What is the diagnosis and treatment for an adult patient with a history of repetitive strain or injury to the elbow, possibly with underlying conditions such as diabetes or rheumatoid arthritis, presenting with numbness, tingling, and weakness in the hand and arm, suspected to have cubital tunnel syndrome?

Cubital Tunnel Syndrome: Diagnosis and Management

Clinical Diagnosis

Cubital tunnel syndrome is diagnosed clinically through physical examination demonstrating numbness and tingling in the ring and small fingers, with confirmation by nerve conduction studies when needed. 1, 2

Key Diagnostic Features

• Sensory symptoms: Numbness and tingling in the ring and 5th finger are the earliest and most common presenting signs 2
• Motor symptoms: Clumsiness, hand weakness, and atrophy of the first dorsal interosseous muscle occur with chronic compression 2
• Pain patterns: Point tenderness at the medial elbow and pain along the ulnar nerve distribution 2
• Age-related presentations: Older patients typically present with chronic motor symptoms, while younger patients have more acute sensory symptoms 2

Physical Examination Maneuvers

• Tinel's sign at the cubital tunnel (tapping over the ulnar nerve) 2
• Flexion-compression test: Symptoms reproduced with elbow flexion beyond 90 degrees 1, 2
• Palpation of the ulnar nerve for thickening and local tenderness 2
• Dynamic assessment: Ulnar nerve subluxation visible or palpable with elbow flexion/extension 3

Diagnostic Imaging and Studies

Initial imaging should begin with plain radiographs of the elbow to rule out osseous pathology, heterotopic ossification, or occult fractures. 3, 4

For nerve-specific evaluation:

• Dynamic ultrasound is the preferred initial diagnostic modality to directly visualize ulnar nerve subluxation during elbow flexion 1
• MRI with T2-weighted neurography serves as the reference standard if ultrasound is inconclusive, showing high signal intensity and nerve enlargement 5, 3
• Electromyography and nerve conduction studies confirm the diagnosis in atypical presentations and differentiate demyelinating from axonal injury 1

First-Line Conservative Management

Conservative treatment for 3-6 months is mandatory for patients without significant motor weakness or muscle atrophy before considering surgery. 1

Activity Modification (Most Critical)

• Maintain neutral forearm position when the arm is at the side to minimize nerve tension 1
• Avoid elbow flexion beyond 90 degrees to reduce compression and subluxation risk 1
• Apply proper padding (foam or gel pads) at the elbow to prevent direct compression, ensuring padding is not too tight 1

Adjunctive Conservative Measures

• NSAIDs (oral or topical) for short-term pain relief (2-4 weeks), though they do not alter long-term outcomes 1, 4
• Cryotherapy with melting ice water through a wet towel for 10-minute periods, repeated multiple times daily 1
• Relative rest and activity modification to reduce repetitive loading while avoiding complete immobilization 1
• Night splints to maintain elbow extension during sleep 6, 7

Surgical Indications and Options

Surgery should be recommended when conservative treatment fails after 3-6 months, or immediately in patients presenting with motor weakness, muscle atrophy, or fixed sensory changes. 6

Surgical Technique Selection

Simple in situ decompression is the treatment of choice for primary cubital tunnel syndrome, extended at least 5-6 cm distal to the medial epicondyle. 6, 8

• In situ decompression (open or endoscopic) is preferred for uncomplicated cases and most post-traumatic presentations 6, 8
• Subcutaneous anterior transposition is indicated when ulnar nerve luxation is painful or when the nerve "snaps" back and forth over the medial epicondyle 6
• Submuscular transposition may be preferred in cases of scarring, as it provides a healthy vascular bed and soft tissue protection 6
• Anterior transposition is indicated in severe bone or tissue changes of the elbow, especially with cubitus valgus 6

Critical Pitfalls to Avoid

• Never use padding that is too tight, as this creates a tourniquet effect and paradoxically increases compression 1
• Do not proceed directly to surgery without a 3-6 month conservative trial unless significant motor weakness or muscle atrophy is present 1
• Avoid corticosteroid injections as first-line treatment—unlike tendinopathy, injections are not recommended as primary therapy for nerve compression 1, 3
• Do not allow elbow flexion greater than 90 degrees during the conservative period 1
• Ensure adequate proximal and distal mobilization during transposition procedures to prevent nerve kinking and compromised blood flow 6
• Always obtain initial radiographs to rule out osseous pathology before attributing symptoms solely to nerve entrapment 3, 4

Differential Diagnosis Considerations

When evaluating suspected cubital tunnel syndrome, consider:

• UCL injury: Pain with valgus stress testing and medial joint line tenderness (distinct from epicondyle) 3
• Medial epicondylitis: Tenderness directly over the medial epicondyle with resisted wrist flexion 3, 4
• Intra-articular pathology: Mechanical symptoms (locking, clicking, catching) and pain with passive range of motion 3
• C8 radiculopathy, Pancoast tumor, or pressure palsy in atypical presentations 6