Cubital Tunnel Syndrome
Ulnar nerve entrapment (compression or irritation) at the medial side of the elbow leads to cubital tunnel syndrome. Numbness & tingling in the hand & fingers along the course of ulnar nerve are common symptoms of this syndrome. In worse conditions, cases may progress to loss of function of the hand.
Cubital tunnel is formed by cubital retinaculum which is about 4mm in length present between the olecranon & medial epicondyle. Floor is formed by medial collateral ligament & ulnar nerve. At the cubital tunnel, the ulnar nerve passes between the two heads of flexor carpi ulnaris muscle. Elbow movement, puts the ulnar nerve to slide & stretch through the cubital tunnel.
This unusual anatomy of the cubital tunnel and the well‐recognised increase in intraneural pressure associated with elbow flexion are believed to be key issues in the pathogenesis of cubital tunnel syndrome.
The tunnel changes from oval to elliptical during elbow flexion. Also, wrist & finger extension along with shoulder abduction & elbow flexion places extra strain on the ulnar nerve.
PATHOPHYSIOLOGY:
Compression, traction & fraction have been implicated in Cubital tunnel syndrome:
- Compression- Direct blow/ trauma to the elbow or indirect compression of intrinsic blood vessel of the nerve causing ischaemia. Compression interferes with axonal transport pathways.
- Traction- Previous injuries to the nerve may tether it to the walls of the tunnel, thus preventing normal sliding and expose it to traction injuries.
- Friction- Tight tunnel predisposes the nerve to friction & compression.
SYMPTOMS:
- Pain at the elbow &/ or radiation to the forearm & digits, during initial stage
- Altered sensation in little & ring finger, sensory loss (Tingling, numbness or burning)
- Weakness in arm, forearm or fingers
- Weakened grip strength
- Difficulty manipulating things with hand & fingers
- Ulnar innervated muscle atrophy in extreme severe cases
SIGNS:
- Froment’s sign (clawing of the ulnar innervated digits- ring & little finger)
- Wartenberg’s sign- Abduction of little finger
- Valgus deformity while extending the elbow
- Positive tinnel’s sign over cubital tunnel
INVESTIGATIONS:
- Nerve conduction studies
- Elbow XRAY- Shows OA, Cubitus valgus deformity, calcification in medial collateral ligament.
- MRI, US- Show presence of lesions such as ganglions, neuromas or aneurysms within Guyons tunnel
- Physical Exam- Check for tenderness & location of pain, check muscle strength for wrist & finger flexion
TREATMENT:
- Medications-NSAIDs to reduce pain & swelling
- Physical Therapy- Focussing on flexor compartment of elbow & wrist, increasing grip strength, stretching the flexor & extensor origin of the elbow, gliding the nerve through the canal by performing ulnar nerve glides.
- Splints/ braces for the elbow
- Rest & ice packs- Avoid activities that trigger episodes of pain & apply packs of ice to painful area for 10mins,2-3x/day.
