osteosynthesis was used or not. Additional osteosynthesis significantly worsened final clinical outcome and had more overall complications. This study may help guide surgeons to avoid overtreatment with additional osteosynthesis after curettage and bone cement filling of intramedullary lesions of the distal femur. Meta-epiphyseal lesions will need additional osteosynthesis rarely, contrary to diaphyseal lesions with considerable cortical thinning.