Clinical outcomes of ulnar nerve gliding exercise in the nonoperative treatment of cubital tunnel syndrome

Abstract

Background

In cubital tunnel syndrome, inflammation and edema around the ulnar nerve inhibit physiologic nerve gliding, causing pain, paresthesia, and muscle weakness. The objective of this study was to investigate the clinical outcomes of our developed ulnar nerve gliding exercise for cubital tunnel syndrome.

Methods

Seventeen patients with cubital tunnel syndrome underwent ulnar nerve gliding exercise. All patients had numbness and paresthesia of the ulnar aspect of the forearm and hand and tenderness over the cubital tunnel. Before treatment, 15 patients had McGowan grade 2 (moderate) abnormality, and 2 patients had grade 3 (severe). For our nonsurgical ulnar nerve release, an occupational therapist applied repetitive passive wrist movement at maximal elbow flexion position to improve ulnar nerve gliding twice weekly for 20 minutes each session (average treatment period: 5.8 months). Data regarding the visual analog scale of paresthesia, rate of positive elbow flexion tests, Semmes–Weinstein monofilament test, grip strength, pulp pinch strength, and motor and sensory nerve conduction velocities (6 accepted patients) before ulnar nerve gliding exercise were compared with the values at the final follow-up (average follow-up period: 64 months).

Results

Ulnar nerve gliding exercise significantly decreased the severity of paresthesia overall (P < .0001). In addition, the elbow flexion test (P = .0002) and Semmes–Weinstein monofilament test (P < .0001) improved and grip strength (P < .0001) and pulp pinch strength (P < .0001) increased comparable to those on the contralateral side. Motor and sensory nerve conduction velocities after ulnar nerve gliding exercise improved in 5 of 6 patients (83%) and 4 of 6 patients (67%), respectively. One patient with McGowan grade 3 abnormality failed ulnar nerve gliding exercise and underwent anterior subcutaneous transposition of the ulnar nerve.

Conclusion

The ulnar nerve gliding exercise by using repetitive passive wrist movement at the maximal elbow flexion can be a useful option for moderate cubital tunnel syndrome.

Ulnar nerve entrapment at the elbow—that is, cubital tunnel syndrome—is the most common ulnar nerve neuropathy.^2,6 The symptoms consist primarily of paresthesia and numbness in the ring and little fingers, decreased grip strength, and vague discomfort in the medial elbow; repetitive flexion of the elbow or external pressure at the ulnar aspect of the elbow can increase these abnormalities.¹⁰ Although surgical intervention is indicated when nonoperative treatment fails to provide adequate relief of symptoms,^2,5 nonoperative treatment is primarily recommended for cubital tunnel syndrome and includes night splinting, nonsteroidal anti-inflammatory medication, and physical or occupational therapy.^10,17

In cubital tunnel syndrome, inflammation and edema around the ulnar nerve inhibit physiologic nerve gliding, causing pain, paresthesia, and muscle weakness.⁹ Therefore, physical therapy focuses on improvement of ulnar nerve gliding to decrease peripheral nerve pressure,¹² resulting in recovery of blood circulation and axonal transport.¹¹ Recently, we developed a nonsurgical ulnar nerve release technique (ulnar nerve gliding exercise), which comprises repetitive passive wrist movement at the maximal elbow flexion, to treat cubital tunnel syndrome. Repetitive passive wrist movement promotes ulnar nerve gliding.⁷ The objective of this study was to investigate the clinical outcomes of our ulnar nerve gliding exercise for cubital tunnel syndrome. Our hypothesis was that our ulnar nerve gliding exercise might improve ulnar nerve symptom and increase nerve conduction velocity in cubital tunnel syndrome.

Materials and Methods

We retrospectively reviewed our database. From June 2007 through January 2015, 17 consecutive patients (11 men and 6 women; age: average, 61.4 years; range, 23-84 years) with cubital tunnel syndrome underwent ulnar nerve gliding exercise conducted by a single occupational therapist. The mean duration of symptoms before treatment was 17 months (range, 1-72 months). The severity of cubital tunnel syndrome was evaluated according to the McGowan grading system.¹³ According to this system, grade 1 (mild) is characterized by intermittent paresthesia and minor hypothesia without muscle weakness. Grade 2 (moderate) is defined as persistent paresthesia, hypothesia, and mild weakness of ulnar innervated muscles. Patients with grade 3 (severe) cubital tunnel syndrome have persistent paresthesia, marked loss of sensation, muscle atrophy, and digital clawing. Accordingly, before treatment, 15 of our 17 patients had McGowan grade 2 abnormality, and the remaining 2 patients had McGowan grade 3. Patients with past or present symptoms associated with the cervical spine, clinical signs of another nerve problem, or trauma or surgery to the same arm were not included. In addition, 7 of our patients had nonpainful and functional mild osteoarthritis in the elbow joint. Before visiting our clinic, all patients had taken nonsteroidal anti-inflammatory medication, which had not alleviated their symptoms; night splinting was not used in this series. The mean duration of nerve gliding exercise was 5.8 months (range, 2-15 months); average follow-up was 64 months (range, 30-121 months). All patients signed an informed consent form approved by the Institutional Review Board at our university (Osaka Medical College, No. 1855).

Nonsurgical ulnar nerve release

Our ulnar nerve gliding exercise is aimed at reducing intraneural and extraneural edema, increasing blood circulation, and restoring neural tissue mobility by improving ulnar nerve gliding around the cubital tunnel.⁶ In our technique, the maximal elbow flexion angle that could be achieved without inducing any cubital tunnel symptoms was defined as the appropriate elbow flexion (ulnar nerve tensioning) for nonsurgical ulnar nerve release (Fig. 1). The average elbow flexion was 88.5° (range, 70°-120°) in this study. With the patient in lying supine, an occupational therapist applied repetitive passive wrist motion to improve ulnar nerve gliding twice weekly for 20 min each session (Fig. 1). Patients did not apply the other nonoperative treatment including self-exercises, night splinting, and medication during our ulnar nerve gliding exercise.

Figure 1.

Ulnar nerve gliding exercise. The occupational therapist applied repetitive passive wrist movement in flexion–extension (red arrows) at the maximum elbow flexion to improve ulnar nerve gliding.

Patient assessment

The severity of paresthesia in the forearm and hand was evaluated by using a visual analog scale (VAS) consisting of a 10-cm horizontal line, where 0 represented no paresthesia and 10 maximal paresthesia.^6,15,17 The Semmes–Weinstein monofilament test (SW test) was performed by applying force-calibrated monofilaments to assess tactile sensitivity of the hands.¹⁵ The monofilament was applied perpendicularly to the digital surface, and the pressure was increased until the monofilament began to bend. A positive response was recorded when the subject identified which digit was pressed with the monofilament. Each region was tested beginning with the smallest monofilament (No. 2.83 force, 0.07 g) and progressed to successively larger monofilament (No. 6.65 force, 300 g). Grip strength was measured by using a handheld dynamometer, and pulp pinch strength was measured by using a standard dynamometer between the tips of the thumb and smallest finger. The elbow flexion test⁴ was performed in the sitting position. Both elbows were fully flexed, with full extension of the wrist to maximize tensile forces on the ulnar nerve; when pain, numbness, or tingling occurred or increased within 3 minutes, the elbow flexion test was judged as positive.

In addition, 6 patients, who accepted both before our ulnar nerve gliding exercise and at the final treatment, underwent ulnar nerve conduction studies. For motor nerve conduction studies, the ulnar nerve was stimulated below and above the elbow. The stimulating electrode below the elbow was located 4 cm distal to the center of the line connecting the olecranon and medial epicondyle, in the direction of the ulnar styloid process. The stimulating electrode above the elbow was placed 6 cm proximal to the line connecting the olecranon and medial epicondyle. Recording electrodes were placed above the abductor digiti minimi muscle. Sensory nerve conduction was measured antidromically.

Statistical analysis

Using paired t-tests, we compared the VAS score of paresthesia, number of monofilaments in the SW test, grip strength, pulp pinch strength, and motor and sensory nerve conduction velocities before ulnar nerve gliding exercise with the values at final treatment. In addition, the rate of positive elbow flexion test before ulnar nerve gliding exercise was compared with that at the final treatment by using a Chi-square test. A significant difference was defined as P < .05.

To determine the appropriate sample size, a power analysis was performed by using the G∗Power3 statistical analysis software package. Power (1 − β) was calculated by defining the sample size as 17, the level of significance (α) as 0.05, and the effect size (ω) as 3.49 in the VAS score of paresthesia and 1.97 in the rate of positive elbow flexion test. The power analysis indicated that a total sample size of 17 patients provided 80% power (1 − β = 0.8; α = 0.05) to detect significant differences in VAS score of paresthesia and rate of positive elbow flexion test, assuming a power of 1.00.

Results

Subjective symptoms

Overall, severity of paresthesia in the forearm and hand due to cubital tunnel syndrome decreased significantly after ulnar nerve gliding exercise (VAS: before treatment, 6.7 ± 2.0 and at the final treatment, 0.5 ± 1.4; P < .0001) (Table I). In addition, treatment with ulnar nerve gliding exercise abolished symptoms of cubital tunnel syndrome in 16 of our 17 patients after an average of 5.8 months (range, 2-15 months). At the final follow-up (average, 65 months), 13 of these 16 patients had still no symptoms, and the other 3 patients had only mild symptoms that did not require any additional treatment. In 1 patient, who had undergone artificial dialysis for 12 years for chronic renal failure, 5 months of ulnar nerve gliding exercise had little effect (VAS: before treatment, 8.2 and at the final treatment, 5.9) on symptoms associated with McGowan grade 3 cubital tunnel syndrome; he therefore underwent anterior subcutaneous transposition of the ulnar nerve.

Table I.

Subjective symptom and physical findings before and after nonsurgical ulnar nerve release.^∗

	Before treatment	Final assessment	Contralateral side	P value	P value
				(Before treatment vs. final assessment)	(Final assessment vs. contralateral side)
Severity of paresthesia	6.7 (2.6-10)	0.5 (0-5.9)	0	<.001	.15
Semmes–Weinstein (No. of filament)	3.9 (2.83-6.65)	2.9 (2.83-3.61)	2.9 (2.83-3.61)	.0001	.33
Semmes–Weinstein (g)	18.4 (0.07-300)	0.1 (0.07-0.4)	0.1 (0.07-0.4)
Grip strength (kg)	20.7 (5-43)	28.3 (12-46)	25.9 (3.5-45)	<.0001	.14
Pulp pinch strength (kg)	0.7 (0-3.1)	1.7 (0.5-3.7)	1.7 (0-3.2)	.0006	.66
Positive rate of elbow flexion test	88%	24%	0%	.0002	.03

^∗Data are expressed as means (ranges).

Physical findings

Ulnar nerve gliding exercise significantly decreased the rate of positive elbow flexion tests (before treatment, 88% and at the final treatment, 24%; P = .0002) (Table I). In the SW test, the average number of monofilament until sensation was 3.9 (range, 2.83-6.65) before treatment and 2.9 (range, 2.83-3.61) at the final treatment (Table I), representing a significant improvement (P = .0001). Grip strength (before treatment, 20.7 ± 10.9 kg) and pulp pinch strength (0.7 ± 0.9 kg) increased significantly increased after ulnar nerve gliding exercise (at the final treatment, 28.3 ± 10.3 kg, P < .0001, and 1.7 ± 0.8 kg, P = .0006, respectively) (Table I). In addition, results of the SW test (P = .33), grip strength (P = .14), and pulp pinch strength (P = .66) did not differ between the affected side and contralateral side at the final treatment (Table I).

Ulnar nerve conduction velocity

In the 6 patients evaluated (which included the 1 who ultimately underwent anterior subcutaneous transposition of the ulnar nerve), motor and sensory nerve conduction velocities improved after ulnar nerve gliding exercise in 5 patients (83%) and 5 patients (67%), respectively. In the patient treated surgically, neither motor nor sensory nerve conduction velocity changed after ulnar nerve gliding exercise. Overall, motor nerve conduction velocity increased after ulnar nerve gliding exercise (before treatment, 36.9 m/s; at final treatment, 41.9 m/s; P = .04) (Table II).

Table II.

Ulnar nerve conduction velocity before and after nonsurgical ulnar nerve release.^∗

	Before treatment	Final assessment	P value
			(Before treatment vs. Final assessment)
Motor nerve velocity (m/s)	36.9 (15.5-48.4)	41.9 (23.2-50.8)	.04
Sensory nerve velocity (m/s)	16.2 (0-49.3)	29.4 (0-53.7)	.14

^∗Data are expressed as means (ranges).

Discussion

In patients with cubital tunnel syndrome, inflammation and edema around the ulnar nerve inhibit physiologic nerve gliding, resulting in pain, paresthesia, and muscle weakness.⁹ Current study showed that our developed ulnar nerve gliding exercise decreased paresthesia and increased grip strength and pulp pinch strength in 16 (94%) of 17 patients with cubital tunnel syndrome. In addition, the average number of monofilaments in the SW test, average grip strength, and pulp pinch strength improved to be equivalent to values for the contralateral side. Therefore, ulnar nerve gliding exercise of repetitive passive wrist movement at maximal elbow flexion can be an effective treatment option for cubital tunnel syndrome.

Nonoperative treatment is thought to be efficient for mild cubital tunnel syndrome.⁸ However, the current study showed that the ulnar nerve gliding exercise decreased paresthesia and increased grip strength and pulp pinch strength in all 15 patients with cubital tunnel syndrome of McGowan grade 2. Furthermore, motor nerve conduction velocity increased after ulnar nerve gliding exercise even in McGowan grade 2 or 3. Therefore, our ulnar nerve gliding exercise can be applied for moderate as well as mild cubital tunnel syndrome.

In our ulnar nerve gliding exercise, repetitive passive wrist movement at maximal elbow flexion induces nerve mobilization. However, aggressive mobilization of severely entrapped neuropathy may cause nerve elongation and thus exacerbate symptoms. Excessive nerve elongation produces electrophysiologic impairment^1,8,16 and reduces or abolishes epineural blood flow.^3,14,18 In our current series, one patient with severe cubital tunnel syndrome underwent anterior subcutaneous transposition of the ulnar nerve because nerve gliding exercise did not relieve his severe symptoms. Operative findings revealed that passive wrist movement failed to glide the ulnar nerve owing to its severe entrapment by bony deformity and synovitis. Therefore, our ulnar nerve gliding exercise is recommended for mild or moderate cubital tunnel syndrome, and surgical treatment is recommended for severe cubital tunnel syndrome with bony deformity.

The current study had a couple of limitations. First, this was a retrospective study. Second, the number of patients was relatively small, especially in motor and sensory nerve conduction velocities. Third, functional scores were not evaluated. Even though this study had the limitations, we believe that current clinical results are useful to treat cubital tunnel syndrome because clinical study of nerve gliding exercise was not reported before. We will assess nerve gliding and vascularity using ultrasound in the future study.

Conclusion

The ulnar nerve gliding exercise by using repetitive passive wrist movement at the maximal elbow flexion significantly improved ulnar nerve symptoms. The ulnar nerve gliding exercise can be a useful option for moderate cubital tunnel syndrome.

Disclaimers

Funding: No funding was disclosed by the authors.

Conflicts of interest: The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.