Review Question - QID 3495

While intra-articular extension of osteosarcoma is a rare presentation, understanding of the various treatment options available is crucial for the treating surgeon. Often joint contamination occurs secondary to a previous surgical procedure when a malignant neoplasm isn't considered in the differential diagnosis. While limb salvage may be possible with joint contamination, optimization of function and limitation of the number of future surgical procedures needs to be considered. Rotationplasty (Illustrations A and B) offers the treating surgeon the ability to perform a safe and negative margin resection while at the same time maximizing patient function and limiting the number of future re-operations.

Damron et al review the various joint-related tumors which mimic sports-related injuries in their instructional course lecture. They suggest that appropriate preoperative imaging and consideration of malignant conditions in the differential diagnosis of any suspicious condition will increase the chances that the treating surgeon correctly identifies the neoplasm and avoids a procedure which compromises limb-salvage.

Quan et al retrospectively reviewed 27 cases of peri-articular osteosarcoma, specifically looking for intra-articular involvement. They suggest that intra-articular involvement of osteosarcoma is very rare as articular cartilage serves as a good boundary to tumor expansion. Joint contamination from an incorrect surgical procedure is a much more likely cause of intra-articular extension.

Incorrect answers
1) Through knee amputation - with joint contamination, a through knee amputation would not provide an appropriate negative margin resection and therefore contaminate the distal resection margin with tumor
2) Above knee amputation - while this would provide a safe resection level, the level of function would not be as great as with a rotationplasty
4 & 5) Both of these options would be available for limb salvage, however they would not result in as high a level of function as a rotationplasty. In addition these procedures would likely require many subsequent operations given the higher rates of complication and the need for future prosthetic lengthening/exchange.