How to Manage "Closed Lock" Disc Displacement Without Reduction With Limited Opening

"Closed lock:" disc displacement without reduction with limited opening

• Functional disorder of the temporomandibular joint (TMJ) included within the broad category of derangements of the condyle disc complex.
• In the closed-jaw position, the disc is anterior to the condylar head, and the disc does not reduce with jaw opening. Medial and lateral displacement of the disc may also be present. This disorder is associated with limited jaw opening because the disc mechanically obstructs translation of the condyle.
• Derangements of the condyle disc complex are considered a subgroup of temporomandibular disorders (TMDs)

Presentation

Population

• More common in young and middle-aged adults.
• Approximately twice as common in women than men.
• Often remitting, self-limiting or fluctuating over time.
• Disc displacement without reduction with limited opening is relatively uncommon.
• Progression to chronic and disabling intracapsular TMJ disease is uncommon.

Signs

• Maximum assisted opening (passive stretch) is less than 40 mm, including the vertical incisal overlap.
• Deflection of the mandible to the ipsilateral (involved joint) side on opening and protrusion.
• Restriction of movement to the contralateral (normal joint) side.
• No intracapsular sounds (click or pop) identified unless chronic and associated with change in bony surfaces.

Symptoms

• Patients often report:
• Precisely when the "closed lock" occurred and can relate it to a specific event.
• History of intracapsular sounds (click or pop), but this sound has ceased.
• Pain may or may not be present. If present, pain is often localized to the preauricular area.
• Pain may be described as sharp, sudden and (sometimes) intense and is closely associated with joint movement, particularly at the point of limitation of movement.
• If inflammation develops, the pain may be constant, dull or throbbing, even at rest, and be accentuated by joint movement and joint loading.
• Patient displays concern regarding the sudden decrease in mandibular movement as a result of the "closed lock."

Investigation

1. Obtain thorough medical and dental history, including details related to pain and dysfunction.
2. Perform head and neck examinations (cranial nerve, muscle and joint tenderness, joint sound, range of motion of jaw) and intraoral (teeth, gingiva, oral soft tissue) to rule out local pathology or other sources of pain and to assess joint function.
3. Downward force applied to the mandibular incisors produces minimal, if any, increase in range of opening (hard end feel).
   1. Restricted mouth opening (maximum interincisal opening) as a result of muscle disorders is usually variable in terms of range of opening. However, mild passive force applied to the mandibular incisors will usually result in an increase in range of opening (soft end feel).
4. Loading of the involved joint is often painful.
5. Confirm the diagnosis on a magnetic resonance imaging (MRI) scan of the TMJ.
   1. In the maximal intercuspal position, the posterior band of the disc is located anterior to the 11:30 position and intermediate zone of the disc is anterior to the condylar head.
   2. On full opening, the intermediate zone of the disc is located anterior to the condylar head.
6. Determine whether the disc displacement without reduction with limited opening (closed lock) is acute or chronic.
   1. The clinical picture becomes less clear if disc displacement is chronic, as the ligaments become further elongated and the morphology of the disc becomes altered, thus allowing a greater range of movement. This may mistakenly be considered as a disc displacement without reduction without limited opening.

Diagnosis

A diagnosis of disc displacement without reduction with limited opening is based upon patient history, clinical examination and related tests.

Differential Diagnosis

• Common conditions
  • Masticatory myalgia
  • Myositis
  • TMJ osteoarthritis (degenerative joint disease)
  • Temporalis tendonitis
• Less common conditions
  • TMJ ankylosis
  • Coronoid hyperplasia
  • Tendon/muscle contracture
  • Synovial chondromatosis
  • Capsular fibrosis
  • Polyarthritides
  • Connective tissue disorders
  • Neoplasm
  • Trauma/fracture

Treatment

Approaches to acute cases may be different from chronic cases.

Common Initial Treatments

Acute cases

• Patient experiencing closed lock for 1 week or less.
• Consider referring the patient to an oral medicine specialist or oral and maxillofacial surgeon.
• Consider attempting manual manipulation to regain the normal disc–condyle relationship. If this is successful, then the patient could wear an anterior positioning appliance for the first 2–4 days followed by nighttime use only. Once stability has occurred, a stabilization appliance may be considered for nighttime use.
• If patient's condition is not responding to the above recommendations, then a minimal invasive surgical procedure (arthrocentesis/arthroscopy) could be considered to return the disc to a normal functional relationship with the condyle. This will need to be followed by conservative supportive therapies.
• Conservative supportive therapies:
• Advise the patient to avoid chewing/biting hard foods, stop parafunctional habits (tooth clenching and grinding, gum chewing, nail biting) and generally avoid activities that aggravate the condition.
• Counsel the patient to perform gentle, controlled jaw exercises within a pain-free range, as this may be helpful in regaining range of opening.
• Consider application of moist heat or ice to symptomatic preauricular area. After an acute injury (<72 hours) heat should not be used.
• Prescribe a short course of NSAIDs for pain control and resolution of inflammation.
• Fabricate a stabilization appliance for nighttime use.
• Involve a physical therapist knowledgeable in TMDs to assist with pain control and regaining range of opening.

Chronic cases

• Refer the patient to an oral and maxillofacial surgeon if he/she presents with a chronic "closed lock" and if previously applied conservative supportive therapies have failed. The oral and maxillofacial surgeon will explore definitive surgical approaches.
• Involve a physical therapist knowledgeable in TMDs to assist with pain control and regaining range of opening.

Alternate Treatments

• An auriculotemporal nerve block may be attempted to differentiate a primary diagnosis of joint pain from muscle pain.

Advice

• Patients are managed following principles of orthopedic, musculoskeletal and rehabilitative medicine that require experience in management of TMDs. 
• Patients need to be educated about this condition, as many patients attempt to force their mouths to open wider, thus aggravating the intracapsular tissues and potentially producing more pain.
• Patients need to be reassured that the long-term consequences of this condition are minimal, with the majority of patients regaining at least some of their original range of opening.

THE AUTHORS

	Dr. Klasser is associate professor, Louisiana State University School of Dentistry, department of diagnostic sciences, New Orleans, LA, USA.
	Dr. Epstein is consulting staff in the division of otolaryngology and head and neck surgery at the City of Hope Comprehensive Cancer Center in Duarte, California, and Cedars-Sinai Medical Center in Los Angeles, and maintains an oral medicine practice in Vancouver, British Columbia (Oralmedicinepacific.com).

Correspondence to: Dr. Gary D. Klasser, Louisiana State University School of Dentistry, department of diagnostic sciences, 1100 Florida Ave., Box 140, New Orleans, LA 70119, USA. Email: gklass@lsuhsc.edu.

The authors have no declared financial interests.

This article has been peer reviewed.