Updated: 11/5/2022

Cubital Tunnel Syndrome

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  • Summary
    • Cubital Tunnel Syndrome is a compressive neuropathy of the ulnar nerve caused by anatomic compression in the medial elbow.
    • Diagnosis is made clinically with presence of sensory changes to the ring and little finger, intrinsic muscle weakness and a positive tinel's sign over the cubital tunnel.
    • Treatment may be nonoperative modalities such as bracing or surgical decompression depending on the severity and duration of symptoms, and success of nonoperative treatment.
  • Epidemiology
    • Incidence
      • common
        • ~30 per 100,000 person annually
          • second most common compression neuropathy of upper extremity
    • Demographics
      • males > females
        • females more likely to present at earlier age
      • incidence increases with age in both men and women
  • Etiology
    • Pathophysiology
      • Cubital tunnel syndrome results from compression and traction on the ulnar nerve
      • Sites of entrapment
        • most common
          • between the two heads of FCU/aponeurosis (most common site)
          • within arcade of Struthers (hiatus in medial intermuscular septum)
          • between Osborne's ligament and MCL
        • less common sites of compression include
          • medial head of triceps
          • medial intermuscular septum
          • medial epicondyle
          • fascial bands within FCU
          • anconeus epitrochlearis (anomalous muscle from the medial olecranon to the medial epicondyle)
          • aponeurosis of FDS proximal edge
        • external sources of compression
          • fractures and medial epicondyle nonunions
          • osteophytes
          • heterotopic ossification
          • tumors and ganglion cysts
          • post-traumatic
    • Associated conditions
      • cubitus varus or valgus deformities
      • medial epicondylitis
      • burns
      • elbow contracture release
  • Anatomy
    • Ulnar nerve
      • arises from the medial cord of the brachial plexus (C8-T1)
      • lies posteromedial to brachial artery in anterior compartment of upper arm
      • pierces IM septum at arcade of Struthers 8 cm proximal to the medial epicondyle
      • runs behind medial epicondyle within the cubital tunnel
      • enters forearm between 2 heads (humeral and ulnar heads) of FCU 
      • runs between FCU and FDP
      • passes superficial to the transverse carpal ligament at the wrist
    • Cubital tunnel
      • roof
        • formed by FCU fascia and Osborne's ligament (travels from the medial epicondyle to the olecranon)
      • floor
        • formed by posterior oblique and transverse bands of MCL and elbow joint capsule
      • walls
        • formed by medial epicondyle and olecranon
  • Classification
      • McGowan and Dellon
      • Type 1
      • Subjective sensory symptoms without objective loss of two-point sensibility or muscular atrophy
      • Type 2A
      • Sensory symptoms + weakness on pinch and grip without atrophy
      • Type 2B
      • Sensory symptoms + atrophy and intrinsic muscle strength ≤ 3
      • Type 3
      • Profound muscular atrophy and sensory disturbance
  • Presentation
    • Symptoms
      • paresthesias of small finger, ulnar half of ring finger, and ulnar dorsal hand
        • exacerbating activities include
          • cell phone use (excessive flexion)
          • occupational or athletic activities requiring repetitive elbow flexion and valgus stress
      • night symptoms
        • caused by sleeping with arm in flexion
    • Physical exam
      • inspection and palpation
        • interosseous and first web space atrophy
        • ring and small finger clawing
        • observe ulnar nerve subluxation over the medial epicondyle as the elbow moves through a flexion-extension arc
      • sensory
        • decreased sensation in ulnar 1-1/2 digits
      • motor
        • loss of the ulnar nerve results in paralysis of intrinsic muscles (adductor pollicis, deep head FPB, interossei, and lumbricals 3 and 4) which leads to
          • weakened grasp
            • from loss of MP joint flexion power
          • weak pinch
            • from loss of thumb adduction (as much as 70% of pinch strength is lost)
          • Froment sign
            • compensatory thumb IP flexion by FPL (AIN) during key pinch
              • compensates for the loss of metacarpal adduction by adductor pollicis (ulna n.)
                • adductor pollicis muscle normally acts as a MCP flexor, first metacarpal adductor, and IP extensor
          • Jeanne sign
            • compensatory thumb MCP hyperextension and thumb adduction by EPL (radial n.) with key pinch
              • compensates for loss of IP extension and thumb adduction by adductor pollicis (ulna n.)
          • Wartenberg sign
            • persistent small finger abduction and extension during attempted adduction secondary to weak 3rd palmar interosseous and small finger lumbrical
          • Masse sign
            • palmar arch flattening and loss of ulnar hand elevation secondary to weak opponens digiti quinti and decreased small finger MCP flexion
      • extrinsic weakness
        • Pollock's sign
          • inability to flex DIPJ of ring and small fingers (weak FDP)
      • provocative tests
        • Tinel sign positive over cubital tunnel
        • elbow flexion test
          • positive when flexion of the elbow for > 60 seconds reproduces symptoms
        • direct cubital tunnel compression exacerbates symptoms
  • Studies
    • EMG / NCS
      • helpful in establishing diagnosis and prognosis
      • threshold for diagnosis
        • conduction velocity <50 m/sec across elbow
        • low amplitudes of sensory nerve action potentials and compound muscle action potentials
  • Differential
    • Ulnar Tunnel Syndrome
      • key findings that differentiate cubital tunnel syndrome from ulnar tunnel syndrome
        • found with cubital tunnel syndrome
          • less clawing
          • sensory deficit to dorsum of the hand
          • motor deficit to ulnar-innervated extrinsic muscles
          • Tinel sign at the elbow
          • positive elbow flexion test
    • C8 radiculopathy 
      • key finding that differentiate cubital tunnel syndrome from a C8 radiculpathy
        • cubital tunnel syndrome
          • weakness to distal phalanx flexion of middle and index finger (difficulty with fine motor function)
          • paresthesias in ring and little finger
        • C8 radiculopathy
          • symptoms improve with should abduction
  • Treatment
    • Nonoperative
      • NSAIDs, activity modification, and nighttime elbow extension splinting
        • indications
          • first line of treatment with mild symptoms
        • outcomes
          • management is effective in ~50% of cases
    • Operative
      • in situ ulnar nerve decompression without transposition
        • indications
          • when nonoperative management fails
          • before motor denervation occurs
        • outcomes
          • meta-analyses have shown similar clinical results with significantly fewer complications compared to decompression with transposition
          • 80-90% good results when symptoms are intermittent and denervation has not yet occurred
          • poor prognosis correlates most with intrinsic muscle atrophy
      • ulnar nerve decompression and anterior transposition
        • indications
          • failed in situ release
          • throwing athlete
          • patient with poor ulnar nerve bed from tumor, osteophyte, or heterotopic bone
        • outcomes
          • similar outcomes to in situ release but increased risk of creating a new point of compression
          • Improved outcomes with unstable nerves in the pediatric population
      • medial epicondylectomy
        • indications
          • visible and symptomatic subluxating ulnar nerve
          • thin patients with inadequate subcutaneous tissue to perform a transposition
        • outcomes
          • risk of destabilizing the medial elbow by damaging the medial ulnar collateral ligament
  • Techniques
    • NSAIDs, activity modification, and nighttime elbow extension splinting
      • technique
        • night bracing in 45° extension with forearm in neutral rotation
    • In situ ulnar nerve decompression
      • releasing the fascial structures superficial to the ulnar nerve along the medial aspect of the elbow
      • 4-cm incision midway between the olecranon and medial epicondyle
      • distally release Osborne ligament and the superficial and deep fascia of FCU
      • proximally release the fascia between the medial triceps and medial intermuscular septum
      • avoid circumferential dissection of the nerve to minimize devascularization and to avoid creating hypermobility of the nerve
      • endoscopically-assisted cubital tunnel release is an option
        • favorable early results but lacks long-term data
    • Decompression and transposition (submuscular, intramuscular, or subcutaneous)
      • decompress the nerve and circumferentially dissect the nerve to allow for transposition
      • excise the medial intermuscular septum
      • anteriorly transpose the nerve
        • secured with subcutaneous tissue,
        • placed anterior to a fascial sling,
        • or placed within or beneath the flexor pronator mass
    • Medial Epicondylectomy
      • decompress the nerve and then perform an oblique osteotomy of the medial epicondyle
      • preserve the insertion of the MCL + repair the periosteum
  • Complications
    • Recurrence
      • secondary to inadequate decompression, perineural scarring, or tethering at the intermuscular septum or FCU fascia
      • higher rate of recurrence than after carpal tunnel release
    • Neuroma formation
      • iatrogenic injury to a branch of the medial antebrachial cutaneous nerve may cause persistent posteromedial elbow pain 
        • crosses field 3cm distal to medial epicondyle 
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Questions (14)
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(OBQ18.37) A 51-year-old man complains of elbow pain and numbness into the hand. He is an electrician and enjoys playing outfield in his competitive softball league, and was a minor league baseball pitcher. He has a multiyear history of numbness and tingling into his ring and small fingers. On physical exam, he has decreased 2-point discrimination in his small finger and a positive Jeanne's sign. His active elbow range of motion is 0-120 degrees with full pronosupination, but flexion elicits a snapping sensation over his medial elbow. His radiographs are shown in figure A. What is the best treatment for this problem?

QID: 212933

Arthroscopic elbow debridement



In situ cubital tunnel decompression



Medial ulnar collateral ligament reconstruction



Cubital tunnel decompression with anterior transposition



Counter-force bracing



L 2 A

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(OBQ18.59) A 55-year-old patient presents with numbness and pain in the right ring and small fingers. He reports that his symptoms are worse at night. On examination, he has decreased sensation on the dorsal ulnar distribution of the hand with a positive Tinel sign at the medial elbow. There is no palpable subluxation at the medial elbow with flexion and extension. Electrodiagnostic studies from 3 months ago demonstrated decreased nerve conduction velocities in the ulnar nerve. Figures A and B demonstrate the radiographs of the right elbow. Symptoms continue to worsen despite nighttime extension splinting and NSAIDs. What is the best next step in treatment and the most likely site of compression for the patient?

QID: 212955

Repeat EMG; herniated nucleus pulposus



In situ cubital tunnel release; flexor carpi ulnaris aponeurosis



Medial epicondyle ostectomy; osteophyte



Anterior submuscular transposition; anconeus epitrochlearis



Anterior subcutaneous transposition; ligament of struthers



L 2 A

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(OBQ11.128) The physical exam finding demonstrated on the patient's right hand in the video (Figure V) is found with neuropathy of which of the following nerves?

QID: 3551

Musculocutaneous nerve



Anterior Interosseious Nerve (AIN



Radial nerve



Ulnar nerve



Median nerve



L 1 C

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(OBQ09.24) A 50-year-old man complains of numbness and tingling along his right small finger. Elbow flexion reproduces the numbness and tingling. Physical therapy and splinting have failed to relieve the symptoms. Which of the following is the most appropriate surgical intervention to alleviate the symptoms while minimizing complications?

QID: 2837

Simple ulnar nerve decompression at the cubital tunnel



Ulnar nerve decompression at the cubital tunnel with anterior submuscular transposition



Ulnar nerve decompression at the cubital tunnel with anterior subcutaneous transposition



Open carpal tunnel release



Endoscopic carpal tunnel release



L 2 C

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(OBQ09.1) All of the following are possible sites of compression for the ulnar nerve EXCEPT:

QID: 2814

arcade of Struthers



ligament of Struthers



flexor carpi ulnaris fascia



medial intermuscular septum



Osborne's ligament



L 2 C

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(SBQ05UE.66) A 20-year-old college football quarterback reports a 5-month history of gradually increasing medial elbow pain that occurs with throwing. The pain occasionally refers distally along the ulnar aspect of the forearm. He denies any weakness; however, he notes occasional paresthesias on the volar and dorsal aspect of his small finger. A nerve conduction velocity study demonstrates only slightly increased latency across the cubital tunnel. What structure may be contributing to his symptoms?

QID: 1851

Supracondylar process



Ulnar artery



Lacertus fibrosis



Arcade of Frohse



Anconeus epitrochlearis



L 1 D

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Evidence (23)
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