Methylprednisolone Injection for Lock Jaw (Trismus)
Methylprednisolone injection is NOT recommended as a treatment for lock jaw (trismus) caused by inflammatory temporomandibular joint (TMJ) disorders, except in very specific circumstances: it may be considered only in skeletally mature patients with confirmed inflammatory TMJ arthritis on MRI who have failed all conservative treatments, and even then, only as an intra-articular injection into the TMJ itself—not as an intramuscular or systemic injection. 1
Why Methylprednisolone Is Not First-Line Treatment
The Evidence Against Systemic/IM Steroids for Trismus
Research shows no benefit: Multiple studies demonstrate that intramuscular methylprednisolone injections (whether into the masseter or gluteal muscle) do not reduce trismus after oral surgery. 2
Surgical trismus studies are negative: Even in post-surgical settings where inflammation is acute and predictable, methylprednisolone shows no significant advantage over NSAIDs for trismus reduction. 3, 4, 5
One study showed modest benefit only in combination: A 2017 study found that combined methylprednisolone plus NSAIDs was superior to either alone, but this was for post-surgical prophylaxis, not treatment of established trismus. 4
What Guidelines Actually Recommend
For inflammatory TMJ arthritis causing trismus, the treatment hierarchy is clear:
First-line: Optimal systemic immunosuppressive therapy should be considered for active TMJ arthritis, as this may reduce long-term sequelae including trismus. 1
Conservative management is mandatory first: Jaw exercises, manual trigger point therapy, cognitive behavioral therapy, and jaw mobilization techniques all provide substantial pain relief and functional improvement. 6
NSAIDs are preferred over steroids for initial pharmacological management of TMJ pain and inflammation. 7
When Intra-Articular Steroids Might Be Considered
Skeletally Mature Patients Only
Intra-articular glucocorticoid injection may be indicated in skeletally mature patients with active TMJ arthritis confirmed on MRI and orofacial symptoms who have had inadequate response to other treatment modalities. 1
The effects are temporary and not curative, so this is not a definitive solution even when appropriately used. 1
Skeletally Immature Patients: Strong Contraindication
Intra-articular glucocorticoids are NOT recommended as first-line treatment in skeletally immature patients due to risks of mandibular growth suppression and intra-articular calcifications. 1
Repeated glucocorticoid injections are explicitly not recommended in growing patients. 1
The Correct Treatment Algorithm for Lock Jaw
Phase 1: Initial Conservative Management (0-12 weeks)
Jaw exercises and stretching provide approximately 1.5 times the minimally important difference in pain reduction. 6
Manual trigger point therapy provides nearly twice the minimally important difference in pain reduction. 6
Cognitive behavioral therapy provides substantial pain reduction when psychological factors contribute. 6
Jaw mobilization techniques improve joint mobility and reduce pain. 6
NSAIDs are recommended for pain and inflammation control. 6, 7
Patient education about soft diet, heat/cold therapy, and avoiding aggravating activities is essential. 6
Phase 2: Second-Line Options (12-24 weeks if inadequate response)
Occlusal splints may be beneficial specifically for patients with bruxism. 6, 7
Acupuncture shows moderate evidence of effectiveness. 6
Manipulation techniques may benefit some patients. 6
Phase 3: Refractory Cases (After 6 months of conservative treatment)
Arthrocentesis (joint lavage without steroids) is recommended before considering steroid injections. 7, 8
Intra-articular glucocorticoid injections should be considered only after failure of all conservative measures, and only in skeletally mature patients with confirmed inflammatory arthritis on MRI. 1, 7
Critical Pitfalls to Avoid
Do not use intramuscular or systemic methylprednisolone for trismus—the evidence shows no benefit. 2
Do not proceed to invasive procedures like steroid injections before exhausting conservative options for at least 6 months. 8
Do not use intra-articular steroids in skeletally immature patients as first-line treatment due to growth suppression risks. 1
Do not repeat glucocorticoid injections in growing patients. 1
Do not neglect the underlying cause: If trismus is due to inflammatory TMJ arthritis (especially in juvenile idiopathic arthritis), systemic disease-modifying therapy is needed, not just local steroid injections. 1