How should I evaluate and manage a patient presenting with crepitus?

Evaluation and Management of Crepitus

The evaluation of crepitus depends entirely on its anatomic location: soft-tissue crepitus in the extremities requires immediate radiographs to detect gas and rule out necrotizing fasciitis, while articular crepitus (joint popping/grinding) is typically benign but may indicate underlying osteoarthritis requiring further assessment.

Immediate Assessment: Distinguish Soft-Tissue from Articular Crepitus

Soft-Tissue Crepitus (Medical Emergency)

• Obtain plain radiographs immediately as the first study when soft-tissue gas is suspected, as they are well-suited for detecting gas in extremities and juxta-articular tissues 1
• Elicit a history of recent surgical intervention, trauma (subcutaneous emphysema), or puncture wound 1
• In the absence of recent surgery, trauma, or puncture wound, soft-tissue gas is a reliable indication of infection and requires urgent surgical consultation 1
• Gas in the deep fascial planes is a hallmark of necrotizing fasciitis, which is rapidly progressive and life-threatening 1

Critical Action: If radiographs show soft-tissue gas without a clear traumatic or surgical cause, proceed immediately to CT imaging and surgical consultation 1

CT Imaging for Soft-Tissue Gas

• CT is the most sensitive means of detecting soft-tissue gas and can delineate extent and compartmental location 1
• CT demonstrates fascial thickening, fluid collections along deep fascial planes, and intermuscular septal edema that indicate necrotizing fasciitis 1
• MRI is less sensitive than CT for detecting soft-tissue gas, though gradient-echo sequences can identify air through susceptibility artifact 1

Articular Crepitus: Joint-Based Assessment

Knee Crepitus

• Articular crepitus (joint grating or popping) is most commonly associated with arthritis 1
• Crepitus predicts incident symptomatic knee osteoarthritis in a dose-dependent manner, with odds ratios increasing from 1.5 (rarely) to 3.0 (always) compared to never experiencing crepitus 2
• Obtain standing anteroposterior and lateral knee radiographs to assess for Kellgren-Lawrence grade ≥2 osteoarthritis 2
• Crepitus is associated with osteophytes at the patellofemoral and lateral tibiofemoral joints, and with meniscal tears 3
• At the medial tibiofemoral compartment, crepitus correlates with osteophytes and medial collateral ligament pathology 3

Post-Surgical Knee Crepitus

• Patellofemoral crepitus after total knee arthroplasty has an incidence of 0-18% and results from peripatellar fibrosynovial hyperplasia 4
• Most patients are unaware or have minimal symptoms requiring no treatment 4
• If significant disability occurs, arthroscopic debridement eliminates symptoms in a high percentage of patients 4

Scapulothoracic Crepitus

• Scapulothoracic crepitus produces grinding or snapping noise with scapular motion, often accompanied by pain 5
• May be due to pathologic changes in bone or soft tissue between the scapula and chest wall, or changes in scapulothoracic congruence from scoliosis or thoracic kyphosis 5
• Begin with postural and scapular strengthening exercises plus local modalities (heat, ice, NSAIDs) 5
• Conservative treatment is highly effective when soft-tissue lesions are the cause 5
• Consider partial scapulectomy or bursectomy (open or arthroscopic) only after failed conservative treatment or when osseous lesions are identified 5

Management Algorithm

For Soft-Tissue Crepitus:

1. Obtain plain radiographs immediately 1
2. If gas is present without clear trauma/surgery history → CT scan + immediate surgical consultation 1
3. If necrotizing fasciitis is suspected → emergent surgical debridement 1

For Articular Crepitus:

1. Obtain weight-bearing radiographs of the affected joint 3, 2
2. If osteoarthritis is present → initiate conservative management (NSAIDs, physical therapy, weight loss if applicable) 3
3. If symptoms are severe or progressive → consider MRI to assess cartilage, menisci, ligaments, and bone marrow lesions 3
4. Counsel patients that subjective crepitus identifies them as at-risk for developing symptomatic osteoarthritis, particularly if radiographic changes are already present 2

Common Pitfalls to Avoid

• Never dismiss soft-tissue crepitus as benign without imaging, as necrotizing fasciitis can be rapidly fatal 1
• Do not assume all joint crepitus is benign; it predicts future symptomatic osteoarthritis and warrants baseline imaging 2
• Knuckle cracking (tribonucleation) is benign and does not require intervention 6
• Most patients with post-arthroplasty crepitus do not require treatment unless significant disability is present 4