The objective of this study was to evaluate the efficacy and stability of bioresorbable plates in condylar fractures in adults. Twelve adult patients who had sustained a condylar fracture, either alone or in combination with other mandibular fractures, were clinically and radiologically assessed for the efficacy and stability of bioresorbable plate and screw fixation. Intraoperatively, a total of seven screw breakages were noted. Six cases showed instability of the fractured fragments after fixation with bioresorbable plates and screws; the other six cases showed adequate stability. A single bioresorbable plate does not provide satisfactory stability for condylar fractures. Also, the screw breakages add additional surgical time and cost to the patient.
The use of metallic bone plates and screws for internal fracture fixation is considered to be a reliable method for achieving undisturbed fracture healing. Nevertheless, there are several disadvantages associated with the use of metallic implants, including the possibility of bone atrophy as a result of stress shielding by the rigid bone plates and screws. This is one of the main reasons for removal of the metallic plates and screws in a second surgery. Other disadvantages of metallic implants include interference with radiation therapy and the production of artefacts in computerized tomography (CT) and magnetic resonance imaging (MRI).
Corrosion, allergy, palpability, loosening, and hypersensitivity to cold are additional difficulties with the use of metallic implants. Furthermore, problems with regard to metallic fixation in the growing craniofacial skeleton, such as intracranial migration and growth retardation, are well documented.
Bioresorbable osteosynthesis devices offer numerous advantages over metallic implants. The elasticity of bioresorbable materials is close to that of bone and will enhance stress protection when bone support is no longer required. The bioresorbable materials gradually disappear and transfer the stress to the healing bone, thus obviating the need for implant removal.
There are several bioresorbable materials available today with slightly different properties in terms of elasticity, malleability, handling, and biodegradation. Today bioresorbable plates and screws are being used increasingly in maxillofacial surgery in areas as diverse as trauma, orthognathic surgery, craniofacial surgery, access osteotomies, and cancer surgery.
We evaluated the efficacy of bioresorbable plate fixation in condylar fractures in 12 patients based on their obvious advantages and limitations over the metallic implants.
Materials and methods
A detailed clinical and radiological analysis was made of 12 patients (eight males and four females) who required internal fixation of the mandibular condylar region, which was treated using bioresorbable plates and screws. Patients over 18 years of age with a simple or closed condylar/subcondylar fracture, either alone or in combination with other mandibular fractures, were included in this study. Patients with comminuted fractures and those not willing to participate in the study were excluded. Institutional ethical approval was obtained, as well as written informed consent from all of the patients.
A thorough clinical and radiographic analysis (postero-anterior (PA) radiograph of the skull and orthopantomogram (OPG)) was carried out to evaluate the need for internal fixation of the fractured mandibular condyle ( Fig. 1 ). All fracture sites were exposed after maxillomandibular fixation under general anaesthesia using a retromandibular approach. Fixation of the fractured condylar segment was achieved using a single 2-mm four-hole poly- l -lactide bioresorbable plate and four screws of 2 mm × 8 mm (Inion Ltd., Tampere, Finland). After fixation of the segments with the bioresorbable plate, the maxillomandibular fixation was released.
Radiographic evaluation, consisting of a PA radiograph of the skull and an OPG, was carried out in the immediate postoperative period (day 2 postoperative) and at postoperative week 6 ( Fig. 2 ). Clinical analysis (stability of the fractured segments, occlusion, need for intermaxillary fixation, mouth opening and deviation) was carried out at postoperative weeks 1, 2, 4, and 6. All the relevant data were collected in the prescribed format and analyzed.
Clinically evident acceptable occlusion and stability of the bone fragments without displacement in the postoperative radiographs were considered evidence of a satisfactory result. Conversely, cases showing discrepancy in occlusion clinically and demonstrating an obvious gap between bony fragments on postoperative radiographs were considered to have an unsatisfactory result. All cases not fulfilling the above criteria for a satisfactory outcome and cases for whom the biodegradable plate had to be replaced with a metallic plate to achieve stability were considered failures.