Total Femur Replacement for Treatment of Chondrosarcoma Involving the Entire Femur

Introduction

Tumors that involve a large segment of the entire femur are difficult to treat without performing a hip disarticulation. The Van Nes turnabout procedure allows the surgeon to resect ⅔ or more of the distal femur along with the vessels and bring the tibia up with the foot in place but rotated 180° to serve as a surrogate knee1, 2. This procedure, although well documented, is frequently used to treat children or young adults but not older individuals. Total femoral resection and metallic prosthesis replacement has been the option preferred by some surgeons since it was first reported by Buchman in 19653. A number of authors have reported the survival and functional outcomes for large numbers of metallic system procedures4, 5, 6, 7, 8, 9, 10; however, these procedures entail some difficulties including the complexity of the surgery and some problems with metallic prostheses.

Case Presentation and Surgical Procedure

We here present a female patient aged 69 years who was admitted to our hospital with left thigh pain of 6 month duration that had been getting worse over the previous 1 month. She had unbearable pain at night and could not walk without assistance. On physical examination she had normal hip joint flexion, slightly limited knee joint flexion, slight muscle weakness in the left lower limb and a soft tissue mass in the distal thigh. X‐ray examination showed an extensive lesion with flocculent calcification in the medullary cavity of the femur and a soft tissue tumor in the distal thigh. MRI showed clear boundary in the soft tissue and no invasion of blood vessels and nerves. No other lesion was found except the femur in the emission computed tomography of bone scan. Pathological examination of a needle biopsy resulted in a diagnosis of chondrosarcoma.

The patient underwent routine preoperative condition assessment and was considered fit for surgery. Two incisions, namely a lateral approach to the hip and a medial parapatellar approach were used to perform the procedure. Antibiotics were administered 30 min before surgery and continued for one week postoperatively. Multimodality analgesia was used in this patient, comprising preoperative analgesia with 400 mg celecoxib the night before surgery, a disposable perfusion pump for 48 hours analgesia after surgery and non‐steroidal anti‐inflammatory drugs (NSAIDs) for a week after removal of the pump. Anti‐deep vein thrombosis (DVT) treatment was started on the first postoperative day; this included physical methods (foot pump, muscle compression) and drugs (low molecular weight heparin). Isometric quadriceps exercises started on the first postoperative day and the patient began weight bearing in the third postoperative week.

Discussion

The main advantage of total femoral replacement over other methods of treatment such as hip disarticulation, hemipelvectomy or isolated hip or knee revision is that it provides immediate stability, enabling early mobilization. Total femoral replacement should be performed only for tumors involving the entire femur that can be resected en bloc. As for tumor control, the same principles apply with total femoral replacement as with hip disarticulation.

Preoperative Measurement and Prosthesis Design

Preoperative assessment requires measurement of the prosthesis length on an anteroposterior plain full‐length radiograph of both lower extremities. The prosthesis design includes an artificial femoral head, metallic femoral shaft and knee joint prosthesis; different size modules of these prostheses are needed. Detailed information about the tumor can be provided by MRI. In our case, a sagittal MRI showed abnormalities within the entire bone and a soft tissue mass over the distal femur, whereas an axial MRI showed that the soft tissue mass had clear boundaries, which helped the surgeon to achieve a correct tumor border.

Surgical Techniques

Total femoral replacement is generally thought to be a complex procedure because it is not often performed. With our patient two incisions were made to obtain exposure, one a lateral approach to the hip and the other a medial parapatellar approach. The lateral approach to the hip is widely used for total hip replacement and the medial parapatellar approach for total knee replacement; thus, these two incisions are much more familiar to most surgeons than a single lateral incision for the entire length of the thigh. The muscles that attach to the proximal femoral periosteum can be resected via the lateral approach to the hip whereas those to the middle and distal femur can be resected via the medial parapatellar approach. Through these two incisions, a shared filed of surgery can be created under the skin. Another consideration is how to achieve an en bloc resection of a tumor. In our patient, an anterior approach provided good access to the soft tissue mass, which was in the distal femur. The posterior part of the tumor was exposed after resection of knee joint ligaments and freeing of the distal femur. The procedure for installing the prosthesis is similar to that for a hinged knee prosthesis; the tightness of muscle determines the appropriate length of prosthesis. Provided the knee component of the prosthesis is installed first, followed by the femoral head component, installation of the prosthesis can readily be achieved. Restoration of hip stability is a very important aspect of this surgery. To avoid hip dislocation, the hip capsule, external rotators and tensor fasciae latae must be sutured; additionally, hip functional exercise should delayed. Stapling needles are recommended for skin closure and the drainage should be continued for a week because of the use of low molecular weight heparin.

Postoperative Treatment

Postoperative use of antibiotics and analgesics and prevention of DVT are very important. Because infection is a catastrophic complication, in addition to practicing strict asepsis during surgery, administration of preoperative antibiotics 30 min before surgery and continuing them for one week postoperatively are critical. Multimodality analgesia, including preoperative analgesia, intraoperative incision block therapy and postoperative NSAIDs can be used. Early physical and drug therapy reduces the incidence of DVT.

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Supporting information

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