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Influence of knee positions and gender on the Ober test for length of the iliotibial band
Clinical Biomechanics 18 (2003) 77–79 www.elsevier.com/locate/clinbiomech
Brief report
Influence of knee positions and gender on the Ober test for length of the iliotibial band Richard L Gajdosik *, Matthew M Sandler, Heather L Marr Clinical Kinesiology Laboratory, Physical Therapy Department, School of Pharmacy and Allied Health Sciences, The University of Montana, Missoula, MT 59812-4680, USA Received 22 May 2002; accepted 22 October 2002
Abstract Objective. Examine the influence of knee positions and gender on the Ober test for the length of the iliotibial band. Design. A cross-sectional comparative repeated measures design. Background. The Ober test is in widespread use, yet the influence of knee positions and gender on the test has not been reported. Such information is needed to help clarify test results. Methods. The Ober test was administered with the knee flexed to 90° and extended to 0° to the right lower limb of 26 women and 23 men. The limb was lowered from abduction and the end point of hip abduction (positive angle) or hip adduction (negative angle) was measured in relation to neutral. Results. The hip adduction movement was restricted more with the knee flexed than with the knee extended for both genders ðP < 0:009Þ. With the knee flexed the mean hip abduction angle was less for men ðþ4°Þ than for women ðþ6°Þ ðP < 0:001Þ, and with the knee extended the mean hip adduction angle was greater for men ð9°Þ than for women ð4°Þ ðP < 0:001Þ. Conclusion. The Ober test with the knee flexed limited hip adduction more than with the knee extended for both men and women, and women had greater limitations than men. Relevance The Ober test with the knee flexed and with the knee extended yielded different results and may be considered different tests. Normal Ober test values for the two knee positions should be defined separately for men and women in order to understand how deviations from normal are related to pathologies. Ó 2002 Elsevier Science Ltd. All rights reserved. Keywords: Ober test; Iliotibial band length; Hip range of motion
1. Introduction The Ober test, first described by Ober (1936), is a common and widely accepted test for measuring the length of the iliotibial band (ITB). The ITB, also known as the iliotibial tract, is a lateral thickening of the fascia lata of the thigh that has primary attachments to the ilium superiorly, and to the lateral tuberosity of the tibia, the head of the fibula, the lateral condyle of the zfemur and lateral patellar retinaculum inferiorly. The ITB also is continuous with the lateral intermuscular septum of the thigh that is anchored to the shaft of
*
Corresponding author. E-mail address: [email protected] (R. L Gajdosik).
the femur. The gluteus maximus and tensor fascia lata muscles insert into the ITB, which can be considered the tendon of these muscles. The Ober test is administered to the lower limb (upper) with the patient side lying. The examiner stands behind the patient and moves the thigh of the tested limb into flexion, abduction, and extension. While stabilizing the pelvis with one hand, the examiner then lowers the limb into adduction until it stops, or until the pelvis starts to tilt downward, or both. The length of the ITB is then represented by the hip abduction or adduction angle in relation to a neutral position (0°) (Kendall et al., 1993). Although Ober first described the test with the knee flexed, our search of the literature found no accepted standard knee position for the test and no published studies that objectively reported the influence of knee
0268-0033/03/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 8 - 0 0 3 3 ( 0 2 ) 0 0 1 6 8 - 7
78
R. L Gajdosik et al. / Clinical Biomechanics 18 (2003) 77–79
flexion or knee extension on the testÕs results. Kendall et al. (1993) suggested that a normal ITB length would allow the thigh to drop slightly below horizontal (0°) with the knee flexed to 90°, and to about 10° below horizontal with the knee extended, but no objective data are available to support these guidelines. Moreover, gender differences have not been described. Most authorities have suggested that the knee should be flexed for the test as originally described by Ober (Kendall et al., 1993; Hoppenfield, 1976; Starkey and Ryan, 1996; Magee, 1997), but some have suggested that the test can also be modified by placing the knee in extension (Kendall et al., 1993; Magee, 1997; Hertling and Kessler, 1996). Although Kendall et al. (1993) indicated that hip adduction movement would be more limited with the knee flexed, others have suggested that the ITB has a greater stretch placed on it with the knee extended (Magee, 1997; Hertling and Kessler, 1996). If greater stretch is placed on the ITB with the knee extended, one would expect that this knee position would limit hip adduction movement more than with the knee flexed. Because of these conflicting opinions, and the lack of objective evidence to support published claims, we designed this study to examine the influence of two knee positions and gender on the hip abduction or adduction angle for the Ober test. The purposes of the study, therefore, were to examine the effects of knee flexion and knee extension on the Ober test and to compare independent samples of men and women.
2. Methods 2.1. Subjects Twenty-six non-disabled women (ages 20–43 years; mean 26, SD 5) and 23 non-disabled men (ages 23–37 years; mean 28, SD 4) participated with informed consent. The subjects had no history of hip or knee conditions that would confound the results and they all had passive knee flexion to at least 100°. The study was approved by The Institutional Review Board for the Use of Human Subjects in Research of The University of Montana. 2.2. Procedures A universal goniometer was used to measure hip abduction or adduction. Preliminary pilot work was completed to standardize the subject positioning, goniometer placement and instruction commands. One examiner (MMS) administered the test to the right limb with the knee held in either 0° of extension or in 90° of flexion, which were randomly ordered by a coin toss. Another examiner (HLM) positioned the goniometer,
and read and recorded the angle of hip abduction or adduction. Each knee position was tested 3 times within one test session. The reliability among the three trials (I C C , Model 2) for the women was 0.92 for knee extension and 0.87 for knee flexion. The I C C values for the men among the 3 trials were 0.82 for knee extension and 0.83 for knee flexion. The mean of the three trials was used for analysis. To prepare the subjects, a line was drawn on the midline anterior aspect of the right thigh between the anterior superior iliac spine and the patella. This line represented the longitudinal axis of the thigh and helped to ensure accurate alignment of the movable arm of the goniometer. Subjects were then positioned in left side lying on a treatment table with their shoulders and hips aligned perpendicular to the table. The left hip and knee were flexed to about 45° each, which helped to stabilize the pelvis and to prevent anterior tilting of the pelvis. The examiner stood behind the subject and stabilized the right side of the pelvis by pushing in a superior and downward direction with his left hand. With the right hand he grasped the subjectÕs right knee on its medial side and cradled the leg on his forearm with the knee either flexed or extended. The subjectÕs limb was then moved into hip flexion, abduction and extension, and then lowered into hip adduction. No medial rotation or flexion of the hip was allowed. The knee positions and neutral hip extension without hyperextension were confirmed with a goniometer by the second examiner before the limb was lowered. The end position of the thigh adduction movement was defined by the start of lateral tilting of the pelvis, or when movement stopped, or both. At this end position the second examiner aligned the stationary arm of the goniometer with both anterior superior iliac spines, aligned the moveable arm with the line drawn on the thigh, and then measured the angle of hip abduction or adduction. A neutral thigh position was defined as 0°. Abduction degrees were defined as positive and adduction degrees were defined as negative in relation to this neutral position. 2.3. Data analysis and results Descriptive statistics were tabulated for the hip abduction and adduction angles (Table 1). A two-way A N O V A for repeated measures showed that the angles were significantly less with the knee flexed than with the knee extended for both women and men combined ðP ¼ 0:009Þ. The men had greater adduction than the women for both knee positions ðP < 0:001Þ, and there was a significant interaction ðP ¼ 0:04Þ. Separate oneway A N O V A s indicated that knee flexion limited the hip adduction movement more than knee extension for both the women ðP < 0:001Þ and the men ðP < 0:001Þ (see Table 1).
R. L Gajdosik et al. / Clinical Biomechanics 18 (2003) 77–79 Table 1 Descriptive statistics for the results of the Ober test with the knee held at 0° of extension and 90° of flexion for the women ðn ¼ 26Þ and the men ðn ¼ 23Þ Mean
SD
Range
Women Knee extension (°) Knee flexion (°)
)4 þ6
þ5 þ5
)11 to þ5 )3 to þ16
Men Knee extension (°) Knee flexion (°)
)9 þ4
þ6 þ5
)20 to þ3 )4 to þ15
Positive numbers indicate hip abduction and negative numbers indicate hip adduction in relation to the neutral position of 0°.
2.4. Discussion The results indicated that knee flexion to 90° limited hip adduction movement more than with the knee held in 0° of extension, which is in agreement with the results suggested by Kendall et al. (1993). Because the ITB attaches into the lateral patellar reticulum, knee flexion probably lengthened the ITB, as well as the tensor fascia latae muscle by way of this attachment, and this contributed to the limited hip adduction movement. The ITB is continuous with the fascia lata of the anterior lateral aspect of the thigh, so stretching this aspect of the fascia lata with knee flexion also may have contributed to the limited hip adduction movement in addition to stretching the ITB alone. Greater tightness of the fascia lata over the anterior-lateral aspect of the thigh was obvious with palpation when the knee was flexed compared to when the knee was extended. Based on the objective goniometric results and our observations, it appeared that this part of the fascia latae, and perhaps other structures (i.e., vastus lateralis muscle) should be considered as limiting factors if the Ober test is performed with the knee flexed. The rectus femoris is a muscle that crosses both the hip and the knee, which would also be stretched with the knee flexed, so length restrictions of this muscle and its fascia could have also
79
contributed to the limited hip adduction movement that was observed. The differences between the women and men were difficult to explain. One possible explanation, however, was that the increased weight of the menÕs limbs relative to that of the womenÕs limbs may have caused the menÕs limb to move into greater hip adduction with both knee positions. The study did not account for differences in the weights of the limbs or the longer lever arm of the limb with the knee extended. Further study is needed to explore these possibilities. Even so, the significant differences between the men and the women suggested that normal values should be established for men and women separately. Our results demonstrated the influence of knee flexion compared to knee extension on the angle of hip abduction or adduction for a small sample of nondisabled men and women, which were both more limited than the angles suggested by Kendall et al. (1993). Larger samples would need to be studied to confirm our preliminary findings. Normal values could then be used for objective and valid comparisons when examining patients with suspected pathologies that may be related to an abnormally short ITB.
References Hertling, D., Kessler, R., 1996. In: Management of Common Musculoskeletal Disorders, third ed. Lippincott, Philadelphia, p. 297. Hoppenfield, S., 1976. In: Physical Examination of the Spine and Extremities. Appleton-Century-Crofts, New York, p. 167. Kendall, F.P., McCreary, E.K., Provance, P.G., 1993. In: Muscles Testing and Function, fourth ed. Williams and Wilkins, Baltimore, p. 59. Magee, D.J., 1997. In: Orthopedic Physical Assessment, third ed. WB Saunders, Philadelphia, p. 483. Ober, F.R., 1936. The role of the iliotibial band and fascia lata as a factor in the causation of low-back disabilities and sciatica. J. Bone Jnt. Surg. 18, 105–110. Starkey, C., Ryan, J., 1996. In: Evaluation of Orthopedic and Athletic Injuries. FA Davis, Philadelphia, pp. 165–169.
Brief report
Influence of knee positions and gender on the Ober test for length of the iliotibial band Richard L Gajdosik *, Matthew M Sandler, Heather L Marr Clinical Kinesiology Laboratory, Physical Therapy Department, School of Pharmacy and Allied Health Sciences, The University of Montana, Missoula, MT 59812-4680, USA Received 22 May 2002; accepted 22 October 2002
Abstract Objective. Examine the influence of knee positions and gender on the Ober test for the length of the iliotibial band. Design. A cross-sectional comparative repeated measures design. Background. The Ober test is in widespread use, yet the influence of knee positions and gender on the test has not been reported. Such information is needed to help clarify test results. Methods. The Ober test was administered with the knee flexed to 90° and extended to 0° to the right lower limb of 26 women and 23 men. The limb was lowered from abduction and the end point of hip abduction (positive angle) or hip adduction (negative angle) was measured in relation to neutral. Results. The hip adduction movement was restricted more with the knee flexed than with the knee extended for both genders ðP < 0:009Þ. With the knee flexed the mean hip abduction angle was less for men ðþ4°Þ than for women ðþ6°Þ ðP < 0:001Þ, and with the knee extended the mean hip adduction angle was greater for men ð9°Þ than for women ð4°Þ ðP < 0:001Þ. Conclusion. The Ober test with the knee flexed limited hip adduction more than with the knee extended for both men and women, and women had greater limitations than men. Relevance The Ober test with the knee flexed and with the knee extended yielded different results and may be considered different tests. Normal Ober test values for the two knee positions should be defined separately for men and women in order to understand how deviations from normal are related to pathologies. Ó 2002 Elsevier Science Ltd. All rights reserved. Keywords: Ober test; Iliotibial band length; Hip range of motion
1. Introduction The Ober test, first described by Ober (1936), is a common and widely accepted test for measuring the length of the iliotibial band (ITB). The ITB, also known as the iliotibial tract, is a lateral thickening of the fascia lata of the thigh that has primary attachments to the ilium superiorly, and to the lateral tuberosity of the tibia, the head of the fibula, the lateral condyle of the zfemur and lateral patellar retinaculum inferiorly. The ITB also is continuous with the lateral intermuscular septum of the thigh that is anchored to the shaft of
*
Corresponding author. E-mail address: [email protected] (R. L Gajdosik).
the femur. The gluteus maximus and tensor fascia lata muscles insert into the ITB, which can be considered the tendon of these muscles. The Ober test is administered to the lower limb (upper) with the patient side lying. The examiner stands behind the patient and moves the thigh of the tested limb into flexion, abduction, and extension. While stabilizing the pelvis with one hand, the examiner then lowers the limb into adduction until it stops, or until the pelvis starts to tilt downward, or both. The length of the ITB is then represented by the hip abduction or adduction angle in relation to a neutral position (0°) (Kendall et al., 1993). Although Ober first described the test with the knee flexed, our search of the literature found no accepted standard knee position for the test and no published studies that objectively reported the influence of knee
0268-0033/03/$ - see front matter Ó 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 8 - 0 0 3 3 ( 0 2 ) 0 0 1 6 8 - 7
78
R. L Gajdosik et al. / Clinical Biomechanics 18 (2003) 77–79
flexion or knee extension on the testÕs results. Kendall et al. (1993) suggested that a normal ITB length would allow the thigh to drop slightly below horizontal (0°) with the knee flexed to 90°, and to about 10° below horizontal with the knee extended, but no objective data are available to support these guidelines. Moreover, gender differences have not been described. Most authorities have suggested that the knee should be flexed for the test as originally described by Ober (Kendall et al., 1993; Hoppenfield, 1976; Starkey and Ryan, 1996; Magee, 1997), but some have suggested that the test can also be modified by placing the knee in extension (Kendall et al., 1993; Magee, 1997; Hertling and Kessler, 1996). Although Kendall et al. (1993) indicated that hip adduction movement would be more limited with the knee flexed, others have suggested that the ITB has a greater stretch placed on it with the knee extended (Magee, 1997; Hertling and Kessler, 1996). If greater stretch is placed on the ITB with the knee extended, one would expect that this knee position would limit hip adduction movement more than with the knee flexed. Because of these conflicting opinions, and the lack of objective evidence to support published claims, we designed this study to examine the influence of two knee positions and gender on the hip abduction or adduction angle for the Ober test. The purposes of the study, therefore, were to examine the effects of knee flexion and knee extension on the Ober test and to compare independent samples of men and women.
2. Methods 2.1. Subjects Twenty-six non-disabled women (ages 20–43 years; mean 26, SD 5) and 23 non-disabled men (ages 23–37 years; mean 28, SD 4) participated with informed consent. The subjects had no history of hip or knee conditions that would confound the results and they all had passive knee flexion to at least 100°. The study was approved by The Institutional Review Board for the Use of Human Subjects in Research of The University of Montana. 2.2. Procedures A universal goniometer was used to measure hip abduction or adduction. Preliminary pilot work was completed to standardize the subject positioning, goniometer placement and instruction commands. One examiner (MMS) administered the test to the right limb with the knee held in either 0° of extension or in 90° of flexion, which were randomly ordered by a coin toss. Another examiner (HLM) positioned the goniometer,
and read and recorded the angle of hip abduction or adduction. Each knee position was tested 3 times within one test session. The reliability among the three trials (I C C , Model 2) for the women was 0.92 for knee extension and 0.87 for knee flexion. The I C C values for the men among the 3 trials were 0.82 for knee extension and 0.83 for knee flexion. The mean of the three trials was used for analysis. To prepare the subjects, a line was drawn on the midline anterior aspect of the right thigh between the anterior superior iliac spine and the patella. This line represented the longitudinal axis of the thigh and helped to ensure accurate alignment of the movable arm of the goniometer. Subjects were then positioned in left side lying on a treatment table with their shoulders and hips aligned perpendicular to the table. The left hip and knee were flexed to about 45° each, which helped to stabilize the pelvis and to prevent anterior tilting of the pelvis. The examiner stood behind the subject and stabilized the right side of the pelvis by pushing in a superior and downward direction with his left hand. With the right hand he grasped the subjectÕs right knee on its medial side and cradled the leg on his forearm with the knee either flexed or extended. The subjectÕs limb was then moved into hip flexion, abduction and extension, and then lowered into hip adduction. No medial rotation or flexion of the hip was allowed. The knee positions and neutral hip extension without hyperextension were confirmed with a goniometer by the second examiner before the limb was lowered. The end position of the thigh adduction movement was defined by the start of lateral tilting of the pelvis, or when movement stopped, or both. At this end position the second examiner aligned the stationary arm of the goniometer with both anterior superior iliac spines, aligned the moveable arm with the line drawn on the thigh, and then measured the angle of hip abduction or adduction. A neutral thigh position was defined as 0°. Abduction degrees were defined as positive and adduction degrees were defined as negative in relation to this neutral position. 2.3. Data analysis and results Descriptive statistics were tabulated for the hip abduction and adduction angles (Table 1). A two-way A N O V A for repeated measures showed that the angles were significantly less with the knee flexed than with the knee extended for both women and men combined ðP ¼ 0:009Þ. The men had greater adduction than the women for both knee positions ðP < 0:001Þ, and there was a significant interaction ðP ¼ 0:04Þ. Separate oneway A N O V A s indicated that knee flexion limited the hip adduction movement more than knee extension for both the women ðP < 0:001Þ and the men ðP < 0:001Þ (see Table 1).
R. L Gajdosik et al. / Clinical Biomechanics 18 (2003) 77–79 Table 1 Descriptive statistics for the results of the Ober test with the knee held at 0° of extension and 90° of flexion for the women ðn ¼ 26Þ and the men ðn ¼ 23Þ Mean
SD
Range
Women Knee extension (°) Knee flexion (°)
)4 þ6
þ5 þ5
)11 to þ5 )3 to þ16
Men Knee extension (°) Knee flexion (°)
)9 þ4
þ6 þ5
)20 to þ3 )4 to þ15
Positive numbers indicate hip abduction and negative numbers indicate hip adduction in relation to the neutral position of 0°.
2.4. Discussion The results indicated that knee flexion to 90° limited hip adduction movement more than with the knee held in 0° of extension, which is in agreement with the results suggested by Kendall et al. (1993). Because the ITB attaches into the lateral patellar reticulum, knee flexion probably lengthened the ITB, as well as the tensor fascia latae muscle by way of this attachment, and this contributed to the limited hip adduction movement. The ITB is continuous with the fascia lata of the anterior lateral aspect of the thigh, so stretching this aspect of the fascia lata with knee flexion also may have contributed to the limited hip adduction movement in addition to stretching the ITB alone. Greater tightness of the fascia lata over the anterior-lateral aspect of the thigh was obvious with palpation when the knee was flexed compared to when the knee was extended. Based on the objective goniometric results and our observations, it appeared that this part of the fascia latae, and perhaps other structures (i.e., vastus lateralis muscle) should be considered as limiting factors if the Ober test is performed with the knee flexed. The rectus femoris is a muscle that crosses both the hip and the knee, which would also be stretched with the knee flexed, so length restrictions of this muscle and its fascia could have also
79
contributed to the limited hip adduction movement that was observed. The differences between the women and men were difficult to explain. One possible explanation, however, was that the increased weight of the menÕs limbs relative to that of the womenÕs limbs may have caused the menÕs limb to move into greater hip adduction with both knee positions. The study did not account for differences in the weights of the limbs or the longer lever arm of the limb with the knee extended. Further study is needed to explore these possibilities. Even so, the significant differences between the men and the women suggested that normal values should be established for men and women separately. Our results demonstrated the influence of knee flexion compared to knee extension on the angle of hip abduction or adduction for a small sample of nondisabled men and women, which were both more limited than the angles suggested by Kendall et al. (1993). Larger samples would need to be studied to confirm our preliminary findings. Normal values could then be used for objective and valid comparisons when examining patients with suspected pathologies that may be related to an abnormally short ITB.
References Hertling, D., Kessler, R., 1996. In: Management of Common Musculoskeletal Disorders, third ed. Lippincott, Philadelphia, p. 297. Hoppenfield, S., 1976. In: Physical Examination of the Spine and Extremities. Appleton-Century-Crofts, New York, p. 167. Kendall, F.P., McCreary, E.K., Provance, P.G., 1993. In: Muscles Testing and Function, fourth ed. Williams and Wilkins, Baltimore, p. 59. Magee, D.J., 1997. In: Orthopedic Physical Assessment, third ed. WB Saunders, Philadelphia, p. 483. Ober, F.R., 1936. The role of the iliotibial band and fascia lata as a factor in the causation of low-back disabilities and sciatica. J. Bone Jnt. Surg. 18, 105–110. Starkey, C., Ryan, J., 1996. In: Evaluation of Orthopedic and Athletic Injuries. FA Davis, Philadelphia, pp. 165–169.