Session VII - Tibia

The Use of Hybrid Fixators in Proximal Tibia Fractures

Roberto Varsalona, MD; Bruce H. Ziran, MD; S. Avondo, MD; Q. Mollica, MD; University of Catagnia, Sicily, Italy; and University of Pittsburgh, Department of Orthopaedics, Pittsburgh, Pennsylvania, USA

Purpose: Severe proximal tibia fractures, which include intra- and extraarticular fractures with metaphyseal-diaphyseal dissociation, pose a difficult treatment problem for the surgeon with significant complication rates. Use of external or internal fixation remains the main methods of treatment, with strong advocates for each method. Although there are pros and cons to both methods, we have found that accurate reduction (closed or open) with hybrid fixation has provided the best results. The purpose of this study was to report experience with a series of consecutive severe proximal tibial fractures.

Methods: We treated 118 cases of proximal tibia fracture, of which 52 were treated with hybrid external fixation as part of a protocol that used a consistent approach and method of hybrid external fixation. Inclusion criteria for hybrid treatment (as opposed to closed treatment) were severe soft tissue injury, intraarticular displacement, and unstable fracture pattern involvement (AO A2, A3, and C patterns). Patients were treated on a fracture table with calcaneal traction. Reduction was achieved with ligamentotaxis and percutaneous clamps when possible. If necessary, limited incisions were used to elevate depressed fragments and place bone grafts. Articular congruity was assessed with fluoroscopy or arthroscopy or both. Fixation of the condyles was achieved with cannulated screws or beaded olive wires or both. The distal frame consisted of a multi-clamp or a single clamp and used three to four 5-mm half pins. The distal frame was connected to the ring with adjustable components (rods or a monolateral external fixator). A standard postoperative management protocol was followed involving immediate range of motion, weight-bearing as tolerated, and pin care. The management of the rigidity of the external fixations began with three to four rods, and rods were progressively removed or replaced or both with a dynamic axial monotube assembly. Clinical and radiographic evaluation was performed at routine intervals. In addition to routine demographic data, objective data collected included healing, deformity, complications, and motion. Patients were also evaluated with an SF-36 questionnaire 12 months after healing.

Results: There were 52 patients with an average age of 42 years (range,17 to 78) with a mean follow-up of 24 months (range, 12 to 30). There were 40 men and 12 women, who sustained 31 fractures of the right leg and 21 fractures of the left leg. The mechanisms of injury were a motorcycle accident (18 patients), a pedestrian-motor-vehicle accident (13 patients), a motor-vehicle accident (9 patients), a fall from a height (9 patients), being struck by an object (2 patients), and sports activity (1 patient). There were 13 open fractures and 3 A2, 3 A3, 16 C1, 12 C2, and 18 C3 injuries. Seven patients had other major fractures of the ipsi- or contralateral limb, involving the femur, the shaft of the tibia, the ankle, the calcaneus, the femur, and the distal part of the other tibia. Two patients had upper limb fractures (one humeral and one wrist fracture). Two patients had a rupture of the patellar ligament, necessitating repair. All proximal tibia fractures healed without additional procedures. All patients were radiographically and clinically healed by 24 weeks. Most patients demonstrated healing by 16 weeks. Full weightbearing was established at a mean of 8.4 weeks (range, 5 to 10). Forty-six patients (88%) achieved full extension, and the remaining 6 (11%) had an extension deficit of less than 10°. Three patients (5%) had less than 90° of flexion, 27 had flexion beyond 100°, and 22 patients were able to flex beyond 110°. Thigh atrophy of more than 1 cm was noted in only one patient. The SF-36 profiles were health state/rate, daily activity, work activity, emotional problems, and pain. There were no intraoperative injuries to nerves or major vessels. Postoperative complications included superficial pin tract infections in 15 K-wires or pins, all of which resolved with local pin care and a short course of oral antibiotics. One patient had a deep venous thrombosis. None required removal of the fixator before healing of the fracture. No patient developed osteomyelitis or septic arthritis. Accuracy of reduction was 0 to 1mm in 28 patients, 2 to 3 mm in 19 patients, 4 to 5 mm in 4 patients, and more than 5 mm in 1 patient. Only 5 (10%) of the 52 patients had an angular malunion greater than 6°. One patient had a loss of reduction during treatment with hybrid external fixation. Four patients developed a mild varus deformity, when compared with the contralateral uninvolved knee. There were no valgus malunions and no nonunions. Final malalignment of the tibiofemoral axis did not exceeded 3° on full-length weight-bearing radiographs. Radiographic and clinical evidence of degenerative arthritis was seen in 12 of 52 patients (23%) 18 months after healing. Ten of these patients had C3 and 2 had C2 fracture patterns. Six of these patients were those that had angular malunions noted above. The remaining six patients had reductions to within 3 mm.

Discussion: The benefit of restoration of normal anatomic structure by means of an open procedure must be weighed against the risk of infection, soft tissue complications, and malunion. Traditional open reduction and plating carries a significant incidence of wound complications and unsatisfactory results. Complex proximal tibial fractures sometimes require two plates for optimal fixation, which can result in an unacceptably high rate of infection. A hybrid fixator can maintain length and alignment while spanning a zone of comminution in the metaphyseal-diaphyseal region. It allows for access to any open wounds or compromised soft tissue. The device allows secondary correction of angular or rotational deformities when necessary and also early weightbearing and range of motion of the knee and ankle. We found that in a fairly large series of patients with medium to long-term follow up, the hybrid fixator performed very well from a technical standpoint. The development of radiographic arthrosis seemed to correlate more with the initial articular injury and alignment than to the nature of treatment. Intuitively, the quality of reduction will obviously impact the outcome but we were able to achieve satisfactory reductions in the majority of cases. We found that patients were allowed to bear weight and regain excellent knee motion. Our regimen of beginning with absolute construct rigidity in the first 2 to 6 weeks of healing, followed by gradually decreasing the stiffness of the frame (rod removal and conversion to monotube dynamic tube), allowed for progressively increased load-sharing with the developing fracture callous. In summary, we found that hybrid external fixation is a good alternative method for treatment of meta- or epiphyseal fractures or both. The technique and postoperative management we describe respects soft tissue and bone and allows for early articular mobilization.