- Email: [email protected]
Elbow flexion test in the normal population
The Journal of HAND SURGERY
Gliekman et al.
19. Heath ML. Deaths after intravenous regional anaesthesia. Br Med J 1982;285:913-4. 20. Grice SC, Morel1 RC, Balestrieri FJ, Stump DA, Howard G. Intravenous regional anesthesia: evaluation and prevention of leakage under the tourniquet. Anaesthesia 1986;65:316-20. recommended doses” 21. Scott DB . Editorial-“Maximum of local anaesthetic drugs. Br J Anaesth 1989;63:373-4.
22. Braid DP, Scott DB. The systemic absorption of local analgesic drugs. Br J Anaesth 1965;37:394-404. 23. Tucker GT, Mather LE. Properties, absorption and disposition of local anaesthetic agents. In: Cousins MJ, Bridenbaugh PO, eds. Neural Blockade. Philadelphia: JB Lippincott, 1988:62-3.
Elbow flexion test in the normal population The elbow flexion test was investigated in 204 elbows in 102 normal volunteers. The effects of various wrist and shoulder positions were also studied. In 20 elbows in 15 persons (10%) flexion tests were positive with the wrist and shoulder in neutral position. In 27 elbows in 20 persons (13%) tests were positive with wrist extension and shoulder abduction. (J HAND SURG 1992;17A:86-9.)
Ghazi M Rayan, MD, FACS, Christine Jensen, MS, OTR, and James Duke, PhD, Oklahoma City, Okla.
The elbow flexion
test is often used as a provocative test for diagnosing compression neuropathy of the ulnar nerve at the cubital tunnel. The test is conducted by fully flexing the elbow for 1 minute. Experiencing paresthesias in the distribution of the ulnar nerve constitutes a positive test. Wadsworth’ observed aggravation of symptoms in patients with cubital tunnel syndrome when full elbow flexion was maintained for 5 minutes. Dellon* used the elbow flexion test in a staging system for ulnar nerve compression at the elbow. The purpose of this study was to investigate the incidence of positive elbow flexion test in the normal population and the influence of various positions of the wrist and shoulder on the results.
Departmentof OrthopedicSurgery, and Baptist Medical Center, OklahomaCity, Okla
From the Hand Surgery Section, Received for publication April 15, 1991.
Jan.
15, 1991; accepted
in revised form
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to tbe subject of this article. Reprint requests: G. M. Rayan, homa City, OK 73 112.
MD, 3433 NW 56th. # 850, Okla-
3/l/30634
86
THE JOURNAL OF HAND SURGERY
Materials
and methods
Two hundred four ulnar nerves of 102 adult volunteers were used for this study. There were 40 men and 62 women. Ages ranged from 18 to 89 years. Ninetytwo (90%) of the volunteers were right-handed, nine (9%) were left-handed, and one was ambidextrous. Eight percent of these volunteers had demanding occupations that required heavy or repetitive use of the upper extremity. The remaining volunteers did not have physically demanding occupations. All volunteers were medical personnel or patients who were seen in the orthopedic clinic because of various musculoskeletal disorders other than of the upper extremity. They had no symptoms of ulnar nerve compression. Patients with a history of compression neuropathy, polyneuropathy, systemic disease, or fractures around the elbow were excluded from the study. The volunteers’ response to Tinel’s sign was assessed. The test was performed on both sides by gentle percussion with two fingers over the nerve in the cubital tunnel with the elbow in 90 degrees of flexion. A positive Tinel’s sign was confirmed by the presence of paresthesias in the sensory distribution of the ulnar nerve. Ulnar nerves were examined for instability within the cubital tunnel. The patient was asked to fully flex the elbow. The nerve was inspected and palpated
Vol. 17A. No. 1 January 1992
for instability, either subluxation (displacement to the tip of the medial epicondyle) or dislocation (displacement anterior to the medial epicondyle). The elbow flexion test was performed with the patient seated. The elbow was fully flexed passively with both the wrist and the shoulder in neutral position (i.e., with the arm at the side of the body). This was maintained for 1 minute. Paresthesias in the ulnar digits were graded, and the response was recorded as follows: 0 = no paresthesia; + = mild paresthesia; + + = moderate paresthesia; + + + = severe paresthesia. Four different tests (Tl to T4) were performed in each patient. First, the elbow flexion test was performed with the shoulder and wrist in neutral position (Tl). The same test was also performed with the wrist in full extension (T2). The test was then performed with the shoulder in 90 degrees of abduction (T3). Finally, the test was performed with the shoulder in 90 degrees of abduction and the wrist in full extension (T4). An age-related analysis of the elbow flexion test was carried out. The volunteers were divided into two age groups. In the first group, 45 years and older, degenerative joint disease is more common. In the second group, less than 45 years of age, there is a tendency to use the extremity more actively. Fisher’s exact probabilities and chi-square analysis3 were used to compare distribution of test results.
Results Eleven volunteers (11%) had at least one positive elbow flexion test response bilaterally. Twelve volunteers ( 12%) demonstrated positive flexion test responses only on the nondominant side. Fourteen volunteers (14%) demonstrated positive elbow flexion test responses only on the dominant side or bilaterally if ambidextrous. Forty-eight elbows in 37 volunteers (24%) had at least one positive flexion test response (i.e., Tl to T4). The majority of these had mild or moderate ( + , + +) paresthesias. Only 2 elbows (1 volunteer) had severe ( + + +) paresthesias. Twenty elbows in 15 volunteers (10%) had positive Tl test responses; five volunteers had bilaterally positive test responses. Fifteen elbows in 13 volunteers (7%) had positive T2 flexion test responses. The T3 flexion test was found to be positive in 23 elbows in 19 volunteers (11%). Twentyseven elbows in 22 volunteers (13%) had positive T4 flexion test responses; in five volunteers the tests were positive bilaterally. In elbows with positive T4 test responses (n = 27) 59% had positive T3 test responses and 30% had positive T2 or T 1 test responses. In elbows with positive T3 test responses (n = 23), 70% had positive T4 responses and 35% had positive Tl test responses. In elbows with positive Tl responses
Elbow ,jexion
test
87
Table I. Summary of positive flexion tests for persons (n = 102) and elbows (n = 204) Persons
Elbows
Test
N
%
N
%
Tinel’s sign Subluxation Flexion tests Tl T2 Tl or T2 T3 T4 T3 or T4 T4 with Tl T4 with T2 T4 with T3 Tl with T2 Tl with T3 TI with T4
32 14
31 14
48 I5
24
15 13 16 19 22 21 6 6 13
15 13 16 19 22 27 6 6 13 6
20 15 2-l 23 27 34 8
10
7
16 8
13 11 13 17 4
8 4 4
8
(n = 20) 40% had positive T4 and T3 flexion test responses (Table I). The distribution of Tl test results was significantly different from those of T2, T3, and T4 test results. The results of these alternative tests (T2, T3, and T4) were not significantly different. Seventy-seven volunteers were less than 45 years of age. Thirty-three elbows in 26 persons (21%) had positive elbow flexion test responses. Seven volunteers had at least one positive elbow flexion test response bilaterally. For volunteers at least 45 years of age (n = 25)) 15 elbows in 11 volunteers (30%) had positive elbow flexion test responses. Four of these volunteers had bilateral positive test responses. Forty-eight elbows in 32 volunteers (24%) demonstrated a positive Tinel’s sign (Table I). Of these volunteers, 16 (50%) had a positive Tinel’s sign bilaterally. Among volunteers who demonstrated a unilateral positive Tinel’s sign (n = 16), 9 expressed positive signs in their dominant side. Seventeen of the 32 volunteers with positive Tinel’s sign (53%) had at least one positive flexion test. Dislocation of the ulnar nerve with elbow flexion was not documented. Subluxation was present in 15 elbows (7%) in 14 volunteers. Among the 15 elbows, only three (20%) were associated with at least one positive elbow flexion test (Table I).
Discussion The ulnar nerve pierces the medial intermuscular septum in the arm and accompanies the ulnar collateral artery to the cubital tunnel. The cubital tunnel is a fibroosseous tunnel, which begins proximally at the
88
Rayan et al.
ulnar groove behind the medial epicondyle. It is bordered laterally by the elbow joint and the medial collateral ligament, anteriorly by the medial epicondyle, and posteromedially by the fibroaponeurotic triangular ligament. This arcuate ligament is located between the two heads of the flexor carpi ulnaris and forms the roof of the cubital tunnel. Following its course in the canal, the nerve passes between the two heads of the flexor carpi ulnaris and continues on the palmar surface of the flexor digitornm profundus. Under normal conditions the capacity of the cubital tunnel is maximal with elbow extension. Elbow flexion decreases the volume of the cubital tunnel because of tightness of the arcuate ligament and bulging of the medial elbow ligament. Vanderpool et a1.4 observed that elbow flexion will lead to stretching of the aponeurosis. The distance between the ulnar and humeral attachments of the aponeurosis increased by 5 mm for each 45 degrees of flexion. Apfelberg and Larson5 demonstrated a 55% narrowing of the cubital tunnel and postcondylar groove during elbow flexion. They described the cross-sectional anatomy of the condylar groove as rounded and spacious during extension and flattened, triangular, or ellipsoid during flexion. In vivo, this pressure phenomenon may be aggravated by flexor carpi ulnaris muscle contraction. MacnicoP investigated the extraneural pressure of the ulnar nerve at the elbow in fresh cadavers. The pressure was measured in various elbow and shoulder positions. During elbow flexion the ulnar nerve migrated proximally. Stretching and varying degrees of anterior subluxation of the ulnar nerve in the cubital tunnel were also observed. Elbow flexion produced a significant rise in pressure at the postcondylar groove and the cubital tunnel, with further increase on abduction of the shoulder. Checkles et a1.7 found that the position of the elbow influenced the conduction velocity of the ulnar nerve. Jones and Gauntt’ studied in fresh cadavers the influence of elbow position on ulnar nerve length at the cubital tunnel. The difference in nerve length between neutral and full flexion positions was 0.8 cm. Apfelberg and Larson5 documented 1 cm ulnar nerve excursion proximal to the elbow and 0.6 cm distal to the elbow. Wilgis and Murphy’ studied the longitudinal excursion of the ulnar nerve and found it to average 9.8 mm proximal and 3 mm distal to the elbow. We studied the clinical effects of elbow flexion in a normal population with different positions of the shoulder and wrist. We found that approximately 10% of the elbows studied had a positive response to the standard most commonly performed flexion test (Tl) (i.e., with the wrist and shoulder in neutral position). Also, our
The Journal of HAND SURGERY
finding of 48 elbows (24%) of a symptom-free population with positive elbow flexion test responses (using any of four tests) is high. The majority of these volunteers did not engage in demanding jobs that required repetitive or strenuous use of the upper extremity. When the test was performed with the wrist in extension and the shoulder in abduction (T4), approximately 13% of the elbows studied had positive responses. Shoulder abduction (T3 and T4) was associated with an increased number of positive test results. The extended position of the wrist made a difference only when the shoulder was abducted. These findings are consistent with those of previous studies that nerve pressure, compression, and elongation do increase in this upper extremity position. There was an increased tendency, without statistical significance, for persons above 45 years of age to have a higher incidence of positive elbow flexion. This perhaps is due to a greater incidence of degenerative joint disease of the elbow in this group. There was an increased tendency for the positive elbow flexion test result and Tinel’s sign to occur on the dominant side. A positive Tinel’s sign was observed in 24% of the elbows studied in 23 volunteers; 50% of these were bilateral. There was a tendency for volunteers with a positive Tinel’s sign to have a positive elbow flexion test response (53%). Fourteen percent had subluxation of the nerve with elbow flexion. This is in agreement with the findings by Childress lo of recurrent subluxation of the ulnar nerve in 16% of the population. This was not associated with an increase in positive flexion test results. In fact, there was less tendency for volunteers with nerve instability to have a positive elbow flexion test response as compared with the general population. This is perhaps due to decreased excursion, elongation, and tension while the nerve is anteriorly displaced. Traumatic attenuation of the ligament may lead to symptomatic recurrent dislocation of the nerve.” The possible congenital absence or attentuation of the arcuate ligament may cause less nerve compression. Compresion neuropathy of the ulnar nerve at the elbow may occur in the work place because of repetitive use of the upper extremity in maneuvers requiring shoulder abduction and elbow flexion. This leads to nerve compression as a result of increased pressure in the cubital tunnel and repeated friction as the nerve slides in the tunnel. Such a position is assumed during sleep and therefore explains the night paresthesias in the ulnar nerve distribution in patients with cubital tunnel syndrome and in the susceptible or borderline normal population. Our observations suggest that the elbow flexion test alone may have a limited value as a
Vol. 17A, No. 1 January 1992
provocative test for diagnosis of cubital tunnel syndrome. In a clinical setting, a positive elbow flexion test response, especially when there is mild paresthesia and lack of other clinical findings, should not be considered diagnostic of compression neuropathy. It is not clear whether a negative elbow flexion test rules out the diagnosis in persons with symptoms whose ulnar nerves do not sublux. Further research correlating nerve-conduction studies and elbow flexion tests in these patients may be helpful. Whether the pathophysiology of paresthesias encountered during a positive elbow flexion test response is vascular or mechanical in origin is not clear. Most likely the increased pressure within the canal leads to decreased intraneural blood flow with subsequent transient conduction block. Lundborg et al.‘* found, in an experimental study, that ischemia plays a major role in early stages of nerve compression, when symptoms are transient and rapidly reversible. It is also possible that mechanical deformation from the arcuate ligament may play a role. Perhaps volunteers with strongly positive elbow flexion test represent a group of persons who are susceptible to compression neuropathy of the ulnar nerve at the elbow. REFERENCES 1. Wadsworth T. The external compression syndrome of the ulnar nerve at the cubital tunnel. Clin Orthop 1977;124:189-204.
Elbow Jlexion test
89
2. Dellon AL. Review of treatment results for ulnar nerve entrapment at the elbow. J HAND SURG 1989;14A:688700. 3. Fleiss JL: Statistical methods for rates and proportions. New York: John Wiley, 1981. 4. Vanderpool DW, Chalmers J, Lamb DW, Whiston TB. Peripheral compression lesions of the ulnar nerve. J Bone Joint Surg 1968;50B:792-803. 5. Apfelberg DB , Larson SJ. Dynamic anatomy of the ulnar nerve at the elbow. Plast Reconstr Surg 1973;51:76-81. 6. Macnicol MF. Extraneural pressures affecting the ulnar nerve at the elbow. Hand 1982;14:5-11. 7. Checkles N, Russakov A, Piero DL. Ulnar nerve conduction velocity effect of elbow position on measurement. Arch Phys Med Rehabil 1971;52:362-5. 8. Jones R, Gauntt C. Medical epicondylectomy for ulnar nerve compression syndrome at the elbow. Clin Orthop 1979;139:174-8. 9. Wilgis EFS, Murphy R. The significance of longitudinal excursion in peripheral nerves. Hand Clinics 1986;2: 761-6. 10. Childress HM. Recurrent ulnar nerve dislocation at the elbow. Clin Orthop 1975;108:168. 11. Rayan GM. Recurrent anterior dislocation of the ulnar nerve at the cubital tunnel. Plast Reconstr Surg 1990;86:773-5. 12. Lundborg G, Gelberman R, Minteer-Convery M, et al. Median nerve compression in the carpal tunnelfunctional response to experimentally induced controlled pressure. J HAND SURG 1982;7:252-9.
Gliekman et al.
19. Heath ML. Deaths after intravenous regional anaesthesia. Br Med J 1982;285:913-4. 20. Grice SC, Morel1 RC, Balestrieri FJ, Stump DA, Howard G. Intravenous regional anesthesia: evaluation and prevention of leakage under the tourniquet. Anaesthesia 1986;65:316-20. recommended doses” 21. Scott DB . Editorial-“Maximum of local anaesthetic drugs. Br J Anaesth 1989;63:373-4.
22. Braid DP, Scott DB. The systemic absorption of local analgesic drugs. Br J Anaesth 1965;37:394-404. 23. Tucker GT, Mather LE. Properties, absorption and disposition of local anaesthetic agents. In: Cousins MJ, Bridenbaugh PO, eds. Neural Blockade. Philadelphia: JB Lippincott, 1988:62-3.
Elbow flexion test in the normal population The elbow flexion test was investigated in 204 elbows in 102 normal volunteers. The effects of various wrist and shoulder positions were also studied. In 20 elbows in 15 persons (10%) flexion tests were positive with the wrist and shoulder in neutral position. In 27 elbows in 20 persons (13%) tests were positive with wrist extension and shoulder abduction. (J HAND SURG 1992;17A:86-9.)
Ghazi M Rayan, MD, FACS, Christine Jensen, MS, OTR, and James Duke, PhD, Oklahoma City, Okla.
The elbow flexion
test is often used as a provocative test for diagnosing compression neuropathy of the ulnar nerve at the cubital tunnel. The test is conducted by fully flexing the elbow for 1 minute. Experiencing paresthesias in the distribution of the ulnar nerve constitutes a positive test. Wadsworth’ observed aggravation of symptoms in patients with cubital tunnel syndrome when full elbow flexion was maintained for 5 minutes. Dellon* used the elbow flexion test in a staging system for ulnar nerve compression at the elbow. The purpose of this study was to investigate the incidence of positive elbow flexion test in the normal population and the influence of various positions of the wrist and shoulder on the results.
Departmentof OrthopedicSurgery, and Baptist Medical Center, OklahomaCity, Okla
From the Hand Surgery Section, Received for publication April 15, 1991.
Jan.
15, 1991; accepted
in revised form
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to tbe subject of this article. Reprint requests: G. M. Rayan, homa City, OK 73 112.
MD, 3433 NW 56th. # 850, Okla-
3/l/30634
86
THE JOURNAL OF HAND SURGERY
Materials
and methods
Two hundred four ulnar nerves of 102 adult volunteers were used for this study. There were 40 men and 62 women. Ages ranged from 18 to 89 years. Ninetytwo (90%) of the volunteers were right-handed, nine (9%) were left-handed, and one was ambidextrous. Eight percent of these volunteers had demanding occupations that required heavy or repetitive use of the upper extremity. The remaining volunteers did not have physically demanding occupations. All volunteers were medical personnel or patients who were seen in the orthopedic clinic because of various musculoskeletal disorders other than of the upper extremity. They had no symptoms of ulnar nerve compression. Patients with a history of compression neuropathy, polyneuropathy, systemic disease, or fractures around the elbow were excluded from the study. The volunteers’ response to Tinel’s sign was assessed. The test was performed on both sides by gentle percussion with two fingers over the nerve in the cubital tunnel with the elbow in 90 degrees of flexion. A positive Tinel’s sign was confirmed by the presence of paresthesias in the sensory distribution of the ulnar nerve. Ulnar nerves were examined for instability within the cubital tunnel. The patient was asked to fully flex the elbow. The nerve was inspected and palpated
Vol. 17A. No. 1 January 1992
for instability, either subluxation (displacement to the tip of the medial epicondyle) or dislocation (displacement anterior to the medial epicondyle). The elbow flexion test was performed with the patient seated. The elbow was fully flexed passively with both the wrist and the shoulder in neutral position (i.e., with the arm at the side of the body). This was maintained for 1 minute. Paresthesias in the ulnar digits were graded, and the response was recorded as follows: 0 = no paresthesia; + = mild paresthesia; + + = moderate paresthesia; + + + = severe paresthesia. Four different tests (Tl to T4) were performed in each patient. First, the elbow flexion test was performed with the shoulder and wrist in neutral position (Tl). The same test was also performed with the wrist in full extension (T2). The test was then performed with the shoulder in 90 degrees of abduction (T3). Finally, the test was performed with the shoulder in 90 degrees of abduction and the wrist in full extension (T4). An age-related analysis of the elbow flexion test was carried out. The volunteers were divided into two age groups. In the first group, 45 years and older, degenerative joint disease is more common. In the second group, less than 45 years of age, there is a tendency to use the extremity more actively. Fisher’s exact probabilities and chi-square analysis3 were used to compare distribution of test results.
Results Eleven volunteers (11%) had at least one positive elbow flexion test response bilaterally. Twelve volunteers ( 12%) demonstrated positive flexion test responses only on the nondominant side. Fourteen volunteers (14%) demonstrated positive elbow flexion test responses only on the dominant side or bilaterally if ambidextrous. Forty-eight elbows in 37 volunteers (24%) had at least one positive flexion test response (i.e., Tl to T4). The majority of these had mild or moderate ( + , + +) paresthesias. Only 2 elbows (1 volunteer) had severe ( + + +) paresthesias. Twenty elbows in 15 volunteers (10%) had positive Tl test responses; five volunteers had bilaterally positive test responses. Fifteen elbows in 13 volunteers (7%) had positive T2 flexion test responses. The T3 flexion test was found to be positive in 23 elbows in 19 volunteers (11%). Twentyseven elbows in 22 volunteers (13%) had positive T4 flexion test responses; in five volunteers the tests were positive bilaterally. In elbows with positive T4 test responses (n = 27) 59% had positive T3 test responses and 30% had positive T2 or T 1 test responses. In elbows with positive T3 test responses (n = 23), 70% had positive T4 responses and 35% had positive Tl test responses. In elbows with positive Tl responses
Elbow ,jexion
test
87
Table I. Summary of positive flexion tests for persons (n = 102) and elbows (n = 204) Persons
Elbows
Test
N
%
N
%
Tinel’s sign Subluxation Flexion tests Tl T2 Tl or T2 T3 T4 T3 or T4 T4 with Tl T4 with T2 T4 with T3 Tl with T2 Tl with T3 TI with T4
32 14
31 14
48 I5
24
15 13 16 19 22 21 6 6 13
15 13 16 19 22 27 6 6 13 6
20 15 2-l 23 27 34 8
10
7
16 8
13 11 13 17 4
8 4 4
8
(n = 20) 40% had positive T4 and T3 flexion test responses (Table I). The distribution of Tl test results was significantly different from those of T2, T3, and T4 test results. The results of these alternative tests (T2, T3, and T4) were not significantly different. Seventy-seven volunteers were less than 45 years of age. Thirty-three elbows in 26 persons (21%) had positive elbow flexion test responses. Seven volunteers had at least one positive elbow flexion test response bilaterally. For volunteers at least 45 years of age (n = 25)) 15 elbows in 11 volunteers (30%) had positive elbow flexion test responses. Four of these volunteers had bilateral positive test responses. Forty-eight elbows in 32 volunteers (24%) demonstrated a positive Tinel’s sign (Table I). Of these volunteers, 16 (50%) had a positive Tinel’s sign bilaterally. Among volunteers who demonstrated a unilateral positive Tinel’s sign (n = 16), 9 expressed positive signs in their dominant side. Seventeen of the 32 volunteers with positive Tinel’s sign (53%) had at least one positive flexion test. Dislocation of the ulnar nerve with elbow flexion was not documented. Subluxation was present in 15 elbows (7%) in 14 volunteers. Among the 15 elbows, only three (20%) were associated with at least one positive elbow flexion test (Table I).
Discussion The ulnar nerve pierces the medial intermuscular septum in the arm and accompanies the ulnar collateral artery to the cubital tunnel. The cubital tunnel is a fibroosseous tunnel, which begins proximally at the
88
Rayan et al.
ulnar groove behind the medial epicondyle. It is bordered laterally by the elbow joint and the medial collateral ligament, anteriorly by the medial epicondyle, and posteromedially by the fibroaponeurotic triangular ligament. This arcuate ligament is located between the two heads of the flexor carpi ulnaris and forms the roof of the cubital tunnel. Following its course in the canal, the nerve passes between the two heads of the flexor carpi ulnaris and continues on the palmar surface of the flexor digitornm profundus. Under normal conditions the capacity of the cubital tunnel is maximal with elbow extension. Elbow flexion decreases the volume of the cubital tunnel because of tightness of the arcuate ligament and bulging of the medial elbow ligament. Vanderpool et a1.4 observed that elbow flexion will lead to stretching of the aponeurosis. The distance between the ulnar and humeral attachments of the aponeurosis increased by 5 mm for each 45 degrees of flexion. Apfelberg and Larson5 demonstrated a 55% narrowing of the cubital tunnel and postcondylar groove during elbow flexion. They described the cross-sectional anatomy of the condylar groove as rounded and spacious during extension and flattened, triangular, or ellipsoid during flexion. In vivo, this pressure phenomenon may be aggravated by flexor carpi ulnaris muscle contraction. MacnicoP investigated the extraneural pressure of the ulnar nerve at the elbow in fresh cadavers. The pressure was measured in various elbow and shoulder positions. During elbow flexion the ulnar nerve migrated proximally. Stretching and varying degrees of anterior subluxation of the ulnar nerve in the cubital tunnel were also observed. Elbow flexion produced a significant rise in pressure at the postcondylar groove and the cubital tunnel, with further increase on abduction of the shoulder. Checkles et a1.7 found that the position of the elbow influenced the conduction velocity of the ulnar nerve. Jones and Gauntt’ studied in fresh cadavers the influence of elbow position on ulnar nerve length at the cubital tunnel. The difference in nerve length between neutral and full flexion positions was 0.8 cm. Apfelberg and Larson5 documented 1 cm ulnar nerve excursion proximal to the elbow and 0.6 cm distal to the elbow. Wilgis and Murphy’ studied the longitudinal excursion of the ulnar nerve and found it to average 9.8 mm proximal and 3 mm distal to the elbow. We studied the clinical effects of elbow flexion in a normal population with different positions of the shoulder and wrist. We found that approximately 10% of the elbows studied had a positive response to the standard most commonly performed flexion test (Tl) (i.e., with the wrist and shoulder in neutral position). Also, our
The Journal of HAND SURGERY
finding of 48 elbows (24%) of a symptom-free population with positive elbow flexion test responses (using any of four tests) is high. The majority of these volunteers did not engage in demanding jobs that required repetitive or strenuous use of the upper extremity. When the test was performed with the wrist in extension and the shoulder in abduction (T4), approximately 13% of the elbows studied had positive responses. Shoulder abduction (T3 and T4) was associated with an increased number of positive test results. The extended position of the wrist made a difference only when the shoulder was abducted. These findings are consistent with those of previous studies that nerve pressure, compression, and elongation do increase in this upper extremity position. There was an increased tendency, without statistical significance, for persons above 45 years of age to have a higher incidence of positive elbow flexion. This perhaps is due to a greater incidence of degenerative joint disease of the elbow in this group. There was an increased tendency for the positive elbow flexion test result and Tinel’s sign to occur on the dominant side. A positive Tinel’s sign was observed in 24% of the elbows studied in 23 volunteers; 50% of these were bilateral. There was a tendency for volunteers with a positive Tinel’s sign to have a positive elbow flexion test response (53%). Fourteen percent had subluxation of the nerve with elbow flexion. This is in agreement with the findings by Childress lo of recurrent subluxation of the ulnar nerve in 16% of the population. This was not associated with an increase in positive flexion test results. In fact, there was less tendency for volunteers with nerve instability to have a positive elbow flexion test response as compared with the general population. This is perhaps due to decreased excursion, elongation, and tension while the nerve is anteriorly displaced. Traumatic attenuation of the ligament may lead to symptomatic recurrent dislocation of the nerve.” The possible congenital absence or attentuation of the arcuate ligament may cause less nerve compression. Compresion neuropathy of the ulnar nerve at the elbow may occur in the work place because of repetitive use of the upper extremity in maneuvers requiring shoulder abduction and elbow flexion. This leads to nerve compression as a result of increased pressure in the cubital tunnel and repeated friction as the nerve slides in the tunnel. Such a position is assumed during sleep and therefore explains the night paresthesias in the ulnar nerve distribution in patients with cubital tunnel syndrome and in the susceptible or borderline normal population. Our observations suggest that the elbow flexion test alone may have a limited value as a
Vol. 17A, No. 1 January 1992
provocative test for diagnosis of cubital tunnel syndrome. In a clinical setting, a positive elbow flexion test response, especially when there is mild paresthesia and lack of other clinical findings, should not be considered diagnostic of compression neuropathy. It is not clear whether a negative elbow flexion test rules out the diagnosis in persons with symptoms whose ulnar nerves do not sublux. Further research correlating nerve-conduction studies and elbow flexion tests in these patients may be helpful. Whether the pathophysiology of paresthesias encountered during a positive elbow flexion test response is vascular or mechanical in origin is not clear. Most likely the increased pressure within the canal leads to decreased intraneural blood flow with subsequent transient conduction block. Lundborg et al.‘* found, in an experimental study, that ischemia plays a major role in early stages of nerve compression, when symptoms are transient and rapidly reversible. It is also possible that mechanical deformation from the arcuate ligament may play a role. Perhaps volunteers with strongly positive elbow flexion test represent a group of persons who are susceptible to compression neuropathy of the ulnar nerve at the elbow. REFERENCES 1. Wadsworth T. The external compression syndrome of the ulnar nerve at the cubital tunnel. Clin Orthop 1977;124:189-204.
Elbow Jlexion test
89
2. Dellon AL. Review of treatment results for ulnar nerve entrapment at the elbow. J HAND SURG 1989;14A:688700. 3. Fleiss JL: Statistical methods for rates and proportions. New York: John Wiley, 1981. 4. Vanderpool DW, Chalmers J, Lamb DW, Whiston TB. Peripheral compression lesions of the ulnar nerve. J Bone Joint Surg 1968;50B:792-803. 5. Apfelberg DB , Larson SJ. Dynamic anatomy of the ulnar nerve at the elbow. Plast Reconstr Surg 1973;51:76-81. 6. Macnicol MF. Extraneural pressures affecting the ulnar nerve at the elbow. Hand 1982;14:5-11. 7. Checkles N, Russakov A, Piero DL. Ulnar nerve conduction velocity effect of elbow position on measurement. Arch Phys Med Rehabil 1971;52:362-5. 8. Jones R, Gauntt C. Medical epicondylectomy for ulnar nerve compression syndrome at the elbow. Clin Orthop 1979;139:174-8. 9. Wilgis EFS, Murphy R. The significance of longitudinal excursion in peripheral nerves. Hand Clinics 1986;2: 761-6. 10. Childress HM. Recurrent ulnar nerve dislocation at the elbow. Clin Orthop 1975;108:168. 11. Rayan GM. Recurrent anterior dislocation of the ulnar nerve at the cubital tunnel. Plast Reconstr Surg 1990;86:773-5. 12. Lundborg G, Gelberman R, Minteer-Convery M, et al. Median nerve compression in the carpal tunnelfunctional response to experimentally induced controlled pressure. J HAND SURG 1982;7:252-9.