UK temporomandibular joint replacement database: report on baseline data

Effect of duration of preoperative pain on outcomes of total temporomandibular joint replacement

The purpose of the study was to determine whether the duration of preoperative pain affects outcomes of temporomandibular joint replacement (TMJR). Twenty-seven patients who underwent primary TMJR between 1 July 2020 and 31 October 2022 were retrospectively assessed for duration of preoperative pain, level of preoperative and postoperative pain on a visual analogue scale (VAS; 0, none; 10, severe), preoperative and postoperative range of motion (ROM), and net change in quality of life (much better, better, same, worse, much worse), reporting the longest available follow up for each patient. Surgical success was defined as postoperative pain of ≤4 and postoperative ROM of ≥30 mm, or net change (Δ) in ROM of ≥10 mm. Regression analyses evaluated associations between independent variables and postoperative pain and ROM. At a mean follow-up of 17.8 (SD: 6.8, range 3-32) months , pain (5.1, SD: 2.2, p < 0.001) and ROM (9.3 mm, SD: 8.0, p<0.001) significantly improved. Quality of life was much better in 16 patients, better in eight, the same in one, and worse in two. Longer duration of preoperative pain tended to be negatively associated with postoperative ROM (β = -0.27; 95% CI -0.6 to 0.0; p = 0.078) but was not associated with severity of postoperative pain. Surgical success was achieved in 23/27 patients. The successful group tended to have lower pain on VAS preoperatively (5.9, SD: 1.9) vs 7.5, SD: 1.3) and postoperatively (0.4, SD: 0.8 vs 4.8, SD: 2.6), and greater improvement in quality of life (much better: 14/23 vs 2/4). In conclusion, longer duration of preoperative pain tended to be associated with worse postoperative ROM following TMJR. Higher preoperative pain may be a predictor for unsuccessful surgery.

Temporomandibular joint prosthesis as treatment option for mandibular condyle fractures: a systematic review and meta-analysis

The aim of this study was to perform a systematic review of the literature on the temporomandibular joint (TMJ) prosthesis as a treatment option after mandibular condyle fracture. Three databases were searched (PubMed, Embase, Cochrane Library) and 2670 unique papers were identified. A total of 337 studies were included (121 case reports, 89 case series, and 127 cohort/clinical studies). In total 14,396 patients and 21,560 prostheses were described. Of the 127 cohort or clinical studies, 100 (79%) reported inclusion criteria, 54 (43%) reported exclusion criteria, and 96 (76%) reported the inclusion period. The base population from which patients were recruited was reported in 57 studies (45%). The reason for TMJ prosthesis implantation was reported for 4177 patients (29.0%). A history of condylar fracture was present in 83 patients (2.0%); a history of mandibular trauma was present in 580 patients (13.9%). The meta-analysis showed a pooled prevalence of condylar fracture of 1.6% (95% confidence interval 0.9-2.4%) and a pooled prevalence of trauma or condylar fracture of 11.3% (95% confidence interval 7.1-16.0%). Heterogeneity was highly significant (P < 0.001). The TMJ prosthesis appears to be reserved for patients with persistent pain, bony or fibrous ankylosis, or osteomyelitis after primary closed or open treatment of fractures of the mandibular condyle.

An updated view on Temporomandibular Joint degeneration: insights from the cell subsets of mandibular condylar cartilage

The high prevalence of temporomandibular joint osteoarthritis (TMJOA), which causes joint dysfunction, indicates the need for more effective methods for treatment and repair. Mandibular condylar cartilage (MCC), a typical fibrocartilage that experiences degenerative changes during the development of TMJOA, has become a research focus and therapeutic target in recent years. MCC is composed of four zones of cells at various stages of differentiation. The cell subsets in MCC exhibit different physiological and pathological characteristics during development and in TMJOA. Most studies of TMJOA are mainly concerned with gene regulation of pathological changes. The corresponding treatment targets with specific cell subsets in MCC may provide more accurate and reliable results for cartilage repair and TMJOA treatment. In this review, we summarized the current research progress on the cell subsets of MCC from the perspective of MCC development and degeneration. We hope to provide a reference for further exploration of the pathological process of TMJOA and improvement of TMJOA treatment.

Total Alloplastic Temporomandibular Joint Replacement

Purpose

End-stage temporomandibular joint (TMJ) disease are not uncommon and affects quality of life. Multiple surgical procedures have been mentioned in literature for management of TMJ disease which ranges from conservative management to aggressive resection of involved joint and replacement with alloplastic total joint prosthesis. The purpose of the present paper was to provide an overview of the role of alloplastic total joint prosthesis in TMJ replacement.

Methods and results

Alloplastic total joint prosthesis is nowadays considered as a standard of care in the adult patients who require TMJ replacement. The requirement of alloplastic total prosthesis has increased in present era with the improvement in design and material of implants, surgical skills and reported victorious outcome along with improved quality of life after its use. It provides restoration of form and functions, improvement in quality of life, reduction in pain and maintenance of ramal height. Additionally, in TMJ ankylosis it reduces chances of re-ankylosis and allows facial asymmetry correction. Currently, enough evidence is however not available for replacement in skeletally immature patient.

Conclusion

The authors conclude that the total joint replacement is a standard procedure for end-stage TMJ disease. Every maxillofacial surgeon should be well-acquainted with TMJ replacement.

Prospective study of the long-term outcomes and complications after total temporomandibular joint replacement: analysis at 10 years

This prospective analysis was performed to assess the long-term benefits of the TMJ Concepts joint replacement system in the UK. All patients who had replacement temporomandibular joints (TMJ) with at least 10 years of follow-up were included. The most common primary diagnoses were trauma, multiple previous operations, psoriatic arthritis, rheumatoid arthritis, degenerative disease, and ankylosis. A total of 43 patients (62 joints) were followed up for 10 years (mean age 45, range 22-70 years); 39 were female and four were male. The mean number of previous TMJ procedures was 2.5 (range 0-10). Over the 10 years of follow-up, there were significant improvements in pain score (10-point scale; decreased from 7.4 to 1.7), maximum mouth opening (increased from 21.0 mm to 34.7 mm), and dietary score (10-point scale; increased from 4.1 to 9.5). Joints in two patients failed, one secondary to a local dental infection and one due to reankylosis. None failed due to wear of the prosthesis, whether the prosthesis was standard cobalt-chrome or all-titanium. Total TMJ replacement gives good long-term improvements, both lessening pain and improving function, and is an effective form of management for irreparably damaged joints.

Alloplastic total joint replacement in management of temporomandibular joint ankylosis

Both autogenous and alloplastic material have been used in management of temporomandibular joint (TMJ) ankylosis. Second surgical site, donor site morbidity, possibility of over/undergrowth, graft fracture or resorption and increased surgical time are the disadvantages of autogenous graft. Alloplastic total joint replacement (TJR) has become a promising technique in management of adult temporomandibular joint ankylosis (TMJA). This paper intends to present the role of alloplastic TJR in management of TMJA. There is significant current evidence of the role of alloplastic TJR in the management of TMJA. Results in TMJA are excellent with sustained improvement in pain free mouth opening, correction of facial asymmetry, reduction in recurrence and improved quality of life. TMJ TJR is becoming the gold standard of care in the management of TMJA, although costs can sometime preclude access to this mode of therapy.

Does Maximum Voluntary Clenching Force Pose a Risk to Overloading Alloplastic Temporomandibular Joint Replacement?-A Prospective Cohort Study

PURPOSE

The amount of maximum voluntary clenching (MVC) force may influence functional loading at the polyethylene/metal bearing surfaces in alloplastic total temporomandibular joint replacement (TMJR). The aim of this study was to measure ipsilateral MVC and estimate the risk for revision due to overloading of the TMJR.

METHODS

A prospective cohort study design was used to study patients who underwent alloplastic TMJR. The primary predictor was time after TMJR, the secondary predictors were age at TMJR placement, coronoidectomy, prior ipsilateral TMJ surgeries, TMJR design (custom, stock), and bite location. The primary outcome variable was MVC, the secondary outcome was need for TMJR revision. Data were collected preoperatively (T0), and 1 year (T1), 2 to 3 years (T2) and ≥4 years postoperatively (T3). Analysis of variance (ANOVA) with post hoc Tukey-HSD and regression analysis was used for statistical analysis. P < .05 was considered significant.

RESULTS

Thirty-seven patients (58 TMJR) with unilateral (n = 16) and bilateral (n = 21) TMJR were enrolled; 8 males (12 TMJR) and 29 females (46 TMJR). Average age was 46.4 ± 14.9 years. MVC increased significantly over the observation period (P = .000). At all observation time points, age at TMJR placement and bite location significantly influenced MVC (P = .000). Coronoidectomy and prior ipsilateral TMJ surgeries did not demonstrate a significant influence on MVC. TMJR design influenced MVC significantly at T3 (P = .006). Regression analysis identified age as a significant factor for higher MVC. No TMJR required revision or replacement.

CONCLUSIONS

Based on this study, ipsilateral MVC increases significantly after TMJR. However, since MVC is significantly lower than in healthy test-patients, a considerably lower functional loading at the polyethylene/metal bearing surfaces can be assumed. Lower loading at the TMJR bearing surfaces and at the cortical screw fixation sites suggest a potential longer lifespan compared to other artificial joints like hip and knee prostheses.

The healthcare burden and associated adverse events from total alloplastic temporomandibular joint replacement: a national United States perspective

The purpose of this study was to provide a United States perspective on alloplastic total joint replacement. We sought to estimate the inpatient burden and report the most common adverse events using two administrative datasets. The National Inpatient Sample was queried from October 2015 to December 2016 for total joint replacement admissions using International Classification of Diseases 10^th revision codes, and the Manufacturer and User Facility Device Experience registry was queried from January 2009 to September 2019 using manufacturer brands. The combined final sample included 114 inpatient admissions and 392 adverse events. Mean age was 43.1 years, and most patients were white (82.7%) and female (86.0%). The mean hospital charge was $108,709.43 and the mean length of stay was 2.6 days. The most common adverse events were infection (26.3%), heterotopic bone (20.9%), and poor intraoperative fit (14.0%). Fifty-four percent of cases had bilateral total joint replacements, 24.6% had simultaneous subcutaneous abdominal fat grafting, and 11.4% had simultaneous maxillary repositioning. Fat grafting and maxillary repositioning were not associated with any significant difference in the length of stay or cost. Compared to unilateral cases, bilateral total joint replacements carried significantly greater charges (P<0.01), but no increased length of stay (P=0.70), suggesting that bilateral and unilateral cases may experience a similar postoperative course.

Outcome of Stock Total Joint Replacement With Fat Grafting in Adult Temporomandibular Joint Ankylosis Patients

PURPOSE

Adult temporomandibular joint ankylosis (TMJA) lacks a uniform management protocol. The purpose of the study was to evaluate the outcome of stock total joint replacement (TJR) along with fat grafting around the joint in adult TMJA patients. Specific aim was to find out whether TJR can be a definitive management for adult TMJA.

METHODS

The investigators implemented a prospective study on adult TMJA patients treated with ostearthrectomy of ankylosis and stock temporomandibular joint (TMJ) TJR with fat grafting. Concomitant orthognathic correction of facial asymmetry was performed in some unilateral cases. Follow-up was carried out at regular intervals for assessing primary outcome variable of maximal incisal opening (MIO) and reankylosis. Secondary outcome variable included demographic data, etiology, duration of ankylosis (DOA), correlation between DOA and preoperative and postoperative MIO, occlusion and complications of hemorrhage, facial nerve paresis, periprosthetic joint infection, dislocation, and implant failure.

RESULTS

The study sample was composed of 41 patients (54 joints) (bilateral, n = 13; unilateral, n = 28 [right side, n = 12; left side, n = 16]). The number of recurrent cases was 15. Trauma as etiology of ankylosis was seen in n = 30 (73.2%), infection in n = 7 (17.1%), unknown in n = 3 (7.3%), and ankylosing spondylitis in n = 1 (2.4%) cases. Mean DOA was 11.95 years. Paired t test revealed a statistically significant difference between preoperative and follow-up MIO (P < .001). None of the cases showed reankylosis in the follow-up period. Pearson correlation revealed statistically negative correlation between DOA and postoperative MIO.

CONCLUSIONS

The result of this study suggests that stock TMJ TJR along with fat grafting around the joints provides adequate mouth opening without any sign and symptoms of reankylosis. Stock TMJ TJR with fat grafting can be considered as a definitive treatment modality in adult TMJA with minimum comorbidity.

Clinical guidelines for total temporomandibular joint replacement

Total joint replacement (TJR) of the temporomandibular joint (TMJ) is a promising surgical procedure and device for treating end-stage diseases of the TMJ. For the functional and aesthetic reconstruction of the oral and maxillofacial head and neck region, TMJ TJR significantly helps maintain the patient's quality of life in terms of a better diet, mastication, speech and social interaction. TMJ TJR was approved by regulatory authorities in 2019 in Japan, thus enabling the clinical application of the TJR system. However, the surgery demands particularly difficult and high-risk procedures, necessitating the prudent selection of indicated patients. The joint committee of the Japanese Society of Oral and Maxillofacial Surgeons and Japanese Society for Temporomandibular Joint is working together to develop an appropriate clinical guideline for TMJ TJR.

Vascularized scapula and latissimus dorsi flap for CAD/CAM assisted reconstruction of mandibular defects including the mandibular condyle: technical report and clinical results

Background

Reconstruction of mandibular continuity and function after tumor resection is challenging, particularly in cases including the mandibular condyle. Various approaches for reconstruction after disarticulation resection have been reported. However, the scapula flap has received little attention as a treatment option in these cases.

Patients and methods

Three cases of computer aided design and computer aided manufacturing (CAD/CAM) assisted reconstruction after disarticulation resection using a vascularized scapula and latissimus dorsi flap are reported. All cases required reconstruction of the mandibular ramus and condyle in combination with the reconstruction of large and complex soft tissue defects.

Results

The surgical procedure was deemed successful in all cases. The scapula flap could be placed as preoperatively planned and patients regained their preoperative occlusion pattern and satisfying mouth opening-ranges. The large soft tissue defects could reliably be reconstructed using a latissimus dorsi flap.

Conclusions

The scapula and latissimus dorsi flap can be considered a suitable option for the reconstruction of mandibular disarticulation resection defects in combination with large soft tissue defects.

Evaluation of the 3 mm Thickness Splint Therapy on Temporomandibular Joint Disorders (TMDs)

Objective. This study aimed at finding out whether the 3 mm thickness of stabilization splints has positive or negative effects on all temporomandibular disorder (TMD) symptoms. Materials and Methods. The statistical calculation included 25 (22 females; 3 males) TMD patients who received 3 mm thickness stabilization splint therapy. They were evaluated according to follow-up treatment period, TMD pain, muscle pain, mouth opening, diet score, and splint usage time per day. Results. There was important treatment success that 22 (88%) of patients were totally healed. There was not any remarkable effect or advancement of splints on total healings of TMDs in first 3 months' period (11/25 patients, 44%). The mouth opening mean reached 38, 67 mm at 6 months and 41 mm at 12 months with remarkable success. Except one (4%) patient, other 24 (96%) patients had a normal diet score of 3 at the end of splint therapy. There was no correlation between splint usage duration a day and total healing of TMDs. Conclusion. We conclude that 3 mm splint therapy should maintain at least 6 months to achieve remarkable results. Splint should be used at least 12 h a day consistent with our results. Finally, diet score should be incorporated with TMD pain and amount of mouth opening; hence, we advise to use in one term as “total healing.”

Ex-vivo and in vitro validation of an innovative mandibular condyle implant concept

PURPOSE

The purpose of this study is to pre-validate an inovative implant concept, and to compare the behavior of the mandibular condyle against a commercial Biomet implant in an ex vivo model and present results of the first cadaveric studies.

MATERIALS AND METHODS

Three experimental cadaveric condyles were tested under three conditions: one intact, another with the Biomet model, and one with the innovative concept. The condyle was tested with a reaction of 300 N in all situations and the principal strains were measured. Before the geometry of the cadaveric condyle was reconstructed from a microCT scan, and a finite element model was created. Finally, a procedure was carried out with the new implant by two expert surgeons on a two cadaveric head model.

RESULTS

In vitro the mandible condyle presents a linear behavior until maximum load. The strain measured with Biomet implant indicates a strain shielding effect in the proximal region, inducing bone loss in the long term. The lingual side of the Biomet implanted condyle presents an increase of +44% in strain.

CONCLUSION

The new concept was evaluated and showed a similar behavior to the intact model, and better behavior than the Biomet. The innovative concept proves that it is possible to avoid screws for a TMJ fixation and improve the TMJ alloplastic behavior.

A review of temporomandibular joint-related papers published between 2014-2015

We conducted a retrospective study and reviewed the temporomandibular joint (TMJ)-related papers published in a leading international journal, Journal of Oral and Maxillofacial Surgery, between January 2014 and December 2015. The study was conducted to ascertain and compare the trends of articles being published in the years 2014 and 2015. A total of 28 articles were reviewed, of which most of the full-length articles were on clinical management and outcomes and the role of radiology. The bulk of the studies were prospective, and less interest was shown in experimental research. A thorough review and analysis thus gives the impression that there is a great need for well-designed clinical studies on TMJ.

Mesenchymal Stem Cells for Cartilage Regeneration of TMJ Osteoarthritis

Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative disease, characterized by progressive cartilage degradation, subchondral bone remodeling, synovitis, and chronic pain. Due to the limited self-healing capacity in condylar cartilage, traditional clinical treatments have limited symptom-modifying and structure-modifying effects to restore impaired cartilage as well as other TMJ tissues. In recent years, stem cell-based therapy has raised much attention as an alternative approach towards tissue repair and regeneration. Mesenchymal stem cells (MSCs), derived from the bone marrow, synovium, and even umbilical cord, play a role as seed cells for the cartilage regeneration of TMJ OA. MSCs possess multilineage differentiation potential, including chondrogenic differentiation as well as osteogenic differentiation. In addition, the trophic modulations of MSCs exert anti-inflammatory and immunomodulatory effects under aberrant conditions. Furthermore, MSCs combined with appropriate scaffolds can form cartilaginous or even osseous compartments to repair damaged tissue and impaired function of TMJ. In this review, we will briefly discuss the pathogenesis of cartilage degeneration in TMJ OA and emphasize the potential sources of MSCs and novel approaches for the cartilage regeneration of TMJ OA, particularly focusing on the MSC-based therapy and tissue engineering.

[Total temporomandibular joint prostheses]

The temporomandibular joint (TMJ) is probably the most complex human joint. As in all joints, its prosthetic replacement may be indicated in selected cases. Significant advances have been made in the design of TMJ prostheses during the last three decades and the indications have been clarified. The aim of our work was to make an update on the current total TMJ total joint replacement. Indications, contraindications, prosthetic components, advantages, disadvantages, reasons for failure or reoperation, virtual planning and surgical protocol have been exposed.

A new condyle implant design concept for an alloplastic temporomandibular joint in bone resorption cases

The purpose of this article is to present and evaluate an innovative intramedullary implant concept developed for total alloplastic reconstruction in bone resorption cases. The main goal of this innovative concept is to avoid the main problems experienced with temporomandibular (TMJ) devices on the market, associated with bone fixation and changes in kinematics. A three-dimensional finite element model was developed based on computed tomography (CT) scan images, before and after implantation of the innovative implant concept. To validate the numerical model, a clean cadaveric condyle was instrumented with four rosettes and loaded before and after implantation with the innovative concept TMJ implant. The experimental results validate the numerical models comparing the intact and implanted condyles, as they present good correlation. They show that the most critical region is around rosette #1, with an increase in strains in the proximal region of the condyle of 140%. The maximum principal strain and stress generated with the implant is less than 2200 με and 75 MPa in the posterior region of the cortical bone. Shortly after insertion of this press-fit implant, stress and strain results appear to be within the normal limits and show some similarities with the intact condyle. If these responses do not change over time, the screw fixation used at present could be avoided or replaced. This solution reduces bone resection and lessens surgical damage to the muscles.

How Many Temporomandibular Joint Total Joint Alloplastic Implants Will Be Placed in the United States in 2030?

PURPOSE

The purpose of this study is to provide a statistical projection of the number of alloplastic temporomandibular joint (TMJ) total joint replacements (TJRs) that will be performed in the United States through the year 2030.

MATERIALS AND METHODS

The program directors of all 101 Commission on Dental Accreditation-accredited oral and maxillofacial surgery training programs in the United States were surveyed online by use of a questionnaire developed using Redcap (Chicago, IL) over a 6-week period (February 2015-March 2015). The questionnaire included 19 questions related to each program's TMJ disorder and TMJ TJR curricula, as well as clinical experience. In addition, members of the American Society of Temporomandibular Joint Surgeons were surveyed online using Redcap and via direct survey forms. Moreover, requests for the total number of TMJ TJR devices produced and implanted during the same period were made to the 3 manufacturers of Food and Drug Administration-approved TMJ TJR devices in the United States.

RESULTS

The response rate among program directors was 52.5%, and the total number of TMJ TJR devices implanted in oral and maxillofacial surgery programs in 2005 was 412. This total increased by 38% to 572 in 2014. Statistically, this projects an increase of 58% over the next 16 years to 902 TMJ TJR operations by 2030 (95% prediction limits, 768 and 1,037). The total number of TMJ TJR devices distributed by one manufacturer increased from 430 in the year 2000 to 1,004 in 2014 (133%). By use of these data, statistically over the next 16 years, the number of TMJ TJR devices distributed by this company is projected to be 1,658 (95% prediction limits, 1,380 and 1,935).

CONCLUSIONS

The data presented in this study show an increasing demand for the use of TMJ TJR devices in the management of end-stage TMJ disorders to the year 2030.

Can a Novel Surgical Approach to the Temporomandibular Joint Improve Access and Reduce Complications?

PURPOSE

This clinical study investigated whether the vascular-guided multilayer preauricular approach (VMPA) to the temporomandibular joint (TMJ) could improve access and decrease complications.

PATIENTS AND METHODS

This retrospective evaluation consisted of a consecutive series of patients who underwent TMJ surgeries through the VMPA from January through December 2013. Patients with a history of TMJ surgery were excluded. Clinical data, including operating times, subjective complaints of incision scars, functional conditions of the auriculotemporal nerve and facial nerve, and other complications, were recorded and analyzed. All patients in this study were followed for at least 6 months.

RESULTS

All patients (606 joints) had successful TMJ surgeries through the VMPA. All incisions healed favorably with an uneventful recovery. No patient developed permanent weakness of the facial nerve or other severe complications.

CONCLUSION

The VMPA can provide direct access and favorable visibility to the TMJ region and yield good esthetic and functional results. The VMPA can be considered the approach of choice for common TMJ surgeries.

Christensen vs Biomet Microfixation alloplastic TMJ implant: Are there improvements? A numerical study

The objective of this study was to compare the load transfer mechanism and behavior of two total temporomandibular joint (TMJ) prostheses: Biomet and Christensen TMJ models were simulated. Computed tomography (CT) images from a specific patient were used to generate two models for use in simulation of implantation for the total temporomandibular prostheses. Three finite element models were created in all. One considered the intact temporomandibular joint and two received a temporomandibular implant. In the simulation we considered the five most important muscles acting on the mandible and incisor teeth support. The Christensen model reduced strain in the opposite condyle by around 50% while increasing strain in the implanted condyle. The changes in the posterior side of the implanted condyle present an increase of five times the minimum principal strain, suggesting some bone fatigue. With the Biomet implant, the reduction in strain in the implanted condyle on the posterior side was around 100%, suggesting the possibility of some bone loss proximally near the resection plane. Based on our results, we conclude that in both models the implants influence the behavior of the mandible by improving the symmetry of the mandible and strain distribution. The Biomet implant modifies the behavior of the mandible slightly and presents some improvements over the Christensen TMJ model in strain distribution and tensions in the opposite intact disc similar to the non-implanted situation.

Current understanding of pathogenesis and treatment of TMJ osteoarthritis

Osteoarthritis is a common disease that can cause severe pain and dysfunction in any joint, including the temporomandibular joint (TMJ). TMJ osteoarthritis (TMJOA) is an important subtype in the classification of temporomandibular disorders. TMJOA pathology is characterized by progressive cartilage degradation, subchondral bone remodeling, and chronic inflammation in the synovial tissue. However, the exact pathogenesis and process of TMJOA remain to be understood. An increasing number of studies have recently focused on inflammation and remodeling of subchondral bone during the early stage of TMJOA, which may elucidate the possible mechanism of initiation and progression of TMJOA. The treatment strategy for TMJOA aims at relieving pain, preventing the progression of cartilage and subchondral bone destruction, and restoring joint function. Conservative therapy with nonsteroidal anti-inflammatory drugs, splint, and physical therapy, such as low-energy laser and arthrocentesis, are the most common treatments for TMJOA. These therapies are effective in most cases in relieving the signs and symptoms, but their long-term therapeutic effect on the pathologic articular structure is unsatisfactory. A treatment that can reverse the damage of TMJOA remains unavailable to date. Treatments that prevent the progression of cartilage degradation and subchondral bone damage should be explored, and regeneration for the TMJ may provide the ideal long-term solution. This review summarizes the current understanding of mechanisms underlying the pathogenesis and treatment of TMJOA.