Extraarticular Resection Of Malignant Tumor Around Knee Joint And Its Related Anatomy And Biomechanics Of Patellar Tendon

Primary bone tumors mostly occur at the knee joints. Tumor resection and custom-made prosthesis are main therapies for malignant and invasive bone tumors. Because the cartilage, epiphyseal plate and capsule of the knee joint can form effective barriers against tumor invasion, the knee joint itself is rarely directly involved. There are several reasons for the contamination and invasion of the knee joint by tumors:Improper biopsy sites; Tumors grow into the knee joint through the anterior cruciate ligament; Pathological fracture and tumors invade into the knee joint directly. When the sarcoma involved or contaminated the joint, we should resect sarcoma extraarticularly and completely. In spite of the advancements in the limb salvage techniques; there are a lot of difficulties in reconstructing the extensor mechanism. So patients with sarcoma involving the knee joint were treated by amputation and rotation plasticity. Extraarticular sarcoma resection and prosthesis reconstruction has become a priority surgery now because of the limited lower limbs functionalities of the previous surgery. The intact extraarticular sarcoma resection and the reconstruction of the extensor mechanism are the most important and also the most difficult parts of the surgery. In this paper, we reviewed the applied anatomy of the knee joint, the diagnosis of the sarcoma, the indications of the surgery, the surgical technique and mechanical characteristics of patellar ligament after surgery. Observe the attachment of the articular capsule and the synovial capsule which is communicant with the joint cavity (the infrapatellar fat pad and the deep infrapatellar bursa are primary concerns). Notice the location and volume of the deep infrapatellar bursa by anatomy and see whether it is communicant with the joint cavity. Observe synovial capsule and the deep infrapatellar bursa which is communicant with the joint cavity by joint cavity radiography and CT 3-dimentional reconstruction. To depict the indications of the surgery and how to define the involvement of joint by the sarcoma and reviewed all the surgery methods when the knee joint is invaded. From the previous results, we can come to the conclusions that:1. Synovial bursa communicant with the knee joint cavity are suprapatellar bursa, bursa of semimembranosus, and Popliteus capsule.2. The deep infrapatellar bursa is located beneath Patellar ligament, no evidence of communication with the joint cavity was found. But there is still some other data show the communication of the deep infrapatellar bursa with knee joint cavity, so deep infrapatellar bursa radiography is recommended to decide the method of surgery.3. The infrapatellar fat pad is located partially inside the joint, and partially outside the joint. The infrapatellar fat pad should be extra-articular resected when the deep infrapatellar bursa is not interlinked with the knee joint cavity, whereas the patellar tendon should be cut sagittally in order to achieve complete tumor resection.4. Compared with the transknee tumor resection, extraarticular sarcoma resection has satisfying oncological and functional results, but increase the incidence of postoperative complications.5.Biomechanical tests show that the sagittal cut through the patellar tendon can meet the daily needs of walking.