Fig. 25.1
Fifty-four year-old male with metastatic non-small cell lung adenocarcinoma. MRI demonstrating focal area in posterolateral tibial plateau, with involvement of the tibial articular cartilage
Fig. 25.2
Metastatic lesion treated with extended curettage, local adjuvants, and cementation of the remaining defect. The patient had complete relief of symptoms immediately
With regard to distal tibial lesions that are non-articular, many surgeons choose to treat these with extended curettage and stabilization with plates or intramedullary nails or a combination of the two given the lack of stability provided by intramedullary nails alone in some scenarios. Distal tibial megaprosthetics can be used in rare circumstances, though with limited soft tissue coverage available and difficulties with wound healing in patients undergoing adjuvant systemic and local treatments, complications can be significant. In extreme cases, with severe osseous destruction and no reasonable reconstruction, a below knee amputation can be utilized. In some cases, a retrograde fusion-type nail can be used in order to negate the need for below knee amputation if there is adequate bone above and below the metastatic lesion to maintain stability for the remainder of the patient’s life, without the goal of actually obtaining an osseous union.
Patients who undergo below knee amputation can expect a significant decrease in pain with weight bearing [19, 20]. However even inpatients who are healthy and not immune-compromised, there is a very real likelihood of recovering fully for 2–4 months before reasonably comfortable weight bearing with a well fit prosthesis is possible. This can be a major deterrent to this historically successful procedure, given that this recovery may be longer than the expected lifespan of the patient. The long-term benefits seen in patients with mangled feet are mitigated in patients with limited life expectancy given the short-term problems with healing, and prosthetic fit in immune-compromised patients. In most patients at this stage in their disease, and with limited life expectancy, the possibility of prosthetic use may be significantly limited, and amputation likely leaves the patient dependent on a wheelchair.
Pathologic Fractures of the Tibia
When a fracture has been realized, and is no longer simply a lesion of the tibia at risk of fracture, the treatment algorithm is much like that of an impending fracture, and surgical intervention is usually warranted. Rigid internal fixation is paramount given the high likelihood of delayed and nonunion in the tibia given its inferior blood supply, relatively thin soft tissue envelope, and relatively smaller size when compared to its more proximal boney counterparts. For this reason, treating pathologic fractures of the tibia is to control pain and mobility rather than surgery with the goal of osseous union. Surgery is usually the treatment of choice in the case where the fracture causes pain and immobility in a patient who may otherwise benefit from pain control and mobility with surgical intervention. Clearly the challenge of obtaining osteosyntheses through diseased bone in the tibia is, historically, a loosing battle, though understanding reconstructive techniques that can mimic union for the remainder of the patient’s lifespan can accomplish the goal at hand.
When possible, locked intramedullary, load sharing devices are superior in that they allow patients to bear immediate weight and remain mobile in the late stages of disease. The use of assistive devices in these patients may also be compromised given the fact that they may have other, more proximal sites of disease, and disease in their upper extremities. Also, the use of intramedullary devices can diminish the number of complications seen with plate fixation requiring larger incisions and longer time to adjuvant radiation, and inadvertent weight bearing through load bearing devices. Figure 25.3 demonstrates a locked, intramedullary nail for a patient with a non-displaced, insufficiency-type fracture through metastatic lung cancer. The patient was able to weight bear immediately on this, and started radiation 10 days postoperatively, given the very small incisions, and low risk of dehiscence and wound healing issues seen with plate and screw fixation. Pain was reduced immediately. Three months postoperatively, the patient continued to improve with boney remodeling. In this case, given microvascular disease and significant venous stasis, no curettage was performed given the risk associated with the soft issue envelope of the proximal tibia. Given the multiple proximal screw options, and the ability to span the entire bone with a load sharing device, it was considered to be a reasonable option and one that would more readily return him to his desired, normal activity.
