OTA 1997 Posters - Tibia Fractures

Treatment of Segmental Defects of the Tibia with the Use of Cylindrical Titanium Mesh

Jose A. Cobos, MD, Ronald W. Lindsey, MD

Houston, Texas, USA

Purpose: We describe a new technique in which a titanium cage filled with cancellous bone is used to bridge a segmental defect of the tibia in an acute or sub-acute trauma situation. The cage is placed with the dual purpose of maintaining the bone length and providing structural support for early weight bearing on the affected extremity while the bone graft is incorporating. The stability is augmented by the placement of an intramedullary rod.

Methods: Surgical Technique: After adequate preparation of the extremity is accomplished, the wound is copiously irrigated and debrided. The bone edges are identified and the segmental defect is measured. A twenty-six by thirty-three millimeter meshed titanium cage is cut one to two centimeters longer than the defect and reinforced at both ends with standard rings. After correct fit the mesh is passed to the back table where it is packed tightly with cancellous bone. A guide wire is inserted through the center of the cage and with reamers, a ten millimeter canal is created. An approach for antegrade tibia nailing is made. A guide wire is passed along the medullary canal of the proximal tibia fragment, the titanium mesh is inserted in the defect and the guide wire passed through its center and into the distal fragment. The intramedullary canal is then reamed to an eleven millimeter diameter. After the length of the bone is measured, a ten millimeter titanium intramedullary nail is inserted and locked. Bone graft is applied around the proximal and distal bonemesh areas and in the posterior aspect of the mesh. After irrigation, the proximal and distal surgical wounds are closed. The soft tissue defect is then addressed by the plastic surgeon. After the coverage is completed the extremity is immobilized with a short leg splint. If a soft tissue defect is no longer present, an incision is made in the anterior aspect of the bone defect area and after identification of the bone ends, debridement of granulation tissue and opening of the intramedullary canal is carried out. The same steps for measuring, preparation of the mesh and intramedullary guide insertion are followed but the wound is closed before the reaming of the intramedullary canal takes place, continuing with the rest of the steps in a "blind" fashion.

Post-operative care: The patient is maintained with the extremity elevated the day of surgery. Intravenous antibiotics are given the first forty-eight hours. The patient is gait trained using crutches or walker, starting with toe touch weight bearing status in the affected extremity. Once the plastic surgery team uncovers the wound and the skin graft has taken, the patient is fitted to a short leg walking cast and the weight bearing status is advanced to partial weight bearing. If no wound coverage was needed, the wound is inspected on postoperative day two and the patient is placed in a short leg walking cast. The patient is discharged once gait training is completed. After discharge the patient is followed as an outpatient and routine roentgenograms to check the alignment as well as the status of the bone graft are performed. The patient is advanced to protected full weight bearing at twelve weeks after surgery.

Results: Two patients have been treated with this technique. They had IIIB open fractures treated initially elsewhere with early debridement and external fixation. One patient had his wound closed during the main procedure, and the other before referral for main procedure. The procedures were performed in less than two hours. Follow-up is of six and two months, respectively (case presentations). Both patients are ambulatory with protective weight bearing wearing a boot and a short leg cast respectively. Hospital stay after the main procedure was of six days (patient that required flap coverage) and three days (patient with primary closure). They are active and at last follow-up, have not developed local or systemic complications.

Conclusion: The use of mesh titanium cages as structural support in segmental long bone defects, packed with bone graft, provides another alternative of treatment for this complex problem.

Discussion: Segmental defects of long bones are a common occurrence in orthopedic trauma. In the past, amputation of the extremity was common. Bone transport technique has been used to treat large defects but many disadvantages exist with this technique such as the time involved to achieve its goal and the detrimental effect in the patient's activities of daily living. Complications, such as infection, are common and many patients require revisions of the device. Bone transport technique also requires an experienced surgeon, a reliable patient and significant amount of time and resources.

Meshed titanium cages are used as structural support in spine surgery. The cage is filled with cancellous bone or cement in cases of trauma or tumors. These cylinders have the structural strength to tolerate the body weight maintaining the space without collapse while the bone graft is incorporated. The use of these cages in segmental defects has never been described. They provide immediate continuity, maintain the bone graft contained within the defect, allow early weight bearing of the extremity. The placement requires a single procedure, avoiding repeated disruption of the soft tissue envelope.