Key points
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Complications of temporomandibular joint (TMJ) total joint replacement include facial nerve injury, infection, heterotopic ossification, hardware failure, and synovial entrapment, requiring prompt management.
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Revision TMJ surgery demands meticulous preoperative evaluation, including detailed surgical history, high-resolution computed tomography imaging, and consideration of staged reconstruction in complex cases.
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Structured postoperative physiotherapy significantly improves range of motion, pain, and masticatory function and is essential to prevent reankylosis following open TMJ surgery.
Abbreviations
| CT | computed tomography |
| HO | heterotopic ossification |
| IMA | internal maxillary artery |
| TJR | total joint replacement |
| TMJ | temporomandibular joint |
Introduction
Complications following temporomandibular joint (TMJ) surgery are diverse and present unique challenges for the TMJ surgeon. Risk of complications increases in proportion to surgical complexity, as well as with prior interventions, anatomic alterations, and patient comorbidities. Effective management of TMJ surgical complications requires not only prompt recognition and comprehensive understanding of their etiology and strategies for prevention. This article provides an overview of various complications related to open joint procedures with a particular focus on total alloplastic TMJ replacement surgery.
Neurologic complications: facial nerve injury
Facial nerve injury, although rarely permanent, remains a commonly reported complication of TMJ total joint replacement (TJR) ( Figs. 1–3 ). A systematic review by Peres Lima and colleagues reported facial nerve paresis or paralysis as the most prevalent complication of total joint replacement, occurring in 7.8% of cases. The vast majority of deficits are transient, with normal function returning within 9 to 14 weeks, though permanent injury has been documented in rare cases. Identification of key tissue planes remains paramount during dissection to the TMJ, including ensuring that anterior dissection along the lateral aspect of the zygomatic arch is performed in a subperiosteal plane, deep to the temporal branch of the facial nerve. The surgical team should also avoid excessive inferior retraction within a preauricular incision to minimize traction injury to the trunk of the facial nerve.
( A–C ) A patient with history of multiple TMJ surgeries resulting in damage to the facial nerve.
Computed tomography (CT) imaging of a left TMJ prosthesis with screw fracture and prosthesis displacement. Note the gap between the lateral mandibular cortex and prosthesis ( arrow ).
CT imaging 3D reconstruction of patient with screw failure and displacement of mandibular prosthesis.
Periprosthetic joint infection
A retrospective survey of 2,476 TJR cases involving 3,368 joints, Mercuri reported a surgical site infection rate of 1.51%, similar to the incidence of 2.5% of patients or 1.6% of all prostheses reported by Wolford. Acute infections, defined by Wolford as those diagnosed and treated within 2 to 5 days of symptom onset, may be effectively managed with irrigation, debridement, and targeted antibiotic therapy, with reported prosthesis salvage rates approaching 80%. In contrast, chronic infections require a staged approach involving prosthesis removal, placement of an antibiotic spacer, and delayed reimplantation. Prevention strategies include meticulous preoperative risk assessment, appropriately timed antibiotic prophylaxis, strict adherence to sterile technique, careful intraoperative hemostasis and tissue handling, and vigilant postoperative surveillance.
Hardware failure
Hardware failure in TMJ TJR may present as screw loosening, fracture of fixation screws or prosthetic components (fossa or mandibular), and prosthesis displacement (see Figs. 2 and 3 ). Ettinger and colleagues demonstrated that increasing the number of fixation screws in the condylar component reduces per-screw stress and may decrease the risk of hardware failure. Although relatively uncommon with contemporary prosthetic systems, hardware failure was more prevalent in historical designs, including the Christensen TMJ prosthesis, in which fossa component fractures were frequently observed during revision. Trauma represents an additional mechanism of failure; fractures of mandibular ramus screws with associated prosthesis displacement have been reported following falls and other blunt force injuries, often necessitating device replacement. Hardware failure is typically treated with removal and replacement of the prosthesis. Strategic placement of new screws to avoid previously occupied or compromised bone can optimize fixation and reduce the risk of repeat failure.
Implant exposure and dehiscence
Implant exposure may occur through a preauricular incision, submandibular incision, or intraorally along the mandibular ramus ( Fig. 4 ). Contributing factors include thin soft tissue coverage, previous irradiation (as in cases of osteoradionecrosis requiring reconstruction), poor wound healing, and chronic low-grade infection. Management typically requires soft tissue debridement, local or regional flap coverage, and in refractory cases, prosthesis removal with staged reconstruction. In complex cases involving prior radiation, microvascular free tissue transfer such as fibular free flap may be required for definitive reconstruction.
Left TMJ TJR implant exposure in a patient with a history of head and neck radiation.
Heterotopic ossification
Heterotopic ossification (HO) is one of the most frequently cited reasons for TJR revision surgery ( Fig. 5 ), reported as high as 20% in the absence of prophylactic measures. HO can result in progressive limitation of mouth opening, reankylosis, and the need for revision surgery. The etiology is multifactorial and may involve periosteal disruption, residual bone fragments, and the patient’s inherent osteogenic potential.
Periprosthetic heterotopic ossification ( arrow ) medial to the condylar component.
Autologous fat grafting has emerged as the primary prophylactic measure against HO formation ( Figs. 6 and 7 ). Wolford and Karras published the first study of this technique for TMJ TJR in 1997 and subsequent investigations have demonstrated a substantial reduction in HO rates to less than 5% when autologous fat is packed around the articulating components of the prosthesis. In patients who develop recurrent HO despite fat grafting, management typically involves atraumatic prosthesis removal, thorough resection of heterotopic bone, replacement of the prosthesis, and reapplication of autologous fat around the articulation.
Autologous fat graft positioned over TJR surgical site. The prosthesis is visible within the incision.
Fat graft has been packed into the surgical site around the prosthesis.
Intraoperative bleeding
Preoperative internal maxillary artery (IMA) embolization is a well-established adjunct for decreasing blood loss during open TMJ procedures, especially in cases of ankylosis release and TJR. A recent 10-year institutional experience of 73 patients (108 sides) undergoing preoperative IMA embolization before TMJ replacement demonstrated median operative blood loss of only 100 mL per side (interquartile range [IQR] 50–181 mL), with half the number of patients experiencing excessive blood loss compared to historical controls (12.5% vs 25%). The procedure is typically performed using coils ( Fig. 8 ) with a median of 3 coils per side, sometimes combined with n-butyl cyanoacrylate (glue); the middle meningeal artery may also be occluded in approximately 26% of cases.
Panoramic radiograph demonstrating platinum embolization coils ( arrows ) placed during embolization of bilateral internal maxillary arteries.
Embolization is generally performed 24 to 48 hours before surgery and surgery should proceed within this window to prevent collateral revascularization. Preoperative CT angiography is essential to assess the relationship between the IMA/external carotid artery and the ankylotic mass or surgical field, with embolization indicated when intimate anatomic association is present.
Synovial entrapment
Identifying the cause of periprosthetic pain and limited mandibular opening after TMJ TJR can be challenging, with a broad differential that includes myofascial pain, centrally mediated pain, and other postoperative complications. When clinical and radiographic findings do not reveal a clear etiology, synovial entrapment should be considered. Also referred to as synovial impingement, synovial entrapment occurs when synovial tissue proliferates and becomes interposed within the articulating surfaces of prosthesis. This phenomenon has been described in hip and knee arthroplasty as well as in both stock and patient-specific TMJ prostheses. Synovial entrapment is rarely reported, likely because definitive diagnosis typically requires surgical exploration of the prosthetic joint since soft tissue ingrowth may not be visualized on radiographic workup. Management generally involves open or arthroscopic debridement of soft tissue interposed between the prosthetic components. Histopathologic evaluation of the periprosthetic pseudocapsular tissue can confirm the presence or absence of entrapped synovium.
Figs. 9 and 10 show the left total joint replacement of a 65 year old female 5 years after placement of the prosthesis. In the years before her revision surgery, the patient began to experience progressive joint pain with function and decreased oral opening. Without other significant findings on clinical examination and CT imaging negative for signs of prosthetic failure, the patient was taken to the operating room for open exploration of the prosthesis. Upon access to the joint, a soft tissue encapsulation of the condylar component was identified, occupying the space between the articulating surfaces (see Fig. 9 arrow). This tissue was removed with hand instrumentation (see Fig. 10 ) and sent for histopathologic analysis. Biopsy results confirmed reactive synovium with degenerative changes.
