https://orcid.org/0000-0002-1671-3764
Abstract
Temporomandibular joint (TMJ) ankylosis in growing patients may result in severe mandibular hypomobility, progressive dentofacial deformity and upper airway compromise. The selection of reconstructive treatment remains challenging because autologous reconstruction offers growth potential, whereas alloplastic replacement enables immediate mobilization and precise correction of complex deformities. We report the staged management of a 15-year-old female patient with bilateral destructive TMJ ankylosis, marked mandibular retrognathia and tracheostomy-dependent airway obstruction. Treatment consisted of Computer Aided Design/Computer Aided Manufacturing (CAD/CAM)-guided mandibular distraction followed by bilateral total alloplastic TMJ replacement (TMJ-TJR). Persistent aseptic soft-tissue swelling and confirmed chromium and nickel hypersensitivity required revision to all-titanium components 12 months later. After revision, the soft-tissue reaction resolved completely. At 12 months after completion of surgical treatment, mouth opening exceeded 3 cm, the patient was pain-free and facial aesthetics and subjective well-being had improved. This case illustrates the role of staged patient-specific alloplastic reconstruction in selected adolescent patients with advanced TMJ ankylosis.
Introduction
Ankylosis of the temporomandibular joint (TMJ) is characterized by fibrous or bony fusion between the mandibular condyle and the glenoid fossa. It may be intra- or extra-articular; common causes include trauma, infection, periarticular tumour growth, coronoid hyperplasia, ossifying myositis, scarring, irradiation and persistent trismus [1, 2]. Progressive mandibular hypomobility is the leading clinical feature. In children and adolescents, TMJ ankylosis may additionally cause impaired mandibular growth, retrognathia or micrognathia, malocclusion, reduced nutrition, restricted oral hygiene and obstructive sleep apnoea [3–5]. Treatment therefore aims to remove the ankylosis, restore mandibular mobility and function, improve occlusion and aesthetics, and relieve upper-airway obstruction [3, 6]. Alloplastic TMJ replacement is established for severely damaged adult joints but remains controversial in growing patients because prostheses lack growth potential and revision may be required [6]. We report a staged Computer Aided Design/Computer Aided Manufacturing (CAD/CAM)-based reconstruction in an adolescent with bilateral TMJ ankylosis, severe retrognathia and airway compromise. The treatment combined mandibular distraction, patient-specific bilateral TMJ replacement and, after the development of implant material hypersensitivity, revision to all-titanium components.
Case report
A 15-year-old female patient presented with her parents in March 2021 for assessment of progressive restriction of mouth opening and increasing mandibular retrognathia. Her parents denied early childhood craniofacial trauma or relevant medical history. No previous orthodontic or maxillofacial surgical treatment had been performed.
Clinical examination showed a maximum incisal opening of 0.3 cm, skeletal class II relationship, pronounced mandibular micrognathia and retrognathia, Angle class II/1 occlusion, an overbite of 2.8 mm and an overjet of 20 mm. Mild chin deviation to the right was present. The dental status required rehabilitation, with several teeth considered non-restorable, because oral hygiene was severely limited. Owing to marked upper-airway narrowing, the patient had already undergone tracheostomy. The tracheostomy and restricted mandibular function substantially impaired speech, everyday activity and age-appropriate social participation (Fig. 1a–d).
Clinical situation at first presentation showing facial asymmetry and incompetent lip closure in frontal view (a), intraoral frontal view with anterior open bite and malpositioned teeth (b), pronounced mandibular retrusion with reduced lower facial height in right lateral view (c) and angle class II occlusion with vertical insufficiency in lateral view (d).
Cone-beam computed tomography confirmed bilateral destructive TMJ arthrosis with ankylosis: Sawhney type III-IV on the right and type III on the left, with extensive periarticular ossification, loss of condylar morphology and absent joint-space demarcation. Both joints were consistent with Wilkes stage V disease [7, 8] (Fig. 2a–c). Because of severe mandibular hypomobility, the required sagittal advancement and shortened perimandibular soft tissues with a high risk of skeletal relapse, a two-stage concept was chosen: primary mandibular distraction to lengthen the soft-tissue envelope, followed by bilateral alloplastic CAD/CAM TMJ reconstruction and maxillary advancement. Orthodontic pretreatment was deferred because the restricted mouth opening did not permit adequate access and the sagittal skeletal discrepancy first required surgical correction.
Skeletal situation at first presentation with bilateral destructive temporomandibular joint arthrosis and ankylosis.
In March 2022, ventrocaudal mandibular distraction was performed using CAD/CAM-guided placement of a Zurich Wood Distractor (KLS Martin, Tuttlingen, Germany). After a 3-day latency period, distraction was performed over 2 weeks: 7.5 mm vertically and 13.5 mm horizontally on the right, and 7.5 mm vertically and 13.0 mm horizontally on the left (Fig. 3a–d). After 10 months of consolidation, bilateral total CAD/CAM TMJ replacement (TMJ-TJR) was performed using patient-specific implants (Zimmer Biomet, Warsaw, IN, USA). This sequence allowed gradual advancement before definitive reconstruction rather than forcing the full correction during a single operation. The immediate postoperative course was uneventful.
Virtual surgical planning with distractor position before (a) and after completion of distraction (c), intraoperative situation after distractor placement (b) and postoperative CBCT in lateral 3D reconstruction (d). Clinical appearance before distraction (e) and after completed distraction with improved soft-tissue profile allowing decannulation (f).
During follow-up, however, persistent aseptic swelling developed in both masseteric regions. Allergological testing demonstrated chromium and nickel hypersensitivity. Revision to an all-titanium prosthetic configuration was therefore performed in March 2024 after completion of renewed virtual planning and implant production. Both condylar components and the left fossa component were replaced; the latter was indicated because skull-base erosion was present beneath the in situ ultra-high molecular weight polyethylene fossa component (Figs 4 and 5a–f). After revision, the swelling resolved completely. Immediate postoperative mobilization used the TheraBite® (Atos Medical, Troisdorf, Germany) system according to the manufacturer’s 7-7-7 protocol, followed by physiotherapy and speech therapy from week 4. Twelve months after completion of surgery, mouth opening exceeded 3 cm, the patient was pain-free and facial aesthetics and well-being had improved. The patient also reported a clear subjective improvement in daily function after resolution of the airway and speech limitations. Orthodontic treatment began 6 months after the third operation. The current situation is presented in Fig. 6.
Coronal CT section showing skull-base erosion on the left side beneath the in situ UHMWPE fossa component.
Virtual planning of bilateral total alloplastic CAD/CAM TMJ replacement (a–c) and postoperative result in 3D CT reconstruction (d–f).
Clinical findings 12 months after the second bilateral total alloplastic CAD/CAM TMJ replacement with conversion to all-titanium components, showing a symmetrical facial profile and competent lip closure in frontal view (a), balanced soft-tissue profile in right lateral view (b), and intraoral frontal (c) and lateral views (d) with regular occlusion during ongoing orthodontic treatment.
Discussion
Guidelines recommend early surgery for progressive ankylosis because complications and re-ankylosis increase in advanced stages [3, 6]. In severe disease, complete removal of the ankylotic mass and early postoperative mobilization are essential, while extensive loss of condylar height and secondary dentofacial deformity often require reconstruction [2, 3, 9]. CAD/CAM planning and patient-specific implants are particularly useful in such complex anatomy because the required resection, implant position and occlusal correction can be planned together.
The indication for alloplastic TMJ-TJR in adolescents remains difficult. Autologous costochondral grafts have traditionally been preferred because of growth potential, but donor-site morbidity, unpredictable growth, resorption and re-ankylosis are important limitations. Modern patient-specific alloplastic systems allow precise correction, immediate mobilization and avoidance of graft morbidity. In selected adolescents with severe ankylosis, failed or clinically irrelevant residual condylar growth, major airway compromise or pronounced dentofacial deformity, these advantages may justify accepting the possibility of later revision [9–12]. The staged distraction used in this case was intended to reduce soft-tissue tension before definitive joint reconstruction. This may be particularly relevant in patients with long-standing ankylosis, in whom peri-mandibular soft-tissue shortening can otherwise compromise the stability of large sagittal corrections.
This case also highlights postoperative metal hypersensitivity as a differential diagnosis in persistent aseptic swelling after TMJ replacement. Low-grade infection and mechanical irritation must be excluded. In patients with confirmed chromium or nickel hypersensitivity, conversion to titanium-based components has been reported to improve symptoms [13, 14]. In the present patient, conversion to all-titanium components led to complete regression of the soft-tissue reaction. The staged approach enabled functional recovery, decannulation-relevant profile improvement and a satisfactory aesthetic outcome in a complex adolescent case.
Conflicts of interest
None declared.
Funding
None declared.
