Human Amniotic Membrane as an Interpositional Material in Temporomandibular Joint Arthroplasty for Intraarticular Pain and Dysfunction: A Randomized Clinical Trial.

BACKGROUND

Open arthroplasty with discectomy is offered for temporomandibular joint (TMJ) intraarticular pain and dysfunction after failed conservative care. Whether human amniotic membrane (HAM) interposition improves outcomes remains unclear.

PURPOSE: To compare pain, mandibular function, and safety between discectomy plus HAM and discectomy alone.

STUDY DESIGN, SETTING, AND SAMPLE: Single-center randomized trial (Treviso Regional Hospital, Italy; 2017 to 2024). Adults with TMJ osteoarthrosis on magnetic resonance imaging and symptoms persisting after 5 hyaluronic acid arthrocenteses were randomized at 1:1 ratio (block randomization and concealed allocation).

PREDICTOR VARIABLE: Reconstructive technique: discectomy plus HAM versus discectomy alone, randomly assigned.

PRIMARY OUTCOME VARIABLES: Peak pain on a 0 to 10 visual analog scale (VAS) at rest, phonation, and mastication; maximum interincisal opening (MIO, mm); lateral and protrusive excursions. Secondary: complications. Assessed at baseline (T0) and 12 months (T1).

COVARIATES: Age, sex, symptom duration, arthrocentesis cycles, unilateral versus bilateral disease, and follow up.

ANALYSES: Welch t-test, Mann-Whitney U, Fisher's exact test; analysis of covariance (ANCOVA) adjusting for baseline, age, sex, and laterality; P < .05; intention-to-treat.

RESULTS

Sixty-two subjects enrolled: 32 HAM (mean age 48.7 [standard deviation [SD] 17.4] years; 26 [81.3%] female) and 24 controls (mean age 60.3 [SD 11.2]; 14 [58.3%] female; P = .02 and P = .08). At T0, peak VAS was comparable at rest (4.38 [SD 1.18] vs 4.58 [SD 1.14]; P = .51) and phonation (6.47 [SD 1.08] vs 6.58 [SD 1.10]; P = .70); mastication was higher in controls (7.58 [SD 1.06] vs 6.53 [SD 1.29]; P = .002). At T1, peak VAS favored HAM at rest (0.88 [SD 0.83] vs 3.67 [SD 1.09]; P < .001), phonation (1.41 [SD 1.04] vs 5.62 [SD 1.13]; P < .001), and mastication (1.41 [SD 1.13] vs 4.58 [SD 0.83]; P < .001). MIO did not differ (34.34 [SD 4.60] vs 35.88 [SD 1.54] mm; P = .09). Right lateral excursion favored HAM (8.12 [SD 1.48] vs 6.08 [SD 0.78] mm; P < .001). Transient facial nerve weakness: 4 (12.5%) HAM versus 6 (25.0%) controls (P = .29); no other complications.

CONCLUSIONS AND RELEVANCE: HAM interposition yielded clinically meaningful pain reduction and superior excursive and masticatory outcomes at 12 months, with no benefit on MIO and no added morbidity.