The efficacy of intra-articular injectable platelet-rich fibrin application in the management of Wilkes stage III temporomandibular joint internal derangement

The aim of this retrospective study was to compare the effectiveness of hyaluronic acid (HA) and injectable platelet-rich fibrin (i-PRF) in the management of Wilkes stage III internal derangement, and to evaluate the biosupplementation capacity of i-PRF. The records of all 54 relevant patients with Wilkes stage III internal derangement confirmed by magnetic resonance imaging and treated with arthrocentesis alone or in combination with HA or i-PRF were selected. The outcome variables were pain intensity at rest (VASr) and in function (VASf), evaluated with a visual analogue scale, and maximum mouth opening (MMO), evaluated in millimetres; assessments were made preoperatively, immediately after the procedure, and at 1 week, 1 month, and 3 months postoperatively. When compared to the HA and arthrocentesis groups, the i-PRF group showed significantly better improvements in MMO at 1 and 3 months (P = 0.024 and P = 0.006, respectively), VASr at 1 and 3 months (both P < 0.001), and VASf at 1 week (P = 0.019) and 1 and 3 months (both P < 0.001) postoperatively. In all groups, better MMO, VASr, and VASf values were observed compared to the preoperative status. The application of i-PRF after arthrocentesis is more effective than arthrocentesis alone or with HA in the short term. HA was found not to provide significant additional benefits over arthrocentesis alone.     

Intraoperative comparison of single- and double-puncture techniques in temporomandibular joint arthrocentesis

The objective of this study was to compare techniques for temporomandibular joint (TMJ) arthrocentesis intraoperatively and to determine the ease of performance of these techniques for the physician. A total of 33 TMJ treatments were done using single-puncture arthrocentesis (SPA) type 1, SPA type 2, and double-puncture arthrocentesis (DPA) (n = 11 in each treatment group) between December 2013 and December 2017. A retrospective analysis of the duration of the procedure (minutes), occurrence of complications, number of cannula relocations, and ease of the procedure was performed. Ease of the procedure was measured using a Likert-type visual analogue scale (VAS; 0–10). All measurement variables were recorded intraoperatively, and related data were analyzed statistically. Significant differences were found between SPA type 2 and the other techniques in terms of procedure duration and ease of the procedure (P < 0.05). No significant differences were found in the occurrence of complications or number of cannula relocations between the techniques (P > 0.05). Compared to the other TMJ arthrocentesis techniques, SPA type 2 is easier, and physicians can perform it in a shorter time.     

Ultrasound-guided versus blind temporomandibular joint injections: a pilot cadaveric evaluation

Temporomandibular disorders are painful conditions that require precise injection therapy in selected patients. This pilot cadaveric study was undertaken to compare the accuracy of temporomandibular joint (TMJ) injection between the anatomical landmark-based (blind) technique and an ultrasound-guided technique. TMJ injections using the blind technique or the ultrasound-guided technique were performed in 10 non-embalmed cadavers. After dissection, the accuracy of the TMJ injections was found to be significantly greater for the ultrasound-guided injections than for the blind technique (blind 55% vs. ultrasound 95%, P = 0.008). For injections into the upper joint space of the TMJ, the success rate of the injection was comparable for the two techniques (blind 80% vs. ultrasound 100%, P = 0.474). However, ultrasound-guided injections into the lower joint space had a much higher success rate than the blind technique (blind 30% vs. ultrasound 90%, P = 0.020). The blind technique was associated with a considerable proportion of failed or inappropriate injections, especially for lower joint space injections. Ultrasound-guided TMJ injections were accomplished with a higher accuracy than the conventional blind technique, especially in the case of injections targeting the lower joint space of the TMJ.     

Relationship between temporomandibular joint pain and magnetic resonance imaging findings in patients with temporomandibular joint disorders

The purpose of this study was to evaluate abnormal magnetic resonance imaging (MRI) findings related to temporomandibular joint (TMJ) pain. This study included 245 joints of 152 patients with temporomandibular disorders with anterior disc displacement; of these, 129 joints had joint pain whereas 116 joints had no joint pain. MRI was used to evaluate the reduction of anterior disc displacement, joint effusion, mandible condylar morphology, bone marrow oedema of the mandibular condyle, and signal intensity of the posterior disc attachment (PDA) on fat-suppressed T2-weighted images. The odds ratio (OR) for each MRI variable for the pain group versus the no pain group was computed using logistic regression analysis. Univariate logistic regression analysis showed significant correlations between TMJ pain and all MRI findings. Multivariate logistic regression analysis showed significant correlations with joint effusion (P = 0.03, OR 2.21), bone marrow oedema (P < 0.001, OR 11.75), and signal intensity of the PDA (P < 0.001, OR 6.21). These results suggest that bone marrow oedema, high signal intensity of the PDA on fat-suppressed T2-weighted images, and joint effusion, in descending order of influence, are factors related to TMJ pain.     

Surgical complications related to temporomandibular joint arthroscopy: a prospective analysis of 39 single-portal versus 43 double-portal procedures

Temporomandibular joint (TMJ) arthroscopy is a minimally invasive surgical procedure proposed for diverse TMJ intra-articular disorders. A prospective study was designed with the aim of investigating intraoperative and postoperative surgical complications for single and double-portal TMJ arthroscopy. All interventions were performed by one surgeon with the same surgical protocol. A total of 55 patients were enrolled, resulting in 82 TMJ arthroscopies (28 unilateral and 27 bilateral). A total of 39 single portal (47.57%) and 43 double-portal (52.43%) arthroscopies were performed. No severe and irreversible complications were observed. Most complications were resolved after 4 weeks. Double-portal was associated with more complications (n = 23) compared with single-portal TMJ arthroscopy (n = 14), with a statistically significant difference found between single and double-portal TMJ arthroscopy in two intraoperative complications: intra-articular bleeding (P = 0.044) and oedema of the preauricular area (P = 0.042). This study confirms the safety of TMJ arthroscopy for single and double-portal procedures, with the authors suggesting a multicentre study, in an effort to minimize any possible bias.     

Effectiveness of treatment with viscosupplementation in temporomandibular joints with or without effusion

The objective of this study was to determine whether the effectiveness of viscosupplementation with hyaluronic acid (HA) in patients with temporomandibular joint (TMJ) degenerative disorders depends on the presence of intra-articular effusion. In this study of case–control design, two groups of 25 patients were recruited: patients with a clinical diagnosis of painful chronic TMJ osteoarthritis and magnetic resonance imaging (MRI) signs of TMJ degeneration, with (effusion group) or without (no effusion group) MRI evidence of TMJ effusion. All patients underwent five weekly single-needle arthrocenteses plus medium molecular weight HA and 6 months of follow-up. Several clinical outcome parameters were assessed. For all variables, analysis of variance (ANOVA) for repeated measures was performed to assess the existence of significant within-group and between-group treatment effects. Over time, both groups showed significant improvements in all outcome parameters, which were maintained at the 6-month follow-up (P < 0.05). Between-group comparisons showed that the treatment effects did not differ significantly for either the primary outcome variable (pain levels: F = 0.849, P = 0.548) or secondary outcome variables (chewing efficiency: F = 0.854, P = 0.544; functional limitation: F = 1.35, P = 0.226; mouth opening: F = 0.658, P = 0.707). The null hypothesis that there are no differences in treatment effectiveness between patients with and without effusion could not be rejected.     

Comparison of intraoperative outcomes with single and double puncture techniques of arthrocentesis of the temporomandibular joint

Evidence of differences in operator-related outcomes between single and double puncture arthrocentesis is limited. The purpose of this prospective study was to compare intraoperative outcomes with single puncture types 1 and 2, and double puncture, arthrocentesis. A total of 59 patients with 60 temporomandibular joints (TMJ) were treated sequentially by single puncture type 1 (n = 20), single puncture type 2 (n = 20), and double puncture arthrocentesis (n = 20). Total operating time, incidence of dislocation of the needle, preauricular swelling, and ease of operation were compared. Single puncture type 2 arthrocentesis took significantly less time than type 1 (p < 0.0001) or double puncture arthrocentesis (p < 0.0001), but there was no difference in operating time between single puncture type 1 and the double puncture technique (p = 0.25). There were significantly fewer dislocations of the needle with single puncture type 1 (p = 0.041) and single puncture type 2 (p = 0.033) than with double arthrocentesis. Single puncture type 2 arthrocentesis was easier than the single puncture type 1 (p = 0.001) or double puncture technique (p < 0.0001). Extravasation of fluid caused swelling in seven patients after double puncture, and in three patients each after single puncture types 1 and 2, arthrocentesis. Our results indicate that the single puncture type 2 technique is easiest and requires the least operating time. There was no difference between single puncture type 1 and double puncture arthrocentesis in terms of operating time or ease of the procedure. There were fewer operative dislocations of the needle with the single than with the double puncture technique.     

Neurosensory assessment in patients with total reconstruction of the temporomandibular joint

Somatosensory sensitivity and postoperative endogenous pain modulation have not been investigated in temporomandibular joint (TMJ) prosthesis patients. The objectives of this study were to assess somatosensory function at the TMJ and examine possible differences in conditioned pain modulation (CPM) between patients with total TMJ prostheses (n = 7) and a reference group of healthy controls (n = 20). Somatosensory abnormalities were assessed using quantitative sensory testing (QST), which encompasses thermal and mechanical testing procedures. CPM was tested by comparing pressure pain thresholds (PPT) before (baseline), during, and after the application of painful and non-painful cold stimuli. PPTs were measured at the TMJ and thenar eminence (control). The effect of CPM on PPT values was tested with analysis of variance. Three patients exhibited mixed somatosensory loss (i.e., decreased thermal and mechanical detection) with mixed hyperalgesia (i.e., increased sensitivity to thermal and mechanical pain) and two patients exhibited mixed loss with only mechanical hyperalgesia. There was a significant decrease in pressure pain sensitivity at both sites during painful cold application in healthy controls (P < 0.001) but not in patients (P = 0.476). In conclusion, QST measures demonstrated somatosensory abnormalities in patients with total TMJ prostheses. Noxious conditioning cold stimuli evoked CPM-like effects in healthy subjects but not in patients with TMJ reconstruction.     

Comparison of the outcomes of three surgical treatments for end-stage temporomandibular joint disease

The aim of this study was to determine whether there are any differences between condylectomy, rib grafts, and prosthetic joints (Biomet TMJ stock prosthesis) with regard to outcomes for patients with end-stage temporomandibular joint (TMJ) disease. Fifty-six of a total 127 patients who presented with category 5 end-stage TMJ disease over 3 years (2010–2013) agreed to participate in this retrospective, comparative, cohort study. Patients were divided into four groups: preoperative (n = 16), condylectomy (n = 8), rib graft (n = 16), and prosthetic joint (n = 16). They were assessed for major postoperative complications (i.e., return to theatre) and maximum range of mandibular motion, and all completed a specific quality of life (QOL) questionnaire. Whilst the condylectomy group demonstrated the best mandibular range of motion (P < 0.01), rib graft patients were more likely to experience complications (43.8%) necessitating a return to theatre. The prosthesis group recorded the best mean aggregate QOL score, but the difference compared to the rib graft and condylectomy groups was not statistically significant. The results of this study suggest that for dentate patients, prosthetic joints are highly dependable with no returns to theatre and favourable QOL outcomes. For edentulous patients, condylectomies alone also appear to work well. Future TMJ prosthetic designs should focus on improving mandibular range of motion, as the current stock prosthesis allows only a restricted range, no better than that achieved with rib graft (P > 0.05) and far less than that achieved with condylectomy (P < 0.01).     

Temporal bone pneumatization in patients with dentofacial deformities: cone beam computed tomography study

Pneumatization in the osseous components of the temporomandibular joint (TMJ) may represent a complicating factor in TMJ surgery. This study determined the prevalence and characteristics of pneumatized articular eminence (PAE) and pneumatized glenoid fossa (PGF) using cone beam computed tomography (CBCT) scans of patients with and without dentofacial deformities. The CBCT of 587 asymptomatic patients (216 class I, 179 class II, 192 class III) were assessed to determine PAE and PGF. Age, sex, laterality, and type (uni/multilocular) of pneumatization were recorded. Differences were tested using the χ² test and binary logistic regression models (P < 0.05). Overall, 63.7% of patients presented some pneumatization: 15.5% presented both PAE and PGF, 0.9% presented only PAE, and 47.4% presented only PGF. The multilocular type was more frequent in both PAE and PGF (P < 0.001). There was a significant difference regarding dentofacial deformity for PAE (P = 0.021), with a higher frequency in class I. There were no differences according to sex, age, or laterality. The absence or lower frequency of pneumatization in class II and III patients may indicate continuous remodelling of the joint, which is submitted to abnormal occlusion forces. This knowledge is helpful for TMJ surgery planning, particularly as patients with dentofacial abnormalities may more often be candidates for TMJ surgery.     

The action of anti-inflammatory agents in healthy temporomandibular joint synovial tissues is sex-dependent

This study evaluated the effects of dexamethasone, parecoxib, and glucosamine on cartilage thickness and cytokine levels in the temporomandibular joint (TMJ). Forty-eight rats (24 female, 24 male) were assigned to four treatments administered once daily for 7 days: control (saline intramuscularly), parecoxib (0.3 mg/kg intramuscularly), dexamethasone (0.1 mg/kg intramuscularly), and glucosamine (80 mg/kg orally). The thickness of TMJ cartilage and levels of four cytokines were measured. Median cartilage thickness was higher in males than in females in the control (253.2 vs. 240.4 μm, P = 0.0036), parecoxib (227.3 vs. 192.1 μm, P < 0.0001), and dexamethasone (227.1 vs. 170.5 μm, P = 0.017) groups, but was lower in males in the glucosamine group (214.5 vs. 239.6 μm, P = 0.0001). IL-1β was not detected. Median IL-1α levels differed between males and females in the parecoxib group (0.08 vs. 0.04 ng/ml, P = 0.0055), but not in the control (0.07 vs. 0.06 ng/ml), dexamethasone (0.06 vs. 0.04 ng/ml), or glucosamine (0.08 ng/ml vs. 0.06 ng/ml) groups (all P > 0.05). Only dexamethasone induced lower IL-6 levels in males than in females (median 4.6 vs. 2.1 ng/ml, P = 0.0044). Median TNF-α levels did not differ between males and females in the control (0.07 vs. 0.05 ng/ml) or parecoxib (0.07 vs. 0.05 ng/ml) groups (both P > 0.05), but dexamethasone (0.09 vs. 0.05 ng/ml, P = 0.0002) and glucosamine (0.09 vs. 0.07 ng/ml, P = 0.0259) induced higher TNF-α levels in females. Thus, the effects of the three treatments on the levels of cytokines and thickness of condylar cartilage were sex-dependent.     

Study on the lateral pterygoid muscle status after artificial temporomandibular joint replacement

The purpose of this study was to explore the status of the lateral pterygoid muscle (LPM) after detachment in artificial temporomandibular joint replacement (TJR) surgery. Patient clinical and computed tomography imaging data were collected before and after unilateral artificial TJR with LPM detachment. The volume of the LPM on the operated and unoperated sides was measured before and after surgery (at 1, 3, 6, 12 months) using ProPlan CMF 3.0 software. The volumes of the LPM on both sides, the patient’s mandibular movements, quality of life (QoL), and pain and diet scores (visual analogue scales) were evaluated and compared at the different follow-up stages. Ten patients were included in the study. After surgery, the volume of the operated LPM was significantly reduced to 60.78% at 3 months (P = 0.007), and gradually stabilized to 51.58% at 6 months (P = 0.025) and 54.68% at 1 year postoperative (P = 0.002). There were no significant LPM volume changes on the unoperated side (P = 0.67). Lateral movement of the operated joint was significantly reduced (P = 0.021) and correlated with the LPM volume change after surgical detachment (P = 0.042). The LPM shrank after detachment in the artificial TJR surgery and the muscle detachment affected the movement of the replaced joint.     

The effect of omega-3 in temporomandibular joint synovial tissues of rats with induced arthritis: pilot study

This study evaluated the effect of systemic administration of omega-3 on the expression of interleukins IL-1β and IL-10 and tumour necrosis factor alpha (TNF-α) and on the thickness of cartilage in the temporomandibular joint (TMJ) inflammatory model induced by complete Freund’s adjuvant (CFA). Thirty-two adult rats were divided equally into four groups: control, CFA (induced arthritis), and induced arthritis animals treated with dexamethasone or omega-3. The TMJs were then removed and assigned to histomorphometric analysis or immunoassay. The Kruskal–Wallis test with Dunn post hoc test was applied to the data; the significance level was set at 5%. IL-1β levels (median; interquartile range) were higher (P < 0.0001) in the CFA group (46.4 ng/ml; 39.4–53.3) than in the control group (1.81 ng/ml; 1.5–5.4), but there were no differences between the control, omega-3, and dexamethasone groups. TNF-α levels were also higher (P < 0.0001) in the CFA group (122.7 ng/ml; 92.9–284.7) than in the control group (29.1 ng/ml; 23.7–31.3). IL-10 levels were lowest (P < 0.0001) in the CFA group (73.5 ng/ml; 52.8–90.5), and no differences were found amongst the other groups. In conclusion, omega-3 successfully reduced the damage in the TMJ of induced arthritis rats. Further investigations are warranted to confirm whether the administration of omega-3 has a comparable effect to glucocorticoids in rheumatoid arthritis patients.     

Efficiency of arthrocentesis treatment for different temporomandibular joint disorders

This study was performed to determine whether arthrocentesis therapy has different outcomes in three groups of patients with different temporomandibular disorders (TMDs). A clinical trial was conducted including 45 patients with 45 unilaterally affected joints divided into three groups (n = 15): osteoarthritis (OA), disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR). All patients underwent the same arthrocentesis treatment protocol. The outcome variables, including visual analogue scale evaluations and measurements of mandibular motion (in millimetres), were recorded at baseline and at 1 and 6 months postoperative. Inter-group assessments showed significant short-term differences in joint sounds (P = 0.016) and significant long-term differences in masticatory efficiency (P = 0.046) and protrusive movement (P = 0.048). The estimation of mean changes between baseline and long-term follow-up revealed significant differences in joint sounds (P < 0.001), disruption in daily activities (P = 0.002), maximum mouth opening (P = 0.008), and protrusive movement (P = 0.002) between the groups. Arthrocentesis therapy may be useful to improve clinical symptoms and range of mandibular movement in patients with all three types of TMD. However, the benefit of arthrocentesis may be greater for patients with DDWoR than for those in the other groups.     

Is there a correlation between arthroscopic findings and the clinical signs and symptoms of patients with internal derangement of the temporomandibular joint? A prospective study

The aim of this study was to evaluate the correlation between clinical signs and symptoms of patients with internal derangement of the temporomandibular joint (TMJ) and arthroscopic findings. The study included a sample of 67 patients who underwent TMJ arthroscopy. The variables evaluated were the arthroscopic findings of synovitis, chondromalacia, adhesion, and roofing. The Spearman correlation index was used to correlate these findings with the clinical signs and symptoms of internal derangement of the TMJ, namely maximum mouth opening, pain (visual analogue scale, VAS), and the Wilkes classification. The mean age of the population was 36.16 years, and 85% were female. There was a correlation between pain and synovitis (P = 0.0029, r = 0.3508), between mouth opening limitation and the amount of adhesion (P = 0.0004, r = ?0.4084), and between Wilkes classification and the presence of chondromalacia and disc displacement (P = 0.001, r = 0.374 and P = 0.0045, r = ?0.3357, respectively). No correlation was found between age and the presence of chondromalacia (P = 0.3444, r = 0.1147). Patients who had worse pain symptoms had more advanced stages of synovitis, and the increased presence of adhesions was associated with limitations in mouth opening. Furthermore, those with more advanced Wilkes stages had greater disc displacement and more severe stages of chondromalacia.     

Hearing changes after temporomandibular joint arthroscopy: a prospective study

Temporomandibular Joint (TMJ) arthroscopy is considered an effective and safe minimally invasive surgical approach. While the long-term outcomes of arthroscopy tend to be positive and free of secondary effects, patients occasionally complain about their hearing following the treatment. The aim of this prospective study was to investigate possible hearing changes associated with TMJ arthroscopy. Pure-tone audiograms were performed in patients two weeks before TMJ arthroscopy and repeated six weeks after intervention. A total of 15 patients (mean age of 41.73 ± 16.36) were enrolled; 25 TMJ arthroscopies were performed (five unilateral and ten bilateral). Statistically significant differences were found between preoperative and postoperative audiograms in the frequencies 256 Hz (P = 0.011) and 8 kHz (P = 0.058, borderline). For the frequency 256 Hz the difference was favourable, but not superior to 5 dB. For the frequency 8 kHz, in three patients the TMJ arthroscopy resulted in a decrease of 10 dB. However, no clinical hearing changes or complaints were observed in the involved patients. No differences in audiograms between level 1 or 2 arthroscopy were observed. The study reinforces the safety of the TMJ arthroscopy level 1 and 2 with the reported protocol. The authors recommend larger studies to validate the results, specially for frequency 8 kHz.     

Costochondral grafting for paediatric temporomandibular joint reconstruction: 10-year outcomes in 55 cases

Costochondral grafting (CCG) can be used for the reconstruction of ankylotic, hypoplastic, and resected temporomandibular joint (TMJ) defects. CCGs have previously been considered the gold standard in children due to their growth potential and autogenous origin, but the disadvantages are unpredictable growth and joint ankylosis. This was a retrospective study of all children who received CCGs for TMJ reconstruction from 1985 to 2004, to allow a 10-year follow-up. Fifty-five patients were included in this study, with 74 grafts being placed; their mean age was 7.9 ± 4.2 years. Infection-related ankylosis (18.2%) and craniofacial microsomia (16.4%) were the most common diagnoses. Overall, 58.2% of patients suffered one or more complications over the follow-up period, with ankylosis (32.7%) and overgrowth (16.4%) being most common. There was a significant correlation between those with infection-related ankylosis and subsequent complications (χ² = 8.8, df = 1, P < 0.005), while ankylotic patients in general exhibited greater overall complication rates (χ² = 9.0, df = 1, P < 0.005). Patients with congenital TMJ defects were more likely to be complication-free than those with acquired defects (χ² = 4.0, df = 1, P < 0.05). Caution is advised when placing CCGs in paediatric patients with ankylosed TMJs, especially those with infection-related ankylosis.     

Effects of four treatment strategies for temporomandibular joint closed lock

A previous randomized controlled trial (RCT) by Schiffman et al. (2007)¹⁵ compared four treatments strategies for temporomandibular joint (TMJ) disc displacement without reduction with limited mouth opening (closed lock). In this parallel group RCT, 106 patients with magnetic resonance imaging (MRI)-confirmed TMJ closed lock were randomized between medical management, non-surgical rehabilitation, arthroscopic surgery, and arthroplasty. Surgical groups also received rehabilitation post-surgically. The current paper reassesses the effectiveness of these four treatment strategies using outcome measures recommended by the International Association of Oral and Maxillofacial Surgeons (IAOMS). Clinical assessments at baseline and at follow-up (3, 6, 12, 18, 24, and 60 months) included intensity and frequency of TMJ pain, mandibular range of motion, TMJ sounds, and impairment of chewing. TMJ MRIs were performed at baseline and 24 months, and TMJ tomograms at baseline, 24 and 60 months. Most IAOMS recommended outcome measures improved significantly over time (P ≤ 0.0003). There was no difference between treatment strategies relative to any treatment outcome at any follow-up (P ≥ 0.16). Patient self-assessment of treatment success correlated with their ability to eat, with pain-free opening ≥35 mm, and with reduced pain intensity. Given no difference between treatment strategies, non-surgical treatment should be employed for TMJ closed lock before considering surgery.     

Predictive factors in temporomandibular joint arthroscopy: a prospective cohort short-term outcome study

Improving the outcomes of surgical treatment of the temporomandibular joint (TMJ) is beneficial from a patient and health-economy perspective. Optimizing conditions for a successful result can be reached using validated, strict diagnostic criteria and by identifying patient-specific factors predicting the outcome. The aim of this study was to investigate possible predictive factors in TMJ arthroscopy. A prospective cohort study including 93 patients undergoing arthroscopy was conducted. The outcome was graded as successful (53%, n = 49), good (25%, n = 23), intermediate (20%, n = 19), or deteriorated (2%, n = 2) using a predefined set of objective and subjective outcome measures. The outcome was correlated with preoperative and perioperative variables and the diagnosis. Preoperative bilateral masticatory muscle tenderness on palpation was the only variable significantly correlated with a negative outcome in the adjusted regression analysis (odds ratio (OR) 2.56, P = 0.048). Low age (OR 1.03, P = 0.05) and bilateral joint surgery/operated side (OR 0.24, P = 0.05) were found to correlate with an unsuccessful outcome in the unadjusted analysis. Eighty-nine percent of the patients with osteoarthritis benefited from arthroscopy, while corresponding figures were 80% for disc displacement without reduction and 64% for chronic inflammatory arthritis. Preoperative bilateral masticatory tenderness might be a useful predictive factor suggesting the consideration of revised non-invasive therapy before surgery.